Speed reduction device

Abstract

To make it possible to restrain wear of a thrust plate by integrally rotating a first sun gear and the thrust plate.SOLUTION: A speed reduction device comprises a thrust plate 25 located between a first sun gear 18 and a first carrier 21, and provided around a rotating shaft 17. The thrust plate 25 comprises: an engagement part 25E located on the side of the first sun gear 18, and engaged with teeth 18A of the first sun gear 18 in a rotation direction; and a sliding contact surface 25F located on the side opposite to the first sun gear 18, and in sliding contact with the first carrier 21.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a speed reducer suitably used for a traveling device of construction machines such as hydraulic excavators, hydraulic cranes, wheel loaders, dump trucks, etc.

Background Art

[0002] Generally, the lower traveling body of a crawler-type construction machine such as a hydraulic excavator includes a track frame having left and right side frames, a traveling device provided on one side in the longitudinal direction of the left and right side frames, a drive wheel (sprocket) provided on the traveling device, an idler wheel provided on the other side in the longitudinal direction of each side frame, and a crawler wound around the drive wheel and the idler wheel.

[0003] The traveling device of a hydraulic excavator usually consists of a hydraulic motor serving as a rotation source and a speed reducer that decelerates and outputs the rotation of the hydraulic motor. This speed reducer includes a fixed-side housing that houses the hydraulic motor, a rotation-side housing that is rotatably provided with respect to the fixed-side housing and is driven by the hydraulic motor, and a planetary gear speed reduction mechanism that is housed in the rotation-side housing and decelerates the rotation of the hydraulic motor.

[0004] The planetary gear speed reduction mechanism includes a rotating shaft that extends axially in the rotation-side housing and has one side in the axial direction coupled to the output shaft of the hydraulic motor, a first sun gear provided on the other side in the axial direction of the rotating shaft, and a plurality of first planetary gears that revolve around the first sun gear while rotating by meshing with the first sun gear and an internal gear provided on the inner peripheral side of the rotation-side housing, and a first carrier that rotatably supports the plurality of first planetary gears.

[0005] Also, a thrust plate that regulates the axial positions of the first sun gear and the first carrier is provided between the first sun gear and the first carrier. The thrust plate is provided around the rotating shaft (Patent Document 1).

Prior Art Documents

Patent Documents

[0006] Patent Document 1 Japanese Patent Application Laid-Open No. 2019-167045 Summary of the Invention Problems to be Solved by the Invention

[0007] By the way, in the invention of Patent Document 1, since the end face of the teeth provided around the first sun gear and the thrust plate are in sliding contact in the rotational direction, there is a problem that the thrust plate wears due to the sliding contact in the rotational direction.

[0008] The present invention has been made in view of the problems of the above-described prior art, and an object of the present invention is to provide a speed reduction device capable of suppressing wear of the thrust plate by integrally rotating the first sun gear and the thrust plate. Means for Solving the Problems

[0009] The present invention includes a fixed-side housing that houses a rotation source, a rotation-side housing that is rotatably provided with respect to the fixed-side housing and is driven by the rotation source, and a planetary gear reduction mechanism that is housed in the rotation-side housing and reduces the rotation of the rotation source. The planetary gear reduction mechanism includes a rotating shaft that extends axially in the rotation-side housing and has one axial side coupled to the output shaft of the rotation source, a first sun gear provided on the other axial side of the rotating shaft, and a plurality of first planetary gears that revolve around the first sun gear while rotating by meshing with the first sun gear and an internal gear provided on the inner peripheral side of the rotation-side housing. The planetary gear reduction mechanism further includes a first carrier that rotatably supports the plurality of first planetary gears, and a thrust plate that is positioned between the first sun gear and the first carrier and is provided around the rotating shaft. In the reduction device, the thrust plate includes an engaging portion that is positioned on the first sun gear side and engages with the teeth of the first sun gear in the rotation direction, and a sliding contact surface that is positioned on the side opposite to the first sun gear and slidably contacts the first carrier.

Advantages of the Invention

[0010] According to an embodiment of the present invention, the first sun gear and the thrust plate can be integrally rotated, and wear of the thrust plate can be suppressed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Mode for Carrying Out the Invention

[0012] Hereinafter, taking the case where the speed reduction device according to the embodiment of the present invention is applied to the traveling device of a crawler-type hydraulic excavator as a construction machine as an example, it will be described in detail with reference to the accompanying drawings.

[0013] Figures 1 to 6 show a first embodiment of the present invention. In Figure 1, the body of the hydraulic excavator 1 is composed of a crawler-type lower traveling body 2 capable of self-propulsion and an upper revolving body 3 rotatably mounted on the lower traveling body 2. A working device 4 is rotatably provided on the front side of the upper revolving body 3. The hydraulic excavator 1 performs earthwork operations by rotating the working device 4 while rotating the upper revolving body 3.

