JP6836974B2 - Wheel speed detector and in-wheel motor drive - Google Patents

Description

The present invention relates to a wheel speed detection device and an in-wheel motor drive device that detect the rotation of a wheel, and in particular, a wheel speed detection device for a wheel in which the in-wheel motor drive device is arranged inside, and an in-wheel equipped with the wheel speed detection device. Regarding motor drive device.

In recent years, in order to improve safety, the number of automobiles equipped with ABS (anti-lock braking system) is increasing. In ABS, a wheel speed detection device that detects the rotation of wheels is used. The wheel speed detection device includes a sensor target provided in a rotating portion that rotates integrally with the wheel, and a rotation sensor (wheel speed sensor) attached facing the sensor target. The detection signal of the rotation sensor is transmitted to a control device mounted on the vehicle body side, and the control device controls the brake mechanism such as adjustment of the brake oil pressure of the wheels. Such a rotation sensor is used not only for ABS but also for ESC (Electronic Stability Control).

As a device for detecting the rotation of a wheel in which an in-wheel motor drive device is arranged, it is disclosed in International Publication No. 2014/168032 (Patent Document 1) and JP-A-2016-169164 (Patent Document 2). As described above, a device for detecting the rotation of the wheel hub of the in-wheel motor drive device is known. Patent Document 1 proposes a technique in which a rotation sensor (sensing component) is attached so as to penetrate the upper part of an axle case, and a component to be sensed as a sensor target is press-fitted and fixed to an inner space of a wheel hub. .. Patent Document 2 proposes a technique in which an outer peripheral surface of a hub flange of an in-wheel motor drive device is used as a detected surface (sensor target).

International Publication No. 2014/168032 Japanese Unexamined Patent Publication No. 2016-109164

To avoid interference between the in-wheel motor drive and the inner wall of the wheel house formed on the outer side of the vehicle body in the vehicle width direction without sacrificing the interior space, shorten the axle length of the in-wheel motor drive. There is a need to. In addition, when the in-wheel motor drive is mounted on the steered wheels, the axle length of the in-wheel motor drive is longer than when mounted on the non-steering wheels in order to arrange the device without sacrificing the steered angle. We need to make it even shorter.

In the wheel speed detection device disclosed in Patent Document 1, the sensing component is press-fitted and fixed to the wheel hub from the inside in the vehicle width direction, and the rotation sensor is arranged on the radial outside of the sensing component. In this case, since the arrangement of the reduction mechanism is limited, the axial dimension of the in-wheel motor drive device becomes large. Therefore, in the technique of Patent Document 1, there is a possibility that interference with the inner wall of the wheel house or the suspension component may occur.

On the other hand, in the wheel speed detection device disclosed in Patent Document 2, since the outer peripheral surface of the hub flange is the surface to be detected (sensor target), the expansion of the axial dimension can be suppressed. However, since the hub flange is attached to the inner surface of the hat portion of the brake disc (the surface facing inward in the vehicle width direction), if the rotation sensor is arranged so as to face the outer peripheral surface of the hub flange, the radial dimension of the hat portion is obtained. Must be expanded. In this case, since the brake disc (brake rotor) itself has a large diameter, there may be a problem that the ride quality and running performance of the vehicle deteriorate due to the increase in unsprung weight.

The present invention has been made to solve the above problems, and an object of the present invention is to prevent expansion of the axial dimension of the in-wheel motor drive device and the radial dimension of the brake rotor. It is to provide a possible wheel speed detection device and an in-wheel motor drive device.

A wheel speed detection device according to a certain aspect of the present invention is a wheel speed detection device in which an in-wheel motor drive device detects the rotation of a wheel arranged inside. The in-wheel motor drive device includes an electric motor that drives the wheels, a speed reducer that decelerates and outputs the rotation of the electric motor, a wheel hub bearing that transmits the output of the speed reducer to the wheels, and a casing that houses the speed reducer. The wheel hub bearing portion includes a wheel hub that is coaxially coupled to a brake rotor having a hat portion formed so as to be recessed outward in the vehicle width direction. This wheel speed detection device forms a detected portion that causes a magnetic flux change in the circumferential direction on the surface of the hat portion that faces inward in the vehicle width direction, and reads the magnetic flux change of the detected portion to rotate the brake rotor. It is characterized by providing a rotation sensor for detection.

