Harmonic reducer flexible gear and harmonic reducer

Abstract

The utility model discloses a harmonic reducer flexible gear and a harmonic reducer, the harmonic reducer flexible gear comprises a cylindrical main body part made of a first material, and the cylindrical main body part is subjected to radial flexible deformation under external force and is provided with an opening end used for installing a wave generator assembly of the harmonic reducer; a flexible gear outer ring gear formed of a second material, joined to the outer peripheral surface of the open end side of the cylindrical body portion in the circumferential direction, and radially and flexibly deformed in synchronization with the cylindrical body portion; the axial length of the cylindrical main body part is greater than that of the flexible gear outer gear ring, so that heat dissipation can be conveniently carried out through the part, exceeding the flexible gear outer gear ring, of the cylindrical main body part; the rigidity of the cylindrical main body part is greater than that of the flexible gear outer gear ring, so that the cylindrical main body part can support the flexible gear outer gear ring. The harmonic reducer comprises a wave generator, a flexible bearing, the flexible gear and a rigid gear. When the flexible gear works, heat generated by meshing and collision of the outer gear ring of the flexible gear can be guided out by the cylindrical main body part, so that heat accumulation is avoided, and the service life of the flexible gear is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of harmonic reducer, especially to a harmonic reducer flexspline and harmonic reducer. BACKGROUND

[0002] Harmonic reducer is widely used in robot, aerospace, instrument, precision optical equipment and medical machinery, and the flexspline is a core component, the structural feature of the flexspline is thin wall, and the flexspline bears alternating stress generated by deformation during operation, the flexspline is the most complex component in harmonic reducer and is the most likely failure component in harmonic reducer, therefore, the manufacturing process of the flexspline is very important.

[0003] At present, the machining process of metal flexspline and the injection molding process of full plastic flexspline are mainly used due to strength and precision problems, the machining process of metal flexspline is very complex, the cost is high, and the production efficiency is low, the production efficiency of full plastic flexspline is high, and the toughness is good, but the strength and rigidity of the flexspline tooth root are poor, the strength of the ring part of the plastic flexspline is poor, and the use requirement of large load torque cannot be met, in addition, the plastic material has the problems of poor heat conduction and heat dissipation, which will cause heat accumulation, temperature rise of the plastic flexspline, and greatly reduce the strength of the flexspline tooth and the service life of the plastic flexspline. UTILITY MODEL CONTENT

[0004] In order to overcome the defects in the prior art, the utility model provides a harmonic reducer flexspline and harmonic reducer, which has the advantages of good heat dissipation, large rigidity and large strength.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0006] A harmonic reducer flexspline, comprising:

[0007] A cylindrical main body part formed of a first material, which is radially flexibly deformed by external force, and has an open end for mounting a wave generator assembly of the harmonic reducer;

[0008] A flexspline outer gear ring formed of a second material, which is joined on the outer peripheral surface of the open end side of the cylindrical main body part in the circumferential direction, and is synchronously radially flexibly deformed with the cylindrical main body part;

[0009] Wherein, the axial length of the cylindrical main body part is greater than the axial length of the flexspline outer gear ring, so as to facilitate heat dissipation through the part of the cylindrical main body part beyond the flexspline outer gear ring, and the rigidity of the cylindrical main body part is greater than the rigidity of the flexspline outer gear ring, so that the cylindrical main body part supports the flexspline outer gear ring.

[0010] By adopting the technical scheme, the cylindrical body part is used as a support frame, and the flexible gear outer gear ring is covered thereon, so that the flexible gear has a full-plastic structure and flexibility, and the axial length of the cylindrical body part is greater than that of the flexible gear outer gear ring, so that heat generated by the flexible gear outer gear ring during engagement and collision is absorbed by the cylindrical body part and is quickly dissipated through the part of the cylindrical body part not covered with the flexible gear outer gear ring, thereby avoiding heat accumulation and increasing the service life of the flexible gear.

[0011] Optionally, the outer circumferential surface of the open end side of the cylindrical body part has a skeleton outer gear ring, and the flexible gear outer gear ring is engaged on the skeleton outer gear ring.

