Shaft member, planetary gear unit and planetary gear device

Abstract

To provide a shaft member, a planetary gear unit and a planetary gear device that promote discharge of foreign matter to stably form an oil film on a sliding portion, thereby reducing seizure and abnormal wear and prolonging a service life.SOLUTION: An outer peripheral surface 27 of a shaft member 22 slides against an inner peripheral surface 24 of a planetary gear member 21. The shaft member 22 comprises a sliding part 26, an opening part 41, a connection passage part 42, and a groove part 43. The sliding part 22 is provided on the outer peripheral side of a body part 25, and has an outer peripheral surface 27 that slides against the inner peripheral surface 24. The outer peripheral surface 27 is divided circumferentially into a first region 31 and a second region 32 set in advance. The opening part 41 opens into the first region 31 on the outer peripheral side of the sliding part 26. The groove part 43 is recessed radially inward from the outer peripheral surface 27, and connects the opening part 41 to at least one axial end part of the sliding part 26. A groove end part 48, which is an end part opposite the opening part 41, opens to an outer wall 29 at an axial end part of the sliding part 26.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present embodiment relates to a shaft member, a planetary gear unit, and a planetary gear device. [Background technology]

[0002] A planetary gear device is provided between a power input side and an output side, and transmits the driving force of the input side to the output side by either speeding up or slowing down. This planetary gear device is equipped with a planetary gear unit that revolves in the circumferential direction between a so-called sun gear and an internal gear while meshing with them. The planetary gear unit has a planetary gear member with external teeth and a shaft member that rotates relatively inside the planetary gear member.

[0003] In recent years, while devices that generate driving force have become larger, there has been a demand for further weight reduction in planetary gear devices. Therefore, the use of plain bearings, instead of conventional rolling bearings, for support between the planetary gear members and the shaft members in planetary gear devices has been considered. While the use of plain bearings allows for the miniaturization of planetary gear devices, it also increases torque density, which increases the load on the sliding parts.

[0004] This type of planetary gear device has a unique configuration in which the area where a large load is applied between the planetary gear members of the planetary gear unit and the shaft member that supports it is limited during operation of the planetary gear device. In other words, the inner circumferential surface of the planetary gear members and the outer circumferential surface of the shaft member that slide against each other always form areas where a relatively large load is applied and areas where a relatively small load is applied within specific ranges, regardless of changes in position due to rotation.

[0005] Therefore, lubrication between the planetary gear member and the shaft member is an important factor for a planetary gear unit. Patent Document 1 provides concave and convex portions on the sliding portions between the planetary gear member and the shaft member. This promotes retention of lubricating oil in the concave portions, and promotes the formation of an oil film in areas where large local loads are applied depending on the operating conditions, even when a sliding bearing is used.

[0006] However, in the case of Patent Document 1, foreign matter that penetrates between the planetary gear member and the shaft member tends to remain in the recesses, hindering the formation of an oil film at the sliding portion. In particular, when using a plain bearing, it is necessary to prevent foreign matter from penetrating between the inner circumferential surface of the planetary gear member and the outer circumferential surface of the shaft member, which form the sliding portion, in order to maintain an oil film of lubricating oil. Penetration of foreign matter causes scratches on the sliding portion, which in turn hinders the formation of an oil film at the sliding portion. As a result, problems such as seizure and abnormal wear occur at the sliding portion between the planetary gear member and the shaft member. Furthermore, in the case of Patent Document 1, grooves that supply lubricating oil to the sliding portion are provided around the entire circumference, including areas where the load is high. Therefore, in Patent Document 1, the overall sliding area is reduced, leading to an increase in oil film pressure, and there is a risk of oil film formation being hindered due to insufficient supply of lubricating oil at the axial end portions and the penetration of foreign matter into areas where the load is high. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. WO2021 / 058262 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, the present embodiment aims to provide a shaft member, planetary gear unit, and planetary gear device that have a long lifespan by promoting the discharge of foreign matter and forming a stable oil film in the sliding parts, thereby reducing seizure and abnormal wear. [Means for solving the problem]

[0009] In order to solve the above problems, the shaft member of this embodiment is a shaft member that slides against the inner peripheral surface of the planetary gear member and includes a sliding portion, an opening, a connecting passage portion, and a groove portion. The sliding portion is provided on the outer peripheral side of the main body portion and has an outer peripheral surface that slides against the inner peripheral surface, and the outer peripheral surface is divided circumferentially into a predetermined first region and a second region other than the first region. The opening opens into the first region on the outer peripheral side of the sliding portion. The connecting passage portion connects at least one axial end of the shaft member to the opening. The groove portion is recessed radially inward from the outer peripheral surface and connects the opening to at least one axial end of the sliding portion, and the groove end, which is the end opposite the opening, opens to the outer wall at the axial end of the sliding portion.

