1. A helical gear speed reducer with adjustable clearance, which is characterized in that: comprises a shell, a first-stage planetary gear train and a second-stage helical gear less tooth difference gear train which is connected with the first-stage planetary gear train in a transmission way; the second-stage helical gear train with few tooth difference comprises two pairs of inner meshing helical gear pairs and clearance eliminating mechanisms, one pair of the inner meshing helical gear pairs consists of a left-handed outer helical gear and an inner helical gear ring in sliding fit with the shell, and the other pair of the inner meshing helical gear pairs consists of a right-handed outer helical gear and an inner helical gear ring in sliding fit with the shell; the right-handed outer helical gear and the left-handed outer helical gear are arranged on the crankshaft; the anti-backlash mechanism comprises two pairs of inner-meshing helical gear pairs with opposite rotation directions and the same modulus and tooth number and an elastic element arranged at one end of an anti-backlash inner helical gear ring; and the shell is provided with an adjusting screw which penetrates through the shell to be in contact with the elastic element and adjust the pressing force of the elastic element.

2. The adjustable clearance helical gear reducer of claim 1, wherein: the left-handed helical gear and the right-handed helical gear are inserted into the input disc and the output disc respectively, and the output disc is connected with the right-handed helical gear and the left-handed helical gear respectively; the other end of the crankshaft is connected to a first stage planetary gear train.

3. The adjustable clearance helical gear reducer of claim 2, wherein: the first-stage planetary gear train comprises a sun gear shaft and a planet gear, wherein the sun gear shaft serves as input, the planet gear is matched with the sun gear, the sun gear shaft is connected with the motor, and the planet gear is inserted on the crank shaft in a penetrating mode and is matched with the crank shaft through a spline.

4. The adjustable clearance helical gear reducer of claim 2, wherein: an output disc bearing is arranged between the output disc and the shell to support the output disc.

5. The adjustable clearance helical gear reducer of claim 3, wherein: the two sides of the planet wheel are provided with check rings, and the planet wheel is axially limited by the check rings and a shaft shoulder of the crank shaft.

6. The adjustable clearance helical gear reducer of claim 3, wherein: an input end cover is fixed on the shell, the input end cover and the input disc are supported through an angular contact ball bearing, and the output disc and the shell are fixed through the angular contact ball bearing.

7. The adjustable clearance helical gear reducer of claim 2, wherein: the corresponding shaft sections of the crankshaft for supporting the right-handed outer helical gear and the left-handed outer helical gear are eccentric shaft sections, are correspondingly provided with eccentric bearings and are respectively used for supporting the right-handed outer helical gear and the left-handed outer helical gear, and the shaft sections for supporting the rotation of the crankshaft are non-eccentric shaft sections and are provided with crank bearings.

8. The adjustable clearance helical gear reducer of claim 3, wherein: deep groove ball bearings are installed at two ends of the sun gear shaft and used for supporting the sun gear shaft, and the deep groove ball bearings are axially positioned by a retaining shoulder of the input disc, a retaining shoulder of the input end cover and a shaft shoulder of the input shaft.

9. The adjustable clearance helical gear reducer of claim 1, wherein: the elastic element is a disc spring, and a gasket is arranged between the disc spring and the adjusting screw.

10. The adjustable gap helical gear reducer according to any one of claims 1 to 9, wherein: a plurality of adjusting screws which are uniformly distributed and arranged are arranged on the circumference of the shell corresponding to the disc spring.

Background

The RV transmission is a newly-emerging transmission, is developed on the basis of the traditional needle pendulum planetary transmission, not only overcomes the defects of the common needle pendulum transmission, but also has a series of advantages of small volume, light weight, large transmission ratio range, long service life, stable precision, high efficiency, stable transmission and the like. Increasingly receiving wide attention at home and abroad. The RV reducer is composed of a cycloidal pin wheel and a planet support, and has the advantages of small size, strong impact resistance, large torque, high positioning precision, small vibration, large reduction ratio and the like, and is widely applied to the fields of industrial robots, machine tools, medical detection equipment, satellite receiving systems and the like. Meanwhile, the transmission device has the advantages that other transmissions cannot be replaced in some fields due to the unique characteristics of flexible assembly and structure, the output value reaches hundreds of millions of yuan in recent years, and the transmission device has a wide application prospect. However, the speed reducer has the problems of large vibration and noise, high temperature rise, early bearing damage and the like under the conditions of high speed and heavy load due to the problems of installation errors, manufacturing errors, gear abrasion and the like of a gear pair, the problems are more prominent under the working conditions of continuous operation, heavy load, high speed and large transmission ratio, the popularization process of the speed reducer is greatly influenced, and the side clearance can not meet the requirements of a transmission device with high motion precision and small return difference.

