JPH01289749A - Antiskid device - Google Patents

Abstract

PURPOSE:To make any antiskid action by an actuator unable as well as to prevent an increase of leg-power to a brake pedal from occurring by closing a valve installed in a passage lying between a decompression space of the actuator and a reservoir at the time of four-wheel driving. CONSTITUTION:At the time of two-wheel driving, a cam 59 is rotated up to an illustrated position. If so, a piston 46 moves against a spring 54, so that a valve body 52 separates from a valve seat 51. In brief, since a valve 34 is open, and a pipeline 18 of an actuator 30 constituting an antiskid device body is interconnected to a reservoir 32 via the valve 34 and a passage 33, which actuator 30 performs an antiskid action. On the other hand, at the time of four-wheel driving, the cam 59 is rotated up to the opposite position. If so, the piston 46 is pressed by the spring 54, so that the valve body 52 takes the valve seat 51, closing the valve 34. Consequently, even if a wheel is locked and the actuator 30 starts its operation, hydraulic pressure in a decompression space 17 is not varied at all, thus the antiskid action is no longer performed.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a device for preventing skids from occurring during brake operation of a vehicle.

“Prior Art” Conventionally, skid prevention devices have been used in vehicles. This skid prevention device is installed in the middle of the conduit that transmits the pressure of brake fluid in the master cylinder operated by the brake pedal to the wheel cylinder of each wheel, and prevents the wheels from approaching a locked state due to sudden braking. By alternately depressurizing and pressurizing the brake fluid when doing so, the brake fluid is prevented from reaching a locked state and the braking distance is shortened.

Figures 8 to 12 show the previously filed patent application filed in 1982-
264206 shows the anti-skid device described in No. 264206.

This skid prevention device includes a lock detection section A that detects when a wheel approaches a locked state;
The hydraulic pressure modulating section B lowers the pressure of the brake fluid according to the detection of the brake fluid pressure, and the pump section C increases the decreased brake fluid pressure again.

In the above device, under normal operating conditions, as shown in FIG. 8, the piston 22° 22a of the pump section C is in the position shown in the same figure, and the piston 22° 22a of the pump section C is in the position shown in the same figure. The valve body 2 is pushed down by the piston 3, and communicates the passage 4 connected to the master cylinder with the passage 5 connected to the wheel cylinder. When brake fluid is supplied from the cylinder to the passage 4, the brake fluid is sent to the passage 5 via the introduction chamber 6 of the pump section C, the communication passage 7, and the valve chamber (■), and is supplied to the wheel cylinder to be in a braking state. becomes.

Also, if the wheels become nearly locked due to sudden braking,
In the lock detection section A, a flywheel 10 connected via a ball ramp mechanism 9 to a rotating shaft 8 rotating in conjunction with the wheel creates a speed difference between itself and the rotating shaft 8 due to its own inertia. , can be moved to the left in FIG.

That is, the ball ramp mechanism 9 has a plurality of spherical recesses facing each other in an annular block 12 supported by the rotating shaft 8 via a plate 11 and a flywheel 10 movable in the axial direction of the rotating shaft 8. The ball 13 is fitted into the spherical recess, and the flywheel IO is biased to the right in the figure by the spring 14, thereby transmitting rotational force between the flywheel IO and the plate 11. The structure is designed to allow

As mentioned above, when a speed difference occurs between the flywheel IO and the rotating shaft 8, the flywheel IO is pressed by the ball 13, and the lever 15 is pressed against the flywheel IO, and the dump valve 16 is also operated by this lever 15. be done. This dump valve 16 connects a passage 17a communicating with the cylinder chamber (decompression chamber) 17 of the hydraulic pressure modulation section B and a brake fluid discharge passage 19 connected to the reservoir of the master cylinder via piping 18. The valve is provided midway, and is normally closed, blocking the space between the cylinder chamber 17 and the brake fluid discharge path 19, and opens when a speed difference occurs between the flywheel IO and the rotating shaft 8. In this state, the passage 17a and the brake fluid discharge path! 9 is opened, and the brake fluid in the cylinder chamber 17 is led out to the reservoir. When the hydraulic pressure in the cylinder chamber 17 decreases, the balance between the hydraulic pressures above and below the piston 3 is lost, the piston 3 is pushed upward against the biasing force of the spring 3a, and the valve body 2, which had been pushed down by the piston 3, is Hydraulic pressure in valve chamber 1 and spring 2a
The force causes the brake fluid to rise and close the flow path 7a, thereby cutting off the supply of brake fluid to the wheel cylinders.

