Rotary electric machine

Abstract

To provide a rotary electric machine capable of more efficiently delivering a cooling oil to cooling oil paths that penetrate a rotor.SOLUTION: A rotary electric machine comprises: a rotor in which a plurality of cooling oil paths formed while penetrating in an axial direction are disposed in a circumferential direction; a shaft that penetrates the rotor along a rotation axis; nozzles that are disposed opposite to an axial end surface of the rotor, inject a cooling oil toward openings of the cooling oil paths formed on the axial end surface, and feed the cooling oil to the cooling oil paths; and an oil pump that discharges the sucked cooling oil to the nozzles. The oil pump is driven by rotation of the shaft.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine. [Background technology]

[0002] Magnets housed in the rotor of a rotating electric machine can experience a phenomenon in which magnetic flux decreases at high temperatures (high-temperature demagnetization). Such high-temperature demagnetization can be suppressed, for example, by using magnets with a high content of heavy rare earth elements, but this leads to increased manufacturing costs for the rotating electric machine. Generally, rotors are air-cooled by dissipating heat into the air, but from the perspective of improving the performance of rotating electric machines, more efficient cooling of the rotor is desired.

[0003] As an example, a rotor cooling structure has been proposed in which a refrigerant such as insulating oil is supplied to a hole penetrating the rotor from one axial side of the rotor using a refrigerant supply piping arranged inside the case of a rotating electric machine (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-184343 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the refrigerant supply device of the cited document 1, the refrigerant supply pipe is arranged from above so as to face the upper region of the rotor, and the refrigerant is supplied to the holes of the rotor. Therefore, the path from the bottom of the case to the discharge port of the refrigerant supply pipe is relatively long, and a high-output pump must be used to deliver the refrigerant to the rotor, leaving room for improvement.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a rotating electric machine that can more efficiently deliver cooling oil to a cooling oil passage that penetrates a rotor. [Means for solving the problem]

[0007] A rotating electric machine according to one aspect of the present invention includes a rotor having a plurality of cooling oil passages arranged in a circumferential direction, a shaft penetrating the rotor along a rotation axis, a nozzle arranged opposite an axial end face of the rotor and configured to inject cooling oil toward an opening of the cooling oil passage formed in the axial end face to supply the cooling oil to the cooling oil passage, and an oil pump configured to discharge the sucked cooling oil to the nozzle. The oil pump is driven by the rotation of the shaft.

[0008] In the above rotating electric machine, the nozzle and the oil pump may be disposed on the anti-load side of the rotating electric machine, or may be incorporated in a bracket of a housing that houses the rotating electric machine. The rotating electric machine may further include an end plate disposed on one axial end surface of the rotor. The end plate may have an oil guide disposed on an outer circumferential side of the opening for receiving the cooling oil sprayed from the nozzle and guiding the cooling oil to the opening. Effect of the Invention

[0009] According to one aspect of the present invention, it is possible to provide a rotating electric machine that can more efficiently deliver cooling oil to a cooling oil passage that penetrates a rotor. [Brief description of the drawings]

[0010] [Figure 1] 1 is a front view showing an example of the configuration of a rotating electric machine according to an embodiment of the present invention; [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiments, in order to make the description easier to understand, structures and elements other than the main parts of the present invention will be described in a simplified or omitted manner. In addition, in the drawings, the same elements are given the same reference numerals. Note that the shapes, dimensions, etc. of each element shown in the drawings are shown only for illustrative purposes, and do not represent the actual shapes, dimensions, etc.

[0012] In the following description, the direction parallel to the extension direction of the rotation axis Ax will be referred to as the axial direction, the circumferential direction centered on the rotation axis Ax will be simply referred to as the circumferential direction, and the radial direction centered on the rotation axis Ax will be simply referred to as the radial direction.

[0013] Fig. 1 is a front view showing a configuration example of a rotating electric machine 1 according to the present embodiment, Fig. 2 is a cross-sectional view taken along line AA in Fig. 1, and Fig. 3 is a front view of a rotor.

