Motor device

Abstract

To provide a motor device that can block heat from the motor and provide reliable insulation protection. [Solution] The motor device 1 includes a stator 10 around which a coil 33 is wound, a rotor 11 rotatably mounted relative to the stator 10, a motor housing 14 housing the stator 10 and the rotor 11, a bearing 22R that rotatably supports the rotation axis 12 of the rotor 11, a bearing housing 19 that holds the bearing 22R, a substrate 17 positioned at the end of the motor housing 14 opposite to the stator 10, sandwiching the bearing housing 19, and controlling the rotation of the rotor 11, and a heat shield plate 18 positioned between the bearing housing 19 and the substrate plate 17 to prevent heat generated in the motor housing 14 from being transferred to the substrate plate 17. The bearing housing 19 has a hole 53 into which a busbar terminal 51 is inserted, and the inner surface of the hole 53 is covered with the heat shield plate 18.

Description

Technical Field

[0001] The present invention relates to a motor device used for a drive source of a vehicle or the like.

Background Art

[0002] Generally, an inverter circuit element of a motor device used for a drive source of a vehicle or the like is susceptible to heat. However, in response to the demand for miniaturization of the motor device, there is a case where a so-called mechatronic motor is used, in which a motor and a substrate on which an inverter circuit element is mounted are integrated. In this mechatronic motor, the motor and the substrate are incorporated inside a motor housing. In such a motor device, various techniques have been proposed to suppress heat damage to the substrate.

[0003] For example, a technique has been proposed in which a motor and a substrate are partitioned by an intermediate bracket. A metal bearing housing is attached to the intermediate bracket. This increases the rigidity of the intermediate bracket and enables the rotor of the motor to be rotatably supported. The connection between the stator of the motor and the substrate is made through terminals that penetrate the bearing housing and the intermediate bracket.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the above-described conventional technology, the bearing housing is made of metal, and the influence of the heat generated by the motor is large. When the motor is continuously used, the ambient temperature around the circuit may increase, and there is a possibility that the performance cannot be fully exhibited. In addition, the insulation protection of the terminals is insufficient, and there is a possibility of short-circuiting with the bearing housing.

[0006] Therefore, the present invention provides a motor device that can block heat from the motor and provide reliable insulation protection. [Means for solving the problem]

[0007] To solve the above problems, a motor device according to a first aspect of the present invention comprises a stator around which a coil is wound, a rotor rotatably mounted relative to the stator and having a rotating shaft, a motor housing housing the stator and the rotor, a bearing housing that rotatably supports the rotating shaft via a bearing, a substrate disposed at the end of the motor housing opposite to the stator, sandwiching the bearing housing, and controlling the rotation of the rotor, and a heat shield plate disposed between the bearing housing and the substrate to prevent heat generated in the motor housing from being transferred to the substrate, wherein the stator has a plurality of terminals protruding toward the substrate, the bearing housing has holes into which the terminals are inserted, and the inner surface of the holes is covered by the heat shield plate.

[0008] In this way, by covering the inner surface of the hole in the bearing housing with a heat shield, the terminals can be insulated and protected, and heat transfer to the circuit board can be suppressed. By giving the heat shield both heat shielding and insulating protection functions, the number of parts can be reduced.

[0009] In a second aspect of the present invention, in the motor device of the first aspect, the heat shield plate has an insulating cylindrical portion that fits into the hole, and the inner surface of the hole is covered by the insulating cylindrical portion.

[0010] This configuration allows for easy manufacturing of heat shields and bearing housings. By simply fitting the insulating cylinder into the hole, the inner surface of the hole can be covered with a heat shield. This improves ease of assembly.

[0011] In a third aspect of the present invention, in the motor device of the first or second aspect, the surface of the heat shield is formed in a honeycomb structure.

[0012] By configuring it in this way, the rigidity of the heat shield can be improved, allowing the heat shield to be made thinner.

[0013] In a fourth aspect of the present invention, in the motor device of the third aspect, the honeycomb structure is formed on the surface facing the bearing housing.

[0014] By configuring it in this way, an air layer is created between the heat shield and the bearing housing, which improves the heat insulation effect.

