Planetary gear reduction mechanism

Abstract

To provide a planetary gear reduction mechanism which can accurately drive a drive object.SOLUTION: First and second support shaft fixing holes 64a, 64b into which a support shaft 52 for rotatably supporting a planetary gear 50 is fixed are formed at a carrier 60, and a shaft joint 70 is fixed to the carrier 60 by a fixing pin 73 which is fixed to the second support shaft fixing hole 64b. By this constitution, a shaft joint 70 can be accurately fixed to the carrier 60 which is formed with high processing accuracy. Therefore, a planetary gear reduction mechanism 10 which can accurately drive a drive mechanism or the like of a robot being a drive object can be obtained.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a planetary gear reduction mechanism having a plurality of gears. [Background technology]

[0002] For example, Patent Document 1 describes a planetary gear reducer in which a planetary gear mechanism consisting of a sun gear, planetary gears, a carrier, and an internal gear is arranged in two stages in the axial direction, whereby the rotational speed of the motor shaft on the input side is reduced, and a high-torque rotational force is output from the output shaft on the output side. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-172411 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in the above-mentioned Patent Document 1, an output shaft is integrally provided at the rotation center of the carrier, but in order to connect the output shaft and the driven object so as to be able to transmit power, a shaft coupling is required between the output shaft and the driven object. If the mounting accuracy of the shaft coupling to the output shaft is low, a backlash occurs between the shaft coupling and the output shaft, which causes a problem that the driven object cannot be driven with high accuracy.

[0005] An object of the present invention is to provide a planetary gear reduction mechanism capable of driving an object to be driven with high precision. [Means for solving the problem]

[0006] In one aspect of the present invention, a planetary gear reduction mechanism having a plurality of gears comprises an input side rotating body connected to a drive source so as to transmit power, a sun gear provided on the input side rotating body, an internal gear arranged radially outside the sun gear, planetary gears arranged between the sun gear and the internal gear, a planetary carrier that rotatably supports the planetary gears, and an output side rotating body fixed to the planetary carrier and driving an object to be driven, wherein the planetary carrier has a support shaft fixing hole to which a support shaft that rotatably supports the planetary gears is fixed, and the output side rotating body is fixed to the planetary carrier by a fixing member fixed to the support shaft fixing hole. Effect of the Invention

[0007] According to the present invention, it is possible to realize a planetary gear reduction mechanism capable of driving an object to be driven with high precision. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view of the planetary gear reduction mechanism as viewed from the output side. [Diagram 2] FIG. 2 is a perspective view of the planetary gear reduction mechanism as viewed from the input side. [Diagram 3] 2 is a cross-sectional view showing the internal structure of the planetary gear reduction mechanism of FIG. 1. [Figure 4] FIG. 2 is a perspective view showing a pinion gear alone. [Diagram 5] FIG. 2 is a perspective view showing an internal gear alone. [Figure 6] FIG. 2 is a perspective view showing three helical gears. [Figure 7] FIG. 2 is a perspective view showing the carrier alone. [Figure 8] 11 is a perspective view showing an assembly procedure of the carrier assembly. FIG. [Figure 9] 11 is a perspective view showing a procedure for assembling the internal gear to the carrier assembly. FIG. [Figure 10] 10A to 10C are perspective views showing a procedure for assembling a housing body and a ring member. [Figure 11]11 is a perspective view showing an assembly procedure of the pinion gear and the backlash adjusting member. FIG. [Figure 12] 5A to 5C are perspective views showing a procedure for assembling the shaft coupling to the carrier. [Figure 13] 7 is a cross-sectional view corresponding to FIG. 3 and showing a planetary gear reduction mechanism according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Embodiment 1] Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings.

[0010] Figure 1 is an oblique view of the planetary gear reduction mechanism seen from the output side, Figure 2 is an oblique view of the planetary gear reduction mechanism seen from the input side, Figure 3 is a cross-sectional view showing the internal structure of the planetary gear reduction mechanism of Figure 1, Figure 4 is an oblique view of the pinion gear alone, Figure 5 is an oblique view of the internal gear alone, Figure 6 is an oblique view of three helical gears, and Figure 7 is an oblique view of the carrier alone.

[0011] [Outline of planetary gear reduction mechanism] 1 to 3 is used, for example, to drive the joints of a robot. An electric motor (not shown), which is a drive source, is provided on the input side (lower side in the figures) of the planetary gear reduction mechanism 10 in a power-transmittable manner, and a drive mechanism (not shown), which is an object to be driven, of the robot is provided on the output side (upper side in the figures) of the planetary gear reduction mechanism 10 in a power-transmittable manner.

[0012] More specifically, the input shaft 31 of the planetary gear reduction mechanism 10 is rotated by an electric motor, and the output shaft 72 of the planetary gear reduction mechanism 10 drives the drive mechanism of the robot. The planetary gear reduction mechanism 10 reduces the rotation speed of the input shaft 31 to increase the torque, and outputs the increased torque from the output shaft 72.

[0013] As a result, the planetary gear reduction mechanism 10 can transmit a large drive torque to the drive mechanism of the robot even if the drive source is a small electric motor, which makes it possible to reduce the size of the electric motor and, in turn, to easily install it inside the arm of a robot or the like, which has a small installation space.

[0014] The planetary gear reduction mechanism 10 according to the present embodiment is not limited to use in driving the joints of a robot, but can also be applied to small-sized in-vehicle drive systems, such as power sliding door devices and power window devices mounted on vehicles such as automobiles.

