Cycloid reducer
The cycloidal speed reducer addresses weight and wear issues by using harder sliding protective members with specific penetration lengths, enabling a smaller, lighter design that maintains rigidity and power performance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- THK CO LTD
- Filing Date
- 2024-11-07
- Publication Date
- 2026-05-19
AI Technical Summary
Conventional cycloidal speed reducers used in mobile robots require lighter materials to improve power performance, but using lightweight metals like aluminum alloys leads to increased wear, weight, and reduced rigidity due to sliding protection members, which complicates miniaturization and weight reduction efforts.
A cycloidal speed reducer design with first and second sliding protective members made of harder materials than the output flange and carrier member, where the first member is thinner and the penetration length into the flange is longer than into the carrier member, ensuring rigidity and minimizing weight increase.
The design allows for a smaller, lighter cycloidal speed reducer that maintains rigidity and prevents wear, achieving weight reduction without increasing the output pin diameter or fitting length, thus enhancing power performance and miniaturization.
Smart Images
Figure 2026082400000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a cycloid speed reducer.
Background Art
[0002] Conventionally, a cycloid speed reducer is known as a speed reducer. The cycloid speed reducer is used in various applications, for example, in industrial robots and automotive parts. The cycloid speed reducer converts the rotation and torque obtained from a drive unit such as a motor or an internal combustion engine into a predetermined torque and rotational speed.
[0003] Such cycloid speed reducers are known in various forms. For example, as described in Patent Document 1, it includes a pair of curve plates, the curve plates are arranged with a phase shift of about 180° from each other, and the curve plates are sandwiched between an output flange and a carrier member axially connected by an output pin.
[0004] According to such a cycloid speed reducer, since the curve plates are arranged with a phase shift of 180° from each other, vibration can be reduced and the number of meshes can be increased. Since the output side has a cage shape by the output flange and the carrier member, the efficiency and robustness of power transmission can be improved.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0006] However, when cycloidal speed reducers are used in mobile robots and the like, lighter speed reducers are required to improve power performance. Conventional cycloidal speed reducers have used hardened iron-based materials for components such as output flanges and carrier members, but in order to reduce weight, lighter metals such as aluminum alloys are sometimes used.
[0007] When using lightweight metals such as aluminum alloys, the curved plate, output flange, and carrier member slide against each other. To protect against this, a sliding protection member is interposed between the curved plate, output flange, and carrier member.
[0008] However, as mentioned above, lighter metals are used for the purpose of weight reduction, so there is a desire to minimize the weight increase caused by adding sliding protection members. On the other hand, for the reasons mentioned above, removing the sliding protection members would reduce the strength of the cycloidal reducer.
[0009] Furthermore, as shown in Figures 4 and 5, the cage-shaped cycloidal reducer transmits output to the output flange 114 via the output pin 113 while a pair of curved plates 111a and 111b revolve around the input shaft 116 and rotate on their own while being phase-shifted from each other.
[0010] With this structure, since the output pin 113 penetrates the output flange 114 and the carrier member 115, the moment acting on the curved plate 111b located on the carrier member 115 side is greater than that acting on the curved plate 111a located on the output flange 114 side. As shown in Figure 5, the carrier member 115 side of the output pin 113 bends, and as a result, a pressing force is constantly generated on the carrier member 115.
[0011] Such pressing forces hinder the smooth rotation of the curved plates 111a and 111b, causing wear and damage to the components. Furthermore, the interposition of the aforementioned sliding protective member increases the length of the output pin 113 by the length of the sliding protective member, which reduces the rigidity of the cage shape. To maintain rigidity, the diameter of the output pin 113 must be increased or the fitting length increased, leading to problems such as an increase in the size and weight of the cycloidal reducer.