[0015] In a fifth aspect of the present invention, the motor device of the first or second aspect is provided with a cover for housing the substrate, and the heat shield is sandwiched between the bearing housing and the cover.

[0016] This configuration eliminates the need to form screw or fixing structures on the heat shield, thus reducing the number of parts such as bolts.

[0017] In a sixth aspect of the present invention, the motor device of the first or second aspect is further provided with a radiant heat plate disposed between the heat shield plate and the bearing housing.

[0018] By configuring it in this way, in addition to the heat insulation effect, it is also possible to block or reflect heat such as radiant heat, further suppressing heat transfer to the substrate side. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a motor device that can block heat from the motor and provide reliable insulation protection. [Brief explanation of the drawing]

[0020] [Figure 1] This is a perspective view of the motor device of the embodiment. [Figure 2] This is a side view of the motor device of the embodiment. [Figure 3]It is a perspective exploded view of the motor device of the embodiment. [Figure 4] It is a cross-sectional view taken along line IV-IV of FIG. 1. [Figure 5] It is a perspective view of the motor device of the embodiment with some parts removed. [Figure 6] It is a perspective view of the heat shield included in the motor device of the embodiment. [Figure 7] It is a cross-sectional perspective view showing the heat shield structure of the motor device of the embodiment. [Figure 8] It is an enlarged perspective view of part VIII in FIG. 4. [Figure 9] It is an enlarged view of part IX in FIG. 7.

Mode for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0022] <Motor Device> FIG. 1 is a perspective view of the motor device 1. FIG. 2 is a side view of the motor device 1. FIG. 3 is a perspective exploded view of the motor device 1. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 1. The motor device 1 is used, for example, as a drive source for an electric motorcycle. The motor device 1 is, for example, a three-phase brushless motor.

[0023] As shown in FIGS. 1 to 4, the motor device 1 mainly includes a motor unit 2 and a substrate 17. The motor unit 2 includes an annular stator 10 and a rotor 11 provided rotatably with respect to the stator 10 inside the stator 10 in the radial direction. A minute gap (air gap) is secured between the outer peripheral surface of the rotor 11 and the stator 10. The rotor 11 has a rotating shaft 12 at the axial center position.

[0024] The stator 10 and rotor 11 are housed inside the housing 13. The housing 13 comprises a bottomed cylindrical motor housing 14, a power control unit (PCU) cover (hereinafter referred to as the PCU cover) 15 that closes one axial end of the motor housing 14, and a vehicle body mounting bracket 16 attached to the motor housing 14 on the side opposite to the PCU cover 15.

[0025] The stator 10 and rotor 11 are housed within the motor housing 14. The PCU cover 15 and the vehicle mounting bracket 16 are fixed to the motor housing 14 by bolts or the like. These motor housing 14, PCU cover 15, and vehicle mounting bracket 16 are made of metal such as aluminum. Inside this housing 13, the circuit board 17, heat shield 18, radiant heat plate 4, bearing housing 19, and motor unit 2 are arranged in order from the PCU cover 15 side.

[0026] In other words, the PCU cover 15 houses the circuit board 17. The circuit board 17 is located at the end of the motor housing 14 where the bearing housing 19 is positioned, and controls the rotation of the rotor 11. The heat shield 18 prevents or reduces the transfer of heat generated from the stator 10 and rotor 11 to the substrate 17. The radiant heat shield 4 blocks or reflects the radiant heat generated in the motor section 2, preventing or reducing its transfer to the substrate 17.

[0027] In addition to the stator 10 and rotor 11, the motor unit 2 includes a busbar unit (three-phase terminal) 50, which will be described later. The bearing housing 19 is formed in a disc shape and acts as a partition between the motor section 2 and the PCU cover 15 side. Annular gaskets 22 are attached to both sides of the bearing housing 19, on the PCU cover 15 side and the vehicle body mounting bracket 16 side.

[0028] The stator 10 is integrally molded with a cylindrical core portion 31 and a plurality of teeth portions 31b (for example, 12 in this embodiment) that project radially inward from the inner circumferential surface of the core portion 31. The teeth portions 31b are formed in a T-shape when viewed from the axial direction. The core portion 31 and the teeth portions 31b are formed, for example, by laminating a plurality of electromagnetic steel sheets in the axial direction. The periphery of each tooth portion 31b is covered by an insulator 32. A coil 33 is wound around each tooth portion 31b from above the insulator 32.

