JPH04146866A - Brake device for vehicle - Google Patents

Abstract

PURPOSE:To dispense with supplying power from a battery by constituting a brake operation means from a first piezoelectric laminated body to convert a brake pedal steeping force into an electric energy and a wheel brake means from a second piezoelectric laminated body to convert the electric energy into a braking force respectively. CONSTITUTION:Each of electrostriction laminated bodies 26 (a-d) is constituted by laminating a plural number of piezoelectric ceramic thin plates with an electrode sandwiched between them, and when it receives a stepping force from a brake pedal 12, electric charge is generated and supplied to each of circuits A-D. The circuit A is, for example, connected to a wheel braking mechanism 60 installed on the right rear wheel, and this wheel braking mechanism 60 is provided with electrostriction laminated body 60 consisted with piezoelectric ceramic thin plates laminated with an electrode sandwiched between them as the electrostriction laminated body 26 by way of steeping on the brake pedal 12 is condensed in each of the electrodes of the electrostriction laminated bodies 62 and generates high voltage between the electrodes, this electrostriction laminated bodies 62 are instantly expanded so that a braking force is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle braking device that brakes a vehicle using electrical energy.

[Conventional technology]

As a braking device that brakes the rotation of the wheels, is the detection signal detected by a sensor inputted to an electric circuit, and based on that detection signal, a command signal is output to the electric circuit or the braking device to operate the sub-device? Are known.

The braking device described in Japanese Patent Application Laid-Open No. 62-258844, shown in FIG. 6, is one example.

In this braking device, the output signal of a pedal force sensor 119 that detects the pedal force of the brake pedal 101 via the oil chamber 117 of the cylinder case 111, the start switch detection sensor 502, the wheel speed sensor 181, and the acceleration sensor 183 are used.
, each output signal detected by the pressure sensor 503 is input to the control circuit 331, and this control circuit 331
A control signal is transmitted to the electrostrictive element 311 of the master cylinder 201 via a conductive wire 333.

Further, when the control circuit 331 confirms that the pressure in the accumulator 145 is insufficient based on the pressure signal from the pressure sensor 503 when the ignition SW 501 is OFF, it transmits a drive signal to the motor 143 to increase the pressure in the accumulator 145 to a predetermined value. The pressure is increased to prevent accidental movement of the vehicle when parking on a slope.

The master cylinder 201 expands and contracts the electrostrictive element 311 in response to a control signal output from the control circuit 331, thereby moving the small piston 291 and the spool 276 in the left-right direction in the figure.

As a result of this movement, communication between the pressure chamber 271 and the pressure input port 207 or the pressure release boat 213 is disconnected from or communicated with the inside of the master cylinder 201, resulting in a change in the volume of the pressure chamber 271.

From this, when the movable piston 241 moves to the left in the figure, the pressure release boat 213 closes, the oil pressure in the pressurizing chamber 255 is increased, and the pressure is increased via the foil cylinder 161b.
Braking pressure is supplied to the wheels.

Furthermore, when the movable piston 241 moves to the right in the figure, the pressure release boat 213 opens, the oil pressure in the pressurizing chamber 255 is reduced, and the braking pressure of the wheels is reduced via the foil cylinder 161b.

[Invention or problem to be solved]

However, in this braking device, the ignition switch
502 is OFF, the pressure sensor 503 causes the mask cylinder 201 to be removed from the accumulator 145.
When the control circuit 331 confirms that there is insufficient pressure to be supplied to the pump 141 and outputs a drive signal to the electric motor 143 based on that information, the electric motor 143 that received the drive signal from the control circuit drives the pump 141. Since this is a system that supplies hydraulic pressure to the master cylinder 201, if the battery voltage is insufficient, there is a risk that the hydraulic pressure supplied to the master cylinder 201 may be insufficient.

In view of the above, an object of the present invention is to provide a braking device that can obtain braking force without requiring a battery power source.

[Means to solve the problem]

In order to achieve the above-mentioned problems, the present invention obtains braking force by converting the amount of work required for a brake pedal operation into electrical energy and operating a braking device with the electrical energy. In order to solve this problem, as shown in FIG.
In the vehicle braking system, the brake operating means 100 includes a brake operating means 100 having the brake pedal 1 and a wheel braking means 60 provided for each wheel.
The wheel braking means 60 has a first piezoelectric laminate 26 made of a stack of a plurality of piezoelectric elements that converts the stepping force applied to the pedal 2 into electrical energy, and the wheel braking means 60 inputs the electrical energy and converts it into braking force. It is characterized by comprising a second piezoelectric laminate 62 made of a laminate of a plurality of piezoelectric elements.

