Speed reducer, actuator, and construction machine

Abstract

To provide a speed reducer capable of being rotated at a high speed and miniaturized by suppressing heat generation of a speed reduction portion and having excellent mountability to a construction machine and the like.SOLUTION: A speed reducer includes: a speed reduction portion 4 reducing rotation driving force of an electric motor 2 and transmitting the same to a rotation driving portion; a cylindrical case 5 housing a motor shaft 20 of the electric motor 2 and the speed reduction portion 4 and directed in a rotation axial direction of the electric motor 2 at its cylindrical shaft; an axial flow channel 63 disposed in the case 5 along the rotation axial direction so that cooling water flows; two plates (motor flange 23, second carrier 46) closing both ends in the rotation axial direction, of the case 5; and an input-side connection flow channel 65 and an output-side connection flow channel 64 disposed on at least one of two plates and connected to an axial flow channel 63 to allow the cooing water to flow therein.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a reducer, an actuator, and a construction machine. [Background technology]

[0002] In construction machinery such as excavators, an engine is used as a drive source to hydraulically control each actuator via a pump. In recent years, instead of using an engine as a drive source, it has been proposed to use a system in which a battery is used as a drive source to drive the pump, or an electric motor in which each actuator is electrically driven by a battery, as shown in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-191450 Summary of the Invention [Problem to be solved by the invention]

[0004] When using an electric motor as described above, electric motors tend to be larger than hydraulic motors, so miniaturization is achieved by rotating the motor at high speed. However, high-speed rotation generates heat, particularly in the first-stage reduction gear directly connected to the motor shaft, making it necessary to cool these hot parts. For example, the above-mentioned Patent Document 1 discloses a configuration in which a fan and hood are provided on the input shaft side to forcibly cool the hot parts with air. However, in the case of a cooling system using a fan, the intake and exhaust ports are exposed, so soil and sand can get in when used in an environment such as construction machinery. Therefore, when cooling with a fan, it is difficult to install a miniaturized electric motor in construction machinery, etc., and there is room for improvement in this regard.

[0005] The present invention provides a reducer, actuator, and construction machine that are capable of high-speed rotation and miniaturization by suppressing heat generation in the reduction section using a fluid, and that are easy to mount on construction machinery and the like. [Means for solving the problem]

[0006] A reducer according to one embodiment of the present invention comprises a reduction section that reduces the rotational driving force of an electric motor and transmits it to a rotational driving section; a cylindrical case that houses the motor shaft of the electric motor and the reduction section and has a cylindrical axis facing the axial direction of the electric motor; a first flow path that is arranged along the axial direction of the case and through which a fluid flows; two plates that close both axial ends of the case; and a second flow path that is arranged on at least one of the two plates and through which the fluid flows and connects to the first flow path.

[0007] With this configuration, the first and second flow paths cool at least one of the two plates that close both ends of the case, and the reduction gear unit and motor shaft housed in the case are also cooled, making it possible to suppress heat generation in the reduction gear unit that is directly connected to the motor shaft. This allows the reduction gear unit to be adapted to handle high-speed rotation of the electric motor, and allows for the electric motor to be made smaller. In addition, the cooling method is achieved by providing a first flow path and a second flow path, which prevents soil and sand from getting mixed in when the intake and exhaust are exposed, as is the case with conventional air-cooling methods using fans, thereby improving the ease of installation on construction machinery and the like that is prone to soil and sand getting mixed in.

[0008] One of the two plates may be a heat dissipation carrier made of a heat sink, and the second flow path may be provided in the heat dissipation carrier.

[0009] It is desirable that a carrier gear provided in the speed reducer portion is rotatably supported on the heat dissipation carrier.

[0010] One of the two plates may be a motor flange attached to the electric motor, and the motor flange may be provided with an intake port and a discharge port connected to the first flow path.

[0011] It is desirable that the first flow path be gradually inclined from one end to the other end in the axial direction in a direction away from the rotation axis of the electric motor.

[0012] A reducer according to another aspect of the present invention comprises a reduction section that reduces the speed of the rotational drive force of an electric motor and transmits it to a rotational drive section; a cylindrical case that accommodates the motor shaft of the electric motor and the reduction section and has a cylindrical axis facing the axial direction of the electric motor; a first flow path that is provided in the case along the axial direction and through which a fluid flows; two plates that close both axial ends of the case; and a second flow path through which the fluid flows and connects to the first flow path, wherein the plate is provided on one side of the case and has a heat dissipation carrier consisting of a heat sink on which a carrier gear provided in the reduction section is rotatably supported; and a motor flange that is provided on the other side of the case and attached to the electric motor, wherein the second flow path is provided in the heat dissipation carrier, and the motor flange has an intake port and a discharge port that are connected to the first flow path, and the first flow path gradually inclined from one end in the axial direction to the other end in a direction away from the rotation axis of the electric motor.