[0010] As a result, in this embodiment, the lubricating oil is supplied to the opening via the connecting passage portion, and then from the opening through the groove portion to the sliding portion between the inner circumferential surface and the outer circumferential surface. The lubricating oil that flows out of the opening passes through the groove portion and is discharged from the groove end. As a result, even if foreign matter enters the sliding portion between the inner circumferential surface and the outer circumferential surface, the foreign matter is facilitated to be discharged from the groove end along with the lubricating oil via the groove portion. Furthermore, in this embodiment, the opening opens into a first region, which is a predetermined region. Therefore, when configuring a planetary gear unit together with the planetary gear member, by adjusting the first region to a region where the load applied during sliding is relatively small, an oil film can be stably formed in the required portion between the inner circumferential surface and the outer circumferential surface. Therefore, it is possible to promote the discharge of foreign matter, and also to form a stable oil film in the sliding parts, thereby reducing seizure and abnormal wear, thereby extending the lifespan. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic perspective view showing an example of the configuration of a planetary gear device; [Figure 2] 1 is a schematic diagram showing a cross section along an axis of a planetary gear unit according to an embodiment; [Figure 3] Schematic diagram seen from the direction of arrow III in Figure 2 [Figure 4]4 is a schematic view of the shaft member according to the first embodiment, as viewed in the direction of arrow IV in FIG. [Figure 5] FIG. 1 is a schematic view showing an outer peripheral surface of a shaft member according to a first embodiment, developed in the circumferential direction; [Figure 6] FIG. 10 is a schematic perspective view showing a second region set on the outer circumferential surface of the shaft member according to the first embodiment; [Figure 7] Schematic diagram showing a shaft member according to a first embodiment. [Figure 8] Schematic diagram showing a modified example of the shaft member according to the first embodiment. [Figure 9] Schematic diagram showing a modified example of the shaft member according to the first embodiment. [Figure 10] Schematic diagram showing a shaft member according to a second embodiment. [Figure 11] 10 is a schematic diagram showing a modified example of the shaft member according to the second embodiment; [Figure 12] 10 is a schematic diagram showing a modified example of the shaft member according to the second embodiment; [Figure 13] FIG. 10 is a schematic view showing a shaft member according to a third embodiment; [Figure 14] 11 is a schematic diagram showing a modified example of the shaft member according to the third embodiment; [Figure 15] 11 is a schematic diagram showing a modified example of the shaft member according to the third embodiment; [Figure 16] FIG. 10 is an enlarged schematic view of the vicinity of a throttled portion in order to show the shape of the throttled portion in a shaft member according to a third embodiment; [Figure 17] FIG. 11 is a schematic diagram showing the relationship between the groove portion and the throttle portion in the shaft member according to the third embodiment; [Figure 18] FIG. 10 is a schematic view showing a shaft member according to a fourth embodiment; [Figure 19] FIG. 11 is a schematic view showing a modified example of the shaft member according to the fourth embodiment; [Figure 20] FIG. 11 is a schematic view showing a modified example of the shaft member according to the fourth embodiment; [Figure 21] FIG. 11 is a schematic view showing a modified example of the shaft member according to the fourth embodiment; [Figure 22] FIG. 11 is a schematic view showing a modified example of the shaft member according to the fourth embodiment; [Figure 23] FIG. 11 is a schematic view showing a modified example of the shaft member according to the fourth embodiment; [Figure 24]FIG. 11 is a schematic view showing a modified example of the shaft member according to the fourth embodiment; [Figure 25] Schematic diagrams showing examples of shaft members according to other embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments will be described with reference to the drawings. In multiple embodiments, substantially identical components are denoted by the same reference numerals, and descriptions thereof will be omitted. In this specification, the axial direction is the direction parallel to the rotating axis as shown by A-A' in FIG. 1, the radial direction is the direction perpendicular to this axial direction, and the circumferential direction is the circumferential direction centered on the axis as shown by R-R' in FIG. 1.

[0013] (planetary gear unit) FIG. 1 shows an example of a typical planetary gear device 10. The planetary gear device 10 includes a first shaft member 11, a second shaft member 12, a sun gear 13, an internal gear 14, a carrier 15, and a planetary gear unit 16. For simplicity, the gear members in FIG. 1 and other figures are not shown with their teeth. The sun gear 13 is attached to the first shaft member 11 and rotates integrally with the first shaft member 11. The sun gear 13 is a so-called external gear and has external teeth 17 on its outer periphery. The internal gear 14 is a so-called internal gear and is formed in an annular shape with internal teeth 18 on its inner periphery. The carrier 15 is attached to the second shaft member 12 and rotates integrally with the second shaft member 12.

[0014] The planetary gear unit 16 has a planetary gear member 21 and a shaft member 22. The planetary gear member 21 is an external gear and is supported by the shaft member 22 so as to be capable of relative rotation. The planetary gear unit 16 is provided between the sun gear 13 and the internal gear 14, and is in mesh with both the sun gear 13 and the internal gear 14. One or more planetary gear units 16 are provided in the circumferential direction of the sun gear 13. The shaft member 22 of the planetary gear unit 16 is supported by the carrier 15.

