1. A drive cylinder, comprising:

a cylinder (10) having a piston chamber (14);

a piston assembly (20) including a piston (21) located in the piston chamber (14) and a piston rod (22) connected to the piston (21), the piston assembly (20) being reciprocally disposed along an axial direction of the cylinder (10); and

a braking device (30) in driving connection with the piston (21) and configured to brake the piston (21) and to release the brake to the piston (21).

2. A cylinder as claimed in claim 1, characterized in that the braking device (30) comprises a disc brake device or a linear brake device.

3. The drive cylinder of claim 1, wherein the brake device (30) comprises:

a static friction plate (31) which is fixed to the cylinder (10); and

and the dynamic friction plate (32) is in driving connection with the piston (21).

4. The drive cylinder of claim 1, further comprising a transmission (50), wherein the brake device (30) is connected to the piston assembly (20) via the transmission (50).

5. The drive cylinder according to claim 4, characterized in that the transmission (50) comprises a lead screw nut pair.

6. The drive cylinder of claim 5, wherein the piston assembly (20) has an axial mounting bore (23), and the lead screw nut assembly comprises:

a nut (51) disposed coaxially with the piston assembly (20) within the axial mounting bore (23) of the piston assembly (20); and

the first end of the lead screw (52) is fixedly connected with the braking device (30), the second end of the lead screw is positioned in the axial mounting hole (23), and the lead screw (52) is in threaded fit with the nut (51) or is in fit with the nut through balls.

7. The drive cylinder according to claim 6, characterized in that the cylinder body (10) comprises a cylinder barrel (11) and a first end cover (12) and a second end cover (13) respectively located at two axial ends of the cylinder barrel (11), the first end cover (12) has an inner space (123), the brake device (30) is located in the inner space (123), the end of the first end of the lead screw (52) extends into the inner space (123) of the first end cover (12), and the piston rod (22) passes through the second end cover (13).

8. The drive cylinder according to claim 7, characterized in that the end of the inner wall of the inner space (123) of the first end cap (12) remote from the cylinder barrel is provided with a mounting groove (122), and the tip of the first end of the lead screw (52) is located in the mounting groove (122).

9. The drive cylinder of claim 7, further comprising a screw bearing and sealing device (60), the screw bearing and sealing device (60) being disposed on the first end cap (12), the first end of the screw (52) being sealingly supported on the screw bearing and sealing device (60) to isolate the interior space (123) from the piston cavity (14).

10. The drive cylinder according to any one of claims 1 to 9, characterized by further comprising position detection means (40), the position detection means (40) being configured to detect axial position information representing an axial position of the piston (21) relative to the cylinder (10).

11. The drive cylinder of claim 10, wherein the position sensing device (40) comprises:

a first proximity switch (41) provided on the cylinder (10) and configured to detect first axial position information of the piston (21), the axial position information including the first axial position information; and

second proximity switches (42) provided on the cylinder (10) at intervals in an axial direction of the cylinder, configured to detect second axial position information of the piston (21), the axial position information including the second axial position information.

12. The drive cylinder according to claim 11, characterized in that the axial distance of the first proximity switch (41) and the second proximity switch (42) is equal to the axial length of the piston (21).

13. The drive cylinder of claim 10,

the driving cylinder comprises a transmission device (50), the transmission device (50) is positioned between the braking device (30) and the piston assembly (20), the braking device (30) and the piston assembly (20) are connected through the transmission device (50), and the transmission device (50) comprises a lead screw and nut pair;

the position detection device (40) includes an encoder (43), and the encoder (43) is configured to detect rotational angle information of a lead screw (52) of the lead screw-nut pair.

14. The drive cylinder of claim 13, wherein the position sensing device (40) further comprises a bevel gear pair (44), the bevel gear pair (44) comprising:

a first bevel gear (441) fixedly arranged at a first end of the screw (52); and

a second bevel gear (442) meshing with the first bevel gear (441), the encoder (43) being coaxially connected with the second bevel gear (442).

15. The drive cylinder according to any one of claims 1 to 9, characterized by further comprising a control device (70), the control device (70) being in signal connection with the position detection device (40) and the braking device (30) and being configured to issue a braking command to the braking device (30) to operate the braking device (30) to perform a braking action to brake the piston (21) when the axial position information indicates that the current axial position of the piston (21) coincides with a target locking position.

16. A vehicle steering system comprising a steering cylinder, characterised in that the steering cylinder is a drive cylinder according to any one of claims 1 to 15.

