Planetary gear mechanism

Abstract

To provide a planetary gear mechanism that can reduce stirring losses. [Solution] The planetary gear mechanism 11 comprises a planetary gear 22, a planetary carrier pin 23, a needle bearing 24, and a planetary carrier 25. The planetary carrier pin 23 rotatably supports the planetary gear 22. The planetary carrier 25 supports both ends of the planetary carrier pin 23. The planetary gear 22 has discharge passages 35, 36 for discharging lubricating oil from the space S where the needle bearing 24 is located.

Description

Technical Field

[0001] The present invention relates to a planetary gear mechanism.

Background Art

[0002] A planetary gear mechanism is used in a transmission or the like. The planetary gear mechanism includes a sun gear, a plurality of planetary gears arranged around the sun gear, and a ring gear arranged around the plurality of planetary gears. The plurality of planetary gears are supported by a planetary carrier (see Patent Document 1). The planetary gear is arranged on a pin supported by the planetary carrier via a bearing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, with the need for electrification, high-speed rotation has been required for transmissions and the like. However, the influence of the stirring loss of lubricating oil has increased due to high-speed rotation, and reduction of the stirring loss has been demanded.

[0005] An object of the present disclosure is to provide a planetary gear mechanism capable of reducing the stirring loss.

Means for Solving the Problems

[0006] The planetary gear mechanism according to the first aspect of the present disclosure includes a planetary gear, a shaft member, a bearing, and a planetary carrier. The shaft member rotatably supports the planetary gear. The planetary carrier supports the shaft member. The planetary gear has a discharge flow path for discharging lubricating oil from a space where the bearing is arranged.

[0007] A planetary gear mechanism according to a second aspect of the present disclosure comprises a planetary gear, a shaft member, a bearing, and a planetary carrier. The shaft member rotatably supports the planetary gear. The planetary carrier supports the shaft member. The shaft member has a discharge channel for discharging lubricating oil from the space in which the bearing is located. [Effects of the Invention]

[0008] According to this disclosure, a planetary gear mechanism capable of reducing stirring losses can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing the drive system of a work machine in Embodiment 1 according to this disclosure. [Figure 2] A cross-sectional view showing the planetary gear mechanism in Embodiment 1 according to this disclosure. [Figure 3A] This is a perspective view showing the appearance of the planetary gear and planetary carrier in Embodiment 1 of the present disclosure. [Figure 3B] This is a partial cross-sectional view of Figure 3A. [Figure 4] (a) is a perspective view of the planetary gear 22. (b) is a partial cross-sectional view of Figure 4(a). [Figure 5] This is a front view of the sun gear, planetary gear, and planetary carrier in Embodiment 1 of the present disclosure. [Figure 6] This is a side view of the sun gear, planetary gear, and planetary carrier in Embodiment 1 of the present disclosure. [Figure 7] Figure 5 is a cross-sectional view between BB. [Figure 8] (a) is a cross-sectional view between CC in Figure 6. (b) is a cross-sectional view between D and C in Figure 6. [Figure 9] This is an enlarged view of section E in Figure 7. [Figure 10]This is a diagram for explaining the range where lubricating oil accumulates as the planetary gear and the planetary carrier without a discharge passage rotate. [Figure 11] This is a partially enlarged view of the planetary gear mechanism according to Embodiment 2 of the present disclosure. [Figure 12] This is a perspective view of the planetary carrier pin according to Embodiment 2 of the present disclosure. [Figure 13] This is a partially enlarged view of the planetary gear mechanism according to Embodiment 3 of the present disclosure. [Figure 14] This is a perspective view of the planetary carrier pin according to Embodiment 3 of the present disclosure. [Figure 15] This is a partially sectional perspective view of the planetary gear mechanism according to Embodiment 3 of the present disclosure. [Figure 16] This is a schematic diagram showing the drive system of a working machine in a modified example of the embodiment of the present disclosure.

Mode for Carrying Out the Invention

[0010] The planetary gear mechanism of the embodiment will be described with reference to the drawings. The inventors have found that a large proportion of the stirring loss generated in the planetary gear mechanism occurs in the needle bearing disposed between the planetary carrier pin and the planetary gear. In the embodiment of the present application, a planetary gear mechanism capable of reducing the stirring loss generated in the needle bearing is disclosed.

[0011] (Embodiment 1) (Configuration) (Overview of the drive system 2 of the working machine 1) FIG. 1 is a schematic diagram showing the drive system 2 of the working machine 1. The drive system 2 of the working machine 1 is an electric drive type. The drive system 2 includes a battery 3, an inverter 4, an electric motor 5, a speed reducer 6, a transfer 7, axles 8a and 8b, a pair of rear tires 9, and a pair of front tires 10. The battery 3 stores electricity. The inverter 4 converts the DC supplied from the battery 3 into AC. The electric motor 5 is rotationally driven by the AC supplied from the inverter 4.

[0012] The speed reducer 6 reduces the rotation of the electric motor 5 and transmits it to the transfer 7. The planetary gear mechanism 11 (described later) of the present embodiment is used for, for example, the speed reducer 6.

[0013] The transfer 7 distributes the driving force transmitted from the speed reducer 6 to the front and rear axles 8a, 8b. A pair of rear tires 9 are connected to the rear axle 8a. The pair of rear tires 9 rotate by the power from the electric motor 5 distributed to the rear axle 8a. A pair of front tires 10 are connected to the front axle 8b. The pair of front tires 10 rotate by the power from the electric motor 5 distributed to the front axle 8b.

