A harmonic reducer

Abstract

The present invention provides a harmonic reducer, which includes: a wave generator, the wave generator includes a flexible bearing and two or more cams, the two or more cams are arranged on the radial inner side of the flexible bearing, and the two or more cams are arranged along the circumferential direction of the inner circumference of the flexible bearing, and the radial inner side of the two or more cams is also provided with a motor shaft or an assembly tool, when the two or more cams are assembled into the flexible bearing, the cam does not produce extrusion deformation on the inner circumference of the flexible bearing, and when the motor shaft or the assembly tool is assembled into the two or more cams, the inner circumference of the flexible bearing is extruded and deformed through the cam. The present invention can prevent the cam from interfering with the flexible wheel or the flexible bearing during assembly, and can effectively reduce the assembly cost; it can improve the transmission accuracy, and achieve a higher transmission ratio transmission under different rigid wheel forms.

Description

Technical Field

[0001] The invention belongs to the technical field of reducers, and in particular relates to a harmonic reducer. Background Art

[0002] Reducers have the characteristics of high precision, high torque, low vibration and rapid response, so they are widely used in different fields such as industrial robots, mechanical equipment, aerospace, communication equipment, optical equipment, etc. Among them, harmonic reducers, RV reducers and planetary gear reducers are mainly used in the field of industrial robots. Harmonic reducers have obvious advantages when applied to some joints of robots due to their high transmission accuracy, high efficiency, stable transmission and small size.

[0003] The harmonic reducer achieves the deceleration function through the meshing tooth difference between the flex spline and the rigid wheel, and the meshing effect between the flex spline and the rigid wheel is mainly achieved through the action of the wave generator on the flex spline. The different contour shapes of the wave generator will cause the number of meshing teeth between the flex spline and the rigid wheel to differ.

[0004] At present, wave generators mainly include elliptical cam and cosine cam wave generators. It can be seen from patent CN107893840A that wave generators with multiple wave numbers can also achieve different meshing teeth numbers of the flexible wheel and the rigid wheel, thereby affecting the deceleration effect of the reducer. However, since the design of the harmonic reducer is that the wave generator opens the flexible wheel, and the flexible wheel is deformed and then meshes with the rigid wheel, the size of the wave generator itself is larger than that of the flexible wheel, and direct assembly will cause interference.

[0005] In the existing patent CN207583964U, a wave generator that automatically adjusts the meshing clearance can solve the interference problem in assembly by adjusting the automatic opening and closing of the cam, but the given cam structure is complex and costly, and it is difficult to adjust the clearance between the rigid wheel teeth and the flexible wheel teeth of the harmonic gear reducer by adjusting the bolts, and the accuracy is difficult to ensure. Moreover, this method can only achieve the meshing of the flexible wheel and the rigid wheel in this special double-wave form, and does not have good scalability.

[0006] Since the wave generator and the flexible wheel in the harmonic reducer in the prior art are prone to interference during assembly, the size of the wave generator in the long axis direction is difficult to control, it is difficult to achieve multi-wave number meshing of the flexible wheel and the rigid wheel, and the overall transmission accuracy is low, etc., the present invention studies and designs a harmonic reducer. Summary of the invention

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the wave generator and the flexible wheel in the harmonic reducer in the prior art are prone to interference when assembled, thereby providing a harmonic reducer.

[0008] The present invention provides a harmonic reducer, comprising:

[0009] A wave generator, the wave generator includes a flexible bearing and two or more cams, the two or more cams are arranged on the radial inner side of the flexible bearing, and the two or more cams are arranged in the circumferential direction of the inner periphery of the flexible bearing, and a motor shaft or an assembly tool is also arranged on the radial inner side of the two or more cams. When the two or more cams are assembled into the flexible bearing, the cams do not produce extrusion deformation on the inner peripheral surface of the flexible bearing, and when the motor shaft or the assembly tool is assembled into the two or more cams, the inner peripheral surface of the flexible bearing is extruded and deformed through the cams.

[0010] Preferably,

[0011] The motor shaft or the assembly tool is respectively in contact with the two or more cams to drive the two or more cams to rotate simultaneously. The motor shafts or assembly tooling of different sizes can generate different deformation amounts on the flexible bearing through the cams.