[0015] As a result, when the carrier 15 rotates together with the second shaft member 12 as an input shaft, this rotation is transmitted to the planetary gear unit 16. For example, by fixing the internal gear 14 so that it cannot rotate, the planetary gear unit 16 revolves around the sun gear 13. At this time, the planetary gear member 21 of the planetary gear unit 16 and the shaft member 22 supported by the carrier 15 rotate relative to each other. In other words, the planetary gear member 21 rotates in the opposite direction to the revolution of the carrier 15 due to the revolution of the carrier 15. For example, if the revolution direction of the carrier 15 is clockwise, the rotation direction of the planetary gear member 21 is counterclockwise. Therefore, as the shaft member 22 fixed to the carrier 15 rotates together with the carrier 15, the planetary gear member 21 and the shaft member 22 rotate relative to each other. As a result, the inner peripheral side of the planetary gear member 21 and the outer peripheral side of the shaft member 22 slide against each other. When the planetary gear unit 16 revolves, rotation is transmitted to the first shaft member 11 as an output shaft via the sun gear 13. As a result, the rotation input from the second shaft member 12 is accelerated by the planetary gear device 10 and transmitted to the first shaft member 11. In the above example, the second shaft member 12 is the input side, the first shaft member 11 is the output side, and the internal gear 14 is fixed, thereby increasing the speed. However, the planetary gear device 10 can be arbitrarily combined with any one of the three elements, the first shaft member 11, the second shaft member 12, and the internal gear 14, as the input side, any one element as the output side, and the remaining element as a fixed element.

[0016] (planetary gear unit) The planetary gear unit 16 used in the planetary gear device 10 will now be described. The planetary gear unit 16 of this embodiment includes the planetary gear member 21 and the shaft member 22 as described above. As shown in FIGS. 2 and 3 , the planetary gear member 21 is an external gear with an external tooth portion 23 provided on its outer periphery, and is formed in a cylindrical shape. The planetary gear member 21 has a cylindrical inner circumferential surface 24. The shaft member 22 is provided on the inner circumferential side of the cylindrical planetary gear member 21. The planetary gear member 21 and the shaft member 22 rotate relative to each other. Therefore, the outermost surface of the shaft member 22 slides against the inner circumferential surface 24 of the planetary gear member 21.

[0017] (First embodiment of shaft member) As shown in FIG. 2 , the shaft member 22 according to the first embodiment has a main body portion 25 and a sliding portion 26. The main body portion 25 is formed in the shape of a solid or hollow shaft. The main body portion 25 is formed of an Fe-based material, such as Fe or an Fe alloy. The sliding portion 26 is formed of a sliding alloy or resin, for example, and is provided on the outer periphery of the main body portion 25. In the first embodiment, an example will be described in which the sliding portion 26 is formed of a sliding alloy. The sliding alloy used for the sliding portion 26 is any alloy, such as a Cu-based, Al-based, or Sn-based alloy. The sliding portion 26 is formed on the outer periphery of the main body portion 25 by any method, such as press-fitting, build-up welding, or plating. When a resin is used for the sliding portion 26, the resin may be, for example, a fluorine-containing resin, POM (polyacetal), PEEK (polyether ether ketone), or polyamide resin. In this case, the sliding portion 26 is formed on the outer periphery of the main body portion 25 by any method, such as spray coating, printing, welding, or impregnation. Impregnation refers to, for example, impregnating a porous sintered material with resin. The sliding portion 26 has an outer peripheral surface 27 on its outer periphery. The outer peripheral surface 27 of the sliding portion 26 is capable of sliding against the inner peripheral surface 24 of the planetary gear member 21. In other words, the outer peripheral surface 27, which is located on the outermost side of the sliding portion 26 in the shaft member 22, is capable of sliding against the inner peripheral surface 24 of the planetary gear member 21. The sliding portion 26 has annular outer walls 28 and 29 at its axial ends. The sliding portion 26 may have another layer, such as a resin overlay, provided on its surface, i.e., the outer peripheral surface 27.

[0018] In the first embodiment in which the shaft member 22 has the sliding portion 26, the overall axial length of the planetary gear member 21 is greater than the overall axial length of the sliding portion 26. Therefore, as shown in Fig. 2, the sliding portion 26 of the shaft member 22 is housed inside the planetary gear member 21 in the axial direction. As a result, the outer walls 28 and 29 of the sliding portion 26 are located inside the respective axial ends of the planetary gear member 21.

[0019] As shown in Figures 4 and 5, the outer peripheral surface 27 of the sliding portion 26 is divided into a first region 31 and a second region 32 in the circumferential direction. The first region 31 and the second region 32 are adjacent to each other within a predetermined range in the circumferential direction of the outer peripheral surface 27. When assembled to the planetary gear device 10, the planetary gear unit 16 revolves around the sun gear 13 while rotating in the direction opposite to the direction of revolution, as described above. Due to this structure unique to the planetary gear device 10, when the shaft member 22 slides against the planetary gear member 21 as the planetary gear device 10 operates, the shaft member 22 is always subjected to a large load from the planetary gear member 21 within a certain range. In other words, when the shaft member 22 slides against the planetary gear member 21, the shaft member 22 is divided into a primarily loaded portion 33 that receives a large load from the planetary gear member 21, and a secondary loaded portion 34 that receives a smaller load than the primarily loaded portion 33. Specifically, when the planetary gear device 10 is in operation, the shaft member 22 of the planetary gear unit 16 is constantly subjected to a large load in the primary load portion 33, and this range remains almost constant even when the planetary gear device 10 rotates. In the first embodiment, the first region 31 divided into sections on the outer circumferential surface 27 of the sliding portion 26 is the secondary load portion 34, and the second region 32 is the primary load portion 33.

