Gear device

Abstract

To provide a gear device that restrains electrolytic corrosion.SOLUTION: A gear device 1 is installed in a railroad vehicle, and transmits a turning force transmitted from an electric motor, to an axle. The gear device 1 comprises a gear wheel 12, and a first insulation member 13 having insulation performance. A through hole 12a into which the axle is inserted is formed in the gear wheel 12. The gear wheel 12 rotates integrally with the axle when the turning force is transmitted from the electric motor. The first insulation member 13 is provided on a wall surface 12b of the through hole 12a of the gear wheel 12, and electrically insulates the gear wheel 12 and the axle.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to gear arrangements. [Background technology]

[0002] A railway vehicle is provided with a power conversion device that converts power supplied from a power source into power to be supplied to an electric motor, an electric motor that is driven and rotated by the power supplied from the power conversion device, and a gear device that transmits the rotational force transmitted from the electric motor to the axle. The gear device transmits the rotational force of the electric motor to the axle, enabling the railway vehicle to run.

[0003] An example of this type of gear device is disclosed in Patent Document 1. The gear device disclosed in Patent Document 1 includes a small gear connected to the output shaft of a drive source, a large gear that fits on an axle and meshes with the small gear, and a bearing that rotatably supports the axle. A larger torque is applied to the large gear than to the small gear. To prevent the axle from slipping out of the large gear, the axle is press-fitted into the large gear. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-146071 A Summary of the Invention [Problem to be solved by the invention]

[0005] In addition to the above devices, railway vehicles are provided with a grounding device that grounds the power conversion device by passing the current flowing out of the power conversion device through the axles and wheels to the rails. If the current flowing out of the power conversion device passes through the gear device to the rails without passing through the grounding device, electrical corrosion of the gear device may occur, and the gear device may be damaged.

[0006] The present disclosure has been made in consideration of the above-mentioned circumstances, and has an object to provide a gear device that suppresses electrolytic corrosion. [Means for solving the problem]

[0007] In order to achieve the above object, the gear device of the present disclosure is a gear device that is mounted on a railway vehicle and transmits rotational force transmitted from an electric motor to an axle, and includes a large gear and an insulating first insulating member. The large gear has a through hole through which the axle is inserted, and rotates integrally with the axle when rotational force is transmitted from the electric motor. The first insulating member is provided on the wall surface of the through hole of the large gear, and electrically insulates the large gear from the axle. Effect of the Invention

[0008] The gear device of the present disclosure includes a first insulating member that is formed in the large gear and is provided on the wall surface of a through hole through which the axle is inserted. The provision of the first insulating member electrically insulates the axle and the large gear, thereby preventing current flowing out of the power conversion device from passing through the gear device and suppressing electrolytic corrosion. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a top view of a truck to which a gear device according to a first embodiment is attached. [Diagram 2] 2 is a cross-sectional view of a gear device according to a first embodiment taken along line II-II in FIG. 1 . [Diagram 3] FIG. 3 is a side view of the gear device according to the first embodiment taken along line III-III in FIG. 2 . [Figure 4] 1 is a cross-sectional view of a gear according to a first embodiment; [Diagram 5] 11 is a cross-sectional view of a gear device according to a second embodiment. [Figure 6] FIG. 11 is a cross-sectional view of a gear according to a second embodiment of the present invention; [Figure 7] 11 is a cross-sectional view of a gear device according to a third embodiment. [Figure 8] FIG. 13 is a cross-sectional view of a modified example of the gear device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a gear device according to an embodiment of the present disclosure will be described in detail with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0011] (Embodiment 1) The gear device according to the first embodiment will be described by taking as an example a gear device mounted on a railway vehicle, which is one example of a vehicle. Fig. 1 shows a bogie 50 that supports the body of the railway vehicle. A gear device 1, an electric motor 51, and an axle 53 are attached to the bogie 50. In Fig. 1, the Z axis indicates the vertical direction, the X axis indicates the traveling direction of the railway vehicle, and the Y axis indicates the width direction of the railway vehicle, i.e., the extension direction of the axle 53. The X axis, Y axis, and Z axis are perpendicular to each other. The same applies to the subsequent figures.

