Speed reduction device

Abstract

To provide a reduction gear capable of circulating lubricant filled in a housing without increasing foreign matters.SOLUTION: A reduction gear 8 has a first tube 26 and a second tube 27 with both ends opened in a housing 9 and intermediate parts in the length direction annually arranged along an inner peripheral surface 10H of the housing 9 in the housing 9, and a lower rotor 28 and an upper rotor 29 forming a tube pump 25 together with the first tube 26 and the second tube 27. The lower rotor 28 rotates while pressing the first tube 26 between the inner peripheral surface 10H of the housing 9 and itself. The upper rotor 29 rotates while pressing the second tube 27 between the inner peripheral surface 10H of the housing 9 and itself. Thus, lubricant 20 filled in the housing 9 can be circulated via the first tube 26 and the second tube 27.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a speed reduction device used, for example, in a slewing device of a hydraulic excavator or the like.

Background Art

[0002] Generally, the body of a hydraulic excavator, which is representative of construction machinery, is composed of a self-propelled lower traveling body and an upper slewing body rotatably mounted on the lower traveling body. A slewing device for slewing the upper slewing body with respect to the lower traveling body is provided between the lower traveling body and the upper slewing body. The slewing device is provided with a speed reduction device that reduces the rotation of a rotation source such as a hydraulic motor and increases the torque.

[0003] A speed reduction device according to the prior art includes a cylindrical housing filled with lubricating oil therein, a planetary gear speed reduction mechanism provided in the housing for reducing the rotation of a rotation source, and an output shaft for outputting the rotation decelerated by the planetary gear speed reduction mechanism. The housing is filled with lubricating oil, and the lubricating oil lubricates each gear constituting the planetary gear speed reduction mechanism and the bearings that rotatably support the output shaft. Here, when the planetary gear speed reduction mechanism operates, foreign matter (contamination) such as wear powder is generated due to the meshing of a plurality of gears, and this foreign matter mixes into the lubricating oil. As a result, the wear of the gears, bearings, etc. constituting the planetary gear speed reduction mechanism progresses.

[0004] On the other hand, a speed reduction device has been proposed in which lubricating oil is led out of the housing from the lower side of the housing using a plunger pump, and the lubricating oil is circulated so as to return from the upper side of the housing in a state where the mixed foreign matter is removed (Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the speed reducer according to Patent Document 1 has a configuration in which a plunger pump is attached to the lower part of the housing, and the lubricating oil containing foreign matter is sucked up and circulated by this plunger pump. For this reason, when the piston of the plunger pump reciprocates in the cylinder, foreign matter enters the sliding surface between the piston and the cylinder and wears both of them, generating new wear powder. As a result, there is a problem that the amount of foreign matter mixed in the lubricating oil circulating in the housing increases.

[0007] Further, for example, when a sensor for detecting foreign matter contained in the lubricating oil is provided, not only the foreign matter generated in the housing of the speed reducer but also the surplus foreign matter containing the foreign matter generated from the plunger pump is detected by the sensor. For this reason, the amount of foreign matter generated from the speed reducer is not accurately detected by the sensor, and there is a problem that it is difficult to accurately grasp the condition of the speed reducer.

[0008] An object of the present invention is to provide a speed reducer capable of circulating the lubricating oil filled in the housing without increasing foreign matter.

Means for Solving the Problems

[0009] The present invention provides a speed reducer comprising a cylindrical housing filled with lubricating oil therein, a planetary gear speed reduction mechanism provided in the housing for reducing the rotation of a rotation source, and an output shaft for outputting the rotation reduced by the planetary gear speed reduction mechanism. In the speed reducer, a tube having both ends opening into the housing and an intermediate portion annularly arranged along the inner peripheral surface of the housing in the housing, and a rotor housed in the housing and constituting a tube pump together with the tube, the rotor rotating while pressing the tube against the inner peripheral surface of the housing to circulate the lubricating oil filled in the housing through the tube.

Effects of the Invention

[0010] According to the present invention, lubricating oil containing foreign matter such as wear powder generated from the planetary gear reduction mechanism is sucked into the tube pressed by the rotor and circulates in the housing through this tube. Thereby, it is possible to suppress the foreign matter from staying in the housing. Moreover, since the tube pump does not generate foreign matter such as wear powder, it is possible to suppress an increase in foreign matter mixed in the lubricating oil.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the speed reduction device according to the present invention will be described in detail with reference to FIGS. 1 to 5, taking the case where it is applied to a slewing device of a hydraulic excavator as an example.

[0013] In FIG. 1, a slewing ring 3 is provided between a round cylinder 1 provided on a lower traveling body (not shown) of a hydraulic excavator and a slewing frame 2 serving as a base of an upper slewing body (not shown). The slewing ring 3 includes an inner ring 3A fixed to the upper end of the round cylinder 1 using a plurality of bolts 4, an outer ring 3B fixed to the lower surface of the slewing frame 2 using a plurality of bolts 5, and a plurality of rollers 3C, 3D, 3E provided between the inner ring 3A and the outer ring 3B. An internal gear 3F is formed over the entire circumference on the inner peripheral side of the inner ring 3A. The slewing frame 2 is supported rotatably on the round cylinder 1 of the lower traveling body via the slewing ring 3.

