JP6368685B2 - Reduction gear - Google Patents

Description

  The present invention relates to a speed reducer suitably used for a hydraulic excavator, a hydraulic crane traveling device, and the like.

  Generally, a lower traveling body of a tracked vehicle such as a hydraulic excavator is provided with a track frame having left and right side frames, a traveling device provided at one end side of each side frame, and a second end side of each side frame. And a crawler belt wound between the idler wheel and a drive wheel (sprocket) provided in the traveling device.

  In this case, the traveling device of the hydraulic excavator is usually composed of a hydraulic motor serving as a rotation source and a speed reducer that decelerates and outputs the rotation of the hydraulic motor, and this speed reducer has an output provided with a female spline portion. A stationary housing housing a rotation source having a shaft; a rotation housing provided rotatably with respect to the stationary housing; and driven by the rotation source; and rotation of the rotation source housed in the rotation housing. A first-stage planetary gear reduction mechanism that decelerates the first-stage planetary gear reduction mechanism disposed between the rotation source and the first-stage planetary gear reduction mechanism to reduce the rotation of the first-stage planetary gear reduction mechanism. And a second-stage planetary gear reduction mechanism that rotates the side housing.

  The first-stage planetary gear speed reduction mechanism is provided with a male spline portion extending in the axial direction in the rotation side housing and splined to the female spline portion of the output shaft on one side in the axial direction. And a first sun gear provided on the other side in the axial direction of the rotation shaft, and an internal gear provided on the inner peripheral side of the rotation side housing. A plurality of first planetary gears that revolve while rotating around the first sun gear, and a first carrier that rotatably supports the first planetary gears.

  Further, the second stage planetary gear speed reduction mechanism is formed of a cylindrical body having a through hole through which the rotating shaft is inserted, and is disposed between the female spline portion of the output shaft and the first sun gear. And a second sun gear connected to the first carrier, and the second sun gear and an inner gear provided on the inner peripheral side of the rotary housing, and surrounding the second sun gear. A plurality of second planetary gears that rotate the rotation-side housing by rotating in rotation, and a second carrier that is attached to the fixed-side housing in a non-rotating state and rotatably supports the second planetary gears. (For example, refer to Patent Document 1 and Patent Document 2).

JP 2000-009017 A JP 2009-68506 A

  By the way, in the above-described prior art, the end surface of the first sun gear is brought into contact with the sliding body attached to the inner surface of the cover that closes the rotation side housing, and the first sun gear and the second sun gear are A sliding member is provided between which both are slidable. In this case, the sliding member according to the prior art is formed of an annular body having a central portion serving as a shaft insertion hole, and the sliding member has a shaft insertion hole on one side in the axial direction of the rotation shaft provided with the male spline portion. Is inserted into the first sun gear provided on the other side in the axial direction of the rotating shaft. Therefore, in order to form a sliding member on which the first sun gear can slide stably, it is necessary to set a large difference in size between the outer diameter of the first sun gear and the outer diameter of the male spline portion. In order to obtain a large reduction ratio, it is difficult to reduce the outer diameter of the first sun gear.

  On the other hand, a small-diameter shaft portion (constriction portion) smaller in diameter than the male spline portion is formed in the vicinity of the first sun gear on the rotating shaft, and two half-sliding slides obtained by dividing the annular body A method is conceivable in which a member is formed and the small-diameter shaft portion of the rotating shaft is sandwiched from the radial direction by each half-shaped sliding member. By using the sliding member divided into two, even when the outer diameter of the first sun gear is reduced, the first sun gear can be stably brought into contact with the sliding member, and a large reduction ratio can be obtained. Can be obtained.

  However, when the speed reducer is in operation, the first and second sun gears are rotated by the rotation of the rotating shaft, so that centrifugal force acts on the halved sliding member. For this reason, when the sliding body attached to the inner surface of the cover is worn and the rotating shaft moves in the axial direction, the sliding member is detached from the axial center of the rotating shaft in the radial direction, and the first and second There is a possibility that the smooth rotation of the sun gear is hindered.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a speed reducer that can stably rotate the first and second sun gears using a sliding member.

In order to solve the above-described problems, the present invention provides a fixed housing that houses a rotation source having an output shaft provided with a female spline portion, and is rotatably provided with respect to the fixed housing and driven by the rotation source. A rotation-side housing, a first-stage planetary gear reduction mechanism that is housed in the rotation-side housing and decelerates the rotation of the rotation source, and the rotation source and the first-stage planetary gear reduction mechanism And a second-stage planetary gear reduction mechanism that decelerates the rotation of the first-stage planetary gear reduction mechanism and rotates the rotation-side housing, and the first-stage planetary gear reduction mechanism is configured to rotate the rotation-side housing. A rotating shaft provided extending in the axial direction in the side housing and provided with a male spline portion splined to the female spline portion of the output shaft on one side in the axial direction, and the other axial side of the rotating shaft Provided in A plurality of the first sun gear, and the first sun gear and an internal gear provided on the inner peripheral side of the rotation-side housing and revolving while rotating around the first sun gear. The first planetary gear and a first carrier that rotatably supports each first planetary gear, and the second stage planetary gear reduction mechanism has a through hole through which the rotation shaft is inserted. A second sun gear that is formed between the female spline portion of the output shaft and the first sun gear and is connected to the first carrier, and the second sun gear. A plurality of second planetary gears that mesh with the inner gear provided on the inner peripheral side of the rotation side housing and rotate around the second sun gear to rotate the rotation side housing, and the fixed The second housing is attached to the side housing in a non-rotating state. Constituted by a second carrier rotatably supporting the planetary gears, the rotary shaft of the first-stage planetary gear reduction mechanism, one side in the axial direction and the male spline portion, in the axial direction of the other side The present invention is applied to a reduction gear formed as a stepped shaft between the first sun gear and the male spline portion side as a large diameter shaft and the first sun gear side as a small diameter shaft .

The feature of the configuration invention of claim 1 is employed, the prior SL is between the first sun gear second sun gear, the small-diameter shaft of the rotary shaft consists of two halves The first sun gear and the second sun gear are slidably contacted with each other, and a through-hole of the second sun gear is provided in the through hole of the second sun gear. A step is provided at a position facing the sun gear, the first sun gear side is formed as a large-diameter hole with a larger diameter than the step, and the sliding member is the second sun gear. It is set as the structure arrange | positioned in a large diameter hole , The axial direction length dimension (L1) of the small diameter shaft of the said rotating shaft is the axial direction length dimension (L2) of a said 1st planetary gear, and the axis | shaft of the said sliding member It is configured to have a value (L1> L2 + L3) larger than the total length dimension with the direction length dimension (L3), and the axial centerline of the second sun gear The length dimension A1 to the outermost periphery of the moving member is configured to have a value (A1> A2) larger than the length dimension A2 from the axial center line of the second sun gear to the tooth tip of the first planetary gear. The axial length dimension (L1) of the small-diameter shaft of the rotating shaft is the axial length dimension (L3) of the sliding member, the female spline portion of the output shaft, and the male spline of the rotating shaft. That is, it is configured to have a value (L1> L3 + L4) larger than the total length dimension with the axial length dimension (L4) of the spline coupling part with the part .

According to a second aspect of the present invention, the sliding member includes a first half bush and a first half bush that are combined in a cylindrical shape with the small-diameter shaft of the rotating shaft interposed therebetween and inserted into the through hole of the second sun gear. And the radial dimension on the inner diameter side of the first half bush and the radial dimension on the inner diameter side of the second half bush are larger than the radial dimension of the small-diameter shaft. It forms a value, wherein said small-diameter shaft of the rotary shaft first, between the second half inner circumferential surface of the bush, in that the Tei Ru configuration provided radial gap.

According to a third aspect of the present invention, the through hole of the second sun gear forms the male spline part side as a small diameter hole part over the entire length from the step part, and the first sun gear side has the large diameter. forms a hole, the first, second half bush, the said extending small-diameter hole portion in the axial direction half cylindrical portion of the through hole, extending radially outward from the position of the stepped portion The step portion and the flange portion that contacts the end surface of the first sun gear, and the axial length dimension B1 of the half cylinder portion is the same as the step portion of the second sun gear and the first sun gear. In other words, the planetary gear is configured to have a value (B1> B2) larger than the length dimension B2 between the end surface on one side in the axial direction.

According to a fourth aspect of the present invention, the flange portion of the first and second half bushes includes a first sun gear contact surface on which the first sun gear contacts, and the first sun gear contact surface. A second sun gear contact surface that is in contact with the stepped portion of the second sun gear, and the first sun gear contact surface includes the first sun gear and the second sun gear contact surface. This is because it is formed as an uneven surface that increases the contact friction.

According to a fifth aspect of the invention, the flange portion of the first and second half bushes includes a first sun gear abutting surface on which the first sun gear abuts, and the first sun gear abutting surface. A second sun gear abutting surface that is located on the back surface side of the second sun gear and is in contact with the stepped portion of the second sun gear, and a combination surface when the first and second half bushings are combined and wherein the first sun gear contact surface and the corners of intersection lies in the fact that the Ru Tei provided chamfered portion formed by notching the angle corner.

  According to the first aspect of the present invention, even if the rotating shaft moves in the axial direction within the through hole of the second sun gear, the sliding member composed of two halves is prevented from falling off the rotating shaft. This sliding member can be held in the large-diameter hole of the second sun gear. As a result, the first and second sun gears can be reliably brought into contact with the sliding member, and the first and second sun gears can be smoothly rotated over a long period of time.