[0020] More specifically, FIG. 5 is a developed view of the outer peripheral surface 27 in the circumferential direction. In FIG. 4, the relative rotational direction between the planetary gear member 21 and the shaft member 22 is designated as R, and as the circumferential coordinate system, the upper end side is 0° and the lower end side is 180°. That is, FIG. 5 is a developed view developed in the circumferential direction at the 90° position. When shown in this FIG. 5, the first region 31 is mainly set in the range of 180° to 360° in the coordinate system, and the second region 32 is mainly set in the range of 0° to 180° in the coordinate system. More specifically, the second region 32, which is the main load portion 33, is provided in the region of 0° to 180° in this coordinate system with a central angle D satisfying 0° < D < 150° according to the characteristics of the planetary gear device 10. In this case, it is preferable that the second region 32 serving as the main load portion 33 has a central angle D of at least 30° or more. Here, the second region 32 serving as the main load portion 33 does not necessarily become near 90° in the coordinate system as in the example shown in FIG. 4. That is, when the planetary gear member 21 and the shaft member 22 slide, the main load portion 33 where the applied load is large occurs in any range of 0° to 180° in the coordinate system according to the characteristics of the planetary gear device 10. Therefore, the second region 32 serving as the main load portion 33 is set in the region where the central angle D satisfies 0° < D < 150° within the range of 0° to 180° in the coordinate system according to the characteristics of the planetary gear device 10. And, other than the second region 32 serving as the main load portion 33 on the outer peripheral surface 27, it becomes the first region 31 serving as the sub-load portion 34.

[0021] Also, the second region 32 serving as the main load portion 33 is not limited to the example set parallel to the central axis of the shaft member 22 as shown in FIGS. 4, 5, and 6(A). That is, the second region 32 serving as the main load portion 33 may be set inclined with respect to the central axis on the outer peripheral surface 27 of the shaft member 22 as shown in FIG. 6(B) as long as it is divided in the circumferential direction of the shaft member 22. Further, the second region 32 serving as the main load portion 33 is not limited to the example set over the entire axial length of the shaft member 22, and may be set in the middle of the axial direction as shown in FIG. 6(C). Moreover, the second region 32 serving as the main load portion 33 is not limited to one as shown in FIG. 6, and may be separated into two or more in the axial direction or the circumferential direction. Thus, the second region 32 serving as the main load portion 33 is set according to the characteristics of the planetary gear device 10.

[0022] In addition to the above, the shaft member 22 has an opening 41, a connecting passage 42, and a groove 43, as shown in FIGS. 2 to 5 and 7. The opening 41 opens to the first region 31 on the outer periphery of the sliding portion 26. That is, the opening 41 opens to the first region 31 on the outer periphery 27, which is the outermost portion of the sliding portion 26. The connecting passage 42 is provided inside the shaft member 22 and connects at least one end of the shaft member 22 to the opening 41. The connecting passage 42 may connect not only one end of the shaft member 22 to the opening 41 as shown in FIG. 2, but also both ends of the shaft member 22 to the opening 41. Lubricating oil supplied from a pump (not shown) flows through the connecting passage 42. The lubricating oil is supplied to the sliding portion between the planetary gear member 21 and the shaft member 22 when the planetary gear unit 16 is configured. The lubricating oil is supplied to the opening 41 via the connecting passage 42. In the first embodiment, the connecting passage portion 42 has a passage portion 45 extending in the axial direction and a passage portion 46 extending in the radial direction, as shown in Figures 2 and 3. Note that the connecting passage portion 42 is not limited to the example shown in Figures 2 and 3, and may be inclined with respect to the axial direction or the radial direction. Furthermore, the connecting passage portion 42 is not limited to the example in which at least one end of the shaft member 22 is connected to the opening 41 by two passage portions 45 and 46. In other words, the connecting passage portion 42 may connect from the end of the shaft member 22 to the opening 41 without bending, or may have two or more bent portions.

[0023] The groove 43 is recessed radially inward from the outer peripheral surface 27 of the sliding portion 26. That is, the groove 43 is provided in a concave shape in the sliding portion 26. As shown in FIG. 7 , the groove 43 connects the opening 41 to at least one end of the sliding portion 26 in the axial direction. As such, the groove 43 has one end connected to the opening 41 and the other end, a groove end 48, located on the outer wall 29, which is an end of the sliding portion 26. As a result, the end of the groove end 48 opposite the opening 41 is open to the outer wall 29 of the sliding portion 26.

