In-wheel motor

Abstract

To provide an in-wheel motor in which demagnetization of a permanent magnet due to frictional heat of a brake using friction energy can be prevented.SOLUTION: An in-wheel motor 1 comprises: a first housing 2 which is unrotatably fixed to a vehicle body; a second housing 3 which rotates together with a wheel W; a friction brake FB which stops rotation of the second housing 3 by use of friction energy; a stator portion 6 around which a coil 6b is wound, and which is attached to the first housing 2; a rotor portion R which has a permanent magnet 8 so located as to face the stator portion 6, and which is provided in the second housing 3; and a magnetic brake MB which is provided on a radial opposite side to the permanent magnet 8 of the in-wheel motor 1 with the stator portion 6 interposed therebetween, and stops rotation of the second housing 3 by using magnetic energy.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an in-wheel motor. [Background technology]

[0002] Patent Document 1 discloses an in-wheel motor that includes a stator fixed to a non-rotating portion of a hub unit that rotatably supports a wheel on a vehicle body, an outer rotor fixed to a rotating portion of the hub unit and disposed on the outer periphery of the stator, and a brake disc fixed to the outer rotor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4730078 Summary of the Invention [Problem to be solved by the invention]

[0004] In the invention described in Patent Document 1, a permanent magnet is provided on an outer rotor, and this outer rotor is located near a brake disc. Frictional heat is generated in the brake disc when braking force is generated. The frictional heat generated in the brake disc reaches extremely high temperatures. If this high-temperature frictional heat is transmitted to the permanent magnet of the outer rotor, the permanent magnet may be demagnetized. If the permanent magnet is demagnetized in this way, the driving force of the in-wheel motor may be reduced.

[0005] The present invention has been made in consideration of these technical problems, and aims to provide an in-wheel motor that can prevent demagnetization of permanent magnets due to frictional heat of a brake that uses frictional energy. [Means for solving the problem]

[0006] According to one aspect of the present invention, an in-wheel motor includes a fixed housing portion fixed to a vehicle body so as not to rotate, a rotatable housing portion that rotates together with a wheel, a first brake that stops rotation of the rotatable housing portion by using frictional energy, a stator portion around which a motor coil is wound and attached to the fixed housing portion, a rotor portion provided in the rotatable housing portion and having a permanent magnet arranged to face the motor coil, and a second brake that is provided on the radially opposite side of the in-wheel motor from the permanent magnet with the stator portion in between and stops rotation of the rotatable housing portion by using magnetic energy. The second brake includes a magnetic fluid accommodated in a brake chamber formed in the fixed housing portion, a brake rotor provided in the rotating housing portion and penetrating into the magnetic fluid, and a brake coil that generates a magnetic flux that passes through the magnetic fluid. . According to another aspect of the present invention, an in-wheel motor includes a fixed housing part fixed to the vehicle body so as not to rotate, a rotating housing part rotating together with the wheel, a first brake that stops the rotation of the rotating housing part by using frictional energy, a stator part wound with a motor coil and attached to the fixed housing part, a rotor part provided in the rotating housing part and having a permanent magnet arranged to face the motor coil, and a second brake that is provided on the radially opposite side of the in-wheel motor from the permanent magnet across the stator part and stops the rotation of the rotating housing part by using magnetic energy, the second brake having a brake rotor provided in the rotating housing part and extending into a brake chamber formed in the fixed housing part, and a brake coil that cooperates with the brake rotor to generate eddy currents, and the brake coil and the motor coil are supplied with power from the same power source. According to another aspect of the present invention, an in-wheel motor includes a fixed housing part fixed to a vehicle body so as not to rotate, a rotating housing part that rotates together with the wheel, a first brake that stops the rotation of the rotating housing part by using frictional energy, a stator part around which a motor coil is wound and attached to the fixed housing part, a rotor part that has a permanent magnet arranged to face the motor coil and is provided in the rotating housing part, and a second brake that is provided on the radial opposite side of the in-wheel motor from the permanent magnet with the stator part in between and stops the rotation of the rotating housing part by using magnetic energy, wherein the rotor part is provided radially outside the stator part and the second brake is provided radially inside the stator part. . [Effects of the Invention]

[0007] In this embodiment, braking force can be generated not only by the first brake using frictional energy but also by the second brake using magnetic energy, so the amount of frictional heat generated by the first brake using frictional energy can be reduced, thereby preventing the permanent magnet from being demagnetized by the frictional heat generated by the first brake. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view of an in-wheel motor according to a first embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of an in-wheel motor according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] First Embodiment An in-wheel motor 1 according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view of the in-wheel motor 1 according to the first embodiment.