[0013] With this configuration, the first and second flow paths cool at least one of the two plates closing both ends of the case, and the reduction gear and motor shaft housed in the case are also cooled, thereby suppressing heat generation in the reduction gear directly connected to the motor shaft. This allows the reduction gear to be adapted to high-speed rotation of the electric motor, enabling the electric motor to be made more compact. Furthermore, the cooling method using the first and second flow paths prevents soil and sand from getting into the air when the intake and exhaust ports are exposed, as is the case with conventional air-cooling methods using fans. This improves the ease of installation on construction machinery, which is prone to soil and sand getting in. In addition, a second flow path is provided in the heat dissipation carrier that suppresses heat generation in the reduction section, and the heat dissipation carrier is cooled by the fluid passing through the second flow path. Therefore, the reduction section including the carrier gear supported by the cooled heat dissipation carrier can be more reliably cooled, thereby suppressing heat generation in the reduction section. Furthermore, the reduction section including the carrier gear rotatably supported by the cooled heat dissipation carrier can be more reliably cooled, thereby suppressing heat generation in the reduction section. Furthermore, the fluid drawn in through the suction port flows unidirectionally through the first flow path and is discharged from the discharge port. In this way, the flow of the fluid flowing through the first and second flow paths can be unidirectional, and by connecting the suction port and discharge port to an external fluid supply unit with piping, the fluid can be circulated efficiently. Furthermore, an area where the first flow path is not disposed can be secured on the inner circumferential portion of one end or the other end of the cylindrical case, so that the speed reducer can be disposed in the area of ​​the case, thereby enabling the reduction gear to be made smaller.

[0014] An actuator according to one embodiment of the present invention comprises an electric motor, a reduction gear unit that reduces the speed of the rotational driving force of the electric motor and transmits it to a rotational driving unit, a cylindrical case that houses the motor shaft of the electric motor and the reduction gear unit and has a cylindrical axis facing the axial direction of the electric motor, a first flow path that is arranged along the axial direction of the case and through which a fluid flows, two plates that close both axial ends of the case, and a second flow path that is arranged on at least one of the two plates and through which the fluid flows and connects to the first flow path.

[0015] By configuring it in this manner, at least one of the two plates blocking both ends of the case is cooled by the first flow path and the second flow path, and the reduction gear, motor shaft, and electric motor housed in the case are also cooled, thereby suppressing heat generation in the reduction gear directly connected to the motor shaft.

[0016] A construction machine according to one embodiment of the present invention comprises a vehicle body, drive wheels that drive the vehicle body, and an electric motor and reducer that drive the drive wheels. The reducer comprises a reduction section that reduces the rotational drive force of the electric motor and transmits it to a rotational drive section, a cylindrical case that houses the motor shaft of the electric motor and the reduction section and has a cylindrical axis facing the axial direction of the electric motor, a first flow path that is arranged axially in the case and allows a fluid to flow, two plates that close both axial ends of the case, and a second flow path that is arranged in at least one of the two plates and through which the fluid flows and connects to the first flow path. The case is fixed to the vehicle body or the drive wheels, the rotational drive force of the electric motor is transmitted to the drive wheels via the reduction gear, and the first flow path and the second flow path are connected to a fluid supply section that is arranged in at least one of the vehicle body and the drive wheels.

[0017] With this configuration, the reducer can be provided in a state where the first flow path and the second flow path are connected to a fluid supply unit mounted on a construction machine such as a shovel. [Effects of the Invention]

[0018] The above-described reducer, actuator, and construction machine can be made compact and capable of high-speed rotation by suppressing heat generation in the reduction section, and can be easily mounted on construction machines and the like. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a side view of a shovel equipped with a reducer according to an embodiment. [Figure 2] 1 is a cross-sectional view of a reducer including an electric motor according to an embodiment; [Figure 3] FIG. 4 is a perspective view showing the second carrier, the first case, and the motor flange in an exploded view. [Figure 4] 3 is a view taken along the line AA in FIG. 2, showing a plan view of the input side end face of the first case. [Figure 5] 3 is a view taken along the line BB in FIG. 2, showing a plan view of the input side end face of the second carrier. DETAILED DESCRIPTION OF THE INVENTION

[0020] Next, embodiments of the present invention will be described with reference to the drawings. In the embodiments and modifications described below, the same reference numerals will be used to designate common parts, and some overlapping descriptions will be omitted.

