JP5615033B2 - In-wheel motor drive device - Google Patents

Description

  The present invention relates to an in-wheel motor drive device, and more particularly to an in-wheel motor drive device provided with a sensor.

  As a technique for controlling the running stability of an electric vehicle, in an in-wheel motor drive device, for example, a technique in which sensors for measuring forces in three axial directions perpendicular to a ground point of a drive wheel and a road surface are attached is disclosed in, for example, No. 2008-74135 (Patent Document 1). According to Patent Document 1, the sensor is attached to a wheel bearing.

  Japanese Patent Laid-Open No. 2009-128264 (Patent Document 2) discloses a technique in which a sensor is attached to a wheel bearing, as in Patent Document 1.

JP 2008-74135 A JP 2009-128264 A

  The sensors disclosed in Patent Document 1 and Patent Document 2 are connected to a unit that processes a signal output from the sensor via a signal cable. Here, the signal cable is disposed on the outer surface of the in-wheel motor drive device, and vibrates together with the vibration of the wheel. In that case, the signal cable swings unstably on the outer surface of the apparatus. Furthermore, the signal cable bends when it swings, and noise may occur in the signal at the bent portion, for example.

  The objective of this invention is providing the in-wheel motor drive device which can position a signal cable stably.

An in-wheel motor drive device according to the present invention includes a wheel bearing having an outer ring that is a stationary side raceway and an inner ring that is a rotation side raceway, and rotatably supporting a hub of the drive wheel, and rotation of the drive wheel It is an in-wheel motor drive device provided with the electric motor used as a drive source, and the reduction gear interposed between an electric motor and a wheel bearing. And it is a substantially cylindrical shape, is attached to the casing that covers the electric motor and the speed reducer, is attached to the outer ring and detects the input and output states with respect to the drive wheel, and is attached to the casing. Based on the output signal that is output, provided in the middle of the signal processing unit that performs the predetermined processing, the signal cable that connects the sensor and the signal processing unit, and the signal cable from the sensor to the signal processing unit, engages at least a portion of the signal cable to the casing, provided with a locking portion for fixing the spacing between the casing and the signal cable, the signal cable is Ru is elastically fixed to the outer ring of the wheel bearing.

  In this way, the in-wheel motor drive device locks at least a part of the signal cable to the casing by the locking portion, and fixes the interval between the casing and the signal cable. Can be restricted. As a result, the signal cable can be stably positioned.

  Preferably, the locking portion includes a fixing member that is fixed to the outer diameter surface of the casing and has a cylindrical passage that can receive the outer peripheral surface of the signal cable. By doing so, the interval between the casing and the signal cable can be fixed using the fixing member. In this case, since the locking portion is attached to the outer diameter surface of the casing, it can be easily attached.

  More preferably, the fixing member includes a support portion attached to the outer diameter surface of the casing, and a lid portion that is detachable from the support portion and is disposed to face the support portion in a radial direction, By sandwiching a part of the cable between the support part and the cover part, at least a part of the signal cable is locked to the casing, and the interval between the casing and the signal cable is fixed. By carrying out like this, the space | interval of a casing and a signal cable can be firmly fixed using a support part and a cover part.

  More preferably, the cylindrical passage is constituted by a dent in the radial direction from the facing surface on at least one of the facing surfaces of the support portion and the lid portion facing each other. By doing so, the interval between the casing and the signal cable can be firmly fixed by fitting the signal cable into the recess.

  More preferably, the locking portion is a recess provided in the casing and recessed from the outer diameter surface of the casing. By carrying out like this, a latching | locking part can be provided in a casing and the number of members which comprise an in-wheel motor drive device can be suppressed.

  In another embodiment, the locking portion is a pressing member that presses the signal cable against the outer diameter surface of the casing.

  More preferably, the corner portion of the region where the signal cable contacts is chamfered or rounded. By doing so, the stress applied to the signal cable can be relaxed.

  More preferably, the signal cable includes a connection terminal capable of dividing the midway path of the signal cable, and the locking portion locks the connection terminal to the casing and fixes the interval between the casing and the signal cable.

  In this way, the in-wheel motor drive device locks at least a part of the signal cable to the casing by the locking portion, and fixes the interval between the casing and the signal cable. Can be restricted. As a result, the signal cable can be stably positioned, noise can be prevented, and extremely high reliability can be obtained.

It is a schematic diagram of the in-wheel motor drive concerning one embodiment of this invention. It is sectional drawing of the wheel bearing and speed reducer of an in-wheel motor drive device. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. It is sectional drawing which expands and shows the principal part of FIG. It is sectional drawing of a brake. It is the front view which looked at the outward member in the bearing for wheels from the outboard side. It is an enlarged plan view of a sensor unit. It is VIII-VIII arrow sectional drawing in FIG. It is sectional drawing which shows the other example of installation of a sensor unit. It is an enlarged plan view of another example of the sensor unit. It is an expanded sectional view of other examples of a sensor unit. It is the enlarged plan view which looked at the latching | locking part from the outer diameter side. It is XIII-XIII arrow sectional drawing of FIG. It is the front view seen from XIV of FIG. It is a block diagram of the signal processing unit which processes the sensor output signal of a sensor unit. It is a wave form diagram of a sensor output signal of a sensor unit. It is a schematic explanatory drawing of the signal processing in a signal processing unit. It is a block diagram of a control system. It is the external appearance schematic of an in-wheel motor drive device.

