JP2520953Y2 - Brake fluid pressure control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a hydraulic control device for a two-wheel drive vehicle,
In particular, the present invention relates to a technique effectively applied to a brake fluid pressure control device having both an antilock mechanism for preventing wheel lock during vehicle braking and a traction slip control mechanism during vehicle start.

[Conventional technology]

As a brake fluid pressure control device having both an anti-lock mechanism and a traction slip prevention mechanism of this type, the one shown in FIG. 3 is known.

In the figure, the first master pipes 3a, 3a from the master cylinder 8 connected to the brake pedal 6 to the wheel cylinders 1a, 1a on the drive wheel side, and the wheel cylinders 1b, 1b on the driven wheel side,
It has a second master pipe 3b, 3b leading to 1b, and hold valves 10a, 10a, 10b, 1 on both master pipes 3a, 3a, 3b, 3b.
0b is installed. Also, each wheel cylinder 1a, 1a, 1
Decay piping 12a, 12a, 12b, 12 from b, 1b to the reservoir 7
Decay valves 13a, 13a, 13b, 13b are provided on b.

A cut valve 14 is provided on the first master pipe 3a before branching, and a non-return valve having a forward direction from the wheel cylinder side to the master cylinder side is provided on a bypass liquid passage bypassing the cut valve 14. The valve 15 is interposed.

In this prior art, the hydraulic pressure source 4 is composed of first and second pumps 4a, 4b operated by a motor M, and the first pump 4a is connected to the first master pipes 3a, 3a to drive wheels. Brake fluid is supplied to the wheel cylinders 1a, 1a on the side, and the second pump 4b is connected to the second master pipes 3b, 3b so as to supply brake fluid to the wheel cylinders 1b, 1b on the driven wheel side. .

The case where anti-lock control and traction slip control are performed by using the brake fluid pressure control device shown in FIG. 3 will be briefly described as follows.

That is, when re-pressurizing the wheel cylinders 1a, 1a, 1b, 1b during anti-lock control during vehicle braking, independent control is required for each wheel, so all wheel cylinders 1a, 1a, It is necessary to supply brake fluid for 1b and 1b. In this case, brake fluid is supplied from the first pump 4a to the wheel cylinders 1a, 1a on the drive wheel side, and from the second pump 4b to the wheel cylinders 1b, 1b on the driven wheel side.

On the other hand, when performing traction slip control during vehicle start + rapid acceleration, the brake fluid may be supplied only to the wheel cylinders 1a, 1a on the drive wheel side.

In this case, the second pump used for the driven wheels
It was necessary to stop the operation of 4b or shut off the supply path.

[Problems to be solved by the device]

However, in the brake fluid pressure control device in the above-mentioned prior art, the wheel cylinders 1 of the first and second pumps 4a and 4b are not used.
It was pointed out by the present inventor that the capacity of both pumps 4a, 4b could not be fully utilized because the distribution of brake fluid supply to a, 1a, 1b, 1b was fixed.

That is, during the traction slip control, the second
Since the pump 4b was not used at all, the control efficiency was not always good.

An object of the present invention is to make the hydraulic pressure source function effectively and improve the control efficiency by switching the hydraulic pressure supply system from the hydraulic pressure source according to the control mode.

[Means for solving the problem]

The present invention relates to a drive wheel side wheel cylinder first pump that acts as an auxiliary hydraulic pressure source during antilock control, and
In a brake fluid pressure control device including a driven wheel side wheel cylinder second pump, a switching valve for connecting the second pump to the driving wheel side wheel cylinder is provided at the time of traction control, and the switching valve is a master cylinder. The brake fluid pressure control device is characterized in that it is a fluid pressure operated valve that is switched by pressure.

[Action]

According to the above-mentioned means, by switching the hydraulic pressure supply path by the switching valve, the first pressure is applied when the anti-lock control is repressurized.
The brake fluid is supplied to each wheel cylinder that is originally shared by the pump and the second pump, and during the traction slip control, the second pump is connected to the wheel cylinder on the driving wheel side by controlling the switching valve, The brake fluid is concentratedly supplied to the wheel cylinders on the drive wheel side.

As a result, the auxiliary hydraulic pressure source can be effectively operated even during traction slip control, and the brake hydraulic pressure control efficiency can be improved.

〔Example〕

FIG. 1 is a hydraulic pressure path diagram showing a brake hydraulic pressure control device according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view showing a switching valve.

In the figure, this device has a tandem type master cylinder 8 connected to a brake pedal 6 as a hydraulic pressure supply passage 3.
Starting from one hydraulic pressure generation chamber 8a, branched in the middle and connected to the left and right drive wheel wheel cylinders 1a, 1a, respectively, first master pipes 3a, 3a, and the other hydraulic pressure generation chamber 8b of the master cylinder 8 It has the second master pipes 3b, 3b which are branched off in the middle of departure and connected to the wheel cylinders 1b, 1b of the left and right driven wheels, respectively.