[Effect]

According to the above means, the brake pedal 12 is controlled by the rider.
When the operation is performed, the I-th of the brake operating means 100
The depression force applied to the brake pedal 12 is converted into electrical energy by the piezoelectric laminate 26 of the wheel braking means 60, and the electrical energy is input to the second piezoelectric laminate 62 of the wheel braking means 60. is displaced and generates a braking force to brake the wheels.

〔Example〕

Hereinafter, an example in which the present invention is applied to each wheel of a vehicle will be explained based on the drawings.

FIG. 1 is a diagram schematically showing the overall configuration of a braking device according to a first embodiment of the present invention.

The brake pedal 12 is connected to the driver's seat of the vehicle 10 and the shaft 16.
The brake pedal 12 is rotatably fixed.
It is connected to the bar 14 by a shaft 18. Further, a spring 20 is connected to the vehicle IO near the shaft 18 of the brake pedal 12, and applies a negative force to the brake pedal 12 in the right direction in the figure (depression force release direction).

A flat plate 22 is formed at the other end of the bar 14.

The plate 22 is disposed inside a case 24 made of an insulator, and the electrostrictive laminate 26b inside the case 24,
26d.

The case 24 is partitioned into internal parts 25a and 25b, and the internal part 25a has electrostrictive laminates 26a and 260, and the internal part 25a has electrostrictive laminates 26a and 260.
The electrostrictive laminates 26b and 266 are housed in series with an insulator 28 in between.

Each electrostrictive laminate 26 (a, b, c, d) is made by laminating a plurality of piezoelectric ceramic thin plates with electrodes in between, and is polarized in one direction.

The electrostrictive laminate 26 (a, b, c, d) undergoes crystal distortion by receiving pedal force from the brake pedal 12.
Polarization of positive and negative charges occurs, and when the charges are discharged,
Each electrostrictive laminate 26 (a, b, c,
Each charge generated in d) is transferred to circuits A, B,
C and D (brake operation means 100).

Further, the electrostrictive laminate 26. (a, b, c, d) expands when a charge is applied between the electrodes.

The electrostrictive laminate 26 is supplied with charges accumulated in the electrostrictive laminate 62 (a, b, c, d) provided in the wheel braking mechanism 60, and is also supplied with the brake pedal 12 as described later. When the pedal force is released, the earth switch 32 or the plate 22 moves to the right in the figure against the elastic force of the spring 36, turning on the earth 34 and the electrostrictive laminate 26 (a, b, c, d) are connected to the diode 38
It expands when a charge is supplied through it.

Note that the circuit A is connected to a wheel braking mechanism 60, which will be described later, installed on the right rear wheel (not shown), and the circuit B and the circuit C
Each circuit is similarly connected to the front right wheel, the rear left wheel, and the front left wheel.Here, circuit A will be explained as an example, and the configurations of circuits B, C, and D will be omitted.

The electrostrictive laminate 26a is connected to the terminals a of the switches S1 and S3 of the switch circuit 1.3 by electric wires 42, 44, and constitutes either normal braking means or abnormal braking means described below.

The normal braking means for actuating the anti-lock brake system includes switches Sl, S3 and switches S2, S4 of a switch circuit 2.4, which will be described later.
, S4 are energized, and each switch is connected to each terminal a on the left side in the figure.

Therefore, the electric wire 42 and the electric wire 48, and the electric wire 43 and the electric wire 49 are connected, and the electric charge generated by the pedal force, which will be described later, is input to the control circuit 40.

The control circuit 40 includes a piezoelectric element drive circuit 41 that applies a high voltage to the electrostrictive laminate 62 of the wheel braking mechanism 60, a battery 50 installed in the wheel braking mechanism 60, a vehicle speed sensor 51, and detects the wheel speed. It is connected to the wheel speed sensor 52 and to the switch circuit 1.2.3.4.

The control circuit 40 includes a CPU, ROM, and RAM (not shown) that operates an anti-lock brake, which will be described later.
a second microcomputer that monitors abnormalities in the first microcomputer, and a charge that detects the amount of charge movement output from the electrostrictive laminate 26a and outputs the detected charge to the microcomputer. It includes a detection circuit, a waveform shaping circuit that shapes the waveforms of the output signals of the vehicle speed sensor 51 and the wheel speed sensor 52, and an excitation current output circuit that outputs a DC excitation current to the switch circuit 1.2.3.4. .