[0029] The rotor 11 includes a rotating shaft 12 and a cylindrical rotor body 20 fitted and fixed to the rotating shaft 12. The rotor body 20 is formed, for example, by stacking multiple electromagnetic steel sheets in the axial direction. Multiple permanent magnets (not shown) are embedded in the rotor body 20. The multiple permanent magnets are arranged so that, in the circumferential direction of the rotor body 20, the north poles and south poles alternately appear facing radially outward.

[0030] Thus, the rotor 11 employs a so-called "IPM (Interior Permanent Magnet) structure" in which multiple permanent magnets are embedded inside the rotor body 20. However, it is not limited to this, and the rotor 11 can also employ a so-called "SPM (Surface Permanent Magnet) structure" in which permanent magnets are attached to the outer surface of the rotor body 20.

[0031] The rotating shaft 12 has two ends protruding from the rotor body 20: a first end 12a (towards the PCU cover 15) and a second end 12b (towards the vehicle mounting bracket 16), opposite to the first end 12a. The first end 12a of the rotating shaft 12 is rotatably supported by the bearing housing 19 via a bearing 22R. The second end 12b of the rotating shaft 12 passes through the bottom of the motor housing 14. In this state, it is rotatably supported by the motor housing 14 via a bearing 22F. The end of the rotating shaft 12 that passes through the bottom of the motor housing 14 functions as a rotating output section to which output gears and sprockets are attached.

[0032] Inside the PCU cover 15, a substrate chamber 23 is formed, which is a space for housing a substrate 17 and the like. The first end 12a of the rotating shaft 12 protrudes into the PCU cover 15 so as to be exposed into the substrate chamber 23. A disc-shaped sensor magnet 24 is fixed to the end face of the first end 12a of the rotating shaft 12. The sensor magnet 24 serves as a detection target for detecting the rotation state when the rotation state of the rotor 11 (rotating shaft 12) is detected by the rotation sensor 25, which will be described later.

[0033] A rotation sensor 25 is mounted on the circuit board 17 at a location opposite the sensor magnet 24 in the axial direction. The circuit board 17 is arranged such that the rotation sensor 25 faces the sensor magnet 24 with a small gap between them. The circuitry on the board 17 is connected to a controller (not shown) via a harness 52 and sensor connector 49 provided on the PCU cover 15.

[0034] Figure 5 is a perspective view of the exposed heat shield 18 after some components of the motor device 1 have been removed. As shown in Figures 3 to 5, the stator 10 includes an annular busbar unit 50 located at the end on the PCU cover 15 side. The busbar unit 50 has three-phase terminals of busbar terminals 51 (U-phase busbar terminal 51U, V-phase busbar terminal 51V, and W-phase busbar terminal 51W) for supplying drive current to the coils 33 wound around each tooth portion 31b. The three-phase terminals have a cross-sectional shape along the axial direction that is a U-shape turned on its side (a U-shape). The busbar terminals 51U, 51V, and 51W protrude towards the substrate 17 side. That is, the stator 10 has three-phase terminals of busbar terminals 51U, 51V, and 51W that protrude axially towards the substrate 17 side.

[0035] The bearing housing 19 has holes 53 formed at positions corresponding to the three-phase terminals of the busbar terminals 51U, 51V, and 51W. The busbar terminals 51U, 51V, and 51W protrude towards the circuit board 17 through these holes 53. The tips of the protruding busbar terminals 51U, 51V, and 51W are connected to connection terminals 48 extending from the circuit board 17.

[0036] The connection terminal 48 is formed from a conductive metal plate and is positioned so that its thickness direction is oriented axially. Busbar terminals 51U, 51V, and 51W are connected to this connection terminal 48 from the motor unit 2 side. In this way, the stator 10 and a controller (not shown) are electrically connected via the connection terminal 48 and the busbar terminals 51U, 51V, and 51W.

