Reducer and construction machinery

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 for reducing rotation driving force of an electric motor 2 and transmitting the same to a rotation driving portion; and a ring gear 5A engaged with a gear decelerated by the speed reduction portion 4 near the electric motor 2 in a rotation axial direction of the electric motor 2. The ring gear 5A is provided with a water-cooling flow channel 6 in which cooling water W flows, and includes the other ring gear 5B rotatably supported to the ring gear 5A, the water-cooling flow channel 6 is extended in a C-shape when observing the ring gear 5A from the rotation axial direction, and includes a first groove 63 having a shallow depth, and at least one second groove 64 having a depth deeper than the first groove 63 and formed on a part of the first groove 63. The ring gear 5A is provided with a motor flange 23 mounted on the electric motor 2, and the motor flange 23 is provided with a suction port 61 and a discharge port 62 connected to the water-cooling flow channel 6.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a reducer 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 using 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 and construction machine that can be miniaturized and rotates at high speeds by suppressing heat generation in the reduction section using a fluid, and that is easy to mount on construction machines and the like. [Means for solving the problem]

[0006] A speed reducer according to one aspect of the present invention includes a speed reducer unit that reduces the speed of a rotational driving force of an electric motor and transmits the reduced speed to a rotational driving unit; Ring gear a flow path through which a fluid flows, The flow path is provided in a C-shape when the ring gear is viewed from the rotational axis direction of the electric motor, and the flow path includes a first groove having a shallow depth and at least one second groove that is deeper than the first groove and is provided in a part of the first groove. do.

[0007] With this configuration, the gears are cooled by the flow path, which reduces heat generation in the reduction section directly connected to the motor shaft, making it possible to adapt the reduction section to high-speed rotation of the electric motor and enabling the electric motor to be made smaller. In addition, the cooling method uses a 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-cooled systems using fans, thereby improving the ease of installation on construction machinery and other equipment that is prone to soil and sand getting mixed in. Furthermore, in areas where it is necessary to ensure the meshing strength of the gears in the reduction section, deeper second grooves can be provided partially rather than providing grooves all around the circumference. That is, shallower first grooves can be provided in areas where the meshing strength has little effect, allowing fluid to circulate, while the gears that require cooling can also be cooled by the fluid that has entered the second grooves.

[0008] The reduction gear includes a plurality of stages of reduction gear units, and the reduction gear unit closest to the input side of the reduction gear unit is the reduction gear unit to which the rotational driving force of the electric motor is transmitted. Ring gear It is desirable that the flow path is provided in the

[0009] the reduction gear unit includes a sun gear to which the rotational driving force of the electric motor is input; the sun gear and a planet gear provided between the sun gear and the ring gear and meshing with the sun gear and the ring gear, The ring gear is formed to surround the periphery of the sun gear and has internal teeth. It is desirable.

[0011] The second groove is predetermined interval A plurality of such electrodes may be provided with an interval therebetween.

[0012] The second groove The number of the planetary gears may be different from that of the rotor.

[0013] The aforementioned The input end face of the ring gear has The flange Fixed The flange may be provided with an intake port and a discharge port connected to the flow path.

[0014] The flange is preferably attached to the electric motor.

[0015] According to another aspect of the present invention, there is provided a speed reducer including: a speed reducer section for reducing the rotational driving force of an electric motor and transmitting the reduced rotational driving force to a rotational driving section; Ring gear a flow path through which a fluid flows, the flow path is provided in a C-shape when the ring gear is viewed from the rotational axis direction of the electric motor, and the flow path includes a first groove having a shallow depth and at least one second groove that is deeper than the first groove and is provided in a part of the first groove; The reduction gear includes a plurality of stages of reduction gear units, and the reduction gear unit closest to the input side of the reduction gear unit is the reduction gear unit to which the rotational driving force of the electric motor is transmitted. Ring gear the flow path is provided in the reduction gear unit, and the reduction gear unit includes a sun gear to which the rotational driving force of the electric motor is input; the sun gear and a planet gear provided between the sun gear and the ring gear and meshing with the sun gear and the ring gear, the ring gear is formed to surround the periphery of the sun gear and has internal teeth; The second grooves are provided in plurality at predetermined intervals, and the number of the second grooves and the number of the planetary gears are different. Input end face of ring gear The flange attached to the electric motor Fixed The flange is provided with an intake port and a discharge port connected to the flow path.

