JP2011033350A - Tire acting force detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire acting force detecting device achieving both of improvement in measurement precision of tire acting force and suppression of excessive stress and deformation. <P>SOLUTION: The tire acting force detecting device 1-1 detects tire acting force in a vehicle including a hub 3 and a tire wheel 1. The tire acting force detecting device 1-1 includes a connection part 4a for connecting the hub to the wheel in an axle direction; and a detection means detecting the amount of deformation of the connection part to detect tire acting force based on the detected amount of deformation. Further, the tire acting force detecting device 1-1 includes a support member 4g disposed in parallel with the connection part between the hub and the wheel, fixed to one of the hub and wheel sides, and opposing the other 2 in an axle direction. When the connection part is deformed in an axle direction by a load for mutually bringing the hub and the wheel closer in an axle direction by the tire acting force, a gap between the support member and the other in an axle direction decreases. When the load is small, the support member is separated from the other and the connection part supports the load. When the load is large, the support member abuts on the other to support the load along with the connection part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tire acting force detection device, and more particularly to a tire acting force for detecting a tire acting force acting on a tire in a vehicle including a hub, a wheel connected to the hub, and a tire attached to the wheel. The present invention relates to a detection device.

  2. Description of the Related Art Conventionally, a tire acting force detection device that detects a tire acting force by a detector provided between a hub and a wheel has been proposed. For example, Patent Document 1 discloses a tire acting force detection device that includes a detector that detects a tire acting force and is provided between a wheel and a holding body (for example, a hub) in a state of transmitting force therebetween. Is disclosed.

JP 2003-14563 A

  Here, when the tire acting force detection device detects the tire acting force based on the deformation of the connecting portion that connects the wheel and the hub, in order to improve the measurement accuracy of the tire acting force, the connecting portion It is desirable that the amount of deformation is large. In terms of increasing the measurement accuracy of the tire acting force, for example, it is advantageous that the cross-sectional area in the direction orthogonal to the axle direction at the connecting portion is small. On the other hand, it is desirable to increase the cross-sectional area from the viewpoint of suppressing excessive stress from acting on the connecting portion or excessive deformation.

  In the tire action force detection device that detects the tire action force based on the deformation of the connection part that connects the wheel and the hub, the measurement accuracy of the tire action force is improved and excessive stress is applied to the connection part or excessive deformation. It is desired to be able to achieve both the suppression of the occurrence of water.

  The object of the present invention is to improve the measurement accuracy of the tire acting force and to apply excessive stress to the connecting portion when detecting the tire acting force based on the deformation of the connecting portion that connects the wheel and the hub in the axle direction. It is an object to provide a tire acting force detection device capable of achieving both suppression of excessive deformation and excessive deformation.

  The tire acting force detection device of the present invention acts on a tire in a vehicle including a hub rotatably supported around an axle, a wheel connected to the hub, and a tire attached to the wheel. A tire acting force detection device for detecting a tire acting force, comprising: a connecting portion for connecting the hub and the wheel in the axle direction; and a detecting means for detecting a deformation amount of the connecting portion. The tire acting force is detected based on the deformation amount detected by the vehicle, and is further arranged in parallel with the connecting portion between the hub and the wheel in the axle direction, and the hub side or the wheel side And a support member that is fixed to one of the two and faces the other in the axle direction, and a load that causes the hub and the wheel due to the tire acting force to approach each other in the axle direction. When the connecting portion is deformed in the axle direction, a gap in the axle direction between the support member and the other is reduced, and when the load is small, the support member is separated from the other, The connection portion supports the load, and when the load is large, the support member comes into contact with the other, and the load is supported by the connection portion and the support member.

  The tire acting force detection device of the present invention acts on a tire in a vehicle including a hub rotatably supported around an axle, a wheel connected to the hub, and a tire attached to the wheel. A tire acting force detection device for detecting a tire acting force, comprising: a connecting portion for connecting the hub and the wheel in the axle direction; and a detecting means for detecting a deformation amount of the connecting portion. The tire acting force is detected based on the deformation amount detected by the vehicle, and further includes a support member disposed in parallel with the connecting portion between the hub and the wheel in the axle direction, The connecting portion is deformed in the axle direction by a load that brings the hub and the wheel close to each other in the axle direction by force, so that the axle direction of the hub and the wheel is When the gap is reduced, the support member is supported at a position separated from the hub side and the wheel side in the axle direction when the load does not act, and when the load is small, The support member is separated from both the hub side and the wheel side, and the connection portion supports the load. When the load is large, the hub side and the wheel side and the support member are It abuts and the load is supported by the connecting portion and the support member.

  The tire acting force detection device of the present invention acts on a tire in a vehicle including a hub rotatably supported around an axle, a wheel connected to the hub, and a tire attached to the wheel. A tire acting force detection device for detecting a tire acting force, comprising: a connecting portion for connecting the hub and the wheel in the axle direction; and a detecting means for detecting a deformation amount of the connecting portion. The tire acting force is detected based on the deformation amount detected by the vehicle, and is further arranged in parallel with the connecting portion between the hub and the wheel in the axle direction, and the hub side or the wheel side A support member fixed to at least one of the support member, and the support member connects at least the hub and the wheel by the tire acting force to each other in the axle direction. When the load to be applied does not act, the hub side and the wheel side are brought into contact with each other, and the connecting portion and the support member are deformed in the axle direction by the load, whereby the axle direction of the hub and the wheel is changed. The ratio of the deformation amount in the axle direction of the support member to the change amount of the load when the load is small is the axle ratio of the support member to the change amount of the load when the load is large. It is characterized by being larger than the ratio of the amount of deformation in the direction.

  In the tire acting force detection device of the present invention, the support member includes a first support member component and a second support member component that are arranged in different regions in the axle direction and have different rigidity. The ratio of the deformation amount of the support member in the axle direction to the change amount of the load when the load is small is the ratio of the deformation amount of the support member in the axle direction to the change amount of the load when the load is large. It is characterized by being larger than

  In the tire acting force detection device of the present invention, the ratio of the rigidity of the support member to the rigidity of the connection portion in the deformation in the axle direction is the support for the rigidity of the connection portion in a bending deformation in a direction orthogonal to the axle direction. It is characterized in that it is larger than the rigidity ratio of the members.

  In the tire acting force detection device of the present invention, a plurality of circumferentially spaced intervals are arranged, and a first fastening portion fastened to the hub and a plurality of circumferentially spaced intervals are arranged, and each is fastened to the wheel. A second fastening portion, and the connecting portion connects the first fastening portion and the second fastening portion in the axle direction, thereby passing the first fastening portion and the second fastening portion. The hub and the wheel are connected in the axle direction, and the first fastening portion and the second fastening portion are alternately arranged in the circumferential direction.

  A tire acting force detection device according to the present invention includes a connection portion that connects a hub and a wheel in an axle direction, and detection means that detects a deformation amount of the connection portion, and is based on the deformation amount detected by the detection means. A tire working force is detected, and further, a support member is provided in parallel with the connecting portion between the hub and the wheel in the axle direction, and is fixed to one of the hub side or the wheel side and faces the other in the axle direction. .

  When a load that causes the hub and the wheel to approach each other in the axle direction due to the tire acting force acts and the connecting portion is deformed in the axle direction, the gap in the axle direction between the support member and the other is reduced. When the load is small, the support member is separated from the other, the connection portion supports the load, and when the load is large, the support member abuts the other, and the connection portion and the support member To support the load. As described above, when the load is large, the support member comes into contact with the other, and the connection portion and the support member support the load, so that excessive stress acts on the connection portion or excessive deformation occurs. While suppressing this, it is possible to reduce the rigidity of the connecting portion and improve the measurement accuracy of the tire acting force.

