JP2020041680A - Differential decelerator - Google Patents

Abstract

To provide a differential decelerator capable of sufficiently securing lubrication performance relating to an eccentric portion at low costs.SOLUTION: A decelerator 1 includes an internal gear 20, an input shaft 4 disposed coaxially with the internal gear 20 while penetrated in the internal gear 20, and having a first eccentric portion 34 and a second eccentric portion 40 eccentric to an input central axis (central axis C0) as its central axis, a plurality of rollers 60, 62 disposed in a state that roller central axes as their central axes are in the same direction as the central axis C0 at the radial outer side of the first eccentric portion 34 and the second eccentric portion 40, and a first external gear 6A and a second external gear 6B disposed at a radial outer side of the rollers and inscribed in and engaged with the internal gear 20. The input shaft 4 has a first groove 36 and a second groove 42 adjacent to the first eccentric portion 34 and the second eccentric portion 40 in the direction of the input central axis, and both ends of each of the plurality of rollers 60, 62 are opposed to a first groove 36 and a second groove 42.SELECTED DRAWING: Figure 1

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal oscillating differential speed reducer having an external gear that rotates so as to mesh with an internal gear and oscillate.

2. Description of the Related Art As an eccentric oscillating gear device, there is known an eccentric oscillating gear device described in JP-A-2017-96312 (Patent Document 1).
In this gear device, a first eccentric body 21 for oscillatingly rotating the first external gear 11 and a second eccentric body 22 for oscillatingly rotating the second external gear 12 adjacent to the first external gear 11 are provided. An exterior crankshaft 14 is provided. An outer spline 70 extending in the axial direction is formed on the outer peripheral surface of the crankshaft 14, and a groove thereof forms an axial passage Ar for lubricant. Further, in the central cylindrical band 23 provided between the first eccentric body 21 and the second eccentric body 22, six radial passages Rr formed of through holes 25 are formed in the radial direction. . The radial passage Rr communicates with the axial passage Ar, and the lubricant is supplied to the first eccentric body 21 and the second eccentric body 22 through the axial passage Ar and the radial passage Rr.

Relatedly, as a seal structure of a speed reducer, one described in Japanese Utility Model Laid-Open No. 4-98860 (Patent Document 2) is known.
In this sealing structure, an O-ring 8 is provided between a cylindrical projection (inlay) 4 a of the bracket 4 disposed in an end of the frame 5 and an end of the gear case 2 fitted to the projection. The O-ring 8 includes a bottom surface of a groove 4C having a depth dimension C and a width dimension D provided around the outer surface of the projection 4a, a side surface 4b of the bracket, and a chamfered portion 2a formed at an end of the gear case 2. , Are compressed on three sides.

Further, as another related art, a planetary gear structure described in Japanese Patent Application Laid-Open No. 2003-65403 (Patent Document 3) is known.
In this planetary gear structure, the planetary gears 210A and 210B are attached to two eccentric bodies 218A and 218B formed on the input shaft 216 via bearings 220A and 220B. The planetary gears 210A and 210B mesh with an internal gear 270 integrated with the first and second casings 232 and 234. The first and second casings 232 and 234 support the output-side carrier 228A via the cross roller 230. The carrier 228B on the input side is connected to the carrier 228A by an inner pin (no symbol) for taking out the rotation of the planetary gears 210A, 210B, and a bolt 226. Planet gears 210A and 210B are arranged between carriers 228A and 228B.

Also related to this, a power transmission device described in International Publication WO 2006/85536 (Patent Document 4) is known.
In this power transmission device, eccentric bodies 122A and 122B are integrally formed on an input shaft 120 provided with a hollow portion 120H for passing wiring and the like. The diameter Dh of the hollow portion 120H is constant over the entire axial direction. External gears 126A, 126B are rotatably fitted to the eccentric bodies 122A, 122B via the eccentric body bearings 124A, 124B while meshing with the internal gear 130. An inner pin 134 for taking out their relative rotation is loosely fitted to the external gears 126A and 126B. On the output side of the external gears 126A and 126B, a first support flange 148 connected to the counterpart machine 190 is provided as an output shaft. A second support flange 149 is disposed on the input side of the external gears 126A and 126B. The first support flange 148 and the second support flange 149 are connected by a carrier pin 150. An oil seal 173A is arranged outside the input end of the input shaft 120, and an oil seal 173B is arranged outside the output end of the input shaft 120.

JP-A-2017-96312 Japanese Utility Model Publication No. 4-98860 JP-A-2003-65403 International Publication WO2006 / 85536

In the above-described eccentric oscillating gear device, when the lubrication performance is improved by increasing the supply amount of the lubricant to the first eccentric body 21 and the second eccentric body 22, more through holes are formed in the central cylindrical band 23. The formation of the holes 25 is required, and the processing is troublesome and the cost is increased accordingly.
Therefore, a main object of the present invention is to provide a differential reducer in which lubrication performance of an eccentric body (eccentric portion) is sufficiently ensured at low cost.

In the above-described seal structure of the speed reducer, since the O-ring 8 is pressed by the chamfered portion 2a, the radial thickness of the gear case 2 needs to be sufficiently ensured from the viewpoint of ensuring strength. If the thickness is insufficient, the pressing force against the O-ring 8 becomes insufficient, and the sealing becomes incomplete, which may cause grease leakage or the like. When the thickness is sufficiently ensured, the speed reducer is correspondingly large.
Therefore, a main object of the related invention is to provide a speed reducer that can be made compact while ensuring the sealing performance.