[0016] With this configuration, the gears cooled by the flow passages are cooled, thereby suppressing heat generation in the reduction gear section directly connected to the motor shaft. This allows the reduction gear section to be adapted to handle high-speed rotation of electric motors, enabling the electric motor to be made more compact. Furthermore, the cooling method using flow passages prevents soil and sand from getting mixed in with the intake and exhaust air, which is the case with conventional air-cooled systems using fans, and therefore improves the ease of installation on construction machinery and other equipment prone to soil and sand getting mixed in. Furthermore, since a flow path is provided in the gear of the reduction gear section on the input side among the multiple stages of reduction gear sections, the reduction gear section on the input side, which rotates the fastest and is prone to become hot, can be cooled efficiently. Furthermore, the gear can be fixed so that it cannot rotate, and the piping structure connecting the fluid supply unit mounted on the construction machine or the like to the flow path can be simplified. Furthermore, in areas where it is necessary to ensure the meshing strength of the gears in the reduction section, deeper second grooves can be provided partially rather than providing grooves all around the circumference. That is, shallower first grooves can be provided in areas where the meshing strength has little effect, allowing fluid to circulate, while the gears that require cooling can also be cooled by the fluid that has entered the second grooves. Furthermore, the flow of the fluid circulating within the flow path can be made unidirectional, and by connecting the intake port and discharge port to an external fluid supply unit with piping, the fluid can be circulated efficiently. Furthermore, since the flange is attached to the electric motor, the electric motor connected to the motor flange can also be cooled, thereby suppressing heat generation from the electric motor itself.

[0017] A construction machine according to one aspect of the present invention includes a vehicle body, drive wheels for driving the vehicle body, an electric motor for driving the drive wheels, and a speed reducer, the speed reducer including a speed reducer section for reducing the rotational drive force of the electric motor and transmitting the reduced rotational drive force to a rotation drive section, and a speed reducer section for reducing the rotational drive force of the speed reducer. Ring gear a flow path through which a fluid flows, the flow path is provided in a C-shape when the ring gear is viewed from the rotational axis direction of the electric motor, and the flow path includes a first groove having a shallow depth and at least one second groove that is deeper than the first groove and is provided in a part of the first groove; The aforementioned Ring gear is fixed to the vehicle body or the drive wheel, the rotational driving force of the electric motor is transmitted to the drive wheel via the reducer, and the flow path is connected to a fluid supply unit provided on at least one of the vehicle body and the drive wheel.

[0018] With this configuration, the reducer can be provided with the flow path connected to the fluid supply unit mounted on the construction machine. [Effects of the Invention]

[0019] The above-described reducer 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]

[0020] [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. 2 is a perspective view of the first ring gear and the motor flange separated from each other. [Figure 4] 3 is a view taken along the line AA in FIG. 2, showing a plan view of the first ring gear as seen from the axial direction. DETAILED DESCRIPTION OF THE INVENTION

[0021] 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.

[0022] 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.

[0023] The rotating body 11 includes 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. Each joint of the driver's seat 13, boom 14, arm 15, and bucket 16 has a built-in drive device (not shown). The drive device of each joint is driven by operation by the operator in the driver'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.

[0024] 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.

[0025] 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.

[0026] The reducer 1 has a three-stage reduction section 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 the motor shaft 20 is referred to as the rotation axis O, and the motor shaft 20 side in the direction of the rotation axis is referred to as the input side, and the opposite side is referred to as the output side.

[0027] 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 fixed to one end of the motor case 22. The motor shaft 20 extends in the motor axial direction through the center of the motor body 21, 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.