FIG. 1 is a diagram showing a cross section in the axle direction of a first embodiment of a tire acting force detection apparatus according to the present invention. FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 showing the configuration of the first embodiment of the tire acting force detection device according to the present invention. FIG. 3 is a Y view of FIG. 2 showing details of the configuration of the sensor plate in the first embodiment of the tire acting force detection device according to the present invention. FIG. 4 is a diagram showing a sensor plate when an overturning moment is applied in the first embodiment of the tire acting force detection apparatus according to the present invention. FIG. 5 is a diagram showing a sensor plate when an overturning moment and a rotational torque are applied in the first embodiment of the tire acting force detection apparatus according to the present invention. FIG. 6 is a diagram for explaining the shapes of the sensing unit and the overload prevention unit of the first embodiment of the tire acting force detection device according to the present invention. FIG. 7 is a diagram showing a configuration of a sensor plate according to a first modification of the first embodiment of the tire acting force detection device according to the present invention. FIG. 8 is a diagram showing a configuration of a sensor plate of a second modification of the first embodiment of the tire acting force detection apparatus according to the present invention. FIG. 9 is a diagram showing a configuration of a sensor plate of the second embodiment of the tire acting force detection device according to the present invention.

  EMBODIMENT OF THE INVENTION Below, it demonstrates in detail, referring drawings for one Embodiment of the tire action force detection apparatus concerning this invention. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

(First embodiment)
The first embodiment will be described with reference to FIGS. 1 to 6. The present embodiment relates to a tire acting force detection device that detects a tire acting force acting on a tire in a vehicle including a hub, a wheel connected to the hub, and a tire attached to the wheel. FIG. 1 is a diagram showing a cross section in the axle direction of a first embodiment of a tire acting force detection device according to the present invention, and FIG. 2 is a diagram of A- FIG. 1 showing the configuration of the tire acting force detection device according to this embodiment. FIG. 3 is a cross-sectional view taken along the line A, and FIG. 3 is a Y view of FIG. However, in FIG. 3, the rotation side circuit unit 30 of FIG. 2 described later is omitted.

  In FIG. 1, the code | symbol 3 shows a hub. The hub 3 has a shaft portion 3a, a flange portion 3b, and a cylindrical portion 3c. The shaft portion 3a of the hub 3 has a cylindrical shape and is rotatably supported by a vehicle body (not shown) via a bearing (not shown). The hub 3 is supported coaxially with the axle X and can freely rotate around the axle X. The flange portion 3b is connected to the shaft portion 3a and has a disk shape with the axle X as the central axis. The cylindrical portion 3c is formed on the wheel side (the opposite side to the vehicle body side) in the axle direction of the flange portion 3b, and protrudes toward the wheel side. The cylindrical portion 3c is formed in a cylindrical shape having the axle X as a central axis.

  Although the vehicle has a plurality of axles, in the following description, the axle direction refers to the axle direction of the axle X shown in FIG. 1 unless otherwise specified. Similarly, the radial direction refers to a direction orthogonal to the axle X unless otherwise specified.

  The wheel 1 has a cylindrical shape, and a tire (not shown) is mounted on the outer peripheral portion. A brake rotor 2 and a sensor plate 4 are disposed between the hub 3 and the wheel 1. That is, the hub 3 and the wheel 1 are opposed to each other in the axle direction with the brake rotor 2 and the sensor plate 4 interposed therebetween.

  The brake rotor 2 has an annular shape and is disposed between the hub 3 and the sensor plate 4. The brake rotor 2 is fixed to the hub 3 so as to rotate integrally with the hub 3 and constitutes a disc brake that brakes the vehicle together with a brake caliper 17 described later.

  The sensor plate 4 includes a wheel side plate (second fastening portion) 4b fastened to the wheel 1, a hub side plate (first fastening portion) 4c fastened to the hub 3, a wheel side plate 4b and a hub side plate 4c. Are connected to each other in the axle direction, and a rotation side circuit unit 30 is provided. The sensor plate 4 has a strength that can withstand running of the vehicle.

  As shown in FIG. 2, the wheel side plate 4b and the hub side plate 4c each have a sector shape. A plurality of wheel side plates 4b are arranged at intervals in the circumferential direction. Similarly, a plurality of hub side plates 4c are arranged at intervals in the circumferential direction. Further, the wheel side plates 4b and the hub side plates 4c are alternately arranged in the circumferential direction. In other words, the arrangement area of one wheel side plate 4b is sandwiched in the circumferential direction by the arrangement area of the hub side plate 4c, and the arrangement area of one hub side plate 4c is surrounded by the arrangement area of the wheel side plate 4b. It is sandwiched in the direction. The sensing unit 4a connects the wheel side plate 4b and the hub side plate 4c arranged in the adjacent regions in the circumferential direction in this way in the axle direction.

  As shown in FIG. 3, the sensing part 4a has a beam part 4m, a joint part 4n with the wheel side plate 4b, and a joint part 4p with the hub side plate 4c. The beam portion 4m is formed in a plate shape and extends parallel to the axle direction. The cross-sectional shape of the beam portion 4m in the direction orthogonal to the axle X is a rectangle. The long side of the cross section of the beam portion 4m is parallel to the radial direction, and the short side is orthogonal to the radial direction. In other words, the beam portion 4m is a plate-like member whose thickness direction is orthogonal to the radial direction. The joint portion 4n is provided at one end in the axle direction of the beam portion 4m, and the joint portion 4p is provided at the other end in the axle direction. The sensing part 4a connects the wheel side plate 4b and the hub side plate 4c in the axle direction by fixing the joint part 4n to the wheel side plate 4b and fixing the joint part 4p to the hub side plate 4c. . That is, the sensing unit 4a connects the hub 3 and the wheel 1 in the axle direction via the wheel side plate 4b and the hub side plate 4c by connecting the wheel side plate 4b and the hub side plate 4c in the axle direction. ing.

  The sensing unit 4a connects both ends in the circumferential direction of the wheel side plate 4b to end portions in the circumferential direction of different hub side plates 4c. In other words, one end of the wheel side plate 4b in the circumferential direction is connected to one of the two adjacent hub side plates 4c, and the other end in the circumferential direction of the wheel side plate 4b is connected to the other of the hub side plate 4c. Yes. Therefore, the two hub side plates 4c adjacent in the circumferential direction are connected via the sensing unit 4a and the wheel side plate 4b. Further, both ends in the circumferential direction of the hub side plate 4c are connected to end portions in the circumferential direction of different wheel side plates 4b by the sensing portions 4a. That is, one end in the circumferential direction of the hub side plate 4c is connected to one of the two adjacent wheel side plates 4b, and the other end in the circumferential direction of the hub side plate 4c is connected to the other of the wheel side plate 4b. . Therefore, the two wheel side plates 4b adjacent in the circumferential direction are connected via the sensing unit 4a and the hub side plate 4c.

  As described above, the wheel-side plates 4b and the hub-side plates 4c that are alternately arranged in the circumferential direction are connected to each other by the sensing unit 4a, whereby the integrated sensor plate 4 is configured. Therefore, as many sensing units 4a as the total number of wheel side plates 4b and hub side plates 4c are arranged. In the present embodiment, four wheel side plates 4b and four hub side plates 4c are provided, and eight sensing units 4a are arranged. The wheel side plates 4b are arranged at equal intervals of 90 degrees in the circumferential direction, and the hub side plates 4c are also arranged at equal intervals of 90 degrees in the circumferential direction. Further, the wheel side plate 4b and the hub side plate 4c are arranged with a phase shifted by 45 degrees. That is, the wheel side plate 4b and the hub side plate 4c are alternately arranged at equal intervals of 45 degrees. Thus, the wheel plate 4b and the hub plate 4c are alternately arranged in the circumferential direction, so that the sensor plate 4 can be reduced in weight.

  The wheel side plate 4b and the hub side plate 4c are connected by the sensing unit 4a in a state of being separated from each other in the axle direction, and a force is applied between the wheel side plate 4b and the hub side plate 4c via the sensing unit 4a. And moments are transmitted to each other.