Further, in the above-described planetary gear structure, if the bolt 226 connecting the carriers 228A and 228B is loosened due to an excessive load or an impact, the carrier 228B may fall to the input side.
In addition, it is conceivable to fix the pair of carriers only by press-fitting the inner pin for downsizing, etc., but if the inner pin comes off due to an excessive load or impact, etc., the carrier on the input side comes off. there is a possibility.
Accordingly, a main object of another related invention is to provide a differential reducer in which a carrier on an input side is prevented from dropping off even when an excessive load or impact occurs.

Furthermore, in the above-described power transmission device, since the diameter Dh of the hollow portion 120H is constant over the entire axial direction, there is a limit in reducing the outer diameter of the output end of the input shaft 120, and the oil seal 173B There is a limit in reducing the peripheral speed of the output side end of the input shaft 120 that comes into contact with the oil seal 173B, and there is a limit in reducing the rotational loss of the input shaft 120 while maintaining the sealing performance of the oil seal 173B.
Therefore, a main object of still another related invention is to provide a differential gear reducer in which a rotation loss of an input shaft is reduced by making an inner diameter of an oil seal on an output side smaller.

The invention according to claim 1 is arranged such that the internal gear and the internal gear coaxially penetrate into the internal gear, and are eccentric with respect to the input central axis which is its own central axis. An input shaft having an eccentric portion, and a plurality of rollers arranged radially outside of the eccentric portion in a state where a roller central axis which is its own central axis is in the same direction as the input central axis; An external gear that is disposed radially outside of the rollers and is in contact with and meshes with the internal gear.The input shaft has a groove adjacent to the eccentric portion in the direction of the input central axis. And at least one of both ends of each of the plurality of rollers is disposed so as to face the groove.
The invention according to claim 2 is characterized in that, in the above invention, the length of the roller in the direction of the roller center axis is longer than the length of the eccentric portion in the direction of the input center axis. .
According to a third aspect of the present invention, in the above-mentioned invention, the grooves are formed on both sides of the eccentric portion.
According to a fourth aspect of the present invention, in the above invention, the groove is formed over the entire circumference of the input shaft.
According to a fifth aspect of the present invention, in the above-mentioned invention, the groove is coaxial with the eccentric portion.
According to a sixth aspect of the present invention, in the above invention, the groove is coaxial with the internal gear.
The invention according to claim 7 is characterized in that, in the invention described above, the input shaft is provided with a regulating portion that regulates movement of the plurality of rollers in the direction of the roller center axis. It is.
According to an eighth aspect of the present invention, in the above invention, the regulating portions are respectively arranged on both sides of the plurality of rollers on the roller center axis.

A related invention relates to a cylindrical first side surface perpendicular to the axial direction, a first spigot surface formed on the outer peripheral side, and an O-ring formed between the first side surface and the first spigot surface. A second case having a first case member having a groove, a second cylindrical side surface fitted with the first case member, the second side surface being perpendicular to the axial direction, and a second spigot surface formed on the inner peripheral side; A member, and an O-ring disposed in the O-ring groove, wherein the O-ring groove is axially recessed with respect to the first side surface and a bottom surface with respect to the first spigot surface. The O-ring has a side surface that is concave in the radial direction, and the O-ring is compressed by the bottom surface and the second side surface.
A related invention is characterized in that, in the above invention, the first case member has an internal tooth portion on an inner periphery, and the O-ring is arranged radially outward of the internal tooth portion. Is what you do.
In a related invention, in the above invention, a depth of the O-ring groove from the first side surface to the bottom surface is equal to or larger than a radius of the O-ring.
In a related invention, in the above invention, the second side surface is in contact with the first side surface.

Another related invention is a casing having an internal tooth portion on an inner periphery, a first carrier member rotatably supported in the casing via a bearing, and a second carrier member disposed in the casing. An external gear that is disposed between the first carrier member and the second carrier member, is in contact with and meshes with the internal gear portion, and has a plurality of through holes; A plurality of pin members which are inserted and integrally connect the first carrier member and the second carrier member, wherein the external gear in the second carrier member is provided on the inner surface of the casing. A protrusion facing inward from the other portion is formed on a portion facing the side surface opposite to the side.
Another related invention is characterized in that, in the above invention, the projection has an annular shape coaxial with an axis of the internal tooth portion.
Another related invention is characterized in that, in the above invention, the protrusion is disposed so as to face a radially inner part of the side surface of the second carrier member.
According to another related invention, in the above invention, the second carrier member has a plurality of pin holding holes respectively holding a plurality of the pin members, and the second carrier member is provided between the second carrier member and the protrusion. The distance is equal to or less than the length of the pin member in the pin holding hole.