[0014] The rotating electric machine 1 of this embodiment is, for example, an inner rotor type motor applied to a vehicle motor, etc. The rotating electric machine 1 has a rotor 2, a cylindrical stator 3 arranged on the outer periphery of the rotor 2, and a housing 4. In Fig. 1 and Fig. 3, the extension direction of the rotation axis AX of the rotating electric machine 1 is perpendicular to the plane of the paper.

[0015] The rotor 2 is, for example, a magnet-embedded type or a surface magnet type rotor. The core of the rotor 2 is cylindrical and is formed, for example, by laminating stamped silicon steel plates in an insulated state in the axial direction. A shaft 5 is inserted into the center of the rotor 2 so as to penetrate the core along the rotation axis Ax.

[0016] A plurality of permanent magnets (not shown) are arranged in the core of the rotor 2 so as to form main poles at equal intervals along the circumferential direction. Each permanent magnet is arranged in the core of the rotor 2 so as to extend along the axial direction.

[0017] Furthermore, a plurality of through holes 6 are formed in the iron core of the rotor 2 along the circumferential direction. Each through hole 6 is circular and extends axially through the iron core of the rotor 2. The through holes 6 function as cooling oil paths for flowing cooling oil inside the rotor 2, and also reduce stress caused by centrifugal force by reducing the weight of the rotor 2, thereby suppressing deformation and cracking of the iron core of the rotor 2.

[0018] End plates 7a, 7b are attached to both axial end faces of the rotor 2. The end plates 7a, 7b are disk-shaped members with a smaller diameter than the rotor 2 and a hole through which the shaft 5 is inserted in the center. The end plate 7a, which is arranged on one side (right side in FIG. 2), abuts against the axial end face of the rotor 2 on one side. The end plate 7b, which is arranged on the other side (left side in FIG. 2), abuts against the axial end face of the rotor 2 on the other side. The end plates 7a, 7b press down on the rotor 2 from both axial sides and hold the iron core of the rotor 2, which is made of laminated steel plates.

[0019] 2, the end plates 7a, 7b each have a circular opening 7c at a position corresponding to the through hole 6 of the iron core of the rotor 2. As a result, the through hole 6 of the rotor 2 communicates from one side to the other side of the rotor 2 without being blocked by the end plates 7a, 7b.

[0020] As shown in FIG. 3, the end plate 7a on one side is provided with a protrusion 7d that protrudes in the axial direction. The protrusion 7d is an example of an oil guide, and is provided so as to form an annular shape in the circumferential direction on the outer periphery side of the opening 7c. A plurality of grooves 7e each extending in the radial direction are formed on the end face on one side of the protrusion 7d. The plurality of grooves 7e are provided on the protrusion 7d so as to form a radial shape at predetermined intervals in the circumferential direction, for example. The shape of the end plate 7b on the other side may be the same as or different from the shape of the end plate 7a on the one side.

[0021] The stator 3 has an overall cylindrical shape and houses the rotor 2 across a small air gap in a central space centered on the rotation axis Ax. The iron core of the stator 3 has a plurality of slots (not shown) formed in a comb-tooth shape on the radially inner side, and a coil 8 is disposed in each slot.

[0022] The housing 4 of the rotating electric machine 1 has a cylindrical space that is open on both axial sides. A rotor 2 into which a shaft 5 is fitted and a stator 3 are concentrically arranged inside the housing 4. The stator 3 is fitted into the inner periphery of the housing 4, and the housing 4 is attached so as to cover the outer periphery of the stator 3.

[0023] Brackets 10a, 10b are attached to both sides of the housing 4 in the axial direction. As a result, openings on both sides of the housing 4 are closed by the brackets 10a, 10b. Also, a bearing 9 is provided in each of the brackets 10a, 10b, and the shaft 5 is rotatably supported by the bearings 9 of the brackets 10a, 10b. The other end of the shaft 5, which is the load side of the rotating electric machine 1, penetrates the bracket 10b on the other side and protrudes outward.

[0024] A cooling mechanism 11 that supplies cooling oil to the rotor 2 is mounted on a bracket 10a on one side, which is the anti-load side, of the rotating electrical machine 1. The cooling mechanism 11 has oil passages 12a and 12b, an oil pump 13, and discharge nozzles 14a and 14b.