[0012] The present invention was made to solve the above problems, and aims to provide a cycloidal speed reducer that can minimize weight increase even when a lightweight metal such as an aluminum alloy is used to reduce the weight of the speed reducer, and when a sliding protective member is used to prevent sliding wear between members that slide in contact with each other, and also enables miniaturization of the cycloidal speed reducer and suppression of weight increase without increasing the diameter of the output pin or the fitting length, even when a sliding protective member is interposed. [Means for solving the problem]
[0013] The cycloidal speed reducer according to the present invention, which solves the above problems, comprises: a plurality of curved plates having external teeth formed thereon and a rotation center eccentric with respect to the input shaft; a fixed gear having internal teeth that mesh with the external teeth and causing the curved plates to rotate on their own axis while revolving in accordance with the rotation of the input shaft; a plurality of output pins disposed to penetrate the pair of curved plates in the axial direction; an output flange into which one end of the output pins is inserted; and a carrier member into which the other end of the output pins is inserted, wherein the cycloidal speed reducer comprises: a first sliding protective member disposed between the curved plates and the output flange; and a second sliding protective member disposed between the curved plates and the carrier member, wherein the first sliding protective member and the second sliding protective member are made of a material with higher hardness than the output flange and the carrier member, and the axial thickness of the first sliding protective member is formed to be thinner than the axial thickness of the second sliding protective member.
[0014] Furthermore, the cycloidal speed reducer according to the present invention, which solves the above problems, comprises: a plurality of curved plates having external teeth formed on them and a rotation center eccentric with respect to the input shaft; a fixed gear having internal teeth that mesh with the external teeth and causing the curved plates to rotate on their own axis while revolving in accordance with the rotation of the input shaft; a plurality of output pins disposed to penetrate the pair of curved plates in the axial direction; an output flange into which one end of the output pins is inserted; and a carrier member into which the other end of the output pins is inserted, wherein the cycloidal speed reducer comprises: a first sliding protective member disposed between the curved plates and the output flanges; and a second sliding protective member disposed between the curved plates and the carrier member, wherein the insertion length of one end of the output pins into the output flanges is longer than the insertion length of the other end of the output pins into the carrier member. [Effects of the Invention]
[0015] The cycloidal speed reducer according to the present invention comprises a first sliding protective member positioned between the curved plate and the output flange, and a second sliding protective member positioned between the curved plate and the carrier member. Since the first and second sliding protective members are made of a material with higher hardness than the output flange and the carrier member, even when lightweight metals such as aluminum alloy are used for the output flange and the carrier member, the cycloidal speed reducer can be made smaller and lighter while maintaining the necessary rigidity by interposing sliding protective members made of a higher hardness material. Furthermore, since the axial thickness of the first sliding protective member is formed to be thinner than the axial thickness of the second sliding protective member, the cycloidal speed reducer can be made larger and heavier. [Brief explanation of the drawing]
[0016] [Figure 1] A cross-sectional view of an actuator equipped with a cycloidal speed reducer according to an embodiment of the present invention. [Figure 2] Enlarged view of section A in Figure 1. [Figure 3] An exploded perspective view of a cycloidal speed reducer according to an embodiment of the present invention. [Figure 4]A diagram for explaining the operation of a conventional cycloid speed reducer. [Figure 5] Cross-sectional view taken along line B-B in Fig. 4.
Embodiments for Carrying Out the Invention
[0017] Hereinafter, embodiments of a cycloid speed reducer according to the present invention will be described with reference to the drawings. Note that the following embodiments do not limit the invention according to each claim, and not all combinations of features described in the embodiments are essential for the solution means of the invention.
[0018] Fig. 1 is a cross-sectional view of an actuator including a cycloid speed reducer according to an embodiment of the present invention, Fig. 2 is an enlarged view of part A in Fig. 1, and Fig. 3 is an exploded perspective view of a cycloid speed reducer according to an embodiment of the present invention.
[0019] As shown in Fig. 1, the cycloid speed reducer 10 according to the present embodiment is suitably used for an actuator 1 or the like that decelerates and outputs the driving force of the motor 2. The actuator 1 is preferably employed, for example, at indirect drive locations of the legs or arms of a humanoid robot.
[0020] The actuator 1 includes a motor 2 that is supplied with power from a power source (not shown), and the rotation shaft of the motor 2 is connected to the input shaft 16 of the cycloid speed reducer 10.