[0015] [housing] The planetary gear reduction mechanism 10 includes a housing 20 that forms the outer shell of the planetary gear reduction mechanism 10. The housing 20 includes a housing body 21 formed in a substantially cylindrical shape, and a ring member 22 that is attached to one axial side (the lower side in the figure) of the housing body 21 and formed in an annular shape. Both the housing body 21 and the ring member 22 are made of aluminum, which reduces the overall weight of the planetary gear reduction mechanism 10.

[0016] The housing body 21 includes a cylindrical portion 21a extending in the axial direction of the planetary gear reduction mechanism 10, and a total of eight first flange portions 21b integrally provided on one axial side of the cylindrical portion 21a and protruding radially outward from the cylindrical portion 21a. Each of the eight first flange portions 21b is provided with an insertion hole 21c through which a fixing bolt (not shown) is inserted.

[0017] On the other hand, an annular second flange portion 21d is integrally provided on the other axial side (upper side in the figure) of the cylindrical portion 21a so as to protrude radially inward of the cylindrical portion 21a. An outer race of the first ball bearing BB1 is attached to the radially inner side of the second flange portion 21d. The one axial side (lower side in the figure) of the second flange portion 21d supports the other axial side (upper side in the figure) of the internal gear 40.

[0018] In this manner, the second flange portion 21d of the housing body 21 has the function of supporting both the first ball bearing BB1 and the internal gear 40.

[0019] Here, the first ball bearing BB1 rotatably supports the other axial side (upper side in the figure) of the carrier 60, and specifically, the inner race of the first ball bearing BB1 is mounted on the outer periphery of the output side cylindrical portion 66 (see Figure 7) that forms the carrier 60.

[0020] Further, a plurality of screw holes 21e are provided on the other axial side (upper side in the figure) of the second flange portion 21d. Fixing screws (not shown) for fixing the planetary gear reduction mechanism 10 to an internal fixing portion (not shown) of a robot arm or the like are screwed into these screw holes 21e.

[0021] The ring member 22 includes an annular main body 22a. A total of eight third flange portions 22b are integrally provided on the annular main body 22a so as to protrude radially outward. These third flange portions 22b are provided corresponding to the first flange portions 21b of the housing main body 21. Each of the third flange portions 22b is provided with a female threaded hole 22c into which a fixing bolt (not shown) is screwed.

[0022] In addition, in the axial direction of the housing 20, a total of eight fourth flange portions 42 provided on the internal gear 40 are sandwiched between the first flange portion 21b and the third flange portion 22b that form the housing 20. As a result, the reducer SD is accommodated and fixed inside the housing 20 by inserting a fixing bolt (not shown) into the insertion hole 21c of the first flange portion 21b and the insertion hole 42a of the fourth flange portion 42 and screwing it into the female threaded hole 22c of the third flange portion 22b.

[0023] In addition, an outer race of the second ball bearing BB2 is attached to the radially inner side of the ring member 22. That is, the ring member 22 has a function of supporting the second ball bearing BB2 and fixing the internal gear 40 inside the housing 20.

[0024] Here, the second ball bearing BB2 rotatably supports one axial side of the carrier 60 (the lower side in the figure), and specifically, the inner race of the second ball bearing BB2 is mounted on the outer periphery of the input side cylindrical portion 65 (see Figure 7) that forms the carrier 60.

[0025] Furthermore, a total of four positioning protrusions P (see FIG. 10) are integrally provided on the other axial side (upper side in the figure) of the ring member 22. These positioning protrusions P protrude toward the internal gear 40 in the axial direction of the ring member 22 and engage with engaging recesses (not shown) of the internal gear 40. This makes it easy to position the ring member 22 with respect to the internal gear 40 (improving assembly).

[0026] The first and second ball bearings BB1, BB2 supporting both axial ends of the carrier 60 are ball bearings of the same size and specifications. The first and second ball bearings BB1, BB2 are the largest ball bearings among all the ball bearings provided in the planetary gear reduction mechanism 10.

[0027] [Outline of the reducer] 3 to 7, the planetary gear reduction mechanism 10 has a plurality of gears. Specifically, the reduction gear SD accommodated inside the housing 20 includes one pinion gear 30, one internal gear 40, a total of three planetary gears 50, and a carrier 60 that holds these planetary gears 50. In other words, the reduction gear SD is a planetary reduction gear.

[0028] [Pinion gear] 3 and 4, the pinion gear 30 is provided integrally with the other axial side (upper side in the figures) of the input shaft 31. A rotating shaft (not shown) of an electric motor serving as a drive source is connected to one axial side (lower side in the figures) of the input shaft 31 in a power-transmitting manner. As a result, the pinion gear 30 rotates in a predetermined rotational direction at a predetermined rotational speed as the electric motor is driven to rotate.

[0029] The input shaft 31 corresponds to the input rotating body in the present invention, and the pinion gear 30 corresponds to the sun gear in the present invention.

[0030] Helical teeth 32 are integrally formed on the outer periphery of the pinion gear 30. The axial length of the pinion gear 30 (helical teeth 32) is slightly longer than the axial length of the planetary gear 50. This allows the helical teeth 32 to mesh reliably with the planetary gear 50.

[0031] The helical tooth 32 corresponds to one tooth in the present invention.

[0032] The helical teeth 32 are connected helically in the axial direction of the pinion gear 30, and the pinion gear 30 is provided with only one helical tooth 32. In other words, the pinion gear 30 has one tooth. The cross-sectional shape of the helical tooth 32 is substantially semicircular, and the helical tooth 32 fits into (meshews with) a meshing recess 51a of the planetary gear 50 (see FIG. 6).

[0033] In this way, by setting the number of teeth of the pinion gear 30 to "1", the gear transmission efficiency is improved and a large reduction ratio is obtained despite the small size. Therefore, it is possible to realize a reduction in size and power consumption of the electric motor that is the drive source.