  The sensing unit 4a functions as both a deformable member that detects a tire acting force based on the deformation and a transmission member that transmits force and moment between the wheel 1 and the hub 3. From the viewpoint of detecting the tire acting force, the sensing unit 4a may be singular. For example, the sensing unit 4a may be a single beam-shaped member having the axle X as the central axis. On the other hand, from the viewpoint of transmitting force between the wheel 1 and the hub 3, it is preferable that there are a plurality of sensing units 4 a, for example, a structure of four or more beams arranged in the circumferential direction. preferable. In addition, the cross-sectional shape of the sensing unit 4a can be a circle, an ellipse, a quadrangle (for example, a rectangle), a polygon, or the like, and may be hollow or solid. In the present embodiment, the sensing unit 4a is eight solid rectangles.

  In order to ensure the strength against the input of moment, the position of the sensing unit 4a is arranged on the outer side of the sensor plate 4 in the radial direction. Since the tire has a larger diameter than the sensor plate 4, the load applied to the sensing unit 4 a due to the tire acting force may be large, but the sensing unit 4 a is disposed on the outer side in the radial direction of the sensor plate 4. Thus, it is possible to accurately measure the tire acting force while securing an appropriate strength of the sensor plate 4.

  As shown in FIG. 1, the wheel side plate 4b is formed with a through hole 4j that passes through the wheel side plate 4b in the axle direction. A wheel contact surface 4h is formed at a portion of the wheel side plate 4b that faces the wheel 1 in the axle direction. The wheel contact surface 4h is formed in a shape corresponding to the shape of the portion of the wheel 1 that faces the wheel contact surface 4h. Specifically, the wheel contact surface 4h is formed in a planar shape orthogonal to the axle direction. That is, the wheel 1 and the wheel contact surface 4h are in contact with each other on a surface orthogonal to the axle X. The wheel side plate 4b and the wheel 1 are screwed into the wheel fixing bolt 7 and the wheel fixing bolt 7 inserted into the through hole 1a formed in the wheel 1 in the axle direction and the through hole 4j of the wheel side plate 4b. Fastened with the wheel fixing nut 8.

  A wheel coaxial protrusion 4e is formed at the radially inner end of the wheel side plate 4b. The wheel coaxial protrusion 4e protrudes toward the wheel side, and an outer peripheral surface thereof is formed in an arc shape centered on the axle X. By fitting the inner peripheral surface of the wheel 1 to the outer peripheral surface of the wheel coaxial protrusion 4e, the wheel 1 is axially aligned (positioning in the radial direction).

  The hub side plate 4c is formed with a through hole 4k that passes through the hub side plate 4c in the axle direction. A brake rotor contact surface 4i is formed in a portion of the hub side plate 4c that faces the brake rotor 2 in the axle direction. The brake rotor contact surface 4i is formed in a shape corresponding to the shape of the portion of the brake rotor 2 that faces the brake rotor contact surface 4i. Specifically, the brake rotor contact surface 4i is formed in a planar shape orthogonal to the axle direction. That is, the brake rotor 2 and the brake rotor contact surface 4i are in contact with each other on a surface orthogonal to the axle X. The hub 3 is formed with a through hole 3d in the axle direction, and the brake rotor 2 is formed with a through hole 2a in the axle direction. The hub 3, the brake rotor 2, and the hub side plate 4c are formed by a brake rotor fixing bolt 5 inserted into the through holes 3d, 2a, and 4k, and a brake rotor fixing nut 6 screwed into the brake rotor fixing bolt 5. It is concluded.

  A hub coaxial protrusion 4f is formed at the radially inner end of the hub side plate 4c. The inner peripheral surface of the hub coaxial protrusion 4 f that faces the axle X in the radial direction is formed in an arc shape having a diameter corresponding to the outer diameter of the cylindrical portion 3 c of the hub 3. Axis alignment when the sensor plate 4 is fitted into the cylindrical portion 3c of the hub 3 is performed by the hub coaxial projection 4f.

  Since the wheel side plate 4b is fastened to the wheel 1 and the hub side plate 4c is fastened to the hub 3, the tire acting force (grounding force) acting on the tire (not shown) is transmitted from the wheel 1 to the wheel side plate 4b, the sensing unit. 4a is transmitted to the hub 3 via the hub side plate 4c.

  As shown in FIG. 2, the through hole 4 j of the wheel side plate 4 b and the through hole 4 k of the hub side plate 4 c are arranged with a phase shift in the circumferential direction, and the wheel fixing bolt 7 and the brake rotor fixing bolt 5 are arranged. Interference with is suppressed. Specifically, the through hole 4j of the wheel side plate 4b and the through hole 4k of the hub side plate 4c are arranged with a phase shift of 45 degrees (phase angle of 45 degrees). By suppressing interference between the wheel fixing bolt 7 and the brake rotor fixing bolt 5, an increase in the width of the sensor plate 4 in the axle direction is suppressed.

  When the tire traveling direction is the x-axis, the axle direction is the y-axis, and the vertical direction (the direction orthogonal to the x-axis and y-axis) is the z-axis, the tire has a longitudinal force Fx, a lateral force Fy, and a vertical force. The tire acting forces of Fz, moment due to lateral force Fy (hereinafter referred to as “over-turning moment”) Mx, rotational torque My, and self-aligning torque Mz are applied. Here, since the diameter of the sensor plate 4 is smaller than the diameter of the tire, the stress generated in the sensor plate 4 due to the input of moment becomes large. Of the six component forces, the stress due to the overturning moment Mx is particularly large. In the sensor plate 4 of the present embodiment, for example, the stress due to the overturning moment Mx (or the stress due to the self-aligning torque Mz) is about twice that of the stress due to the rotational torque My, and other forces (front and rear) Compared with the stress caused by the force Fx, the lateral force Fy, and the vertical force Fz), the magnitude is about ten times.

  As a sensor for measuring the tire acting force, as shown in FIG. 2, the sensing unit 4a is provided with a sensor (detecting means) 4d. The sensor 4d is a sensor that reacts to a load (stress) acting on the sensing unit 4a or deformation of the sensing unit 4a due to the load, and an output changes in accordance with the tire ground contact force. For example, a strain gauge or a piezoelectric element can be used as the sensor 4d. In the following description, a case where the sensor 4d is a strain gauge will be described. The strain gauge as the sensor 4d is fixed to the sensing unit 4a so as to be deformed (expanded) with the deformation of the sensing unit 4a. Specifically, two sensors 4d are fixed to a surface (surface along the radial direction) orthogonal to the circumferential direction in each sensing unit 4a. Thereby, if the sensing part 4a deform | transforms, the distortion amount (deformation amount) can be detected based on the detection result of the sensor 4d. In the present embodiment, two sensors 4d are arranged in each sensing unit 4a, a total of 16 sensors, but the number of sensors 4d is not limited to this, and the measurement system and mounting space are taken into consideration. Can be increased or decreased.

  As shown in FIGS. 1 and 2, a rotation side circuit unit 30 is disposed on the outer periphery of the sensor plate 4. The rotation side circuit unit 30 includes a rotation side holder 10, a transmission circuit 9, a power reception coil 11, a signal transmission antenna 12, and a sensor wiring 13. The rotation-side holder 10 has a cylindrical shape with the axle X as a central axis, and a transmission circuit 9, a power reception coil 11, a signal transmission antenna 12, and a sensor wiring 13 are arranged inside. The rotation side holder 10 is fixed to the outer peripheral portions of the wheel side plate 4b and the hub side plate 4c, and rotates integrally with the wheel side plate 4b and the hub side plate 4c. The transmission circuit 9 is operated by electric power supplied via the power receiving coil 11, and is electrically connected to each sensor 4d and the signal transmission antenna 12. The sensor wiring 13 connected to each sensor 4d passes through the rotation side holder 10 and is connected to the transmission circuit 9, and the distortion amount of each sensor 4d is acquired by the transmission circuit 9. The acquired signal indicating the amount of distortion of each sensor 4d is transmitted from the signal transmission antenna 12 to the signal reception antenna 16 described later. The rotation-side holder 10 is made of a material such as resin that does not affect signal transmission. Built in state.

