Harmonic reducer

Abstract

The present invention provides a harmonic reducer. The harmonic reducer comprises a rigid wheel (1), a flexible wheel (2) and a wave generator (3). The flexible wheel (2) is sleeved on the outer periphery of the wave generator (3), and the flexible wheel (2) is meshed with the rigid wheel (1). The wave generator (3) comprises an input shaft (4), a slider (5) and a flexible bearing (9). A plurality of sliders (5) are arranged along the circumference of the outer periphery of the input shaft (4). The outer contour of the plurality of sliders (5) after being combined in an unloaded state is a cam contour. The flexible wheel (2) is sleeved on the outer periphery of the flexible bearing (9). Within the angle θ range on both sides of the long axis of the wave generator (3), the inner peripheral wall of at least one slider (5) comprises a concave arc segment (6). The outer peripheral wall of the input shaft (4) corresponding to the slider (5) has an arc-shaped protrusion (7) adapted to the concave arc segment (6). According to the harmonic reducer of the present invention, it can realize self-protection when subjected to abnormal impact load to prevent the flexible wheel from being overloaded and torn.

Description

Technical Field

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

[0002] Harmonic reducers offer numerous advantages, including high transmission accuracy, high speed ratios, compact size, simple structure, and wide application. They consist of three basic components: a rigid wheel, a flexwheel, and a wave generator. In general, the rigid wheel is stationary, while the wave generator rotates, forcing the flexwheel to elastically deform, causing the teeth of the flexwheel to mesh with those of the rigid wheel, thereby achieving transmission.

[0003] The wave generator of a harmonic reducer is an elliptical structure, with its major axis slightly larger than the inner diameter of the flexspline. Therefore, after the wave generator is installed in the flexspline, the flexspline deforms to the contour of the wave generator at the open end. The flexspline is stretched outward near the major axis of the wave generator at the open end. Because the flexspline's circumference remains essentially unchanged, the flexspline contracts inward near the minor axis of the wave generator at the open end. Under normal operating conditions, the number of teeth in a dual-wave harmonic reducer that are simultaneously engaged can reach approximately 30-40% of the total number of teeth.

[0004] Harmonic reducers are commonly used in precision equipment such as industrial robots and high-precision turntables, which require high precision. These devices often experience impact overloads (including collisions caused by improper human operation) during operation. When a harmonic reducer is impacted, the forces on the flexspline teeth increase dramatically, causing the flexspline tooth roots to tear along the tooth width, leading to reducer failure. Furthermore, after the flexspline fails, the mechanical equipment loses the restraint of the reducer and swings freely, potentially injuring operators and other equipment.

[0005] Existing technologies usually take preventive measures in drive control and shut down the equipment in time for protection when it is impacted. However, this protection mechanism has a certain delay and cannot fundamentally guarantee the situation where the harmonic reducer fails to be installed.

[0006] An improved structure of the flexible wheel of a harmonic reducer is disclosed in the related technology. The flexible wheel is improved into a rigid fan-shaped external tooth structure distributed in an annular array of 8 teeth, and a reset spring is used to realize reciprocating motion, thereby realizing engagement and disengagement with the rigid internal teeth. However, the rigid external teeth are affected by the distribution position and number, and the operation and force are uneven, and cannot resist the impact of impact loads. Summary of the Invention

[0007] The main purpose of the present invention is to provide a harmonic reducer that can achieve self-protection when subjected to abnormal impact loads and prevent the flexible wheel from being overloaded and torn.

[0008] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a harmonic reducer is provided, comprising a rigid wheel, a flexwheel and a wave generator, wherein the flexwheel is sleeved on the outer periphery of the wave generator and meshes with the rigid wheel, the wave generator comprises an input shaft, a slider and a flexible bearing, wherein there are multiple sliders, and the multiple sliders are arranged along the circumference of the outer periphery of the input shaft, and the outer contour of the multiple sliders after being combined in the no-load state is a cam contour, the flexwheel is sleeved on the outer periphery of the flexible bearing, and within the angle θ range on both sides of the long axis of the wave generator, the inner circumferential wall of at least one slider comprises a concave arc segment, and the outer circumferential wall of the input shaft corresponding to the slider has an arc-shaped protrusion adapted to the concave arc segment.

