JPS6350760Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a pressure switch that can prevent chattering between the plunger and the terminal caused by slight fluctuations in oil pressure or vibrations of the engine, etc. This invention relates to a pressure switch that can minimize the difference in pressure.

Pressure switches that operate using hydraulic pressure are commonly used in automobiles and the like where hydraulic pressure is used. This pressure switch, when operated with proper oil pressure, lights up a brake light or prompts the engine to idle up, for example. When the operation is canceled, the brake lamp is turned off or the idle speed of the engine is reduced.

However, there is no problem when the pressure switch operates smoothly, but with conventional pressure switches, slight fluctuations in oil pressure or vibrations of the engine etc. can cause the plunger inside the pressure switch to This has the disadvantage that a chattering phenomenon is likely to occur in which the terminal and the terminal come into contact and separate in a short period of time, and this also causes a chattering phenomenon in relays and the like in the connected electric circuit.

In other words, the conventional pressure switch
As shown in the figure, for example, there is a main body 1 that is shared with the body of an oil pump, a piston rod 2 that is slidably installed inside the main body 1, and a piston rod 2 that is slidably installed inside the main body 1 adjacent to the piston rod 2. A plunger 3, a spring 4 that presses the plunger 3 in the backward direction (to the left in FIG. 1) with a constant repulsive force, and a terminal 5 attached to the main body 1 at an appropriate distance from the end surface of the plunger 3. It consists of an oil pipe 6 drilled in the main body 1.
Introduce oil to chamber A at an appropriate pressure, such as the discharge pressure from an oil pump associated with power steering operation, through
Forward direction of piston rod 2 (to the right in Fig. 1)
By sliding the plunger 3 over the repulsive force of the spring 4, the plunger 3 is slid in the forward direction. When the plunger 3 slides in the forward direction, the plunger 3 comes into contact with the terminal 5, and since a current is applied to the terminal 5, the current flows and operates the control device 7 connected to the terminal 5. , for example, to increase the engine speed.

By the way, if there is insufficient hydraulic pressure in chamber A, the plunger 3 should be careful not to contact the terminal 5 with its end face unless it receives enough hydraulic pressure to overcome the repulsive force of the spring 4. It is designed not to energize, but in the opposite case, that is, if the oil pressure in chamber A drops even slightly when plunger 3 and terminal 5 are in contact under proper oil pressure, energization can easily be turned off. It will be cancelled. That is, the plunger 3 can slide in the backward direction due to the restoring force of the spring 4 due to a slight change in the oil pressure, and as a result, the end face of the plunger 3 separates from the terminal 5. Then, when the oil pressure slightly increases in the A chamber, that is, returns to the proper oil pressure, the plunger 3 overcomes the repulsive force of the spring 4 and comes into contact with the terminal 5. That is,
Even a slight fluctuation in the oil pressure will cause a chattering phenomenon between the plunger 3 and the terminal 5. The slight fluctuation in oil pressure that causes this chattering phenomenon is unavoidable due to the functionality of current hydraulic systems, and the chattering phenomenon itself is designed to prevent contact between plunger 3 and terminal 5, which are normally in contact. It can also be caused by vibrations from engines, etc.

Therefore, the present invention has been developed to minimize the difference between the energizing force and the de-energizing pressure, and to prevent the chattering phenomenon that occurs between the plunger and the terminal due to slight fluctuations in oil pressure or vibrations of the engine, etc. The purpose of the present invention is to provide a push switch, and to achieve this purpose, the present invention has a structure including a piston rod slidably housed within the body, and a piston rod slidably housed within the body adjacent to the piston rod. the plunger, a spring that presses the plunger in the backward direction with a constant repulsive force, and a terminal attached to the main body at an appropriate distance from the end face of the plunger,
The piston rod slides in the forward direction due to the appropriate hydraulic pressure, and the plunger overcomes the repulsive force of the spring and slides in the forward direction, and its end surface contacts the terminal. When the appropriate hydraulic pressure is released, the plunger slides in the backward direction due to the restoring force of the spring. In the pressure switch whose end face is separated from the terminal, a friction member is attached to the outer circumferential surface of the plunger, and a drain passage is provided to return oil leaking from the gap between the outer circumference of the piston rod and the main body to the oil tank. It is characterized in that it is provided on the main body at the outer periphery of the contact portion with the plunger.