Further , the first sun gear and the first planetary gear can be disengaged by sliding the rotating shaft in the through hole of the second sun gear. At this time, the sliding member fitted to the small-diameter shaft of the rotating shaft engages with the first planetary gear, thereby restricting further movement in the axial direction. Therefore, when the first sun gear and the first planetary gear are disengaged, the sliding member is prevented from inadvertently falling off the rotating shaft, and the sliding member is moved to the first sun gear and the second sun gear. The sun gear can be fitted to the small-diameter shaft of the rotating shaft. Thus, when the first-stage and second-stage planetary gear reduction mechanisms are assembled to the rotation-side housing, the first sun gear and the second planetary gear are meshed with each other, and then the first freely rotatable first The planetary gear and the internal gear can be meshed. Finally, the first sun gear and the first planetary gear can be meshed. As a result, there is no need to adjust the phases of the teeth simultaneously, so the first and second planetary gear speed reduction mechanisms can be easily assembled to the rotation side housing.

  Moreover, by sliding the rotating shaft within the through hole of the second sun gear, the first sun gear and the first planetary gear are disengaged, and the male spline portion and the female spline portion of the output shaft are Can be disengaged. Thereby, the rotating shaft can be rotated independently, and the first sun gear, the first planetary gear, the male spline portion of the rotating shaft, and the female spline portion of the output shaft are meshed simultaneously with the rotating shaft. The phase of each tooth of the provided male spline part and the first sun gear can be finely adjusted. As a result, the engagement of the male spline portion with the female spline portion of the output shaft and the engagement of the first sun gear with the plurality of first planetary gears can be easily performed. The workability when the planetary gear reduction mechanism is assembled to the rotation side housing can be improved.

According to the invention of claim 2 , since the radial gap is provided between the small-diameter shaft of the rotating shaft and the inner peripheral surface of the first and second half bushes, the first half bush is provided. The second half bush and the rotating shaft are not in contact with each other. Thereby, for example, even when the shaft center of the rotating shaft and the shaft center of the second sun gear are misaligned during the operation of the speed reducer, the first and the first inserted through the through hole of the second sun gear. It can suppress that a 2nd half bush and a 2nd sun gear contact. As a result, since it is possible to suppress a large load from acting on the first and second half bushes from the rotating shaft, the life of the first and second half bushes can be improved.

According to the invention of claim 3 , by forming the first and second half bushes by the half cylinder part and the collar part, the hole diameter of the through hole through which the half cylinder part is inserted is made as much as possible. By making the small-diameter hole portion small, the thickness from the outer peripheral side of the second sun gear to the through hole can be increased (thickened). Thereby, even if a large torque acts on the second sun gear from the first carrier, the torsional strength of the second sun gear can be sufficiently secured, and the durability of the second sun gear can be increased. Can be increased. In addition, since the first and second half bushes can sufficiently secure a sliding surface with the first sun gear by the flange portion, the rotation shaft (first sun gear) can be stably rotated. Can be made.

  In addition, when the rotating shaft is moved in the axial direction within the through hole of the second sun gear in order to disengage the first sun gear and the first planetary gear, the first and second half gears. The flange portion of the split bush engages with the end surface of the first planetary gear before the half cylinder portion is extracted from the small diameter hole portion of the second sun gear. As a result, when the first sun gear and the first planetary gear are disengaged, the first and second half bushes can be prevented from inadvertently falling off the rotating shaft. The workability when the stage and second stage planetary gear speed reduction mechanisms are assembled to the rotation side housing can be improved.

According to the invention of claim 4 , when the first sun gear and the second sun gear rotate relative to each other, the first and second half bushes have a large contact friction (sliding resistance). Therefore, it can slide positively with the step of the second sun gear. As a result, the edge of the first sun gear is prevented from sliding intermittently relative to the first and second half bushes, and the sliding surface of each half bush with the first sun gear is reduced. Since wear can be reduced, the life of each half-bush can be improved.

According to the invention of claim 5 , even if the first half bush and the second half bush are displaced in the axial direction and a step is produced, the end face side portion of the tooth of the first sun gear is chamfered. Since it contacts the part smoothly, it can suppress that the edge of a 1st sun gear catches in this level | step difference. Thereby, while being able to improve the lifetime of the 1st and 2nd half bushings, since a rotating shaft (1st sun gear) can be rotated stably, stability and reliability of a reduction gear Can be improved.

1 is a front view showing a hydraulic excavator provided with a reduction gear according to a first embodiment of the present invention. It is sectional drawing which looked at the traveling apparatus of a lower traveling body from the arrow II-II direction in FIG. It is sectional drawing of the principal part expansion which shows the rotating shaft, the 1st sun gear, the 2nd sun gear, a sliding member, etc. in FIG. It is sectional drawing which shows the dimensional relationship of the small diameter shaft of a rotating shaft, a sliding member, a 1st planetary gear, etc. It is sectional drawing which shows the dimensional relationship of a 1st, 2nd half-bush, a 1st planetary gear, etc. It is sectional drawing of the principal part expansion which shows the state which moved the rotating shaft in FIG. 4 to an axial direction, and has disengaged the 1st sun gear and the 1st planetary gear. It is a perspective view which shows a sliding member (a 1st half bush, a 2nd half bush) alone. It is a disassembled sectional view of the 1st assembly which shows the state which removed the rotating shaft, the 1st sun gear, the 1st planetary gear, and the 2nd sun gear from the 1st career. FIG. 9 is an exploded cross-sectional view illustrating a state in which the second sun gear is assembled to the first carrier from the state illustrated in FIG. 8. FIG. 10 is an exploded cross-sectional view illustrating a state in which the sliding member is fitted to the small-diameter shaft of the rotating shaft from the state illustrated in FIG. 9 and the rotating shaft is inserted into the through hole of the second sun gear. It is sectional drawing of the 1st assembly which shows the state which assembled | attached the 1st planetary gear with the 1st carrier from the state shown in FIG. It is the exploded view which removed the 1st step and the 2nd step planetary gear reduction mechanism from the rotation side housing. It is an assembly figure which shows the state which meshed | coupled the 2nd planetary gear with the 2nd planetary gear assembled in the rotation side housing, and mesh | engaged the 1st planetary gear and the internal gear. FIG. 14 is an assembly diagram showing a state in which the second sun gear meshes with the second planetary gear and the first planetary gear meshes with the internal gear from the state of FIG. 13. It is an assembly figure which shows the state which mesh | engaged the 1st sun gear, the 1st planetary gear, the male spline part of the rotating shaft, and the female spline part of the output shaft. It is a comparative example which shows the rotating shaft which lengthened the large diameter shaft and shortened the small diameter shaft. It is a perspective view which shows the sliding member (a 1st half bush, a 2nd half bush) by the 2nd Embodiment of this invention single-piece | unit. It is sectional drawing which shows the state which penetrated the rotating shaft to which the sliding member by 2nd Embodiment was attached to the through-hole of the 2nd sun gear. It is a perspective view which shows the sliding member (1st half split bush, 2nd half split bush) by the 3rd Embodiment of this invention single-piece | unit. It is sectional drawing which shows the state which penetrated the rotating shaft to which the sliding member by 3rd Embodiment was attached to the through-hole of the 2nd sun gear. It is sectional drawing which shows the state which penetrated the rotating shaft which attached the sliding member by a modification to the through-hole of the 2nd sun gear.

  Hereinafter, the embodiment of the speed reducer according to the present invention will be described in detail with reference to the accompanying drawings, taking as an example the case of applying to a traveling device of a hydraulic excavator.

  1 to 15 show a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a hydraulic excavator that is a typical example of a construction machine. The hydraulic excavator 1 is a self-propelled track-type (crawler type) lower traveling body 2 and swivels on the lower traveling body 2. The upper revolving unit 3 that can be mounted is generally configured. A work device 4 is provided on the front side of the upper swing body 3 so as to be able to move up and down, and the work device 4 is used for excavation work and the like.

  Here, the lower traveling body 2 is provided on one side in the longitudinal direction of the track frame 5 having left and right side frames 5A (only the left side is shown) extending in the front and rear directions, and the side frames 5A. The idle wheel 6 includes a drive wheel (sprocket) 7 provided on the other side in the longitudinal direction of each side frame 5A, and a crawler belt 8 wound between the idle wheel 6 and the drive wheel 7. ing. The drive wheel 7 is fixed to a reduction gear 18 that constitutes a travel device 11 described later by a bolt 9. That is, the driving wheel 7 is attached to each side frame 5A via the traveling device 11, and the crawler belt 8 is driven to go around by the traveling device 11.

  Next, the traveling device 11 will be described.

  Reference numeral 11 denotes a travel device provided between the side frame 5A and the drive wheel 7. The travel device 11 includes a hydraulic motor 12 as a rotation source described later and a speed reduction device described later that decelerates the rotation of the hydraulic motor 12. 18. Then, the traveling device 11 rotates the driving wheel 7 with a large torque by decelerating the rotation of the hydraulic motor 12 by the speed reduction device 18, and the crawler belt 8 wound between the driving wheel 7 and the idler wheel 6. It is to be driven around.

  Reference numeral 12 denotes a variable displacement swash plate type hydraulic motor (hereinafter referred to as a hydraulic motor 12) as a rotation source. The hydraulic motor 12 is accommodated in a fixed-side housing 19 described later. The hydraulic motor 12 is roughly constituted by a cylinder block 13, a plurality of pistons 14, a swash plate 15, an output shaft 16, and the like. The hydraulic motor 12 rotates the output shaft 16 when pressure oil is supplied from a hydraulic pump (not shown).

  One end side of the output shaft 16 is rotatably supported by a lid body 19C of a fixed side housing 19 described later, and the other end side thereof is rotatable by a bearing 20 provided in a shaft insertion hole 19F of the fixed side housing 19 described later. It is supported by. Further, on the other end side of the output shaft 16, a female spline portion 16 </ b> A to which a male spline portion 26 of the rotating shaft 25 described later is spline-coupled is provided.

  Reference numeral 17 denotes a brake device provided on the lid 19 </ b> C side of the fixed-side housing 19, which will be described later. The brake device 17 is a negative brake device that applies a braking force to the cylinder block 13 and the output shaft 16.

  Next, the speed reducer 18 constituting the traveling device 11 will be described.