  1 to 18 show an embodiment of the present invention. First, an outline of this embodiment will be described with reference to FIG. This in-wheel motor drive device includes a wheel bearing A that rotatably supports a hub of a drive wheel 70, an electric motor B as a rotational drive source, and a deceleration that decelerates the rotation of the electric motor B and transmits it to the hub. The machine C and the brake D that applies a braking force to the hub are arranged on the central axis O of the drive wheel 70. The phrase “arranged on the central axis O” as used herein does not necessarily mean that each component is located on the central axis O, but that each component is functionally acting on the central axis O. That is. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side.

  As shown in FIG. 2, the wheel bearing A includes an outer ring 1 in which double-row rolling surfaces 3 are formed on the inner periphery, and an inner surface in which rolling surfaces 4 that face the respective rolling surfaces 3 are formed on the outer periphery. It comprises a member 2 and double row rolling elements 5 interposed between the rolling surfaces 3 and 4 of the outer ring 1 and the inner member 2. The wheel bearing A is a double-row angular ball bearing type, and the rolling elements 5 are formed of balls and are held by a cage 6 for each row. The rolling surfaces 3 and 4 have a circular arc shape in cross section, and the rolling surfaces 3 and 4 are formed so that the contact angles are aligned with the back surface. The outboard side end and the inboard side end of the bearing space between the outer ring 1 and the inner member 2 are sealed by seal members 7 and 8, respectively.

  The outer ring 1 is a stationary raceway, and has a flange 1a attached to the casing 33 of the speed reducer C on the outer periphery, and the whole is an integral part. The flange 1a is provided with screw holes 14 at a plurality of locations in the circumferential direction. The outer ring 1 is attached to the casing 33 by screwing the mounting bolts 15 inserted into the bolt insertion holes 33 a of the casing 33 into the screw holes 14.

  The inner member 2 serves as a rotating raceway, and includes a hub wheel 9 having a hub flange 9a for mounting the drive wheel 70 and the brake wheel 46, and an inboard side end of the shaft portion 9b of the hub wheel 9. The inner ring 10 is fitted on the outer periphery. The hub wheel 9 and the inner ring 10 are formed with the rolling surfaces 4 of the respective rows. The hub wheel 9 corresponds to a “hub” in the claims. An inner ring fitting surface 12 having a small diameter with a step is provided on the outer periphery of the inboard side end of the hub wheel 9, and the inner ring 10 is fitted to the inner ring fitting surface 12. A through hole 11 is provided in the center of the hub wheel 10. The hub flange 9a is provided with press-fitting holes 17 for hub bolts 16 at a plurality of locations in the circumferential direction. In the vicinity of the base portion of the hub flange 9a of the hub wheel 9, a cylindrical pilot portion 13 for guiding the drive wheel 70 and the brake wheel 46 protrudes toward the outboard side. A cap 18 that closes the outboard side end of the through hole 11 is attached to the inner periphery of the pilot portion 13.

  As shown in FIG. 1, the electric motor B is a radial gap type in which a radial gap is provided between a stator 23 fixed to a cylindrical casing 22 and a rotor 25 attached to an output shaft 24. The output shaft 24 is supported on the casing 22 by two bearings 26. The electric motor B is controlled by a motor control unit 137 including a control circuit including an inverter and the like. The electric motor B is connected to a power cable (not shown) for supplying electric power for rotationally driving the electric motor, and the power cable passes through the outer diameter surface of the casing 22 of the electric motor B. Are wired.

  As shown in FIGS. 2 and 3, the speed reducer C is configured as a cycloid speed reducer. In other words, the speed reducer C has two curved plates 34a and 34b formed with wavy trochoidal curves having a gentle outer shape, mounted on the eccentric portions 32a and 32b of the input shaft 32 via bearings 35, respectively. A plurality of outer pins 36 interposed between the inboard side wall and the outboard side wall of the casing 33 guide the eccentric movement of the curved plates 34a and 34b on the outer peripheral side, and are spline fitted into the through hole 11 of the hub wheel 9. Then, a plurality of inner pins 38 attached to the output shaft 37 that rotates integrally are inserted and inserted into a plurality of through holes 39 provided inside the curved plates 34a and 34b. The input shaft 32 is spline-coupled with the output shaft 24 of the electric motor B so as to rotate integrally. The input shaft 32 is supported at both ends by two bearings 40 on the inner surface of the casing 33 and the output shaft 37. Further, the trochoid curve that is the outer shape of the curved plates 34a and 34b is preferably a cycloid curve, but may be another trochoid curve. The above-mentioned “cycloid speed reducer” includes the trochoidal speed reducer which is a speed reducer having an outer shape as described above.

  When the output shaft 24 of the electric motor B rotates, the curved plates 34a and 34b attached to the input shaft 32 that rotates integrally with the output shaft 24 perform an eccentric motion. The eccentric motion of each of the curved plates 34a and 34b is transmitted as rotational motion to the inner member 2 which is a wheel hub by the engagement of the inner pin 38 and the through hole 39. The rotation of the inner member 2 is decelerated with respect to the rotation of the output shaft 24. For example, a reduction ratio of 1/10 or more can be obtained with a single-stage cycloid reducer.

  The two curved plates 34a and 34b are mounted on the eccentric portions 32a and 32b of the input shaft 32 so as to cancel the eccentric motion with respect to each other, and are respectively attached to both sides of the eccentric portions 32a and 32b. A counterweight 41 that is eccentric in the direction opposite to the eccentric direction of each of the eccentric portions 32a and 32b is mounted so as to cancel the vibration caused by the eccentric movement of each of the curved plates 34a and 34b.