17. A vehicle comprising a vehicle steering system, characterized in that the vehicle steering system comprises the vehicle steering system of claim 16.

18. The vehicle of claim 17, characterized in that the vehicle steering system is used for rear axle steering of the vehicle.

Background

Engineering vehicles widely adopt a multi-axle steering technology. The multi-axis steering technology can be divided into a mechanical steering system, a hydraulic power steering system, a full hydraulic steering system, an electric control hydraulic steering system and the like. The multi-axle steering technology is mainly applied to the combined arrangement of front axle hydraulic power-assisted steering and rear axle electric control hydraulic steering, and the scheme is favorable for ensuring the safety and the reliability of a steering system and meeting the requirements of maneuverability and flexibility of a multi-axle steering vehicle.

The electrically controlled hydraulic steering system comprises an electric part and a mechanical part. The electric part is mainly composed of various sensor Control units, such as a vehicle speed sensor, a wheel rotation angle sensor, an ECU (Electronic Control Unit), and the like. The mechanical part comprises an electric proportional direction valve, a steering cylinder, an oil pipe, a pump and the like.

In the related technology known by the inventor, the working principle of a steering cylinder of an electrically controlled hydraulic steering system is the same as that of a common hydraulic cylinder, when the steering system steers, oil pushes a piston to move so as to drive a piston rod to stretch, and a steering knuckle and wheels are driven to rotate through mechanisms such as a steering pull rod, a steering knuckle arm and the like connected with the piston rod.

The steering cylinder is a direct execution element in a vehicle steering system for steering a rear axle of a vehicle, the control mode of the steering cylinder is relatively independent, and the flow and the direction of oil are directly controlled by an electric proportional directional valve to realize the control of the steering speed and the steering direction. The angle sensor arranged on the rear wheel is used for monitoring the rotation quantity of the wheel in real time, the ECU acquires data of the angle sensor as one of the steering bases, and meanwhile, the rear wheel steering angle is fed back to the ECU in real time in the steering process, so that the dynamic compensation of the wheel steering angle is realized, and the accurate control of the wheel steering angle is finally achieved.

In order to meet the reliability and safety of the multi-axle steering system, a middle locking oil cylinder is required to be arranged in the vehicle steering system for steering the rear axle. The middle position locking oil cylinder is a hydraulic cylinder with a special structure, two pistons are arranged in the cylinder body, the cylinder body is divided into three chambers, the tail part of a piston rod is positioned in the middle chamber, the two pistons are in a floating state when the middle position locking oil cylinder normally turns, the piston rod can freely stretch and retract along with the turning action of a system, when the middle position locking oil cylinder needs to be locked, the chambers at the two ends are filled with oil, the middle chamber returns oil, the two pistons move to a middle limiting block, the piston rod is limited to be positioned in the middle position, and the purpose of locking the middle position is achieved.

In the above related art, for a heavy vehicle, a single steering cylinder often cannot provide sufficient steering force, so that two steering cylinders and a center lock cylinder are generally required to be arranged on one axle.

Disclosure of Invention

The purpose of this disclosure is to provide a driving cylinder, vehicle steering system and vehicle.

A first aspect of the present disclosure provides a drive cylinder, comprising:

a cylinder having a piston chamber;

the piston assembly comprises a piston positioned in the piston cavity and a piston rod connected with the piston, and the piston assembly is arranged in a reciprocating manner along the axial direction of the cylinder body; and

a braking device in driving connection with the piston and configured to brake and brake the piston.

In the drive cylinder of some embodiments, the brake device includes a disc brake device or a linear brake device.

In the drive cylinder of some embodiments, the brake device includes:

the static friction plate is fixedly arranged opposite to the cylinder body; and

and the dynamic friction plate is in driving connection with the piston.

In some embodiments, the drive cylinder further comprises a transmission, and the brake device is connected with the piston assembly through the transmission.

In some embodiments, the drive cylinder includes a lead screw nut pair.

In the drive cylinder of some embodiments, the piston assembly has an axial mounting bore, and the lead screw nut assembly includes:

a nut disposed within the axial mounting bore of the piston assembly coaxially with the piston assembly; and

and the first end of the lead screw is fixedly connected with the braking device, the second end of the lead screw is positioned in the axial mounting hole, and the lead screw is in threaded fit with the nut or is in fit with the nut through a ball.

In some embodiments, the cylinder body includes a cylinder barrel, and a first end cover and a second end cover respectively located at two axial ends of the cylinder barrel, the first end cover has an inner space, the brake device is located in the inner space, a tip of the first end of the lead screw extends into the inner space of the first end cover, and the piston rod passes through the second end cover.

