Gear reducer and method for assembling the gear reducer

Abstract

To stabilize the operation of the main bearing and sealing member in the gearbox. [Solution] The gearbox 10 includes a case 40, a carrier 20 at least partially disposed within the case 40, a main bearing 30 disposed between the case 40 and the carrier 20, and a sealing member 50 that seals the space between the carrier 20 and the case 40. At least one of the carrier 20 and the case 40 includes a body portion 20M or 40M and a flange portion 20F or 40F. The main bearing 30 is pressed axially DA between the body portion 20M of the carrier 20 and the case 40. The sealing member 50 is pressed axially DA between the flange portion 20F of the carrier 20 and the case 40. Alternatively, the main bearing 30 is pressed axially DA between the body portion 40M of the case 40 and the carrier 20. The sealing member 50 is pressed axially DA between the flange portion 40F of the case 40 and the carrier 20.

Description

Technical Field

[0001] The present invention relates to a speed reducer and a method for assembling the speed reducer.

Background Art

[0002] For example, as disclosed in Patent Document 1, a speed reducer including a case, a carrier at least partially disposed within the case, a main bearing disposed between the case and the carrier, and a seal member for sealing between the carrier and the case is known. In the speed reducer, one of the carrier and the case rotates relative to the other about a rotation axis. The main bearing and the seal member are pushed in an axial direction parallel to the rotation axis between the carrier and the case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The pressure required for the proper operation of the main bearing is different from the pressure required for the proper operation of the seal member. However, in the carrier of Patent Document 1, the portion pressing the main bearing and the portion pressing the seal member move relative to the case in联动. In the case of Patent Document 1, the portion pressing the main bearing and the portion pressing the seal member move relative to the carrier in联动. In the speed reducer of Patent Document 1, the axial pressure on the main bearing and the axial pressure on the seal member cannot be adjusted separately. In the speed reducer of Patent Document 1, it is difficult to achieve stable operation of both the main bearing and the seal member. The present invention aims to achieve stable operation of the main bearing and the seal member in a speed reducer.

Means for Solving the Problems

[0005] It should be noted that the "联动" in the original text seems to be a misspelling. It might be "联动" which is not a common term in this context. I translated it as "联动" as it is in the original text. If there is a correct term, it should be adjusted accordingly.A gear reducer according to one embodiment of the present invention is Career and, The main bearing held on the carrier, The case held on the main bearing, A sealing member that seals the space between the carrier and the case is provided, One of the carrier and the case rotates relative to the other of the carrier and the case about a rotation axis. The aforementioned one member includes a main body and a flange connected to the main body, The main bearing is pressed between the main body and the other member in an axial direction parallel to the axis of rotation. The sealing member is pressed in the axial direction between the flange portion and the other member.

[0006] A method for assembling a gearbox according to one embodiment of the present invention is: A carrier including a carrier body and a carrier flange connected to the carrier body, The main bearing held on the carrier, The case is held on the main bearing and includes a case body and a case flange connected to the case body, A method for assembling a speed reducer comprising a sealing member that seals the space between the carrier and the case, A step of pressing the main bearing which is positioned between the carrier body and the case body, The process of connecting the case flange to the case body, The steps include connecting the carrier flange to the carrier body, The process includes the step of pressing the sealing member positioned between the carrier flange and the case flange. [Effects of the Invention]

[0007] According to the present invention, the operation of the main bearing and sealing member in the gearbox can be stabilized. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a diagram illustrating one embodiment, and is a cross-sectional view of a speed reducer. [Figure 2] Figure 2 is a cross-sectional view of the gearbox in Figure 1 along the line II-II. [Figure 3] Figure 3 is an enlarged view of section A in Figure 1. [Figure 4] Figure 4 is a diagram illustrating a method for adjusting the pressure on the sealing member of the carrier flange. [Figure 5] Figure 5 is a diagram illustrating a method for adjusting the pressure on the sealing member of the case flange. [Modes for carrying out the invention]

[0009] One embodiment of the present invention relates to the following [1] to [7].

[0010] [1] Case and, A carrier, at least partially, is located within the aforementioned case. A main bearing is positioned between the case and the carrier, A sealing member that seals the space between the carrier and the case is provided, One of the carrier and the case rotates relative to the other of the carrier and the case about a rotation axis. The aforementioned one member includes a main body and a flange connected to the main body, The main bearing is pressed between the main body and the other member in an axial direction parallel to the axis of rotation. The sealing member is a reduction gear that is pressed in the axial direction between the flange portion and the other member.

[0011] [2] The other member includes a second main body and a second flange connected to the second main body, The main bearing is pressed in the axial direction between the main body and the second main body. The seal member is pressed in the axial direction between the flange portion and the second flange portion, and is a speed reducer of [1].

[0012] [3] The main bearing includes an inner ring, an outer ring, and a plurality of rolling elements disposed between the inner ring and the outer ring. The seal member overlaps the inner ring in the axial direction and is a speed reducer of [1] or [2].

[0013] [4] The connection surface between the flange portion and the main body portion is located on the same side as the seal member in the axial direction with respect to the main bearing, and is a speed reducer of any one of [1] to [3].

[0014] [5] The one member includes a connection portion connecting the main body portion and the flange portion. The connection portion is located on the inner side in the radial direction orthogonal to the rotation axis with respect to the seal member, and is a speed reducer of any one of [1] to [4].

[0015] [6] The flange portion includes a restricting portion that restricts the axial movement of the seal member, and is a speed reducer of any one of [1] to [5].

[0016] [7] A speed reducer assembly method including a case main body and a case including a case flange connected to the case main body, A carrier disposed at least partially within the case, the carrier including a carrier main body and a carrier flange connected to the carrier main body, A main bearing disposed between the case and the carrier, And a seal member that seals between the carrier and the case, the method comprising: Pressing the main bearing disposed between the carrier main body and the case main body; Connecting the case flange to the case main body and connecting the carrier flange to the carrier main body; Pressing the seal member disposed between the carrier flange and the case flange.

[0017] An embodiment of the present invention will be described with reference to the drawings. For ease of illustration and understanding, the dimensional ratios in the drawings may be changed from the dimensional ratios of the actual object.

[0018] The terms used to specify shapes, geometric conditions such as "parallel" and "orthogonal," and values ​​of lengths and angles are not interpreted strictly, but rather within a range that allows for the expectation of similar functionality.

[0019] Figures 1 to 5 are diagrams illustrating one embodiment. Figure 1 is a cross-sectional view of the reduction gear 10. The reduction gear 10 reduces the rotational motion from the input shaft and outputs it. The reduction gear 10 may be connected to a motor. The rotational motion input to the reduction gear 10 may be supplied from the motor.

[0020] The gearbox 10 in Figure 1 is an eccentric oscillating gearbox, as described below. The gearbox 10 is not limited to the illustrated example and may be a planetary gear type gearbox. The gearbox 10 includes a carrier 20, a main bearing 30, a case 40, and a sealing member 50. The carrier 20 is at least partially located within the case 40. One member of the carrier 20 and the case 40 rotates relative to the other member of the carrier 20 and the case 40 about the rotation axis RA via the main bearing 30. The sealing member 50 seals the space between the carrier 20 and the case 40.

[0021] In the gearbox 10 shown in Figure 1, one of the carrier 20 and the case 40 may be fixed. The other of the carrier 20 and the case 40 may rotate around the rotation axis RA relative to the fixed member. For example, in the gearbox 10, the case 40 may rotate relative to the fixed carrier 20. As another example, in the gearbox 10, the carrier 20 may rotate relative to the fixed case 40.

[0022] In the gearbox 10 of Figure 1, the main bearing 30 is held on the carrier 20. The case 40 is held on the main bearing 30. In the gearbox 10, when one component is held on another component, the component is held on the outside in the radial direction DR perpendicular to the rotation axis RA relative to the other component. The outside in the radial direction DR is the direction away from the rotation axis RA in the radial direction DR. The inside in the radial direction DR is the direction approaching the rotation axis RA in the radial direction DR.

[0023] The reduction gear 10 in Figure 1 includes a crankshaft 60 and an external gear 70. The crankshaft 60 is supported by the case 40 so that it can rotate relative to the case 40 about the rotation axis RAC. The external gear 70 is driven by the rotation of the crankshaft 60 relative to the case 40. In the illustrated reduction gear 10, the carrier 20 rotates relative to the case 40 about the rotation axis RA by the driven external gear 70. In the reduction gear 10, the rotation of the carrier 20 relative to the case 40 is output as rotational motion. Therefore, the illustrated carrier 20 is the output shaft of the reduction gear 10. In addition, the case 40 may be the output shaft of the reduction gear 10 instead of the carrier 20.