[0012] The electric motor 51 is a power source that is driven by electric power supplied from a power conversion device (not shown) to generate a rotational force. When the electric motor 51 is driven, the shaft 51a rotates.

[0013] The joint 52 transmits the rotational force transmitted from the shaft 51a to the gear device 1 via the drive shaft 52a. In other words, the drive shaft 52a is rotated by the electric motor 51, which is a power source.

[0014] The axle 53 is attached to the bogie 50 via an axle spring (not shown). Wheels 54 are attached to both ends of the axle 53. When a rotational force is transmitted from the gear device 1 to the axle 53, the axle 53 rotates together with the wheels 54.

[0015] The gear device 1 transmits the torque transmitted from the electric motor 51 via a joint 52 to an axle 53. As shown in Fig. 2, which is a cross-sectional view taken along line II-II in Fig. 1, and Fig. 3, which is a cross-sectional view taken along line III-III in Fig. 2, the gear device 1 includes a gear 12 that rotates integrally with the axle 53 when torque is transmitted from the electric motor 51, and a first insulating member 13 that is insulating and provided on a wall surface 12b of a through hole 12a of the gear 12. In Fig. 3, the axle 53 is omitted to avoid complicating the drawing.

[0016] The gear device 1 further includes a small gear 11 attached to the drive shaft 52a and meshing with the large gear 12, a pair of bearings (not shown) that rotatably support the drive shaft 52a, a pair of bearings 17a, 17b that rotatably support the axle 53, and bearing holders 18a, 18b that respectively hold the bearings 17a, 17b.

[0017] Bearing 17a is a rolling bearing having an inner ring 21a attached to axle 53, an outer ring 22a held in bearing holder 18a, and rolling elements 23a that roll between the inner ring 21a and the outer ring 22a. Bearing 17b is a rolling bearing having an inner ring 21b attached to axle 53, an outer ring 22b held in bearing holder 18b, and rolling elements 23b that roll between the inner ring 21b and the outer ring 22b.

[0018] The gear device 1 further includes a gear box 15 that houses the above-mentioned pinion 11, gear 12, and bearings 17a, 17b, and a cover 16 that closes an opening at the vertical top of the gear box 15. The gear box 15 is filled with lubricating oil 14 that smooths the movements of the pinion 11, gear 12, and bearings 17a, 17b.

[0019] The gear device 1 further includes oil throwers 19a, 19b that prevent the lubricating oil 14 inside the gear box 15 from leaking out, and an earth ring 20 that passes the current flowing out from the power conversion device to the rail via a ground brush (not shown).

[0020] Each part of the gear device 1 will be described below. As shown in Figures 1 and 2, the pinion 11 is attached to a drive shaft 52a and rotates integrally with the drive shaft 52a. That is, when the shaft 51a of the electric motor 51 rotates, the pinion 11 rotates integrally with the drive shaft 52a which rotates in conjunction with the rotation of the shaft 51a. The pinion 11 meshes with the large gear 12 and transmits the rotational force transmitted from the shaft 51a of the electric motor 51 via the joint 52 to the large gear 12.

[0021] 2, the large gear 12 is attached to the axle 53 in a state of meshing with the pinion 11. More specifically, the large gear 12 is attached to the axle 53 by an interference fit. The large gear 12 rotates integrally with the axle 53 as the pinion 11 rotates. In the first embodiment, the large gear 12 is a gear having a larger radius and a larger number of teeth than the pinion 11.

[0022] The first insulating member 13 is provided on a wall surface 12b of a through hole 12a formed in the gear wheel 12. The first insulating member 13 electrically insulates the gear wheel 12 from an axle 53 that is inserted through the through hole 12a of the gear wheel 12.

[0023] The gear box 15 shown in Figures 2 and 3 houses the pinion 11, the gear 12, bearings 17a, 17b, and a pair of bearings (not shown) that rotatably support the drive shaft 52a. Openings for passing the axle 53 are formed on both sides of the gear box 15 that intersect with the Y axis. The opening formed on the face of the gear box 15 on the positive side of the Y axis is closed by the bearing holder 18a and the oil thrower 19a. The opening formed on the face of the gear box 15 on the negative side of the Y axis is closed by the bearing holder 18b and the oil thrower 19b. The opening at the vertical upper part of the gear box 15 is closed by the lid 16. No opening is formed at the vertical lower part of the gear box 15, and the pinion 11 and the gear 12 are inserted and removed through the opening at the vertical upper part of the gear box 15.