[0014] (Planetary gear mechanism 11) FIG. 2 is a cross-sectional view showing the planetary gear mechanism 11 of the present embodiment.

[0015] The planetary gear mechanism 11 includes an input shaft 20, a sun gear 21, a plurality of planetary gears 22, a planetary carrier pin 23 (shaft member), a needle bearing 24 (bearing), a planetary carrier 25, a ring gear 26, a fixing member 27, an output shaft 28, and a housing 29.

[0016] (Input shaft 20) Power is input to the input shaft 20. In FIG. 1, the power of the electric motor 5 is input to the input shaft 20. The input shaft 20 is a cylindrical member. The input shaft 20 is inserted into the housing 29. The input shaft 20 is rotatably supported with respect to the housing 29 by a bearing 65 disposed in the housing 29. In FIG. 2, the central axis of the input shaft 20 is shown as O. The input shaft 20 is disposed coaxially with the output shaft 28 described later. Among the directions parallel to the central axis O, the direction from the input shaft 20 toward the output shaft 28 is defined as the first direction A1, and the direction opposite to the first direction A1 and from the output shaft 28 toward the input shaft 20 is defined as the second direction A2.

[0017] (Sangiya 21) The sun gear 21 is fixed to the input shaft 20. The sun gear 21 is positioned coaxially with the input shaft 20. The sun gear 21 is positioned around the end of the input shaft 20 located within the housing 29. The sun gear 21 rotates together with the input shaft 20 about axis O.

[0018] (Planetary Gear 22) Multiple planetary gears 22 are arranged around the sun gear 21 and mesh with the sun gear 21. Figure 3A is a perspective view showing the external appearance of the planetary gears 22 and planetary carrier 25. Figure 3B is a cross-sectional perspective view of Figure 3A. Figure 4(a) is a perspective view of the planetary gear 22. Figure 4(b) is a cross-sectional perspective view of Figure 4(a). Figure 5 is a front view of the sun gear 21, planetary gears 22 and planetary carrier 25 viewed from a first direction A1 along axis O. Figure 6 is a side view of the sun gear 21, planetary gears 22 and planetary carrier 25. Figure 7 is a cross-sectional view between B and C in Figure 5. Figure 8(a) is a cross-sectional view between C and C in Figure 6, and Figure 8(b) is a cross-sectional view between D and D in Figure 6. Figure 9 is an enlarged view of section E in Figure 7.

[0019] Multiple planetary gears 22 are arranged on the outer circumference of the sun gear 21 shown in Figure 2 and mesh with the sun gear 21. In the planetary gear mechanism 11 of this embodiment, three planetary gears 22 are provided, as shown in Figures 3A, 3B, and 5. The planetary gears 22 are rotatably supported by planetary carrier pins 23. The planetary gears 22 rotate around an axis 23c parallel to axis O.

[0020] Each planetary gear 22 includes an inner circumferential surface 31, an outer circumferential surface 32, a first side surface 33, a second side surface 34, and a plurality of discharge passages 35, 36, as shown in Figures 4(a), 4(b), and 7. The inner circumferential surface 31 is a surface facing radially inward. The inner circumferential surface 31 is a surface facing the axis 23c. The inner circumferential surface 31 is the surface facing the planetary carrier pin 23. The inner circumferential surface 31 is in contact with the needle bearing 24. The outer circumferential surface 32 has a toothed shape and meshes with the sun gear 21. The outer circumferential surface 32 is a surface facing radially outward. The first side surface 33 is a surface perpendicular to the axis 23c. The first side surface 33 is located between the end of the inner circumferential surface 31 on the first direction A1 side and the end of the outer circumferential surface 32 on the first direction A1 side. The first side surface 33 has an annular recess 33a centered on the axis 23c. The second side surface 34 is a surface perpendicular to the axis 23c. The second side surface 34 is located between the end of the inner circumferential surface 31 on the second direction A2 side and the end of the outer circumferential surface 32 on the second direction A2 side. The second side surface 34 has an annular recess 34a centered on the axis 23c.

[0021] Multiple discharge passages 35 and 36 are provided to discharge lubricating oil from the planetary gear 22 from the space S in which the needle bearing 24 is located, as shown in Figures 3B and 9. The multiple discharge passages 35 are formed as through holes from the inner circumferential surface 31 to the recess 33a of the first side surface 33. In this embodiment, four discharge passages 35 are provided. The four discharge passages 35 are arranged at equal intervals in the circumferential direction. Each discharge passage 35 has an inlet 35a into which lubricating oil flows and an outlet 35b into which lubricating oil is discharged. The inlet 35a is located at the end of the inner circumferential surface 31 in the direction along the axis 23c. The outlet 35b is located in the recess 33a of the first side surface 33. As shown in Figure 9, each discharge passage 35 is formed inclined with respect to the axis 23c so as it moves radially outward toward the first direction A1.

[0022] As shown in Figures 3B and 9, the multiple discharge channels 36 are formed as through holes extending from the inner circumferential surface 31 to the recess 34a of the second side surface 34. In this embodiment, as shown in Figures 4(a) and 4(b), four discharge channels 36 are provided. The four discharge channels 36 are arranged at equal intervals in the circumferential direction. Each discharge channel 36 has an inlet 36a into which lubricating oil flows and an outlet 36b into which lubricating oil is discharged, as shown in Figures 4(b) and 9. The inlet 36a is located at the end of the inner circumferential surface 31 opposite to the inlet 36c in the direction along the axis 23c. The outlet 36b is located in the recess 34a of the second side surface 34. Each discharge channel 36 is formed inclined with respect to the axis 23c so as it moves radially outward toward the second direction A2.

