Rotary electric machine and drive device

Abstract

This rotary electric machine comprises: a shaft in which there is formed a shaft inner conduit having an opening at an end part in the direction of the axis of rotation of a rotor; a pipe that is inserted into the opening of the shaft inner conduit in a state of not contacting an inner wall of the shaft inner conduit; and a pipe-securing member that is inserted into the opening of the shaft inner conduit in a state of not contacting the inner wall of the shaft inner conduit, the pipe-securing member covering at least a portion of the pipe.

Description

Rotating electric machine and drive device

[0001] The present invention relates to a rotating electric machine and a drive device.

[0002] Rotating electric machines such as motors and generators sometimes have difficulty operating efficiently due to heat generated by their coils during operation. For this reason, technologies for cooling the coils mounted on rotating electric machines have been developed. One such technology is a rotor cooling device for a rotating electric machine disclosed in Patent Document 1. The rotor cooling device for a rotating electric machine disclosed in Patent Document 1 includes a rotor shaft and a pipe inserted into the shaft to supply a coolant to the inside of the shaft.

[0003] Japanese Patent Application Laid-Open No. 2001-197705

[0004] However, the pipe disclosed in Patent Document 1 may vibrate due to the rotation of the rotor and come into contact with the inner wall of the rotor shaft, which may impede the rotation of the rotor or prevent the coolant from being properly supplied to the inside of the rotor.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a rotating electrical machine and a drive device that are capable of suppressing vibrations in piping that supplies cooling oil to an in-shaft conduit formed in the shaft.

[0006] In order to solve the above-mentioned problems, the rotating electric machine of the present invention comprises a shaft in which an internal shaft conduit having an opening is formed at an end in the direction of the rotor's rotation axis, a pipe inserted into the opening of the internal shaft conduit without contacting the inner wall of the internal shaft conduit, and a pipe fixing member inserted into the opening of the internal shaft conduit without contacting the inner wall of the internal shaft conduit and covering at least a portion of the pipe.

[0007] In the rotating electric machine of the present invention, the pipe is press-fitted into the pipe fixing member.

[0008] In the rotating electric machine of the present invention, the piping is formed with a first protrusion that protrudes from the inside of the piping toward the outside, and the piping fixing member is a cylindrical member and is formed with a second protrusion that protrudes from the outside of the piping fixing member toward the inside and abuts the first protrusion.

[0009] In the rotating electric machine of the present invention, the pipe fixing member covers at least a portion of the pipe inside the shaft internal conduit.

[0010] The rotating electric machine of the present invention further includes a resolver that detects the rotation angle of the shaft, and a cover that is attached to the piping fixing member and covers the surface of the resolver that faces outward from the opening of the shaft internal conduit.

[0011] A drive device of the present invention includes any one of the rotating electric machines described above, and an inverter arranged adjacent to the rotating electric machine in the direction of the rotation axis.

[0012] According to the present invention, it is possible to suppress vibrations of the piping that supplies cooling oil to the shaft internal conduit formed in the shaft.

[0013] Fig. 1 is a perspective view of a drive device according to an embodiment; Fig. 2 is a cross-sectional view taken along a plane passing through a rotation axis of a motor according to an embodiment and parallel to the ZX plane; Fig. 3 is a view showing a state before a pipe according to an embodiment is press-fitted into a pipe fixing member; Fig. 4 is a view showing a state after a pipe according to an embodiment is press-fitted into a pipe fixing member; Fig. 5 is a view showing a pipe, a pipe fixing member, and a cover according to an embodiment as viewed from the -Y direction side;

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, an X-axis parallel to a rotation axis A of a motor 11 (described later), a Y-axis perpendicular to the X-axis, and a Z-axis perpendicular to the X-axis and Y-axis are used. The X-axis, Y-axis, and Z-axis form a right-handed system.

[0015] 1 is a perspective view of a drive unit according to an embodiment. The drive unit 1 is mounted on a vehicle, such as an electric vehicle, to rotate the wheels of the vehicle. As shown in FIG. 1, the drive unit 1 includes a motor 11, a cooling oil cooler 12, a cooling oil pump 13, and an inverter 14.