[0024] The carrier 20 in Figure 1 includes a carrier body 21 and a carrier flange 22 connected to the carrier body 21 in the axial direction DA. The carrier body 21 may also be referred to as the main body portion 20M of the carrier 20. The carrier flange 22 may also be referred to as the flange portion 20F of the carrier 20. The axial direction DA is parallel to the rotation axis RA described above.

[0025] In the carrier 20 shown in Figure 1, the carrier body 21 and the carrier flange 22 are connected to each other by bolts B1. The carrier body 21 and the carrier flange 22, connected by bolts B1, are restricted from moving relative to each other. The carrier body 21 and the carrier flange 22 may also be connected by a plurality of bolts B1 arranged at intervals in the circumferential direction DC. The bolts B1 may also be referred to as the connection portion 20T of the carrier 20. The connection portion 20T is a member that connects the carrier body 21 and the carrier flange 22. Note that the circumferential direction DC is the circumferential direction centered on the rotation axis RA.

[0026] The bolt B1 (connecting portion 20T) in Figure 1 is located inside the radial direction DR relative to the sealing member 50. According to the illustrated reduction gear 10, the outward protrusion of the radial direction DR in the portion where the connecting portion 20T is located can be suppressed, and the increase in the radial direction DR of the reduction gear 10 can be suppressed.

[0027] In Figures 1, 3 to 5, the axial direction DA is indicated by an arrow. In each figure, the tip of the arrow indicating the axial direction DA is the first side of the axial direction DA. The base of the arrow indicating the axial direction DA is the second side of the axial direction DA.

[0028] The case 40 in Figure 1 includes a case body 41 and a case flange 42 connected to the case body 41 in the axial direction DA. The case body 41 may also be referred to as the main body portion 40M of the case 40. The case flange 42 may also be referred to as the flange portion 40F of the case 40. In the case 40 of Figure 1, the case body 41 and the case flange 42 are connected to each other by bolts B2 and nuts N. The case body 41 and the case flange 42 connected by bolts B2 and nuts N are restricted from moving relative to each other. The case body 41 and the case flange 42 may be connected by a plurality of bolts B2 arranged at intervals in the circumferential direction DC. The bolts B2 and nuts N may also be referred to as the connection portion 40T of the case 40. The connection portion 40T is a member that connects the case body 41 and the case flange 42.

[0029] When the main body 20M of carrier 20 and the main body 40M of case 40 are listed together, the main body 20M of carrier 20 may be written as the first main body 20M or as [another term]. The main body 40M of case 40 may be written as the second main body 40M. Similarly, when the flange portion 20F of carrier 20 and the flange portion 40F of case 40 are listed together, the flange portion 20F of carrier 20 may be written as the first flange portion 20F. The flange portion 40F of case 40 may be written as the second flange portion 40F.

[0030] In the reduction gear 10 shown in Figure 1, the reduction gear body 10A is composed of a carrier body 21, a case body 41, a main bearing 30, a crankshaft 60, an external gear 70, and a spacer 80, which will be described later. In the illustrated reduction gear 10, the reduction gear cover 10B is composed of a carrier flange 22, a case flange 42, and a sealing member 50. The reduction gear cover 10B may also include a spacer 90, which will be described later with reference to Figure 5. The reduction gear 10 is composed of the reduction gear body 10A and the reduction gear cover 10B.

[0031] In the gearbox 10 shown in Figure 1, a gap G is provided between the carrier 20 and the case 40. The carrier 20 is at least partially positioned within the case 40, with a gap G between it and the case 40. The gap G in Figure 1 is provided between the carrier flange 22 and the case flange 42. The gap G opens in the axial direction DA. The gap G is located radially outward from the seal member 50 in the radial direction DR. The gap G in Figure 1 includes a portion extending in the axial direction DA and a portion extending in the radial direction DR.

[0032] The carrier 20 in Figure 3 includes a first carrier surface 201 and a second carrier surface 202 on the carrier body 21, which are separated from each other in the axial direction DA. Each of the first carrier surface 201 and the second carrier surface 202 is a circumferential surface facing the axial direction DA. The first carrier surface 201 and the second carrier surface 202 are separated by a distance LA in the axial direction DA. The illustrated carrier 20 is connected to the first main bearing 31 at the first carrier surface 201.

[0033] The carrier 20 in Figure 3 includes a third carrier surface 203 and a fourth carrier surface 204 in the carrier body 21, which are separated from each other in the axial direction DA. Each of the third carrier surface 203 and the fourth carrier surface 204 is a circumferential surface facing the radial direction DR. The third carrier surface 203 and the fourth carrier surface 204 are separated by a distance LR in the radial direction DR. The carrier 20 is connected to the main bearing 30 from the inside of the radial direction DR at the third carrier surface 203. The carrier 20 is connected to the main bearing 30 from the outside of the radial direction DR at the fourth carrier surface 204.

[0034] The carrier body 21 in Figure 1 includes a carrier base 23 and a carrier plate 24 connected to the carrier base 23 in the axial direction DA. The carrier plate 24 is connected to the carrier base 23 from the side opposite to the carrier flange 22 in the axial direction DA. The carrier base 23 is located between the carrier flange 22 and the carrier plate 24 in the axial direction DA. The illustrated carrier base 23 and carrier plate 24 are restricted from moving relative to each other by pins P. The carrier base 23 and carrier plate 24 may also be restricted from moving relative to each other by a plurality of pins P arranged in the circumferential direction DC. Contrary to the illustration, the carrier base 23 and carrier plate 24 may also be restricted from moving relative to each other by various fastening means such as bolts.

[0035] The carrier body 21 in Figure 1 includes a projection 25 that protrudes outward in the radial direction DR. The outer diameter of the carrier body 21 at the projection 25 is larger than the outer diameter of the carrier body 21 in the parts other than the projection 25. The illustrated carrier body 21 includes two projections 25 that are separated from each other. One of the two projections 25 is located on the carrier base 23. The projection 25 located on the carrier base 23 constitutes the first carrier surface 201. The other projection 25 is located on the carrier plate 24. The projection 25 located on the carrier plate 24 constitutes the second carrier surface 202. In the reduction gear 10 of Figure 1, the main bearing 30 is located between the two projections 25 in the axial direction DA.

[0036] In the carrier body 21 shown in Figure 1, one member of the carrier base 23 and the carrier plate 24 is pushed axially DA toward the other member of the carrier base 23 and the carrier plate 24 by a pin P. As the carrier base 23 and the carrier plate 24 are pushed toward each other by the pin P, the first carrier surface 201 and the second carrier surface 202 of the illustrated carrier body 21 are pushed toward each other axially DA. As a result, the illustrated carrier body 21 pushes the main bearing 30 axially DA.

[0037] In the carrier body 21 shown in Figure 1, the carrier base 23 is provided with a first through-hole 26a that penetrates the carrier base 23 in the axial direction DA. The carrier plate 24 is provided with a second through-hole 26b that penetrates the carrier plate 24 in the axial direction DA. The first through-hole 26a and the second through-hole 26b overlap in the axial direction DA.

[0038] First bearings 11 are positioned in the first through-hole 26a and the second through-hole 26b in Figure 1, respectively. The reduction gear 10 includes the first bearing 11 positioned in the first through-hole 26a and the first bearing 11 positioned in the second through-hole 26b. The crankshaft 60 is held in the carrier body 21 via the first bearings 11. As a result, the crankshaft 60 held in the carrier body 21 is rotatable about the rotation axis RAC relative to the carrier body 21. The rotation axis RAC in Figure 1 extends parallel to the axial direction DA.

[0039] The carrier base 23 in Figure 1 includes a base plate portion 230, a first projection 231, and a second projection 232. The first projection 231 protrudes from the base plate portion 230 to one side in the axial direction DA. The second projection 232 protrudes from the base plate portion 230 to the other side in the axial direction DA. The base plate portion 230 in Figure 1 includes a portion located between the first projection 231 and the second projection 232 in the axial direction DA. In the carrier base 23 of Figure 1, the base plate portion 230, the first projection 231, and the second projection 232 are integrally formed.

[0040] The base plate portion 230 in Figure 1 is a disc-shaped member. The carrier base 23 includes the aforementioned protrusion 25 in the base plate portion 230. Therefore, the carrier base 23 constitutes the first carrier surface 201 of the carrier 20 in the base plate portion 230. The carrier base 23 constitutes the third carrier surface 203 of the carrier 20 in the base plate portion 230.

