JP4367909B2 - Tire contact force detection device and pneumatic tire - Google Patents

Description

  The present invention relates to a tire contact force detection method and apparatus, and a pneumatic tire in which a sensor of the apparatus is embedded, and more particularly, to know a relationship between forces acting when a tread surface of a pneumatic tire is grounded. The present invention relates to a tire contact force detection method and apparatus, and a pneumatic tire.

  In a pneumatic tire, if the relationship of the force acting when the tread surface comes into contact with the ground can be known, it will greatly contribute to the development of the tread pattern. In particular, in the block pattern, the performance of the block greatly depends on the force applied to the block at the time of ground contact. Therefore, if it is known what kind of force is acting on the ground in the same block, it is possible to develop a highly safe block pattern.

Conventionally, techniques for measuring the lateral force and grip level of tires have been proposed (see, for example, Patent Documents 1 and 2), but what kind of force is acting in the same block? No proposal has been made for the technology to solve this problem.
JP 63-242704 A Japanese Patent Laid-Open No. 2002-82004

  An object of the present invention is to provide a tire contact force detection method and device capable of knowing the relationship between forces acting when the tread surface of the tread contacts the ground, and a pneumatic tire to which a sensor of the device is attached.

The tire contact force detection device of the present invention includes a sensor (10) in which an electrode (14) connected in series to a DC power source (9) is attached to a pressure-sensitive conductive rubber body (8), and a current flowing through the sensor (10). A tire mounting unit (1) that includes a plurality of units (13) including a transmission unit (12) that transmits a detection signal that is a change in value, and is embedded in a tread portion (4) of a pneumatic tire (3) ; A vehicle mounting unit (2) including a receiving unit (19) for receiving a detection signal from the transmission unit (12) and a processing unit (20) for processing the detection signal received by the receiving unit (19 ) ; A first sensor in which the electrode (14) is attached to the inner surface (8a) and the outer surface (8b) in the tire radial direction of the pressure-sensitive conductive rubber body (8). (10A) and the electrode (14) The sensor (10) is constituted by the second sensor (10B) attached to both side surfaces (8c) in the tire width direction of the piezoelectric rubber body (8), and the sensor (10) is connected to the tread portion (4). A plurality of sensors are arranged so as to be aligned along the tread surface direction, and the force value Fv calculated based on the value of the detection signal of the first sensor (10A) and the value of the detection signal of the second sensor (10B) are used. The processing unit (20) calculates the ratio Fw / Fv with the force value Fw calculated based on the above .

The pneumatic tire of the present invention includes a sensor (10) in which an electrode (14) connected in series to a DC power source (9) is attached to a pressure-sensitive conductive rubber body (8), and a current value flowing through the sensor (10). A pneumatic tire (3) in which a tire mounting unit (1) including a plurality of units (13) including a transmission unit (12) that transmits a detection signal that is a change is embedded in a tread portion (4) , A first sensor (10A) having the electrode (14) attached to an inner side surface (8a) and an outer side surface (8b) in the tire radial direction of the pressure-sensitive conductive rubber body (8), and the electrode (14) The sensor (10) is constituted by the second sensor (10B) attached to both side surfaces (8c) in the tire width direction of the piezoelectric rubber body (8), and the sensor (10) is connected to the tread portion (4). So that they line up along the tread direction. Characterized in that disposed.

  According to the above-described present invention, the plurality of sensors arranged so as to be aligned along the tread surface direction of the tread portion each have a resistance of the pressure-sensitive conductive rubber body when the tread surface treads on the road surface and deforms. A detection signal whose current value has changed due to a change is sent to the transmission unit, input from the transmission unit to the processing unit via the reception unit, and the value of the force that was applied during deformation based on the value of the detection signal input by the processing unit Therefore, it is possible to know the relationship between the forces acting when the tread surface comes in contact with the ground, which greatly contributes to the development of a tread pattern with improved safety.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an embodiment of a tire contact force detection device according to the present invention. Reference numeral 1 denotes a tire mounting unit that is mounted on a tire, and 2 is a vehicle mounting unit that is mounted on a vehicle.

