Speed ​​reduction device, assembly method of joint structure of robot

Abstract

The object of the present invention is to provide a reduction gear capable of enlarging a hollow portion. The reduction gear (100) comprises a reduction gear (10) having a hollow portion (H) penetrating axially in the center portion and a motor coupling (42) disposed between the reduction gear (10) and a motor (40). In the reduction gear, the reduction gear (10) comprises a housing (22), a wheel carrier (18) disposed inside the housing (22) and rotating relative to the housing (22), an input gear (36) transmitting the rotation of the motor (40), and a center gear (38) meshing with the input gear (36) and surrounding the hollow portion (H). The motor coupling (42) and the wheel carrier (18) are locked and engaged by a locking portion (J1), and are connected together by a connecting member, and the locking portion (J1) is arranged at a position radially more outward than the connecting member.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2020-036815 filed on March 4, 2020. The entire contents of the Japanese Patent Application are incorporated herein by reference. Technical Field

[0002] The invention relates to a speed reducing device and a joint structure of a manipulator. Background Art

[0003] A reducer having a hollow portion that rotates about a central axis is known. The present applicant disclosed a geared motor consisting of a motor and an internally connected swing meshing planetary gear reducer through patent document 1. In the geared motor, a hollow portion for passing cables and the like is provided in the center of the reducer, and a motor is provided on the upper surface side of the reducer. The rotation of a pinion gear of a motor shaft disposed at a position offset from the central axis of the hollow portion is transmitted to an input gear of the reducer. The pinion gear and the input gear constitute a primary reduction portion of the reducer.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2008-039161

[0005] In the hollow part of the speed reducer, for example, a cable or a pipe for conveying air (hereinafter referred to as "wiring") is passed through. In order to allow room for the wiring to pass through, the diameter of the hollow part is expected to be large. However, in the gear transmission motor described in Patent Document 1, if the diameter of the hollow part becomes large, the motor arranged on the upper surface side of the speed reducer may interfere with the hollow part, and thus the size of the hollow part is limited. Summary of the invention

[0006] The present invention has been made in view of such a problem, and an object of the present invention is to provide a reduction gear device capable of enlarging a hollow portion.

[0007] In order to solve the above-mentioned problems, a reduction gear according to an embodiment of the present invention comprises a reduction gear having a hollow portion penetrating in the axial direction in the central portion and a motor coupling arranged between the reduction gear and the motor, wherein the reduction gear comprises a housing, a wheel carrier arranged inside the housing and rotating relative to the housing, an input gear to which the rotation of the motor is transmitted, and a central gear meshing with the input gear and surrounding the hollow portion. The motor coupling and the wheel carrier are locked and engaged by a locking portion, and are connected together by a connecting member, and the locking portion is arranged at a position radially more outward than the connecting member.

[0008] In addition, any combination of the above-mentioned constituent elements or any form in which constituent elements or expressions of the present invention in methods, systems, etc. are replaced with each other may also be practiced as additional modes of the present invention.

[0009] According to the present invention, a reduction gear device capable of increasing the size of a hollow portion is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a plan view showing the reduction gear transmission according to the first embodiment.

[0011] Figure 2 Yes means Figure 1 A side sectional view of a reduction gear unit.

[0012] Figure 3 It is a plan view showing a reduction gear transmission according to a second embodiment.

[0013] Figure 4 Yes means Figure 3 A side sectional view of a reduction gear unit.

[0014] Figure 5 It is a side view showing the joint structure of the manipulator according to the third embodiment.

[0015] Figure 6 It is a side cross-sectional view showing a reduction gear transmission of a comparative example.

[0016] In the figure: J1, J2, J3-locking part, 10-reducing machine, 10j-lubricant, B12-bolt, 17-wheel frame body, 19-auxiliary wheel frame, 22-housing, 36-input gear, 38-center gear, 40-motor, 42-motor connector, 50-first sealing part, 50p-O-ring, 52-second sealing part, 52p-sealing gasket, 54p-O-ring, 74, 76-bolt, 100, 200-reducing device, 300-joint structure, 302-first component, 304-second component. DETAILED DESCRIPTION

[0017] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the embodiments and modified examples, the same or equivalent components and parts are marked with the same symbols, and repeated descriptions are appropriately omitted. In addition, for ease of understanding, the size of the components in each figure is appropriately enlarged or reduced. In addition, in each figure, a part of the components that are not important for the description of the embodiment is omitted.