[0009] Furthermore, within the angle θ range on both sides of the long axis of the wave generator, the inner peripheral wall of the slider includes a concave arc segment.

[0010] Furthermore, θ=30°~45°.

[0011] Furthermore, the inner peripheral wall of each slider includes a concave arc segment.

[0012] Furthermore, outside the region defined by the angle θ, the inner peripheral wall of at least one slider includes a convex arc segment, and the outer peripheral wall of the input shaft corresponding to the slider has an arc-shaped protrusion.

[0013] Furthermore, when the lowest point of the concave arc segment matches the highest point of the corresponding arc-shaped protrusion, the highest point of the convex arc segment matches the highest point of the corresponding arc-shaped protrusion.

[0014] Furthermore, the concave arc segment is a circular arc or cycloid structure.

[0015] Furthermore, the flexible bearing includes a plurality of balls arranged at intervals along the circumferential direction, and the circumferential width of each slider on the outer peripheral side is smaller than the minimum circumferential interval between two adjacent balls.

[0016] Furthermore, each slider has a fan-shaped structure.

[0017] Furthermore, during normal load operation, the positions of the slider and the input shaft are relatively static.

[0018] According to the technical solution of the present invention, the harmonic reducer includes a rigid wheel, a flexible wheel and a wave generator. The flexible wheel is sleeved on the outer periphery of the wave generator and meshes with the rigid wheel. The wave generator includes an input shaft and a slider. There are multiple sliders, and the multiple sliders are arranged along the circumference of the outer periphery of the input shaft. The outer contour of the multiple sliders after being combined in a no-load state is a cam contour. The flexible wheel is sleeved on the outer periphery of the slider. In the meshing area of ​​the flexible wheel and the rigid wheel, the inner circumferential wall of at least one slider includes a concave arc segment, and the outer circumferential wall of the input shaft corresponding to the slider has an arc-shaped protrusion adapted to the concave arc segment. The harmonic reducer has modified the structure of the wave generator, so that the wave generator includes an input shaft and a slider, and in the meshing area of ​​the flexible wheel and the rigid wheel, the inner circumferential wall of at least one slider includes a concave arc segment, and the outer circumferential wall of the input shaft corresponding to the slider has an arc-shaped protrusion adapted to the concave arc segment. When the harmonic reducer is subjected to an abnormal impact load, the input shaft and the slider move relative to each other in the circumferential direction, and circumferential displacement occurs between the slider and the input shaft. Since the concave arc segment of at least one slider in the meshing area is adapted to the arc-shaped protrusion of the input shaft, when the two undergo circumferential relative displacement, the arc-shaped protrusion will push the slider, causing the slider to produce radial displacement, thereby changing the outer contour of the wave generator. The outer contour of the changed wave generator is fuller in the meshing area of ​​the flexible wheel and the rigid wheel, and at the same time, the number of teeth involved in the meshing is increased, thereby reducing the load impact on a single tooth, achieving a self-protection effect, and preventing the flexible wheel from overload and tearing failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 A schematic structural diagram of a harmonic reducer according to an embodiment of the present invention is shown;

[0021] Figure 2 A schematic structural diagram of a wave generator of a harmonic speed reducer according to an embodiment of the present invention is shown;

[0022] Figure 3 A schematic diagram showing the structure of a wave generator of a harmonic reducer according to an embodiment of the present invention when it is subjected to a load impact;

[0023] Figure 4 A schematic diagram showing the movement of a slider when a wave generator of a harmonic speed reducer according to an embodiment of the present invention is subjected to a load impact is shown;

[0024] Figure 5 A schematic diagram of the enlarged structure of a wave generator at C of a harmonic reducer according to an embodiment of the present invention is shown;

[0025] Figure 6A schematic diagram showing an enlarged structure of a wave generator at D of a harmonic speed reducer according to an embodiment of the present invention; and

[0026] Figure 7 A schematic structural diagram of a wave generator of a harmonic reducer according to another embodiment of the present invention is shown.