Hereinafter, the present invention will be explained based on the illustrated embodiments.

As shown in FIG. 2A, the pressure switch according to the present invention includes a piston rod 20 slidably housed in a main body 10, and
a plunger 30 slidably housed in the main body 10 adjacent to the plunger 30; a spring 40 that presses the plunger 30 in the backward direction (to the left in FIG. 2) with a constant repulsive force; and an end surface of the plunger 30. and a terminal 50 attached to the main body 10 at an appropriate interval.

In this embodiment, the main body 10 is shared with an oil pump (not shown), but it may be replaced with an independent main body 10 such as a casing as appropriate. good. However, in this case, the oil passage 60 that guides oil to the A chamber is of course formed separately from the main body 10.
In this embodiment, the main body 10 serves as a ground when current flows to the terminal 50. As shown by the broken line in FIG. 2A, a drain passage 11 is provided in the main body 10 at the outer periphery of the contact portion with the plunger 30.

The piston rod 20 is formed of a cylindrical body with an appropriate length, and is driven in the forward direction ( The plunger 30, which will be described later, slides in the forward direction.

The plunger 30 is connected to the piston rod 2.
0, it slides forward toward the terminal 50, and has a trunk 31 in the middle and a base 32 at the rear (left side in FIG. 2).
It also has a rod portion 33 at the front (right side in FIG. 2A). An annular groove 34 having an appropriate depth is formed in the intermediate body portion 31, and a friction member 35 is fitted into the annular groove 34. When the plunger 30 slides in the B chamber, this friction member 35 is operated at least in the backward direction (left side in FIG. 2).
It must be formed so as to generate the desired frictional force when sliding. Specifically, as shown in FIG.
The plunger 30 is formed so as to protrude slightly from the outer circumferential surface of the barrel 31, and easily falls down when the plunger 30 slides in the forward direction, and stands up when the plunger 30 slides in the backward direction. It works to generate a large frictional force.
In order to obtain the same effect as the friction member 35, the embodiments shown in FIGS. 3A and 3B can be used instead of the embodiment shown in FIG. 2B. That is,
Friction member 35 made of a rubber ring with a square cross section
(See FIG. 3A), the desired frictional force can be generated by the corner portion 37 not only in the backward direction of the plunger 30 but also in the forward direction. In addition, when the friction member 35 (see FIG. 3B) is made of a rubber ring having a cross section and is formed with a protrusion 38, the desired friction force can be obtained whether the plunger 30 moves forward or backward. Moreover, considering the function of the friction member 31, it is more preferable. The friction member 35 attached to the plunger 30 is made of a rubber member in any of the embodiments described above, but instead of this, another elastic material may be used. Also good.

The spring 40 is installed so as to surround the rod portion 33 of the plunger 30, and has one end adjacent to the end surface of the body portion 31 of the plunger 30 and the other end that connects the terminal 50 to the main body 10.
The plunger 30 is placed adjacent to the end surface of a spring seat 41 installed at the inner end of the plug 51 attached to the plug 51 to maintain a repulsive force that acts to stretch the spring 40 and press the plunger 30 in the backward direction. The spring 40 is compressed by a predetermined hydraulic pressure entering the A chamber, thereby allowing the plunger 30 to slide in the forward direction.

The terminal 50 allows connection of a relay terminal 52, and a plug 51 connects the main body 10 to the terminal 50.
However, since the main body 10 is grounded, the plug 51 and terminal 50 are
An insulator 53 is interposed in order to insulate the terminal from the terminal. In addition, in order to fix the terminal 50 to the plug 51, an O-ring 54 is interposed between the insulators 53, and a plain washer 55 is inserted between the insulators 53.
are interposed and tightened with a snap spring 56. Further, an O-ring 54 is provided to prevent oil leakage between the plug 51 and the C chamber communicating from the B chamber, that is, between the plug 51 and the main body 10.

In order to smoothly slide the plunger 30 in the B chamber, the tip of the rod 33 is fitted into a bearing 42 fitted in a spring seat 41 installed at the inner end of the plug 51. It is slidably supported.