  As shown in FIG. 2, the tire mounting unit 1 is embedded in a block 7 that is partitioned and formed by a groove 6 provided in the tread portion 5 of the tread portion 4 of the pneumatic tire 3. 4 shows an example embedded in the center portion 4A and the shoulder portion 4B. When the tire mounting unit 1 is embedded, it is preferably exposed so as to be flush with the tread surface 5 as shown in the figure, but may be embedded so as not to be exposed to the tread surface 5.

  The tire mounting unit 1 includes a pressure-sensitive conductive rubber body 8 that is deformed when the tread surface 5 of the tread portion 4 contacts the road surface, and a sensor 10 (see FIG. 3) including a DC power source 9 connected in series therewith, A plurality of units 13 each including a transmission unit 12 that transmits a detection signal of the sensor 10 via the antenna 11 are provided. The transmission unit 12 uses a DC power source 9 as a power source, and transmits at a predetermined time interval. The strength of transmission / reception between the transmitter 12 and the receiver 19 described later can be about 0.1 to 10 mV / m.

  As shown in FIG. 4, each sensor 10 is provided with electrodes 14 on the inner surface 8a and the outer surface 8b in the tire radial direction of the pressure-sensitive conductive rubber body 8, and the pressure-sensitive conductive rubber body 8 is compressed and deformed in the tire radial direction. At this time, the resistance value is changed (decreased), and thereby a detection signal for changing (increasing) the current value is output to the transmission unit 12 to detect a force acting in the vertical direction on the tread surface 5. . Each connection is made with a conductive rubber body 15, and the outside of the sensor 8 and the transmitter 12 is covered with an insulating rubber layer 16. In the figure, reference numeral 17 denotes an insulating rubber layer disposed between the pressure-sensitive conductive rubber body 8 and the conductive rubber body 15.

  As shown in FIG. 5, each unit 13 is arranged in the block 7 so that the sensors 10 are arranged along the tread surface direction (direction in which the tread surface 5 extends) of the tread portion 4.

  The vehicle mounting unit 2 is connected to the receiving unit 19 that receives the detection signal from each transmitting unit 12 via the antenna 18, the processing unit 20 that processes the detection signal from the receiving unit 19, and the processing unit 20. A display unit 21 is provided.

The processing unit 20 calculates the force acting in the vertical direction on the tread surface 5 using the average value from the detection signal value of each sensor 10. That is, when the force F acts on the block 7 at the time of grounding, the resistance value R of the pressure-sensitive conductive rubber body 8 decreases, and the current value I flowing through the circuit increases. Since the force F acting on the block 7 is inversely proportional to the change amount ΔR of the resistance value R of the pressure-sensitive conductive rubber body 8, if the voltage of the DC power supply 9 is E and the change amount ΔI of the current value I is
F = k / ΔR = k · ΔI / E
Is calculated as However, k is a constant and takes the characteristic value of the rubber used for the pressure-sensitive conductive rubber body 8 to be used.

  Each data calculated by the processing unit 20 is displayed on the display unit 21.

  In the tire contact force detection device described above, when the tread portion 5 of the tread portion 4 contacts the road surface and the block 7 is compressed and deformed, the resistance value of the pressure-sensitive conductive rubber body 8 changes, and thereby the current value changes. The detection signal is output from each sensor 10 to the transmission unit 12, the detection signal is transmitted from the transmission unit 12 to the reception unit 19, input from the reception unit 19 to the processing unit 20, and input to the processing unit 20. Based on this value, the force acting in the direction perpendicular to the tread surface 5 during compression deformation is calculated.

  Therefore, it is possible to elucidate the magnitude of the force acting in the vertical direction and the lateral direction on the tread surface 5 in the same block 7, so it is great for designing a block pattern with improved safety. Contribute.

