JPH0129703Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a piston-type pressure switch, in particular a seal at both ends of a plunger that moves forward and backward relative to a terminal on the atmospheric pressure side in response to the introduction pressure on the high pressure side. This invention relates to an improvement in a pressure switch that can appropriately ensure the performance of the pressure switch.

[Conventional technology]

This type of pressure switch is used, for example, in a power steering system to reduce the steering force of a car, by sensing when the oil pressure in the hydraulic circuit from the oil pump suddenly increases during steering and reducing the engine's idling speed. It is used as a sensor to increase engine speed and prevent engine stalling. Conventionally, such pressure switches have been disclosed in Japanese Utility Model Application Publication No. 57-161840,
Various structures have been proposed in Japanese Utility Model Publication No. 59-43039, Japanese Utility Model Publication No. 45-11143, and Japanese Utility Model Publication No. 45-8247.

That is, this type of piston-type pressure switch generally has a cylindrical electrical main body,
A terminal terminal is inserted through the terminal terminal while maintaining an electrically conductive state at one end thereof, and a plunger, etc. is supported slidably within the main body and is normally biased in a direction away from the terminal terminal by a spring or the like. We are prepared. Then, the hydraulic pressure on the high pressure side of the hydraulic circuit as described above is guided to the other end of this plunger, and when the pressure exceeds the set pressure, the plunger is moved to the terminal terminal side that is connected to atmospheric pressure. By bringing the conductive plunger into direct contact or indirectly with the conductive member, the switch is electrically turned on, and the required control operation can be performed using the electrical signal.

[Problem that the invention attempts to solve]

By the way, in the pressure switch having the above-mentioned conventional structure, in order to ensure sealing performance at the sliding portion of the plunger that moves back and forth with respect to the terminal terminal, which is at atmospheric pressure in response to high inlet pressure, the plunger and Conventionally, it has been common practice to interpose an O-ring having a required elastic force between the sleeve or main body that supports the O-ring. That is, such an O-ring is interposed between the plunger and a member that supports it to seal between the high pressure chamber and the atmospheric chamber formed at both ends of the plunger, and furthermore, It also has the function of optimizing the state of movement of the plunger by the sliding resistance generated by its elastic force when the plunger moves.

However, in the above-mentioned conventional configuration, both ends of the O-ring have a gap between them and the atmospheric chamber at the other end of the plunger, which is connected to the atmosphere, due to an increase in the introduction pressure acting on one end of the plunger. Since the pressure difference becomes large, problems such as large deformation of the O-ring within the recessed portion due to the fluid pressure on the high-pressure side arise. and,
When such deformation occurs, the repulsive force associated with the amount of deformation causes the sliding resistance that acts during the sliding operation of the plunger to be excessive, leading to a reduction in sealing performance due to wear and even hysteresis. It has drawbacks such as malfunction of the plunger, and it is desired to take some kind of measure to solve these problems.

[Means for solving problems]

In order to meet such demands, the pressure switch according to the present invention has a cylindrical main body that has a terminal terminal passed through and held at one end, and is slidably mounted on the other end of the main body and has an outer end. A plunger is moved toward the terminal terminal side, which is at atmospheric pressure due to the fluid pressure on the high pressure side applied to the body, and a plunger is inserted into an annular groove formed in the part near the terminal terminal between this plunger and the main body. This O-ring is provided with an O-ring, and a recess is provided in a portion of the annular groove for inserting the O-ring on the opposite side from the terminal terminal, and this recess is connected to the drain side.

[Effect]

According to the present invention, the fluid pressures acting on both ends of the O-ring are atmospheric pressure, which is both low pressure, and drain pressure, which is approximately equal to atmospheric pressure, so even if the fluid pressure increases on the high-pressure chamber side, The deformation of the O-ring, which causes excessive sliding resistance as in the past, is eliminated, and as a result, appropriate sliding resistance can be obtained to ensure proper sliding movement of the plunger, and sealing due to O-ring wear etc. is eliminated. It can eliminate problems such as a decline in sexuality.

[Example] Hereinafter, the present invention will be explained in detail using an example shown in the drawings.