[0028] The reducer 1 has a first reduction gear unit 4A as the first stage, a second reduction gear unit 4B as the second stage, and a third reduction gear unit 4C as the third stage in the order in which the rotational driving force from the motor shaft 20 is transmitted. These reduction gear units 4 are arranged in the order of first reduction gear unit 4A, third reduction gear unit 4C, and second reduction gear unit 4B from the input side to the output side in the direction of the rotation axis. In other words, the third reduction gear unit 4C is arranged between the first reduction gear unit 4A and the second reduction gear unit 4B. The first reduction gear portion 4A is rotatably supported by a first ring gear 5A (gear), and the second reduction gear portion 4B and the third reduction gear portion 4C share the second ring gear 5B and are rotatably supported by the second ring gear 5B.

[0029] In this embodiment, the first ring gear 5A is connected to the crawler body 121, and the second ring gear 5B is connected to the driving wheels 122 of the traveling body 12, as shown in FIG. The connection between the first ring gear 5A and the second ring gear 5B and the shovel 10 is not limited to the above-described connection. For example, the second ring gear 5B may be connected to the drive wheel 122, and the first ring gear 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 by a fixing bolt 24. Specifically, an input side end portion (input side end surface 501a) of the first ring gear 5A is attached to the motor flange 23. A first reducer chamber 1A inside the reducer 1 is sealed from the outside air, and the chamber is filled with lubricating oil.

[0031] The first ring gear 5A is formed in a cylindrical shape with a bottom. The first ring gear 5A has an inner cylindrical wall 501 arranged coaxially with the rotation axis direction, and a bottom wall 502 arranged opposite the motor flange 23 and closing the output side end of the inner cylindrical wall 501. An input side end surface 501a of the inner cylindrical wall 501 is fixed to the motor flange 23 by a fixing bolt 24. In other words, the first ring gear 5A is provided integrally with the electric motor 2 in a non-rotatable state. A first bearing 51 that rotatably supports the motor shaft 20 by inserting it through is provided at an opening of the inner cylindrical wall 501 on the electric motor 2 side. A first internal gear 52 is provided on the inner circumferential surface of the input side of the inner cylindrical wall 501. A plurality of first planetary gears 42 are arranged to mesh with the first internal gear 52.

[0032] In this way, the first ring gear 5A is not attached to the rotating motor shaft 20, but is a fixed gear fixed to the motor flange 23 fixed to the motor case 22.

[0033] In this embodiment, the inner cylindrical wall 501 is provided with a first fixing portion 55 for fixing to the crawler body 121 of the excavator 10.

[0034] The bottom wall 502 of the first ring gear 5A is provided with a second bearing 53 that rotatably supports the reduction input shaft 3 made of a shaft member, and a rotation support pillar 54 that rotatably supports the third gear 48 of the third reduction unit 4C. The rotation support pillar 54 is provided so as to protrude integrally with the output side end face 502a of the bottom wall 502 in the direction of the rotation axis.

[0035] The second ring gear 5B has an outer cylindrical wall 503 that rotatably fits in the circumferential direction against the outer peripheral surface 501b of the inner cylindrical wall 501 of the first ring gear 5A via a third bearing 56. A lid 504 is attached to the opening on the output side (left side of the drawing) of the outer cylindrical wall 503, sealing the second reducer chamber 1B filled with lubricating oil.

[0036] A second internal gear 57 is provided on the inner peripheral surface of the outer cylinder wall 503. The second internal gear 57 is arranged so as to mesh with both a plurality of second planetary gears 45 and a third gear 48, which will be described later. In other words, the second ring gear 5B is shared by the second planetary gears 45 and the third gear 48. The second ring gear 5B is a stepped gear, and a large diameter gear 57A of the second internal gear 57, which meshes with the second planetary gears 45, has an inner diameter dimension set to be larger than that of a small diameter gear 57B, which meshes with the third gear 48. In this embodiment, the outer cylinder wall 503 is provided with a second fixing portion 58 for fixing to the driving wheel 122 of the excavator 10. The large diameter gear 57A with which the second reduction gear portion 4B meshes and the small diameter gear 57B with which the third reduction gear portion 4C meshes are provided so as to be unable to rotate relative to each other.

