JP2000082369A - Double action pressure switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-stage actuation type pressure switch which can operate stably for a long period through sensing of the pressure using a Hall IC without using any contacting switch, can work with a low amperage and low voltage, can sense certainly that the fluid pressure has become over the specified level, involves no risk of making unstable operation originating from vibration, and can emit output in compliance with the pressure which may appear differently. SOLUTION: A two-motion type pressure switch is composed of a diaphragm 5 receiving the fluid pressure by its one surface, an inverting plate receptacle 7 placed on the other surface of the diaphragm 5, a first inverting plate 6 installed between one surface of the receptacle 7 and the diaphragm, a second inverting plate 6 installed between the other surface of the receptacle 7 and a casing, an actuating shaft 15 whose one end is placed on the first inverting plate 6, a leaf spring 20 whose one end is fixed to the casing and to whose other end a permanent magnet 25 is fixed and to middle part the other end of the actuating shaft abuts, and a Hall IC 22 which is fixed to the casing with a certain spacing to the permanent magnet 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a room air conditioner,
A pressure switch for detecting refrigerant pressure, various oil pressures, etc. in order to control a refrigerant circuit for a car air conditioner, a brake pressure for a vehicle and an oil pump pressure, and in particular, a multi-stage operation according to a plurality of pressures. It relates to a two-action pressure switch.

[0002]

2. Description of the Related Art In a refrigerant circuit for a room air conditioner or a car air conditioner, a refrigerant pressure such as a condenser outlet pressure is detected.
Various controls are performed to perform a predetermined operation based on the signal. In a vehicle brake system, AB
Various brake controls such as S are performed, and for this purpose, the brake hydraulic pressure is detected and control is performed so that the pressure becomes a predetermined pressure. Furthermore, since it is necessary to detect the fluid pressure of gas or liquid in various fields, such as detecting the lubricating oil pressure of the engine and performing various controls of the vehicle, the diaphragm receives the pressure and detects the displacement amount of the diaphragm. Is used to detect the fluid pressure.

Various detection means have been proposed, but the displacement of the diaphragm due to fluid pressure is transmitted to an operating shaft connected to the diaphragm, and a switch is turned on and off by the operating shaft. The most common is a pressure switch that detects that the fluid pressure has exceeded a predetermined value. Since such a pressure switch operates the switch by linear displacement of the diaphragm, the operating point changes depending on the accuracy of the component itself of the switch, its mounting accuracy, and furthermore, the ambient temperature. May not be performed. Therefore, much trouble is required for quality control and the like for maintaining the accuracy.

As a countermeasure, a diaphragm which receives a fluid pressure is of a snap action type, and when the pressure of the fluid becomes a predetermined pressure or more, the diaphragm is inverted, whereby the switch is turned on and off via an operating shaft. Switches have also been proposed. According to this pressure switch, the operation of the switch is stable as compared with the above-described pressure switch, and it is possible to reduce the work for maintaining accuracy. However, each of these pressure switches controls the operation of the diaphragm via an operating shaft by the switch O.
N, OFF, the contact gradually wears out over a long period of use, and frictional powder is generated by repeated operation of the contact, which adheres to the contact surface and the surrounding dust and the like. In some cases, poor conduction at the contact portion may occur. In addition, if the battery is used for a long time, the contact resistance of the contact portion gradually changes, and the voltage of the current passing through the contact becomes large, so that the voltage on the load side may become lower than the operating voltage.

Further, in recent years, microcomputers have been frequently used in the various control devices described above, and control devices using microcomputers operate at low current and low voltage. It is preferable that the sensors operate at a low current and a low voltage for connection by simple means. On the other hand, in the conventional pressure switch, a contact-type switch is used, so that its current and voltage values are set to be relatively large in order to cope with aging at the contact portion of the contact as described above. In order to connect such a switch to a control device using a microcomputer, a common element for converting this signal into low current and low voltage is required.