Preferably, the hat portion has an inner surface on which the flange portion of the wheel hub is fixed in a contact state, and the detected portion is formed at a position radially outside the flange portion and overlapping the flange portion in the axial direction. Has been done.

Preferably, the detected portion is formed on the inner surface of the hat portion.

In this case, the brake rotor is a separate body from the first member having the inner side surface of the hat portion and the first member, and is located inside the first member in the vehicle width direction and is located on the outer peripheral portion of the first member. It may include a second member which is connected.

Alternatively, the brake rotor is a separate body from the first member having the inner side surface of the hat portion and the first member, and is located inside the first member in the vehicle width direction and is located at the radial outer end of the first member. When the second member connected to the portion is included, the detected portion may be composed of an annular member that is co-tightened between the first member and the second member.

Preferably, the rotation sensor is attached to the casing of the in-wheel motor drive or a knuckle fixed to the casing.

An in-wheel motor drive device according to another aspect of the present invention is characterized by incorporating the above-mentioned wheel speed detection device.

According to the present invention, it is possible to prevent the axial dimension of the in-wheel motor drive device and the radial dimension of the brake rotor from being expanded. Therefore, it is possible to prevent the in-wheel motor drive device from interfering with the inner wall or the suspension component of the wheel house, and to reduce the unsprung weight. As a result, the ride quality and running performance of the vehicle can be improved.

It is a developed sectional view schematically showing a basic configuration example of an in-wheel motor drive device and its peripheral structure according to each embodiment of the present invention. It is sectional drawing which shows typically the wheel speed detection apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing which shows typically the wheel speed detection apparatus which concerns on Embodiment 2 of this invention. FIG. 2 is a perspective view of the brake disc as viewed from the inside in the vehicle width direction in the second embodiment of the present invention. FIG. 2 is a perspective view of the brake disc as viewed from the outside in the vehicle width direction in the second embodiment of the present invention. It is sectional drawing which shows typically the wheel speed detection apparatus which concerns on Embodiment 3 of this invention. FIG. 3 is a perspective view of the brake disc as viewed from the inside in the vehicle width direction in the third embodiment of the present invention.

Embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

<Embodiment 1>
The wheel speed detection device according to the present embodiment detects the rotation of the wheel on which the in-wheel motor drive device is arranged inside. The wheels are the wheels of a passenger vehicle such as an electric vehicle or a hybrid vehicle.

(About the basic configuration example of the in-wheel drive device)
First, a basic configuration example of the in-wheel motor drive device 1 and its peripheral structure will be described with reference to FIG. The in-wheel motor drive device 1 decelerates the rotation of the wheel hub bearing portion 11 provided in the center of the wheel, the motor portion 21 for rotationally driving the motor shaft 22, and the motor shaft 22 and transmits the rotation to the wheel hub bearing portion 11. A speed reducing unit 31 is provided. The speed reducer constituting the speed reduction unit 31 is, for example, a three-shaft parallel shaft gear speed reducer. The motor section 21 and the reduction section 31 are arranged offset from the axis O of the wheel hub bearing section 11. The axis O extends in the vehicle width direction and coincides with the axle direction.

The wheel hub bearing portion 11, the speed reduction portion 31, and the motor portion 21 are housed inside the wheel (inner air region), that is, inside the wheel wheel W. At least a part of the motor unit 21 may be arranged inside the wheel wheel W in the vehicle width direction in order to avoid interference with the wheels. The in-wheel motor drive device 1 is connected to the wheel wheel W to drive the wheels. The wheel is composed of a wheel wheel W and a tire fitted on the outer circumference thereof. In the following description, one of the axes in the O direction means the outside in the vehicle width direction, and the other in the axis O direction means the inside in the vehicle width direction.

The motor housing 20 that forms the outer shell of the motor portion 21, and the speed reducer housing 30 that forms the outer shell of the reduction gear portion 31 and the wheel hub bearing portion 11 constitute a casing 10 of the entire in-wheel motor drive device 1.

