JPH05345569A - Steering wheel - Google Patents

Abstract

PURPOSE:To detect the data of the steering carried out by a driver prior to the rotation of a steering wheel. CONSTITUTION:In a steering wheel, the electrode of an inner flexible base 10 and the electrode of an outer flexible base 20, which are buried in a ring 2 and detect the pressure of the palm to grip the ring 2, are scanned in order. And in such a steering wheel to detect the pressing force between the both electrodes as a variation of the impedance of a sheet form pressure sensitive conductive rubber 30, the detected pressure force is used as a rotation starting prediction signal of the steering wheel, and also as a signal of the control system which must be controlled by the rotation of the steering wheel, so as to improve the responsiveness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering wheel having a pressure sensor arranged in a ring portion of a steering wheel, and more particularly to a steering wheel for detecting an external force applied to the ring portion and its position.

[0002]

2. Description of the Related Art Some conventional steering wheels of this type have an air layer formed over substantially the entire ring portion to detect an external force applied to the ring portion. In addition, the electrodes are arranged on almost the entire ring portion of the steering wheel,
Some have detected that a hand is placed on the ring portion of the steering wheel by short-circuiting the electrodes by hand.

These steering wheels are mainly
It is used as a detector for a drowsiness prevention device and generates an alarm output depending on the difference from normal normal operation. Specifically, for example, the technology disclosed in Japanese Utility Model Laid-Open No. 53-84841 is mounted on a steering wheel of a vehicle which is constantly operated by a driver's hand while the vehicle is traveling, and the technique of touching the driver's hand is two. An electrode and a circuit for detecting a differential value of a current flowing between the electrodes via a driver's hand,
The drowsiness warning device is provided with a circuit that outputs a signal by detecting that the differential value detected by the detection circuit is below a predetermined level for a certain period of time, and an alarm device that operates by the output signal of the circuit. Is used as.

[0004]

As described above, the conventional drowsiness driving warning device detects the external force applied to the ring portion by the air layer of the ring portion and is mounted on the steering wheel of the vehicle. Dozing is determined by the change in resistance between the two electrodes. However, the judgment of the external force applied to the ring portion or the judgment of the resistance value between the two electrodes changes depending on the grip pressure, the electric conductivity of the skin surface, the resistance value peculiar to each person, etc. Therefore, it is not always satisfactory to detect the driving condition of the driver.

On the other hand, in the technical field of electronic control of a vehicle, in the control of power steering, active electronic control suspension, etc., due to the limit of the response speed of the actuator, for example, in power steering, a clutch is applied to a system for applying assist torque. However, even if a relay for opening and closing the motor drive power source is provided, the clutch is engaged at the same time as the ignition switch is turned on, and the motor drive power source is turned on. The clutch configured to improve reliability and open / close control of the power source for driving the electric motor have not been sufficiently utilized in failsafe.

For example, a known electronic control circuit for driving and controlling an electric power steering apparatus is as shown in FIG.

FIG. 10 is a circuit diagram of an electronic control circuit for controlling a conventional electric power steering system.

The microcomputer CPU is composed of a one-chip microcomputer.
It contains OM, RAM, timer, counter, etc. The power is supplied from a constant voltage circuit (not shown). To the input of the microcomputer CPU, the pulse number output of the vehicle speed sensor SS including a permanent magnet that rotates according to the vehicle speed, a reed switch, a resistor, and the like is input after waveform shaping. Further, the output of the torque sensor TS including a strain detecting element is input to the microcomputer CPU via an amplifier and a control compensating circuit for compensating the proportional / integral / differential control constants.

On the other hand, the output of the microcomputer CPU is connected to the relay RY via the relay drive circuit DR3. Therefore, the microcomputer CP
When the relay output of U is "1", the relay RY is excited and its contact ry is closed. When it is "0", the relay RY can be de-energized to open its contact ry. Therefore, if the relay RY is de-energized, the contact ry can be opened and the rotation of the electric motor M can be stopped regardless of the later-described left signal, right signal, and PWM signal (ratio of the output of the duty ratio signal). Yes, it can have fail-safe support.

