JPS60119041A - Pressure detector using one lead switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention detects the fluid pressure of fluid such as gas or liquid flowing into and out of a sealed area, and controls this fluid pressure so that it is within a preset tolerance value. The present invention relates to a pressure detector that is effective for use in the device.

Conventionally, various examples of devices have been known as devices that detect the pressure of fluid and control it so that the pressure is within an appropriate range. (8-day OD) will be explained using an actuator used for the 8-day OD. That is, in the same figure, 1 is a DC motor,
The piston 3 is reciprocated by 20 rotations of the crankshaft, and the atmosphere flowing in from the intake port 4 is sent into the positive pressure chamber 6 based on the operation of the pump 5. The main chamber 6 is equipped with a pressure detector 7, which will be described later, as well as an electromagnetic valve 8 with a solenoid. On the other hand, an actuator chamber 9 is provided adjacent to the positive pressure chamber 6, and a diaphragm 11 that operates based on positive pressure supplied from the intake port 1o is fitted therein. Furthermore, a pull rod 12 is fixed to the approximate center of the diaphragm 11, and the sol rod 12 is connected to a wire 14. The wire 14 is supported by a wire guide 15 and is driven in tension. A cover 16 is fixed integrally with the bracket 17.

A resilient member 18 is installed in the actuator chamber 9, and a force is applied to push back the diaphragm lli against the positive pressure. 19 is an intake boat of the solenoid valve 8, 2° is also a supply boat), and 21 is an exhaust boat. 22 is a breathing port of the actuator chamber 9.

Further, the pressure detector 7 has a built-in diaphragm 23 which operates under positive pressure, and a rod 2 connected to the diaphragm 23.
4 is pivotally supported so as to be movable in the left and right direction. In order to limit the range of movement of the rod 24, two microswitches (not shown) are disposed at the upper and lower limits in close proximity to the rod, and are configured to connect and disconnect in response to the movement of the rod 24. has been done.

The operation mode of the actuator shown in the above embodiment is as follows. That is, if the pressure detector 7 indicates that the atmospheric pressure in the positive pressure chamber 6 is below the allowable value, the DC motor 1 automatically starts rotating, and the pump connected to the piston 3 reciprocates by the operation of the crank 2. 5, atmospheric air is supplied into the positive pressure chamber 6, and when the positive pressure chamber 6 reaches a predetermined high pressure and the pressure detector 7 determines that the atmospheric pressure is above a permissible value, the motor automatically stops. While the vehicle is running in this state, if the vehicle speed decreases beyond the preset constant speed state, the solenoid-equipped solenoid valve 8 disposed in the main royal palace 6 is activated.
The intake boat 19 occupies the position shown in the figure. Pressure air flows into the actuator chamber 9 through the supply boat and the intake port 10. Accordingly, the diaphragm 11 moves in the direction indicated by the diaphragm 11', that is, to the right in the drawing, and similarly pulls the wire 14t connected to the pull rod 12 to the right. The other end of this wire 14 is connected to a throttle valve opening adjustment device (not shown), and the above operation increases the opening of the throttle valve, increases the vehicle speed from a decrease, and brings the vehicle to a constant speed state. It can be returned.

In the above description, the operation mode of the pressure detector 7 that detects the atmospheric pressure in the positive pressure chamber 6 and controls the motor is as follows. That is, the rod 24 connected to the diaphragm moves from side to side in response to the action shown in the schematic view of the main part in FIG. This rod 24 is provided with a protrusion 25, and microswitches 26 and 27 are attached to one side of the cylinder, and are turned on and off when the protrusion 25 comes into contact with the rod. The mouse is a control circuit, and an example of its configuration is shown in FIG. That is, normally open switch 2
6a, a normally closed switch 27a, a relay R9 and a switch R1+R1 opened and closed by the relay R, and a DC motor M.
It consists of a power supply B. Now, when the air pressure inside the main royal room 6 decreases, the rod 24 moves to the right, and the normally open switch 2
6. When a is turned on, the relay R is activated to conduct the switches Rs+Rze and rotate the DC motor Mi. In this state, when the atmospheric pressure in the positive pressure chamber 6 reaches a predetermined high pressure, the rod 24 moves to the left, and the normally closed switch 27 a f
By turning off the relay, the operation of the relay is stopped, the switch R is turned off, and the driving of the DC motor M is stopped.