[0016] The motor 11 is an example of a rotating electric machine that generates power to rotate the wheels of a vehicle. The cooling oil cooler 12 is, for example, a water-cooled cooler that cools the cooling oil whose temperature has risen as a result of cooling various parts of the motor 11. The cooling oil pump 13 pumps up the cooling oil cooled by the cooling oil cooler 12 and sends it into the motor 11. The inverter 14 supplies power to the motor 11. The inverter 14 is also disposed adjacent to the motor 11 in the direction of the rotation axis A. Specifically, as shown in FIG. 1 , the inverter 14 is disposed on the −X direction side of the motor 11.

[0017] 2 is a cross-sectional view of the motor 11 taken along a plane parallel to the ZX plane and passing through the rotation axis of the motor according to the embodiment. As shown in FIG. 2, the motor 11 includes a housing 111, a bearing 112, a resolver 113, a stator 114, a shaft 115, a rotor 116, piping 117, a piping fixing member 118, and a cover 119.

[0018] The housing 111 houses bearings 112, resolver 113, stator 114, shaft 115, rotor 116, piping 117, piping fixing member 118, and cover 119. The outer rings of the two bearings 112 are fitted into the housing 111. The shaft 115 is fitted into the inner ring of the bearing 112, and the bearing 112 supports the shaft 115 in a manner that allows it to rotate around a rotation axis A. The resolver 113 is disposed at the end of the shaft 115 on the -X direction side, surrounding the shaft 115. The resolver 113 is, for example, a one-phase excitation, two-phase output variable reluctance (VR) resolver, and detects the rotation angle of the shaft 115.

[0019] The stator 114 includes a stator core 1141 and a coil 1142. The stator core 1141 is a cylindrical member into which the shaft 115 and the rotor 116 are inserted, and has a plurality of teeth formed on the inside. The coil 1142 is formed by winding copper wire around the teeth. When current is applied to the coil 1142, it generates a magnetic force that rotates the rotor 116.

[0020] The shaft 115 is a rod-shaped member that is fitted into the rotor 116 and supports the rotor 116 in a manner that allows the rotor 116 to rotate around the rotation axis A. The shaft 115 also has an internal shaft conduit 115a that has an opening at the end on the −X direction side in the direction of the rotation axis A of the rotor 116. The rotor 116 is circular and is formed by stacking plate-shaped members made of electromagnetic steel in the direction of the rotation axis A, and the shaft 115 is fitted into the rotor 116.

[0021] The pipe 117 is a cylindrical pipe that guides the cooling oil cooled by the cooling oil cooler 12 and delivered by the cooling oil pump 13 to the shaft internal conduit 115a. FIG. 3 is a diagram illustrating a state before the pipe according to the embodiment is press-fitted into the pipe fixing member. FIG. 4 is a diagram illustrating a state after the pipe according to the embodiment is press-fitted into the pipe fixing member. As shown in FIGS. 3 and 4, the pipe 117 is press-fitted into the pipe fixing member 118. FIG. 5 is a diagram illustrating the pipe, pipe fixing member, and cover according to the embodiment as viewed from the -Y direction side. By press-fitting the pipe 117 into the pipe fixing member 118, as shown in FIG. 5, the pipe 117 is attached to the pipe fixing member 118 so that the angle in the YZ plane centered on the pipe fixing member 118 is a predetermined angle.

[0022] As shown in FIG. 2 , a portion of the pipe 117 is inserted into the in-shaft conduit 115a without contacting the inner wall of the in-shaft conduit 115a. The central axis of the portion of the pipe 117 inserted into the in-shaft conduit 115a coincides with the rotation axis A. As indicated by the white arrow in FIG. 2 , the cooling oil passes through the pipe 117 and then flows into the in-shaft conduit 115a. The pipe 117 is formed with a first protrusion 117a that protrudes from the inside to the outside of the pipe 117. The first protrusion 117a is formed in an annular shape along the intersection of a plane perpendicular to the rotation axis A and the pipe 117. That is, the first protrusion 117a is formed in a flange-like shape that protrudes annularly from the outer circumferential surface of the pipe 117 in a direction perpendicular to the rotation axis A.