[0037] Figure 6 is a perspective view of the heat shield 18. As shown in Figure 6, the heat shield 18 is formed in a disc shape using resin. Examples of resins used include PPT (polypropylene terephthalate) resin and PPS (polyphenylene sulfide) resin. However, it is not limited to these; any resin with heat-shielding properties is acceptable, and various resins can be used. The heat shield plate 18 faces the bearing housing 19 during the assembly of the motor device 1, and the surface of the heat shielding surface 41, which serves as a heat shield, is formed in a honeycomb structure. This honeycomb structure is formed on the surface of the heat shielding surface 41 of the heat shield plate 18 that faces the bearing housing 19.

[0038] Furthermore, the heat shield 18 has three heat shield holes 42 that fit into the three holes 53 of the bearing housing 19. With this configuration, when assembling the motor device 1, the three phase terminals of the busbar terminals 51U, 51V, and 51W are inserted into each heat shield hole 42 along with the holes 53 of the bearing housing 19. In addition, an insulating cylindrical portion 43 is formed around the heat shield holes 42, which is raised on the wall surface.

[0039] With this configuration, when assembling the motor unit 1, the heat shield 18 is placed on top of the bearing housing 19, and the insulating cylindrical portion 43 is fitted into the hole 53 of the bearing housing 19. As a result, the inner surface of the hole 53 of the bearing housing 19 is covered by the heat shield 18. Therefore, a short circuit between the busbar terminals 51U, 51V, 51W and the housing 13 and the bearing housing 19 can be prevented.

[0040] Next, the heat transfer within the housing 13 will be described based on Figures 3 and 7. Figure 7 is a cross-sectional perspective view showing the heat shielding structure of the motor device 1. When power is supplied to the motor unit 2 of the motor device 1, heat is generated in the motor unit 2 of the motor housing 14. This heat is transferred to the rotating shaft 12 and the motor housing 14. Furthermore, the heat transferred to the rotating shaft 12 is transferred to the bearing 22R that rotatably supports the PCU cover 15 side of the rotating shaft 12 in the axial direction. Since the bearing 22R is held in a metal bearing housing 19, the heat transferred to the bearing 22R is transferred to the bearing housing 19.

[0041] As shown in Figure 7, the motor device 1 is equipped with a heat shield plate 18 between the motor unit 2 and the substrate 17 in the substrate chamber 23. This configuration shields the heat transmitted from the motor unit 2 to the motor housing 14 and bearing housing 19, preventing it from being transmitted to the substrate 17.

[0042] Next, the insulation structure of the three-phase terminals will be described based on Figures 3, 6, and 8. Figure 8 is an enlarged perspective view of section VIII in Figure 4. As shown in Figure 8, the three-phase terminals of the busbar terminals 51U, 51V, and 51W are inserted into the heat shield holes 42 of the heat shield 18, along with the holes 53 of the bearing housing 19. An insulating cylindrical portion 43 is formed around the heat shield holes 42, rising on the wall surface toward the motor section 2.

[0043] With this configuration, when assembling the motor unit 1, the inner surface of the hole 53 in the bearing housing 19 is covered by the insulating cylindrical portion 43 of the heat shield plate 18. As a result, the three-phase wire terminals can be isolated from the metal motor housing 14 and the metal bearing housing 19 (parts A and B in Figure 8). Therefore, the motor unit 1 can prevent short circuits between the busbar terminals 51U, 51V, and 51W and the housing 13 and bearing housing 19, and can insulate and protect the three-phase wire terminals.

[0044] Next, the fixing structure of the heat shield 18 will be described based on Figure 9. Figure 9 is an enlarged view of section IX in Figure 7. As shown in Figure 9, the PCU cover 15 has a cover recess 55 formed at a position that contacts the end of the heat shield 18. The bearing housing 19 has a housing recess 56 formed at a position opposite to the cover recess 55 and that contacts the end of the heat shield 18.

[0045] These cover recesses 55 and housing recesses 56 form a recess, and the outer edge of the heat shield 18 is positioned in this recess. This positions the heat shield 18 radially. Furthermore, the outer edge of the heat shield 18 is clamped between the PCU cover 15 and the bearing housing 19 to fix the heat shield 18 in place. By clamping the heat shield 18 between the bearing housing 19 and the PCU cover 15 in this way, the number of parts required to fix the heat shield 18 can be reduced.