Still another related invention is a casing having an inner tooth portion on an inner periphery, and a cylindrical shape, which is arranged coaxially with the inner tooth portion radially inward of the inner tooth portion, and has its own central axis. An input shaft having an eccentric portion that is eccentric with respect to the first shaft, a first inner surface portion having a first inner diameter, and a second inner surface portion having a second inner diameter larger than the first inner diameter; An external gear which is in contact with and meshes with a tooth portion, a ring-shaped first seal member which comes into contact with an end of the input shaft on the first inner surface side from outside in the radial direction to seal, and A ring-shaped second seal member that comes into contact with and seals the end on the second inner surface side from the outside in the radial direction, wherein the inner diameter of the second seal member is larger than the inner diameter of the first seal member. Is also small.
Still another related invention is characterized in that, in the above invention, the inner surface of the first inner surface portion is a polished surface, and the inner surface of the second inner surface portion is a turned surface. .
Still another related invention is the above-described invention, wherein the end of the input shaft on the first inner surface side protrudes from the casing, and the end of the input shaft on the second inner surface side is the casing. It is characterized by being retracted inside.

A main effect of the present invention is to provide a differential reducer in which lubrication performance of an eccentric body (eccentric portion) is sufficiently ensured at low cost.
The main effect of the related invention is to provide a speed reducer that can be made compact while ensuring the sealing performance.
A main effect of another related invention is to provide a differential speed reducer in which a carrier on an input side is prevented from dropping off even when an excessive load or impact occurs.
A further main effect of the related invention is to provide a differential reducer in which the inner diameter of the oil seal on the output side is reduced, thereby reducing the rotational loss of the input shaft.

FIG. 3 is a central longitudinal sectional view of the speed reducer according to the present invention. FIG. 2 is a partially enlarged view of an upper part of an O-ring and its vicinity in FIG. 1. It is a center longitudinal cross-sectional view of a speed reducer according to a modified example of the present invention.

  Hereinafter, embodiments of the present invention and modifications thereof will be described with reference to the drawings as appropriate. Note that the present invention is not limited to the following embodiments and modified examples.

FIG. 1 is a central longitudinal sectional view of a speed reducer 1 according to the present invention.
The reduction gear 1 is an internal-joint swing type differential reduction gear.
The reduction gear 1 has a cylindrical casing 2 whose axial direction is the direction of the central axis C0 in the left-right direction of the drawing, and a cylindrical input shaft 4 coaxially arranged with the casing 2 in a radially inward direction of the casing 2. A first external gear 6A and a second external gear 6B which are a plurality (two) of external gears disposed between the casing 2 and the input shaft 4; (2) A cylindrical output shaft 10 (first carrier member) disposed on the output side of the external gear 6B, and a ring-shaped output shaft 10 disposed on the input side of the first external gear 6A on the right side (input side) in the figure. A plurality of (eight) carrier carriers 12 (second carrier members) extending in the axial direction from the carrier carrier 12 to the output shaft 10 via the first external gear 6A and the second external gear 6B, respectively, and being arranged in the circumferential direction. And a pin 14 (pin member) provided.

The casing 2 includes a middle case 22 (first case member) integrally having an internal gear 20 on an inner surface, a disk-shaped case cover 24 disposed on an input side end surface of the middle case 22, and an output in the middle case 22. And an outer case 26 (second case member) disposed on the side end surface.
The middle case 22, the case cover 24, and the outer case 26 are connected by a plurality of bolts 28 that penetrate the middle case 22 from the case cover 24 side and are engaged with the outer case 26.

The input shaft 4 has a hollow cylindrical shape so as to pass wiring and the like.
The input shaft 4 is arranged such that the input end protrudes from the end of the casing 2 and the output end protrudes from the end of the casing 2 and the end of the output shaft 10. That is, the input end of the input shaft 4 is located closer to the input side than the end of the casing 2, and the output end of the input shaft 4 is located closer to the input side than the end of the output shaft 10. ing.
The first inner surface portion 29a, which is the inner surface portion of the input side portion 4a of the input shaft 4, is polished for centering, and the input side end of the input shaft 4 extends in the axial direction. A plurality of connection bolt holes 30 are provided, and the input side portion 4a is formed as a drive shaft spigot to which a drive shaft (not shown) can be connected.
The inner diameter (second inner diameter) of the second inner surface portion 29b, which is the inner surface portion of the output side portion 4b, is larger than the inner diameter (first inner diameter) of the first inner surface portion 29a, and is polished when the first inner surface portion 29a is polished. It's an escape. The second inner surface 29b is not polished, and the second inner surface 29b is a turned surface.

At the center of the outer surface of the input shaft 4, radially outward of the step 31 at the boundary between the input side portion 4 a (first inner surface portion 29 a) and the output side portion 4 b (second inner surface portion 29 b), An input-side shoulder portion 33 is provided, which protrudes radially outward from the input-side end outer surface portion 32 which is the outer surface of the side portion 4a. The top of the input-side shoulder 33 is formed around the central axis C0.
On the output side of the input side shoulder 33, a first eccentric part 34 having a cylindrical surface centered on the first eccentric axis C1 which is oriented in the same direction as the central axis C0 and is deviated from the central axis C0 is formed. Have been.
On both sides of the first eccentric part 34 in the axial direction, a first groove 36 is formed one round. Each first groove 36 is formed around the central axis C0, and is deepest at a position adjacent to the maximum eccentric portion of the first eccentric portion 34 and shallowest at a position adjacent to the minimum eccentric portion of the first eccentric portion 34. ing. The first groove 36 may be provided on any one side of the first eccentric part 34, may be provided at the center of the first eccentric part 34, or may be omitted. Further, at least one of the first grooves 36 may not be disposed (the depth may be eliminated) in the minimum eccentric portion of the first eccentric portion 34.
On the output side of the first groove 36 on the output side, a central shoulder 38 similar to the input side shoulder 33 is formed.

