Planetary gear speed reducing mechanism

Abstract

The invention provides a planetary gear speed reduction mechanism capable of performing stable operation. A fifth ball bearing (BB5) that rotatably supports the rotating shaft is provided on one side of the pinion gear (30) in the axial direction of the rotating shaft (31), and a sixth ball bearing (BB6) that rotatably supports the rotating shaft is provided on the other side of the pinion gear in the axial direction of the rotating shaft. The bracket (60) is provided with a bearing fixing part (65c) which supports the fifth ball bearing in a manner that the fifth ball bearing cannot move along the axial direction of the rotating shaft, and a bearing guide part (66c) which supports the sixth ball bearing in a manner that the sixth ball bearing can move along the axial direction of the rotating shaft. The fifth ball bearing and the sixth ball bearing cannot approach each other with respect to the axial direction of the rotating shaft, and the female thread portion (66d) is provided with a shake adjustment member (68) that presses the sixth ball bearing toward the side where the fifth ball bearing is provided.

Description

Technical Field

[0001] The invention relates to a planetary gear reduction mechanism comprising a plurality of gears. Background Art

[0002] For example, Patent Document 1 describes a planetary reduction gear, which is formed by axially overlapping the front-stage and rear-stage planetary reduction mechanisms including a sun gear, planetary gears, a planetary carrier, and an internal gear. As a result, the rotation speed of the sun gear of the front-stage planetary reduction gear is reduced, and a high-torque rotational force is output from the planetary carrier of the rear-stage planetary reduction gear.

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] [Patent Document 1] International Publication No. 2021 / 014647 Summary of the invention

[0006] [Problems to be solved by the invention]

[0007] In the technology described in Patent Document 1, a pressurizing mechanism is provided on the planetary carrier of the rear stage, and the pressurizing mechanism is arranged in a manner of supporting between the planetary carrier of the rear stage and the planetary carrier of the front stage in which the sun gear of the rear stage is integrally provided. As a result, the sun gear of the rear stage meshes with the planetary gear of the rear stage in a state where the movement in the axial direction is restricted. However, for the sun gear of the front stage, there is no additional pressurization of the pressurizing mechanism, and there is a problem that the sun gear of the front stage shakes in the axial direction or causes rotational vibration, and the operation becomes unstable.

[0008] An object of the present invention is to provide a planetary gear reduction mechanism capable of stable operation.

[0009] [Technical means to solve the problem]

[0010] In one embodiment of the present invention, a planetary gear reduction mechanism includes: a sun gear, which is arranged on a rotating shaft; an internal gear, which is arranged on the radial outside of the sun gear; a planetary gear, which is arranged between the sun gear and the internal gear; and a planetary carrier, which supports the planetary gear so that it can rotate freely. The planetary gear reduction mechanism has: a first bearing, which is arranged on one side of the sun gear in the axial direction of the rotating shaft, and supports the rotating shaft so that it can rotate freely; a second bearing, which is arranged on the other side of the sun gear in the axial direction of the rotating shaft, and supports the rotating shaft so that it can rotate freely; a first bearing support portion, which is arranged on the planetary carrier, and supports the first bearing in a manner that it cannot move in the axial direction of the rotating shaft; and a second bearing support portion, which is arranged on the planetary carrier, and supports the second bearing in a manner that it can move in the axial direction of the rotating shaft, the first bearing and the second bearing are arranged in a manner that they cannot approach each other with respect to the axial direction of the rotating shaft, and a pressing member is provided on the second bearing support portion to press the second bearing toward the side where the first bearing is provided.

[0011] [Effects of the Invention]

[0012] The present invention can realize a planetary gear reduction mechanism capable of performing stable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a perspective view of the planetary gear reduction mechanism viewed from the output side.

[0014] Figure 2 This is a perspective view of the planetary gear reduction mechanism viewed from the input side.

[0015] Figure 3 Yes means Figure 1 A cross-sectional view of the internal structure of a planetary gear reduction mechanism.

[0016] Figure 4 This is an enlarged cross-sectional view of the shake adjustment mechanism.

[0017] Figure 5 It is an enlarged cross-sectional view of part of the fifth ball bearing.

[0018] Figure 6 This is a three-dimensional diagram showing the pinion gear as a single unit.

[0019] Figure 7 This is a three-dimensional diagram showing an internal gear as a single body.

[0020] Figure 8 It is a three-dimensional diagram showing three helical gears.

[0021] Fig. 9This is a three-dimensional diagram showing the bracket as a single body.

[0022] Fig.10 It is an exploded perspective view of the sway adjustment mechanism.

[0023] Fig.11 It is a three-dimensional diagram showing the assembly process of the bracket assembly.

[0024] Fig.12 This is a perspective view showing the assembly process of the internal gear relative to the carrier assembly.

[0025] Fig.13 It is a perspective view showing the assembly process of the housing body and the ring member.

[0026] Fig.14 This is a perspective view showing the assembly process of the pinion gear and the play adjustment mechanism.

[0027] Fig.15 This is a graph comparing the transmission efficiency [%) of gears.

[0028] [Explanation of Symbols]

[0029] 10: Planetary gear reduction mechanism

[0030] 20: Shell

[0031] 21: Shell body

[0032] 21a: Cylindrical part

[0033] 21b: First flange portion

[0034] 21c: Through hole

[0035] 21d: Second flange portion

[0036] 21e: threaded hole

[0037] 22: Ring component

[0038] 22a: Ring body

[0039] 22b: Third flange portion

[0040] 22c: Internal thread hole

[0041] 30: Pinion (sun gear)

[0042] 31: Rotation axis

[0043] 31a: Bearing installation part

[0044] 31b: Supporting step (step part)

[0045] 32: Helical teeth (one tooth)

[0046] 40: Internal gear (internal gear)

[0047] 41: Tubular body

[0048] 42: Fourth flange portion

[0049] 42a: Through hole

[0050] 43: Gear forming part

[0051] 43a: Internal teeth

[0052] 50: Planetary gear (planetary gear)

[0053] 51: Gear forming part

[0054] 51a: Engagement recess

[0055] 52: Support shaft

[0056] 60: Bracket (planet carrier)

[0057] 61: Tubular main body

[0058] 62: Gear support

[0059] 62a: Communication hole

[0060] 63a: First base

[0061] 63b: Second base

[0062] 64a: First support shaft fixing hole

[0063] 64b: Second support shaft fixing hole

[0064] 65: Input side cylinder

[0065] 65a: Through hole

[0066] 65b: threaded hole

[0067] 65c: bearing fixing portion (first bearing supporting portion)