Further, the output of the microcomputer CPU is connected to the coil of the clutch mechanism CL via the clutch drive circuit DR5, and when the relay output of the microcomputer CPU is "1", the clutch mechanism CL.
Is in a coupled state, and when it is "0", it is in a released state.

The transistor Q1 and the base resistor R1 form a switching circuit, and the microcomputer CPU
The left signal "1" turns on the transistor Q1 via the drive circuit DR1, and the left signal "0" turns off the transistor Q1. Similarly, the transistor Q2 and the base resistor R2 form a switching circuit,
The right signal "1" of the microcomputer CPU turns on the transistor Q2 via the drive circuit DR1.
Further, the transistor Q2 is turned off by the right signal "0".

The transistor Q3 and the base resistor R3 form a switching circuit. When the PWM signal of the microcomputer CPU is "1", the transistor Q3 is turned on via the drive circuit DR2, and when the PWM signal is "0". The transistor Q3 turns off. Similarly, the transistor Q4 and the base resistor R4 form a switching circuit, and the PWM of the microcomputer CPU is
The signal "1" turns on the transistor Q4 via the drive circuit DR2, and the PWM signal "0" turns off the transistor Q4. Therefore, the electric motor M
When the transistor Q1 is turned on by a left signal "1" or the transistor Q2 is turned on by a right signal "1", the transistor Q1 rotates left or right according to the PWM signal of the microcomputer CPU. The diodes D1 to D4 are for flywheels for preventing the transistors Q1 to Q4 from being destroyed.

The conventional electric power steering microcomputer CPU thus configured is program-controlled as follows.

FIG. 11 is a flow chart of a main program for controlling a conventional electric power steering system.

First, the program is started by turning on the ignition switch IG, and in step S1, the RAM and timer built in the microcomputer CPU are cleared and each output port is initialized. That is, the memory for storing the vehicle speed is cleared, the input of the clutch drive circuit DR5 is set to "0" to release the clutch mechanism CL, the input of the relay drive circuit DR3 is set to "0", and the relay RY is turned off, the drive circuit DR1 and the drive circuit DR2. Is set to "0". The clutch mechanism CL is engaged in step S2, the relay RY is excited via the relay drive circuit DR3 in step S3, and the contact ry is closed. In step S4, vehicle speed data is input from the vehicle speed sensor SS, the current vehicle speed is calculated, and the vehicle speed is stored in the memory. Step S
At 5, the output of the torque sensor TS is input, and the output of the torque sensor TS at that time is stored in the memory together with the information on the rotation direction. From the output of the torque sensor TS stored in the memory in step S6, the duty ratio output which is the PWM signal supplied to the electric motor M is calculated, and the output value is determined.

Then, in step S7, a duty ratio signal which is a PWM signal supplied to the electric motor M is output. The PWM signal determined in step S7, that is, the duty ratio and the leftward or rightward rotation direction is output, and thereafter, the routine processing of steps S4 to S7 is continued. In addition, the rotation direction of the electric motor M is output using the polarity of the output of the torque sensor TS stored in the memory. As a result, the assist torque required for steering is supplied according to the steering torque applied by the driver to the steering wheel.

In the power steering constructed as described above, the relay RY is de-excited to open the contact ry, and the rotation of the electric motor M can be stopped regardless of the left signal, the right signal and the PWM signal. The clutch mechanism CL is released by setting the input of the clutch drive circuit DR5 of the microcomputer CPU to "0", but the power steering of this type is temporarily operated by the ignition switch IG. When the program is started by turning on, the relay RY is in an excited state so that the rotation of the electric motor M is always enabled regardless of the left signal, the right signal and the PWM signal. Similarly, the clutch mechanism CL is in the engaged state,
Unless the microcomputer CPU positively detects an abnormal state, the power of the electric motor M cannot be cut off or the clutch mechanism CL cannot be released even when the steering wheel is not rotated.