In some embodiments, an installation groove is formed in one end, away from the cylinder barrel, of the inner wall of the inner space of the first end cover, and the end of the first end of the lead screw is located in the installation groove.

In some embodiments, the drive cylinder further comprises a lead screw bearing and sealing device disposed on the first end cap, the first end of the lead screw being sealingly supported on the lead screw bearing and sealing device to isolate the interior space from the piston cavity.

In the drive cylinder of some embodiments, further comprising position detecting means configured to detect axial position information representing an axial position of the piston relative to the cylinder body.

In the drive cylinder of some embodiments, the position detecting means includes:

a first proximity switch disposed on the cylinder configured to detect first axial position information of the piston, the axial position information including the first axial position information; and

the second proximity switch is arranged on the cylinder body at intervals along the axial direction of the cylinder body and is configured to detect second axial position information of the piston, and the axial position information comprises the second axial position information.

In some embodiments, the drive cylinder has an axial distance between the first proximity switch and the second proximity switch that is equal to an axial length of the piston.

In the drive cylinder of some embodiments,

the driving cylinder comprises a transmission device, the transmission device is positioned between the braking device and the piston assembly, the braking device is connected with the piston assembly through the transmission device, and the transmission device comprises a lead screw and nut pair;

the position detection device includes an encoder configured to detect rotational angle information of a lead screw of the lead screw-nut pair.

In the drive cylinder of some embodiments, the position detecting device further includes a bevel gear pair including:

the first bevel gear is fixedly arranged at the first end of the lead screw; and

and the second bevel gear is meshed with the first bevel gear, and the encoder is coaxially connected with the second bevel gear.

In some embodiments, the control device is in signal connection with the position detection device and the braking device, and is configured to issue a braking command to the braking device to operate the braking device to perform a braking action to brake the piston when the axial position information indicates that the current axial position of the piston is consistent with a target locking position.

A second aspect of the present disclosure provides a vehicle steering system comprising the drive cylinder of the first aspect of the present disclosure.

A third aspect of the present disclosure provides a vehicle including the vehicle steering system of the second aspect of the present disclosure.

In some embodiments, the vehicle steering system is for rear axle steering of the vehicle.

According to the driving cylinder provided by the disclosure, the braking device is in driving connection with the piston, so that the braking device can brake and brake the piston. When the brake device performs a braking operation to brake the piston, the position of the piston assembly of the drive cylinder relative to the cylinder block is locked, and when the brake device does not perform the braking operation, the piston is released from the braking, and the position of the piston relative to the cylinder block is controlled by a control oil passage that drives the operation of the drive cylinder. Therefore, the driving cylinder can realize position adjustment and position locking of the piston and the piston assembly.

When the driving cylinder is adopted as a steering cylinder in a vehicle steering system, the steering cylinder can realize the steering function and simultaneously undertake the position locking function, so that a middle locking oil cylinder is not required to be additionally arranged, the integration level of the vehicle steering system is improved, and the cost of the vehicle steering system is reduced.

Other features of the present disclosure and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the disclosure and together with the description serve to explain the disclosure and not to limit the disclosure. In the drawings:

fig. 1 is a main structural schematic diagram of a driving cylinder according to an embodiment of the present disclosure.

Fig. 2 is a main structural schematic diagram of a driving cylinder according to another embodiment of the present disclosure.

Fig. 3 is a control schematic block diagram of the embodiment shown in fig. 1 and 2.

Detailed Description

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.

The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present disclosure, it should be understood that the terms "first", "second", etc. are used to define the components, and are used only for convenience of distinguishing the corresponding components, and if not otherwise stated, the terms have no special meaning, and thus, should not be construed as limiting the scope of the present disclosure.

In the description of the present disclosure, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are presented only for the convenience of describing and simplifying the disclosure, and in the absence of a contrary indication, these directional terms are not intended to indicate and imply that the device or element being referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore, should not be taken as limiting the scope of the disclosure; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

In the process of implementing the present disclosure, the inventor finds that when a steering cylinder of a vehicle steering system in the related art needs to lock a piston position, an additional middle position locking oil cylinder needs to be arranged, which results in low integration level of the vehicle steering system, and is not beneficial to reducing space and saving cost. In addition, the middle locking oil cylinder can only lock the vehicle running position in a straight line running state, and the functional requirement of locking at any position cannot be met. Because the rear wheel steering angle data acquisition needs an angle sensor, certain arrangement space is needed, and the cost is not reduced.