[0018] Furthermore, terms including numbers such as 1 and 2 are used to describe various constituent elements, but such terms are only used to distinguish one constituent element from other constituent elements, and such terms are not used to limit the constituent elements.

[0019] [First embodiment]

[0020] Hereinafter, the structure of the reduction gear device 100 according to the first embodiment of the present invention will be described with reference to the drawings. Figure 1It is a plan view schematically showing the reduction gear transmission 100 according to the present embodiment. Figure 2 1 is a cross-sectional view showing a reduction gear device 100 according to the present embodiment when viewed from the side. Figure 2 Indicates along Figure 1 The use of the reduction gear 100 is not limited, but in this example, the reduction gear 100 can be used for joints of a multi-joint robot.

[0021] The reduction gear 100 includes a reduction gear 10 and a motor coupling 42 disposed between the reduction gear 10 and the motor 40. The reduction gear 10 has a hollow portion H extending axially through the center portion. The hollow portion H is provided in the cylindrical member 28. The rotation from the motor 40 mounted on the motor coupling 42 is input to the reduction gear 10, and the reduction gear 10 reduces the input rotation and rotates the motor coupling 42, a driven member connected to the motor coupling 42 (for example, an arm member of a robot), and the cylindrical member 28.

[0022] Hereinafter, the direction along the central axis La of the cylindrical member 28 is referred to as the "axial direction", and the circumferential direction and radial direction of a circle centered on the central axis La are referred to as the "circumferential direction" and the "radial direction", respectively. Also, hereinafter, for the sake of convenience, one side in the axial direction (the upper side in the figure) is referred to as the input side, and the other side in the circumferential direction (the lower side in the figure) is referred to as the opposite input side. The motor adapter 42 is arranged on the input side of the speed reducer 10.

[0023] First, the speed reducer 10 will be described. Figure 2 The reducer 10 mainly includes: an input shaft 12; an external gear 14; an internal gear 16; wheel carriers 18, 20; a housing 22; main bearings 24, 26; a cylindrical component 28; an inner pin 32; an input gear 36; and a center gear 38. The reducer 10 of this embodiment is a center crank type reducer in which the input shaft 12 is arranged on the same axis as the center axis La of the internal gear 16. The reducer 10 has a hollow portion H extending axially through the center portion. The hollow portion H is provided in the cylindrical component 28. The wheel carriers 18, 20 include a first wheel carrier 18 arranged on the input side side of the external gear 14 and a second wheel carrier 20 arranged on the opposite input side of the external gear 14.

[0024] The housing 22 constitutes the outer shell of the speed reducer 10. The wheel carriers 18 and 20 are arranged on the inner side of the housing 22 and rotate relative to the housing 22. The input gear 36 is connected to the motor shaft 40s of the motor 40 so as to rotate integrally with the motor 40. The center gear 38 meshes with the input gear 36. The center gear 38 surrounds the hollow portion H and the cylindrical member 28. The input shaft 12 is a hollow cylindrical member that surrounds the cylindrical member 28 in a manner that there is a gap between it and the cylindrical member 28, and the center gear 38 is connected to the end on the input side thereof by a connecting member such as a bolt B12. The input gear 36 and the center gear 38 constitute a primary transmission, which changes the rotation of the motor 40 at a specified gear ratio and transmits it to the input shaft 12. The following is a detailed description.

[0025] The input shaft 12 has a plurality of eccentric portions 12a for oscillating the external gear 14. In this example, the input shaft 12 has two eccentric portions 12a that are 180 degrees out of phase with each other. Both ends of the input shaft 12 are supported by the carriers 18 and 20 via input shaft bearings 34.

[0026] The external gear 14 is rotatably supported by the corresponding input shaft 12 via an eccentric bearing 30. A plurality of inner pin holes 14h are formed at positions offset from the axis of the external gear 14. The inner pins 32 are inserted into the inner pin holes 14h. The teeth formed on the outer periphery of the external gear 14 rotate while meshing with the teeth of the internal gear 16, so that the external gear 14 swings.

[0027] The internal gear 16 of the present embodiment is formed integrally with the housing 22 at the inner peripheral portion of the housing 22. The number of teeth of the internal gear 16 is one more than the number of external teeth of the external gear 14.