  FIG. 6 shows another example of a sensor used in the tire contact force measuring device of the present invention. In the sensor 10 described above, electrodes 14 are provided on both side surfaces 8c of the pressure-sensitive conductive rubber body 8 in the tire width direction. is there. As a result, when the pressure-sensitive conductive rubber body 8 is compressed and deformed in the tire width direction X, the resistance value is changed (decreased), and thereby a detection signal for changing (increasing) the current value is output to the transmission unit 12. The force acting in the width direction X can be detected. As a result, the lateral force acting in the same block 7 can be elucidated, and the grip force during actual running can be recognized, which greatly contributes to safe running.

  FIG. 7 shows still another example of the sensor used in the tire contact force measuring device of the present invention. In the sensor 10 described above, the electrodes 14 are provided on both side surfaces 8d in the tire circumferential direction of the pressure-sensitive conductive rubber body 8. It is. As a result, when the pressure-sensitive conductive rubber body 8 is stretched and deformed in the tire circumferential direction, the resistance value is changed (increased / decreased), and thereby a detection signal for changing (increasing / decreasing) the current value is output to the transmission unit 12. The force acting in the direction Y can be detected. As a result, it is possible to elucidate what kind of force is acting in the tire circumferential direction Y in the same block 7, and it is safe because the grip force in the tire circumferential direction during actual running can be recognized. Contributes greatly to driving.

  FIG. 8 shows another embodiment of the tire contact force measuring device of the present invention, which is a combination of the sensors 10 described above.

  As shown in FIG. 4, the plurality of units 13 includes a first unit 13A including a first sensor 10A in which electrodes 14 are provided on the inner surface 8a and the outer surface 8b in the tire radial direction of the pressure-sensitive conductive rubber body 8. As shown in FIG. 6, a second unit 13B having a second sensor 10B in which electrodes 14 are provided on both side surfaces 8c of the pressure-sensitive conductive rubber body 8 in the tire width direction, and as shown in FIG. The piezoelectric conductive rubber body 8 is composed of a plurality of sets of units 13 ′ including a third unit 13C including a third sensor 10C provided with electrodes 14 on both side surfaces 8d in the tire circumferential direction.

  The first unit 13A changes the resistance value when the pressure-sensitive conductive rubber body 8 is compressed and deformed in the tire radial direction, and outputs a detection signal that changes the current value from the first sensor 10A to the transmission unit 12, A force acting in a direction perpendicular to the tread surface 5 is detected.

  The second unit 13B changes the resistance value when the pressure-sensitive conductive rubber body 8 is compressed and deformed in the tire width direction, and outputs a detection signal that changes the current value from the second sensor 10B to the transmission unit 12, The force acting in the tire width direction is detected.

  The third unit 13C changes the resistance value when the pressure-sensitive conductive rubber body 8 expands and contracts in the tire circumferential direction, and outputs a detection signal that changes the current value from the third sensor 10C to the transmission unit 12, The force acting in the tire circumferential direction is detected.

  As shown in FIG. 9, each set of units 13 ′ including the first, second, and third units 13 </ b> A, 13 </ b> B, and 13 </ b> C includes sensors 10 </ b> A, 10 </ b> B, and 10 </ b> C along the tread surface direction of the tread portion 4 in the block 7. Are arranged in a line.

  The processing unit 20 of the vehicle mounting unit 2 uses the maximum value from the detection signal values of the sensors 10A, 10B, and 10C, and calculates the force that acts at the time of grounding in the same manner as described above.

  Further, for each unit 13 ′ of each set, the force value Fv calculated based on the detection signal value of the first sensor 10A, and the force value Fw calculated based on the detection signal value of the second sensor 10B The ratio Fw / Fv is calculated to obtain the coefficient of friction in the tire width direction. Further, a ratio Fc / Fv between the value Fv and the force value Fc calculated based on the value of the detection signal of the third sensor 10C is calculated to obtain a friction coefficient in the tire circumferential direction. These friction coefficients serve as an index for evaluating the grip ability of the tire.

