JPH0418932Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention always supplies the higher air pressure of the left and right rear wheel air springs as a signal pressure to the LSPV.
This invention relates to a vehicle air brake control device.

[Prior Art] Conventionally, as disclosed in Japanese Unexamined Patent Publication No. 52-52078, by supplying air pressure to the rear brakes that is lower than the high pressure of the front brakes in response to changes in rear wheel load. , LSPV (load-sensitive proportional valve) has been proposed to prevent rear wheels from locking due to load transfer during braking.

In conventional air brakes, when the left and right rear wheel air springs are controlled by separate leveling valves, pressurized air at a pressure corresponding to the average air pressure of the left and right air springs, or the air pressure of one air spring is used. Pressurized air at a corresponding pressure must be supplied to the rear brakes. However, in the former case, if the air pressure of both left and right air springs is simply guided to the LSPV,
Since the function of the left and right leveling valves that work separately is impaired, very complicated measures must be taken.
In addition, in the latter case, when driving on rough roads, changes in the load acting on one rear wheel are directly applied to the LSPV as signal pressure, resulting in drastic changes in brake pressure during braking, which impairs smooth braking. There is a problem of being exposed.

[Problems to be solved by the invention] Therefore, the purpose of the invention is to compare the air pressures of the left and right air springs and always guide the higher (or lower) air pressure to the LSPV as the signal pressure. An object of the present invention is to provide a vehicle air brake control device.

[Means for Solving the Problems] In order to achieve the above object, the configuration of the present invention is such that a cylindrical portion is provided on the partition wall of the housing that partitions a pair of air chambers that communicate with the air springs of the left and right rear wheels. and
A spool fitted in a cylindrical part is provided with a pair of annular valve grooves that communicate with each air chamber at all times, and a passage that communicates each valve groove with the valve chamber at the neutral position of the spool. is provided in the partition wall, one end of a lever supported by a shaft in the inner cavity of the partition wall is connected to a spool, the other end projects into the valve chamber, and a poppet valve is provided on both end walls of the valve chamber to close the valve passage by the force of a spring. One of the poppet valves is opened by tilting a lever against the force of a spring.

[Function] When the air pressures of the air springs of the left and right rear wheels are equal, the spool of the control valve is in the neutral position, and the air pressure of both the left and right air chambers is transferred to the valve chamber through the spool's valve groove and the internal passage of the bulkhead. The air pressure in the valve chamber is sent as signal pressure from the outlet to the LSPV (load-sensitive proportional valve) or PRV (proportional relay valve).

If the air pressure in the air spring of one rear wheel is higher than the air pressure of the air spring of the other rear wheel, the spool moves to one side, closing the pair of valve grooves and rotating the lever. A lever opens one poppet valve, and the higher (or lower) air pressure is introduced into the valve chamber through the valve passage and sent to the LSPV from the outlet as signal pressure.

When the brake pedal is pressed, the pressurized air in the air tank is depressurized by the brake valve in accordance with the amount of depression of the brake pedal, and the LSPV corresponds to the air pressure in the valve chamber of the control valve (signal pressure corresponding to the rear wheel load). The pressure is reduced and sent to the left and right rear wheel brake actuators, generating just the right amount of braking force to match the rear wheel load.

[Embodiment of the invention] FIG. 3 shows a schematic configuration of an air brake control device for a vehicle according to the invention. Left and right rear wheels 3
Each of the air springs 33 suspending the air tank 4 is communicated with the air tank 31 via a leveling valve 32. LSPV36 uses the air pressure of the left and right air springs 33 as a signal pressure.
The control valve 35 connects the left and right air springs 33 to
connected between the two, and the higher air pressure is the LSPV
Sent to 36. When the brake is applied, the air tank 31a
The pressurized air passes through the brake valve 40a to the LSPV36.
The pressure is reduced in response to the signal pressure from the control valve 35,
Supplied to the left and right rear wheel brakes.

FIG. 1 is a front sectional view of the control valve 35. A housing is formed by connecting covers 17 to both sides of the main body 7, and a pair of left and right air chambers A are defined by partition walls 7a. The air pressure of the air springs 33 of the left and right rear wheels is introduced into each air chamber A from the inlet 23, respectively. The spool 2 is slidably fitted into the cylindrical portion 21 passing through the partition wall 7a. Return springs 5 are interposed between both end surfaces of the spool 2 and hollow spring seats 8 that are fitted and fixed to both ends of the cylindrical portion 21.
As a result, the spool 2 is urged to the neutral position. A pair of annular valve grooves 22 are provided on the circumferential surface of the spool 2, and each valve groove 22 communicates with each air chamber A through an axial passage 9 on the circumferential surface of the spool 2 and an opening in the spring seat 8. .

In the neutral position of the spool 2, each valve groove 22 is connected to the partition wall 7.
It communicates with a valve chamber B provided inside the partition wall 7a through a pair of passages 3 a. The upper end of the lever 20 is connected to the center portion of the spool 2. The intermediate portion of the lever 20 is located in the inner space of the partition wall 7a and is supported by the partition wall 7a by the support shaft 6, and the lower end of the lever 20 projects into the interior of the valve chamber B.

