JPS60151163A - Brake hydraulic-pressure equalizer for car - Google Patents

Abstract

PURPOSE:To prevent the generation of a hydraulic-pressure difference between the hydraulic circuits of the both brake apparatuses without increasing the capacity of the both circuits by connecting the both hydraulic circuits through the first and the second always closed valves which are opened by the respective pistons operated by the respective brake hydraulic pressures in two systems. CONSTITUTION:When either of two master cylinders 34 and 36 operates, a piston 18 is operated by the brake hydraulic pressure of a brake hydraulic circuit 37, and the valve piece 14 of an always closed valve is lifted from a valve seat 11b. Since another piston 23 does not operate and the valve piece 15 of another always closed valve is on a valve seat 12b, the brake hydraulic circuits 37 and 38 do not communicate, and brake is applied onto only a left rear wheel. When the both master cylinders 34 and 36 are operated at a same time, the brake hydraulic pressure of the both hydraulic circuits 37 and 38 act onto the pistons 18 and 23, and each piston 18 lifts-up the above-described valve pieces 14 and 15 from the valve seats 11b and 12b against springs 20 and 25. Therefore, the both hydraulic circuits 37 and 38 communicate, and a hydraulic-pressure difference is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention and Industrial Field of Application] The present invention relates to a brake fluid pressure equalizer for a vehicle, and more particularly to a brake fluid pressure equalizer for a vehicle suitable as a brake fluid pressure equalizer for a jJ1 acting l-actor. It is something.

[Prior art]

A plowing tractor is equipped with a brake device for applying a brake to the left rear wheel and a brake device for applying a brake to the right rear wheel. By turning the steering wheel to the left while turning, it is possible to turn with an extremely small turning diameter. On ordinary roads, both brake devices are operated at the same time, but if measures are not taken to equalize the brake fluid pressure of both brake devices, the pedal forces applied to the brake pedals of each brake device may not match. Retract f of the piston of the driven cylinder of each brake device
Due to reasons such as mismatch, a difference occurs in the brake fluid pressure of both brake devices, resulting in a one-sided brake effect.
A problem arose in that the straightness of the vehicle during braking was impaired. Therefore, there is a system in which the brake fluid pressure of both brake devices is applied to both ends, and a balance piston is installed to slide toward the lower pressure side due to the brake fluid pressure difference, in order to suppress the occurrence of the brake fluid pressure difference.

[Problems and Technical Analysis of Prior Art J] However, with the balance piston, it was not possible to reduce the brake fluid pressure difference to zero. Naturally, the balance piston slides toward the low pressure side due to the brake fluid pressure difference, decreasing the volume of the low pressure brake fluid pressure circuit, increasing the brake fluid pressure, and increasing the volume of the high pressure brake fluid pressure circuit. ζThe brake fluid pressure is lowered, but the increase in the volume of the brake fluid pressure circuit increases the invalid stroke of the mask cylinder when only one brake device is operated, and this increase in invalid stroke causes the brake device to operate. Therefore, the amount of increase in the volume of the brake fluid pressure circuit due to the sliding of the balance piston is limited to a range that does not interfere with the operation of only one brake device, and the brake fluid pressure within this range is Increasing and decreasing the circuit volume was not sufficient to reduce the brake fluid pressure difference to zero.

[Technical issues]

Therefore, the technical object of the present invention is to reduce the brake fluid pressure difference to zero without causing a large volume increase in the brake fluid pressure circuit.

[Technical means]

The means taken to solve the above technical problem is that the first brake is operated by the brake fluid pressure of one of the two brake devices.
The brake fluid pressure circuits of both brake devices are connected to each other through a first normally closed valve that is opened by a piston of the other brake and a second normally closed valve that is opened by a second piston that is operated by the other brake fluid pressure. That's true.

[Operation and effects of technical means]

Therefore, when both brake devices are activated, the first
The second normally closed valve is opened by the first and second pistons, respectively, and both brake fluid pressure circuits communicate with each other, so that the brake fluid pressure difference becomes zero. At that time, the volume of each brake fluid pressure circuit increases due to the operation of each piston, but
Since the output and stroke of the piston required to open the normally closed valve are small, there is little increase in the volume of the brake fluid pressure circuit. When only one brake device is activated, the operation of one piston opens one normally closed valve, but since the other normally closed valve is closed, both brake hydraulic circuits remain cut off. In addition, since the increase in the volume of the brake hydraulic circuit due to the operation of the piston is small, one of the brake devices operates without any problems.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings. In the drawings, a first body 1 of a brake fluid pressure equalizer 10 is shown.
1 is provided with a stepped hole 11a.
The stepped cylindrical portion 12 of the second body 12 is located on the right side of a.
a has been inserted. The cylindrical portion 12a is threadedly engaged with the first body 11 at its large diameter portion, and both bodies 11.12 are coupled by this threaded engagement. In the valve chamber 13 formed in the right part of the hole 11a of the first body 11 by the cylindrical part 12a of the second body 12, there are spherical valve bodies 14 and 15 of 2111a, and these are spaced from each other left and right. A spring 16 is disposed to act as if the spring 16
The valve body 14 is connected to the valve seat 1 formed on the first body 11.
1b, and the valve body 15 is seated on a valve seat 12b formed on the second body 12, respectively.

