1. The utility model provides a carry on light-duty steering wheel of harmonic speed reducer machine which characterized in that: the motor-driven harmonic reducer comprises a front shell (10) and a rear shell (1) which are mutually buckled, wherein a motor and a harmonic reducer are arranged in the front shell (10) and the rear shell (1); one end of a cam (4) of the harmonic speed reducer is a driven synchronous belt wheel, and the driven synchronous belt wheel is combined with a driving belt wheel (15) on a motor (14) through a synchronous belt (5); the other end of the cam (4) is coaxially connected with an elliptical cam, the elliptical cam and a flexible bearing (7) which is nested outside form a wave generator and are positioned in the inner wall of the flexible gear (9); the outer ring teeth of the flexible gear (9) and the inner ring teeth of the steel gear (8) are meshed or separated periodically in the rotation process of the wave generator; the flexible wheel (9), the steel wheel (8) and the cam (4) are all formed by injection molding of engineering plastics.

2. The light steering engine with the harmonic reducer as claimed in claim 1, wherein: the cam (4) is a two-stage step cam, the smaller step end is an elliptical cam, and a flexible bearing (7) is nested outside the elliptical cam; the periphery of the larger step end of the cam (4) is provided with a tooth surface to form a driven synchronous pulley, and the driven synchronous pulley is meshed with the synchronous belt (5).

3. The light steering engine with the harmonic reducer as claimed in claim 2, wherein: the top of one end of the cam (4) provided with the driven synchronous pulley is fixedly provided with a synchronous belt retainer ring (3), the inner space of one end of the cam (4) provided with the oval cam is provided with a balance bearing (6), and the inner ring of the balance bearing (6) is fixed on the output shaft (12).

4. The light steering engine with the harmonic reducer as claimed in claim 1, wherein: the output shaft (12) adopts a long shaft design, the flexible gear (9) is fixed on the outer wall of one end combined with the front shell (10), an output mounting flange is arranged on the outer side of the flexible gear (9), and the output mounting flange is flush with the end face of the front shell (10) on the periphery of the output shaft (12).

5. The light steering engine with the harmonic reducer as claimed in claim 1, wherein: a counter bore is formed in one end, facing the rear shell (1), of the output shaft (12), magnetic steel (16) is arranged in the counter bore in an interference fit mode, an auxiliary bearing (2) is mounted on the outer shaft of the counter bore, and the auxiliary bearing (2) is fixed between the output shaft (12) and the inner wall of a central hole of the output shaft (12) of the rear shell (1); and a position sensor (17) is also arranged on the rear shell (1) corresponding to the position magnetic steel (16).

6. The light steering engine with the harmonic reducer as claimed in claim 1, wherein: the steel wheel (8) is axially clamped on a step between the front shell (10) and the rear shell (1), and the bottom cover of the flexible wheel (9) is rigidly fixed with the output shaft (12); a supporting bearing (11) is arranged between the front shell (10) and the output shaft (12), and the supporting bearing (11) is installed with the front shell (10) in an interference fit mode and is located in the end face of the front shell (10) on the periphery of the output shaft (12).

7. The light steering engine with the harmonic reducer as claimed in claim 1, wherein: the flexible gear (9) and the steel gear (8) adopt C-shaped teeth.

8. The light steering engine with the harmonic reducer as claimed in claim 1, wherein: the steel wheel (8) and the cam (4) are formed by injection molding of carbon fiber with PPS +10% or more; the flexible gear (9) is formed by adding carbon fiber, PTFE or molybdenum disulfide into a base material by using one of materials such as POM, PA, PPS or PEEK and the like.

9. The light steering engine with the harmonic reducer as claimed in claim 1, wherein: the front shell (10) and the rear shell (1) are formed by injection molding of PPS or PC with more than 10% of carbon fiber or glass fiber.

Background

The traditional harmonic reducer has the advantages of compact structure, small volume, light weight, large bearing capacity, small back clearance, high transmission precision and the like, and is widely applied to the fields of industrial robots, aerospace and precision machine tools. The harmonic speed reducer comprises a steel wheel, a flexible wheel and a wave generator, wherein the wave generator with elliptic deformation is arranged in the flexible wheel with elasticity, and the wave generator rotates to force the flexible wheel tooth form and the steel wheel tooth form to be periodically meshed and separated, so that the effect of staggered tooth difference speed reduction is realized.

However, the conventional harmonic reducer has the following problems in the application of the steering engine:

1. the traditional harmonic reducer is generally made of metal materials, so that the quality of the product of the speed-reducing steering engine is higher.

2. In order to ensure the deformation of metal, the flexible gear of the harmonic reducer needs to have a certain length in the axial direction, so that the volume of the harmonic reducer is large, and the performance of the harmonic reducer is influenced.