The wheel hub bearing portion 11 has an inner ring 12 which is a rotating element, an outer ring 13 which is a fixing element, and a plurality of rolling elements 14 arranged in an annular gap between the inner and outer rings. The outer ring 13 may be configured to include an outer ring cylinder member 13b and an outer ring attachment member 13c. The outer ring cylinder member 13b is press-fitted and fixed in the through hole of the outer ring attachment member 13c, and the outer ring attachment member 13c functions as an outer ring flange.

A protrusion 13f projecting to the outer diameter side is formed at one end of the outer ring cylinder member 13b in the axis O direction. The protrusion 13f regulates the relative movement of the outer ring attachment member 13c in one direction of the axis O. A circumferential groove extending in the circumferential direction is formed on the outer peripheral surface of the outer ring cylinder member 13b on the other side in the axis O direction, and a C-shaped snap ring 13r is fitted into the circumferential groove. As a result, the outer ring attachment member 13c is sandwiched between both the protrusion 13f and the snap ring 13r, and movement in the axis O direction is prohibited.

A plurality of female and female screw holes and through holes are bored in the outer ring attachment member 13c as the outer ring flange at intervals in the circumferential direction. For example, female female screw holes and through holes are alternately installed at predetermined intervals in the circumferential direction. Each female screw hole and each through hole extend parallel to the axis O, and bolts 83 and 84 are passed from one side in the axis O direction, respectively. The shaft portion of each bolt 83 penetrates the through hole of the knuckle 18 and is screwed into the female screw hole of the outer ring attachment member 13c. The head 83a of each bolt 83 projects from the knuckle 18 in one direction in the O-axis direction.

The outer edge of the outer ring attachment member 13c is formed with notches 13g and 13j having a predetermined shape for receiving and engaging the knuckle 18. The notch 13g is formed on one end face in the axial direction of the outer ring attachment member 13c. The above-mentioned female-female screw hole is formed inside the notch 13 g and points in one direction of the axis O. As a result, the outer ring 13 is attached and fixed to the knuckle 18.

The front wall portion 30f of the speed reducer housing 30 comes into surface contact with the other end surface of the outer ring attachment member 13c in the axis O direction. At the center of the outer ring attachment member 13c, a cylindrical tubular portion 13e that protrudes in the other direction in the axis O direction is formed, and this tubular portion 13e is inserted into an opening formed in the front wall portion 30f on the outer peripheral surface. And fit.

The above-mentioned through hole is formed inside the notch 13j formed on the outer edge of the outer ring attachment member 13c and extends in the axis O direction. The shaft portion of each bolt 84 penetrates the through hole and is screwed into the female screw hole formed in the front wall portion 30f of the speed reducer housing 30. As a result, the outer ring 13 is attached and fixed to the casing 10. The head of each bolt 84 is located inside the notch 13j. Further, the casing 10 is supported by the knuckle 18 via the outer ring 13.

The inner ring 12 is a tubular body longer than the outer ring 13, and is passed through the central hole of the outer ring 13. A flange portion 12f is formed at one end of the inner ring 12 protruding outward in the vehicle width direction from the outer ring 13 in the axis O direction. The flange portion 12f functions as a coupling portion and is coaxially coupled to the brake disc 5 and the wheel wheel W. The inner ring 12 is connected to the wheel by the wheel bolt 82 and rotates integrally with the wheel as a wheel hub. The wheel bolt 82 is passed through the through hole of the flange portion 12f from the other side in the axis O direction.

The brake disc 5 has a rotor portion 51 sandwiched between brake pads 80 supported by the brake caliper 81, and a hat portion 52 formed so as to be recessed outward in the vehicle width direction from the inner diameter side end portion of the rotor portion 51. ing. The rotor portion 51 and the hat portion 52 are integrally formed.

As shown in FIG. 2, the hat portion 52 includes a bottom wall portion 53 extending in the radial direction and an outer peripheral portion 54 connected to the outer peripheral edge portion of the bottom wall portion 53 and having a cylindrical inner diameter surface. Will be done.

The bottom wall portion 53 has an outer surface 53o facing outward in the vehicle width direction and an inner side surface 53i facing inward in the vehicle width direction. The outer side surface 53o and the inner side surface 53i are planes orthogonal to the axis O direction. The wheel wheel W comes into surface contact with the outer side surface 53o, and the flange portion 12f of the inner ring 12 comes into surface contact with the inner side surface 53i. The central hole portion 53a of the bottom wall portion 53 of the hat portion 52 fits with the inner ring 12 as a wheel hub. The bottom wall portion 53 is provided with a plurality of through holes 53b, and the wheel bolt 82 described above penetrates the through hole provided in the flange portion 12f of the inner ring 12 and the through hole 53b.