[0025] The oil passages 12a and 12b are each built into the bracket 10a, and are arranged in a region (hereinafter also referred to as a lower region) below the position of the shaft 5 in the bracket 10a, as shown by a broken line in FIG. 1. The oil passage 12a extends in the vertical direction in FIG. 1 in the lower region of the bracket 10a. One end of the oil passage 12a is connected to a bottom region in the housing 4 that functions as an oil pan, and the other end of the oil passage 12a is connected to the suction side of the oil pump 13. The oil passage 12b extends in a rightward diagonal direction in FIG. 1 in the lower region of the bracket 10a. One end of the oil passage 12b is connected to the discharge side of the oil pump 13, and the other end of the oil passage 12b branches off and is connected to two discharge nozzles 14a and 14b, respectively.

[0026] The oil pump 13 is an internal gear type pump arranged on one side of the bracket 10a, and has an external gear 13a and an internal gear 13b that fits inside the external gear 13a. The internal gear 13b of the oil pump 13 is connected to one side of the shaft 5 and rotates following the shaft 5. The oil pump 13 performs a pumping action by changing the volume of the space formed between the external gear 13a and the internal gear 13b as the internal gear 13b rotates while meshing with the external gear 13a. As a result, the oil pump 13 sucks cooling oil from the oil passage 12a and discharges the cooling oil to the oil passage 12b.

[0027] Discharge nozzles 14a and 14b are attached to the inner surface of bracket 10a so as to face end plate 7a on one side of rotor 2. As shown by dashed lines in Fig. 3, discharge nozzle 14a is disposed at a position corresponding to opening 7c of end plate 7a, and discharge nozzle 14b is disposed at a position radially outward of protrusion 7d of end plate 7a.

[0028] Next, the operation of the rotating electric machine 1 in this embodiment will be described. In the rotating electric machine 1, the magnetic field of the stator 3 is switched in sequence by controlling the current of the coil 8 of the stator 3, which generates an attractive or repulsive force between the stator 3 and the magnetic field of the rotor 2. This causes the rotor 2 and the shaft 5 to rotate about the rotation axis Ax, driving the rotating electric machine 1. At this time, the permanent magnets housed in the rotor 2 also become heated by electromagnetic induction.

[0029] Furthermore, the internal gear 13b of the oil pump 13 rotates in response to the rotation of the shaft 5. This causes the oil pump 13 to suck the cooling oil from the oil passage 12a and discharge the cooling oil to the oil passage 12b. The cooling oil in the oil passage 12b is sprayed from the discharge nozzles 14a and 14b toward the end plate 7a on one side of the rotor 2.

[0030] A portion of the cooling oil discharged from the discharge nozzle 14a flows directly from the opening 7c of the end plate 7a into the through hole 6 of the rotor 2 and flows axially from one side to the other side of the rotor 2. Inside the through hole 6, the iron core of the rotor 2 is cooled by heat exchange with the cooling oil, and this also cools the permanent magnets over the entire axial direction. The cooling oil after heat exchange is discharged to the outside of the rotor 2 from the opening 7c of the end plate 7b located on the other side of the through hole 6. The cooling oil discharged to the outside of the rotor 2 flows back to the bottom region of the housing 4.

[0031] Furthermore, the cooling oil discharged from the discharge nozzle 14a into the opening 7c of the end plate 7a is guided to the protrusion 7d of the end plate 7a by the centrifugal force of the rotor 2, and then flows along the inner circumference of the protrusion 7d in the rotational direction of the rotor 2. The cooling oil flowing along the protrusion 7d flows into the opening 7c on the downstream side in the rotational direction, and some of it passes through the groove of the protrusion 7d and is guided to the outer periphery of the protrusion 7d, where it joins with the cooling oil discharged from the discharge nozzle 14b.

[0032] The cooling oil discharged from the discharge nozzle 14b comes into contact with the surface of the end plate 7a and removes heat from the end plate 7a. This cools one end face of the rotor 2 through the end plate 7a. The cooling oil then flows back to the lower region of the housing 4. The cooling oil that has returned to the bottom region of the housing 4 is again sent toward the discharge nozzles 14a and 14b by the drive of the oil pump 13.