[0024] The bearings 17a and 17b rotatably support the axle 53. In particular, the inner ring 21a of the bearing 17a is attached to the axle 53 and rotates integrally with the axle 53. The inner ring 21a is fixed to the axle 53 to such an extent that it does not move in the Y-axis direction when the axle 53 rotates. For example, the inner ring 21a is press-fitted to the axle 53. The outer ring 22a is held by the bearing holder 18a. In particular, the outer ring 22a is fixed to the bearing holder 18a. For example, the outer ring 22a is press-fitted to the bearing holder 18a. The rolling element 23a is sandwiched between the inner ring 21a and the outer ring 22a and rolls with the rotation of the inner ring 21a which rotates integrally with the axle 53.

[0025] The inner ring 21b of the bearing 17b is attached to the axle 53 and rotates integrally with the axle 53. More specifically, the inner ring 21b is firmly fixed to the axle 53 so as not to move in the Y-axis direction when the axle 53 rotates. For example, the inner ring 21b is press-fitted into the axle 53. The outer ring 22b is held by the bearing holder 18b. More specifically, the outer ring 22b is fixed to the bearing holder 18b. For example, the outer ring 22b is press-fitted into the bearing holder 18b. The rolling element 23b is sandwiched between the inner ring 21b and the outer ring 22b and rolls in accordance with the rotation of the inner ring 21b which rotates integrally with the axle 53.

[0026] Bearing holder 18a holds bearing 17a and is attached to gear box 15 in a state where it closes an opening formed in the face of gear box 15 on the Y-axis positive side. Bearing holder 18b holds bearing 17b and is attached to gear box 15 in a state where it closes an opening formed in the face of gear box 15 on the Y-axis negative side.

[0027] The oil throwers 19a, 19b are attached to the axle 53 at positions sandwiching the bearings 17a, 17b. More specifically, the oil throwers 19a, 19b are fixed to the axle 53. For example, the oil throwers 19a, 19b are press-fitted onto the axle 53. The outer peripheral surfaces of the oil throwers 19a, 19b are formed with irregularities. The irregularities formed on the outer peripheral surface of the oil thrower 19a form a labyrinth flow path between the oil thrower 19a and the bearing holder 18a. The irregularities formed on the outer peripheral surface of the oil thrower 19b form a labyrinth flow path between the oil thrower 19b and the bearing holder 18b. These labyrinth flow paths prevent the lubricating oil 14 sealed inside the gear box 15 from leaking out of the gear box 15.

[0028] Earth ring 20 is made of a conductive material and passes the current flowing out from the power conversion device to the rail via a ground brush (not shown). Earth ring 20 is firmly fixed to axle 53 so that it does not move in the Y-axis direction when axle 53 rotates. For example, earth ring 20 is press-fitted onto axle 53.

[0029] The details of the structure for suppressing electrolytic corrosion of the gear device 1 having the above configuration will be described below. As shown in FIG. 4, the large gear 12 is formed with a through hole 12a through which the axle 53 is inserted. A first insulating member 13 having insulating properties is provided on a wall surface 12b of the through hole 12a. In the first embodiment, the through hole 12a is a through hole having a circular cross section perpendicular to the through direction. The diameter of the through hole 12a is constant. The first insulating member 13 is, for example, a ceramic coating layer formed on the wall surface 12b of the through hole 12a. In detail, the first insulating member 13 is formed by spraying a ceramic member such as alumina onto the entire surface of the wall surface 12b.

[0030] The first insulating member 13, which is an insulating ceramic coating layer, is provided on the wall surface 12b of the through hole 12a, thereby insulating the large gear 12 from the axle 53 inserted into the through hole 12a. As a result, the current flowing out of the power conversion device is prevented from passing through the gear device 1, the axle 53, and the earth ring 20 to the rail.

[0031] As described above, the gear device 1 according to the first embodiment includes the first insulating member 13 that electrically insulates the large gear 12 and the axle 53. This configuration prevents the current flowing out of the power conversion device from passing through the gear device 1 to the axle 53 and then from the earth ring 20 to the rail. As a result, electrolytic corrosion of the gear device 1 is suppressed.