The center line of the outer peripheral portion 54 coincides with the axis O, and is connected to the radial inner end portion of the rotor portion 51 at the other end portion of the outer peripheral portion 54 in the axis O direction. The rotor portion 51 also has an outer surface 51o that is orthogonal to the axis O direction and faces outward in the vehicle width direction and an inner side surface 51i that faces inward in the vehicle width direction.

The motor unit 21 has a motor shaft (motor rotation shaft) 22, a rotor 23, a stator 24, and the motor housing 20 described above, and is sequentially arranged from the axis M of the motor unit 21 to the outer diameter side in this order. The motor unit 21 is an inner rotor and outer stator type radial gap motor, but other types may be used. For example, although not shown, the motor unit 21 may have an axial gap.

The axis M, which is the center of rotation of the motor shaft 22 and the rotor 23, extends parallel to the axis O away from the axis O of the wheel hub bearing portion 11 in the vehicle front-rear direction. That is, the motor portion 21 is offset from the axis O of the wheel hub bearing portion 11 so as to be separated from the front of the vehicle, for example.

Both ends of the motor shaft 22 are rotatably supported by the motor housing 20 via rolling bearings 27 and 28. A protruding portion 22p is formed at one end of the motor shaft 22 in the axis O direction. The protruding portion 22p extends along the axis M and is inserted into the central hole 32h of the shaft portion 32s of the deceleration portion 31.

The reduction gear 31 is a three-axis parallel shaft gear reducer, and is an output gear 36 coaxially coupled to the inner ring 12, an input gear 32 coaxially coupled to the motor shaft 22 of the motor portion 21, and an input gear. It has a plurality of intermediate gears 33 and 35 for transmitting rotation from 32 to the output gear 36, and the speed reducer housing 30 described above.

The input gear 32 is a small-diameter external gear, and is a large number of teeth formed on the outer periphery of the other end in the axial direction of the shaft portion 32s arranged along the axis M. The axis of the shaft portion 32s coincides with the axis M. By inserting the protruding portion 22p of the motor shaft 22 into the central hole 32h of the shaft portion 32s, the shaft portion 32s fits with the motor shaft 22 so as not to rotate relative to the motor shaft 22.

The shaft portion 32s is rotatably supported by the speed reducer housing 30 on both ends of the input gear 32 via rolling bearings 32m and 32n. The small-diameter input gear 32 meshes with the first intermediate gear 33, which is a large-diameter external gear. The intermediate gear 33 is coaxially coupled to the second intermediate gear 35 which becomes a small-diameter external gear by the intermediate shaft 34. Both ends of the intermediate shaft 34 are rotatably supported by the speed reducer housing 30 via rolling bearings 34m and 34n.

The axis R passing through the center of the intermediate shaft 34 extends parallel to the axis O of the wheel hub bearing portion 11 and is located between the axis O and the axis M in the vehicle front-rear direction. In this way, the deceleration unit 31 is arranged offset from the wheel hub bearing unit 11. The axis R of the speed reduction unit 31 is arranged above the axis O.

The small-diameter second intermediate gear 35 meshes with the large-diameter output gear 36. The output gear 36 is an external gear provided coaxially with the output shaft 15. The output shaft 15 is rotatably supported by the front wall portion 30f of the speed reducer housing 30 via a rolling bearing 36 m on the other hand in the O direction of the axis line than the output gear 36. Further, the output shaft 15 is rotatably supported by the back wall portion 30b of the speed reducer housing 30 via a rolling bearing 36n on the other side of the output gear 36 in the O-axis direction.

As described above, when the outer ring 13 is not an integral body including a flange as in the conventional case, but is attached and fixed to the outer periphery of the outer ring cylinder member 13b as an outer ring attachment member 13c which is a member different from the outer ring cylinder member 13b, the outer ring attachment member. The shape of 13c can be freely created. Therefore, the degree of freedom in layout of the outer ring attachment member seat (female female screw hole, through hole, notch 13g, 13j) is increased, and the conventional bolt space is eliminated and the axis O direction dimension of the in-wheel motor drive device 1 is eliminated. Can be made smaller than before.