FIG. 1 shows an embodiment of the pressure switch according to the present invention. First, in the figure, the general structure of the pressure switch, which is indicated by the reference numeral 1, will be briefly described. The main body 2 is formed of a conductive material to have a substantially cylindrical shape and has a flange 2a formed at one end thereof. It is provided to be screwed into a screw hole 4 formed in a housing 3 of a fluid device, device, etc. Note that 4a and 4b in the figure are O-rings interposed between the main body 2 and the screw hole 4.

Reference numeral 5 denotes a terminal terminal that is disposed through the outer end side of the main body 2 by insulating rings 6a, 6b, an O-ring 7, etc. while being held by a conductive ring, which will be described later.
is connected to a control circuit (not shown). Note that 8a and 8b in the figure indicate the settling of this terminal terminal 5.

Reference numeral 10 is inserted into the internal space 11 of the main body 2 from the other end side, and its inner end is locked at a stepped portion 11a formed in the center of the internal space 11 via a spacer 12 or the like. In the sleeve,
Inside this sleeve 10, the terminal terminal 5
The plunger 1 is moved forward and backward relative to the inner end 5a of the plunger 1.
3 is slidably loaded. In addition, 10 in the figure
Reference character a denotes an O-ring that is interposed on the outer periphery of the sleeve 10 and seals between the sleeve 10 and the main body 2 side. Further, reference numeral 9 in the figure denotes a locking ring (see FIG. 2) having a substantially G-shape that is attached to the open end side within the internal space 11 of the main body 2, and this locking ring 9 is
The sleeve 10 is locked at its outer periphery 9a, and the plunger 13 is locked at the same time as the sleeve 10 at the inwardly bent locking part 9b to prevent it from coming off, reducing the number of parts to be installed. This has the advantage that it can be reduced.

The inner end of the plunger 13 is moved into the atmospheric chamber 14 formed between the inner end 5a of the terminal terminal 5 and the inner end 5a of the terminal terminal 5 by being pushed and moved to the left in the figure by the plunger 13. , a conductive retainer 15 that contacts the terminal terminal 5 side is movably accommodated, and this retainer 15 is always in contact with the plunger 13 side by a conductive spring 16 installed in the atmospheric chamber 14. It is energized as follows. The retainer 15 is formed of a conductive plate material so that the entire retainer 15 has a substantially circular shape and its central portion bulges toward the terminal terminal 5, and one end of the spring 16 is in contact with the retainer 15. On the other hand, the other end of this spring 16 is
When the retainer 15 comes into contact with a conductive ring 17 interposed in the atmospheric chamber 14 of the main body 2 and is locked, and the retainer 15 comes into contact with the terminal terminal 5, the spring 16 and the conductive ring 17 The structure is such that it is connected to the ground on the main body 2 side via.

On the other hand, the bottom side of the screw hole 4 of the housing 3 and the inner end side of the main body 2 are connected to a high pressure side such as the discharge side of the oil pump constituting the hydraulic circuit via a pressure introduction hole 8a. A high pressure chamber 18 in which
It is configured such that it is brought into contact with the terminal terminal 5 against the urging force of.

The plunger 13, which is slidably supported within the sleeve 10 described above, has an annular groove portion 1 formed on the inner end side of the sleeve 10 on the atmospheric chamber 14 side.
9 is slidably supported with the required sliding resistance being applied by an O-ring 20 fitted into the inside.
Atmospheric chambers 14 at both ends of the plunger 13 are formed at this part.
and the high pressure chamber 18 are in a sealed state.

Now, according to the present invention, in the pressure switch 1 having the above-described configuration, the plunger 13 is moved toward the terminal terminal 5 (atmospheric chamber 14) by the fluid pressure on the high pressure chamber 18 side applied to the outer end side.
A recess 21 is formed in the part of the O-ring 20 on the opposite side to the terminal terminal 5 (on the high pressure chamber 18 side), which is inserted in the annular groove 19 formed in the part near the terminal terminal 5 between the main body 2 and the main body 2. At the same time, this recess 21 is provided with passage holes 22, 2 on the drain side.
It is characterized in that it is connected via wires 3, 24, etc. Here, the above-mentioned depression 21
is formed along the entire inner circumference of the sleeve 10, and is formed by an annular passage groove 25 formed between the outer circumference of the sleeve 10 and the main body 2,
A passage hole 22 protruding from the sleeve 10 is connected to a passage hole 23 on the main body 2 side, and this passage hole 23 is connected to the passage hole 23 on the housing 3 side.
4, it is connected to an oil tank or the like on the hydraulic circuit side (not shown).