[0023] The planetary gear 22 in this embodiment is provided with four discharge channels 35 and four discharge channels 36, for a total of eight discharge channels. The discharge channels 35 and 36 are arranged opposite each other in the direction of the central axis O. As shown in Figure 9, the discharge channels 35 and 36 are formed symmetrically in a side cross-sectional view.

[0024] (Planetary carrier pin 23) Multiple planetary carrier pins 23 rotatably support multiple planetary gears 22. As shown in Figure 2, the planetary carrier pins 23 are inserted into the center of the planetary gears 22. As shown in Figure 8(a), a planetary carrier pin 23 is provided for each planetary gear 22. In this embodiment, three planetary carrier pins 23 are provided corresponding to three planetary gears 22. The central axis of the planetary carrier pin 23 is shown as axis 23c. As mentioned above, axis 23c is the rotation center of the planetary gear 22.

[0025] As shown in Figures 3B and 9, the planetary carrier pin 23 has a first end 41, a second end 42, and a pin supply channel 43. The planetary carrier pin 23 is supported by the planetary carrier 25 by the first end 41 and the second end 42. The first end 41 is the end of the planetary carrier pin 23 on the first direction A1 side. The end face of the planetary carrier pin 23 on the first direction A1 side (the end face of the first end 41) is shown as 41e. The second end 42 is the end of the planetary carrier pin 23 on the second direction A2 side. The end face of the planetary carrier pin 23 on the second direction A2 side (the end face of the second end) is shown as 42e.

[0026] The first end 41 is inserted into the planetary carrier 25, and the outer peripheral surface 41a of the outer peripheral surface 23a of the planetary carrier pin 23 is in contact with the planetary carrier 25. The second end 42 is inserted into the planetary carrier 25, and the outer peripheral surface 42a of the outer peripheral surface 23a is in contact with the planetary carrier 25.

[0027] The pin supply channel 43 is a channel that supplies lubricating oil to the space S (described later) where the needle bearing 24 is located. As shown in Figures 3B and 9, the pin supply channel 43 is formed as a hole passing through the inside of the planetary carrier pin 23. As shown in Figure 9, the pin supply channel 43 has a first portion 431, a second portion 432, and a third portion 433. The first portion 431 is positioned perpendicular to the axis 23c. The first portion 431 is formed from a supply port 43a formed on the central axis O side of the outer circumferential surface 41a to the central axis 23c. The supply port 43a is positioned closest to the central axis O in the circumferential direction of the outer circumferential surface 23a. As shown in Figures 8(a), 8(b), and 9, the second portion 432 is formed along the central axis 23c from the end of the first portion 431 on the central axis 23c side toward the second direction A2. As shown in Figures 8(a) and 9, the third portion 433 is formed from the end of the second portion 432 on the second direction A2 side to the outlet 43b formed on the outer circumferential surface 23a on the side of the central axis O. The third portion 433 is formed perpendicular to the central axis O. The outlet 43b opens into the space S (described later) where the needle bearing 24 is located. The outlet 43b opens toward the central axis O. The outlet 43b is located in the part of the outer circumferential surface 23a of the planetary carrier pin 23 that is closest to the central axis O in the circumferential direction. Note that the number of outlets 43b is not limited to one, but may be two or more.

[0028] (Needle bearing 24) As shown in Figures 3B, 8, and 9, the needle bearing 24 is positioned between the planetary gear 22 and the planetary carrier pin 23. The needle bearing 24 is positioned around the planetary carrier pin 23. The planetary gear 22 is positioned around the needle bearing 24. The space S in which the needle bearing 24 is positioned is a cylindrical space enclosed by the planetary gear 22, the planetary carrier pin 23, and a pair of washers 30 (described later). As shown in Figure 9, the needle bearing 24 has needle bearing rollers 45 and a needle bearing cage 46. The needle bearing rollers 45 are rotatably held by the needle bearing cage 46. The rotation of the needle bearing rollers 45 causes the planetary gear 22 to rotate around the planetary carrier pin 23, which is fixed to the planetary carrier 25.

[0029] (Planetary Career 25) The planetary carrier 25 supports a plurality of planetary carrier pins 23. The plurality of planetary carrier pins 23 are fixed to the planetary carrier 25 as shown in Figure 3B. The planetary carrier 25 has a first carrier disk 51, a second carrier disk 52, a plurality of carrier columns 53 (see Figure 8(a)), a first carrier boss 54, a second carrier boss 55, and a carrier supply channel 56, as shown in Figure 2.

[0030] The first carrier disk 51 is disc-shaped. As shown in Figures 2 and 3B, the first ends 41 (ends on the first direction A1 side) of multiple planetary carrier pins 23 are fixed to the first carrier disk 51. Multiple through holes parallel to the central axis O are arranged circumferentially in the first carrier disk 51. The first ends 41 of the planetary carrier pins 23 are inserted into these through holes and fixed to the first carrier disk 51. The inner circumferential surface of the through hole into which the first end 41 is inserted is shown as 51a in Figures 2 and 9. The first carrier disk 51 is positioned on the first direction A1 side of multiple planetary gears 22. Through holes are formed in the first carrier disk 51 along the central axis O, and output shafts 28 are inserted into these through holes. The inner circumferential surface of the through hole in the first carrier disk 51 into which the output shafts 28 are inserted is shown as 51b in Figures 2 and 9.