[0014] The lower traveling body 2 includes a truck frame 5 having left and right side frames 5A (only the left side is shown) extending in the front-rear direction, a traveling device 8 described later provided on one longitudinal side of the left and right side frames 5A, a floating wheel 6 provided on the other longitudinal side of the left and right side frames 5A, and a crawler 7 wound around the floating wheel 6 and a driving wheel 14 described later provided on the traveling device 8.

[0015] The traveling device 8 includes a traveling device bracket 9 fixed to one longitudinal side of the left and right side frames 5A, a hydraulic motor 10 as a rotation source attached to the traveling device bracket 9 via a fixed-side housing 12 described later, and a speed reduction device 11 described later that reduces the rotation of the output shaft 10A of the hydraulic motor 10. The traveling device 8 reduces the rotation of the hydraulic motor 10 by the speed reduction device 11 to rotate the driving wheel 14 with a large torque, and circulates the crawler 7 wound around the driving wheel 14 and the floating wheel 6.

[0016] Although the hydraulic motor 10 is configured to be attached to the fixed-side housing 12 described later as a separate member, in the embodiment, the hydraulic motor 10 and the fixed-side housing 12 are integrally shown for simplicity of explanation.

[0017] Next, the configuration and operation of each part of the speed reduction device 11, which is a characteristic part of the present invention, will be described in detail.

[0018] The speed reduction device 11 reduces the rotation speed of the hydraulic motor 10 and transmits it to the drive wheels 14. As shown in Fig. 2, the speed reduction device 11 includes a fixed-side housing 12, a rotating-side housing 13, a planetary gear speed reduction mechanism 16, and a thrust plate 25, which will be described later. Further, the speed reduction device 11 has an axis O-O that serves as the center of rotation of the rotating-side housing 13 and the like.

[0019] The fixed-side housing 12 is fixedly provided on the traveling device brackets 9 of the left and right side frames 5A. The fixed-side housing 12 is formed in a bottomed cylindrical shape, and the hydraulic motor 10 is attached to one side in the axial direction (the direction of the axis O-O). An annular flange portion 12A is provided at one side position on the outer peripheral side of the fixed-side housing 12, and this flange portion 12A is fixed to the traveling device bracket 9 using bolts or the like.

[0020] Also, a male spline portion 12B formed of an involute spline is provided at the other side position on the outer peripheral side of the fixed-side housing 12, and a female spline portion 24D of a second carrier 24, which will be described later, is spline-coupled to this male spline portion 12B. On the other hand, the output shaft 10A of the hydraulic motor 10 and a rotating shaft 17, which will be described later, are inserted through the center of the fixed-side housing 12.

[0021] The rotating-side housing 13 is arranged to surround the outer periphery of the fixed-side housing 12 and is rotatably provided with respect to the fixed-side housing 12. The rotating-side housing 13 is driven by the hydraulic motor 10. The rotating-side housing 13 is formed as a cylindrical body with a flange, which is composed of a cylindrical portion 13A and a flange portion 13B integrally formed on the outer periphery of one side in the axial direction of the cylindrical portion 13A. The open end located on the other side in the axial direction of the cylindrical portion 13A is closed by a lid portion 13C. A drive wheel 14 formed of a sprocket is attached to the flange portion 13B of the rotating-side housing 13 using bolts or the like.

[0022] An internal gear 13D is formed over the entire circumference at the other side position in the axial direction of the inner peripheral surface of the cylindrical portion 13A. This internal gear 13D meshes with a first planetary gear 20 and a second planetary gear 23, which will be described later.

[0023] The bearing 15 is provided between the outer peripheral surface of the fixed-side housing 12 and the inner peripheral surface of the cylindrical portion 13A of the rotating-side housing 13. The two bearings 15 rotatably support the rotating-side housing 13 with respect to the fixed-side housing 12.

[0024] The planetary gear reduction mechanism 16 is housed within the rotating-side housing 13 and reduces the rotation of the output shaft 10A of the hydraulic motor 10. The planetary gear reduction mechanism 16 includes a rotating shaft 17, a first sun gear 18, a first planetary gear 20, a first carrier 21, a second sun gear 22, a second planetary gear 23, a second carrier 24, and a thrust plate 25.

[0025] The planetary gear reduction mechanism 16 performs reduction in multiple stages (illustrated by the case of two stages in the embodiment). The first sun gear 18, the first planetary gear 20, and the first carrier 21 form the first-stage reduction mechanism, and the second sun gear 22, the second planetary gear 23, and the second carrier 24 form the second-stage reduction mechanism.

[0026] The rotating shaft 17 is disposed to extend axially within the cylindrical portion 13A of the rotating-side housing 13. Also, one axial side of the rotating shaft 17 is spline-coupled to the output shaft 10A of the hydraulic motor 10. That is, the rotating shaft 17 is disposed coaxially with the output shaft 10A of the hydraulic motor 10 and rotates integrally with the output shaft 10A of the hydraulic motor 10. A first sun gear 18, which will be described later, is provided on the other axial side of the rotating shaft 17.