[0014] A slewing device 6 is provided on the slewing frame 2. The slewing device 6 is composed of a slewing motor 7 as a rotation source that rotationally drives a motor shaft 7A when pressure oil is supplied from the outside, and a speed reduction device 8 described later that reduces the rotation of the slewing motor 7 (motor shaft 7A) and transmits it to the slewing ring 3. Note that as the slewing motor 7, an electric motor may be used instead of a hydraulic motor.

[0015] The speed reduction device 8 constitutes the slewing device 6 together with the slewing motor 7. The speed reduction device 8 reduces the rotation of the slewing motor 7 (motor shaft 7A) and drives an output shaft 14 described later. The speed reduction device 8 includes a housing 9, planetary gear speed reduction mechanisms 12, 13, and an output shaft 14, and transmits the rotation of the slewing motor 7 (motor shaft 7A) to the output shaft 14 in a state of being reduced in speed in two stages by the planetary gear speed reduction mechanisms 12, 13.

[0016] The housing 9 constitutes the outer shell of the speed reduction device 8. The housing 9 is formed in a stepped cylindrical shape extending in the vertical direction. The housing 9 has a shaft support portion 10 disposed on the lower side and a speed reduction mechanism housing portion 11 disposed on the upper side. The lower side of the shaft support portion 10 is attached to the slewing frame 2, and the slewing motor 7 is attached to the upper side of the speed reduction mechanism housing portion 11.

[0017] The shaft support portion 10 forms the lower part of the housing 9 and supports the output shaft 14. A disk-shaped lower flange 10A that expands in diameter outward in the radial direction is formed on the lower end side of the shaft support portion 10, and the lower flange 10A is attached to the swivel frame 2 using a plurality (only one is shown in the figure) of bolts 10B. A disk-shaped upper flange 10C that expands in diameter outward in the radial direction is formed on the upper end side of the shaft support portion 10, and a speed reduction mechanism housing portion 11 is attached to the upper flange 10C.

[0018] On the inner peripheral side of the shaft support portion 10, a cylindrical lower support portion 10D that protrudes downward from the lower flange 10A and projects inward in the radial direction, and an annular upper support portion 10E that is located on the lower side of the upper flange 10C and projects inward in the radial direction are formed. Here, as shown in FIG. 3, on the inner peripheral side of the shaft support portion 10 located between the upper flange 10C and the upper support portion 10E, a tube guide portion 10F and a tube connection portion 10G are provided. The tube guide portion 10F has an arcuate inner peripheral surface centered on the axis A-A of the output shaft 14. The tube connection portion 10G forms a rectangular frame shape and is continuous with the tube guide portion 10F, projecting outward in the radial direction from the tube guide portion 10F. On the inner peripheral surface 10H of the tube guide portion 10F, a lower guide groove 23 and an upper guide groove 24 described later are provided, and a first tube 26 and a second tube 27 described later are connected to the tube connection portion 10G.

[0019] The speed reduction mechanism housing portion 11 is provided above the shaft support portion 10. The speed reduction mechanism housing portion 11 forms the upper part of the housing 9 and houses planetary gear speed reduction mechanisms 12, 13, etc. The speed reduction mechanism housing portion 11 includes a lower cylindrical portion 11A and an upper cylindrical portion 11B that overlap in the vertical direction, and a lid portion 11C that closes the upper end side of the upper cylindrical portion 11B. These lower cylindrical portion 11A, upper cylindrical portion 11B, and lid portion 11C are attached to the upper flange 10C of the shaft support portion 10 using a plurality of bolts 11D.

[0020] On the inner peripheral side of the lower cylindrical portion 11A, an internal gear 11E is formed over the entire circumference, and a planetary gear 13B described later meshes with the internal gear 11E. On the inner peripheral side of the upper cylindrical portion 11B, an internal gear 11F is formed over the entire circumference, and a planetary gear 12B described later meshes with the internal gear 11F. A turning motor 7 is attached to the upper surface side of the lid portion 11C, and the motor shaft 7A of the turning motor 7 projects into the speed reduction mechanism housing portion 11.

[0021] The first-stage planetary gear speed reduction mechanism 12 is provided in the speed reduction mechanism housing portion 11 of the housing 9. The planetary gear speed reduction mechanism 12 includes a sun gear 12A spline-coupled to the motor shaft 7A of the turning motor 7, a plurality of planetary gears 12B (only one is shown in the figure), and a carrier 12C. The planetary gear 12B meshes with the sun gear 12A and the upper internal gear 11F of the speed reduction mechanism housing portion 11, and revolves around the sun gear 12A while rotating on its own axis. The carrier 12C rotatably supports a plurality of planetary gears 12B via pins 12D and is spline-coupled to the second-stage sun gear 13A.

[0022] The second-stage planetary gear speed reduction mechanism 13 is located below the planetary gear speed reduction mechanism 12 and is provided in the speed reduction mechanism housing portion 11 of the housing 9. The planetary gear speed reduction mechanism 13 includes a sun gear 13A spline-coupled to the carrier 12C of the first stage, a plurality of planetary gears 13B (only one is shown in the figure), and a carrier 13C. The planetary gear 13B meshes with the sun gear 13A and the lower internal gear 11E of the speed reduction mechanism housing portion 11, and revolves around the sun gear 13A while rotating on its own axis.

[0023] The carrier 13C rotatably supports a plurality of planetary gears 13B via pins 13D, and a cylindrical portion 13E protruding toward the shaft support portion 10 is provided on the lower surface side thereof. An internal spline (female spline) 13F is formed on the inner peripheral side of the cylindrical portion 13E, and this internal spline 13F is spline-coupled to the external spline 14A of the output shaft 14. As a result, the rotation of the turning motor 7 (motor shaft 7A) is decelerated in two stages by the planetary gear speed reduction mechanisms 12 and 13, and a large rotational torque is transmitted to the output shaft 14.