[0023] The piping fixing member 118 is a cylindrical member that is inserted into the opening of the shaft conduit 115a without contacting the inner wall of the shaft conduit 115a. The piping fixing member 118 has a step where the inner diameter discontinuously decreases at a position a predetermined distance from the opening of the shaft conduit 115a. That is, the inner diameter of the piping fixing member 118 at a position further away from the opening of the shaft conduit 115a than the step is smaller than the inner diameter of the portion of the piping fixing member 118 at a distance equal to or less than the predetermined distance from the opening of the shaft conduit 115a.

[0024] The piping fixing member 118 has a surface on the −X direction side that is parallel to a plane perpendicular to the rotation axis A, and this surface covers the end face of the shaft 115 on the −X direction side. The piping fixing member 118 also covers at least a portion of the piping 117. Specifically, the piping fixing member 118 covers at least a portion of the piping 117 inside the internal shaft conduit 115a. More specifically, the piping fixing member 118 covers the portion of the piping 117 that is inserted into the internal shaft conduit 115a. The piping fixing member 118 may cover the entire portion of the piping 117 that is inserted into the internal shaft conduit 115a, or may cover only a portion of that portion.

[0025] 2, the piping fixing member 118 has a second protruding portion 118a that protrudes inward from the outside of the piping fixing member 118 and abuts against the first protruding portion 117a. The second protruding portion 118a is the step described above, i.e., a step where the inner diameter discontinuously decreases at a position a predetermined distance away from the opening of the shaft internal conduit 115a.

[0026] The cover 119 is a disk-shaped member attached to a portion of the piping fixing member 118 that covers the end face of the shaft 115 on the −X direction side. The cover 119 covers the surface of the resolver 113 that faces outward from the opening of the shaft internal conduit 115a. The cover 119 is made of a metal such as iron, and prevents electrical noise generated in the inverter 14 from propagating to the resolver 113. The cover 119 is preferably made of a material that can effectively suppress noise propagating from the inverter 14 to the resolver 113 in accordance with the characteristics of the noise. The cover 119 may have any shape as long as it can separate the inverter 14 and the resolver 113 in the direction of the rotation axis A.

[0027] The motor 11 according to the embodiment has been described above. The motor 11 includes a shaft 115, a pipe 117, and a pipe fixing member 118. The shaft 115 has an internal-shaft conduit 115a with an opening at its end in the direction of the rotation axis A of the rotor 116. The pipe 117 is inserted into the opening of the internal-shaft conduit 115a without contacting the inner wall of the internal-shaft conduit 115a. The pipe fixing member 118 is inserted into the opening of the internal-shaft conduit 115a without contacting the inner wall of the internal-shaft conduit 115a, and covers at least a portion of the pipe 117. This configuration allows the motor 11 to suppress vibrations of the pipe 117 that supplies cooling oil to the internal-shaft conduit 115a and to prevent the pipe 117 from coming into contact with the inner wall of the internal-shaft conduit 115a.

[0028] Furthermore, the pipe 117 is press-fitted into the pipe fixing member 118. As a result, even if the dimensional accuracy of each part of at least one of the pipe 117 and the pipe fixing member 118 is low, the pipe 117 can be attached to the pipe fixing member 118 so that the angle in the YZ plane centered on the pipe fixing member 118 is a predetermined angle. Furthermore, because the dimensional accuracy of each part of at least one of the pipe 117 and the pipe fixing member 118 does not need to be low, the motor 11 can be manufactured at low cost.

[0029] Furthermore, the pipe 117 is formed with a first protrusion 117a that protrudes from the inside of the pipe 117 toward the outside. In this case, the pipe fixing member 118 is a cylindrical member and is formed with a second protrusion 118a that protrudes from the outside of the pipe fixing member 118 toward the inside and abuts against the first protrusion 117a. This makes it possible to easily fix the pipe 117 at a predetermined position relative to the pipe fixing member 118, even if the dimensional accuracy of each part of at least one of the pipe 117 and the pipe fixing member 118 is low. Furthermore, because the dimensional accuracy of each part of at least one of the pipe 117 and the pipe fixing member 118 is not required, the motor 11 can be manufactured at low cost.