[0024] The openings 41 and grooves 43 provided in the shaft member 22 are provided in the secondary load portion 34, which is the first region 31 of the sliding portion 26, as shown in Figures 4 and 5. Specifically, in the case of the first embodiment, the openings 41 and grooves 43 are provided near 270° in the coordinate system shown in Figure 4. In other words, the openings 41 and grooves 43 are provided in the secondary load portion 34 on the substantially opposite side to the primary load portion 33 in the radial direction of the shaft member.

[0025] The connection passage 42 is connected to a discharge passage of an external pump (not shown). A pump (not shown) pressurizes the lubricating oil and supplies the lubricating oil via the connection passage 42. The lubricating oil discharged from the pump (not shown) is supplied to the connection passage 42 via a discharge passage (not shown). With this configuration, the lubricating oil supplied to the opening 41 via the connection passage 42 flows from the opening 41 along the outer circumferential surface 27 of the sliding part 26. At the same time, some of the lubricating oil that flows out from the opening 41 flows in the axial direction via the groove 43 and is discharged from the groove end 48 to the outside of the planetary gear unit 16. In other words, foreign matter that has entered the sliding portion between the inner circumferential surface 24 and the outer circumferential surface 27 is discharged from the groove end 48 through the groove 43 together with the lubricating oil flowing out from the opening 41.

[0026] The cross-sectional area of ​​the groove 43 may be approximately the same as or different from the cross-sectional area of ​​the connection passage 42. In this case, the cross-sectional area of ​​the groove 43 is preferably smaller than the cross-sectional area of ​​the connection passage 42, as shown in FIG. 8. By making the cross-sectional area of ​​the groove 43 smaller than the cross-sectional area of ​​the connection passage 42, the flow rate of lubricating oil supplied from the connection passage 42 to the groove 43 is reduced. By reducing the flow rate of lubricating oil, the capacity of a pump (not shown) can be reduced, allowing the pump to be made smaller.

[0027] Furthermore, the grooves 43 may extend in the axial direction of the shaft member 22 not only from the opening 41 to the outer wall 29 side, which is one end, but also to both the outer wall 28 side, which is the other end, as shown in FIG. 9 . By providing the grooves 43 from the opening 41 to each end side in the axial direction, the lubricating oil flowing out from the opening 41 flows in both axial directions along the outer peripheral surface 27 of the shaft member 22. Therefore, the lubricating oil can be supplied more uniformly between the inner peripheral surface 24 of the planetary gear member 21 and the outer peripheral surface 27 of the shaft member 22.

[0028] A method for manufacturing the shaft member 22 of the first embodiment having the above configuration will be described. The shaft member 22 has a main body 25 formed of, for example, an Fe-based material. Once the main body 25 is formed, a sliding portion 26 is provided on the outer periphery of the main body 25. The sliding portion 26 is provided on the main body 25 using, for example, a Cu-based, Al-based, or Sn-based alloy. The sliding portion 26 can be provided, for example, by forming it into an annular shape and press-fitting the main body 25 into its inner periphery or by shrink-fitting. Alternatively, the sliding portion 26 can be provided by overlay welding an alloy onto the outer periphery of the main body 25. By providing the sliding portion 26 by overlay welding, relative movement between the main body 25 and the sliding portion 26 is reduced compared to press-fitting or the like. Furthermore, providing the sliding portion 26 by overlay welding improves dimensional accuracy compared to press-fitting or the like. Furthermore, the sliding portion 26 may be formed of resin.

[0029] When the sliding portion 26 is provided on the main body portion 25 of the shaft member 22, a connecting passage portion 42 is formed. The connecting passage portion 42 is formed by, for example, laser processing or mechanical processing such as cutting. One end of the connecting passage portion 42 becomes an opening 41 that opens to the outer peripheral surface 27 of the sliding portion 26. In the first embodiment, the end of the connecting passage portion 42 opposite the opening 41 opens to the axial end of the main body portion 25. When the opening 41 and the connecting passage portion 42 are formed, a groove portion 43 that connects to the opening 41 is formed. The groove portion 43 is formed by laser processing or mechanical processing, similar to the connecting passage portion 42. The groove portion 43 is formed by cutting the sliding portion 26 radially from the outer peripheral surface 27. In this case, the groove portion 43 may reach the main body portion 25 in the depth direction.

[0030] Once the processing of the groove 43 is complete, the surface of the sliding portion 26 is finished. The surface is finished by, for example, polishing, cutting, or the like. The sliding portion 26 is formed slightly larger than its original outer diameter and is polished to a predetermined dimension. The groove 43 is formed taking into account the thickness of the sliding portion 26 that will be removed by this polishing. The shaft member 22 is formed by the above procedure. After polishing, the sliding portion 26 may be subjected to post-treatment such as heat treatment to stabilize its performance. Furthermore, the sliding portion 26 may have one or more optional layers, such as an overlay layer, provided on the outer peripheral surface 27 excluding the groove 43.