[0021] FIG. 1 is a side view of a shovel 10 (construction machine) that employs a reducer 1 provided on an electric motor 2 in its drive section. The shovel 10 of this embodiment is a shovel that travels by a crawler, which is one form of a traveling body 12. The shovel 10 includes the traveling body 12 and a rotating body 11 that is installed on the traveling body 12 so as to be able to rotate.

[0022] The rotating body 11 is equipped with a driver's seat 13 in which an operator can sit, a boom 14 whose base end is rotatably supported in front of the driver's seat 13, an arm 15 whose base end is rotatably connected to the tip of the boom 14, and a bucket 16 rotatably connected to the tip of the arm 15. A drive device (not shown) is built into each joint of the operator's seat 13, boom 14, arm 15, and bucket 16. The drive device of each joint is driven by operation by the operator in the operator's seat 13. The traveling body 12 has a crawler body 121 (car body) and drive wheels 122 rotatably supported by the crawler body 121. The traveling body 12 is provided with an electric motor 2 equipped with a reduction gear 1 that drives the drive wheels 122.

[0023] Fig. 2 is a cross-sectional view (a view cut along a plane including a rotation axis O) of a reducer 1 equipped with an electric motor 2. Note that the shape and dimensions of the reducer 1 shown in Fig. 2 are merely examples and do not correspond to the actual dimensions.

[0024] The reducer 1 is connected to a reversible electric motor 2. The rotational driving force of the electric motor 2 is reduced in speed by the reducer 1 and output as rotational motion, which is transmitted to an axle provided on the drive wheels 122.

[0025] The reducer 1 has a two-stage reduction unit 4 made up of a planetary gear mechanism provided between a motor shaft 20 of the electric motor 2 and an axle. In the following description, the central axis of motor shaft 20 is referred to as rotation axis O, and the motor shaft 20 side in the rotation axis direction is referred to as the input side, and the opposite side is referred to as the output side. In addition, in a plan view of reducer 1 seen from the direction of rotation axis O, the direction perpendicular to rotation axis O is referred to as the radial direction, and the direction going around rotation axis O is referred to as the circumferential direction E.

[0026] The electric motor 2 has a motor shaft 20, a motor body 21, a motor case 22 that holds the motor body 21, and a motor flange 23 (plate) fixed to one end of the motor case 22. The motor shaft 20 extends in the direction of the rotation axis, and a tip portion 20a of one end (left side of the drawing) of the motor shaft 20 protrudes into the reducer 1. The electric motor 2 is attached to the reducer 1 via the motor flange 23. The motor flange 23 is formed in a plate shape, and when attached to the motor case 22, it projects radially outward from the motor case 22. As the electric motor 2, various motors that are driven by supplying electric power, such as a so-called brushed motor or brushless motor, can be used.

[0027] The reducer 1 has a first reduction gear unit 4A which is the first stage and a second reduction gear unit 4B which is the second stage in the order in which the rotational driving force is transmitted from the motor shaft 20. The arrangement of these reduction gear units 4 is such that the second reduction gear unit 4B and the first reduction gear unit 4A are arranged in this order from the input side to the output side in the direction of the rotation axis. The first reduction gear portion 4A and the second reduction gear portion 4B share a second case 5B, which will be described later, and are rotatably supported by the second case 5B.

[0028] The reducer 1 is provided with a cylindrical case 5 that houses the motor shaft 20 of the electric motor 2 and the reduction unit 4. The case 5 has a first case 5A on the input side and a second case 5B that is provided on the output side of the first case 5A and is rotatable relative to the first case 5A.

[0029] In this embodiment, the first case 5A is connected to the crawler body 121, and the second case 5B is connected to the drive wheels 122 of the traveling body 12. The connection between the first case 5A and the second case 5B and the excavator 10 is not limited to the above-described connection. For example, the second case 5B may be connected to the drive wheel 122, and the first case 5A may be connected to the crawler body 121. As a result, the rotational driving force of the electric motor 2 is transmitted to the traveling body 12 via the reducer 1.

[0030] The reducer 1 is fixed to an output side end surface 23b of a motor flange 23 of the electric motor 2 with fixing bolts 24. Specifically, the input side end portion (input side end surface 5a) of the first case 5A is attached to the motor flange 23. The first reduction chamber 1A and the second reduction chamber 1B inside the reducer 1 are sealed from the outside air, and the chambers are filled with lubricating oil.

[0031] The first case 5A is formed in a cylindrical shape with a bottom. The first case 5A is arranged coaxially with the rotation axis direction. The first case 5A has an inner cylindrical wall 51 and a bottom wall 52 arranged at the output side end of the inner cylindrical wall 51 so as to face the motor flange 23. The input side end surface 5a of the first case 5A is fixed to the motor flange 23 by a fixing bolt 24. In other words, the first case 5A is provided integrally with the electric motor 2 in a non-rotatable state. In this embodiment, the inner cylindrical wall 51 is provided with a first fixing portion 53 for fixing to the crawler body 121 of the excavator 10.