In this way, the conventional pressure sensor uses the diaphragm n and the spring 51 to convert pressure fluctuations into the movement of the rod 24, and uses a microswitch that turns on and off in response to the movement of the rod to determine the upper limit of the allowable pressure and the Since the lower limit was controlled, the mechanism was complicated and the cost was high. That is, the circuit example shown in FIG. 3 requires two microswitches, one relay, and two switches, which has the drawback of increasing the size of the entire device.

On the other hand, a method has also been considered that uses only one microswitch instead of the pressure switch to perform two-position control of the rod stroke. The main purpose of this method is to take advantage of the hysteresis characteristic of the plate spring by receiving the movement of the rod by a plate and bringing it into contact with the micro-contact.

That is, as shown in FIG. 4, two positions are detected using a leaf spring that causes hysteresis as shown in D at the operating point associated with the movement of the rod stroke. Based on the variation in the leaf spring characteristics, The contact force of the contact point differs from device to device, and it has the disadvantage that it cannot follow the drastic changes in the air pressure inside the main chamber.

The present invention has been made for the purpose of solving the above-mentioned drawbacks of conventional fluid pressure detectors and providing a pressure detector having a simple structure and stable operation. Another object of the present invention is to provide a pressure sensor that has fewer elements constituting the device, is smaller in size, and is inexpensive. In order to achieve the above object, the present invention converts the pressure change in the positive pressure chamber into the movement of a rod, and a magnet is attached to one end of the piston fixed to the rod, and the magnet is placed close to the magnet. The main purpose of this invention is to obtain a pressure detector characterized by consisting of a single reed switch that opens and closes in response to the movement of a magnet.

The present invention will be described in detail below based on the drawings.

That is, FIG. 5 is a sectional view showing a pressure detector based on the present invention, in which reference numerals 31 denote the first pressure chamber 52 (in the embodiment c, the main chamber) and the second pressure chamber 53 (in this embodiment, the atmospheric pressure A wall section 54 is formed in the wall section 31 to separate the room from the room.
A diaphragm 32 is provided to cover the positive pressure chamber 5.
It is designed to respond to changes in the air pressure inside 2. The wings are rods, one end of which is in contact with the diaphragm 32, the other end of which extends toward the atmospheric pressure chamber 53, and a piston is integrally provided in the middle of the rod. It is. A magnet 35 is attached to one end of the piston 34, and a reed switch 37 is disposed in a concave circle on the side wall adjacent to the magnet. A is a rod that limits the movement and is an adjuster for setting pressure, and is located between this adjuster 3B and the piston 74.

A spring 39 is interposed to urge the rod 33 toward the diaphragm 32. Also, cut the lead wires led out from both ends of the lead switch 37.

The wire extends to the atmospheric pressure chamber side and is connected to the wiring printed circuit board core.

The magnetic characteristics of the reed switch 37 having the above configuration will be explained below. That is, when the magnet part moves in the Y direction with respect to the reed switch 37 as shown in FIG. 6(A), the 0N-OFF state of the reed switch 37 will be the ON region and HOLD between On areas
It is known that there are areas.

This HOLD area is the state (a) shown in the figure (01),
That is, this is a region in which the OFF state is maintained when transitioning from OFF to ON, and the ON state is maintained when transitioning from state (b), ie, ON to OFF. In other words, the HOLD region can be said to be a hysteresis region of the reed switch 37. Therefore, a major feature of the embodiment of the present invention shown in FIG. 5 is that the hysteresis region of the reed switch J is utilized to limit the movement range of the rod blade.

FIG. 7 shows an example of a control circuit when the present invention is used.

That is, it is composed of a reed switch 37, a relay R, a switch Ra that is opened and closed by the relay R, a DC motor M, and a power source B. The operation of the present invention will be described below based on the present control circuit example and the above-mentioned embodiments.

Now, assuming that the air pressure on the main chamber side is within the preset tolerance range, the magnet 35 fixed to the piston 34 is in the OFF region shown in FIG. 6(c),
Since the IJ-doswitch calculation is "off", the DC motor M is stopped. Next, as the actuator operates, the air pressure on the main royal side gradually decreases, and the elastic force of the spring moves the piston U to the right, as shown in Figure 6 (
The magnet words also move to the right as shown in Figure 6 (0).
) when the reed switch 37 reaches the ON region shown in
As a result, relay Rt'' is activated, switch Ra is turned on, and DC motor M starts rotating.In this way, the air pressure inside the main royal chamber increases, and as shown in Fig. 6, the diaphragm 32 is pushed by atmospheric pressure and moves to the left.