Further, as the hydraulic pressure in the cylinder chamber 17 decreases due to the opening of the dump valve 16, the internal pressure of the pump chamber 21 connected to the cylinder chamber 17 via the communication passage 20 also decreases, and the introduction chamber 6
The piston 22 in the pump chamber 21a due to the brake fluid pressure of
a rises in FIG. 8, and the piston 22 in the pump chamber 21 is pushed up together with the piston 22a, and the contact 23a is attached to the eccentric cam 23 that rotates together with the rotating shaft 8.
bring it into contact.

At this time, the sole member 22b provided on the outer periphery of the piston 22 is in the state shown in FIG.
And the cylinder room! 7 by a seal member 22b.

At this time, the brake fluid on the brake fluid discharge path 19 side passes through the passage 22c, pushes down the ball valve body 25 as shown in FIG. 8 against the force of the spring 25a, and flows into the pump chamber 21a.

And the rotating shaft 8. Due to the rotation of the eccentric cam 23, the piston 22.22a moves downward in the same figure.

At this time, as the volume of the pump chamber 21a decreases, the hydraulic pressure in the pump chamber 21a increases, and as shown in FIG. street pump room 2
1 to the cylinder chamber 17. As a result, the brake fluid pressure in the cylinder chamber 17 increases. The reciprocating movement of the pistons 22, 22a in this manner produces a pumping action. In this case, if the dump valve 16 is in the open state, the pressure within the cylinder chamber 17 will not increase.

On the other hand, when the circumferential speed of the wheel recovers, the rotational difference between the rotating shaft 8 and the flywheel 10 becomes smaller and they begin to rotate together, and the flywheel 1O returns to its original position. The dump valve 16 is closed, the pressure inside the cylinder chamber 17 is increased by the brake fluid sent from the pump section C, and the valve body 2 is pushed down by the piston 3.
The supply of brake fluid to the wheel brakes is now resumed.

The lever 15 is provided between the flywheel 10 and a stepped cylinder 24 that rotatably supports the rotary shaft 8, and allows the rotary shaft 8 to pass therethrough with a slight gap. The dump valve 1 is operated by the valve operation part 15a.
6 opening/closing operations.

``Problems to be Solved by the Invention'' However, when the conventional skid prevention device as described above is applied as a skid prevention device for a single-channel system for the rear wheels of a part-time four-wheel drive vehicle, the front wheels are If the vehicle is locked, even if the rear wheel brake fluid pressure is reduced, the front and rear axles are directly connected to the drive shaft, so this drive shaft will lock the rear wheels. Therefore, the brake fluid in the rear wheels remains under reduced pressure, and the driver is required to perform braking only with the brakes on the front wheels, resulting in a rapid increase in the force applied to the brake pedal.

Further, if the braking force of the rear wheels further increases or decreases, harmful torsional torque is generated on the drive shaft that directly connects the front and rear wheels, which may cause damage to the drive system.

SUMMARY OF THE INVENTION An object of the present invention is to provide a skid prevention device that solves the problems of six or more conventional skid prevention devices.

"Means for Solving the Problems" The present invention has the following configuration in order to achieve the above object. That is, a detection means for detecting the rotational state of a wheel, an actuator having a pressure reduction chamber and increasing or decreasing brake fluid pressure based on a signal from the detection means, and a pressure fluid connected to the actuator through a passage. In the skid prevention device, the skid prevention device includes a wheel brake that brakes the wheel by receiving the pressure, a reservoir connected to the decompression chamber via a passage, and a master cylinder that supplies pressurized fluid to the actuator via the passage. a valve interposed in the passage between the reservoir and the decompression chamber;
The vehicle is configured to include a valve opening/closing mechanism connected to the valve and closing the valve when the vehicle is in four-wheel drive and opening the valve when the vehicle is in two-wheel drive.