[0032] (Embodiment 2) The configuration of the gear device is arbitrary as long as it can electrically insulate the large gear and the axle. A gear device having a large gear with a different shape from that of the first embodiment will be described in the second embodiment, focusing on the differences from the first embodiment.

[0033] 5 is similar in configuration to the gear device 1 according to embodiment 1. The shape of the gear wheel 12 included in the gear device 2 is different from that of the gear device 1 included in the gear device 1.

[0034] As shown in Fig. 6, the through hole 12a of the gear 12 has a tapered shape in which the diameter at one end in the through-hole direction, i.e., in the Y-axis direction, is larger than the diameter at the other end in the Y-axis direction. In the second embodiment, the through hole 12a is a through hole having a circular cross section perpendicular to the through-hole direction. The diameter of the through hole 12a decreases toward the positive Y-axis direction. In detail, the diameter R1 of the end of the through hole 12a on the negative Y-axis direction side is larger than the diameter R2 of the end of the through hole 12a on the positive Y-axis direction side.

[0035] The portion of the axle 53 that fits into the large gear 12 has the same tapered shape as the through hole 12a. The axle 53 is inserted into the through hole 12a of the large gear 12 in a direction in which the diameter of the through hole 12a narrows, in other words, in the positive direction of the Y axis, and fits into the large gear 12.

[0036] Similar to the first embodiment, a first insulating member 13 is provided on wall surface 12b of through hole 12a having a tapered shape. The surface contact ratio of the mating surface between first insulating member 13, which is a ceramic coating layer, and axle 53 is lower than the surface contact ratio of the mating surface between gear wheel 12 and axle 53, but by making through hole 12a tapered, the decrease in the surface contact ratio and the occurrence of tearing off of first insulating member 13 when axle 53 is mated with gear wheel 12 are suppressed.

[0037] The taper ratio may be a value within a range that prevents the axle 53 from slipping off the gear 12, and also prevents a decrease in the surface contact ratio and the occurrence of tearing off of the first insulating member 13 when fitting the axle 53 to the gear 12. For example, the taper ratio may be a value within a range from 1 / 50 to 1 / 200.

[0038] As described above, the through hole 12a of the gear 12 provided in the gear device 2 of embodiment 2 has a tapered shape, which suppresses a decrease in the surface contact ratio and the occurrence of tearing of the first insulating member 13 when the axle 53 is fitted to the gear 12.

[0039] (Embodiment 3) The configuration of the gear device is arbitrary as long as it can electrically insulate the large gear and the axle. A gear device having a different configuration from those in the first and second embodiments will be described in the third embodiment, focusing on the differences from the first embodiment.

[0040] The gear device 3 of embodiment 3 shown in Figure 7 has, in addition to the configuration of the gear device 1 shown in embodiment 1, a plurality of insulating second insulating members 24a, 24b provided between each of the bearings 17a, 17b and the large gear 12.

[0041] The second insulating member 24a is a ceramic coating layer formed around the through hole 12a on the surface facing the positive direction of the Y axis of the gear 12. In detail, the second insulating member 24a is formed by spraying ceramic around the through hole 12a on the surface facing the positive direction of the Y axis of the gear 12. The second insulating member 24a abuts against the surface facing the positive direction of the Y axis of the gear 12 and the inner ring 21a of the bearing 17a.

[0042] Similarly, the second insulating member 24b is a ceramic coating layer formed around the through hole 12a on the surface facing the negative direction of the Y axis of the gear 12. In detail, the second insulating member 24b is formed by spraying ceramic around the through hole 12a on the surface facing the negative direction of the Y axis of the gear 12. The second insulating member 24b abuts against the surface facing the negative direction of the Y axis of the gear 12 and the inner ring 21b of the bearing 17b.

[0043] The second insulating members 24a, 24b, which are insulating ceramic coating layers, are provided around the through hole 12a of the gear wheel 12, thereby insulating the gear wheel 12 from the bearings 17a, 17b. As a result, the current flowing out of the power conversion device is prevented from passing through the gear device 3, the bearings 17a, 17b and the axle 53, and from the earth ring 20 to the rail.