[0027] The first sun gear 18 is integrally formed on the other axial side of the rotating shaft 17. The first sun gear 18 rotates integrally with the output shaft 10A of the hydraulic motor 10 and the rotating shaft 17. The first sun gear 18 includes a plurality of teeth 18A that are continuous in the circumferential direction, and the plurality of teeth 18A are formed in a tapered trapezoidal shape where the base end side is wide and the tip end side is narrow. Also, as shown in FIG. 3, one axial end portion of the plurality of teeth 18A that faces the thrust plate 25 described later forms an engaging tooth portion 18A1 that engages with the engaging portion 25E of the thrust plate 25. Furthermore, grooves are formed between the plurality of teeth 18A.

[0028] The first sun gear 18 has the end face on the other side in the axial direction slidably contacting a sliding contact body 19 provided at the inner center of the lid portion 13C of the rotating housing 13. Thereby, the first sun gear 18 is axially positioned by being restricted from moving to the other side in the axial direction by the sliding contact body 19.

[0029] As shown in FIGS. 2 and 3, a plurality (only one is shown in the figure) of the first planetary gears 20 are provided between the first sun gear 18 and the internal gear 13D of the rotating housing 13. The first planetary gear 20 is rotatably supported by the support shaft 21C of the first carrier 21. Thereby, the first planetary gear 20 rotates while meshing with the first sun gear 18 and the internal gear 13D, and revolves around the first sun gear 18.

[0030] The first carrier 21 is rotatably provided on the inner peripheral side of the rotating housing 13 and rotatably supports a plurality of the first planetary gears 20. The first carrier 21 includes a disk-shaped substrate 21B having a female spline portion 21A formed of an involute spline at the central portion, and a plurality (only one is shown in the figure) of support shafts 21C protruding from the end face of the substrate 21B so as to surround the periphery of the female spline portion 21A. The female spline portion 21A is spline-coupled to the male spline portion 22B of the second sun gear 22 described later. A plurality of the first planetary gears 20 are rotatably supported by the plurality of support shafts 21C.

[0031] On the other side in the axial direction of the substrate 21B, a stepped portion 21D is formed by expanding the other end portion of the female spline portion 21A. The stepped portion 21D has an annular bottom surface 21D1 having a larger diameter than the tooth bottom of the female spline portion 21A, and an inner peripheral surface 21D2 extending to the other side from the periphery of the bottom surface 21D1. The bottom surface 21D1 is a surface with which the sliding contact surface 25F of the thrust plate 25 described later slidably contacts.

[0032] Furthermore, a relief portion 21E is formed at the other end of the female spline portion 21A. The relief portion 21E is formed in a tapered shape by inclining the other end face of the female spline portion 21A from the tooth root to the tooth tip toward one side. Thereby, the relief portion 21E can prevent the thrust plate 25 and the female spline portion 21A from coming into contact with each other.

[0033] In the first-stage reduction mechanism of the planetary gear reduction mechanism 16, a plurality of first planetary gears 20 rotatably supported by the first carrier 21 revolve around the first sun gear 18 to rotate, and this rotation is transmitted to the second-stage reduction mechanism of the planetary gear reduction mechanism 16.

[0034] The second sun gear 22 constituting the second-stage reduction mechanism of the planetary gear reduction mechanism 16 is formed of a cylindrical body through which the rotary shaft 17 is inserted. Specifically, the second sun gear 22 is formed of a cylindrical body having an inner diameter dimension slightly larger than that of the rotary shaft 17, and is disposed between the output shaft 10A of the hydraulic motor 10 and the first sun gear 18. A plurality of teeth 22A continuous in the circumferential direction are provided on the outer peripheral side of the second sun gear 22. Further, a male spline portion 22B formed of an involute spline is formed on the outer periphery of the other axial side (the first sun gear 18 side) of the second sun gear 22. The male spline portion 22B is spline-coupled to the female spline portion 21A of the first carrier 21. Thereby, the second sun gear 22 rotates integrally with the first carrier 21. A thrust plate 25 described later is provided between the second sun gear 22 and the first sun gear 18.

[0035] A plurality of (only one is shown in the figure) second planetary gears 23 are provided between the internal gear 13D of the rotary housing 13 and the second sun gear 22. The plurality of second planetary gears 23 are rotatably supported by the support shaft 24C of the second carrier 24. Further, the second planetary gears 23 are engaged with the internal gear 13D and the teeth 22A of the second sun gear 22. Therefore, when the second sun gear 22 rotates integrally with the first carrier 21 and the second planetary gears 23 rotate around the second sun gear 22, the rotary housing 13 rotates.

[0036] As a result, the rotation of the output shaft 10A of the hydraulic motor 10 is decelerated in two stages by the planetary gear reduction mechanism 16, and the rotating housing 13 (drive wheel 14) can be rotated with a large torque.