[0068] 66: Output side cylinder

[0069] 66a: Bearing support

[0070] 66b: Internal threaded hole

[0071] 66c: bearing guide portion (second bearing support portion)

[0072] 66d: Internal thread portion (second bearing support portion)

[0073] 67: Cover member

[0074] 67a: Screw insertion hole

[0075] 68: Shake adjustment member (pressing member)

[0076] 68a: Adjust the main body

[0077] 68b: Pressing part

[0078] BA: Shake adjustment mechanism

[0079] BB1: First ball bearing

[0080] BB2: Second ball bearing

[0081] BB3: Third ball bearing (ball bearing)

[0082] BB4: Fourth ball bearing (ball bearing)

[0083] BB5: Fifth ball bearing (first bearing)

[0084] BB6: Sixth ball bearing (second bearing)

[0085] CA: Bracket assembly

[0086] IR5: Inner ring (first inner ring)

[0087] IR6: Inner ring (second inner ring)

[0088] OR5: Outer ring (first outer ring)

[0089] OR6: Outer ring (second outer ring)

[0090] P: Positioning convex part

[0091] SD: Reducer

[0092] ST1: First step

[0093] ST2: Second step

[0094] WS1: First Washer

[0095] WS2: Second washer

[0096] WS3: Third washer DETAILED DESCRIPTION

[0097] Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

[0098] Figure 1 1 shows a perspective view of the planetary gear reduction mechanism viewed from the output side. Figure 2 The following is a perspective view of the planetary gear reduction mechanism viewed from the input side. Figure 3 Shows the representation Figure 1 A cross-sectional view of the internal structure of the planetary gear reduction mechanism. Figure 4 An enlarged cross-sectional view showing a portion of the shake adjustment mechanism, Figure 5 An enlarged sectional view showing a portion of the fifth ball bearing, Figure 6 A perspective view showing a pinion gear as a single body is shown. Figure 7 A perspective view showing an internal gear as a single body is shown. Figure 8 A perspective view showing three helical gears is shown, Fig. 9 A three-dimensional diagram showing the bracket as a single body is shown, Fig.10 An exploded perspective view showing the sway adjustment mechanism.

[0099] [Overview of planetary gear reduction mechanism]

[0100] Figures 1 to 5 The planetary gear reduction mechanism 10 shown is used, for example, for driving a joint of a robot. Furthermore, an electric motor (not shown) as a driving source is provided on the input side (lower side in the figure) of the planetary gear reduction mechanism 10 so as to be able to transmit power, and a driving mechanism (not shown) of a robot as a driven object is provided on the output side (upper side in the figure) of the planetary gear reduction mechanism 10 so as to be able to transmit power.

[0101] Specifically, the rotating shaft 31 of the planetary gear reduction mechanism 10 is rotated by the electric motor, and the bracket 60 of the planetary gear reduction mechanism 10 drives the driving mechanism of the robot. In addition, the planetary gear reduction mechanism 10 reduces the rotation of the rotating shaft 31 to increase the torque, and outputs the rotational force obtained by the increase in torque from the bracket 60.

[0102] Thus, even if the driving source is a small electric motor, the planetary gear reduction mechanism 10 can transmit a large driving torque to the driving mechanism of the robot. Thus, the electric motor can be miniaturized and can be easily installed inside the arm of the robot with a small installation space.

[0103] Furthermore, the planetary gear reduction mechanism 10 of this embodiment is not limited to the use in driving joints of robots, but may also be applied to small-sized driving systems mounted on vehicles such as automobiles, such as power sliding door devices and power window devices.

[0104] [case]

[0105] The planetary gear reduction mechanism 10 includes a housing 20 that forms the outer contour 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, which is installed on one axial side (lower side in the figure) of the housing body 21 and is formed in an annular shape. In addition, the housing body 21 and the ring member 22 are both made of aluminum, thereby achieving the overall weight reduction of the planetary gear reduction mechanism 10.

[0106] 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, which are integrally provided on one axial side of the cylindrical portion 21a and protrude radially outward of the cylindrical portion 21a. In addition, each of the total of eight first flange portions 21b is provided with an insertion hole 21c for inserting a fixing bolt (not shown).

[0107] 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 inwardly of the cylindrical portion 21a. Furthermore, an outer ring (outer race) of the first ball bearing BB1 is mounted radially inwardly of the second flange portion 21d. In addition, 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 ring gear 40.

[0108] In this manner, the second flange portion 21 d of the case body 21 has a function of supporting both the first ball bearing BB1 and the ring gear 40 .

[0109] Here, the first ball bearing BB1 rotatably supports the other axial side (upper side in the figure) of the bracket 60. Specifically, the inner ring (inner race) of the first ball bearing BB1 is installed on the output side cylindrical portion 66 (see Fig. 9 )'s outer periphery.

[0110] In addition, a plurality of threaded holes 21e are provided on the other axial side (upper side in the figure) of the second flange portion 21d. Fixing screws (not shown) are screwed into these threaded holes 21e, and the fixing screws are used to fix the planetary gear reduction mechanism 10 to a fixing portion (not shown) inside the arm of a robot or the like.

[0111] 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 in a manner protruding radially outward. These third flange portions 22b are provided corresponding to the first flange portion 21b of the housing main body 21. In addition, each third flange portion 22b is provided with an internal threaded hole 22c for screwing a fixing bolt (not shown).

[0112] In addition, in the axial direction of the housing 20, a total of eight fourth flange portions 42 provided on the ring gear 40 are sandwiched between the first flange portion 21b and the third flange portion 22b forming the housing 20. Thus, the speed reducer SD is accommodated and fixed inside the housing 20 by inserting fixing bolts (not shown) through the insertion holes 21c of the first flange portion 21b and the insertion holes 42a of the fourth flange portion 42 and screwing them into the internal threaded holes 22c of the third flange portion 22b.

[0113] In addition, the outer ring of the second ball bearing BB2 is mounted radially inside the ring member 22. That is, the ring member 22 has the function of supporting the second ball bearing BB2 and fixing the ring gear 40 inside the housing 20.

[0114] Here, the second ball bearing BB2 rotatably supports one axial side (lower side in the figure) of the bracket 60. Specifically, the inner ring of the second ball bearing BB2 is mounted on the input side cylindrical portion 65 (see Fig. 9 )'s outer periphery.

[0115] In addition, a total of four positioning protrusions P (see FIG. 1 ) are integrally provided on the other axial side (upper side in the figure) of the ring member 22. Fig.13 ). These positioning protrusions P protrude toward the ring gear 40 in the axial direction of the ring member 22 and engage with the engaging recesses (not shown) of the ring gear 40. As a result, the ring member 22 can be easily positioned relative to the ring gear 40 (improvement of assembly performance).