Therefore, an object of the present invention is to provide a steering wheel that can detect steering information performed by a driver.

[0019]

A steering wheel according to the present invention includes a pressure sensor embedded in a ring portion for detecting a pressure of a palm gripping the ring portion and one electrode extending in a specific direction with respect to a substrate. , The other electrode formed on a substrate facing the surface of the electrode and extending in a direction intersecting with the electrode, and a pressure-sensitive conductor interposed between the surfaces of the electrode.

[0020]

According to the present invention, the external force applied partially or entirely on the electrode surface can be detected by monitoring the change in impedance between one electrode and the other electrode. The movement of the external force applied to the electrode surface can also be detected, the pressure change of the palm holding the ring portion can be analyzed, and the rotation initial signal of the steering wheel can be obtained.

[0021]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 is a plan view of an essential part of a ring portion of a steering wheel according to an embodiment of the present invention. FIG. 2 is a sectional view of the ring portion of the steering wheel according to the embodiment of the present invention.

In the figure, the steering wheel body 1
As is well known, has a pad portion 4 that covers the ring portion 2, the spoke portion 3, and the boss portion based on the core metal 5.
The steering wheel body 1 used in this embodiment
Are not necessarily limited to those having the cored bar 5, and the product has the cored bar 5, but the steering wheel body 1 without the cored bar 5 can also be used in this case. The synthetic resin layer 6 is formed of vinyl chloride or is formed of a material known as the steering wheel body 1 such as integral skin urethane foam.

An inner flexible substrate 10 and an outer flexible substrate 20 are laminated and adhered to the outer periphery of the synthetic resin layer 6 with a pressure-sensitive conductive rubber 30 as a pressure-sensitive conductor of this embodiment interposed therebetween. , Outer flexible substrate 2
A skin layer 7 made of synthetic leather is formed on the outer periphery of 0. The skin layer 7 is subjected to color and surface treatment according to the user's preference. An adhesive is used for joining the skin layers 7, and they are firmly integrated.

FIG. 3 is a development view of the electrode side of the inner flexible substrate 10 used in the steering wheel of one embodiment of the present invention, and FIG. 4 is a development view of the back side of the inner flexible substrate 10 of FIG. 3 on the lead wire side. .. 5 is an electrode side development view of the outer flexible substrate 20 used in the steering wheel of one embodiment of the present invention, and FIG. 6 is a development view of the lead wire side of the back surface of the outer flexible substrate 20 of FIG.

In the inner flexible substrate 10, electrodes 11 are formed in eight groups by conducting wires made of eight gold vapor deposition films substantially at right angles to the length direction of the outer circumference of the ring portion 2. They are independent of each other and there is no conduction relationship between the 8 × 8 electrodes. Similarly, on the opposite surface (back surface) of the inner flexible substrate 10, 64 lead wires 12 connected to 8 × 8 electrodes 11 are formed. 8x
The eight electrodes 11 and the lead wires 12 are electrically connected to each other through through holes (not shown) of the inner flexible substrate 10. The lead wire 12 side of the inner flexible substrate 10 is bonded to the outer periphery of the synthetic resin layer 6, and the lead wire lead-out portion 15 is guided to the pad portion 4 via the spoke portion 3. The inner flexible substrate 10 has electrodes 11 formed in eight groups, and the eight groups are separated by the cutout portions 14. The notch 14 is the inner flexible substrate 1
When 0 is wound around the outer periphery of the ring portion 2, the excess portion is eliminated, and the outer periphery of the ring portion 2 is easily wound. In addition, the portion of the inner flexible substrate 10 formed of a vapor deposition film where the electrode 11 is not formed is the ring portion 2
It is the overlapping margin portion 13 which is the overlapping margin when wound around the outer periphery of the. The lead wire lead portion 15 extends in a direction substantially perpendicular to the length direction of the inner flexible substrate 10 so that the lead wire lead portion 15 can be easily introduced into the spoke portion 3.

