JPS645640Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a brake hydraulic control device used in a hydraulic control mechanism of an automobile, and particularly relates to a hydraulic control device installed in a hydraulic oil pipe of a rear wheel braking system.

In the general structure of a vehicle hydraulic braking mechanism, as shown in FIG. It is transmitted to each wheel cylinder 5, 6 of the front wheel and rear wheel through each hydraulic oil pipe 3, 4a, 4b of the wheel system, respectively,
Each wheel is braked.

By the way, if the hydraulic pressure from the master cylinder 2 were transmitted to the front and rear wheels in exactly the same way, the rear wheels would lock earlier due to the deceleration that occurs when the vehicle moves, causing what is called a A tail wobbling phenomenon is likely to occur, and in that case, there is a possibility that the running of the vehicle may be endangered.

For the purpose of preventing such a danger, it is generally done to make the braking force of the rear wheels weaker than the braking force of the front wheels.As a means of doing so, between the hydraulic oil pipes 4a and 4b of the rear wheel braking system, A method is adopted in which a hydraulic control device 7 is installed to reduce the operating pressure applied to the wheel cylinder 6 of the rear wheel to an appropriate value.

Here, an outline of a conventionally known brake hydraulic control system that switches the distribution of braking force between front wheels and rear wheels at a predetermined deceleration or higher will be explained with reference to FIG.

This device 7 has an appropriate forward elevation angle θ with respect to the horizontal line.
The device 7 includes:
A hydraulic input passage 8 and a hydraulic output passage 9 are provided and connected to the pipes 4a and 4b, respectively.

Therefore, an opening/closing passage 10 and an adjustment chamber 11 having the following structure are provided in parallel between the two passages 8 and 9.

(a) Deceleration-sensitive opening/closing passage 10 This passage 10 is along the direction of the elevation angle θ, and the openings 10a and 10b at both ends communicate with the input passage 8 and the output passage 9, respectively. A seal 12 is fitted into the side opening 10b.

A ball valve 13 as an inertial mass is accommodated in the opening/closing passage 10, and a seal 12 is housed inside the opening/closing passage 10.
In other words, under normal conditions, the opening 10b is opened and the opening/closing passage 1 is operated.
0, and closes the passage 10 when a deceleration greater than the deceleration (forward acceleration) corresponding to the elevation angle θ is applied.

(b) Adjustment chamber 11 This chamber 11 is formed by communicating an atmospheric chamber in the center, a narrow-diameter chamber that opens to the input passage 8, and a large-diameter chamber that opens to the output passage 9.
A piston 14 is inserted into the interior of the piston 1 .

The piston 14 is a sliding body in which a small-diameter piston 14a and a large-diameter piston 14b are formed on both sides of an intermediate shaft, and each piston 14a, 14b is connected to a small-diameter chamber and a large-diameter chamber through a seal. inserted into the chamber.

In addition, a compression spring 16 is interposed between the end face of the atmospheric chamber and the spring receiver 15, and the bias of the spring 16 causes the piston 14 to move into the output passage 9.
Pressed to the side.

Here, we will discuss the operation of the conventional hydraulic control device configured as described above. Below, we will explain the input oil pressure, that is, the pressure generated in the master cylinder, Pm, and the output side, that is, the operating pressure transmitted to the wheel cylinders.
Call it Pr.

(a) Normal state In the normal state (as shown) in which the opening/closing passage 10 is open, Pr=Pm, that is, the operating pressures of the front and rear wheel systems are equivalent, regardless of the operation of the piston 14.

(b) When deceleration is sensed In a braking state where a deceleration greater than the limit deceleration (referred to as Gr) for climbing a slope with an elevation angle θ is sensed, the input side of the output passage 9 is blocked, and The internal pressure Pr is the piston 14 described below.
It is adjusted and controlled by the equilibrium operation of.

Now, calculate the diameter of the small diameter chamber and the diameter of the large diameter chamber, respectively.
When D ₁ and D ₂ and the elasticity of the spring 16 is F, the sliding balance of the piston 14 is expressed as PrD ₂ =PmD ₁ +F, so the operating pressure Pr is Pr=D ₁ /D ₂ Pm + F/D ₂ ... (graph shown in Figure 3).

As a result, the braking force distribution to the rear wheels is switched, and the braking force of the rear wheels is suppressed to be lower than the braking force of the front wheels, thereby preventing early locking of the rear wheels.

Note that the greater the weight of the vehicle, the higher the pressure Pm generated when the critical deceleration Gr occurs, and therefore, the pressure reduction switching control transition point is delayed (or (earlier), which always results in a suitable braking action.

