Cycloidal speed reducer

Abstract

The invention is suitable for the field of cycloidal speed reducers, and provides a cycloidal speed reducer which comprises a shell, an input mechanism, an output mechanism, a speed reduction mechanism and a limiting assembly, and is characterized in that the shell comprises a speed reduction supporting front shell and a speed reduction supporting rear shell, and threaded holes are formed in the speed reduction supporting front shell and the speed reduction supporting rear shell; threaded holes are formed in the speed reduction supporting front shell and the speed reduction supporting rear shell in an annular mode, the speed reduction supporting front shell and the speed reduction supporting rear shell are installed in a matched mode through screws, the machining cost of the cycloid speed reducer is reduced, the service life is prolonged, the loss of parts is smaller, meanwhile, the service life can be prolonged by replacing a quick-wear shaft sleeve, and the service life of the cycloid speed reducer is prolonged. And the use cost of the cycloidal-pin wheel speed reducer is further reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of the meshing structure of cycloid speed reducers, and particularly relates to a cycloid speed reducer. Background Art

[0002] With the maturity of the industrial robot industry and the rise of the humanoid robot industry, speed reducers using the cycloid meshing reduction principle (cycloid pinwheel speed reducers, RV speed reducers, etc.) have been widely used in the market. Due to its characteristics of higher stiffness, higher efficiency, and higher load capacity compared to its competitor - harmonic speed reducers, industrial robot manufacturers generally choose it as the first four joint speed reducers for medium-load robotic arms or all six joint speed reducers for heavy-load robotic arms. And due to the need of the mechanical control algorithm for the backdrivable ability (specifically reflected as low starting torque and high efficiency) in the emerging humanoid robot industry, there is also a trend to replace the non-backdrivable harmonic speed reducers with cycloid pinwheel speed reducers for the speed reducers of large joints (such as hip, knee, shoulder joints).

[0003] Since the outer rolling needles of the cycloid pinwheel speed reducer need to be constantly meshed with the cycloid wheel and perform rolling friction with the cycloid wheel and sliding friction with the support end at different meshing angles, the following two methods are generally used in the industry to mechanically constrain the outer ring of the rolling needles. Precision RV speed reducer manufacturers (such as Nabtesco) generally adopt the semi-circular housing direct constraint method, and process a semi-circular rolling needle groove on the steel housing to accommodate the rolling needles to roll in the groove. Such a constraint method has the characteristic of small volume, but since the rolling needles directly slide against the housing, the requirements for the wear resistance of the housing material and the machining accuracy are relatively high.

[0004] Cycloid pinwheel speed reducer manufacturers generally use the pin - bushing constraint method, and the bushing slides against the pins fixed on the housing. This constraint method occupies a relatively large volume, but since the housing does not participate in the sliding friction, the requirement for the wear resistance of the housing material is reduced, and only the machining accuracy of the pin - housing contact surface is required. Such a constraint method reduces the cost, and the material selection of the housing is more flexible.

[0005] The existing bushing bearing structure uses a rolling needle - bushing combination with a large length - diameter ratio due to the length of the cycloid wheel, which will cause unnecessary energy loss, reduce the operating efficiency of the cycloid pinwheel speed reducer, and increase the starting torque. Therefore, an outer rolling needle constraint method that can simultaneously meet the load - bearing capacity requirements and has the characteristics of low energy loss and low starting torque is very important for the industry using cycloid pinwheel speed reducers. Summary of the Invention

[0006] The present invention provides a cycloid speed reducer, aiming to solve the problem that the existing cycloid wheel speed reducer cannot simultaneously meet the load - bearing capacity requirements and has low energy loss.

[0007] The present invention is implemented as follows. A cycloid speed reducer includes a housing, an input mechanism, an output mechanism, a speed reduction mechanism, and a limiting component, and is characterized in that: the housing includes a front speed reduction support shell and a rear speed reduction support shell, and threaded holes are provided on both the front speed reduction support shell and the rear speed reduction support shell. The threaded holes are arranged in a circular manner on the front speed reduction support shell and the rear speed reduction support shell, and the front speed reduction support shell and the rear speed reduction support shell are installed in cooperation with screws; The input mechanism includes an input shaft and an active eccentric wheel assembly. The input shaft is installed in cooperation with an input hole at the center of the front speed reduction support shell through a bearing, and the active eccentric wheel assembly is installed on the input shaft; The speed reduction mechanism is installed in clearance fit with the active eccentric wheel assembly, and the speed reduction mechanism is located inside the housing; The output mechanism is installed in cooperation with the active eccentric wheel assembly. The output mechanism is located on the left side of the input shaft and away from the front speed reduction support shell. The speed reduction mechanism includes a passive eccentric wheel assembly and an output rotating shaft.

