Reduction gear

Abstract

This reduction gear (1) has a sun gear (21), a plurality of planetary gears (22), a carrier (23), a plurality of shafts (11), a sun gear transmission path (13), and a carrier transmission path (14). The plurality of planetary gears (22) are disposed around the sun gear (21) and mesh with the sun gear (21). The carrier (23) rotatably supports the plurality of planetary gears (22). A ring gear (24) is disposed around the plurality of planetary gears (22) and meshes with the plurality of planetary gears (22). The output of the electric motor (2) can be input to each of the plurality of shafts (11). The sun gear transmission path (13) transmits power input to the shaft (11) to the sun gear (21) to rotate the sun gear (21). The carrier transmission path (14) transmits the power input to the shaft (11) to the carrier (23) to rotate the carrier (23).

Description

reducer

[0001] The present invention relates to a reducer.

[0002] Conventionally, work machines have used reducers provided with a planetary gear mechanism for travel (see, for example, Patent Document 1). The planetary gear mechanism includes a sun gear, a plurality of planetary gears arranged around the sun gear, and a ring gear arranged around the plurality of planetary gears, and the plurality of planetary gears are supported by a planetary carrier.

[0003] The reducer disclosed in Patent Document 1 uses a hydraulic motor as a drive source, and travel is achieved by reducing the input from the hydraulic motor and outputting it.

[0004] Japanese Patent Application Laid-Open No. 2002-130394

[0005] However, when an electric motor is used as a drive source in a conventional reducer to increase speed, there are cases where the output torque is insufficient.

[0006] An object of the present disclosure is to provide a reducer that can improve output torque.

[0007] The reducer according to the first disclosure has a sun gear, a plurality of planetary gears, a carrier, a plurality of input shafts, a sun gear transmission path, and a carrier transmission path. The plurality of planetary gears are arranged around the sun gear and mesh with the sun gear. The carrier rotatably supports the plurality of planetary gears. The ring gear is arranged around the plurality of planetary gears and meshes with the plurality of planetary gears. The plurality of input shafts can each receive motor output. The sun gear transmission path transmits power input to the input shaft to the sun gear to rotate the sun gear. The carrier transmission path transmits power input to the input shaft to the carrier to rotate the carrier.

[0008] The reducer according to the second disclosure includes a sun gear, a plurality of planetary gears, a carrier, an input shaft, and a carrier transmission path. The plurality of planetary gears are arranged around the sun gear and mesh with the sun gear. The ring gear is arranged around the plurality of planetary gears and meshes with the plurality of planetary gears. The input shaft can receive motor output, and the sun gear is fixed to the input shaft. The carrier transmission path transmits power input to the input shaft to the carrier, causing the carrier to rotate. (Effects of the Invention)

[0009] According to the present disclosure, it is possible to provide a reducer capable of improving output torque.

[0010] FIG. 4B is a perspective view showing the overall configuration of a reducer of embodiment 1 according to the present disclosure. FIG. 4C is a perspective view showing the overall configuration of a reducer of embodiment 1 according to the present disclosure. FIG. 4D is an explanatory diagram of a gear train of a reducer of embodiment 1 according to the present disclosure. FIG. 4E is a diagram of the reducer of embodiment 1 according to the present disclosure as viewed from a first direction side. FIG. 4F is a diagram of the reducer of embodiment 1 according to the present disclosure as viewed from a second direction side. FIG. 4G is a side view of the reducer of embodiment 1 according to the present disclosure as viewed from direction B in FIG. 4A. FIG. 4H is a cross-sectional view taken along the arrows CC' in FIG. 4A. FIG. 4I is an explanatory diagram of a gear train of a reducer of embodiment 2 according to the present disclosure.

[0011] A reducer according to an embodiment of the present disclosure will be described below with reference to the drawings. The reducer according to the present disclosure can be used, for example, in a travel device of a work machine or a vehicle. Examples of work machines include bulldozers, wheel loaders, and excavators. The reducer according to the present disclosure is not limited to travel devices, but may also be used in transmissions, or, if the work machine has a rotating body, in swing machinery that rotates the rotating body. The reducer according to the present disclosure may also be used for swinging at a joint of the work equipment of the work machine. Furthermore, the target to which the reducer according to the present disclosure is applied is not limited to work machines or vehicles, but may also be used, for example, in robots, etc., in a configuration in which the power of an electric motor is reduced and output.