[0028] The first carrier 18 and the second carrier 20 are rotatably supported by the housing 22 via the main bearing 24 and the main bearing 26 . The first carrier 18 and the second carrier 20 support the input shaft 12 via the input shaft bearing 34 .

[0029] The first carrier 18 and the second carrier 20 are connected to each other via the inner pins 32. The inner pins 32 penetrate the inner pin holes 14h of the external gear 14 in the axial direction at positions offset in the radial direction from the axial center of the external gear 14.

[0030] One of the wheel carriers 18, 20 and the housing 22 functions as an output component that outputs rotational power to the driven device, and the other functions as a fixed component fixed to an external component for supporting the reducer 10. In the present embodiment, the output components are the first wheel carrier 18 and the second wheel carrier 20, and the fixed component is the housing 22.

[0031] The main bearings 24 and 26 include a first main bearing 24 disposed on the input side of the external gear 14 and a second main bearing 26 disposed on the opposite side of the input of the external gear 14. The main bearings 24 and 26 are disposed between the first wheel carrier 18 and the housing 22 and between the second wheel carrier 20 and the housing 22, respectively. The outer rings of the main bearings 24 and 26 are supported by the housing 22. The inner rings of the main bearings 24 and 26 are formed integrally with the wheel carriers 18 and 20.

[0032] In this example, ten inner pins 32 are arranged at intervals of 36° in the circumferential direction. Figure 2 Only one inner pin 32 is shown in the figure. The input side of the inner pin 32 is fixed to the first wheel frame 18, and the opposite side of the input is fixed to the second wheel frame 20. The inner pin 32 connects the first wheel frame 18 and the second wheel frame 20. Figure 2 In the example of , the inner pin 32 is formed integrally with the first wheel frame 18, and the opposite side of the input is fixed to the second wheel frame 20 by a bolt B20. A sleeve 32s is provided on the outer periphery of the inner pin 32. The inner pin 32 is inserted into the inner pin hole 14h with a gap therebetween. The inner pin 32 abuts against a part of the inner pin hole 14h via the sleeve 32s. The inner pin 32 restricts the self-rotation of the outer gear 14 and only allows it to swing.

[0033] The input gear 36 and the sun gear 38 may be spur gears or helical gears.

[0034] The motor 40 may be any motor that can input a rotational driving force to the speed reducer 10, and motors based on various principles may be used. In this example, the motor 40 is a servo motor.

[0035] The motor adapter 42 has a generally disk-like shape covering the reducer 10 when viewed from above. The motor adapter 42 has a motor support portion 42m that supports the motor 40 in a portion in the circumferential direction. The motor support portion 42m has a fitting portion 42n that fits with the input side end portion of the motor 40 and a flange 42f for connecting the motor 40. When viewed from above, the flange 42f has a generally rectangular shape, and a portion of its outer circumference protrudes toward the center of the hollow portion H. When viewed from above, the hollow portion H has a size that does not interfere with the flange 42f.

[0036] The cylindrical member 28 has a cylindrical portion 28s surrounding the hollow portion H and a flange portion 28f protruding radially outward from the end of the cylindrical portion 28s on the opposite side of the input. The cylindrical portion 28s is surrounded by the input shaft 12 via a gap. A portion of the cylindrical portion 28s is locked and fitted with the second wheel frame 20. An O-ring 28q is provided between the cylindrical portion 28s and the second wheel frame 20. The flange portion 28f is fixed to the end surface of the second wheel frame 20 on the opposite side of the input by a fastener such as a bolt B28. The end of the input side of the cylindrical portion 28s is surrounded by the motor connector 42 via an oil seal F28.

[0037] The housing 22 is a hollow cylindrical member surrounding the wheel carriers 18 and 20, and has a housing flange 22f protruding radially outward. The housing flange 22f is provided with a flange hole 22h penetrating in the axial direction. The housing flange 22f is connected to an external member.

[0038] Next, the characteristic structure of this embodiment will be described. Here, first, a comparative example will be described. This comparative example was created by the inventors in the process of creating this embodiment. Figure 6 2 is a side cross-sectional view showing a reduction gear device 500 according to a comparative example. Figure 6 In order to facilitate understanding, the motor coupling 42, the cylindrical member 28, the input gear 36, the sun gear 38, the input shaft 12, the first carrier 18 and the bolt 74 are shown, and other members are omitted. In the present embodiment and the comparative example, the bolt 74 is exemplified as the connecting member.