[0008] Furthermore, an axial restraint is installed inside the speed reduction mechanism.

[0009] Furthermore, the limiting component includes a positioning shaft and a positioning bearing sleeve. Positioning bearing holes are provided inside both the front speed reduction support shell and the rear speed reduction support shell. The positioning bearing holes are arranged in a circular manner inside the front speed reduction support shell and the rear speed reduction support shell. The positioning bearing sleeve is press-fitted in the positioning bearing hole, and the positioning shaft is installed between the two positioning bearing sleeves.

[0010] Furthermore, the passive eccentric wheel assembly is provided with a first transmission hole. The first transmission hole is arranged in a circular manner on the passive eccentric wheel assembly. The output rotating shaft penetrates through the first transmission hole, and the outer contour of the passive eccentric wheel assembly is installed in cooperation with the positioning bearing sleeve.

[0011] Furthermore, the output mechanism includes a first output roller disc and a second fixed disc. The first output roller disc is fixedly installed at the left end of the output rotating shaft, and the second fixed disc is fixedly installed at one end of the output rotating shaft away from the first output roller disc. The second fixed disc is installed in cooperation with the front speed reduction support shell through a bearing, and the first output roller disc is installed in cooperation with the rear speed reduction support shell through a bearing.

[0012] Furthermore, the first output roller disc is installed on the input shaft through a bearing. An axial step is provided on the input shaft, and the active eccentric wheel assembly is installed in cooperation with the input shaft through a bearing.

[0013] Furthermore, the positioning bearing sleeve has a copper content of more than 50%.

[0014] Furthermore, the length of the positioning bearing sleeve is denoted as L, the diameter is denoted as D, and the length-diameter ratio of the bushing bearing is denoted as LD. The value of LD is equal to L divided by D.

[0015] Beneficial effects achieved by the present invention: Since the front deceleration support housing and the rear deceleration support housing using the limiting component do not participate in sliding friction, the selection of the housing material is more diverse, and only the hole position accuracy of the positioning bearing holes on the housing needs to be ensured. At the same time, due to the large contact area and low contact stress between the positioning bearing sleeve and the positioning shaft, the material selection of the positioning bearing sleeve is more diverse than the existing constraint methods, such as low-cost powder metallurgy self-lubricating copper bushings. The processing cost of the cycloid reducer is reduced, the service life is extended, the loss of parts is smaller, and the service life can be extended by replacing the vulnerable bushings, further reducing the use cost of the cycloid pinwheel reducer. Description of the Drawings

[0016] Figure 1 is the overall first perspective structural schematic diagram of the present invention; Figure 2 is the overall second perspective structural schematic diagram of the present invention; Figure 3 is the overall third perspective structural schematic diagram of the present invention; Figure 4 is the first perspective structural schematic diagram of the deceleration structure of the present invention; Figure 5 is the second perspective structural schematic diagram of the deceleration structure of the present invention; Figure 6 is the cross-sectional view of the overall structure of the present invention.

[0017] Figure 7 is the structural schematic diagram of the deceleration structure in Embodiment 3 of the present invention.

[0018] In the figure: 1. Housing; 2. Input mechanism; 3. Output mechanism; 4. Deceleration mechanism; 5. Limiting component; 101. Front deceleration support housing; 102. Rear deceleration support housing; 201. Input shaft;; 203. Active eccentric wheel assembly; 301. First output roller; 302. Second fixed disk; 401. Passive eccentric wheel assembly; 405. First transmission hole; 408. Output rotating shaft; 501. Positioning shaft; 502. Positioning bearing sleeve; 503. Positioning bearing hole. Detailed Embodiments

[0019] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] Embodiment 1 Referring Figures 1 to 6 , the present invention is a cycloid reducer, including a housing 1, an input mechanism 2, an output mechanism 3, a reduction mechanism 4, and a limit component 5, characterized in that: the housing 1 includes a reduction support front housing 101, a reduction support rear housing 102, and a positioning shaft 103. Threaded holes are provided on both the reduction support front housing 101 and the reduction support rear housing 102, and the threaded holes are arranged in a circular pattern on the reduction support front housing 101 and the reduction support rear housing 102. The reduction support front housing 101 and the reduction support rear housing 102 are installed in cooperation with screws; The input mechanism 2 includes an input shaft 201 and a driving eccentric wheel assembly 203. The input shaft 201 is installed in cooperation with the input hole at the center of the reduction support front housing 101 through a bearing, and the driving eccentric wheel assembly 203 is installed on the input shaft 201; The reduction mechanism 4 is installed in clearance fit with the driving eccentric wheel assembly 203, and the reduction mechanism 4 is located inside the housing 1; The output mechanism 3 is installed in cooperation with the driving eccentric wheel assembly 203. The output mechanism 3 is located on the left side of the input shaft 201 and away from the reduction support front housing 101. The reduction mechanism 4 includes a driven eccentric wheel assembly 401 and an output rotating shaft 408.