Disclosure of Invention

In view of the above, the present invention provides an adjustable-gap helical gear speed reducer to solve the problem of backlash of the conventional transmission gear pair with less tooth difference.

In order to achieve the purpose, the invention provides the following technical scheme:

a helical gear speed reducer with adjustable clearance comprises a shell, a first-stage planetary gear train and a second-stage helical gear less-tooth-difference gear train which is connected with the first-stage planetary gear train in a transmission manner; the second-stage helical gear train with few tooth difference comprises two pairs of inner meshing helical gear pairs and clearance eliminating mechanisms, one pair of the inner meshing helical gear pairs consists of a left-handed outer helical gear and an inner helical gear ring in sliding fit with the shell, and the other pair of the inner meshing helical gear pairs consists of a right-handed outer helical gear and an inner helical gear ring in sliding fit with the shell; the right-handed outer helical gear and the left-handed outer helical gear are arranged on the crankshaft; the anti-backlash mechanism comprises two pairs of inner-meshing helical gear pairs with opposite rotation directions and the same modulus and tooth number and an elastic element arranged at one end of an anti-backlash inner helical gear ring; and the shell is provided with an adjusting screw which penetrates through the shell to be in contact with the elastic element and adjust the pressing force of the elastic element.

Optionally, the device further comprises an input disc and an output disc which are oppositely arranged, two crank shafts are inserted on the right-handed outer helical gear and the left-handed outer helical gear, and one end of each crank shaft is connected with the output disc; the other end of the crankshaft is connected to a first stage planetary gear train.

Optionally, the first-stage planetary gear train includes a sun gear shaft as an input and a planetary gear paired with the sun gear, the sun gear shaft is connected with the motor, and the planetary gear is inserted on the crank shaft and is in spline fit with the crank shaft.

Optionally, an output disc bearing is installed between the output disc and the housing to support the output disc.

Optionally, retainer rings are arranged on two sides of the planet wheel, and the planet wheel is axially limited by the retainer rings and a shaft shoulder of the crankshaft.

Optionally, an input end cover is fixed to the housing, the input end cover and the input disc are supported through an angular contact ball bearing, and the output disc and the housing are fixed through an angular contact ball bearing.

Optionally, the corresponding shaft section of the crankshaft for supporting the right-handed outer helical gear and the left-handed outer helical gear is an eccentric shaft section, and is correspondingly provided with an eccentric bearing, and is respectively used for supporting the right-handed outer helical gear and the left-handed outer helical gear, and the shaft section for supporting the rotation of the crankshaft is a non-eccentric shaft section and is provided with a crank bearing.

Optionally, deep groove ball bearings are installed at two ends of the sun gear shaft and used for supporting the sun gear shaft, and the deep groove ball bearings are axially positioned by a retaining shoulder of the input disc, a retaining shoulder of the input end cover and a shaft shoulder of the input shaft.

Optionally, the elastic element is a disc spring, and a gasket is arranged between the disc spring and the adjusting screw.

Optionally, a plurality of adjusting screws are uniformly distributed and arranged on the circumference of the shell corresponding to the disc spring.

The invention has the beneficial effects that:

1. the gap eliminating mechanism arranged in the second-stage small tooth difference gear train realizes the gap eliminating function through two pairs of inner meshing helical gears, the helical gears have high transmission contact ratio and good stability, and can reduce vibration during high-speed heavy load, thereby achieving the performance optimization of high precision and high bearing capacity.

2. In the transmission process, for the inner bevel gear ring, due to the existence of the axial force of the disc spring, the axial force generated by the inner bevel gear in the transmission process can be offset with the axial force applied by the disc spring, so that the harm caused by the axial force is reduced to a certain extent.

3. Because the two internal helical gears are integrated, the application of the gap eliminating force at the gap eliminating structure can push the two internal gears to move axially only by applying the gap eliminating force at one side of the internal gear, thereby realizing the gap adjustment under two working conditions of forward and reverse rotation by applying the axial force once.

