JPS6112218B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automobile equipped with an unbalance indicator in the driver's seat that displays the unbalanced state of the wheels.

One of the conditions for ensuring safe driving of a motor vehicle is that the wheels are perfectly balanced. Even small wheel imbalances can be extremely dangerous under high-speed driving conditions. For this purpose, the wheel is removed from the vehicle body and the unbalanced state is measured using a wheel balancer etc.
Testing is being carried out.

By the way, while driving a car, the entire car body may vibrate, but it is difficult to know whether such a state is due to unbalanced wheels or a malfunction of the engine. In such cases, it would be advantageous if the balance state of the wheels could be detected while the vehicle is running.

The present invention aims to provide an automobile that can meet such demands. That is, according to the present invention, a detection means for detecting the unbalance of the wheel is installed in the bearing part of the wheel, and the output signal from this detection means is processed to measure the amount of unbalance and the angular position of the unbalance. The values are configured to be displayed on the respective indicators. This unbalance indicator is installed in the driving operation section, and is designed to detect the unbalanced state of each wheel when the vehicle is running.

Examples of the drawings will be described below.

As shown in FIG. 3, an unbalance amount indicator 3 and an unbalance angle indicator 4 for wheels 2 are attached to a driving operation unit (driver's seat) 20 of an automobile (vehicle body) 1. It is possible to detect whether or not the wheel 2 is unbalanced. In the case of the four-wheeled vehicle shown, wheel 2
There are four operation switches 5, and therefore four operation switches 5 are installed accordingly.

According to the present invention, the unbalanced state of the wheels can be detected from the driver's seat during driving. Furthermore, according to this invention, as will be explained in detail later,
The unbalance of the wheel 2 is detected by a so-called hard type method in which the centrifugal force generated by the unbalance during rotation of the wheel is detected by a piezoelectric element interposed in the wheel bearing. This is done in consideration of the special circumstances in which unbalance detection is performed while the vehicle is running.

In addition, "unbalance" used in this specification
The term "unbalance" means an unbalance amount or an unbalance angle, or both.

The configurations of the detection means for detecting the unbalance of the wheel 2 and the measuring means for measuring the unbalance from the output signal thereof are shown in FIGS. 1 and 2.
One of the features of this configuration is that the output signal from the detection means is integrated twice to output a signal related to displacement, and from this displacement signal, an unbalanced output is obtained using the principle of frequency conversion method (West German Patent No. 1108475). The point is that it is structured. It should be noted that the synchronous rectification operation of the output signal from the detection means is performed using a signal from a proximity switch installed close to the wheel without contacting it.

The means for detecting unbalance of the wheel 2 is a second
As shown in the figure. The wheels are shown in a cross-sectional view, and 6 is an axle provided integrally with the vehicle body 1, and 7 is a bearing. 8 is this bearing part, that is, the wheel 2 and the bearing 7
A piezoelectric element is interposed between the wheels 2 and 2 to accurately detect the centrifugal force generated by the unbalance of the wheel 2 when the wheel 2 is rotated.

Reference numeral 13 denotes a proximity switch, which is composed of a magnet piece _S2 fixed to a flange part 2' integral with the wheel 2, and a transmitting piece S1 fixed to a fixed part ₁ ' connected to the vehicle body 1. It transmits one electric pulse signal for each rotation of the wheel 2 without contacting the wheel 2, that is, a signal synchronized with the rotation of the wheel 2. As will be described later, the fixed position of the magnet piece _S2 of the switch 13 serves as a reference position for detecting an unbalance position (unbalance angle) and has an important meaning. A detection system for extracting these wheel imbalance signals and synchronization signals is provided for each wheel.

The output signal from the unbalance detector, that is, the piezoelectric element 8, is input to a measurement system K that measures and displays the amount of unbalance and the unbalance angle. That is, one measuring system is provided as shown in FIG. 1, and as will be clear from the description below, any of the signals from each of the detection systems described above is input to this measuring system by the operation switch 5. It is becoming more and more common. The signal from the piezoelectric element 8 is therefore first amplified in a preamplifier 9. The output signal from the amplifier 9 indicates the acceleration, and this signal is integrated by the first integrating circuit 10 to become a signal indicating the speed. In other words, if the centrifugal force is F, then F
From the equation =mα, α (acceleration) is obtained when the mass m is constant, and a velocity signal is obtained by integrating this signal. This speed signal is transmitted to the second integrating circuit 11
is integrated again to become a displacement signal. The points of interposing a piezoelectric element in the bearing part and integrating the acceleration signal due to unbalance from this element twice are as follows.
This is a distinctive point in which unbalance measurement technology is applied in consideration of the unique characteristics of automobiles.

The double-integrated output signal is a signal corresponding to the unbalance value, and is a 90° phase-shifted signal from the proximity switch 13 that is input to the synchronous rectifier circuit 12 as the first step to obtain the unbalance value. It is synchronously rectified by two synchronous signals and converted into two DC signals corresponding to unbalanced 90° component force components. This synchronous rectification operation completely eliminates noise signals other than the unbalanced signal. Note that the signal from the proximity switch 13 is amplified by the amplifier circuit 14.

As shown in the figure, the two synchronously rectified DC output signals are input to the frequency conversion circuit 15 for measuring the unbalance value via a storage circuit 19 (to be described later), and the rotational speed of the wheel 2 generated from the oscillator 16 is input to the frequency conversion circuit 15 for measuring the unbalance value. is frequency-converted back to alternating current by a frequency independent of the current (usually greater than the wheel rotation speed). Through the frequency conversion process, the amount of unbalance is measured very stably, and this amount of unbalance is displayed in the form of a numerical value by the amount of unbalance display 3.

