Swivel reduction gear and work machine

Abstract

In a slewing reduction gear, controlling the flow of lubricating oil improves the power transmission efficiency of the planetary gear mechanism. [Solution] The slewing 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 engaging with the first planetary gear, and a first ring gear meshing with the first planetary gear. The case houses the first planetary gear mechanism. The oil guide is positioned below the first ring gear and protrudes radially inward from the inner surface of the case.

Description

Technical Field

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

Background Art

[0002] A swing reducer decelerates and transmits the rotation of a power source such as a motor. For example, the swing 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 in the housing. The output shaft is arranged below the plurality of planetary gear reduction mechanisms. A motor is arranged above the swing reducer. The rotation from the motor is decelerated by the plurality of planetary gear reduction mechanisms and transmitted to the output shaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above swing reducer, the housing is filled with lubricating oil. When the plurality of planetary gear reduction mechanisms rotate, a flow of lubricating oil occurs in the housing. As a result, when the lubricating oil flows into the space 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 swing reducer.

Means for Solving the Problems

[0005] A slewing speed reducer according to one aspect of the present disclosure 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 engaging with the first planetary gear, and a first ring gear meshing with the first planetary gear. The case houses the first planetary gear mechanism. The oil guide is positioned below the first ring gear and protrudes radially inward from the inner surface of the case.

[0006] In the slewing reduction gear according to this embodiment, the flow of lubricating oil within the case is controlled by an oil guide. Therefore, the force exerted on the first planetary gear mechanism by the lubricating oil flowing around it can be adjusted. This improves the power transmission efficiency of the first planetary gear mechanism.

[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. [Effects of the Invention]

[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. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view of the work machine according to the embodiment. [Figure 2] This is a cross-sectional view of the motor and the slewing reduction gear. [Figure 3] This is an enlarged cross-sectional view of a slewing speed reducer. [Figure 4] This is a cross-sectional view of the gear case and oil guide, seen from the axial direction. [Figure 5] This is a bottom view of the first carrier. [Figure 6] This is a cross-sectional view of the first carrier from VI-VI in Figure 5. [Figure 7]This is an enlarged cross-sectional view of a swing reduction gear according to another embodiment. [Figure 8] This is an enlarged cross-sectional view of a swing reduction gear according to the first modified example. [Figure 9] This is a bottom view of the first carrier relating to the second modified example. [Figure 10] This is a cross-sectional view of the first carrier according to the second modified example, shown as XX in Figure 9. [Figure 11] This is a view of the gear case and oil guide according to the third modified example, seen from the axial direction. [Figure 12] This is a view of the gear case and oil guide according to the fourth modified example, seen from the axial direction. [Modes for carrying out the invention]

[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 includes a swing circle 7, a motor 8, and a swing reduction gear 9. The swing circle 7 has an inner ring and an outer ring, and the outer ring is fixed to the traveling body 4. The inner ring is fixed to the revolving body 3. However, the inner ring may be fixed to the traveling body 4 and the outer ring may be fixed to the revolving body 3. The motor 8 is, for example, an electric motor. Alternatively, the motor 8 may be a hydraulic motor. The swing reduction gear 9 is connected to the motor 8 and the swing circle 7. The swing reduction gear 9 is fixed to the revolving body 3. The swing reduction gear 9 transmits the rotation of the motor 8 to the swing circle 7. Thereby, the revolving body 3 revolves around the center of revolution.

[0014] FIG. 2 is a cross-sectional view of the motor 8 and the swing reduction gear 9. FIG. 3 is an enlarged cross-sectional view of the swing reduction gear 9. As shown in FIGS. 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 projects downward from the motor case 14.

[0015] The swing reduction gear 9 is disposed below the motor 8. The swing reduction gear 9 supports the motor 8. The swing reduction gear 9 includes 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 decelerates 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 disposed 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 so as not to be rotatable relative to the motor shaft 15 and to be movable in the vertical direction. The first sun gear 26 is coupled to the motor shaft 15 by, for example, splines. The first sun gear 26 rotates integrally with the motor shaft 15. The first planetary gear 27 is disposed on the outer periphery of the first sun gear 26. The first planetary gear 27 meshes with the first sun gear 26. The first planetary gear 27 is revolvable around the first sun gear 26. As shown in FIG. 3, the first planetary gear 27 is supported by the first carrier 28 so as to be rotatable via the bearing 29 and the first support shaft 30. The first carrier 28 engages with the first planetary gear 27. The first carrier 28 rotates around the first sun gear 26 together with the revolution 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 disposed 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 decelerates 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 disposed below the first sun gear 26. The second sun gear 31 slidably supports the first sun gear 26 via the 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 so as not to be rotatable relative to the second sun gear 31 and to be movable in the vertical direction. The first carrier 28 is coupled to the second sun gear 31 by, for example, splines. 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] 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 vertically. 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 located 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 in the slewing reduction gear 9 when it 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 lower 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 lower 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 reducer 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 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 reducer 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 reducer 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 reducer 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 the second modified example. Figure 10 is a cross-sectional view of the first carrier 28 according to the second modified example, shown as XX 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 escape from between the first carrier 28 and the second carrier 33 through the holes 54. 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 the 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 sections 55A, 55B, and 55C are not limited to an arc shape, but may also be straight. The number of multiple guide sections 55A, 55B, and 55C is not limited to three, but may be less than three or more than three. [Industrial applicability]

[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. [Explanation of symbols]

[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 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, An oil guide positioned below the first ring gear and protruding radially inward from the inner surface of the case, A slewing reduction gear equipped with a slewing mechanism.

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

3. A second planetary gear mechanism is located below the first planetary gear mechanism and includes a second sun gear that slidably supports the first sun gear, a second planetary gear that meshes with the second sun gear, a second carrier that engages with the second planetary gear, and a second ring gear that meshes with the second planetary gear. Furthermore, The case houses the second planetary gear mechanism. The slewing reduction gear according to claim 1.

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

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

6. The oil guide is positioned facing the space between the first carrier and the second carrier in the radial direction. The slewing reduction gear according to claim 3.

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

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

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

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

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

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

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

14. The oil guide is provided to obstruct the flow of lubricating oil between the first carrier and the second carrier. The slewing speed reducer according to claim 3.

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

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

17. The vehicle and A slewing body supported by the aforementioned traveling body so as to be rotatable, Motor and, A rotation reduction gear connected to the motor, which rotates the rotating body by the rotation of the motor, Equipped with, The aforementioned slewing reduction gear is, 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, An oil guide positioned below the first ring gear and protruding radially inward from the inner surface of the case, including, A type of machinery used for industrial work.

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