[0039] The main differences between this comparative example and this embodiment are the shapes of the motor connector 42 and the first wheel frame 18, the locking portion of the first wheel frame 18, and the positional relationship between the O-ring and the bolt 74, while the other structures are roughly the same as those of the present embodiment. Therefore, repeated descriptions are omitted and the differences are described. In this comparative example, the motor connector 42 and the first wheel frame 18 are locked and engaged through the locking portion J3, and are connected together by the bolt 74. The locking portion J3 is arranged at a position closer to the radial inside than the bolt 74. In this example, the bolt 74 is a bolt that passes through the motor connector 42 from the input side and is threadedly engaged with the first wheel frame 18. In addition, the O-ring 50p that prevents the lubricant from leaking from between the motor connector and the first wheel frame 18 is also arranged at a position closer to the radial inside than the bolt 74.

[0040] Next, the locking portion J3 is described. The first wheel frame 18 is provided with an annular protrusion 18j protruding toward the input side at the inner circumference of the end face on the input side. The motor adapter 42 has a cover body portion 42b covering the input side end face of the first wheel frame 18, and a central hole 42h penetrating along the axial direction is provided in the center of the cover body portion 42b. The outer circumferential surface 18k of the annular protrusion 18j and the inner circumferential surface of the central hole 42h are locked and fitted with each other to form the locking portion J3.

[0041] exist Figure 6In the example of , the flange 42f of the motor adapter 42 protrudes greatly toward the input side of the cylindrical member 28 in the radial direction. At this time, in order to avoid interference between the motor adapter 42 and the wiring passing through the hollow portion H, the hollow portion H of the cylindrical member 28 needs to be reduced as shown by the dotted line. In order to reduce the protrusion of the motor adapter 42, it is conceivable to increase the center distance X3 between the input gear 36 and the center gear 38. However, if the center distance X3 is increased while maintaining the gear ratio between them, the outer diameter of the center gear 38 will exceed the inner diameter of the center hole 42h of the cover body 42b. If the center gear 38 becomes too large, the center hole 42h cannot pass through the outside of the center gear 38, so the motor adapter 42 cannot be connected to the first wheel frame 18. In addition, the radial inner space of the bolt 74 is also limited, so moving the lock portion J3 and the O-ring 50p radially outward to expand the center hole 42h is also limited. Therefore, in the comparative example, the size of the hollow portion H is limited.

[0042] Based on the description of the comparative example, we return to the description of this embodiment. Figure 2 As shown, in this embodiment, the motor adapter 42 and the first wheel frame 18 are locked and fitted by the locking portion J1, and the motor adapter 42 and the first wheel frame 18 are connected together by the bolt 74. The locking portion J1 is provided at a position radially outwardly of the bolt 74. In this example, the bolt 74 is a bolt that penetrates the motor adapter 42 from the input side and is screwed with the first wheel frame 18.

[0043] Next, the locking portion J1 will be described. The first wheel frame 18 is provided with an annular protrusion 18m protruding toward the input side on the outer peripheral portion of the input side end face. The motor connector 42 has a cover portion 42b covering the input side end face of the first wheel frame 18. An annular recess 42c that surrounds the center axis La is provided on the surface of the cover portion 42b on the opposite side of the input. The annular recess 42c has an inner circumferential side annular wall surface 42d extending in the axial direction on the inner circumferential side. The inner circumferential surface 18n of the annular protrusion 18m and the inner circumferential side annular wall surface 42d of the annular recess 42c are locked and fitted with each other to form the locking portion J1.

[0044] According to the structure of this embodiment, Figure 2 As shown, the locking portion J1 is arranged at a position radially outward from the bolt 74, so that the inner diameter of the center hole 42h can be made larger than that of the comparative example. Therefore, even if the outer diameter of the center gear 38 is increased, the center hole 42h can pass through the outside thereof, so that the center distance X1 between the input gear 36 and the center gear 38 can be made larger than that of the comparative example. As a result, the motor coupling 42 can be arranged radially outward in a manner that the motor coupling 42 and the hollow portion H do not overlap when viewed from the axial direction. At this time, interference between the motor coupling 42 and the hollow portion H can be avoided, and the hollow portion H of the cylindrical member 28 can be made larger than that of the comparative example.

