JP2008155769A - In-wheel motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a dimension in the rotating shaft direction of an in-wheel motor. <P>SOLUTION: The in-wheel motor is provided with an axial motor 2 in which a rotor 20 and a stator 21 fixed inside a bottomed cylindrical wheel 1 are arranged in the rotating shaft direction to oppose to each other and with a drum-type braking device 3 for braking the rotation of the wheel 1. A brake shoe 31 constituting the braking device 3 is supported by the stator 21. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an in-wheel motor, and in particular, an axial motor having a stator and a rotor arranged opposite to each other in the rotation axis direction, and braking means for braking rotation of a bottomed cylindrical wheel having the rotor fixed inside. The present invention relates to an in-wheel motor provided.

  In recent years, electric vehicles driven by electric motors have been put into practical use. Patent Document 1 proposes an in-wheel motor in which an axial motor that rotates a wheel of an automobile is accommodated in the wheel (for example, Patent Document 1).

  FIG. 8 is a longitudinal sectional view schematically showing an example of the in-wheel motor. The in-wheel motor includes a bottomed cylindrical wheel 401 fitted with a tire 8, and the axial motor 2 and the braking device 403 are accommodated inside the wheel 401.

  The wheel 401 includes a disk portion 410 and a cylindrical portion 411 extending substantially perpendicularly from the periphery of the disk portion 410. A rotating shaft 23 protruding toward the vehicle body is provided at the center of the disk portion 410, and the rotating shaft 23 is rotatably supported via a bearing at a tip portion of an axle 404 protruding laterally outward from the vehicle body. ing.

  The axial motor 2 includes a rotor 20 and a stator 21 that are opposed to each other in the rotation axis direction. The rotor 20 is composed of permanent magnets 20 a equally arranged around the rotation shaft 23 of the disk portion 410. A disc-shaped stator 21 is extended radially outward at the tip of the axle 404 so that the rotor 20 and the stator 21 face each other in the rotational axis direction. The stator 21 has a magnetic core portion 21a provided around a disk-shaped stator substrate 22, and a coil 21b is wound around the magnetic core portion 21a.

  The braking device 403 includes a rotating body that rotates integrally with the wheel 401, and a brake element that contacts the rotating body and brakes the rotation of the wheel 401 with a frictional force. For example, the rotating body is a brake drum, and the brake is a brake shoe. A disc-shaped support body 436 is provided in the middle of the axle 404, and the brake is supported by the support body 436.

In the in-wheel motor configured as described above, the axial motor 2 that can be configured in a disk shape is adopted, so that the in-wheel motor can be arranged in the direction of the rotation axis as compared with a cylindrical inner rotor type or outer rotor type motor. The dimensions can be reduced.
JP-A-2005-341779

  However, since the axial motor 2 and the braking device 403 are configured separately and independently, there is a problem that components that can be shared such as the stator 21 and the support body 436 press the radial dimension of the in-wheel motor.

  The present invention has been made in view of such circumstances, and by supporting the brake element constituting the braking means on the stator of the axial motor, the axial motor and the component parts of the braking means are partially shared, and the direction of the rotation axis An object of the present invention is to provide an in-wheel motor capable of reducing the size of the in-wheel motor.

  Another object of the present invention is to provide an in-wheel motor capable of reducing the size in the radial direction or the axial direction by constituting the magnetic core of the stator with a dust magnetic material.

  Another object of the present invention is to provide an in-wheel motor capable of reducing the radial dimension by disposing a brake element in a portion where the torque contribution in the disk-shaped stator is small, that is, in the radial central portion of the stator. There is to do.

  Another object of the present invention is to prevent heat generated in the brake from being transmitted from the brake to the stator and changing the motor characteristics by interposing a heat insulating member between the brake and the stator. It is possible to provide an in-wheel motor capable of securing a more stable torque.