[0031] The first carrier disk 51 has a plurality of carrier supply channels 56, as shown in Figures 3B and 9. Each carrier supply channel 56 is a channel that supplies lubricating oil to each pin supply channel 43 of the plurality of planetary carrier pins 23. The carrier supply channels 56 are formed from the inner circumferential surface 51b to the inner circumferential surface 51a, as shown in Figure 9. The carrier supply channels 56 are arranged perpendicular to the central axis O. The carrier supply channels 56 are connected to the pin supply channels 43, as shown in Figure 9.

[0032] The second carrier disk 52 is disc-shaped. Multiple through holes are arranged circumferentially in the second carrier disk 52, parallel to the central axis O. The second ends 42 (ends on the second direction A2 side) of multiple planetary carrier pins 23 are inserted into these through holes, and the second ends 42 are fixed to the second carrier disk 52. The second carrier disk 52 is positioned on the second direction A2 side of multiple planetary gears 22. As shown in Figure 2, through holes are formed in the second carrier disk 52 along the central axis O, and the input shaft 20 is inserted into these through holes.

[0033] A planetary gear 22 is positioned between the first carrier disk 51 and the second carrier disk 52. A washer 30 is positioned between the first carrier disk 51 and the first side surface 33 of the planetary gear 22, and another washer 30 is positioned between the second carrier disk 52 and the second side surface 34 of the planetary gear 22.

[0034] As shown in Figures 7, 8(a), and 8(b), the multiple carrier pillars 53 are arranged between the first carrier disk 51 and the second carrier disk 52. The multiple carrier pillars 53 connect the first carrier disk 51 and the second carrier disk 52. As shown in Figure 8(a), the carrier pillars 53 are arranged between adjacent planetary gears 22 in the circumferential direction.

[0035] As shown in Figure 6, the first carrier boss 54 protrudes from the first carrier disk 51 toward the first direction A1. As shown in Figure 2, the output shaft 28 is inserted inside the first carrier boss 54.

[0036] As shown in Figure 6, the second carrier boss 55 protrudes from the second carrier disk 52 toward the second direction A2. An input shaft 20 is inserted inside the second carrier boss 55, as shown in Figure 2A.

[0037] As shown in Figure 2, the first carrier boss 54 is rotatably supported in the housing 29 via a bearing 57. The second carrier boss 55 is rotatably supported in the housing 29 via a bearing 58.

[0038] (Ring gear 26) As shown in Figure 2, the ring gear 26 is arranged around a plurality of planetary gears 22. The ring gear 26 is annular in shape. The inner circumferential surface of the ring gear 26 has tooth surfaces that mesh with the tooth surfaces of the planetary gears 22. The ring gear 26 is fixed to the housing 29 via a fixing member 27.

[0039] (Fixing member 27) The fixing member 27 secures the ring gear 26 to the housing 29. The fixing member 27 is annular in shape. The fixing member 27 is positioned on the outer circumference of the ring gear 26. The fixing member 27 is fixed to the housing 29, which will be described later. The fixing member 27 meshes with the teeth positioned on the outer circumference of the ring gear 26. As a result, the ring gear 26 is coupled to the housing 29 in a way that prevents relative rotation.

[0040] (Output shaft 28) The output shaft 28 outputs power reduced by a sun gear 21, multiple planetary gears 22, a planetary carrier 25, and a ring gear 26. The output shaft 28 is located coaxially (on the central axis O) with the input shaft 20, as shown in Figure 2. The output shaft 28 meshes with the planetary carrier 25 by spline teeth. The output shaft 28 is rotatably supported relative to the housing 29 by multiple bearings 59 located in the housing 29. Through holes are formed in the first carrier disc 51 and the first carrier boss 54 of the planetary carrier 25 along the axis O. The output shaft 28 is inserted into these through holes and fixed to the second carrier disc 52 and the second carrier boss 55.

[0041] The output shaft 28 has a shaft supply channel 60. The shaft supply channel 60 is a channel that supplies lubricating oil to the carrier supply channel 56. The shaft supply channel 60 has a first section 601, a second section 602, a third section 603, and a fourth section 604. The first section 601 is a groove formed along the circumferential direction on the outer surface of the output shaft 28. The second section 602 is formed from the first section 601 toward the central axis O of the output shaft 28. The third section 603 is formed from the central end of the second section 602 toward the vicinity of the end of the output shaft 28 toward the second direction A2, as shown in Figure 2. The fourth section 604 is formed radially outward from the end of the third section 603 toward the second direction A2 and is connected to the carrier supply channel 56 of the planetary carrier 25.

[0042] (Housing 29) The housing 29 accommodates the sun gear 21, the planetary gear 22, the planetary carrier pin 23, the needle bearing 24, the planetary carrier 25, the ring gear 26, and the fixing member 27. The input shaft 20 and the output shaft 28 are inserted into the housing 29.

[0043] As shown in Figure 2, the housing 29 has a first support portion 61, a second support portion 62, a third support portion 63, and a fourth support portion 64.

[0044] The first support portion 61 is positioned on the second direction A2 side of the second carrier disk 52 of the planetary carrier 25. The first support portion 61 has a wall portion 611 and a projection portion 612. The wall portion 611 is positioned parallel to the second carrier disk 52. The wall portion 611 is positioned around the second carrier boss 55 of the planetary carrier 25. The projection portion 612 protrudes from the wall portion 611 toward the second direction A2. The projection portion 612 has a through hole into which the input shaft 20 is inserted. A bearing 65 is positioned between the inner wall of the through hole in the projection portion 612 and the input shaft 20. This allows the housing 29 to rotatably support the input shaft 20. The wall portion 611 has a through hole along axis O. The second carrier boss 55 is inserted into this through hole. A bearing 58 is positioned between the inner wall of the through hole in the wall portion 611 and the second carrier boss 55 of the planetary carrier 25. As a result, the first support portion 61 rotatably supports the second carrier boss 55.