Then, hold valves 10a, 10a composed of normally open solenoid valves are respectively provided on the first master pipes 3a, 3a, and by closing the hold valves 10a, 10a,
The pressure inside the wheel cylinders 1a, 1a can be maintained in a predetermined state. Further, decay pipes 12a, 12a are laid between the wheel cylinders 1a, 1a of the drive wheels and the reservoir 7 of the master cylinder 8, and the decay pipes 12a, 1a are provided.
On top of 2a, a decay valve 13a composed of a normally closed solenoid valve,
13a are respectively interposed, and when they are opened, the hydraulic pressure in the wheel cylinders 1a, 1a of each drive wheel is reduced.

With the same configuration, hold valves 10b and 10b are respectively provided on the second master pipes 3b and 3b, and the wheel cylinders 2
Decay pipes 12b and 12b are laid between b and 2b and the reservoir 7, and decay valves 13b and 13b are provided in the decay pipes 12b and 12b.
Are installed respectively.

A cut valve 14 composed of a normally open solenoid valve is provided in the first master pipe 3a before branching, and
A bypass path that bypasses the cut valve is provided, and a check valve 15 whose forward direction is from the wheel cylinder side to the master cylinder side is provided on the bypass path.

On the other hand, a hydraulic pressure source 4 for pressurizing the brake fluid drawn from the reservoir 7 of the master cylinder 8 is connected to the first master pipe 3a, and a first sub-pipe 9a is connected to the second master pipe 3b. The second sub-pipe 9b is provided.

Here, the hydraulic pressure source 4 comprises a first pump 4a and a second pump 4b driven by one motor M, and the first pump 4a
Is connected to the first sub pipe 9a, and the second pump 4b is connected to the second sub pipe 9b.

A characteristic point of this embodiment is that a switching valve 5 is connected to the second sub pipe 9b from the second pump 4b. The output side of the switching valve 5 is divided into two systems, one of which is directly connected to the second master pipe 3b on the driven wheel side as the second sub pipe 9b, and the other is connected to the first sub pipe 9a by the connecting pipe 3d. ing.

By controlling the switching valve 5, the brake fluid from the second pump 4b can be selectively supplied to the wheel cylinders 1a, 1a on the driving wheel side or the wheel cylinders 1a, 1b on the driven wheel side. .

The structure and function of the switching valve 5 will be described in more detail with reference to FIG.

As shown in the figure, the inside of the switching valve 5 has a smaller diameter, a larger diameter, and a smaller diameter in the first, second, and third cylinder chambers from the right direction in the figure.
It has S ₁ , S ₂ , and S ₃ , and these three cylinder chambers S ₁ ,
A rod R penetrating S ₂ and S ₃ is internally provided so as to be slidable in the axial direction. The rod R in the axial end surfaces and in the vicinity of the center of the piston seal rings 16a to P, 16b, 16c are fitted, seals between the cylinder chambers _{S 1, S 2, S 3} .

In the first cylinder chamber S ₁ , a ball valve V ₁ biased by a spring Sp ₁ in the direction of the second cylinder chamber S ₂ is arranged, and in the third cylinder chamber S ₃ , a spring valve V ₁ is also provided.
A ball valve V ₂ is arranged which is biased by Sp ₃ in the direction of the second cylinder chamber S ₂ . The ball valves V ₁ and V ₃ in the first and third cylinder chambers S ₁ and S ₃ are brought into contact with the ends of the ball valves V ₁ and V _{3 as} the rod R moves, and resist the biasing force of the springs Sp ₁ and Sp ₃ . In this structure, the first or third cylinder chamber S ₁ , S ₃ is opened / closed.

The rod R is integrally formed with a piston portion P having the maximum diameter in the second cylinder chamber S ₂ , and the piston portion P is normally formed by a spring Sp _{2 so} that
Is urged in the cylinder chamber S ₁ direction and the end surface of the piston portion P abuts on one end surface of the second cylinder chamber S ₂ ,
The first cylinder chamber S ₁ and the second cylinder chamber S ₂ are closed.

As described above, the switching valve 5, the brake fluid from the second pump 4b third through the cylinder chamber S ₃ of the driven wheel side wheel cylinder 1b, or tell 1b, or the first cylinder chamber S
_It has a function of selecting whether to transmit to the wheel cylinders 1a, 1a on the drive wheel side through ₁ . In the state shown in FIG. 2, the first cylinder chamber S ₁ is in an open state, and the second pump
Brake fluid from 4b is wheel cylinders 1a, 1a on the drive wheel side.
It is in a state that can be transmitted to.

Next, switching control by the switching valve 5 will be described.