  Reference numeral 18 denotes a reduction gear that reduces the rotation of the hydraulic motor 12. The reduction gear 18 includes a stationary housing 19, a rotation housing 21, a first stage planetary gear reduction mechanism 24, and a second stage planetary gear reduction mechanism, which will be described later. 32 or the like.

  Reference numeral 19 denotes a fixed-side housing fixed to the side frame 5 </ b> A. In the fixed-side housing 19, a hydraulic motor 12 and a brake device 17 are provided. The fixed-side housing 19 is formed in a bottomed cylindrical shape by a cylindrical portion 19A and a bottom portion 19B, and the open end side of the cylindrical portion 19A is closed by a lid 19C. An annular flange portion 19D is integrally formed on the outer peripheral side of the cylindrical portion 19A, and the flange portion 19D is fixed to the side frame 5A using a bolt or the like. On the outer peripheral side of the bottom portion 19B, a male spline portion 19E that is spline-coupled with a female spline portion 37B2 of a second carrier 37 described later is provided. Further, a shaft insertion hole 19F through which the output shaft 16 is inserted is provided at the center of the bottom portion 19B. A bearing 20 that rotatably supports the output shaft 16 is provided between the shaft insertion hole 19F and the output shaft 16.

  Reference numeral 21 denotes a rotation-side housing provided rotatably with respect to the fixed-side housing 19, and the rotation-side housing 21 is rotationally driven by the hydraulic motor 12 accommodated in the fixed-side housing 19. The rotation-side housing 21 is formed in a bottomed cylindrical shape by a cylindrical portion 21A and a bottom portion 21B, and the opening end side of the cylindrical portion 21A is closed by a lid portion 21C.

  An annular flange 21D is integrally formed on the outer peripheral side of the cylindrical portion 21A, and a driving wheel (sprocket) 7 is fixed to the flange 21D using a bolt 9. Further, an inner gear 21E that meshes with a first planetary gear 29 and a second planetary gear 36, which will be described later, is provided on the inner peripheral side of the cylindrical portion 21A.

  A housing insertion hole 21F through which the stationary housing 19 is inserted is provided at the center of the bottom 21B. A bearing 22 that rotatably supports the fixed housing 19 is provided between the housing insertion hole 21 </ b> F and the fixed housing 19. In addition, a mechanical seal (floating seal) 23 that seals lubricating oil is provided in the rotation-side housing 21 between the housing insertion hole 21F and the fixed-side housing 19 on the flange portion 19D side of the bearing 22. Yes. Furthermore, a sliding body 21G is provided at the center of the inner side surface of the lid 21C so that an end face 28B on the other side in the axial direction of the rotating shaft 25, which will be described later, is slidably contacted.

  Reference numeral 24 denotes a first-stage planetary gear speed reduction mechanism disposed on the lid 21C side in the rotation-side housing 21. The first-stage planetary gear speed reduction mechanism 24 decelerates the rotation of the hydraulic motor 12 and will be described later. The rotation is transmitted to the second stage planetary gear reduction mechanism 32. The first stage planetary gear speed reduction mechanism 24 includes a rotating shaft 25, a first sun gear 28, a first planetary gear 29, a first carrier 30, and the like.

  Reference numeral 25 denotes a rotary shaft that extends in the axial direction in the rotary side housing 21, and the rotary shaft 25 is provided on one side (base end side) in the axial direction and is splined to the female spline portion 16 A of the output shaft 16. A male spline portion 26 to be coupled, a shaft portion 27 extending in the axial direction from the male spline portion 26, and a first sun gear 28 provided on the other axial side (front end side) of the rotary shaft 25. Has been. That is, the rotary shaft 25 is disposed coaxially with the output shaft 16 of the hydraulic motor 12 and rotates integrally with the output shaft 16 of the hydraulic motor 12.

  The shaft portion 27 of the rotary shaft 25 is formed as a stepped shaft in which the male spline portion 26 side is a large diameter shaft 27A and the first sun gear 28 side is a small diameter shaft 27B. The outer diameter of the tooth tip of the male spline portion 26 and the outer diameter of the large diameter shaft 27A are smaller than the diameter of the through hole 34 of the second sun gear 33 described later. Thereby, the male spline part 26 and the shaft part 27 of the rotating shaft 25 are configured to be able to be inserted into a through hole 34 of the second sun gear 33 described later.

  Here, as shown in FIG. 4, the axial length dimension L1 of the small-diameter shaft 27B of the rotary shaft 25 is equal to the axial length dimension L2 of the first planetary gear 29 described later and a sliding member 39 (described later). It is a value (L1> L2 + L3) larger than the total length dimension of the first and second half bushes 40, 41) and the axial length dimension L3. Thus, when the first-stage planetary gear reduction mechanism 24 and the second-stage planetary gear reduction mechanism 32 described later are assembled in the rotation-side housing 21, the first sun gear 28 and the first planetary gear 29 are assembled. It is the structure which can remove | engage with (refer FIG. 14). In this case, the sliding member 39 can be slid from the through hole 34 of the second sun gear 33 toward the other side in the axial direction. Accordingly, the first sun gear 28 has an axial length between the end surface 29A of the first planetary gear 29 and the end surface of the sliding member 39 in the axial length dimension L1 of the small-diameter shaft 27B of the rotary shaft 25. The meshing with the first planetary gear 29 can be released without considering the dimensions.

  Furthermore, if the length dimension in the axial direction of the spline coupling part 26A between the female spline part 16A of the output shaft 16 and the male spline part 26 of the rotating shaft 25 is L4, the axial length dimension of the small-diameter shaft 27B of the rotating shaft 25 will be described. L1 is larger than the total length of the axial length L3 of the sliding member 39 (first and second half bushes 40 and 41) and the axial length L4 of the spline coupling portion 26A. The value is (L1> L3 + L4).

  Reference numeral 28 denotes a first sun gear provided on the other side in the axial direction of the rotary shaft 25. The first sun gear 28 is located in a first carrier 30 described later and is described below as a first planetary gear described later. 29 meshes. The axial length of the first sun gear 28 is slightly larger than the axial length of the first planetary gear 29, and the outer diameter of the tooth tip of the first sun gear 28 is the large diameter shaft. The value is larger than the outer diameter of 27A. An end face 28A on one side in the axial direction of the first sun gear 28 is slidably contacted with a sliding member 39 described later, and an end face 28B on the other side in the axial direction is a sliding body of the rotary side housing 21. 21G is configured to slidably contact 21G.

  Reference numeral 29 denotes a plurality of first planetary gears that mesh with the first sun gear 28 and an internal gear 21 </ b> E provided on the inner peripheral side of the rotation-side housing 21. The first planetary gear 29 revolves while rotating around the first sun gear 28. For example, three first planetary gears 29 are provided around the first sun gear 28 (only one is shown). The outer diameter of the tooth tip of each first planetary gear 29 is formed to be larger than the dimension from the center to the outer diameter of the tooth tip of the first sun gear 28. The outer diameter side (tooth side) of the side end surface 29A faces first sun gear contact surfaces 40B1 and 41B1 of a sliding member 39 described later. Each first planetary gear 29 has an axial length L2 and meshes with the first sun gear 28 over the entire length of the axial length L2.

  Reference numeral 30 denotes a first carrier that rotatably supports each first planetary gear 29. The first carrier 30 has a disk shape smaller in diameter than the tip diameter of the internal gear 21E. The other side support plate 30A sandwiching the planetary gear 29 from the axial direction, the one side support plate 30B, and a plurality of connecting portions that connect between the other side support plate 30A and the one side support plate 30B and are spaced apart at equal intervals in the circumferential direction. 30C and a gear support shaft 30D that rotatably supports each first planetary gear 29 between the other side support plate 30A and the one side support plate 30B. In the first carrier 30, the other side support plate 30A, the one side support plate 30B, and the connecting portion 30C are integrally formed by, for example, casting.

  The other-side support plate 30A located on the other side in the axial direction is provided with a rotation shaft insertion hole 30A1 through which the rotation shaft 25 is inserted at the center thereof. For example, three other support shaft insertion holes 30A2 (only one is shown) are formed between the portions 30C. On one side support plate 30B located on one side in the axial direction, a female spline portion 30B1 that is spline-coupled to a second sun gear 33 described later is formed at the center thereof. Around the female spline portion 30B1, one side support shaft insertion hole 30B2 is formed at a position corresponding to each other side support shaft insertion hole 30A2 of the other side support plate 30A.

  The gear support shaft 30 </ b> D is supported at both ends by being inserted into the other support shaft insertion hole 30 </ b> A <b> 2 on the other side in the axial direction and inserted into the one side support shaft insertion hole 30 </ b> B <b> 2. The first planetary gears 29 are rotatably supported. The first carrier 30 rotatably supports each first planetary gear 29 by each gear support shaft 30 </ b> D, and each first planetary gear 29 rotates by revolving around the first sun gear 28. The rotation is transmitted to the planetary gear reduction mechanism 32 at the second stage.

  Reference numeral 32 denotes a second-stage planetary gear reduction mechanism disposed between the hydraulic motor 12 and the first-stage planetary gear reduction mechanism 24. The second-stage planetary gear reduction mechanism 32 is a first-stage planetary gear reduction mechanism 32. The rotation of the gear reduction mechanism 24 is decelerated and the rotation-side housing 21 is rotated. The second-stage planetary gear speed reduction mechanism 32 includes a second sun gear 33, a second planetary gear 36, a second carrier 37, and the like.

  Reference numeral 33 denotes a second sun gear disposed between the female spline portion 16A of the output shaft 16 and the first sun gear 28. The second sun gear 33 has a through hole 34 through which the rotary shaft 25 is inserted. It consists of the cylindrical body which has. The other side in the axial direction of the second sun gear 33 is connected to the female spline portion 30B1 of the first carrier 30, and one side in the axial direction meshes with a second planetary gear 36 described later.