[0046] <Operation of electric motor> Multiple coils 33 of the stator 10 are supplied with drive current via the controller's drive circuit and the three-phase terminals 51U, 51V, and 51W of the busbar terminals. When drive current is supplied to the coils 33 in this way, a rotating magnetic field is generated in the stator 10. Magnetic attractive and repulsive forces are generated between this magnetic field and the permanent magnets of the rotor 11. As a result, the rotor 11 rotates in a predetermined direction.

[0047] <Effects of the Embodiment> As described above, the motor device 1 of this embodiment is equipped with a heat shield plate 18 positioned between the bearing housing 19 and the substrate 17, which prevents heat generated in the motor housing 14, such as the stator 10 and rotor 11, from being transferred to the substrate 17. The stator 10 has busbar terminals 51U, 51V, and 51W that protrude toward the substrate 17. The bearing housing 19 has holes 53 into which the busbar terminals 51U, 51V, and 51W are inserted, and the inner surface of the holes 53 is covered with the heat shield plate 18.

[0048] This configuration suppresses heat transfer to the substrate 17, and the heat shield 18 covers the inner surface of the hole 53 in the bearing housing 19, thereby providing insulating protection for the three-phase wire terminals. Furthermore, the heat shield 18 also functions as an insulator 32 to prevent short circuits between the connection between the motor unit 2 and the three-phase wire terminals and the aluminum housing 13 or the aluminum bearing housing 19, thereby reducing the number of components.

[0049] The heat shield 18 has an insulating cylindrical portion 43 that fits into the hole 53 of the bearing housing 19. Therefore, when covering the inner surface of the hole 53 with the heat shield 18, the heat shield 18 and the bearing housing 19 can be easily manufactured. The inner surface of the hole 53 can be covered with the heat shield 18 simply by fitting the insulating cylindrical portion 43 into the hole 53. This improves ease of assembly.

[0050] The surface of the heat shield 18 is formed in a honeycomb structure. This configuration improves the rigidity of the heat shield 18, allowing it to be made as thin as, for example, 2 mm thick. This honeycomb structure is formed on the surface of the heat shield plate 18 facing the bearing housing 19. This configuration creates an air layer between the heat shield plate 18 and the bearing housing 19, improving the heat insulation effect.

[0051] The motor unit 1 further includes a PCU cover 15 that houses the circuit board 17. The heat shield 18 is sandwiched between the bearing housing 19 and the PCU cover 15. This configuration eliminates the need to form screw structures or fixing structures on the heat shield 18, thereby reducing the number of parts such as bolts 5.

[0052] The motor device 1 is further equipped with a radiant heat plate 4 between the heat shield plate 18 and the bearing housing 19. With this configuration, in addition to the heat insulation effect, the effect of reflecting heat such as radiant heat can also be obtained, and the transfer of heat from the motor unit 2 to the substrate 17 can be further suppressed.

[0053] Therefore, according to the motor device 1 of this embodiment, the heat shield 18 blocks the electric heat from the motor unit 2, preventing the temperature of the substrate chamber 23 from rising and preventing performance degradation and loss of function of the circuit elements on the substrate 17, thereby enabling the integration of the motor and inverter. Furthermore, since the heat shield 18 also has the function of insulating and protecting the three-phase wire terminals, the number of parts in the motor device 1 can be reduced.

[0054] By preventing performance degradation and loss of function due to thermal damage to the motor device 1, and by providing insulation protection for the three-phase wire terminals, it becomes possible to contribute to the United Nations-led Sustainable Development Goal (SDG) 7, "Ensure access to affordable, reliable, sustainable, and modern energy for all," and Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation."

[0055] The present invention is not limited to the embodiments described above, but includes various modifications to the embodiments described above, without departing from the spirit of the invention.

[0056] For example, in the above-described embodiment, the motor device 1 was described in the case where it is used as a drive source for an electric motorcycle. However, it is not limited to this, and the configuration of the motor device 1 described above can be adopted for various electric devices. In the above-described embodiment, the motor device 1 was described as, for example, a brushless motor with a three-phase structure. However, it is not limited to this, and the above-described configuration of the motor device 1 can also be adopted for motor devices other than those with a three-phase structure. In other words, the number of terminals is not limited to three.