"Function" When applied to a part-time four-wheel drive vehicle, in the four-wheel drive state, the valve opening/closing mechanism closes the valve provided in the passage between the decompression chamber of the actuator and the reservoir, thereby preventing skid. cancel and prevent an increase in brake pedal depression force at this time.

It also prevents an increase in harmful torsional torque acting on the drive shaft when skid prevention is activated during the four-wheel drive state of a part-time four-wheel drive vehicle equipped with a skid prevention device, thereby preventing damage to the drive system. .

Embodiment An embodiment of the skid prevention device of the present invention will be described below with reference to FIGS. 1 to 4. In this embodiment, the same parts as in the conventional example are given the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, the brake system (one channel) of a part-time four-wheel drive vehicle is equipped with one skid prevention device.

The piping 18 provided in the brake fluid discharge path I9 is not directly connected to the reservoir 32 of the master cylinder 31;
A valve 34 is interposed between the brake fluid piping passage 33 and the reservoir 32.

Although it has been described that the reservoir 32 of the master cylinder 31 is connected to the brake fluid discharge path 19, a separate reservoir may be provided inside the device main body 30, which will be described later.

Underwater 35 and 36 in FIG. 1 are front wheel brakes of a four-wheel drive vehicle connected to the master cylinder 31 by a brake fluid pipe 37. 38a is a wheel brake fluid pressure control valve interposed in the brake fluid pipe 38 between the master cylinder 31 and the passage 4 of the skid prevention device main body (actuator) 30. Further, 39 and 40 are wheel brakes connected to the passage 5 of the skid prevention device main body 30 by a brake fluid pipe 41.

The valve 34 is constructed as follows. That is, valve box 4
A stepped through hole 43 is formed in the inside of the holder 2 . Fixing blocks 44 and 45 are fitted and fixed at one end of the through hole 43. A piston 46 is slidably fitted into the other end of the through hole 43 .

A valve chamber 47 is formed within the fixed block 44, and one end of the valve chamber 47 is connected to a communication passage 48 formed in the fixed block 44. A communication path 49 formed in the valve box 42. Said passage 3
3. It communicates with the brake fluid discharge path 19 via a pipe 18. The other end of the valve chamber 47 is connected to the master cylinder 3 via a communication passage 50° formed in the valve box 42 and the passage 33.
1 reservoir 32 .

A valve seat 51 having a through hole formed in the center is provided on the other end side of the fixed block 44 . A valve body 52 is provided in the valve chamber 47 so as to be able to be seated on and removed from a valve seat 51 . Valve body 52
is urged toward the piston 46 by a spring 53 provided within the fixed block 44 and is brought into contact with the piston 46.

The piston 46 is biased toward the side opposite to the valve body 52 by a spring 54 provided between the piston 46 and the valve body 42 . 55, 56.57 are 0 rings. The valve 34 is configured as described above, and the outside of the piston 46 of this valve 34 (
On the right side of the piston 46 shown in FIG.
cam 59 is in contact with it.

The valve opening/closing mechanism 58 consists of a cam 59 rotatably attached to a fixed part, and an operating force transmission mechanism (not shown) such as a wire, link, or solenoid that is connected to the cam 59 and rotates the cam 59. ing.

FIG. 3 is a cross-sectional view showing the state of the valve 34 during four-wheel drive driving, and FIG. 4 is a cross-sectional view showing the state of the valve 34 during two-wheel drive driving.

During two-wheel drive driving, the cam 59 is rotated to the position shown in FIG. 4 by the operating force transmission mechanism. In this state, the piston 46 is moving toward the valve body 52 against the force of the spring 54, and the valve body 52 is separated from the valve seat 51. Therefore, the valve 34 is in the open state, and the piping 1 of the actuator 30
8 communicates with reservoir 32 via valve 34° passage 33.

Therefore, the actuator 30 performs a skid prevention operation.

