Turning reduction gear and work machine

Abstract

This turning reduction gear comprises a first planetary gear mechanism, a case, and an oil guide. The first planetary gear mechanism includes a first sun gear, a first planetary gear meshing with the first sun gear, a first carrier engaged with the first planetary gear, and a first ring gear meshing with the first planetary gear. The case accommodates the first planetary gear mechanism. The oil guide is disposed below the first ring gear and protrudes radially inward from the inner surface of the case.

Description

Slewing reducer and working machine

[0001] The present disclosure relates to a slewing reducer and a working machine.

[0002] A slewing reducer decelerates and transmits the rotation of a power source such as a motor. For example, the slewing reducer of Patent Document 1 includes a plurality of planetary gear reduction mechanisms, a housing, and an output shaft. The plurality of planetary gear reduction mechanisms are arranged in the vertical direction. The plurality of planetary gear reduction mechanisms are arranged within the housing. The output shaft is arranged below the plurality of planetary gear reduction mechanisms. A motor is arranged above the slewing reducer. The rotation from the motor is decelerated by the plurality of planetary gear reduction mechanisms and transmitted to the output shaft.

[0003] Japanese Patent Application Laid-Open No. 2002-201666

[0004] In the above slewing reducer, the housing is filled with lubricating oil. When the plurality of planetary gear reduction mechanisms rotate, a flow of lubricating oil occurs within the housing. As a result, when the lubricating oil flows between the plurality of planetary gear mechanisms, each of the plurality of planetary gear mechanisms receives a force in the vertical direction from the lubricating oil. Such a force affects the power transmission efficiency of the planetary gear mechanism. The object of the present disclosure is to improve the power transmission efficiency of the planetary gear mechanism by controlling the flow of lubricating oil in the slewing reducer.

[0005] The slewing reducer according to one aspect of the present disclosure includes a first planetary gear mechanism, a case, and an oil guide. The first planetary gear mechanism includes a first sun gear, a first planetary gear that meshes with the first sun gear, a first carrier that engages with the first planetary gear, and a first ring gear that meshes with the first planetary gear. The case houses the first planetary gear mechanism. The oil guide is arranged below the first ring gear and protrudes radially inward from the inner surface of the case.

[0006] In the slewing reducer according to this aspect, the flow of lubricating oil within the case is controlled by the oil guide. Therefore, the force exerted on the first planetary gear mechanism by the lubricating oil flowing around the first planetary gear mechanism can be adjusted. Thereby, the power transmission efficiency of the first planetary gear mechanism can be improved.

[0007] A work machine according to another aspect of this disclosure comprises a traveling body, a slewing body, a motor, and the slewing reduction gear described above. The slewing body is rotatably supported on the traveling body. The slewing reduction gear is connected to the motor. The slewing reduction gear rotates the slewing body by the rotation of the motor.

[0008] According to this disclosure, in a slewing reduction gear, the power transmission efficiency of the planetary gear mechanism is improved by controlling the flow of lubricating oil.

[0009] This is a side view of a work machine according to an embodiment. This is a cross-sectional view of the motor and the slewing reducer. This is an enlarged cross-sectional view of the slewing reducer. This is a cross-sectional view of the gear case and oil guide as seen from the axial direction. This is a bottom view of the first carrier. This is a cross-sectional view of the first carrier taken along line VI-VI in Figure 5. This is an enlarged cross-sectional view of the slewing reducer according to another embodiment. This is an enlarged cross-sectional view of the slewing reducer according to the first modified example. This is a bottom view of the first carrier according to the second modified example. This is a cross-sectional view of the first carrier taken along line X-X in Figure 9 according to the second modified example. This is a view of the gear case and oil guide taken along the axial direction according to the third modified example. This is a view of the gear case and oil guide taken along the axial direction according to the fourth modified example.

[0010] The following description of the work machine according to the embodiment will be made with reference to the drawings. Figure 1 is a side view of the work machine 1. In this embodiment, the work machine 1 is an excavator such as a hydraulic excavator or an electric excavator.

[0011] As shown in Figure 1, the work machine 1 includes a work implement 2, a slewing body 3, and a traveling body 4. The work implement 2 is attached to the slewing body 3. The work implement 2 is movably mounted to the slewing body 3. The work implement 2 includes a boom 11, an arm 12, and a bucket 13.

[0012] The slewing body 3 is rotatably supported on the running body 4. The slewing body 3 is rotatable around the pivot center C1. A cab 5 is positioned on the slewing body 3. The running body 4 includes tracks 6. Alternatively, the running body 4 may be equipped with wheels and tires. The boom 11 is rotatably mounted on the slewing body 3.

