JP2005170224A - Wheel abnormality detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect mounting failure of a part such as an air adjustment valve mounted to a wheel. <P>SOLUTION: The wheel abnormality detection device 10 comprises a valve constitution body 20 mounted to another part and constituting the wheel; a presumption part 26 for presuming a displacement amount generated on the valve constitution body 20 by action of centrifugal force caused by rotation of the wheel; and a determination part 27 for determining failure of mounting of the valve constitution body 20 based on the displacement amount presumed by the presumption part 26. The wheel abnormality detection device 10 is provided with an acceleration detection device for detecting acceleration of the valve constitution body 20 in rotation of the wheel; and a wheel speed sensor 24 for detecting rotation speed of the wheel. The presumption part 26 presumes the displacement amount from a ratio of the first acceleration of the wheel constitution part detected by the acceleration detection device and the second acceleration of the wheel constitution part calculated from the rotation speed of the wheel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for detecting an attachment failure of a wheel component attached to a wheel.

  In order to drive the vehicle safely, it is necessary to keep the state of the wheels including the tires normal. Therefore, when an abnormality such as insufficient tire air pressure occurs in the wheel, it is necessary to promptly detect this and take appropriate measures.

  Conventionally, it has a tire pressure sensor provided on the wheel and a wireless transmission means for wirelessly transmitting the sensor detection signal, and the abnormality is detected by directly detecting the tire pressure of each wheel by the sensor and wirelessly transmitting it to the vehicle body side. A direct tire pressure detecting device is known. Such a tire pressure sensor is provided integrally with an air adjustment valve, for example. In general, the air regulating valve is fixed to the wheel of the wheel with a nut so that the air regulating valve does not come off due to the centrifugal force generated by the rotation of the wheel.

In Patent Document 1, in the direct tire pressure detection device as described above, a means for detecting the running state of the vehicle provided on the wheel is provided, and the tire pressure signal is transmitted only when the vehicle is in the running state. Thus, a technique for reducing power consumption is disclosed.
JP-A-11-334327 Japanese Patent Laid-Open No. 11-20427

  In Patent Document 1, if the mounting state of the means for detecting the traveling state of the vehicle is poor, the traveling state cannot be detected properly, and a situation may occur in which an air pressure signal is not transmitted to the vehicle body side. In addition, poor mounting of wheel components such as loose valves can cause air leakage. Therefore, it is necessary to keep the mounting state of such wheel components normal for safe driving of the vehicle.

  This invention is made | formed in view of such a condition, The objective is to provide the technique which detects the defect of the attachment state of wheel components, such as an air regulating valve.

  In order to solve the above-described problem, an aspect of the present invention provides a wheel component that is attached to another component and constitutes a wheel together with a displacement amount generated in the wheel component by the action of centrifugal force caused by the rotation of the wheel. Provided is a wheel abnormality detection device that includes an estimation unit that estimates and a determination unit that determines whether or not the wheel component is attached based on the amount of displacement estimated by the estimation unit.

  Here, the “wheel component” is a component that forms a wheel by being combined with other components, and includes, for example, various sensors such as a tire air adjustment valve and a pneumatic sensor.

  According to this aspect, based on the displacement amount of the wheel component estimated by the estimation unit, it can be determined that a mounting defect such as loose nut is generated in the wheel component.

  The wheel abnormality detection device may include an acceleration detection device that detects an acceleration of the wheel component when the wheel rotates, and a wheel speed sensor that detects a rotation speed of the wheel. In this case, the estimation unit calculates the ratio between the first acceleration of the wheel component detected by the acceleration sensor and the second acceleration of the wheel component calculated from the rotation speed of the wheel. Estimate the amount of displacement.

  When the wheel rotates, a force in the wheel outer peripheral direction acts on the wheel component, so that the wheel component deviates from the original installation position if the mounting state is poor. At this time, the output value of the acceleration detecting device shows a value different from the value when it is in the original position. Therefore, the amount of displacement of the wheel component can be calculated by obtaining the ratio between the acceleration calculated from the detection value of the separately provided wheel speed sensor and the acceleration detected by the acceleration detecting means. The acceleration detection means includes an acceleration sensor and a strain sensor.

  According to the wheel abnormality detection device of the present invention, it is possible to detect a mounting failure of a wheel component due to loosening of a nut or the like.

  One embodiment of the present invention is a direct pressure type tire pressure detecting device, which is calculated from an acceleration obtained from an acceleration sensor provided integrally with a tire air regulating valve and an output of a wheel speed sensor provided on a vehicle body. This is a wheel abnormality detection device that detects a defective mounting state of the air adjustment valve due to loosening of a nut or the like by calculating a ratio with the acceleration.