[0037] The second carrier 24 is attached to the fixed housing 12 in a non-rotating state and rotatably supports a plurality of second planetary gears 23. The second carrier 24 includes a disk-shaped substrate 24A located around the rotating shaft 17 and facing the other end surface of the fixed housing 12, a mounting cylinder portion 24B extending from the periphery of the substrate 24A toward the outer peripheral side of the fixed housing 12, and a plurality of (only one is shown in the figure) support shafts 24C protruding from the substrate 24A to the other side so as to surround the rotating shaft 17.

[0038] On the inner peripheral surface of the mounting cylinder portion 24B, a female spline portion 24D formed of an involute spline that is spline-coupled to the male spline portion 12B of the fixed housing 12 is formed. Further, a plurality of support shafts 24C rotatably support the second planetary gears 23.

[0039] And since the second carrier 24 spline-couples the female spline portion 24D to the male spline portion 12B of the fixed housing 12, it is in a non-rotating state with respect to the fixed housing 12. As a result, the rotation of the output shaft 10A of the hydraulic motor 10 is transmitted from the first carrier 21 to the second sun gear 22 and then further decelerated by the second planetary gears 23, and the rotating housing 13 is rotated with a large torque.

[0040] The thrust plate 25 according to the first embodiment is provided around the rotating shaft 17 and is located between the first sun gear 18 and the first carrier 21. The thrust plate 25 defines (positions) the axial position of the first sun gear 18 with respect to the first carrier 21 (first planetary gear 20) and is formed as an annular plate body.

[0041] As shown in FIGS. 3 and 4, the outer diameter dimension of the thrust plate 25 is set to be larger than the root of the female spline portion 21A of the first carrier 21 and slightly smaller than the inner peripheral surface 21D2 of the stepped portion 21D. Thereby, the outer peripheral side (outside the root of the female spline portion 21A) of one end surface 25A of the thrust plate 25 serves as a sliding contact surface 25F with the bottom surface 21D1 of the stepped portion 21D.

[0042] On the other hand, the inner diameter dimension of the thrust plate 25 is set to be larger than the base end (tooth root) of the tooth 18A of the first sun gear 18 and smaller than the tip (tooth tip). In other words, the inner diameter dimension of the thrust plate 25 is set to be equal to the inner diameter dimension of the second sun gear 22. Thereby, the inner peripheral side of the thrust plate 25 overlaps the tooth 18A of the first sun gear 18 so as to be engageable.

[0043] The thrust plate 25 includes one end surface 25A on the second sun gear 22 side, the other end surface 25B on the first sun gear 18 side, an outer peripheral surface 25C, and an inner peripheral surface 25D. Furthermore, the thrust plate 25 has an engaging portion 25E that is located on the first sun gear 18 side (the other end surface 25B side) and engages with the tooth 18A of the first sun gear 18 in the rotational direction, a sliding contact surface 25F that is located on the one end surface 25A side opposite to the first sun gear 18 and slides in contact with the first carrier 21, and a non-contact surface 25G that is located on the inner peripheral side of the sliding contact surface 25F. The non-contact surface 25G is always separated so as not to contact the female spline portion 21A of the first carrier 21 and the male spline portion 22B of the second sun gear 22.

[0044] The engaging portion 25E according to the first embodiment is disposed on the inner peripheral side that overlaps the tooth 18A of the first sun gear 18 in the axial direction, and is formed to be recessed from the other end surface 25B by about half of the plate thickness dimension as shown in FIG. 5. Thereby, even when the first sun gear 18 and the first carrier 21 are most separated in the axial direction, the engaging portion 25E can always be engaged with the tooth 18A of the first sun gear 18.

[0045] As shown in Fig. 6, the engaging portion 25E is formed radially in a circumferential arrangement corresponding to the number of teeth of the teeth 18A of the first sun gear 18. That is, the engaging portion 25E is formed by a plurality of trapezoidal recesses 25E1 as engaging recesses having a tapered shape similar to that of the tooth 18A so that the teeth 18A of the first sun gear 18 can fit one by one. Further, the trapezoidal recess 25E1 is formed slightly larger than the engaging tooth portion 18A1 of the tooth 18A, so that it can engage with the first sun gear 18 without play.

[0046] In the first embodiment, the case where 12 trapezoidal recesses 25E1 of the engaging portion 25E are provided is illustrated. That is, 12 teeth 18A of the first sun gear 18 are also provided, the same number as the trapezoidal recesses 25E1. However, the number of teeth of the first sun gear and the number of trapezoidal recesses of the engaging portion may be other than 12.