  By configuring the sensor plate 4 as described above, the sensor plate 4 can be removed simply by removing the wheel fixing nut 8 and the brake rotor fixing nut 6. Therefore, there is compatibility between vehicles in which the number of bolts matches the pitch, and attachment and removal can be easily performed. Further, the sensor plate 4 can be attached to the vehicle without requiring modification of the vehicle.

  A brake caliper 17 is fixed near the sensor plate 4 in the vehicle body. The brake caliper 17 constitutes a disc brake that brakes the vehicle together with the brake rotor 2, and is disposed on the radially outer side of the brake rotor 2. A fixed circuit portion 31 is fixed to the brake caliper 17. The fixed circuit unit 31 includes the fixed holder 14, the power transmission coil 15, and the signal receiving antenna 16. The fixed side holder 14 is disposed on the radially outer side of the rotary side holder 10 and faces the rotary side holder 10 in the radial direction. The fixed-side holder 14 is formed in an arc shape having the axle X as the central axis so that the radial gap with the rotation-side holder 10 is constant in the circumferential direction. As shown in FIG. 1, a power transmission coil 15 and a signal reception antenna 16 are arranged inside the fixed side holder 14. The fixed side holder 14 is formed of a material such as resin that does not affect signal reception, and the power transmission coil 15 and the signal reception antenna 16 are subjected to waterproof processing such as an insert and an adhesive mold on the fixed side holder 14. Built in. In addition, the attachment location of the fixed side circuit unit 31 is not limited to the brake caliper 17 and may be any component that does not rotate in conjunction with tire rotation in the vehicle.

  A receiving circuit 18 is electrically connected to the signal receiving antenna 16 of the fixed holder 14, and a signal indicating the amount of distortion of each sensor 4 d received by the signal receiving antenna 16 is controlled by the vehicle via the receiving circuit 18. Input to the computer 19. The vehicle control computer 19 is configured by a known microcomputer, and detects (calculates) the tire acting force based on a signal indicating the strain amount of each sensor 4d that is input. The vehicle control computer 19 is connected to a position sensor (not shown) that detects the rotational angle position of the tire. The vehicle control computer 19 calculates the tire acting force based on the rotation angle position of the tire detected by the position sensor and the stress acting on each sensing unit 4a calculated based on the detection result of each sensor 4d. .

  The sensing unit 4a of the present embodiment has a rectangular shape that is long in the radial direction and short in the circumferential direction in the cross-sectional shape. Thus, the length in the thickness direction (length in the circumferential direction) for bending is shorter than the length in the width direction (length in the radial direction) for bending, which is sufficient for the load in the axle direction. While ensuring a sufficient cross-sectional area, the amount of deformation when bending stress due to the rotational torque My is applied is increased to improve the measurement accuracy of the rotational torque My.

  The tire acting force detection device 1-1 according to the present embodiment includes a sensor plate 4, a rotation side circuit unit 30, a fixed side circuit unit 31, a reception circuit 18, and a vehicle control computer 19.

  Here, as in the case of the tire acting force detection device 1-1 of the present embodiment, when the tire acting force is detected based on the deformation of the sensing portion (connecting portion) 4a that connects the hub 3 and the wheel 1, the tire action is detected. In order to improve force measurement accuracy, it is advantageous that the sensing unit 4a is easily deformed. In other words, a larger deformation amount (distortion amount) of the sensing unit 4a with respect to the same tire acting force is advantageous in terms of improving the measurement accuracy of the tire acting force. For example, if the rigidity of the sensing unit 4a is reduced, such as by reducing the cross-sectional area of the sensing unit 4a, the measurement accuracy of the tire acting force can be improved. However, if the rigidity of the sensing unit 4a is lowered, excessive stress may act on the sensing unit 4a or excessive deformation may occur in the sensing unit 4a.

  In the tire acting force detection device 1-1 of the present embodiment, an overload prevention unit (support member) 4g that suppresses an excessive load from acting on the sensing unit 4a is provided. As shown in FIG. 1, the overload prevention part 4 g is fixed to the vehicle body side (the side opposite to the wheel side in the axle direction) of the wheel side plate 4 b and protrudes toward the brake rotor 2 in the axle direction. In other words, the overload prevention portion 4g is disposed in parallel with the sensing portion 4a between the hub 3 and the wheel 1 in the axle direction, and the base end portion of the overload prevention portion 4g is fixed to the wheel side plate 4b. The front end portion protrudes toward the hub 3 and faces the brake rotor 2 on the hub 3 side in the axle direction. The overload prevention portion 4g is provided at the radially outer end of the wheel side plate 4b.

  As shown in FIG. 2, the cross-sectional shape of the overload preventing portion 4g in the direction orthogonal to the axle direction is a rectangle, and specifically, a rectangle having a long side in the radial direction and a short side in the circumferential direction. The overload prevention part 4g is arrange | positioned in the center part of the circumferential direction in the wheel side plate 4b. Therefore, the overload prevention part 4g is located in an intermediate part between the sensing parts 4a adjacent to each other in the circumferential direction.

  FIG. 3 shows the sensor plate 4 in a state where the lateral force Fy is not acting on the tire (the overturning moment Mx is not generated). In a state where the overturning moment Mx is not generated, the overload preventing portion 4g and the brake rotor 2 are separated from each other. The initial value (the magnitude of the state in which no overturning moment Mx is generated) of the clearance Δt between the overload prevention portion 4g and the brake rotor 2 in the axle direction is set to be within the deformation displacement due to the input of the overturning moment Mx. Yes. That is, when the overturning moment Mx is 0, the gap Δt is a positive value, and the overload preventing portion 4g and the brake rotor 2 are separated in the axle direction.

  When an overturning moment Mx is generated and an axial load is applied to the wheel side plate 4b toward the hub side plate 4c, the overload preventing portion 4g and the brake rotor 2 approach in the axle direction (overturning moment). Deformation displacement occurs due to the input of Mx), and the gap Δt decreases from the initial value. When the overturning moment Mx increases and a deformation displacement corresponding to the initial value of the gap Δt occurs (the gap Δt becomes 0), the overload preventing portion 4g comes into contact with the brake wheel 2. The deformation displacement at this time is a value smaller than the maximum value of the deformation displacement due to the input of the overturning moment Mx. That is, the overload preventing portion 4g contacts the brake rotor 2 at an overturning moment Mx smaller than the designed maximum value. As a result, as will be described later, the overload preventing portion 4g can be brought into contact with the brake rotor 2 only when a load due to the input of the overturning moment Mx is applied, and the stress in the axle direction can be relieved. When only My acts, the overload prevention unit 4g and the brake rotor 2 are separated from each other, so that the measurement accuracy of the rotational torque My is not affected.

  FIG. 4 is a diagram showing the sensor plate 4 when the overturning moment Mx is applied. When the overturning moment Mx acts, a load in the axle direction toward the brake rotor 2 acts on the one wheel side plate 4b across the axle X, and the other wheel side plate 4b acts on the wheel side plate 4b from the brake rotor 2. A load in the direction of the axle that separates acts. Here, the load in the axle direction toward the brake rotor 2 is a load that brings the hub 3 and the wheel 1 closer to each other in the axle direction. In FIG. 4, reference numeral 20 indicates a load in the axle direction toward the brake rotor 2 (hereinafter, simply referred to as “load 20 in the axle direction”).