[0045] Next, refer to Figure 2 The sealing portion is described. Lubricant 10j, which is mainly used to lubricate the gears, is injected into the interior of the reduction gear 100. Therefore, the reduction gear 100 has a first sealing portion 50 that prevents the lubricant 10j from leaking from between the motor coupling 42 and the first wheel frame 18, and a second sealing portion 52 that prevents the lubricant 10j from leaking from between the motor coupling 42 and the bolt 74. At this time, the leakage of the lubricant 10j in each part can be effectively reduced.

[0046] In this embodiment, the first sealing portion 50 includes an O-ring 50p disposed at a position radially outward from the bolt 74. The O-ring 50p is accommodated in a circumferential groove 18p provided on the end surface of the first wheel frame 18, and the motor adapter 42 and the O-ring 50p are closely fitted to perform a sealing function. At this time, the leakage of the lubricant 10j between the motor adapter 42 and the first wheel frame 18 can be reduced by a low-cost structure.

[0047] In the present embodiment, the second sealing portion 52 includes a sealing gasket 52p disposed between the bolt 74 and the motor adapter 42. The sealing gasket 52p has a washer-like shape disposed between the head of the bolt 74 and the motor adapter 42. As an example, the sealing gasket 52p can be composed of a metal retainer and a rubber ring mechanically connected to the inner periphery of the metal retainer. In this case, the leakage of the lubricant 10j between the motor adapter 42 and the bolt 74 can be reduced by a low-cost structure.

[0048] In the present embodiment, the first sealing portion 50 (O-ring 50p) is disposed at a position radially outward from the bolt 74, so that the inner diameter of the center hole 42h can be made larger than that of the comparative example. Therefore, even if the outer diameter of the center gear 38 is increased, the center hole 42h can pass through the outside thereof, so that the center distance X1 between the input gear 36 and the center gear 38 can be made larger than that of the comparative example. As a result, the motor adapter 42 can be arranged radially outward in a manner that the motor adapter 42 and the hollow portion H do not overlap when viewed from the axial direction. At this time, interference between the motor adapter 42 and the hollow portion H can be avoided, and the hollow portion H of the cylindrical member 28 can be made larger than that of the comparative example. In addition, by disposing the first sealing portion 50 (O-ring 50p) at a position radially outward from the bolt 74, the lubricant 10j may leak from the insertion hole of the bolt 74, but by disposing the second sealing portion 52 (sealing gasket 52p), the leakage can be prevented.

[0049] In addition, from the viewpoint of increasing the inner diameter of the central hole 42h and the inner diameter of the hollow portion H, it is preferred that both the lock portion J1 and the first sealing portion 50 are disposed radially outward from the bolt 74, but the present invention is not limited thereto, as long as at least one of the lock portion J1 and the first sealing portion 50 is disposed radially outward from the bolt 74. In the case where only one of the lock portion J1 and the first sealing portion 50 is disposed radially outward from the bolt 74, the inner diameter of the hollow portion H can be made larger than that of the comparative example.

[0050] Next, the operation of the reduction gear 100 will be described. If the rotation is transmitted from the motor 40 to the input shaft 12 via the input gear 36 and the center gear 38, the eccentric portion 12a of the input shaft 12 rotates around the rotation center line passing through the input shaft 12, thereby causing the external gear 14 to oscillate. If the external gear 14 oscillates, the meshing positions of the external gear 14 and the internal gear 16 are sequentially shifted. As a result, for each rotation of the input shaft 12, one of the external gear 14 and the internal gear 16 rotates by an amount corresponding to the difference in the number of teeth between the external gear 14 and the internal gear 16. In the present embodiment, the external gear 14 rotates, and the rotation is transmitted to the first wheel frame 18 and the second wheel frame 20 via the inner pin 32, and the decelerated rotation is output from the first wheel frame 18 and the second wheel frame 20. As the first wheel frame 18 rotates, the motor coupling 42 connected to the first wheel frame 18 and the driven components connected to the motor coupling rotate. The cylindrical member 28 connected to the second carrier 20 rotates as the second carrier 20 rotates. The above is the description of the first embodiment.

