JPH04102532U - pressure switch - Google Patents

Abstract

(57) [Summary] [Purpose] Reduce the radial dimension of a pressure switch, which is made by integrally incorporating each component inside a plug nut that closes the pressure path, to reduce the size, and reduce the number of parts to reduce product cost. lower. [Structure] The large-diameter cylindrical portion 11a of the storage case 11 manufactured by molding plate material is press-fitted and fixed into the plug nut 10, and the small-diameter cylindrical portion 11b is fitted into the pressure guide path 30. As a result, the pressure receiving spool 12, the movable contact 14, the fixed contact 15, and the coil spring are placed in the storage chamber formed between the plug nut 10 and the large diameter cylindrical portion 11a.
Incorporate 16. Then, movement of the pressure receiving spool 12 in the direction urged by the coil spring 16 is restrained by pressing against the stepped portion between the large diameter cylindrical portion 11a and the small diameter cylindrical portion 11b.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is based on hydraulic pressure, which is the source of the operating pressure for various hydraulic devices installed in automobiles. A pressure switch that is attached to the discharge side of a pump and operates in response to the hydraulic pressure generated by the pump. Regarding the

0002

[Conventional technology]

In recent years, automobiles are equipped with power steering devices, automatic transmission devices, etc. Equipped with various hydraulic devices to facilitate operation using hydraulic pressure, The engine is installed on the vehicle as the source of the working hydraulic pressure for these hydraulic systems. A driven hydraulic pump is used.

0003 By the way, the car engine depends on the load and throttle opening at that time. The hydraulic pump rotates at a predetermined rotational speed and is driven by the engine. The load required to drive the hydraulic pressure is determined by the state of the hydraulic power destination, for example, The drive load of the hydraulic pump that generates the working pressure of Therefore, in automobiles equipped with a power steering system, the steering wheel When the operation is performed, an increase in the driving load of the hydraulic pump causes a decrease in engine speed. This may lead to frequent engine stoppages.

0004 The hydraulic pump also circulates sealed oil in a closed tank with a limited volume. Therefore, when starting an engine in a cold region, the oil temperature is low and the viscosity is high. In this case, the driving load on the hydraulic pump is higher than normal, which can also cause the engine to stop. There is a possibility that it will come.

[0005] Therefore, in automobiles equipped with power steering devices, automatic transmission devices, etc., operating hydraulic pressure is Detects an increase in the driving load of the hydraulic pump, which is the source of this, using its discharge pressure as a medium. However, when this detection result exceeds a predetermined value and the engine speed is low, the throttle opening A device that prevents the engine from stopping by automatically increasing the Conventionally, a hydraulic pump device is provided as a means for detecting the discharge pressure. Pressure switches that are attached to a casing have been put into practical use.

[0006] This pressure switch has a conductor connected to the casing of the hydraulic pump and communicating with the discharge side of it. A pressure path and a mounting hole that is connected to the end of the pressure path and opens to the outside are formed, and the mounting hole and The internal pressure of the pressure channel is applied to the inner space of the plug nut screwed and fixed to the open end of the plug nut. A pressure-receiving spool that receives pressure at one end and moves, and a movable one fixed at the other end of the spool. A contact and a fixed contact facing the movable contact are arranged to prevent excessive internal pressure in the pressure path. When it rises, the pressure receiving spool that receives this pressure moves against the spring force of the biasing spring. The movable contact and the fixed contact are configured to be in contact with each other.

[0007] Furthermore, Utility Model Publication No. 2-4428 discloses that a pressure receiving spool is slidable on the plug nut. A pressure switch is disclosed in which a holder is inserted and fixed to hold the pressure switch. Figure 2 shows this pressure. FIG. 3 is a longitudinal cross-sectional view of the force switch.