  Among each sensing part 4a, compressive stress acts on sensing part 4a which supports wheel side plate 4b where load 20 of an axle direction acts. The sensing part 4a on which the compressive stress is applied contracts in the axle direction, and the wheel side plate 4b and the hub side plate 4c approach the axle direction. As a result, the gap Δt between the overload preventing portion 4g and the brake rotor 2 in the axle direction is reduced. That is, the sensing portion 4a is deformed in the axle direction by the load 20 in the axle direction (the load that brings the hub 3 and the wheel 1 close to each other in the axle direction), so that the clearance in the axle direction between the overload prevention portion 4g and the brake rotor 2 is reduced. Δt decreases.

  The gap Δt decreases as the overturning moment Mx increases, and becomes zero when the overturning moment Mx exceeds a predetermined value. That is, when the overturning moment Mx is equal to or greater than a predetermined value, the overload preventing portion 4g contacts the brake rotor 2 and receives the load 20 in the axle direction due to the overturning moment Mx. That is, when the overturning moment Mx is small and the load 20 in the axle direction is small, the overload prevention portion 4g is separated from the brake rotor 2, and the sensing portion 4a supports the load 20 in the axle direction, and the overturning moment When Mx is large and the load 20 in the axle direction is large, the overload prevention portion 4g contacts the brake rotor 2, and the sensing portion 4a and the overload prevention portion 4g support the load 20 in the axle direction. This reduces the load acting on the sensing unit 4a due to the particularly large overturning moment Mx out of the six component forces of the tire acting force, and causes excessive stress or excessive deformation to the sensing unit 4a. Can be suppressed.

  The overload preventing portion 4g is separated from the brake rotor 2 when the overturning moment Mx is less than a predetermined value or when the overturning moment Mx is not acting. In this state, the overload prevention unit 4g does not affect the measurement accuracy of the tire acting force such as the overturning moment Mx and the rotational torque My. For example, when the overturning moment Mx does not act on the tire and only the rotational torque My acts, the overload prevention unit 4g does not affect the measurement accuracy of the rotational torque My.

  Further, as will be described below with reference to FIGS. 5 and 6, the overload prevention portion 4 g has a small influence on the measurement accuracy of the rotational torque My even when it is in contact with the brake rotor 2. It is configured. By increasing the cross-sectional shape of the overload prevention part 4g in the radial direction, the ability to relieve stress due to the input of the overturning moment Mx is increased and the rotational torque My is measured due to the difference in the characteristics of the tensile compression stiffness and bending stiffness. The influence on accuracy can be reduced. FIG. 5 is a diagram showing the sensor plate 4 when the overturning moment Mx and the rotational torque My are applied, and FIG. 6 is a diagram for explaining the shapes of the sensing unit 4a and the overload prevention unit 4g.

  In FIG. 5, reference numeral 21 indicates a circumferential load (hereinafter simply referred to as “circumferential load 21”) acting on the wheel side plate 4 b by the rotational torque My. When both the axial load 20 and the circumferential load 21 are acting on the wheel side plate 4b, if the overload prevention part 4g contacts the brake rotor 2 due to the axial load 20, the overload prevention part 4g Will receive not only the axial load 20 but also the circumferential load 21. Thereby, compared with the case where the overload prevention part 4g is not provided, the stress of the axial direction in a sensing part 4a and a bending direction becomes a different value, respectively.

First, axial rigidity and stress will be described. With respect to the input of the overturning moment Mx, the compression is tensile in the sensing unit 4a and the overload prevention unit 4g, so the stress is inversely proportional to the tensile compression stiffness. That is, if the Young's modulus E is the same, the stress is inversely proportional to the cross-sectional area. In the present embodiment, when the overload prevention portion 4g contacts the brake rotor 2, the cross-sectional area that supports the axial load 20 is larger than when the overload prevention portion 4g does not contact the brake rotor 2. To increase. The tensile compression rigidity of the overload preventing portion 4g can be expressed by EA (E: Young's modulus, A: cross-sectional area in a direction orthogonal to the axle direction). As shown in FIG. 6, when the cross-sectional shape of the overload prevention part 4g is a rectangle whose radial length is b and circumferential length is h, the cross-sectional area A of the overload prevention part 4g is It is represented by Formula (1).
A = bh (1)

Similarly, _assuming that the cross-sectional area of the sensing unit 4a is A _s and the Young's modulus is E, which is the same as that of the overload prevention unit 4g, the tensile and compressive rigidity of the sensing unit 4a is EA _s . Length b _s of a cross section of the sensing portion 4a _radially, when a rectangular circumferential length h _s, the cross-sectional area A _s of the sensing portion 4a is represented by the following formula (2).
A _s = b _{sh s} (2)

When the overload prevention part 4g contacts the brake rotor 2, the stress due to the input of the overturning moment Mx is reduced as compared with the case where the overload prevention part 4g is not provided. With respect to the stress in the axle direction of the sensing unit 4a by the input of the overturning moment Mx, the stress when the overload prevention unit 4g is in contact with the brake rotor 2 with respect to the stress when the overload prevention unit 4g is not provided The ratio (hereinafter simply referred to as “axle direction stress ratio P1”) is expressed by the following equation (3).
P1 = (A _s / (A _s + A)) (3)
That is, when the overload prevention part 4g receives the load 20 in the axle direction, the stress is reduced to (A _s / (A _s + A)) times. Thereby, compared with the case where the overload prevention part 4g is not provided, the stress which acts on the sensing part 4a and the deformation amount of the sensing part 4a are reduced.

Next, bending rigidity and stress (amount of strain) will be described. When the overload prevention part 4g contacts the brake rotor 2, the bending rigidity also changes. The bending rigidity of the overload preventing portion 4g is represented by EI (E: Young's modulus, I: secondary moment of section). In the cross section of the overload preventing portion 4g, the length in the width direction with respect to the bending is b, and the length in the thickness direction with respect to the bending is h. Therefore, the cross-sectional secondary moment I is expressed by the following formula (4).
^{I = bh 3/12 (4} )

Similarly, cross-sectional secondary moment _{I s} of the sensing portion 4a is represented by the following formula (5).
^{_{I s = b s h s 3}} /12 (5)

When the rotational torque My is input, the sensing unit 4a and the overload prevention unit 4g are bent, so the stress (strain amount) is inversely proportional to the bending stiffness, but the Young's modulus E is a constant value, so the stress is a cross section. It will be inversely proportional to the second moment. When the overload prevention part 4g contacts the brake rotor 2, the stress (strain amount) due to the input of the rotational torque My is reduced as compared with the case where the overload prevention part 4g is not provided. In the bending stress (strain amount) of the sensing unit 4a by the input of the rotational torque My, the overload prevention unit 4g contacts the brake rotor 2 against the stress (strain amount) when the overload prevention unit 4g is not provided. The stress (strain amount) ratio (hereinafter simply described as “bending stress ratio P2”) is expressed by the following formula (6).
P2 = _Is / ( _Is + I) (6)
That is, the stress (strain amount) is reduced to (I _s / (I _s + I)) times by the overload preventing portion 4 g receiving the circumferential load 21.

In the present embodiment, the overload prevention unit 4g is configured so that the stress due to the input of the overturning moment Mx is relieved and the influence on the measurement accuracy of the rotational torque My is minimal. Specifically, overload prevention unit 4g, the ratio of the stiffness EA of overload prevention unit 4g for stiffness EA _s of the sensing portion 4a in the axle direction of the deformation (hereinafter, simply referred to as "rigidity ratio of the axle direction") but the direction perpendicular to the axle direction (in particular, a direction perpendicular to the radial direction) the ratio of the stiffness EI of the overload prevention unit 4g for rigidity EI _s of the sensing portion 4a of the bending deformation (hereinafter, simply as "flexural rigidity ratio" It is configured to be larger than (describe).