[0012] (First embodiment) (Outline of reducer 1) Fig. 1 is a perspective view showing the overall configuration of a reducer 1 according to a first embodiment of the present disclosure. Fig. 2 is a perspective view showing the overall configuration of the reducer 1 as viewed from the opposite side to that of Fig. 1. Fig. 3 is an explanatory diagram of a gear train of the reducer 1 according to the first embodiment.

[0013] As shown in FIGS. 1 to 3, the reducer 1 of this embodiment has a plurality of shafts 11, a planetary gear mechanism 12, a sun gear transmission path 13, and a carrier transmission path 14. As shown in FIG. 1, the plurality of shafts 11 are arranged parallel to one another. As shown in FIG. 3, the output of an electric motor 2 (an example of a motor) can be input to each of the shafts 11. An output shaft of the electric motor 2 can be connected to each of the shafts 11. As shown in FIG. 1, the reducer 1 of this embodiment 1 has three shafts 11. Note that only two shafts 11 are shown in the explanatory diagram of the gear train in FIG. 3. In this embodiment 1, the shafts 11 correspond to an example of an input shaft.

[0014] 3, a driving force is transmitted from a sun gear shaft 43 (described later) to the planetary gear mechanism 12, and a reduced driving force is output from the planetary gear mechanism 12. Within the input axial direction A along the shaft 11, the direction in which the output of the electric motor 2 is input to the shaft 11 is indicated as a first direction A1, and the direction opposite to the first direction A1 is indicated as a second direction A2. The planetary gear mechanism 12 is disposed closer to the first direction A1 than the shaft 11.

[0015] As shown in Fig. 3, the sun gear transmission path 13 transmits the power input to the shaft 11 to the sun gear 21 of the planetary gear mechanism 12 to rotate the sun gear 21 (see the dotted line in Fig. 3). The carrier transmission path 14 transmits the power input to the shaft 11 to the carrier 23 of the planetary gear mechanism 12 to rotate the carrier 23 (see the dashed line in Fig. 3).

[0016] (Planetary Gear Mechanism 12) As shown in Fig. 2, the planetary gear mechanism 12 has a sun gear 21, a plurality of planetary gears 22, a carrier 23, and a ring gear 24. Fig. 4A is a view of the reducer 1 viewed from the first direction A1. Fig. 4B is a view of the reducer 1 viewed from the second direction A2. As shown in Figs. 2 and 4A, the sun gear 21 is fixed to a sun gear shaft 43. The sun gear shaft 43 is disposed parallel to the shaft 11. In Fig. 3, the number of teeth of the sun gear 21 is indicated as Z1.

[0017] As shown in Figures 2 and 4A, the multiple planetary gears 22 are arranged around the sun gear 21. Each planetary gear 22 meshes with the sun gear 21. When the sun gear 21 rotates, the planetary gears 22 rotate on their axes. In this embodiment, the planetary gear mechanism 12 has three planetary gears 22. In Figure 3, the number of teeth of the planetary gear 22 is indicated as Z2. Note that only two planetary gears 22 are shown in the explanatory diagram of the gear train in Figure 3.

[0018] The carrier 23 rotatably supports the plurality of planetary gears 22. Fig. 5 is a side view of the reducer 1 as seen in the direction of arrow B in Fig. 4A. Fig. 6 is a cross-sectional view taken along the line CC' in Fig. 4. As shown in Figs. 5 and 6, the carrier 23 is disposed around the sun gear shaft 43 so as to be rotatable relative to the sun gear shaft 43. The carrier 23 has a planetary gear support portion 31, a gear arrangement portion 32, and a connection portion 33.

[0019] As shown in FIG. 6 , the planetary gear support portion 31 is, for example, cylindrical. The planetary gear support portion 31 is arranged around the sun gear shaft 43, with the sun gear shaft 43 as its center. As shown in FIGS. 1 and 2 , a plurality of through holes 31 a are formed in the planetary gear support portion 31, and planetary gear shafts 34 that support the planetary gears 22 are arranged in the through holes 31 a. The planetary gear shafts 34 are arranged along the input axial direction A. The ends of the planetary gear shafts 34 on the first direction A1 side and the second direction A2 side are fixed to edges of the through holes 31 a in the planetary gear support portion 31. The planetary gears 22 are arranged inside the through holes 31 a and are rotatably attached to the planetary gear shafts 34.