[0032] The bottom wall 52 has a first bearing 54 that rotatably supports the tip end 20a of the motor shaft 20. A second carrier 46 having a shaft portion 462 that rotatably supports the second gear 45 of the second reduction gear unit 4B is fixed to the output side end surface 52a of the bottom wall 52 with a bolt 463.

[0033] The second case 5B has an outer cylindrical wall 56 that rotatably fits in the circumferential direction against the outer peripheral surface 51a of the inner cylindrical wall 51 of the first case 5A via a second bearing 55. A lid 59 is attached to the opening on the output side (left side of the drawing) of the outer cylindrical wall 56, sealing the second speed reduction chamber 1B that is filled with lubricating oil.

[0034] A ring gear 57 is provided on the inner peripheral surface of the outer cylindrical wall 56. The ring gear 57 is disposed so as to mesh with both a plurality of first planetary gears 42 and a second gear 45, which will be described later. That is, the first planetary gear 42 and the second gear 45 share the second case 5B. In this embodiment, the outer cylinder wall 56 is provided with a second fixing portion 58 for fixing to the driving wheel 122 of the excavator 10.

[0035] A reduction input shaft 3 made of a shaft member connected to a motor shaft 20 that passes through the bottom wall 52 of the first case 5A is inserted into the second reduction chamber 1B.

[0036] As described above, the inside of the reducer 1 has the first reduction chamber 1A that forms the space inside the first case 5A and the second reduction chamber 1B that forms the space inside the second case 5B. The first reduction chamber 1A and the second reduction chamber 1B are separated by the bottom wall 52 of the first case 5A. The output-side tip 20a of the motor shaft 20 is inserted into and disposed in the first reduction chamber 1A. The tip 20a of the motor shaft 20 is connected to the reduction input shaft 3 coaxially with the motor shaft 20. The connection between the motor shaft 20 and the reduction input shaft 3 is disposed in the second reduction chamber 1B.

[0037] The first reduction unit 4A includes a first sun gear 41, a first planetary gear 42, and a first carrier 43. The first sun gear 41 is coaxially connected to the tip 3a on the output side (left side of the drawing) of the reduction input shaft 3. The first planetary gears 42 are arranged uniformly in the circumferential direction around the first sun gear 41. The first planetary gears 42 are arranged to mesh with the ring gear 57 of the second case 5B, and are rotatably supported by a shaft portion 431 provided on the first carrier 43. In other words, the first planetary gears 42 are arranged to mesh with both the first sun gear 41 and the second case 5B.

[0038] The first planetary gear 42 is coupled to the first carrier 43 by press-fitting a shaft portion 431. The first carrier 43 is formed in a flat ring shape. The first carrier 43 is rotatably supported on the reduction input shaft 3 at a position on the input side of the first planetary gear 42 in the direction of the rotation axis. The first carrier 43 is located between the first sun gear 41 and the second sun gear 44 in the direction of the rotation axis.

[0039] In the second reduction section 4B, the rotational driving force reduced in the first reduction section 4A is reduced in speed via the reduction input shaft 3, the first sun gear 41, the first planetary gear 42, and the first carrier 43, and is transmitted to the second sun gear 44 of the second reduction section 4B.

[0040] The second reduction gear portion 4B includes a second sun gear 44, a second gear (carrier gear) 45, and a second carrier 46 (plate). The second sun gear 44 has a hollow portion 44a through which the reduction input shaft 3 is inserted. The reduction input shaft 3 passes through both second sun gears 44, and the first sun gear 41 is coaxially fixed to the tip end portion 3a that passes through the second sun gear 44. The output side portion of the second sun gear 44 is non-rotatably engaged with the inner periphery of the first carrier 43, and the second sun gear 44 rotates integrally with the first carrier 43.

[0041] The second gears 45 are arranged uniformly in the circumferential direction around the second sun gear 44. The second gears 45 are arranged to mesh with the ring gear 57 of the second case 5B, and are rotatably supported by a shaft portion 462 that protrudes from the second carrier 46 toward the output side. In other words, the second gears 45 are arranged to mesh with both the second sun gear 44 and the second case 5B.

[0042] As shown in FIG. 3, the second carrier 46 is a heat dissipation carrier that includes a disk-shaped carrier body 460 and a heat sink 461 provided on the outer periphery of the carrier body 460.