[0012] By adopting the technical scheme, in order to ensure normal operation of the flexible gear, the tensile stress caused by the load torque and the flexible deformation stress caused by the wave generator need to be comprehensively considered, so the thickness of the cylindrical body part cannot be too large, and on this basis, the skeleton outer gear ring increases the support of the flexible gear outer gear ring, thereby improving the tooth root fatigue strength of the flexible gear outer gear ring, and the skeleton outer gear ring increases the connection area of the flexible gear outer gear ring and the cylindrical body part, thereby effectively improving the connection strength of the flexible gear outer gear ring, especially the circumferential connection strength.

[0013] Optionally, the skeleton outer gear ring comprises a plurality of support teeth, and the flexible gear outer gear ring comprises a plurality of flexible gear teeth, the support teeth correspond to the flexible gear teeth one by one and are embedded in the flexible gear teeth.

[0014] By adopting the technical scheme, the support teeth of the skeleton outer gear ring are embedded in the flexible gear teeth of the flexible gear outer gear ring one by one, so that heat generated by the flexible gear outer gear ring during engagement and collision is more quickly absorbed by the cylindrical body part, and the gear teeth of the flexible gear are actually composed of the support teeth of the skeleton outer gear ring and the flexible gear teeth of the flexible gear outer gear ring, so that the tooth root strength is obviously increased compared with the gear of the full-plastic structure flexible gear; in addition, since the support teeth of the skeleton outer gear ring are embedded in the flexible gear teeth of the flexible gear outer gear ring one by one, the wall thickness of the flexible gear outer gear ring can be uniform, and heat will not be concentrated in a certain place to reduce the strength of the flexible gear teeth.

[0015] Optionally, the addendum circle of the skeleton outer gear ring is located between the dedendum circle and the reference circle of the flexible gear outer gear ring.

[0016] By adopting the technical scheme, the gear teeth of the skeleton outer gear ring are only located at the dedendum of the flexible gear outer gear ring, so that the tooth root strength is increased without making the gear strength of the flexible gear too large to cause impact when the rigid gear engages, and the radial height of the skeleton outer gear ring is not too large to affect the flexible deformation of the flexible gear.

[0017] Optionally, the flexible gear outer ring has a uniform wall thickness of 0.1mm-0.5mm.

[0018] By adopting the above technical scheme, the flexible gear outer ring has a uniform wall thickness of 0.1mm-0.5mm, which is beneficial to heat dissipation, and meanwhile, the heat is not too concentrated in a certain place, thereby affecting the strength of the flexible gear outer ring.

[0019] Optionally, an outer circumferential surface of the open end side of the cylindrical main body part forms a radially outwardly protruding annular boss, the flexible gear outer ring is engaged to the outer circumferential surface of the annular boss, and axial two ends of the flexible gear outer ring radially extend inwardly to form a first retainer and a second retainer; the first retainer and the second retainer are respectively stopped at axial two sides of the annular boss.

[0020] By adopting the above technical scheme, the cooperation of the first retainer, the second retainer and the annular boss increases the connection area of the flexible gear outer ring and the cylindrical main body part, and in addition, the first retainer and the second retainer can bear axial force, thereby making the connection of the flexible gear outer ring and the cylindrical main body part more firm.

[0021] Optionally, an output connecting plate is arranged at one end of the cylindrical main body part away from the open end.

[0022] By adopting the above technical scheme, the output connecting plate makes the strength of the cylindrical main body part large, and can meet the use requirement of large load torque.

[0023] Optionally, the cylindrical main body part is a metal framework, and the flexible gear outer ring is a plastic outer ring, and the flexible gear outer ring is tightly engaged to the outer circumferential surface of the open end of the cylindrical main body part through injection molding.

[0024] By adopting the above technical scheme, the processing is performed in the injection molding mode, and meanwhile, the connection of the flexible gear outer ring and the cylindrical main body part is more stable.

[0025] Optionally, the cylindrical main body part is connected to the wave generator assembly through an inner circumferential surface of the open end side thereof.

[0026] By adopting the above technical scheme, heat generated by engagement and collision of the flexible gear outer ring during work can be transmitted to the wave generator assembly, thereby further improving the heat dissipation of the flexible gear outer ring.