  As shown in FIG. 4, bearings 42 and 43 are mounted on the outer pins 36 and the inner pins 38, and the outer rings 42a and 43a of the bearings 42 and 43 are respectively connected to the outer circumferences of the curved plates 34a and 34b and the outer rings 42a and 34b. It comes into rolling contact with the inner periphery of the through hole 39. Therefore, the contact resistance between the outer pin 36 and the outer periphery of each curved plate 34a, 34b and the contact resistance between the inner pin 38 and the inner periphery of each through hole 39 are reduced, and the eccentric motion of each curved plate 34a, 34b is smooth. Can be transmitted to the inner member 2 as a rotational motion.

  As shown in FIG. 5, the brake D operates the brake pad 47 with the brake wheel 46 attached to the hub flange 9 a together with the drive wheel 70, the brake pad 47 capable of frictional contact with the brake wheel 46, and the brake pad 47. The drive unit 49 is an electric brake using a brake electric motor 50 as a drive source of the drive unit 49. The brake wheel 46 is composed of a brake disk. A pair of brake pads 47 are provided so as to sandwich the brake wheel 46 therebetween. One brake pad 47 is fixed to the brake frame 51, and the other brake pad 47 is attached to an advancing / retracting member 52 that is linearly movable on the brake frame 51. The advancing and retracting direction of the advancing / retracting member 52 is a direction facing the brake wheel 46. The advance / retreat member 52 is prevented from rotating with respect to the brake frame 51.

  The drive unit 49 includes the brake electric motor 50, and a ball screw 53 that converts the rotation output of the electric motor 50 into a reciprocating linear motion and transmits it to the brake pad 47 as a braking force. The output of the electric motor 50 is This is transmitted to the ball screw 53 via the deceleration transmission mechanism 58. In the ball screw 53, a screw shaft 54 is supported by the brake frame 51 via a bearing 57 so as to be rotatable only, and a nut 55 is fixed to the advance / retreat member 52. The advancing / retracting member 52 and the nut 55 may be integrated with each other.

  The ball screw 53 includes a screw shaft 54 and a nut 55, and a plurality of balls 56 interposed between screw grooves formed to face the outer peripheral surface of the screw shaft 54 and the inner peripheral surface of the nut 55. The nut 55 has a circulating means (not shown) for circulating a ball 56 interposed between the screw shaft 54 and the nut 55 through an endless path. The circulation means may be an external circulation type using a return tube or a guide plate or an internal circulation type using an end cap or a piece. Since the ball screw 53 reciprocates over a short distance, the ball screw 53 does not have the circulating means, for example, a plurality of balls 56 between the screw shaft 54 and the nut 55 are retained by a retainer (not shown). A retained retainer type may be used.

  The deceleration transmission mechanism 58 is a mechanism that decelerates and transmits the rotation of the brake electric motor 50 to the screw shaft 54 of the ball screw 53, and includes a gear train. In this example, the speed reduction transmission mechanism 58 includes a gear 59 provided on the output shaft of the electric motor 50 and a gear 60 provided on the screw shaft 54 and meshing with the gear 59. In addition to this, the deceleration transmission mechanism 58 may be composed of, for example, a worm and a worm wheel (not shown).

  The brake D includes an operation unit 62 that controls the electric motor 50 in accordance with an operation of an operation member 61 such as a brake pedal. The operation unit 62 is provided with antilock control means 65. The operation unit 62 includes the operation member 61, a sensor 64 capable of detecting the operation amount and operation direction of the operation member 61, and a control device 63 that controls the electric motor 50 in response to a detection signal of the sensor 64. Thus, the anti-lock control means 65 is provided in the control device 63. The control device 63 has means for generating a motor control signal and a motor drive circuit (none of which is shown) that can control the motor current by the motor control signal.

  The anti-lock control means 65 is a means for preventing the rotation lock of the drive wheel 70 by adjusting the braking force by the electric motor 50 according to the rotation of the drive wheel 70 during braking by operating the operation member 61. The anti-lock control means 65 detects the rotational speed of the driving wheel 70 during the braking, and when the rotational locking of the driving wheel 70 or an indication thereof is detected from the detected speed, reduces the driving current of the electric motor 50, or A process of adjusting the braking force, that is, the tightening force of the brake pad 47, is performed by temporarily generating a reverse rotation output. For detection of the rotational speed of the drive wheel 70, the output of the rotational speed sensor 87 provided in the electric motor B is used.

  As shown in FIG. 1, a drive wheel 70 is attached to the hub flange 9 a of the wheel bearing A together with the brake wheel 46. The drive wheel 70 is provided with a tire 72 around the wheel 71. With the brake wheel 46 sandwiched between the hub flange 9a and the wheel 71, the hub bolt 16 press-fitted into the press-fitting hole 17 of the hub flange 9a is screwed into the wheel 71, whereby the drive wheel 70 and the brake wheel 46 are connected to the hub. It is fixed to the flange 9a.

  Four sensor units 120 are provided on the outer diameter surface of the outer ring 1 that is a stationary side race. FIG. 6 shows a front view of the outer ring 1 viewed from the outboard side. Here, these sensor units 120 are provided on the upper surface portion, the lower surface portion, the right surface portion, and the left surface portion of the outer diameter surface of the outer ring 1 that is in the vertical position and the horizontal position with respect to the tire ground contact surface.