The electrode 11 of the inner flexible substrate 10
A known sheet-shaped pressure-sensitive conductive rubber 30 as a pressure-sensitive conductor is arranged on the outer periphery of the side. The pressure sensitive conductive rubber 3
An outer flexible substrate 20 is arranged on the outer periphery of 0.

In the outer flexible substrate 20, the electrode 21 in the lengthwise direction of the outer periphery of the ring portion 2, that is, in the direction substantially perpendicular to the extending direction of the electrode 11 of the inner flexible substrate 10, is vapor-deposited with gold. 64 conductors made of a film are formed. The 64 electrodes 21 are independent of each other, and there is no electrical connection between the 64 electrodes. In addition, on the opposite surface (back surface) of the outer flexible substrate 20,
Similarly, 64 lead wires 22 connected to the 64 electrodes 21 are formed. The electrode 21 and the lead wire 22
Are electrically connected to each other through a through hole (not shown) of the outer flexible substrate 20. The electrode 21 of the outer flexible substrate 20 is electrically connected by a jumper wiring 24 through a through hole (not shown) of the outer flexible substrate 20 so as not to be non-conductive by the cutout portion 26. When the outer flexible substrate 20 is wound around the outer periphery of the pressure-sensitive conductive rubber 30 which is the upper layer of the inner flexible substrate 10, the notch 26 facilitates winding so as to eliminate the excess portion. In addition, the conductive wire made of the vapor deposition film of the outer flexible substrate 20 is used for the electrode 2
The portion where 1 is not formed is the overlapping margin portion 23 which is the overlapping margin when wound around the outer periphery of the ring portion 2.
The lead wire lead portion 25 extends in a direction substantially perpendicular to the length direction of the outer flexible substrate 20 so that it can be easily introduced into the spoke portion 3 together with the inner flexible substrate 10.

Lead wire 22 of outer flexible substrate 20
The side is bonded to the skin layer 7, and the lead wire lead-out portion 25 is guided to the pad portion 4 via the spoke portion 3. The number of electrodes 11 and 21 of this example is 64, and 2 ¹²
Scanning is required, and the time required for scanning cannot be ignored. Therefore, in order to monitor the grip state at high speed, the number of electrodes 11 and 21 may be reduced. The same applies when it is not necessary to make a detailed determination of the distribution of pressing force. However, in order to judge the decrease in the impedance between the electrodes 11 and 21 as a whole, it is necessary to make the distribution density of the electrodes 11 and 21 as high as possible.

The 64 electrodes 11 of the inner flexible substrate 10 and the 64 electrodes 2 of the outer flexible substrate 20
The sheet-shaped pressure-sensitive conductive rubbers 1 extend so as to intersect each other at a substantially right angle. Therefore, in the pressure sensor of this embodiment, when the ring portion 2 of the steering wheel is gripped by the hand, the inner flexible substrate 10
The impedance at the intersection of the electrode 11 of the outer flexible substrate 20 and the electrode 11 of the outer flexible substrate 20 decreases, and the electrode 11 of the inner flexible substrate 10 and the electrode 2 of the outer flexible substrate 20 decrease.
The impedance at the intersection of 1 is reduced by scanning the lead wire 12 and the lead wire 22 connected to them.
The intersection position of can be determined.

The pressure sensor of this embodiment shown in FIG. 1 is provided with two pieces on one side of the ring portion 2 of the steering wheel body 1. Usually, the outer flexible substrate 2 with the pressure-sensitive conductive rubber 30 as the pressure sensor of this embodiment interposed.
0 and the inner flexible printed circuit board 10 are centered on the pad portion 4 of the steering wheel body 1 as required, and the ring portion 2
Multiple sheets are arranged on the left and right sides and the same side. However, in this embodiment, for simplification of description, the pair of pressure-sensitive conductive rubbers 3
The outer flexible substrate 20 and the inner flexible substrate 10 with 0 interposed will be described.