[0031] The operation of the planetary gear unit 16 and the planetary gear device 10 using the shaft member 22 of the first embodiment configured as described above will be described. When the planetary gear device 10 is in operation, the planetary gear member 21 rotates relative to the shaft member 22 while being supported by the shaft member 22. That is, the outer peripheral surface 27 of the shaft member 22 of the planetary gear unit 16 slides against the inner peripheral surface 24 of the planetary gear member 21. A pump (not shown) pressurizes lubricating oil and supplies it to an opening 41 via a connecting passage 42 provided inside the shaft member 22. The lubricating oil flows out of the opening 41 and is supplied to the sliding portion between the planetary gear member 21 and the shaft member 22. Some of the supplied lubricating oil flows axially from the opening 41 through the groove 43. The lubricating oil that flows axially through the groove 43 flows out of the planetary gear unit 16 from a groove end 48. At this time, any foreign matter that has entered between the planetary gear member 21 and the shaft member 22 moves to the groove 43 together with the lubricating oil due to the relative rotation between the planetary gear member 21 and the shaft member 22 and is accommodated in the groove 43. Because the lubricating oil flows in the axial direction in the groove 43, foreign matter contained in the groove 43 is discharged together with the lubricating oil from the groove end 48 to the outside of the planetary gear unit 16. As a result, foreign matter that has entered or been generated between the planetary gear member 21 and the shaft member 22 is quickly discharged from the sliding portion to the outside of the planetary gear unit 16. As a result, damage and wear caused by foreign matter can be avoided on the sliding portion 26 of the shaft member 22.

[0032] The shaft member 22 according to the first embodiment described above has the groove 43 in the sliding portion 26. Therefore, foreign matter that enters the planetary gear unit 16 from various parts of the planetary gear device 10 during operation is discharged from the groove end 48 together with the lubricating oil that flows through the groove 43. In other words, even if foreign matter enters the sliding portion between the inner circumferential surface 24 and the outer circumferential surface 27, the foreign matter is encouraged to pass through the groove 43 and be discharged from the groove end 48 together with the lubricating oil. Therefore, damage and wear to the sliding portion 26 due to foreign matter can be avoided, and a stable oil film can be formed.

[0033] In the first embodiment, the openings 41 and the grooves 43 are provided in the first region 31, which is the secondary load portion 34. The load applied to the shaft member 22 in the secondary load portion 34 during operation of the planetary gear set 10 is smaller than that in the primary load portion 33. Therefore, even if the openings 41 and the grooves 43 are formed in the secondary load portion 34, the formation of an oil film in the primary load portion 33, where a stable oil film is required, is not hindered. Therefore, when the planetary gear unit 16 is constructed, the supply of lubricating oil is ensured, and an oil film is stably formed in the portion where it is required between the inner circumferential surface 24 and the outer circumferential surface 27, i.e., in the primary load portion 33, where a large load is applied to the sliding portion 26. Therefore, a stable oil film is formed in the primary load portion 33, where a large load is applied, reducing seizure and abnormal wear, and extending the life of the planetary gear member 21 and the shaft member 22.

[0034] Furthermore, in the first embodiment, the planetary gear member 21 and the shaft member 22 are supported for relative rotation by a sliding bearing formed by a sliding portion 26 provided on the shaft member 22. This simplifies the structure and maintenance, and reduces weight, compared to, for example, rolling bearings. Therefore, when the planetary gear unit 10 is applied to, for example, a wind power generator (not shown), it is possible to achieve weight reduction and improved durability while also dealing with larger sizes and heavier loads that accompany increased output.

[0035] (Second embodiment of the shaft member) 10 to 12 show a shaft member 22 according to the second embodiment. The groove portion 43 of the shaft member 22 according to the second embodiment has a circumferential groove portion 51 and an axial groove portion 52. The circumferential groove portion 51 extends from the opening portion 41 in the circumferential direction of the sliding portion 26. The axial groove portion 52 extends in the axial direction of the sliding portion 26 from the end of the circumferential groove portion 51 opposite the opening portion 41. In this manner, the groove portion 43 may be a combination of the circumferential groove portion 51 extending in the circumferential direction and the axial groove portion 52 extending in the axial direction. The axial groove 52 has a groove end portion 48 at the end opposite the circumferential groove portion 51. The position at which the axial groove portion 52 connects to the circumferential groove portion 51 is not limited to the end of the circumferential groove portion 51. In other words, the axial groove portion 52 may connect to the circumferential groove portion 51 at any position between the opening portion 41 and the end of the circumferential groove portion 51.

[0036] 10, the axial groove 52 may have groove end portions 48 on both axial sides as shown in Figures 11 and 12. Furthermore, the groove 43 may have circumferential groove portions 51 on both sides in the circumferential direction from the opening 41 as shown in Figure 12, and the axial groove portions 52 may be connected to the ends of the circumferential groove portions 51.

[0037] In the second embodiment, the groove 43 has a circumferential groove 51 that extends circumferentially in the secondary load portion 34. This allows the lubricating oil flowing out from the opening 41 to be supplied over a wider range in the circumferential direction of the shaft member 22. At the same time, in the second embodiment, the total area of ​​the groove 43 is increased, making it possible to more reliably contain foreign matter. In the second embodiment, the groove 43 is also provided in the secondary load portion 34. Therefore, the groove 43 does not interfere with the formation of an oil film in the primary load portion 33.