  The end surface 33A on the other side in the axial direction of the second sun gear 33 located on the first sun gear 28 side is located in the first carrier 30 and faces the end surface 29A of the first planetary gear 29. . The second sun gear 33 is fixed to the first carrier 30 by a retaining ring 35 provided in the vicinity of the end surface 33A (one side position from the end surface 33A) on the outer peripheral side of the second sun gear 33. And is secured in the axial direction.

  In the through hole 34 of the second sun gear 33, a step 34A is provided at a position near the end surface 33A on the other side in the axial direction, that is, a position deeper than the end surface 33A and facing the first sun gear 28. Thereby, the step part 34A of the second sun gear 33 and the end face 28A of the first sun gear 28 face each other in the axial direction. And the through-hole 34 forms the male spline part 26 side as a small diameter hole part 34B over the full length rather than the step part 34A, and forms the 1st sun gear 28 side as a large diameter large diameter hole part 34C. . A sliding member 39, which will be described later, is disposed on the step portion 34A. The hole diameter of the small diameter hole 34B is slightly larger than the outer diameter of the male spline part 26 and the large diameter shaft 27A of the rotary shaft 25. On the other hand, the hole diameter of the large-diameter hole portion 34 </ b> C is formed to be larger than the outer diameter of the tooth tip of the first sun gear 28. Thereby, the end surface 28A side of the first sun gear 28 is configured to be accommodated in the large-diameter hole portion 34C.

  The cylindrical portion 21 </ b> A of the rotation-side housing 21 is filled with lubricating oil for smoothly driving the gears up to the vicinity of the axis of the rotation shaft 25. That is, the lower half of the gap S1 formed between the through hole 34 and the small diameter shaft 27B of the rotary shaft 25 is filled with a sufficient amount of lubricating oil. Thereby, the lubricating oil accumulated in the gap S1 can be caused to flow around the sliding member 39 described later, so that the lubricating state of the sliding member 39 can be kept good, and the first sun gear 28, The durability of the second sun gear 33 and the sliding member 39 can be improved.

  Reference numeral 36 denotes a plurality of second planetary gears that mesh with the second sun gear 33 and an internal gear 21 </ b> E provided on the inner peripheral side of the rotation-side housing 21. Each of the second planetary gears 36 rotates the rotation-side housing 21 by rotating around the second sun gear 33. For example, three second planetary gears 36 are provided around the second sun gear 33 ( Only one is shown). That is, each second planetary gear 36 rotates the rotation-side housing 21 with a large torque by decelerating the rotation transmitted from the first stage planetary gear reduction mechanism 24 to the second sun gear 33. is there.

  Reference numeral 37 denotes a second carrier which is attached to the stationary housing 19 in a non-rotating state and supports each second planetary gear 36 rotatably. The second carrier 37 has a disk shape slightly smaller than the diameter of the tip of the internal gear 21E. The other side support plate 37A and the one side support plate sandwich the second planetary gears 36 in the axial direction. 37B, between the other side support plate 37A and the one side support plate 37B, between the other side support plate 37A and the one side support plate 37B. A gear support shaft 37D that rotatably supports the second planetary gear 36 is configured. In the second carrier 37, the other side support plate 37A, the one side support plate 37B, and the connecting portion 37C are integrally formed by casting or the like, for example.

  The other side support plate 37A located on the other side in the axial direction is provided with a sun gear insertion hole 37A1 through which the second sun gear 33 is inserted at the center thereof, and around the sun gear insertion hole 37A1. For example, three other support shaft insertion holes 37A2 (only one is shown) are formed between the connecting portions 37C. The one side support plate 37B positioned on one side in the axial direction has a rotation shaft insertion hole 37B1 through which the rotation shaft 25 is inserted at the center thereof, and a female spline portion 37B2 that is splined to the male spline portion 19E of the fixed side housing 19. And are formed. Around the rotation shaft insertion hole 37B1, one side support shaft insertion hole 37B3 is formed at a position corresponding to each other side support shaft insertion hole 37A2 of the other side support plate 37A.

  The gear support shaft 37D is supported at both ends by being inserted into the other-side support shaft insertion hole 37A2 on the other side in the axial direction and inserted into the one-side support shaft insertion hole 37B3 on one side. The second planetary gears 36 are rotatably supported. The second carrier 37 is in a non-rotating state because the female spline portion 37B2 is spline-coupled to the male spline portion 19E of the stationary housing 19. Thus, the rotation of the output shaft 16 of the hydraulic motor 12 is decelerated by the first stage planetary gear reduction mechanism 24 and transmitted from the first stage planetary gear reduction mechanism 24 to the second sun gear 33, The speed is further reduced by the second planetary gear 36, and the rotation-side housing 21 is rotated with a large torque.

  39 is a sliding member provided between the 1st sun gear 28 and the 2nd sun gear 33, and this sliding member 39 has the same shape formed, for example with materials, such as a metal and resin. The first sun gear 28 and the second sun gear 33 are slidably in contact with each other in a state of being radially fitted to the outer peripheral side of the small-diameter shaft 27B of the rotary shaft 25. It is.

  Specifically, as shown in FIGS. 4 to 7, the sliding member 39 is combined in a cylindrical shape with the small-diameter shaft 27 </ b> B of the rotating shaft 25 interposed therebetween, and is inserted into the through hole 34 of the second sun gear. The first half bushing 40 and a second half bushing 41 having the same shape as the first half bushing 40 are configured. As a result, the small-diameter shaft 27B located between the large-diameter shaft 27A and the first sun gear 28 is formed into a stepped cylindrical shape by the first half bush 40 and the second half bush 41. The sliding member 39 can be fitted.

  The first half bush 40 includes a half cylinder portion 40A that extends in the axial direction in the small diameter hole portion 34B of the through hole 34 and a step portion 34A of the through hole 34 that faces the end surface 28 of the first sun gear 28. It is configured by a stepped portion 34 </ b> A and a semicircular arc-shaped flange portion 40 </ b> B that contacts the end surface 28 </ b> A of the first sun gear 28. The flange 40B is located on the back side of the first sun gear contact surface 40B1 on which the end surface 28A of the first sun gear 28 contacts, and the second sun gear. And a second sun gear contact surface 40B2 on which 33 step portions 34A abut. Here, as shown in FIG. 4, the axial length of the first half bushing 40 is L3.

  On the other hand, similarly to the first half bush 40, the second half bush 41 also includes a half cylinder portion 41A extending in the axial direction in the small diameter hole portion 34B of the through hole 34, and the first sun gear 28. It is comprised by the semicircular arc shaped collar part 41B extended in the radial direction outer side from the position of 34 A of step parts of the through-hole 34 which faces the end surface 28. As shown in FIG. The collar portion 41B has a first sun gear contact surface 41B1 on which the end surface 28A of the first sun gear 28 contacts, and a second sun gear contact surface 41B2 on which the step portion 34A of the second sun gear 33 contacts. And have. The axial length of the second half-bush 41 is L3.

  The first and second half bushes 40 and 41 are fitted on the outer peripheral side of the small-diameter shaft 27B so as to sandwich the small-diameter shaft 27B of the rotary shaft 25 from the radial direction. In this state, the rotary shaft 25 is inserted into the through hole 34 of the second sun gear 33 from the male spline part 26 side, whereby the half cylinder part 40A of the first and second half bushes 40, 41 is obtained. , 41A are fitted in the small diameter hole 34B of the second sun gear 33, and the flanges 40B, 41B of the first and second half bushes 40, 41 are the large diameter of the second sun gear 33. Arranged in the hole portion 34 </ b> C, the flange portions 40 </ b> B and 41 </ b> B of the first and second half bushes 40 and 41 engage with the step portion 34 </ b> A of the second sun gear 33. In this state, an annular gap 34D is formed between the outer peripheral surfaces 40B3 and 41B3 of the flange portions 40B and 41B and the inner peripheral surface 34C1 of the large-diameter hole portion 34C of the second sun gear 33 (see FIG. 5).

  Thus, the end surface 28A of the first sun gear 28 provided on the rotary shaft 25 and the stepped portion 34A of the second sun gear 33 are connected to the flange portions 40B of the first and second half bushes 40, 41, The first sun gear 28 and the rotary shaft 25 are configured to be axially positioned by the second sun gear 33, slidably abutting on 41B. Moreover, the half cylinder parts 40A and 41A of the first and second half bushes 40 and 41 are surrounded from the outer peripheral side by the small diameter hole part 34B of the second sun gear 33, and the flange parts 40B and 41B are The second sun gear 33 is surrounded by the large-diameter hole 34C from the outer peripheral side. As a result, when the hydraulic excavator 1 equipped with the reduction gear 18 is traveling, the first and second half bushes 40 and 41 are separated from the center of the rotary shaft 25 in the radial direction by the centrifugal force. It is configured to be suppressed by the through hole 34 of the sun gear 33.

  Here, as shown in FIG. 5, from the axial center line OO of the second sun gear 33 to the outer peripheral edges of the flanges 40 </ b> B and 41 </ b> B that are the outermost peripheries of the first and second half bushes 40 and 41. The length dimension A1 of the second sun gear 33 is configured to have a larger value (A1> A2) than the length dimension A2 from the axial center line OO of the second sun gear 33 to the tooth tip 29B of the first planetary gear 29. Yes.

  Further, the axial length dimension B1 of the half cylinder portions 40A, 41A constituting the first and second half bushes 40, 41 is the step portion 34A of the through hole 34 provided in the second sun gear 33. And a length dimension B2 between the first planetary gear 29 and the end face 29A on one axial side thereof (B1> B2).

  Therefore, as shown in FIG. 6, when the rotary shaft 25 is moved in the axial direction to disengage the first planetary gear 29 and the first sun gear 28, the first and second half bushes The flange portions 40 </ b> B and 41 </ b> B of 40 and 41 are engaged with the end surface 29 </ b> A of the first planetary gear 29. Accordingly, the first and second half bushes 40 and 41 are prevented from falling off the small diameter shaft 27B of the rotary shaft 25, and the small diameter shaft 27B is interposed between the first sun gear 28 and the second sun gear 33. It is the structure which can be made to fit in.