On the output side of the central shoulder 38, a second eccentric having a cylindrical surface centered on a second eccentric axis C2 eccentric with the same amount as the first eccentric axis C1 in a state in which the phase differs from the first eccentric axis C1 by 180 °. A part 40 is formed.
On both sides of the second eccentric part 40 in the axial direction, a second groove 42 is formed one round. Each second groove 42 is formed around the center axis C0, and is deepest at a position adjacent to the maximum eccentric portion of the second eccentric portion 40 and shallowest at a position adjacent to the minimum eccentric portion of the second eccentric portion 40. ing. The second groove 42 may be provided on any one side of the second eccentric part 40, may be provided at the center of the second eccentric part 40, or may be omitted. Further, at least one of the second grooves 42 may not be disposed (the depth may be eliminated) in the minimum eccentric portion of the second eccentric portion 40.
An output side shoulder 44 similar to the input side shoulder 33 is formed on the output side of the output side second groove 42.
The input-side shoulder 33, the central shoulder 38, and the output-side shoulder 44 are higher than the radial heights of the maximum eccentric portions of the first eccentric portion 34 and the second eccentric portion 40, and have a wall shape.
The first groove 36 serves as a polishing relief when polishing the first eccentric portion 34, and the second groove 42 serves as a polishing relief when polishing the second eccentric portion 40.

The outer surface of the input shaft 4 on the output side of the output side shoulder portion 44, except for the output side end portion, is an output side outer surface portion 46 formed similarly to the input side end outer surface portion 32.
The output side end outer surface 48, which is the outer surface of the output side end of the input shaft 4, is formed so that its outer diameter is smaller than the outer diameter of the output side outer surface 46.

A first ball bearing 50 that rotatably supports the input shaft 4 is disposed on the input side of the input shaft 4 adjacent to the input side shoulder 33. The first ball bearing 50 is sandwiched and held by a projection 52 formed to project radially inward on the inner surface of the center hole of the case cover 24 and the input side shoulder 33. The protrusion 52 presses the input side surface of the outer ring of the first ball bearing 50, and the input shoulder 33 presses the output side surface of the inner ring of the first ball bearing 50.
On the other hand, a second ball bearing 54 similar to the first ball bearing 50 is disposed at a portion adjacent to the output side of the output side shoulder portion 44. The second ball bearing 54 is held by a step 56 formed by enlarging the input side of the inner surface of the output shaft 10 from the output side, and the output side shoulder 44. The step 56 presses the outer ring (output side) of the second ball bearing 54, and the output shoulder 44 presses the inner ring (input side) of the first ball bearing 50.

In addition, radially outside the first eccentric portion 34 and each first groove 36, the first external gear 6 </ b> A is extended through a plurality of cylindrical rollers 60 extending in the axial direction and arranged in the circumferential direction. Are rotatably supported. A first needle bearing that supports the first external gear 6A is formed by combining all the rollers 60. The roller central axis, which is the central axis of each roller 60, faces in the same direction as the central axis C0, and the axial length of each roller 60 is longer than the axial length of the first eccentric portion 34. The movement of each roller 60 in the axial direction is regulated by the input-side shoulder 33 and the central shoulder 38 (regulator).
Similarly, on the radially outer side of the second eccentric portion 40 and each of the second grooves 42, a second external gear is provided via a plurality of cylindrical rollers 62 extending in the axial direction and arranged in the circumferential direction. 6B is rotatably supported. A second needle bearing that supports the second external gear 6B is formed by combining all the rollers 62. The roller central axis, which is the central axis of each roller 62, faces in the same direction as the central axis C0, and the axial length of each roller 62 is longer than the axial length of the second eccentric portion 40. The axial movement of each roller 62 is regulated by the central shoulder 38 and the output-side shoulder 44 (regulator).

A ring-shaped first seal member 66 that is in contact with the input-side end outer surface portion 32 of the input shaft 4 is attached to a portion of the case cover 24 on the inner side of the central hole on the input side with respect to the protrusion 52. The first seal member 66 is an elastic body (made of rubber), and seals between the case cover 24 and the input shaft 4 while allowing the rotation of the input shaft 4.
On the other hand, a ring-shaped second seal member 68 that is in contact with the output side end outer surface portion 48 of the input shaft 4 is attached to the output side portion of the inner surface of the central hole of the output shaft 10. The second seal member 68 is an elastic body (made of rubber), and seals between the output shaft 10 and the input shaft 4 while allowing the rotation of the input shaft 4.
The outer diameter of the output-side end outer surface portion 48 is smaller than the outer diameter of the input-side end outer surface portion 32, and the inner diameter of the second seal member 68 is smaller than the inner diameter of the first seal member 66.
The thickness of the output-side end outer surface portion 48 of the input shaft 4 is not more than half (1/2) the thickness of the adjacent output-side outer surface portion 46.