Further, the outer ring attachment member seat portion (female female screw hole, through hole, notch 13g, 13j) of the outer ring attachment member 13c is provided on the outer diameter side of the flange portion 12f (inner ring seat portion) of the inner ring 12. This eliminates the need to secure a bolt space for receiving the bolts 83 and 84 between the flange portion 12f of the inner ring 12 and the outer ring attachment member 13c. Therefore, the flange portion 12f of the inner ring 12 is arranged so as to be closer to the outer ring attachment member 13c than before, the protruding length of the inner ring 12 protruding from the outer ring 13 is shortened, and the in-wheel motor drive device is smaller than the conventional one. 1 can be provided.

In the present embodiment, the outer ring 13 is divided into the outer ring cylinder member 13b and the outer ring attachment member 13c, but it may be an integral body including a flange like a general outer ring. Further, the wheel hub bearing portion 11 may be an inner ring fixed or outer ring rotating type. Further, in the present embodiment, an example is shown in which the speed reduction unit 31 is a parallel 3-axis gear reducer having axes O, R, and M extending in parallel with each other, but the configuration of the speed reduction unit 31 is not limited. For example, it may be applied to a planetary gear type speed reducer or a cycloid type speed reducer.

The wheel speed detection device 6 according to the present embodiment detects the speed of the wheel by detecting the rotation of the brake disc 5 coaxially coupled to the inner ring 12 as the wheel hub.

(About the arrangement example and the configuration example of the wheel speed detection device)
The wheel speed detection device 6 according to the present embodiment will be described with reference to FIG. FIG. 2 is a cross-sectional view schematically showing the wheel speed detection device 6 according to the first embodiment of the present invention.

The wheel speed detection device 6 includes a detected portion 61 provided in the rotating portion and causing a magnetic flux change in the circumferential direction, and a rotation sensor 62 provided in the fixed portion. The detected portion 61 is provided on the surface of the hat portion 52 of the brake disc 5 facing inward in the vehicle width direction. Specifically, it is desirable that the detected portion 61 is formed at a position radially outside the flange portion 12f of the inner ring 12 and overlapping the flange portion 12f in the axial direction (axial direction). The “inside the hat portion 52” represents a region surrounded by the bottom wall portion 53 and the outer peripheral portion 54 of the hat portion 52, that is, the internal space 520 of the hat portion 52.

In the present embodiment, the inner side surface 53i of the hat portion 52 itself is provided with irregularities at a constant pitch along the circumferential direction, whereby the detected portion 61 is formed. That is, the wheel speed detection device 6 according to the present embodiment includes the brake disc 5 as a configuration. In the present embodiment, the brake disc 5 is shown as the disc type brake rotor, but a drum type brake rotor may be used. That is, the detected portion 61 may be provided in the hat portion of the brake rotor.

FIG. 2 shows an example in which the detected portion 61 is formed by providing the hat portion 52 with convex portions at a constant pitch, but the detection is not limited, and the hat portion 52 is provided with concave portions at a constant pitch. The detected portion 61 may be formed. Further, a recessed portion may be provided on the inner side surface 53i of the hat portion 52, and the flange portion 12f of the inner ring 12 may be fitted into the recessed portion.

The rotation sensor 62 is arranged so as to face the detected unit 61, and detects the rotation of the brake disc 5 by reading the change in the magnetic flux of the detected unit 61. In the present embodiment, the rotation sensor 62 is attached to a knuckle 18 fixed to a casing 10 of the in-wheel motor drive device 1. When the brake disc 5 rotates, the rotation sensor 62 outputs an electromotive force that changes according to the unevenness of the detected portion 61 as a voltage. The detection signal of the rotation sensor 62 is transmitted to a control device provided on the vehicle body side. The rotation sensor 62 may be directly fixed to the casing 10.

It is desirable that at least the tip portion 62a of the rotation sensor 62 is arranged in the internal space 520 of the hat portion 52 of the brake disc 5. The tip portion 62a is a sensing portion that detects the unevenness of the detected portion 61. It is desirable that the tip portion 62a of the rotation sensor 62 is also formed at a position radially outside the flange portion 12f of the inner ring 12 and overlapping the flange portion 12f in the axial direction (axial direction).

