JPS604017B2 - Deceleration sensing type load responsive braking pressure control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention detects the deceleration of a wheel, considers the working fluid pressure at the time of occurrence of a predetermined deceleration as representative of the load, and seals it, and uses this sealed pressure as the starting point for the operation of a so-called proportional pressure reducing valve. The present invention relates to a deceleration-sensing type load-responsive braking pressure control valve that controls the brake pressure (hereinafter referred to as the "break point").

This type of control valve has a fixed deceleration type and a variable deceleration type, but the fixed deceleration type has a simpler structure and has a better cost/performance ratio. In the fixed deceleration type, the sealing pressure is proportional to the total weight of the vehicle steel (hereinafter referred to as load) during normal operation.

However, the ideal distribution of braking force between the front and rear of a car steel differs greatly between when the car is empty and when the car is loaded, and the change in the turning point of the proportional pressure reducing valve is a change proportional to the load, that is, a change proportional to the sealed pressure. It is preferable to deviate from the origin 0 and have a large slope, like the line B-C in FIG. This is well known to those skilled in the art, and for example, Japanese Patent Publication No. 52-2419
7.

The present invention is intended to realize a deceleration sensing type load responsive braking pressure control valve having the above-mentioned acceleration effect at a low cost and with a high degree of freedom in design.

FIG. 2 shows an embodiment of the present invention.

Rear wheel pressure enters through an input port 1, passes through an inertial valve chamber 2, a valve plunger chamber 3, and is led to an output port 4.

A valve plunger 5, a valve seal 6, and a first spring 7 are housed in the valve plunger chamber 3, forming a proportional pressure reducing valve. The structure of the valve seal 6 is disclosed in Japanese Patent Publication No. 50-9949 and is of a widely used type, so detailed description thereof will be omitted. On the other hand, in the inertia valve chamber 2, there is an inertia ball 9 guided by a cage 8, which moves to the right in the figure when the deceleration of the wheel reaches a predetermined value determined by the installation angle of the control valve.
When they come into contact with each other, the fluid pressure at that time is sealed in the sealing chamber 11. The fill pressure acts on the fill pressure piston 12. A second spring 13 and a third spring 14 are arranged in series between the valve plunger 5 and the sealing pressure piston 12 with an intermediate plate 15 in between.

The second spring 13 is set to be weaker than the third spring 14, so when the filling pressure increases and the filling pressure piston 12 moves to the left, the second spring 13 is compressed first, and the intermediate plate 15 is pressed against the valve plunger 5. When the sealing pressure piston 12 makes contact and tries to move further to the left, the third spring 14
is compressed.

(Strictly speaking, it is a balance between the spring constants of both springs, so even if the second spring is in the process of being compressed, the third spring is also being compressed to some extent.) Furthermore, if the sealing pressure increases significantly, The tip of the sealing pressure piston 12 comes into contact with the valve plunger 5 via the intermediate plate 15.

Now, the area of the part where the valve plunger 5 penetrates the valve plunger chamber 3 is As, and the operating area of the sealing pressure piston is Ac.
shall be.

In addition, the valve plunger 5 moves slightly to the right, and the inner corner of the valve seal 6 comes into contact with the shoulder of the valve plunger 5 to a position where the communication between the valve plunger chamber 3 and the output port 4 is cut off, that is, the valve The force of the first spring 7 when the plunger 5 is in the operating position is F1, and the force when the intermediate plate 15 is pushed by the sealing pressure piston 12 via the third spring 14 and comes into contact with the valve plunger 5 in the upper operating position is F1. Let the force of the second spring be F2.

Further, the force of the third spring 14 when the sealing pressure becomes extremely large and the sealing pressure piston 12 comes into contact with the intermediate plate 15 is defined as F3. Furthermore, the operation start point of the proportional pressure reducing valve, that is, the turning point is Ps.
, if the sealing pressure is Pc, in the initial stage, PsAs=
FIPS=mother...--'1', which corresponds to section D-B in FIG.

When the filling pressure gradually increases and the intermediate plate 15 comes into contact with the valve plunger 5 in its operating position, PsAS=F.
, 1F20PcAc PS=basket (PC-main;)...'21, which corresponds to section B-C in FIG.

Corresponds to the main arch of the virtual confinement pressure pC formula ■ at point A in Figure 1,
The slope corresponds to the area ratio Ac/As.

Also, Akioka at point B is Hatake, the same as in the Kadetsu P side' style.

The abdominal pressure further increases, and the filling pressure piston 12 moves to the intermediate plate 15.
If it comes into close contact with the valve plunger 5 through the valve plunger, the valve plunger will be restricted and will not be able to move to the right.
The passage in the inner corner of the valve seal 6 is no longer closed and no proportional pressure action occurs.

In other words, the breaking point is infinite. The sealing pressure when this depressurizing effect disappears is as follows: PC = pressure, which corresponds to point C' in Figure 1.