  On the other hand, the radial dimension R1 on the inner diameter side of the half cylinder portion 40A constituting the first half bush 40 and the half cylinder portion 41A constituting the second half bush 41 is the small diameter shaft 27B of the rotary shaft 25. It is formed to a value larger than the radial dimension R2. Therefore, between the small-diameter shaft 27B of the rotary shaft 25 and the inner peripheral surface 40C of the first half bush 40, and between the small-diameter shaft 27B of the rotary shaft 25 and the inner peripheral surface 41C of the second half bush 41. Each is provided with a radial gap S2. As a result, the first and second half bushes 40 and 41 and the small-diameter shaft 27B of the rotary shaft 25 are brought into a non-contact state, and the first and second half bushes 40 and 41 from the rotary shaft 25 are brought into contact with each other. It is the structure which can suppress that a big load acts.

  Furthermore, the half cylinder portions 40A and 41A of the first and second half bushes 40 and 41 are fitted into the small diameter hole portions 34B of the through holes 34 of the second sun gear 33, and each half cylinder portion 40A. , 41A and a small gap are provided between the outer peripheral surface of the small diameter hole portion 34B. As a result, even if the end surface 28A of the first sun gear 28 and the end surface 33A of the second sun gear 33 have a relative inclination due to, for example, manufacturing tolerances, the inclination is reduced to the first and second. It is configured to be able to absorb by a gap formed between the half cylinders 40A, 41A of the half bushes 40, 41 and the inner peripheral surface of the small diameter hole 34B of the second sun gear 33.

  On the other hand, on the second sun gear contact surface 40B2 side of the flange portion 40B of the first half bush 40, two substantially circular recessed portions 40D are provided at intervals in the circumferential direction. The recessed portion 40D communicates between the outer peripheral surface 40B3 of the flange 40B and the second sun gear contact surface 40B2. Further, in the flange portion 41B of the second half-bushing 41, on the second sun gear contact surface 41B2 side, there are two concave portions 41D having a substantially circular shape in the circumferential direction (only one is shown). ) Is provided. The recessed portion 41D communicates between the outer peripheral surface 41B3 of the flange portion 41B and the second sun gear contact surface 41B2. Thereby, the lubricating oil filled in the rotation side housing 21 is between the outer peripheral surfaces 40B3 and 41B3 of the flange portions 40B and 41B and the inner peripheral surface 34C1 of the large-diameter hole portion 34C of the second sun gear 33. The second sun gear contact surfaces 40B2 and 41B2 provided on the flanges 40B and 41B and the step 34A of the second sun gear 33 are introduced into the recessed portions 40D and 41D through the formed gap 34D. It is the structure supplied to a sliding part. In this case, since the lubricating oil ejected by the meshing of the first sun gear 28 and each first planetary gear 29 is introduced into the gap 34D, the second oil provided in each flange 40B, 41B. The sliding portion between the sun gear contact surfaces 40B2 and 41B2 and the step portion 34A of the second sun gear 33 can be efficiently lubricated.

  The speed reduction device 18 according to the present embodiment has the above-described configuration. When the output shaft 16 rotates when the hydraulic motor 12 is operated, the rotation of the output shaft 16 is performed via the rotation shaft 25 in the first stage. It is output to the first sun gear 28 constituting the planetary gear reduction mechanism 24. When the first sun gear 28 rotates, the first planetary gear 29 revolves while rotating around the first sun gear 28, and the revolution of the first planetary gear 29 is transmitted to the first carrier 30. The

  The decelerated rotation of the first carrier 30 is transmitted to the second sun gear 33 that constitutes the second stage planetary gear reduction mechanism 32, and the second planetary gear 36 that meshes with the second sun gear 33. However, it rotates while meshing with the internal gear 21 </ b> E of the rotation-side housing 21. Here, since the second carrier 37 supporting the second planetary gear 36 is splined to the stationary housing 19, the rotation of the second planetary gear 36 is rotated via the internal gear 21E. 21 is transmitted.

  Thus, the rotation of the hydraulic motor 12 is transmitted to the rotation-side housing 21 after being decelerated by two stages by the first-stage planetary gear reduction mechanism 24 and the second-stage planetary gear reduction mechanism 32. As a result, the rotation-side housing 21 to which the drive wheel 7 is fixed rotates with a large torque, and the crawler belt 8 wound around the idler wheel 6 and the drive wheel 7 is driven to rotate so that the hydraulic excavator 1 travels.

  In this case, flanges 40B and 41B of the first and second half bushes 40 and 41 are provided between the first sun gear 28 and the second sun gear 33 provided on the rotary shaft 25. The end surface 28A on the one side in the axial direction of the first sun gear 28 is in contact with the flanges 40B and 41B, and the end surface 28B on the other side in the axial direction is a slide provided on the rotation-side housing 21 (lid portion 21C). It contacts the moving body 21G. Thus, the first sun gear 28 and the second sun gear 33 can smoothly rotate relative to each other via the flanges 40B, 41B of the first and second half bushes 40, 41. Further, the first sun gear 28 and the rotary shaft 25 can be positioned in the axial direction between the first and second half bushes 40 and 41 and the sliding body 21G of the rotary housing 21.

  Here, the half cylinder portions 40A and 41A of the first and second half bushes 40 and 41 are surrounded from the outer peripheral side by the small diameter hole portion 34B of the second sun gear 33, and the flange portions 40B and 41B are The second sun gear 33 is surrounded by the large-diameter hole portion 34C from the outer peripheral side. Thereby, for example, the sliding body 21G is worn, and the first and second half bushes are rotated by the rotation of the rotation shaft 25 in a state where the rotation shaft 25 moves in the axial direction in the through hole 34 of the second sun gear 33. Even if a centrifugal force acts on 40, 41, the first and second half bushes 40, 41 are prevented from detaching from the center of the rotating shaft 25 in the radial direction, and the second sun gear 33 It can hold | maintain in the small diameter hole part 34B and the large diameter hole part 34C. As a result, even when the dimensional difference between the outer diameter of the male spline portion 26 of the rotating shaft 25 and the outer diameter of the first sun gear 28 is small, the first and second sun gears 28 and 33 are moved to the first sun gear 28 and 33. , Can be stably brought into contact with the flanges 40B and 41B of the second half bushes 40 and 41, and can smoothly rotate the first and second sun gears 28 and 33 over a long period of time. .

  In this case, between the inner peripheral surfaces 40C, 41C of the half cylinder portions 40A, 41A constituting the first and second half bushes 40, 41 and the outer peripheral surface of the small-diameter shaft 27B of the rotary shaft 25, A radial gap S2 is provided, and the first half bush 40, the second half bush 41, and the rotary shaft 25 are not in contact with each other. As a result, even when the shaft center of the rotary shaft 25 and the shaft center of the second sun gear 33 are misaligned during the operation of the reduction gear 18, the first and second half bushes 40, 41 and the first Since the contact with the second sun gear 33 can be suppressed and a large load can be suppressed from acting on the first and second half bushes 40 and 41 from the rotary shaft 25, the first and second The life of the half bushes 40 and 41 can be improved.

  Further, the first and second half bushes 40 and 41 are inserted into the half cylinder portions 40A and 41A inserted into the small diameter hole portion 34B of the second sun gear 33, and the step portion 34A of the second sun gear 33. It is comprised by the collar parts 40B and 41B engaged with. Thereby, since the hole diameter of the small diameter hole 34B through which the half cylinders 40A and 41A are inserted can be made as small as possible, the thickness from the outer peripheral side of the second sun gear 33 to the through hole 34 is increased. Can be (thick). As a result, even if a large torque acts on the second sun gear 33 from the first carrier 30, the torsional strength of the second sun gear 33 can be sufficiently secured, and the second sun gear 33. Can increase the durability.

  In addition, the first and second half bushes 40 and 41 can sufficiently secure a sliding surface with the first sun gear 28 by the flange portions 40B and 41B. Accordingly, the first sun gear 28 can smoothly rotate with respect to the flange portions 40B and 41B while being positioned in the axial direction by the first and second half bushes 40 and 41, and the speed is reduced. The reliability of the device 18 can be increased.

  Furthermore, the half cylinder portions 40A and 41A of the first and second half bushes 40 and 41 are fitted into the small diameter hole portions 34B of the through holes 34 of the second sun gear 33, and each half cylinder portion 40A. , 41A and a small gap are provided between the outer peripheral surface of the small diameter hole portion 34B. As a result, even if the end surface 28A of the first sun gear 28 and the end surface 33A of the second sun gear 33 have a relative inclination due to, for example, manufacturing tolerances, the inclination is reduced to the first and second. It can be absorbed by a gap formed between the half cylinders 40A, 41A of the half bushes 40, 41 and the inner peripheral surface of the small diameter hole 34B of the second sun gear 33. As a result, it is possible to prevent the flanges 40B and 41B of the first and second half bushes 40 and 41 from being unevenly worn due to sliding with the first sun gear 28. The life of the half bushes 40 and 41 can be improved.

  Here, the speed reduction device 18 according to the present embodiment can improve workability when the first-stage and second-stage planetary gear speed reduction mechanisms 24 and 32 are assembled in the rotation-side housing 21. Next, an assembly procedure for assembling the first stage planetary gear reduction mechanism 24 and the second stage planetary gear reduction mechanism 32 to the rotation-side housing 21 will be described.

  First, as shown in FIG. 12, a first assembly 42 including a rotary shaft 25, a first planetary gear 29, a first carrier 30, a second sun gear 33, and the like, a second planetary gear 36, After assembling the second assembly 43 including the second carrier 37 and the like separately, the first and second assemblies 42 and 43 are assembled into the stationary housing 19 and the rotation housing 21.