[0012] Preferably,

[0013] It also includes a rigid wheel and a flexible wheel, the cam is sleeved on the outer periphery of the motor shaft or the assembly tooling, the flexible bearing is sleeved on the outer periphery of the cam, the flexible wheel is sleeved on the outer periphery of the flexible bearing, and the rigid wheel is sleeved on the outer periphery of the flexible wheel.

[0014] Preferably,

[0015] A receiving groove is provided at the central position of the radial inner side of the cam, and the receiving groove receives a portion of the motor shaft or the assembly tooling is provided therein.

[0016] Preferably,

[0017] The receiving groove is arranged at the central position of the radial inner side of each cam, and the plurality of receiving grooves form a slot for clamping the motor shaft or the assembly tool, and the plurality of cams are respectively clamped with the motor shaft or the assembly tool.

[0018] Preferably,

[0019] The clamping connection is formed between the inner circumference of the receiving groove of the cam and the outer circumference of the motor shaft or the assembly tool by means of a key connection or a pin connection.

[0020] Preferably,

[0021] The cross-sectional shape of the cam is a semicircular ring structure, and the receiving groove at the center of the radial inner side of the cam of the semicircular ring structure is a semicircular structure.

[0022] Preferably,

[0023] The number of the cams is two and they are arranged along the circumferential direction of the inner periphery of the flexible bearing.

[0024] Preferably,

[0025] The cross-sectional shape of the cam is a fan-shaped structure, and the receiving groove at the center of the radial inner side of the cam of the fan-shaped ring structure is a fan-shaped structure.

[0026] Preferably,

[0027] At least three cams are arranged along the circumferential direction of the inner circumference of the flexible bearing.

[0028] The harmonic reducer provided by the present invention has the following beneficial effects:

[0029] 1. The present invention can reduce the size of a single cam by making the wave generator include more than two cams, and the inner side of the cam is also provided with a motor shaft or an assembly tool. The assembly sequence is that the two or more cams are first installed in the flexible bearing, and then the motor shaft or the assembly tool is installed in the cam. When the motor shaft or the assembly tool is not installed in the cam, the two or more cams will not squeeze and deform the inner circumference of the flexible bearing. After the motor shaft or the assembly tool is installed in the cam, the cam can squeeze and deform the inner circumference of the flexible bearing, so that the cam will not interfere with the flexible wheel or the flexible bearing during assembly, and the assembly cost can be effectively reduced; wave generators composed of different numbers of cams can be selected, and the number of cams can form wave generators with different wave numbers, so that the flexible wheel and the rigid wheel can be meshed with multiple wave numbers, different reduction ratios can be achieved, and the transmission accuracy can be improved, and a higher transmission ratio can be achieved under different rigid wheel forms;

[0030] 2. The present invention also enables the motor shafts or assembly tools of different sizes to produce the above-mentioned different deformation amounts on the flexible bearing through the cam, so that the motor shaft of appropriate size can control the deformation degree of the wave generator, thereby controlling the deformation of the flexible wheel, and can achieve different degrees of engagement between the flexible wheel and the rigid wheel as needed, increase the number of meshing teeth, and improve the overall transmission accuracy; the motor shaft or appropriate tooling is used in conjunction with the cam to ensure the stability of the wave generator during assembly, and the deformed contour of the wave generator is more uniform and reasonable, which is conducive to the subsequent engagement of the flexible wheel and the rigid wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a top view of the internal cross-sectional view of the harmonic reducer of the present invention;

[0032] Figure 2 for Figure 1 Schematic diagram of the cross section in the AA direction (double corrugated reducer);

[0033] Figure 3 for Figure 2A cross-sectional schematic diagram of an alternative embodiment (three-wave reducer).