[0033] As described above, the rotating electric machine 1 of this embodiment includes a cooling mechanism 11 having a discharge nozzle 14a and an oil pump 13. The discharge nozzle 14a is disposed opposite the end plate 7a on the axial end face of the rotor 2, and injects cooling oil toward the opening 7c of a cooling oil passage formed in the end plate 7a, thereby supplying the cooling oil to the cooling oil passage. The oil pump 13 is driven by the rotation of the shaft 5, and discharges the sucked cooling oil to the discharge nozzle 14a. According to this embodiment, the cooling oil can be supplied to the cooling oil passage of the rotor 2 by driving the oil pump 13 using the power of the rotating electric machine 1, so that it is not necessary to provide a separate power source for the oil pump 13, and the cooling oil can be more efficiently delivered to the cooling oil passage of the rotor 2.

[0034] In this embodiment, the cooling mechanism 11 is disposed on the anti-load side of the rotating electric machine 1, thereby simplifying the structure of the load side of the rotating electric machine 1, which requires less space. Furthermore, the cooling mechanism 11 is incorporated into the bracket 10a of the housing 4, thereby facilitating the assembly work of the rotating electric machine 1. In addition, the end plate 7a of this embodiment has a protrusion 7d on the outer periphery of the opening 7c that guides the cooling oil to the opening 7c, making it easier to guide the cooling oil from the discharge nozzle 14a to each cooling oil passage, thereby preventing a decrease in the cooling efficiency within the rotor 2.

[0035] The present invention is not limited to the above-described embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.

[0036] For example, in the above embodiment, the rotating electric machine 1 is a motor, but the rotating electric machine 1 may be a generator. Further, in the above embodiment, the oil pump 13 is described as an example in which a gear is directly connected to the shaft 5. However, the power of the shaft may be transmitted to the oil pump via, for example, a chain or the like.

[0037] In the above embodiment, the discharge nozzle 14a is disposed at a position corresponding to the opening 7c of the end plate 7a, but the present invention is not limited to the above configuration. For example, the position of the discharge nozzle 14a may be shifted radially inward from the opening 7c, and the cooling oil from the discharge nozzle 14a may be sprayed once onto the end plate 7a, and the cooling oil may be guided to the opening 7c by an oil guide. Furthermore, in the above embodiment, in addition to the discharge nozzle 14a, the discharge nozzle 14b is provided on the outer periphery side of the opening 7c of the end plate 7a, but the discharge nozzle 14b is not necessarily provided.

[0038] In addition, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0039] 1... rotating electric machine, 2... rotor, 3... stator, 4... housing, 5... shaft, 6... through hole, 7a, 7b... end plate, 7c... opening, 7d... protrusion, 7e... groove, 8... coil, 9... bearing, 10a, 10b... bracket, 11... cooling mechanism, 12a, 12b... oil passage, 13... oil pump, 14a, 14b... discharge nozzle

Claims

1. a rotor having a plurality of cooling oil passages formed to penetrate the rotor in an axial direction and arranged in a circumferential direction; a shaft passing through the rotor along a rotation axis; a nozzle disposed opposite an axial end surface of the rotor and configured to inject cooling oil toward an opening of the cooling oil passage formed in the axial end surface, thereby supplying the cooling oil to the cooling oil passage; an oil pump that discharges the sucked cooling oil to the nozzle, The oil pump is driven by the rotation of the shaft. Rotating electric motor.

2. The nozzle and the oil pump are disposed on the anti-load side of the rotating electric machine. The rotating electric machine according to claim 1 .

3. The nozzle and the oil pump are incorporated into a bracket of a housing that houses a rotating electrical machine. The rotating electric machine according to claim 2 .

4. An end plate is further provided on one axial end surface of the rotor, The end plate has an oil guide on an outer circumferential side of the opening, the oil guide directing the cooling oil sprayed from the nozzle to the opening. The rotating electric machine according to any one of claims 1 to 3.

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