[0013] The working machine 1 comprises a swing circle 7, a motor 8, and a slewing reduction gear 9. The swing circle 7 has an inner ring and an outer ring, the outer ring being fixed to the traveling body 4, and the inner ring being fixed to the slewing body 3. However, the inner ring may be fixed to the traveling body 4 and the outer ring to the slewing body 3. The motor 8 is, for example, an electric motor. Alternatively, the motor 8 may be a hydraulic motor. The slewing reduction gear 9 is connected to the motor 8 and the swing circle 7. The slewing reduction gear 9 is fixed to the slewing body 3. The slewing reduction gear 9 transmits the rotation of the motor 8 to the swing circle 7. As a result, the slewing body 3 rotates around the pivot point.

[0014] Figure 2 is a cross-sectional view of the motor 8 and the slewing reduction gear 9. Figure 3 is an enlarged cross-sectional view of the slewing reduction gear 9. As shown in Figures 2 and 3, the motor 8 includes a motor case 14 and a motor shaft 15. The motor shaft 15 extends in the vertical direction. The motor shaft 15 protrudes downward from the motor case 14.

[0015] The slewing reduction gear 9 is located below the motor 8. The slewing reduction gear 9 supports the motor 8. The slewing reduction gear 9 comprises a case 20, a first planetary gear mechanism 21, a second planetary gear mechanism 22, and an output shaft 24. The case 20 houses the first planetary gear mechanism 21, the second planetary gear mechanism 22, and the output shaft 24. The motor shaft 15, the first planetary gear mechanism 21, the second planetary gear mechanism 22, and the output shaft 24 are arranged coaxially. The axes of the motor shaft 15, the first planetary gear mechanism 21, the second planetary gear mechanism 22, and the output shaft 24 extend in the vertical direction.

[0016] The first planetary gear mechanism 21 is connected to the motor shaft 15 and the second planetary gear mechanism 22 so as to be movable in the vertical direction. The first planetary gear mechanism 21 reduces the rotation of the motor shaft 15 and transmits it to the second planetary gear mechanism 22. The first planetary gear mechanism 21 includes a first sun gear 26, a first planetary gear 27, a first carrier 28, and a first ring gear 37.

[0017] The first sun gear 26 is located below the motor shaft 15. The first sun gear 26 is connected to the motor shaft 15. The first sun gear 26 is connected to the motor shaft 15 in a way that it is immobile and movable in the vertical direction. The first sun gear 26 is coupled to the motor shaft 15, for example, by a spline. The first sun gear 26 rotates integrally with the motor shaft 15. The first planetary gear 27 is located on the outer circumference of the first sun gear 26. The first planetary gear 27 meshes with the first sun gear 26. The first planetary gear 27 is capable of revolving around the first sun gear 26. As shown in Figure 3, the first planetary gear 27 is supported on the first carrier 28 via a bearing 29 and a first support shaft 30 so that it can rotate. The first carrier 28 is engaged with the first planetary gear 27. The first carrier 28 rotates around the first sun gear 26 along with the revolving of the first planetary gear 27. The first ring gear 37 meshes with the first planetary gear 27.

[0018] The second planetary gear mechanism 22 is located below the first planetary gear mechanism 21. The second planetary gear mechanism 22 is connected to the first planetary gear mechanism 21 and the output shaft 24 so as to be movable in the vertical direction. The second planetary gear mechanism 22 reduces the rotation of the first planetary gear mechanism 21 and transmits it to the output shaft 24. The second planetary gear mechanism 22 includes a second sun gear 31, a second planetary gear 32, a second carrier 33, and a second ring gear 38.

[0019] The second sun gear 31 is positioned below the first sun gear 26. The second sun gear 31 slidably supports the first sun gear 26 via a first sliding member 41. The first sliding member 41 is sandwiched between the first sun gear 26 and the second sun gear 31. The first sliding member 41 is, for example, a washer. The first carrier 28 is connected to the second sun gear 31 in a non-rotatable and vertically movable manner. The first carrier 28 is coupled to the second sun gear 31, for example, by a spline. The second sun gear 31 rotates integrally with the first carrier 28.

[0020] The second planetary gear 32 is positioned on the outer circumference of the second sun gear 31. The second planetary gear 32 meshes with the second sun gear 31. The second planetary gear 32 is capable of revolving around the second sun gear 31. As shown in Figure 3, the second planetary gear 32 is supported on the second carrier 33 via a bearing 34 and a second support shaft 35 so that it can rotate. The second carrier 33 is engaged with the second planetary gear 32. The second carrier 33 rotates around the second sun gear 31 as the second planetary gear 32 revolves. The second ring gear 38 is positioned below the first ring gear 37. The second ring gear 38 meshes with the second planetary gear 32.