  These sensor units 120 include a strain generating member 121 and a strain that is attached to the strain generating member 121 and detects the strain of the strain generating member 121, as shown in an enlarged plan view and an enlarged sectional view in FIGS. It consists of a sensor 122. The strain generating member 121 is made of an elastically deformable metal plate having a thickness of 3 mm or less, such as a steel material, and has a planar shape of a strip having a uniform width over the entire length, and has notches 121b on both sides of the center. Further, the strain generating member 121 has two contact fixing portions 121 a that are fixed to the outer diameter surface of the outer ring 1 through spacers 123 at both ends. The strain sensor 122 is affixed to the strain generating member 121 at a location where the strain increases with respect to the load in each direction. Here, as the location, the central portion sandwiched between the notch portions 121b on both sides on the outer surface side of the strain generating member 121 is selected, and the strain sensor 122 measures the circumferential strain around the notch portion 121b. To detect. It should be noted that the strain generating member 121 does not plastically deform even in a state where the maximum force assumed as an external force acting on the outer ring 1 that is the stationary side raceway or an acting force acting between the tire and the road surface is applied. It is desirable to be. This is because when the plastic deformation occurs, the deformation of the outer ring 1 is not transmitted to the sensor unit 120 and affects the measurement of strain. The “maximum force expected” is the range in which the normal function as a wheel bearing excluding the sensor system is restored even if an abnormally large force is applied to the wheel bearing A. Is the greatest power of.

  In the sensor unit 120, the two contact fixing portions 121a of the strain generating member 121 are positioned at the same size in the axial direction of the outer ring 1, and the two contact fixing portions 121a are located at positions separated from each other in the circumferential direction. These contact fixing portions 121a are fixed to the outer diameter surface of the outer ring 1 by bolts 124 through spacers 123, respectively. Each of the bolts 124 is inserted into a bolt insertion hole 126 of the spacer 123 through a bolt insertion hole 125 provided in the contact fixing portion 121a in the radial direction and screwed into a screw hole 127 provided in the outer peripheral portion of the outer ring 1. Combine. In this way, by fixing the contact fixing portion 121a to the outer diameter surface of the outer ring 1 via the spacer 123, the central portion having the notch portion 121b in the thin plate-shaped strain generating member 121 is the outer diameter surface of the outer ring 1. It becomes a state away from, and distortion deformation around the notch 121b becomes easy. As the axial position where the contact fixing portion 121a is arranged, an axial position that is the periphery of the rolling surface 3 of the outboard side row of the outer ring 1 is selected here. Here, the periphery of the rolling surface 3 of the outboard side row is a range from the intermediate position of the rolling surface 3 of the inboard side row and the outboard side row to the formation portion of the rolling surface 3 of the outboard side row. It is. A flat portion 1 b is formed at a location where the spacer 123 is fixed in contact with the outer diameter surface of the outer ring 1.

  In addition, as shown in a cross-sectional view in FIG. 9, grooves 1 c are provided at two intermediate portions where the two contact fixing portions 121 a of the strain generating member 121 are fixed on the outer diameter surface of the external member 1. The spacer 123 may be omitted, and the intermediate part of the two contact fixing parts 121a where the notch part 121b of the strain generating member 121 is located may be separated from the outer diameter surface of the outer ring 1.

  Further, as shown in FIG. 10, the strain generating member 121 may be a belt having a monotonous plane outline and not forming the notch 121 b as in the example of FIG. 7.

  Various strain sensors 122 can be used. For example, the strain sensor 122 can be composed of a metal foil strain gauge. In that case, the distortion generating member 121 is usually fixed by adhesion.

  Further, the strain sensor 122 can be formed on the strain generating member 121 with a thick film resistor. The structure of the sensor unit 120 in that case is shown in FIG. In this sensor unit 120, an insulating layer 150 is formed on the sensor mounting surface 121 A of the strain generating member 121, and pairs of electrodes 151 and 151 are formed on both sides of the surface of the insulating layer 150. A strain measuring resistor 152 serving as a strain sensor is formed on the insulating layer 150, and a protective film 153 is further formed on the electrodes 151 and 151 and the strain measuring resistor 152. .

  The sensor unit 120 attached to the outer diameter surface of the outer ring 1 is covered with a protective cover 90 as shown in FIG. In FIG. 6, the protective cover 90 is omitted. The protective cover 90 has a cylindrical shape whose inner diameter increases toward the inboard side. Specifically, the protective cover 90 has a cylindrical shape having a large-diameter portion on the inboard side and a small-diameter portion in which the half portion on the outboard side is reduced toward the inner diameter side. The inboard side end of the protective cover 90 is attached to the outer diameter surface of the flange 1 a of the outer ring 1 via the O-ring 91, and the outboard side end of the protective cover 90 is fitted to the outer diameter surface of the outer ring 1. As a material of the protective cover 90, a metal material such as stainless steel or a resin material such as PA66 + GF is used. A groove 1d for fitting an O-ring extending in the circumferential direction is provided on the outer diameter surface of the flange 1a of the outer ring 1, and the O-ring 91 is positioned in the axial direction by fitting the O-ring 91 in the groove 1d. At the same time, the gap between the inboard side end of the protective cover 90 and the outer diameter surface of the flange 1a of the outer ring 1 is securely sealed. In addition, a resin mold or the like is applied around the installation portion of the sensor unit 120 to perform waterproofing.

  Thus, since the sensor unit 120 is fixed to the outer diameter surface of the outer ring 1 in the protective cover 90, it is possible to prevent the fixing portions from being corroded by the external environment and becoming unstable. The sensor unit 120 can be operated normally while being used in a severe environment around the foot.