Note that the charge detection circuit is grounded to earth (not shown), and when the electrostrictive laminate 26a is insufficient in charge, the charge is supplied to the electrostrictive laminate 26a by the ground.

The piezoelectric element drive circuit 41 is not shown, or inputs the voltage of the battery 50 and applies a high voltage to a high voltage power supply circuit that converts it into a high voltage power supply and the electrostrictive laminate 62 of the wheel braking means 60. A high voltage application circuit is provided, and the high voltage application circuit is electrically connected to the electrostrictive laminate 62 through electric wires 50 and 45 and electric wires 51 and 43.

In the normal braking means constructed as described above, when the plate 22 is moved to the left in the figure by operating the brake pedal 12, an electric charge is generated by the electrostrictive laminate 26a, and is transmitted to the control circuit 40 via the electric wires 48 and 49. Move to the charge detection circuit.

The control circuit 40 determines the voltage pre-stored in the CPU of the first microcomputer and the value of the braking force (command voltage) applied from the braking cap to the electrostrictive laminate 62 based on the amount of charge movement detected by the charge detection circuit. Calculate and store.

In addition, when calculating the value of the command voltage using the map, the value of this command voltage is determined by detecting whether or not the action of stepping on the brake pedal is performed from the initial state, and if it is not an initial action, the value of the command voltage is calculated from the previous calculation. This is integrated into the value of the command voltage, which is converted into a high voltage by the piezoelectric element drive circuit 41 and output to the electrostrictive laminate 62, thereby braking the wheels.

The first microcomputer constantly monitors the wheel rotation speed using the wheel speed sensor 52, and if the wheel rotation speed decreases by more than a predetermined value due to wheel braking,
It is determined that the wheels are locked, and the command voltage value is set to a predetermined value β.
The value of the command voltage is corrected and output by subtracting the value.

Note that the predetermined value β is determined by the CPU of the first microcomputer.
The magnitude of the predetermined value β is set according to the wheel rotation speed and vehicle speed detected by the vehicle speed sensor 5 and the wheel speed sensor 52 using the wheel rotation speed, vehicle speed, and voltage map stored in advance. be.

The anti-lock brake system is activated by the above control.

Next, when there is an abnormality in the first microcomputer or the voltage of the battery 50, the second microcomputer detects the abnormality, and the switch circuits 1.2.
3. Stop supplying DC excitation current to 4.

Therefore, Sl, S2, S3, and S4 of each switch circuit are
Moving to the right in the figure (terminal b), wires 42 and 44 are connected to S
1, communicates with electric wire 43.45 via S3, and
S2 and S4 are connected to ground.

This constitutes an emergency brake circuit in which the electrostrictive laminate 26a and the electrostrictive laminate 62 are in direct communication.

Note that, like the electrostrictive laminate 26, the electrostrictive laminate 62 is made by laminating piezoelectric ceramic thin plates with electrodes in between and is polarized in one direction, so that it expands when a positive voltage is applied, and becomes a negative polarizer. It contracts when voltage is applied.

For this reason, the brake pedal 1 is
When the electrostrictive laminate 26a and the plate 22 move to the left in the figure, charges are generated by the electrostrictive laminate 26a.

The electric charge generated by polarization moves to the electrostrictive laminate 62 of the wheel braking mechanism 60 via the electric wires 42 and 43, and is stored in each electrode of the electrostrictive laminate 62, generating a high voltage between the electrodes. let

Therefore, the electrostrictive laminate 62 instantly expands and generates a braking force.

Next, when the brake pedal 12 is maintained in a state in which it is moved to the left in the figure, the electrostrictive laminate 2 is moved by the plate 22.
6a is similarly maintained in a contracted state.

Therefore, the charge that moves when the electrostrictive laminate 26a contracts is
It is stored in the electrostrictive laminate 62, and the electrostrictive laminate 26a maintains the expanded state to ensure braking force.

Next, when the pedal force is weakened and the brake pedal moves from the left to the right in the figure, the plate 22 releases the pressure on the electrostrictive laminate 26a and moves to the right in the figure.

Therefore, the electrostrictive laminate 26a absorbs charges from the electrostrictive laminate 60 and expands.

Furthermore, the electrostrictive laminate 60 contracts depending on the amount of absorbed charge due to the absorption of charges by the electrostrictive laminate 26a.

In addition, in the brake circuit at the time of an abnormality, when the brake pedal 12 is operated and the charge is transferred or repeated between the electrostrictive laminate 26a and the electrostrictive laminate 60, energy loss occurs, and the electrostrictive laminate Since an error occurs in the distance by which the electrostrictive laminates 26a and 60 extend and contract, a means is provided to apply an electric charge to the electrostrictive laminate 26a1 and the electrostrictive laminate 62 to extend them when the depression force on the brake pedal 12 is released.