[0008] This pressure switch 2 is connected to the end of the pressure channel 30 and is connected to the casing of the hydraulic pump. A cylindrical plug nut 20 is screwed and fixed into the mounting hole 31 that opens to the outside of 3. A round rod-shaped pressure receiving spool is attached to one side of the plug nut 20 (the side facing the pressure path 30). A cylindrical sleeve 21 that slidably holds the cylindrical sleeve 22 is fitted inside the sleeve 21, and the stops on both sides are It is clamped and fixed between the rings 21a and 21b, and is also inserted into the other side of the plug nut 20 by passing through it and attaching it to the outside. Attach the fixed terminal 23 protruding from the fixed terminal 23, and connect the fixed contact 25 formed at the base end of the fixed terminal The movable contact 24 attached to the tip of the pressure receiving spool 22 is opposed to the movable contact 24. A coil spring 26 is interposed between the moving contact 24 and the plug nut 20, and this coil spring 26 The pressure receiving spool 22 is biased toward the pressure guiding path 30 by the spring force of the pressure receiving spool 22. There is.

[0009] In other words, in this pressure switch 2, all the components are inside the plug nut 20. Since it is integrated, it can be attached to an appropriate test machine after assembly is completed to test its behavior. It has the advantage that the test can be easily performed.

0010

[Problem that the idea aims to solve]

However, in this pressure switch 2, the sleeve 21 is inserted inside the plug nut 20. It has a triple structure in which a pressure receiving spool 22 is fitted inside the sleeve 21, Additionally, there is a gap between the sleeve 21, the pressure receiving spool 22, and the plug nut 20. It is necessary to insert O-rings 27 and 28 to seal the gap, and these mounting grooves are formed. Therefore, the sleeve 21 has to be made thick, so the overall radial dimension is There is a limit to reduction, that is, miniaturization, and the desired position in the hydraulic pump casing. It was sometimes difficult to install the .

[0011] In addition, in order to clamp and fix the sleeve 21, and in the biasing direction by the coil spring 26, In order to restrain the movement of the pressure receiving spool 22, a pair of retaining rings 21a and 21b as described above are provided. The number of component parts is large, and many parts require machining. However, there are limits to the reduction of assembly and processing man-hours, making it difficult to reduce product costs. There is also a problem.

0012 The present invention was developed in view of the above circumstances, and is designed to completely remove the inside of the plug nut. It is possible to incorporate all kinds of components without increasing the radial dimension, resulting in a compact design. To provide a pressure switch that can reduce the number of processing and assembly steps. With the goal.

[0013]

[Means to solve the problem]

The pressure switch according to the present invention receives the internal pressure of the pressure channel at one end, and applies the biasing spring. A pressure receiving spool that moves against a spring force, a movable contact fixed to the other end of the spool, and A fixed contact facing the movable contact is attached to a plug nut fixed to the end of the pressure path. The contact between the two contacts corresponds to the movement of the pressure receiving spool. In a pressure switch used to detect an excessive increase in internal pressure, the plug nut The pressure receiving spool, the biasing spring, the movable contact and the A large-diameter cylindrical portion forming a storage chamber for a fixed contact, and a large-diameter cylindrical portion that is connected to the other side of the cylindrical portion and the pressure guiding path. A small-diameter cylindrical part that fits into the case is integrally formed from a plate material, and The pressure receiving spool is moved between both cylindrical parts of the storage case by the spring force of the biasing spring. It is characterized by being pressed against the step part of the.

[0014]

[Effect]

In this invention, a storage case consisting of a large-diameter cylindrical part and a small-diameter cylindrical part connected to each other is made of a board. Constructed by molding material, one side of the large diameter cylindrical part is press-fitted into one side of the plug nut. A storage chamber is formed between the two, and a pressure receiving spool, its biasing spring, movable contacts and A fixed contact is integrated into this storage chamber, and the biasing direction by the biasing spring is Move the pressure receiving spool to the step between the small diameter cylindrical part and the large diameter cylindrical part of the storage case. The pressure receiving spool is pressed against and restrained.