[0116] In addition, the first ball bearing BB1 and the second ball bearing BB2 that support the bracket 60 on both sides in the axial direction are respectively made of ball bearings of the same size and specification. In addition, the first ball bearing BB1 and the second ball bearing BB2 are the largest ball bearings provided on the planetary gear reduction mechanism 10.

[0117] [Overview of the reducer]

[0118] like Figures 3 to 9 As shown, the planetary gear reduction mechanism 10 has a plurality of gears. Specifically, the reducer SD accommodated in the housing 20 includes a pinion 30, a ring gear 40, a total of three planetary gears 50, and a carrier 60 that holds these planetary gears 50. That is, the reducer SD is a planetary reducer.

[0119] [Small gear]

[0120] like Figures 3 to 6As shown, the pinion gear 30 is integrally provided on the other axial side (upper side in the figure) of the rotating shaft 31. Moreover, on one axial side (lower side in the figure) of the rotating shaft 31, it is connected to the output shaft (not shown) of the electric motor as the driving source in a manner capable of transmitting power. Thus, the pinion gear 30 rotates at a predetermined rotational speed in a predetermined rotational direction as the electric motor is driven to rotate.

[0121] In addition, the pinion gear 30 corresponds to the sun gear in the present invention.

[0122] The helical teeth 32 are integrally provided on the outer circumference of the pinion gear 30. The axial length of the pinion gear 30 (helical teeth 32) is slightly greater than the axial length of the planetary gear 50. Thus, the helical teeth 32 can mesh with the planetary gear 50 reliably.

[0123] In addition, the spiral tooth 32 corresponds to one tooth in the present invention.

[0124] The spiral teeth 32 are connected in a spiral shape in the axial direction of the rotating shaft 31, and only one spiral tooth 32 is provided on the pinion 30. That is, the number of teeth of the pinion 30 is "1". In addition, the cross-sectional shape of the spiral tooth 32 is approximately semicircular, and the spiral tooth 32 enters (meshes with) the meshing recess 51a of the planetary gear 50 (refer to Figure 8 ).

[0125] Thus, by setting the number of teeth of the pinion 30 to "1", the transmission efficiency of the gear can be improved [%], and a large reduction ratio can be obtained while being small. Therefore, the electric motor as a driving source can be made smaller and more energy-efficient.

[0126] [Internal gear]

[0127] like Figure 3 and Figure 7 As shown, the internal gear 40 is fixed to the radial inner side of the cylindrical portion 21a forming the housing body 21. Specifically, the internal gear 40 is clamped by the housing body 21 and the ring member 22 in the axial direction of the planetary gear reduction mechanism 10. In addition, the internal gear 40 includes: a cylindrical body 41 formed in a substantially cylindrical shape; and a total of 8 fourth flange portions 42, which protrude radially outward from the cylindrical body 41 on one side of the axial direction of the cylindrical body 41.

[0128] The cylindrical body 41 is arranged radially outside the pinion gear 30, and a gear forming portion 43 is provided radially inside the cylindrical body 41. The gear forming portion 43 of the cylindrical body 41 is integrally provided with a plurality of internal teeth 43a having a substantially semicircular cross-sectional shape similar to the helical teeth 32 of the pinion gear 30. Here, the plurality of internal teeth 43a are inclined at a predetermined angle relative to the axial direction of the cylindrical body 41, thereby being able to mesh with the meshing recess 51a of the planetary gear 50 (see Figure 8 ).

[0129] In addition, the ring gear 40 corresponds to the internal gear in the present invention.

[0130] The fourth flange 42 provided on the ring gear 40 corresponds to the first flange 21b of the housing body 21 and the third flange 22b of the ring member 22. The eight fourth flanges 42 each have an insertion hole 42a through which a fixing bolt (not shown) is inserted.

[0131] Thus, the fourth flange portion 42 is sandwiched between the first flange portion 21 b and the third flange portion 22 b , and the ring gear 40 is firmly fixed in both the axial direction and the circumferential direction with respect to the housing 20 without rattling.

[0132] [Planetary gear]

[0133] like Figure 3 and Figure 8 As shown, a total of three planetary gears 50 are arranged between the pinion gear 30 and the ring gear 40 in the radial direction of the planetary gear reduction mechanism 10. Each planetary gear 50 is arranged at equal intervals (120 degree intervals) relative to the circumferential direction of the pinion gear 30 and the ring gear 40, and meshes with both the pinion gear 30 and the ring gear 40.

[0134] In addition, the planetary gear 50 corresponds to the planetary gear in the present invention.

[0135] The planetary gear 50 is formed in a substantially cylindrical shape, and a gear forming portion 51 is provided on the radially outer side thereof. A plurality of meshing recesses 51a are provided in the gear forming portion 51 of the planetary gear 50 in a manner arranged in the circumferential direction thereof. 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 the inside of the meshing recesses 51a and mesh with each other.

[0136] Here, the planetary gear 50 has a meshing recess 51 a that is inclined with respect to the axial direction of the planetary gear 50 , and may also be called a helical gear.

[0137] Therefore, each planetary gear 50 rotates between the pinion gear 30 rotated by an electric motor (not shown) and the ring 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 substantially semicircular.

[0138] A third ball bearing BB3 and a fourth ball bearing BB4 are provided on the radial 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. Moreover, the outer rings of the third ball bearing BB3 and the fourth ball bearing BB4 are installed on the radial inner side of the planetary gear 50.

[0139] Furthermore, the third ball bearing BB3 and the fourth ball bearing BB4 provided on both sides of the planetary gear 50 in the axial direction respectively support the planetary gear 50 rotatably, and correspond to the ball bearings in the present invention.

[0140] The third ball bearing BB3 and the fourth ball bearing BB4 are ball bearings of the same size and specification. In addition, the third ball bearing BB3 and the fourth ball bearing BB4 are smaller ball bearings than the first ball bearing BB1 and the second ball bearing BB2 that rotatably support the bracket 60 .

[0141] A total of three planetary gears 50 are rotatably supported by the support shaft 52. Specifically, in the mounting bracket assembly CA (refer to Fig.12 ), the support shaft 52 is inserted into the inner rings of the third ball bearing BB3 and the fourth ball bearing BB4 installed on the planetary gear 50. Moreover, the axial sides of the support shaft 52 are respectively fixed to the first support shaft fixing hole 64a and the second support shaft fixing hole 64b provided on the bracket 60.