[0041] The carrier base 23 in Figures 1 and 2 includes a plurality of first protrusions 231. In the carrier base 23, the plurality of first protrusions 231 project from the base plate portion 230 toward the second side in the axial direction DA. As shown in Figure 1, when the carrier base 23 and the carrier plate 24 are connected to each other, the first protrusions 231 are located between the carrier plate 24 and the base plate portion 230 in the axial direction DA. Figure 2 shows three first protrusions 231 arranged at intervals in the circumferential direction DC. Each of the three first protrusions 231 is provided with a hole SH2 for accommodating the aforementioned pin P. The hole SH2 opens toward the carrier plate 24 in the axial direction DA.

[0042] In the carrier base 23 of Figure 1, the second projection 232 constitutes the connection surface 200 between the carrier body 21 and the carrier flange 22. The connection surface 200 is a circumferential surface perpendicular to the axial direction DA. In the carrier 20 of Figures 1 and 3, the connection surface 200 is located first on the axial direction DA relative to the main bearing 30.

[0043] The carrier flange 22 in Figure 1 is a disc-shaped member having a first surface 221 and a second surface 222. The first surface 221 and the second surface 222 face each other in the axial direction DA. The carrier flange 22 is connected to the carrier body 21 in the axial direction DA at the first surface 221. The second surface 222 is further away from the case 40 in the axial direction DA than the first surface 221. The head of the bolt B1 that connects the carrier body 21 and the carrier flange 22 is connected to the second surface 222. As shown in Figure 3, the first surface 221 and the second surface 222 are separated by a distance LB in the axial direction DA.

[0044] The carrier flange 22 in Figures 1 and 3 includes a circumferential recess 27 for at least partially accommodating the sealing member 50. The recess 27 opens axially DA toward the carrier body 21. The radial dimension DR of the illustrated recess 27 gradually decreases as it moves away from the carrier body 21 axially DA. In other words, the radial dimension DR of the recess 27 gradually decreases as the recess 27 approaches the second surface 222 in axial DA.

[0045] The carrier flange 22 in Figures 1 and 3 includes a pressing surface 28 in the recess 27 that presses against the sealing member 50 from the outside in the radial direction DR. The illustrated pressing surface 28 is inclined with respect to the axial direction DA. In the illustrated carrier flange 22, the distance between the inclined pressing surface 28 and the rotation axis RA gradually decreases as the carrier flange 22 moves away from the carrier body 21 in the axial direction DA.

[0046] The carrier flange 22 in Figure 3 includes a restricting portion 29 that restricts the movement of the sealing member 50 in the axial direction DA. The restricting portion 29 is located in the axial direction DA between the second surface 222 of the carrier flange 22 and the contact position between the carrier flange 22 and the sealing member 50. The carrier flange 22 protrudes radially inward from the pressing surface 28 at the restricting portion 29.

[0047] The case body 41 in Figure 1 is provided with a first hole 43 that penetrates the case body 41 in the axial direction DA. The first hole 43 is open at both ends of the case flange 42 in the axial direction DA. The case flange 42 forms a space for accommodating the carrier 20, main bearing 30, crankshaft 60, and external gear 70, at least partially.

[0048] As shown in Figure 1, the case body 41 may be provided with a plurality of second holes 44 arranged in the circumferential direction DC. Each of the plurality of second holes 44 is located radially outward DR from the first hole 43. Each of the plurality of second holes 44 penetrates the case body 41 in the axial direction DA. In the illustrated reduction gear 10, the shaft portion of the bolt B2 connecting the case body 41 and the case flange 42 can pass through the second hole 44.

[0049] The case body 41 in Figures 1 and 2 includes a plurality of internal tooth pins 45 held on its inner circumferential surface. The inner circumferential surface of the case body 41 is provided with a plurality of pin grooves arranged in the circumferential direction DC. Each of the plurality of pin grooves extends in the axial direction DA. One of the plurality of internal tooth pins 45 is housed in one of the plurality of pin grooves. When housed in a pin groove, the internal tooth pin 45 is rotatable relative to the case body 41 about a rotation axis extending in the axial direction DA.

[0050] The case body 41 in Figure 1 includes an inward projection 46 in the radial direction DR. The inward projection 46 is a portion of the case body 41 in the axial direction DA. The case body 41 extends inward in the radial direction DR at the inward projection 46 compared to the portion other than the inward projection 46. The first hole 43 is reduced in diameter by the inward projection 46. In other words, the outer diameter of the first hole 43 is reduced by the inward projection 46. The inward projection 46 extends in the circumferential direction DC. The inward projection 46 has a dimension LC in the axial direction DA.

[0051] In Figure 1, the case body 41 forms a first case surface 401 and a second case surface 402 of the case 40 at the inner projection 46. The first case surface 401 and the second case surface 402 are separated from each other in the axial direction DA. Each of the first case surface 401 and the second case surface 402 is a circumferential surface facing the axial direction DA.

[0052] In the reduction gear 10 of Figure 1, the first case surface 401 and the second case surface 402 are located between the first carrier surface 201 and the second carrier surface 202 in the axial direction DA. In the case 40 of Figure 1, the first case surface 401 and the second case surface 402 are surfaces for restricting the movement of the main bearing 30 in the axial direction DA. The first case surface 401 and the second case surface 402 are surfaces for pushing the main bearing 30 in the axial direction DA.

[0053] In Figure 1, the case body 41 forms a third case surface 403 and a fourth case surface 404 of the case 40 in portions other than the inner protrusion 46. The third case surface 403 and the fourth case surface 404 are separated from each other in the axial direction DA. Each of the third case surface 403 and the fourth case surface 404 is a circumferential surface facing the radial direction DR. In the case 40 of Figure 1, the third case surface 403 and the fourth case surface 404 are surfaces that restrict the outward movement of the main bearing 30 in the radial direction DR.

[0054] The case flange 42 in Figure 1 is connected to the case body 41. The case flange 42 is located between the case body 41 and the carrier flange 22 in the axial direction DA. The case flange 42 is provided with a first hole 47a that penetrates the case flange 42 in the axial direction DA. The illustrated case flange 42 accommodates a portion of the carrier body 21 and a portion of the sealing member 50 at the first hole 47a. The case flange 42 with the first hole 47a has an inner circumferential surface centered on the rotation axis RA.

[0055] The case flange 42 in Figure 1 is provided with a plurality of second holes 47b arranged in the circumferential direction DC. The second holes 47b are located further outward in the radial direction DR than the first holes. The second holes 47b penetrate the case flange 42 in the axial direction DA. As shown in Figure 1, the second holes 47b overlap with the second holes 44 provided in the case body 41 in the axial direction DA. The second holes 47b provided in the case flange 42 are adjacent to the second holes 44 provided in the case body 41 in the axial direction DA. As a result, in the illustrated case 40, the shaft portion of the bolt B2 connecting the case body 41 and the case flange 42 can pass through the second holes 47b provided in the case flange 42 and the second holes 44 provided in the case body 41.

[0056] In the case flange 42 shown in Figures 1 and 3, a portion of the inner circumferential surface is a pressing surface 48 that presses against the sealing member 50 from the outside in the radial direction DR. The case flange 42 includes a pressing surface 48 that contacts the sealing member 50. The illustrated pressing surface 48 is inclined with respect to the axial direction DA. In the illustrated case flange 42, the distance of the inclined pressing surface 48 from the rotation axis RA gradually decreases as it approaches the case body 41 in the axial direction DA.

[0057] The case flange 42 in Figure 3 includes a restricting portion 49 that restricts the movement of the sealing member 50 in the axial direction DA. The illustrated restricting portion 49 is located in the axial direction DA between a projection 25 formed by the carrier base 23 and the contact position between the case flange 42 and the sealing member 50. The case flange 42 protrudes radially inward from the pressing surface 48 at the restricting portion 49.

[0058] The gearbox 10 in Figure 1 includes a plurality of main bearings 30. The main bearings 30 are annular members centered on the axis of rotation RA. The gearbox 10 in Figure 1 includes a first main bearing 31 and a second main bearing 32 as the plurality of main bearings 30, which are spaced apart from each other in the axial direction DA.

[0059] The main bearing 30 in Figure 1 includes a first bearing surface 301 and a second bearing surface 302 that are separated from each other in the axial direction DA. Each of the first bearing surface 301 and the second bearing surface 302 is oriented in the axial direction DA. The illustrated main bearing 30 is connected to the carrier 20 at the first bearing surface 301. The main bearing 30 is connected to the case 40 at the second bearing surface 302.