[0034] [Internal gear] 3 and 5, the internal gear 40 is fixed to the radially inner side of the cylindrical portion 21a forming the housing main body 21. Specifically, the internal gear 40 is sandwiched between the housing main body 21 and the ring member 22 in the axial direction of the planetary gear reduction mechanism 10. The internal gear 40 includes a cylindrical main body 41 formed in a substantially cylindrical shape, and a total of eight fourth flange portions 42 protruding radially outward from the cylindrical main body 41 on one axial side of the cylindrical main body 41.

[0035] The cylindrical body 41 is disposed radially outward of the pinion gear 30, and a gear forming portion 43 is provided radially inward of the cylindrical body 41. A plurality of internal teeth 43a having a substantially semicircular cross section is integrally provided on the gear forming portion 43 of the cylindrical body 41, similar to the helical teeth 32 of the pinion gear 30. Here, the plurality of internal teeth 43a are inclined at a predetermined angle with respect to the axial direction of the cylindrical body 41, thereby enabling them to mesh with meshing recesses 51a (see FIG. 6) of the planetary gear 50.

[0036] The internal gear 40 corresponds to the internal gear in this invention.

[0037] Further, the fourth flange portion 42 provided on the internal gear 40 is provided corresponding to the first flange portion 21b of the housing body 21 and the third flange portion 22b of the ring member 22. Each of the eight fourth flange portions 42 is provided with an insertion hole 42a through which a fixing bolt (not shown) is inserted.

[0038] As a result, the fourth flange portion 42 is sandwiched between the first flange portion 21b and the third flange portion 22b, and thus the internal gear 40 is firmly fixed without any rattling in both the axial and circumferential directions of the housing 20.

[0039] [Planetary Gear] 3 and 6, a total of three planetary gears 50 are disposed between the pinion gear 30 and the internal gear 40 in the radial direction of the planetary gear reduction mechanism 10. The planetary gears 50 are disposed at equal intervals (120 degree intervals) in the circumferential direction of the pinion gear 30 and the internal gear 40, and are meshed with both the pinion gear 30 and the internal gear 40.

[0040] The planetary gear 50 corresponds to the planetary gear of the present invention.

[0041] The planetary gear 50 is formed in a generally cylindrical shape, and on its radially outer side is provided a gear forming portion 51. A plurality of meshing recesses 51a are provided in the gear forming portion 51 of the planetary gear 50 so as to be aligned in the circumferential direction. These meshing recesses 51a are inclined at a predetermined angle with respect to the axial direction of the planetary gear 50, so that the helical teeth 32 of the pinion gear 30 and the internal teeth 43a of the internal gear 40 can enter and mesh with the inside of the meshing recesses 51a.

[0042] Here, the planetary gear 50 has a meshing recess 51a inclined with respect to the axial direction of the planetary gear 50, and can also be called a helical gear.

[0043] Therefore, each planetary gear 50 rolls between the pinion gear 30 rotated by an electric motor (not shown) and the internal gear 40 fixed to the housing 20. The meshing recess 51a of the planetary gear 50 is recessed so that its cross-sectional shape is approximately semicircular.

[0044] A third ball bearing BB3 and a fourth ball bearing BB4 are provided on the radially inner side of the planetary gear 50. Specifically, the third ball bearing BB3 is provided on one axial side (lower side in the figure) of the planetary gear 50, and the fourth ball bearing BB4 is provided on the other axial side (upper side in the figure) of the planetary gear 50. Outer races of the third and fourth ball bearings BB3, BB4 are attached to the radially inner side of the planetary gear 50.

[0045] The third and fourth ball bearings BB3 and BB4 are ball bearings of the same size and specifications. The third and fourth ball bearings BB3 and BB4 are smaller than the first and second ball bearings BB1 and BB2 that rotatably support the carrier 60.

[0046] Each of the three planetary gears 50 is rotatably supported by a support shaft 52. Specifically, when assembling the carrier assembly CA (see FIG. 9), the support shaft 52 is inserted into inner races of the third and fourth ball bearings BB3 and BB mounted on the planetary gears 50. Both axial ends of the support shaft 52 are fixed in first and second support shaft fixing holes 64a and 64b provided in the carrier 60, respectively.

[0047] A first washer WS1 is provided on one axial side (lower side in the figure) of the third ball bearing BB3 and the other axial side (upper side in the figure) of the fourth ball bearing BB4. This allows planetary gear 50, on which the third and fourth ball bearings BB3 and BB4 are mounted, to rotate smoothly without rattling relative to carrier 60 and support shaft 52.

[0048] [Career] 3 and 7, the carrier 60 is formed into a generally cylindrical shape by cutting an aluminum material or the like. The carrier 60 has a cylindrical main body 61, and the cylindrical main body 61 is provided with a total of three gear support parts 62. Each gear support part 62 has a function of supporting the planetary gear 50 rotatably.

[0049] Here, the carrier 60 rotatably supports a total of three planetary gears 50, and corresponds to the planetary carrier of the present invention.

[0050] The gear support portions 62 are provided at equal intervals (at 120 degree intervals) in the circumferential direction of the cylindrical main body portion 61, and include communication holes 62a that communicate between the radially inner side and the radially outer side of the cylindrical main body portion 61. The communication hole 62a is formed in a substantially square shape when the carrier 60 is viewed from the side. The planetary gear 50 is rotatably housed in the communication hole 62a via a small gap.

[0051] Furthermore, in order to allow the planetary gear 50 to rotate smoothly without rattling, the carrier 60 is one of the components that require particularly high machining precision among the components that form the planetary gear reduction mechanism 10.