[0024] Here, on the lower surface side of the second-stage carrier 13C, a plurality (for example, three) of columnar rotor support pins 13G are provided so as to protrude toward the shaft support portion 10 side. These plurality of rotor support pins 13G are arranged at equal angular intervals around the axis A-A of the output shaft 14 so as to surround the cylindrical portion 13E. These plurality of rotor support pins 13G rotatably support the lower rotor 28 and the upper rotor 29 described later, respectively.

[0025] The output shaft 14 is provided to extend in the axial direction (vertical direction) within the housing 9 and outputs the rotation decelerated by the planetary gear reduction mechanisms 12 and 13. A male spline (shaft spline) 14A is formed at one end (upper end) in the axial direction of the output shaft 14, and the male spline 14A is spline-coupled to a female spline 13F formed on the second-stage carrier 13C. A pinion 15 is fixed to the other end (lower end) in the axial direction of the output shaft 14, and the pinion 15 meshes with an internal gear 3F provided on the inner ring 3A of the swivel ring 3.

[0026] The portion of the output shaft 14 adjacent to the upper side of the pinion 15 becomes a lower bearing mounting portion 14B, and the lower bearing mounting portion 14B corresponds to a lower support portion 10D provided on the shaft support portion 10 of the housing 9. The portion of the output shaft 14 adjacent to the lower side of the male spline 14A becomes an upper bearing mounting portion 14C, and the upper bearing mounting portion 14C corresponds to an upper support portion 10E provided on the shaft support portion 10 of the housing 9.

[0027] The lower bearing 16 is provided between the shaft support portion 10 of the housing 9 and the lower bearing mounting portion 14B of the output shaft 14. The inner ring of the lower bearing 16 is fitted to the outer peripheral surface of the lower bearing mounting portion 14B, and the outer ring of the lower bearing 16 is fitted to the inner peripheral surface of the lower support portion 10D provided on the shaft support portion 10. The upper bearing 17 is provided between the shaft support portion 10 of the housing 9 and the upper bearing mounting portion 14C of the output shaft 14. The inner ring of the upper bearing 17 is fitted to the outer peripheral surface of the upper bearing mounting portion 14C, and the outer ring of the upper bearing 17 is fitted to the inner peripheral surface of the upper support portion 10E provided on the shaft support portion 10. These lower bearing 16 and upper bearing 17 rotatably support the output shaft 14 with respect to the housing 9.

[0028] At the lower end of the lower support portion 10D provided in the shaft support portion 10 of the housing 9, an annular retainer 18 is attached using a plurality of (only one shown in the figure) bolts 18A. The retainer 18 holds the lower bearing 16 between it and the lower support portion 10D. Also, an annular oil seal 19 is provided over the entire circumference between the inner peripheral surface of the retainer 18 and the outer peripheral surface of the output shaft 14. The oil seal 19 seals the gap between the output shaft 14 and the retainer 18 in a liquid-tight manner and holds the lubricating oil 20 filled in the housing 9. The lubricating oil 20 filled in the housing 9 lubricates the sun gear 12A of the planetary gear reduction mechanism 12, the planetary gears 12B, the sun gear 13A of the planetary gear reduction mechanism 13, the planetary gears 13B, the lower bearing 16, the upper bearing 17, and the like.

[0029] On the inner peripheral surface 10H of the tube guide portion 10F provided above the upper support portion 10E in the shaft support portion 10 of the housing 9, a lower annular protrusion 21 and an upper annular protrusion 22 that project annularly radially inward from this inner peripheral surface 10H are integrally formed with a certain interval in the vertical direction. An annular lower guide groove 23 along the inner peripheral surface 10H of the tube guide portion 10F is provided between the upper support portion 10E and the lower annular protrusion 21. An annular upper guide groove 24 along the inner peripheral surface 10H of the tube guide portion 10F is provided between the lower annular protrusion 21 and the upper annular protrusion 22.

[0030] The vertical width dimension (groove width) of the lower guide groove 23 and the vertical width dimension (groove width) of the upper guide groove 24 are set to be equal. The lower guide groove 23 aligns the intermediate tube 26B of the first tube 26 along the inner peripheral surface 10H of the tube guide portion 10F and guides the lower rotor 28 so as to overlap the intermediate tube 26B. The upper guide groove 24 aligns the intermediate tube 27B of the second tube 27 along the inner peripheral surface 10H of the tube guide portion 10F and guides the upper rotor 29 so as to overlap the intermediate tube 27B.

[0031] As shown in Fig. 4, a plurality (for example, three) of rotor insertion portions 21A are provided on the inner peripheral edge of the lower annular protrusion 21. These plurality of rotor insertion portions 21A are formed by recessing the inner peripheral edge of the lower annular protrusion 21 toward the inner peripheral surface 10H side of the tube guide portion 10F, and are arranged at equal angular intervals around the axis A-A of the output shaft 14. When the planetary gear reduction mechanism 13 is incorporated into the housing 9, the lower rotor 28 moved to the position indicated by the two-dot chain line in Fig. 4 is inserted into the rotor insertion portion 21A. Also, a plurality of rotor insertion portions (not shown) are provided on the inner peripheral edge of the upper annular protrusion 22 in the same manner as the lower annular protrusion 21. When the planetary gear reduction mechanism 13 is incorporated into the housing 9, the upper rotor 29 is inserted into the rotor insertion portion of the upper annular protrusion 22.