[0057] In the above-described embodiment, a heat shield 18 made of resin was used. However, it is not limited to this, and other materials may be used for the heat shield 18 as long as they have an insulating effect or low thermal conductivity. Furthermore, the heat shield 18 is not limited to a plate; it may also be in the form of a panel or a sheet.

[0058] In this embodiment, the surface of the heat-shielding surface 41 of the heat shield 18 is formed in a honeycomb structure, but it may be formed in other polygonal structures such as triangles or squares, as long as it is rigid and allows the heat shield 18 to be made thinner. Also, although the honeycomb structure is formed on the surface of the heat-shielding surface 41 of the heat shield 18 on the side facing the bearing housing 19, it may also be formed on the surface of the heat shield 18 on the side facing the substrate 17.

[0059] In this embodiment, the radiant heat plate 4 has been described as being placed between the heat shield 18 and the bearing housing 19, but any material that blocks or reflects the radiant heat generated in the motor section 2 may be used, such as mirror-finished aluminum foil or aluminum sheet. It may also be deposited onto other components such as the heat shield 18. The radiant heat plate 4 may also be placed on the surface of the heat shield 18 on the substrate 17 side. The radiant heat plate 4 does not need to be provided.

[0060] In this embodiment, the housing 13 and bearing housing 19 have been described in the case where aluminum components are used. However, the invention is not limited to this, and the housing 13 and bearing housing 19 may be made of metal components other than aluminum.

[0061] In the above-described embodiment, a case was explained in which a cover recess 55 is formed in the PCU cover 15 and a housing recess 56 is formed in the bearing housing 19. A case was explained in which a recess is formed by these cover recess 55 and housing recess 56, and the outer peripheral edge of the heat shield 18 is placed in this recess. However, the invention is not limited to this, and a recess may be formed in at least one of the PCU cover 15 or the bearing housing 19. Even in this configuration, radial positioning of the heat shield 18 can be performed. [Explanation of Symbols]

[0062] 1...Motor unit, 2...Motor section, 4...Radiant heat plate, 5...Bolt, 10...Stator, 11...Rotor, 12...Rotating shaft, 12a...First end, 12b...Second end, 13...Housing, 14...Motor housing, 15...Power control unit cover, 16...Vehicle mounting bracket, 17...Circuit board, 18...Heat shield, 19...Bearing housing, 20...Rotor body, 22...Gasket, 22F...Bearing, 22R...Bearing, 23...Circuit board chamber, 24...Sensor 25... Rotation sensor, 31... Core part, 31b... Teeth part, 32... Insulator, 33... Coil, 41... Heat shield surface, 42... Heat shield hole part, 43... Insulating cylinder part, 48... Connection terminal, 49... Sensor connector, 50... Busbar unit, 51... Busbar terminal, 51U... U-phase busbar terminal, 51V... V-phase busbar terminal, 51W... W-phase busbar terminal, 52... Harness, 53... Hole part, 55... Cover recess part, 56... Housing recess part

Claims

1. The stator around which the coil is wound, A rotor rotatably mounted relative to the stator and having a rotation axis, A motor housing that houses the stator and the rotor, A bearing housing that rotatably supports the aforementioned rotating shaft via a bearing, A circuit board is positioned at the end of the motor housing opposite to the stator, with the bearing housing in between, and controls the rotation of the rotor. A heat shield is placed between the bearing housing and the substrate to prevent heat generated in the motor housing from being transferred to the substrate, Equipped with, The stator has a plurality of terminals protruding toward the substrate, The bearing housing has a hole into which the terminal is inserted, The inner surface of the hole is covered by the heat shield plate. Motor device.

2. The heat shield plate has an insulating cylindrical portion that fits into the hole, and the inner surface of the hole is covered by the insulating cylindrical portion. The motor device according to claim 1.

3. The surface of the heat shield is formed in a honeycomb structure. The motor device according to claim 1 or claim 2.

4. The motor device according to claim 3, wherein the honeycomb structure is formed on the surface facing the bearing housing.

5. It comprises a cover for housing the aforementioned substrate, The heat shield is sandwiched between the bearing housing and the cover. The motor device according to claim 1 or claim 2.

6. The system includes a radiant heat plate positioned between the heat shield and the bearing housing. The motor device according to claim 1 or claim 2.

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