First, when the rigidity ratio in the axle direction is S1, the rigidity ratio S1 in the axle direction is expressed by the following formula (7).
_{S1 = EA / EA s = A} / A s (7)

When the above equation (3) is transformed using the above equation (7), the stress ratio P1 in the axle direction is expressed by the following equation (8).
P1 = 1 / (1 + S1) (8)

Next, when the bending rigidity ratio is S2, the bending rigidity ratio S2 is expressed by the following formula (9).
S2 = EI / EI _s = I / I _s (9)

When the above equation (6) is deformed using the above equation (9), the bending stress ratio P2 is expressed by the following equation (10).
P2 = 1 / (1 + S2) (10)

  As can be seen from the above equations (8) and (10), when the rigidity ratio S1 in the axle direction is larger than the bending rigidity ratio S2, the bending stress ratio P2 is larger than the stress ratio P1 in the axle direction. Become. In other words, when the rigidity ratio S1 in the axle direction is larger than the bending rigidity ratio S2, the reduction ratio of the bending stress (strain amount) is smaller than the reduction ratio of the stress in the axle direction. That is, the degree of decrease in bending stress is smaller than the degree of decrease in stress in the axle direction when the overload prevention portion 4g abuts against the brake rotor 2, and the influence on the measurement accuracy of bending stress is It becomes smaller compared to the effect on the measurement accuracy of the stress in the direction.

Here, in the case where the cross-sectional shapes of the sensing unit 4a and the overload prevention unit 4g are rectangular as in the present embodiment, the conditions for the rigidity ratio S1 in the axle direction to be greater than the bending rigidity ratio S2 will be described. From the above equations (7) and (9), the difference between the rigidity ratio S1 in the axle direction and the bending rigidity ratio S2 is the following expression (11).
S1-S2 = A / A _s -I / I _s (11)
Substituting the above formula (1), formula (2), formula (4), and formula (5) into the above formula (11), the following [Formula 1] is obtained.

From the above [Equation 1], if the length h in the thickness direction of the overload prevention portion 4g is smaller than the length h _s in the thickness direction of the sensing portion 4a, the above [Equation 1] becomes a positive value. That is, it can be seen that the rigidity ratio S1 in the axle direction is larger than the bending rigidity ratio S2. That is, when each of the overload prevention unit 4g and the sensing unit 4a is a beam portion having a rectangular cross section, the length h in the thickness direction of the overload prevention unit 4g is set to the length h _s in the thickness direction of the sensing unit 4a. By making the comparison smaller, the rigidity ratio S1 in the axle direction can be made larger than the bending rigidity ratio S2, and the bending stress ratio P2 can be made larger than the stress ratio P1 in the axle direction.

  As will be described below, the same applies even when the Young's modulus of the overload prevention unit 4g and the Young's modulus of the sensing unit 4a are different.

If the Young's modulus of the overload prevention unit 4g E, the Young's modulus of the sensing portion 4a was E _s, the stress ratio P1 of the axle direction is represented by the following formula (12).
_{P1 = E s A s / (} E s A s + EA) (12)
The bending stress ratio P2 is expressed by the following formula (13).
_{P2 = E s I s / (} E s I s + EI) (13)

Further, the rigidity ratio S1 and the bending rigidity ratio S2 in the axle direction are expressed by the following expressions (14) and (15), respectively.
_{S1 = EA / E s A s} (14)
_{S2 = EI / E s I s} (15)

  If the above equation (12) is modified using the above equation (14), the stress ratio P1 in the axle direction can be expressed by the above equation (8). Moreover, if the said Formula (13) is deform | transformed using the said Formula (15), the bending stress ratio P2 can be represented by the said Formula (10). Further, the difference between the rigidity ratio S1 in the axle direction and the bending rigidity ratio S2 from the expressions (14) and (15) and the expressions (1), (2), (4), and (5). Is expressed by the following [Equation 2].

From the above Equation 2, even when the Young's modulus E Young's modulus E _s and overload prevention unit 4g of the sensing portion 4a is different, the length h in the thickness direction of the overload prevention unit 4g is, the sensing unit If it is smaller than the length h _s in the thickness direction of 4a, it can be seen that the rigidity ratio S1 in the axle direction is larger than the bending rigidity ratio S2. In other words, the length h in the thickness direction of the overload prevention unit 4g, by small compared to the length h _s in the thickness direction of the sensing portion 4a, as compared to the rigidity ratio S2 flexural rigidity ratio S1 of the axle direction Thus, the bending stress ratio P2 can be made larger than the stress ratio P1 in the axle direction.

Here, as an example, the width direction length b = 20 mm of the cross-sectional shape of the overload prevention portion 4g, the thickness direction length h = 1 mm, the width direction length b _{s of the} sensing portion 4a = 20 mm, the thickness direction length The influence of the stress (strain amount) on the overturning moment Mx and the rotational torque My when the length h _s = 5 mm is calculated. The stress ratio P1 and bending stress ratio P2 in the axle direction are as follows.
P1 = (A _s / (A _s + A)) = 0.83
P2 = ( _Is / ( _Is + I)) = 0.99
That is, the stress with respect to the input of the overturning moment Mx is reduced by 17%, and the strain amount with respect to the input of the rotational torque My is reduced by 1%. That is, the stress due to the input of the overturning moment Mx is relieved, and the influence on the measurement accuracy of the rotational torque My is minimal. Therefore, even when the overload prevention portion 4g is in contact with the brake rotor 2, the tire is based on the detection result of the sensor 4d with almost the same accuracy as when the overload prevention portion 4g is not in contact with the brake rotor 2. Rotational torque My acting on can be measured.

  As described above, in the tire acting force detection device 1-1 of the present embodiment, the load is increased with respect to the load (load 20 in the axle direction) due to the overturning moment Mx that generates the largest stress in the sensing unit 4a. In some cases, an overload prevention unit 4g is provided to support the load together with the sensing unit 4a. Thereby, it is suppressed that an excessive stress acts on the sensing part 4a or an excessive deformation occurs. Thereby, since there is a margin in strength, it is possible to improve the reliability of the tire acting force detector 1-1, downsize the sensor plate 4, and improve the balance between measurement accuracy and strength.

  For example, even if the rigidity of the sensing unit 4a is the same, the load applied to the sensing unit 4a is reduced when the overload prevention unit 4g receives a load, so that the reliability of the tire acting force detection device 1-1 is improved. . In addition, the rigidity of the sensing unit 4a can be reduced (for example, the cross-sectional area can be reduced) as compared with the case where only the sensing unit 4a receives the load 20 in the axle direction due to the overturning moment Mx. Thereby, size reduction of the sensor plate 4 is attained. Since the sensing portion 4a can be made low in rigidity, the tire acting force including the overturning moment Mx is measured with high accuracy in the region of the relatively small overturning moment Mx until the overload preventing portion 4g contacts the brake rotor 2. can do.

  The overload preventing portion 4g is configured such that the rigidity ratio S1 in the axle direction is larger than the bending rigidity ratio S2. That is, the overload prevention part 4g has high rigidity with respect to the load 20 in the axle direction, can reduce the stress (distortion amount) in the axle direction generated in the sensing part 4a, and is rigid with respect to bending due to the load 21 in the circumferential direction. Therefore, the bending stress (amount of strain) generated in the sensing unit 4a is not greatly affected. As a result, even if the overload prevention part 4g is supporting the load 20 in the axle direction, the rotational torque My acting on the tire can be accurately detected based on the detection result of the sensor 4d.

  In the present embodiment, the sensor plate 4 is independent of the hub 3 and the wheel 1, but at least a part of the sensor plate 4 may be formed integrally with the hub 3 or the wheel 1. For example, the sensing unit 4a may be formed integrally with the hub 3. In other words, the sensor plate 4 includes a connection portion that connects the hub 3 and the wheel 1 in the axial direction, transmits a force between the hub 3 and the wheel 1, and a detection unit that detects deformation of the connection portion. It only has to be.