[0037] The reduction input shaft 3, which passes through the bottom wall 502 of the first ring gear 5A, and a rotation support column 54, which is fixed to the bottom wall 502, are inserted into the second reduction gear chamber 1B.

[0038] As described above, the inside of the reducer 1 has a first reducer chamber 1A that forms the space inside the first ring gear 5A, and a second reducer chamber 1B that forms the space inside the second ring gear 5B. The first reducer chamber 1A and the second reducer chamber 1B are separated by a bottom wall 502 of the first ring gear 5A. The output side of the motor shaft 20 is inserted into the first reducer chamber 1A. The reduction input shaft 3 is connected coaxially to the tip end 20a of the motor shaft 20.

[0039] The first reduction gear 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 motor shaft 20. A plurality of first planetary gears 42 are evenly arranged in the circumferential direction around the first sun gear 41. The first planetary gears 42 are arranged to mesh with the first internal gear 52 of the first ring gear 5A, and are rotatably supported by a shaft portion 421 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 first ring gear 5A.

[0040] The shaft portion 421 of the first planetary gear 42 is coupled to the first carrier 43 by being press-fitted. The first carrier 43 is formed in a flat ring shape. The first carrier 43 is fixed coaxially with the motor shaft 20 at a position on the output side of the first planetary gear 42 in the direction of the rotation axis, with its rotation restricted relative to the reduction input shaft 3. The connection portion between the motor shaft 20 and the reduction input shaft 3 is located between the first sun gear 41 and the first carrier 43.

[0041] In the first reduction section 4A, the rotational driving force of the electric motor 2 is reduced in speed via the motor shaft 20, the first sun gear 41, the first planetary gear 42, and the first carrier 43 and is then transmitted to the reduction input shaft 3.

[0042] The second reduction unit 4B includes a second sun gear 44, a second planetary gear 45, and a second carrier 46. The second sun gear 44 is coaxially connected to the tip 3a on the output side (left side of the drawing) of the reduction input shaft 3. Multiple second planetary gears 45 are evenly arranged circumferentially around the second sun gear 44. The second planetary gears 45 are arranged to mesh with the second internal gear 57 (large diameter gear 57A) of the second ring gear 5B, and are rotatably supported by a shaft portion 461 provided on the second carrier 46. In other words, the second planetary gears 45 are arranged to mesh with both the second sun gear 44 and the second ring gear 5B.

[0043] The shaft portion 461 of the second planetary gear 45 is coupled to the second carrier 46 by being press-fitted. The second carrier 46 is formed in a flat ring shape. The second carrier 46 is fixed coaxially with the motor shaft 20 in a state where it can rotate freely relative to the reduction input shaft 3, at a position on the input side of the second planetary gear 45 in the direction of the rotation axis. The second carrier 46 is located between the second sun gear 44 and the third sun gear 47 in the direction of the motor shaft.

[0044] 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 second sun gear 44, the second planetary gear 45, and the second carrier 46, and is transmitted to the third sun gear 47 of the third reduction section 4C.

[0045] The third reduction gear portion 4C includes a third sun gear 47 and a third gear . The third sun gear 47 has a hollow portion 47a through which the reduction input shaft 3 is inserted. The reduction input shaft 3 passes through both the first carrier 43 and the third sun gear 47, and the second sun gear 44 is coaxially fixed to the tip end portion 3a that passes through the third sun gear 47. The third sun gear 47 is non-rotatably engaged with the inner periphery 46a of the second carrier 46 on the output side and is provided integrally therewith. The third sun gear 47 rotates together with the second carrier 46.