  When assembling the first assembly 42, as shown in FIGS. 8 and 9, the other axial side of the second sun gear 33 is splined to the female spline portion 30 B 1 of the first carrier 30. The second sun gear 33 is retained in the axial direction by the ring 35. Next, in the state where the first half bush 40 and the second half bush 41 are fitted from the radially outer side to the small diameter shaft 27B of the rotary shaft 25, the male spline portion 26 side of the rotary shaft 25 is provided. Is inserted into the rotary shaft insertion hole 30 </ b> A <b> 1 of the first carrier 30 and the through hole 34 of the second sun gear 33. Thereby, the half cylinder portions 40A and 41A of the first and second half bushes 40 and 41 are inserted into the small-diameter hole portion 34B of the through hole 34 (gap fit), and the first and second half bushes are inserted. The flange portions 40 </ b> B and 41 </ b> B of 40 and 41 are engaged with the step portion 34 </ b> A of the second sun gear 33.

  Next, as shown in FIG. 10, the first planetary gear 29 having the bearing 31 attached on the inner peripheral side is inserted between the other support plate 30A and the one support plate 30B of the first carrier 30. Then, the gear support shaft 30D is inserted into the other-side support shaft insertion hole 30A2, the bearing 31, and the one-side support shaft insertion hole 30B2 of the other-side support plate 30A, and is removed by the fixing pin 30D1. Stop. Thereby, as shown in FIG. 11, the 1st assembly 42 can be assembled.

  On the other hand, when assembling the second assembly 43, as shown in FIG. 12, the second planetary gear 36 having a bearing 38 attached to the inner peripheral side is connected to the other support plate 37A of the second carrier 37. The gear support shaft 37D is inserted between the side support plate 37B and the other side support plate 37A on the other side support shaft insertion hole 37A2, the bearing 38, and the one side support plate 37B on the one side support shaft insertion hole 37B3. Insert and fit with a fixing pin (not shown). Thereby, the second assembly 43 can be assembled.

  In order to assemble the first assembly 42 and the second assembly 43 thus assembled to the rotation-side housing 21, first, as shown in FIG. 12, the lid portion 21C of the rotation-side housing 21 is used. In a state in which the second assembly 43 is removed, the second assembly 43 is assembled to the rotation-side housing 21.

  Specifically, the second carrier 37 is inserted into the cylindrical portion 21 </ b> A of the rotation-side housing 21 with the second planetary gear 36 meshed with the internal gear 21 </ b> E of the rotation-side housing 21. Then, the female spline portion 37B2 of the second carrier 37 is splined to the male spline portion 19E of the fixed side housing 19, and the second carrier 37 is brought into contact with the bottom portion 19B of the fixed side housing 19. As a result, the second carrier 37 is attached to the stationary housing 19 in a non-rotating state while rotatably supporting the second planetary gear 36.

  Next, when the first assembly 42 is assembled to the rotation-side housing 21, the rotation shaft 25 is moved to the other side in the axial direction within the through hole 34 of the second sun gear 33 (see FIG. 13). Slide in the direction away from the output shaft 16. In this case, since the sliding member 39 can be slid toward the other side in the axial direction, the axial length dimension L1 of the small-diameter shaft 27B of the rotating shaft 25 is the axial direction of the first planetary gear 29. It is set to a value (L1> L2 + L3) larger than the total length dimension of the length dimension L2 and the axial length dimension L3 of the first and second half bushes 40, 41 constituting the sliding member 39. (See FIG. 4). Thereby, as shown in FIG. 13, the meshing of the first sun gear 28 and the first planetary gear 29 can be released.

  On the other hand, as shown in FIG. 5, from the axial center line OO of the second sun gear 33 to the outer peripheral edge (outermost periphery) of the flanges 40 </ b> B and 41 </ b> B of the first and second half bushes 40 and 41. The length dimension A1 is set to a value (A1> A2) larger than the length dimension A2 from the axial center line OO of the second sun gear 33 to the tooth tip 29B of the first planetary gear 29. . Further, the axial length dimension B1 of the half cylinder portions 40A, 41A constituting the first and second half bushes 40, 41 is the step portion 34A of the through hole 34 provided in the second sun gear 33. Is set to a value (B1> B2) larger than the length dimension B2 between the first planetary gear 29 and the end surface 29A on the one axial side of the first planetary gear 29.

  As a result, as shown in FIG. 6, even when the rotary shaft 25 is moved in the axial direction to disengage the first planetary gear 29 from the first sun gear 28, the first and second halves When the flanges 40B and 41B of the bushes 40 and 41 are hooked on the end surface 29A of the first planetary gear 29, the first and second half-bushings 40 and 41 drop off from the small diameter shaft 27B of the rotary shaft 25. Can be suppressed. Accordingly, the half cylinder portions 40A and 41A of the first and second half bushes 40 and 41 are held in the small diameter hole portion 34B of the second sun gear 33, and the first and second half bushes 40 are retained. , 41 can be fitted to the small-diameter shaft 27B between the first sun gear 28 and the second sun gear 33.

  In this way, with the first sun gear 28 and the first planetary gear 29 disengaged, the second sun gear 33 is inserted into the sun gear of the second carrier 37 as shown in FIG. By passing through the hole 37A1, the second sun gear 33 and the plurality (three) of the second planetary gears 36 are engaged with each other, and the plurality (three) of the first planetary gears 29 are engaged with the rotation side housing. 21 can be meshed with the internal gear 21E. In this case, since each first planetary gear 29 is not meshed with the first sun gear 28, it is in a freely rotatable state and can be easily meshed with the internal gear 21E.

  Next, as shown in FIG. 14, the first carrier 30, the first planetary gear 29, and the second sun gear 33 of the first assembly 42 are accommodated in the cylindrical portion 21 </ b> A of the rotation-side housing 21. In this case, the axial length dimension L1 of the small-diameter shaft 27B of the rotary shaft 25 is the same as the axial length dimension L3 of the first and second half bushes 40 and 41, and the female spline portion 16A of the output shaft 16 is rotated. It is set to a value (L1> L3 + L4) larger than the total length dimension of the axial length dimension L4 of the spline coupling part 26A with the male spline part 26 of the shaft 25 (see FIG. 4).

  As a result, when the first carrier 30, the first planetary gear 29, and the second sun gear 33 of the first assembly 42 are accommodated in the cylindrical portion 21A of the rotation side housing 21, the first sun gear 28 and the first planetary gear 29 can be disengaged, the male spline portion 26 of the rotating shaft 25 and the female spline portion 16A of the output shaft 16 can be disengaged, and the rotating shaft 25 is rotated independently. Can do.

  Accordingly, by sliding the rotary shaft 25 toward the output shaft 16 while rotating, the male spline portion 26 is engaged (spline coupled) with the female spline portion 16A of the output shaft 16 as shown in FIG. The first sun gear 28 can be engaged with the plurality of first planetary gears 29. Thus, by rotating the lightweight rotating shaft 25 independently, the male spline portion 26 and the female spline portion 16A of the output shaft 16, the first sun gear 28 and the first planetary gears 29 are meshed simultaneously. In addition, the phase of each tooth of the male spline portion 26 and the first sun gear 28 provided on the rotating shaft 25 can be finely adjusted. As a result, the engagement of the male spline portion 26 with the female spline portion 16A of the output shaft 16 and the engagement of the first sun gear 28 with each first planetary gear 29 can be easily performed.

  In this way, the female spline portion 16A of the output shaft 16 and the male spline portion 26 of the rotary shaft 25 are spline-coupled, and the first sun gear 28 is engaged with each first planetary gear 29. The lid portion 21C is fixed to the cylindrical portion 21A of the rotation side housing 21 with a bolt or the like. As a result, the first-stage and second-stage planetary gear speed reduction mechanisms 24 and 32 can be incorporated into the cylindrical portion 21A of the rotation-side housing 21, and the reduction gear 18 can be assembled.

  Here, for example, as in the comparative example shown in FIG. 16, when the axial length of the large diameter shaft 127A constituting the shaft portion 127 of the rotating shaft 125 is long and the axial length of the small diameter shaft 127B is short. If the rotary shaft 125 is slid in the direction away from the output shaft 116, the large-diameter shaft 127 </ b> A interferes with the first half bush 140 and the second half bush 141. Therefore, the rotating shaft 125 cannot be moved until the first sun gear 128 and the first planetary gear 129 are disengaged, and the first sun gear 128 and the first planetary gear of the rotating shaft 125 are not allowed to move. 129 always maintains a meshed state.

  Accordingly, when the first assembly including the rotation shaft 125 is assembled in the rotation side housing (not shown), the first sun gear 128 and the plurality of first planetary gears 129 are engaged with each other. The second sun gear 133 and the second planetary gear 136, the female spline portion 116A of the output shaft 116 and the male spline portion 126 of the rotating shaft 125, each first planetary gear 129 and the internal gear of the rotating side housing (not shown). 1), it is necessary to simultaneously mesh the teeth, and there is a problem that it takes time to adjust the meshing of these teeth.

  On the other hand, in the present embodiment, the axial length dimension L1 of the small-diameter shaft 27B of the rotary shaft 25 is equal to the axial length dimension L2 of the first planetary gear 29 and the first and second half bushes. It is set to a value (L1> L2 + L3) larger than the total length dimension of 40 and 41 in the axial length dimension L3 (see FIG. 4).

  As a result, the first assembly 42 constituted by the rotary shaft 25, the first planetary gear 29, the first carrier 30, the second sun gear 33, and the like is replaced with the second planetary gear 36, the second carrier. When the second assembly 43 made of 37 or the like is assembled in the rotation-side housing 21, the rotation shaft 25 is slid in the through hole 34 of the second sun gear 33 so that the first sun The meshing between the gear 28 and the first planetary gear 29 can be released. As a result, each of the first planetary gears 29 can be easily meshed with the internal gear 21E of the rotation-side housing 21 while the plurality of (three) first planetary gears 29 are rotatable, and the second sun gear The gear 33 and the plurality (three) of the second planetary gears 36 can be easily meshed with each other.