(First modification of the first embodiment)
A first modification of the first embodiment will be described. FIG. 7 is a diagram showing the configuration of the sensor plate 4 according to this modification. In the said 1st Embodiment, although the overload prevention part 4g was the same number as the sensing part 4a, the number of the overload prevention parts 4g is not limited to this. The number of overload prevention parts 4g can be freely set so that the balance between the stress due to the overturning moment Mx and the strain amount due to the rotational torque My satisfies the design criteria.

  For example, in this modification, three overload prevention parts 4g are arranged between the sensing parts 4a adjacent in the circumferential direction. Thereby, the stress of the sensing part 4a by the load 20 of the axle direction by the overturning moment Mx can be further reduced.

  As shown in FIG. 7, between the sensing parts 4a adjacent to each other in the circumferential direction, three overload prevention parts 4g are arranged adjacent to each other in the circumferential direction. The shape of the overload prevention portion 4g is the same as that of the overload prevention portion 4g of the first embodiment, and the cross-sectional shape thereof is b in the radial direction (width) and length (thickness) in the circumferential direction. Is h. The three overload prevention parts 4g are parallel to each other and arranged in the circumferential direction at equal intervals. Among the three sheets, the central overload prevention part 4g is located at an intermediate part between adjacent sensing parts 4a.

By providing three overload preventing portions 4g, the stress ratio P1 in the axle direction is expressed by the following equation (16).
P1 = A _s / (A _s + 3A) (16)

Moreover, the bending stress ratio P2 is represented by the following formula (17).
_{P2 = I s / (I s} + 3I) (17)

Similar to the first embodiment, the width b of the cross-sectional shape of the overload preventing portion 4g is 20 mm, the length h is 1 mm in the thickness direction, the length b _{s is} 20 mm in the width direction of the sensing portion 4a, When the length h _s in the thickness direction is 5 mm, the stress ratio P1 = 0.63 in the axle direction from the above equation (16), and the bending stress ratio P2 = 0.98 from the above equation (17). That is, the stress due to the overturning moment Mx is reduced by 37%, and the stress (strain amount) reduction due to the rotational torque My is only 2%. Therefore, it is possible to reduce the stress in the axle direction generated in the sensing unit 4a while minimizing the influence of the rotational torque My on the stress.

  Thus, when increasing the cross-sectional area A in the direction orthogonal to the axle direction in the overload prevention portion 4g, instead of increasing the thickness direction length (circumferential length) h of one overload prevention portion 4g. In addition, by increasing the number of overload prevention portions 4g, it is possible to relieve the stress in the axle direction while suppressing an increase in the degree of influence of the rotational torque My on the stress. When the cross-sectional area A of the overload prevention part 4g is increased three times, if the length h in the thickness direction of the overload prevention part 4g is tripled, the secondary moment I of the cross section is 27 times from the above formula (4). Will increase. On the other hand, if the number of overload prevention portions 4g is three without changing the length h in the thickness direction as in the present modification, the increase in the cross-sectional secondary moment I can be suppressed to three times. it can. That is, in order to reduce the secondary moment I of the cross section while ensuring a large cross sectional area A, a plurality of overload prevention portions 4g having a reduced length h in the thickness direction may be disposed.

  In this modification, the number of overload prevention parts 4g is different from that in the first embodiment, but the position of the overload prevention part 4g may be changed. As with the number of overload prevention portions 4g, the position of the overload prevention portion 4g is freely set so that the balance between the stress due to the overturning moment Mx and the amount of distortion due to the rotational torque My satisfies the design criteria. be able to.

(Second modification of the first embodiment)
A second modification of the first embodiment will be described. FIG. 8 is a diagram showing the configuration of the sensor plate 4 of this modification. In the first embodiment, the overload prevention portion 4g is fixed to one of the wheel side or the hub side (for example, the wheel side plate 4b), and when the load 20 in the axle direction is small, the other (for example, the brake rotor 2) When the load 20 in the axle direction is large, the load 20 abuts on the other side. Instead, the overload prevention portion 4g is separated from both the wheel side and the hub side when the load 20 in the axle direction is small. However, when the load 20 in the axle direction is large, the wheel side and the hub side may be brought into contact with each other.

  As shown in FIG. 8, the overload prevention part 41 of this modification is connected with the sensing part 4a and supported by the sensing part 4a. The overload prevention part 41 is arrange | positioned in the same position as the overload prevention part 4g of the said 1st Embodiment in the circumferential direction and radial direction, for example. Moreover, the cross-sectional shape of the direction orthogonal to the axle direction of the overload prevention part 41 can be made into the same shape as the overload prevention part 4g of the said 1st Embodiment. The overload prevention portion 41 is disposed in parallel with the sensing portion 4a between the hub 3 and the wheel 1 in the axle direction, and the end on the wheel side faces the wheel side plate 4b in the axle direction, and the end on the vehicle body side Faces the brake rotor 2 in the axle direction.

  FIG. 8 shows the sensor plate 4 in a state where the lateral force Fy is not acting on the tire (the overturning moment Mx is not generated). In a state where the overturning moment Mx is not generated, the overload prevention portion 41 is separated from the brake rotor 2 and the wheel side plate 4b in the axle direction. The initial value (the magnitude of the state in which no overturning moment Mx occurs) of the clearance Δt between the overload prevention portion 41 and the brake rotor 2 in the axle direction is set to a size within the deformation displacement due to the input of the overturning moment Mx. Yes. Further, the gap in the axle direction between the overload prevention portion 41 and the wheel side plate 4b is set to the same size as the gap Δt in the axle direction between the overload prevention portion 41 and the brake rotor 2.

  The overload prevention part 41 and the sensing part 4a are connected by a connecting member 42. The connecting member 42 connects the overload prevention part 41 and the sensing part 4a in a direction orthogonal to the axle direction. The overload prevention part 41 is supported by the sensing part 4a via the connecting member 42, so that neither the wheel side plate 4b nor the brake rotor 2 is in contact with the wheel side plate 4b and the brake rotor 2. Can stand still in the gap.

  When the overturning moment Mx is generated and the load 20 in the axle direction toward the hub side plate 4c is applied to the wheel side plate 4b, the sensing portion 4a is deformed in the axle direction and the axle of the wheel 1 and the brake rotor 2 is The direction gap is reduced. Thereby, the gap Δt in the axle direction between the overload prevention portion 41 and the brake rotor 2 and the gap in the axle direction between the overload prevention portion 41 and the wheel side plate 4b are reduced. When the overturning moment Mx exceeds a predetermined value, the overload prevention part 41 and the wheel side plate 4b, the overload prevention part 41 and the brake rotor 2 come into contact with each other, and the overload prevention part 41 together with the sensing part 4a in the axle direction. A load 20 is received. This reduces the load acting on the sensing unit 4a due to the particularly large overturning moment Mx out of the six component forces of the tire acting force, and causes excessive stress or excessive deformation to the sensing unit 4a. Can be suppressed.

(Second Embodiment)
A second embodiment will be described with reference to FIG. In the second embodiment, only differences from the first embodiment will be described. FIG. 9 is a diagram showing the configuration of the sensor plate of the present embodiment.

  The overload prevention part 43 of the present embodiment is different from the overload prevention parts 4g, 41 of the first embodiment in that the overload prevention part 43 is connected to the hub side and the wheel at least when the load 20 in the axle direction does not act. It is the point that is in contact with each of the sides. Further, the ratio of the amount of deformation in the axle direction of the overload prevention unit 43 to the amount of change in the load 20 in the axle direction differs depending on whether the load 20 in the axle direction is small or large. In other words, the substantial rigidity of the overload prevention unit 43 differs between when the load 20 in the axle direction is small and when it is large. When the load 20 in the axle direction is small, the amount of deformation of the overload prevention unit 43 is large with respect to the amount of change in the load 20 in the same axle direction as compared with the case where the load 20 is large.