That is, the extending means means that when the pressing force of the brake pedal 12 is released, the earth switch 32 or the plate 22 moves to the right in the figure against the elastic force of the spring 36.
It becomes ON state and connects the ground 34 and the electrostrictive laminate 26 (a, b
, c, d) are connected via a diode 38 to supply charge to the electrostrictive laminate 26 (ab, c, d).

FIG. 2 is a diagram showing an embodiment of a wheel braking mechanism.

The axle 66 is equipped with a brake disc 68 or a hub nut 7.
Axle hub 7 rotatable integrally with axle 66 by 0
It is attached to 2. Further, a brake housing 74 is attached to the axle 66 via a bearing (not shown).

Inside the brake housing 74, an electrostrictive laminate 62 is disposed so as to expand and contract in the axle direction. The electrostrictive laminate 62 has piezoelectric ceramic thin plates stacked in a cylindrical insulating case 63 with electrodes in between, similar to the electrostrictive laminate 26 .

Both ends of the insulating case 63 are provided with pressing plates 76a made of an insulating material.
, 76b, and is installed to be slidable with the insulating case 63.

Projections 78a and 78b protrude from the outside of the pressing plates 76a and 76b, and abut against the arms 80a and 80b.

The arms 80a and 80b have a rotating shaft 82a at the end on the axle side,
82b is rotatably fixed to the brake housing 74, and a coil spring 84 is installed between the other ends of the arms so that the arms 80a, 80b are maintained perpendicular to the axle direction.

Projections 85a and 85b are formed on the outside of the other end of the arm and abut against caliper 86a and caliper 86b.

The caliper 86a has a groove 88 formed in the brake housing 74 between the brake disc 68 and the arm 80a.
A is placed in a slidable manner, and a brake pad 90a is attached to the caliper 86a side on the brake disc 68 side.

On the other hand, one end of the caliper 86b formed in a C-shape is
It opposes a caliper 86a via a brake disc 68, and a brake pad 90b is attached thereto. The other end of the caliper 86b is slidably placed in a groove 88b formed in the brake housing 74 on the arm 80b side.

A predetermined space is placed between the brake pads 90a, 90b and the brake disc 68.
Braking force is generated after this predetermined space becomes zero.

The relationship between the pedal force and the braking force depends on the setting of a predetermined space and when the electrostrictive laminate 62 is extended, the protrusions 78a, 78b or the arm 8
Setting of positions for pressing 0a and 80b and electrostrictive laminate 26
a, the size of the electrostrictive laminate 60, and the shaft 18 of the brake pedal 12.

Figure 3 shows the brake circuits B and D in the case of abnormality in the first embodiment.
FIG. 3 is a schematic diagram of an application example in which braking characteristics are changed by connecting an electric circuit between electric wires 42 and 43 and between electric wires 44 and 45 (on the rear wheel side).

4(I), (II), and (I[[) are electrical circuits connected to FIG. 3, and the method of changing the brake characteristics will be explained using each figure.

Note that since the circuits B and D have the same configuration, the explanation of the circuits will be omitted in the following explanation. Furthermore, explanations of configurations that overlap with the brake circuit described above will be omitted.

FIG. 4(I) shows a means for setting the relationship between the stroke amount S1 of the brake pedal 12 and the extension amount S2 of the electrostrictive laminate 62b by installing a Zener diode 92a between the electric wires 42 and 43.

By depressing the brake pedal 12 to the left in the figure, the charge from the electrostrictive laminate 26 moves from the electric wire 42 side toward the Zener diode 92a.

When a small amount of charge moves, i.e. Zener diode 9
When the voltage between 2 and a is low, the Zener diode 9
Since it is difficult for the charges 2a to pass through, the amount of expansion S2 of the electrostrictive laminate 62b is lower than the characteristics of the circuit A described above.

When a certain amount of charge movement is exceeded, that is, when the voltage across the Zener diode 92a is high, an avalanche phenomenon occurs in the Zener diode 92a and a large amount of charge starts to move, so that the amount of expansion of the electrostrictive stack 62b increases. S2 has a value close to the characteristic (2) when the electric circuit is not used, and the characteristic curve shown in FIG.

In FIG. 4 (I[), the capacitor C1 and the ground are connected in series between the electric wires 42 and 43, and the relationship between the stroke amount S1 of the brake pedal 12 and the expansion amount S2 of the electrostrictive laminate 62b is set. It is a means to do so.