[0011] As shown in Fig. 1, the in-wheel motor 1 is provided so as to be located inside a wheel W on which a tire T of a vehicle is mounted. The in-wheel motor 1 includes a first housing 2 as a fixed housing portion and a second housing 3 as a rotating housing.

[0012] The first housing 2 is attached to a member that cannot rotate relative to the vehicle body, such as a suspension knuckle (not shown). The first housing 2 is formed in a substantially cylindrical shape from a non-magnetic material such as an aluminum alloy. A through hole 21 is provided in the center of the first housing 2, through which a hub 4 to which a wheel W is bolted is inserted. A plurality of bearings 5 ​​are provided between the through hole 21 and the hub 4. As a result, the wheel W bolted to the hub 4 is rotatably supported by the suspension (not shown) via the first housing 2.

[0013] A stator portion 6 is provided on the outer peripheral surface 22 of the first housing 2. The stator portion 6 has an annular stator core 6a provided on the outer peripheral surface 22 of the first housing 2, and a coil 6b wound around the stator core 6a as a motor coil.

[0014] The stator core 6a is made of a ferromagnetic material. The coils 6b function as a three-phase coil including a U-phase coil, a V-phase coil, and a W-phase coil. Power from a battery (not shown) installed in the vehicle is supplied to the coils 6b via an inverter unit (not shown).

[0015] A space S serving as an annular brake chamber is provided inside the first housing 2. A coil 7a formed in an annular shape as a brake coil and a core 7b provided to cover the coil 7a are provided in the space S.

[0016] The coil 7a is formed, for example, by a single coil wound in the circumferential direction of the first housing 2. However, this is not limiting, and the coil 7a may be a plurality of coils, or the coil 7a may be wound so as to generate a magnetic flux in the radial direction of the first housing 2. In other words, the coil 7a may have any shape as long as it can generate a predetermined magnetic field around it.

[0017] A magnetic fluid L is contained in a region of the annular space S radially inward of the coil 7a. The magnetic fluid L is a semi-fluid liquid in which ferromagnetic particles such as iron are dispersed in a liquid such as oil or grease. The role of the magnetic fluid L will be described later.

[0018] The second housing 3 is fixed to the hub 4 and rotates integrally with the hub 4. The second housing 3 is made of a non-magnetic material such as an aluminum alloy and has a generally cylindrical shape with one end closed. Specifically, the second housing 3 has a cylindrical portion 31 that accommodates the first housing 2 therein, a bottom portion 32 that closes the opening on one end of the cylindrical portion 31, a brake disc portion 33 that is formed on the outer periphery of the open end on the other end and extends radially outward in a flange-like shape, and a brake rotor 34 that protrudes from the bottom portion 32 toward the open side of the cylindrical portion 31 and enters the magnetic fluid L.

[0019] A plurality of permanent magnets 8 are provided on the inner circumferential wall of the cylindrical portion 31 of the second housing 3, aligned in the circumferential direction of the cylindrical portion 31. The permanent magnets 8 are provided facing the stator portion 6 with a small gap (air gap) between them. The permanent magnets 8, together with the cylindrical portion 31 of the second housing 3, form the rotor portion R of the in-wheel motor 1. In this embodiment, the stator portion 6 and the rotor portion R form the motor portion M.

[0020] A through hole 35 through which the hub 4 is inserted is provided in the center of the bottom portion 32 of the second housing 3.

[0021] The brake disc portion 33, together with a brake pad and a brake cylinder (not shown), constitutes a mechanical brake, a so-called disc brake.

[0022] The brake rotor 34 is formed in a cylindrical shape. The brake rotor 34 is formed from a separate member and then fixed to the bottom portion 32. The brake rotor 34 is formed, for example, from a ferromagnetic metal material. Note that only the portion of the brake rotor 34 that enters the magnetic fluid L may be made of a ferromagnetic material.

[0023] A seal member (not shown) is provided at the portion where the brake rotor 34 penetrates the first housing 2. This makes it possible to prevent the magnetic fluid L from leaking from the space S to the outside.

[0024] The hub 4 is formed into a hollow cylindrical shape from a metal material such as an aluminum alloy. A shaft 9 supported by the vehicle body is inserted into the inside of the hub 4. The hub 4 and the shaft 9 rotate together via a spline connection or the like.