[0006]

On the other hand, for example, as disclosed in Japanese Patent Application Laid-Open No. 1-124736,
Instead of a contact type switch, a magnet is fixed to the tip of an operating shaft provided on a diaphragm receiving fluid pressure, and a hole I is located at a predetermined position at a position close to a region where the magnet moves.
There has also been proposed an arrangement in which the C is disposed and the displacement of the diaphragm by a predetermined amount or more is detected by the Hall IC without contact. In this pressure detection device, it is possible to detect that the diaphragm has been displaced by a predetermined amount or more due to non-contact, and its output can be made a low current and a low voltage. In addition to the demands on component accuracy and mounting accuracy,
If such a switch is mounted on a place where there is a lot of vibration such as a vehicle, a magnetic field repeatedly approaches and separates from the Hall IC due to vibration of the diaphragm or the like, which may cause erroneous detection and hunting operation of the control device.

As a countermeasure, the present applicant has provided a reversing plate that reverses at a predetermined pressure or higher, fixes a magnet to the tip of an operating shaft that abuts the center of the reversing plate, and moves the magnet close to the moving range of the magnet. The Hall IC is provided on the fixed side of the case or the like, and the magnet is set so that it can take two predetermined positions by the operation of the reversing plate. The magnet moves from a position away from the Hall IC to a close position at a predetermined pressure or more. A pressure detection switch has been proposed in which a Hall IC detects that the operation is performed and moves in the opposite direction, and outputs a signal.

With such a pressure switch, the output of the Hall IC is clearly changed depending on whether the pressure is equal to or higher than a predetermined value. Therefore, the accuracy of the components and the mounting accuracy are not required. Can be prevented from repeatedly approaching and separating from each other to cause erroneous detection and hunting operation of the control device.

However, the pressure detection switch proposed by the present applicant can detect only one state whether the pressure is equal to or higher than a predetermined pressure. Therefore, it has not been possible to detect a plurality of pressures and generate an output, such as detecting the first predetermined pressure and the second predetermined pressure to generate an output. Therefore, for example, in a car air-conditioner,
When it is necessary to detect a plurality of pressures, for example, when performing maintenance by detecting whether the pressure is equal to or higher than a predetermined pressure or equal to or lower than a second predetermined pressure lower than the first predetermined pressure. In addition, it is necessary to provide a plurality of switches in accordance with the pressure to be detected, which leads to an increase in equipment cost and a large size.

Therefore, the present invention can operate stably for a long period of time, and can operate at low current and low voltage by detecting pressure using a Hall IC without using a contact switch. A two-stage system that reliably detects that the fluid pressure has exceeded a predetermined pressure, does not perform unstable operation due to vibration, and can generate an output according to a plurality of pressures. It is an object to provide an actuated pressure switch.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a diaphragm receiving fluid pressure on one side, a reversing plate receiver mounted on the other surface of the diaphragm, and a gap between one side of the reversing plate receiving portion and the diaphragm. A first reversing plate provided, a second reversing plate provided between the other surface of the reversing plate receiving member and the casing, an operating shaft having one end mounted on the first reversing plate, one end fixed to the casing, and a permanent end fixed to the other end. A two-acting pressure switch is composed of a leaf spring in which a magnet is fixed and the other end of the operating shaft abuts an intermediate portion, and a Hall IC fixed to a casing with a gap between permanent magnets.

Since the present invention is constructed as described above, when the fluid pressure rises and the diaphragm rises, the second reversing plate is reversed and brought close to the Hall IC, so that a predetermined output can be obtained. When the fluid pressure further rises, the first reversing plate is reversed and separates from the Hall IC to return to the original output state. When the pressure drops from this state, the reverse operation is performed.

[0013]

Embodiments of the present invention will be described with reference to the drawings. FIGS. 1 and 2 show an example in which the present invention is used as a two-acting type pressure switch. A lower end of a terminal block 3 is fitted into an upper opening of a joint 2 having a pressure inlet 1, and a square ring 4 is provided. The joint 2 and the terminal block 3 are integrated by caulking the upper end part of the joint 2 by sealing the fitting part by the above, and the casing 9 is constituted as a whole. The periphery of the diaphragm 5 is sandwiched between the lower end of the terminal block 3 and the square ring 4. A first reversing plate 6 is provided on the upper part of the diaphragm 5.
Are mounted, and a reversing plate receiver 7 is mounted thereon, and a second reversing plate 8 is further mounted thereon. A first reversing plate receiving portion 10 is provided at the center of the lower surface of the reversing plate receiving portion 7, and a protrusion 11 around the first reversing plate receiving portion 10 is in contact with the upper surface of the diaphragm 5. When the fluid pressure from the pressure inlet 1 is low, as shown in FIG. 1, the periphery of the first reversing plate 6 abuts on the periphery of the first reversing plate receiving portion 10, and the center portion is the center of the diaphragm 5. It is pressed downward in the figure.