[0032] Next, the tube pump 25 used in the speed reduction device 8 of the present embodiment will be described.

[0033] The tube pump 25 is provided above the upper support portion 10E among the shaft support portions 10 constituting the housing 9 of the speed reduction device 8. The tube pump 25 includes a first tube 26, a second tube 27, a lower rotor 28, and an upper rotor 29, and circulates the lubricating oil 20 filled in the housing 9.

[0034] The first tube 26 is configured by connecting a plurality (for example, three) of tubes in series, and both ends (26D, 31B) in the length direction are open in the housing 9. Specifically, the first tube 26 is composed of a suction-side tube 26A that constitutes one side in the length direction and is arranged outside the housing 9, an intermediate tube 26B that constitutes the intermediate portion in the length direction and is arranged inside the housing 9, and a discharge-side tube 26C that constitutes the other side in the length direction and is arranged outside the housing 9. One end of the first tube 26 is constituted by one end 26D of the suction-side tube 26A described later, and the other end of the first tube 26 is constituted by the other end 31B of the common discharge pipe 31 described later.

[0035] The suction-side tube 26A is disposed outside the housing 9. One end 26D of the suction-side tube 26A is attached with a one-side connector 26A1. The one-side connector 26A1 is connected to the shaft support portion 10 between the lower support portion 10D and the upper support portion 10E and opens into the housing 9 (see FIG. 2). That is, one end 26D of the suction-side tube 26A opens into the housing 9 via the one-side connector 26A1. The other end of the suction-side tube 26A is attached with an other-side connector 26A2. The other-side connector 26A2 is connected to the tube connection portion 10G of the shaft support portion 10 (see FIGS. 3 and 5).

[0036] The intermediate tube 26B constitutes the intermediate portion of the first tube 26 and is provided in the shaft support portion 10 of the housing 9. The intermediate tube 26B engages with the lower guide groove 23 provided on the inner peripheral surface 10H of the tube guide portion 10F of the shaft support portion 10 and is annularly arranged along the inner peripheral surface 10H of the tube guide portion 10F. One end of the intermediate tube 26B is attached with a one-side connector 26B1. The one-side connector 26B1 is concentrically connected to the tube connection portion 10G of the shaft support portion 10 with the other-side connector 26A2 of the suction-side tube 26A and communicates with the other-side connector 26A2 of the suction-side tube 26A via the tube connection portion 10G (see FIG. 3). The other end of the intermediate tube 26B is attached with an other-side connector 26B2. The other-side connector 26B2 is connected to the tube connection portion 10G of the shaft support portion 10 adjacent to the one-side connector 26B1.

[0037] The discharge-side tube 26C is disposed outside the housing 9. One end of the discharge-side tube 26C is attached with a one-side connector 26C1. The one-side connector 26C1 is concentrically connected to the tube connection portion 10G of the shaft support portion 10 with the other-side connector 26B2 of the intermediate tube 26B and communicates with the other-side connector 26B2 of the intermediate tube 26B via the tube connection portion 10G (see FIG. 3). The other end of the discharge-side tube 26C is connected to a filter unit 30 described later.

[0038] Similar to the first tube 26, the second tube 27 is formed by connecting a plurality (for example, three) of tubes in series, and both ends (27D, 31B) in the longitudinal direction are open inside the housing 9. As shown in FIG. 5, the second tube 27 includes a suction-side tube 27A that forms one side in the longitudinal direction and is disposed outside the housing 9, an intermediate tube 27B that forms the middle part in the longitudinal direction and is disposed inside the housing 9, and a discharge-side tube 27C that forms the other side in the longitudinal direction and is disposed outside the housing 9. One end of the second tube 27 is formed by one end 27D of the suction-side tube 27A described later, and the other end of the second tube 27 is formed by the other end 31B of the common discharge pipe 31 described later.

[0039] One end 27D of the suction-side tube 27A is connected to the shaft support portion 10 between the lower support portion 10D and the upper support portion 10E in the same manner as the suction-side tube 26A of the first tube 26 and is open inside the housing 9. An other-side connector 27A1 is attached to the other end of the suction-side tube 27A. The other-side connector 27A1 is connected to the tube connection portion 10G of the shaft support portion 10 in the same manner as the suction-side tube 26A of the first tube 26.

[0040] The intermediate tube 27B forms the middle part of the second tube 27 and is provided inside the shaft support portion 10 of the housing 9, spaced above the intermediate tube 26B of the first tube 26. The intermediate tube 27B engages in an upper guide groove 24 provided on the inner peripheral surface 10H of the tube guide portion 10F of the shaft support portion 10 and is arranged annularly along the inner peripheral surface 10H of the tube guide portion 10F. One end of the intermediate tube 27B is connected to the tube connection portion 10G of the shaft support portion 10 via a one-side connector 27B1 and communicates with the other-side connector 27A1 of the suction-side tube 27A via the tube connection portion 10G. The other end of the intermediate tube 27B is connected to the tube connection portion 10G of the shaft support portion 10 via an other-side connector 27B2 (see FIG. 5).

[0041] The discharge-side tube 27C is disposed outside the housing 9. One end of the discharge-side tube 27C is connected to the tube connection portion 10G of the shaft support portion 10 via a one-side connector 27C1, and communicates with the other-side connector 27B2 of the intermediate tube 27B via the tube connection portion 10G. The other end of the discharge-side tube 27C is connected to the filter unit 30.