The first external gear 6A and the second external gear 6B each have a smaller number of teeth than the internal gear 20 of the middle case 22 and have the same number of teeth, and mesh with the internal gear 20 at the eccentric position. ing.
In the first external gear 6A, a plurality (eight) of circular through-holes 70A arranged in a concentric circle are formed at equal intervals in the circumferential direction. Similarly, a plurality (eight) of through-holes 70B are formed in the second external gear 6B. Then, one pin 14 is loosely inserted into the pair of through holes 70A and 70B. At the outer periphery of each pin 14, a cylindrical metal 72 is externally provided at a free insertion portion of the first external gear 6 </ b> A and the second external gear 6 </ b> B.
Each pin 14 inscribes the outer periphery of the corresponding metal 72 with the inner periphery of the through-holes 70A and 70B at phases different from each other by 180 °.
Each pin 14 is installed between the output shaft 10 and the carrier receiver 12. The input-side end of each pin 14 is pressed into a corresponding pin holding hole 74 provided in the carrier receiver 12, and the output-side end of each pin 14 is connected to a corresponding output shaft provided on the output shaft 10. It is pressed into the through hole 76. A pinning bolt 78 is inserted into the output end of each pin 14. The output side portion is larger in diameter than the input side portion of the output shaft through hole 76, and an output shaft through hole stepped portion 79 is formed at the boundary between these portions. The pin 14 is press-fitted, and the head of the pinning bolt 78 is arranged at the output side portion of the output shaft through-hole 76 so that the head can be hooked on the step portion 79 of the output shaft through-hole. The carrier receiver 12 is rotatably supported by the first ball bearing 50, and is rotatable integrally with the output shaft 10 via each pin 14.

A portion of the inner surface (output side surface) of the case cover 24 facing a side surface (a vertical surface on the input side) of the carrier receiver 12 opposite to the first external gear 6A includes a portion around the inner surface. A protruding portion 80 protruding further inward (output side) is formed.
The protrusion 80 has an annular shape coaxial with the central axis C0 (axial center) of the internal gear 20 (internal gear).
Further, the protrusion 80 is arranged on a radially inner portion of the inner surface of the case cover 24, and is arranged to face a radially inner portion of the carrier receiver 12. The protrusion 80 is adjacent to the first ball bearing 50 on a radially inner surface, and does not hinder the rotation of the outer ring of the first ball bearing 50 and the carrier receiver 12.
The distance D1 between the vertical surface on the input side of the carrier receiver 12 and the top (the surface on the output side) of the protrusion 80 is the length of the pin holding hole 74 of the carrier receiver 12, that is, the length of the pin 14 in the pin holding hole 74. Less than D2.

The outer case 26 has an output shaft via a plurality of columnar cross rollers 81 arranged on an imaginary circle centered on the center axis C0 in a state in which the center axis is alternately skewed on the inner side in the radial direction. 10 is rotatably supported around a central axis C0. The outer case 26 is an outer ring of a cross roller bearing related to the cross roller 81, and the output shaft 10 is an inner ring of the cross roller bearing. Note that, like a needle bearing, a set of cross rollers 81 may be regarded as constituting a bearing.
The outer case 26 holds a ring-shaped output shaft oil seal 82 that is in contact with the outer peripheral surface of the output shaft 10 on the inner surface at the output side portion of the inner surface.

  A casing input side O-ring 90 for sealing is interposed between the middle case 22 and the case cover 24 in the casing 2, and a casing for sealing is interposed between the case cover 24 and the outer case 26. The O-ring 92 on the output side of No. 2 is sandwiched.

  The case cover 24 has a case cover spigot 100 for fitting the middle case 22 so as to protrude cylindrically from the vertical surface on the output side to the output side. The casing input side O-ring 90 is provided with a case cover spigot. It is put in a case cover groove 102 formed so as to be depressed inward in the radial direction at the base of the outer surface in the radial direction in 100. A chamfered portion 104 is provided at a portion on the input side of the inner surface of the middle case 22 that faces the case cover groove 102. The casing input-side O-ring 90 is compressed by the bottom surface of the case cover groove 102, the input-side surface, and the chamfered portion 104.

The O-ring 92 is disposed in an O-ring groove 110 formed in the middle case 22 as shown in FIG. The O-ring 92 is arranged radially outward of the internal gear 20. A first side surface 112 perpendicular to the axial direction is formed on the radially outer side of the output side end of the middle case 22, and a first spigot 114 for fitting the outer case 26 is formed on the radially inner side. It is formed so as to project cylindrically to the output side with respect to one side surface 112. An O-ring groove 110 is formed between a first spigot surface 114 a, which is a radially outer surface of the first spigot 114, and the first side surface 112.
The O-ring groove 110 has a bottom surface portion 110b recessed axially toward the input side with respect to the first side surface 112, and a side surface portion 110s recessed radially inward with respect to the first spigot surface 114a. . The side surface 110s faces the bolt hole 116 of the middle case 22 through which the bolt 28 passes.
The depth D3 of the O-ring groove 110 from the first side surface 112 to the bottom surface 110b is larger than the radius D4 of the O-ring 92.
The outer case 26 has the input side end fitted to the middle case 22 by receiving the first spigot 114, and has a second side surface 120 perpendicular to the axial direction and opposed to the first side surface 112, and a radially inner side ( A second spigot surface 122 formed on the inner peripheral side) and opposed to the first spigot surface 114a. The radially inner portion of the second side surface 120 faces the bottom surface portion 110b of the O-ring groove 110 (excluding the portion that is concave in the radial direction by the side surface portion 110s).
The O-ring 92 is axially compressed by the bottom surface portion 110b of the O-ring groove 110 and a radially inner portion of the second side surface 120, and the side surface portion 110s does not contribute to the compression of the O-ring 92.