[0043] In the second reduction section 4B, the rotational driving force reduced in the first reduction section 4A is reduced in speed via the second sun gear 44 and the second gear 45 and is then transmitted to the second case 5B.

[0044] 2, in the reducer 1 configured as above, when a rotational driving force is input from the motor shaft 20 rotated by the electric motor 2, the rotational driving force is transmitted to the reduction input shaft 3 coaxially connected to the motor shaft 20. When the rotational driving force is input to the reduction input shaft 3, the first planetary gear 42 rotates and revolves around the rotation axis O according to the difference in the number of teeth between the first sun gear 41 and the first planetary gear 42 in the first reduction section 4A and the difference in the number of teeth between the first planetary gear 42 and the ring gear 57 of the second case 5B. The rotational driving force input from the reduction input shaft 3 is then reduced in speed via the first carrier 43 that supports the first planetary gear 42 and transmitted to the second reduction section 4B.

[0045] Next, when a rotational drive force is input from the first carrier 43 of the first reduction gear unit 4A to the second sun gear 44 of the second reduction gear unit 4B, the second gear 45 rotates on its axis according to the difference in the number of teeth between the second sun gear 44 and the second gear 45 in the second reduction gear unit 4B and the difference in the number of teeth between the second gear 45 and the ring gear 57 of the second case 5B, and the second case 5B meshing with the second gear 45 rotates around the rotation axis O. In other words, the rotational drive force reduced from the second reduction gear unit 4B is transmitted to the second case 5B via the second gear 45. Then, the reduced rotational drive force can be extracted as an output from the drive wheel 122 of the excavator 10, which is fixed to the second fixing part 58 of the second case 5B.

[0046] 2 and 3, the first case 5A and the second carrier 46 are provided with a water-cooled water passage 6 (passage) for cooling the speed reducer 4. The motor flange 23 is provided with an intake port 61 and a discharge port 62 connected to the water-cooled water passage 6.

[0047] As shown in Figures 3, 4, and 5, the water-cooling flow path 6 is provided in the first case 5A along the rotational axis direction, and includes a plurality of axial flow paths 63 (first flow paths) arranged at intervals in the circumferential direction E to allow the flow of cooling water W, an output-side connecting flow path 64 (second flow path) arranged on the input-side end face 46a of the second carrier 46, and an input-side connecting flow path 65 (second flow path) arranged on the input-side end face 5a of the first case 5A.

[0048] The suction port 61 and the discharge port 62 are each bent in an L-shape from the outer peripheral surface 23a of the motor flange 23 and arranged toward the output-side end surface 23b. The suction port 61 draws cooling water W from the outside into the water-cooling passage 6. The discharge port 62 discharges the cooling water W that has flowed through the water-cooling passage 6 to the outside. The suction port 61 and the discharge port 62 are connected by piping to a water supply unit (fluid supply unit) (not shown) that is provided in a part of the above-mentioned excavator 10 shown in FIG. 1. Of the multiple axial passages 63 arranged in the circumferential direction, the side to which the suction port 61 is connected is the upstream side, and the side to which the discharge port 62 is connected is the downstream side.

[0049] As shown in Fig. 3, a plurality of axial flow passages 63 are arranged at intervals around almost the entire circumference in the circumferential direction E around the rotation axis O on the inner cylindrical wall 51 of the first case 5A. The input side end 63a of each axial flow passage 63 is located on the input side end face 5a of the first case 5A, and the output side end 63b is located on the output side end face 5b of the first case 5A. The input side end 63a of one of the plurality of axial flow passages 63 is connected to the suction port 61. The suction port 61 and the discharge port 62 are each connected to the input side end 63a of the axial flow passage 63 adjacent to each other in the circumferential direction E. The multiple axial flow passages 63 are gradually inclined in a direction away from the rotation axis O as they move from the output side to the input side (see FIG. 2).

[0050] As shown in FIGS. 3 and 4 , the output-side connecting passage 64 provided on the input-side end surface 46 a of the second carrier 46 is arranged along the circumferential direction E. A plurality of output-side connecting passages 64 are provided at intervals in the circumferential direction E. Both ends of the output-side connecting passage 64 in the longitudinal direction connect the output-side ends 63 b of the axial passages 63 adjacent in the circumferential direction E to each other. Of the pair of axial passages 63 connected to the output-side connecting passage 64, the output-side end 63 b of the axial passage 63 located on the upstream side (the suction port 61 side) through which the cooling water W flows is connected to the upstream end 64 a of the output-side connecting passage 64. Furthermore, the output-side end 63 b of the axial passage 63 located downstream is connected to the downstream end 64 b of the output-side connecting passage 64. In this way, of the pair of axial flow paths 63 connected to the output side connecting flow path 64, the cooling water W flows from the input side to the output side in the upstream axial flow path 63 in the circumferential direction E, and the cooling water W turns around at the output side connecting flow path 64 and circulates from the output side to the input side in the downstream axial flow path 63 in the circumferential direction E.