  An in-wheel motor according to a first aspect of the present invention includes an axial motor having a stator and a rotor arranged opposite to each other in the rotation axis direction, and braking means for braking rotation of a bottomed cylindrical wheel having the rotor fixed inside. In the in-wheel motor provided, the braking means is supported by a rotating body that rotates integrally with the wheel, and a stator of the axial motor, and a brake element that contacts the rotating body and brakes rotation of the wheel. It is characterized by providing.

In the first invention, the brake element constituting the braking means is supported by the stator constituting the axial motor, and the brake element contacts the rotating body that rotates integrally with the wheel to brake the rotation of the wheel. Is configured to do.
Therefore, a support for supporting the brake element is not necessary. That is, the axial dimension and the braking means are configured separately, and the radial dimension can be reduced as compared with a conventional in-wheel motor provided with a support that supports the brake element.

  The in-wheel motor according to a second aspect of the invention is characterized in that the stator includes a magnetic core made of a dust magnetic material.

  In the second invention, since the stator includes a magnetic core made of a dust magnetic material, eddy current loss can be effectively reduced. In addition, since the magnetic characteristics are isotropic, it is easy to form the magnetic core portion and the magnetic coupling of the axial motor can be efficiently formed as compared with the case where the stator is formed of laminated steel plates. As a result, the torque of the axial motor can be improved. In other words, the radial and axial dimensions, or the radial or axial dimensions of the axial motor can be reduced without reducing the torque of the axial motor.

  An in-wheel motor according to a third aspect of the present invention is characterized in that the stator has a disk shape and the brake element is disposed at a central portion in the radial direction of the stator.

In the third aspect of the invention, the brake element is disposed at the radial center of the disk-shaped stator. The contribution to the torque of the axial motor in the radial center portion of the stator, that is, the portion close to the rotating shaft is smaller than that in the radially outer portion.
The starter has a disk shape, but may have a hole or a notch in part. The central portion of the stator in the radial direction particularly indicates a portion where the stator magnetic core is not provided, for example, a radially inner portion of the annular surface of the stator substrate 322 as shown in FIG.
Therefore, by arranging the brake element in the central portion in the radial direction of the stator, the brake element can be arranged in the stator without reducing the torque of the axial motor and without increasing the radial dimension of the wheel.

  The in-wheel motor according to a fourth aspect is characterized in that a heat insulating member is interposed between the brake and the stator.

In the fourth aspect of the invention, since a heat insulating member is interposed between the stator and the brake, heat generated when the brake brakes the rotation of the wheel is conducted from the brake to the stator. Can be prevented. Therefore, the heat generated by the brake does not change the characteristics of the axial motor.
The starter has a disk shape, but may have a hole or a notch in part. The stator particularly indicates a portion where the magnetic core of the stator is not provided, for example, an annular surface of the stator substrate 22 shown in FIG. 1 and a portion where the magnetic core portion 21a is not provided.

  According to the present invention, by partially sharing the constituent members of the axial motor and the braking means, the dimension in the direction of the rotational axis is reduced as compared with the conventional in-wheel motor in which the axial motor and the braking means are separately configured. be able to.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
(Embodiment 1)
FIG. 1 is a longitudinal sectional view schematically showing an in-wheel motor according to Embodiment 1 of the present invention. The in-wheel motor according to the first embodiment of the present invention includes a bottomed cylindrical wheel 1 that can rotate with respect to an axle 4, an axial motor 2 that rotates the wheel 1, and a braking device 3 that brakes the rotation of the wheel 1. It has.

The axle 4 is configured to rotatably support, for example, a wheel 1 of a four-wheel automobile, and one end side is fixed to the vehicle body via a suspension so as to protrude laterally outward from the side portion of the vehicle body. Hereinafter, the one axle 4 and the in-wheel motor will be described. Also, directions such as the laterally outer side and the laterally inner side are directions based on the vehicle body.
On the other end side of the axle 4, a bearing seat 40 having a cylindrical diameter is formed. The outer ring of the plurality of bearings 5 is press-fitted into the inner surface of the bearing seat 40. One end side of a cylindrical rotary shaft 23 that rotatably supports the wheel 1 is press-fitted into the inner ring of the bearing 5.

