JPS6114026B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-skid device for a vehicle that controls brake fluid pressure applied to a wheel according to the rotational state of the wheel.

Conventionally, anti-skid devices for vehicles detect the rotational speed of the wheels by using a wheel consisting of a rotor that rotates together with the wheel and has a large number of teeth on its outer periphery, and a pickup that generates an electrical signal each time the teeth of the rotor pass. a speed detector; and a control unit that receives a signal from the wheel speed detector and issues a command to reduce, maintain, or increase the brake fluid pressure supplied to the wheel cylinder of the wheel depending on the skid state of the wheel. , a hydraulic pressure control device that lowers, maintains, or increases brake fluid pressure to the wheel cylinders in accordance with commands from a control unit. and a type in which the hydraulic pressure control device has a hydraulic pump, that is, a shutoff valve that shuts off between the master cylinder and the wheel cylinder, and a volume increase mechanism that increases the volume between the shutoff valve and the wheel cylinder. The hydraulic pressure of the servo device to operate the volume increase mechanism is obtained by a hydraulic pump, or the hydraulic pressure is temporarily transferred to a reservoir by a solenoid valve to reduce the hydraulic pressure of the wheel cylinder. In the case where the brake fluid in the reservoir is pressurized by a hydraulic pump and returned to the pressure line of the master cylinder, a motor or the like is used to drive the hydraulic pump. Therefore,
The entire device was large and required many components.

The present invention drives a hydraulic pump of a hydraulic pressure control device by wheels whose brake fluid pressure is controlled by the hydraulic pressure control device, and converts the pulse pressure generated in the hydraulic pump through a pressure electrical signal converter. An object of the present invention is to provide an anti-skid device for a vehicle which detects the electrical signal as an electrical signal and uses the electrical signal as a wheel rotational speed signal, and thereby provides a wheel speed detector for detecting the rotational speed of the wheel. Since there is no need to provide a separate pump and a motor for driving the hydraulic pump, the entire device can be downsized and the structure can be simplified.

Embodiments of the present invention will be described in detail below with reference to the drawings.

A master cylinder 1 is connected to a wheel cylinder (not shown) of a wheel brake via a pipe 2a, electromagnetic valves 3 and 4, and a pipe 2b. Reference numeral 5 denotes a hydraulic pump, which rotates together with the wheels, is driven by a rotor 7 having a large number of cam surfaces 6 formed on its outer periphery, and is equipped with a pressure electrical signal converter 8. The hydraulic pump 5 and the electromagnetic valves 3 and 4 constitute a hydraulic control device.
9 receives the signal from the pressure electric signal converter 3, determines whether the wheel connected to the rotor 7 is skidding or about to skid, and reduces and maintains the brake fluid pressure supplied to the wheel cylinder of that wheel. , or a control unit for actuating the solenoid valves 3 and 4 for lifting. 10 is a power source.

Next, the structure of the hydraulic pump 5 will be explained.