Further, during four-wheel drive driving, the cam 59 is rotated to the position shown in FIG. 3 by the operating force transmission mechanism.

In this state, the piston 46 is moved toward the cam 59 by the force of the spring 54, and the valve body 52 is seated on the valve seat 51. Therefore, the valve 34 is in a closed state, and the brake fluid discharge path 19 of the actuator 30 is connected to the pipe 18. Valve 349 passage 33. The channel of the reservoir 32 is closed by a valve 34. Therefore, even if the wheels try to lock, the actuator 30 starts operating, and the dump valve 16 opens, the hydraulic pressure in the pressure reduction chamber 17 remains unchanged, and the actuator 30 cannot perform skid prevention operation, and the rear wheel brake 3
On 9.40, hydraulic pressure was generated commensurate with the force applied to the brake pedal, and there was no increase in the force applied to the brake pedal, indicating that skid prevention was activated when a part-time four-wheel drive vehicle equipped with a skid prevention device was in four-wheel drive mode. This prevents an increase in harmful torsional torque acting on the drive shaft in the event of an accident, thereby preventing damage to the drive system.

In the above embodiment, the valve 34 is provided in the middle of the passage 33 between the piping 18 of the actuator 30 and the reservoir 32 of the master cylinder 31. As shown, a valve 61 may be incorporated into the actuator 30 in place of the valve 34 of the above embodiment.

Next, this example will be explained. A stepped through hole 60 communicating with the cylinder chamber 17 is formed in the cylinder 24, and a fixing block 62 fixed to the cylinder 24 is provided on the cylinder chamber 17 side of the through hole 60. The fixed block [1] has a valve seat 6 with a center hole.
3 is fixedly provided. A valve chamber 64 is formed within the fixed block 62, and this valve chamber 64 is connected to the valve seat 63.
The cylinder 24 and the fixed block 62 are communicated with the passage 17a via a passage 17b.

A cylinder 24 is located on the opposite side of the cylinder chamber I7 of the tribute hole 60.
A stopper 66 is provided which is fixed to.

A valve body 67 is provided in the valve chamber 64 so as to be able to be seated on and removed from the valve seat 63. The valve body 67 is biased toward the piston 65 by a spring 68 provided in the fixed block 62, and the valve seat 63 is biased toward the piston 65.
is seated. The piston 65 is pushed against the valve body 6 by a spring 69 provided between the piston 65 and the cylinder 24.
7 and is biased to the opposite side. 70.70a is the 0 ring.

The valve 61 is configured as described above, and the piston 6 of this valve 61
A rod 72 of a valve opening/closing mechanism 71 is in contact with the outside of the valve 5 (above the piston 65 shown in FIG. 5).

The valve opening/closing mechanism 71 is provided between a lever 73 rotatably attached to a fixed part, the rod 72 connected to the lever 73 and inserted through the center hole of the stopper 66, and the stopper 66 and the rod 72. The piston side end of the rod 72 is connected to the piston 6.
5.

FIG. 6 is a cross-sectional view showing the state of the valve 61 during four-wheel drive driving, and FIG. 7 is a cross-sectional view showing the state of the valve 61 during two-wheel drive driving.

During two-wheel drive driving, the lever 73 is rotated to the solid line position shown in FIG. Then, the piston 65 is pushed down toward the valve body 67 via the rod 72 as shown in FIG.
The piston 65 pushes the valve body 67 against the valve seat 6 against the force of the spring 68.
Have them leave their seats from 3.

Therefore, the valve 61 is in an open state, and the cylinder chamber 17 is
It communicates with the dump valve 16 via. Therefore, the actuator 30 performs a skid prevention operation.