The lead wire 12 connected to the electrode 11 of the inner flexible board 10 is spoken by the lead wire lead-out portion 15, and the lead wire 22 connected to the electrode 21 of the outer flexible board 20 is led up by the lead wire lead-out portion 25. It is guided to the pad section 4 via the section 3.

The pad section 4 receives an output signal of the built-in microcomputer CPU and uses the output as a scan signal to form an electrode selection circuit SC including a counter and a logic circuit.
It is connected to the. The electrode selection circuit SC sequentially scans the electrode 11 of the inner flexible substrate 10 and the electrode 21 of the outer flexible substrate 20, and energizes to measure the impedance between the electrodes 11 and 21. The energization result between the two electrodes 11 and 21 is converted by the A / D conversion circuit AD from an analog signal into a digital signal, and the microcomputer CP
You are typing in U.

This specific circuit configuration is based on the electrode selection circuit S
In C, the electrodes 11 of the inner flexible substrate 10 are sequentially scanned. When the electrode 11 of the inner flexible substrate 10 is selected, the electrodes 21 of the outer flexible substrate 20 are sequentially scanned with reference to it. This scan is performed by opening and closing an analog gate connected to the constant voltage circuit. The current flowing between the electrodes 11 and 21 is detected as a voltage drop corresponding to the impedance change between them. This voltage drop is due to A / D conversion circuit A
An analog signal is converted into a digital signal by D and input to the microcomputer CPU, and both electrodes 11, 21
The digital output is detected in synchronization with the timing applied during the period.

In general, the electrode 1 disposed on the ring portion 2
The impedance change between 1 and 21 is as follows.

FIG. 7 is an output characteristic diagram in the right lane change test at a vehicle speed of 60 km / h in this embodiment.

That is, in general, the inner flexible substrate 10
The output between the electrode 11 and the electrode 21 of the outer flexible substrate 20 is generated by the force that the finger grips the palm with the palm as a reference, but basically, the driver individually Although there was a difference, it is about 1 second ahead of the actual steering angle waveform, which is about a quarter of the steering wheel switching cycle.
Therefore, the rise of the signal which is advanced by about 1 second from the waveform of the actual steering angle can be used as the rotation start prediction signal of the steering wheel.

This type of steering wheel can be used as a power steering as follows.

FIG. 8 is a circuit diagram of electronic control means for driving and controlling an electric power steering apparatus using a steering wheel according to an embodiment of the present invention. In the figure, the same reference numerals and symbols as those of the conventional example indicate the same or corresponding components as those of the present embodiment.
A duplicate description will be omitted.

The difference between this embodiment and the conventional example is that the electrode selection circuit SC receives the output signal of the microcomputer CPU and sequentially scans the electrode 11 of the inner flexible substrate 10 and the electrode 21 of the outer flexible substrate 20, The circuit configuration is such that the result of energization between the electrodes 11 and 21 is converted into an analog signal as a digital signal by the A / D conversion circuit AD and is input to the microcomputer CPU.

The power steering is controlled by the microcomputer CPU as follows.

FIG. 9 is a flow chart of a control program executed by the microcomputer CPU of the power steering of this embodiment.

In the figure, initialization is performed in step S11, vehicle speed input processing is performed by the output of the vehicle speed sensor SS in step S12, and it is determined in step S13 whether there is a torque output of the torque sensor TS.

When there is a torque output from the torque sensor TS in step S13, the routine directly starts from step S18, but when there is no torque output from the torque sensor TS, an inner flexible substrate forming a pressure sensor in step S14. It is judged whether there is a rotation start prediction signal from between the electrode 11 of 10 and the electrode 21 of the outer flexible substrate 20, and when there is no rotation start prediction signal, step S15
Then, the PWM signal is set to "0", the transistors Q3 and Q4 are turned off, the right or left rotation direction signal is set to "0" or "1", and either the transistor Q1 or the transistor Q2 is turned on. Then, in step S16, the input of the clutch drive circuit DR5 is set to "0" to release the clutch mechanism CL, and in step S17.
Then, the input of the relay drive circuit DR3 is set to "0", the relay RY is turned off, and the steps S12 to S1 are performed.
The routine of 7 is repeatedly executed.