However, in the conventional device, the adjustment chamber 11
An opening/closing passage 10 comprising a piston 14 and a ball valve 13
Because the two were placed in separate spaces, the equipment became complicated and large, resulting in high costs.

This invention was made with attention to the above circumstances,
The purpose of this is to provide a flow path in the main body of the device, a piston in this flow path, an opening/closing path in the piston, and a ball valve in this opening/closing path to simplify the structure and reduce the size. The present invention aims to provide a brake hydraulic pressure control device that can perform the following functions.

Hereinafter, the present invention will be explained based on an illustrated embodiment. Reference numeral 21 in FIG. 4 is a device main body having an appropriate elevation angle θ with respect to the horizontal line.A hydraulic input port 22 is provided on the upper surface of the device main body 21, and a hydraulic pressure output port 23 is provided on one side of the main body 21. It is provided. The hydraulic oil piping 4a on the master cylinder side is connected to the hydraulic input port 22, and the hydraulic oil output port 23
A hydraulic oil pipe 4b on the wheel cylinder side is connected to. Further, a flow path 24 is provided in the device main body 21 to communicate the hydraulic pressure input port 22 and the hydraulic output port 23, and a piston 25 is slidably provided in the flow path 24 along the longitudinal direction thereof. It is stored. An opening/closing path 26 is provided inside the piston 25 along its longitudinal direction, and this opening/closing path 26 communicates with the hydraulic output port 23 via a communication path 27 . A ball valve 28 is rotatably housed within the opening/closing path 26. A sealing material 29 is attached to the outlet of the opening/closing path 26, and the opening/closing path 26 is opened or closed by the ball valve 28 coming into contact with or separating from this sealing material 29. Further, a port 30 is provided on a part of the peripheral wall of the piston 25.
is bored, and the opening/closing path 26 is communicated with the flow path 24 through this port 30.

On the other hand, first and second flanges 31 and 32 are provided at a predetermined interval on the outer circumferential wall of one end of the piston 25.
are provided protrudingly, and these first and second collar portions 31,
A sealing material 33 is interposed between 32 and integrally protrudes from the inner circumferential wall surface of the main body 21. The second flange 32 is biased by a spring 34, which pushes the piston 25 toward the right side in the figure, causing the lower end of the piston 25 to contact the opening edge of the hydraulic output port 23. It is stopped in close contact.

The other end of the piston 25 is inserted into a plug 35 that opens and closes the opening of the main body 21, and the end of the spring 34 comes into contact with the insertion side end surface of the plug 35 via a retainer 36. has been done. A stopper 37 is screwed into the end of the piston 25, and the ball valve 28 is brought into contact with the stopper 37 to be stopped. Note that 38, 39, and 40 are seal members.

Next, the operation of the above embodiment will be explained.

First, when operating the brakes, the ball valve 28 is activated during braking before the deceleration of the vehicle reaches the limit deceleration Gr.
is decreasing as shown by the solid line, so the hydraulic pressure entering from the hydraulic input port 22 is flowing through the flow passage 24 and the opening/closing passage 26.
and is added to the wheel cylinder from the hydraulic output port 23 via the communication path 27.

In this state, the input generated pressure Pm is output as is, so the operating pressure Pr is equal to the generated pressure Pm, that is, Pr=Pm.

Next, when the pressure Pm generated during deceleration running is Pg,
When Gr is reached, the ball valve 28 climbs up the slope and closes the communication passage 27 as shown by the broken line. At this time,
The force pushing the piston 25 to the left is A×Pr,
The force pushing to the right is (C-B ₁ )×Pm+F. (Here, A indicates the pressure receiving area on the output port 23 side of the piston 25, C-B ₁ indicates the pressure receiving area on the input port 22 side,
F indicates the biasing force of the spring 34. ) In other words, the relationship is A×Pr=(C-B ₁ )×Pm+F, and when this equilibrium condition is graphed, the sixth
The result will be as shown in the figure.

Furthermore, assuming that the deceleration at which the ball valve 28 rolls is constant, the heavier the vehicle is, the greater the hydraulic pressure must be generated. When the oil pressure at which the ball valve 28 rolls during normal loading is designated as Y, the graph is summarized as shown in FIG. 7.

As is clear from FIG. 7, a wheel cylinder pressure Pr higher than the equilibrium condition C-B ₁ /A×Pm+F/A is generated at the above-mentioned points X and Y, so that the communication passage 27 is blocked. However, in this state Pr
= Pm, so the force pushing to the left is A x Pr, and unless Pm increases further, the balance with the force to the right cannot be maintained, and even if Pm increases, Pr does not increase at all, which continues. be done.