Further, during four-wheel drive driving, the lever 73 is rotated to the position shown by the broken line in FIG. Then, the rod 72 is pulled up, the piston 65 moves toward the stopper 66 (upward in FIG. 5) by the force of the spring 69, and the valve body 67 is seated on the valve seat 63 as shown in FIG. Therefore valve 61
is in the open state, and the cylinder chamber 17. Dump valve 16. Brake fluid drain path 19. Piping 18. The path between master cylinder 31 and bar 32 is closed. As a result, the wheels try to lock, and the actuator 30 begins to operate.
Even if the dump valve 16 is opened, the decompression chamber 17 is closed as in the previous embodiment.
The hydraulic pressure remains unchanged, and the actuator 30 cannot perform the skid prevention operation, and the rear brake generates a hydraulic pressure commensurate with the brake pedal depression force, so there is no increase in the brake pedal depression force, and the skid prevention device is installed. To prevent an increase in harmful torsional torque acting on a drive shaft when an anti-skid operation is performed during a four-wheel drive state of a part-time four-wheel drive vehicle, thereby preventing damage to the drive system.

"Effects of the Invention" According to the present invention, there is provided a detection means for detecting the rotational state of a wheel, an actuator having a pressure reduction chamber and increasing or decreasing brake fluid pressure based on a signal from the detection means, and a passage provided in the actuator. a wheel brake that is connected to the actuator and receives pressurized fluid from the actuator to brake the wheels; a reservoir that is connected to the decompression chamber via a passage; and a master cylinder that supplies pressurized fluid to the actuator via the passage. A skid prevention device comprising: a valve interposed in the passageway between the reservoir and the decompression chamber; and a valve connected to the valve that is closed when the vehicle is in four-wheel drive and opened when the vehicle is in two-wheel drive. When applied to a part-time four-wheel drive vehicle equipped with a skid prevention device, the valve opening and closing mechanism is installed in the middle of the path between the decompression chamber of the actuator and the reservoir in the four-wheel drive state. By closing the valve, the skid prevention operation can be canceled, thereby preventing an increase in the brake pedal depression force at this time.

It also prevents an increase in harmful screw torque that acts on the drive shaft when the skid prevention operation is performed during the four-wheel drive state of a part-time four-wheel drive vehicle equipped with a skid prevention device, thereby preventing damage to the drive system. be able to.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention,
Figure 1 is a partially cutaway cross-sectional view with a piping diagram, Figure 2 is a cross-sectional view showing the dump valve, Figure 3 is a cross-sectional view showing the state of the valve during four-wheel drive driving, and Figure 4 is a cross-sectional view showing the state of the valve during four-wheel drive. The figure is a cross-sectional view showing the state of the valve during two-wheel drive driving, and Figures 5 to 7 show other embodiments of the present invention.
The figure is a sectional view showing the state of the valve when running in four-wheel drive, Figure 7 is a sectional view showing the state of the valve when running in two-wheel drive, and Figures 8 to 12 are of the previously applied skid prevention device. Fig. 8 is a partially cutaway sectional view, Fig. 9 is a sectional view showing the dump valve, Fig. 10 is an overall longitudinal sectional view, and Fig. 11 is an enlarged detailed cross-sectional view of the cumulative part of Fig. 8. 12 are enlarged detailed sectional views for explaining the pumping action of the pump section C. A...Lock detection section, B...Liquid pressure modulation section, C pump section, 16...Dump valve, 17...
...Cylinder chamber (decompression chamber), 17a, 33...
...Passage, 19...Brake fluid discharge path, 24.
...... cylinder, 30... skid prevention device main body (actuator), 31 master cylinder, 32
...Reservoir, 34.61 ...Valve, 3
7, 38. 41...Brake fluid piping, 3.9.
40...Rear wheel brake, 58.71.
...Valve opening/closing mechanism.

Claims (1)

[Claims] a detection means for detecting the rotational state of the wheels; an actuator having a decompression chamber and increasing or decreasing brake fluid pressure based on a signal from the detection means; connected to the actuator via a passage and receiving pressurized fluid from the actuator; A skid prevention device comprising: a wheel brake that brakes the wheels with a brake; a reservoir connected to the decompression chamber via a passage; and a master cylinder that supplies pressurized fluid to the actuator via the passage; It is characterized by providing a valve interposed in the passageway between the decompression chamber and a valve opening/closing mechanism connected to the valve to close the valve when the vehicle is in four-wheel drive and open the valve when the vehicle is in two-wheel drive. Skid prevention device.