[0027] A harmonic reducer includes a wave generator assembly and a rigid gear; the rigid gear has a rigid inner ring; the wave generator assembly includes a wave generator; the wave generator assembly further includes a flexible bearing; the harmonic reducer further includes the flexible gear mentioned above; the flexible bearing is installed between the wave generator and the open end of the cylindrical main body part; the flexible gear outer ring is radially flexibly deformed due to rotation of the wave generator, thereby forming partial engagement with the rigid inner ring.

[0028] By adopting the technical scheme, the harmonic reducer has large strength, fast heat dissipation and long service life, can meet large load torque, the flexible bearing can adapt to deformation of the flexspline, friction between the wave generator and the flexspline is smaller, operation is smoother, and wear is smaller. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a structural schematic view of embodiment one of the utility model.

[0030] Figure 2 is an exploded structural schematic view of embodiment one of the utility model.

[0031] Figure 3 is a structural schematic view of the flexspline of the flexspline partial section of embodiment one of the utility model.

[0032] Figure 4 is a structural schematic view of the section of the flexspline of embodiment one of the utility model.

[0033] Figure 5 is a structural schematic view of the flexspline of embodiment one of the utility model. Figure 4 is a structural schematic view of the partial enlargement of A.

[0034] Figure 6 is a structural schematic view of the flexspline of embodiment one of the utility model.

[0035] Figure 7 is a structural schematic view of the section of the flexspline of embodiment one of the utility model.

[0036] Figure 8 is a structural schematic view of the flexspline of embodiment one of the utility model. Figure 7 is a structural schematic view of the partial enlargement of B.

[0037] BRIEF DESCRIPTION OF DRAWINGS

[0038] 10, wave generator; 11, oval part;

[0039] 20, flexible bearing; 21, inner ring; 22, outer ring;

[0040] 30, flexspline; 31, cylindrical main body part; 310, open end; 311, skeleton outer gear ring; 3111, first tooth inclined surface; 3112, first tooth top surface; 312, output connecting plate; 313, outer peripheral surface; 314, extension part; 315, inner peripheral surface; 316, tooth top circle; 32, flexspline outer gear ring; 321, first retainer ring; 322, flexspline tooth; 3221, second tooth inclined surface; 3222, second tooth top surface; 323, second retainer ring; 324, tooth root circle; 325, division circle; 40, rigid gear; 41, rigid support ring; 42, rigid inner gear ring. DETAILED DESCRIPTION

[0041] The application will be further described below in conjunction with the accompanying drawings Figures 1-8 The application will be further described below in conjunction with the accompanying drawings

[0042] Embodiment one: a harmonic reducer is disclosed, referring to Figure 1 and Figure 2 , including a wave generator assembly, a flexspline 30 and a rigid gear 40; the wave generator assembly includes a wave generator 10 and a flexible bearing 20; the flexible bearing 20 is installed between the wave generator 10 and the flexspline 30; the inner ring 21 of the flexible bearing 20 is interference fitted with the elliptical part 11 of the wave generator 10, and the outer ring 22 is interference fitted with the flexspline 30; the rigid gear 40 includes a rigid support ring 41 and a rigid inner ring gear 42 coaxially fixed in the rigid support ring 41; the flexspline outer ring gear 32 is radially flexibly deformed due to the rotation of the wave generator 10, so as to form partial meshing with the rigid inner ring gear 42.

[0043] Referring to Figure 1 and Figure 2 , during the rotation of the wave generator 10, on the major axis of the elliptical part 11 of the wave generator 10, the teeth of the flexspline 30 are completely meshed with the teeth of the rigid inner ring gear 42 of the rigid gear 40; while on the minor axis of the elliptical part 11 of the wave generator 10, the teeth of the flexspline 30 are completely disengaged from the teeth of the rigid inner ring gear 42 of the rigid gear 40. With the rotation of the wave generator 10, the shape of the flexspline 30 is always close to an elliptical shape, so as to realize the continuous meshing and disengaging of the flexspline 30 and the rigid inner ring gear 42 of the rigid gear 40. During the rotation of the wave generator 10, when one tooth of the flexspline 30 is meshed with one tooth of the rigid inner ring gear 42 of the rigid gear 40 and is again meshed with this tooth on the rigid inner ring gear 42 of the rigid gear 40, the flexspline 30 rotates one revolution, while the wave generator 10 rotates many revolutions at this time, so as to play a role of speed reduction. The ratio of the number of revolutions of the wave generator 10 to the number of revolutions of the flexspline 30 is the speed reduction ratio of the harmonic gear reducer.