As shown in FIG. 2, on both end walls 7b of the valve chamber B,
A valve passage 13 is provided which communicates each air chamber A with a valve chamber B, and a poppet valve 4 is supported in the valve passage 13.
The poppet valve 4 is brought into contact with the end of the valve passage 13 by the force of the spring 15, and the stem 4a of the poppet valve 4 is projected so as to come into contact with the lower end of the lever 20. The spring 15 has a spring seat 1 having an opening connected to the end wall 7b.
2 and the poppet valve 4. Lever 2
0 is biased toward the neutral position by a pair of left and right springs 14. Next, the operation of the air brake control device for a vehicle according to the present invention will be explained. When the air pressures of the air springs 33 of the left and right rear wheels are equal, the air pressure of each air spring 33 acts from each air chamber A to each end surface of the spool 2, and the spool 2 is in the neutral position shown in FIG. The air pressure in both the left and right air chambers A is supplied to the valve chamber B via the axial passage 9 of the spool 2, the valve groove 22, and the passage 3, and the air pressure in the valve chamber B is supplied as a signal pressure from the outlet 24 to the LSPV 36 shown in FIG. (or PRV).

The air pressure in the air tank 31a is reduced by the brake valve 40a in accordance with the amount of depression of the brake pedal, and is supplied to a front wheel brake actuator (not shown). At the same time, the air pressure in the air tank 31a is sent to the LSPV 36 via the brake valve 40a, and the control valve 3
The pressure is reduced in accordance with the air pressure in the valve chamber B of No. 5 (signal pressure corresponding to the rear wheel load) and sent to the left and right rear wheel brake actuators.

If a pressure difference occurs between the left and right air springs 33 due to driving on a rough road or a curved road, for example, the air pressure of the air spring 33 of the left rear wheel may be lower than that of the air spring 33 of the right rear wheel.
When the air pressure becomes higher than the air pressure, the spool 2 moves to the right, the left and right valve grooves 22 are closed, and the lever 20
is rotated clockwise around the support shaft 6. Therefore, the left poppet valve 4 is pushed open to the left by the lower end of the lever 20, and the air pressure in the left air chamber A is introduced into the valve chamber B through the valve passage 13, and is sent from the outlet 24 to the LSPV 36.

Conversely, when the air pressure of the air spring 33 of the right rear wheel becomes higher, the spool 2 moves to the left and the lever 2
0 pushes open the poppet valve 4 on the right side, and the air pressure in the air chamber A on the right side is sent to the LSPV 36 via the valve passage 13, valve chamber B, and outlet 24. In this way, the air pressure of the higher air spring 33 among the left and right air springs 33 is always sent to the LSPV 36, and the air pressure is reduced according to the rear wheel load without causing excess or deficiency in braking force. It is supplied to the rear wheel brakes, generating braking force corresponding to the rear wheel load.

In the embodiment described above, one of the left and right poppet valves 4 is pushed open by the lever 20, but in the embodiment shown in FIG. 4, one of the left and right poppet valves 4 is pulled open by the lever 20. The lower air pressure of the left and right air springs 33 is sent to the LSPV or PRV as a signal pressure.

[Effects of the invention] As described above, the present invention includes a cylindrical portion and a valve chamber communicating with the LSPV in the partition wall of the housing that partitions a pair of air chambers that communicate with the air springs of the left and right rear wheels separately. , a pair of annular valve grooves are provided in the spool fitted in the cylindrical portion, which communicate with each air chamber at all times, and a passage is provided in the partition wall to communicate each valve groove with the valve chamber at the neutral position of the spool, and the inner space of the partition wall is One end of the lever supported by the shaft in the section is connected to the spool, and the other end protrudes into the valve chamber,
Poppet valves are installed on both end walls of the valve chamber to close the valve passages by the force of a spring, and one of the poppet valves is opened by tilting a lever against the force of the spring, so that the difference in pressure between the left and right air springs causes The operating spool acts as an actuator, and when the lever is rotated by the actuator, one of the pair of left and right poppet valves is opened, and the air pressure of the higher (or lower) air spring is sent as a signal pressure to the LSPV or PRV. Since the signal pressure is supplied to the LSPV as a signal pressure approximately proportional to the rear wheel load, it is possible to send the signal pressure to the LSPV.

Even if irregular air pressure changes occur in the air springs of the left and right rear wheels due to driving on rough roads, a nearly stable signal pressure can be sent, preventing the rear wheels from locking up, and providing smooth braking action.

The poppet valve operates reliably against vehicle body vibrations, and the signal pressure in the valve chamber controls the LSPV, so the amount of air consumed is small, and by configuring the passage to be elongated, it is possible to control the left and right rear wheels. It does not affect the air pressure of the air spring and does not impair the function of the leveling valves that operate independently on the left and right sides.

[Brief explanation of the drawing]

Fig. 1 is a front cross-sectional view showing the configuration of the air brake control device for a vehicle according to the present invention, Fig. 2 is an enlarged view of the main parts, and Fig. 3 is an overall schematic diagram of the air brake control device for a vehicle according to the present invention. FIG. 4 is a front sectional view showing the main parts of an air brake control device according to a second embodiment of the present invention. A...Air chamber, B...Valve chamber, 2...Spool,
3... Passage, 4... Poppet valve, 5... Return spring, 6... Support shaft, 7... Main body, 7a... Bulkhead, 7
b... end wall, 13... valve passage, 20... lever,
21...Cylindrical part, 22...Valve groove, 23...Inlet,
24... Outlet, 31a... Air tank, 33... Air spring, 34... Rear wheel, 35... Control valve, 36...
LSPV.

Claims (1)

[Scope of utility model registration request] A cylindrical part and
A spool fitted in a cylindrical part is provided with a pair of annular valve grooves that communicate with each air chamber at all times, and a passage that communicates each valve groove with the valve chamber at the neutral position of the spool. is provided in the bulkhead, one end of a lever supported by a shaft in the inner space of the bulkhead is connected to a spool, the other end projects into the valve chamber, and a poppet valve is provided on both end walls of the valve chamber to close the valve passage by the force of a spring. characterized in that one of the poppet valves is opened by tilting a lever against the force of a spring;
Air brake control device for vehicles with air spring suspension mechanisms.