[0142] In addition, a first washer WS1 is provided on one axial side (lower side in the figure) of the third ball bearing BB3 and on the other axial side (upper side in the figure) of the fourth ball bearing BB4. Thus, the planetary gear 50 equipped with the third ball bearing BB3 and the fourth ball bearing BB4 can smoothly rotate relative to the bracket 60 and the support shaft 52 without shaking.

[0143] [bracket]

[0144] like Figure 3 and Fig. 9As shown, the bracket 60 is formed into a substantially cylindrical shape by cutting aluminum material, etc. The bracket 60 includes a cylindrical body 61, and a total of three gear support parts 62 are provided on the cylindrical body 61. Each gear support part 62 has a function of supporting the planetary gear 50 rotatably.

[0145] Here, the carrier 60 rotatably supports a total of three planetary gears 50 , and corresponds to a planetary carrier in the present invention.

[0146] The gear support portion 62 is arranged at equal intervals (120 degree intervals) in the circumferential direction of the cylindrical body portion 61, and includes a connecting hole 62a that connects the radial inner side and the radial outer side of the cylindrical body portion 61. The connecting hole 62a is formed in a substantially square shape when the bracket 60 is viewed from the side. Moreover, the planetary gear 50 is rotatably accommodated in the connecting hole 62a with a small gap therebetween.

[0147] In addition, the carrier 60 is one of the parts that require particularly high processing accuracy among the parts that form the planetary gear reduction mechanism 10 in order to allow the planetary gear 50 to rotate smoothly without rattling.

[0148] In addition, a first base 63a and a second base 63b are provided on both sides of the axial connecting hole 62a of the bracket 60 to support both axial sides of the planetary gear 50. Specifically, the first base 63a is arranged on one axial side of the bracket 60 (the lower side in the figure), and the second base 63b is arranged on the other axial side of the bracket 60 (the upper side in the figure).

[0149] Furthermore, the first washers WS1 provided on both axial sides of the planetary gear 50 are in contact with the first base 63a and the second base 63b, respectively. Thus, the planetary gear 50 can rotate smoothly without rattling in the axial direction of the carrier 60.

[0150] 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 bracket 60. An insertion hole 65a for inserting the rotating shaft 31 (pinion gear 30) is provided on the radially inner side of the input side cylindrical portion 65, and a fifth ball bearing BB5 for rotatably supporting the rotating shaft 31 is fixed to the insertion hole 65a.

[0151] Specifically, if Figure 5 As shown, the insertion hole 65a is provided with a bearing fixing portion 65c formed in a stepped shape. In addition, the fifth ball bearing BB5 includes an inner ring IR5 and an outer ring OR5. And the outer ring OR5 of the fifth ball bearing BB5 is supported by the bearing fixing portion 65c of the insertion hole 65a.

[0152] In contrast, the inner ring IR5 of the fifth ball bearing BB5 is fixed by press-fitting to the substantially central portion of the rotating shaft 31 in the axial direction (near the pinion 30). That is, the fifth ball bearing BB5 cannot move to either one axial side or the other axial side of the rotating shaft 31.

[0153] Furthermore, if Figure 3 and Figure 5 As shown, one axial side of the input side cylindrical portion 65 is covered by a cover member 67 formed in a substantially annular shape. The cover member 67 presses the outer ring OR5 of the fifth ball bearing BB5, thereby preventing the fifth ball bearing BB5 from falling off from the input side cylindrical portion 65. In other words, the cover member 67 prevents the rotating shaft 31 to which the fifth ball bearing BB5 is fixed from falling off from the bracket 60.

[0154] Here, the bearing fixing portion 65 c cooperates with the cover member 67 to support the fifth ball bearing BB5 in a manner that prevents movement in the axial direction of the rotating shaft 31 , and thus corresponds to the first bearing supporting portion in the present invention.

[0155] Furthermore, the cover member 67 is provided with a total of three screw insertion holes 67a (see Figure 2 and Fig.14 ), a total of three threaded holes 65b are provided on one axial side of the input side cylindrical portion 65. And, fixing screws (not shown) for fixing the cover member 67 to the input side cylindrical portion 65 are screwed into the total of three threaded holes 65b.

[0156] In addition, the fifth ball bearing BB5 is provided on one side (lower side in the figure) of the pinion 30 in the axial direction of the rotating shaft 31, and is equivalent to the first bearing in the present invention. In addition, the inner ring IR5 of the fifth ball bearing BB5 is equivalent to the first inner ring in the present invention, and the outer ring OR5 of the fifth ball bearing BB5 is equivalent to the first outer ring in the present invention.

[0157] In addition, the inner ring of the second ball bearing BB2 is installed on the radially outer side of the input side cylindrical portion 65, and the inner ring of the second ball bearing BB2 abuts against the first step portion ST1 between the tubular body portion 61 and the input side cylindrical portion 65 from one axial side (see Fig. 9 ).

[0158] Furthermore, a first support shaft fixing hole 64a is provided in a portion of the input side cylindrical portion 65 where the first base 63a is provided so as to extend in the axial direction of the bracket 60. Three first support shaft fixing holes 64a are provided corresponding to the first base 63a, and are arranged at equal intervals (120 degree intervals) in the circumferential direction of the cylindrical body portion 61. Moreover, the first support shaft fixing hole 64a penetrates both the first base 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 installed in the first support shaft fixing hole 64a.

[0159] In addition, 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 bracket 60. A bearing support portion 66a is provided on the radially inner side of the output side cylindrical portion 66 so as to penetrate the output side cylindrical portion 66. Figure 4 As shown, the bearing support portion 66a has a bearing guide portion 66c and an internal thread portion 66d, wherein the bearing guide portion 66c is arranged on one axial side of the bearing support portion 66a (the lower side in the figure), and the internal thread portion 66d is arranged on the other axial side of the bearing support portion 66a (the upper side in the figure).

[0160] Furthermore, the sixth ball bearing BB6 is mounted on the bearing guide portion 66c to rotatably support the other axial side of the rotating shaft 31, and the sixth ball bearing BB6 is movable in the axial direction relative to the bearing guide portion 66c. That is, the bearing guide portion 66c of the bearing support portion 66a supports the sixth ball bearing BB6 so that it can move in the axial direction of the rotating shaft 31.

[0161] Furthermore, the bearing guide portion 66c forming the bearing support portion 66a corresponds to a second bearing support portion in the present invention.

[0162] Furthermore, a play adjustment member 68 is provided on the internal thread portion 66d of the bearing support portion 66a, and the play adjustment member 68 is used to adjust the play (eliminate the play) of the rotating shaft 31 in the axial direction relative to the bracket 60. Specifically, the play adjustment member 68 is screwed to the internal thread portion 66d. In this way, the bracket 60 is equipped with a play adjustment mechanism BA for eliminating the play of the rotating shaft 31.