[0044] Referring to Figures 3-8, the flexspline 30 comprises a cylindrical body part 31 formed by a first material and a flexspline outer ring gear 32 formed by a second material; for the convenience of subsequent description, the teeth of the flexspline outer ring gear 32 are referred to as flexspline teeth 322; the cylindrical body part 31 is connected to external transmission components as the output end of the harmonic reducer; the cylindrical body part 31 is in a cylindrical shape and has an open end 310 at one axial end for interference fit with the outer ring 22 of the flexspline bearing 20 and an output connecting plate 312 connected at the other end; the flexspline outer ring gear 32 is joined on the outer circumferential surface 313 of the open end side of the cylindrical body part 31 along the circumferential direction; the inner circumferential surface 315 of the open end side of the cylindrical body part 31 is connected with the outer ring 22 of the flexspline bearing 20; the rigidity of the cylindrical body part 31 is greater than that of the flexspline outer ring gear 32, and the cylindrical body part 31 plays a supporting role for the flexspline outer ring gear 32; the axial length of the cylindrical body part 31 is greater than that of the flexspline outer ring gear 32; in this way, when the flexspline outer ring gear 32 is in meshing contact with the rigid inner ring gear 42, the heat generated will be absorbed by the cylindrical body part 31 and dissipated in the extension part 314 of the cylindrical body part 31 where the flexspline outer ring gear 32 is not joined, so that the accumulation of heat does not cause the temperature of the flexspline outer ring gear 32 to rise, thereby greatly reducing the strength of the teeth of the flexspline 30 and increasing the service life of the flexspline 30.

[0045] The shape of the cylindrical body part 31 can be cup-shaped, hat-shaped, or bell-shaped, i.e., open at one end and closed at the other end, so as to have greater strength and meet the requirements of large load torque.

[0046] Reference Figures 3-5 And Figure 8 In order to improve the strength of the tooth base of the flexspline teeth 322 of the flexspline outer ring gear 32, the outer circumferential surface 313 of the open end side of the cylindrical body part 31 has a skeleton outer ring gear 311, and the flexspline outer ring gear 32 is joined on the skeleton outer ring gear 311; for the convenience of subsequent description, the teeth of the skeleton outer ring gear 311 are referred to as support teeth 317. In order to ensure normal operation of the flexspline, the tensile stress caused by the load torque and the flexible deformation stress caused by the wave generator need to be considered comprehensively, so the thickness of the cylindrical body part 31 cannot be too large; on this basis, the skeleton outer ring gear 311 increases the support of the flexspline outer ring gear 32, thereby improving the fatigue strength of the tooth base of the flexspline outer ring gear 32; at the same time, the skeleton outer ring gear 311 increases the connection area between the flexspline outer ring gear 32 and the cylindrical body part 31, thereby effectively improving the connection strength of the flexspline outer ring gear 32, especially the circumferential connection strength.

[0047] Reference Figure 4 And Figure 5Wherein in order to further improve the tooth bottom strength of the flexspline tooth 322, the support tooth 317 corresponds to the flexspline tooth 322 one by one and is embedded into the flexspline tooth 322; so that the heat generated by the meshing collision of the flexspline outer gear ring 32 is absorbed by the cylindrical body part 31 faster, and the gear tooth of the flexspline is actually composed of the support tooth 317 and the flexspline tooth 322, so that the tooth bottom strength is obviously increased compared with the gear of the full plastic structure flexspline. In order to further improve the heat dissipation of the flexspline outer gear ring 32, the support tooth 317 has two first tooth slopes 3111 and a first tooth top surface 3112, the flexspline tooth 322 has two second tooth slopes 3221 and a second tooth top surface 3222; the second tooth top surface 3222 is parallel to the first tooth top surface 3112; the second tooth top surface 3222 is arranged in parallel with the first tooth slope 3111 on the corresponding side; the interval between the second tooth top surface 3222 and the first tooth top surface 3112 is equal to the interval between the second tooth top surface 3222 and the first tooth slope 3111 on the corresponding side, so that the flexspline outer gear ring 32 has a uniform wall thickness, thereby improving the heat dissipation of the flexspline outer gear ring 32; considering the working scene of the flexspline, the wall thickness of the flexspline outer gear ring 32 is best 0.1mm-0.5mm.