[0027] The above drawings include the following reference numerals:

[0028] 1. Rigid pulley; 2. Flexspline; 3. Wave generator; 4. Input shaft; 5. Slider; 6. Concave arc segment; 7. Arc-shaped protrusion; 8. Convex arc segment; 9. Flexible bearing. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] See also Figures 1 to 7 As shown, according to an embodiment of the present invention, the harmonic reducer includes a rigid wheel 1, a flexible wheel 2 and a wave generator 3. The flexible wheel 2 is sleeved on the outer periphery of the wave generator 3 and meshes with the rigid wheel 1. The wave generator 3 includes an input shaft 4, a slider 5 and a flexible bearing 9. There are multiple sliders 5, and the multiple sliders 5 are arranged along the circumference of the outer periphery of the input shaft 4. The outer contour of the multiple sliders 5 after being combined in the no-load state is a cam profile. The flexible wheel 2 is sleeved on the outer periphery of the flexible bearing 9. Within the angle θ range on both sides of the long axis of the wave generator 3, the inner circumferential wall of at least one slider 5 includes a concave arc segment 6, and the outer circumferential wall of the input shaft 4 corresponding to the slider 5 has an arc-shaped protrusion 7 adapted to the concave arc segment 6.

[0031] The harmonic reducer has modified the structure of the wave generator 3, so that the wave generator 3 includes an input shaft 4 and a slider 5, and in the range of angle θ on both sides of the long axis of the wave generator 3, near the meshing area of ​​the flexible wheel 2 and the rigid wheel 1, the inner peripheral wall of at least one slider 5 includes a concave arc segment 6, and the outer peripheral wall of the input shaft 4 corresponding to the slider 5 has an arc-shaped protrusion 7 adapted to the concave arc segment 6. When the harmonic reducer is subjected to an abnormal impact load, the input shaft 4 and the slider 5 move relative to each other in the circumferential direction, and at this time, a circumferential rotation occurs between the slider 5 and the input shaft 4. Displacement. Since the concave arc segment 6 of at least one slider 5 near the meshing area is adapted to the arc-shaped protrusion 7 of the input shaft 4, when the two undergo circumferential relative displacement, the arc-shaped protrusion 7 will push the slider 5, causing the slider 5 to produce radial displacement, thereby changing the outer contour of the wave generator 3. The outer contour of the wave generator 3 after the change is fuller in the meshing area of ​​the flexspline 2 and the rigid wheel 1, and the number of teeth involved in the meshing is increased, thereby reducing the load impact on a single tooth, achieving a self-protection effect, and preventing the flexspline 2 from overload and tearing failure.

[0032] In one embodiment, it is necessary to add a pair of slider structures with concave arc segments 6 on both sides of at least the pair of meshing teeth at the outermost edge. When the harmonic reducer is subjected to load impact, the outer contour of the wave generator 3 can be adjusted by utilizing the relative displacement between the slider and the input shaft 4, so that the non-meshing teeth can participate in the meshing, thereby increasing the number of teeth participating in the meshing.

[0033] In this embodiment, the meshing area of ​​the flexspline 2 and the rigid wheel 1 is S, wherein the angle range defined by θ should be outside the meshing area S, thereby ensuring that when subjected to an impact load, the slider 5 outside the meshing area will undergo circumferential displacement relative to the input shaft 4, causing the original concave-convex matching structure to be dislocated. While the slider 5 slides relative to the input shaft 4, it will radially bulge outward under the thrust of the arc-shaped protrusion 7 of the input shaft 4, causing the outer contour close to the meshing area to be squeezed outward as a whole, thereby causing the gear teeth in the corresponding area of ​​the flexspline 2 to bulge outward, increasing the number of teeth meshing with the flexspline 2 and the rigid wheel 1, and further increasing the number of teeth bearing the load impact, so that the impact load that a single tooth needs to share is reduced, thereby achieving the purpose of reducing the impact load in the local area of ​​the flexspline to prevent the flexspline from overload and tearing failure.

[0034] In one embodiment, θ=30°-45°.

[0035] In this embodiment, the structure of a cam, corresponding to that of related art, is divided into two parts: circumferentially distributed sliders 5 and input shaft 4. When unloaded, adjacent sliders 5 contact each other, forming a conventional cam profile. The inner ring of the sliders 5, located 30° to 45° on either side of the major axis, is designed as a smooth transitional arc or cycloid structure with a concave center and convex edges. The outer contour of the input shaft 4 corresponds to that of the sliders 5, with a smooth transitional convex arc or convex cycloid structure between the concave center and the convex edges.

