JPH0799021A - Pressure switch - Google Patents

Abstract

PURPOSE:To prevent a spool from coming off, and also prevent working oil from leaking out of a drain passage when resin is ruptured or damaged due to over loading by installing a regulating member at the end section of the spool, and concurrently forming a land section i.n the spool. CONSTITUTION:A sliding hole 34 communicated with a pressure introducing hole 32 while being pivoted on an axial line O, is formed in a switch housing 33, and a locking hole 312 is formed on the switch chamber 310 side of the hole 34 in such a way that a step section 311 larger in diameter than the hole 34 can be formed therein. A regulating member 313A such as a snap ring and the like is fitted in the end section of a spool 35 so that the spool 35 does not fall, down in the hole 32 because of the hole 312. And a regulating member 313B such as a snap ring and the like, which is brought into contact with the lower end face of the housing 33 to prevent the spool 35 from coming off when the spool 35 on the left side of the axial line O is operated upward, is fitted in the other end section. Furthermore, a land section 37 is formed in the spool 35 in such a way that a communication hole 39 formed in a pump housing 31 is blocked when the member 313B is brought into contact with the housing 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used for detecting an increase in pressure in a hydraulic system, and in particular,
The present invention relates to a pressure switch suitable for detecting the hydraulic pressure around a hydraulic pump used in a hydraulic system for automobiles.

[0002]

2. Description of the Related Art Generally, a hydraulic power steering apparatus for an automobile, which is used in an automobile, is provided with a pressure switch for detecting a load pressure around the entire hydraulic system or a hydraulic pump. In such a device, when the load pressure of the hydraulic pump rises due to the steering device performing stationary steering while the engine is idling, the engine that supplies power to the hydraulic pump is May cause stalls. In order to prevent such an engine stall, the rotation speed of the engine is increased by the signal from the pressure switch. That is, a pressure switch is used as a signal transmission source for idle up.

By the way, as shown in FIG. 2, this pressure switch is formed in a pump housing 1, and a switch housing 3 is attached to a pressure introducing passage 2 into which a load pressure is introduced. A spool 5 that moves in the axial direction according to the load pressure is inserted in the switch housing 3, and a connector 15 that forms one electrical contact is installed on the upper portion. The connector 15 is supported by the switch housing 3 by a resin 16 which is injected and fixed between the connector 15 and the spacer 17.

A leaf spring 19 is fixed between the connector 15 and the spool 5 as the other electrical contact. The leaf spring 19 is electrically connected to the pump housing 1 from the switch housing 3 via the spacer 17 so as to be grounded to the body. A sheet member 18 is inserted on the spool 5 side of the leaf spring 19 in order to block the communication between the switch chamber 10 and the sliding hole 4 and keep the contact portion between the connector 15 and the leaf spring 19 airtight. There is.

When the spool 5 moves against the force of the leaf spring 19 due to the load pressure from the pressure introducing passage 2, the connector 15 and the leaf spring 19 come into contact with each other to establish conduction between them.
The connector 5 and the pump housing 1 are electrically connected to each other, and an idle-up signal is transmitted.

[0006]

In the above conventional technique, when a high-pressure load is applied from the pressure introducing passage 2, the resin 16 may crack, break, or break. In the unlikely event that the resin 16 is broken in this way, there is a problem in that the spool 5 jumps out of the sliding hole 4 and the hydraulic oil leaks out.

[0007]

The pressure switch of the present invention has been made to solve the above-mentioned problems, and is fitted to a pump housing having a pressure introduction hole for introducing pressure and the pump housing. Switch housing, a slide hole formed in the switch housing and communicating with the pressure introducing hole, a switch chamber formed in the switch housing and connected to the slide hole, and a pressure inserted in the slide hole. A spool that receives and operates in the axial direction,
A restricting member that is attached to an end portion of the spool and abuts against the switch housing to restrict an operating range of the spool in the axial direction; a connector that is provided in the switch chamber and serves as one electric contact; A spacer inserted in the switch chamber, a resin injected between the connector and the spacer to fix the two together, and a sheet member installed between the sliding hole and the switch chamber to block the flow of both. A leaf spring installed between the sliding hole and the switch chamber on the connector side of the sheet member and forming the other electrical contact, and when the spool moves to the connector side and the regulating member comes into contact with the switch housing. And a land portion provided on the spool so as to close the drain passage provided in the switch housing.