[0034] The reference numerals in the figure are as follows:

[0035] 1. Motor shaft or assembly tool; 2. Wave generator; 3. Flexwheel; 4. Rigid wheel; 5. Rigid bearing; 6. Cam; 61. Receiving groove; 7. Flexible bearing. DETAILED DESCRIPTION

[0036] like Figure 1-3 As shown, the present invention provides a harmonic reducer, which includes:

[0037] A wave generator 2 and a flexible wheel 3, wherein the wave generator 2 includes more than two cams 6 and a flexible bearing 7, wherein the more than two cams 6 are arranged on the radial inner side of the flexible bearing 7, and the more than two cams 6 are arranged in the circumferential direction of the inner periphery of the flexible bearing 7, and a motor shaft or an assembly tool 1 is also arranged on the radial inner side of the more than two cams 6, and when the more than two cams 6 are assembled into the flexible bearing 7, the cams 6 do not produce extrusion deformation on the inner peripheral surface of the flexible bearing 7, and when the motor shaft or the assembly tool 1 is assembled into the more than two cams 6, the inner peripheral surface of the flexible bearing 7 is extruded and deformed through the cams 6.

[0038] The present invention makes the wave generator include more than two cams, so that the size of a single cam can be reduced, and a motor shaft or an assembly tool is also arranged on the inner side of the cam. The assembly sequence is that the more than two cams are first installed in the flexible bearing, and then the motor shaft or the assembly tool is installed in the cam. When the motor shaft or the assembly tool is not installed in the cam, the more than two cams will not squeeze and deform the inner circumference of the flexible bearing. After the motor shaft or the assembly tool is installed in the cam, the cam can squeeze and deform the inner circumference of the flexible bearing, so that the cam will not interfere with the flexible wheel or the flexible bearing during assembly, and the assembly cost can be effectively reduced. Wave generators composed of different numbers of cams can be selected, and the number of cams can form wave generators with different wave numbers, so that multiple wave numbers of the flexible wheel and the rigid wheel can be meshed, different reduction ratios can be achieved, and the transmission accuracy can be improved, and a higher transmission ratio transmission can be achieved under different rigid wheel forms.

[0039] The present invention solves the interference problem when assembling the wave generator and the flexible wheel by cutting the wave generator and using motor shafts of different sizes to match the wave generator, and the assembly method is more convenient. Since the size of the motor shaft is controllable, the size of the flexible wheel opened by the wave generator can also be accurately controlled, and the meshing accuracy of the flexible wheel and the rigid wheel can also be improved. Since the wave generator is composed of different parts after cutting, the number of components of different parts can be selected to realize the meshing section of multiple wave numbers of the flexible wheel and the rigid wheel, realize different reduction ratios and improve transmission accuracy.

[0040] Preferably,

[0041] The motor shaft or assembly tool 1 is respectively in contact with the two or more cams 6 to drive the two or more cams 6 to rotate at the same time. The motor shafts or assembly tool 1 of different sizes can produce the above-mentioned different deformation amounts on the flexible bearing through the cam 6. The motor shafts or assembly tool 1 of different sizes can also produce the above-mentioned different deformation amounts on the flexible bearing through the cam, so that the motor shaft of appropriate size can control the deformation degree of the wave generator, thereby controlling the deformation of the flexible wheel, and can achieve different degrees of meshing of the flexible wheel and the rigid wheel as needed, increase the number of meshing teeth, and improve the overall transmission accuracy; the motor shaft or appropriate tool cooperates with the cam to ensure the stability of the wave generator during assembly, and the contour of the wave generator after deformation is more uniform and reasonable, which is conducive to the subsequent meshing of the flexible wheel and the rigid wheel.

[0042] The present invention: 1. Figure 1 The flexible wheel 3 is deformed under the action of the wave generator 2 (including the cam 6). The wave generator 2 is relatively large in size, and the flexible wheel 3 is stretched open when assembled with the flexible wheel 3. Figure 2 and Figure 3 A new type of assembly method is to put the small-sized cam 6 into the flexible bearing and use the motor shaft for assembly to solve the interference problem in assembly, which is convenient for assembly;

[0043] 2. The novel assembly method 1 provides a method for a wave generator 2 to support the flexible wheel. The size of the motor shaft can be controlled to control the deformation size of the motor shaft supporting the flexible bearing 7, thereby controlling the size of the flexible bearing 7 supporting the flexible wheel 3, affecting the fit between the flexible wheel 3 and the rigid wheel 4. The size of the motor shaft can be fine-tuned as needed, and can also be adjusted through other tooling parts;

[0044] 3. Through the methods mentioned in 1 and 2, the following can be achieved: Figure 3 The multi-waveform harmonic reducer shown in the figure can obtain harmonic reducers with different waveforms by changing the cam components and subdividing the cam profile and then cooperating with a flexible bearing. The more waveforms, the more teeth mesh, and the higher the transmission accuracy.