  Further, the ratio QB / QA between the integrated value QB of the detection signal of the second sensor 10B and the integrated value QA of the detection signal of the first sensor 10A, and the integrated value QC and the integrated value QA of the detection signal of the third sensor 10C. The ratio QC / QA is calculated and calculated every time it is detected, and whether or not the distribution state is within a predetermined safe range, that is, the grip ability and the margin are determined and evaluated. The value calculated here is the average friction coefficient.

  FIG. 10 shows an example of a signal detected by the first sensor 10A, FIG. 11 shows an example of a signal detected by the second sensor 10B, and FIG. 12 shows a graph of an example of a signal detected by the third sensor 10C. The horizontal axis represents time, the vertical axis represents force, the solid line represents the center portion 4A, and the broken line represents the shoulder portion 4B.

  FIG. 13 shows an example of a graph showing the relationship between the average friction coefficient distribution obtained and a predetermined range N that is considered safe. The horizontal axis represents the average friction coefficient Mx in the tire width direction, and the vertical axis represents the average friction coefficient My in the tire circumferential direction.

  Each data calculated by the processing unit 20 is displayed on the display unit 21.

  In this tire contact force measuring device, in the same block 7, in addition to the force acting in the direction perpendicular to the tread surface 5, the force acting in the tire width direction X, the force acting in the tire circumferential direction Y, the grip ability is Since it becomes possible to evaluate, it contributes more greatly to the design of the block pattern with improved safety. In addition, information for safely traveling in actual vehicle traveling can be obtained.

  As described above, it is preferable that the unit 13 ′ is a set of the first, second, and third units 13A, 13B, and 13C because the grip ability can be evaluated. However, if necessary, any two units may be combined. It may be configured as a set.

  FIG. 14 shows another example of the sensor used in the tire contact force detection device of the present invention, in which the above-described force can be detected until the block 7 reaches the wear limit.

  The sensor 10 has a laminated structure of the layered pressure-sensitive conductive rubber bodies 8 connected in parallel via the insulating rubber layer 25, and when the wear of the block 7 reaches the pressure-sensitive conductive rubber body 8, it sequentially separates from the tread surface 5 side. It is possible.

  The first pressure-sensitive conductive rubber body 8X from the inside is disposed so as to be a position for notifying that the tire usage limit has been reached. The resistance value of the pressure-sensitive conductive rubber body 8 may be the same or different.

  The processing unit 20 described above can further determine the wear state of the tread portion from the magnitude of the detection signal changed by the separation of the pressure-sensitive conductive rubber body 8. The value of the input detection signal is compared with a plurality of preset threshold values (the same number as the number of conductive rubber resistors 8), and the wear state of the block 7 is determined from the result.

  For example, when the pressure-sensitive conductive rubber body 8 closest to the tread surface 5 is detached due to wear (including the case where the pressure-sensitive conductive rubber body 8 disappears due to wear), the resistance value increases and the current value decreases when not grounded. The value is smaller than the maximum threshold value and larger than the next larger threshold value, and a predetermined wear amount (wear state) is obtained accordingly.

  Further, when wear progresses and the pressure-sensitive conductive rubber body 8X is detached, the resistance value becomes maximum and the minimum current value becomes a detection signal when not grounded. The value becomes smaller than a minimum threshold value indicating that the wear has reached the tire use limit, and a predetermined wear amount (wear state) is obtained accordingly. The data obtained based on the threshold value in this way is displayed on the display unit 21 by a numerical display of the wear amount, a wear degree that represents the wear amount in stages, and the like.

  Further, each time the wear state changes, the value of k described above is corrected to calculate the force acting in the vertical direction on the tread surface 5, the force acting in the tire width direction X, and the force acting in the tire circumferential direction Y. Is done. Such a tire contact force detection device may be used.

  In FIG. 14, the electrode 14 is provided on the both sides 8c in the tire width direction of the pressure-sensitive conductive rubber body 8, but the electrode 14 is provided on both sides 8d in the tire circumferential direction of the pressure-sensitive conductive rubber body 8. Alternatively, even if the electrode 14 is provided on the inner surface 8a and the outer surface 8b in the tire radial direction of the pressure-sensitive conductive rubber body 8, the same can be done.