[0051] [Second embodiment]

[0052] Next, refer to Figure 3 and Figure 4 , the structure of the reduction gear device 200 according to the second embodiment of the present invention will be described. Figure 3 It is a plan view schematically showing the reduction gear transmission 200 according to the present embodiment. Figure 4 It is a cross-sectional view showing the reduction gear transmission 200 according to the present embodiment when viewed from the side.

[0053] The second embodiment differs from the first embodiment in that it has an auxiliary wheel frame and the structure of the lock portion and the function of the connecting member are different, and the other structures are the same as those of the first embodiment. Here, repeated descriptions are omitted and the differences are mainly described.

[0054] In the description of the first embodiment, an example is shown in which the first wheel frame 18 is composed of one component, but the first wheel frame 18 may be composed of a plurality of components. In this case, even a complex shape can be easily processed by dividing it into a plurality of components. As an example, the first wheel frame 18 of the present embodiment has a wheel frame body 17 and an auxiliary wheel frame 19 arranged between the wheel frame body 17 and the motor coupling 42. The auxiliary wheel frame 19 has a substantially circular plate shape and also functions as a cover member covering the opposite side of the input of the motor coupling 42. The surface of the auxiliary wheel frame 19 on the opposite side of the motor coupling 42 abuts against the wheel frame body 17 in the axial direction.

[0055] The bolt 74 of the present embodiment is a wheel frame connecting component that connects the wheel frame main body 17 and the auxiliary wheel frame 19. Next, the first locking portion J1 will be described. The motor connector 42 and the auxiliary wheel frame 19 are locked and fitted through the first locking portion J1. The auxiliary wheel frame 19 is provided with a circumferential protrusion 19j protruding toward the input side on the end face on the input side. The outer circumferential surface 19k of the circumferential protrusion 19j and the inner circumferential surface of the central hole 42h are locked and fitted with each other to form the first locking portion J1.

[0056] The lock portion J1 is provided at a position radially outward of the auxiliary wheel frame 19 relative to the bolt 74. Figure 4 As shown, the locking portion J1 is provided at a position radially outwardly closer to the outside than the bolt 74, so that the inner diameter of the center hole 42h can be made larger than that of the comparative example and the first embodiment. That is, in the present embodiment, by providing an auxiliary wheel frame 19 between the wheel frame body 17 and the motor coupling 42, the auxiliary wheel frame 19 can be connected to the wheel frame body 17 by the bolt 74 before the center gear 38 is mounted on the input shaft 12. Therefore, the inner diameter of the center hole 19h of the auxiliary wheel frame 19 can be smaller than the outer diameter of the center gear 38. That is, when viewed axially, the auxiliary wheel frame 19 and the center gear 38 can overlap. Moreover, by providing the auxiliary wheel frame 19, the inner diameter of the center hole 42h of the motor coupling 42 can be made very large, so that the outer side of the center gear can pass through axially with ease, and as a result, the inner diameter of the hollow portion H can also be increased.

[0057] Next, the second locking portion J2 will be described. The wheel frame body 17 and the auxiliary wheel frame 19 are locked and fitted together through the second locking portion J2. The wheel frame body 17 is provided with an annular protrusion 17j protruding toward the input side on the inner circumference of the end face on the input side. A central hole 19h is provided in the center of the auxiliary wheel frame 19 that penetrates in the axial direction. The outer circumferential surface 17k of the annular protrusion 17j and the inner circumferential surface of the central hole 19h are locked and fitted together to form the second locking portion J2. The locking portion J2 is provided at a position radially more inward than the bolt 74.

[0058] Next, the sealing portion will be described. In addition to the first sealing portion 50 and the second sealing portion 52, the present embodiment also has a third sealing portion (wheel carrier sealing portion) 54 that prevents the lubricant 10j from leaking from between the wheel carrier body 17 and the auxiliary wheel carrier 19. In the present embodiment, the first sealing portion 50 includes an O-ring 50p that is arranged at a position radially more outward than the bolt 74. The O-ring 50p is accommodated in a circumferential groove 19p provided on the end face of the auxiliary wheel carrier 19, and the motor connector 42 and the O-ring 50p are in close contact with each other to perform a sealing function. The second sealing portion 52 includes a sealing gasket 52p that is arranged between the bolt 74 and the auxiliary wheel carrier 19. The third sealing portion 54 includes an O-ring 54p that is arranged at a position radially more outward than the bolt 74. The O-ring 54p is accommodated in a circumferential groove 17p provided on the end face of the wheel carrier body 17, and the auxiliary wheel carrier 19 and the O-ring 54p are in close contact with each other to perform a sealing function. Figure 4 In the example of , the first seal portion 50 is arranged radially outward of the second seal portion 52 and the third seal portion 54 .