  Each sensor unit 120 is connected to the signal processing unit 130 via a signal cable 129. The signal processing unit 130 is a signal processing device having load estimation means 133 that estimates the load applied to the drive wheel 70 from the sensor output signal of each sensor unit 120. Here, the signal processing unit 130 is connected to the outboard side end of the casing 33 of the speed reducer C. It is installed on the outer diameter surface. The signal processing unit 130 may be installed on the outer diameter surface of the outer ring 1 together with the sensor unit 120, or may be installed on the outer diameter surface of the casing 22 of the electric motor B.

  The flange 1a of the outer ring 1 is provided with a cable insertion hole 92 through which the signal cable 129 of each sensor unit 120 is pulled out in the axial direction. After the signal cable 129 is pulled out, the cable insertion hole 92 is molded resin or the like. The elastic filler 93 is filled.

  The signal cable 129 exiting the cable insertion hole 92 is drawn out to the signal processing unit 130 via a cable guide notch 33b formed at the outboard side end of the casing 33 of the speed reducer C. The periphery of the signal cable 129 is waterproofed by a waterproof seal member 94. The notch 33b may be a through hole that opens to the outer diameter surface. Thereby, it can prevent that muddy water, salt water, etc. penetrate | invade into the protective cover 90 through the cable penetration hole 92 from the outside.

  In addition, the wiring from the sensor unit 120 to the signal processing unit 130 is configured to pass through the inside of the casing 33 of the reduction gear C so that the signal cable 129 is connected to the signal processing unit 130 without going outside. May be. In this case, since the signal cable 129 is not exposed to the outside and the intrusion route such as muddy water can be minimized, the waterproof performance can be improved and the reliability can be improved.

  Here, the wiring state of the signal cable 129 will be described in detail.

  The signal cable 129 exiting from the cable insertion hole 92 is fixed to the casing 33 of the speed reducer C by a locking portion 95 attached to the casing 33 of the speed reducer C. The locking portion 95 is attached to the inboard side of the sensor unit 120 and to the outboard side of the signal processing unit 130. FIG. 12 is an enlarged plan view of the locking portion 95 viewed from the outer diameter side. 13 is a cross-sectional view taken along arrow XIII-XIII in FIG. FIG. 14 is a front view seen from XIV (inboard side) of FIG. The locking part 95 locks at least a part of the signal cable 129, and fixes the interval between the casing 33 of the reduction gear C and the signal cable 129. The signal cable 129 is provided along the route from the sensor unit 120 to the signal processing unit 130. The locking portion 95 is a fixing member that is fixed to the outer diameter surface of the casing 33 of the speed reducer C and has a cylindrical passage 95 a that can receive the outer peripheral surface of the signal cable 129. Specifically, the locking portion 95 is detachable from the support portion 97 attached to the outer diameter surface of the casing 33 of the reduction gear C and the support portion 97, and faces the radial direction of the support portion 97. And a lid portion 96 disposed. The support portion 97 is substantially L-shaped, and includes a contact portion 97e that contacts the outer diameter surface of the casing 33 of the speed reducer C, and an extension portion 97f that extends from the inboard side end portion of the contact portion 97e to the outer diameter side. Including. Then, the signal cable 129 is received by the recess 96c provided on the facing surface facing the lid portion 96 of the extending portion 97f and the recess 97c provided on the facing surface facing the extending portion 97f of the lid portion 96. A cylindrical passage 95a is formed. The cylindrical passage 95 is, for example, circular when viewed from the inboard side and has a size along the diameter of the signal cable 129. And it is biased to one side in the circumferential direction. Of the extending portion 97f and the lid portion 96, the corner portions 97b and 96b on the inboard side and the outboard side that are in contact with the signal cable 129 are both chamfered. For the chamfering, for example, R chamfering or C chamfering can be applied. The locking portion 95 is to lock the signal cable 129 to the casing 33 of the speed reducer C by sandwiching a part of the signal cable 129 between the support portion 97 and the lid portion 96. In addition, the area | region 33a to which the latching | locking part 95 is fixed among the casings 33 of the reduction gear C has a flat shape.

  Further, the support portion 97 is firmly fixed to the casing 33 of the speed reducer C by screwing the casing 33 of the speed reducer C and the contact portion 97e of the support portion 97 with a bolt 99. Further, the lid portion 96 is firmly fixed to the support portion 97 by screwing the extending portion 97f of the support portion 97 and the lid portion 96 with a bolt 98. The bolts 99 may be provided on both sides of the tubular passage 95a in a direction perpendicular to the direction in which the signal cable 129 extends, or may be provided on only one side as shown in FIG. The same applies to the bolt 98.

  FIG. 15 is a block diagram illustrating a schematic configuration of the signal processing unit 130. The signal processing unit 130 includes preprocessing means 131, average / amplitude extraction means 132, load estimation means 133, parameter storage means 134, and communication means 135 having an I / F function. The preprocessing means 131 has a function of amplifying sensor output signals from each sensor unit 120, a filtering function for removing noise components from these sensor output signals, and an AD conversion function for AD converting the amplified and filtered sensor output signals. have. Thereby, since the weak sensor output signal from the sensor unit 120 is converted into a digital signal by the signal processing unit 130 installed nearby, it is less susceptible to noise, and the detection accuracy can be improved. The average / amplitude extraction unit 132 has a function of extracting an average value and an amplitude value, which will be described later, from the sensor output signal that has passed through the preprocessing unit 131, and a function of correcting the extracted average value and the like. The load estimation unit 133 has a function of estimating a load applied to the drive wheel 70 using the average value and the amplitude value extracted by the average / amplitude extraction unit 132. As described above, since the calculation of the sensor output signal of the sensor unit 120 is all performed by the signal processing unit 130, the usability is improved and the number of external wirings is minimized, and the reliability is improved.