[0047] The thrust plate 25 is located around the rotating shaft 17 and provided between the first sun gear 18 and the first carrier 21. In this mounted state, the trapezoidal recesses 25E1 of the engaging portion 25E on the inner peripheral side of the thrust plate 25 are engaged so as to fit into the engaging tooth portions 18A1 of the teeth 18A of the first sun gear 18. Further, on the thrust plate 25, the sliding contact surface 25F on the outer peripheral side of one end surface 25A abuts against the bottom surface 21D1 of the stepped portion 21D of the first carrier 21. Furthermore, on one end surface 25A of the thrust plate 25, the non-contact surface 25G other than the sliding contact surface 25F is separated from the female spline portion 21A of the first carrier 21 and the male spline portion 22B of the second sun gear 22.

[0048] As a result, since the thrust plate 25 rotates integrally with the first sun gear 18, the sliding contact portion of the thrust plate 25 is only the sliding contact surface 25F with the bottom surface 21D1 of the stepped portion 21D of the first carrier 21.

[0049] The traveling device 8 equipped with the speed reducer 11 according to the first embodiment has the configuration as described above. When the hydraulic motor 10 operates and the output shaft 10A rotates, the rotation of the output shaft 10A is output to the first sun gear 18 that constitutes the first-stage speed reduction mechanism via the rotating shaft 17. When the first sun gear 18 rotates, the first planetary gear 20 meshing with the internal gear 13D of the rotating housing 13 and the first sun gear 18 revolves around the first sun gear 18 while rotating on its own axis. The revolution of the first planetary gear 20 is transmitted to the first carrier 21.

[0050] The decelerated rotation of the first carrier 21 is transmitted to the second sun gear 22 that constitutes the second-stage speed reduction mechanism, and the second planetary gear 23 meshing with the second sun gear 22 rotates on its own axis while meshing with the internal gear 13D of the rotating housing 13. The rotation of the second planetary gear 23 is transmitted to the rotating housing 13 via the internal gear 13D.

[0051] In this way, the rotation of the hydraulic motor 10 is decelerated in two stages by the speed reducer 11 and then transmitted to the rotating housing 13. As a result, the drive wheel 14 fixed to the rotating housing 13 rotates with a large torque, and the crawler belt 7 wound around the drive wheel 14 and the idler wheel 6 is driven to circulate, causing the hydraulic excavator 1 to travel.

[0052] Here, when the speed reducer 11 operates, the rotating first sun gear 18 and the first carrier 21 may move in the axial direction. In contrast, the thrust plate 25 is disposed between the first sun gear 18 and the first carrier 21 and abuts on both of them in the axial direction, thereby positioning the first sun gear 18 and the first carrier 21 in the axial direction.

[0053] However, the thrust plate according to the prior art is in sliding contact with both the first sun gear and the first carrier. For this reason, the sliding contact portions where wear occurs are at two locations, namely, between the thrust plate and the first sun gear and between the thrust plate and the first carrier, so there is a risk of increased wear of the thrust plate.

[0054] However, the speed reducer 11 according to the first embodiment includes a thrust plate 25 provided around the rotary shaft 17 and positioned between the first sun gear 18 and the first carrier 21. This thrust plate 25 includes an engaging portion 25E that is positioned on the first sun gear 18 side and engages with the teeth 18A of the first sun gear 18 in the rotational direction, and a sliding contact surface 25F that is positioned on the side opposite to the first sun gear 18 and is in sliding contact with the first carrier 21.

[0055] Therefore, since the thrust plate 25 according to the first embodiment rotates integrally with the first sun gear 18, the sliding contact portion of the thrust plate 25 can be only at one location between the sliding contact surface 25F of the thrust plate 25 and the bottom surface 21D1 of the stepped portion 21D of the first carrier 21. Moreover, contact between the teeth 18A of the first sun gear 18, which are likely to wear, and the thrust plate 25 can be avoided. As a result, wear of the thrust plate 25 can be suppressed, and durability can be improved.

[0056] The speed reducer 11 according to the first embodiment includes a second sun gear 22 that is formed of a cylindrical body through which the rotary shaft 17 is inserted and is disposed between the output shaft 10A of the hydraulic motor 10 and the first sun gear 18. Further, on the inner peripheral side of the first carrier 21, a female spline portion 21A that is spline-coupled to the teeth 22A of the second sun gear 22 is provided. Additionally, a relief portion 21E for avoiding contact between the female spline portion 21A of the first carrier 21 and the thrust plate 25 is provided on the female spline portion 21A of the first carrier 21. Thereby, the relief portion 21E can suppress wear of the thrust plate 25 caused by the female spline portion 21A slidingly contacting one end surface 25A of the thrust plate 25.

[0057] Furthermore, the engaging portion 25E of the thrust plate 25 is composed of a plurality of trapezoidal recesses 25E1 as engaging recesses into which the teeth 18A of the first sun gear 18 are fitted. As shown in FIG. 6, the trapezoidal recesses 25E1 have a tapered shape similar to that of the teeth 18A so that the engaging tooth portions 18A1 of the teeth 18A of the first sun gear 18 are fitted one by one. Thereby, the trapezoidal recesses 25E1 as the engaging recesses can engage with all the teeth 18A of the first sun gear 18 without play.