[0021] The case 20 includes a gear case 23 and a main body case 25. The gear case 23 is positioned above the main body case 25. The gear case 23 is fixed to the main body case 25. The gear case 23 includes a cylindrical portion 36. The first ring gear 37 and the second ring gear 38 are provided on the inner surface of the cylindrical portion 36. The first ring gear 37 and the second ring gear 38 may be separate from the gear case 23, or they may be fixed to the inner surface of the gear case 23. Alternatively, the first ring gear 37 and the second ring gear 38 may be formed integrally with the gear case 23.

[0022] The output shaft 24 extends in the vertical direction. The output shaft 24 is located below the second planetary gear mechanism 22. The output shaft 24 is located below the second sun gear 31. The output shaft 24 slidably supports the second sun gear 31 via a second sliding member 42. The second sliding member 42 is sandwiched between the second sun gear 31 and the output shaft 24. The second sliding member 42 is, for example, a bolt having a spherical head. Alternatively, the second sliding member 42 may be a washer.

[0023] The second carrier 33 is connected to the output shaft 24 in a way that it is immobile and movable in the vertical direction. The second carrier 33 is coupled to the output shaft 24, for example, by a spline. The output shaft 24 rotates integrally with the second carrier 33. As shown in Figure 2, the lower end of the output shaft 24 protrudes downward from the main body case 25. The space between the output shaft 24 and the main body case 25 is sealed by an oil seal 44. The output shaft 24 includes a pinion gear 43. The pinion gear 43 is provided at the lower end of the output shaft 24. The swing circle 7 described above has an internal gear. The pinion gear 43 meshes with the internal gear of the swing circle 7. However, the swing circle 7 may also have an external gear, and the pinion gear 43 may mesh with the external gear of the swing circle 7.

[0024] The main body case 25 rotatably supports the output shaft 24 via bearings 45 and 46. The main body case 25 is located below the gear case 23. The gear case 23 is fixed to the main body case 25. The main body case 25 is fixed to the slewing body 3 described above. The main body case 25 and the gear case 23 are filled with lubricating oil. The first planetary gear mechanism 21, the second planetary gear mechanism 22, and the output shaft 24 are lubricated by the lubricating oil filled in the main body case 25 and the gear case 23. In Figure 2, the dashed line L1 indicates the height of the lubricating oil level when the slewing reduction gear 9 is stationary. As shown in Figure 2, the oil level L1 is located above the first planetary gear mechanism 21.

[0025] In the slewing reduction gear 9, the rotation of the motor shaft 15 is transmitted to the output shaft 24 via the first sun gear 26, the first planetary gear 27, the first carrier 28, the second sun gear 31, the second planetary gear 32, and the second carrier. This causes the output shaft 24 to rotate. The rotation of the output shaft 24 is transmitted to the swing circle 7 via the pinion gear 43. This causes the slewing body 3 to slewing relative to the traveling body 4.

[0026] The rotational speed of the second sun gear 31 is less than that of the first sun gear 26. Therefore, due to the difference in rotational speeds between the first sun gear 26 and the second sun gear 31, the first sun gear 26 slides against the first sliding member 41. Also, the rotational speed of the output shaft 24 is less than that of the second sun gear 31. Therefore, due to the difference in rotational speeds between the output shaft 24 and the second sun gear 31, the second sun gear 31 slides against the second sliding member 42.

[0027] The slewing reduction gear 9 includes an oil guide 50. The oil guide 50 protrudes radially inward from the inner surface of the gear case 23. The oil guide 50 is positioned below the first ring gear 37. The oil guide 50 is positioned below the first carrier 28. The oil guide 50 is positioned above the second ring gear 38. The oil guide 50 is positioned above the second carrier 33. The oil guide 50 is positioned between the first ring gear 37 and the second ring gear 38. In the radial direction, the oil guide 50 is positioned opposite the space between the first carrier 28 and the second carrier 33. Figure 4 is a cross-sectional view of the gear case 23 and the oil guide 50 as seen from the axial direction. As shown in Figure 4, the oil guide 50 has an annular shape when viewed from the axial direction of the gear case 23.