  In this case, since it is not necessary to adjust each tooth of each first planetary gear 29 and the internal gear 21E, and each tooth of the second sun gear 33 and each second planetary gear 36 at the same time, One planetary gear 29 can be meshed with the internal gear 21E, and workability when the second sun gear 33 is meshed with each second planetary gear 36 can be improved.

  In the present embodiment, the axial length L1 of the small-diameter shaft 27B of the rotary shaft 25 is set to the axial length L3 of the first and second half bushes 40 and 41 and the female of the output shaft 16. It is set to a value (L1> L3 + L4) larger than the total length dimension of the axial length dimension L4 of the spline coupling part 26A of the spline part 16A and the male spline part 26 of the rotating shaft 25 (see FIG. 4). .

  Accordingly, as shown in FIG. 14, the first carrier 30, the first planetary gear 29, and the second sun gear 33 of the first assembly 42 are accommodated in the cylindrical portion 21 </ b> A of the rotation-side housing 21. Thus, the meshing between the first sun gear 28 and the first planetary gear 29 and the meshing between the male spline portion 26 and the female spline portion 16A of the output shaft 16 can be released, and the rotating shaft 25 is rotated independently. be able to. As a result, by rotating the rotating shaft 25, the male spline portion 26 and the female spline portion 16A of the output shaft 16, the first sun gear 28 and the first planetary gears 29 are simultaneously meshed with each other. 26 and finely adjust the phase of each tooth of the first sun gear 28 to mesh the male spline portion 26 with the female spline portion 16A of the output shaft 16, and simultaneously turn the first sun gear 28 into each first planetary gear. 29 (see FIG. 15).

  Moreover, in the present embodiment, the length from the axial center line OO of the second sun gear 33 to the outer peripheral edge (outermost periphery) of the flanges 40B and 41B of the first and second half bushes 40 and 41. The length dimension A1 is set to a value (A1> A2) larger than the length dimension A2 from the axial center line OO of the second sun gear 33 to the tooth tip 29B of the first planetary gear 29. Further, the axial length dimension B1 of the half cylinder portions 40A, 41A constituting the first and second half bushes 40, 41 is set to the step portion 34A of the through hole 34 provided in the second sun gear 33. Is set to a value (B1> B2) larger than the length dimension B2 between the first planetary gear 29 and the end surface 29A on the one axial side of the first planetary gear 29.

  Thereby, even when the rotary shaft 25 is moved in the axial direction to disengage the first planetary gear 29 and the first sun gear 28, the flanges of the first and second half bushes 40, 41 40B and 41B engage with the first planetary gear 29 before the half cylinder portions 40A and 41A are extracted from the small diameter hole portion 34B of the second sun gear 33. Therefore, when the first sun gear 28 and the first planetary gear 29 are disengaged, the first and second half bushes 40 and 41 are inadvertently dropped from the small diameter shaft 27B of the rotary shaft 25. Can be prevented. As a result, the first and second half bushes 40 and 41 can be fitted to the small-diameter shaft 27B between the first sun gear 28 and the second sun gear 33, so that the speed reducer Workability when assembling 18 can be improved.

  Next, FIG. 17 and FIG. 18 show a second embodiment of the present invention, and the feature of the second embodiment is that the first and second half bushes constituting the sliding member have flanges. There is an uneven surface. In the second embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.

  In the figure, reference numeral 51 denotes a sliding member used in this embodiment in place of the sliding member 39 according to the first embodiment. The sliding member 51 includes the sliding member 39 according to the first embodiment. Similarly, it comprises a first half bush 52 and a second half bush 53 having the same shape.

  The first half bush 52 is radially outward from the position of the half cylinder portion 52A extending in the axial direction in the small diameter hole portion 34B of the through hole 34 of the second sun gear 33 and the step portion 34A of the through hole 34. And a semicircular arc-shaped flange portion 52 </ b> B extending in the direction. A radial gap S2 is provided between the inner peripheral surface 52C of the first half bush 52 and the small diameter shaft 27B of the rotary shaft 25, and the inner surface of the half cylindrical portion 52A and the small diameter hole portion 34B are provided inside. A slight gap is provided between the peripheral surface. The flange 52B is located on the first sun gear contact surface 52B1 with which the end surface 28A of the first sun gear 28 contacts, and on the back surface side of the first sun gear contact surface 52B1, and the second sun gear contact surface 52B1 It has the 2nd sun gear contact surface 52B2 with which the step part 34A of the sun gear 33 contact | abuts.

  Here, the first sun gear contact surface 52B1 of the flange portion 52B is provided with a plurality of groove-shaped recesses 52D that are recessed toward the second sun gear contact surface 52B2 so as to be spaced apart in the circumferential direction. Yes. That is, the first sun gear contact surface 52B1 is formed as an uneven surface by each recess 52D, and when the end surface 28A of the first sun gear 28 contacts the first sun gear contact surface 52B1, The contact friction between them (friction resistance) increases.

  Similarly to the first half bush 52, the second half bush 53 includes a half cylinder portion 53A and a flange portion 53B. A radial clearance S2 is provided between the inner peripheral surface 53C of the second half bushing 53 and the small diameter shaft 27B of the rotary shaft 25, and the inner surface of the outer peripheral surface of the half cylinder portion 53A and the small diameter hole portion 34B. A slight gap is provided between the peripheral surface. The flange portion 53B has a first sun gear contact surface 53B1 with which the end face 28A of the first sun gear 28 contacts, and a second sun gear contact with which the step portion 34A of the second sun gear 33 contacts. Surface 53B2.

  On the first sun gear contact surface 53B1 of the collar portion 53B, a plurality of groove-shaped recesses 53D are provided spaced apart in the circumferential direction. That is, the first sun gear contact surface 53B1 is formed as an uneven surface by the respective recesses 53D, and when the end surface 28A of the first sun gear 28 contacts the first sun gear contact surface 53B1, The contact friction between them (friction resistance) increases.

  The speed reduction device according to the second embodiment has the sliding member 51 as described above, and the basic operation is not different from that according to the first embodiment.

  Here, when the first sun gear 28 rotates during operation of the speed reducer, the flanges 52B and 53B of the first and second half bushes 52 and 53 are connected to the first sun gear 28 and the second sun gear. 33 is in sliding contact. In this case, the first sun gear contact surfaces 52B1 and 53B1 of the flange portions 52B and 53B are worn early by the end portions (edges) of the teeth of the first sun gear 28 being in sliding contact with each other. There is a fear.

  On the other hand, in the present embodiment, the first sun gear contact surface 52B1, on which the first sun gear 28 is slidably contacted, of the flange portions 52B, 53B of the first and second half bushes 52, 53. A plurality of recesses 52D and 53D are provided in 53B1. As a result, the frictional resistance between the first sun gear contact surfaces 52B1 and 53B1 of the first and second half bushes 52 and 53 and the end surface 28A of the first sun gear 28 is increased. The second half bushes 52 and 53 are driven by the first sun gear 28.

  For this reason, the first and second half bushes 52 and 53 actively slide with respect to the step portion 34A of the second sun gear 33 formed of a flat surface, and slide with the first sun gear 28. The movement is suppressed. As a result, the first and second half bushes 52 and 53 can be prevented from being worn early by the edges of the teeth of the first sun gear 28, and the first and second half bushes 52 and 53 The lifetime of 53 can be improved.

  Next, FIG. 19 and FIG. 20 show the third embodiment of the present invention, and the feature of the third embodiment is that the first half bush and the second half bush constituting the sliding member. And a chamfered part. Note that in the third embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.

  In the figure, reference numeral 61 denotes a sliding member used in the present embodiment in place of the sliding member 39 according to the first embodiment, and the sliding member 61 includes the sliding member 39 according to the first embodiment. Similarly, it comprises a first half bush 62 and a second half bush 63 having the same shape.

  The first half bush 62 is radially outward from the position of the half cylinder portion 62A extending in the axial direction in the small diameter hole portion 34B of the through hole 34 of the second sun gear 33 and the step portion 34A of the through hole 34. It is comprised by the semicircular arc shaped collar part 62B extended in this. A radial gap S2 is provided between the inner peripheral surface 62C of the first half bush 62 and the small diameter shaft 27B of the rotary shaft 25, and the inner surface of the half cylindrical portion 62A and the inner diameter of the small diameter hole portion 34B. A slight gap is provided between the peripheral surface. The flange portion 62B is located on the first sun gear contact surface 62B1 with which the end surface 28A of the first sun gear 28 contacts, and on the back surface side of the first sun gear contact surface 62B1, and the second sun gear contact surface 62B1. It has the 2nd sun gear contact surface 62B2 with which the step part 34A of the sun gear 33 contact | abuts.

  Here, between the inner peripheral surface 62C and the outer peripheral surface 62D of the first half-bushing 62, L is in contact with the second half-bushing 63 when combined with the second half-bushing 63. A character-shaped combination surface 62E is formed. The combination surface 62E includes a half cylinder part contact part 62E1 that contacts the half cylinder part 63A of the second half bush 63, and a collar part contact part that contacts the collar part 63B of the second half bush 63. Chamfered portion 62F is formed by cutting out the corner portion at a corner portion formed by 62E2 and intersecting flange contact portion 62E2 and first sun gear contact surface 62B1.

  Similarly to the first half bush 62, the second half bush 63 includes a half cylinder portion 63A and a flange portion 63B. A radial gap S2 is provided between the inner peripheral surface 63C of the second half-bush 63 and the small-diameter shaft 27B of the rotary shaft 25, and the inner surface of the half-cylindrical cylinder portion 63A and the small-diameter hole portion 34B. A slight gap is provided between the peripheral surface. In addition, the flange portion 63B is in contact with the first sun gear contact surface 63B1 with which the end surface 28A of the first sun gear 28 contacts, and with the second sun gear contact with which the step portion 34A of the second sun gear 33 contacts. Surface 63B2.