Reference numeral 11 denotes the main body of the hydraulic pump 5, which is provided with holes 12 and 13 that open downward in the figure.
A piston 15 having a cylinder hole 14 therein is slidably inserted into the hole 12, and a chamber 17 is formed above the piston 15 to be connected to the pressure line 2 of the master cylinder 1 via a connection port 16. ing. A piston 18 is slidably inserted into the hole 13, and a reservoir chamber 19 is formed above the piston 18. A plunger 20 is slidably inserted into the cylinder hole 14 of the piston 15, and a seal member 21 is attached to the upper part of the plunger.
A pressure generating chamber 22 is formed above 1. Further, the plunger 20 has a leg portion extending downward, and a roller 23 that engages with the cam surface 6 of the rotor 7 is provided at the lower end of the leg portion. 24 is a spring that presses the piston 15 upward when no hydraulic pressure is applied to the chamber 17, and 25 is a stopper that causes the piston 15 to move downward when the hydraulic pressure is transmitted from the master cylinder 1 to the chamber 17. The lower position is determined when 26 and 27 are seal rings. A spring 28 presses the plunger 20 downward and brings the roller 23 into contact with the cam surface 6. A stopper 29 determines the lower limit position of the plunger 20 relative to the piston 15. 30 is a hydraulic pressure generation chamber 22
This is a hole provided in the piston 15 to communicate with the liquid passage 31. Reference numeral 13a is a cover that closes the lower opening of the hole 13, and a switch 32 that closes the contact when the piston 18 moves downward by a predetermined distance is screwed into the center of the cover 13a. Reference numeral 33 denotes a spring stretched between the piston 18 and the cover 13a, which causes the brake fluid in the reservoir chamber 19 to reach a predetermined level, for example, 3.
It applies a residual pressure of Kg/cm ² . 34 is a seal ring. Reference numeral 35 denotes a suction valve, which is arranged between the reservoir chamber 19 and the hydraulic pressure generation chamber 22. Further, 36 is a discharge valve, and the hydraulic pressure generating chamber 22
The hydraulic pressure generated inside the pipe 2a is passed through the connection port 37.
In other words, it acts to send the pressure to the pressure line of the master cylinder 1. 38 is a ball valve 39 and a valve spring 4
This is a check valve consisting of 0. Reference numeral 41 denotes a two-way solenoid valve, which is disposed between the connection ports 42 and 43 as a bypass valve. When the amount of liquid in the reservoir chamber 19 exceeds a predetermined amount due to the operation of the electromagnetic valve 4, which will be described later, and the switch 32 is operated, the connection between the connection ports 42 and 43 is cut off.

The pressure electrical signal converter 8 is screwed onto the main body 11, and its lower end detection portion protrudes into a chamber 45 connected to the hydraulic pressure generating chamber 22 via a passage 31.
This pressure electrical signal converter converts, for example, a pressure change into an electrical resistance change, and an electrical signal corresponding to a pressure change in the chamber 45 is transmitted to the control unit 9 via a wiring 46. 47, 48
is the wiring between the control unit 9 and the solenoid valves 3 and 4, and 49 is the wiring for the power supply.

Next, the operation of the embodiment will be explained.

When the vehicle is running, the rotor 7 is rotating together with the wheels. Before the brake is applied, no electric signal hydraulic pressure is generated in the master cylinder 1, and the chamber 17 of the hydraulic pump 5
is pressureless. Therefore, the plunger 20 is connected to the spring 2
Although the piston 15 is pushed downward by the spring 24, the piston 15 is pushed upward by the spring 24.
The roller 23 of the plunger 20 is spaced from the cam surface 6. That is, when the brake is not applied, the hydraulic pump 5 does not operate.

Now the brake is applied and the master cylinder 1
When the brake fluid pressure generated in
The roller 23 is pressed against the cam surface 6 of the rotor 7, and the plunger 20 starts to move up and down according to the unevenness of the cam surface 6. First, when the plunger 20 is pushed upward by the cam surface 6, the liquid in the liquid pressure generating chamber 22 is pressurized, and the pressure is sent to the liquid passage 31 through the hole 30. This hydraulic pressure is supplied to the reservoir chamber 19 through the check valve 38 and the solenoid valve 41, and is also supplied to the lower surface of the discharge valve 36. However, the set tension of the spring 24 is set so that the hydraulic pressure in the chamber 17 that causes the piston 15 to move downward is greater by a predetermined value, for example, 2 kg/cm ² than the residual pressure in the reservoir chamber 19 provided by the spring 33. Therefore, the pressure liquid generated in the hydraulic pressure generation chamber 22 overcomes the hydraulic pressure from the master cylinder 1 acting on the upper surface of the discharge valve 36, opens the discharge valve, and is discharged into the pressure line of the master cylinder 1. The water is supplied only to the reservoir chamber 19. Therefore, the piston 18 moves downward against the spring 33, and the brake fluid sent out from the hydraulic pressure generating chamber 22 flows into the reservoir 19.
flow inside. The distance between the upper end of the operating rod of the switch and the lower surface of the piston 18 is determined so that the switch 32 will not operate depending on the amount of downward movement of the piston 18 at this time.