[0042] The plurality of lower rotors 28 and upper rotors 29 are housed in the housing 9, and together with the first tube 26 and the second tube 27, constitute a tube pump 25. These plurality (for example, three) of lower rotors 28 and upper rotors 29 are each rotatably supported by rotor support pins 13G provided on a carrier 13C that constitutes a second-stage planetary gear reduction mechanism 13. With the planetary gear reduction mechanism 13 assembled in the reduction mechanism housing portion 11 of the housing 9, the lower rotor 28 engages with a lower guide groove 23 provided on the inner peripheral surface 10H of the tube guide portion 10F, and the upper rotor 29 engages with an upper guide groove 24 provided on the inner peripheral surface 10H of the tube guide portion 10F.

[0043] Therefore, when the turning device 6 operates, the second-stage carrier 13C rotates about the axis A-A of the output shaft 14, so that the lower rotor 28 and the upper rotor 29 rotate within the housing 9 together with the carrier 13C. At this time, the lower rotor 28 rotates along the lower guide groove 23 while pressing the intermediate tube 26B of the first tube 26 against the inner peripheral surface 10H of the tube guide portion 10F, and the upper rotor 29 rotates along the upper guide groove 24 while pressing the intermediate tube 27B of the second tube 27 against the inner peripheral surface 10H of the tube guide portion 10F.

[0044] The filter unit 30 is connected to the discharge-side tube 26C of the first tube 26 and the discharge-side tube 27C of the second tube 27. As shown in FIG. 5, the filter unit 30 includes a common discharge pipeline 31, a first check valve 32 and a second check valve 33, a contamination sensor 34, and an oil filter 35. The filter unit 30 is attached to the housing 9 using, for example, bolts or the like (not shown).

[0045] The common discharge pipeline 31 forms a part of the first tube 26 and the second tube 27, and connects between the discharge-side tube 26C of the first tube 26, the discharge-side tube 27C of the second tube 27, and the housing 9. That is, one end of the common discharge pipeline 31 is connected to the other ends of the discharge-side tubes 26C and 27C, and the other end 31B of the common discharge pipeline 31 forms the other ends of the first tube 26 and the second tube 27. The other end 31B of the common discharge pipeline 31 is attached to the lid portion 11C of the housing 9 (the speed reduction mechanism housing portion 11) via a connector 31A and opens into the housing 9. Therefore, the other ends of the first tube 26 and the second tube 27 open into the housing 9 via the common discharge pipeline 31.

[0046] The first check valve 32 is disposed in the middle of the discharge-side tube 26C, allows the flow of the lubricating oil 20 from the discharge-side tube 26C toward the common discharge pipeline 31, and prohibits the reverse flow. The second check valve 33 is disposed in the middle of the discharge-side tube 27C, allows the flow of the lubricating oil 20 from the discharge-side tube 27C toward the common discharge pipeline 31, and prohibits the reverse flow.

[0047] The contamination sensor 34 as a dirt detector is provided in the middle of the common discharge pipeline 31. The contamination sensor 34 monitors the condition of the reduction gear 8 by, for example, measuring the amount of foreign matter contained in the lubricating oil 20 flowing through the common discharge pipeline 31 to detect the dirt of the lubricating oil 20. The oil filter 35 is located between the contamination sensor 34 and the housing 9 and is provided in the middle of the common discharge pipeline 31. The oil filter 35 purifies the lubricating oil 20 flowing back into the housing 9 by capturing foreign matter contained in the lubricating oil 20.

[0048] Here, when the output shaft 14 rotates in the direction of arrow B (positive direction) in FIG. 3, the lower rotor 28 rotates while pressing the intermediate tube 26B of the first tube 26, thereby exerting a pumping action. As a result, the lubricating oil 20 filled in the housing 9 is sucked into the suction side tube 26A of the first tube 26 as shown by the broken line arrow in FIG. 5 and sent to the discharge side tube 26C through the intermediate tube 26B. The lubricating oil 20 sent to the discharge side tube 26C passes through the first check valve 32 of the filter unit 30, the contamination sensor 34, and the oil filter 35, and then is discharged into the housing 9 from the other end of the common discharge pipeline 31.

[0049] On the other hand, when the output shaft 14 rotates in the direction opposite to the direction of arrow B in FIG. 3 (reverse direction), the upper rotor 29 rotates while pressing the intermediate tube 27B of the second tube 27, thereby exerting a pumping action. As a result, the lubricating oil 20 filled in the housing 9 is sucked into the suction side tube 27A of the second tube 27 as shown by the solid line arrow in FIG. 5 and sent to the discharge side tube 27C through the intermediate tube 27B. The lubricating oil 20 sent to the discharge side tube 27C passes through the second check valve 33 of the filter unit 30, the contamination sensor 34, and the oil filter 35, and then is discharged into the housing 9 from the other end of the common discharge pipeline 31.

[0050] As described above, when the output shaft 14 rotates in the forward direction, the tube pump 25 circulates the lubricating oil 20 in the housing 9 through the first tube 26 due to the pumping action of the lower rotor 28. When the output shaft 14 rotates in the reverse direction, the tube pump 25 circulates the lubricating oil 20 in the housing 9 through the second tube 27 due to the pumping action of the upper rotor 29. As a result, foreign matters such as wear powder mixed in the lubricating oil 20 are prevented from settling in the housing 9 and staying in the lower support portion 10D, and the lower bearing 16 and the like can be protected from foreign matters. In this case, compared with the plunger pump described in the prior art, the tube pump 25 does not generate foreign matters such as wear powder by itself, so that an increase in foreign matters mixed in the lubricating oil 20 can be suppressed.