[0045] Preferably,

[0046] It also includes a rigid wheel 4 and a flexible wheel 3, the cam 6 is sleeved on the outer periphery of the motor shaft or the assembly tool 1, the flexible bearing 7 is sleeved on the outer periphery of the cam 6, the flexible wheel 3 is sleeved on the outer periphery of the flexible bearing 7, and the rigid wheel 4 is sleeved on the outer periphery of the flexible wheel 3. This is the preferred structural form of the present invention, that is, the rigid wheel, the flexible wheel and their related connection relationship can effectively drive the cam through the motor shaft or the assembly tool, drive the cam to rotate, the cam then drives the flexible bearing to rotate, the flexible bearing then drives the flexible wheel to rotate, and the outer teeth of the flexible wheel are meshed with each other through the inner teeth of the rigid wheel to drive the rigid wheel to rotate, thereby achieving the purpose of transmission, and achieving the effect of harmonic deceleration by reducing the transmission ratio.

[0047] Preferably,

[0048] The cam 6 is provided with a receiving groove 61 at the center of the radial inner side, and the receiving groove 61 receives part of the motor shaft or the assembly tool 1. By providing the receiving groove on the radial inner side of the cam, part of the motor shaft or the assembly tool can be received therein, and the motor shaft or the assembly tool can be assembled through the joint action of multiple receiving grooves to realize the function of rotation transmission and driving.

[0049] Preferably,

[0050] The central position of the radial inner side of each cam 6 is provided with the receiving groove 61, and the plurality of receiving grooves 61 form a slot for clamping the motor shaft or the assembly tool 1, and the plurality of cams 6 are respectively clamped with the motor shaft or the assembly tool 1. The plurality of receiving grooves clamp the motor shaft or the assembly tool therein and form a space clamping groove for rotational drive, and the cam and the motor shaft or the assembly tool also realize the function of circumferential limiting through clamping, so that the motor shaft or the assembly tool can drive the cam to rotate.

[0051] Preferably,

[0052] The inner circumference of the receiving groove 61 of the cam 6 and the outer circumference of the motor shaft or the assembly tool 1 are connected by a key connection or a pin connection to form the clamping connection. This is the preferred clamping form between the inner circumference of the cam receiving groove and the outer circumference of the motor shaft or the assembly tool of the present invention. The key connection or the pin connection can form a circumferential limit between the cam and the motor shaft or the assembly tool to complete the rotation drive function.

[0053] Preferably,

[0054] The cross-sectional shape of the cam 6 is a semicircular ring structure, and the receiving groove 61 at the center of the radial inner side of the cam 6 of the semicircular ring structure is a semicircular structure. This is the preferred structural form of the cam of the present invention. Figure 2As shown, it is a semicircular ring structure, which can be spliced ​​with a cam of another semicircular ring structure to form a roughly circular ring structure in the circumferential direction, basically filling the circular space inside the flexible bearing to achieve a two-wave structure.

[0055] Preferably,

[0056] The cams 6 are arranged in two circumferential directions along the inner periphery of the flexible bearing 7. This is a further preferred number and structure of the cams of the present invention, and the two cams can be spliced ​​into a roughly annular structure to basically fill the circular space inside the flexible bearing, thereby realizing a structure with two wave numbers.

[0057] Preferably,

[0058] The cross-sectional shape of the cam 6 is a fan-shaped structure, and the receiving groove at the center of the radial inner side of the cam 6 of the fan-shaped structure is a fan-shaped structure. This is a structural form of an alternative embodiment of the cam of the present invention, such as Figure 3 As shown, it is a fan-shaped ring structure, which can be spliced ​​with the cams of other two fan-shaped ring structures to form a roughly circular ring structure in the circumferential direction, basically filling the annular space inside the flexible bearing to achieve a three-wave structure.