As shown in fig. 1 to 3, the present embodiment provides a driving cylinder including a cylinder body 10, a piston assembly 20, and a brake device 30. The cylinder 10 has a piston chamber 14. The piston assembly 20 includes a piston 21 located in the piston chamber 14 and a piston rod 22 connected to the piston 21, and the piston assembly 20 is disposed to be reciprocally movable in the axial direction of the cylinder 10. The brake device 30 is drivingly connected to the piston 21 and configured to brake the piston 21 and to release braking from the piston 21.

According to the driving cylinder of the embodiment of the present disclosure, since the braking device 30 which is in driving connection with the piston 21 is included, the braking device can brake the piston 21 and release braking to the piston 21. When the brake device 30 performs a braking operation to brake the piston 21, the position of the piston assembly 20 of the drive cylinder with respect to the cylinder 10 is locked, and when the brake device 30 does not perform a braking operation, the piston 21 is released from the braking, and the position of the piston 21 with respect to the cylinder 10 is controlled by a control oil passage that drives the operation of the drive cylinder. Therefore, the position adjustment and position locking of the piston 21 and the piston assembly 20 can be realized by adopting the driving cylinder of the disclosed embodiment.

When the driving cylinder is adopted as a steering cylinder in a vehicle steering system, the steering cylinder can realize the steering function and simultaneously undertake the position locking function, so that a middle locking oil cylinder is not required to be additionally arranged, the integration level of the vehicle steering system is improved, and the cost of the vehicle steering system is reduced.

The braking device 30 may comprise a disc brake device, and the locking of the piston position is achieved by braking the rotational movement, and the control mode may be a hydraulic control type or an electric control type braking device. The braking device 30 may also comprise a linear braking device, such as a rail-type, electromagnetic linear braking mechanism.

In the embodiment shown in fig. 1 to 3, the braking device 30 comprises a disc braking device, in particular a static friction disc 31 and a dynamic friction disc 32. The static friction sheet 31 is disposed fixedly relative to the cylinder 10. The dynamic friction plate 32 is in driving connection with the piston 21. Therefore, braking and braking release of the piston 21 and the piston assembly 20 can be achieved by engagement and disengagement between the dynamic friction plates 32 and the static friction plates 31. When the piston 21 and the piston assembly 20 are braked by the brake device 30, the position of the piston 21 and the piston assembly 20 with respect to the cylinder 10 is locked, and when the piston 21 and the piston assembly 20 are released from braking, the position of the piston 21 and the piston assembly 20 is controlled by a hydraulic oil passage that drives the operation of the drive cylinder.

In some embodiments, as shown in fig. 1 and 2, the drive cylinder further includes a transmission 50. The brake device 30 is connected to the piston assembly 20 via a transmission 50. The transmission 50 is located between the brake device 30 and the piston assembly 20.

In some embodiments, the transmission 50 may comprise a lead screw nut pair, for example. The screw-nut pair is simple and reliable in transmission, facilitates long-distance and variable-distance braking by adopting a disc type braking device, and facilitates locking of the piston 21 and the piston assembly 20 of the driving cylinder at a required target locking position.

As shown in fig. 1-3, in some embodiments, the drive cylinder further includes a position detection device 40, the position detection device 40 being configured to detect axial position information representative of an axial position of the piston 21 relative to the cylinder body 10. The position detection device 40 is arranged to facilitate the determination of the real-time axial position of the piston 21, and to facilitate the judgment of whether the piston 21 and the piston assembly 20 reach the position to be locked, so as to reasonably determine the braking timing of the braking device 30.

The position detection device 40 may include one or more position monitoring sensors. The position monitoring sensor used may be, for example, a proximity switch, an encoder 43, etc., which can meet the requirements of a specific position or continuous position detection function of the piston 21 of the drive cylinder. The position detecting device 40 may be integrated with the cylinder 10 or may be disposed on an external structure, and the position of the piston 21 may be indirectly obtained by monitoring the movement of the external structure.

As shown in fig. 1, in some embodiments, the position detection device 40 includes a first proximity switch 41 and a second proximity switch 42. The first proximity switch 41 is provided on the cylinder 10 and configured to detect first axial position information of the piston 21. The second proximity switches 42 are provided on the cylinder 10 at intervals in the axial direction of the cylinder, and are configured to detect second axial position information of the piston 21. The axial position information includes first axial position information and second axial position information.