According to such a configuration, the O-ring 2
Since the fluid pressures acting on both ends of 0 are atmospheric pressure, which is both low pressure, and drain pressure, which is approximately equal to atmospheric pressure, even if the fluid pressure increases on the high pressure chamber 18 side, it will not be excessively high as in the conventional case. Deformation of the O-ring 20 that causes sliding resistance is eliminated, and as a result, appropriate sliding resistance can be obtained to ensure proper sliding movement of the plunger 13, and sealing performance due to wear of the O-ring 20 is prevented. This can eliminate problems such as deterioration.

Furthermore, if such a configuration is adopted, the sliding resistance and hysteresis for the plunger 13 will be reduced.
Since it is set by tightening the O-ring 20, it has the advantage that it can be adjusted freely.

Note that the present invention is not limited to the structure of the embodiment described above, and the shape, structure, etc. of each part of the pressure switch 1 may be modified and changed as appropriate. For example, in the above-mentioned embodiment, the plunger 13 is supported slidably within the sleeve 10 disposed inside the main body 2, but the present invention is not limited to this, and as shown in FIG. As such, the plunger 13 may be slidably supported within the shaft hole 30 formed in the main body 2.

Furthermore, the pressure switch 1 according to the present invention is not limited to power steering as in the embodiments described above, but can be applied to various fluid circuits, fluid devices, devices, etc. in various fields to exert its effects. be.

[Effect of idea]

As explained above, according to the pressure switch according to the present invention, the terminal terminal side, which is slidably loaded in the main body and is brought to atmospheric pressure by the fluid pressure on the high pressure side applied to the outer end, A movable plunger, and an O-ring inserted in an annular groove formed between the plunger and the main body in a portion closer to the terminal terminal, and the annular groove for inserting the O-ring on the opposite side from the terminal terminal. Since a recess is formed in the O-ring part and this recess is connected to the drain side, the fluid pressure acting on both ends of the O-ring is low pressure, despite the simple and inexpensive structure. Since the drain pressure is approximately equal to the atmospheric pressure, even if the fluid pressure increases on the high-pressure chamber side, the deformation of the O-ring, which causes excessive sliding resistance as in the past, will no longer occur. It is possible to obtain suitable sliding resistance of the plunger and ensure proper sliding operation of the plunger, as well as
It has various excellent practical effects, such as being able to eliminate problems such as deterioration of sealing performance due to ring wear, etc.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view showing one embodiment of the pressure switch according to the present invention, Fig. 2 is a side view showing a G-shaped locking ring, and Fig. 3 is a longitudinal cross-sectional view showing another embodiment of the present invention. It is a front view. 1...Pressure switch, 2...Main body, 3...
... Fixed side housing, 5 ... Terminal terminal, 1
0... Sleeve, 11... Internal space, 13... Plunger, 14... Atmospheric chamber, 15... Retainer,
16... Spring, 17... Conductive ring, 1
8... High pressure chamber, 18a... Pressure introduction hole, 19...
Annular groove, 20... O-ring, 21... recess, 2
2, 23, 24...Drain passage hole, 25...Annular passage groove, 30...Shaft hole.

Claims (1)

[Scope of utility model registration request] A conductive cylindrical main body with a terminal terminal passed through and held in an insulated state at one end, and a high voltage that is slidably loaded from the other end of the main body and applied to the outer end. A plunger that moves according to the pressure difference between the fluid pressure on the side and the atmospheric pressure on the terminal side, and the plunger is inserted in an annular groove formed in the part near the terminal between the plunger and the main body. Equipped with an O-ring,
A recess is provided in the annular groove in which the O-ring is inserted, on the opposite side of the terminal terminal, and
This pressure switch is characterized by connecting this recess to the drain side.