As shown in FIG. 2, the head 83a of the bolt 83 for fixing the knuckle 18 is located in the internal space 520 of the hat portion 52. Specifically, the head 83a of the bolt 83 is located radially outside the flange portion 12f of the inner ring 12, and at least partially overlaps the head 82a of the wheel bolt 82 in the axis O direction.

It is desirable that the rotation sensor 62 is mounted at a circumferential position different from the circumferential position of the through hole of the knuckle 18 through which the bolt 83 is passed. As a result, the detected portion 61 can be formed at a position overlapping at least a part of the head 83a of the bolt 83 when viewed from one side in the axis O direction (outside in the vehicle width direction).

As described above, according to the present embodiment, since the wheel speed is detected by using the brake disc 5, it is not necessary to increase the axial dimension of the in-wheel motor drive device 1. Further, since the detected portion 61 is provided on the inner side surface 53i of the hat portion 52 of the brake disc 5, it is not necessary to separately provide a pulsar ring. Therefore, the number of parts can be reduced, and the assembly of the wheel speed detection device 6 can be simplified.

Further, since the rotation sensor 62 can be arranged along the axis O direction, it is not necessary to enlarge the outer diameter dimension L1 of the hat portion 52 of the brake disc 5 for the arrangement of the rotation sensor 62. Therefore, it is possible to arrange the wheel speed detection device 6 without enlarging the radial dimension and the axial dimension of the brake disc 5. As a result, it is not necessary to mount wheels larger than the required performance on the vehicle body, so that it is possible to prevent deterioration of the ride quality and running performance of the vehicle due to an increase in unsprung weight.

Further, since the inner side surface 53i of the hat portion 52 of the brake disc 5 is provided with irregularities as the detected portion 61, the surface area of the brake disc 5 can be increased. Therefore, it is possible to improve the heat dissipation performance of the brake disc 5 and prevent thermal distortion. Further, as the heat dissipation performance is improved, heat transfer from the brake disc 5 to the wheel hub (inner ring 12) can be suppressed, and damage to the wheel hub can be prevented.

Further, since the uneven shape of the detected portion 61 can also serve as a rib, the strength of the hat portion 52 can be improved. Further, as the strength is improved, the thickness of the bottom wall portion 53 of the hat portion 52 can be reduced, so that the weight of the brake disc 5 can be reduced. In addition, it is possible to prevent thermal distortion of the hat portion 52 as the strength is improved.

Further, since the detected portion 61 of the wheel speed detection device 6 is arranged at a position away from the rotor portion 51, it is possible to reduce the influence of the temperature rise due to the friction between the rotor portion 51 and the brake pad 80. Therefore, it is possible to prevent a detection failure due to thermal strain of the detected portion 61.

Further, since the wheel speed detection device 6 is arranged in the hat portion 52, it is possible to prevent a detection failure due to adhesion of mud, snow, brake dust, and the like.

It is also possible to provide an in-wheel motor drive device equipped with the wheel speed detection device 6.

<Embodiment 2>
The wheel speed detection device 6A according to the second embodiment will be described with reference to FIGS. 3 to 5. The basic configuration of the wheel speed detection device 6A and its peripheral structure are the same as those in the first embodiment. Therefore, only the part different from the first embodiment will be described below.

FIG. 3 is a cross-sectional view schematically showing the wheel speed detection device 6A according to the second embodiment of the present invention. The wheel speed detection device 6A includes a brake disc 5A instead of the brake disc 5 shown in the first embodiment. FIG. 4 shows a perspective view of the brake disc 5A viewed from the inside in the vehicle width direction, and FIG. 5 shows a perspective view of the brake disc 5A viewed from the outside in the vehicle width direction.

Similar to the first embodiment, the detected portion 61 is provided on the inner surface 53i itself of the hat portion 52 of the brake disc 5A, but in the present embodiment, the brake disc 5A is composed of two parts. That is, the brake disc 5A is composed of the first member 71 and the second member 72.

The first member 71 mainly constitutes the bottom wall portion 53 of the hat portion 52, and the second member 72 mainly constitutes the rotor portion 51. That is, the first member 71 is a disk-shaped member having an inner side surface 53i on which the detected portion 61 is formed. The second member 72 is an annular member that is separate from the first member 71, is located inside the first member 71 in the vehicle width direction, and is connected to the radial outer edge of the first member 71. .. The outer peripheral portion 54 of the hat portion 52 is composed of a radial outer end portion of the first member 71 and a radial inner end portion of the second member 72.