  FIG. 15 shows a tire contact force detection device of FIG. 9 in which the tire mounting unit 1 is composed of a set of units 13 ′, and the set of units 13 ′ is arranged in the block 7 in the same manner as described above. The grip strength can be evaluated. In this manner, the gripping force of the entire block 7 may be evaluated using the main configuration of the present invention. In addition, one set of units 13 ′ is configured by combining any two units of the first, second, and third units 13A, 13B, and 13C as needed, and any of the units 13 ′ that act on the block 7 It is also possible to detect two forces.

  In the present invention, the sensors 10, 10 </ b> A, 10 </ b> B, and 10 </ b> C described above may be connected in series with piezoelectric elements instead of the DC power supply 9. Due to the deformation of the block 7 due to the grounding, the piezoelectric element is subjected to a compressive deformation, thereby generating an electromotive force in the piezoelectric element and performing the same function as the DC power source 9.

  As a piezoelectric material used for the piezoelectric element, for example, a zirconate-based ceramic can be preferably used. When the piezoelectric element is used, a high-frequency signal is periodically transmitted from the vehicle mounting unit 2 side to the tire mounting unit 1 side, and the tire mounting unit 1 side operates the tire mounting unit 1 by changing it to electric power. It is preferable to transmit the detection signal from the receiver to the receiver 19.

  As shown in FIG. 2, the tire mounting unit 1 is preferably disposed in the center portion 4A and the shoulder portion 4B of the tread portion 4 when being mounted on the pneumatic tire 3, whereby the center portion 4A and A comparative study in the shoulder portion 4B becomes possible.

  Further, when the tire mounting unit 1 is arranged in the center portion 4A and the shoulder portion 4B and the sensor 10 shown in FIG. 14 is used, the processing unit 20 described above is embedded in the center portion 4A and the shoulder portion 4B. Each wear amount is obtained based on the detection signal from the sensor 10, and the average wear amount, the remaining average amount until the wear reaches the tire use limit (average life), and the larger of both wear amounts The amount of wear until the wear reaches the tire use limit (minimum wear life), the wear ratio between the center portion 4A and the shoulder portion 4B, and the obtained data are displayed on the display unit 21 It is good to make it.

  The present invention can be suitably used to detect the force acting on the block 7 as described above. However, the tire mounting unit 1 is limited to that, and is embedded in a rib partitioned by a circumferential groove. Further, it is possible to detect what kind of force is acting on the rib at the time of grounding. This contributes to the development of a rib pattern suitable for safe driving.

It is explanatory drawing which shows one Embodiment of the tire ground-contact force detection apparatus of this invention. FIG. 5 is a cross-sectional explanatory view showing a state where the tire mounting unit is attached to the pneumatic tire. It is circuit explanatory drawing of a sensor. It is explanatory drawing of a unit. FIG. 5 is an explanatory diagram showing the arrangement of each unit of a tire mounting unit embedded in a block. It is explanatory drawing of the unit which has another sensor. It is explanatory drawing of the unit which has another sensor. It is explanatory drawing which shows other embodiment of the tire ground-contact force detection apparatus of this invention. FIG. 9 is an explanatory diagram showing an arrangement of units of a tire mounting unit embedded in a block in the apparatus of FIG. 8. It is a graph which shows an example of the signal detected by the 1st sensor. It is a graph which shows an example of the signal detected by the 2nd sensor. It is a graph which shows an example of the signal detected by the 3rd sensor. FIG. 5 is a graph in which the average friction coefficient in the tire width direction is plotted on the horizontal axis and the average friction coefficient in the tire circumferential direction is plotted on the vertical axis. It is explanatory drawing of the unit which has another sensor structure. FIG. 6 is an explanatory view of a main part showing still another embodiment of the tire contact force detection device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire mounting unit 2 Vehicle mounting unit 3 Pneumatic tire 4 Tread part 4A Center part 4B Shoulder part 5 Tread surface 6 Groove 7 Block 8 Pressure-sensitive conductive rubber body 8a Inner side surface 8a Outer side surface 8c, 8D Side surface 9 DC power supply
DESCRIPTION OF SYMBOLS 10 Sensor 10A 1st sensor 10B 2nd sensor 10C 3rd sensor 12 Transmission part 13 Unit 13 'set of unit 14 Electrode
19 receiving unit 20 processing unit