[0044] As described above, the gear device 3 according to the third embodiment includes second insulating members 24a, 24b that electrically insulate the large gear 12 from the bearings 17a, 17b. This configuration prevents the current flowing out of the power conversion device from passing through the gear device 3, through the bearings 17a, 17b and the axle 53, and from the earth ring 20 to the rail. As a result, electrolytic corrosion of the gear device 3 is suppressed.

[0045] The present disclosure is not limited to the above-described embodiments. The above-described embodiments can be combined in any manner. As an example, the gear device 4 shown in FIG. 8 includes second insulating members 24a and 24b in addition to the configuration of the gear device 2 according to the second embodiment.

[0046] The bearings 17a and 17b are not limited to the rolling bearings shown in the above embodiment, but may be plain bearings.

[0047] The gear device 1-4 is not limited to being mounted on a railway vehicle, but may be mounted on any moving object such as an automobile or a bus.

[0048] The surface of the first insulating member 13 facing the axle 53 may be polished. By polishing the surface of the first insulating member 13 facing the axle 53, the surface contact ratio of the fitting surfaces of the first insulating member 13 and the axle 53 is improved.

[0049] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) A gear device that is mounted on a railway vehicle and transmits a rotational force transmitted from an electric motor to an axle, a large gear having a through hole through which the axle is inserted and which rotates together with the axle when torque is transmitted from the electric motor; a first insulating member provided on a wall surface of the through hole of the gear wheel and electrically insulating the gear wheel and the axle; A gear device comprising: (Appendix 2) The through hole has a tapered shape in which a diameter of one end in a through-hole direction is larger than a diameter of the other end in the through-hole direction. 2. A gear arrangement as described in claim 1. (Appendix 3) The first insulating member is a ceramic coating layer formed on the wall surface of the through hole. 3. A gear arrangement according to claim 1 or 2. (Appendix 4) a pair of bearings that rotatably support the axle by sandwiching the large gear in a penetrating direction of the through hole; A plurality of second insulating members provided between the bearing and the gear wheel; 4. The gear device of claim 1, further comprising: (Appendix 5) The second insulating member is a ceramic coating layer provided on a surface of the gear wheel facing the bearing. 5. The gearing of claim 4. [Explanation of symbols]

[0050] 1,2,3,4 gear device, 11 pinion, 12 gear, 12a through hole, 12b wall surface, 13 first insulating member, 14 lubricating oil, 15 gear box, 16 cover, 17a,17b bearing, 18a,18b bearing holder, 19a,19b oil thrower, 20 earth ring, 21a,21b inner ring, 22a,22b outer ring, 23a,23b rolling element, 24a,24b second insulating member, 50 bogie, 51 electric motor, 51a shaft, 52 coupling, 52a drive shaft, 53 axle, 54 wheel, R1,R2 diameter.

Claims

1. A gear device that is mounted on a railway vehicle and transmits a rotational force transmitted from an electric motor to an axle, a large gear having a through hole through which the axle is inserted and which rotates together with the axle when torque is transmitted from the electric motor; a first insulating member provided on a wall surface of the through hole of the gear wheel to electrically insulate the gear wheel from the axle; A gear device comprising:

2. The through hole has a tapered shape in which a diameter of one end in a through-hole direction is larger than a diameter of the other end in the through-hole direction.

2. The gear arrangement of claim 1.

3. The first insulating member is a ceramic coating layer formed on the wall surface of the through hole. A gear device according to claim 1 or 2.

4. a pair of bearings that rotatably support the axle by sandwiching the large gear in a penetrating direction of the through hole; a plurality of second insulating members provided between the bearing and the gear wheel; The gear arrangement of claim 1 or 2, further comprising:

5. a pair of bearings that rotatably support the axle by sandwiching the large gear in a penetrating direction of the through hole; a plurality of second insulating members provided between the bearing and the gear wheel; The gear arrangement of claim 3 further comprising:

6. the second insulating member is a ceramic coating layer provided on a surface of the gear wheel facing the bearing; 5. The gear arrangement of claim 4.

7. the second insulating member is a ceramic coating layer provided on a surface of the gear wheel facing the bearing; 6. The gear arrangement of claim 5.

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