[0015]

【Example】

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof. Figure 1 is related to the present invention. FIG. 3 is a longitudinal cross-sectional view of the pressure switch. 3 in the figure is the casing of the hydraulic pump, and The casing 3 includes a pressure path 30 that guides the discharge pressure of the hydraulic pump, and an end of this pressure path 30. A mounting hole 31, which is a concave hole that is connected to the end and opens to the outside, is formed. Regarding this invention The pressure switch 1 has a plug nut 10 screwed into the opening of the mounting hole 31. A pressure receiving spool 12, which receives the internal pressure of the pressure guide path 30 at one end thereof, is provided in the inner space. A movable contact 14 fixed at the other end of the pressure spool 12, and a fixed contact facing the movable contact 14. 15 contacts are arranged respectively.

[0016] The side of the plug nut 10 facing the pressure path 30 is constructed by press forming a plate material. A storage case 11 is press-fitted and fixed. This storage case 11 is for plug nuts 10. One side of the large-diameter cylindrical portion 11a serving as the press-fit end has an outer diameter approximately equal to the inner diameter of the pressure guiding path 30. It has a shape in which small diameter cylindrical parts 11b are connected coaxially, and this small diameter cylindrical part 11b is By fixing the lug nut 10 as described above, the lug nut 10 is fitted into the pressure channel 30 for a predetermined length. Ru.

[0017] The pressure receiving spool 12, movable contact 14, and fixed contact 15 are press-fitted into the large diameter cylindrical portion 11a. It is housed in a cavity formed inside the plug nut 10 by fixation. cone A pressure-receiving base with a small diameter cylinder coaxially connected to the bottom of the base and shaped as shown in the figure. To install the pool 12, slide the cylindrical part onto the small diameter cylindrical part 11b of the storage case 11. A coil spring 16 is fitted between the plug nut 10 and the flange edge provided around the bottom of the truncated cone. is inserted to bias the pressure guide path 30 toward the pressure guide path 30. In addition, the truncated cone portion The movable contact 14, which has a spherical head at its tip, embeds its base for a predetermined length. It is inserted and fixed.

[0018] With the above installation, the pressure receiving spool 12 is moved into the storage case by the spring force of the coil spring 16. Both cylindrical parts of the base 11 are pressed against the stepped part between 11a and 11b, and are pressed against the tip of the cylindrical part. Due to the internal pressure of the pressure guide path 30 that is applied, the coil spring 16 is pushed in the opposite direction to the biasing direction of the coil spring 16. The internal pressure of the pressure path 30 is increased along with the movable contact 14 fixed at the tip. As it rises, it moves in a direction closer to the plug nut 10.

[0019] On the other hand, the plug nut 10 has a pair of supports made of an insulator that penetrate inside and outside the shaft center of the plug nut 10. A fixed terminal 13 is mounted supported by bearing rings 13a and 13b, and the fixed contact 15 is is fixed to the inner end of the fixed terminal 13, and is secured by the plug nut 10 and the storage case 11. The head of the movable contact 14 is closely opposed to the head of the movable contact 14 in the enclosed storage chamber. Nao you The fixed terminal 13 is a connection terminal 4 using a plate-shaped terminal for automobiles, so-called It constitutes the male side terminal of the stone type terminal, and the adoption of this connection terminal 4 More reliable conduction to the fixed contact 15 can be obtained.

[0020] This pressure switch 1 is attached to the pressure guide path 30 that is the object of pressure detection. Install the plug nut 10 by screwing it into the hole 31, and attach the connecting terminal to the fixed terminal 13. It is used by applying a predetermined voltage through the terminal 4. Then, the internal pressure of the pressure path 30 becomes excessive. When the internal pressure rises to It slides along the small diameter cylindrical portion 11b of the storage case 11 against the spring force of the When the movable contact 14 fixed at the tip of the pressure receiving spool 12 contacts the fixed contact 15, The fixed terminal 13 is connected to the bolt via the pressure receiving spool 12, the storage case 11 and the casing 3. De-earthed and a energized state is obtained, whereby an increase in the internal pressure of the pressure conduction path 30 is detected. be done. This detection result is given to the idle up device mentioned above, and is sent to the engine. When the engine speed is low, the throttle opening degree is automatically increased to prevent the engine from stopping. It is used to prevent

[0021] Note that due to the above-mentioned installation, there is a gap between the storage case 11 and the mounting hole 31 and the pressure path 30. The O-ring 17 provided around the cylindrical part of the pressure receiving spool 12 and the bottom of the mounting hole 31 and the storage case It is sealed by an annular packing 18 interposed between the gas 11 and the The leaking oil is returned to the suction side of the hydraulic pump through the return hole 32 formed in the casing 3. It is forced to flow.