[0163] Furthermore, the internal thread portion 66d forming the bearing support portion 66a also corresponds to the second bearing support portion in the present invention.

[0164] In addition, a second support shaft fixing hole 64b is provided at a portion of the output side cylindrical portion 66 where the second base 63b is provided so as to extend in the axial direction of the bracket 60. Three second support shaft fixing holes 64b are provided corresponding to the second base 63b, and are arranged at equal intervals (120 degree intervals) in the circumferential direction of the cylindrical body 61. Moreover, the second support shaft fixing hole 64b penetrates both the second base 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 installed in the second support shaft fixing hole 64b.

[0165] Here, the support shaft 52 is inserted into the first support shaft fixing hole 64a to a degree that does not cause shaking, and is fixed in the second support shaft fixing hole 64b by being pressed. Fig.13 ) when the support shaft 52 is inserted into the first support shaft fixing hole 64a and the second support shaft fixing hole 64b, thereby improving the assembly performance.

[0166] In addition, if Fig. 9 As shown in the figure, a plurality of internal thread holes 66b are provided on the other axial side (upper side in the figure) of the output side cylindrical portion 66. These internal thread holes 66b extend in the axial direction of the bracket 60. Furthermore, fixing screws (not shown) for fixing a driving mechanism (not shown) of a robot as a driven object are screwed into the internal thread holes 66b.

[0167] Furthermore, the inner ring of the first ball bearing BB1 is installed on the radially outer side of the output side cylindrical portion 66, and the inner ring of the first ball bearing BB1 abuts against the second step portion ST2 (see FIG. 1 ) between the tubular body portion 61 and the output side cylindrical portion 66 from the other axial side. Fig. 9 Specifically, a third washer WS3 is provided between the inner ring of the first ball bearing BB1 and the second step portion ST2 (see Fig.13 ), the inner ring of the first ball bearing BB1 abuts against the second step portion ST2 via the third washer WS3.

[0168] [Sway adjustment mechanism]

[0169] like Figure 3 , Figure 4 and Fig.10 As shown, the play adjustment mechanism BA provided in the output side cylindrical portion 66 includes a second washer WS2 , a sixth ball bearing BB6 , and a play adjustment member 68 .

[0170] The sixth ball bearing BB6 includes an inner ring IR6 and an outer ring OR6. The outer ring OR6 of the sixth ball bearing BB6 is mounted on the bearing guide portion 66c forming the bearing support portion 66a. Thus, the sixth ball bearing BB6 is movable in the axial direction relative to the bearing support portion 66a.

[0171] On the other hand, the inner ring IR6 of the sixth ball bearing BB6 is installed on the other axial side of the rotating shaft 31 ( Figure 4 Here, as shown in FIG. Figure 6 As shown, the bearing mounting portion 31 a is formed in a cylindrical shape having a smaller diameter than the main body portion of the rotating shaft 31 , and a support step 31 b is provided between the bearing mounting portion 31 a and the pinion gear 30 .

[0172] Moreover, one axial side of the inner ring IR6 abuts against the support step 31b from the other axial side via the second washer WS2. That is, one axial side of the inner ring IR6 is supported by the support step 31b via the second washer WS2. As a result, the sixth ball bearing BB6 cannot move to one axial side of the rotating shaft 31 relative to the rotating shaft 31.

[0173] In this manner, the fifth ball bearing BB5 and the sixth ball bearing BB6 are provided so as not to be close to each other in the axial direction of the rotating shaft 31 .

[0174] In addition, the support step 31b corresponds to the step portion in the present invention.

[0175] In addition, the second washer WS2 has a function of eliminating play between the inner ring IR6 of the sixth ball bearing BB6 and the pinion gear 30 to allow the pinion gear 30 (rotation shaft 31 ) to rotate smoothly.

[0176] Here, the sixth ball bearing BB6 adopts a radial thrust ball bearing (angular ball bearing). As a result, the sixth ball bearing BB6 presses the rotating shaft 31 to one axial side (the lower side in the figure) while receiving the axial force from the sway adjustment member 68. As a result, the sway of the rotating shaft 31 relative to the bracket 60 can be suppressed. Therefore, the pinion 30 and the planetary gear 50 are properly meshed, and the transmission efficiency [%] of these gears is improved. As a result, the quietness of the planetary gear reduction mechanism 10 during operation is improved.

[0177] In addition, the sixth ball bearing BB6 is provided on the other side (upper side in the figure) of the pinion 30 in the axial direction of the rotating shaft 31, and thus corresponds to the second bearing in the present invention. In addition, the inner ring IR6 of the sixth ball bearing BB6 corresponds to the second inner ring in the present invention, and the outer ring OR6 of the sixth ball bearing BB6 corresponds to the second outer ring in the present invention.

[0178] Here, the play adjustment member 68 includes an adjustment body portion 68 a formed in a substantially disc shape, and a cylindrical pressing portion 68 b integrally provided on one axial side (the sixth ball bearing BB6 side) of the adjustment body portion 68 a .

[0179] Then, by rotating the adjustment main body 68a in the clockwise direction (the direction of arrow A10) relative to the internal threaded hole 66b, the shake adjustment member 68 moves toward one side in the axial direction ( Figure 4 Thus, the pressing portion 68b in contact with the outer ring OR6 of the sixth ball bearing BB6 presses the outer ring OR6 toward one axial side. In contrast, by rotating the adjustment body portion 68a in the counterclockwise direction (the direction opposite to the direction of arrow A10) relative to the internal threaded hole 66b, the rocking adjustment member 68 moves toward the other axial side ( Figure 4 ) moves to the upper side of the

[0180] In this way, the other axial side of the outer ring OR6 of the sixth ball bearing BB6 is supported by the pressing portion 68b of the play adjustment member 68. In addition, the play adjustment member 68 is a member provided on the internal thread portion 66d of the bearing support portion 66a and presses the sixth ball bearing BB6 toward the side where the fifth ball bearing BB5 is provided, and is equivalent to the pressing member in the present invention.

[0181] [Assembly process]

[0182] Next, use Figures 11 to 15 The assembly process of the planetary gear reduction mechanism 10 formed as described above will be described in detail.

[0183] Fig.11 A three-dimensional diagram showing the assembly process of the bracket assembly is shown. Fig.12 A perspective view showing the assembly process of the internal gear relative to the carrier assembly is shown. Fig.13 A perspective view showing the assembly process of the housing body and the ring member is shown. Fig.14 A perspective view showing the assembly process of the pinion gear and the shake adjustment mechanism is shown. Fig.15 A graph comparing the transmission efficiency [%] of gears is shown.