[0045] The second support portion 62 is positioned to cover the first direction A1 side of the first carrier disk 51 and the radially outer side of the ring gear 26. The second support portion 62 has a wall portion 621 and an outer edge portion 622. The wall portion 621 is positioned on the first direction A1 side of the first carrier disk 51. The wall portion 621 has a through hole along the axis O. The first carrier boss 54 is inserted into this through hole. The second support portion 62 rotatably supports the first carrier boss 54. A bearing 57 is positioned between the inner wall of the through hole in the wall portion 621 and the first carrier boss 54.

[0046] The outer edge portion 622 extends from the outer peripheral end of the wall portion 621 toward the second direction A2. The end of the outer edge portion 622 toward the second direction A2 is connected to the outer peripheral portion of the wall portion 611.

[0047] The planetary carrier 25 is rotatably supported by the housing 29 by the first support portion 61 rotatably supporting the second carrier boss 55 and the second support portion 62 rotatably supporting the first carrier boss 54.

[0048] The third support portion 63 is positioned on the first direction A1 side of the second support portion 62. The third support portion 63 is fixed to the second support portion 62. The third support portion 63 has a through hole along the axis O. The output shaft 28 is inserted into the through hole. Multiple bearings 59 are positioned between the inner wall of the through hole and the output shaft 28. As a result, the third support portion 63 rotatably supports the output shaft 28.

[0049] The fourth support portion 64 is positioned on the first direction A1 side of the third support portion 63. The fourth support portion 64 is fixed to the third support portion 63. The fourth support portion 64 has a through hole along axis O. The output shaft 28 is inserted into the through hole. The fourth support portion 64 has a housing supply passage 68. The housing supply passage 68 supplies lubricating oil to the shaft supply passage 60. The housing supply passage 68 is formed from the outer surface of the fourth support portion 64 to the output shaft 28. The housing supply passage 68 is connected to the first portion 601 of the shaft supply passage 60. Lubricating oil is supplied to the housing supply passage 68 from the tank 12 via a passage 69 (indicated by an arrow in Figure 2) by the drive of a pump (not shown).

[0050] (Lubricant flow) As the input shaft 20 rotates, lubricating oil is supplied from the tank 12 to the passage 69 by the pump. The lubricating oil supplied to the passage 69 flows into the housing supply passage 68, which is connected to the passage 69. The lubricating oil that flows into the housing supply passage 68 is supplied to the space S where the needle bearing 24 is located, via the shaft supply passage 60, the carrier supply passage 56, and the pin supply passage 43.

[0051] Meanwhile, the lubricating oil supplied to the space S is discharged from the space S to the outside of the planetary gear 22 through the discharge passage 35 and the discharge passage 36 by the rotation of the planetary gear 22 and the planetary carrier 25 (see solid arrows in Figure 9). The lubricating oil discharged to the outside of the planetary gear 22 is returned to the tank 12 through the discharge passage 75 that connects the housing 29 and the tank 12. As shown by the dotted arrows in Figure 9, the lubricating oil in the space S is also discharged from the gap necessary for assembling the planetary gear 22 and the washer 30, as in the conventional design. However, in the planetary gear mechanism 11 of this embodiment, the lubricating oil can be efficiently discharged from the space S by providing the discharge passage 35 and the discharge passage 36.

[0052] (Features) In the planetary gear mechanism 11 of this embodiment, the planetary gear 22 has discharge passages 35 and 36 that discharge lubricating oil from the space S in which the needle bearing 24 is located. As a result, the lubricating oil supplied to space S is discharged through the discharge passages 35 and 36 by the rotation of the planetary gear 22 and the planetary carrier 25, thereby suppressing the accumulation of excess lubricating oil in space S and reducing agitation loss. In addition, it is possible to suppress the accumulation of oil that has become hot (oil that does not function as a cooling oil) by absorbing heat from the needle bearing 24, thereby reducing agitation loss.

[0053] Figure 10 is a diagram illustrating the location where lubricating oil accumulates as the planetary gear 1022 and planetary carrier 25 rotate, in which there are no discharge channels 35 and 36. Fluid analysis of the movement of the lubricating oil confirmed that it accumulates in ranges R1 and R2. Range R1 is the area of ​​the inner circumferential surface 31 of the planetary gear 22 that is opposite to the central axis O of the planetary carrier 25. In Figure 10, which is a front view along axis O, if we define L2 as a line perpendicular to the line L1 that passes through the center of the planetary gear 1022 and the center of the planetary carrier 25, then range R1 is the area of ​​the inner circumferential surface 31 that is radially outside the line L2 of the planetary carrier 25. Due to centrifugal force, an outward force acts on the lubricating oil of the planetary carrier 25, causing the lubricating oil to adhere to range R1 and accumulate there. Furthermore, range R2 is the area on the inner circumference side (towards the central axis O) of the planetary carrier 25 within the outer circumferential surface 23a of the planetary carrier pin 23. Range R2 is the area radially inward of the planetary carrier 25 from the straight line L2 within the outer circumferential surface 23a. Due to centrifugal force, an outward force acts on the lubricating oil of the planetary carrier 25, causing the lubricating oil to adhere to and accumulate in range R2.

[0054] In this embodiment 1, lubricating oil can be discharged from the inner circumferential surface 31 of the planetary gear 22 through the discharge passages 35 and 36 within the planetary gear 22. In this way, the planetary gear mechanism 11 of this embodiment 1 discharges the lubricating oil from a position where it tends to accumulate, thus enabling efficient discharge of the lubricating oil and reducing agitation loss.