[0060] The main bearing 30 in Figure 1 includes an inner circumferential surface 303 and an outer circumferential surface 304 that are separated from each other in the radial direction DR. Each of the inner circumferential surface 303 and the outer circumferential surface 304 faces in the radial direction DR. The illustrated main bearing 30 is connected to the carrier 20 from the outside in the radial direction DR at the inner circumferential surface 303. The main bearing 30 is connected to the case body 41 from the inside in the radial direction DR at the outer circumferential surface 304.

[0061] Each of the multiple main bearings 30 shown in Figure 1 includes an inner ring 33, an outer ring 34, and rolling elements 35 arranged between the inner ring 33 and the outer ring 34. Each of the inner ring 33 and the outer ring 34 is an annular member extending in the circumferential direction DC. In the reduction gear 10 of Figure 1, the inner ring 33 is fixed to the carrier 20. The outer ring 34 is fixed to the case 40. One member of the inner ring 33 and the outer ring 34 is rotatable about the axis of rotation RA relative to the other member of the inner ring 33 and the outer ring 34 by the rolling elements 35 arranged between the inner ring 33 and the outer ring 34. The main bearing 30 may include a plurality of rolling elements 35 arranged in the circumferential direction DC.

[0062] In the main bearing 30 shown in Figures 1 and 3, the inner ring 33 includes a portion that overlaps with the outer ring 34 in the axial direction DA. The outer ring 34 includes a portion that overlaps with the inner ring 33 in the axial direction DA. The rolling elements 35 include a portion located between the inner ring 33 and the outer ring 34 in the axial direction DA. The inner ring 33 constitutes the first bearing surface 301 and the inner circumferential surface 303 of the main bearing 30. The outer ring 34 constitutes the second bearing surface 302 and the outer circumferential surface 304 of the main bearing 30.

[0063] In the reduction gear 10 of Figure 3, the first main bearing 31 is located between the first carrier surface 201 and the first case surface 401 in the axial direction DA. The second main bearing 32 is located between the second carrier surface 202 and the second case surface 402 in the axial direction DA. The first bearing surface 301 of the first main bearing 31 is in contact with the first carrier surface 201 from the second side in the axial direction DA. The second bearing surface 302 of the first main bearing 31 is in contact with the first case surface 401 from the first side in the axial direction DA. The second bearing surface 302 of the second main bearing 32 is in contact with the second case surface 402 from the second side in the axial direction DA.

[0064] In the gearbox 10 of Figure 3, the first main bearing 31 is located between the third carrier surface 203 and the third case surface 403 in the radial direction DR. The second main bearing 32 is located between the fourth carrier surface 204 and the fourth case surface 404 in the radial direction DR. The inner circumferential surface 303 of the first main bearing 31 is in contact with the third carrier surface 203 from the outside in the radial direction DR. The outer circumferential surface 304 of the first main bearing 31 is in contact with the third case surface 403 from the inside in the radial direction DR. The inner circumferential surface 303 of the second main bearing 32 is in contact with the fourth carrier surface 204 from the outside in the radial direction DR. The outer circumferential surface 304 of the second main bearing 32 is in contact with the fourth case surface 404 from the inside in the radial direction DR.

[0065] The main bearing 30 may be a tapered roller bearing or an angular contact bearing. In Figure 1, the main bearing 30 is pressed axially DA between the carrier 20 and the case 40. In particular, the main bearing 30 is pressed axially DA between the carrier body 21 and the case body 41. The first main bearing 31 is pressed axially DA between a projection 25 provided on the carrier base 23 and an inner projection 46 on the case body 41. The second main bearing 32 is pressed axially DA between a projection 25 provided on the carrier plate 24 and an inner projection 46 on the case body 41. Although tapered roller bearings and angular contact bearings are given as examples for the main bearing 30, it is not limited to these, and a general bearing can be used.

[0066] The sealing member 50 in Figures 1 and 2 seals the space between the carrier 20 and the case 40. The sealing member 50 suppresses the outflow of lubricating oil placed between the carrier 20 and the case 40. The sealing member 50 prevents foreign matter such as dust, soil, and wastewater from flowing between the carrier 20 and the case 40, and prevents the lubricating oil from being contaminated by foreign matter. The sealing member 50 suppresses poor lubrication in the reducer 10 due to contaminated oil.

[0067] The sealing member 50 in Figures 1 and 3 is located on the first side of the main bearing 30 in the axial direction DA, similar to the connection surface 200 described above. That is, the connection surface 200 of the carrier body 21 and the carrier flange 22 is located on the same side as the sealing member 50 in the axial direction DA with respect to the main bearing 30.

[0068] The seal member 50 in Figures 1 and 3 overlaps with the main bearing 30 in the axial direction DA. In other words, the seal member 50 is located in the same region as the main bearing 30 in the radial direction DR. To put it another way, the seal member 50 is located between the inner circumferential surface 303 and the outer circumferential surface 304 of the main bearing 30 in the radial direction DR. In particular, the illustrated seal member 50 overlaps with the inner ring 33 of the main bearing 30 in the axial direction DA. In a reduction gear 10 where the main bearing 30, particularly the inner ring 33, and the seal member 50 overlap in the axial direction DA, the outward protrusion in the radial direction DR of the portion where the seal member 50 is located can be suppressed, and the increase in the radial DR of the reduction gear 10 can be suppressed.

[0069] The sealing member 50 in Figures 1 and 3 includes a first sealing member 51 and a second sealing member 52 that overlaps the first sealing member 51 in the axial direction DA. The first sealing member 51 and the second sealing member 52 are in contact with each other at an annular contact surface 55. The first sealing member 51 and the second sealing member 52 are separated radially DR from the carrier body 21. In the illustrated reduction gear 10, the first sealing member 51 is located in a recess 27 provided in the carrier flange 22. The second sealing member 52 is located at least partially in a first hole 47a provided in the case flange 42. The contact surface 55 is separated by a distance LE from the second surface 222 of the carrier flange 22 in the axial direction DA.

[0070] The first sealing member 51 and the second sealing member 52 shown in Figures 1 and 3 each include a first ring 53 and a second ring 54 held on the first ring 53. Each of the first ring 53 and the second ring 54 is annular. The illustrated sealing member 50 includes two first rings 53 and two second rings 54. The illustrated first sealing member 51 and the second sealing member 52 have the same configuration as each other. Contrary to the illustration, the first sealing member 51 and the second sealing member 52 may have different configurations as shown.

[0071] As shown in Figures 1 and 3, the outer circumferential surface of the first ring 53 is provided with a recess 56 for accommodating the second ring 54. The first ring 53 is recessed inward in the radial direction DR within the recess 56. In Figure 3, both ends of the first ring 53 in the axial direction DA protrude outward in the radial direction DR due to the presence of the recess 56. The first ring 53 may restrict the movement of the second ring 54 in the axial direction DA relative to the first ring 53 by such protrusions at both ends in the axial direction DA.

[0072] In the first sealing member 51 and the second sealing member 52 in Figures 1 and 3, the second ring 54 is positioned on the recess 56 of the first ring 53. The first ring 53 supports the second ring 54 when it is pressed. From the viewpoint of stably supporting the second ring 54, the first ring 53 may be made of a metal such as chromium-molybdenum steel.

[0073] In the gearbox 10 shown in Figures 1 and 3, the second ring 54 of the first seal member 51 is located radially DR between the carrier flange 22 and the first ring 53. The second ring 54 of the second seal member 52 is located radially DR between the case flange 42 and the first ring 53. The second ring 54 contains a compressible material. In the illustrated first seal member 51, the second ring 54 is compressively deformed between the carrier flange 22 and the first ring 53. In the illustrated second seal member 52, the second ring 54 is compressively deformed between the case flange 42 and the first ring 53. The second ring 54 may contain rubber as the compressible material.

[0074] The sealing member 50 in Figures 1 and 3 is pressed in the axial direction DA between the carrier 20 and the case 40. In particular, the sealing member 50 is pressed in the axial direction DA between the carrier flange 22 and the case flange 42.

[0075] In Figures 1 and 3, the carrier flange 22 presses the first sealing member 51 at the pressing surface 28 located in the recess 27. The carrier flange 22 presses the first sealing member 51 in a direction perpendicular to the pressing surface 28. In the first sealing member 51, the second ring 54 is compressed and deformed by being pressed by the carrier flange 22.