Specifically, at the radial outer end of the first member 71, an annular flange-shaped connecting portion 73 that protrudes radially outward at a position inside the vehicle width direction from the position of the inner side surface 53i is provided. Has been done. A plurality of projecting portions 74 projecting inward in the radial direction are provided at regular intervals along the circumferential direction at the radial inner end portion of the second member 72. The plurality of projecting portions 74 are provided at positions that overlap with the connecting portion 73 when viewed in the axis O direction.

The protruding portion 74 has a female screw hole 74a penetrating in the axis O direction. The connecting portion 73 has a plurality of through holes 73a provided at positions facing each of the plurality of female screw holes 74a. With the connecting portion 73 and the plurality of protruding portions 74 overlapped, the fastening bolt 76 inserted from the outside in the vehicle width direction is passed through the through hole 73a and the female screw hole 74a and screwed into the female screw hole 74a. As a result, the first member 71 and the second member 72 are connected. A washer 75 may be interposed between the connecting portion 73 and the plurality of protruding portions 74, for example.

As described above, according to the present embodiment, the first member 71 on which the detected portion 61 is formed is separated from the second member 72 that mainly constitutes the rotor portion 51, thereby forming the hat portion 52. It is possible to facilitate the processing of the detected portion 61 on the inner side surface 53i. Further, since the brake disc 5A has such a two-piece structure, heat transfer from the rotor portion 51 to the bottom wall portion 53 of the hat portion 52 can be prevented, so that the wheel speed detection accuracy can be improved. Can be done.

Further, if the wheel speed detection failure occurs due to the thermal strain of the bottom wall portion 53 of the hat portion 52, only the first member 71 needs to be replaced. On the contrary, when the rotor portion 51 is damaged, only the second member 72 needs to be replaced. Therefore, in any case, the repair cost can be suppressed.

<Embodiment 3>
The wheel speed detection device 6B according to the third embodiment will be described with reference to FIGS. 6 to 7. The basic configuration of the wheel speed detection device 6B and its peripheral structure are the same as those in the second embodiment. Therefore, only the part different from the second embodiment will be described below.

FIG. 6 is a cross-sectional view schematically showing the wheel speed detection device 6B according to the third embodiment of the present invention. The wheel speed detection device 6B includes a brake disc 5B instead of the brake disc 5A shown in the second embodiment. FIG. 7 shows a perspective view of the brake disc 5B as viewed from the inside in the vehicle width direction.

The brake disc 5B includes the first member 71 and the second member 72 as in the second embodiment, but the detected portion 61 is not provided on the first member 71. The detected portion 61 is composed of an annular member, that is, a pulsar ring 77, which is fastened together between the first member 71 and the second member 72. A large number of holes 77a are formed in the pulsar ring 77 at a constant pitch along the circumferential direction.

A plurality of through holes 77a through which the fastening bolt 76 penetrates are provided on the outer peripheral edge of the pulsar ring 77. Thereby, the fastening bolt 76 can hold the outer peripheral edge portion of the pulsar ring 77 between the connecting portion 73 and the plurality of protruding portions 74. In the present embodiment, the pulsar ring 77 is arranged at a distance from the inner side surface 53i of the hat portion 52.

Even when the pulsar ring 77 having the detected portion 61 is separately provided as in the present embodiment, the pulsar ring 77 is radially outside the flange portion 12f of the inner ring 12 and in the flange portion 12f and the axis O direction. It is desirable that they are formed at positions that overlap (in the axial direction). By doing so, also in the present embodiment, since the tip portion 62a of the rotation sensor 62 can be arranged in the hat portion 52, it is possible to prevent the brake disc 5B from expanding in the axial direction.

In the present embodiment, when the material of the brake disc 5B is a metal different from the material of the pulsar ring 77 (for example, copper) such as lightweight duralumin, the surface of the pulsar ring 77 is contacted with the brake disc 5B. It is desirable to apply a paint or coating to prevent erosion.

In this embodiment, known bell housings and rotors may be used as the first member 71 and the second member 72, respectively.