[0059] The second embodiment operates in the same manner as the first embodiment, and exhibits the same operational effects as the first embodiment. The above is the description of the second embodiment.

[0060] [Third Embodiment]

[0061] Next, refer to Figure 2 and Figure 5 , the structure of the joint structure 300 of the manipulator involved in the third embodiment of the present invention is described. Figure 5 1 is a side view showing the joint structure 300 of the manipulator involved in the present embodiment. The figure shows the periphery of the joint structure 300. The joint structure 300 of the present embodiment includes a first component 302, a second component 304, and a reduction gear 100 arranged between the first component 302 and the second component 304. In the present embodiment, the first component 302 is a base side arm connected to the base end side of the joint, and the second component 304 is a front side arm connected to the front end side of the joint. The second component 304 rotates in the direction indicated by the arrow E relative to the first component 302.

[0062] like Figure 2 As shown, the reduction gear 100 includes a reduction gear 10 having a hollow portion H extending axially through the center portion thereof, and a motor coupling 42 disposed between the reduction gear 10 and the motor 40. The reduction gear 10 includes a housing 22 and wheel carriers 18 and 20 disposed inside the housing 22 and rotating relative to the housing 22. The description of the first embodiment is applicable to the reduction gear 100.

[0063] The housing flange 22f of the housing 22 is connected to the first component 302 by a first connecting component such as a bolt 76. At least one of the wheel frames 18 and 20 is connected to the second component 304. In the present embodiment, the first wheel frame 18 is connected to the motor connector 42 by a second connecting component such as a bolt 74, and the motor connector 42 is connected to the second component 304 not shown. The joint structure 300 is configured as a structure for performing the tightening work of the bolts 76 and the bolts 74 from the motor 40 side (the first wheel frame 18 side) in the axial direction. According to the third embodiment, the same effect as the first embodiment is exerted. Moreover, the third embodiment can tighten the bolts 76 and the bolts 74 from the same direction, so the operability is high. The above is a description of the third embodiment.

[0064] The examples of the embodiments of the present invention are described in detail above. The embodiments described above are only specific examples of the present invention. The contents of the embodiments are not intended to limit the technical scope of the present invention. Various design changes such as changes, additions, and deletions of constituent elements can be made without departing from the scope of the idea of ​​the invention specified in the technical solution. In the embodiments described above, the contents that can undergo such design changes are described by marking "embodiment" and "implementation method", but this does not mean that design changes are not allowed for contents without such markings. In addition, the hatched lines marked on the cross-sections of the accompanying drawings are not intended to limit the material of the objects marked with hatched lines.

[0065] In the following, a modification example is described. In the drawings and description of the modification example, the same reference numerals are given to the same or equivalent components and parts as those in the embodiment. The description repeated with the embodiment is appropriately omitted, and the structure different from the embodiment is described in detail.

[0066] [Modifications]

[0067] In the description of the embodiment, an example is shown in which the first sealing portion 50 includes an O-ring 50p, the second sealing portion 52 includes a sealing gasket 52p, and the third sealing portion 54 includes an O-ring 54p, but the present invention is not limited thereto, and the sealing portion may adopt various known sealing structures. For example, the sealing portion may be formed by applying a liquid gasket to a corresponding portion such as a portion radially inward of the connecting member between the motor adapter and the wheel carrier.

[0068] In the description of the implementation mode, an example is shown in which the connecting member, the wheel frame connecting member, the first connecting member and the second connecting member are all bolts, but these connecting members can be connecting members as long as they can connect multiple members. Various connecting members other than bolts may be used, such as pins and rivets.

[0069] In the description of the embodiment, an example is shown in which the reduction mechanism of the reducer 10 is a center crank type eccentric oscillating type reducer, but the present invention is not limited to this. The reduction mechanism of the reducer 10 can be any as long as it can reduce the rotation of the motor, for example, a flexure meshing type reducer such as a cylinder type, a cup type, a top hat type, a distributed eccentric oscillating type reducer, or a simple planetary gear type reducer can also be used.