[0025] The hub 4 has a flange 41 located between the bottom 32 of the second housing 3 and the wheel W. The wheel W is fastened to the flange 41 with bolts. This allows the tire T mounted on the wheel W to rotate integrally with the shaft 9. The shaft 9 is rotatably supported on the vehicle body.

[0026] The operation of the in-wheel motor 1 configured in this manner will be described.

[0027] In response to instructions from a controller (not shown), the in-wheel motor 1 uses a battery (not shown) as a power source and applies three-phase alternating current generated by an inverter unit (not shown) configured with a power module or the like to a coil 6b (motor section M), thereby generating driving force for driving the tire T. The in-wheel motor 1 also generates and regenerates electric power by rotating using the driving force from the tire T. The regenerated electric power is charged into the battery. When regenerating electric power, a braking force is generated on the tire T. Hereinafter, the brake using the braking force generated when the motor section M regenerates electric power is referred to as a regenerative brake RB.

[0028] When decelerating the vehicle, a regenerative brake RB by the motor unit M, a friction brake FB (mechanical brake) by the brake disc unit 33, and a magnetic brake MB by the magnetic fluid L described below are used. The braking force of these brakes is distributed based on a map that is determined in advance based on the relationship between the battery SOC, vehicle speed, brake pedal pressure, and the temperature of each brake. In this embodiment, the friction brake FB (mechanical brake) by the brake disc unit 33 corresponds to the first brake, and the magnetic brake MB by the magnetic fluid L corresponds to the second brake.

[0029] Next, the magnetic brake MB using the magnetic fluid L will be described.

[0030] When a current is applied to the coil 7a in response to a command from a controller (not shown), a magnetic field is generated around the coil 7a. The magnetic field generated around the coil 7a acts on the magnetic fluid L. As a result, the fine particles (magnetic particles) contained in the magnetic fluid L are arranged in a chain shape along the magnetic flux of the magnetic field generated by the coil 7a, more specifically, between the coil 7a and the brake rotor 34. When the brake rotor 34 rotates, shear stress acts on the fine particles (magnetic particles) arranged in a chain shape. This shear stress then functions as a braking force (magnetic brake MB) that decelerates the rotational speed of the brake rotor 34. The braking force generated by the magnetic brake MB is adjusted by controlling the voltage or current applied to the coil 7a.

[0031] When the friction brake FB is used frequently during deceleration of the vehicle, frictional heat can cause the brake disc portion 33 to become hot. If the heat generated in the brake disc portion 33 is transferred to the permanent magnet 8 through the cylindrical portion 31, the permanent magnet 8 may be demagnetized. If the permanent magnet 8 is demagnetized in this way, the driving force generated by the motor portion M will decrease.

[0032] Therefore, the in-wheel motor 1 of this embodiment is provided with a magnetic brake MB. With this configuration, braking force can be generated by the magnetic brake MB in addition to the friction brake FB, thereby suppressing the amount of frictional heat generated by the friction brake FB. This reduces the amount of frictional heat generated by the friction brake FB and transmitted to the permanent magnet 8. Furthermore, since the magnetic brake MB does not have any parts where metal comes into sliding contact with another metal, there is no risk of wear powder being generated, and since there is no wear on parts, it is possible to suppress the creation of additional burdens such as part replacement.

[0033] Furthermore, in the in-wheel motor 1 of this embodiment, the magnetic brake MB is provided on the radially opposite side of the in-wheel motor 1 from the permanent magnets 8, across the stator portion 6, i.e., the magnetic brake MB is provided radially inward of the stator portion 6. When braking force is generated in the magnetic brake MB, magnetic energy is converted into thermal energy, and heat is generated. For this reason, by providing the magnetic brake MB at a position separated from the permanent magnets 8, it is possible to minimize the transfer of heat generated in the magnetic brake MB to the permanent magnets 8.

[0034] Furthermore, with this configuration, friction brake FB and magnetic brake MB are located at a distance from each other. This increases the space (surface area) for dissipating the heat generated in friction brake FB and magnetic brake MB, allowing the heat generated in friction brake FB and magnetic brake MB to be dissipated before being transferred to permanent magnet 8.

[0035] Second Embodiment An in-wheel motor 101 according to the first embodiment will be described with reference to Fig. 2. Fig. 2 is a schematic cross-sectional view of the in-wheel motor 101 according to the second embodiment. The following description will focus on differences from the in-wheel motor 1 of the first embodiment, and the same components as those in the in-wheel motor 1 of the first embodiment will be given the same reference numerals and will not be described again.