[0046] The third gears 48 are arranged uniformly in the circumferential direction around the third sun gear 47. The third gears 48 are arranged to mesh with the second internal gear 57 (small diameter gear 57B) of the second ring gear 5B, and are rotatably supported by a rotation support column 54 that protrudes from the bottom wall 502 of the first ring gear 5A toward the output side. In other words, the third gears 48 are arranged to mesh with both the third sun gear 47 and the second ring gear 5B.

[0047] In the third reduction section 4C, the rotational driving force reduced in the second reduction section 4B is reduced in speed via the third sun gear 47 and the third gear 48 and transmitted to the second ring gear 5B.

[0048] 2 and 3, the first ring gear 5A is provided with a water-cooling flow passage 6 (flow passage) for cooling the first reduction gear part 4A. The motor flange 23 is provided with an intake port 61 and a discharge port 62 connected to the water-cooling flow passage 6. The water-cooling passage 6 is disposed in the first ring gear 5A and is connected to an intake port 61 and a discharge port 62.

[0049] 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 (fluid) 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 (not shown) that is equipped on a part of the above-mentioned shovel 10.

[0050] As shown in Fig. 4, the water-cooling channel 6 is disposed on an input-side end surface 501a of the inner cylindrical wall 501 of the first ring gear 5A, which faces the motor flange 23. A water-stopping member such as an O-ring (not shown) that makes liquid-tight contact with the motor flange 23 is provided on an outer peripheral edge 501c that is outer circumferential of the water-cooling channel 6 when viewed from the direction of the rotation axis. The water-cooling channel 6 extends in a C-shape when viewed from the direction of the rotation axis. The water-cooling channel 6 has a shallow first groove 63 and a plurality of (four in this example) second grooves 64 that are deeper than the first groove 63 and are located in part of the first groove 63. Here, the C-shape of the water-cooling channel 6 mentioned above is a shape in which a part of a substantially circular shape is cut out in the circumferential direction. The length of the cutout is not particularly limited. The substantially circular shape indicating the shape of the water-cooling channel 6 may be, for example, an elliptical shape or a polygonal shape. In this embodiment, the direction of the C-shaped groove-free portion of the water-cooling flow path 6 (the portion where the intake port 63a and the discharge port 63b described later are located) is upward, but is not particularly limited thereto and may be downward or horizontal, for example.

[0051] The second groove 64 is a groove that is deeper than the bottom 63c of the first groove 63 and is positioned in the rotational axis direction so as to reach the vicinity of the first internal gear 52 that meshes with the first planetary gear 42 of the first reduction gear unit 4A, as shown in FIG. 2. An intake port 61 is connected to an intake port 63a at one end of the water-cooling flow path 6 in the extension direction, and an outlet port 63b at the other end is connected to an outlet port 63b. The cooling water W sucked in from the intake port 63a of the water-cooling flow path 6 flows toward the outlet port 63b (in the direction of the arrow shown in FIGS. 3 and 4) and is discharged from the outlet port 63b. At this time, the cooling water W that has flowed into the first groove 63 permeates into the four second grooves 64.

[0052] 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 first planetary gear 42 rotates on its axis and revolves around the rotation axis O in accordance with the difference in the number of teeth between the first sun gear 41 and the first planetary gear 42 in the first reduction unit 4A and the difference in the number of teeth between the first planetary gear 42 and the first internal gear 52 of the first ring gear 5A. Then, the rotational driving force reduced from the first reduction unit 4A is transmitted to the reduction input shaft 3 via the first carrier 43 that supports the first planetary gear 42.

[0053] Next, when a rotational driving force is input from the first reduction gear unit 4A to the reduction input shaft 3 coupled to the motor shaft 20, the second planetary gear 45 rotates on its axis and revolves around the rotation axis O according to the difference in the number of teeth between the second sun gear 44 and the second planetary gear 45 in the second reduction gear unit 4B fixed to the tip end 3a of the reduction input shaft 3 and the difference in the number of teeth between the second planetary gear 45 and the second ring gear 5B (large diameter gear 57A). Then, the rotational driving force reduced from the second reduction gear unit 4B is transmitted to the third sun gear 47 of the third reduction gear unit 4C via the second carrier 46 that supports the second planetary gear 45.