[0059] Preferably,

[0060] The cams 6 are arranged in three directions along the inner periphery of the flexible bearing 7. This is a further preferred number and structure of the cams of the present invention, and the three cams can be spliced ​​into a roughly annular structure to basically fill the circular space inside the flexible bearing, thereby realizing a structure with three wave numbers.

[0061] Preferred embodiment:

[0062] like Figure 2 and Figure 3 :Multi-wave combination cam 6( Figure 2 For two wave numbers, Figure 3 The multi-wave combination cam 6 is placed in the flexible bearing 7 to achieve multi-wave meshing of the flexible wheel 3 and the rigid wheel 4, with a large number of meshing teeth, and a larger reduction ratio and transmission accuracy. When the multi-wave combination cam 6 is placed in the flexible bearing 7, it does not interfere with the bearing due to its small size, and the assembly is more convenient; the flexible bearing 7 and the flexible wheel 3 can be deformed to different degrees by changing the size of the motor shaft or the assembly tool 1, and the meshing depth of the flexible wheel 3 and the rigid wheel 4 can be easily adjusted according to the size of the rigid wheel 4, which can improve the transmission performance of the reducer.

[0063] like Figure 2 , Figure 3, assuming that the difference in the number of teeth between the flexible wheel 3 and the rigid wheel 4 is n, and the number of teeth of the rigid wheel is N, when the flexible wheel 3 inputs and the rigid wheel 4 outputs, the reduction ratio is N / |n|. Figure 2 becomes Figure 3 When the structure is adopted, the number of meshing teeth between the flexible wheel 3 and the rigid wheel 4 will increase, and the increase in the number of meshing teeth will improve the overall transmission performance.

[0064] Figure 1 The medium wave generator 2 is installed in the flexible wheel 3. In order to open the meshing of the flexible wheel 3 and the rigid wheel 4, the wave generator 2 is large in size and will interfere with the flexible wheel 3. Figure 2 , Figure 3 The cam 6 in the wave generator 2 is redesigned into a smaller-sized segmented cam. The cam 6 is directly placed in the flexible bearing 7 and then spread open by the motor shaft 1 or an assembly tool, making assembly more convenient.

[0065] The control of the expansion size of the flexible wheel 3 is adjusted by adjusting the size of the motor shaft or the assembly tool 1. The size of the motor shaft or the assembly tool 1 controls the deformation size of the flexible bearing 7 and the flexible wheel 3, thereby achieving different degrees of engagement between the flexible wheel 3 and the rigid wheel 4. The variable of the flexible wheel 3 can be controlled by adjusting the motor shaft or the assembly tool size 1 according to the size of the rigid wheel 4.

[0066] The above invention design can reduce the difficulty of assembling the wave generator and the flexible wheel, and can control the meshing depth and meshing teeth number of the flexible wheel and the rigid wheel, so as to achieve better transmission performance. The deformation degree of the flexible wheel adjusted by the motor shaft can be adjusted by other tooling, and the change of size can also be more accurately controlled by the tooling.

[0067] The present invention solves the following technical problems

[0068] 1. Combining cams with different wave numbers and flexible wheel bearings. Since the cams are small in size, there will be no interference problems when they are matched, which can reduce the assembly cost.

[0069] 2. Using a motor shaft or appropriate tooling to match the cam can make assembly more convenient.

[0070] 3. A motor shaft of appropriate size can control the deformation degree of the wave generator, thereby controlling the deformation of the flexible wheel, and can achieve different degrees of engagement between the flexible wheel and the rigid wheel as needed.

[0071] 4. Use the motor shaft or appropriate tooling to cooperate with the cam to ensure the stability of the wave generator during assembly. The deformed contour of the wave generator is more uniform and reasonable, which is conducive to the subsequent meshing of the flexible wheel and the rigid wheel.

[0072] 5. The number of cam components can form wave generators with different wave numbers, so that different degrees of engagement between the flexible wheel and the rigid wheel can be achieved, thus achieving different reduction ratios and improving transmission accuracy.