  FIG. 1 is a diagram illustrating an overall configuration of the wheel abnormality detection device 10. FIG. 1 shows cross sections of the tire 50, the wheel rim 52, and the wheel 54. The wheel rim 52 is provided with a valve structure 20 in which an air adjustment valve and a housing are integrally formed. In the housing of the valve component 20, an air pressure sensor that detects the air pressure in the tire, an acceleration sensor 36 that detects the acceleration of the valve component 20, and the air pressure and acceleration data detected by the sensor are transmitted to the vehicle body side. A transmitter for receiving is accommodated (see FIG. 2). Power is supplied from a battery (not shown) to the air pressure sensor, the acceleration sensor, and the transmitter.

  On the vehicle body side, a receiver 22 that receives a signal from the transmitter, a wheel speed sensor 24 for detecting the speed of the wheel, and an estimation unit 26 that estimates the displacement amount of the valve component 20 when the wheel rotates. A determination unit 27 for determining whether the mounting state of the valve structure is good and an alarm device 28 which is a buzzer or a warning lamp for notifying the user of the determination result are provided.

  Note that the estimation unit 26 and the determination unit 27 can be realized by a CPU, a memory, and other LSIs of an arbitrary computer in hardware, and realized by a program in software, but here by their cooperation. It is drawn as a functional block.

  FIG. 2 is a diagram for explaining the detailed structure of the valve structure 20 and the state of attachment to the wheel. As described above, the air pressure sensor 35, the acceleration sensor 36, and the transmitter 37 that wirelessly transmits the air pressure and acceleration detected by these sensors to the vehicle body side receiver 22 are accommodated in the housing 38 of the valve component 20. Has been.

  The valve portion 30 of the valve structure 20 is inserted into a valve mounting hole formed in the wheel rim 52. An elastic rubber grommet 40 is fitted into a portion of the valve portion 30 that passes through the wheel rim 52, thereby making the inside of the tire airtight and damaging the valve structure 20 due to vibration caused by the rotation of the tire. To prevent it. The valve structure 20 is fixed to the wheel rim 52 by a washer 33 and a nut 34 from the outside of the wheel rim 52. In order to make the inside of the tire airtight and to prevent the valve component 20 from coming off, the torque of the nut 34 is preferably managed appropriately.

  The valve portion 30 of the valve structure 20 includes a valve cap 32 that protrudes outside the wheel rim. When the valve cap 32 is removed, the valve opening (not shown) of the valve core appears. The valve port portion of the valve core communicates with the inside of the tire through a not-shown through hole so that air can be supplied.

  The air pressure sensor 35 is, for example, a semiconductor pressure sensor, detects air pressure in the tire, and transmits air pressure data to the vehicle body side via the transmitter 37. The acceleration sensor 36 is, for example, a piezoelectric element type sensor, and is arranged mainly to detect the radial acceleration of the tire.

  Although the air pressure may be detected by the air pressure sensor 35 at all times, the present embodiment is configured to detect the air pressure only when the wheel rotates. This can be realized as follows. That is, when the wheel rotates, the valve component 20 attached to the wheel rim 52 also rotates. The acceleration sensor 36 detects the acceleration generated by the rotation, and the air pressure sensor 35 is operated only when the output of the acceleration sensor 36 exceeds a predetermined value. Thereby, the power consumption of the air pressure sensor 35 and the transmitter 37 can be reduced and the battery life can be extended.

  Next, with reference to FIG. 3, the state of the valve structure 20 during tire rotation will be described. In FIG. 3, the dotted line is the valve structure 20 when the wheel is stationary, and the solid line is the valve structure 20 when the wheel rotates. Among the valve components 20, the housing 38 is heavier than the valve unit 30, and therefore, a force that displaces the housing outward in the tire radial direction by the rotation of the wheel acts. Since an elastic rubber grommet is sandwiched in the wheel rim penetrating portion of the valve component 20, the entire valve component 20 is tilted when the rubber is crushed.

  In addition, if there is an improper installation due to inadequate tightening torque management, loose nuts due to vibration, breakage / deterioration of the grommet, etc., a gap is created between the wheel rim 52 and the valve component 20, so that the valve component 20 The outward displacement of the tire in the radial direction of the tire is greater than that during normal installation. In such a case, the acceleration detected by the acceleration sensor 36 in the housing 38 has a detected value that differs greatly between normal attachment and poor attachment even if the wheel speed is the same.

  More specifically, for example, it is assumed that the radial acceleration detected when the acceleration sensor 36 is in a normal position is G1. When the valve component 20 is tilted due to an improper attachment and becomes a solid line, the acceleration detected by the acceleration sensor 36 becomes G1 cos θ even if the wheel speed is the same. Therefore, as the inclination θ increases, the acceleration detected by the acceleration sensor 36 decreases. Normally, the acceleration threshold value for turning on the air pressure sensor 35 is set in consideration of the amount of deformation of the grommet and the amount of looseness of the nut. However, if the valve component 20 is greatly inclined, the air pressure sensor 35 is There is a possibility that the timing to turn on is not appropriate. Furthermore, when the displacement amount of the valve structure 20 becomes large, there is a possibility that air leakage of the tire may occur or the valve structure itself may be damaged by vibration.