  Since the sensor unit 120 is provided at an axial position around the rolling surface 3 on the outboard side row of the outer ring 1, the output signal of the strain sensor 122 passes through the vicinity of the installation portion of the sensor unit 120. Influenced by 5. That is, when the rolling element 5 passes the position closest to the strain sensor 122 in the sensor unit 120, the amplitude of the sensor output signal becomes the maximum value, and decreases as the rolling element 5 moves away from the position. Thereby, the sensor output signal becomes a waveform close to a sine wave as shown in FIG. 16 in which the amplitude changes with the arrangement pitch of the rolling elements 5 as a period when the bearing rotates. Therefore, the average / amplitude extraction means 132 calculates and extracts the amplitude value (AC component) and the average value (DC component) of the sensor output signal as data for obtaining the load.

  The average value calculated by the average / amplitude extraction means 132 includes the temperature characteristics of the strain sensor 122 itself, the temperature distortion of the outer ring 1, and a drift amount due to other causes. Therefore, the average / amplitude extraction unit 132 corrects the drift of the sensor output signal. Parameters for the correction are stored in the parameter storage unit 134, read out from the parameter storage unit 134, and used for correcting the drift. The parameter storage unit 134 is composed of, for example, a nonvolatile memory. In addition, in order to correct drift due to temperature, for example, a temperature sensor 128 is provided in the strain generating member 121 of at least one sensor unit 120 as indicated by an imaginary line in FIG. 7, and an output signal of the temperature sensor 128 is supplied to the sensor unit 120. The sensor output signal may be input to the average / amplitude extraction means 132 via the preprocessing means 131 and used for drift correction. In this case, information necessary for the temperature sensor 128 may also be stored in the parameter storage unit 134. The arithmetic expressions and correction parameters used in the average / amplitude extraction means 132 are determined in advance by tests and simulations and set.

  In the load estimation means 133, the average value and the amplitude value calculated and extracted by the average / amplitude extraction means 132 are used as variables, and a load (vertical) applied to the drive wheels 70 from a linear expression obtained by multiplying these variables by a predetermined correction coefficient. The directional load Fz, the load Fx serving as a driving force or a braking force, and the axial load Fy) are estimated. The correction coefficient in the linear expression is also stored in the parameter storage unit 134 and is read out from the parameter storage unit 134 and used. In this case, the correction coefficient is also obtained and set in advance by a test or simulation. The load data obtained by the load estimating means 133 is electrically controlled by communication (for example, via a CAN bus) with a host electric control unit (ECU) 85 (FIG. 18) installed on the vehicle body side via the communication means 135. It is output to the unit 85. The load data may be output as an analog voltage as necessary. Various parameters stored in the parameter storage unit 134 may be externally written through the communication unit 135. FIG. 17 shows a schematic flow of processing until each load Fx, Fy, Fz is estimated by the load estimation means 133 from the sensor output signal of the sensor unit 120.

  When a load acts between the drive wheel 70 and the road surface, the load is also applied to the outer ring 1 that is the stationary side race of the wheel bearing A, and deformation occurs. Here, since the two contact fixing portions 121 a of the strain generating member 121 made of a thin plate material in the sensor unit 120 are fixed in contact with the outer diameter surface of the outer ring 1, the distortion of the outer ring 1 expands to the strain generating member 121. The distortion is easily transmitted and the distortion sensor 122 detects the distortion with high sensitivity.

  Further, in this embodiment, the four sensor units 120 are provided, and each sensor unit 120 is provided with an upper surface portion, a lower surface portion, a right surface portion of the outer diameter surface of the outer ring 1 that is in a vertical position and a horizontal position with respect to the tire ground contact surface In addition, since the left surface portion is equally distributed with a phase difference of 90 degrees in the circumferential direction, the vertical load Fz acting on the wheel bearing A, the load Fx serving as a driving force and a braking force, and the axial load Fy are accurately estimated. can do.

  As shown in FIG. 18, the electric control unit 85 to which the load data is input is provided with an abnormality determination means 84 that determines from the load data that the road surface state and the grounding state of the driving wheel 70 and the road surface are abnormal. It has been. Further, the electric motor B, the electric motor 50 of the brake C, and the damping means 74 of the suspension D are connected to the output side of the electric control unit 85, and the electric control unit 85 is sent from the signal processing unit 130. Based on the load data, information on the road surface state and the grounding state of the driving wheel 70 and the road surface is output to the electric motor B, the electric motor 50 of the brake C, and the damping means 74 of the suspension D.

  As described above, the electric control unit 85 outputs information on the road surface state and the ground contact state between the driving wheel 70 and the road surface based on the load data sent from the signal processing unit 130. The grounding state can be estimated more accurately. The various information obtained in this way can be used for controlling the electric motor B and controlling the attitude of the vehicle, thereby improving safety and economy. For example, the information is output to the electric motor B so that the rotational speed of the left and right drive wheels 70 is controlled so that the vehicle turns smoothly. The information is output to the electric motor 50 of the brake D to control the braking so that the driving wheel 70 is not locked during braking. In order to prevent the vehicle body from being greatly tilted to the left and right during turning, and the vehicle body from being largely tilted back and forth during acceleration and braking, the information is output to the damping means 74 of the suspension 73 to perform suspension control. In addition, the abnormality determination unit 84 outputs an abnormality signal when it is determined that the force in the three axial directions has exceeded an allowable value. This abnormal signal can also be used for vehicle control of an automobile. Furthermore, if the acting force between the driving wheel 70 and the road surface is output in real time, more fine attitude control becomes possible.