[0058] Next, FIGS. 7 and 8 show a second embodiment of the present invention. The feature of the second embodiment is that a plurality of teeth provided on the first sun gear are divided into a plurality of circumferential sections, and the engaging portion of the thrust plate is formed as a plurality of fan-shaped recesses in which a plurality of teeth in one section are respectively received. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0059] In FIG. 7, a thrust plate 31 according to the second embodiment is provided around the rotation axis 17 between the first sun gear 18 and the first carrier 21, similarly to the thrust plate 25 according to the first embodiment, and includes an end face 31A, an opposite end face 31B, an outer peripheral face 31C, an inner peripheral face 31D, an engaging portion 31E, a sliding contact face 31F, and a non-contact face 31G. The engaging portion 31E according to the second embodiment is recessed from the opposite end face 31B by about half of the plate thickness dimension.

[0060] Also, in the second embodiment, after dividing a plurality of teeth 18A provided on the first sun gear 18 into a plurality of circumferential sections, the engaging portion 31E of the thrust plate 31 is formed as a plurality of fan-shaped recesses 31E1 as engaging recesses in which a plurality of teeth 18A in one section are respectively received.

[0061] Specifically, twelve teeth 18A provided on the first sun gear 18 are divided into a plurality of circumferential sections, for example, into four sections with three adjacent teeth 18A as a set. Then, as shown in FIG. 8, the fan-shaped recesses 31E1 of the engaging portion 31E are formed in a fan shape in which three adjacent teeth 18A are received.

[0062] In the second embodiment, the case where the three teeth 18A are accommodated in the fan-shaped concave portion 31E1 of the engaging portion 31E is illustrated. However, the fan-shaped concave portion can also be formed so that two or four or more teeth can be accommodated therein.

[0063] Thus, also in the second embodiment configured as described above, substantially the same operational effects as those of the first embodiment described above can be obtained. In particular, according to the second embodiment, since the number of the fan-shaped concave portions 31E1 provided in the thrust plate 31 can be reduced, the manufacturing cost of the thrust plate 31 can be suppressed low.

[0064] Next, FIGS. 9 and 10 show a third embodiment of the present invention. The feature of the third embodiment is that the engaging portion of the thrust plate is an engaging convex portion that engages with all the grooves between the teeth of the first sun gear. In the third embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof is omitted.

[0065] In FIG. 9, a thrust plate 41 according to the third embodiment is provided around the rotation shaft 17 between the first sun gear 18 and the first carrier 21 in the same manner as the thrust plate 25 according to the first embodiment, and includes a first end surface 41A, a second end surface 41B, an outer peripheral surface 41C, an inner peripheral surface 41D, an engaging portion 41E, a sliding contact surface 41F, and a non-contact surface 41G. However, the thrust plate 41 according to the third embodiment is different from the thrust plate 25 according to the first embodiment in the following configuration.

[0066] First, the plate thickness dimension (the distance dimension between the first end surface 41A and the second end surface 41B) of the thrust plate 41 is set to about half of that of the thrust plate 25 of the first embodiment. Further, the engaging portion 41E is formed by a triangular convex portion 41E1 as an engaging convex portion that engages with the grooves between the teeth 18A of the first sun gear 18 (see FIG. 10).

[0067] Specifically, the triangular convex portions 41E1 are formed as 12 triangular protrusions so as to fit into the triangular grooves formed between the 12 teeth 18A respectively. The height dimension (protrusion dimension) of the triangular convex portions 41E1 is set to be equal to the plate thickness dimension of the thrust plate 41. Thereby, the triangular convex portions 41E1 forming the engaging portion 41E can always engage with the engaging tooth portions 18A1 of the teeth 18A in the circumferential direction.

[0068] Thus, also in the third embodiment configured as described above, substantially the same operational effects as those of the first embodiment described above can be obtained. In particular, according to the third embodiment, the plate thickness dimension of the thrust plate 41 can be made thinner, and the thrust plate 41 can be lightened.

[0069] Next, FIGS. 11 and 12 show a fourth embodiment of the present invention. The feature of the fourth embodiment is that the engaging portion of the thrust plate is an engaging convex portion that engages with a groove between the teeth of the first sun gear with an interval. In the fourth embodiment, the same reference numerals are given to the same components as those in the third embodiment, and the description thereof is omitted.

[0070] In FIG. 11, the thrust plate 51 according to the fourth embodiment is located between the first sun gear 18 and the first carrier 21 and provided around the rotation axis 17 in the same manner as the thrust plate 41 according to the third embodiment, and includes one end face 51A, the other end face 51B, the outer peripheral face 51C, the inner peripheral face 51D, the engaging portion 51E, the sliding contact face 51F, and the non-contact face 51G. However, the configuration of the engaging portion 51E of the thrust plate 51 according to the fourth embodiment is different from that of the thrust plate 41 according to the third embodiment.