[0051] 3 and 5, the input-side connecting passage 65 provided on the input-side end surface 5a of the inner cylindrical wall 51 of the first case 5A is provided along the circumferential direction E. A plurality of input-side connecting passages 65 are provided at intervals in the circumferential direction E. Both ends of the input-side connecting passage 65 in the length direction connect the input-side ends 63a of the axial passages 63 adjacent to each other in the circumferential direction E. Of the pair of axial passages 63 connected to the input-side connecting passage 65, the axial passage 63 located upstream (on the suction port 61 side) is connected to a downstream end 64b of the output-side connecting passage 64, and the axial passage 63 located downstream is connected to an upstream end 64a of the output-side connecting passage 64. The input end 63a of the axial passage 63 located upstream is connected to an upstream end 65a of the input-side connecting passage 65. The input end 63a of the axial passage 63 located downstream is connected to a downstream end 65b of the input-side connecting passage 65. In this way, of the pair of axial passages 63 connected to the input-side connecting passage 65, the cooling water W flows from the output side to the input side in the upstream axial passage 63 in the circumferential direction E, and the cooling water W turns around at the input-side connecting passage 65 and circulates from the input side to the output side in the downstream axial passage 63 in the circumferential direction E. That is, the water-cooling passage 6 is formed by the axial passage 63, the output-side connecting passage 64, and the input-side connecting passage 65, and snakes in the direction of the rotation axis.

[0052] As described above, the reducer 1 of this embodiment comprises a reduction section 4 that reduces the rotational driving force of the electric motor 2 and transmits it to the rotational driving section, a cylindrical case 5 that houses the motor shaft 20 and reduction section 4 of the electric motor 2 and has its cylindrical axis facing the rotational axis direction of the electric motor 2, an axial flow path 63 that is provided in the case 5 along the rotational axis direction and through which cooling water W flows, two plates (motor flange 23, second carrier 46) that close both ends of the case 5 in the rotational axis direction, and an output side connecting flow path 64 and an input side connecting flow path 65 that are provided on at least one of the two plates and through which the cooling water W flows and connects to the axial flow path 63. Therefore, at least one of the two plates closing both ends of the case 5 is cooled by the axial flow passage 63, the output-side connecting flow passage 64, and the input-side connecting flow passage 65, and the speed reducer 4 and motor shaft 20 housed in the case 5 are also cooled, making it possible to suppress heat generation in the speed reducer 4, which is directly connected to the motor shaft 20. This makes it possible to adapt the speed reducer 4 to high-speed rotation of the electric motor 2, thereby enabling the electric motor 2 to be made more compact. Furthermore, the provision of the axial flow passage 63, the output-side connecting flow passage 64, and the input-side connecting flow passage 65 provides a cooling method that prevents soil and sand from getting mixed in when the intake and exhaust air is exposed, as is the case with conventional air-cooling methods using a fan, thereby improving the ease of installation on construction machinery and the like that is prone to soil and sand getting mixed in.

[0053] Furthermore, in the reducer 1 of this embodiment, the second carrier 46 is a heat dissipation carrier made up of a heat sink, and the output side connecting flow path 64 is provided in the second carrier 46. For this reason, the second carrier 46, which is a heat dissipation carrier that suppresses heat generation in the reduction unit 4, is provided with an output-side connecting flow path 64, and is cooled by the cooling water W that passes through the output-side connecting flow path 64. Therefore, the reduction unit 4, including the carrier gear (second gear 45) supported by the cooled second carrier 46, can be cooled more reliably, and heat generation in the reduction unit 4 can be suppressed.

[0054] Furthermore, in the reducer 1 of this embodiment, the second carrier 46 rotatably supports the second gear 45 provided in the reduction unit 4. Therefore, the reduction gear unit 4 including the second gear 45 rotatably supported by the cooled second carrier 46 can be cooled more reliably, and heat generation in the reduction gear unit 4 can be suppressed.

[0055] In addition, in the reducer 1 of this embodiment, one of the two plates is a motor flange 23 attached to the electric motor 2, and the motor flange 23 is provided with an intake port 61 and a discharge port 62 connected to an axial flow path 63. Therefore, the cooling water W sucked in from the suction port 61 flows in one direction through the axial flow passage 63 and is discharged from the discharge port 62. In this way, the flow of the cooling water W flowing through the axial flow passage 63, the output-side connecting flow passage 64, and the input-side connecting flow passage 65 can be made to flow in one direction, and by connecting the suction port 61 and the discharge port 62 to an external water supply unit (not shown) with piping, the cooling water W can be circulated efficiently.