[0052] Also, first and second pedestals 63a, 63b supporting both axial sides of the planetary gear 50 are provided on both sides of the communication hole 62a in the axial direction of the carrier 60. Specifically, the first pedestal 63a is disposed on one axial side (lower side in the figure) of the carrier 60, and the second pedestal 63b is disposed on the other axial side (upper side in the figure) of the carrier 60. First washers WS1 provided on both axial sides of the planetary gear 50 are in contact with the first and second pedestals 63a, 63b, respectively.

[0053] An input side cylindrical portion 65 having a smaller diameter than the cylindrical main body portion 61 is provided on one axial side of the carrier 60. An insertion hole 65a through which the input shaft 31 (pinion gear 30) is inserted is provided on the radially inner side of the input side cylindrical portion 65, and a fifth ball bearing BB5 that rotatably supports the input shaft 31 is attached to the insertion hole 65a. Specifically, an outer ring (outer race) of the fifth ball bearing BB5 is attached to the insertion hole 65a.

[0054] The inner race of the fifth ball bearing BB5 is fixed by press fitting to approximately the center of the input shaft 31 in the axial direction (near the pinion gear 30). One axial side of the input side cylindrical portion 65 is covered with a cover member 67 formed in a substantially disk shape. The cover member 67 has a function of preventing the fifth ball bearing BB5 from falling off the input side cylindrical portion 65. In other words, the cover member 67 has a function of preventing the input shaft 31, to which the fifth ball bearing BB5 is fixed, from falling off the carrier 60.

[0055] A total of three screw insertion holes 67a (see FIG. 11) are provided in the cover member 67, and a total of three screw holes 65b are provided on one axial side of the input side cylindrical portion 65. Fixing screws (not shown) for fixing the cover member 67 to the input side cylindrical portion 65 are screwed into the total of three screw holes 65b.

[0056] In addition, an inner ring of a second ball bearing BB2 is mounted on the radial outside of the input side cylindrical portion 65, and the inner ring of the second ball bearing BB2 is abutted from one axial side against a first step portion ST1 (see Figure 7) between the cylindrical main body portion 61 and the input side cylindrical portion 65.

[0057] Furthermore, a first support shaft fixing hole 64a is provided at a location where the first seat 63a of the input side cylindrical portion 65 is provided so as to extend in the axial direction of the carrier 60. Three first support shaft fixing holes 64a are provided corresponding to the first seats 63a and are arranged at equal intervals (120 degree intervals) in the circumferential direction of the cylindrical main body portion 61. The first support shaft fixing hole 64a penetrates both the first seat 63a and the input side cylindrical portion 65, and one axial side (lower side in the figure) of the support shaft 52 that rotatably supports the planetary gear 50 is attached to the first support shaft fixing hole 64a.

[0058] An output side cylindrical portion 66 having the same diameter as the input side cylindrical portion 65 is provided on the other axial side of the carrier 60. A through hole 66a is provided on the radially inner side of the output side cylindrical portion 66, and a sixth ball bearing BB6 that rotatably supports the other axial side of the input shaft 31 is mounted in the through hole 66a, and a play adjustment member 68 that adjusts the play of the input shaft 31 relative to the carrier 60 in the axial direction is also provided.

[0059] Specifically, an outer ring (outer race) of the sixth ball bearing BB6 is mounted in the through hole 66a. An inner race (inner race) of the sixth ball bearing BB6 is mounted to a bearing mounting portion 31a of the input shaft 31. The bearing mounting portion 31a is cylindrical and has a smaller diameter than the main body of the input shaft 31, and a support step 31b (see FIG. 4) is provided between the bearing mounting portion 31a and the pinion gear 30. The inner ring of the sixth ball bearing BB6 is abutted against the support step 31b from the other axial side via a second washer WS2 (see FIG. 11).

[0060] The second washer WS2 has the function of eliminating rattle between the sixth ball bearing BB6 and the input shaft 31, allowing the input shaft 31 to rotate smoothly.

[0061] Here, an angular ball bearing is used for the sixth ball bearing BB6. As a result, the sixth ball bearing BB6 presses the input shaft 31 to one axial side (the lower side in the figure) while receiving axial force from the backlash adjustment member 68. This prevents the input shaft 31 from wobbling between the fifth ball bearing BB5 and the sixth ball bearing BB6, improving quietness during operation of the planetary gear reduction mechanism 10.

[0062] The play adjustment member 68 is screwed into the through hole 66a, and is moved to one axial side (downward in the figure) by rotating the play adjustment member 68 clockwise. The play adjustment member 68 presses the outer ring of the sixth ball bearing BB6 toward one axial side. On the other hand, the play adjustment member 68 is moved to the other axial side (upward in the figure) by rotating the play adjustment member 68 counterclockwise.

[0063] Moreover, an inner ring of a first ball bearing BB1 is attached to the radial outside of the output side cylindrical portion 66, and the inner ring of the first ball bearing BB1 abuts from the other axial side against a second step portion ST2 (see FIG. 7) between the cylindrical main body portion 61 and the output side cylindrical portion 66. Specifically, a third washer WS3 (see FIG. 10) is provided between the inner ring of the first ball bearing BB1 and the second step portion ST2, and the inner ring of the first ball bearing BB1 abuts against the second step portion ST2 via the third washer WS3.