[0071] The engaging portion 51E according to the fourth embodiment is formed by a triangular convex portion 51E1 as an engaging convex portion that engages with the groove between the teeth 18A of the first sun gear 18 (see FIG. 12). Specifically, the triangular convex portion 51E1 is formed as a triangular protrusion that fits into three grooves in the circumferential direction sandwiching four teeth 18A among the twelve triangular grooves formed between the twelve teeth 18A. The height dimension (protrusion dimension) of the triangular convex portion 51E1 is set to be equal to the plate thickness dimension of the thrust plate 51. Thereby, the three triangular convex portions 51E1 forming the engaging portion 51E can always engage with the engaging tooth portion 18A1 of the tooth 18A in the circumferential direction.

[0072] In the fourth embodiment, the case where three triangular convex portions 51E1 of the engaging portion 51E are provided so as to fit into three of the twelve grooves formed between the twelve teeth 18A is illustrated. However, two, four to eleven triangular convex portions can also be provided.

[0073] Thus, even in the fourth embodiment configured as described above, substantially the same operational effects as those of the third embodiment described above can be obtained. In particular, according to the fourth embodiment, since the number of the triangular convex portions 51E1 of the engaging portion 51E can be reduced, weight reduction and reduction of manufacturing costs can be achieved.

[0074] Next, FIGS. 13 and 14 show the fifth embodiment of the present invention. The feature of the fifth embodiment is that the engaging portion of the thrust plate is a square convex portion that engages with the groove between the teeth of the first sun gear with a gap. In the fifth embodiment, the same components as those in the fourth embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0075] In FIG. 13, the thrust plate 61 according to the fifth embodiment is located between the first sun gear 18 and the first carrier 21 and provided around the rotation axis 17, similar to the thrust plate 51 according to the fourth embodiment, and includes a first end face 61A, a second end face 61B, an outer peripheral face 61C, an inner peripheral face 61D, an engaging portion 61E, a sliding contact face 61F, and a non-contact face 61G. However, the engaging portion 61E of the thrust plate 61 according to the fifth embodiment is different from that of the thrust plate 51 according to the fourth embodiment in configuration.

[0076] The engaging portion 61E according to the fifth embodiment is formed by a square convex portion 61E1 as an engaging convex portion that engages with a groove between the teeth 18A of the first sun gear 18 (see FIG. 14). Specifically, the square convex portion 61E1 is formed as a square (rectangular parallelepiped) protrusion that fits into three grooves in the circumferential direction sandwiching four teeth 18A out of the twelve grooves formed between the twelve teeth 18A. The height dimension (protrusion dimension) of the square convex portion 61E1 is set to be equal to the plate thickness dimension of the thrust plate 61. Thereby, the three square convex portions 61E1 forming the engaging portion 61E can always engage with the engaging tooth portions 18A1 of the teeth 18A in the circumferential direction.

[0077] In the fifth embodiment, the case where three square convex portions 61E1 of the engaging portion 61E are provided so as to fit into three of the twelve grooves formed between the twelve teeth 18A is illustrated. However, two, four to eleven square convex portions can also be provided.

[0078] Thus, even in the fifth embodiment configured as described above, substantially the same operational effects as those of the fourth embodiment described above can be obtained.

[0079] Next, FIGS. 15 and 16 show the sixth embodiment of the present invention. The feature of the sixth embodiment is that a relief portion for avoiding contact between the thrust plate and the female spline of the second sun gear is provided on the thrust plate. In the sixth embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof is omitted.

[0080] First, in the sixth embodiment, since a relief portion 71H is provided in the thrust plate 71 described later, a relief portion 21E is not provided in the first carrier 21.

[0081] In FIG. 15, the thrust plate 71 according to the sixth embodiment is located between the first sun gear 18 and the first carrier 21 and provided around the rotation axis 17, similar to the thrust plate 25 according to the first embodiment, and includes a first end face 71A, a second end face 71B, an outer peripheral face 71C, an inner peripheral face 71D, an engaging portion 71E (trapezoidal recess 71E1), a sliding contact face 71F, and a non-contact face 71G. The thrust plate 71 according to the sixth embodiment is different from the thrust plate 25 according to the first embodiment in terms of the formation position of the non-contact face 71G.

[0082] The thrust plate 71 has a relief portion 71H formed of an annular step by recessing the inner peripheral side more than the sliding contact face 71F, specifically, from the bottom of the teeth of the female spline portion 21A to the inner peripheral side (see FIG. 16). The bottom face of this relief portion 71H serves as the non-contact face 71G. The relief portion 71H (non-contact face 71G) can avoid contact between the thrust plate 25 and the female spline portion 21A.

[0083] Thus, even in the sixth embodiment configured as described above, substantially the same operational effects as those of the first embodiment described above can be obtained. In particular, according to the sixth embodiment, since the relief portion 71H is provided in the thrust plate 71, the relief portion 71H can be provided more easily compared to the case where the relief portion 21E is provided in the first carrier 21.