The reversing plate receiver 7 is disposed slidably up and down on the inner wall 12 of the terminal block 3 and has a second
The central part of the reversing plate 8 is received. The periphery of the second reversing plate 8 is provided above the inner wall 12 of the terminal block 3 and is locked by the stepped portion 13. An operating shaft 15 slidably penetrates a through hole 14 provided at the center of the reversing plate receiver 7, and a lower end of the operating shaft 15 is in contact with a center position on the upper surface of the first reversing plate 6.
The second reversing plate 8 has a smaller spring constant than the first reversing plate 6, and is set such that the second reversing plate 8 is reversed with a smaller force than the first reversing plate 6.

The storage room 9 inside the terminal block 3 has a power supply V
A cc terminal 16, a power supply / output GND terminal 17, and an output OUT terminal 18 are fixed. Power supply and output GN
A leaf spring 20 is fixed to one end 19 of the D terminal 17, and a Hall IC 22 is fixed to the other end 21. The leaf spring 20 is bent in a U-shape, and a magnet holder 24 is formed at the tip thereof.
5 is fixed. The leaf spring 22 is connected to the operating shaft 15.
The permanent magnet 25 is set so as to have a predetermined positional relationship with the Hall IC 22 in this state. A terminal housing 26 is fixed to the upper center of the terminal block 3, and houses three terminals 29 in the figure from the Hall IC 22 and the like in the terminal housing 26.

When using the two-operation type pressure switch 27 configured as described above, the joint 2 is connected and fixed to an apparatus for measuring pressure via an O-ring 28. When the device is used, fluid enters through the pressure inlet 1 and pushes up the diaphragm 5 according to the pressure. At this time, the diaphragm 5 receives fluid pressure from below, and from above, the spring force of the first reversing plate 6 and the second reversing plate 8 and the force of the leaf spring 20 pressing the tip of the operating shaft 15 from above. Receiving and balancing. Therefore, as the fluid pressure increases, the first
It overcomes the pressing force of the reversing plate 6, the second reversing plate 8 and the leaf spring 20, and particularly the second reversing plate 8 and the leaf spring 2 having a small spring constant.
0 is deformed to raise the diaphragm 5, thereby raising the operating shaft 15. The positional relationship between the pressure of the fluid and the working shaft is shown in FIG. 3A. As is apparent from FIG. 3A, in the initial state where the pressure rises to the pressure A2, the second reversing plate 8 and the leaf spring 20 are mainly used. Is performed to displace.

When the pressure rises to A2 in FIG.
The operating shaft 15 rises to L1, and at this position, the second reversing plate 8
Becomes the reversal position and reverses, resulting in the state shown in FIG. This state corresponds to the pressure A2 in FIG.
Is shown as an abrupt rise curve of the operating shaft 15. Here, the operating shaft 15 pushes up the leaf spring 20 to a predetermined position, and a permanent magnet 25 provided at the tip of the leaf spring is used.
Is a position where a magnetic force for operating the Hall IC 22 is exerted, and the Hall IC generates an output by the magnetic force.

As a method of generating a signal by the output of the Hall IC, for example, a circuit as shown in FIG. 8 can be used. That is, when the two-operation pressure switch 27 is in the state shown in FIG. 1, the Hall IC 22 is turned on, and the output thereof is Hi. On the other hand, when the second reversing plate 8 of the two-operation type pressure switch 27 is in an inverted state as shown in FIG. 2, the Hall IC 22 is turned off and its output is Lo.
Becomes