In some embodiments, the axial distance of the first proximity switch 41 and the second proximity switch 42 is equal to the axial length of the piston 21. This arrangement facilitates determination as to whether the piston 21 reaches the specified target lock position.

As shown in fig. 2, in some embodiments, the driving cylinder includes a transmission device 50, the transmission device 50 is located between the braking device 30 and the piston assembly 20, the braking device 30 and the piston assembly 20 are connected through the transmission device 50, and the transmission device 50 includes a lead screw and nut pair; the position detection device 40 may include an encoder 43, the encoder 43 being configured to detect rotational angle information of the lead screw 52 of the lead screw-nut pair, and the axial position information including the rotational angle information.

As shown in FIG. 2, in some embodiments, the position sensing device 40 further includes a bevel gear pair 44, and the bevel gear pair 44 includes a first bevel gear 441 and a second bevel gear 442. The first bevel gear 441 is fixedly disposed at a first end of the lead screw 52. The second bevel gear 442 is engaged with the first bevel gear 441, and the encoder 43 is coaxially connected with the second bevel gear 442.

The encoder 43 can measure the rotation angle of the lead screw 52, and the rotation angle can be further converted into the axial movement distance of the nut 51 engaged with the lead screw 52, that is, the movement distance of the piston 21 can be obtained, so that the axial position of the piston 21 can be calculated. Wherein the provision of the bevel gear pair 44 facilitates a flexible arrangement of the encoders.

As shown in fig. 1-3, in some embodiments, the drive cylinder further includes a control device 70. The control device 70 is in signal connection with the position detection device 40 and the braking device 30 and is configured to issue a braking command to the braking device 30 to operate the braking device 30 to perform a braking action to brake the piston 21 when the axial position information indicates that the current axial position of the piston 21 coincides with the target locking position.

In this embodiment, the control device 70 is in signal connection with the position detecting device 40 and the braking device 30, and sends a braking command to the braking device 30 to brake the piston 21 according to the axial position information of the piston 21 and the target locking position, so that the position of the piston 21 and the piston assembly 20 relative to the cylinder 10 can be locked when the piston 21 reaches the target locking position, which is beneficial to accurately locking the piston 21 and the piston assembly 20 at the target locking position.

Control device 70 may be implemented as a general purpose Processor, a Programmable Logic Controller (PLC), a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable Logic device, discrete Gate or transistor Logic, discrete hardware components, or any suitable combination thereof for performing the functions described in this disclosure.

While the bit lock cylinder in the vehicle steering system of the related art can only lock the vehicle driving position in a straight driving state, the driving cylinder of the embodiment of the present disclosure, due to the provision of the control device 70 and the position detection device 40, can be configured to lock the position of the piston assembly 20 according to a target locking position given by the control device 70, which is beneficial to meet the functional requirements of more position locking. Because the axial displacement information acquisition function of the piston 21 is integrated into the driving cylinder, when the driving cylinder is used as a steering cylinder of a vehicle steering system, an angle sensor for detecting the rotation quantity of wheels does not need to be arranged independently, thereby being beneficial to improving the integration level of the vehicle steering system and reducing the cost of the vehicle steering system.

The present disclosure also provides a vehicle steering system including the drive cylinder of the foregoing embodiment. The vehicle steering system using the drive cylinder has the advantages of the drive cylinder of the foregoing embodiment. Because the middle locking oil cylinder is not needed, the integration level is relatively high, the space is reduced, and the cost is saved.

The embodiment of the disclosure also provides a vehicle, which comprises the vehicle steering system of the embodiment. For example, a vehicle steering system is used for a rear axle steering system that drives a rear axle to rotate. The vehicle may typically be a work vehicle. The vehicle has the same advantages as the vehicle steering system of the embodiment of the present disclosure.

The structure and operation of the driving cylinder according to some embodiments of the present disclosure will be further described with reference to fig. 1 to 3.

As shown in fig. 1 to 3, the driving cylinder includes a cylinder block 10, a piston assembly 20, a braking device 30, a position detecting device 40, a transmission mechanism 50, a screw supporting and sealing device 60, and a control device 70.

The cylinder 10 has a piston chamber 14 including a cylinder 11 and first and second end caps 12 and 13 respectively located at both axial ends of the cylinder 11. As shown in fig. 1 and 2, the first end cap 12 is located at the left end of the cylinder, and the second end cap 13 is located at the right end of the cylinder 11. The central bore of the cylinder 11 constitutes a piston chamber 14. The first end cap 12 has an interior space 123 therein. The right end of the outer side of the first end cover 12 is connected with a ball head connecting structure G. When the driving cylinder is used as a steering cylinder in a vehicle steering system, the ball joint structure G is connected to other components of the vehicle steering system, such as a tie rod.