[0036] In this embodiment, the major axis is the position of the longest diameter. Since the cam is a symmetrical structure, the inner circumferential wall of the slider 5 is a concave arc segment with a major semi-axis angle range of 2θ, and the total concave arc segment angle range of the two major semi-axes is 4θ. θ is defined as the angle range of θ starting from the longest position of the major semi-axis as 0° and rotating left and right to the minor axis area, that is, θ represents the angle range starting from 0°, the minimum angle range is 0°-30°, and the maximum angle range is 0°-45°. Different models of reducers have different corresponding angle ranges.

[0037] See also Figure 7As shown, in one embodiment, the inner circumferential wall of each slider 5 includes a concave arc segment 6. In this embodiment, since the inner circumferential wall of each slider 5 is configured to include a concave arc segment 6, that is, each slider 5 forms a concave-convex fit with the arc-shaped protrusion 7 of the outer contour of the input shaft 4 through the concave arc segment 6, the sliders 5 on both sides of the major axis also meet the above-mentioned design requirements. When the harmonic reducer is subjected to load impact, the outer contour of the wave generator 3 can be made fuller in the meshing area of ​​the flexspline 2 and the rigid wheel 1. At the same time, the number of teeth involved in the meshing is increased, thereby reducing the load impact on a single tooth, achieving a self-protection effect, and preventing the flexspline 2 from overload and tearing failure.

[0038] When the slider 5 and the input shaft 4 rotate at an angle α, the slider 5 in the long axis area is pushed outward, while the position of the slider 5 near the short axis remains unchanged. At this time, when the impact load is eliminated, the outer contour of the wave generator 3 can be more easily restored to its original state.

[0039] See also Figure 2 As shown, in one embodiment, outside the region defined by the angle θ, the inner circumferential wall of at least one slider 5 includes a convex arc segment 8 , and the input shaft 4 has an arc-shaped protrusion 7 on the outer circumferential wall corresponding to the slider 5 .

[0040] In this embodiment, the convex arc segment 8 is provided on the slider 5 in the area near the minor axis, and can cooperate with the slider 5 with the concave arc segment 6 provided in the area near the major axis to protect the wave generator 3.

[0041] In one embodiment, the concave arc segment 6 is a circular arc or cycloid structure, which has a smoother transition structure, enabling the slider 5 to slide more smoothly relative to the input shaft 4 and more effectively reducing load impact.

[0042] In one embodiment, when the lowest point of the concave arc segment 8 matches the highest point of the corresponding arc-shaped protrusion 7 , the highest point of the convex arc segment 8 matches the highest point of the corresponding arc-shaped protrusion 7 .

[0043] When the harmonic reducer is subjected to an impact load, when the slider 5 near the long axis slides relative to the arc-shaped protrusion 7 of the input shaft 4, the slider 5 near the long axis expands outward under the push of the arc-shaped protrusion 7, and the inner ring of the flexible bearing 9 near the long axis is stretched. At this time, the slider 5 near the short axis also slides relative to the arc-shaped protrusion 7 of the input shaft 4. Since the slider 5 near the short axis is matched with the arc-shaped protrusion 7 through the convex arc segment 8, when the two slide relative to each other, the slider 5 near the short axis will shrink inward to compensate for the deformation amount required for the flexible bearing 9 to deform due to the outward expansion of the slider 5 near the long axis, thereby keeping the interference between the cam structure formed by the slider 5 and the input shaft 4 and the flexible bearing 9 unchanged, thereby effectively protecting the flexible bearing 9 and further achieving effective protection for the wave generator 3.

[0044] In one embodiment, the flexible bearing 9 includes a plurality of balls spaced circumferentially, and the circumferential width of each slider 5 on the outer peripheral side is smaller than the minimum circumferential interval between two adjacent balls, thereby achieving higher adjustment accuracy.

[0045] In one embodiment, each slider 5 is a fan-shaped structure, and multiple fan-shaped structures cooperate with each other to form a complete cam after combination, which meets the driving requirements of the flexible bearing 9 and can ensure the coordination effect between adjacent sliders 5.