[0020] As shown in Fig. 6, the gear arrangement portion 32 is cylindrical. The gear arrangement portion 32 is arranged around the sun gear shaft 43 with the sun gear shaft 43 as its center. The gear arrangement portion 32 is arranged on the second direction A2 side of the planetary gear support portion 31. The gear arrangement portion 32 has a smaller diameter than the planetary gear support portion 31. A fourth drive gear 52, which will be described later, is fixed to the gear arrangement portion 32.

[0021] 5 and 6 , the connecting portion 33 connects the planetary gear support portion 31 and the gear arrangement portion 32. The connecting portion 33 is formed from the end of the planetary gear support portion 31 on the second direction A2 side toward the sun gear shaft 43, and is connected to the end of the gear arrangement portion 32 on the first direction A1 side. When the carrier 23 configured as described above rotates, the multiple planetary gears 22 revolve around the sun gear 21.

[0022] The ring gear 24 is disposed so as to surround the periphery of the plurality of planetary gears 22. The ring gear 24 has teeth that protrude inward and mesh with each of the planetary gears 22. As shown in Fig. 3, power is output from the ring gear 24. The rotation of the ring gear 24 becomes the output of the reducer 1.

[0023] (Sun Gear Transmission Path 13) As shown in FIG. 3 , the sun gear transmission path 13 transmits power input to the shaft 11 to rotate the sun gear 21. The sun gear transmission path 13 includes a first drive gear 41, a second drive gear 42, and a sun gear shaft 43. The first drive gears 41 are fixed to the respective shafts 11. The first drive gears 41 rotate with the rotation of the shafts 11. As shown in FIGS. 1 and 4B , the reducer 1 of this embodiment includes three shafts 11, and therefore three first drive gears 41. As shown in FIG. 4B , the shafts 11 and the first drive gears 41 are arranged on the same circumference centered on the sun gear shaft 43. As shown in FIG. 5 , the first drive gear 41 is arranged on the second direction A2 side of the planetary gear mechanism 12. In FIG. 3 , the number of teeth of the first drive gear 41 is indicated as Z6. In the explanatory diagram of the gear train in FIG. 3, only two first drive gears 41 are shown.

[0024] The second drive gear 42 is disposed inside the plurality of first drive gears 41. The second drive gear 42 meshes with each of the first drive gears 41. The second drive gear 42 is fixed to the sun gear shaft 43. The second drive gear 42 is disposed on the second direction A2 side of the planetary gear mechanism 12. In FIG. 3, the number of teeth of the second drive gear 42 is indicated as Z4.

[0025] The second drive gear 42 and the sun gear 21 are fixed to the sun gear shaft 43. The sun gear shaft 43 is disposed along the input axial direction A. The sun gear shaft 43 is disposed at the center of the multiple shafts 11.

[0026] In the first embodiment, the first drive gear 41 corresponds to an example of a first sun gear drive gear, and the second drive gear 42 corresponds to an example of a second sun gear drive gear.

[0027] (Carrier Transmission Path 14) The carrier transmission path 14 transmits the power input to the shaft 11 to rotate the carrier 23.

[0028] As shown in FIG. 3 , the carrier transmission path 14 includes a plurality of third drive gears 51 and a fourth drive gear 52. As shown in FIG. 5 , the third drive gears 51 are fixed to the respective shafts 11. The plurality of third drive gears 51 are arranged on the first direction A1 side of the first drive gear 41. As shown in FIG. 4A , the plurality of third drive gears 51 are arranged on the same circumference centered on the sun gear shaft 43. The plurality of third drive gears 51 are arranged outside the gear arrangement portion 32 of the carrier 23 so as to surround the gear arrangement portion 32. As shown in FIGS. 2 and 4A , the reducer 1 of the first embodiment is provided with three third drive gears 51. In FIG. 3 , the number of teeth of the third drive gear 51 is indicated as Z7. Note that only two third drive gears 51 are shown in the explanatory diagram of the gear train in FIG. 3 .