[0076] As described above, the pressing surface 28 is inclined with respect to the axial direction DA. Due to the inclination of the pressing surface 28, the force with which the carrier flange 22 presses the first seal member 51 includes a component that pushes the first seal member 51 radially DR and a component that pushes the first seal member 51 axially DA. The component that pushes the first seal member 51 radially DR pushes the first seal member 51 inward in the radial direction DR. The component that pushes the first seal member 51 axially DA pushes the first seal member 51 toward the second seal member 52. Therefore, the carrier flange 22 is pushing the first seal member 51 toward the second seal member 52 axially DA.

[0077] Furthermore, as described above, the radial distance DR between the inclined pressing surface 28 and the rotation axis RA gradually decreases as it approaches the second surface 222. As a result, in the illustrated carrier flange 22, by bringing the contact position with the first seal member 51 closer to the second surface 222, the amount of deformation of the second ring 54 of the first seal member 51 and the force pressing the first seal member 51 increase. The increase in the force pressing the first seal member 51 results in an increase in the force with which the first seal member 51 presses the second seal member 52 in the axial direction DA.

[0078] In Figures 1 and 3, the case flange 42 presses against the second sealing member 52 at the pressing surface 48. The case flange 42 presses against the second sealing member 52 in a direction perpendicular to the pressing surface 48. In the second sealing member 52, the second ring 54 is compressed and deformed by being pressed by the case flange 42.

[0079] As described above, the pressing surface 48 of the case flange 42 is inclined with respect to the axial direction DA. Due to the inclination of the pressing surface 48, the force with which the case flange 42 presses the second seal member 52 includes a component that pushes the second seal member 52 radially DR and a component that pushes the second seal member 52 axially DA. The component that pushes the second seal member 52 radially DR pushes the second seal member 52 inward in the radial direction DR. The component that pushes the second seal member 52 axially DA pushes the second seal member 52 toward the first seal member 51. Therefore, the case flange 42 is pushing the second seal member 52 toward the first seal member 51 axially DA.

[0080] Furthermore, as described above, the radial distance DR between the inclined pressing surface 48 and the rotation axis RA gradually decreases as it approaches the restricting portion 49. As a result, in the illustrated case flange 42, by bringing the contact position with the second seal member 52 closer to the restricting portion 49, the amount of deformation of the second ring 54 of the second seal member 52 and the force pressing the second seal member 52 increase. The increase in the force pressing the second seal member 52 results in an increase in the force with which the second seal member 52 presses the first seal member 51 in the axial direction DA.

[0081] As a result of the above, in the seal member 50 of Figures 1 and 3, one of the first seal member 51 and the second seal member 52 is pressed in the axial direction DA toward the other of the first seal member 51 and the second seal member 52. As described above, the seal member 50 is pressed in the axial direction DA between the carrier flange 22 and the case 40. The contact surface 55 is the surface on which the first seal member 51 presses the second seal member 52 in the axial direction DA, and the surface on which the second seal member 52 presses the first seal member 51 in the axial direction DA. The contact surface 55 is located in the axial direction DA between the contact position between the first seal member 51 and the carrier flange 22, and the contact position between the second seal member 52 and the case flange 42. In the illustrated reduction gear 10, the contact surface 55 is located in the axial direction DA between the pressing surface 28 of the carrier flange 22 and the pressing surface 48 of the case flange 42.

[0082] Incidentally, variations in dimensions and other characteristics can occur in the carrier and case manufactured as components of the gearbox. For example, in the carrier 20 shown in Figures 1 and 3, variations can occur in the inclination angle of the pressing surface 28 that presses against the first seal member 51 with respect to the axial direction DA. For example, in the case 40 shown in Figures 1 and 3, variations can occur in the inclination angle of the pressing surface 48 that presses against the second seal member 52 with respect to the axial direction DA. Variations in the inclination angle of the pressing surface 28 in the carrier 20 and variations in the inclination angle of the pressing surface 48 in the case 40 can cause changes in the pressure applied to the seal member 50 in the axial direction DA.

[0083] In the gearbox 10 shown in Figures 1 and 3, the axial pressure DA on the seal member 50 can be adjusted by adjusting the distance LB between the first surface 221 and the second surface 222 of the carrier flange 22. For example, the distance LB can be reduced to increase the pressure exerted by the carrier flange 22 on the seal member 50 in the axial direction DA.

[0084] Figure 4 illustrates the mechanism of the increase in axial pressure DA on the sealing member 50 by the carrier flange 22. In Figure 4, the distance LB between the first surface 221 and the second surface 222 decreases from LB1 to LB2. As a result of the reduction in distance LB, the distance LE between the second surface 222 and the contact surface 55 of the sealing member 50 also decreases, as shown in Figure 5. In Figure 4, the distance LE between the second surface 222 and the contact surface 55 decreases from LE1 to LE2. On the other hand, in Figure 4, the position of the sealing member 50 does not change even when the distance LB is reduced. This means that in Figure 4, the carrier flange 22 moves to the second side in the axial DA relative to the sealing member 50 as a result of the reduction in distance LB.

[0085] In Figure 4, as the carrier flange 22 moves, the contact position with the sealing member 50 on the pressing surface 28 approaches the second surface 222 of the carrier flange 22. As described above, the force with which the carrier flange 22 pushes the first sealing member 51 increases as the contact position with the first sealing member 51 approaches the second surface 222. As a result, the pressure exerted by the carrier flange 22 on the sealing member 50 in the axial direction DA increases as the distance LB between the first surface 221 and the second surface 222 of the carrier flange 22 decreases.

[0086] In the gearbox 10 shown in Figures 1 and 3, the pressure exerted by the carrier flange 22 on the sealing member 50 in the axial direction DA can be adjusted by adjusting the distance LB between the first surface 221 and the second surface 222 of the carrier flange 22. The distance LB may be adjusted, for example, by polishing the first surface 221 of the carrier flange 22.

[0087] Furthermore, in the gearbox 10 shown in Figures 1 and 3, the pressure on the sealing member 50 in the axial direction DA can also be adjusted by adjusting the dimensions of the case 40, specifically the distance between the case body 41 and the case flange 42. For example, to increase the pressure exerted by the case flange 42 on the sealing member 50 in the axial direction DA, the distance LF between the case body 41 and the case flange 42 in the axial direction DA can be increased.

[0088] Figure 5 is a diagram illustrating the mechanism of the increase in axial pressure DA on the sealing member 50 by the case flange 42. The reducer 10 in Figure 5 includes a spacer 90 positioned between the case body 41 and the case flange 42. The spacer 90 is an annular member centered on the axis of rotation RA. The spacer 90 has through holes positioned to overlap with the second hole 44 in the case body 41 and the second hole 47b in the case flange 42 in the axial direction DA. The case body 41 and the case flange 42 in Figure 5 are connected via the spacer 90, and are separated in the axial direction DA by the thickness DF of the spacer 90. On the other hand, in Figure 5, even though the case body 41 and the case flange 42 are separated from each other, the position of the sealing member 50 does not change. As a result, in Figure 5, the case flange 42 moves to the first side in the axial direction DA relative to the sealing member 50.

[0089] In Figure 5, as the case flange 42 moves, the contact position with the sealing member 50 on the pressing surface 48 approaches the restricting portion 49 of the case flange 42. As described above, the force with which the case flange 42 presses the second sealing member 52 increases as the contact position with the second sealing member 52 approaches the restricting portion 49. As a result, the pressure with which the case flange 42 presses the sealing member 50 in the axial direction DA increases by placing the spacer 90 between the case body 41 and the case flange 42.

[0090] The crankshaft 60 shown in Figure 1 includes a first eccentric body 61 and a second eccentric body 62 aligned in the axial direction DA. Each of the first eccentric body 61 and the second eccentric body 62 has a cylindrical shape with an axial direction DAE parallel to the axial direction DA. The central axis CA1 of the first eccentric body 61 and the central axis CA2 of the second eccentric body 62 are offset from the rotation axis RAC of the crankshaft 60 in the radial direction DRE, which is perpendicular to the rotation axis RAC. The central axis CA1 of the first eccentric body 61 is offset from the rotation axis RA of the crankshaft 60 in the radial direction DRE. The central axis CA2 of the second eccentric body 62 is offset from the rotation axis RAC of the crankshaft 60 in the radial direction DRE, which is toward the rotation axis RA.