  Here, an L-shaped combination surface 63E is formed between the inner peripheral surface 63C and the outer peripheral surface 63D of the second half bush 63. The combination surface 63E includes a half cylinder portion contact portion 63E1 that contacts the half cylinder portion 63A of the second half bush 63, and a flange portion contact portion that contacts the collar portion 63B of the second half bush 63. A chamfered portion 63F is formed by cutting out the corner portion at the corner portion where the flange contact portion 63E2 and the first sun gear contact surface 63B1 intersect.

  The reduction gear according to the third embodiment has the sliding member 61 as described above, and the basic operation is not different from that according to the first embodiment.

  Here, when the first half bush 62 and the second half bush 63 are displaced in the axial direction, the combination of the flange portions 62B and 63B of the first and second half bushes 62 and 63 is achieved. When a level difference occurs in the portion, the edge of each tooth of the first sun gear 28 may be caught on this level difference.

  On the other hand, in the present embodiment, a chamfered portion 62F is provided at a corner portion where the combination surface 62E of the first half bushing 62 and the first sun gear contact surface 62B1 intersect, and the second half A chamfered portion 63F is provided at a corner where the combination surface 63E of the split bush 63 and the first sun gear contact surface 63B1 intersect.

  Thereby, even if the first and second half bushes 62 and 63 are displaced in the axial direction and a step is generated between the flanges 62B and 63B, the edges of the teeth of the first sun gear 28 are The chamfered portions 62F and 63F of the second half bushes 62 and 63 are smoothly contacted. Thereby, it can suppress that the edge of each tooth | gear of the 1st sun gear 28 is caught in the level | step difference between the collar parts 62B and 63B. As a result, the life of the first and second half bushes 62 and 63 can be improved, and the rotating shaft 25 (first sun gear 28) can be stably rotated.

  In the first embodiment described above, the first and second half bushes 40 and 41 constituting the sliding member 39 are sectioned by the half cylinder portions 40A and 41A and the flange portions 40B and 41B. The case where it forms in L shape is illustrated.

  However, the present invention is not limited to this, and for example, a sliding member 71 such as a modification shown in FIG. 21 may be formed. That is, the sliding member 71 includes a first half-bush 72 having a thick semi-cylindrical shape having no flange and a second half-bush having the same shape as the first half-bush 72. 73 may be used. In this case, the first and second half bushes 72 and 73 are fitted in the large-diameter hole portion 34C of the second sun gear 33 in a state where the first and second half bushes 72 and 73 are fitted to the small-diameter shaft 27B of the rotating shaft 25 from the radially outer side. A gap can be fitted.

  Further, in the first embodiment described above, the case where the first half bush 40 and the second half bush 41 are formed in the same shape is illustrated. However, the present invention is not limited to this. For example, the lengths in the axial direction of the half cylinder portions 40A and 41A of the first and second half bushes 40 and 41 may be different. There is no need. Further, the dividing surfaces of the first and second half bushes 40 and 41 are not necessarily flat.

  Moreover, in 2nd Embodiment mentioned above, the case where recessed part 52D, 53D is formed in 1st sun gear contact surface 52B1, 53B1 of 1st, 2nd half-split bush 52,53 is illustrated. . However, the present invention is not limited to this. For example, the first sun gear contact surface may be provided with a convex portion that fits into the tooth groove portion of the end surface of the first sun gear. In addition, a sheet for increasing the surface roughness may be attached to the first sun gear contact surface or may be processed.

  Furthermore, in each embodiment mentioned above, the case where the reduction gear 18 was used for the traveling device 11 of the excavator 1 was described as an example. However, the present invention is not limited to this, and can be widely applied to, for example, a traveling device for other construction machines such as a hydraulic crane, a winch device for winding a rope, and the like.

11 Traveling device 12 Hydraulic motor (rotation source)
16 Output shaft 16A Female spline portion 18 Reduction gear 19 Fixed housing 21 Rotation side housing 21E Internal gear 24 First stage planetary gear reduction mechanism 25 Rotating shaft 26 Male spline portion 26A Spline coupling portion 27 Shaft portion 27A Large diameter shaft 27B Small diameter Shaft 28 First sun gear 28A End face 29 First planetary gear 29A End face 29B Tooth tip 30 First carrier 32 Second stage planetary gear reduction mechanism 33 Second sun gear 33A End face 34 Through hole 34A Step part 34B Small diameter Hole portion 34C Large diameter hole portion 36 Second planetary gear 37 Second carrier 39, 51, 61, 71 Sliding member 40, 52, 62, 72 First half bushing 40A, 41A, 52A, 53A, 62A , 63A Half cylinder part 40B, 41B, 52B, 53B, 62B, 63B collar part 40B1, 41B1, 5 2B1, 53B1, 62B1, 63B1 First sun gear contact surface 40B2, 41B2, 52B2, 53B2, 62B2, 63B2 Second sun gear contact surface 40C, 41C, 52C, 53C, 62C, 63C Inner peripheral surface 52D, 53D Concave part 41, 53, 63, 73 2nd half bushing 62E, 63E Combination surface 62F, 63F Chamfer

Claims (5)

A stationary housing housing a rotation source having an output shaft provided with a female spline portion; a rotation housing provided rotatably with respect to the stationary housing; and driven by the rotation source; And a first stage planetary gear reduction mechanism disposed between the rotation source and the first stage planetary gear reduction mechanism. Comprising a second stage planetary gear reduction mechanism that reduces the rotation of the rotation side and rotates the rotation side housing,
The first stage planetary gear speed reduction mechanism is provided with a male spline portion that extends in the axial direction in the rotary housing and is splined to the female spline portion of the output shaft on one side in the axial direction. Meshed with the rotation shaft, the first sun gear provided on the other side in the axial direction of the rotation shaft, the first sun gear and the internal gear provided on the inner peripheral side of the rotation side housing; A plurality of first planetary gears that revolve around the first sun gear and a first carrier that rotatably supports the first planetary gears;
The second stage planetary gear speed reduction mechanism is formed of a cylindrical body having a through hole through which the rotation shaft is inserted, and is disposed between the female spline portion of the output shaft and the first sun gear. The second sun gear connected to the first carrier, and the second sun gear and an internal gear provided on the inner peripheral side of the rotation side housing mesh with each other and rotate around the second sun gear. And a plurality of second planetary gears that rotate the rotation-side housing, and a second carrier that is attached to the fixed-side housing in a non-rotating state and rotatably supports the second planetary gears. and,
The rotation shaft of the first stage planetary gear speed reduction mechanism is such that the male spline portion side is large between the male spline portion on one side in the axial direction and the first sun gear on the other side in the axial direction. In the speed reducer formed as a stepped shaft that becomes a radial axis and the first sun gear side becomes a small-diameter axis,
Between the first sun gear and the second sun gear, two halves are fitted on the outer peripheral side of the small-diameter shaft of the rotating shaft, and the first sun gear and the first sun gear. A sliding member that slidably contacts with the sun gear of 2;
The through hole of the second sun gear is provided with a step portion at a position facing the first sun gear, and the first sun gear side is formed as a large-diameter hole portion having a larger diameter than the step portion. The sliding member is arranged in the large-diameter hole of the second sun gear ,
The axial length dimension (L1) of the small-diameter shaft of the rotating shaft is the sum of the axial length dimension (L2) of the first planetary gear and the axial length dimension (L3) of the sliding member. Configured to a value larger than the length dimension (L1> L2 + L3),
The length dimension A1 from the axial center line of the second sun gear to the outermost periphery of the sliding member is the length from the axial center line of the second sun gear to the tooth tip of the first planetary gear. A value larger than the dimension A2 (A1> A2),
The axial length dimension (L1) of the small-diameter shaft of the rotating shaft includes the axial length dimension (L3) of the sliding member, the female spline portion of the output shaft, and the male spline portion of the rotating shaft. A reduction device characterized in that the spline coupling portion is configured to have a value (L1> L3 + L4) larger than the total length dimension with the axial length dimension (L4) . The sliding member includes a first half bush and a second half bush which are combined in a cylindrical shape with a small-diameter shaft of the rotating shaft interposed therebetween and inserted into the through hole of the second sun gear. Configure
And the radial dimension of the inner diameter side of the first half bush, and the radial dimension of the inner diameter side of the second half bush is formed to a larger value than the radius of the small diameter shaft,
Wherein said small-diameter shaft of the rotary shaft first, between the second half inner circumferential surface of the bush, the deceleration device according to claim 1 comprising as Tei Ru configuration provided radial gap. Through hole of the second sun gear, together than the step portion forming the male spline portion as small-diameter hole portion over the entire length, it forms the first sun gear side as the large diameter hole portion ,
The first and second half bushes include a half cylinder portion extending in the axial direction in the small diameter hole portion of the through hole, and the step portion and the first portion extending radially outward from the position of the step portion. And a flange that contacts the end face of the sun gear,
The axial length dimension B1 of the half cylinder part is a value larger than the length dimension B2 between the step part of the second sun gear and the end surface on one axial side of the first planetary gear ( The speed reducer according to claim 2 , wherein the speed reducer is configured as B1> B2). The flange portions of the first and second half bushes are located on the first sun gear contact surface with which the first sun gear contacts, and on the back side of the first sun gear contact surface. A second sun gear contact surface with which the step portion of the second sun gear contacts,
The speed reducer according to claim 3 , wherein the first sun gear contact surface is formed as an uneven surface that increases contact friction with the first sun gear. The flange portions of the first and second half bushes are located on the first sun gear contact surface with which the first sun gear contacts, and on the back side of the first sun gear contact surface. A second sun gear contact surface with which the step portion of the second sun gear contacts,
A chamfered portion is formed by cutting out the corner portion at the corner portion where the combination surface when the first and second half bushings are combined and the first sun gear contact surface. reduction gear transmission according to claim 3 comprising as Tei Ru configuration provided.

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