  The wheel 1 has a disk part 10 having a hole formed in the center part, and a cylinder part 11 extending from the peripheral part of the disk part 10 to the vehicle body side. It is inserted through the hole of the disk part 10 and fastened with a nut 6. A wheel rim 12 to which the tire 8 is attached is welded to the outer peripheral surface of the cylindrical portion 11.

  The axial motor 2 is composed of a stator 21 and a rotor 20 that are arranged to face each other in the rotation axis direction.

  FIG. 2 is a schematic diagram showing the stator 21 when viewed from the outside of the vehicle side portion with the wheel 1 and the rotating shaft 23 removed. The stator 21 includes an annular stator substrate 22 that extends radially outward from the tip of the bearing seat 40. A fan-shaped magnetic core portion 21a is equally distributed in the circumferential direction on the laterally outer surface of the stator substrate 22, and a coil 21b is wound around the magnetic core portion 21a. The magnetic core portion 21a is made of a dust magnetic material, and the stator substrate 22 is made of a metal having a higher strength than the magnetic core portion 21a.

The magnetic core portion 21a includes a plurality of composite magnetic particles having metal magnetic particles and an insulating coating surrounding the surface of the metal magnetic particles. Note that the plurality of composite magnetic particles are bonded together by the engagement of the unevenness of the composite magnetic particles and the binding force of the binder.
The insulating coating functions as an insulating layer between the metal magnetic particles. By covering the metal magnetic particles with an insulating coating, the electrical resistivity of the magnetic core portion 21a obtained by pressure-molding this soft magnetic material can be increased. Thereby, it can suppress that an eddy current flows between metal magnetic particles, and can reduce the eddy current loss of the magnetic core part 21a. In addition, since the magnetic characteristics are isotropic, it is easier to form the magnetic core portion 21a and the magnetic coupling of the axial motor 2 can be efficiently formed as compared with the case where the stator 21 is formed of laminated steel plates. And the output of the axial motor 2 can be improved.

The average film thickness of the insulating coating is preferably 10 nm or more and 1 μm or less.
By setting the average thickness of the insulating coating to 10 nm or more, the tunnel current can be suppressed and the eddy current loss can be effectively suppressed. By setting the average thickness of the insulating coating to 1 μm or less, it is possible to prevent the insulating coating from being sheared and destroyed during pressure molding. In addition, since the ratio of the insulating film in the soft magnetic material does not become too large, it is possible to prevent the magnetic flux density of the magnetic core portion 21a obtained by pressing the soft magnetic material from being significantly reduced.

The insulating coating preferably has a single-layer or multi-layer structure using any one of a glass-based coating such as iron phosphate and manganese phosphate, a ceramic coating such as silica, and a resin coating such as silicon resin.
In addition, although the magnetic core part 21a formed by coating the metal magnetic particles with the insulating coating by mixing the metal magnetic particles and the insulating coating has been described, the magnetic core 21a is simply added to the metal magnetic particles with a resin, a lubricant, or the like. May be configured.

FIG. 3 is a schematic diagram showing the rotor 20 viewed from the vehicle body side.
The rotor 20 is composed of a plurality of fan-shaped permanent magnets 20 a equally arranged on the inner surface of the disk portion 10 so as to face the stator 21. Each permanent magnet 20a is magnetized so that the adjacent magnets have different polarities.

FIG. 4 is a schematic diagram showing the braking device 3 when viewed from the vehicle body side.
The braking device 3 is, for example, a leading trailing drum brake, and includes a brake drum 30 and a pair of brake shoes 31, 31 and the like.

  The brake drum 30 has a cylindrical shape having a dimension that can be fitted into the cylindrical portion 11 of the wheel 1, and an annular portion that follows the disk portion 10 extends radially inward at a peripheral edge on the outer side in the lateral direction. . Appropriate portions of the annular portion are fastened to the disk portion 10 of the wheel 1 with bolts 7.