[0021] As shown in FIGS. 2 and 3, the cycloid speed reducer 10 according to the present embodiment includes an input shaft 16 having a pair of eccentric shafts 17a and 17b formed on the outer periphery thereof and arranged with a 180° phase shift from each other, a pair of curve plates 11a and 11b that mesh with the eccentric shafts 17a and 17b and have external teeth formed on the outer peripheral surface, a plurality of output pins 13 inserted into output pin bearings 33 inserted into output pin holes 18a and 18b formed along the circumferential direction in the curve plates 11a and 11b, a fixed gear 12 formed with internal teeth that mesh with the external teeth of the curve plates 11a and 11b and that revolves and rotates while following the rotation of the input shaft 16, an output flange 14 into which one end of the output pin 13 penetrates, and a carrier member 15 into which the other end of the output pin 13 penetrates.
[0022] Further, a first sliding protection member 21 is disposed between the curve plate 11a disposed on the output flange 14 side and the output flange 14, and a second sliding protection member 22 is disposed between the curve plate 11b on the carrier member 15 side and the carrier member 15.
[0023] The internal teeth 12a of the fixed gear 12 are preferably formed in a pin shape having outer rollers. The internal teeth 12a are in contact with the external teeth of the curve plates 11a and 11b, and by providing the outer rollers, the rotation and revolution of the curve plates 11a and 11b can be smoothly guided.
[0024] As shown in FIG. 3, the pair of curve plates 11a and 11b are arranged so as to overlap each other in the axial direction, and are formed in a disk shape having external teeth on the outer peripheral portion. The external teeth formed on the outer periphery of the curve plates 11a and 11b are preferably formed in a curve such as a trochoid. Further, the curve plates 11a and 11b are formed with the output pin holes 18a and 18b arranged in the circumferential direction described above and an input shaft hole 19 through which the input shaft 16 is inserted.
[0025] Output pin bearings 33 are rotatably arranged along the inner periphery of the output pin holes 18a and 18b in the output pin holes 18a and 18b. Further, output pins 13 are inserted into the output pin bearings 33.
[0026] The output flange 14 is a component that reduces the rotation of the input shaft 16 by the revolution and rotation of the curved plates 11a and 11b and outputs the result. The carrier member 15 holds the curved plates 11a and 11b axially between itself and the output flange 14, forming a cage shape and ensuring the rigidity of the cycloidal reducer 10 according to this embodiment. The output flange 14 and the carrier member 15 are made of lightweight metals such as aluminum alloy for the purpose of reducing weight.
[0027] In conventional cycloidal speed reducers, power to the curved plate is transmitted through output pins, but the force applied to the output pins is heavily biased due to the phase relationship of the gears. However, by configuring the cycloidal speed reducer 10 according to this embodiment in a cage shape, the force bending the output pins 13 in the rotational direction is distributed, preventing excessive bending of specific output pins and thus suppressing the aforementioned bias. Furthermore, the output flange 14 and carrier member 15 may be made of low-density iron-based materials such as magnesium alloy or titanium, in addition to the aluminum alloy mentioned above, or materials that have lower surface hardness than iron-based materials but a superior strength / weight ratio. It is also possible to use synthetic resin materials since the sliding parts are covered.
[0028] The first sliding protective member 21 is an annular member formed in a disc shape corresponding to the end face shape of the output flange 14, with multiple through holes 23 formed along the circumferential direction through which the output pin 13 is inserted, and a central hole 24 formed in the center through which the input shaft 16 can be inserted.
[0029] The second sliding protection member 22 is a ring member attached according to the output pin 13, and is press-fitted into the carrier member 15 at the position where the output pin 13 is inserted.
[0030] As shown in Figure 2, the axial thickness of the first sliding protective member 21 is formed to be thinner than the axial thickness of the second sliding protective member 22, and the penetration length L1 of the output pin 13 into the output flange 14 is longer than the penetration length L2 of the output pin 13 into the carrier member 15.
[0031] The first sliding protective member 21 and the second sliding protective member 22 are made of a material with higher hardness than the output flange 14 and the carrier member 15, and for example, hardened iron-based materials (such as SK material or SUJ material) are preferably used. In addition to hardened iron-based materials, any material that is relatively stronger against sliding than the constituent materials such as the carrier member 15 can be used, and the carrier member 15 may be made of synthetic resin and an oil-less sliding material may be embedded in it.
[0032] Thus, according to the cycloidal reducer 10 of this embodiment, since the first sliding protection member 21 and the second sliding protection member 22 are arranged between the output flange 14 and the carrier member 15 and the curved plates 11a and 11b, the output flange 14 and the carrier member 15 can be made of a lightweight metal such as an aluminum alloy, and the cycloidal reducer 10 of this embodiment can be made smaller and lighter.