First, the traction slip control at the time of starting or sudden acceleration of the vehicle is performed to prevent the drive wheels from slipping, and first, the cut valve 14 is closed to prevent the brake fluid from returning to the reservoir 7. Further, by driving the motor M, the brake fluid is supplied from the first pump 4a to the wheel cylinders 1a, 1a via the first sub pipe 9a and the master pipe 3a.

On the other hand, at this time, the switching valve 5 is in the state shown in FIG. In this state, the piston P is a spring
The sp ₂ is biased to the first cylinder chamber S ₁ direction, a state in which the first cylinder chamber S ₁ presses the ball valve V ₁ of the first cylinder chamber S ₁ is opened, the 2 pumps
Supply pipe 3e from 4b and drive wheel side wheel cylinders 1a, 1a
To the connecting pipe 3d.

The urging force of the spring Sp _{2 at} this time needs to be determined in consideration of the hydraulic pressure from the second pump 4b and the hydraulic pressure required for the wheel cylinders 1a, 1a on the drive wheel side. .

Thus, during traction slip control,
Since the brake fluid from the first pump 4a and the second pump 4b is centrally supplied to the wheel cylinders 1a, 1a on the drive wheel side through the first sub-pipe 9a, only one pump of the prior art is driven. It is possible to obtain a control efficiency that is almost twice as high as that obtained by supplying the brake fluid.

Next, the operation of the switching valve 5 during antilock control will be described.

At the time of anti-lock control, each wheel is controlled independently, but if there is a risk that each wheel will be locked due to, for example, a lock signal, the hold valves 10a, 10a, 10b, 10b are closed. By controlling the decay valves 13a, 13a, 13b, 13b, decompression control of the wheel cylinders 1a, 1a, 1b, 1b is performed.

Next, when the wheel cylinders 1a, 1a, 1b, 1b need to be repressurized, the hold valves 10a, 10a, 10b, 10b are opened and the brake fluid is supplied from the hydraulic pressure source 4 to the first and second sub pipes. 9a, 9
It is supplied to each wheel cylinder 1a, 1a, 1b, 1b through b.

The switching valve 5 in the repressurized state operates as follows.

First, since the brake pedal 6 is stepped on during the antilock control, the hydraulic pressure from the master cylinder 8 is transmitted to the _second cylinder chamber S ₂ through the second master pipe 3b before branching. This allows the second cylinder chamber
When S ₂ is pressurized, pressure is applied to the large area portion A _L of the piston portion P, and the piston portion P is moved in the _third cylinder chamber S ₃ direction against the biasing force of the spring Sp ₂ . The third cylinder chamber of the rod R is interlocked with the movement of the piston P.
End of the S ₃ is the third cylinder chamber S ₃ presses the ball valve V ₂ is opened. As a result, the brake fluid from the second pump 4b is supplied to the wheel cylinders 1b, 1b on the driven wheel side via the third cylinder chamber S ₃ and the second sub pipe 9b. In this way, during the antilock control, the brake fluid from the second pump 4b is transmitted to the wheel cylinders 1b, 1b on the driven wheel side, which are originally shared by the second pump 4b.

[Effect of device]

According to the present invention, the auxiliary hydraulic pressure source can be effectively operated even during traction slip control, and the brake hydraulic pressure control efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a hydraulic pressure path diagram showing a brake hydraulic pressure control device according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view showing a switching valve,
FIG. 3 is a hydraulic pressure path diagram showing a brake hydraulic pressure control device in the prior art. 1a, 1a, 1b, 1b …… Wheel cylinder (W / C), 3 …… hydraulic pressure supply path, 3a …… First master piping, 3b …… Second master piping,
3d …… Connection piping, 3e …… Supply piping, 4 …… Decompression source, 4a…
… First pump, 4b …… Second pump, 5 …… Switching valve, 6 ...
... Brake pedal, 7 ... Reservoir, 8 ... Master cylinder (M / C) 9a ... First sub-pipe, 9b ... Second sub-pipe, 10a, 10b ...
… Hold valves, 12a, 12b …… Decay piping, 13a, 13b
...... Decay valve, 14 ...... Cut valve, 15 ...... Check valve, 16a, 16b, 16c ...... Seal ring, M ...... Motor, P
...... Piston, R ...... Rod, S _{1 to} S ₃ ...... Cylinder chamber, Sp _{1 to} Sp ₃ ...... Spring, V _{1 to} V ₃ ...... Ball valve.

Claims (1)

(57) [Scope of utility model registration request] 1. A first pump for driving wheel side wheel cylinders, each pump acting as an auxiliary hydraulic pressure source during antilock control,
In a brake fluid pressure control device including a second wheel wheel wheel cylinder pump, a switching valve for connecting the second pump to the driving wheel side wheel cylinder is provided at the time of traction control, and the switching valve is a master cylinder. A brake fluid pressure control device, which is a fluid pressure operated valve that is switched according to pressure.