JPS61150860A - Control valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The invention relates to control valves.

Heavy goods transport vehicles are usually equipped with air brake systems. These air brake systems generally include spring-applied, fluid-pressure-released parking and emergency brakes (hereinafter referred to as spring brakes) controlled by control valves mounted on the vehicle's dashboard. A typical control valve of this type is disclosed in US Reissue Patent No. RE 25,969. This type of control valve automatically moves to a position that releases the release pressure communicated to the spring brake when the pressure in the brake system drops below a predetermined level, or it automatically moves to a position that releases the release pressure that is communicated to the spring brake when the vehicle is parked and the spring brake It is designed to be activated manually when the system is activated.

Since the pressure within the control valve changes rapidly from a high pressure level to a low pressure level when the control valve is actuated, the sealing mechanism installed in this type of conventional control valve is quite complex and expensive. It has become a thing.

These conventional control valves use valve actuating plungers that are rapidly switched from a high-pressure environment to a low-pressure environment, so high pressure that enters the seal cavity deforms the seal when the pressure drops. This could force the seal out of the cavity and result in the control valve becoming inoperable.

The present invention solves the above-mentioned problems and provides a control valve that is less expensive than conventional ones.

The control valve according to the invention supports a relatively simple resilient seal on the plunger. The plunger has a circumferentially extending groove for receiving a seal, one side of the groove being closed by a ring, the ring being made of plastic or other deflectable material for a snap fit over the plunger. . The ring provides circumferentially spaced, radially extending passageways for venting high pressure from the cavity defined by the plunger groove and ring.

The ring is designed to hold the seal on the plunger.

Accordingly, according to a feature of the invention, the control valve includes a circumferentially extending groove provided in the plunger, supported by the plunger and defining one side of the groove and an opposite side of the groove. a circumferentially extending ring cooperating to form a gap; and a circumferentially extending ring disposed within the groove and having a portion extending through the gap to engage a valve seating surface of the housing. and an elastic seal.

Therefore, the present invention has the advantage of being able to provide a simpler and more effective sealing mechanism than conventional ones, and also being able to securely hold the seal on the plunger. Another advantage of the present invention is that the simplified sealing mechanism allows the control valve body and plunger to be made of non-metallic or plastic materials, further reducing the cost of the control valve.

These and other features and advantages of the invention will become apparent from the following description of an embodiment, made with reference to the accompanying drawings.

In FIG. 1, the brake control valve, generally designated 10, includes a housing 12 having a bore 14 formed therein.

The hole 14 communicates with an outlet l6 which communicates with the surrounding atmosphere. The hole 14 has an outlet or outlet 18 and an inlet or supply outlet 20.
It also communicates with The bore 14 is stepped to form a large diameter portion 22 and a small diameter portion 24 which cooperate with each other to form a circumferentially extending shoulder 26 therebetween. The shoulder portion 26 forms a valve seat surface, which will be described later.

A valve actuating plunger, generally designated 28, is slidably received within the bore 14 and includes a stem 30 projecting from an end 32 of the nozzle 12. A knob 34 is mounted on the end of the stem 30, which is actuated in a conventional manner by the operator of the vehicle. Plunger 28 is stepped with a smaller diameter portion 36;
Large diameter portions 38 and shoulders 40 are formed therebetween. A fitting 42 closes the open end 32 of the housing 12 and provides an opening 44 through which the stem 30 extends. Mounting tool 42
is partially cut away to form a chamber 46 which communicates with the large diameter portion 22 of the bore 140 via a passageway 48 shown in phantom in FIG. Spring 50 ~ Shoulder 40
1 and press plunger 28 upwardly in FIG. 1 to the position shown. A passageway 52 extends through plunger 28 and communicates with the outer periphery of plunger 28 in an isolated area between conventional O-ring seals 54,56.

As shown in detail in FIG. 2, the plunger 28
The shoulder 40 is cut away to form a circumferentially extending groove generally indicated at 58. The groove 58 is on the top surface 6
0 and a tapered side surface 62. Also, shoulder part 4
0 is cut away to form a recess 64 and a circumferentially extending retaining ramp 66.

$・ An inwardly extending protrusion 70 is provided, and due to the flexibility of the ring 680, the protrusion 70 forms a retaining slope when the ring 68 is mounted on the plunger 28 in the position shown in FIG. 66 and snap-fitted into the recess 64. Ring 68 also includes another inward projection 72 that cooperates with surfaces 60, 62 of groove 58 to form a cavity for receiving a resilient seal 74. Seal 74 is a simple annular O-ring seal with a generally circular cross section in the free state. However, when the seal 74 and ring 68 are installed on the plunger 28, the protrusion 72 of the ring 68 is inserted into the groove 58.
It cooperates with the 0 face 60, 62 to deform the seal into the shape shown in FIG. Thus, portion 76 of seal 74
1 is pushed out through the gap formed between the protrusion 72 of 8 and the end of the tapered side surface 62.
Portion 76 forms a circumferentially extending bead that engages shoulder 26 as described below.

The ring 68 further includes circumferentially spaced, small diameter exhaust passages 78 for exhausting high pressure penetrating into the groove 58 at the rear of the seal 74, as described below.