4. One end of the adjusting screw is in contact with the disc spring, the other end of the adjusting screw is arranged on the outer side of the end cover, and the size of the axial force applied by the disc spring is controlled by rotating the adjusting screw. And aiming at the working condition of failure, the backlash eliminating forces with different sizes can be obtained. And the shell of the speed reducer does not need to be disassembled when the anti-backlash force is adjusted every time, and only the adjusting screw needs to be rotated outside the shell, so that the problem of precision reduction caused by assembly and disassembly is solved, and the use condition and precision of the speed reducer are improved.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Drawings

For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a cross-sectional view of a gap-adjustable helical gear small tooth difference precision reducer of the invention;

FIG. 2 is a schematic diagram of a backlash elimination principle of an inner helical gear pair;

fig. 3 is an analysis diagram of transmission stress of the internal bevel gear ring.

Reference numerals: the device comprises a box body 1, a sealing ring 2, an output end cover 3, an angular contact ball bearing 4, a hole clamp spring 5, an adjusting gasket 6, a crank bearing 7, a crank shaft 8, an eccentric bearing 9, a right-handed outer helical gear 10, a left-handed outer helical gear 11, an inner helical gear 12, a fixing screw 13, an adjusting screw 14, a gasket 15, a disc spring 16, a motor 17, a sun gear shaft 18, a deep groove ball bearing 19, a planet gear 20, a retainer ring 21, an input disc 22, an input end cover 23, a hole clamp spring 24 and a gasket 25.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.

Wherein the showings are for the purpose of illustrating the invention only and not for the purpose of limiting the same, and in which there is shown by way of illustration only and not in the drawings in which there is no intention to limit the invention thereto; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not an indication or suggestion that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes, and are not to be construed as limiting the present invention, and the specific meaning of the terms may be understood by those skilled in the art according to specific situations.

Referring to fig. 1 to 3, in the bevel gear reducer with adjustable clearance, an input end cover 23 is fixed at an end of a box body 1 through a fixing screw 13, and an output end cover 3 is fixed at an end of the box body 1 through a sealing ring 2, which together form a housing. A first-stage planetary gear train and a second-stage small tooth difference bevel gear train which is driven by the first-stage planetary gear train are arranged in the box body 1.

The second-stage small-tooth-difference helical gear train comprises two pairs of inner meshing helical gear pairs and clearance elimination mechanisms which are arranged side by side, wherein one pair of inner meshing helical gear pairs close to the left end consists of a right-handed outer helical gear 10 and a right-handed part of a clearance elimination inner helical gear ring 12 meshed with the right-handed outer helical gear, the other pair of inner meshing helical gear pairs consists of a left-handed outer helical gear 11 and a left-handed part of the clearance elimination inner helical gear ring 12 meshed with the left-handed outer helical gear, and the clearance elimination inner helical gear ring 12 is in sliding fit with the box body 1; the right-handed outer helical gear 10 and the left-handed outer helical gear 11 are connected on the two crank shafts 8 in a penetrating manner; the anti-backlash mechanism comprises two pairs of inner-meshing helical gear pairs which are arranged side by side and have opposite rotating directions and the same tooth number modulus, and an elastic element arranged on the right side of the inner-helical gear ring 12. The elastic element is a disc spring 16, the magnitude of the axial force applied to the internally-inclined gear ring 12 by the disc spring 16 is controlled by an adjusting screw 14, and a high-finish gasket 15 for reducing friction is arranged between the adjusting screw 14 and the disc spring 16.

The right-handed outer helical gear 10 and the left-handed outer helical gear 11 are sleeved on two crank shafts 8, one end of each crank shaft 8 is connected with the output disc 3 through a crank bearing 7, and the output disc 3 is connected with the shell 1 through an angular contact ball bearing 4; the other end of the crank shaft 8 is connected to an input disc 22 through a crank bearing 7, and the input disc 22 is connected to the sun gear shaft 18 through a deep groove ball bearing 19.

The first-stage planetary gear train comprises an input sun gear shaft 18 and planet gears 20 fixedly connected to the crank shaft 8 through splines, the two planet gears 20 are meshed with the sun gear shaft 18 in a matching mode, retainer rings 21 fixed to the crank shaft 8 are arranged on two sides of each planet gear 20 and used for axially positioning the planet gears 20, and the sun gear shaft 18 is connected with the motor 17.

The corresponding shaft section of the crank shaft 8 for passing through the right-handed outer helical gear 10 and the left-handed outer helical gear 11 is an eccentric shaft end, and is correspondingly provided with an eccentric bearing 9 for supporting the right-handed outer helical gear 10 and the left-handed outer helical gear 11. Accordingly, the right-hand external helical gear 10 and the left-hand external helical gear 11 are eccentrically arranged. The eccentric bearing 9 is axially restrained by a corresponding shoulder and washer 25 on the crankshaft 8.