The piston assembly 20 includes a piston 21 and a piston rod 22 connected to the piston 21. The piston assembly 20 is reciprocally disposed along the axial direction of the cylinder 10, and the piston 21 is located in the piston chamber 14 of the cylinder 10. A first end of the piston rod 22 is fixedly connected to the piston 21, and the piston rod 22 may, for example, be provided integrally with the piston. The piston assembly 20 has an axial mounting bore 23 therein. The axial mounting bore 23 is a blind bore extending from a first end to a second end of the piston assembly 20. The second end of the piston rod 22 projects to the right through the second end cap 13. As shown in fig. 1 and 2, the second end of the piston rod 22 is connected to a ball joint structure G, which is connected to other components of the vehicle steering system, such as a tie rod, when the driving cylinder is used as a steering cylinder in the vehicle steering system.

The braking device 30 is in driving connection with the piston 21. The brake device 30 is used to brake the piston 21 and release the brake to the piston 21. As shown in fig. 1 and 2, the brake device 30 is a disc brake device, and specifically includes a static friction plate 31 and a dynamic friction plate 32. The brake 30 is located within the interior space 123 of the first endcap 12. The static friction sheet 31 is fixedly disposed opposite to the cylinder 10, and as shown in fig. 1 and 2, the static friction sheet 31 is fixed to the first end cap 12. The dynamic friction plate 32 and the piston 21 are drivingly connected to the piston 21 via a spindle nut pair as a transmission 50. Therefore, the control device 70 can brake and release the brake of the piston 21 and the piston assembly 20 by engaging and disengaging the dynamic friction plates 32 and the static friction plates 31. As shown in fig. 1 and 2, the brake device 30 is operated in a pilot-controlled manner. When the piston 21 and the piston assembly 20 are braked by the brake device 30, the positions of the piston 21 and the piston assembly 20 are locked, and when the piston assembly 20 is released from braking, the positions of the piston 21 and the piston are controlled by a hydraulic oil passage that drives the operation of the drive cylinder. The hydraulic oil path includes a brake oil passage 121 provided in the first cover 12 for flowing hydraulic oil for controlling the operation of the dynamic friction plates 32 of the brake device 30.

The position detection device 40 is configured to detect axial position information of the piston 21 with respect to the cylinder 10. As shown in fig. 1, the position detection device 40 includes a first proximity switch 41 and a second proximity switch 42.

The transmission device 50 is located between the brake device 30 and the piston assembly 20, and the brake device 30 and the piston assembly 20 are connected through the transmission device 50. As shown in fig. 1 and 2, the transmission mechanism 50 includes a lead screw nut pair. The screw-nut pair includes a nut 51 and a screw 52. The nut 51 and the piston assembly 20 are detachably and coaxially arranged in the axial mounting hole 23 of the piston assembly 20 through a screw. The first end of the screw 52 is fixedly connected with the dynamic friction plate 32 of the braking device 30, the second end is located in the axial mounting hole 23, and the screw 52 is in threaded fit with the nut 51 or is in ball fit with the nut. The arrangement ensures that the transmission device has simple structure, stable transmission and easy and accurate locking of the position of the piston and timely unlocking.

As shown in fig. 1 and 2, the brake device 30 is located in the inner space 123 of the first end cap 12, the end of the first end of the lead screw 52 extends into the inner space 123 of the first end cap 12, and the piston rod 22 passes through the second end cap 13. The arrangement is favorable for reasonable layout of all moving parts of the driving cylinder and is favorable for preventing interference among all moving parts of the driving cylinder.

As shown in fig. 1 and fig. 2, the screw-nut pair transmits the translation of the piston 21 to the braking device 30 in the form of rotation of the screw 52, the first end of the screw 52 is connected to the dynamic friction plate 32 of the braking device 30, and the dynamic friction plate 32 is fixed, so that the braking of the screw 52, that is, the piston position locking of the driving cylinder, can be realized.

A screw bearing and sealing device 60 is disposed on the first end cap 12, and a first end of the screw 52 is sealingly supported on the screw bearing and sealing device 60 to isolate the interior space 123 from the piston chamber 14. This arrangement is advantageous in preventing leakage of the gap between the lead screw 52 and the first end cap 12, in stabilizing the operation of the drive cylinder, and in positioning the piston 21 at an accurate operating position.