[0029] As shown in Figures 5 and 6, the fourth drive gear 52 is fixed to the gear arrangement portion 32 of the carrier 23. The fourth drive gear 52 is arranged on the outer periphery of the gear arrangement portion 32. The fourth drive gear 52 is arranged inside the plurality of third drive gears 51. The fourth drive gear 52 meshes with each of the third drive gears 51. In Figure 3, the number of teeth of the fourth drive gear 52 is indicated as Z5.

[0030] In the first embodiment, the third drive gear 51 corresponds to an example of a first carrier drive gear, and the fourth drive gear 52 corresponds to an example of a second carrier drive gear.

[0031] (Power Transmission) The following describes the power transmission of the reducer 1 of this embodiment. Note that power from the electric motor does not need to be input to all of the multiple shafts 11, and power from the electric motor may be input to only some of the shafts 11.

[0032] The transmission of power in the sun gear transmission path 13 will now be described. As shown in Fig. 3, when the power of the electric motor 2 is input to the shaft 11 and the shaft 11 rotates, the first drive gear 41 rotates. The rotation of the first drive gear 41 rotates the second drive gear 42 meshing with the first drive gear 41, and the sun gear shaft 43 rotates. The rotation of the sun gear shaft 43 rotates the sun gear 21 fixed to the sun gear shaft 43. The rotation of the sun gear 21 causes the planetary gear 22 to rotate about the planetary gear shaft 34.

[0033] Next, the transmission of power in the carrier transmission path 14 will be described. When the shaft 11 is rotated by inputting the power of the electric motor 2 to the shaft 11, the third drive gear 51 rotates. The rotation of the third drive gear 51 rotates the fourth drive gear 52 meshing with the third drive gear 51. The rotation of the fourth drive gear 52 rotates the carrier 23. The rotation of the carrier 23 causes the multiple planetary gears 22 to revolve around the sun gear 21.

[0034] The difference between the rotation of the planetary gear 22 via the sun gear transmission path 13 and the revolution of the planetary gear 22 via the carrier transmission path 14 is transmitted to the ring gear 24, causing the ring gear 24 to rotate, and the rotation of the ring gear 24 is output to the outside.

[0035] In the reducer 1 of this embodiment, the rotation of the planetary gear 22 can be controlled by adjusting the number of teeth Z6 of the first drive gear 41, the number of teeth Z4 of the second drive gear 42, the number of teeth Z1 of the sun gear 21, and the number of teeth Z2 of the planetary gear 22.

[0036] Furthermore, in the reducer 1 of this embodiment, by adjusting the number of teeth Z7 of the third drive gear 51 and the number of teeth Z5 of the fourth drive gear 52, the rotation of the carrier 23 can be controlled, and thereby the revolution of the planetary gear 22 can be controlled.

[0037] In this way, in the reducer 1 of this embodiment, the rotation and revolution of the planetary gear 22 can be controlled independently.

[0038] (Reduction Ratio) In the reducer 1 of this embodiment, the reduction ratio I between the input shaft and the output shaft can be expressed as I = {I1 x I2 x (I3 - 1)} / (I1 x I3 - I2), I1 = Z4 / Z6, I2 = Z5 / Z7, and I3 = 1 + (Z3 / Z1). It is preferable to set the reduction ratio to 200 or more. As an example, if Z1 = 26, Z2 = 25, Z3 = 76, Z4 = 26, Z5 = 42, Z6 = 29, and Z7 = 12, the reduction ratio I = 532.

[0039] 3, the reducer 1 of this embodiment includes a plurality of shafts 11 to which the output of the electric motor 2 can be input, a sun gear transmission path 13 that transmits the power input to the shafts 11 to the sun gear 21 to rotate the sun gear 21, and a carrier transmission path 14 that transmits the power input to the shafts 11 to the carrier 23 to rotate the carrier 23. Because the output of the electric motor 2 can be input to each of the plurality of shafts 11 in this way, by increasing the number of electric motors 2, the torque input to the reducer 1 can be increased, and the output torque can be improved.