  The brake shoes 31, 31 have a crescent shape following the inner peripheral surface of the brake drum 30. The ends of the brake shoes 31, 31 are rotatably supported by shoe pivots 32, 32 via a disk sheet-like heat insulating member 9 that insulates between the brake shoes 31, 31 and the stator substrate 22. ing. A shoe return spring (not shown) is hooked on the other end of each brake shoe 31, 31, and the shoe return spring is urged so that each brake shoe 31, 31 is separated from the brake drum 30. ing. On the surface of the stator 21 on the vehicle body side, a backward-acting wheel cylinder 33 that presses the brake shoes 31 in a direction in which the brake shoes 31 are brought into contact with the brake drum 30 is disposed.

  The wheel cylinder 33 is configured to expand and contract by hydraulic pressure, and an oil passage (not shown) that transmits the hydraulic pressure to the wheel cylinder 33 is connected to the wheel cylinder 33. The oil passage having one end connected to the wheel cylinder 33 is routed to the vehicle body side, and the other end of the oil passage is connected to the brake device.

  In the in-wheel motor configured as described above, a conventional in-wheel in which the axial motor 2 and the braking device 3 are configured separately by partially sharing the components of the axial motor 2 and the braking device 3. Compared with the motor, the dimension in the rotation axis direction can be reduced.

  Further, by configuring the magnetic core portion 21a of the stator 21 with a powder magnetic material, the radial and axial dimensions of the axial motor 2 or the radial or axial direction of the axial motor 2 can be reduced without reducing the torque of the axial motor 2. The dimensions can be reduced.

  Further, by interposing the heat insulating member 9 between the brake shoes 31, 31 and the stator substrate 22, the frictional heat generated in the brake shoes 31, 31 is conducted to the stator 21 and the characteristics of the axial motor 2 change. This can be prevented, and a more stable torque output can be secured.

  Furthermore, the stator substrate 22 is made of a material having a strength higher than that of the magnetic core portion 21a, whereby the stator 21 can be prevented from being damaged by a frictional force generated when braking the rotation of the wheel 1.

  In Embodiment 1, an in-wheel motor for a four-wheeled vehicle has been described. Needless to say, the present invention may be applied to an in-wheel motor for another vehicle such as a two-wheeled vehicle.

  Moreover, although it has comprised so that the rotating shaft which rotates with a wheel may be supported by an axle, if the wheel provided with the rotor rotates with respect to a stator, the structure of a bearing part may be another structure. good. For example, the wheel may be configured to be rotatably supported on the axle.

  Furthermore, although the disk-sheet-like heat insulating member has been described, other shapes may be used as long as heat can be prevented from being transmitted from the brake shoe to the stator.

  Furthermore, iron phosphate, silica, silicon resin, and the like have been described as the insulating coating for covering the metal magnetic particles constituting the dust magnetic body, but other materials as described later may be used.

  For example, the glass-based film is preferably made of a phosphoric acid compound, a silicon compound, a zirconium compound, or a boron compound. Specifically, it is preferably made of zinc phosphate, calcium phosphate, aluminum phosphate, phosphoric acid, silicon oxide, titanium oxide, zirconium oxide, or the like.

  The ceramic film preferably contains alumina, magnesia or the like.

  As the resin, an imide resin, a thermoplastic resin, a non-thermoplastic resin, or a higher fatty acid is preferably used. Specifically, thermoplastic resins such as thermoplastic polyimide, thermoplastic polyamide, thermoplastic polyamideimide, polyphenylene sulfide, polyethersulfone, polyetherimide or polyetheretherketone, high molecular weight polyethylene, wholly aromatic polyester, Non-thermoplastic resins such as aromatic polyimide and non-thermoplastic polyamideimide, and higher fatty acid salts such as zinc stearate, lithium stearate, calcium stearate, lithium palmitate, calcium palmitate, lithium oleate or calcium oleate It is preferred that Moreover, these organic substances can also be mixed and used. High molecular weight polyethylene refers to polyethylene having a molecular weight of 100,000 or more.

