DE3015117A1 - 3/2-WAY SWITCHING VALVE - Google Patents

Description

ε. 6254

March 26, 1980 He / Wl

ROBERT BOSCH GMBH, 7000 Stuttgart 1

3/2-way switching valve

State of the art

The invention is based on a 3/2-way switching valve the genre of the main claim. Such a switching valve * is known (AT-PS 305 809). With such a well-known Switching valve is a special piston that is connected to the valve tappet in order to give the driver a feeling for the to convey effective braking force. This is why such a piston is also called a reaction piston. But he does the switching valve awkward and expensive. It can also leak and fail.

Advantages of the invention

The switching valve with the characterizing features of the main claim In contrast, it has the advantage that no special reaction piston is required for the necessary reaction is. In addition, the valve itself is very simple in construction, it has only a few parts. This makes it less prone to failure and inexpensive. Finally, it is advantageous that the forces in the valve are only balanced out by means of two springs.

130043/0490

In one embodiment, only simple O-rings are used as the valve seal.

drawing

Several exemplary embodiments of the invention are shown in the drawing and are shown in more detail in the following description explained. They show: FIG. 1 a first type of switching valve with O-rings as a seal, FIG. 2 a type with a combined 0-ring metal seal and Figure 3 a design with a special seal.

Description of the exemplary embodiments

The switching valve shown in Figure 1 has a valve housing 1, which is provided with a multiple offset through hole 2. In an upper bore section 3 is a valve tappet 4 guided in a sealed manner. An inner end 5 of the valve tappet 4 protrudes into a storage pressure chamber 6 and there carries a spring plate 7 for a helical compression spring 8. -

An O-ring 10 is embedded in a bore shoulder 9, and a circular disk 11, on which the spring 8 acts from the supply pressure chamber 6, lies on the O-ring 10. That way is. . Between the supply pressure chamber 6 and a pressure change chamber 12, an inlet seat valve 10/11 is formed.

The disk 11 and a helical compression spring 13 acting on the disk from below are located in the pressure change chamber 12, via a connection hole 1 * 1 with a spring-loaded brake cylinder 15 is connected.

- 3 130043/0490

The through hole 2 is on its opposite to the plunger 4 Side closed by a bottom 16, which has a central outlet channel 17 to a relief point l8 has. Inside, the channel 17 ends at a radial surface 19 into which an O-ring 20 is inserted, the diameter of which is smaller is than that of the O-ring 10. In this way, there is a pressure change chamber 12 and the relief point 18 Exhaust valve 11/20 formed.

The switching valve described works as follows: In the drawn center position of the switching valve is the Reservoir pressure has flowed into the spring-loaded brake cylinder 15 via the inlet valve 10/11, which opens like a check valve, has "tensioned the storage spring there and the brake sen solved. The opening of the inlet valve 10/11 can be done by pressing from above on the valve stem 4 while compressing it of the O-ring 20 can be reinforced.

If braking is to take place, the valve tappet is pulled and the disc 11 is relieved of the pressure of the spring 8. Through the Now the predominant force of the spring 13, the O-ring 10 is compressed so much that the disk is separated from the O-ring 20 solves. Now the outlet valve 11/20 is open, and compressed air from the spring-loaded brake cylinder 15 can be via the Relief point 18 to flow off to the outside air.

The pressure applied in each case to the spring-loaded brake cylinder 15 acts via the disk 11 with the effective pressure Surface of the O-ring 10 on the valve tappet 4 back, so that the operator a feeling for the respective braking force receives. In this way, the spring-loaded brake cylinder 15 can be released in stages.

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1300Α3 / 049Ό

κ.

In the figure 2, a switching valve is shown in a housing 21, which also has no special feedback piston. Here two valve seats 22 and 23 are arranged on the same side of an annular disk 24 loaded by a spring 24 ′. The larger of the two seats is an inlet valve seat 22 and is fixed to the housing. The other, the outlet valve seat 23 _S, is provided on a movable valve tappet 25 loaded by a spring 34. A thickening 26 of the valve stem 25 is only used to guide it, it does not carry a seal. The valve tappet 25 acts like a reaction piston, with the area inside the valve seat 23 in the event of a pressure drop. When the pressure rises, this area is part of the total reaction area.

An O-ring 27 is arranged within the inlet valve seat 22, which is pressed by an annular wave spring 28 against the washer 24 and that of an annular one Housing extension 29 is worn.

Underneath the washer 24 there is one for connecting the spring-loaded brake cylinder certain Druckwechselkanuner 30, an O-ring 27 receiving annular space 31 is one on one Supply line connected storage pressure chamber and an outside air chamber 32 surrounds the lower end of the valve stem 25 and is connected to a relief point 33.

In the position shown, the spring-loaded brake cylinder is vented and the brakes are applied. To solve the The brake is applied, the valve tappet 25 is moved into the valve housing 21, the outlet valve 23/24 is closed and the inlet valve 22/24 is opened. The O-ring 27 ensures that the supply pressure does not flow off to the outside air.

1300A3 / 0A9O

R. 6 2 A-

The reaction of the respective effective braking force is determined by the spring 2V and by the service diameter of the O-ring 27 on the annular disk 2k when the pressure rises, and when the pressure drops only by the sealing diameter of the valve seat 23.

FIG. 3 shows a housing 35 of a switching valve which is largely similar to that according to FIG. The same parts therefore also have the same reference numbers. Only here a closing body annular disk J> 6 has a small sealing lip extension 37 which protrudes from the inside into the housing extension 29 and seals there.

The mode of operation is just as in Figure 2.

130043/0490

Claims (2)

R. 6254 March 26, 1980 He / Wl ROBERT BOSCH GMBH, 7000 Stuttgart 1 Expectations 3/2-way switching valve for compressed air braking systems with one guided in a valve housing, movable from the outside, and subject to a reaction of the applied pressure Valve tappet and also with two valve seats arranged in the housing, which when the valve is switched from a double seat closing body alternately covered or released or both in a central position of the valve are covered, characterized in that a disc (11, 24, 36) is used as the closing body, which on each both sides of the variable force of a spring (8, 13; 24 ', 26; 24', 35) is exposed and that the two Springs form the sole support of the closing body with respect to the housing (1, 21, 35) and the valve stem (4, 26). 2. Switching valve according to claim 1, characterized in that the two valve seats are formed by two O-rings (10, 20) with different diameters, of which the larger one (10) on the side of a storage pressure chamber (6) and the smaller (20) on the side of a relief point (18) .is. 130043/0490 " ² " - ₂ - row δ 2 54 _S in 3 x switching valve according to claim 1 or 2, characterized in that the disc (11) and relative to the housing (1) supported spring (13) are arranged in a chamber (12) to which a spring-loaded brake cylinder (15) is connected. 130043/0490