When the pressure of the fluid is further increased, the operating shaft is gradually raised by pushing up the first reversing plate 6. This state is as shown in FIG.
Is shown by a diagram that rises to the right as the pressure rises. At this time, the permanent magnet 25 provided at the tip of the leaf spring
Moves upward in the figure at a position close to the Hall IC 22, the output from the Hall IC 22 maintains Lo (FIG. 2 (c)). Further, the pressure of the fluid increases,
When the reversing plate 6 is pushed up and exceeds the neutral position of the first reversing plate 6, the first reversing plate 6 is reversed, and the state shown in FIG.
This state is shown as an abrupt rise curve of the operating shaft 15 at the pressure A4 in FIG. In this state, the inversion of the first reversing plate 6 causes the operating shaft 15 to rise at a stretch, pushing up the leaf spring 20, thereby pushing up the permanent magnet 25, and the permanent magnet 25 comes out of the magnetic force sensing range of the Hall IC. IC22 turns on again,
The output becomes Hi.

When the pressure decreases from this state, the operation reverse to the above operation is performed. That is, when the pressure becomes A3 lower than A4 due to the hysteresis of the leaf spring, the first reversing plate 6 is reversed downward, and the output from the Hall IC 22 changes from Hi to Lo. When the pressure further decreases, the operating shaft 15 gradually drops, but its output maintains Lo. This state is shown in FIG. 3A by a diagram that becomes lower left as the pressure decreases from the pressure A3 to the pressure A1. Further, the pressure of the fluid is lowered, and A is lower than A2.
When it reaches 1, the second reversing plate 8 is reversed. This state is shown in FIG.
In (a), it is shown as a sudden drop curve of the operating shaft at the pressure A1. As a result, the permanent magnet 25 at the tip of the leaf spring 20 is out of the magnetic force sensing range of the Hall IC 22, so that the output from the Hall IC 22 changes from Lo to Hi. Since these output signals are low voltage, they can be directly input to the microcomputer to perform predetermined automatic control. Further, the above operation can be shown in FIG. 3B when the relationship between the fluid pressure and the output of the Hall IC is viewed, and when the relationship between the output of the Hall IC and the position of the operating shaft is viewed in FIG.
It can be shown as follows.

The two-acting pressure switch 27 shown in FIG.
Since the operation is performed as described above, for example, in a car air conditioner, it is detected whether the refrigerant pressure is equal to or higher than a first predetermined pressure or equal to or higher than a second predetermined pressure lower than the first predetermined pressure. For example, when the maintenance is performed, the reversing pressure of the second reversing plate 8 is set when the refrigerant pressure is the second predetermined pressure, and the reversing pressure of the first reversing plate 6 is set to the second pressure. By setting when the first predetermined pressure is higher than the second predetermined pressure, the Hall IC is switched to Hi.
When a signal is issued, it can be used to determine that the refrigerant pressure of the car air conditioner is too high or too low and requires maintenance.

In the two-acting pressure switch 27, the distance D1 between the centers of the two Hi and Lo of the Hall IC 22 and the distance D2 between the centers of the snap action curves of the first and second reversing plates are determined. Although it is necessary to make them equal, it can be coped with by adjusting the distance between the permanent magnet and the Hall IC. FIG. 4 shows the relationship between the moving direction of the permanent magnet and the output of the Hall IC.
FIG. 9 shows a state in which the distance B between the permanent magnet and the Hall IC is changed. In this figure, the positions of the Hall IC and the permanent magnet are shifted from the center as shown in FIGS. 5A and 5B, and the S pole of the permanent magnet is positioned closer to the center of the Hall IC. I have. Thus, the permanent magnet and the Hall I
It is preferable that the terminal block has an adjusting portion for adjusting the distance between the switch C and the arrangement relationship between the poles of the permanent magnets and the Hall IC. However, when the switch is designed and assembled, it is adjusted to have predetermined characteristics. It can also be manufactured. In FIG. 4, the switching portion of the output signal when the movement of the permanent magnet is small is the operation when the permanent magnet is located below the Hall IC, and the switching portion of the output signal when the movement of the permanent magnet is large. Is the operation when the permanent magnet is above the Hall IC.

As is apparent from FIG. 4, the operating characteristics of the above arrangement are as follows. Assuming that the distance between the intermediate positions of the hysteresis of the output signal position is D3, this distance D3 is determined by the distance between the permanent magnet and the Hall IC. It can be seen that the distance D3 changes and the distance D3 increases as the interval decreases. Also,
It can be seen that when the permanent magnet is close to the Hall IC, the hysteresis of the Hi and Lo outputs increases at each switching position, and if the interval is longer than a predetermined value, the Hi and Lo switching output cannot be obtained.