Then, as shown in Figure 8, the balance is restored at point Z, and the relationship between Pr and Pm is Pr x A = Pm
×(C-B ₁ )+F, and the braking force distributed to the rear wheel system is reduced to prevent locking, similar to the conventional braking hydraulic control system. That is, the ball valve 28 remains blocking the communication passage 27, but the output port 23 side of the piston 25 and the input port 22 side are closed.
The operating pressure Pr is automatically adjusted based on the difference in pressure receiving area between the two sides and the biasing force of the spring 34. Specifically, the pressure receiving area A on the output port 23 side is
Since the pressure receiving area C-B ₁ on the side is larger, the piston 25 is displaced and the first flange 31 touches the sealing material 3.
3, the working pressure Pr is no longer influenced by the generated pressure Pm. However, the generated pressure Pm
increases, and the biasing force of the spring 34 acts, so the piston 25 is displaced in the opposite direction and the first flange 31 is separated from the sealing material 33. Then, the hydraulic oil led to the flow passage 24 is transferred to the second
It is led out to the wheel cylinder of the rear wheel through the output port 23 between the first flange 32 and the sealing material 33 and between the first flange 31 and the sealing material 33. When the working pressure Pr increases again to a certain extent, the piston 25 is displaced again, and this action is repeated on the outer circumference of the piston 25. Therefore, the braking force on the rear wheels is reduced and locking is prevented.

As mentioned above, since the piston 25 is provided with the on-off path 26 and the ball valve 28 is provided within this on-off path 26, the structure is simplified compared to the case where the piston 25 and the on-off path 26 are provided in separate spaces. , miniaturization becomes possible.

In addition, the master cylinder pressure Pm that is sensitive to deceleration
Even if the master cylinder pressure changes after deceleration
Since the increase in wheel cylinder Pr can be kept relatively small with respect to the increase in Pm, the hydraulic characteristics are particularly suitable for vehicles with a high vehicle height and short wheelbase (vehicles with a small slope of the ideal braking force distribution line). There are advantages that can be obtained.

As explained above, the present invention provides a flow path in the main body of the device, a piston in this flow path, an opening/closing path in this piston, a ball valve in this opening/closing path, and a spring that biases the piston. The piston receives a force in the direction of opening the flow passage due to the hydraulic pressure on the input port side, and a force in the direction of closing the flow passage due to the hydraulic pressure on the outlet side, and opens and closes the flow passage on the outer circumferential side. At the same time, the pressure receiving area on the output port side is set to be larger than the pressure receiving area of the hydraulic pressure on the input port side, the above-mentioned opening/closing path communicates the input port side and the output port side, and the above-mentioned ball valve The opening/closing path is closed by the speed, and the spring urges the piston in the direction to open the flow path, so hydraulic characteristics suitable for vehicles with a small slope of the ideal braking force distribution line can be obtained, and at the same time, it is possible to Compared to such a system in which the piston and the opening/closing path are arranged in separate spaces, the structure can be simplified, the size can be reduced, and the cost can be reduced.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing a general hydraulic oil system in a vehicle braking system, Fig. 2 is a sectional view showing a conventional brake hydraulic pressure control device, and Fig. 3 is a graph showing the operating pressure characteristics of the device. FIG. 4 is a sectional view showing a brake hydraulic control device which is an embodiment of the present invention, FIG. 5 is a sectional view showing a part of the piston of the device, and FIG. FIG. 7 is a graph showing the characteristics under piston equilibrium conditions and under deceleration braking below Gr, and FIG. 8 is a graph showing the operating pressure characteristics of the same device. 21...Device main body, 22...Hydraulic pressure input port, 23
...Hydraulic output port, 24...Flow path, 25...Piston, 26...Opening/closing path, 28...Ball valve, 34...
spring.

Claims (1)

[Scope of utility model registration request] In a device installed in the hydraulic oil piping of an automobile rear wheel braking system, a device main body, a hydraulic input port and a hydraulic output port provided in the device main body, and a flow system that communicates these hydraulic pressure input ports and hydraulic pressure output ports. The force in the direction of opening the above-mentioned flow path by the hydraulic pressure on the input port side,
In addition, it is provided in the flow passage so that the flow passage is opened and closed on the outer circumferential side by receiving a force in the direction of closing the flow passage due to the hydraulic pressure on the output port side, and the pressure receiving area of the oil pressure on the output port side is larger than the pressure receiving area of the hydraulic pressure on the input port side. A piston installed to have a large pressure receiving area, an opening/closing path provided in this piston and communicating with the input port side and the output port side of the flow path, and a switching path provided in this opening/closing path that is sensitive to deceleration. A braking hydraulic control device comprising: a ball valve that operates to close an opening/closing path at a deceleration of a predetermined value or more; and a spring provided to bias the piston in a direction to open the flow path.