[0028] The oil guide 50 is provided to allow lubricating oil to flow between the first carrier 28 and the second carrier 33. The upper surface of the oil guide 50 is inclined to guide the lubricating oil between the first carrier 28 and the second carrier 33. The upper surface of the oil guide 50 has a shape that slopes downward toward the radially inward direction. The upper surface of the oil guide 50 has an arc-shaped cross-section whose center is located radially inward and above the oil guide 50. When lubricating oil flows between the first carrier 28 and the second carrier 33, a force is generated that lifts the first carrier 28. As a result, the surface pressure between the first sun gear 26 and the first sliding member 41 is reduced, thereby reducing the rotational resistance of the first planetary gear mechanism 21. Furthermore, as a result, the surface pressure between the second sun gear 31 and the second sliding member 42 is reduced, thereby reducing the rotational resistance of the second planetary gear mechanism 22. As a result, the power transmission efficiency of the slewing reduction gear 9 is improved.

[0029] Figure 5 is a bottom view of the first carrier 28. Figure 6 is a cross-sectional view of the first carrier 28 along the line VI-VI in Figure 5. As shown in Figures 5 and 6, the first carrier 28 includes shaft holes 51A, 51B, 51C and recesses 52A, 52B, 52C. The shaft holes 51A, 51B, 51C penetrate the first carrier 28 in the vertical direction. The first support shaft 30 described above is passed through the shaft holes 51A, 51B, 51C.

[0030] The recesses 52A, 52B, and 52C are provided on the lower surface of the first carrier 28. The recesses 52A, 52B, and 52C are recessed upward from the lower surface of the first carrier 28. The recesses 52A, 52B, and 52C are located between the shaft holes 51A, 51B, and 51C in the circumferential direction of the first carrier 28, respectively. The recesses 52A, 52B, and 52C receive lubricating oil flowing downward from the first carrier 28. As a result, the first carrier 28 becomes more susceptible to the lifting force from the lubricating oil flowing between the first carrier 28 and the second carrier 33.

[0031] 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.

[0032] The work machine 1 is not limited to an excavator, but may be other machines such as a crane. The configuration of the slewing reduction gear 9 is not limited to that of the above embodiment and may be changed. For example, the number of planetary gear mechanisms in the slewing reduction gear 9 is not limited to two, but may be more than two. Alternatively, as shown in Figure 7, the number of planetary gear mechanisms in the slewing reduction gear 9 may be one. In this case, the oil guide 50 may be positioned radially opposite the space between the first carrier 28 and the main body case 25. The oil guide 50 may protrude from the inner surface of the main body case 25. Alternatively, as in the above embodiment, the oil guide 50 may protrude from the inner surface of the gear case 23. In Figure 7, the same reference numerals are used for components corresponding to the configuration of the above embodiment.

[0033] The configuration of the oil guide 50 is not limited to that of the embodiment described above and may be modified. For example, the oil guide 50 may be provided in such a way that it obstructs the flow of lubricating oil between the first carrier 28 and the second carrier 33. Figure 8 is an enlarged cross-sectional view of the slewing reduction gear 9 according to the first modified example. As shown in Figure 8, the oil guide 50 may be positioned above the space between the first carrier 28 and the second carrier 33. The oil guide 50 may be positioned facing the first carrier 28 in the radial direction. This reduces the flow rate of lubricating oil flowing between the first carrier 28 and the second carrier 33. As a result, the lifting force acting on the first carrier 28 is suppressed, thereby improving the power transmission efficiency of the slewing reduction gear 9.

[0034] The cross-sectional shape of the upper surface of the oil guide 50 may extend radially inward without being inclined vertically, as shown in Figure 8. The upper and lower surfaces of the oil guide 50 may have a tapered shape. The center of the arc-shaped circle on the upper surface of the oil guide 50 may be located radially outward and below the oil guide 50.

[0035] The configuration of the first carrier 28 is not limited to that of the embodiment described above and may be modified. For example, the number of recesses is not limited to three; it may be fewer than three or more than three. Recesses 52A, 52B, and 52C may be omitted.

[0036] Figure 9 is a bottom view of the first carrier 28 according to a second modification. Figure 10 is a cross-sectional view of the first carrier 28 according to the second modification, taken along the line X-X in Figure 9. As shown in Figures 9 and 10, the first carrier 28 may include holes 54 that penetrate in the vertical direction. In the drawings, only some of the multiple holes 54 are labeled with reference numeral 54, and the reference numerals for the other holes 54 are omitted. In this case, lubricating oil that flows between the first carrier 28 and the second carrier 33 can pass through the holes 54 and escape from between the first carrier 28 and the second carrier 33. This allows the lifting force acting on the first carrier 28 to be adjusted.