3. The traditional harmonic reducer and the steering engine comprising the same consider the processing performance of metal, the shape design of a product is very limited, and the heat treatment process and the like are considered, so that the traditional harmonic reducer is not as flexible as an injection molding product.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the light steering engine for the harmonic speed reducer is light in weight, small in size and compact in space, the sealing performance and integrity of the steering engine are reasonably guaranteed, assembly and production are convenient, and reliability is high.

In order to solve the technical problems, the invention adopts the following technical scheme:

the utility model provides a carry on light-duty steering wheel of harmonic speed reducer machine which characterized in that: the motor-driven harmonic reducer comprises a front shell (10) and a rear shell (1) which are mutually buckled, wherein a motor and a harmonic reducer are arranged in the front shell (10) and the rear shell (1); one end of a cam (4) of the harmonic speed reducer is a driven synchronous belt wheel, and the driven synchronous belt wheel is combined with a driving belt wheel (15) on a motor (14) through a synchronous belt (5); the other end of the cam (4) is coaxially connected with an elliptical cam, the elliptical cam and a flexible bearing (7) which is nested outside form a wave generator and are positioned in the inner wall of the flexible gear (9); the outer ring teeth of the flexible gear (9) and the inner ring teeth of the steel gear (8) are meshed or separated periodically in the rotation process of the wave generator; the flexible wheel (9), the steel wheel (8) and the cam (4) are all formed by injection molding of engineering plastics.

Furthermore, the cam (4) is a two-stage step cam, the smaller step end is an elliptical cam, and a flexible bearing (7) is nested outside the elliptical cam; the periphery of the larger step end of the cam (4) is provided with a tooth surface to form a driven synchronous pulley, and the driven synchronous pulley is meshed with the synchronous belt (5).

Furthermore, a synchronous belt retainer ring (3) is fixed at the top of one end, provided with a driven synchronous pulley, of the cam (4), a balance bearing (6) is installed in an inner space, provided with one end of the oval cam, of the cam (4), and an inner ring of the balance bearing (6) is fixed on the output shaft (12).

Furthermore, the output shaft (12) adopts a long shaft design, the flexible gear (9) is fixed on the outer wall of one end combined with the front shell (10), the outer side of the flexible gear (9) is provided with an output mounting flange, and the output mounting flange is flush with the end face of the front shell (10) on the periphery of the output shaft (12).

Furthermore, a counter bore is formed in one end, facing the rear shell (1), of the output shaft (12), magnetic steel (16) is arranged in the counter bore in an interference fit mode, an auxiliary bearing (2) is installed on the outer shaft of the counter bore, and the auxiliary bearing (2) is fixed between the output shaft (12) and the inner wall of the central hole of the output shaft (12) of the rear shell (1); and a position sensor (17) is also arranged on the rear shell (1) corresponding to the position magnetic steel (16).

Further, the steel wheel (8) is axially clamped on a step between the front shell (10) and the rear shell (1), and the bottom cover of the flexible wheel (9) and the output shaft (12) are rigidly fixed together; a supporting bearing (11) is arranged between the front shell (10) and the output shaft (12), and the supporting bearing (11) is installed with the front shell (10) in an interference fit mode and is located in the end face of the front shell (10) on the periphery of the output shaft (12).

Furthermore, the tooth shapes of the flexible gear (9) and the steel gear (8) are C-shaped teeth.

Further, the steel wheel (8) and the cam (4) are formed by injection molding of carbon fiber with PPS +10% or more; the flexible gear (9) is formed by adding carbon fiber, PTFE or molybdenum disulfide into a base material by using one of materials such as POM, PA, PPS or PEEK and the like.

Furthermore, the front shell (10) and the rear shell (1) are formed by injection molding of PPS or PC with more than 10% of carbon fiber or glass fiber.

Therefore, the light steering engine provided by the invention is loaded with a special plastic harmonic speed reducing mechanism, the flexible gear, the steel gear and the cam of the plastic harmonic speed reducing mechanism are all formed by injection molding of special engineering plastics, and the design of the tooth form C tooth form is adopted to ensure the transmission torque and rigidity of the plastic speed reducer. The driving motor of the light steering engine drives the synchronous belt through a driving synchronous belt pulley arranged on an output shaft of the motor to drive a driven synchronous belt pulley integrated with the cam to rotate, the cam rotates to promote the wave to work, and the harmonic reducer operates. And the position sensor senses the rotation angle of the output shaft and controls a position closed loop and a speed closed loop of the light steering engine. The light steering engine has the advantages of compact mechanism, small volume, small back clearance, high transmission precision and large reduction ratio.