[0184] [Assembly of bracket assembly]

[0185] like Fig.11 As shown, the bracket assembly CA is first assembled. Specifically, the bracket 60, a total of three planetary gears 50, and a total of three support shafts 52 manufactured through another manufacturing process are prepared. Fig.11 In the figure, for the sake of easy observation, one planetary gear 50 and one support shaft 52 are shown respectively.

[0186] Then, if Figure 8 As shown by arrow A1, the planetary gear 50 faces the connecting hole 62a from the radial outer side of the bracket 60. At this time, the third ball bearing BB3 and the fourth ball bearing BB4 (see FIG. 1 ) are pre-installed on the radial inner side of the planetary gear 50. Figure 3). In addition, a first washer WS1 is installed on each of the third ball bearing BB3 and the fourth ball bearing BB4 (see Figure 3 ).

[0187] Then, the planetary gear 50 is inserted into the communication hole 62a, and Fig.11 As shown by arrow A2, the support shaft 52 faces the other axial side of the bracket 60. At this time, the input side cylindrical portion 65 of the bracket 60 is arranged on one axial side (lower side in the figure), and the output side cylindrical portion 66 of the bracket 60 is arranged on the other axial side (upper side in the figure).

[0188] Then, the support shaft 52 is inserted into the second support shaft fixing hole 64b and the first support shaft fixing hole 64a in sequence. In addition, the support shaft 52 is inserted into the first support shaft fixing hole 64a, and the support shaft 52 is pressed into the second support shaft fixing hole 64b. Thus, the insertion load of the support shaft 52 does not need to be too large, so that the bracket assembly CA can be easily assembled.

[0189] Then, the planetary gear 50 is mounted to the communication hole 62a twice, thereby completing the bracket assembly CA (see FIG. Fig.12 ) assembly work.

[0190] [Assembly of the internal gear to the carrier assembly]

[0191] Then, if Fig.12 As shown in FIG. 1 , the ring gear 40 manufactured through another manufacturing process is prepared, and the operation of assembling the ring gear 40 to the already assembled carrier assembly CA is performed.

[0192] Specifically, as shown by arrow A3 in the figure, the ring gear 40 faces the other axial side of the carrier assembly CA, that is, the output side cylindrical portion 66 side (upper side in the figure). At this time, the fourth flange portion 42 side of the ring gear 40 in the axial direction faces the carrier assembly CA.

[0193] Then, the carrier assembly CA is arranged so as to overlap the ring gear 40 on the radially outer side. At this time, the planetary gear 50 of the carrier assembly CA can smoothly rotate relative to the carrier 60. Therefore, the inner teeth 43a of the ring gear 40 and the meshing recessed portion 51a of the planetary gear 50 mesh smoothly with each other.

[0194] Thereby, the assembly work of the ring gear 40 to the carrier assembly CA is completed.

[0195] [Assembly of the housing body and the ring member]

[0196] Then, if Fig.13As shown, the housing body 21, the ring member 22 and the third washer WS3 manufactured through another manufacturing process are prepared. In addition, the first ball bearing BB1 is pre-installed in the housing body 21, and the second ball bearing BB2 is pre-installed in the ring member 22.

[0197] Then, as shown by arrow A4 in the figure, the third washer WS3 is installed on the output side cylindrical portion 66 of the bracket 60. Then, as shown by arrow A5 in the figure, the housing body 21 is installed in a manner overlapping the radial outer side of the ring gear 40. At this time, the first flange portion 21b side of the housing body 21 in the axial direction is directed toward the ring gear 40.

[0198] Then, as shown by arrow A6 in the figure, the ring member 22 (with the second ball bearing BB2 installed) is installed on the input side cylindrical portion 65 of the bracket 60. At this time, the side of the ring member 22 provided with the positioning protrusion P is directed toward the ring gear 40. Then, while the second ball bearing BB2 is installed on the input side cylindrical portion 65, the positioning protrusion P of the ring member 22 is engaged with the engaging recess (not shown) of the ring gear 40.

[0199] Then, the fixing bolts (not shown) are inserted into the insertion holes 21c of the first flange portion 21b and the insertion holes 42a of the fourth flange portion 42, and the fixing bolts are screwed into the internal threaded holes 22c of the third flange portion 22b. Thus, the reducer SD is accommodated inside the housing 20, and the assembly of the housing body 21 and the ring member 22 is completed.

[0200] [Assembly of pinion gear and shake adjustment mechanism]

[0201] Then, if Fig.14 As shown, a rotating shaft 31 having a pinion 30 manufactured through another manufacturing process and a cover member 67 are prepared. In addition, a fifth ball bearing BB5 is fixed in advance to the rotating shaft 31. In addition, a second washer WS2, a sixth ball bearing BB6, and a shake adjustment member 68 forming a shake adjustment mechanism BA are also prepared.

[0202] Then, as shown by arrow A7 in the figure, the pinion gear 30 is directed toward the input side cylindrical portion 65 of the carrier 60 (see Figure 3 Then, the pinion gear 30 is inserted into a total of three planetary gears 50 (see Figure 8 ). At this time, the planetary gear 50 can smoothly rotate relative to the carrier 60. Therefore, while each planetary gear 50 rotates, the helical teeth 32 of the pinion 30 and the meshing recessed portion 51a (see Figure 8 ) mesh smoothly with each other.

[0203] Then, the outer ring OR5 of the fifth ball bearing BB5 is mounted on the bearing fixing portion 65c of the insertion hole 65a (see Figure 5 ). In addition, Fig.14 As shown by arrow A8, the cover member 67 is fixed to the input side cylindrical portion 65 (see Figure 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 of the input-side cylindrical portion 65 (see Figure 3 )middle.

[0204] Thus, the outer ring OR5 of the fifth ball bearing BB5 is fixed to the bearing fixing portion 65 c , and the rotating shaft 31 (pinion gear 30 ) can be prevented from coming off the bracket 60 .

[0205] Next, as shown by arrow A9 in the figure, the second washer WS2 is placed in the bearing support portion 66a of the output side cylindrical portion 66, and the second washer WS2 is placed on the support step 31b of the rotating shaft 31. Thereafter, the sixth ball bearing BB6 is placed in the bearing support portion 66a of the output side cylindrical portion 66, and the inner ring IR6 is mounted on the bearing mounting portion 31a of the rotating shaft 31. Then, the play adjustment member 68 is screwed to the internal thread portion 66d of the bearing support portion 66a.