  The insulating film is made of metal oxide, metal nitride, metal oxide, phosphoric acid using Fe, Al, Ca, Mn, Zn, Mg, V, Cr, Y, Ba, Sr or rare earth elements as metals. It may consist of a metal salt compound, a borate metal salt compound, a silicate metal salt compound, or the like.

  The insulating coating is an amorphous compound of phosphate of at least one substance selected from the group consisting of Al, Si, Mg, Y, Ca, Zr, and Fe, and amorphous of borate of the substance It may consist of a compound.

  Furthermore, the insulating film may be made of an amorphous compound of an oxide of at least one substance selected from the group consisting of Al, Si, Mg, Y, Ca, and Zr.

  In addition, although it has shown about the case where the composite magnetic particle which comprises the magnetic core part 21a is comprised by the insulating film of 1 layer, the composite magnetic particle which comprises the magnetic core part 21a is formed by the insulating film of multiple layers so that it may mention below It may be configured.

  Specifically, for example, in the magnetic core portion 21a, the insulating coating may have one insulating coating and another insulating coating. One insulating film surrounds the surface of the metal magnetic particle, and the other insulating film surrounds the surface of the one insulating film. In this case, it is preferable to use a glass-based film or a ceramic film as one insulating film, and a resin film as the other insulating film.

(Embodiment 2)
FIG. 5 is a longitudinal sectional view schematically showing an in-wheel motor according to Embodiment 2 of the present invention. The in-wheel motor according to the second embodiment includes the axle 4, the rotary shaft 23, the wheel 201, the axial motor 2, and the like similar to the in-wheel motor according to the first embodiment. Since the in-wheel motor according to the second embodiment is different from the in-wheel motor according to the first embodiment only in the configuration of the braking device 203, the difference will be mainly described below.

  FIG. 6 is a schematic diagram showing the braking device 203 when viewed from the vehicle body side. The braking device 203 according to Embodiment 2 includes a brake disk 230 and a caliper 231.

  The brake disc 230 has an annular shape with an outer diameter that is substantially the same as the inner diameter of the wheel 201, and is fastened to the cylindrical portion 211 of the wheel 201 with a bolt 235.

  The caliper 231 includes a pad. The pad is a member that is disposed in a gap that is formed in the center of an annular brake disc 230 and that holds the brake disc open from the inside in the radial direction. The pad is supported on the stator substrate 22 so as to sandwich both annular surfaces of the brake disk 230. A heat insulating member 209 is interposed between the caliper 231 and the stator substrate 22.

  The caliper 231 is configured to sandwich the brake disc 230 with hydraulic pressure, and an oil passage (not shown) that transmits the hydraulic pressure to the caliper 231 is connected to the caliper 231.

  In the in-wheel motor according to the second embodiment, as in the first embodiment, the caliper 231 of the braking device 203 is provided on the stator 21 so that the dimension in the rotation axis direction is smaller than that of the conventional in-wheel motor. Can be configured.

  Other configurations, operations, and effects of the in-wheel motor according to the second embodiment are the same as the configurations, operations, and effects of the in-wheel motor according to the first embodiment. Therefore, detailed description is omitted.

(Embodiment 3)
FIG. 7 is a longitudinal sectional view schematically showing an in-wheel motor according to Embodiment 3 of the present invention. The in-wheel motor according to the third embodiment includes an axle 304, a rotating shaft 23, a wheel 301, an axial motor 302, and the like similar to the in-wheel motor according to the first embodiment. Since the in-wheel motor according to the third embodiment is different from the in-wheel motor according to the first embodiment only in the configuration of the braking device 303 and the axial motor 302, the difference will be mainly described below.