As shown in fig. 1 and 2, the screw supporting and sealing device 60 is located in the first accommodating cavity and fixed on the first end cap 12, the screw supporting and sealing device 60 has a central hole, and the screw 52 is inserted into the central hole of the supporting and sealing device 60 so as to be supported on the supporting and sealing device 60. A sealing structure, such as a seal ring, a graphite packing, etc., may be provided between the central bore of the bearing and sealing device 60 and the lead screw 52 to provide a seal therebetween to prevent leakage from the gap between the lead screw and the first end cap 12.

As shown in fig. 1 and 2, an installation groove 122 is formed in an end of the inner wall of the inner space 123 of the first end cover 12, which is far away from the cylinder, and the end of the first end of the screw 52 is located in the installation groove 122. This arrangement facilitates better support of the lead screw 52, thereby facilitating reduction of deformation of the lead screw 52, e.g., preventing jamming of the piston 21 during axial movement.

The control device 70 is in signal connection with the braking device 30 and the position detection device 40. When the axial position information detected by the position detecting device 40 indicates that the current axial position of the piston 21 coincides with the target lock position, the control device 70 issues a braking command to the braking device 30 to operate the braking device 30 to perform a braking action to brake the piston 21.

In the embodiment shown in fig. 1, the first proximity switch 41 of the position detection device 40 is in signal connection with the control device 70 and is configured to detect first axial position information of the piston 21, the axial position information including the first axial position information, and the second proximity switch 42 of the position detection device 40 is in signal connection with the control device 70 and is configured to detect second axial position information of the piston 21, the axial position information including the second axial position information.

In this embodiment, the control device 70 is in signal connection with the position detecting device 40 and the braking device 30, and sends a braking command for operating the braking device 30 to perform a braking action to the braking device 30 according to the axial position information of the piston 21 and the target locking position, so as to lock the position of the piston 21 and the piston assembly 20 relative to the cylinder 10, thereby eliminating the need to separately provide a position locking cylinder, such as a middle position locking cylinder, outside the driving cylinder when there is a demand for locking the position of the driving cylinder.

In a vehicle steering system employing the drive cylinder of the embodiment shown in fig. 1 as a steering cylinder, the position detecting means 40 includes an arrangement of a first proximity switch 41 and a second proximity switch 42 adapted to lock the piston 21 at a specific target locking position.

As shown in fig. 1 and 3, in a normal steering condition, the braking device 30 does not work (does not perform a braking action), the screw 52 is driven by the nut 51 to rotate freely, the piston 21 is pushed left and right under the action of oil, and the ball head connecting structure G connected with the piston 21 makes a telescopic motion relative to the cylinder 10, so as to drive other components of the vehicle steering system to act, thereby realizing normal left and right steering.

When the position of the piston 21 needs to be locked, the control device 70 firstly judges the position of the piston 21 according to the axial position information of the piston 21 and sends a control command to move the piston 21 to the target locking position until the piston 21 moves to the target locking position, which is the position between the two proximity switches in the embodiment shown in fig. 1, and when the control device 70 detects signals of the two proximity switches, the control device controls a hydraulic valve of a hydraulic oil path driving the piston 21 to move to close so as to stop oil supply, opens a brake oil path of the brake device 30, the static friction plate 31 is attached to the dynamic friction plate 32, and the positions of the lead screw 52, the piston 21, the piston assembly 20 and the ball head connecting structure G connected with the piston rod 22 are locked.

The arrangement of two proximity switches to detect the axial position of the piston 21 can realize the locking of the piston 21 at a specific target locking position, which not only meets the requirement of accurate positioning of the piston 21, but also enables the piston 21 to move to the target locking position in the correct direction after a locking instruction is issued. Because the proximity switches all have signals within the axial length range of the piston 21, whether the piston 21 moves to the locking position cannot be accurately judged through whether one proximity switch has a signal, two proximity switches are arranged, the axial distance between the two proximity switches is equal to the axial length of the piston 21, at the moment, the control device 70 judges that the piston 21 is at the designated position only under the condition that the two proximity switch signals are received simultaneously, and the piston 21 does not reach the designated locking position under other conditions.