[0206] Thus, one axial side (the fifth ball bearing BB5 side) of the inner ring IR6 of the sixth ball bearing BB6 is supported by the support step 31b via the second washer WS2. In addition, the other axial side (the play adjustment member 68 side) of the outer ring OR6 of the sixth ball bearing BB6 is supported by the pressing portion 68b of the play adjustment member 68.

[0207] Then, if Figure 4 and Fig.14 As shown by the arrow A10, the shake adjustment member 68 is rotated in the clockwise direction with a predetermined tightening torque. Then, the shake adjustment member 68 moves to one side in the axial direction (towards the rotating shaft 31), and the sixth ball bearing BB6 also moves to one side in the axial direction. Specifically, the outer ring OR6 is pressed to one side in the axial direction by the pressing portion 68b. As a result, the outer ring OR6 moves to one side in the axial direction. Figure 4 Move in the direction of arrow M1.

[0208] In addition, as the outer ring OR6 moves in the direction of the arrow M1, the inner ring IR6 of the sixth ball bearing BB6 also moves in the same direction as the outer ring OR6, that is, in the direction of the arrow M2 (see Figure 4 During this period, the shaking of the sixth ball bearing BB6 is absorbed (eliminated).

[0209] Then, the inner ring IR6 presses the support step 31b to one side in the axial direction via the second washer WS2, so that Figure 5As shown by the arrow M2, the rotating shaft 31 is also pressed to one side in the axial direction. At this time, the play between the inner ring IR6, the second washer WS2 and the pinion 30 in the axial direction of the rotating shaft 31 is also eliminated.

[0210] Then, as the rotating shaft 31 moves toward one side in the axial direction, the inner ring IR5 of the fifth ball bearing BB5 fixed to the rotating shaft 31 is Figure 5 As shown by the arrow M3, it moves axially to one side.

[0211] In addition, as the inner ring IR5 moves in the direction of the arrow M3, the outer ring OR5 of the fifth ball bearing BB5 also moves in the same direction as the inner ring IR5, that is, in the direction of the arrow M4 (see Figure 5 Then, the outer ring OR5 abuts against the cover member 67 from the other axial side. During this period, the play of the fifth ball bearing BB5 is absorbed (eliminated).

[0212] In this way, by rotating the play adjustment member 68 in the clockwise direction at a predetermined tightening torque, the play of the fifth ball bearing BB5 and the sixth ball bearing BB6 can be eliminated, and the play of the outer ring OR5 of the fifth ball bearing BB5 relative to the bearing fixing portion 65c can also be eliminated. Therefore, the rotating shaft 31 does not play relative to the bracket 60 in the axial direction thereof.

[0213] However, if the tightening torque of the play adjustment member 68 is too large, the rotation resistance of the fifth and sixth ball bearings BB5 and BB6 will increase. Therefore, the tightening torque of the play adjustment member 68 is set not to exceed the allowable axial force of the fifth and sixth ball bearings BB5 and BB6.

[0214] As a result, the assembly work of the pinion gear 30 and the play adjustment mechanism BA is completed, and the play of the rotating shaft 31 in the axial direction relative to the carrier 60 (planetary gear reduction mechanism 10) is eliminated. As a result, the assembly work of the planetary gear reduction mechanism 10 is finally completed.

[0215] In addition, the transmission efficiency [%] of the pinion gear 30 and the planetary gear 50 with respect to the rotational drive of the rotating shaft 31 in the forward and reverse directions is Fig.15 The results are shown in the graph. That is, when the rotating shaft 31 shakes in the axial direction, that is, in the case of the "comparative example" with shaking, there is a relatively large difference in the transmission efficiency [%] in the clockwise direction (dotted arrow CW) and the counterclockwise direction (solid arrow CCW). This means that the output characteristics of the planetary gear reduction mechanism 10 change significantly depending on the rotation direction of the rotating shaft 31. Therefore, problems such as being unsuitable for joint driving of robots that require precise drive control may arise.

[0216] In contrast, when the rotating shaft 31 does not wobble in the axial direction, that is, in the case of the "present embodiment" without wobble, the transmission efficiency [%] becomes close to each other in the clockwise direction (dashed arrow CW) and the counterclockwise direction (solid arrow CCW) compared to the "comparative example". Specifically, the difference in transmission efficiency [%] can be converged to approximately half or less relative to the "comparative example". As a result, it is possible to suppress the situation in which the output characteristics of the planetary gear reduction mechanism 10 vary significantly depending on the rotation direction of the rotating shaft 31, and stable operation can be performed. Therefore, it is possible to fully cope with even the joint drive of a robot that requires precise drive control.

[0217] Furthermore, in the planetary gear reduction mechanism 10, as described above, only one helical tooth 32 is provided on the pinion 30, and the cross-sectional shape of the helical tooth 32 is substantially semicircular. Therefore, when the planetary gear reduction mechanism 10 is operating, each planetary gear 50 tries to move away from the pinion 30 with a relatively strong force. That is, the pinion 30 is prone to rotational vibration.

[0218] In contrast, in the planetary gear reduction mechanism 10, as described above, the pinion 30 is supported by the fifth ball bearing BB5 and the sixth ball bearing BB6 having high rigidity, so that the rotational vibration of the pinion 30 can be effectively suppressed. Therefore, the planetary gear reduction mechanism 10 can perform stable operation even when subjected to a relatively large load (large torque).

[0219] As described in detail above, according to the planetary gear reduction mechanism 10 of the present embodiment, there is: a fifth ball bearing BB5, which is arranged on one side of the pinion 30 in the axial direction of the rotating shaft 31, and supports the rotating shaft 31 freely for rotation; a sixth ball bearing BB6, which is arranged on the other side of the pinion 30 in the axial direction of the rotating shaft 31, and supports the rotating shaft 31 freely for rotation; a bearing fixing portion 65c, which is arranged on the bracket 60, and supports the fifth ball bearing BB5 in a manner that cannot be moved in the axial direction of the rotating shaft 31; and a bearing guide portion 66c, which is arranged on the bracket 60, and supports the sixth ball bearing BB6 in a manner that can be moved in the axial direction of the rotating shaft 31, the fifth ball bearing BB5 and the sixth ball bearing BB6 are arranged in a manner that cannot approach each other relative to the axial direction of the rotating shaft 31, and a shake adjustment member 68 is provided on the internal thread portion 66d to press the sixth ball bearing BB6 toward the side where the fifth ball bearing BB5 is provided.