When the charge moves from the electric wire 42 to the electric wire 43 side, the electric charge
The electric wire 43 moves to the electrostrictive laminate 62b, and a part of it is charged to the capacitor C1.

Since the electric charge is gradually applied to the electrodes of the capacitor, the amount of expansion S2 of the electrostrictive laminate 62b becomes relatively smaller than the characteristic curve (■) when no electric circuit is used, and the characteristic curve (■) in FIG. 5 is obtained. .

FIG. 4 (III) shows that a Zener diode 92b, a capacitor C2, and a ground are connected in series between electric wires 42 and 43, and then branched, thereby increasing the stroke amount S1 of the brake pedal 12 and the expansion amount of the electrostrictive laminate 62b. This is means for setting the relationship of S2.

Until the amount of charge transfer reaches a certain amount, that is, the electric wire 42.4
Since the avalanche effect does not occur until the potential difference between 3 and the Zener diode 92b reaches a certain value, the electrostrictive stack 6
The expansion amount S2 of 2b is almost the same as the characteristics of circuit A,
When the amount of charge movement exceeds a certain amount, the charges flow toward the ground side, and the amount of expansion S2 of the electrostrictive laminate 62b becomes relatively smaller than the characteristic (2) when no electric circuit is used.

From the above, it becomes possible to freely set the braking characteristics of the front wheels and rear wheels.

In addition, the pedal force required to operate the brake pedal is converted into electrical energy by the electrostrictive laminate (brake operating means), and the electrician's leek is converted into the electrostrictive laminate of the wheel braking mechanism (wheel braking means). By energizing it, it is possible to obtain braking characteristics with even faster response than hydraulic brakes.

Furthermore, the pedal force required to operate the brake pedal is converted into electrical energy by the electrostrictive laminate (brake operating means), and the electrician's onion is energized to the electrostrictive laminate of the wheel braking mechanism (wheel braking means). This eliminates the need for an oil reservoir installed in hydraulic brakes, reducing the space in the engine room and eliminating the need for oil replenishment.

〔Effect of the invention〕

According to the present invention, when a brake pedal is operated by a tower rider, the first piezoelectric laminate of the brake operating means converts the depression force applied to the brake pedal into electrical energy, and the electrical energy is converted into electrical energy. is inputted to the second piezoelectric laminate of the wheel braking means, and the input electrical energy enables the second piezoelectric laminate to expand and generate a braking force to brake the wheel. , it becomes possible to brake the rotation of the wheels by the amount of work required for the rider on the tower to operate the brake pedal, without requiring power supply from the battery.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the overall configuration of a braking device according to a first embodiment of the present invention. FIG. 2 is a diagram showing an embodiment of a wheel braking mechanism. FIG. 3 is a schematic diagram of an application example of changing the braking characteristics of the brake circuit in the event of an abnormality in the first embodiment. (I), (II), and (III) in FIG. 4 are electrical circuit diagrams connected to FIG. 3. Figure 5 shows (I), (It), (1) in Figure 4.
FIG. 3 is a diagram showing the relationship between electrostrictive laminates when used in a brake circuit during an abnormality. FIG. 6 shows the prior art. Explanation of symbols 1, 2. 3. 4 Sl, S2. S10・Vehicle, 1 22, Plate switch circuit 3, S4・Switch 2 Brake pedal 24: Inside of case 25a, 25b 32: Earth switch 34: Earth 38. Diode 40: Control circuit
41: Piezoelectric element drive circuit 50: Battery 52: Wheel speed sensor 60: Wheel braking mechanism 62: Strained laminate 6
3. Insulating case 66: Axle 68/brake disc 70: Hub nut 74: Housing 76a, 76b
: Pressing plates 78a, 78b: Projections 80a, 80b: Arms 82a, 82b: Rotating shaft 84: Coil springs 85a, 85b: Projections 86a, 86b: Calibers 88a, 88b: Grooves 90a, 90b Brake pads 92a, 92b: Zener diode

Claims (1)

[Scope of Claims] In a vehicle braking device having a brake operating means having a brake pedal and a wheel braking means provided for each wheel, the brake operating means converts the depression force applied to the brake pedal into electrical energy. The wheel braking means has a first piezoelectric laminate made of a laminate of a plurality of piezoelectric elements that convert the electric energy into a braking force, and the wheel braking means has a second piezoelectric laminate made of a laminate of a plurality of piezoelectric elements that input the electrical energy and convert it into braking force. A vehicle braking device comprising a piezoelectric laminate.