[0064] Furthermore, at the location of the second seat 63b of the output side cylindrical portion 66, a second support shaft fixing hole 64b is provided so as to extend in the axial direction of the carrier 60. Three second support shaft fixing holes 64b are provided corresponding to the second seat 63b, and are arranged at equal intervals (120 degree intervals) in the circumferential direction of the cylindrical main body portion 61. The second support shaft fixing holes 64b penetrate both the second seat 63b and the output side cylindrical portion 66, and the other axial side (upper side in the figure) of the support shaft 52 that rotatably supports the planetary gear 50 is attached to the second support shaft fixing holes 64b.

[0065] Here, the support shaft 52 is inserted into the first support shaft fixing hole 64a without any rattling, and is fixed into the second support shaft fixing hole 64b by press fitting. This reduces the insertion load of the support shaft 52 into the first and second support shaft fixing holes 64a, 64b when assembling the carrier assembly CA (see FIG. 9), improving ease of assembly.

[0066] The first and second support shaft fixing holes 64a, 64b to which both axial ends of the support shaft 52 are fixed correspond to the support shaft fixing holes of the present invention.

[0067] In this way, the total of three second support shaft fixing holes 64b and the total of three first support shaft fixing holes 64a are respectively arranged coaxially in the axial direction of the carrier 60. Here, the carrier 60 is formed with high precision, that is, formed without dimensional error, by cutting an aluminum material. Therefore, as shown in Fig. 7, the rotation center C1 of the carrier 60 and the central axis C2 (rotation center of the planetary gear 50) of the first and second support shaft fixing holes 64a, 64b arranged around the rotation center C1 are arranged at the specified positions of the carrier 60 with high precision.

[0068] Furthermore, a plurality of female threaded portions 66b are provided on the other axial side (upper side in the figure) of the output side cylindrical portion 66. These female threaded portions 66b extend in the axial direction of the carrier 60. Fixing screws (not shown) for fixing the shaft coupling 70 (see Figures 1 to 3) are screwed into the female threaded portions 66b. Note that in order to ensure sufficient fixing strength, it is preferable to use at least three fixing screws for fixing the shaft coupling 70 to the carrier 60.

[0069] [Shaft coupling] 1 to 3, the planetary gear reduction mechanism 10 includes a shaft coupling 70 that is connected to a drive mechanism (not shown) of a robot, which is an object to be driven, so as to be capable of transmitting power. Like the carrier 60, the shaft coupling 70 is also formed with high precision, that is, formed without dimensional error, by cutting an aluminum material or the like.

[0070] The shaft coupling 70 includes a fixed main body 71 formed in a substantially disk shape, and an output shaft 72 provided integrally with the fixed main body 71. The fixed main body 71 is fixed to the output side cylindrical portion 66 of the carrier 60. The output shaft 72 extends from the other axial side (upper side in the figure) of the fixed main body 71 toward the drive mechanism (not shown) of the robot, and is substantially cylindrical.

[0071] The shaft coupling 70 is fixed to the carrier 60 and drives a drive mechanism (not shown) of the robot, and corresponds to the output rotating body in the present invention.

[0072] 1 and 3, a total of three fixing holes 71a are provided in the fixed main body portion 71. These fixing holes 71a are arranged at equal intervals (120 degree intervals) in the circumferential direction of the fixed main body portion 71, centered on the output shaft 72. The total of three fixing holes 71a are provided in correspondence with the total of three second support shaft fixing holes 64b (see FIG. 7) provided in the output side cylindrical portion 66 of the carrier 60.

[0073] Steel fixing pins 73 are fixed by press fitting into each of the three fixing holes 71a. These fixing pins 73 are inserted into the respective fixing holes 71a from the other axial side (upper side in the figure) of the shaft coupling 70, and one axial side (lower side in the figure) of the fixing pins 73 is fixed by press fitting into the second support shaft fixing holes 64b of the carrier 60. In other words, the fixing pins 73 fixed to the fixed main body portion 71 are respectively fixed to the second support shaft fixing holes 64b, and the shaft coupling 70 is fixed to the carrier 60 by the fixing pins 73.

[0074] In this way, the fixing pin 73 is press-fitted into both the fixing hole 71a and the second support shaft fixing hole 64b, and the fixing hole 71a corresponds to the fixing member fixing hole in the present invention. In other words, the fixing pin 73 has a function of fixing the shaft coupling 70 and the carrier 60, which are each formed (manufactured) with high precision, to each other. The fixing pin 73 corresponds to the fixing member in the present invention.

[0075] The fixing pin 73 is press-fitted into both the fixing hole 71a and the second support shaft fixing hole 64b, whereby the shaft coupling 70 can be positioned with high precision relative to the carrier 60 and the shaft coupling 70 and the second support shaft fixing hole 64b can be securely fixed to each other.

[0076] One axial side of the fixing pin 73 is provided with a tapered portion 73a formed in a tapered shape so that the fixing pin 73 can be easily inserted into the fixing hole 71a and the second support shaft fixing hole 64b (improving assembly).

[0077] The fixed main body portion 71 is provided with a plurality of screw insertion holes 71b through which fixing screws (not shown) for fixing the shaft coupling 70 to the carrier 60 are inserted. These screw insertion holes 71b are provided in correspondence with a plurality of female thread portions 66b (see FIG. 7) provided in the output side cylindrical portion 66.

[0078] [Assembly Instructions] Next, a procedure for assembling the planetary gear reduction mechanism 10 formed as above will be described in detail with reference to FIGS.

[0079] Figure 8 is an oblique view showing the assembly procedure for the carrier assy, ​​Figure 9 is an oblique view showing the assembly procedure for the internal gear to the carrier assy, ​​Figure 10 is an oblique view showing the assembly procedure for the housing body and ring member, Figure 11 is an oblique view showing the assembly procedure for the pinion gear and backlash adjustment member, and Figure 12 is an oblique view showing the assembly procedure for the shaft coupling to the carrier.