Claims (6)

A sensor (10) in which an electrode (14) connected in series to a DC power source (9) is attached to a pressure-sensitive conductive rubber body (8), and a detection signal that is a change in the current value flowing through the sensor (10) is transmitted. A tire mounting unit (1) including a plurality of units (13) each including a transmission unit (12) and embedded in a tread portion (4) of a pneumatic tire (3) ;
A vehicle mounting unit (2) including a receiving unit (19) for receiving a detection signal from the transmission unit (12) and a processing unit (20) for processing the detection signal received by the receiving unit (19 ) ; A tire contact force detection device comprising :
A first sensor (10A) having the electrode (14) attached to an inner side surface (8a) and an outer side surface (8b) in the tire radial direction of the pressure-sensitive conductive rubber body (8), and the electrode (14) The sensor (10) is constituted by the second sensor (10B) attached to both side surfaces (8c) in the tire width direction of the piezoelectric rubber body (8), and the sensor (10) is connected to the tread portion (4). A plurality of sensors are arranged so as to be aligned along the tread surface direction, and the force value Fv calculated based on the value of the detection signal of the first sensor (10A) and the value of the detection signal of the second sensor (10B) are used. A tire contact force detection device in which the processing unit (20) calculates a ratio Fw / Fv to a force value Fw calculated based on the above . The sensor (10) includes a third sensor (10C) in which the electrode (14) is attached to both side surfaces (8d) in the tire circumferential direction of the pressure-sensitive conductive rubber body (8). The ratio Fc / Fv between the force value Fv calculated based on the value of the detection signal 10A) and the force value Fc calculated based on the value of the detection signal of the third sensor is calculated as the processing unit (20). The tire contact force detection device according to claim 1 , wherein: A plurality of the pressure-sensitive conductive rubber bodies (8) are laminated so as to be in parallel with the tread surface (5) of the tread portion (4), and the pressure-sensitive conductive rubber body has reached the wear of the tread portion (4). The processing unit (20) determines the wear state of the tread portion (4) based on the magnitude of the detection signal changed by the separated pressure-sensitive conductive rubber body (8). The tire ground contact force detection device according to claim 1 or 2 , wherein A sensor (10) in which an electrode (14) connected in series to a DC power source (9) is attached to a pressure-sensitive conductive rubber body (8), and a detection signal that is a change in the current value flowing through the sensor (10) is transmitted. A pneumatic tire (3) in which a tire mounting unit (1) including a plurality of units (13) including a transmission unit (12) is embedded in a tread portion (4) ,
A first sensor (10A) having the electrode (14) attached to an inner side surface (8a) and an outer side surface (8b) in the tire radial direction of the pressure-sensitive conductive rubber body (8), and the electrode (14) The sensor (10) is constituted by the second sensor (10B) attached to both side surfaces (8c) in the tire width direction of the piezoelectric rubber body (8), and the sensor (10) is connected to the tread portion (4). A plurality of pneumatic tires arranged along the tread surface direction . The air according to claim 4 , wherein the sensor (10) has a third sensor (10C) in which the electrode (14) is attached to both side surfaces (8d) in the tire circumferential direction of the pressure-sensitive conductive rubber body (8). Enter tire. A plurality of the pressure-sensitive conductive rubber bodies (8) are laminated so as to be in parallel with the tread surface (5) of the tread portion (4), and the pressure-sensitive conductive rubber body has reached the wear of the tread portion (4). The pneumatic tire according to claim 4 or 5 , wherein the pneumatic tire is configured to sequentially depart from (8) .

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