  As described above, in this in-wheel motor drive device, the sensor unit 120 including the strain generating member 121 and one strain sensor 122 attached to the strain generating member 121 is used as an outer ring that is a stationary side race of the wheel bearing A. Since the strain generating member 121 is made of a thin plate material having two contact fixing portions 121a fixed in contact with the outer diameter surface of the outer ring 1, the grounding point between the driving wheel 70 and the road surface is provided. The sensor unit 120 can detect the distortion of the outer ring 1 of the wheel bearing A that is distorted by the force acting on the sensor. Accordingly, the loads Fx, Fy, and Fz acting on the driving wheel 70 and the ground contact point on the road surface are accurately calculated by calculating and estimating the load using a plurality of sensor output signals obtained by the sensor unit 120. It can be estimated and is effective in controlling the electric motor B and the vehicle with high accuracy.

  Further, in this way, in this in-wheel motor drive device, at least a part of the signal cable 129 is locked to the casing 33 of the reduction gear C by the locking portion 95, and the casing 33 of the reduction gear C and the signal In order to fix the space | interval with the cable 129, the movement of the signal cable 129, such as shaking, can be controlled. As a result, the signal cable 129 can be positioned stably.

  Moreover, since the latching | locking part 95 is attached to the outer diameter surface of the casing 33 of the reduction gear C, attachment can be performed easily. Further, stress applied to the signal cable can be relaxed by chamfering the corner portions 97b and 96b.

  In this embodiment, the signal processing unit 130 has a signal amplification function for amplifying the sensor output signal, a filtering function for removing a noise component from the sensor output signal, and an AD conversion function for AD converting the sensor output signal. Therefore, the sensor output signal of the sensor unit 120 is converted into a digital signal and used for load estimation, and the load data is also calculated and output as digital data. For this reason, the number of necessary electric wires is minimized, and the cost of the signal cable 129 to be used can be reduced. At the same time, the risk of breakage is reduced and reliability is improved.

  The signal processing unit 130 is further used for correction, a correction function for correcting the sensor output signal, an average value extraction function for obtaining the average value of the sensor output signal, an amplitude value extraction function for obtaining the amplitude value of the sensor output signal, and the correction. A calculation function including a correction function, a calculation parameter used for average value extraction and amplitude value extraction, and a storage function for storing a calculation parameter of an arithmetic expression used in the load estimation unit 133 using the average value and the amplitude value as variables. In particular, the influence of temperature can be reduced by the amplitude value, and an increase in load calculation error due to heat generated by the electric motor or the reduction gear can be suppressed, and the accuracy of load estimation can be increased accordingly. Further, since the signal processing unit 130 has such an arithmetic processing function, it is possible to easily adjust different correction parameters and calculation parameters for each apparatus.

  In this embodiment, the third generation type wheel bearing A in which the inner member forms part of the hub is used. However, the first or second generation type wheel in which the inner member and the wheel hub are independent from each other. It may be used as a bearing. Furthermore, it is good also as a wheel bearing which is a tapered roller type of each generation form.

  In this in-wheel motor drive device, since the brake D is an electric brake that moves the brake pad 47 by the electric motor 50, it is possible to avoid environmental pollution due to oil leakage that occurs in the hydraulic brake. Moreover, since it is an electric brake, the moving amount of the brake pad 47 can be quickly adjusted, and the responsiveness of the rotational speed control of the left and right drive wheels 70 during turning can be improved.

  Moreover, since this in-wheel motor drive device operates the damping means 74 of the suspension 73 electrically, the responsiveness of the suspension control can be improved and the vehicle posture can be stabilized.

  In the above description, the driving of the electric motor B, the operation of the brake D, and the operation of the suspension 73 are controlled from the output of the signal processing unit 130 that estimates the force in the three axial directions acting on the driving wheel 70 and the road surface. However, if each of the above controls including the signal from the steering device is performed, it is more desirable in performing the control in accordance with the actual traveling.

  In the above embodiment, the locking portion 95 includes the support portion 97 and the lid portion 96, and a part of the signal cable 129 is sandwiched between the support portion 97 and the lid portion 96. Although the example which fixes the space | interval of the casing 33 of the reduction gear C and the signal cable 129 was demonstrated by this, not only this but the latching | locking part 95 applies an adhesive agent to the wall surface of the cylindrical channel | path 95a. Thus, the signal cable may be firmly fixed by bonding the support portion 97 and the lid portion 96 to each other.

  Further, the locking portion 95 is not limited to the configuration in which the support portion 97 and the lid portion 96 are fixed by the bolt 98, and may be fitted to each other.

  Further, the locking portion 95 is not limited to the configuration in which the corner portions 97b and 96b are both chamfered, and an elastic member or the like may be provided in the corner portions 97b and 96b.

  In the above embodiment, the example in which the locking portion 95 includes the support portion 97 and the lid portion 96 has been described. However, the present invention is not limited to this, and for example, the rectangular fixing member has a through hole. The signal cable 129 may be inserted into the through hole, and at least a part of the signal cable 129 may be locked to the casing 33 of the speed reducer C. Further, in such a through hole, a configuration is provided in which a notch groove that opens a part of the wall surface constituting the through hole to the outside is provided, and by pushing the signal cable 129 from the notch groove to the through hole, The signal cable 129 may be inserted through the through hole.