When the torque output of the torque sensor TS is not generated in step S13, but the rotation start prediction signal is output from the pressure sensor in step S14, step S1
In step 8, the input of the clutch drive circuit DR5 is set to "1" to connect the clutch mechanism CL, in step S19 the input of the relay drive circuit DR3 is set to "1" to turn on the relay RY, and in step S20, the output of the torque sensor is applied. When the torque output is judged and there is no torque output, steps S12 to S14, step S1
The routine from step 8 to step S20 is repeatedly executed.

Then, in step S20, the torque sensor T
When it is confirmed that the output of S is generated, in step S21, the duty ratio output which is the PWM signal supplied to the electric motor M is calculated according to the vehicle speed and the magnitude and direction of the steering torque of the torque sensor TS, and the output value is determined. To do. Step S
Based on the calculation of the assist torque at 22, the assist torque is output by setting the PWM signal and the right or left rotation direction signal to "0" or "1". The same operation is performed when the output of the torque sensor TS is confirmed in step S13.

As described above, the steering wheel according to the embodiment of the present invention is embedded in the ring portion 2, and the ring portion 2
In a steering wheel that detects the pressure of the palm that grips, a circuit pattern formed of one electrode 11 formed as a conductive parallel line extending in a specific direction of the flexible substrate 10 and a circuit pattern facing the surface of the circuit pattern. A pressure-sensitive element interposed between the surfaces of the circuit pattern formed of the other electrode 21 formed on the flexible substrate 20 as a conductive parallel line extending in a direction intersecting at a substantially right angle with the electrodes 11 and 21 formed of the circuit pattern. An electrode 11 of the inner flexible substrate 10 that includes a pressure-sensitive conductive rubber 30 as a conductor and detects the pressure of the palm holding the ring portion 2.
In the steering wheel that sequentially scans the electrode 21 of the outer flexible substrate 20 and detects the pressing force between the electrodes 11 and 21 as a change in the impedance of the sheet-shaped pressure-sensitive conductive rubber 30, the detected pressing force of the steering wheel is This is used as a rotation start prediction signal.

Therefore, as in the power steering of the above-described embodiment, since it can be detected immediately before the driver turns the steering wheel, it is possible to secure the time to enter the preparatory operation for outputting the assist torque before outputting the assist torque. The time required for opening and closing the circuit and the engagement / disengagement of the clutch mechanism, which are set for fail-safe, can be sufficiently taken, and the reliability of the power steering can be improved. Also, when the power steering is not functioning and is unnecessary, the function as the power steering device can be released and can be used as a manual steering mechanism, so by the way, an abnormality not detected by the abnormality detection circuit occurs. However, those effects can be released when the function as the power steering is not used.

That is, according to the present embodiment, the coupling relationship with the steering wheel is generated electrically and mechanically only while functioning as the power steering.
As long as the steering wheel is not rotated, it functions as manual steering, and the control system and mechanism system that function as power steering can be released, so that the device can be made fail-safe. In addition, it is possible to secure a time for starting the preparatory operation for outputting the assist torque before outputting the assist torque, and improve the responsiveness.