[0054] Next, when a rotational drive force is input from the second carrier 46 of the second reduction gear unit 4B to the third sun gear 47 of the third reduction gear unit 4C, the third gear 48 rotates on its axis according to the difference in the number of teeth between the third sun gear 47 and the third gear 48 in the third reduction gear unit 4C and the difference in the number of teeth between the third gear and the second ring gear 5B (small diameter gear 57B), and the second ring gear 5B meshing with the third gear 48 rotates around the rotation axis O. In other words, the rotational drive force reduced from the third reduction gear unit 4C is transmitted to the second ring gear 5B via the third gear 48. 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 fixed portion 58 of the second ring gear 5B.

[0055] As described above, the reducer 1 of this embodiment includes a reduction section 4 that reduces the rotational driving force of the electric motor 2 and transmits it to the rotational driving section, and a water-cooling flow path 6 that is provided in the first ring gear 5A and through which a fluid (cooling water W) flows. Therefore, the first reduction gear 4A that meshes with the first ring gear 5A that is cooled by the water-cooling flow path 6 is also cooled, which makes it possible to suppress heat generation in the first reduction gear 4A that is directly connected to the motor shaft 20. As a result, the first reduction gear 4A can be adapted to handle high-speed rotation of the electric motor 2, making it possible to reduce the size of the electric motor 2. Furthermore, the provision of the water-cooling flow path 6 results in a water-cooled cooling system, which prevents soil and sand from getting mixed in when the intake and exhaust are exposed, as is the case with conventional air-cooled systems that use fans, and therefore makes it easier to install on construction machinery and the like that is prone to soil and sand getting mixed in.

[0056] In addition, the reducer 1 of this embodiment has a multi-stage reduction section 4, and a water-cooling flow path 6 is provided in the gear (first ring gear 5A) of the first reduction section 4A, which is the most input side of these multi-stage reduction sections 4. Therefore, the first reduction gear portion 4A on the input side, which rotates the fastest and is most likely to become hot, can be cooled efficiently.

[0057] In addition, in the reducer 1 of this embodiment, the reduction section 4 includes a sun gear to which the rotational driving force of the electric motor 2 is input, a ring gear 5 formed to surround the periphery of the sun gear and having internal teeth, and a planetary gear provided between the sun gear and the ring gear 5 and meshing with the sun gear and the ring gear 5, the gear being the first ring gear 5A. This allows the first ring gear 5A to be fixed so that it cannot rotate, simplifying the piping structure connecting the water supply unit mounted on a construction machine such as the shovel 10 of this embodiment to the water-cooled flow path 6.

[0058] Furthermore, in the reducer 1 of this embodiment, the water-cooled flow path 6 is formed in a C-shape when the first ring gear 5A is viewed from the direction of the rotational axis of the electric motor 2, and the water-cooled flow path 6 has a shallow first groove 63 and at least one second groove 64 deeper than the first groove 63 in a part of the first groove 63. For this reason, in an area (part of the first internal gear 52) where it is necessary to ensure the meshing strength of the gear (first planetary gear 42) of the first reduction gear portion 4A, it is possible to provide deeper second grooves 64 partially rather than providing grooves all around the circumference. In other words, shallow first grooves 63 are provided in the area where the meshing strength has little effect as described above, and cooling water W is circulated therethrough, while the cooling water W that has entered the second grooves 64 can also be used to cool the parts of the first internal gear 52 that require cooling.

[0059] Furthermore, in the reducer 1 of this embodiment, a plurality of second grooves 64 are provided at predetermined intervals. Therefore, if a second groove that is deeper than the first groove is provided, it is expected that the rigidity of the first ring gear 5A (fixed gear) will decrease and the outer diameter of the first ring gear 5A will become larger. However, by providing the second groove partially in the circumferential direction, it is possible to prevent the rigidity of the first ring gear 5A from decreasing and the diameter from becoming larger.