As described above, in the present embodiment, by using the pulsar ring 77, the detected portion 61 can be easily formed on the surface of the hat portion 52 of the brake disc 5B facing inward in the vehicle width direction.

Further, since the outer peripheral edge portion of the pulsar ring 77 is configured to be fastened together with the first member 71 and the second member 72, it is not necessary to arrange a bolt for attaching the pulsar ring in the hat portion 52. Therefore, according to the present embodiment, it is possible to prevent the outer diameter of the hat portion 52 from being enlarged as compared with the configuration in which the bolt for attaching the pulsar ring is passed through the bottom wall portion 53 of the hat portion 52. Therefore, it is possible to prevent the outer diameter of the entire brake disc 5B from expanding. As a result, it is possible to prevent deterioration of the ride quality and running performance of the vehicle due to the increase in unsprung weight.

Further, in the present embodiment, when a detection failure occurs due to thermal strain of the detected portion 61, only the pulsar ring 77 needs to be replaced, so that the repair cost can be suppressed as compared with the second embodiment.

In each embodiment, the passive type wheel speed rotating device has been described, but the active type may be adopted. In that case, for example, a known magnetic encoder can be adopted as the detected unit. The magnetic encoder is an annular magnet in which north poles and south poles are repeatedly arranged in the circumferential direction. In this case, the rotation sensor 62 reads the strength of magnetism accompanying the rotation of the magnetic encoder.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 in-wheel motor drive, 5,5A, 5B brake disc, 6,6A, 6B wheel speed detector, 10 casing, 11 wheel hub bearing, 12 inner ring, 12f flange, 13 outer ring, 14 rolling element, 15 output Shafts, 18 knuckles, 20 motor housings, 21 motors, 22 motor shafts, 74 protrusions, 23 rotors, 24 stators, 27, 28, 32m, 32n, 34m, 34n, 36m, 36n rolling bearings, 30 reducer housings, 31 reduction gear, 32 input gear, 33, 35 intermediate gear, 34 intermediate shaft, 36 output gear, 51 rotor, 52 hat, 53 bottom wall, 54 outer circumference, 61 detected, 62 rotation sensor, 71st 1 member, 72 2nd member, 73 connecting part, 76 fastening bolt, 77 pulsar ring, 80 brake pad, 81 brake caliper, 82, 83, 84 bolt, W wheel wheel.

Claims (7)

It includes an electric motor for driving the wheels, a speed reducer that decelerates and outputs the rotation of the electric motor, a wheel hub bearing portion that transmits the output of the speed reducer to the wheels, and a casing that accommodates the speed reducer. It is a wheel speed detection device that detects the rotation of the wheel in which the in-wheel motor drive device is arranged inside.
The wheel hub bearing portion of the in-wheel motor drive device includes a wheel hub coaxially coupled to a brake rotor having a hat portion formed so as to be recessed outward in the vehicle width direction.
A rotation sensor that detects the rotation of the brake rotor by forming a detected portion that causes a magnetic flux change in the circumferential direction on the surface of the hat portion that faces inward in the vehicle width direction and reading the magnetic flux change of the detected portion. A wheel speed detection device characterized by the provision of. The hat portion has an inner surface to which the flange portion of the wheel hub is fixed in a contact state.
The wheel speed detecting device according to claim 1, wherein the detected portion is formed at a position radially outside the flange portion and overlapping the flange portion in the axial direction. The wheel speed detection device according to claim 2, wherein the detected portion is formed on the inner surface of the hat portion. The brake rotor is a separate body from the first member having the inner side surface of the hat portion and the first member, and is located inside the first member in the vehicle width direction of the first member. The wheel speed detection device according to claim 3, further comprising a second member connected to an outer peripheral portion. The brake rotor is a separate body from the first member having the inner side surface of the hat portion and the first member, and is located inside the first member in the vehicle width direction of the first member. Includes a second member connected to the radial outer end
The wheel speed detection device according to claim 2, wherein the detected portion is composed of an annular member that is fastened together between the first member and the second member. The wheel speed detection device according to any one of claims 1 to 5, wherein the rotation sensor is attached to the casing of the in-wheel motor drive device or a knuckle fixed to the casing. An in-wheel motor drive device equipped with the wheel speed detection device according to claim 1.

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