Compared with the prior harmonic speed reducing mechanism and the light steering engine thereof, the invention has the following beneficial effects:

the assembly is convenient, a plurality of connecting pieces such as screws and the like can be omitted, and the weight is further reduced.

The structure of the invention has a unique assembly mode, reduces the assembly difficulty, realizes the fool-proof and mistake-proof effects and is convenient to manufacture.

The harmonic reducer ware includes that the casing all is non-metal material, and the quality of speed reduction steering wheel product is littleer.

The flexible gear of the harmonic reducer is made of nonmetal materials, the deformation of metal is not considered, and the length of the flexible gear in the axial direction is controlled to be flat and is greatly smaller than that of the flexible gear made of metal materials.

Considering the non-metallic properties of materials such as the shell, the steel wheel, the cam and the like, the shape design and the process of the product are more flexible to the metal processing process, and the processing performance of the product is superior to that of the traditional metal harmonic reducer and the steering engine thereof.

Drawings

Fig. 1 is a schematic structural view (perspective view) of a light steering engine equipped with a harmonic reducer according to the present invention.

Fig. 2 is a schematic structural diagram of a transmission part of a light steering engine with a harmonic reducer (with a rear shell 1 removed).

Fig. 3 is a schematic diagram of the internal structure of a light steering engine with a harmonic reducer according to the present invention.

The drawings in fig. 1-3 are illustrated as follows: 1. a rear housing; 2. an auxiliary bearing; 3. a synchronous belt retainer ring; 4. a cam; 5. a synchronous belt; 6. a balance bearing; 7. a compliant bearing; 8. a steel wheel; 9. a flexible gear; 10. a front housing; 11. a support bearing; 12. an output shaft; 13. a flexspline pad; 14. a motor; 15. a driving pulley; 16. position magnetic steel; 17. a position sensor.

The specific implementation mode is as follows:

in order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In the attached drawings 1-3, the light steering engine carrying the harmonic reducer comprises a front shell 10 and a rear shell 1 which are buckled up and down, and the front shell 10 and the rear shell 1 are assembled into an integrated light steering engine through self-tapping screws, so that the sealing property and the integrity of the steering engine are ensured, the assembly and the production are convenient, and the reliability is high.

The motor 14 and the harmonic speed reducer arranged in parallel with the shaft of the motor 14 are arranged in the two shells; the harmonic reducer comprises a flexible gear 9, a steel gear 8 and a wave generator which is arranged in the flexible gear 9 in an inner-outer sleeved mode and comprises a cam 4. The motor 14 and the harmonic speed reducing mechanism are arranged in parallel, so that the space is compact and the arrangement is reasonable.

The outer ring of the flexible gear 9 and the inner ring of the steel gear 8 are engaged and separated periodically, so that the effect of staggered tooth difference speed reduction is realized.

Inside the flexspline 9, a wave generator including the cam 4 is provided. The cam 4 is a two-stage step cam, the smaller step end is an elliptical cam, the flexible bearing 7 is nested outside the elliptical cam, the flexible bearing 7 is arranged on the inner ring of the flexible gear 9, and the inner ring of the flexible gear 9 is provided with a limiting check ring which can control the axial position of the flexible bearing 7. The periphery of the larger step end of the cam 4 is provided with a tooth surface to form a driven synchronous belt wheel, and the driven synchronous belt wheel is meshed with the synchronous belt 5; the end of the cam 4 provided with the driven belt wheel is fixed with a synchronous belt retainer ring 3 through a self-tapping screw, and can limit the axial movement of the synchronous belt 5.

The flexible bearing 7 is arranged on the inner ring of the flexible gear 9 and is positioned between the flexible gear 9 and the outer wall of the oval cam, and the inner ring of the flexible gear 9 is provided with a limiting check ring which can control the axial position of the flexible bearing 7. The bottom cover of the flexspline 9 and the output shaft 12 are rigidly fixed together by self-tapping screws. The steel wheel 8 is provided with a limiting groove which is tightly matched, clamped and fixed with the positioning hole and the positioning rib of the front shell 10, and the supporting bearing 11 is installed in interference fit with the front shell 10.

A balance bearing 6 is arranged between the inner shaft hole of the oval cam and the output shaft 12 therein, and the balance bearing 6 is positioned inside the corresponding cam 4. The inner ring of the balance bearing 6 is fixed on an output shaft 12, and the output shaft 12 and the output shaft of the motor 14 are arranged in parallel.