[0056] Furthermore, in the reducer 1 of this embodiment, the axial flow passage 63 is gradually inclined in a direction away from the rotation axis O of the electric motor 2 from one end to the other end in the rotation axis direction. Therefore, an area (reference numeral 51A in FIG. 2) where the axial flow passage 63 is not arranged can be secured on the inner circumferential portion at one end or the other end of the cylindrical case 5. For example, a ring gear that meshes with a carrier gear can be provided in the area 51A of the first case 5A. Therefore, a speed reducer can be arranged in the area 51A of the first case 5, and the reducer 1 can be made smaller.

[0057] In this embodiment, the crawler body 121 (car body), drive wheels 122 that move the crawler body 121, and an electric motor 2 and a reducer 1 that drive the drive wheels 122, the reducer 1 including a speed reducer unit 4 that reduces the speed of the rotational driving force of the electric motor 2 and transmits it to the rotational drive unit, a cylindrical first case 5A that houses the motor shaft 20 of the electric motor 2 and the speed reducer unit 4 and has a cylindrical axis oriented in the axial direction of the electric motor 2, an axial flow path 63 that is provided in the first case 5A along the axial direction and that allows cooling water W to flow, and a first case 5A that closes both axial ends of the first case 5A. It comprises two plates (motor flange 23, second carrier 46), and an input side connecting passage 65 and an output side connecting passage 64 provided on at least one of the two plates, through which cooling water W flows and connects to the axial passage 63, the first case 5A is fixed to the crawler body 121 or the drive wheel 122, the rotational driving force of the electric motor 2 is transmitted to the drive wheel 122 via the reducer 1, and the input side connecting passage 65 and the output side connecting passage 64 are connected to a water supply unit provided on at least one of the crawler body 121 and the drive wheel 122. Therefore, the reducer 1 can be provided with the axial flow path 63, the input side connecting flow path 65, and the output side connecting flow path 64 connected to a water supply unit mounted on a construction machine such as a shovel 10.

[0058] The present invention is not limited to the above-described embodiment, and various design modifications are possible without departing from the spirit of the present invention. For example, in the above embodiment, the reducer 1 is equipped with two reduction sections 4A and 4B, but the number of reduction sections is not limited to two. For example, it is also possible to provide the first flow path and the second flow path described above in a reducer equipped with three or one reduction section. Furthermore, in this embodiment, cooling water W is used as an example of the fluid, but the fluid is not limited to water, and other fluids such as oil or other refrigerants may also be used.

[0059] Furthermore, in the above embodiment, the second case 5B is provided on the output side of the first case 5A in the direction of the rotation axis, and the second case 5B is supported so as to be freely rotatable relative to the first case 5A, but this is not limited to a configuration in which a second case 5B is provided.

[0060] In the above embodiment, the second carrier 46 and the motor flange 23 close both ends of the first case 5A, and the output-side connecting passage 64, which is the second flow passage, is provided in the second carrier 46, and the input-side second flow passage 65 is provided on the input-side end surface 5a of the first case 5A. However, the position of the second flow passage is not limited to this. For example, the input-side second flow passage (input-side connecting passage 65) may be provided on the motor flange 23. Alternatively, the output-side connecting passage 64 may not be provided on the second carrier 46 but may be provided on the output-side end surface 5b of the first case 5A.

[0061] Furthermore, in the above embodiment, the suction port 61 and the discharge port 62 are provided on the motor flange 23 attached to the first case 5A, but these suction port 61 and discharge port 62 may be provided, for example, on the first case 5A rather than on the motor flange 23.

[0062] Furthermore, although the present embodiment shows a planetary gear mechanism as an example of the reducer 1, the reducer is not limited to a planetary gear mechanism. For example, the cooling flow path described above can be applied to an eccentric oscillating reducer included in a planetary gear mechanism, or a reducer with a center crank mechanism. An eccentric oscillating reducer has multiple crankshafts arranged circumferentially around the center axis of the reducer, and is equipped with an oscillating motion of the external gear and a rotational take-out mechanism for the carrier. Furthermore, a center crank mechanism reducer is a mechanism in which a crankshaft is arranged coaxially with the center axis of the reducer, and the crankshaft imparts oscillating motion to the external gear, and the rotational motion of the external gear is taken out from the carrier pin. Note that the reducer of the present invention can also be applied to reducers equipped with both an eccentric oscillating type reducer and a center crank mechanism.

[0063] Furthermore, although the transmission mechanism is shown as a speed reducing relationship (speed reducer) in this embodiment, it may be a constant speed or speed increasing relationship.