[0055] (Embodiment 2) Next, the planetary gear mechanism 111 of Embodiment 2 will be described. Compared to the planetary gear mechanism 11 of Embodiment 1, the planetary gear mechanism 111 of Embodiment 2 does not have discharge passages 35 and 36 in the planetary gear 22, and discharge passages 71 and 72 are provided in the planetary carrier pin 23. In Embodiment 2, the differences from Embodiment 1 will be described, and similar configurations will not be described.

[0056] (composition) Figure 11 is a partially enlarged view of the planetary gear mechanism 111 of this second embodiment. Figure 11 shows portion E of Figure 7, similar to Figure 9. The planetary gear mechanism 111 of this second embodiment has a planetary gear 122 in which discharge passages 35 and 36 are not formed. The planetary gear 122 has the same configuration as the planetary gear 22 of the first embodiment, except that the discharge passages 35 and 36 are not formed.

[0057] The planetary gear mechanism 111 of this second embodiment has a planetary carrier pin 123. The planetary carrier pin 123 has discharge passages 71 and 72. The planetary carrier pin 123 has the same configuration as the planetary carrier pin 23 of embodiment 1, except that it has discharge passages 71 and 72. Figure 12 is a perspective view of the planetary carrier pin 123.

[0058] The discharge passages 71 and 72 discharge lubricating oil from the space S to the outside of the planetary carrier pin 123. The discharge passages 71 and 72 are formed as through holes inside the planetary carrier pin 123.

[0059] As shown in Figures 11 and 12, the discharge channel 71 has a first portion 711 and a second portion 712. The first portion 711 is formed from an inlet 71a located on the outer circumferential surface 23a toward the central axis 23c of the planetary carrier pin 123. The first portion 711 is formed perpendicular to the central axis O. The inlet 71a opens into space S. The inlet 71a opens toward the central axis O. The inlet 71a is located in the portion of the outer circumferential surface 23a of the planetary carrier pin 23 that is closest to the central axis O in the circumferential direction. The second portion 712 is formed from the end of the first portion 711 on the central axis 23c side toward the outlet 71b located on the first end face 41e. The second portion 712 is inclined away from the central axis 23c as it moves toward the first direction A1. The outlet 71b opens toward the first end face 41e. Furthermore, the discharge channel 71 is formed to avoid the pin supply channel 43 so as not to intersect with it.

[0060] The discharge channel 72 has a first portion 721 and a second portion 722. The first portion 721 is formed from an inlet 72a located on the outer circumferential surface 23a toward the central axis 23c of the planetary carrier pin 123. The first portion 721 is formed perpendicular to the central axis O. The inlet 72a opens into space S. The inlet 72a opens toward the central axis O. The inlet 72a is located in the portion of the outer circumferential surface 23a of the planetary carrier pin 23 that is closest to the central axis O in the circumferential direction. The second portion 722 is formed from the end of the first portion 721 on the central axis 23c side toward the outlet 72b located on the second end face 42e. The second portion 722 is inclined away from the central axis 23c as it moves toward the first direction A1. The outlet 72b opens toward the second end face 42e.

[0061] It is formed from an inlet 72a located on the outer circumferential surface 23a to an outlet 72b located on the second end face 42e. The inlet 72a opens toward the central axis O. The inlet 72a is located in the part of the outer circumferential surface 23a of the planetary carrier pin 23 that is closest to the central axis O in the circumferential direction.

[0062] The inlet 71a of the discharge channel 71, the inlet 72a of the discharge channel 72, and the outlet 43b of the pin supply channel 43 are arranged on a straight line parallel to the central axis 23c. The inlets 71a, 43b, and 72a are arranged in this order toward the second direction A2.

[0063] Similar to Embodiment 1, the lubricating oil supplied to the space S through the pin supply channel 43 is discharged from the space S to the outside of the planetary carrier pin 123 through the discharge channels 71 and 72 (see solid arrows in Figure 11). The lubricating oil discharged to the outside of the planetary gear 22 is returned to the tank 12 through the discharge channel 75 connecting the housing 29 and the tank 12. The dotted arrows shown in Figure 11 and Figure 13, which will be described later, indicate the discharge of lubricating oil from the gap necessary for assembling the planetary gear 22 and the washer 30, similar to the dotted arrows in Figure 9.

[0064] (Features, etc.) In the planetary gear mechanism 11 of this embodiment, the planetary carrier pin 123 has discharge passages 71 and 72 that discharge lubricating oil from the space S in which the needle bearing 24 is located. As a result, the lubricating oil supplied to the space S is discharged through the discharge passages 71 and 72, which suppresses the accumulation of excess lubricating oil in the space S and reduces agitation loss.

[0065] Furthermore, since the inlets 71a of the discharge channel 71 and 72a of the discharge channel 72 are positioned facing the central axis O of the planetary carrier 25, they open to the area R2 (see Figure 10) where the lubricating oil accumulates. As a result, the lubricating oil can be discharged from the area R2 where it tends to accumulate, allowing for efficient discharge of the lubricating oil and reducing agitation losses.

[0066] (Embodiment 3) Next, the planetary gear mechanism 211 of Embodiment 3 will be described. Compared to the planetary gear mechanism 111 of Embodiment 2, the planetary gear mechanism 211 of Embodiment 3 has a different configuration of discharge passages 71 and 72 formed in the planetary carrier pin 123. In Embodiment 3, the differences from Embodiment 2 will be described, and similar configurations will not be described.