[0091] The crankshaft 60 in Figure 1 includes an input gear 63 positioned at its end in the axial direction DA. The input gear 63 meshes with the gear ZR of the input shaft. Gear ZR and the input gear 63 are separated from each other in the radial direction DR. The illustrated gear ZR and input gear 63 rotate about an axis of rotation parallel to the axial direction DA. The meshing of gear ZR and the input gear 63 transmits the rotation of the input shaft to the crankshaft 60.

[0092] The gearbox 10 in Figure 1 includes two external gears 70 aligned in the axial direction DA. The two external gears 70 are housed in a case 40. The external gears 70 are positioned in the axial direction DA between the carrier plate 24 and the base plate portion 230 of the carrier base 23.

[0093] The external gear 70 in Figures 1 and 2 is provided with a central hole 71 located in the center. The external gear 70 has external teeth 75 arranged along its outer edge. The number of teeth on the external teeth 75 is less than the number of internal tooth pins 45. For example, the number of teeth on the external teeth 75 is exactly one less than the number of internal tooth pins 45.

[0094] The external gear 70 in Figures 1 and 2 is provided with a plurality of eccentric body insertion holes 72 that are spaced apart in the circumferential direction around a central hole 71. Figure 2 shows three eccentric body insertion holes 72 arranged in the circumferential direction. A second bearing 12 is positioned in each of the plurality of eccentric body insertion holes 72. The crankshaft 60 is rotatably held relative to the external gear 70 via the second bearings 12.

[0095] The external gear 70 shown in Figures 1 and 2 has a plurality of column insertion holes 73 arranged at equal intervals in the circumferential direction around a central hole 71. Figure 2 shows three column insertion holes 73 arranged in the circumferential direction. In the external gear 70 shown in Figure 2, the eccentric body insertion holes 72 and column insertion holes 73 are arranged alternately in the circumferential direction. In Figures 1 and 2, the first projection 231 of the carrier base 23 passes through each column insertion hole 73.

[0096] The external gear 70 shown in Figures 1 and 2 has external teeth 75 on its outer circumferential surface. The external gear 70 contacts a plurality of internal tooth pins 45 of the case 40 from its outer circumferential surface, including the external teeth 75. Driven by the crankshaft 60, the external gear 70 moves relative to the case 40 while contacting the internal tooth pins 45 at the external teeth 75. As will be described later, the central axis of the external gear 70 moving relative to the case 40 revolves around the rotation axis RA. The movement of the external gear 70 relative to the case 40 is transmitted to the carrier 20, causing the carrier 20 to rotate about the rotation axis RA relative to the case 40.

[0097] The gearbox 10 in Figures 1 and 3 includes a spacer 80 positioned between the main bearing 30 and the carrier 20. Specifically, the spacer 80 is positioned between the first main bearing 31 and the carrier body 21. More specifically, the spacer 80 is positioned between the first main bearing 31 and the carrier plate 24. The spacer 80 is an annular member having a first spacer surface 81 and a second spacer surface 82. The spacer 80 has a thickness t as the distance between the first spacer surface 81 and the second spacer surface 82 in the axial direction DA. Each of the first spacer surface 81 and the second spacer surface 82 faces the axial direction DA. The spacer 80 is in contact with the first bearing surface 301 of the main bearing 30 at the first spacer surface 81. The spacer 80 is in contact with the second carrier surface 202 of the carrier 20 at the second spacer surface 82.

[0098] In Figures 1 and 3, the first main bearing 31 is in contact with the first carrier surface 201 of the carrier 20 at its first bearing surface 301. The first main bearing 31 is in contact with the first case surface 401 of the case 40 at its second bearing surface 302. As a result, the first main bearing 31 is pushed axially DA toward the inner projection 46 of the case body 41 by the projection 25 provided on the carrier body 21.

[0099] In Figures 1 and 3, the second main bearing 32 is in contact with the first spacer surface 81 of the spacer 80 at its first bearing surface 301. The second main bearing 32 is in contact with the second case surface 402 of the case 40 at its second bearing surface 302. As a result, the second main bearing 32 is pushed axially DA toward the inner projection 46 of the case body 41 by the spacer 80 and the carrier body 21 connected to the spacer 80. Furthermore, the second main bearing 32 is pushed axially DA toward the spacer 80 and the carrier body 21 connected to the spacer 80 by the inner projection 46 of the case body 41.

[0100] Incidentally, variations in dimensions can occur in the carriers and cases manufactured as components of the speed reducer. Variations in axial dimensions can occur between multiple cases. Variations in axial dimensions can occur between multiple carriers. For example, in the carrier 20 shown in Figures 1 and 3, variations can occur in the distance LA in the axial direction DA between the first carrier surface 201 and the second carrier surface 202. For example, in the case 40 shown in Figures 1 and 3, variations can occur in the dimension LC of the inner projection 46 of the case body 41 in the axial direction DA. Due to these variations in the axial direction DA of the carrier 20 and case 40, the pressure pushing the main bearing 30 in the axial direction DA can change in the speed reducer 10 shown.

[0101] In the gearbox 10 shown in Figures 1 and 3, the pressure on the main bearing 30 in the axial direction DA is adjusted by adjusting the thickness t of the spacer 80. In the illustrated gearbox 10, by arranging the spacer 80, the dimension LD1 in the axial direction DA of the space for arranging the first main bearing 31 and the dimension LD2 in the axial direction DA of the space for arranging the second main bearing 32 are reduced. On the other hand, in the illustrated gearbox 10, the dimension LC in the axial direction DA of the inner protrusion 46 of the case body 41 is less affected by the change in the thickness t of the spacer 80 compared to the above-mentioned dimensions LD1 and LD2.

[0102] In the gearbox 10 shown in Figures 1 and 3, the axial pressure DA on the first main bearing 31 increases as the distance LD1 between the first carrier surface 201 and the first case surface 401 decreases. Similarly, the axial pressure DA on the second main bearing 32 increases as the distance LD2 between the second spacer surface 82 and the second case surface 402 decreases. Therefore, in the illustrated gearbox 10, increasing the thickness t of the spacer 80 increases the axial pressure DA on the first main bearing 31 and the axial pressure DA on the second main bearing 32. As a result, in the illustrated gearbox 10, the axial pressure DA on the main bearing 30 can be adjusted by adjusting the thickness t of the spacer 80.

[0103] Next, the operation of the reduction gear 10 shown in Figures 1 to 3 will be explained. Torque from the input shaft (not shown) is transmitted from the gear ZR to the input gear 63 of the crankshaft 60. The crankshaft 60 rotates around the rotation axis RAC relative to the carrier 20 and case 40 due to the torque transmitted from the input gear 63. In the crankshaft 60 rotating around the rotation axis RAC, the first eccentric body 61 and the second eccentric body 62 rotate eccentrically with respect to the carrier 20 and case 40. The first eccentric body 61 rotates with its central axis CA1 shifted radially DRE relative to the rotation axis RAC. The second eccentric body 62 rotates with its central axis CA2 shifted radially DRE relative to the rotation axis RAC.

[0104] The external gear 70 is driven by the eccentric rotation of the first eccentric body 61 or the second eccentric body 62. The two external gears 70 shown in Figure 2 move radially DR and circumferentially DC relative to the case 40 while contacting the internal tooth pins 45 of the case 40 on their outer surfaces. Each internal tooth pin 45 rotates relative to the case body 41 about a rotation axis parallel to the axial direction DA due to contact with the external gear 70. As described above, the number of teeth of the illustrated external gears 75 is one less than the number of internal tooth pins 45. As a result, in the external gear 70 that moves relative to the case 40, the central axis of the external gear 70 is offset radially DR with respect to the rotation axis RA, and it moves circumferentially DC around the rotation axis RA. In other words, the external gear 70 that moves relative to the case 40 revolves around the rotation axis RA. The orbital period of the external gear 70, that is, the time it takes for the central axis of the external gear 70 to complete one revolution along the trajectory extending in the circumferential direction DC, is greater than the rotational period of the crankshaft 60.

[0105] The orbital motion of the external gear 70 is transmitted to the carrier 20 inserted into the column insertion hole 73. As a result, the carrier 20 rotates around the rotation axis RA relative to the case 40. Since the orbital period of the external gear 70 is greater than the rotational period of the crankshaft 60, the carrier 20 rotates relative to the case 40 at a rotational speed smaller than the rotational speed of the input shaft. In the carrier 20, the carrier body 21 and the carrier flange 22 connected to the carrier body 21 rotate relative to the case 40. Therefore, in the illustrated reduction gear 10, the rotational motion of the carrier 20 relative to the case 40 is output as a rotational motion that is reduced compared to the rotational motion input from the gear ZR of the input shaft.