[0036] The in-wheel motor 1 of the second embodiment differs from the in-wheel motor 1 in that the in-wheel motor 1 of the first embodiment is an outer rotor type in which the rotor portion R is arranged radially outside the stator portion 6, whereas the in-wheel motor 101 of the second embodiment is an inner rotor type in which the rotor portion R is arranged radially inside the stator portion 6, and that the in-wheel motor 1 of the first embodiment has the magnetic brake MB arranged radially inside the stator portion 6, whereas the in-wheel motor 101 of the second embodiment has the magnetic brake MB arranged radially inside the stator portion 6.

[0037] As shown in FIG. 2, the in-wheel motor 101 includes a first housing 102 as a fixed housing portion and a second housing 103 as a rotating housing.

[0038] The first housing 102 is attached to a member that cannot rotate relative to the vehicle body, such as a suspension knuckle (not shown). The first housing 102 is formed in a substantially cylindrical shape from a non-magnetic material such as an aluminum alloy. A recess 122 that opens to one end and accommodates the rotor portion R is provided in the center of the first housing 102. A through hole 121 is provided in the center of the first housing 102, through which a hub 4 to which a wheel W is bolted is inserted. A plurality of bearings 5 ​​are provided between the through hole 121 and the hub 4. As a result, the wheel W bolted to the hub 4 is rotatably supported by the suspension (not shown) via the first housing 102.

[0039] The stator portion 6 is provided in the recess 122 of the first housing 102. The stator portion 6 has a plurality of stator cores 6a arranged side by side in the circumferential direction on the inner circumferential surface of the recess 122 of the first housing 102, and coils 6b wound around the stator cores 6a as motor coils.

[0040] A space S serving as an annular brake chamber is provided radially outward of the recess 122 in the first housing 102. A coil 7a formed in an annular shape as a brake coil and a core 7b provided to cover the coil 7a are provided in the space S. The configuration within the space S (coil 7a, core 7b, and magnetic fluid L) is the same as in the first embodiment, and therefore description thereof will be omitted.

[0041] The second housing 103 is fixed to the hub 4 and rotates integrally with the hub 4. The second housing 103 is formed in a generally flat plate shape from a non-magnetic material such as an aluminum alloy. Specifically, the second housing 103 has a flat plate portion 131 fixed to the hub 4, a brake disc portion 133 extending radially outward from the outer edge of the flat plate portion 131 in a flange-like shape, and a brake rotor 134 formed to protrude from the flat plate portion 131 toward the first housing 102 and enter the magnetic fluid L.

[0042] A through-hole 135 through which the hub 4 is inserted is provided in the center of the flat plate portion 131 of the second housing 103.

[0043] The brake disc portion 133 constitutes a mechanical brake together with a brake pad and a brake cylinder (not shown).

[0044] The configuration of the brake rotor 134 is the same as that of the brake rotor 34 according to the first embodiment, and therefore a description thereof will be omitted.

[0045] The hub 4 is formed into a hollow cylindrical shape from a metal material such as an aluminum alloy. A shaft 9 supported by the vehicle body is inserted inside the hub 4. The hub 4 and shaft 9 rotate together via a spline connection or the like. A spacer 10 is attached to the outer circumferential surface of the hub 4. A plurality of permanent magnets 8 are provided on the outer circumferential surface of the spacer 10 so as to be aligned in the circumferential direction of the spacer 10. The permanent magnets 8 are provided so as to face the stator section 6 with a small gap (air gap) between them. The permanent magnets 8, together with the spacer 10, form the rotor section R of the in-wheel motor 1. In this embodiment, the spacer 10 also forms part of the rotating housing section. In this embodiment, the stator section 6 and the rotor section R also form the motor section M.

[0046] The operation of the in-wheel motor 101 is the same as that of the in-wheel motor 1 according to the first embodiment, and therefore a description thereof will be omitted.

[0047] The in-wheel motor 101 according to the second embodiment described above has the following advantages in addition to the advantages of the in-wheel motor 1 according to the first embodiment.

[0048] In the in-wheel motor 101, the permanent magnet 8 is provided radially inward of the stator portion 6, so the distance between the brake disc portion 133 and the permanent magnet 8 is longer than when the permanent magnet 8 is provided radially inward of the stator portion 6. This makes it possible to prevent frictional heat generated in the friction brake FB (brake disc portion 133) from being transmitted to the permanent magnet 8.

[0049] In the above embodiment, the second housing 103 and the spacer 10 are configured as separate members, but they may also be configured as an integrated unit.