The casing 2 is hermetically sealed by the first seal member 66, the second seal member 68, the output shaft oil seal 82, the casing input side O-ring 90, and the O-ring 92.
Grease is applied or filled in the casing 2. Note that a lubricant other than grease may be used.

Next, an operation example of such a speed reducer 1 will be described.
When the input shaft 4 rotates by receiving a rotation input from the drive shaft, the first eccentric portion 34 and the second eccentric portion 40 perform eccentric movements respectively symmetrically, and the first external gear 6A and the second external gear 6B are moved. The eccentricity and the rotation are performed in a state of being in contact with the internal gear 20. For this reason, each of the through holes 70A and 70B also undergoes eccentricity and rotational movement. Since each of the through holes 70A and 70B is formed to have a larger diameter than the pin 14 including the metal 72, each of the metal 72 is formed with the through holes 70A and 70B. When the pin 14 is inscribed, the eccentric component moves relatively to absorb the eccentric component, and only the rotation component is extracted from each pin 14. Therefore, the output shaft 10 and the carrier receiver 12 rotate synchronously via the pins 14, and the output shaft 10 rotates in a state where the output shaft 10 is decelerated at a predetermined reduction ratio.

Next, the operation and effect of the speed reducer 1 will be described.
The speed reducer 1 is cylindrical and formed on a first side surface 112 perpendicular to the axial direction, a first spigot surface 114a formed on the outer peripheral side, and between the first side surface 112 and the first spigot surface 114a. A middle case 22 having an O-ring groove 110, a second side surface 120 which is cylindrical and fitted in the middle case 22 and is perpendicular to the axial direction, and a second spigot surface 122 formed on the inner peripheral side. An outer case 26 and an O-ring 92 disposed in the O-ring groove 110 are provided. The O-ring groove 110 has a bottom surface portion 110 b that is recessed in the axial direction with respect to the first side surface 112, and a first spigot surface. The O-ring 92 has a side surface portion 110 s that is concave in the radial direction with respect to 114 a, and the O-ring 92 is compressed by the bottom surface portion 110 b and the second side surface 120. Therefore, the O-ring 92 of the casing 2 is axially compressed by the bottom surface portion 110b of the O-ring groove 110 and the radially inner portion of the second side surface 120, and the O-ring 92 of the casing 2 (the middle case 22) is compressed. There is no need to secure the strength for compressing the O-ring 92 outside the ring 92, and the casing 2 (the middle case 22) can be made compact in the radial direction while maintaining the sealing performance. Become compact.
The middle case 22 has the internal gear 20 on the inner periphery, and the O-ring 92 is arranged radially outward of the internal gear 20. Therefore, the O-ring 92 overlaps the internal gear 20 in the radial direction, and the size of the speed reducer 1 in the axial direction decreases.
Further, the depth D3 of the O-ring groove 110 from the first side surface 112 to the bottom surface 110b is equal to or greater than the radius D4 of the O-ring 92. Therefore, when the outer case 26 is assembled to the middle case 22, more than half of the O-ring 92 enters the O-ring groove 110, making it difficult for the O-ring 92 to come off.
Still further, the second side surface 120 is in contact with the first side surface 112. Therefore, the end face on the input side of the outer case 26 is flat and can be formed simply, and the crushing allowance of the O-ring 92 can be managed only by the depth D3 of the O-ring groove 110.
Note that these configurations can also be applied to reduction gears other than the internal swing type differential reduction gear.