The rotation start prediction signal is embedded in the ring portion 2 and sequentially scans the electrode 11 of the inner flexible substrate 10 and the electrode 21 of the outer flexible substrate 20 for detecting the pressure of the palm holding the ring portion 2. And both electrodes 1
The pressing force between Nos. 1 and 21 is used by adding the total sum of all areas and using the total output. However, according to the experiments by the inventors, the electrodes 11 of the inner flexible substrate 10 and the electrodes 2 of the outer flexible substrate 20 formed in a matrix form.
From 1, it can be determined that the rotation start prediction signal of the steering wheel is obtained by the increase of the pressing force within the specific area.
Further, the turning start prediction signal of the steering wheel can be obtained by the pressing force of a specific part of the palm. In this case, it is necessary to determine the area to which the pressing force is applied, and it takes time to determine the area. Therefore, the magnitude of the pressing force is located above or below the ring portion 2 of the steering wheel. It is preferable to make such a judgment. Then, the rotation start prediction signal of the steering wheel can be used by the area change of the pressing force by the palm.

Further, the electrodes 11 on the left and right inner flexible substrates 10 and the electrodes 21 on the outer flexible substrate 20 on the left and right of the ring portion 2 are sequentially scanned to find a partial difference or a total difference in pressing force between the electrodes 11 and 21. It can also be used as a rotation direction prediction signal. In this way, if the difference in pressing force is used as the rotation direction prediction signal, the preparation operation for rotation, in the power steering described above, the right or left rotation direction signal is set to "0" or "1", and the transistor Q1 or Either one of the transistors Q2 can be turned on. In this case, rather than using the rotation start prediction signal, P
Since the assist torque can be adjusted only by the pulse width of the WM signal, the responsiveness can also be particularly improved.

As a matter of course, as the rotation start prediction signal and / or the rotation direction prediction signal, only one signal can be used, but both signals can also be used.

The turning start prediction signal and / or the turning direction prediction signal in the above embodiment has been described in the case of being used in the power steering device. As with the device, it can also be a control signal for an active electronically controlled suspension that is affected by the rotation of the steering wheel. It can also be used as a four-wheel steering control signal or a four-wheel drive control signal. In either case, it is possible to control the vehicle height, the turning angle of the wheels, the number of revolutions of each wheel, etc., which are caused by the change in the steering angle of the steering wheel.

By the way, the steering wheel of the above-described embodiment is provided with the inner flexible substrates 10 on the left and right of the ring portion 2.
And the electrode 21 of the outer flexible substrate 20,
Although the sheet-shaped pressure-sensitive conductive rubber 30 is disposed so as to intervene, in the case of carrying out the present invention, the driver is
Normally, a pressure sensor composed of one or more inner flexible boards 10 and outer flexible boards 20 and pressure-sensitive conductive rubber 30 may be arranged at a position where the driver holds the palm, and in particular, at a position where the driver stochastically holds the position. Moreover, it may be any position as long as the pressing force of the driver can be strongly detected.
In the case of four spokes as in the present embodiment, a pair of the inner flexible substrate 10 and the outer flexible substrate 20 formed in the same expanded shape can be arranged at two places on the left and right, for a total of four places. Even in the case of two spokes, the pair of the inner flexible substrate 10 and the outer flexible substrate 20 formed in the same expanded shape are reversed upside down and arranged at two places on the left and right, and a total of 4
It can be installed at any place.

Further, the electrode 1 of the inner flexible substrate 10
When the scanning of the electrode 21 of the outer flexible substrate 20 and 1 is performed at a high speed, the wavefront waveform is disturbed by the height of the frequency, and it becomes difficult to detect the impedance decrease of the pressure-sensitive conductive rubber 30, so the pulse width is widened and steady. It is necessary to detect in the state. The wiring densities of the conductive parallel lines of the electrodes 11 of the inner flexible substrate 10 and the electrodes 21 of the outer flexible substrate 20 need to be formed by the pressure-sensitive conductive rubber 30 at intervals such that they do not interfere with each other.

The parallel lines facing the surface of one circuit pattern and extending in the direction intersecting the circuit pattern at a right angle are ideally arranged at a right angle, but in the case of carrying out the present invention. Is the relation with the wiring density of parallel lines,
If the wiring density of parallel lines is rough, set the intersection angle to 90.
It can also be staggered.