[0050] Furthermore, the brake disc portion 133 may be provided at the same position (on the vehicle body side of the wheel W) as the brake disc portion 33 in the first embodiment.

[0051] In the first and second embodiments described above, a brake using a magnetic fluid L as the magnetic brake MB has been described as an example. However, this is not limiting. The magnetic brake MB may be configured such that an eddy current is generated in the brake rotor 34, 134 by the coil 7a, and a braking force is generated by this eddy current. In this case, the magnetic fluid L is not contained in the space S, and only the coil 7a and the core 7b are provided. In this configuration, by applying an alternating current to the coil 7a, an eddy current is generated in the brake rotor 34, 134 so as to prevent changes in the magnetic flux generated by the coil 7a. This eddy current can then generate a braking force that brakes the rotation of the brake rotor 34, 134.

[0052] Furthermore, in the first and second embodiments, the core 7b is provided, but the core 7b does not necessarily have to be provided.

[0053] In the first and second embodiments, the coil 7a and the core 7b are provided radially outward from the magnetic fluid L, but the coil 7a and the core 7b may also be provided radially inward from the magnetic fluid L. Also, in the first and second embodiments, the core may be provided radially inward from the region where the magnetic fluid L is provided. In this way, when a current is applied to the coil 7a, the fine particles (magnetic particles) of the magnetic fluid L are also arranged in a chain shape between the core and the brake rotor 34, 134, thereby increasing the braking force of the magnetic brake MB.

[0054] Furthermore, the shapes of the first housing 2, 102 and the second housing 3, 103 are not limited to those exemplified in the first and second embodiments, and may be any shape as long as it satisfies the spirit of the present invention.

[0055] The configuration, operation, and effects of the embodiment of the present invention configured as above will be described below.

[0056] The in-wheel motor 1,101 comprises a first housing 2,102 (fixed housing) fixed to the vehicle body so as not to rotate, a second housing 3,103 (rotating housing portion) that rotates together with the wheel W, a friction brake FB (first brake) that stops the rotation of the second housing 3,103 (rotating housing portion) using frictional energy, a stator portion 6 wound with a coil 6b (motor coil) and attached to the first housing 2,102 (fixed housing), a rotor portion R having a permanent magnet 8 arranged opposite the stator portion 6 and provided in the second housing 3,103 (rotating housing portion) or a spacer 10 (rotating housing portion), and a magnetic brake MB (second brake) that is arranged on the radially opposite side of the in-wheel motor 1 from the permanent magnet 8 across the stator portion 6 and stops the rotation of the second housing 3,103 (rotating housing portion) using magnetic energy.

[0057] In this configuration, braking force can be generated by magnetic brake MB (second brake) in addition to friction brake FB (first brake), so the braking force generated by friction brake FB (first brake) can be reduced. This makes it possible to suppress the amount of frictional heat generated in friction brake FB (first brake), so the amount of frictional heat generated by friction brake FB (first brake) and transmitted to permanent magnet 8 can be reduced. Therefore, it is possible to prevent permanent magnet 8 from being demagnetized by frictional heat generated by friction brake FB (first brake).

[0058] Furthermore, the magnetic brake MB (second brake) does not require hydraulic piping as in the case of a hydraulic brake, and therefore the structure can be simplified by adopting the above configuration.

[0059] In the in-wheel motor 1, 101, the second brake has a magnetic fluid L contained in a space S (brake chamber) formed in the first housing 2, 102 (fixed housing), a brake rotor 34, 134 provided in the second housing 3, 103 (rotating housing portion) and penetrating into the magnetic fluid L, and a coil 7a (brake coil) that generates a magnetic flux that passes through the magnetic fluid L.

[0060] In this configuration, the magnetic brake MB (second brake) does not have any areas where metal comes into sliding contact with another metal, so there is no risk of wear powder being generated, and since parts do not wear out, new burdens such as part replacement can be reduced.

[0061] In the in-wheel motor 1,101, the second brake is provided in the second housing 3,103 (rotating housing portion) and has a brake rotor 34,134 that penetrates into a space S (brake chamber) formed in the first housing 2,102 (fixed housing), and a brake coil that cooperates with the brake rotor 34,134 to generate an eddy current.

[0062] In this configuration, since the magnetic fluid L is not used, there is no need to provide a sealing member, etc. This simplifies the structure.

[0063] In the in-wheel motor 1, 101, the coil 7a (brake coil) and the coil 6b (motor coil) are supplied with power from the same power source.