  The braking device 303 is a leading trailing drum brake, and includes a brake drum 330 and a set of brake shoes 331.

  The brake drum 330 has a cylindrical shape having an outer diameter dimension that does not interfere with the permanent magnet 320a of the rotor 320 and can be disposed at the center portion of the stator substrate 322, and is radially inward at a peripheral edge on one end side in the lateral direction. An annular portion is extended. Appropriate portions of the annular portion are fastened to the disk portion 310 of the wheel 301 by bolts 307.

  The brake shoe 331 has a crescent shape that follows the inner peripheral surface of the brake drum 330. The end of each brake shoe 331 is pivotally supported on the outer surface of the stator substrate 322 by a shoe pivot 332 via a heat insulating member 309 that insulates between the brake shoe 331 and the stator substrate 322. A shoe return spring is hooked on the other end of each brake shoe 331, and the shoe return spring is urged so that each brake shoe 331 is separated from the brake drum 330. A return-type wheel cylinder 333 is disposed on the laterally outer surface of the stator 321.

  The wheel cylinder 333 is configured to expand and contract by hydraulic pressure, and an oil passage (not shown) is connected to the wheel cylinder 333 in order to transmit the hydraulic pressure to the wheel cylinder 333.

  In the in-wheel motor according to the third embodiment, the braking device 303 is arranged in a portion where the torque contribution is small, that is, the central portion of the stator substrate 322, so that the torque of the axial motor 302 is not lowered and the wheel is reduced. The brake shoe 331 can be disposed on the stator 321 without increasing the radial dimension of 301.

  In the third embodiment, the drum brake type braking device is arranged at the central portion of the stator substrate. However, the disc brake type braking device is arranged at the central portion of the stator substrate. Also good. The above-described effects can be obtained even with a disc brake type braking device.

Other configurations, operations, and effects of the in-wheel motor according to the third embodiment are the same as the configurations, operations, and effects of the in-wheel motor according to the first embodiment. Therefore, detailed description is omitted.
Although the embodiments and examples of the present invention have been described above, the embodiments and examples of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these inventions. The present invention is not limited to the embodiment. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

It is a longitudinal cross-sectional view which shows typically the in-wheel motor which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows a stator at the time of seeing from the vehicle side part outer side in the state which removed the wheel and the rotating shaft. It is a schematic diagram which shows the rotor seen from the vehicle body side. It is a schematic diagram which shows the braking device when it sees from the vehicle body side. It is a longitudinal cross-sectional view which shows typically the in-wheel motor which concerns on Embodiment 2 of this invention. It is a schematic diagram which shows the braking device when it sees from the vehicle body side. It is a longitudinal cross-sectional view which shows typically the in-wheel motor which concerns on Embodiment 3 of this invention. It is a longitudinal section showing an example of an in-wheel motor typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel 2 Axial motor 3 Braking device 4 Axle 5 Bearing 9 Heat insulation member 10 Disk part 11 Tube part 12 Wheel rim 20 Rotor 21 Stator 21a Magnetic core part 21b Coil 22 Stator substrate 23 Rotating shaft 30 Brake drum 31 Brake shoe 32 Shoe pivot 33 Wheel Cylinder

Claims (4)

In an in-wheel motor comprising an axial motor formed by arranging a stator and a rotor so as to face each other in a rotation axis direction, and braking means for braking rotation of a bottomed cylindrical wheel with the rotor fixed inside.
The braking means includes
A rotating body that rotates integrally with the wheel;
An in-wheel motor comprising: a brake that is supported by a stator of the axial motor and that brakes rotation of the wheel in contact with the rotating body. The in-wheel motor according to claim 1, wherein the stator includes a magnetic core made of a dust magnetic material. The stator has a disk shape,
The in-wheel motor according to claim 1, wherein the brake element is disposed at a central portion in a radial direction of the stator. The in-wheel motor according to any one of claims 1 to 3, wherein a heat insulating member is interposed between the brake element and the stator.

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