[0067] (composition) Figure 13 is a partially enlarged view of the planetary gear mechanism 211 of this third embodiment. Similar to Figures 9 and 11, Figure 13 shows portion E of Figure 7. The planetary gear mechanism 211 of this third embodiment has a planetary carrier pin 223 with discharge passages 81 and 82 formed thereon. The planetary carrier pin 223 has the same configuration as the planetary carrier pin 123 of the second embodiment, except that discharge passages 81 and 82 are formed thereon instead of discharge passages 71 and 72.

[0068] The discharge channels 81 and 82 discharge lubricating oil from the space S to the outside of the planetary carrier pin 223. The discharge channels 81 and 82 are formed in a groove shape on the outer circumferential surface 23a of the planetary carrier pin 223. Figure 14 is a perspective view of the planetary carrier pin 223. Figure 15 is a partial cross-sectional perspective view of the planetary gear mechanism 211.

[0069] As shown in Figures 14 and 15, the discharge channel 81 is formed around the outer circumferential surface 23a. Since the discharge channel 81 is a groove, lubricating oil can flow into it from any point. However, due to the centrifugal force caused by the rotation of the planetary gear 22 and planetary carrier 25, the portion of the discharge channel 81 facing the central axis O becomes the inlet 81a, and the lubricating oil mainly flows into this portion. The portion of the discharge channel 81 facing the opposite side of the central axis O becomes the outlet 81b, and the lubricating oil is discharged to the outside of the planetary carrier pin 223. The outlet 81b is located on the first direction A1 side than the inlet 81a. Grooves are formed counterclockwise and clockwise from the inlet 81a toward the outlet 81b. The outlet 81b opens onto the outer circumferential surface 41a of the first end 41 inserted into the first carrier disk 51. The outlet 81b faces the carrier discharge channel 83 (carrier channel) formed in the planetary carrier 25. The carrier discharge channel 83 is formed from the inner circumferential surface 51a to the outer circumferential surface 51c of the first carrier disk 51. The carrier discharge channel 83 is positioned perpendicular to the central axis 23c.

[0070] The discharge channel 82 is formed around the outer surface 23a. Since the discharge channel 82 is a groove, lubricating oil can flow into it from any point. However, due to the centrifugal force caused by the rotation of the planetary gear 22 and planetary carrier 25, the portion of the discharge channel 82 facing the central axis O becomes the inlet 82a, and the lubricating oil mainly flows into this portion. The portion of the discharge channel 82 facing the opposite side of the central axis O becomes the outlet 82b, and the lubricating oil is discharged to the outside of the planetary carrier pin 223. The outlet 82b is located on the second direction A2 side than the inlet 82a. Grooves are formed counterclockwise and clockwise from the inlet 82a toward the outlet 82b. The outlet 82b opens onto the second end face 42e.

[0071] Similar to Embodiment 1, the lubricating oil supplied to the space S through the pin supply channel 43 flows into the discharge channels 81 and 82 by centrifugal force from the rotation of the planetary gear 22 and planetary carrier 25, and is discharged from the space S to the outside of the planetary carrier pin 223 (see solid arrow in Figure 13). The lubricating oil in the space S flows into the inlet 81a of the discharge channel 81, flows out from the outlet 81b, and flows into the carrier discharge channel 83. The lubricating oil that flows into the carrier discharge channel 83 is discharged to the outside of the planetary carrier 25. The lubricating oil in the space S also flows into the inlet 82a of the discharge channel 82, flows out from the outlet 82b, and is discharged to the outside of the planetary carrier 25. The lubricating oil discharged to the outside of the planetary carrier 25 is returned to the tank 12 through the discharge channel 75 connecting the housing 29 and the tank 12.

[0072] (Features, etc.) In the planetary gear mechanism 211 of this embodiment, the planetary carrier pin 223 has discharge passages 81 and 82 that discharge lubricating oil from the space S in which the needle bearing 24 is located. As a result, the lubricating oil supplied to the space S is discharged through the discharge passages 71 and 72, which suppresses the accumulation of excess lubricating oil in the space S and reduces agitation loss.

[0073] Furthermore, since the inlet 81a of the discharge channel 81 and the inlet 82a of the discharge channel 82 are positioned facing the central axis O of the planetary carrier 25, they open to the area R2 where the lubricating oil accumulates. As a result, the lubricating oil can be discharged from the area R2 (Figure 10) where it tends to accumulate, allowing for efficient discharge of the lubricating oil and reducing agitation losses.

[0074] <Other Embodiments> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. In particular, the multiple embodiments and modifications described herein can be arbitrarily combined as needed.

[0075] (A) In Embodiment 1, discharge passages 35 and 36 are provided in the planetary gear 22; in Embodiment 2, discharge passages 71 and 72 are provided in the planetary carrier pin 123; and in Embodiment 3, discharge passages 81 and 82 are provided in the planetary carrier pin 223. However, all or part of the three embodiments may be combined.

[0076] (B) In the above embodiment 1, a recess 33a is provided on the first side surface 33, and the discharge channel 35 is formed up to the recess 33a, but the recess 33a does not have to be provided on the first side surface 33. Also, a recess 34a is provided on the second side surface 34, and the discharge channel 36 is formed up to the recess 34a, but the recess 34a does not have to be provided on the second side surface 34.