An output shaft 12 penetrates through an inner center hole of the front shell 10, a support bearing 11 is arranged between the front shell 10 and the output shaft 12 for axial limiting, the output shaft 12 adopts a long shaft design, and an output mounting flange is arranged at one end, combined with the front shell 10, of the output shaft 12; the other end of the rear shell is provided with a counter bore, magnetic steel 16 is arranged in the counter bore in an interference fit mode, an auxiliary bearing 2 is arranged on an outer shaft of the counter bore, the auxiliary bearing 2 is correspondingly arranged between the side wall of the central hole of the rear shell 1 and the outer shaft of the counter bore, and the side wall of the central hole of the rear shell 1 is provided with an installation hole of the auxiliary bearing 2; the rear housing 1 is provided with a fixing hole at a position corresponding to the output shaft for fixing the position sensor 17.

The motor 14 is installed on the motor mount pad of front casing 10, and interference fit has driving pulley 15 on the output shaft of motor 14, and motor 14 drives hold-in range 5 through driving pulley 15, and the driven pulley on the drive cam 4 rotates. The driving pulley 15 is enclosed in the rear housing 1 and spaced apart from the inner wall of the top of the rear housing 1.

In order to realize light weight, the flexible gear, the steel gear and the cam of the harmonic speed reducing mechanism are all formed by injection molding of special engineering plastics, and in order to ensure the transmission torque and rigidity of the plastic speed reducer, the tooth shapes of the flexible gear and the steel gear are all designed by C tooth shapes. The tooth shape of the steel wheel is formed by the motion envelope of the tooth shape of the flexible wheel; the tooth height of the C tooth profile is 30% higher than that of an involute tooth profile or an arc tooth profile ruler; the meshing proportion of the harmonic tooth profile of the C tooth profile is 50 percent higher than that of an involute tooth profile or an arc tooth profile.

The tooth top arc radius of the C tooth profile is smaller than that of the involute tooth profile or the arc tooth profile, and the tooth root arc radius is larger than that of the involute tooth profile or the arc tooth profile.

The cam profile of the wave generator related by the invention adopts an elliptical profile, the major axis and the minor axis of the ellipse are determined according to the speed ratio and the gear modulus of the harmonic speed reducer, and the polar coordinate equation of the elliptical curve isWherein a and b are the lengths of the major and minor axes of the elliptic curve, rho_bIs a polar shaft, and is characterized in that,is a polar angle.

The flexible gear C tooth shape determining process is as follows:

firstly, the flexible gear tooth profile is set to adopt a circular arc tooth profile, and the polar coordinate equation of the tooth profile isIn the formula (R)₀，θ₀) Is a circle with a center pointIn the notation, R is the radius of the circle. By cam elliptic profile lineThe evolute S can be determined from the differential geometry, whereinThe evolute being a cam profileEnvelope of the normal family, through coordinate transformation, the polar coordinate equation of the tooth profile of the flexible gear tooth profileAnd evoluteAnd (5) approximating the fitting, and finally determining the C-shaped tooth form of the flexible gear by considering the diameter of the addendum circle, the diameter of the dedendum circle and the diameter of the reference circle of the flexible gear. And obtaining the flexible gear tooth-shaped envelope by a finite element analysis method according to the rotation rule of the wave generator and the deformation condition of the flexible gear C tooth-shaped, and drawing the steel gear tooth-shaped.

Further, the engineering plastic substrate can be at least one of nylon, POM, PAI and PEEK, or one of carbon fiber, glass fiber, graphite, PTFE and molybdenum disulfide is added on the substrate.

Further, the steel wheel 8 and the cam 4 are formed by injection molding of carbon fiber with PPS +10% or more; the flexible gear 9 is formed by injection molding by adding carbon fiber, PTFE or molybdenum disulfide into base materials such as POM, PA, PPS or PEEK.

The front shell 10 and the rear shell 1 are formed by injection molding of PPS or PC with more than 10% of carbon fiber or glass fiber.

Therefore, the motor 14 drives the driving belt wheel 15, the driven synchronous belt wheel on the cam 4 is driven by the synchronous belt 5, the flexible bearing 7 is arranged on the upper edge of the cam 4 to form a wave generator, the wave generator is arranged in the flexible wheel 9 with elasticity, and the wave generator rotates to force the tooth form of the flexible wheel 9 and the tooth form of the steel wheel 8 to be meshed and separated periodically, so that the effect of staggered tooth difference speed reduction is realized. The flexible gear 9 and the output shaft 12 are fixed together, the output shaft 12 adopts a coaxial design, the tail end of the output shaft 12 is provided with position magnetic steel 16, and the position magnetic steel and the position sensor 17 form a position and speed control closed loop of the light steering engine.

It should be noted that, according to the implementation requirement, each step/component described in the present application can be divided into more steps/components, and two or more steps/components or partial operations of the steps/components can be combined into new steps/components to achieve the purpose of the present invention.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.