[0106] In the reduction gear 10 shown in Figures 1 to 3, the rotation of the carrier 20 relative to the case 40 causes the first seal member 51, which is pressed by the pressing surface 28 of the carrier flange 22, to rotate relative to the second seal member 52. The first seal member 51 rotates relative to the second seal member 52 while in contact with the second seal member 52, forming a contact surface 55. In Figures 1 and 3, the seal member 50 seals the space between the carrier 20 and the case 40 even when the first seal member 51 rotates relative to the second seal member 52, thanks to the compressed and deformed second ring 54 and the first and second seal members 51 and 52 that form the contact surface 55. The first seal member 51 remains radially away from the carrier body 21 in the direction DR even when rotating relative to the second seal member 52. The second seal member 52 also remains radially away from the carrier body 21 in the direction DR even when the first seal member 51 rotates relative to the second seal member 52.

[0107] Next, the operation of the speed reducer 10 shown in Figures 1 to 3 will be explained. Specifically, an example of the assembly method of the illustrated speed reducer 10 will be explained. The assembly method of the speed reducer 10 includes, as an example, an assembly step of the speed reducer body 10A, an assembly step of the speed reducer cover 10B, and a connection step of connecting the speed reducer body 10A and the speed reducer cover 10B. In the assembly method of the speed reducer 10 described below, the pressure on the main bearing 30 in the axial direction DA is adjusted during the assembly step of the speed reducer body 10A. During the assembly step of the speed reducer cover 10B, the pressure on the sealing member 50 in the axial direction DA is adjusted.

[0108] First, an example of the assembly process for the reduction gear body 10A will be explained. The external gear 70 is attached to the crankshaft 60 via the second bearing 12. In the reduction gear 10 shown in Figures 1 to 3, two external gears 70 are attached to the crankshaft 60 via the second bearing 12. The first main bearing 31, crankshaft 60 and external gear 70, case body 41, and second main bearing 32 are attached to the carrier base 23 in this order. The crankshaft 60 is attached to the carrier base 23 via the first bearing 11.

[0109] In the assembly process of the reduction gear body 10A, the carrier plate 24 is attached to the carrier base 23 from the second side in the axial direction DA, and the carrier base 23 and the carrier plate 24 are connected. The carrier body 21 is formed by the carrier base 23 and the carrier plate 24 connected to each other. As described above, the movement of the carrier base 23 and the carrier plate 24 relative to each other is restricted by the pin P. As the carrier base 23 and the carrier plate 24 are connected, the main bearing 30 is pushed in the axial direction DA between the carrier body 21 and the case body 41. With the carrier base 23 attached to the carrier plate 24, the crankshaft 60 protrudes from the carrier plate 24 to the second side in the axial direction DA.

[0110] In the assembly process of the gearbox body 10A shown in Figures 1 and 3, a spacer 80 is placed between the carrier base 23 and the carrier plate 24. In the illustrated gearbox body 10A, the axial pressure DA on the main bearing 30 is adjusted during assembly by adjusting the thickness t of the spacer 80. The adjustment of the pressure on the main bearing 30 is completed when the assembly process of the gearbox body 10A is finished.

[0111] Next, an example of the assembly process for the gearbox cover 10B will be described. The first sealing member 51 is connected to the carrier flange 22, which is not connected to the carrier body 21. The first sealing member 51 is connected to the carrier flange 22 so that it contacts the pressing surface 28 provided in the recess 27 of the carrier flange 22 from the second ring 54. The second sealing member 52 is connected to the case flange 42, which is not connected to the case body 41. The second sealing member 52 is connected to the case flange 42 so that it contacts the pressing surface 48 of the case flange 42 from the second ring 54.

[0112] In the assembly process of the gearbox cover 10B, the case flange 42 is connected to the case body 41. The case flange 42 may also be connected to the case body 41 by bolts (not shown) passing through the second hole 47b. Movement between the case body 41 and the case flange 42, which are connected to each other, is restricted.

[0113] In the assembly process of the gearbox cover 10B, the carrier flange 22 is connected to the carrier body 21. The carrier flange 22 is connected to the carrier body 21 by bolts B1. Movement between the carrier body 21 and the carrier flange 22, which are connected to each other, is restricted. The assembly process of the gearbox cover 10B is completed by connecting the carrier flange 22 to the carrier body 21. By connecting the carrier flange 22 to the carrier body 21, the sealing member 50 is pushed axially DA between the carrier flange 22 and the case flange 42, as described above.

[0114] In the gearbox cover 10B shown in Figures 1 and 3, the axial pressure DA on the seal member 50 may be adjusted during assembly by adjusting the distance LB between the first surface 221 and the second surface 222 of the carrier flange 22. Alternatively, the axial pressure DA on the seal member 50 may be adjusted during assembly by placing a spacer 90 between the case body 41 and the case flange 42 and adjusting the thickness LF of the spacer 90. The adjustment of the pressure on the seal member 50 is completed when the assembly process of the gearbox cover 10B is finished.

[0115] As described above, the assembly of the speed reducer 10 shown in Figures 1 and 3 is completed. The speed reducer 10 can be disassembled by reversing the steps described above. One example of a method for disassembling the speed reducer 10 may include the steps of separating the carrier body 21 and the carrier flange 22 from each other, separating the case body 41 and the case flange 42 from each other, and separating the carrier body 21 and the case body 41 from each other.

[0116] In the conventional gearbox illustrated in JP2000-120846A, the carrier is constructed as a single, seamless unit with the portion connecting to the main bearing and the portion connecting to the seal member. Similarly, the case is constructed as a single, seamless unit with the portion connecting to the main bearing and the portion connecting to the seal member. When such a carrier and case are connected to each other during the assembly of a conventional gearbox, both the main bearing and the seal member are pushed in the axial direction. Therefore, in the conventional carrier and case, the portion that pushes the main bearing and the portion that pushes the seal member move in conjunction with each other.

[0117] The pressure required for the proper operation of the main bearing may differ from the pressure required for the proper operation of the seal member. However, in conventional carriers and cases, the parts that press on the main bearing and the parts that press on the seal member move in conjunction with each other, making it difficult to adjust the axial pressure on the main bearing and the axial pressure on the seal member separately. In conventional speed reducers, it is difficult to ensure that each of the main bearing and the seal member operates stably.

[0118] In contrast, in the gearbox 10 according to this embodiment shown in Figures 1 to 5, at least one of the carrier 20 and the case 40 includes a main body portion 20M or 40M and a flange portion 20F or 40F. The main bearing 30 is pressed in the axial direction DA between the main body portion 20M of the carrier 20 and the case 40. The sealing member 50 is pressed in the axial direction DA between the flange portion 20F of the carrier 20 and the case 40. Alternatively, the main bearing 30 is pressed in the axial direction DA between the main body portion 40M of the case 40 and the carrier 20. The sealing member 50 is pressed in the axial direction DA between the flange portion 40F of the case 40 and the carrier 20.

[0119] When assembling the illustrated speed reducer 10, as described above, the pressure on the main bearing 30 in the axial direction DA is adjusted, and then the pressure on the sealing member 50 in the axial direction DA is adjusted. The pressure on the main bearing 30 is adjusted in the assembly process of the speed reducer body 10A by adjusting the thickness t of the spacer 80. The pressure on the sealing member 50 is adjusted in the assembly process of the speed reducer cover 10B by adjusting the dimension LB of the carrier flange 22 or by adjusting the thickness LF of the spacer 90. Therefore, in the illustrated speed reducer 10, the pressure on the main bearing 30 in the axial direction DA and the pressure on the sealing member 50 in the axial direction DA can be adjusted separately. This enables the speed reducer 10 to achieve stable operation of the main bearing 30 and the sealing member 50.

[0120] In the gearbox 10 shown in Figures 1 to 5, the carrier 20 includes a main body 20M (carrier body 21) and a flange portion 20F (carrier flange 22) connected to the main body 20M. The case 40, similar to the carrier 20, includes a main body 40M (case body 41) and a flange portion 40F (case flange 42) connected to the main body 40M. The main bearing 30 is pressed axially DA between the carrier body 21 and the case body 41. The sealing member 50 is pressed axially DA between the carrier flange 22 and the case flange 42. In such a gearbox 10, the axial pressure DA on the sealing member 50 can be adjusted by both the carrier 20 including the carrier flange 22 and the case 40 including the case flange 42. More specifically, the axial pressure DA on the sealing member 50 can be adjusted by adjusting the dimension LB of the carrier flange 22 and the thickness LF of the spacer 90. This allows for precise adjustment of the pressure on the sealing member 50.