[0077] (C) In Embodiment 1 above, the planetary gear 22 is provided with four discharge passages 35 and four discharge passages 36, but it is not limited to four of each; there may be three or fewer, or five or more. The number of discharge passages 35 and discharge passages 36 may be different. Also, only one of the discharge passages 35 or discharge passages 36 may be provided. In Embodiment 2 above, the planetary carrier pin 123 is provided with two discharge passages 71 and 72, but it is not limited to two; there may be one or three or more. In Embodiment 3 above, the planetary carrier pin 223 is provided with two discharge passages 81 and 82, but it is not limited to two; there may be one or three or more.

[0078] (D) In the above embodiment 3, the carrier discharge channel 83 is formed to penetrate the first carrier disk 51 from the inner circumferential surface 51a to the outer circumferential surface 51c, but it may be formed not only to the outer circumferential surface 51c but also to the side surface 51d (see Figure 13). The side surface 51d is the surface of the first carrier disk 51 facing the first direction A1 side.

[0079] (E) In the above embodiment, one needle bearing 24 is provided in the direction along the central axis O, but multiple needle bearings may be provided.

[0080] (F) In the above embodiment, a needle bearing 24 is used as an example of a bearing, but it is not limited to this, and for example, a roll bearing or the like may be used.

[0081] (G) In the above embodiment, three planetary gears 22, 122 are arranged, but the embodiment is not limited to this, and there may be four or more.

[0082] (H) In the above embodiment, the ring gear 26 is fixed to the housing 29, the sun gear 21 and planetary gear 22 rotate relative to the housing 29, power is input to the sun gear 21 and output from the planetary carrier 25, but it is not limited to this. For example, the planetary carrier 25 may be fixed to the housing 29, the sun gear 21 and ring gear 26 may rotate, and power may be output from the ring gear.

[0083] (I) The work machine 1 in the above embodiment can be exemplified by a dump truck, wheel loader, or forklift equipped with front and rear tires, but is not limited to these; it can also include shovels and bulldozers with tracks.

[0084] (J) The drive system 2 of the work machine 1 in the above embodiment 1 is electrically driven, but is not limited to this, and may include, for example, an internal combustion engine, or a hybrid of an internal combustion engine and an electric motor. Figure 16 is a schematic diagram showing the drive system 102 of a work machine 101 that uses an internal combustion engine. The drive system 102 of the work machine 101 includes an engine 103, a torque converter 104, a transmission 105, a transfer case 106, axles 107a and 107b, a pair of rear tires 108, and a pair of front tires 109. The engine 103 is, for example, a diesel engine. The driving force generated by the engine 103 is transmitted to the torque converter 104. The torque converter 104 transmits the driving force generated by the engine 103 to the transmission 105.

[0085] The transmission 105 reduces the driving force of the engine 103, which is transmitted via the torque converter 104, and transmits it to the transfer case 106. The planetary gear mechanism 11 in this embodiment is used, for example, as a reduction gear for the transmission 105.

[0086] The transfer case 106 distributes the driving force transmitted from the transmission 105 to the front and rear axles 107a and 107b. A pair of rear tires 108 are connected to the rear axle 107a. The pair of rear tires 108 are rotated by the power from the engine 103 distributed to the rear axle 107a. A pair of front tires 109 are connected to the front axle 107b. The pair of front tires 109 are rotated by the power from the engine 103 distributed to the front axle 107b.

[0087] (K) In the above embodiment, the planetary gear mechanism 11 is applied to the work machine 1, but it is not limited to work machines and can be applied to any configuration that has planetary gears. [Industrial applicability]

[0088] According to this disclosure, a planetary gear mechanism capable of reducing stirring losses can be provided. [Explanation of Symbols]

[0089] 11: Planetary gear mechanism 22: Planetarium 24: Needle bearing 25: Planetary Carrier 35: Discharge channel 36: Discharge channel S: Space

Claims

1. Planetary gear and, A shaft member that rotatably supports the aforementioned planetary gear, A bearing is disposed between the shaft member and the planetary gear, The system comprises planetary carriers that support both ends of the shaft member, The planetary gear has a discharge channel for discharging lubricating oil from the space in which the bearing is located. Planetary gear mechanism.

2. The aforementioned planetary gear is The inner circumferential surface that contacts the bearing, Outer surface including tooth shape, It further has a side surface disposed between the inner circumferential surface and the outer circumferential surface, The discharge channel is formed to penetrate from the inner circumferential surface to the side surface, The planetary gear mechanism according to claim 1.

3. Planetary gear and, A shaft member that rotatably supports the aforementioned planetary gear, A bearing is disposed between the shaft member and the planetary gear, The system comprises planetary carriers that support both ends of the shaft member, The shaft member has a discharge channel for discharging lubricating oil from the space in which the bearing is located. Planetary gear mechanism.

4. The aforementioned discharge channel is formed to penetrate the inside of the shaft member, The planetary gear mechanism according to claim 3.

5. The discharge channel is formed in the shape of a groove on the outer circumferential surface of the shaft member that contacts the bearing. The planetary gear mechanism according to claim 3.

6. The inlet of the lubricating oil in the discharge channel is located on the outer circumferential surface of the shaft member on the side of the central axis of the planetary carrier. The planetary gear mechanism according to claim 3.

7. The outlet for the lubricating oil in the discharge channel is located on the end face of the bearing. The planetary gear mechanism according to claim 3.

8. The aforementioned planetary carrier is A first carrier disk supporting the first end of the shaft member, The system further includes a second carrier disk that supports the second end of the shaft member opposite to the first end and is positioned opposite the first carrier disk, The first carrier disk has a carrier channel formed to penetrate from the inner circumferential surface that contacts the shaft member to the outer circumferential surface or side surface, The aforementioned discharge channel is connected to the aforementioned carrier channel. The planetary gear mechanism according to claim 3.

Images