Another important reason for providing two switches is that the control system, upon receiving a command to lock the piston 21 at a given target locking position, can control the piston 21 to move toward the given target locking position for the first time without moving away from the target locking position in the opposite direction. The logic to implement this function is: after the control device 70 receives a signal for locking the piston 21 at a specified target locking position, it first determines the proximity switch that has acquired the position of the piston 21 for the last time, such as the first proximity switch 41 on the left side, and determines that the piston 21 is on the left side, and then controls the oil to push the piston 21 to move to the right until the target locking position is reached, and vice versa.

The arrangement of two proximity switches in fig. 1 is only one example of the position detection device, and the arrangement of the position detection device may be various as long as it can provide information on the axial position of the piston. For example, based on the embodiment shown in fig. 1, if the piston is to be locked at a plurality of specific target locking positions, the number of proximity switches in signal connection with the control device 70 may be increased, and the positions of the proximity switches may be appropriately set, i.e., which target locking position the piston is to be locked at may be selected.

The embodiment shown in fig. 2 differs from the embodiment shown in fig. 1 in the structure of the position detection means 40. As shown in fig. 2, the position detection device 40 includes an encoder 43 and a bevel gear pair 44.

As shown in fig. 2, the encoder 43 is configured to detect rotational angle information of the lead screw 52, and the axial position information includes the rotational angle information. Bevel gear pair 44 includes a first bevel gear 441 and a second bevel gear 442. A first bevel gear 441 is positioned within the interior space 123 and is fixedly disposed at a first end of the lead screw 52. Second bevel gear 442 is located within interior space 123 and is in meshing engagement with first bevel gear 441. The encoder 43 is coaxially connected to the second bevel gear 442. The encoder 43 can measure the rotation angle of the lead screw 22 by measuring the rotation angle of the second bevel gear 442 and feed back the rotation angle information to the control device 70 in real time, and the control device 70 can measure the axial position of the piston 21 by using the rotation angle information.

In a vehicle steering system employing the drive cylinder of the embodiment shown in fig. 2 as a steering cylinder, the position detecting means 40 includes an encoder 43 disposed in such a manner as to be adapted to lock the piston 21 at an arbitrary target lock position within a certain range. Since the encoder 43 collects the continuous rotation angle information of the screw 52, and the rotation amount of the screw 52, the expansion amount of the piston 21 and the rotation angle of the wheel have a one-to-one correspondence relationship, the rotation amount of the wheel can be calculated by obtaining the rotation angle information and the transmission relationship, and thus, the wheel angle monitoring function has been actually integrated into the driving cylinder in the vehicle steering system.

As shown in fig. 2 and 3, under a general steering condition, the piston 21 is pushed under the action of oil, the braking device 30 does not work, the screw-nut pair moves along with the piston 21, the vehicle steering system realizes normal left and right steering, meanwhile, the control device 70 collects data of the encoder 43 in real time to judge the rotation amount of the wheels, and stops oil supply after the wheels rotate by a specified deflection amount, so that real-time feedback and accurate control of steering are realized.

After receiving a command for locking the piston 21 at a certain target locking position, the control device 70 collects data from the encoder 43 to obtain the current axial position of the piston 21, calculates the moving direction and the moving amount of the next piston 21, and sends a braking command to enable the braking device 30 to perform a braking action after controlling the oil to push the piston 21 to reach the predetermined target locking position, so as to lock the position of the piston 21.

When the tire is required to reach a certain tire target position and be locked, the control device 70 firstly collects the data of the encoder 43, calculates the positions of the piston 21 and the tire, judges the moving direction and speed of the piston 21 in the next step according to the information, so as to control the direction and the flow of the oil, after the control device 70 detects that the tire moves to a specified position, the control device 70 sends a braking instruction to the braking device 30, and the braking device 30 is operated to perform a braking action so as to lock the position of the piston 21, so that the wheel position is locked.

From the above description, it can be seen that the above embodiments of the present disclosure provide a driving cylinder that integrates a locking function at a specific position or any position within a certain range. The driving cylinder can be applied to vehicles, such as a steering cylinder used in a vehicle steering system of an engineering vehicle, and the steering cylinder is integrated with a middle locking function of a middle locking oil cylinder, so that the middle locking oil cylinder is not required to be arranged, the integration level of the vehicle steering system can be improved, and the production cost is reduced.

Finally, it should be noted that: the above examples are intended only to illustrate the technical solutions of the present disclosure and not to limit them; although the present disclosure has been described in detail with reference to preferred embodiments, those of ordinary skill in the art will understand that: modifications to the embodiments of the disclosure or equivalent replacements of parts of the technical features may be made, which are all covered by the technical solution claimed by the disclosure.