[0021] An axial restraint is installed inside the reduction mechanism 4.

[0022] The limit component 5 includes a positioning shaft 501 and a positioning bearing sleeve 502. Positioning bearing holes 503 are provided inside both the reduction support front housing 101 and the reduction support rear housing 102. The positioning bearing holes 503 are arranged in a circular pattern inside the reduction support front housing 101 and the reduction support rear housing 102. The positioning bearing sleeve 502 is installed in the positioning bearing hole 503 in a rolling manner, and the positioning shaft 501 is installed between the two positioning bearing holes 503.

[0023] The driven eccentric wheel assembly 401 is provided with a first transmission hole 405. The first transmission hole 405 is arranged in a circular pattern on the driven eccentric wheel assembly 401. The output rotating shaft 408 passes through the first transmission hole 405, and the outer contour of the driven eccentric wheel assembly 401 is installed in cooperation with the positioning bearing sleeve 502.

[0024] The output mechanism 3 includes a first output roller 301 and a second fixed disk 302. The first output roller 301 is fixedly installed at the left end of the output rotating shaft 408, and the second fixed disk 302 is fixedly installed at the end of the output rotating shaft 408 away from the first output roller 301. The second fixed disk 302 is installed in cooperation with the reduction support front housing 101 through a bearing, and the first output roller 301 is installed in cooperation with the reduction support rear housing 102 through a bearing.

[0025] The first output roller 301 is mounted on the input shaft 201 through bearings. A shaft step is provided on the input shaft 201, and the driving eccentric wheel assembly 203 is mounted on the input shaft 201 in cooperation with bearings.

[0026] The working principle of the present invention is as follows: The input shaft 201 starts to rotate to provide torque, and the torque is transmitted to the driving eccentric wheel assembly 203. The driving eccentric wheel assembly 203 drives the driven eccentric wheel assembly 401 to rotate. The outer cycloid tooth surface of the driven eccentric wheel assembly 401 cooperates with the positioning shaft 501 to roll. The positioning shaft 501 realizes radial constraint on the driven eccentric wheel assembly 401. Due to the eccentric installation of the two driven eccentric wheel assemblies 401 arranged with a 180° phase difference, the minor diameter of the overlapping holes formed between the first transmission holes 405 is the diameter of the output rotating shaft 408. Therefore, when the driven eccentric wheel assembly 401 rotates, the output rotating shaft 408 and the output rotating shaft 408 perform a circular motion with the center of the input shaft as the origin. The output rotating shaft 408 transmits the torque to the first output roller 301 to achieve the effect of reducing speed and increasing torque.

[0027] The positioning bearing sleeve 502 has a copper content of more than 50%.

[0028] The length of the positioning bearing sleeve 502 is represented as L, the diameter is represented as D, and the length-diameter ratio of the bushing bearing is represented as LD. The value of LD is equal to L divided by D.

[0029] In this structure, the positioning shaft 501 is supported by the two-sided positioning bearing sleeves 502, which is similar to the simply supported beam structure in architecture. The two-sided positioning bearing sleeves 502 are respectively crimped on the front deceleration support housing 101 and the rear deceleration support housing 102. The front deceleration support housing 101 and the rear deceleration support housing 102 are rigidly connected together by screws and pins. The part of the positioning shaft 501 that does not insert into the positioning bearing sleeve 502 meshes with the driven eccentric wheel assembly 401.

[0030] This structure can reasonably match the suitable length-diameter ratio LD of the positioning bearing sleeve 502 according to the maximum load condition, so as to ensure the maximization of the efficiency of the positioning shaft 501 under the condition of meeting the load requirements. The length-diameter ratio LD of the two-sided positioning bearing sleeves 502 is 1, and the total loss under the same load is less than that of a positioning bearing sleeve 502 with a length-diameter ratio LD of 2. At the same time, its simply supported beam structure ensures the high rigidity of the positioning shaft 501 under load, meeting the requirements of industrial robots for high-rigidity speed reducers.

[0031] Since the front deceleration support housing 101 and the rear deceleration support housing 102 using the limit component do not participate in sliding friction, the selection of the material for the housing 1 is more diverse, and only the hole position accuracy of the positioning bearing hole 503 on the housing needs to be ensured. At the same time, due to the large contact area and low contact stress between the positioning bearing sleeve 502 and the positioning shaft 501, the material selection of the positioning bearing sleeve 502 is more diversified than the existing constraint methods, such as low-cost powder metallurgy self-lubricating copper bushings. The processing cost is reduced, the service life is extended, and the loss of components is smaller. At the same time, the service life can be extended by replacing the vulnerable bushings, further reducing the use cost of the cycloid pinwheel reducer.