[0080] [Assembling the carrier assembly] As shown in Fig. 8, first, the carrier assembly CA is assembled. Specifically, a carrier 60 manufactured through a separate manufacturing process, a total of three planetary gears 50, and a total of three support shafts 52 are prepared. Note that, for ease of viewing, Fig. 8 shows one each of the planetary gears 50 and the support shafts 52.

[0081] Next, as shown by arrow M1 in Fig. 8, the planetary gear 50 is brought into contact with the communication hole 62a from the radially outer side of the carrier 60. At this time, the third and fourth ball bearings BB3 and BB4 (see Fig. 3) are mounted in advance on the radially inner side of the planetary gear 50. Also, first washers WS1 are mounted on the third and fourth ball bearings BB3 and BB4, respectively (see Fig. 3).

[0082] Thereafter, the planetary gear 50 is inserted into the communication hole 62a, and the support shaft 52 is brought to face the other axial side of the carrier 60, as shown by the arrow M2 in Fig. 8. At this time, the input side cylindrical portion 65 of the carrier 60 is disposed on one axial side (lower side in the figure), and the output side cylindrical portion 66 of the carrier 60 is disposed on the other axial side (upper side in the figure).

[0083] Then, the support shaft 52 is inserted into the second support shaft fixing hole 64b and the first support shaft fixing hole 64a in this order. Note that the support shaft 52 is inserted into the first support shaft fixing hole 64a, and the support shaft 52 is press-fit into the second support shaft fixing hole 64b. Therefore, the insertion load of the support shaft 52 is not so large, and the carrier assembly CA can be easily assembled.

[0084] Thereafter, the above-described attachment operation of the planetary gear 50 to the communication hole 62a is carried out twice in succession, thereby completing the assembly operation of the carrier assembly CA (see FIG. 9).

[0085] [Installing the internal gear to the carrier assembly] Next, as shown in FIG. 9, an internal gear 40 manufactured through a separate manufacturing process is prepared, and the internal gear 40 is attached to the assembled carrier assembly CA.

[0086] Specifically, the internal gear 40 is brought to face the other axial side of the carrier assembly CA, i.e., the output side cylindrical portion 66 side (upper side in the figure), as indicated by the arrow M3 in the figure. At this time, the fourth flange portion 42 side in the axial direction of the internal gear 40 faces the carrier assembly CA.

[0087] The internal gear 40 is then disposed so as to cover the radially outer side of the carrier assembly CA. At this time, the planetary gear 50 of the carrier assembly CA is capable of smoothly rotating relative to the carrier 60, so that the internal teeth 43a of the internal gear 40 and the meshing recesses 51a of the planetary gear 50 mesh smoothly with each other.

[0088] This completes the assembly work of the internal gear 40 to the carrier assembly CA.

[0089] [Assembly of housing body and ring components] 10, the housing body 21, the ring member 22, and the third washer WS3, which are manufactured through a separate manufacturing process, are prepared. Note that the first ball bearing BB1 is attached to the housing body 21 in advance, and the second ball bearing BB2 is attached to the ring member 22 in advance.

[0090] Thereafter, as shown by arrow M4 in the figure, a third washer WS3 is attached to the output side cylindrical portion 66 of the carrier 60. Next, as shown by arrow M5 in the figure, the housing body 21 is attached so as to cover the radial outside of the internal gear 40. At this time, the first flange portion 21b side of the housing body 21 in the axial direction faces the internal gear 40.

[0091] Thereafter, as indicated by arrow M6 in the figure, the ring member 22 (the second ball bearing BB2) is attached to the input side cylindrical portion 65 of the carrier 60. At this time, the side of the ring member 22 on which the positioning protrusion P is provided faces the internal gear 40. Then, while the second ball bearing BB2 is being attached to the input side cylindrical portion 65, the positioning protrusion P of the ring member 22 is engaged with an engagement recess (not shown) of the internal gear 40.

[0092] Then, a fixing bolt (not shown) is inserted through the insertion hole 21c of the first flange portion 21b and the insertion hole 42a of the fourth flange portion 42, and the fixing bolt is screwed into the female threaded hole 22c of the third flange portion 22b. This causes the reducer SD to be accommodated inside the housing 20, and the assembly of the housing main body 21 and the ring member 22 is completed.

[0093] [Assembly of pinion gear and backlash adjustment parts] 11, an input shaft 31 having a pinion gear 30 manufactured through a separate manufacturing process, and a cover member 67 are prepared. A fifth ball bearing BB5 is fixed to the input shaft 31 in advance. A second washer WS2, a sixth ball bearing BB6, and a backlash adjustment member 68 are also prepared.

[0094] Thereafter, as indicated by an arrow M7 in the figure, the pinion gear 30 is brought into contact with the input side cylindrical portion 65 (see FIG. 3) of the carrier 60. Then, the pinion gear 30 is inserted between a total of three planetary gears 50 (see FIG. 6). At this time, the planetary gears 50 are able to rotate smoothly relative to the carrier 60. Therefore, while each planetary gear 50 rotates, the helical teeth 32 of the pinion gear 30 and the meshing recesses 51a (see FIG. 6) of the planetary gears 50 mesh smoothly with each other.

[0095] Then, the fifth ball bearing BB5 is attached to the insertion hole 65a (see FIG. 3) of the input side cylindrical portion 65. Furthermore, as shown by the arrow M8 in FIG. 11, the cover member 67 is fixed to the input side cylindrical portion 65 (see FIG. 3). At this time, a total of three fixing screws (not shown) are inserted into the screw insertion holes 67a of the cover member 67 and screwed into the threaded holes 65b (see FIG. 3) of the input side cylindrical portion 65. This prevents the input shaft 31 (pinion gear 30) from coming off the carrier 60.