  Therefore, in the present embodiment, a method for detecting a mounting failure of the valve component 20 using a detection value of a wheel speed sensor 24 separately provided on the vehicle body is provided.

  Hereinafter, with reference to the flowchart of FIG. 4, a method for detecting defective attachment of the valve component in the present embodiment will be described. First, the estimation unit 26 acquires the acceleration G1 detected by the acceleration sensor 36 and transmitted via the transmitter 37 via the receiver 22 (S62). Next, the estimation unit 26 calculates the angular velocity ω of the wheel from the detection value of the wheel speed sensor 24 of the same wheel that has acquired the acceleration (S64). The estimation unit 26 calculates the acceleration G2 acting on the valve structure 20 by the following equation using the angular velocity ω (S66).

G2 = r · ω ²
Here, “r” is a radius from the rotation center of the wheel of the acceleration sensor when the attachment is normal.

The determination unit 27 calculates G1 and G2 calculated in S62 and S64, respectively.
G1 <k · G2
Is determined (S68). Here, “k” is a coefficient for determining attachment failure, and is set to k = 0.72, for example. This value corresponds to the displacement angle θ of the valve structure 20 when the attachment is normal and when the attachment is defective.

  If G1 ≧ k · G2 (NO in S68), the determination unit 27 determines that the attachment state of the valve structure 20 is normal, and the flow returns to S62. If G1 <k · G2 (YES in S68), the determination unit 27 determines that the attachment state of the valve component 20 is defective, and issues an alarm to the user via the alarm device 28 (S70). Instead of the alarm, a log may be left in a memory (not shown) so that the user can check later.

  The determination of the defective attachment of the valve structure shown in FIG. 4 is executed for each wheel. Further, this determination may be performed all the time or may be performed at a predetermined interval.

  As described above, it is possible to avoid a situation in which air pressure information cannot be obtained on the vehicle body side by promptly detecting a mounting failure of the valve component 20. Further, as described above, the acceleration threshold value for starting the air pressure sensor 35 is set in consideration of some loosening of the nut, but the nut loosening according to the attachment failure determination method shown in FIG. Therefore, the threshold value can be returned to a value that does not take into account the looseness of the nut.

  When the acceleration obtained from the acceleration sensor 36 is smaller than the acceleration calculated from the output of the wheel speed sensor 24 by a predetermined value or more, the air pressure sensor 35 is forcibly activated from the vehicle body side and air pressure information is transmitted. It becomes possible to make it.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications can be made to combinations of components and processing processes, and such modifications are within the scope of the present invention. Hereinafter, such modifications will be given.

  In another embodiment, the component for which the attachment state is to be determined may be a single air regulating valve or various sensors provided on the wheels.

It is the figure which showed the structure of the wheel abnormality detection apparatus which concerns on one Embodiment of this invention. It is an enlarged view of the valve | bulb structure of FIG. It is a figure which shows the displacement angle of the valve | bulb structural body at the time of attachment normal, and attachment failure. It is a flowchart of the attachment state determination method by one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Wheel abnormality detection apparatus, 20 Valve structure, 22 Receiver, 24 Wheel speed sensor, 26 Estimation part, 27 Determination part, 28 Alarm, 30 Valve part, 32 Valve cap, 33 Washer, 34 Nut, 35 Air pressure sensor, 36 acceleration sensors, 37 transmitters, 38 housings, 40 grommets, 50 tires, 52 wheel rims, 54 wheels.

Claims (4)

Wheel components that are attached to other parts to form a wheel together,
An estimation unit that estimates the amount of displacement generated in the wheel component by the action of centrifugal force caused by the rotation of the wheel;
A determination unit that determines whether or not the wheel component is attached based on the amount of displacement estimated by the estimation unit;
Wheel abnormality detection device composed of An acceleration detection device for detecting the acceleration of the wheel components during wheel rotation;
A wheel speed sensor for detecting the rotation speed of the wheel;
The estimation unit calculates the displacement amount from a ratio between a first acceleration of the wheel component detected by the acceleration detection device and a second acceleration of the wheel component calculated from a rotation speed of the wheel. The wheel abnormality detection device according to claim 1, wherein   The wheel abnormality detection device according to claim 2, wherein the acceleration detection device is an acceleration sensor provided integrally with the wheel component.   The wheel abnormality detection device according to any one of claims 1 to 3, wherein the wheel component is a tire air adjustment valve.

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