[0040] (Embodiment 2) Next, a reducer 101 of embodiment 2 will be described. The reducer 101 of embodiment 2 differs from the reducer 1 of embodiment 1 in the shaft to which power from the electric motor 2 is input. In the reducer 1 of embodiment 1, power from the electric motor 2 is input to the shaft 11, but in the reducer 101 of embodiment 2, power from the electric motor 2 is input to the sun gear shaft 43. In embodiment 2, components having the same functions as in embodiment 1 are assigned the same reference numerals as in embodiment 1, and descriptions thereof will be omitted.

[0041] 7 is an explanatory diagram of the gear train of the reducer 101 of the second embodiment. The reducer 101 of the second embodiment has a planetary gear mechanism 12, a sun gear shaft 43, and a carrier transmission path 114. Power from the electric motor 2 is input to the sun gear shaft 43. This causes the sun gear shaft 43 to rotate. The sun gear 21 is fixed to the sun gear shaft 43 and therefore rotates together with the sun gear shaft 43. The rotation of the sun gear 21 causes the planetary gear 22 to rotate on its axis. In the second embodiment, the sun gear shaft 43 corresponds to the sun gear transmission path (see the dotted line in FIG. 7).

[0042] The carrier transmission path 114 transmits the power input to the sun gear shaft 43 to rotate the carrier 23 (see the dashed line in FIG. 7 ). The carrier transmission path 114 has the second drive gear 42, the first drive gear 41, the shaft 11, the third drive gear 51, and the fourth drive gear 52.

[0043] When the sun gear shaft 43 rotates due to the output of the electric motor 2, the second drive gear 42 fixed to the sun gear shaft 43 also rotates. The rotation of the second drive gear 42 rotates the multiple first drive gears 41 meshing with the second drive gear 42. The rotation of the multiple first drive gears 41 rotates the shaft 11 to which each first drive gear 41 is fixed, and also rotates the third drive gear 51 fixed to the shaft 11. The rotation of the multiple third drive gears 51 rotates the fourth drive gear 52 meshing with the multiple third drive gears 51. Because the fourth drive gear 52 is fixed to the carrier 23, the rotation of the fourth drive gear 52 rotates the carrier 23. The rotation of the carrier 23 causes the planetary gear 22 to revolve around the sun gear 21.

[0044] In this embodiment 2, the sun gear shaft 43 corresponds to an example of an input shaft, the second drive gear 42 corresponds to an example of a third carrier drive gear, the first drive gear 41 corresponds to a fourth carrier drive gear, the third drive gear 51 corresponds to an example of a fifth carrier drive gear, and the fourth drive gear 52 corresponds to an example of a sixth carrier drive gear.

[0045] In the reducer 101 of this embodiment, the rotation of the planetary gears 22 can be controlled by adjusting the number of teeth Z1 of the sun gear 21 and the number of teeth Z2 of the planetary gears 22.

[0046] Furthermore, in the reducer 101 of this embodiment, by adjusting the number of teeth Z4 of the second drive gear 42, the number of teeth Z6 of the first drive gear 41, the number of teeth Z7 of the third drive gear 51, and the number of teeth Z5 of the fourth drive gear 52, it is possible to control the rotation of the carrier 23 and thereby control the revolution of the planetary gear 22.

[0047] In this way, in the reducer 101 of this embodiment, as in the reducer 1 of the first embodiment, the rotation and revolution of the planetary gear 22 can be controlled independently.

[0048] In the reducer 101 of this embodiment, the reduction ratio I between the input shaft and the output shaft can be expressed as I={I2×(I3−1)} / (I1×I3−I2), I1=Z4 / Z6, I2=Z5 / Z7, and I3=1+(Z3 / Z1). If Z1=26, Z2=25, Z3=76, Z4=26, Z5=42, Z6=29, and Z7=12, the reduction ratio I=593, which is higher than that of the first embodiment, and enables the output torque to be improved.

[0049] (Features, etc.) The reducer 101 of the second embodiment is capable of receiving the output of the electric motor 2 and includes a sun gear shaft 43 to which the sun gear 21 is fixed, and a carrier transmission path 114 that transmits the power input to the sun gear shaft 43 to the carrier 23 to rotate the carrier 23. By inputting the output of the electric motor 2 to the sun gear shaft 43, a high reduction ratio can be obtained, and the output torque can be improved. Furthermore, the reducer 101 of the second embodiment can obtain high output torque even when power is input from the electric motor 2 at a single point.