[0032] Embodiment 2 Reference Figures 1 to 6 , based on Embodiment 1, this embodiment provides a three-piece passive eccentric wheel assembly 401, that is, the passive eccentric wheel assembly 401 includes a first passive eccentric wheel, a second passive eccentric wheel, and a third passive eccentric wheel, and the active eccentric wheel assembly 203 includes a first active eccentric wheel, a second active eccentric wheel, and a third active eccentric wheel. Bearings are installed on the outer sides of the first active eccentric wheel, the second active eccentric wheel, and the third active eccentric wheel.

[0033] The first passive eccentric wheel, the second passive eccentric wheel, and the third passive eccentric wheel are respectively installed in cooperation with the first active eccentric wheel, the second active eccentric wheel, and the third active eccentric wheel through bearings.

[0034] Embodiment 3 Reference Figures 1 to 7 , based on Embodiment 1, this embodiment provides a two-piece passive eccentric wheel assembly 401, that is, the passive eccentric wheel assembly 401 includes a first passive eccentric wheel and a second passive eccentric wheel, and the active eccentric wheel assembly 203 includes a first active eccentric wheel and a second active eccentric wheel. Bearings are installed on the outer sides of the first active eccentric wheel and the second active eccentric wheel.

[0035] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cycloid reducer, comprising a housing (1), an input mechanism (2), an output mechanism (3), a reduction mechanism (4) and a limit assembly (5), characterized in that: The housing (1) comprises a deceleration support front housing (101) and a deceleration support rear housing (102); threaded holes are provided on the deceleration support front housing (101) and the deceleration support rear housing (102); the threaded holes are arranged in a ring-shaped manner on the deceleration support front housing (101) and the deceleration support rear housing (102); the deceleration support front housing (101) and the deceleration support rear housing (102) are mounted by screws; The input mechanism (2) comprises an input shaft (201) and a driving eccentric wheel assembly (203); the input shaft (201) is mounted in cooperation with an input hole at the center of the speed reduction support front housing (101) via a bearing; the driving eccentric wheel assembly (203) is mounted on the input shaft (201); The speed reduction mechanism (4) is installed with clearance fit on the active eccentric wheel assembly (203), and the speed reduction mechanism (4) is located inside the housing (1); The output mechanism (3) is installed in cooperation with the active eccentric wheel assembly (203); the output mechanism (3) is located on the left side of the input shaft (201) and away from the reduction support front housing (101); and the reduction mechanism (4) comprises a passive eccentric wheel assembly (401) and an output rotating shaft (408).

2. A cycloid reducer according to claim 1, characterized in that: An axial restraining member is installed in the speed reduction mechanism (4).

3. A cycloid reducer according to claim 1, characterized in that: The limiting assembly (5) comprises a positioning shaft (501) and a positioning bearing sleeve (502); positioning bearing holes (503) are provided inside the deceleration support front shell (101) and the deceleration support rear shell (102); the positioning bearing holes (503) are arranged in a ring-shaped manner inside the deceleration support front shell (101) and the deceleration support rear shell (102); the positioning bearing sleeve (502) is crimped into the positioning bearing hole (503); and the positioning shaft (501) is installed between the two positioning bearing sleeves (502).

4. A cycloid reducer according to claim 3, characterized in that: The passive eccentric wheel assembly (401) is provided with a first transmission hole (405), the first transmission holes (405) are arranged in a ring shape on the passive eccentric wheel assembly (401), the output rotating shaft (408) passes through the first transmission hole (405), and the outer contour of the passive eccentric wheel assembly (401) is mounted in cooperation with the positioning bearing sleeve (502).

5. A cycloid reducer according to claim 1, characterized in that: The output mechanism (3) comprises a first output roller (301) and a second fixed plate (302), wherein the first output roller (301) is fixedly mounted on the left end of the output rotating shaft (408), and the second fixed plate (302) is fixedly mounted on an end of the output rotating shaft (408) away from the first output roller (301), the second fixed plate (302) and the deceleration support front shell (101) are mounted in cooperation with each other via a bearing, and the first output roller (301) and the deceleration support rear shell (102) are mounted in cooperation with each other via a bearing.

6. A cycloid reducer according to claim 5, characterized in that: The first output roller (301) is mounted on the input shaft (201) via a bearing, a shaft step is provided on the input shaft (201), and the active eccentric wheel assembly (203) is mounted on the input shaft (201) via a bearing.

7. A cycloid reducer according to claim 4, characterized in that: The positioning bearing sleeve (502) contains more than 50% copper.

8. A cycloid reducer according to claim 7, characterized in that: The length of the positioning bearing sleeve (502) is represented by L, the diameter is represented by D, and the length-to-diameter ratio of the sleeve bearing is represented by LD, and the value of LD is equal to L divided by D.

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