[0038] (Third embodiment of shaft member) 13 to 15 show a shaft member 22 according to a third embodiment. The shaft member 22 according to the third embodiment has a throttle portion 55 between the opening 41 and the groove end 48. The throttle portion 55 has a smaller cross-sectional area than the other portions of the groove 43. Therefore, the throttle portion 55 throttles the flow of lubricating oil through the groove 43, reducing the flow rate of the lubricating oil through the groove 43. By making the cross-sectional area of ​​the throttle portion 55 smaller than the other portions of the groove 43, the flow rate of the lubricating oil through the groove 43 depends on the cross-sectional area of ​​the throttle portion 55. In other words, by providing the throttle portion 55, the flow rate of the lubricating oil is reduced regardless of the cross-sectional area of ​​the other portions of the groove 43. As a result, the capacity of the pump (not shown) that supplies the lubricating oil can be reduced. The end of the throttle portion 55 opposite the groove end 48, i.e., the end on the opening 41 side, is a start portion 56 where the cross-sectional area of ​​the groove 43 begins to decrease, as shown in FIG. 13 .

[0039] The throttle portion 55 is provided beyond a range G that is 3% of the outer diameter of the sliding portion 26 from the groove end 48 toward the opening 41. That is, the range G is a position that is 3% of the outer diameter of the sliding portion 26 from the groove end 48 toward the opening 41. The start portion 56 of the throttle portion 55 is set beyond this range G toward the opening 41. By setting the throttle portion 55 under these conditions, even if the flow rate of the lubricating oil is restricted by the throttle portion 55, the lubricating oil is sufficiently supplied between the inner circumferential surface 24 and the outer circumferential surface 27. At the same time, by setting the range G of the throttle portion 55 as described above, the discharge of foreign matter by the lubricating oil flowing through the groove portion 43 is also sufficiently ensured.

[0040] The narrowed portion 55 may have a minimum cross-sectional area at any position as long as the start portion 56 is closer to the opening 41 than the range G. Specifically, the narrowed portion 55 is configured as a portion where the cross-sectional area decreases at the tip of the groove 43, as shown in FIG. 16(A). The narrowed portion 55 may also be a tapered portion where the cross-sectional area gradually decreases, as shown in FIGS. 16(B) and 16(C). The narrowed portion 55 may be partially tapered, as shown in FIG. 16(B), or entirely tapered, as shown in FIG. 16(C). Furthermore, the narrowed portion 55 may only have a partially reduced cross-sectional area. Therefore, the cross-sectional area of ​​the narrowed portion 55 may be larger on the groove end 48 side than the minimum cross-sectional area, as shown in FIG. 16(D). Additionally, even if the groove 43 is inclined with respect to the axis of the shaft member 22, as shown in FIG. 16(E), the start portion 56 of the narrowed portion 55 may be closer to the opening 41 than the range G.

[0041] As described above, the throttle portion 55 only needs to include a portion having a smaller cross-sectional area than the other portions of the groove portion 43. Therefore, there is no restriction on the depth of the throttle portion 55, i.e., the total length in the radial direction of the shaft member 22. In other words, as long as the throttle portion 55 has a configuration in which the cross-sectional area is smaller than the other portions of the groove portion 43, the depth and cross-sectional shape can be set as desired, as shown in Figures 17(A) to 17(F).

[0042] In the third embodiment, the groove 43 has a throttle portion 55. This reduces the amount of lubricating oil consumed. This reduces the performance required of a pump (not shown) that supplies the lubricating oil while maintaining the ability to discharge foreign matter. In addition, in the third embodiment, by setting the position of the throttle portion 55, the flow rate of the lubricating oil is limited, thereby ensuring sufficient lubrication of the sliding parts with the lubricating oil and achieving the discharge of foreign matter by the lubricating oil flowing through the groove 43.

[0043] (Fourth embodiment of shaft member) 18 to 24 show a shaft member according to the fourth embodiment. Figures 18 to 24 correspond to developments of the outer peripheral surface 27 shown in Figure 5. At least a portion of the groove 43 of the shaft member 22 according to the fourth embodiment is inclined with respect to the axis of the shaft member 22. In the example shown in FIG. 18, the two axial grooves 52 are inclined with respect to the axis of the shaft member 22. The two axial grooves 52 are generally parallel. The inclination angles H1, H2 of the axial grooves 52 are preferably approximately 0° to 55°. Furthermore, in the example shown in FIG. 18, the sum of the circumferential angle region a and the angle region b is 300° or less, which falls within the first region 31 that becomes the secondary load portion 34, that is, a + b ≦ 300°.

[0044] In the example shown in FIG. 19, the two axial grooves 52 are inclined at different angles relative to the axis. In the example shown in FIG. 19, the two axial grooves 52 are inclined approximately symmetrically with respect to an axis passing through the openings 41 in the developed view. In the example shown in FIG. 20, two openings 41 are provided. In the example shown in FIG. 20, the circumferential groove 51 is connected to each of the two openings 41, and its ends are connected to each of the two axial grooves 52. In the examples shown in FIGS. 21 and 22, the axial grooves 52 are inclined while bending in the axial direction. As shown in FIG. 21, the groove 43 can be configured to be connected to the opening 41 via one circumferential groove 51. Alternatively, the groove 43 can be configured to extend to both ends in the axial direction as an inclined groove 43 without providing a circumferential groove 51, as shown in FIG. 22.