Next, when the rotor 7 rotates a predetermined amount and the roller 23 comes to the concave position of the cam surface 6, the plunger 20
can be moved downward. Therefore, the plunger 2 is moved by the pressing force of the spring 28 in the hydraulic pressure generating chamber 22 and the hydraulic pressure from the reservoir chamber 19 having residual pressure sent to the hydraulic pressure generating chamber 22 through the suction valve 35.
0 moves downward, and the liquid in the reservoir chamber 19 is returned to the hydraulic pressure generating chamber 22 again. This plunger 20
During the downward stroke of , the hydraulic pressure transmitted from the reservoir chamber 19 to the hydraulic pressure generating chamber 22 is not a residual pressure because the expansion speed of the hydraulic pressure generating chamber 22 is sufficiently high except when the rotation of the rotor 7 is at an extremely low speed. The value is much lower than that. Therefore, as the rotor 7 rotates, during the upward stroke of the plunger 20, a hydraulic pressure equal to the residual pressure defined by the spring 33 is also applied to the plunger 20.
During the zero downward stroke, a hydraulic pressure approximately equal to zero appears. In other words, the number of fluid pressure changes (pulsation pressure) corresponds to the unevenness of the cam surface provided on the outer periphery of the rotor 7.
occurs.

Note that if it is necessary to increase the fluid pressure change when the rotor 7 is running at an extremely low speed, the tension of the valve spring 40 of the check valve 38 is increased, for example, 5.
The check valve 38 may be opened only when a hydraulic pressure of Kg/cm ² or more is generated in the hydraulic pressure generating chamber 22.

The fluid pressure change in the fluid pressure generation chamber 22 generated in this manner is transmitted to the chamber 45, converted into an electrical resistance change by the pressure electrical signal converter 8, and transmitted to the control unit 9 via the wiring 46.

Therefore, when the brake is applied and a predetermined hydraulic pressure is generated in the master cylinder 1, from that point on, a change in electrical resistance with a frequency proportional to the number of rotations of the wheel is transmitted to the control unit 9. The wheel speed is detected by the frequency detection circuit.

When the brake is strongly depressed, skidding occurs in the wheels and the rotational speed of the wheels suddenly decreases, the rotational speed of the rotor 7 decreases accordingly, and the frequency of the pulsation pressure within the hydraulic pressure generating chamber 22 decreases. The reduction in frequency is transmitted to the control unit 9 by the pressure-electrical signal converter 8. Then, in the control unit 9, the magnitude of the wheel deceleration is determined.
When it is determined that the brake fluid pressure has exceeded a predetermined value, a brake fluid pressure reduction signal is generated, and the solenoid valves 3 and 4 are operated via the wirings 47 and 48.

Therefore, the hydraulic pressure from the master cylinder 1 is cut off by the solenoid valve 3, and the brake pressure fluid supplied to the wheel cylinder by the solenoid valve 4 is transferred to the piping 2b, the solenoid valve 4, and the connection port 43. The fluid is removed through the reservoir chamber 19, and the hydraulic pressure at the wheel decreases.

When the brake fluid removed from the wheel cylinder is sent to the reservoir chamber 19, the fluid causes
The piston 18 moves significantly downward, and the switch 3
2 is activated. The operation of this switch 32 causes the solenoid valve 41 to operate, thereby cutting off communication between the connection ports 42 and 43.

Therefore, the liquid sent out from the hydraulic pressure generating chamber 22 due to the upward movement of the plunger 20 no longer reaches the check valve 38.
Since it cannot flow into the reservoir chamber 19 through the discharge valve 36, the pressure becomes sufficiently high and it is sent into the pressure line of the master cylinder 1 through the discharge valve 36. When the plunger 20 descends, the reservoir chamber 19
The brake fluid inside flows into the hydraulic pressure generating chamber 22 through the suction valve 35.

That is, the hydraulic pump 5 acts to pressurize the brake fluid in the reservoir 19 and return it to the pressure line of the master cylinder 1.