[0050] While one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. In particular, the multiple embodiments and modifications described in this specification can be combined as desired as necessary.

[0051] (A) In the above-described first and second embodiments, as shown in FIGS. 3 and 7, three rows of gears are arranged along the input shaft direction A, but this is not limited to three rows and may be four or more rows.

[0052] (B) In the reducers 1 and 101 of the above-mentioned embodiments 1 and 2, three shafts 11 are provided, and three first drive gears 41 and three third drive gears 51 are also provided on the shafts 11, but this is not limited to three and may be two or four or more.

[0053] (C) In the reducers 1 and 101 of the first and second embodiments, three planetary gears 22 are provided, but the number is not limited to three and may be two or four or more. Furthermore, the number of planetary gears 22 may be different from the number of shafts 11.

[0054] (D) In ​​the first embodiment, the shaft 11 is made of a single member as shown in Fig. 6, but may be made of multiple connected members. In the second embodiment, the sun gear shaft 43 is made of a single member as shown in Fig. 6, but may be made of multiple connected members.

[0055] (E) In the above embodiment, an electric motor 2 is used as an example of a motor, but this is not limiting. For example, a hydraulic motor may also be used.

[0056] The reducer of the present disclosure has the effect of being able to improve output torque, and is useful as a travel device, a transmission, etc. for a work machine.

[0057] DESCRIPTION OF SYMBOLS 1: Reducer 2: Electric motor (motor) 11: Shaft (input shaft) 12: Planetary gear mechanism 13: Sun gear transmission path 14: Carrier transmission path 21: Sun gear 22: Planetary gear 23: Carrier 24: Ring gear 31: Planetary gear support portion 31a: Through hole 32: Gear arrangement portion 33: Connection portion 34: Planetary gear shaft 41: First drive gear (first sun gear drive gear, fourth carrier drive gear) 42: Second drive gear (second sun gear drive gear, third carrier drive gear) 43: Sun gear shaft (input shaft) 51: Third drive gear (first carrier drive gear, fifth carrier drive gear) 52: Fourth drive gear (second carrier drive gear, sixth carrier drive gear) 101: Reducer 114: Carrier transmission path

Claims

1. A reducer comprising: a sun gear; a plurality of planetary gears arranged around the sun gear and meshing with the sun gear; a carrier rotatably supporting the plurality of planetary gears; a ring gear arranged around the plurality of planetary gears and meshing with the plurality of planetary gears; a plurality of input shafts, each of which can receive motor output; a sun gear transmission path that transmits power input to the input shafts to the sun gear to rotate the sun gear; and a carrier transmission path that transmits power input to the input shafts to the carrier to rotate the carrier.

2. A reducer comprising: a sun gear; a plurality of planetary gears arranged around the sun gear and meshing with the sun gear; a carrier rotatably supporting the plurality of planetary gears; a ring gear arranged around the plurality of planetary gears and meshing with the plurality of planetary gears; an input shaft to which the output of a motor can be input and to which the sun gear is fixed; and a carrier transmission path that transmits the power input to the input shaft to the carrier to rotate the carrier.

3. A reducer as claimed in claim 1 or 2, having a reduction ratio of 200 or more.

4. The reducer according to claim 1 or 2, wherein power is output from the ring gear.

5. The reducer as described in claim 1, wherein the sun gear transmission path includes a first sun gear driving gear fixed to each of the multiple input shafts, and a second sun gear driving gear arranged inside the multiple first sun gear driving gears, meshing with the multiple first sun gear driving gears, and fixed to the sun gear shaft to which the sun gear is fixed, and the carrier transmission path includes a first carrier driving gear fixed to each of the input shafts, and a second carrier driving gear meshing with the multiple first carrier driving gears and fixed to the carrier.

6. The reducer of claim 2, wherein the carrier transmission path comprises: a third carrier driving gear fixed to the input shaft; a plurality of fourth carrier driving gears arranged around the third carrier driving gear and meshing with the third carrier driving gear; a fifth carrier driving gear arranged coaxially with each of the plurality of fourth carrier driving gears and rotating together with the fourth carrier driving gear; and a sixth carrier driving gear meshing with the plurality of fifth carrier driving gears and fixed to the carrier.

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