[0060] Furthermore, in the reducer 1 of this embodiment, first planetary gears 42 that mesh with the first ring gear 5A are provided, and the number of second grooves 64 and the number of first planetary gears 42 are different. That is, in this embodiment, four second grooves 64 are provided in the circumferential direction of the first grooves 63, and one planetary gear 42 meshes with the first ring gear 5A. By setting the numbers of second grooves 64 and first planetary gears 42 to be different in this way, it is possible to prevent vibrations caused by the same phase as when the numbers of second grooves and planetary gears are the same.

[0061] In the reducer 1 of this embodiment, the first ring gear 5A is provided with a motor flange 23, and the motor flange 23 is provided with an intake port 61 and a discharge port 62 connected to the water-cooling passage 6. Therefore, the cooling water W drawn in from the suction port 61 flows in one direction through the water-cooling passage 6 and is discharged from the discharge port 62. In this way, the flow of the cooling water W circulating in the water-cooling passage 6 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.

[0062] Furthermore, in the reducer 1 of this embodiment, the motor flange 23 is attached to the electric motor 2, so that the electric motor 2 connected to the motor flange 23 can also be cooled. Therefore, heat generation from the electric motor 2 itself can also be suppressed.

[0063] Moreover, in this embodiment, the vehicle includes a 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 includes a speed reducer 4 that reduces the rotational drive force of the electric motor 2 and transmits it to the rotational drive unit, and a water-cooling flow path 6 that is provided in a first ring gear 5A and through which cooling water W flows. The first ring gear 5A is fixed to the crawler body 121 or the drive wheels 122. The rotational drive force of the electric motor 2 is transmitted to the drive wheels 122 via the reducer 1. The water-cooling flow path 6 is connected to a water supply unit that is provided in at least one of the crawler body 121 and the drive wheels 122. Therefore, the reducer 1 can be provided with the water-cooling passage 6 connected to a water supply unit mounted on a construction machine such as a shovel 10 .

[0064] 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 three reduction sections 4A, 4B, and 4C, but the number of reduction sections is not limited to three. For example, the water-cooling passage 6 can be provided in a reducer equipped with two or one reduction sections. 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.

[0065] In addition, in the above embodiment, the target for providing the water-cooling flow passage 6 (flow passage) is the first ring gear 5A, but it is not limited to the first ring gear 5A, which is a fixed gear. Any gear can be provided with a flow passage, and for example, in the case of a planetary gear mechanism as in the above embodiment, even a sun gear or planetary gear, in addition to the ring gear, can be an applicable target for achieving the object of the present invention by providing a structure for dynamically changing the connection of the flow passage.

[0066] In addition, in the above embodiment, a second ring gear 5B is provided on the output side of the first ring gear 5A in the direction of the rotation axis, and the second ring gear 5B is supported rotatably relative to the first ring gear 5A, but this is not limited to a configuration in which a second ring gear 5B is provided.

[0067] In the above embodiment, the water-cooling flow channel 6 has a flow channel shape including a shallow first groove 63 extending in a C-shape and at least one second groove 64 deeper than the first groove 63 in a part of the first groove 63, but is not limited to such a two-stage groove shape and can have other flow channel shapes. Also, the grooves may have a multi-stage structure of three or more stages instead of a two-stage structure.

[0068] Furthermore, in the above embodiment, the intake port 61 and the discharge port 62 are provided on the motor flange 23 attached to the first ring gear 5A, but these intake port 61 and discharge port 62 may be provided on, for example, the first ring gear 5A rather than on the motor flange 23.

[0069] Furthermore, although the present embodiment illustrates a planetary gear mechanism as an example of the reducer 1, the present invention 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 center crank mechanism reducer. An eccentric oscillating reducer is a mechanism in which multiple crankshafts are arranged circumferentially around the center axis of the reducer and which is equipped with a mechanism for oscillating motion of the external gear and rotating motion of the carrier. A center crank mechanism reducer is a mechanism in which a crankshaft is arranged coaxially with the center axis of the reducer and adds oscillating motion to the external gear, and the rotating motion of the external gear is extracted from the carrier pin. Note that the reducer of the present invention can also be applied to a reducer equipped with both an eccentric oscillating reducer and a center crank mechanism.