In addition, the speed reducer 1 is arranged so as to penetrate into the internal gear 20 and the internal gear 20 coaxially with the internal gear 20, and the input central axis (central axis C0) which is its own central axis. The input shaft 4 having the first eccentric portion 34 and the second eccentric portion 40 which are eccentric with respect to the input shaft 4 and the roller which is the central axis of the input shaft 4 on the radially outer side of the first eccentric portion 34 and the second eccentric portion 40 A plurality of rollers 60, 62 arranged in a state where the central axis is in the same direction as the central axis C0, and a first outer member arranged radially outside of the plurality of rollers 60, 62 and in contact with and meshing with the internal gear 20. The input shaft 4 includes a first groove 36 and a second groove adjacent to the first eccentric portion 34 and the second eccentric portion 40 in the direction of the input central axis. Each of the plurality of rollers 60, 62 has a first groove 36 and a second groove 42, respectively. They are arranged to face each other. Therefore, the rollers 60 and 62 are directly lubricated by the grease supplied to the first groove 36 and the second groove 42, and the lubrication performance of the speed reducer 1 is improved.
The length of the rollers 60 and 62 in the direction of the roller center axis is larger than the length of the first eccentric portion 34 and the second eccentric portion 40 in the direction of the center axis (the first eccentric axis C1 and the second eccentric axis C2). long. Therefore, the portions of the rollers 60 and 62 facing the first groove 36 and the second groove 42 are increased, and the lubrication performance of the speed reducer 1 is improved.
Further, the first groove 36 and the second groove 42 are formed on both sides of the first eccentric portion 34 and the second eccentric portion 40, respectively. Therefore, the integrity of each of the first eccentric portion 34 and the second eccentric portion 40 is ensured, and the lubrication performance of the reduction gear 1 is improved.
Further, the first groove 36 and the second groove 42 are formed over the entire circumference of the input shaft 4. Therefore, the first groove 36 and the second groove 42 face the rollers 60 and 62 so as to be able to supply grease over the entire circumference, and the lubrication performance of the speed reducer 1 is improved.
In addition, the first groove 36 and the second groove 42 are coaxial with the internal gear 20 (formed to have the same central axis as the central axis C0). Therefore, the first groove 36 and the second groove 42 can be turned simultaneously with portions of the input shaft 4 other than the first eccentric portion 34 and the second eccentric portion 40.
The input shaft 4 is provided with an input shoulder 33, a central shoulder 38, and an output shoulder 44 for restricting the movement of the plurality of rollers 60, 62 in the direction of the roller center axis. Therefore, the positions of the rollers 60 and 62 are stabilized by the input side shoulder 33, the center shoulder 38, and the output side shoulder 44, and the input side shoulder 33, the center shoulder 38, and the output side shoulder 44 are provided. The rollers 60 and 62 are sufficiently lubricated by the first groove 36 and the second groove 42.
Further, the input-side shoulder 33, the center shoulder 38, and the output-side shoulder 44 are respectively disposed on both sides of the roller central axis of the plurality of rollers 60, 62. Accordingly, the positions of the rollers 60 and 62 are more stable, and the rollers 60 and 62 are sufficiently lubricated even if the input side shoulder 33, the central shoulder 38, and the output side shoulder 44 are provided on both sides.

In addition, the reduction gear 1 is disposed in the casing 2, the output shaft 10 rotatably supported via the respective cross rollers 81 in the casing 2, and the casing 2 having the internal gear 20 on the inner periphery. The first external gear 6A, which is disposed between the carrier receiver 12 and the output shaft 10 and the carrier receiver 12, is in contact with and meshes with the internal gear 20, and has a plurality of through holes 70A, 70B. A second external gear 6B and a plurality of pins 14 which are loosely inserted into the through holes 70A and 70B, respectively, and integrally connect the output shaft 10 and the carrier receiver 12 are provided. A portion of the carrier receiver 12 that faces the side surface opposite to the first external gear 6A is formed with a protrusion 80 that protrudes inward from other portions. Therefore, even if the carrier receiver 12 is detached from the pin 14 due to an impact or the like and tries to fall off, the protrusion 80 of the casing 2 facing the carrier receiver 12 contacts the carrier receiver 12 to prevent the carrier receiver 12 from falling off, and the carrier receiver 12 and the internal structure Failure due to falling off is prevented.
The projection 80 has an annular shape that is coaxial with the axis of the internal gear 20 (center axis C0). Therefore, the carrier receiver 12 can rotate smoothly even in a state where the carrier receiver 12 is in contact with the protrusion 80.
Further, the protrusion 80 is arranged to face a radially inner portion of the side surface of the carrier receiver 12. Therefore, when the carrier receiver 12 rotates while being in contact with the protrusion 80, the carrier receiver 12 comes into contact with a lower peripheral speed, and the contact resistance between the carrier receiver 12 and the protrusion 80 is suppressed, and these are protected. You.
Further, the carrier receiver 12 has a plurality of pin holding holes 74 for respectively holding the plurality of pins 14, and the distance D1 between the carrier receiver 12 and the protrusion 80 is determined by the pin holding hole 74 of the pin 14. Within the length D2. Therefore, the carrier receiver 12 comes into contact with the protrusion 80 before completely disengaging from the pin 14 and is protected from a failure due to dropping.

In addition, the reduction gear 1 has a casing 2 having an internal gear 20 on the inner periphery thereof and a cylindrical shape, and is disposed coaxially with the internal gear 20 (central axis C0) radially inward of the internal gear 20. The first eccentric portion 34 and the second eccentric portion 40 which are eccentric with respect to the central axis thereof, the first inner surface portion 29a having a first inner diameter, and the second inner surface having a second inner diameter larger than the first inner diameter An input shaft 4 having a portion 29b, a first external gear 6A, a second external gear 6B, which is provided on the first eccentric portion 34 and the second eccentric portion 40 and is in contact with and meshes with the internal gear 20; A ring-shaped first seal member 66 that contacts the end of the shaft 4 on the side of the first inner surface portion 29a from the outside in the radial direction and seals the end of the input shaft 4 on the side of the second inner surface portion 29b on the side of the radial direction. And a ring-shaped second seal member 68 that contacts and seals from the other side. The inner diameter of the seal member 68 is smaller than the inner diameter of the first seal member 66. Therefore, the end on the side of the first inner surface portion 29a having a larger thickness is easily formed into an inlay for sufficiently connecting the drive shaft, and the end on the side of the second inner surface portion 29b on the opposite side is easily reduced in thickness. The inner diameter of the second seal member 68 that contacts the end on the side of the second inner surface portion 29b is easily reduced. In addition, the peripheral speed of the end on the side of the second inner surface portion 29b that comes into contact with the second seal member 68 is reduced by the reduction of the inner diameter, and the loss of the rotational motion of the input shaft 4 due to the contact of the second seal member 68 is suppressed. Is done.
The inner surface of the first inner surface portion 29a is a polished surface, and the inner surface of the second inner surface portion 29b is a turned surface. Therefore, the end of the first inner surface portion 29a is easily used as a drive shaft connecting spigot. Further, the second inner surface portion 29b serves as a polishing escape at the time of polishing the first inner surface portion 29a.
Further, an end of the input shaft 4 on the first inner surface 29a side protrudes from the casing 2, and an end of the input shaft 4 on the second inner surface 29b side is retracted inward of the casing 2. Therefore, the end on the first inner surface portion 29a side is easily used as a drive shaft connecting spigot. Further, the use of the end on the second inner surface portion 29b side as a drive shaft connecting spigot is not recommended, and it is easy to understand that the end on the first inner surface portion 29a side is a drive shaft connecting spigot.