[0048] Reference Figure 4 And Figure 5 , in addition, in order to avoid the thickness of the cylindrical body part 31 affecting the working of the flexspline, the addendum circle 316 of the framework outer gear ring 311 is located between the dedendum circle 324 and the reference circle 325 of the flexspline outer gear ring 32, so that the support tooth 317 is only located at the dedendum of the flexspline tooth 322, while increasing the tooth bottom strength, it will not make the gear tooth strength of the flexspline too large, avoid causing impact when meshing with the rigid gear 40, in addition, it will not make the radial height of the framework outer gear ring 311 too large, thereby affecting the flexible deformation of the flexspline.

[0049] Reference Figure 3 , Figure 6 And Figure 7 , the axial both ends of the flexspline outer gear ring 32 extend radially inward to form a first retainer 321 and a second retainer 323; the first retainer 321 and the second retainer 323 are respectively stopped on the axial both sides of the framework outer gear ring 311; so that while ensuring the toughness of the flexspline 30, the first retainer 321 and the second retainer 323 increase the connection area with the cylindrical body part 31, thereby increasing the connection strength of the flexspline outer gear ring 32 and the cylindrical body part 31, in addition, the existence of the first retainer 321 and the second retainer 323 makes the flexspline outer gear ring 32 still can maintain the connection stability of the flexspline outer gear ring 32 and the cylindrical body part 31 under the condition of bearing a certain axial force.

[0050] The first material constituting the cylindrical body part 31 is metal, so the cylindrical body part 31 is a metal skeleton. Of course, the first material can also be an amorphous alloy material or other material that can withstand high-frequency alternating stress and has high shear fatigue strength. The second material constituting the flexspline outer gear ring 32 is plastic, so the flexspline outer gear ring 32 is a plastic outer gear ring. In actual production, the first material is an alloy structural steel, and the second material is PEI.

[0051] The cylindrical body part 31 is formed by a cold extrusion process, and the process steps are: blanking-normalizing / spheroidizing annealing-multiple cold extrusion-heat treatment-finishing. Of course, the cylindrical body part 31 can also be manufactured by machining, stretching, or die forming process of cold forging.

[0052] The flexspline outer gear ring 32 is formed by an injection molding process, and the specific process is as follows:

[0053] First step, raw material pretreatment: the PEI material required for the flexspline outer gear ring 32 is sent into the dehumidifying dryer for drying, the drying temperature is set to 150°C, and the drying time is 4-6h. After heating is completed, it is transferred to the injection molding machine;

[0054] Second step, injection molding: hot runner mold is used, wherein the front section temperature of the hot runner is set to 125°C, the rear section temperature is set to 150°C, the temperature from the barrel to the nozzle is set to 375°C, 380°C, 375°C, 370°C, and 355°C respectively, to ensure that the fluid plastic still has good fluidity when entering the mold cavity; after the open end side of the cylindrical body part 31 is placed into the injection mold, the injection mold is closed, the injection pressure of the injection molding machine is set to 135 par, and the injection speed is set to 60mm / s. The fluid plastic enters the mold cavity through the nozzle and covers the skeleton outer gear ring 311 of the cylindrical body part 31 to form the flexspline outer gear ring 32, the pressure is maintained for 20 seconds in the first pressure maintaining section, the pressure maintaining pressure is set to 30 par, the pressure is maintained for 15 seconds in the second pressure maintaining section, the pressure maintaining pressure is set to 15 par, the mold opening speed is controlled at 15mm / s, and the ejection speed is controlled at 15mm / s. Subsequently, the flexspline 30 is obtained;

[0055] Third step, injection stress relief treatment: the flexspline 30 obtained in the second step is placed in a high-temperature box at 120°C for 3 hours to obtain the flexspline 30 for use.