[0051] The speed reducer 8 according to the present embodiment has the configuration as described above. When the slewing device 6 equipped with the speed reducer 8 operates, the motor shaft 7A of the slewing motor 7 rotates. The rotation of the motor shaft 7A is reduced in two stages by the planetary gear reduction mechanisms 12 and 13 and transmitted to the output shaft 14, and the output shaft 14 rotates with a large torque. As a result, the pinion 15 attached to the output shaft 14 revolves along the internal gear 3F while meshing with the internal gear 3F provided on the inner ring 3A of the slewing ring 3. Due to the revolving force of the pinion 15, the slewing frame 2 revolves with respect to the cylindrical body 1, and the upper slewing body can be slewed on the lower traveling body.

[0052] Here, when the slewing device 6 operates, the lubricating oil 20 filled in the housing 9 lubricates the sun gears 12A and 13A, the planetary gears 12B and 13B, which constitute the planetary gear reduction mechanisms 12 and 13, the lower bearing 16 that supports the output shaft 14, and the upper bearing 17. However, when the planetary gear reduction mechanisms 12 and 13 operate, foreign matters such as wear powder are generated due to the meshing of the sun gears 12A and 13A, the planetary gears 12B and 13B, etc., and this foreign matter is mixed into the lubricating oil 20. For this reason, the foreign matter settles in the housing 9 by its own weight and stays in the lower support portion 10D of the shaft support portion 10 where the lower bearing 16 is attached, etc., and a part of this foreign matter may penetrate between the inner ring and the outer ring of the lower bearing 16 and cause the lower bearing 16 to wear prematurely.

[0053] In contrast, the speed reducer 8 according to the present embodiment is configured to circulate the lubricating oil 20 using the tube pump 25 in order to prevent foreign matter mixed in the lubricating oil 20 from staying in the lower support portion 10D of the shaft support portion 10 or the like. Therefore, the operation of the tube pump 25 during the operation of the speed reducer 8 will be described.

[0054] When the rotation of the swing motor 7 is transmitted to the output shaft 14 via the speed reducer 8 and the output shaft 14 rotates, the lower rotor 28 and the upper rotor 29 attached to the rotor support pins 13G of the second-stage carrier 13C rotate together with the carrier 13C. As a result, the lower rotor 28 rotates along the lower guide groove 23 while pressing the intermediate tube 26B of the first tube 26 against the inner peripheral surface 10H of the tube guide portion 10F. The upper rotor 29 rotates along the upper guide groove 24 while pressing the intermediate tube 27B of the second tube 27 against the inner peripheral surface 10H of the tube guide portion 10F.

[0055] In this case, the intermediate tube 26B of the first tube 26 is aligned along the inner peripheral surface 10H of the tube guide portion 10F by the lower guide groove 23, and the orbit of the lower rotor 28 is guided by the lower guide groove 23, so that the intermediate tube 26B can be reliably pressed by the lower rotor 28. Similarly, the intermediate tube 27B of the second tube 27 is aligned along the inner peripheral surface 10H of the tube guide portion 10F by the upper guide groove 24, and the orbit of the upper rotor 29 is guided by the upper guide groove 24, so that the intermediate tube 27B can be reliably pressed by the upper rotor 29.

[0056] Here, when the output shaft 14 rotates in the positive direction (the direction of arrow B in FIG. 3), the lower rotor 28 rotates while pressing the intermediate tube 26B of the first tube 26, thereby exerting a pumping action. That is, the lubricating oil 20 filled in the housing 9 is sucked into the suction side tube 26A of the first tube 26 as shown by the dashed arrow in FIG. 5, and is sent out to the discharge side tube 26C through the intermediate tube 26B. The lubricating oil 20 sent out to the discharge side tube 26C passes through the first check valve 32, the contamination sensor 34, and the oil filter 35 of the filter unit 30, and then is discharged into the housing 9 from the other end of the common discharge pipe 31. Note that the upper rotor 29 also rotates while pressing the intermediate tube 27B of the second tube 27, but a second check valve 33 is provided in the discharge side tube 27C of the second tube 27. Therefore, when the output shaft 14 rotates in the positive direction, the lubricating oil 20 is not sucked into the suction side tube 27A of the second tube 27.

[0057] On the other hand, when the output shaft 14 rotates in the reverse direction (the direction opposite to the direction of arrow B in FIG. 3), the upper rotor 29 rotates while pressing the intermediate tube 27B of the second tube 27, thereby exerting a pumping action. That is, the lubricating oil 20 filled in the housing 9 is sucked into the suction side tube 27A of the second tube 27 as shown by the solid arrow in FIG. 5, and is sent out to the discharge side tube 27C through the intermediate tube 27B. The lubricating oil 20 sent out to the discharge side tube 27C passes through the second check valve 33, the contamination sensor 34, and the oil filter 35 of the filter unit 30, and then is discharged into the housing 9 from the other end of the common discharge pipe 31. Note that the lower rotor 28 also rotates while pressing the intermediate tube 26B of the first tube 26, but a first check valve 32 is provided in the discharge side tube 26C of the first tube 26. Therefore, when the output shaft 14 rotates in the reverse direction, the lubricating oil 20 is not sucked into the suction side tube 26A of the first tube 26.