Finally, further modifications of the speed reducer 1 will be described.
As shown in FIG. 3 relating to the speed reducer 201 in which a part of the speed reducer 1 has been changed (the same reference numerals are given to members or portions that are the same as those of the speed reducer 1), a first groove in the input shaft 204 is provided. 236 is formed so as to be coaxial with the first eccentric axis C1 of the first eccentric part 34, and the second groove 242 is formed so as to be coaxial with the second eccentric axis C2 of the second eccentric part 40. ing. The first groove 236 has the same depth at the maximum eccentric portion and the minimum eccentric portion of the first eccentric portion 34, and the second groove 242 has the same depth at the maximum eccentric portion and the minimum eccentric portion of the first eccentric portion 34. It has a great depth.
Thus, the first groove 236 and the second groove 242 are formed so as to be coaxial with the first eccentric part 34 and the second eccentric part 40. Therefore, the first groove 236 and the second groove 242 for lubrication can be easily processed simultaneously with the first eccentric portion 34 and the second eccentric portion 40.

At least one of the number of the first external gear 6A and the second external gear 6B, the number of the first eccentric portions 34 and the second eccentric portions 40, and the eccentric angle may be increased or decreased.
At least one of the number and type of the various bearings can be variously changed, for example, by increasing or decreasing the number of the first ball bearings 50 and the second ball bearings 54, or by using the rollers 60 and 62 (needle bearings) as ball bearings. is there.
The configuration of various members may be variously changed, such as the case 22 being integrated with the case cover 24 and the pins 14 being bolted to the carrier receiver 12.

  1. Reducer (differential reducer), 2. Casing, 4 ... input shaft, 6A ... 1st external gear (external gear), 6B ... 2nd external gear (external gear) ······ Output shaft (first carrier member), 12 ··· Carrier receiver (second carrier member), 14 ··· Pin (pin member), 20 ··· Internal gear (internal gear), 22 ··· Case (first case member), 26... Outer case (second case member), 29a... First inner surface portion, 29b... Second inner surface portion, 33... Input side shoulder (restriction portion), 34. · 1st eccentric part, 36 · · · first groove (groove), 38 · · · central shoulder part (restriction part), 40 · · · second eccentric part, 42 · · · second groove (groove), 44 · · · output side Shoulder (regulator), 60, 62, roller, 66, first seal member, 68, second seal member, 70A, 70B, through hole, 72, pin holding hole, 80 · Projection, 81 ··· Cross roller (bearing), 92 ··· O-ring, 110 ··· O-ring groove, 110b ··· Bottom, 110s ··· Side, 112 ··· First side, 114a ··· First Inlay surface, 120... Second side surface, 122.

Claims (8)

Internal gear,
An input shaft that is disposed coaxially with the internal gear and penetrates into the internal gear, and has an eccentric portion that is eccentric with respect to an input central axis that is its own central axis;
On the radially outer side of the eccentric portion, a plurality of rollers arranged in a state where the roller central axis, which is its own central axis, is in the same direction as the input central axis,
An external gear that is arranged radially outside of the plurality of rollers and inscribes and meshes with the internal gear;
With
The input shaft has a groove adjacent to the eccentric portion in a direction of the input central axis,
A differential reduction gear, wherein at least one of both ends of each of the plurality of rollers is arranged to face the groove. The differential reduction gear according to claim 1, wherein a length of the roller in a direction of the roller center axis is longer than a length of the eccentric portion in a direction of the input center axis. The differential reduction gear according to claim 1 or 2, wherein the grooves are formed on both sides of the eccentric portion, respectively. 4. The differential reduction gear according to claim 1, wherein the groove is formed over the entire circumference of the input shaft. The differential reduction gear according to claim 4, wherein the groove is coaxial with the eccentric part. The differential gear according to claim 4, wherein the groove is coaxial with the internal gear. The difference according to any one of claims 1 to 6, wherein the input shaft is provided with a restricting portion that restricts the plurality of rollers from moving in the direction of the roller center axis. Dynamic reducer. The differential reduction gear according to claim 7, wherein the restricting portions are arranged on both sides of the plurality of rollers on the roller center axis, respectively.

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