In operation, a number of the components of control valve 10 are shown in the position they would be in when the release pressure is removed from the spring brake and the spring brake is activated when the vehicle is parked. In this condition, the portion of the plunger 28 supporting the O-ring seals 54,56 is inserted into the opening 44 of the fitting 42.
The fluid pressure at the inlet or supply port 20 is sealed since the passageway 52 is enclosed within the fluid pressure chamber. Because the bead 76 of the seal 74 is located away from the valve seating surface of the shoulder 26, substantially unrestricted fluid communication is permitted between the outlet 16 and the outlet or delivery port 18, allowing for substantially unrestricted fluid communication within the spring brake. The release pressure from the outlet 1 passes through the outlet or outlet 18
6.

When moving the vehicle, the plunger 28 is activated by the vehicle driver.
is moved downwardly in the figure to sealingly engage the bead 76 of the seal 74 with the valve seat surface formed on the shoulder 26. Due to the engagement between the bead 76 and the valve seat surface of the shoulder 26, the discharge port 1
6 and the outlet or outlet 18 is cut off. The downward movement of plunger 28 also causes passageway 52 to communicate with chamber 46 which communicates with large diameter portion 22 of bore 140. The outlet or outlet 18 also communicates with the large diameter portion 22 of the bore 140, so that the inlet or supply inlet 20 and the outlet or outlet 18 communicate with each other to communicate release pressure to the vehicle's spring brakes. Although the spring 50 biases the plunger 28 upwardly, the high fluid pressure level within the bore 14 acting on the unbalanced surface of the plunger 28 causes the spring 50 to bias the plunger 28 upwardly.
Because the zero force is overcome, the seal 74 remains in sealing engagement with the valve seating surface of the shoulder 26.

■ Even if the seal 74 is complete, high fluid pressure within the bore 14 may enter the groove 58 when the seal 74 is sealingly engaged with the valve seat surface of the shoulder 26. obtain. Due to the sealing engagement of bead 76 with the valve seating surface of shoulder 26, fluid is trapped within groove 58. When the vehicle is parked and the spring brake is activated, the plunger 28 is pulled upward in the figure 5, and the fluid pressure in the large diameter portion 22 of the hole 14 is immediately communicated to the outlet 16, so that the pressure level in the same portion is reduced. decreases rapidly. In conventional seals used in environments where high fluid pressures are rapidly reduced to much lower pressures, fluid pressure trapped within groove 58 cannot be vented through the seal, such that the pressure pushes the seal out of the groove. tended to cause the control valve to become inoperable. However, with the present invention, the high fluid pressure normally trapped within groove 58 can be vented via vent passageway 78. Furthermore, ring 68,
In particular, the protrusion 72 deforms the seal 74 and compresses it within the groove 58, thereby preventing the seal 74 from being forced out of the illustrated position.

As mentioned above, conventional control valves of this type require a fairly complex sealing mechanism, which is held on the plunger by a bolt. Therefore, it is impossible to make the plunger from non-metallic materials;
This type of control valve is considerably more expensive than valves made from non-metallic molded materials. Although not necessary in practicing the invention, the plunger can be made of a non-metallic material such as plastic.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a brake control valve according to the present invention, and FIG.
The figure is an enlarged sectional view of the portion 2 surrounded by the broken line in FIG. 1. 10... Brake control valve, 12... Housing, 14...
- Hole, 16... Discharge port, 18... Outlet or delivery port, 20
・・Inlet or supply port, 26・・Shoulder (valve seat surface), 28・
・Plunger, 52...Passage, 58...Groove, 6゛0...
Top surface, 62... Side surface, 64... Recess, 66... Holding slope, 68... Ring, 70. 72... Projection, 74...
Elastic seal, 76... portion (bead), 78... discharge passage. l'2

Claims (1)

[Claims] 1. An inlet (20) and an outlet (18) communicating with a fluid pressure source.
, a housing (12) defining an outlet (16) and a hole (14) communicating with the inlet, outlet and outlet;
The outlet (14) is slidably fitted into the hole (14) and the outlet (1
a plunger (28) movable from a first state in which the inlet (20) and the outlet (18) communicate with each other to a second state in which the inlet (20) and the outlet (18) communicate with each other; Sealing means (74, 58) provided on the plunger (28) to block communication to the discharge port (16) when the plunger (28) is in the second state;
68), the sealing means being supported by and cooperating with a circumferentially extending groove (58) provided in the plunger and the plunger (28); While forming a cavity, the side surface (62) of the groove (58)
) and a circumferentially extending ring (
a circumferentially extending resilient seal (74) disposed within the cavity and having a portion (76) extending through the gap to engage the valve seat surface (26) of the housing;
A control valve comprising: 2. A cross section of the seal (74) is different from a cross section of the cavity, and a portion (76) of the seal (74) is pushed out from the gap to form a bead extending in the circumferential direction. A control valve according to claim 1. 3. The seal (74) is an O-ring seal having a substantially circular cross section in a free state, and the cavity deforms the seal so that the portion (76) protrudes through the gap to form the bead. 3. The control valve according to claim 2, wherein: 4 The ring (68) absorbs the pressure that has entered the cavity when the cavity is exposed to a high pressure environment, and prevents the seal (7
4) circumferentially spaced evacuation passages (
78) The control valve according to claim 1 or 2, characterized in that the control valve is provided with: 78). 5 said plunger (28) is provided with a circumferentially extending retaining ramp (66) extending axially from said groove (58) and terminating in a circumferentially extending recess (64); 68) is characterized in that it has a radially inwardly extending protrusion (70) that engages the recess (64) and retains the ring (68) on the plunger (28). A control valve according to claim 4.