The left opening of the hole 11a of the first body 11 is the connection port 17a.
It is closed by a threaded plug 17 having a stepped piston 18 between the threaded plug 17 and the valve body 14.
is installed. This piston 18 has an internal passage 18a that constantly communicates between the left and right sides of the piston 18.
A spring 20 that pushes the piston 18 to the left is disposed in an annular air chamber 19 on the outer periphery of the small diameter portion of the piston 8 . Air chamber 1
9 communicates with the ■-shaped i@lld on the outer periphery of the first body 11 through the hole 11c of the first body 11, and the ■-shaped groove lid has a groove for preventing external foreign matter from entering the hole 11C. A seal ring 21 is fitted.

The right side 1'' portion of the stepped hole 12C of the second body 12 is closed by a threaded plug 22 having a connection boat 22a, and a stepped piston 23 is disposed between the threaded plug 22 and the valve body 15. is installed. The piston 23 has an internal passage 23a that communicates with the left and right sides of the piston 23, and the air chamber 2
4 is pushed to the right by a spring 25.

The air chamber 24 has a ■ shape a1 due to the hole 12d of the second tenon 12.
2e, and a seal ring 26 similar to the seal ring 21 is fitted into the ■-shaped groove 12e.

In the figure, 27, 28, 29, 30 and 31 are seal rings, 32 and 39 are gaskets, and 40 is a bleeder plug for venting air from the valve chamber 13. 33 is a disc brake that brakes the left rear wheel of the tillage tractor and is operated by brake fluid pressure from the mask cylinder 34. 3
5 is a disc brake for applying brakes to the right rear wheel, and is operated by brake fluid pressure from the mask cylinder 36.

A brake hydraulic pressure circuit 37 extending from the mask cylinder 34 to the disc brake 33 is communicated with the connection port 17a, and a brake hydraulic pressure circuit 38 extending from the mask cylinder 3G to the disc brake 35 is communicated with the connection port 22a.

The brake fluid pressure equalizer 10 having the above structure operates as follows.

When the mask cylinders 34,36 are not activated together, the pistons 18,23 are moved by the springs 20, 23, as shown.
25, the valve bodies 14, 15 are held in abutting position against the inner ends of the plugs 17, 22, and the valve bodies 14, 15 are seated on the valve seats 11b, 12b by springs 16.

When the mask cylinders 34, 36 are actuated together, the brake fluid pressure in the brake fluid pressure circuit 37, 38 reaches the piston 18.
．． 23, the piston 18°23 lifts the valve bodies 14, 15 from the valve seats 1.1b, ], 2b against the springs 20, 25 by the brake fluid pressure, so that the brake 11 is connected to the pressure circuit 37°38. are in communication, and no brake fluid pressure difference occurs.

Either one of the mask cylinders 34, 36, e.g.
is actuated, the piston I8 is actuated by the brake hydraulic pressure of the brake hydraulic pressure circuit 37, and the valve body 14 is moved against the valve seat 11b.
lift from. However, the piston 23 does not operate,
Since the valve seat 15 remains seated on the valve seat 12b, the brake hydraulic pressure circuits 37 and 38 are not communicated, and the brake is applied only to the left rear wheel. When the mask cylinder 36 is actuated,
Although the valve body 15 is lifted from the valve seat 12b by the piston 23, the piston 18 does not operate and the valve body 14 is lifted from the valve seat 12b.
2b, both brake hydraulic pressure circuits 37 and 38 are not communicated with each other, and the brake is applied only to the right rear wheel.

Although the present invention and its embodiments have been described above, the application of the brake fluid pressure equalizer of the present invention is not limited to plowing tractors, and the embodiments are not limited to those illustrated.

[Brief explanation of drawings]

The drawing shows an embodiment of the invention. 10... Brake fluid pressure equalizer, 13.14...
Valve body, 18.23... Piston, 37.38... Brake hydraulic circuit Patent applicant 1 Ishin Seiban Dairyashiki Company Representative Reio Nakai

Claims (1)

[Claims] A first sealing valve that opens the brake fluid pressure circuit of the first brake device and the brake fluid pressure circuit of the second brake device by a first piston operated by the brake fluid pressure of the first brake device; A vehicle brake fluid pressure equalizer connected to a second normally closed valve opened by a second piston operated by the brake fluid pressure of two brake devices.