[0033] Furthermore, since the first sliding protection member 21 is formed thinner than the second sliding protection member 22, by making the second sliding protection member 22 on the carrier member 15 side, which receives a larger bending moment, thicker to ensure rigidity, and by making the first sliding protection member 21 lighter, the cycloidal reducer 10 according to this embodiment can be made smaller and lighter.
[0034] Furthermore, by making the first sliding protective member 21 thin, the distance between the output flange 14 and the carrier member 15 can be shortened, thereby reducing the bending moment received by the output pin 13, and increasing the rigidity of the cycloidal reducer 10 according to this embodiment.
[0035] Furthermore, since the penetration length of the output pin 13 is formed such that the penetration length L1 into the output flange 14 is longer than the penetration length L2 into the carrier member 15, it is possible to reduce the weight of the cycloidal reducer 10 according to this embodiment without reducing rigidity and strength.
[0036] The cycloidal reducer 10 according to this embodiment has been described in the case where a motor is attached to the input shaft 16, but the power source attached to the input shaft 16 is not limited to a motor, and various conventionally known power sources can be used. Furthermore, the cycloidal reducer 10 according to this embodiment has been described in the case where a pair of curved plates 11a and 11b are provided, but the number of curved plates is not limited to one pair, for example, three curved plates may be used and arranged with a phase difference of 120° between each curved plate. It is clear from the description of the claims that such modified or improved forms may also be included in the technical scope of the present invention. [Explanation of Symbols]
[0037] 1 Actuator, 10 Cycloidal reducer, 11a, 11b Curved plates, 12 Fixed gear, 13 Output pin, 14 Output flange, 15 Carrier member, 16 Input shaft, 21 First sliding protective member, 22 Second sliding protective member, L1, L2 Penetration length.
Claims
1. Multiple curved plates having external teeth formed and a rotation center eccentric with respect to the input axis, A fixed gear having internal teeth that mesh with the external teeth, which causes the curved plate to revolve and rotate in accordance with the rotation of the input shaft, Multiple output pins are arranged to penetrate the pair of curved plates in the axial direction, An output flange into which one end of the output pin is inserted, A cycloidal reducer comprising a carrier member into which the other end of the output pin is inserted, A first sliding protective member is positioned between the curved plate and the output flange, The system comprises a second sliding protective member positioned between the curved plate and the carrier member, The first sliding protective member and the second sliding protective member are made of a material with higher hardness than the output flange and the carrier member. A cycloidal speed reducer characterized in that the axial thickness of the first sliding protective member is formed to be thinner than the axial thickness of the second sliding protective member.
2. In the cycloidal speed reducer according to claim 1, The cycloidal speed reducer is characterized in that the first sliding protective member is formed as an annular member corresponding to the axial end face of the curved plate, and has a plurality of insertion holes through which the output pin can be inserted.
3. In the cycloidal speed reducer according to claim 1, The cycloidal speed reducer is characterized in that the second sliding protective member consists of a plurality of ring members inserted around the outer circumference of each of the output pins.
4. In the cycloidal speed reducer according to claim 1, The cycloidal speed reducer is characterized in that the output pins are arranged at predetermined intervals along the circumferential direction of the curved plate.
5. In the cycloidal speed reducer according to claim 1, A cycloidal speed reducer characterized in that the output pin is assembled to the curved plate via a bearing member.
6. Multiple curved plates having external teeth formed and a rotation center eccentric with respect to the input axis, A fixed gear having internal teeth that mesh with the external teeth, which causes the curved plate to revolve and rotate in accordance with the rotation of the input shaft, Multiple output pins are arranged to penetrate the pair of curved plates in the axial direction, An output flange into which one end of the output pin is inserted, A cycloidal reducer comprising a carrier member into which the other end of the output pin is inserted, A first sliding protective member is positioned between the curved plate and the output flange, The system comprises a second sliding protective member positioned between the curved plate and the carrier member, A cycloidal speed reducer characterized in that the penetration length of one end of the output pin into the output flange is longer than the penetration length of the other end of the output pin into the carrier member.