[0056] Example two: the difference between example two and example one is that the outer circumferential surface of the open end side of the cylindrical body part 31 forms a radially outwardly protruding annular boss, and the flexspline outer gear ring 32 is joined to the outer circumferential surface of the annular boss; the annular boss can provide certain support to the flexspline outer gear ring 32, thereby increasing the tooth bottom strength of the flexspline outer gear ring 32, but the annular boss does not have the support strength provided by the skeleton outer gear ring 311.

[0057] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, so that: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A flexible pulley for a harmonic reducer, characterized by: include: a cylindrical main body formed of a first material, which is radially flexible and deformable under external force, and has an open end for mounting a wave generator assembly of the harmonic reducer; The flexible spline outer gear ring formed of the second material is circumferentially engaged with the outer peripheral surface of the open end side of the cylindrical main body portion and undergoes radial flexible deformation synchronously with the cylindrical main body portion; Among them, the axial length of the cylindrical main body is greater than the axial length of the flexible spline outer ring, which facilitates heat dissipation through the portion of the cylindrical main body that exceeds the flexible spline outer ring; the stiffness of the cylindrical main body is greater than the stiffness of the flexible spline outer ring, so that the cylindrical main body supports the flexible spline outer ring.

2. The flexible spline of a harmonic reducer according to claim 1, characterized in that: The outer peripheral surface of the cylindrical main body on the opening end side has a skeleton outer ring gear, and the flexspline outer ring gear is joined to the skeleton outer ring gear.

3. The flexible spline of a harmonic reducer according to claim 2, characterized in that: The skeleton outer gear ring includes a plurality of supporting teeth, and the flexspline outer gear ring includes a plurality of flexspline teeth. The supporting teeth correspond to the flexspline teeth one by one and are embedded in the flexspline teeth.

4. The flexible spline of a harmonic reducer according to claim 3, characterized in that: The tooth top circle of the skeleton outer gear ring is located between the tooth root circle and the pitch circle of the flexible spline outer gear ring.

5. The flexible spline of a harmonic speed reducer according to claim 1, characterized in that: The flexible spline outer gear ring has a uniform wall thickness of 0.1 mm to 0.5 mm.

6. The flexible spline of a harmonic speed reducer according to claim 1, characterized in that: The outer peripheral surface of the open end side of the cylindrical main body forms an annular boss protruding radially outward, the flexible spline outer gear ring is engaged with the outer peripheral surface of the annular boss, and the axial ends of the flexible spline outer gear ring extend radially inward to form a first retaining ring and a second retaining ring; the first retaining ring and the second retaining ring are respectively stopped on both axial sides of the annular boss.

7. The flexible spline of a harmonic speed reducer according to claim 1, characterized in that: An output connecting plate is provided at one end of the cylindrical main body away from the opening end.

8. The flexible spline of a harmonic speed reducer according to claim 1, characterized in that: The cylindrical main body is a metal frame, the flexspline outer gear is a plastic outer gear, and the flexspline outer gear is tightly joined to the outer peripheral surface of the open end of the cylindrical main body by injection molding.

9. The flexible spline of a harmonic speed reducer according to claim 1, characterized in that: The cylindrical main body is connected to the wave generator assembly via an inner peripheral surface on the open end side thereof.

10. A harmonic reducer comprising a wave generator assembly and a rigid wheel; the rigid wheel having a rigid inner gear ring; the wave generator assembly comprising a wave generator; characterized in that: The wave generator assembly also includes a flexible bearing; the harmonic reducer also includes the flexible wheel described in any one of claims 1 to 9; the flexible bearing is installed between the wave generator and the open end of the cylindrical main body; the flexible wheel outer ring undergoes radial flexible deformation due to the rotation of the wave generator, thereby forming partial engagement with the rigid inner ring gear.

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