[0084] Next, FIG. 17 shows a seventh embodiment of the present invention. The feature of the seventh embodiment is that it includes a second sun gear formed of a cylindrical body through which the rotation axis is inserted and arranged between the output shaft of the rotation source and the first sun gear, and the second sun gear has its second end face abutted against the thrust plate. In the seventh embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof is omitted.

[0085] In FIG. 17, the second sun gear 81 according to the seventh embodiment is formed of a cylindrical body through which the rotating shaft 17 is inserted, similar to the second sun gear 22 according to the first embodiment, and is disposed between the output shaft 10A of the hydraulic motor 10 and the first sun gear 18. A plurality of teeth 81A continuous in the circumferential direction are formed on the outer peripheral side of the second sun gear 81, and a male spline portion 81B is formed on the outer periphery of the other axial side (the first sun gear 18 side) of the second sun gear 81.

[0086] Further, the second sun gear 81 is formed to be longer than the second sun gear 22 according to the first embodiment, and the other end surface thereof is a contact surface 81C that contacts one end surface 25A of the thrust plate 25.

[0087] Thus, even in the seventh embodiment configured as described above, substantially the same operational effects as those of the first embodiment described above can be obtained.

[0088] In the first embodiment, the case where the male spline portions 12B and 22B, the female spline portions 21A and 24D, etc. are formed as involute splines is illustrated. However, the present invention is not limited to this, and for example, each spline portion may be formed as another spline such as a square spline. This configuration can be similarly applied to other embodiments.

[0089] In the embodiment, the case where the speed reduction device 11 is applied to the traveling device 8 of the hydraulic excavator 1 is illustrated. However, the present invention is not limited to this, and for example, the speed reduction device may be applied to the traveling devices of hydraulic cranes, wheel loaders, dump trucks, etc. This configuration can be similarly applied to other embodiments.

Explanation of Reference Numerals

[0090] 10 Hydraulic motor (rotation source) 10A Output shaft 11 Speed reduction device 12 Fixed-side housing 13 Rotating-side housing 13D Internal gear 16 Planetary gear reduction mechanism 17 Rotating shaft 18 First sun gear 18A, 22A, 81A Teeth 20 First planetary gear 21 First carrier 21A Female spline part 21E, 71H Relief part 22, 81 Second sun gear 22B Male spline part 25, 31, 41, 51, 61, 71 Thrust plate 25E, 31E, 41E, 51E, 61E, 71E Engaging part 25E1, 71E1 Trapezoidal recess (engaging recess) 25F, 31F, 41F, 51F, 61F, 71F Sliding contact surface 31E1 Sector-shaped recess (engaging recess) 41E1, 51E1 Triangular convex part (engaging convex part) 61E1 Square convex part (engaging convex part) 81C Contact surface

Claims

1. A fixed-side housing that houses a rotation source, A rotation-side housing that is rotatably provided with respect to the fixed-side housing and is driven by the rotation source, A planetary gear reduction mechanism that is housed in the rotation-side housing and reduces the rotation of the rotation source, comprising The planetary gear reduction mechanism A rotating shaft that extends axially in the rotation-side housing and has one axial side coupled to the output shaft of the rotation source, A first sun gear provided on the other axial side of the rotating shaft, A plurality of first planetary gears that revolve around the first sun gear while rotating by meshing with the first sun gear and an internal gear provided on the inner peripheral side of the rotation-side housing, A first carrier that rotatably supports the plurality of first planetary gears, A thrust plate provided around the rotating shaft and positioned between the first sun gear and the first carrier, In a reduction device comprising The thrust plate An engaging portion that is located on the first sun gear side and engages with the teeth of the first sun gear in the rotation direction, A sliding contact surface that is located on the side opposite to the first sun gear and is in sliding contact with the first carrier, A reduction device, characterized in that it comprises

2. In the reduction device according to Claim 1, It comprises a second sun gear that is formed of a cylindrical body through which the rotating shaft is inserted and is arranged between the output shaft and the first sun gear, An internal spline that is spline-coupled to the teeth of the second sun gear is provided on the inner peripheral side of the first carrier, A reduction device, characterized in that at least one of the thrust plate and the internal spline of the first carrier is provided with a relief portion for avoiding contact between the thrust plate and the internal spline.

3. In the speed reduction device according to claim 1, It comprises a cylindrical body through which the rotating shaft is inserted and a second sun gear disposed between the output shaft and the first sun gear, The speed reduction device, wherein the other end face of the second sun gear is in contact with the thrust plate.

4. In the speed reduction device according to claim 1, The speed reduction device, wherein the engaging portion of the thrust plate is an engaging recess into which the teeth of the first sun gear fit.

5. In the speed reduction device according to claim 1, The speed reduction device, wherein the engaging portion of the thrust plate is an engaging convex portion that engages with the groove between the teeth of the first sun gear.

Images