Further, one circuit pattern formed as a conductive parallel line extending in a specific direction with respect to the flexible substrate and the surface of the circuit pattern are opposed to each other and intersect the flexible substrate at a substantially right angle to the circuit pattern. The other circuit pattern, which is formed as a conductive parallel line extending in the same direction, may be formed on the two inner flexible boards 10 and the outer flexible board 20 as in the above embodiment, or one flexible board may be formed. It may be formed by bending. Further, the conductive parallel lines extending in a specific direction with respect to the flexible substrate are not limited to parallel straight lines when the present invention is implemented, and a linear circuit pattern may be formed by a curved line or the like. However, when the circuit pattern is formed by conductive parallel lines, the conditions of the inductive capacitance and the electrostatic capacitance can be made uniform, and the position corresponding to the circuit pattern can be easily identified.

[0058]

As described above, according to the steering wheel of the present invention, a plurality of pressure sensors embedded in the ring portion of the steering wheel are provided with one linear electrode extending in a specific direction with respect to the substrate, and the electrode. The other linear electrode that faces the surface of the flexible substrate and extends in a direction intersecting with the electrode with respect to the flexible substrate, and a pressure-sensitive conductor interposed between the surfaces of the electrode.

Therefore, the driver operates the steering wheel by the pressing force detected by the one electrode for detecting the pressure of the palm holding the ring portion and the other electrode, and the pressure-sensitive conductor interposed between the surfaces of these electrodes. Since it is possible to detect the time immediately before the turning of the steering wheel, it can be used as a turning start prediction signal of the steering wheel, and a change in the steering angle for turning the steering wheel can be secured for the time to enter the preparatory operation before the start of steering. It is possible to improve the responsiveness of the control system corresponding to the change in the steering angle. Further, since the pressure of the palm holding the ring portion can be detected at a plurality of points, the purpose of applying the pressure of the palm holding the ring portion can be properly known.

[Brief description of drawings]

FIG. 1 is a plan view of an essential part of a ring portion of a steering wheel according to an embodiment of the present invention.

FIG. 2 is a sectional view of an essential part of a ring portion of a steering wheel according to an embodiment of the present invention.

FIG. 3 is an electrode side development view of an inner flexible substrate used in the steering wheel of the embodiment of the present invention shown in FIG.

4 is a development view of a lead wire side of an inner flexible substrate used in the steering wheel of the embodiment of the present invention in FIG.

FIG. 5 is an electrode side development view of an outer flexible substrate used in a steering wheel according to an embodiment of the present invention.

FIG. 6 is a development view of a lead wire side of an outer flexible substrate used for a steering wheel according to an embodiment of the present invention.

FIG. 7 is an output characteristic diagram of the right pressure sensor in the right lane change test in the steering wheel according to the embodiment of the present invention.

FIG. 8 is a circuit diagram of electronic control means for driving and controlling an electric power steering apparatus using a steering wheel according to an embodiment of the present invention.

FIG. 9 is a flow chart of a control program executed by a power steering microcomputer according to an embodiment of the present invention.

FIG. 10 is a circuit diagram of an electronic control circuit that controls a conventional electric power steering system.

FIG. 11 is a flow chart of a main program for controlling a conventional electric power steering system.

[Explanation of symbols]

 1 Steering Wheel Main Body 2 Ring Part 10 Inner Flexible Board 11 Electrode 20 Outer Flexible Board 21 Electrode 30 Pressure Sensitive Conductive Rubber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chiharu Totani 1 Ochiai, Nagahata, Kasuga-cho, Nishikasugai-gun, Aichi Toyoda Gosei Co., Ltd. Toyoda Gosei Co., Ltd.

Claims (1)

[Claims] 1. A steering wheel having a pressure sensor embedded in a ring portion for detecting a pressure of a palm gripping the ring portion, wherein the pressure sensor includes a linear electrode extending in a specific direction of a substrate and the electrode. A steering wheel comprising: another linear electrode facing a surface and extending in a direction intersecting with the electrode; and a pressure-sensitive conductor interposed between the surfaces of the electrode.