[0070] 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.

[0071] 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.

[0072] 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]

[0073] 1...reduction gear, 2...electric motor, 3...reduction input shaft, 4...reduction section, 4A...first reduction section, 4B...second reduction section, 4C...third reduction section, 5...ring gear (gear), 5A...first ring gear, 5B...second ring gear, 6...water-cooled flow path (flow path), 10...shovel (construction machine), 12...traveling body, 41...first sun gear, 42...first planetary gear, 43...first carrier, 44 ...Second sun gear, 45...Second planetary gear, 46...Second carrier, 47...Third sun gear, 48...Third gear, 52...First internal gear, 54...Rotation support column, 55...First fixed portion, 57...Second internal gear, 58...Second fixed portion, 61...Suction port, 62...Discharge port, 63...First groove, 64...Second groove, 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 flow path provided in a ring gear of the reduction gear unit, through which a fluid flows; the flow path is provided in a C-shape when the ring gear is viewed from the rotational axis direction of the electric motor, The flow path is a shallow first groove; At least one second groove deeper than the first groove is formed in a part of the first groove; A reducer comprising:

2. The reduction gear unit includes a plurality of stages, The reducer according to claim 1 , wherein the flow path is provided in the ring gear of the reduction gear unit on the most input side to which the rotational driving force of the electric motor is transmitted, among the multiple reduction gear units.

3. The speed reducer is a sun gear to which the rotational driving force of the electric motor is input; a planetary gear provided between the sun gear and the ring gear and meshing with the sun gear and the ring gear; Equipped with The reducer according to claim 1 or 2, wherein the ring gear is formed so as to surround the periphery of the sun gear and has internal teeth.

4. The reducer according to claim 1 , wherein a plurality of the second grooves are provided at predetermined intervals.

5. A reducer as described in claim 3, in which the number of second grooves and the number of planetary gears are different.

6. A flange is fixed to an input side end surface of the ring gear, The reducer according to claim 1 , wherein the flange is provided with an intake port and a discharge port connected to the flow path.

7. The reducer according to claim 6 , wherein the flange is attached to the electric motor.

8. a speed reducer that reduces the rotational drive force of the electric motor and transmits the reduced speed to the rotation drive unit; a flow path provided in a ring gear of the reduction gear unit, through which a fluid flows; the flow path is provided in a C-shape when the ring gear is viewed from the rotational axis direction of the electric motor, The flow path is a shallow first groove; At least one second groove deeper than the first groove is provided in a part of the first groove, The reduction gear unit includes a plurality of stages, the flow path is provided in the ring gear of the reduction gear unit on the most input side to which the rotational driving force of the electric motor is transmitted among the multiple stages of reduction gear units, The speed reducer is a sun gear to which the rotational driving force of the electric motor is input; a planetary gear provided between the sun gear and the ring gear and meshing with the sun gear and the ring gear, the ring gear is formed to surround the periphery of the sun gear and has internal teeth; The second groove is provided in plurality at predetermined intervals, The number of the second grooves and the number of the planetary gears are different, a flange attached to the electric motor is fixed to an input side end surface of the ring gear; The flange is provided with an intake port and a discharge port connected to the flow path.

9. 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 flow path provided in a ring gear of the reduction gear unit, through which a fluid flows; the flow path is provided in a C-shape when the ring gear is viewed from the rotational axis direction of the electric motor, The flow path is a shallow first groove; At least one second groove deeper than the first groove is provided in a part of the first groove, the ring gear is fixed to the vehicle body or the drive wheel, and the rotational drive force of the electric motor is transmitted to the drive wheel via the reducer, The flow path is connected to a fluid supply unit provided on at least one of the vehicle body and the drive wheels of the construction machine.

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