Naturally, even during this period, pressure changes within the hydraulic pressure generating chamber 22 as the rotor 7 rotates are detected by the pressure electrical signal converter 8 and sent to the control unit 9. When the hydraulic pressure in the wheel cylinder decreases and the wheel rotation speed begins to recover,
A brake fluid pressure maintenance command is issued from the control unit 9, the solenoid valve 4 is returned to the non-operating position, and the fluid pressure in the wheel cylinder is kept constant. Then, when the wheel rotational speed recovers to approximately the vehicle body speed, the solenoid valve 3 also returns to the non-operating position, the hydraulic pressure of the master cylinder 1 is again supplied to the wheel cylinder, and the hydraulic pressure of the wheel cylinder increases.

The brake fluid discharged into the reservoir chamber 19 is then discharged from the discharge valve 36 every time the plunger 20 moves up and down.
The piston 18 is returned to the piping 2a and reduced, thereby causing the piston 18 to rise, the switch 32 to return to the non-operating position, and the solenoid valve 41 to be in the communicating state. Therefore, the above-described circulation movement of the liquid between the hydraulic pressure generating chamber 22 and the reservoir chamber 19 starts again.

When the fluid pressure in the wheel cylinder increases and the wheels begin to skid again, the brake fluid pressure is reduced, maintained, or increased in the same way as described above, and by repeating this process, the wheel slip ratio is optimized. controlled.

When the brake is released, the brake fluid pressure in the wheel cylinder decreases, and the fluid pressure in the chamber 17 of the hydraulic pump 5 also decreases. Therefore, piston 15
is pushed upward by the spring 24, the roller 23 is separated from the cam surface 6 of the rotor 7, and the operation of the pump 5 is stopped. Therefore, the pump 5 operates only when hydraulic pressure is generated in the master cylinder 1, and when the pump 5 operates, it does not matter whether the hydraulic pressure of the wheel cylinder is being controlled or not. , continues to generate pulsating pressure according to the rotational speed of the rotor 7, and the pulsating pressure is constantly sent to the control unit as an electrical signal via a pressure-electrical signal converter, and is used as a wheel rotational speed signal.

Note that in the above embodiment, the pressure electric signal converter 8
is provided in the main body 11 so that the detection part protrudes into the chamber 45 to which the pulse pressure from the hydraulic pressure generation chamber 22 is transmitted. may be provided.

As is clear from the above description, the rotor rotates together with the wheel, and the rotor can be engaged with the rotor.
a hydraulic pump that is driven by the rotation of the rotor and generates a pulsating pressure proportional to the number of rotations of the wheel; and a pressure-electrical signal converter that converts the pulsating pressure into an electrical signal in the pulsating pressure generating section or transmitting section. Since the electric signal converted by the pressure electric signal converter is used as the rotational speed signal of the wheel, the structure of the wheel speed detector is significantly simplified. This provides remarkable effects such as eliminating the need to provide a special power source for driving the pump.

Note that the present invention is not limited to the above-described embodiments, and the hydraulic pressure control device includes a hydraulic pump to control the brake fluid pressure of the wheels, and the hydraulic pump controls the rotation of the rotor that drives it. It is clear to those skilled in the art that any type of device that generates a pulse pressure corresponding to the pressure can be used.

[Brief explanation of the drawing]

The figure is a partial sectional view showing one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Master cylinder, 3, 4, 41... Solenoid valve, 5... Hydraulic pressure pump, 7... Rotor, 8... Pressure electric signal converter, 9... Control unit, 10
...Power source, 11...Main body, 14...Cylinder hole, 15,
18...Piston, 19...Reservoir chamber, 20...Plunger, 22...Liquid pressure generation chamber, 23...Roller, 3
2...Switch, 35...Suction valve, 36...Discharge valve, 3
8...Check valve.

Claims (1)

[Claims] 1. An anti-skid device for a vehicle, which detects the rotational speed of a wheel and controls the brake fluid pressure supplied to the wheel according to a change in the rotational speed by a hydraulic pressure control device having a hydraulic pump. A rotor that rotates together with the wheel, a hydraulic pump that is engageable with the rotor, is driven by the rotation of the rotor, and generates pulsating pressure proportional to the number of rotations of the wheel, and a generator or transmitter of the pulsating pressure. A pressure electric signal converter for converting the pulse pressure into an electric signal is included in the part, and the electric signal converted by the pressure electric signal converter is used as a rotational speed signal of the wheel. Anti-skid device for vehicles.