Deep groove ball bearings 19 for supporting the input sun gear shaft 18 are respectively installed between the input sun gear shaft 18 and the input end cover 23 and the input disc 22. The deep groove ball bearing 19 is axially limited by a shaft shoulder of the input sun gear shaft 18, a blocking shoulder of the input end cover 23 and a blocking shoulder of the input disc 22.

Crank bearings 7 are mounted on crank shaft 8 and output disc 3 and input disc 22 to support crank shaft 8, output disc 3 and input disc 22. The crank bearing 7 at the left end is axially limited by a gasket 25 mounted on the crank shaft 8 and a hole-used clamp spring 5 mounted on the output disc 3, an adjusting gasket 6 is arranged between the hole-used clamp spring 5 and the crank bearing 7, and the crank bearing 7 at the right end is axially limited by the gasket 25 mounted on the crank shaft 8 and a blocking shoulder of the input disc 22.

Angular contact ball bearings 4 are mounted between the output disc 3 and the housing 1 and between the input disc 22 and the input end cover 23, the left end angular contact ball bearing 4 is used for supporting the housing 1, and the right end angular contact ball bearing 4 is used for supporting the input end cover 23. The left angular contact ball bearing 4 is axially limited by a shaft shoulder of the output disc 3 and a blocking shoulder of the shell 1, and the right angular contact ball bearing 4 is axially limited by a shaft shoulder of the input disc 22 and a blocking shoulder and a hole clamp spring 24 of the input end cover 23.

The anti-backlash principle of the transmission device is as follows: the disc spring 16 is controlled by the adjusting screw 14 to apply an axial force to the inner helical gear ring 12, so that the inner helical gear ring 12 axially moves, which is equivalent to that two inner helical gears in two pairs of inner helical gear pairs axially move in the same direction at the same time, when both sides of the tooth profile of the inner helical gear ring 12 and the tooth profile of the outer helical gear which is meshed with the inner helical gear pair have gaps, the single sides of the tooth profile parts of the inner helical gear ring 12 with the same tooth number modulus and the opposite spiral directions respectively cling to the tooth profile single side of the outer helical gear which is meshed with the inner helical gear ring in the process of axial movement. Therefore, two pairs of inner-meshing helical gear pairs are meshed, wherein the left tooth profile of one pair is meshed, and the right tooth profile of the other pair is meshed, so that backlash is eliminated, and return difference is reduced; similarly, when one side of the tooth profile of the inner gear ring 12 is in a gap with the tooth profile of the meshed outer helical gear (for example, the right-handed outer helical gear 10), the tooth profile part of the inner helical gear ring 12 directly drives the meshed outer helical gear (for example, the right-handed outer helical gear 10) to rotate through the meshed tooth profile at the side which is originally attached to the tooth profile part when the tooth profile part of the inner helical gear ring 12 axially moves. At this time, since the right-hand external helical gear 10 and the left-hand external helical gear 11 are sleeved on the two crank shafts 8, the left-hand external helical gear 11 rotates along with the right-hand external helical gear 10 until the tooth profiles on the other sides of the other pair of gears are attached tightly, thereby achieving the same effect. The specific principle analysis diagram is shown in a principle sketch of backlash elimination of the bevel gear pair in fig. 2.

During transmission, the tooth-shaped portion of the internally-skewed ring gear 12 generates an axial force, which is opposite to the direction of the axial force applied by the disc spring 16 regardless of whether the right-hand ring gear pair is engaged or the left-hand ring gear pair is engaged, as shown in fig. 3. Therefore, the structure of the gap eliminating mechanism can reduce the damage of the inner helical gear caused by axial force during working to a certain extent, and improves the transmission performance of the whole machine.

When the transmission device works, power is input through the sun gear shaft 18, the power is output to the second-stage small tooth difference gear transmission system through the transmission of the first-stage planetary gear system through the crank shaft 8, and the right-handed external helical gear 10 and the left-handed external helical gear 11 are driven to rotate while the crank shaft 8 rotates. Meanwhile, the crankshaft 8 transmits the rotation to the output disc 3 to complete torque output; meanwhile, the transmission precision of the transmission device is ensured by the gap eliminating effect of the disc spring 16, the inner helical gear ring 12, the right-handed outer helical gear 10 and the left-handed outer helical gear 11, the high contact ratio of the helical gear pair and the like.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.