On the other hand, FIG. 6 shows a characteristic diagram when the magnets are arranged as shown in FIG. That is, in this arrangement, the S pole of the magnet is arranged so as to face the Hall IC. Thus, when the installation direction of the magnet is changed, the distance between the magnet and the Hall IC is increased from small to large. It can be seen that the distance between the centers of Hi and Lo gradually widens halfway when going, and the distance decreases as the distance increases. The hysteresis of the Hi and Lo outputs at this time increases as the distance increases, and the switching output is not finally obtained as in FIG.

[0025]

Since the present invention is constructed and operates as described above, the present invention operates stably for a long period of time by detecting pressure using a Hall IC without using a contact-type switch.・ It can be operated at low voltage, and reliably detects that the fluid pressure has exceeded a predetermined value, and does not perform unstable operation due to vibration, and outputs according to multiple pressures Can occur.

[Brief description of the drawings]

1A and 1B show a first embodiment of the present invention, wherein FIG. 1A is a first sectional view, FIG. 1B is a second sectional view perpendicular to the first sectional view,
(C) is a plan view.

FIG. 2 is an explanatory view of the operation of the first embodiment, wherein (a) to (d) show the operation when the pressure of the fluid increases in order.

FIG. 3 shows an operation characteristic diagram of the first embodiment of the present invention,
(A) is a pressure-axis position change graph, (B) is a pressure-output diagram, and (C) is an axis position-output diagram.

FIG. 4 is a movement-output diagram of the magnet when the permanent magnet and the Hall IC of the present invention are arranged in the first mode and the interval is changed.

5A and 5B are views for explaining the arrangement of the permanent magnet and the Hall IC in FIG. 4, wherein FIG. 5A is a perspective view thereof and FIG. 5B is a plan view thereof.

FIG. 6 is a movement-output diagram of the magnet when the permanent magnet and the Hall IC of the present invention are arranged in the second mode and the distance between the permanent magnet and the Hall IC is changed.

FIG. 7 is a perspective view illustrating the arrangement of the permanent magnet and the Hall IC in FIG. 6;

FIG. 8 is a circuit schematic diagram showing an example of a Hall IC circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure introduction port 2 Joint 3 Terminal block 4 Square ring 5 Diaphragm 6 1st reversing plate 7 Reversing plate receiver 8 2nd reversing plate 10 1st reversing plate receiving part 11 Projection part 12 Inner wall 13 Step part 14 Through-hole 15 Working shaft 16 Vcc terminal 17 GND terminal 18 OUT terminal 20 Leaf spring 21 Leaf spring mounting arm 22 Hall IC 23 Support arm 24 Magnet holder 25 Permanent magnet 26 Terminal storage part 29 Terminal

Claims (5)

[Claims] 1. A diaphragm receiving fluid pressure on one side, a reversing plate receiver mounted on the other surface of the diaphragm, a first reversing plate provided between one side of the reversing plate receiving portion and the diaphragm, and the other surface of the reversing plate receiving portion. A second reversing plate provided between the casings, an operating shaft having one end mounted on the first reversing plate, one end fixed to the casing and a permanent magnet fixed to the other end, and the other end of the operating shaft fixed to an intermediate portion And a Hall IC fixed to the casing with a gap between the leaf spring and the permanent magnet. 2. The two-acting pressure as claimed in claim 1, wherein the permanent magnet approaches the Hall IC when the second reversing plate is reversed, and the permanent magnet moves away from the Hall IC when the first reversing plate is reversed. switch. 3. The two-acting pressure switch according to claim 1, further comprising an adjustment unit for adjusting the distance between the permanent magnet and the Hall IC. 4. The two-acting pressure switch according to claim 1, wherein the center of the Hall IC and the arrangement of the permanent magnet are shifted, and the S pole of the permanent magnet is arranged on the side closer to the center of the Hall IC. . 5. The two-acting pressure switch according to claim 1, wherein the S pole of the magnet is arranged so as to face the Hall IC.