Next, the reason for arriving at the configuration of the present invention will be explained. First, the first
The reason why D-B-C is required instead of A-B-C in the diagram is that if A-B-C is the filling pressure Pc = 0, then the corner point P
s=0, that is, the output of the rear wheel system becomes 0. If the inertia valve operates and closes on a steep slope, it is dangerous because no rear wheel output pressure can be obtained even if the braking pressure is subsequently increased.
For this reason, the section D-B in FIG. 1 is necessary in order to guarantee the lowest output in any case. For this reason, the first spring and the second spring must be installed in opposite directions, but in order to find the virtual point A in Figure 1, the formula {2}
In this case, F2>F must be satisfied.

For this reason, the second spring 13 cannot be made to act on the valve plunger 5 at all times, and must be configured so that it starts acting on the valve plunger 5 only when the sealing pressure Pc rises to point B in FIG. be. According to this configuration, when the filling pressure increases successively and reaches point B, the filling pressure piston 12 has already moved a distance sufficient to fill the initial gap between the valve plunger 5 and the intermediate plate 15, so the movement process It is in.

The inertia hole 9 comes into contact with the inertia valve seat 1, and the filling chamber 1
1 from the inertial valve chamber 2, it is extremely difficult to shut off if the filling chamber is rigid at the current filling pressure, but it is easy to shut off if the filling pressure piston is in the process of movement under the current filling pressure. . With a structure in which the filling pressure piston starts to move only at point B (for example, Japanese Patent Publication No. 52-24197), the shutoff performance is poor near point B, i.e., in the air force, and the filling pressure tends to be excessive.However, at point B, the filling pressure piston has already started moving. In the present invention, in which 12 is in the process of movement, there are fewer adverse effects of excessive sealing pressure during air force use. For the requirements up to this point, the third spring 1
4 has no role, and the sealing pressure piston 12 and the intermediate plate 15 may be manufactured integrally, except for the third spring 14.

However, when the valve plunger 5 has a proportional pressure reducing effect, it is necessary to open and close the fluid passage between the inner corner of the valve seal 6 and the shoulder of the valve plunger 5, and the valve plunger 5 has a small 4. Must be able to move distance left and right.

For this reason, it is necessary to provide an elastic connection between the valve plunger 5 and the filling pressure piston 12, or to provide a separate mechanism for providing a damping effect on the filling pressure piston chamber. For example, Tokuko Sho 5
2-37550 is an example in which such a buffer mechanism is provided separately. However, in the present invention, the containment pressure piston 12 and the intermediate plate 15 are separated and a third spring 14 is provided between them to provide a damping effect, thereby eliminating the need for a separate damping piston.

Therefore, the third spring 14 is set to continue functioning up to the necessary upper limit of the proportional pressure reduction action, that is, up to point C in FIG. The arrangement of the second spring 13 and the third spring 14 may be reversed between the inside and the outside, or they may be arranged in the same direction and completely in series. Since the present invention does not rely on a spring constant for functionality, the spring can be easily designed, is suitable for miniaturization, and is also easy to manufacture.

In a structure that requires a large spring constant ratio (for example, Japanese Patent Publication No. 52-24197), the dimensions of the spring with a small spring constant are large, and in actual production, costs are reduced due to constraints on the dividing method of the cliff body, etc. Get high. Also, the manufacturing accuracy of the spring constant is directly connected to the functional accuracy of the control valve. In contrast, the present invention maintains a simple structure and can set the spring constant of each spring arbitrarily (relatively high), so it is small, lightweight, inexpensive, and highly accurate (does not depend on the manufacturing accuracy of the spring constant). ) deceleration sensing type load response control valve can be realized.

[Brief explanation of the drawing]

Figure 1 is a characteristic diagram of the operation start point (break point) of the proportional pressure reducing valve.
FIG. 2 is a sectional view of a deceleration sensing type load responsive braking pressure control valve according to the present invention. 1... Input port, 2... Inertial valve chamber, 3... Valve plunger chamber, 4... Output port, 5... Valve plunger, 6...
Valve seal, 7... First spring, 8... Cage, 9... Inertia ball, 10... Inertia valve seat, 11... Enclosure chamber, 12...
・Enclosed pressure・Piston, 13...Second spring, 14
...Third spring, 15... Intermediate plate, 16... Working fluid flow path. Ozusuke 2

Claims (1)

[Claims] 1. An inertia valve that seals the working fluid pressure at the time of occurrence of a constant deceleration determined by the mounting angle into a containment chamber, a piston that operates according to the sealing pressure of the containment chamber, a pressure reducing valve that reduces the input hydraulic pressure and outputs it, and the above-mentioned A deceleration sensing type load consisting of a spring that transmits the pressing force of the sealed pressure acting on the piston to the pressure reducing valve, and configured to continuously change the pressure reduction starting hydraulic pressure of the pressure reducing valve as the sealed pressure changes. In the responsive braking pressure control valve, an intermediate plate is provided between the pressure reducing valve and the spring, and a second spring acts on the intermediate plate to reduce the pressing force of the spring against the pressure reducing valve. , characterized in that a third spring is provided that creates a gap between the intermediate plate and the pressure reducing valve below a certain sealing pressure and biases the pressure reducing valve in the direction of the intermediate plate independently of the pressing force of the piston. Deceleration-sensing load-responsive braking pressure control valve.