As mentioned above, this frequency conversion process is clear in the West German patent, and will be briefly explained as follows. That is, in the above synchronous rectification, the AC signal from the detection means 7 is transmitted to the proximity switch 1.
These two DC signals are converted into DC signals corresponding to unbalanced 90° component force components. That is, it is necessary to find the magnitude and direction of the unbalance from the two outputs from the synchronous rectifier circuit 12 in FIG. This determination is performed using the principle of the frequency conversion method.

Now, in the frequency conversion method, both of the above-mentioned two 90° force component signals are generated at a frequency that is higher (for example, twice) than the synchronization signal frequency and is independent of the rotational speed of the wheel. That is, the two frequency signals of the signal generated from the oscillator 16 are converted into rectangular wave signals. The converted rectangular wave signals are then added together and passed through a filter circuit to create a sine wave signal. When a rectangular wave signal having the same phase as this sine wave signal is generated, its height corresponds to the magnitude of the unbalance and is inputted to the unbalance amount display 3. Further, since the phase difference with the synchronization signal indicates the phase angle from the reference position to the large balance position, that is, the unbalance angle, it is displayed on the display 4 as described later. Through such processing, the magnitude and angular position of the unbalance can be determined with high accuracy.

19 is a synchronous rectifier circuit 12 and a frequency conversion circuit 15
The synchronously rectified signal is stored in a storage circuit interposed between the two. 18 is a phase difference detection circuit that detects the phase difference of the output signal of the frequency conversion circuit 17 and measures the unbalance angle, and the unbalance angle display 4 connected to this circuit displays the value as a numerical value. This indicator 4 is installed in the driving operation section 20 similarly to the unbalance amount indicator 3.

As described above, the angle value displayed by the unbalance angle indicator 4 is based on the position of the proximity switch 13 (magnet piece S ₁ ) which transmits the synchronizing signal.
Therefore, when the driver measures the unbalance status of each wheel 2 by operating the switch 5 while driving, the amount of unbalance and the unbalance angle are displayed on each display 3,
4 and the value remains held on the display, so when repairing, for example, the driver can move the counterweight that matches the unbalance amount to the rim portion 2 of the wheel 2 at the position of the unbalance angle value.
Can be attached to L. When the repair is completed, the unbalanced value is cleared from both displays 3, 4 by a reset operation.

By the way, the operation switch shown in Fig. 3 is
As shown in the figure, each switch is interposed between each detection system and one measurement system K, and each switch is interposed between a piezoelectric element 8 and a preamplifier 9, a proximity switch 13, and an amplifier 14 in FIGS. They are interlocked between each other.

As described above, the present invention can, first of all, accurately measure the presence or absence of unbalanced wheels while driving a car, prevent dangers due to unbalanced wheels, and improve safe driving operation of the car. guarantee. Even if the wheel is to be inspected and repaired at a repair site, there is no need to carry out the work unnecessarily. In addition, since wheel unbalance is detected by detecting centrifugal force using a piezoelectric element interposed in the bearing of the wheel, it has the advantage that the detection means is simple and wheel unbalance can be detected with high accuracy. . Furthermore, measurement using the frequency conversion method guarantees extremely stable and highly accurate measurements even under complex conditions such as when driving a car. Performing synchronous rectification using a signal from a nearby switch simplifies the operation and processing and provides high accuracy. Moreover, only one measurement system is provided to perform such measurements, making it possible to measure each wheel economically.At the same time, since there is only one system, there is less noise, which improves accuracy. Beneficial. Furthermore, repair work for unbalanced parts becomes easier, which greatly contributes to the operability and safety of automobiles.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 2 is a diagram showing the positional relationship between a wheel and a detection means, and FIG. 3 is a schematic diagram of the front half of an automobile body according to an embodiment of the present invention. FIG. DESCRIPTION OF SYMBOLS 1...Automobile, 2...Wheel, 3...Unbalance amount indicator, 4...Unbalance angle indicator, 5...Operation switch, 6...Wheel, 7...Bearing, 8...Piezoelectric element, 1
0, 11...Integrator circuit, 12...Synchronous rectifier circuit, 13
...Proximity switch, 15...Frequency conversion circuit, 16...
Transmitter, 18...phase difference detection circuit.

Claims (1)

[Claims] 1 Detection means for detecting centrifugal force caused by unbalance during rotation of the wheel using a piezoelectric element interposed in the bearing part of the wheel, and a signal that detects the rotation of the wheel without contact and synchronizes with the rotation of the wheel. A detection system consisting of a synchronization signal generation means for generating a signal is provided for each wheel, an integrating circuit that integrates the output signal from the detection means twice, and a signal integrated twice from the synchronization signal generation means. 90 in synchronization with the rotation of the wheel by the signal of
A synchronous rectifier circuit converts each of the force components into DC signals, and each output from this synchronous rectifier circuit
a frequency conversion circuit that converts the output signal of the 90° component force component into AC at a frequency unrelated to the rotational speed of the wheel, adds the converted AC signals and outputs a sine wave signal, and outputs the amount of unbalance. an unbalance amount indicator that displays the amount of unbalance in response to the magnitude of the sine wave signal at the frequency conversion circuit; One unbalance measurement system consisting of a phase difference detection circuit and an unbalance angle display that receives the output from this phase difference detection circuit and displays the unbalance angle of the wheel, and this unbalance measurement system is connected to each detection An operating switch for selectively connecting to one of the systems, and an unbalance amount indicator, an unbalance angle indicator, and each operating switch are installed in a driving operation section of an automobile. A car equipped with an unbalance indicator.