[0064] Furthermore, in the above-described embodiment, the reduction gear 1 is described as being applied to a shovel 10, but the reduction gear of the present invention is not limited to this and can also be applied to construction machines other than shovels.

[0065] Among the embodiments disclosed in this specification, those that are configured with multiple objects may be integrated, and conversely, those that are configured with a single object may be divided into multiple objects. Regardless of whether they are integrated or not, it is sufficient that they are configured to achieve the object of the invention. [Explanation of symbols]

[0066] 1...Reduction gear, 2...Electric motor, 3...Reduction input shaft, 4...Reduction section, 4A...First reduction section, 4B ...second reduction section, 5...case, 5A...first case, 5B...second case, 6...water-cooled flow path (flow path ), 10... Shovel (construction machine), 20... Motor shaft, 23... Motor flange (plate 41...First sun gear, 42...First planetary gear, 43...First carrier, 44...Second sun gear gear, 45...second gear, 46...second carrier (plate), 51...inner cylinder wall, 53...first Fixed portion, 57... ring gear, 58... second fixed portion, 61... suction port, 62... discharge port, 63...Axial flow path (first flow path), 64...Output side connecting flow path (second flow path), 65...Input side connecting Flow path (second flow path), 121... crawler body (car body), 122... drive wheel, O... rotation axis

Claims

1. a speed reducer that reduces the rotational drive force of the electric motor and transmits the reduced speed to the rotation drive unit; a cylindrical case that accommodates a motor shaft of the electric motor and the reduction gear unit and has a cylindrical axis oriented in the axial direction of the electric motor; a first flow path provided in the case along the axial direction and through which a fluid flows; two plates closing both axial ends of the case; a second flow path provided in at least one of the two plates, through which the fluid flows and which connects to the first flow path; A reducer comprising:

2. One of the two plates is a heat dissipation carrier made of a heat sink, The reducer according to claim 1 , wherein the second flow path is provided in the heat dissipation carrier.

3. The reducer according to claim 2 , wherein a carrier gear provided in the reduction section is rotatably supported by the heat dissipation carrier.

4. one of the two plates is a motor flange attached to the electric motor; The reducer according to claim 1 , wherein the motor flange is provided with an intake port and a discharge port connected to the first flow path.

5. The reducer according to claim 1 , wherein the first flow passage is gradually inclined from one end to the other end in the axial direction in a direction away from the rotation axis of the electric motor.

6. a speed reducer that reduces the rotational drive force of the electric motor and transmits the reduced speed to the rotation drive unit; a cylindrical case that accommodates a motor shaft of the electric motor and the reduction gear unit and has a cylindrical axis oriented in the axial direction of the electric motor; a first flow path provided in the case along the axial direction and through which a fluid flows; two plates closing both axial ends of the case; a second flow path provided in at least one of the two plates, through which the fluid flows and which connects to the first flow path; The plate is a heat dissipation carrier provided on one side of the case and including a heat sink on which a carrier gear provided in the reduction gear unit is rotatably supported; a motor flange provided on the other side of the case and attached to the electric motor, the second flow path is provided in the heat dissipation carrier, the motor flange is provided with an intake port and a discharge port connected to the first flow path, The first flow path is gradually inclined from one end to the other end in the axial direction in a direction away from the rotation axis of the electric motor.

7. An electric motor; a speed reducer that reduces the rotational drive force of the electric motor and transmits the reduced rotational drive force to a rotation drive unit; a cylindrical case that accommodates a motor shaft of the electric motor and the reduction gear unit and has a cylindrical axis oriented in the axial direction of the electric motor; a first flow path provided in the case along the axial direction and through which a fluid flows; two plates closing both axial ends of the case; a second flow path provided in at least one of the two plates, through which the fluid flows and which connects to the first flow path; An actuator comprising:

8. The car body and drive wheels for driving the vehicle body; an electric motor and a reducer that drive the drive wheels; Equipped with The reducer is a speed reducer that reduces the rotational drive force of the electric motor and transmits the reduced speed to the rotation drive unit; a cylindrical case that accommodates a motor shaft of the electric motor and the reduction gear unit and has a cylindrical axis oriented in the axial direction of the electric motor; a first flow path provided in the case along the axial direction and through which a fluid flows; two plates closing both axial ends of the case; a second flow path provided in at least one of the two plates, through which the fluid flows and which connects to the first flow path; Equipped with the case is fixed to the vehicle body or the drive wheels, and the rotational drive force of the electric motor is transmitted to the drive wheels via the reducer; The first flow path and the second flow path are connected to a fluid supply unit provided in at least one of the vehicle body and the drive wheels.

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