  When the load 20 in the axle direction acts, the sensing portion 4a and the overload prevention portion 43 are deformed in the axle direction, and the gap in the axle direction between the hub 3 and the wheel 1 is reduced. When the load 20 in the axle direction is small, the overload prevention unit 43 contacts the hub side and the wheel side to support the load 20 in the axle direction, but the supported load is small. Therefore, the influence on the deformation of the sensing unit 4a is small, and the influence on the measurement accuracy of the tire acting force is small. On the other hand, when the load 20 in the axle direction is large, the overload prevention unit 43 can support a large load, and excessive stress acts on the sensing unit 4a or excessive deformation occurs in the sensing unit 4a. Can be suppressed.

  As shown in FIG. 9, the overload prevention portion 43 of the present embodiment is disposed in different regions in the axle direction and has a first configuration portion (first support member configuration portion) 43 a and a second configuration that are different in rigidity. Part (second support member constituting part) 43b. The first component 43a has a higher rigidity than the second component 43b. In the overload prevention unit 43, the first component 43a is disposed on the wheel side, and the second component 43b is disposed on the vehicle body side. The wheel side end portion of the first component 43a is fixed to the vehicle body side of the wheel side plate 4b. Further, the end of the second component 43 b on the vehicle body side is in contact with the brake rotor 2. The end of the second component 43b on the vehicle body side may be fixed to the brake rotor 2.

  When the load 20 in the axle direction is small, the first component 43a and the second component 43b contract according to their rigidity. When the load 20 in the axle direction is small because the rigidity of the second component 43b is small compared to the rigidity of the first component 43a, the contraction of the second component 43b compared to the first component 43a. The degree of. When the amount of contraction of the second component part 43b becomes a certain amount or more, the second component part 43b does not contract any more or becomes difficult to contract, and the first component part 43a mainly contracts. That is, when the load 20 in the axle direction is large, the rigidity of the first component 43a has a greater influence on the contraction of the overload prevention unit 43 than when the load 20 in the axle direction is small. As a result, when the load 20 in the axle direction is large, the deformation amount of the overload prevention unit 43 is small with respect to the amount of change in the load 20 in the same axle direction as compared with the case where the load 20 is small. In other words, when the load 20 in the axle direction is large, the substantial rigidity of the overload prevention unit 43 is increased as compared with the case where the load 20 is small. Therefore, when the load 20 in the axle direction is large, the overload prevention unit 43 can support a large load, an excessive stress acts on the sensing unit 4a, or an excessive deformation occurs in the sensing unit 4a. Can be suppressed.

  In addition, arrangement | positioning in the axle direction of the 1st structure part 43a and the 2nd structure part 43b is not limited to the arrangement | positioning of this embodiment. For example, the 2nd structure part 43b may be arrange | positioned in the center part of the axle direction in the overload prevention part 43, and may be arrange | positioned at the edge part by the side of a wheel.

1-1 Tire acting force detection device 1 Wheel 2 Brake rotor 3 Hub 4 Sensor plate 4a Sensing unit 4b Wheel side plate 4c Hub side plate 4d Sensor 4g Overload prevention unit 9 Transmission circuit 13 Sensor wiring 17 Brake caliper 18 Reception circuit 19 Vehicle Control computer 20 Load in the axle direction 21 Load in the circumferential direction 30 Rotation side circuit portion 31 Fixed side circuit portion 41, 43 Overload prevention portion 42 Connecting member 43a First component portion 43b Second component portion Fx Front / rear force Fy Lateral force Fz Up / down Force Mx Overturning moment (moment by lateral force)
My rotational torque Mz Self-aligning torque P1 Axle direction stress ratio P2 Bending stress ratio S1 Axle direction rigidity ratio S2 Bending stiffness ratio

Claims (6)

Tire action force detection for detecting a tire action force acting on a tire in a vehicle including a hub rotatably supported around an axle, a wheel connected to the hub, and a tire mounted on the wheel A device,
A connecting portion for connecting the hub and the wheel in the axle direction;
Detecting means for detecting the deformation amount of the connecting portion,
Detecting the tire acting force based on the deformation amount detected by the detecting means;
And a support member disposed in parallel with the connecting portion between the hub and the wheel in the axle direction and fixed to one of the hub side or the wheel side and facing the other in the axle direction. ,
The connecting portion is deformed in the axle direction by a load that brings the hub and the wheel close to each other in the axle direction due to the tire acting force, thereby reducing a gap in the axle direction between the support member and the other,
When the load is small, the support member is separated from the other, and the connection portion supports the load. When the load is large, the support member abuts the other, and the connection The tire acting force detection device, wherein the load is supported by a portion and the support member. Tire action force detection for detecting a tire action force acting on a tire in a vehicle including a hub rotatably supported around an axle, a wheel connected to the hub, and a tire mounted on the wheel A device,
A connecting portion for connecting the hub and the wheel in the axle direction;
Detecting means for detecting the deformation amount of the connecting portion,
Detecting the tire acting force based on the deformation amount detected by the detecting means;
And a support member disposed in parallel with the connecting portion between the hub and the wheel in the axle direction.
The connecting portion is deformed in the axle direction by a load that brings the hub and the wheel close to each other in the axle direction due to the tire acting force, thereby reducing a gap in the axle direction between the hub and the wheel,
The support member is supported at a position separated from the hub side and the wheel side in the axle direction when the load is not applied,
When the load is small, the support member is separated from both the hub side and the wheel side, and the connection portion supports the load, and when the load is large, the hub side and the wheel Each of the wheel side and the support member abut, and the load is supported by the connection portion and the support member. Tire action force detection for detecting a tire action force acting on a tire in a vehicle including a hub rotatably supported around an axle, a wheel connected to the hub, and a tire mounted on the wheel A device,
A connecting portion for connecting the hub and the wheel in the axle direction;
Detecting means for detecting the deformation amount of the connecting portion,
Detecting the tire acting force based on the deformation amount detected by the detecting means;
And a support member disposed in parallel with the connecting portion between the hub and the wheel in the axle direction, and fixed to at least one of the hub side or the wheel side,
The support member is in contact with each of the hub side and the wheel side when a load that causes the hub and the wheel due to at least the tire acting force to approach each other in the axle direction does not act,
The connecting portion and the support member are deformed in the axle direction by the load, thereby reducing a gap in the axle direction between the hub and the wheel,
The ratio of the deformation amount of the support member in the axle direction to the change amount of the load when the load is small is the ratio of the deformation amount of the support member in the axle direction to the change amount of the load when the load is large. Tire action force detection device characterized in that it is larger than the above. In the tire acting force detection device according to claim 3,
The change of the load when the load is small by having the first support member constituent part and the second support member constituent part that are arranged in different regions in the axle direction and have different rigidity from each other. The ratio of the deformation amount in the axle direction of the support member to the amount is larger than the ratio of the deformation amount in the axle direction of the support member to the change amount of the load when the load is large. Tire force detection device. In the tire acting force detection device according to any one of claims 1 to 4,
The ratio of the rigidity of the support member to the rigidity of the connection portion in the deformation in the axle direction is larger than the ratio of the rigidity of the support member to the rigidity of the connection portion in a bending deformation in a direction orthogonal to the axle direction. A tire acting force detection device characterized by the above. In the tire acting force detection device according to any one of claims 1 to 5,
A plurality of first fastening portions arranged at intervals in the circumferential direction, each fastened to the hub;
A plurality of circumferentially spaced intervals, each having a second fastening portion fastened to the wheel,
The connecting portion connects the first fastening portion and the second fastening portion in the axle direction so that the hub and the wheel are connected to the axle via the first fastening portion and the second fastening portion. Connected in the direction,
In the circumferential direction, the first fastening portion and the second fastening portion are alternately arranged. A tire acting force detection device, wherein:

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