[0045] Furthermore, the groove portions 43 may have shapes as shown in Figures 23 and 24. In this case, the shaft member 22 has four groove portions 43 that are inclined in the axial direction. All four groove portions 43 may be configured to connect to openings 41 as shown in Figure 23. Alternatively, the four groove portions 43 may be configured to connect to two or more openings 41 as shown in Figure 24.

[0046] In the fourth embodiment, at least a portion of the groove 43 is inclined with respect to the axis of the shaft member 22. Specifically, at least one of the circumferential groove 51 and the axial groove 52 of the groove 43 is inclined with respect to the axis of the shaft member 22. Both the circumferential groove 51 and the axial groove 52 may be inclined with respect to the axis of the shaft member 22. As a result, the groove 43 is provided over a wide area in the portion where the inner circumferential surface 24 and the outer circumferential surface 27 slide. This allows the sliding portions to be more sufficiently lubricated by the lubricating oil. This allows for the formation of a more stable oil film and the discharge of foreign matter.

[0047] (Other embodiments) The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist of the invention. In the above-described embodiments, an example has been described in which the end of the connecting passage portion 42 opposite the opening 41 is connected to the axial end of the shaft member 22. However, the end of the connecting passage portion 42 opposite the opening 41 is not limited to the axial end of the shaft member 22, and may be configured to be connected to an outer wall midway in the axial direction of the shaft member 22, as shown in Fig. 25 , for example. [Explanation of symbols]

[0048] In the drawings, reference numeral 10 denotes a planetary gear device, 11 denotes a first shaft member, 12 denotes a second shaft member, 13 denotes a sun gear, 14 denotes an internal gear, 15 denotes a carrier, 16 denotes a planetary gear unit, 21 denotes a planetary gear member, 22 denotes a shaft member, 24 denotes an inner circumferential surface, 25 denotes a main body portion, 26 denotes a sliding portion, 27 denotes an outer circumferential surface, 28 and 29 denote an outer wall, 31 denotes a first region, 32 denotes a second region, 33 denotes a main load portion, 34 denotes a secondary load portion, 41 denotes an opening, 42 denotes a connecting passage portion, 43 denotes a groove portion, 48 denotes a groove end portion, 51 denotes a circumferential groove portion, 52 denotes an axial groove portion, and 55 denotes a throttle portion.

Claims

1. A shaft member that slides against the inner peripheral surface of the planetary gear member, a main body; a sliding portion provided on an outer peripheral side of the main body portion, having an outer peripheral surface that slides against the inner peripheral surface, the outer peripheral surface being divided in a circumferential direction into a first region and a second region other than the first region; an opening portion that is open to the first region on the outer circumferential side of the sliding portion; a connecting passage portion provided inside the shaft member, one end of the connecting passage portion being connected to the opening portion; a groove portion recessed radially inward from the outer peripheral surface, connecting the opening and at least one end of the sliding portion in the axial direction, and having a groove end portion opposite the opening portion that opens to an outer wall at the end of the sliding portion in the axial direction; A shaft member comprising:

2. The groove portion connects the opening portion to both axial ends of the sliding portion. The shaft member according to claim 1 .

3. The groove portion is provided in the first region. The shaft member according to claim 1 .

4. the sliding portion is divided into a main load portion that receives a larger load from the planetary gear member when sliding on the planetary gear member, and a secondary load portion that receives a smaller load than the main load portion, The first region is the secondary load portion. The shaft member according to claim 1 .

5. The groove portion and the connecting passage portion have different cross-sectional areas. The shaft member according to claim 1 .

6. The groove portion has a circumferential groove portion extending from the opening portion in the circumferential direction of the sliding portion, and an axial groove portion extending from an end side of the circumferential groove portion opposite the opening portion in the axial direction of the sliding portion. The shaft member according to claim 1 .

7. At least one of the circumferential groove portion and the axial groove portion is inclined with respect to the axial direction of the sliding portion. The shaft member according to claim 6.

8. The groove portion has a narrowed portion between the opening and the groove end portion, the narrowed portion having a smaller cross-sectional area than other portions. The shaft member according to any one of claims 1 to 7.

9. The throttle portion is provided starting from the groove end portion and extending from the groove end portion toward the opening portion beyond a range G that is 3% of the outer diameter of the sliding portion. The shaft member according to claim 8.

10. The throttle portion has a cross-sectional area that changes in the axial direction of the sliding portion. The shaft member according to claim 8.

11. The shaft member according to claim 1; the planetary gear member provided on the outer circumferential side of the shaft member; A planetary gear unit comprising:

12. A first shaft member; a sun gear provided on the first shaft member; one or more planetary gear units according to claim 11 , which mesh with the sun gear on an inner peripheral side and mesh with the internal gear on an outer peripheral side; a carrier to which the shaft member of the planetary gear unit is fixed and which is connected to a second shaft member; A planetary gear device comprising:

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