[0037] Figure 11 is a view of the gear case 23 and oil guide 50 according to a third modified example, as seen from the axial direction. As shown in Figure 11, the oil guide 50 is not limited to annular shape, but may be divided into a plurality of guide sections 55A, 55B, 55C. The plurality of guide sections 55A, 55B, 55C may be arranged apart from each other in the circumferential direction. By dividing the oil guide 50 into a plurality of guide sections 55A, 55B, 55C, the lifting force acting on the first carrier 28 can be adjusted.

[0038] Figure 12 is a view of the gear case 23 and oil guide 50 according to the fourth modified example, as seen from the axial direction. As shown in Figure 12, the multiple guide portions 55A, 55B, and 55C are not limited to arc shapes, but may also be straight. The number of multiple guide portions 55A, 55B, and 55C is not limited to three, but may be fewer than three or more than three.

[0039] According to this disclosure, in a slewing reduction gear, the power transmission efficiency of the planetary gear mechanism is improved by controlling the flow of lubricating oil.

[0040] 4: Running body, 3: Rotating body, 8: Motor, 9: Rotating reduction gear, 21: First planetary gear mechanism, 22: Second planetary gear mechanism, 23: Gear case, 24: Output shaft, 26: First sun gear, 27: First planetary gear, 28: First carrier, 31: Second sun gear, 32: Second planetary gear, 33: Second carrier, 37: First ring gear, 38: Second ring gear, 50: Oil guide, 52A, 52B, 52C: Recess, 54: Hole

Claims

1. A slewing reduction gear comprising: a first planetary gear mechanism including a first sun gear, a first planetary gear meshing with the first sun gear, a first carrier engaging with the first planetary gear, and a first ring gear meshing with the first planetary gear; a case housing the first planetary gear mechanism; and an oil guide positioned below the first ring gear and projecting radially inward from the inner surface of the case.

2. The slewing reduction gear according to claim 1, wherein the oil guide is located below the first carrier.

3. The slewing reduction gear according to claim 1, further comprising: a second sun gear slidably supporting the first sun gear; a second planetary gear meshing with the second sun gear; a second carrier engaging with the second planetary gear; and a second ring gear meshing with the second planetary gear, the second planetary gear mechanism being disposed below the first planetary gear mechanism, wherein the case houses the second planetary gear mechanism.

4. The slewing reduction gear according to claim 3, wherein the oil guide is positioned above the second ring gear.

5. The slewing reduction gear according to claim 3, wherein the oil guide is positioned above the second carrier.

6. The slewing reduction gear according to claim 3, wherein the oil guide is positioned radially opposite the space between the first carrier and the second carrier.

7. The slewing reduction gear according to claim 3, wherein the first ring gear and the second ring gear are provided on the inner surface of the case, and the oil guide is positioned between the first ring gear and the second ring gear.

8. The slewing reduction gear according to claim 1, wherein the oil guide is arranged facing the first carrier in the radial direction.

9. The swivel reduction gear according to claim 1, wherein the oil guide has an annular shape when viewed from the axial direction of the case.

10. The slewing reduction gear according to claim 1, wherein the oil guide includes a plurality of guide portions arranged apart from each other in the circumferential direction when viewed from the axial direction of the case.

11. The slewing reduction gear according to claim 1, wherein the lower surface of the first carrier includes a recess for receiving lubricating oil flowing in below the first carrier.

12. The slewing reduction gear according to claim 1, wherein the first carrier includes a hole that penetrates in the vertical direction.

13. The slewing reduction gear according to claim 3, wherein the oil guide is provided to allow lubricating oil to flow between the first carrier and the second carrier.

14. The slewing reduction gear according to claim 3, wherein the oil guide is provided to obstruct the flow of lubricating oil between the first carrier and the second carrier.

15. The slewing reduction gear according to claim 3, further comprising an output shaft positioned below the second planetary gear mechanism and slidably supporting the second sun gear.

16. The slewing reduction gear according to claim 1, wherein the upper surface of the oil guide has a shape that slopes downward toward the radially inward direction.

17. A working machine comprising: a traveling body; a slewing body rotatably supported on the traveling body; a motor; and a slewing reduction gear connected to the motor and rotating the slewing body by the rotation of the motor, wherein the slewing reduction gear includes a first planetary gear mechanism including a first sun gear; a first planetary gear meshing with the first sun gear; a first carrier engaging with the first planetary gear; and a first ring gear meshing with the first planetary gear; a case housing the first planetary gear mechanism; and an oil guide positioned below the first ring gear and projecting radially inward from the inner surface of the case.

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