[0022] In the pressure switch 1 having the above configuration, the plug nut 10 and the storage case 11 are A pressure receiving spool 12, a movable contact 14, a fixed contact 15, and It is possible to assemble the coil spring 16 in one piece. Therefore, this pressure switch 1 is Similar to the conventional pressure switch 2 shown in 2, it is installed on an appropriate test machine after assembly is completed. This has the advantage that behavioral tests can be easily conducted, and the storage space forming the storage chamber is The storage case 11 is a molded product made of thin plate material, and when fitted, the plug nut There is no risk that 10 will become larger in diameter, and it will be possible to make it much smaller than before. Also storage case The movement of the base 11 and the pressure receiving spool 12 housed therein causes the movement of the large diameter cylindrical part 11a and the small diameter cylindrical part 11a. Because it is restrained by the action of the step between it and the cylindrical part 11b, it cannot be used in the conventional pressure switch 2. The number of parts is reduced, such as eliminating the need for retaining rings 21a and 21b. Processing and assembly man-hours are reduced, such as eliminating the need for groove machining for locking rings 21a and 21b. be done.

[0023] In this example, an example of application to a hydraulic pump was explained; The pressure switch according to the invention can be used for various pressure vessels and pressure circuits such as hydraulic pressure, water pressure, pneumatic pressure, etc. Needless to say, it can be applied to roads.

[0024]

[Effect of the idea]

As detailed above, the pressure switch according to the present invention has a large diameter cylindrical portion and a small diameter cylindrical portion. The storage case that is connected to the cylindrical part is made of plate material, and one side of the large diameter cylindrical part is made of plastic. The pressure receiving spool, biasing spring, and movable contact are placed in the storage chamber formed by press-fitting and fixing into the gun nut. and fixed contacts are integrated, making it easy to conduct behavior tests after assembly. It is easy to implement, and the diameter of the plug nut can be increased by fitting the storage case. Since the degree of It is possible to reduce the size of the device, and it can be easily installed in the desired position. The movement of the pressure receiving spool in the biasing direction by the biasing spring is controlled by the small diameter cylindrical part and the large diameter cylindrical part. The spool is restrained by pressing it against the step between the Dedicated parts and associated processing and assembly are no longer required, making processing and assembly easier. This invention has excellent effects, such as reducing man-hours and reducing product costs. do.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a pressure switch according to the present invention.

FIG. 2 is a longitudinal cross-sectional view of a conventional integrated pressure switch.

[Explanation of symbols]

1 Pressure switch 10 plug nut 11 Storage case 12 Pressure receiving spool 14 Movable contact 15 Fixed contacts 16 coil spring 30 Pressure path

Claims (1)

[Scope of utility model registration request] Claim 1: A pressure receiving spool that receives the internal pressure of a pressure channel at one end and moves against the spring force of an urging spring, a movable contact fixed to the other end of the pressure receiving spool, and a movable contact fixed to the other end of the pressure receiving spool; A fixed contact is disposed inside a plug nut fixed to the end of the pressure channel, and is used to detect an excessive increase in the internal pressure by contact between both contacts as the pressure receiving spool moves. In the pressure switch, a large-diameter cylindrical part whose one side is press-fitted and fixed to the inner periphery of the plug nut and forms a storage chamber for the pressure receiving spool, the biasing spring, the movable contact, and the fixed contact is connected to the other side of the large-diameter cylindrical part. and a small-diameter cylindrical portion that fits into the pressure guiding path, the storage case is integrally formed of a plate material, and the pressure-receiving spool is moved between both cylindrical portions of the storage case by the spring force of the biasing spring. A pressure switch characterized in that it is pressed against the stepped part of.