[0030] Furthermore, the pipe fixing member 118 covers at least a portion of the pipe 117 inside the shaft internal conduit 115a, so that the motor 11 can more effectively suppress vibration of the pipe 117 than when the pipe fixing member 118 does not cover the pipe 117 inside the shaft internal conduit 115a, and can prevent the pipe 117 from coming into contact with the inner wall of the shaft internal conduit 115a.

[0031] The motor 11 also includes a resolver 113 and a cover 119. The resolver 113 detects the rotation angle of the shaft 115. The cover 119 is attached to a piping fixing member 118 and covers the surface of the resolver 113 that faces outward from the opening of the shaft internal conduit 115a. This allows the motor 11 to suppress electrical noise generated by the inverter 14 from being transmitted to the resolver 113.

[0032] The drive unit 1 also includes an inverter 14 disposed adjacent to the motor 11 in the direction of the rotation axis A. More specifically, the inverter 14, cover 119, and resolver 113 are disposed in this order from the −X direction side to the +X direction side in the direction of the rotation axis A in Fig. 2. This reduces the height of the drive unit 1, making it less likely to interfere with spaces such as the passenger compartment of the vehicle.

[0033] In the above-described embodiment, the pipe 117 includes the annular first protrusion 117a formed along the intersection of the plane perpendicular to the rotation axis A with the pipe 117, but the present invention is not limited to this. The first protrusion may have any shape that can abut against the second protrusion formed on the pipe fixing member and position the pipe relative to the pipe fixing member at a predetermined position. For example, the first protrusion may be a plurality of protrusions that protrude from the outer peripheral surface of the pipe 117 in a direction perpendicular to the rotation axis A.

[0034] Furthermore, in the above-described embodiment, the piping fixing member 118 includes the second protrusion 118a, which is a step where the inner diameter discontinuously decreases at a predetermined distance from the opening of the shaft conduit 115a. However, the present invention is not limited to this. The second protrusion may have any shape that can abut against the first protrusion formed on the piping fixing member and position the piping relative to the piping fixing member at a predetermined position. For example, the second protrusion may be a plurality of protrusions protruding from the inner circumferential surface of the piping fixing member 118 toward the rotation axis A. Alternatively, the second protrusion may be an annular member protruding from the inner circumferential surface of the piping fixing member 118 toward the rotation axis A.

[0035] In the above-described embodiment, the case where the pipe 117 is press-fitted into the pipe fixing member 118 has been described as an example, but the manner in which the pipe is connected to the pipe fixing member is not limited to this. For example, the pipe may be connected to the pipe fixing member by a thread formed on the pipe and a thread formed on the pipe fixing member.

[0036] The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. In other words, the present invention includes embodiments in which various modifications, substitutions, design changes, etc. have been made based on the spirit of the present invention, and does not exclude these embodiments.

[0037] 1... drive device, 11... motor, 12... cooling oil cooler, 13... cooling oil pump, 14... inverter, 111... housing, 112... bearing, 113... resolver, 114... stator, 115... shaft, 116... rotor, 117... piping, 118... piping fixing member, 119... cover

Claims

1. A rotating electric machine comprising: a shaft in which a shaft internal conduit having an opening is formed at an end in the direction of the rotation axis of a rotor; a pipe inserted into the opening of the shaft internal conduit without contacting the inner wall of the shaft internal conduit; and a pipe fixing member inserted into the opening of the shaft internal conduit without contacting the inner wall of the shaft internal conduit, and covering at least a portion of the pipe.

2. The rotating electric machine according to claim 1, wherein the pipe is press-fitted into the pipe fixing member.

3. A rotating electric machine as described in claim 1, wherein the piping is formed with a first protrusion that protrudes from the inside of the piping toward the outside, and the piping fixing member is a cylindrical member and is formed with a second protrusion that protrudes from the outside of the piping fixing member toward the inside and abuts against the first protrusion.

4. The rotating electric machine according to claim 1, wherein the pipe fixing member covers at least a portion of the pipe inside the shaft conduit.

5. A rotating electric machine as described in claim 1, further comprising: a resolver that detects the rotation angle of the shaft; and a cover attached to the piping fixing member and covering the surface of the resolver that faces outward from the opening of the shaft internal conduit.

6. A drive device comprising: a rotating electric machine according to any one of claims 1 to 5; and an inverter arranged adjacent to the rotating electric machine in the direction of the rotation axis.

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