[0096] Next, as shown by the arrow M9 in the figure, the second washer WS2 is inserted into the through hole 66a of the output side cylindrical portion 66 and placed on the support step 31b of the input shaft 31. Thereafter, the sixth ball bearing BB6 is inserted into the through hole 66a of the output side cylindrical portion 66 and attached to the bearing attachment portion 31a of the input shaft 31. Then, the backlash adjustment member 68 is screwed into the through hole 66a.

[0097] Then, as shown by the arrow M10 in the figure, the play adjustment member 68 is rotated clockwise to press the outer ring of the sixth ball bearing BB6 toward one axial side by the play adjustment member 68. This prevents the input shaft 31 from wobbling in the axial direction, and the assembly work of the pinion gear 30 and the play adjustment member 68 is completed.

[0098] [Assembling the shaft coupling to the carrier] Next, as shown in FIG. 12, a shaft coupling 70 and a total of three fixing pins 73 manufactured through a separate manufacturing process are prepared.

[0099] Thereafter, as shown by the arrow M11 in the figure, the fixed main body portion 71 of the shaft coupling 70 is brought into contact with the output side cylindrical portion 66 of the carrier 60. At this time, the total of three fixing holes 71a provided in the fixed main body portion 71 and the total of three second support shaft fixing holes 64b provided in the output side cylindrical portion 66 are brought into a state in which they face each other in the axial direction (are arranged coaxially).

[0100] Next, as shown by the arrow M12 in the figure, a total of three fixing pins 73 are press-fitted in this order into both the fixing holes 71a and the second support shaft fixing holes 64b. At this time, the side of the fixing pins 73 on which the tapered portions 73a are provided faces the fixed main body portion 71.

[0101] As a result, the shaft coupling 70 is accurately positioned relative to the carrier 60 and is firmly fixed. Next, the shaft coupling 70 is fixed to the carrier 60 using a plurality of fixing screws (not shown). At this time, any one of the screw insertion holes 71b of the fixed main body portion 71 and any one of the female threaded portions 66b of the output side cylindrical portion 66 are used. Note that it is preferable to use three fixing screws to fix the shaft coupling 70 to the carrier 60 from the viewpoint of fixing strength.

[0102] As a result, the shaft coupling 70 will not come off the carrier 60 due to vibrations or the like when the planetary gear reduction mechanism 10 is driven, and finally, the assembly work of the planetary gear reduction mechanism 10 is completed.

[0103] As described above in detail, according to the planetary gear reduction mechanism 10 of embodiment 1, the carrier 60 is provided with first and second support shaft fixing holes 64a, 64b to which the support shaft 52 that rotatably supports the planetary gear 50 is fixed, and the shaft coupling 70 is fixed to the carrier 60 by a fixing pin 73 fixed to the second support shaft fixing hole 64b.

[0104] This makes it possible to fix the shaft coupling 70 with high precision to the carrier 60 that is formed with high machining precision. Therefore, it is possible to realize the planetary gear reduction mechanism 10 that is capable of driving an object to be driven, such as a drive mechanism of a robot, with high precision.

[0105] Furthermore, according to the planetary gear reduction mechanism 10 of embodiment 1, three planetary gears 50 are provided at equal intervals (120 degree intervals) around the circumferential direction of the pinion gear 30, and the shaft coupling 70 is fixed to the carrier 60 by three fixing pins 73.

[0106] This allows the pinion gear 30 to be held in good balance by the three planetary gears 50. This reduces the operating noise of the planetary gear reduction mechanism 10 and enables efficient transmission of power from the pinion gear 30 to the three planetary gears 50. In addition, it allows the shaft coupling 70 to be fixed to the carrier 60 at three points by the three fixing pins 73 in a well-balanced manner.

[0107] Furthermore, according to the planetary gear reduction mechanism 10 of the first embodiment, the fixing pin 73 is press-fitted into both the fixing hole 71 a provided in the shaft coupling 70 and the second support shaft fixing hole 64 b provided in the carrier 60 .

[0108] This allows the shaft coupling 70 to be securely fixed to the carrier 60 without any rattling.

[0109] Furthermore, according to the planetary gear reduction mechanism 10 of the first embodiment, the pinion gear 30 has only one helical tooth 32 that is connected in a spiral shape in the axial direction of the input shaft 31 .

[0110] This makes it possible to improve the transmission efficiency of the gears and obtain a large reduction ratio despite the small size, thereby enabling the electric motor serving as the drive source to be made smaller and to consume less power.

[0111] Furthermore, according to the planetary gear reduction mechanism 10 of the first embodiment, the second support shaft fixing hole 64b provided in the carrier 60 is used to support the fixing pin 73 in addition to supporting the support shaft 52. In other words, there is no need to provide a new support structure for supporting the fixing pin 73, which can reduce the energy required to manufacture the planetary gear reduction mechanism 10. Therefore, it is possible to achieve the Sustainable Development Goals (SDGs) established by the United Nations, particularly Goal 7 (Ensure access to affordable, reliable, sustainable and modern energy for all) and Goal 13 (Take urgent action to combat climate change and its impacts).

[0112] [Embodiment 2] Next, a second embodiment of the present invention will be described in detail with reference to the drawings. Note that parts having the same functions as those in the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0113] FIG. 13 is a cross-sectional view corresponding to FIG. 3 and showing a planetary gear reduction mechanism according to the second embodiment.