[0064] In this configuration, the coil 7a (brake coil) and the coil 6b (motor coil) share a power source, which reduces the number of parts.

[0065] In the in-wheel motor 1, the rotor portion R is provided radially outside the stator portion 6, and the magnetic brake MB (second brake) is provided radially inside the stator portion 6.

[0066] In this configuration, the rotor section R is provided radially outside the stator section 6. This ensures a large space for arranging the permanent magnets 8, allowing the in-wheel motor 1 to have a large output.

[0067] In the in-wheel motor 101, the rotor portion R is provided on the radially inner side of the stator portion 6, and the magnetic brake MB (second brake) is provided on the radially outer side of the stator portion 6.

[0068] In this configuration, the permanent magnet 8 is provided radially inward of the stator portion 6, so the distance between the magnetic brake MB (second brake) and the permanent magnet 8 is longer than when the permanent magnet 8 is provided radially inward of the stator portion 6. This makes it possible to suppress the transmission of frictional heat generated in the friction brake FB (first brake) to the permanent magnet 8.

[0069] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. [Explanation of symbols]

[0070] 1,101···In-wheel motor, 2,102···First housing (fixed housing), 3,103···Second housing (rotating housing), 6···Stator portion, 6a···Stator core, 6b···Coil (motor coil), 7a···Coil (brake coil), 7b···Core, 8···Permanent magnet, 10···Spacer (rotating housing), 33,133···Brake disc portion, 34,134···Brake rotor

Claims

1. An in-wheel motor, a fixed housing portion fixed to the vehicle body so as not to be rotatable; a rotating housing portion that rotates together with the wheel; a first brake that stops rotation of the rotary housing portion by using frictional energy; a stator portion around which a motor coil is wound and attached to the fixed housing portion; a rotor portion provided in the rotary housing portion, the rotor portion having a permanent magnet arranged to face the motor coil; a second brake that is provided on the radially opposite side of the in-wheel motor from the permanent magnet with the stator portion interposed therebetween and that stops rotation of the rotatable housing portion by using magnetic energy, The second brake is a magnetic fluid accommodated in a brake chamber formed in the fixed housing portion; a brake rotor provided in the rotary housing portion and inserted into the magnetic fluid; a brake coil that generates a magnetic flux that passes through the magnetic fluid.

2. An in-wheel motor, a fixed housing portion fixed to the vehicle body so as not to be rotatable; a rotating housing portion that rotates together with the wheel; a first brake that stops rotation of the rotary housing portion by using frictional energy; a stator portion around which a motor coil is wound and attached to the fixed housing portion; a rotor portion provided in the rotary housing portion, the rotor portion having a permanent magnet arranged to face the motor coil; a second brake that is provided on the radially opposite side of the in-wheel motor from the permanent magnet with the stator portion interposed therebetween and that stops rotation of the rotatable housing portion by using magnetic energy, The second brake is a brake rotor provided in the rotary housing portion and inserted into a brake chamber formed in the fixed housing portion; a brake coil that cooperates with the brake rotor and generates eddy currents; In the in-wheel motor, the brake coil and the motor coil are supplied with power from the same power source.

3. An in-wheel motor, a fixed housing portion fixed to the vehicle body so as not to be rotatable; a rotating housing portion that rotates together with the wheel; a first brake that stops rotation of the rotary housing portion by using frictional energy; a stator portion around which a motor coil is wound and attached to the fixed housing portion; a rotor portion provided in the rotary housing portion, the rotor portion having a permanent magnet arranged to face the motor coil; a second brake that is provided on the radially opposite side of the in-wheel motor from the permanent magnet with the stator portion interposed therebetween and that stops rotation of the rotatable housing portion by using magnetic energy, the rotor portion is provided radially outward of the stator portion, The second brake is an in-wheel motor provided radially inside the stator portion.

4. 4. The in-wheel motor according to claim 3, The second brake is a brake rotor provided in the rotary housing portion and inserted into a brake chamber formed in the fixed housing portion; an in-wheel motor having a brake coil that cooperates with the brake rotor and generates an eddy current.

5. 5. The in-wheel motor according to claim 1, In the in-wheel motor, the brake coil and the motor coil are supplied with power from the same power source.

6. 3. The in-wheel motor according to claim 1 or 2, the rotor portion is provided radially outward of the stator portion, The second brake is an in-wheel motor provided radially inside the stator portion.

7. 3. The in-wheel motor according to claim 1 or 2, the rotor portion is provided radially inward of the stator portion, The second brake is an in-wheel motor provided radially outside the stator portion.

Images