[0073] 1. Solved the problem of interference between the wave generator and the flexible wheel during assembly

[0074] 2. Solved the problem of wave generator size control in the long axis direction of the cam

[0075] 3. Solved the problem of multiple wave numbers of meshing between flexible wheel and rigid wheel

[0076] 4. Through the above, a convenient assembly method can be achieved, which can improve the overall transmission accuracy.

[0077] Beneficial effects:

[0078] This solution can make the assembly of the wave generator and the flexible wheel more convenient, that is, the interference problem caused by the wave generator being larger than the flexible wheel will not occur, thus reducing the assembly cost;

[0079] The deformation degree of the wave generator can be controlled by controlling the size of the motor shaft or the assembly tooling, thereby controlling the deformation of the flexspline and realizing the meshing control of the flexspline and the rigid wheel;

[0080] The wave generator composed of different numbers of cams can be selected to realize multi-wave meshing of the flexible wheel and the rigid wheel, which can improve the transmission accuracy and realize higher transmission ratio transmission under different rigid wheel forms.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A harmonic reducer, characterized in that: include: A wave generator (2), the wave generator (2) comprising a flexible bearing (7) and two or more cams (6), the two or more cams (6) being arranged on the radial inner side of the flexible bearing (7), and the two or more cams (6) being arranged in a circumferential direction along the inner circumference of the flexible bearing (7), and a motor shaft or an assembly tool (1) being arranged on the radial inner side of the two or more cams (6), the assembly sequence being that the two or more cams are first installed in the flexible bearing, and then the motor shaft or the assembly tool is installed in the cam, when the two or more cams (6) are installed in the flexible bearing (7), the cams (6) do not produce extrusion deformation on the inner circumference of the flexible bearing (7), but when the motor shaft or the assembly tool (1) is installed in the two or more cams (6), the inner circumference of the flexible bearing (7) is extruded and deformed through the cams (6); the number of cams formed forms a wave generator with different wave numbers.

2. The harmonic reducer according to claim 1, characterized in that: The motor shaft or assembly tool (1) is respectively in contact with the two or more cams (6) to simultaneously drive the two or more cams (6) to rotate. The motor shafts or assembly tool (1) of different sizes can generate different amounts of deformation on the flexible bearing through the cams (6).

3. The harmonic reducer according to claim 2, characterized in that: It also comprises a rigid wheel (4) and a flexible wheel (3), wherein the cam (6) is sleeved on the outer circumference of the motor shaft or the assembly tool (1), the flexible bearing (7) is sleeved on the outer circumference of the cam (6), the flexible wheel (3) is sleeved on the outer circumference of the flexible bearing (7), and the rigid wheel (4) is sleeved on the outer circumference of the flexible wheel (3).

4. The harmonic reducer according to claim 2 or 3, characterized in that: A receiving groove (61) is provided at a central position of the radial inner side of the cam (6), and the receiving groove (61) receives a portion of the motor shaft or the assembly tool (1) therein.

5. The harmonic reducer according to claim 4, characterized in that: The receiving groove (61) is provided at the central position of the radial inner side of each cam (6), and the plurality of receiving grooves (61) form a slot for clamping the motor shaft or the assembly tool (1), and the plurality of cams (6) are respectively clamped with the motor shaft or the assembly tool (1).

6. The harmonic reducer according to claim 5, characterized in that: The clamping connection is formed between the inner circumference of the receiving groove (61) of the cam (6) and the outer circumference of the motor shaft or the assembly tool (1) by means of a key connection or a pin connection.

7. The harmonic reducer according to any one of claims 4 to 6, characterized in that: The cross-sectional shape of the cam (6) is a semicircular ring structure, and the accommodating groove (61) at the center of the radial inner side of the cam (6) of the semicircular structure is a semicircular structure.

8. The harmonic reducer according to claim 7, characterized in that: The cams (6) are two arranged in a circumferential direction along the inner periphery of the flexible bearing (7).

9. The harmonic reducer according to any one of claims 4 to 6, characterized in that: The cross-sectional shape of the cam (6) is a fan-shaped structure, and the receiving groove at the center of the radial inner side of the cam (6) of the fan-shaped structure is a fan-shaped structure.

10. The harmonic reducer according to claim 9, characterized in that: The cams (6) are at least three arranged in a circumferential direction along the inner periphery of the flexible bearing (7).

Images