[0058] Thus, when the output shaft 14 rotates in the forward direction, the lubricating oil 20 in the housing 9 is sucked into the first tube 26 near the lower support portion 10D and returned into the housing 9 from the lid portion 11C of the speed reduction mechanism housing portion 11. On the other hand, when the output shaft 14 rotates in the reverse direction, the lubricating oil 20 in the housing 9 is sucked into the second tube 27 near the lower support portion 10D and returned into the housing 9 from the lid portion 11C of the speed reduction mechanism housing portion 11. Therefore, regardless of the rotation direction of the output shaft 14 (the turning direction of the upper swing body by the swing device 6), the lubricating oil 20 can always circulate in the housing 9 via the first tube 26 or the second tube 27.

[0059] Therefore, it is possible to prevent foreign matter mixed in the lubricating oil 20 from staying in the lower support portion 10D of the shaft support portion 10 where the lower bearing 16 is attached, etc., and suppress wear of the lower bearing 16, etc. due to foreign matter. Moreover, unlike the plunger pump described in the prior art, the tube pump 25 does not generate foreign matter such as wear powder by itself. As a result, while suppressing an increase in foreign matter mixed in the lubricating oil 20, the lubricating oil 20 can be circulated in the housing 9.

[0060] Also, an oil filter 35 is provided in the common discharge pipeline 31 to which the discharge side tube 26C of the first tube 26 and the discharge side tube 27C of the second tube 27 are connected. For this reason, when the lubricating oil 20 circulates in the housing 9 via the first tube 26 or the second tube 27, foreign matter mixed in this lubricating oil 20 can be captured by the oil filter 35. As a result, the amount of foreign matter contained in the lubricating oil 20 can be reduced, and the planetary gear speed reduction mechanisms 12, 13, the lower bearing 16, the upper bearing 17, etc. can be lubricated with the purified lubricating oil 20.

[0061] Furthermore, a contamination sensor 34 is provided in the common discharge pipe 31. Thereby, the contamination of the lubricating oil 20 circulating in the housing 9 via the first tube 26 or the second tube 27 can be detected by the contamination sensor 34. In this case, since the tube pump 25 does not generate foreign matters such as wear powder by itself, surplus foreign matters other than the wear powder generated from the planetary gear reduction mechanisms 12, 13, etc. disposed in the housing 9 are not detected. As a result, since only the amount of foreign matters generated from the reduction device 8 can be accurately detected by the contamination sensor 34, the condition of the reduction device 8 can be accurately grasped.

[0062] Thus, the reduction device 8 according to the present embodiment includes a cylindrical housing 9 filled with lubricating oil 20 inside, planetary gear reduction mechanisms 12, 13 provided in the housing 9 to reduce the rotation of the swing motor 7, and an output shaft 14 that outputs the rotation reduced by the planetary gear reduction mechanisms 12, 13. And the reduction device 8 has a first tube 26 and a second tube 27 having both ends (26D, 27D, 31B) opening into the housing 9 and intermediate portions (intermediate tubes 26B, 27B) annularly arranged along the inner peripheral surface 10H of the housing 9 inside the housing 9, and is housed in the housing 9 and constitutes a tube pump 25 together with the first tube 26 and the second tube 27, and rotates while pressing the first tube 26 and the second tube 27 against the inner peripheral surface 10H of the housing 9, thereby circulating the lubricating oil 20 filled in the housing 9 via the first tube 26 and the second tube 27, and a lower rotor 28 and an upper rotor 29.

[0063] According to this configuration, the lubricating oil 20 containing foreign matters such as wear powder generated from the planetary gear reduction mechanisms 12 and 13 is sucked into the first tube 26 pressed by the lower rotor 28 and the second tube 27 pressed by the upper rotor 29, and circulates in the housing 9 through these first tube 26 and second tube 27. Thereby, it is possible to suppress the foreign matters from staying in the housing 9. Moreover, since the tube pump 25 does not generate foreign matters such as wear powder, it is possible to suppress an increase in foreign matters mixed in the lubricating oil 20.

[0064] In the embodiment, on the inner peripheral surface 10H of the housing 9, an intermediate portion in the longitudinal direction of the first tube 26 and the second tube 27 is aligned along the inner peripheral surface 10H of the housing 9, and lower guide grooves 23 and upper guide grooves 24 for guiding the lower rotor 28 and the upper rotor 29 so as to overlap the first tube 26 and the second tube 27 are provided. According to this configuration, the orbits of the lower rotor 28 and the upper rotor 29 can be regulated by the lower guide grooves 23 and the upper guide grooves 24. Therefore, the intermediate portion in the longitudinal direction of the first tube 26 and the second tube 27 aligned along the inner peripheral surface 10H of the housing 9 can be reliably pressed by the lower rotor 28 and the upper rotor 29.

[0065] In the embodiment, the tube is composed of a first tube 26 that sucks the lubricating oil 20 in the housing 9 from one end side and discharges the lubricating oil 20 into the housing 9 from the other end side when being pressed by the lower rotor 28 when the output shaft 14 rotates in the positive direction, and a second tube 27 that sucks the lubricating oil 20 in the housing 9 from one end side and discharges the lubricating oil 20 into the housing 9 from the other end side when being pressed by the upper rotor 29 when the output shaft 14 rotates in the direction opposite to the positive direction. According to this configuration, the lubricating oil 20 can be circulated in the housing 9 through the first tube 26 or the second tube 27 regardless of whether the output shaft 14 rotates in the positive direction or the reverse direction.