  Moreover, you may provide the latching | locking part 95 in the casing 33 of the reduction gear C. FIG. For example, the outer diameter surface of the casing 33 of the speed reducer C may be a recess that is recessed from the outer diameter surface toward the inner diameter side, and the recess may have a shape such that the opening width becomes narrower toward the opening. Thus, when it provides in the casing 33 of the reduction gear C, the number of members of an in-wheel motor drive device can be suppressed.

  The engaging portion 95 may be a pressing member that presses the signal cable 129 against the outer diameter surface of the casing 33 of the reduction gear C, or the outer diameter surface of the casing 33 of the reduction gear C. The signal cable 129 may be locked by adhering to it through an adhesive.

  In the above embodiment, the sensor unit 120 includes the strain sensor 122, and the locking portion 95 connects the signal cable 129 from the sensor unit 120 including the strain sensor 122 to the signal processing unit 130. Although an example of locking has been described, the present invention is not limited thereto, and may be applied to a signal cable wired from a rotation speed sensor 87 that detects the rotation speed of the drive wheel 70, for example. The locking part 95 can be applied when locking a signal cable wired from any sensor.

  Furthermore, in the above-described embodiment, the example in which the locking portion 95 is attached to the casing 33 of the speed reducer C has been described. However, the present invention is not limited thereto, and as illustrated in FIG. It may be attached. FIG. 19 is a schematic external view of an in-wheel motor drive device. As shown in FIG. 19, a plurality of band-shaped band locking portions 100 are attached to the outer diameter surface of the casing 33 of the reduction gear C, and the locking portion 95 is fixed to the outer diameter surface of the casing 33 of the electric motor C. Is attached. The signal cable 129 that has exited the cable insertion hole 92 is fixed at a distance between the casing 33 of the speed reducer C and the signal cable 129 by the band locking portion 100, and the casing 22 of the electric motor B by the locking portion 95. The interval between and is fixed. As shown in FIG. 19, a portion corresponding to the casing 22 of the electric motor B in the signal cable 129 is provided with a connection terminal (connector) 101 by dividing the signal cable 129, and a locking portion 95. Thus, the connector 101 may be fixed to the casing 22 of the electric motor B. By doing so, the workability can be improved.

  In this case, it is desirable that the signal cable 129 is disposed at a different circumferential position from the power cable passing through the outer diameter surface of the casing 22 of the electric motor B. By doing so, it is possible to appropriately reduce the influence of noise caused by the power cable in the sensor output signal output from the sensor.

  Moreover, in said embodiment, although the casing 22 of the electric motor B and the casing 33 of the reduction gear C demonstrated the example comprised by another member, it is not restricted to this but is an integrated member. There may be.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The present invention is effectively used when a sensor is provided in an in-wheel motor drive device.

  DESCRIPTION OF SYMBOLS 1 Outer ring, 22 Electric motor casing, 33 Reduction gear casing, 70 Drive wheel, 95 Locking part, 120 Sensor unit, 121 Strain generating member, 121a Contact fixing part, 122, 122A, 122B Strain sensor, 130 Signal processing unit 133 Load estimation means, 137 Motor control unit.

Claims (8)

A wheel bearing having an outer ring that is a stationary side race ring and an inner ring that is a rotation side race ring, and rotatably supporting a hub of a drive wheel, an electric motor that serves as a rotational drive source of the drive wheel, and the electric An in-wheel motor drive device comprising a motor and a reduction gear interposed between the wheel bearings,
A substantially cylindrical shape and a casing covering the electric motor and the speed reducer;
A sensor attached to the outer ring for detecting input and output states with respect to the drive wheel;
A signal processing unit that is attached to the casing and performs predetermined processing based on an output signal output from the sensor;
A signal cable connecting the sensor and the signal processing unit;
Provided in the middle of the signal cable path from the sensor to the signal processing unit, locking at least a part of the signal cable to the casing, and fixing the interval between the casing and the signal cable and a locking unit that,
The signal cable Ru is elastically fixed to the outer ring of the wheel bearing, in-wheel motor drive device. 2. The in-wheel motor drive device according to claim 1, wherein the locking portion includes a fixing member that is fixed to an outer diameter surface of the casing and includes a cylindrical passage that can receive an outer peripheral surface of the signal cable. The fixing member includes a support portion attached to an outer diameter surface of the casing, and a lid portion that is detachable from the support portion and is disposed to face the support portion in a radial direction,
By holding a part of the signal cable between the support part and the lid part, at least a part of the signal cable is locked to the casing, and a distance between the casing and the signal cable is fixed. The in-wheel motor drive device according to claim 2. 4. The in-hole according to claim 3, wherein the cylindrical passage is configured by a dent in a radial direction from the facing surface on at least one of the facing surfaces of the support portion and the lid portion facing each other. Wheel motor drive device. The in-wheel motor drive device according to claim 1, wherein the locking portion is a recess provided in the casing and recessed from an outer diameter surface of the casing. The in-wheel motor drive device according to claim 1, wherein the locking portion is a pressing member that presses the signal cable against the outer diameter surface of the casing. The in-wheel motor drive device in any one of Claims 1-6 by which the corner | angular part of the area | region which the said signal cable contacts among the said latching | locking parts is chamfered or R-surface processed. The signal cable includes a connection terminal capable of dividing a midway path of the signal cable,
The in-wheel motor drive device according to any one of claims 1 to 7, wherein the locking portion locks the connection terminal to the casing and fixes a distance between the casing and the signal cable.

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