[0046] In one embodiment, during normal load operation, the positions of the slider 5 and the input shaft 4 are relatively static.

[0047] Figure 7 The numerical values ​​on the sliders 5 represent the numbers of the sliders, which are for the convenience of distinguishing different sliders and do not represent reference numerals.

[0048] See also Figures 4 to 6 As shown, during operation of the harmonic reducer, when subjected to an abnormal impact load, the input shaft 4 and slider 5 produce a relative rotation angle α. At this time, the convex arc or convex cycloid structure near the major axis of the input shaft 4 pushes slider a, causing it to produce radial displacement, thereby changing the outer contour of the wave generator 3. The modified outer contour of the wave generator 3 becomes fuller near the major axis, increasing the area where the rigid wheel teeth and the flexible wheel teeth participate in meshing, that is, increasing the number of teeth participating in simultaneous meshing, thereby reducing the load impact on a single tooth, achieving a self-protection effect, and preventing the flexible wheel from overload tearing and failure. At the same time, the slider b near the minor axis contracts, thereby ensuring that the flexible bearing 9 is not stretched.

[0049] After the impact load is removed, the relative rotation angle α between the input shaft 4 and the slider 5 resets because the flexible bearing 9 tends to maintain its initial circular shape, and the outer contour of the wave generator 3 returns to its normal operating state. Since the flexspline 2 of the harmonic reducer continuously reciprocates during operation, the harmonic reducer with the outer contour of the wave generator 3 reset can avoid premature failure caused by excessive deformation of the flexspline due to changes in the outer contour of the wave generator 3.

[0050] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0051] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A harmonic reducer, characterized in that: The invention comprises a rigid wheel (1), a flexible wheel (2) and a wave generator (3), wherein the flexible wheel (2) is sleeved on the outer periphery of the wave generator (3), the flexible wheel (2) is meshed with the rigid wheel (1), the wave generator (3) comprises an input shaft (4), a slider (5) and a flexible bearing (9), the sliders (5) are multiple, the multiple sliders (5) are arranged along the circumference of the outer periphery of the input shaft (4), the outer contour of the multiple sliders (5) after being combined in an unloaded state is a cam contour, the flexible wheel (2) is sleeved on the outer periphery of the flexible bearing (9), within the angle θ range of each side on both sides of the long axis of the wave generator (3), the inner peripheral wall of at least one slider (5) includes a concave arc segment (6), and the outer peripheral wall of the input shaft (4) corresponding to the slider (5) has an arc-shaped protrusion (7) adapted to the concave arc segment (6).

2. The harmonic reducer according to claim 1, characterized in that: Within the range of an angle θ on both sides of the long axis of the wave generator (3), the inner peripheral wall of the slider (5) includes a concave arc segment (6).

3. The harmonic reducer according to claim 2, characterized in that: θ=30°~45°.

4. The harmonic reducer according to claim 1, characterized in that: The inner peripheral wall of each slider (5) includes a concave arc segment (6).

5. The harmonic reducer according to any one of claims 1 to 3, characterized in that: Outside the area defined by the angle θ, the inner peripheral wall of at least one of the sliders (5) includes a convex arc segment (8), and the outer peripheral wall of the input shaft (4) corresponding to the slider (5) has the arc-shaped protrusion (7).

6. The harmonic reducer according to claim 5, characterized in that: When the lowest point of the concave arc segment (6) matches the highest point of the corresponding arc-shaped protrusion (7), the highest point of the convex arc segment (8) matches the highest point of the corresponding arc-shaped protrusion (7).

7. The harmonic reducer according to any one of claims 1 to 4, characterized in that: The concave arc segment (6) is a circular arc or cycloid structure.

8. The harmonic reducer according to any one of claims 1 to 4, characterized in that: The flexible bearing (9) comprises a plurality of balls arranged at intervals along the circumferential direction, and the circumferential width of each slider (5) on the outer peripheral side is smaller than the minimum circumferential interval between two adjacent balls.

9. The harmonic reducer according to any one of claims 1 to 4, characterized in that: Each of the sliders (5) is a fan-shaped structure.

10. The harmonic reducer according to any one of claims 1 to 4, characterized in that: During normal load operation, the positions of the slider (5) and the input shaft (4) are relatively stationary.

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