[0066] In the embodiment, the planetary gear reduction mechanism 13 includes a sun gear 13A, an inner lower gear 11E provided on the inner peripheral side of the housing 9 and meshing with the sun gear 13A, and a plurality of planetary gears 13B that revolve around the sun gear 13A while rotating on their own axes. The planetary gear reduction mechanism 13 further includes a carrier 13C that rotatably supports the plurality of planetary gears 13B and rotates together with the output shaft 14. The lower rotor 28 and the upper rotor 29 are provided on the carrier 13C. According to this configuration, when the planetary gear reduction mechanism 13 operates and the carrier 13C rotates, the rotation of the carrier 13C can be utilized to rotate the lower rotor 28 and the upper rotor 29, thereby pressing the first tube 26 and the second tube 27.

[0067] In the embodiment, the speed reduction device 8 is provided with an oil filter 35 that captures foreign matter mixed in the lubricating oil 20 flowing through the first tube 26 and the second tube 27. According to this configuration, when the lubricating oil 20 circulates in the housing 9 via the first tube 26 or the second tube 27, the foreign matter mixed in the lubricating oil 20 can be captured by the oil filter 35, thereby purifying the lubricating oil 20.

[0068] In the embodiment, the speed reduction device 8 is provided with a contamination sensor 34 that detects the contamination of the lubricating oil 20 flowing through the first tube 26 and the second tube 27. According to this configuration, the contamination of the lubricating oil 20 circulating in the housing 9, that is, the amount of foreign matter such as wear powder mixed in the lubricating oil 20, can be detected by the contamination sensor 34, and the condition of the speed reduction device 8 can be grasped.

[0069] In the embodiment, the case where the tube pump 25 is disposed above the upper support portion 10E of the shaft support portion 10 constituting the housing 9 is illustrated. However, the present invention is not limited to this. For example, the tube pump may be disposed between the lower support portion 10D and the upper support portion 10E of the shaft support portion 10.

[0070] In addition, in the embodiment, the case where the lower rotor 28 and the upper rotor 29 are attached to the carrier 13C of the second-stage planetary gear reduction mechanism 13 is illustrated. However, the present invention is not limited to this, and for example, the lower rotor and the upper rotor may be attached to the output shaft 14 via a bracket or the like.

[0071] Furthermore, in the embodiment, by connecting the other end of the discharge-side tube 26C constituting the first tube 26 and the other end of the discharge-side tube 27C constituting the second tube 27 to the common discharge pipe 31, the case where the other ends of the first tube 26 and the second tube 27 that open into the housing 9 are constituted by the other end 31B of the common discharge pipe 31 is illustrated. However, the present invention is not limited to this, and for example, filter units may be provided in the middle of the discharge-side tube 26C and the discharge-side tube 27C, respectively, and the other ends of the discharge-side tube 26C and the discharge-side tube 27C may be individually opened into the housing 9.

Explanation of Signs

[0072] 8 Reduction device 9 Housing 10H Inner peripheral surface 12, 13 Planetary gear reduction mechanism 13A Sun gear 13B Planetary gear 13C Carrier 14 Output shaft 20 Lubricating oil 23 Lower guide groove 24 Upper guide groove 25 Tube pump 26 First tube (tube) 26B, 27B Intermediate tube 27 Second tube (tube) 28 Lower rotor 29 Upper rotor 31 Common discharge pipe (tube) 34 Contamination sensor (dirt detector) 35 Oil filter (filter)

Claims

1. A speed reduction device comprising a cylindrical housing filled with lubricating oil therein, a planetary gear speed reduction mechanism provided in the housing for reducing the rotation of a rotation source, and an output shaft for outputting the rotation decelerated by the planetary gear speed reduction mechanism, a tube having both ends opening into the housing and an intermediate portion annularly disposed along the inner peripheral surface of the housing within the housing, and a rotor accommodated in the housing and constituting a tube pump together with the tube, the rotor rotating while pressing the tube against the inner peripheral surface of the housing to circulate the lubricating oil filled in the housing through the tube. The speed reduction device is characterized by this.

2. The speed reduction device according to claim 1, wherein a guide groove is provided on the inner peripheral surface of the housing to align the intermediate portion of the tube along the inner peripheral surface of the housing and guide the rotor so as to overlap the tube.

3. The tube includes a first tube that sucks lubricating oil in the housing from one end side and discharges the lubricating oil into the housing from the other end side when being pressed by the rotor when the output shaft rotates in the forward direction, and a second tube that sucks lubricating oil in the housing from one end side and discharges the lubricating oil into the housing from the other end side when being pressed by the rotor when the output shaft rotates in a direction opposite to the forward direction. The speed reduction device according to claim 1 is characterized by being composed of these.

4. The planetary gear speed reduction mechanism includes a sun gear, an internal gear provided on the inner peripheral side of the housing, a plurality of planetary gears meshing with the sun gear and revolving while rotating around the sun gear, and a carrier rotatably supporting the plurality of planetary gears and rotating together with the output shaft, and the rotor is provided on the carrier. The speed reduction device according to claim 1 is characterized by this.

5. The speed reducer according to claim 1, further comprising a filter for capturing foreign matter mixed in the lubricating oil flowing in the tube.

6. The speed reducer according to claim 1, further comprising a dirt detector for detecting dirt of the lubricating oil flowing in the tube.

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