[0114] As shown in FIG. 13, the planetary gear reduction mechanism 100 of the second embodiment differs from the planetary gear reduction mechanism 10 of the first embodiment (see FIG. 3) only in the shape of the shaft coupling (output side rotating body) 110.

[0115] The shaft coupling 110 includes a fixed main body 71 formed in a substantially disk shape, and an output shaft 111 formed in a substantially cylindrical shape and integral with the fixed main body 71. That is, as shown in Fig. 3, in the first embodiment, the fixed main body 71 is provided with a substantially columnar output shaft 72, but as shown in Fig. 13, in the second embodiment, the fixed main body 71 is provided with a substantially cylindrical output shaft 111.

[0116] The second embodiment configured as above can also achieve the same effects as the first embodiment.

[0117] As in the above-mentioned embodiment 1 (planetary gear reduction mechanism 10) and embodiment 2 (planetary gear reduction mechanism 100), the shape of the output shaft 72, 111 provided in the shaft coupling 70, 110 can be arbitrarily set to correspond to the shape of the robot's driving mechanism or other driving mechanisms, i.e., the object to be driven.

[0118] The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiments, all of the six bearings are the first to sixth ball bearings BB1 to BB6, but the present invention is not limited to this, and some of the bearings can be replaced with bearings also called bushes or metals.

[0119] In addition, in each of the above-mentioned embodiments, a total of three planetary gears 50 are provided, but the present invention is not limited to this, and four or more planetary gears 50 may be provided. If there are two planetary gears 50 (an even number), they will be arranged 180 degrees apart, making it difficult to maintain the pinion gears 30 in a well-balanced state. This leads to increased operating noise and reduced power transmission efficiency. On the other hand, if there are five or more planetary gears 50, assembly will be difficult and the device will become larger. Therefore, when used for applications such as those in the above-mentioned embodiments, it is preferable that the number of planetary gears 50 is three (an odd number).

[0120] Furthermore, the above-mentioned procedure for assembling the planetary gear reduction mechanism 10 is merely one example among many possible procedures, and it goes without saying that other procedures can also be used for assembly. For example, "assembly of the pinion gear 30 and the backlash adjustment member 68" shown in Fig. 11 can be performed prior to "assembly of the housing body 21 and the ring member 22" shown in Fig. 10.

[0121] In addition, the material, shape, size, number, installation location, etc. of each component in each of the above-mentioned embodiments are arbitrary as long as the present invention can be achieved, and are not limited to the above-mentioned embodiments. [Explanation of symbols]

[0122] 10: planetary gear reduction mechanism, 20: housing, 21: housing body, 21a: cylindrical portion, 21b: first flange portion, 21c: insertion hole, 21d: second flange portion, 21e: screw hole, 22: ring member, 22a: annular body, 22b: third flange portion, 22c: female screw hole, 30: pinion gear (sun gear), 31: input shaft (input side rotating body), 31a: bearing mounting portion, 31b: support step, 32: helical tooth (one tooth), 40: Internal gear (internal gear), 41: cylindrical main body, 42: fourth flange portion, 42a: insertion hole, 43: gear forming portion, 43a: internal teeth, 50: planetary gear (planetary gear), 51: gear forming portion, 51a: meshing recess, 52: support shaft, 60: carrier (planetary carrier), 61: cylindrical main body portion, 62: gear support portion, 62a: communication hole, 63a: first base, 63b: second base, 64a: first support shaft fixing hole (support shaft fixing hole), 64b: second support shaft Fixing hole (support shaft fixing hole), 65: input side cylindrical part, 65a: insertion hole, 65b: screw hole, 66: output side cylindrical part, 66a: through hole, 66b: female threaded part, 67: cover member, 67a: screw insertion hole, 68: backlash adjustment member, 70: shaft coupling (output side rotating body), 71: fixed main body part, 71a: fixing hole (fixing member fixing hole), 71b: screw insertion hole, 72: output shaft, 73: fixing pin (fixing member), 73a: tapered part, 100: planetary gear reduction mechanism, 110 : Shaft coupling (output side rotating body), 111: Output shaft, BB1: First ball bearing, BB2: Second ball bearing, BB3: Third ball bearing, BB4: Fourth ball bearing, BB5: Fifth ball bearing, BB6: Sixth ball bearing, CA: Carrier assembly, P: Positioning protrusion, SD: Reducer, ST1: First step, ST2: Second step, WS1: First washer, WS2: Second washer, WS3: Third washer

Claims

1. A planetary gear reduction mechanism having a plurality of gears, an input side rotating body connected to a drive source so as to be capable of transmitting power; A sun gear provided on the input side rotor; an internal gear disposed radially outside the sun gear; a planetary gear disposed between the sun gear and the internal gear; a planetary carrier that rotatably supports the planetary gear; An output side rotor fixed to the planetary carrier and configured to drive a driven object; Equipped with The planetary carrier is provided with a support shaft fixing hole to which a support shaft that rotatably supports the planetary gear is fixed, The output side rotating body is fixed to the planetary carrier by a fixing member fixed to the support shaft fixing hole. Planetary gear reduction mechanism.

2. At least three of the planetary gears are provided at equal intervals in the circumferential direction of the sun gear, The output side rotating body is fixed to the planetary carrier by at least three of the fixing members.

2. The planetary gear reduction mechanism according to claim 1.

3. 2. The planetary gear reduction mechanism according to claim 1, The fixing member is The fixed member is press-fitted into both a fixed member fixing hole provided in the output side rotating body and the support shaft fixing hole provided in the planetary carrier. Planetary gear reduction mechanism.

4. The sun gear has only one tooth spirally connected in the axial direction of the input rotor. The planetary gear reduction mechanism according to any one of claims 1 to 3.

Images