[0121] However, in order to stabilize the operation of the main bearing 30 and the sealing member 50 in the illustrated reduction gear 10, at least one of the carrier 20 and the case 40 may include a main body portion 20M or 40M and a flange portion 20F or 40F. For example, in the carrier 20, the carrier body 21 and the carrier flange 22 may be seamlessly integrated. Alternatively, in the case 40, the case body 41 and the case flange 42 may be seamlessly integrated. These examples also allow for more stable operation of the main bearing and the sealing member compared to conventional reduction gears.

[0122] In the speed reducer 10 shown in Figures 1 to 5, the main bearing 30 includes an inner ring 33, an outer ring 34, and a plurality of rolling elements 35 arranged between the inner ring 33 and the outer ring 34. The sealing member 50 overlaps with the inner ring 33 in the axial direction DA. As described above, the illustrated speed reducer 10 can suppress the expansion of the overall dimension in the radial direction DR by suppressing the outward protrusion of the sealing member 50 in the radial direction DR. Furthermore, the illustrated sealing member 50 can suppress the increase in the rotational speed relative to each other at the contact surface 55 of the first sealing member 51 and the second sealing member 52 by suppressing the outward expansion of the dimension in the radial direction DR. As a result, the illustrated speed reducer 10 can also improve the durability of the sealing member 50. In the illustrated speed reducer 10, the sealing member 50 overlaps with the inner ring 33 of the first main bearing 31 and the inner ring 33 of the second main bearing 32 in the axial direction DA. To improve the durability of the sealing member 50 as described above, the sealing member 50 only needs to overlap with at least one of the inner rings 33 of the first main bearing 31 and the second main bearing 32 in the axial direction DA.

[0123] In the gearbox 10 shown in Figures 1 to 5, the connection surface 200 between the carrier body 21 and the carrier flange 22 is located on the same side as the seal member 50 with respect to the main bearing 30. Both the connection surface 200 and the seal member 50 are located on the first side in the axial direction DA with respect to the main bearing 30. When replacing the seal member 50 of the illustrated gearbox 10, the seal member 50 can be replaced by removing the bolt B1 and the carrier flange 22 on the first side in the axial direction DA. On the other hand, in the illustrated gearbox 10, it is not necessary to disconnect the connection between the carrier base 23 and the carrier plate 24 when replacing the seal member 50. When replacing the seal member 50, it is not necessary to remove the carrier plate 24 on the second side in the axial direction DA. The illustrated gearbox 10 can maintain the main bearing 30 pushed in the axial direction DA even when replacing the seal member 50. Therefore, by arranging the connection surface 200, the sealing member 50, and the main bearing 30 in this manner, the sealing member 50 can be efficiently replaced without releasing the axial pressure DA on the main bearing 30. The sealing member 50 may be replaced more frequently than the main bearing 30 due to contact with foreign matter such as dust, soil, and wastewater. The illustrated reduction gear 10 can improve maintenance efficiency by enabling efficient replacement of the sealing member 50.

[0124] In the embodiment described above, the gearbox 10 includes a case 40, a carrier 20 at least partially disposed within the case 40, a main bearing 30 disposed between the case 40 and the carrier 20, and a sealing member 50 that seals the space between the carrier 20 and the case 40. At least one of the carrier 20 and the case 40 includes a body portion 20M or 40M and a flange portion 20F or 40F. The main bearing 30 is pressed axially DA between the body portion 20M of the carrier 20 and the case 40. The sealing member 50 is pressed axially DA between the flange portion 20F of the carrier 20 and the case 40. Alternatively, the main bearing 30 is pressed axially DA between the body portion 40M of the case 40 and the carrier 20. The sealing member 50 is pressed axially DA between the flange portion 40F of the case 40 and the carrier 20.

[0125] Furthermore, in the embodiment described above, the reduction gear 10 includes a case 40, a carrier 20 at least partially disposed within the case 40, a main bearing 30 disposed between the case 40 and the carrier 20, and a sealing member 50 that seals the space between the carrier 20 and the case 40. The carrier 20 includes a carrier body 21 and a carrier flange 22 connected to the carrier body 21. The case 40 includes a case body 41 and a case flange 42 connected to the case body 41. The assembly method for the reduction gear 10 includes the steps of pressing the main bearing 30 disposed between the carrier body 21 and the case body 41, connecting the case flange 42 to the case body 41 and connecting the carrier flange 22 to the carrier body 21, and pressing the sealing member 50 disposed between the carrier flange 22 and the case flange 42.

[0126] According to these embodiments, the pressure on the sealing member 50 in the axial direction DA can be adjusted after the adjustment of the pressure on the main bearing 30 in the axial direction DA is complete. This allows the pressure on the main bearing 30 in the axial direction DA and the pressure on the sealing member 50 in the axial direction DA to be adjusted separately.

[0127] Although one embodiment has been described with reference to specific examples, the above-mentioned example does not limit the embodiment. The above-described embodiment can be implemented in various other examples, and various omissions, substitutions, modifications, and additions can be made without departing from its essence.

[0128] Among the embodiments disclosed herein, those composed of multiple objects may be integrated, and conversely, those composed of a single object may be divided into multiple objects. Whether or not they are integrated, the invention can be constructed in a way that achieves its objective.

[0129] In the embodiments disclosed herein, those in which multiple functions are provided in a distributed manner may have some or all of those multiple functions integrated into a single unit, and conversely, those in which multiple functions are integrated may have some or all of those functions provided in a distributed manner. Whether the functions are integrated or distributed, the configuration should be such that the objective of the invention can be achieved. [Explanation of Symbols]

[0130] 10: Reducer, 10A: Reducer body, 10B: Reducer cover, 20: Carrier, 20F: Flange section (first flange section), 20M: Body section (first body section), 21: Carrier body, 22: Carrier flange, 23: Carrier base, 24: Carrier plate, 25: Protrusion, 27: Recess, 28: Pressing surface, 29: Regulating section, 30: Main bearing, 31: First main bearing, 32: Second main bearing 33: Inner ring, 34: Outer ring, 35: Rolling element, 40: Case, 40F: Flange section (second flange section), 40M: Main body section (second main body section), 41: Case body, 42: Case flange, 48: Pressing surface, 49: Regulating section, 50: Seal member, 51: First seal member, 52: Second seal member, 53: First ring, 54: Second ring, 55: Contact surface, RA: Rotation axis, RAC: Rotation axis

Claims

1. The case and A carrier, at least partially, is located within the aforementioned case. A main bearing is positioned between the case and the carrier, A sealing member that seals the space between the carrier and the case is provided, One of the carrier and the case rotates relative to the other of the carrier and the case about a rotation axis. The aforementioned one member includes a main body and a flange connected to the main body, The main bearing is pressed between the main body and the other member in an axial direction parallel to the axis of rotation. The sealing member is a reduction gear that is pressed in the axial direction between the flange portion and the other member.

2. The other member includes a second main body and a second flange connected to the second main body. The main bearing is pressed in the axial direction between the main body and the second main body. The reduction gear according to claim 1, wherein the sealing member is pressed in the axial direction between the flange portion and the second flange portion.

3. The main bearing includes an inner ring, an outer ring, and a plurality of rolling elements disposed between the inner ring and the outer ring. The reduction gear according to claim 1, wherein the sealing member overlaps with the inner ring in the axial direction.

4. The gearbox according to claim 1, wherein the connection surface between the flange portion and the main body portion is located on the same side as the sealing member in the axial direction with respect to the main bearing.

5. The aforementioned one member includes a connecting portion that connects the main body portion and the flange portion, The reduction gear according to claim 1, wherein the connecting portion is located radially inward with respect to the sealing member, perpendicular to the axis of rotation.

6. The gearbox according to claim 1, wherein the flange portion includes a restricting portion that restricts the axial movement of the sealing member.

7. A case including a case body and a case flange connected to the case body, A carrier including a carrier body and a carrier flange connected to the carrier body, which is at least partially disposed within the case, A main bearing is positioned between the case and the carrier, A method for assembling a speed reducer comprising a sealing member that seals the space between the carrier and the case, A step of pressing the main bearing which is positioned between the carrier body and the case body, The steps include connecting the case flange to the case body and connecting the carrier flange to the carrier body, A method for assembling a speed reducer, comprising the step of pressing the sealing member positioned between the carrier flange and the case flange.

Images