[0008]

When the pressure is introduced from the pressure introducing hole, the pressure is applied to the spool inserted in the sliding hole formed in the switch housing. Then, when a preset pressure is applied to the spool, the spool is moved against the repulsive force of the leaf spring, and the leaf spring bends toward the connector and comes into contact with the connector.
At this time, even if the resin is broken due to a high pressure exceeding the allowable value, the regulating member attached to the spool contacts the switch housing to prevent the spool from coming off.
In addition, the land portion formed on the spool closes the drain passage to prevent the hydraulic oil from flowing out.

[0009]

EXAMPLE An example of the present invention will be described with reference to FIG. Figure 1
As shown in FIG. 3, the pump housing 31 is formed with a pressure introduction hole 32 for introducing the load pressure from the unillustrated pump.
A fitting hole 32A having a thread groove is opened at the upper portion where the pressure introducing hole 32 is formed. A switch housing 33, which is the body of the pressure switch, is screwed into the fitting hole 32A.

A sliding hole 34 is formed in the switch housing 33 so as to communicate with the pressure introducing hole 32 about an axis O, and a spool 35 is slidably inserted in the sliding hole 34. Has been done. Restricting members 313A and 313B such as snap rings are fitted to both ends of the spool 35 protruding from the sliding hole 34. A land portion 37 and a communication groove 38 are formed on the spool 5, and the switch housing 33 has an axis O.
A communication hole 39 is formed orthogonally to. Further, the pump housing 31 is formed with a drain hole 36 communicating with the fitting hole 32A.

The drain hole 36, the communication hole 39, the land portion 37, and the communication groove 38 communicate with each other, so that the spool 35 and the sliding hole 34 are lubricated and the clearance between the spool 35 and the switch housing 33 is penetrated. A drain passage for discharging the operating oil from the drain hole 36 is formed. The sliding hole 34 is formed in the switch housing 33.
And a switch chamber 310 is formed. On the switch chamber 310 side of the sliding hole 34, a locking hole 312 is formed so that a step portion 311 having a larger diameter than the sliding hole 34 is formed.

A regulating member 313A such as a snap ring is fitted to the end portion of the spool 35 so that the spool 35 does not fall into the pressure introducing hole 32 in the lower part of the figure by the locking hole 312. Further, at the other end, as shown by a broken line on the left side of the axis O, when the spool 35 is operated upward in the drawing, a snap ring or the like for coming into contact with the lower end surface of the switch housing 33 to prevent the spool 35 from coming off. The regulation member 313B is fitted. Further, on the spool 35, the land portion 37 is formed on the spool 35 so as to close the communication hole 39 formed in the pump housing 31 when the regulating member 313B comes into contact with the switch housing 33.

Inside the switch chamber 310, a connector 315 which makes one electrical contact centering on the axis O is provided. A wire harness or the like (not shown) is attached to the tip of the connector 315, and an electric signal is transmitted through the wire harness. A ring 300 is fitted into the groove 301 at the end of the connector 315 and is integrally attached to the connector 315.

A resin 316, which is an electrical insulator, and a conductive spacer 317 are interposed between the connector 315 and the switch housing 33. The minimum diameter portion K of the spacer 317 is formed to have a diameter smaller than the outer diameter of the ring 300. These connectors 3
15, the resin 316, and the spacer 317 are the connector 31 separately.
The resin 316 is poured between the spacer 5 and the spacer 317 and fixed to both of them to integrally form the three.

A rubber plate 302 is fitted in the connector 315, and the connector 3 is fitted in the rubber plate 302.
A hole 302A is formed in the center for fitting 15. Since the diameter of the hole 302A is smaller than the diameter of the connector 315, an appropriate tightening margin is given to the connector 315, so that the connector 315 is sealed.

A sheet member 318 such as a Kapton sheet is installed between the sliding hole 34 and the switch chamber 310 to block the flow of the two, and the connector 31 is also provided.
A leaf spring 319, which is in contact with the spacer 317 and serves as the other electrical contact, is installed on the fifth side. Therefore, the leaf spring 319, which is the other electric contact, is connected from the switch housing 33 to the pump housing 31 via the spacer 317.
The body is grounded by conducting to.

A groove is circumferentially formed in the step 321 at the boundary between the switch chamber 310 and the sliding hole 34, and an O-ring 322 is fitted in this groove. And the sealing property of the end of the sheet member 318 is enhanced. Therefore, the switch chamber 310 is always kept airtight. Then, the thin portion 323 of the upper opening portion of the switch housing 33 in the drawing is crimped. The length of the thin portion 323 is set in advance so that the crimping diameter is smaller than the outer diameter of the ring 300. Further, since the crimping diameter is smaller than the outer diameter of the rubber plate 302, the caulking presses down the rubber plate 302 and seals between the rubber plate 302 and the thin portion 323 of the switch housing 33. .