[0220] Thus, by adjusting the shake adjustment member 68, the shake of the fifth ball bearing BB5 and the sixth ball bearing BB6 can be eliminated, and the shake of the fifth ball bearing BB5 relative to the bearing fixing portion 65c can be eliminated. Therefore, the rotating shaft 31 can be made relative to the bracket 60 without shaking in the axial direction thereof, and the transmission efficiency [%] of the gear can be optimized. Thus, a planetary gear reduction mechanism 10 capable of stable operation can be realized.

[0221] Furthermore, according to the planetary gear reduction mechanism 10 of the present embodiment, the fifth ball bearing BB5 includes an inner ring IR5 and an outer ring OR5 . The inner ring IR5 is fixed to the rotating shaft 31 , and the outer ring OR5 is supported by the bearing fixing portion 65 c .

[0222] Thus, the axial play of the fifth ball bearing BB5 can be eliminated simply by adjusting the play adjustment member 68 to apply an axial force to the rotating shaft 31 .

[0223] Furthermore, according to the planetary gear reduction mechanism 10 of this embodiment, the sixth ball bearing BB6 includes an inner ring IR6 and an outer ring OR6, one axial side of the inner ring IR6 is supported by a support step 31b arranged on the rotating shaft 31, and the other axial side of the outer ring OR6 is supported by a pressing portion 68b of the shake adjustment member 68.

[0224] Thus, the axial play of the sixth ball bearing BB6 can be eliminated simply by adjusting the play adjusting member 68 to apply an axial force to the outer ring OR6.

[0225] Furthermore, according to the planetary gear reduction mechanism 10 of the present embodiment, the play adjustment member 68 is screwed to the internal thread portion 66 d of the bearing support portion 66 a .

[0226] Therefore, the shaking of the fifth ball bearing BB5, the sixth ball bearing BB6 and the shaking of the fifth ball bearing BB5 relative to the bearing fixing portion 65c can be easily eliminated (operability is improved) only by managing the screw insertion amount of the shaking adjustment member 68 (managing the tightening torque).

[0227] Furthermore, according to the planetary gear reduction mechanism 10 of the present embodiment, both axial sides of the planetary gear 50 are supported by the third ball bearing BB3 and the fourth ball bearing BB4 , respectively.

[0228] This can effectively suppress the rattling of the planetary gear 50 relative to the carrier 60. This can also optimize the transmission efficiency [%] of the gear, and further realize the planetary gear reduction mechanism 10 capable of more stable operation.

[0229] Furthermore, according to the planetary gear reduction mechanism 10 of the present embodiment, the pinion gear 30 has only the helical teeth 32 that are helically connected in the axial direction of the rotating shaft 31 .

[0230] As a result, the transmission efficiency of the gear can be improved [%], and a large reduction ratio can be obtained while being small. As a result, the electric motor as a driving source can be made smaller and more energy-efficient.

[0231] Furthermore, according to the planetary gear reduction mechanism 10 of the present embodiment, by adjusting the sway adjustment member 68, the dimensional errors of different parts in each product can be absorbed and the transmission efficiency [%] of the gears in each product can be optimized. Therefore, the parts management can be simplified, and operations such as reassembly can be abolished. As a result, the manufacturing energy used to manufacture the planetary gear reduction mechanism 10 can be saved, and in particular, the Sustainable Development Goals (SDGs) formulated by the United Nations, especially Goal 7 (ensuring access to affordable, reliable and sustainable modern energy for all) and Goal 13 (taking urgent action to address climate change and its impacts) can be achieved.

[0232] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, a first ball bearing BB1 and a second ball bearing BB2 are provided between the housing 20 and the bracket 60, but the present invention is not limited thereto, and a bush or a bearing also called a sliding bearing may be used instead of the first ball bearing BB1 and the second ball bearing BB2 (to reduce costs).

[0233] In addition, in the above-described embodiment, a case where a total of three planetary gears 50 are provided is shown, but the present invention is not limited thereto, and four or more planetary gears 50 may be provided. In addition, if there are two planetary gears 50 (an even number), they are arranged 180 degrees opposite to each other, and it is difficult to maintain the pinion 30 in a balanced manner. Therefore, it leads to an increase in operating noise or a decrease in transmission efficiency [%]. On the other hand, if there are five or more planetary gears 50, the assembly performance is reduced or it leads to an increase in size. Therefore, when used for purposes such as the above-described embodiment, the number of planetary gears 50 is ideally three (an odd number).

[0234] Furthermore, the assembly process of the planetary gear reduction mechanism 10 is only one example of several assembly processes, and other assembly processes can also be used for assembly. Fig.13 The process is performed at a stage prior to the "assembly of the housing body 21 and the ring member 22" shown in FIG. Fig.14 “Assembly of the pinion gear 30 and the play adjustment mechanism BA” shown in FIG.

[0235] In addition, as long as the present invention can be achieved, the material, shape, size, number, installation location, etc. of each component in the above-mentioned embodiment are arbitrary and are not limited to the above-mentioned embodiment.

Claims

1. A planetary gear reduction mechanism, comprising: A sun gear, disposed on the rotating shaft; An internal gear, disposed radially outward of the sun gear; a planetary gear disposed between the sun gear and the internal gear; and A planet carrier supports the planetary gears to rotate freely. The planetary gear reduction mechanism has: A first bearing is provided on one side of the sun gear in the axial direction of the rotating shaft and rotatably supports the rotating shaft; A second bearing is provided on the other side of the sun gear in the axial direction of the rotating shaft and rotatably supports the rotating shaft; a first bearing support portion, provided on the planetary carrier, and supporting the first bearing in a manner that the first bearing cannot move in the axial direction of the rotating shaft; and a second bearing support portion provided on the planetary carrier and supporting the second bearing so as to be movable in the axial direction of the rotating shaft; The first bearing and the second bearing are arranged so as not to be close to each other in the axial direction of the rotating shaft. The second bearing support portion is provided with a pressing member that presses the second bearing toward the side where the first bearing is provided.

2. The planetary gear reduction mechanism according to claim 1, wherein: The first bearing comprises a first inner ring and a first outer ring, The first inner ring is fixed to the rotating shaft, The first outer ring is supported by the first bearing support portion.

3. The planetary gear reduction mechanism according to claim 1, wherein: The second bearing comprises a second inner ring and a second outer ring, One axial side of the second inner ring is supported by a step portion provided on the rotating shaft. The other axial side of the second outer ring is supported by the pressing member.

4. The planetary gear reduction mechanism according to claim 1, wherein: The pressing member is screwed to the second bearing support portion.

5. The planetary gear reduction mechanism according to claim 1, wherein: The planetary gears are supported by ball bearings on both axial sides.

6. The planetary gear reduction mechanism according to claim 1, wherein: The sun gear has only one tooth that is spirally connected in the axial direction of the rotating shaft.

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