[0070] The above-mentioned modifications also achieve the same effects as those of the embodiment.

[0071] Any combination of the constituent elements and modifications of the above-described embodiments is also effective as an embodiment of the present invention. A new embodiment generated by the combination has the effects of the combined embodiments and modifications.

Claims

1. A reduction gear device, comprising a reduction gear having a hollow portion penetrating in the axial direction at the center thereof and a motor coupling disposed between the reduction gear and the motor, wherein the reduction gear device is characterized in that: The speed reducer comprises a housing, a wheel carrier arranged inside the housing and rotating relative to the housing, an input gear to which the rotation of the motor is transmitted, and a central gear meshing with the input gear and surrounding a hollow portion. The motor adapter and the wheel frame are locked and engaged with each other through a locking part, and are connected together through a connecting member. The locking portion is disposed radially outward of the connecting member. The input gear and the sun gear are located axially outward of a connection surface of the carrier connected to the motor coupling via the connection member.

2. A reduction gear device comprising a reduction gear having a hollow portion penetrating in the axial direction at the center thereof and a motor coupling disposed between the reduction gear and the motor, wherein the reduction gear device is characterized in that: The speed reducer comprises a housing, a wheel carrier arranged inside the housing and rotating relative to the housing, an input gear to which the rotation of the motor is transmitted, and a central gear meshing with the input gear and surrounding a hollow portion. The motor adapter is connected to the wheel frame via a connecting member. The reduction gear further includes a first sealing portion for preventing lubricant from leaking from between the motor adapter and the wheel carrier. The first sealing portion is provided at a position radially outward of the connecting member. The input gear and the sun gear are located axially outward of a connection surface of the carrier connected to the motor coupling via the connection member.

3. The reduction gear device according to claim 1 or 2, characterized in that: The invention further comprises a first sealing portion for preventing the lubricant from leaking from between the motor adapter and the wheel carrier, and a second sealing portion for preventing the lubricant from leaking from between the motor adapter and the connecting member.

4. The reduction gear device according to claim 3, characterized in that: The second sealing portion is a sealing gasket disposed between the bolt as the connecting member and the motor adapter.

5. The reduction gear device according to claim 2, characterized in that: The first sealing portion is an O-ring disposed radially outward of the connecting member.

6. The reduction gear device according to claim 1 or 2, characterized in that: When viewed from the axial direction, the motor adapter does not overlap with the hollow portion.

7. A reduction gear device comprising a reduction gear having a hollow portion penetrating in the axial direction at the center thereof and a motor coupling disposed between the reduction gear and the motor, wherein the reduction gear device is characterized in that: The speed reducer comprises a housing, a wheel carrier arranged inside the housing and rotating relative to the housing, an input gear to which the rotation of the motor is transmitted, a central gear meshing with the input gear and surrounding a hollow portion, and an external gear to which the rotation based on the central gear is transmitted. The wheel carrier comprises a wheel carrier body arranged on a side of the external gear, an auxiliary wheel carrier arranged on the side opposite to the external gear relative to the wheel carrier body in the axial direction and arranged between the wheel carrier body and the motor adapter, and a wheel carrier connecting member connecting the wheel carrier body and the auxiliary wheel carrier. The motor adapter and the auxiliary wheel carrier are locked and fitted together by a locking portion provided at a position radially outward of the wheel carrier connecting member. The locking portion is located radially outward of the outer end of the central gear. The sun gear is located axially outward of a connection surface of the carrier main body connected to the auxiliary carrier via the carrier connection member.

8. The reduction gear device according to claim 7, characterized in that: The inner locking portion of the wheel carrier where the wheel carrier main body and the auxiliary wheel carrier are locked and fitted is provided at a position radially inward of the wheel carrier connecting member.

9. The reduction gear device according to claim 7 or 8, characterized in that: The auxiliary wheel carrier is provided with a wheel carrier seal portion, which prevents the lubricant from leaking from between the wheel carrier body and the auxiliary wheel carrier. The carrier seal portion is provided at a radially outer side than the carrier connecting member.

10. The reduction gear device according to claim 7 or 8, characterized in that: When viewed from the axial direction, the auxiliary wheel carrier overlaps with the sun gear.

11. A joint structure of a robot, comprising a first component, a second component, and the reduction device according to claim 1, 2 or 7 disposed between the first component and the second component.

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