The pressure switch according to the present invention configured as described above operates as follows. That is,
Oil pipe 60 communicating with an oil pump (not shown)
When a proper hydraulic pressure is generated in chamber A through this process, the piston rod 20 slides in the forward direction (to the right in FIG. 2). This sliding of the piston rod 20 causes the adjacent plunger 30 to overcome the repulsive force of the spring 40 and slide in the forward direction. This plunger 3
The end face of the plunger 30 comes into contact with the terminal 50 due to the sliding movement of the plunger 30 . As a result, since the current is applied to the terminal, current flows, which energizes a relay (not shown) in the electrical circuit connected to the terminal, causing, for example, an increase in the engine speed. Become.

When the plunger 30 is about to move slightly in the backward direction (to the left in Figure 2) due to slight fluctuations in the proper oil pressure or engine vibrations during the operation of this pressure switch, the plunger 30 30 is prevented from slight movement by the frictional force generated between the friction member 35 formed thereon and the inner surface of the B chamber of the main body 10. However, when it is no longer necessary to maintain the operating state of the pressure switch, that is, when the proper hydraulic pressure acting in chamber A is released, the restoring force of the spring 40 overcomes the frictional force. Since the plunger 30 is slid in the backward direction, the plunger 30
As a result of the retreat, the end face of the terminal 50 is separated from the terminal 50 and the current supply is discontinued.

As described above, according to the present invention, the plunger does not vibrate slightly in the backward direction due to slight fluctuations in oil pressure or vibrations of the engine, etc., and there is no chatter between the plunger and the terminal when the pressure switch is operating. No phenomenon occurs. As a result, the durability (quality) of the pressure switch can be improved, and there is no risk of causing chattering to the electrical components such as relays and microswitches connected to the terminal. There is an advantage that it is also possible to improve the durability of these electrical parts.

Furthermore, the difference between the energizing force and the energizing release pressure can be minimized by adopting a friction member that is not intended for sealing performance but for improving operability, and by forming a drain passage that prevents pressure from being trapped. ,
For example, when the present pressure switch is installed in a power steering system or the like of a vehicle, it becomes possible to suppress unnecessary engine driving, which has the advantage of being effective in improving the fuel efficiency of the vehicle.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a conventional pressure switch together with an oil pump main body, Fig. 2 A is a sectional view showing a pressure switch according to an embodiment of the present invention together with an oil pump main body, and Fig. 2 B is a sectional view showing a conventional pressure switch together with an oil pump main body. Third partially cutaway sectional view showing a plunger according to an embodiment of the invention
Figures A and B are cross-sectional views showing friction members according to other embodiments of the present invention. 10...Main body, 11...Drain passage, 20...
Piston rod, 30... Plunger, 31...
Body, 34... Annular groove, 35... Friction member, 36
...Annular lip, 38...Protrusion, 40...Spring, 50...Terminal.

Claims (1)

[Claims for Utility Model Registration] (1) A piston rod slidably housed inside the body, a plunger slidably housed inside the body adjacent to the piston rod, and a constant repulsion in the backward direction of the plunger. It consists of a spring that presses with force and a terminal attached to the main body at an appropriate distance from the end face of the plunger, and a piston rod that slides in the forward direction with appropriate oil pressure overcomes the repulsive force of the spring and moves the plunger in the forward direction. In a pressure switch, the plunger slides and contacts the terminal with its end face, and when the appropriate hydraulic pressure is released, the plunger slides in the backward direction due to the restoring force of the spring, and the end face moves away from the terminal. A pressure switch characterized in that a friction member is attached and a drain passage is provided in the main body at the outer periphery of the contact portion with the plunger for returning oil leaking from the gap between the outer periphery of the piston rod and the main body to the oil tank. . (2) The pressure switch according to claim 1, wherein the friction member fits into an annular groove formed in the body of the plunger. (3) The pressure switch according to claim 1, wherein the friction member is a rubber ring having an annular lip on its outer periphery. (4) The pressure switch according to claim 1, wherein the friction member is a rubber ring with a square cross section. (5) The pressure switch according to claim 1, wherein the friction member comprises a rubber ring having a cross-shaped cross section and provided with a protrusion.