Further, due to this caulking, the spacer 3
The plate spring 319 and the sheet member 318 are pressed against the step portion 321 of the switch housing 33 by pressing 17 to fix the position. Here, the state when no load pressure is applied from the pressure introduction hole 32 is shown on the right side of the axis O, and the state when the load pressure is applied is shown on the left side.

State when assembled, that is, the pressure introducing hole 32
In the right-side state where no load pressure is applied from, the head portion 324 of the spool 35 on the connector 315 side is in contact with the leaf spring 319 via the sheet member 318, and the leaf spring 319 and the connector 315 are connected to each other. A certain gap is provided between them. Next, the operation of this pressure switch will be described.

When the steering device is steered and steered during idling rotation, the load pressure of the hydraulic pump rises. Then, the load pressure is introduced from the pressure introducing hole 32, and the spool 35 receives the load pressure. When the load pressure becomes larger than the repulsive force of the leaf spring 319, the load 35 causes the spool 35 to be guided by the sliding hole 34 and move upward in the drawing. Then, the plate spring 319 is bent by the head portion 324 of the spool 35 via the sheet member 318, and the state changes from the right side to the left side in FIG.

Then, the sliding hole 3 is formed by the sheet member 318.
4 is cut off, and the connector 315 and the leaf spring 319, which are held airtight, are brought into contact with each other. by this,
The switch is electrically turned on, and the connector 315
And the pump housing 31 are electrically connected. As a result, the plate spring 31 body-grounded through the pump housing 31 through the spacer 317 and the switch housing 33.
An electric signal is transmitted from the connector 9 through the connector 315, and the engine is idled up based on the electric signal.

At this time, in the unlikely event that the load pressure larger than the normal load pressure is continuously applied and the resin 316 is damaged or destroyed and the connector 315 is pulled out, the spool 35 of the spool 35 is drawn as indicated by the broken line on the left side in FIG. The regulating member 313B fitted in the lower end portion contacts the lower end surface of the switch housing 33 to prevent the spool 35 from coming off. Therefore, spool 3
Since 5 is prevented from coming out, the hydraulic oil does not leak out from the pressure introducing hole 32 to the outside. Further, the land portion 37 of the spool 35 is connected to the drain hole 36 by the communication passage 3
Block 9 to prevent hydraulic oil from flowing out of the drain hole.

[0023]

Since the pressure switch of the present invention has a spool member slidably inserted in a slide hole of a switch housing, a restricting member for restricting an axial operating range is attached to the end portion of the spool. Even if the resin is damaged or destroyed due to overload, the spool will not come out. Therefore, the hydraulic oil does not leak outside. Furthermore, since the land part is formed on the spool so as to block the drain passage,
The hydraulic oil will not flow out from the drain passage. Therefore, it is possible to prevent seizure of other parts such as the pump due to insufficient hydraulic oil.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a pressure switch of the present invention.

FIG. 2 is a cross-sectional view showing a conventional pressure switch.

[Explanation of symbols]

 31 pump housing 32 pressure introducing hole 32A fitting hole 33 switch housing 34 sliding hole 35 spool 300 ring 302 rubber plate 313A, 313B regulating member 310 switch chamber 315 connector 316 resin 317 spacer 318 sheet member 319 leaf spring 324 head part K spacer Minimum diameter part

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoichiro Maekawa 1-1-1, Asahi-cho, Kariya city, Aichi Toyota Koki Co., Ltd.

Claims (1)

[Claims] 1. A pressure switch for detecting pressure in a hydraulic circuit of a hydraulic system, a pump housing having a pressure introducing hole for introducing pressure, a switch housing fitted to the pump housing, and the switch. A slide hole formed in the housing and communicating with the pressure introducing hole, a switch chamber formed in the switch housing and connected to the slide hole, and a slide chamber inserted in the slide hole and receiving pressure to operate in the axial direction. A spool, a restricting member that is attached to an end portion of the spool and contacts the switch housing to restrict an axial operating range of the spool, and a connector that is provided in the switch chamber and forms one electrical contact,
A spacer inserted into the switch chamber around the outer periphery of the connector, a resin injected between the connector and the spacer to fix the two together, and a spacer installed between the sliding hole and the switch chamber to distribute the two. A sheet member that shuts off the switch, a leaf spring that is installed on the connector side of the sheet member between the sliding hole and the switch chamber, and serves as the other electrical contact, and the spool moves to the connector side so that the regulating member switches. A pressure switch comprising: a land portion provided on the spool so as to close a drain passage provided on the switch housing when the housing comes into contact with the housing.