When the upper limit is reached, the magnet) 35 is turned on again as shown in Fig. 6 (
0) is turned on to stop the rotation of the DC motor M, and the atmospheric pressure in the positive pressure chamber stops at the upper limit. When the reed switch 370 is turned on and off as described above, the reed switch 37 (magnet) 35
Based on the relative positional relationship between It is possible to set.

In the case of this embodiment, as shown in FIG. 6(0), (a) the reed switch 37 is turned on from OFF at the magnet position eY+, and (b) the reed switch 37 is turned on.
Assuming the position of the magnet that turns off from t" Y s, there is a clear difference in the positional relationship between %Y1 and Y2, and the moving range of the magnet word corresponding to this different length is the atmospheric pressure in the main room. This is a factor that determines the upper limit and the lower limit of atmospheric pressure.Specifically, the magnet 35 is
When the magnet x reaches the position Y2, the air pressure inside the main royal room reaches the lower limit, and when the magnet x reaches the position Y2, the air pressure inside the main room reaches the upper limit.

The embodiments and operation modes of the pressure detector using one reed switch according to the present invention will be explained in Figure 9, which is shown in FIG. The metal bellows 43t- may be configured to be expanded or contracted in response to changes in the air pressure on the front royal side by using the metal bellows 43t-. In this case, because of the spring action of the metal bellows, the spring can be omitted. Furthermore, instead of the above structure, an opening is formed in the wall separating the main chamber and the atmospheric pressure chamber, and an airtight sealing member such as an O-ring, packing, oil seal, etc. is installed, and the rod is connected to the airtight sealing member. The rod can be formed so that it can be moved by pressure that penetrates the member while being in close contact with the member, and can also be moved in the opposite direction by, for example,
not.

FIG. 9 shows another further improved embodiment of the present invention, in which the same components as in the embodiment shown in FIG. 5 are denoted by the same numbers. This embodiment is characterized by a magnet fixed to the piston 34 and a magnetic path guide 44 made of a ferromagnetic material fixed to the magnet.

II] As shown in FIG. 10, the reed switch 37 operates when the magnet 35 approaches and the magnetic flux in the sensitive part of the reed switch 37 reaches a certain value or higher, and normally The operating state is determined by a factor called emotion value. However, since the magnet has a three-dimensional magnetic field, its strength distribution, or magnetic flux density, is
As the distance from the magnet increases, it becomes diluted,
Furthermore, as shown in the figure, there is a property that the leakage magnetic flux which is not involved in the operation of the reed switch is large. For this reason, in devices where the close distance between the reed switch and the magnet is limited, there is a drawback that all magnets with large magnetic force, that is, large surface magnetic flux density, must be used. By providing the magnetic path guide 44 as in this embodiment, the magnetic path is attracted to the tip of the magnetic path guide 44 as shown in FIG. 11, resulting in the effect of increasing the total magnetic flux density in the vicinity of the magnetic path guide. is demonstrated. In addition, since the magnetic field, which conventionally spread three-dimensionally, can be concentrated on the reed switch 37, the reed switch exhibits high ON-OFF characteristics and stable operation. Therefore, the distance between the reed switch and the magnet is limited in advance. 6
1) Good results can be obtained without using expensive magnets with a strong surface magnetic flux density in devices that cannot be accessed.

In addition, assembly has the advantage that later variations in emotional value among devices are reduced.

The structure and operation of the pressure detector according to the present invention have been described in detail above based on the embodiments. According to the present invention, various advantages and effects described below are achieved. That is, instead of the conventional method of controlling the microswitch using two microswitches, it is now possible to detect two positions at the upper and lower limits of pressure by combining only one reed switch and a magnet. , the control circuit has the advantage of being extremely simple. Therefore, the effect of reducing manufacturing costs and man-hours is significant. In addition, since two-position control is performed by utilizing the hysteresis characteristic that reed switches naturally have, there is no need to add new parts, and it can be easily assembled using only conventional products. It has the advantage of being colored. Furthermore, when installing a reed switch, the off point of the reed switch can be set to match the upper limit pressure position, so the operating point is stable and there is no variation between devices. It has the effect of quickly tracking even when there are severe changes in atmospheric pressure. In addition, by providing a magnetic path guide to the magnet, the magnetic field can be concentrated, which has the effect of making the operation of the reed switch more stable. Combined with the above six types of effects, it is possible to concentrate the magnetic field. The present invention can be applied to pressure detectors that control fluid pressure in a certain manner to bring about great effects.

In the above embodiment, a positive pressure pressure sensor was described, but there is a negative pressure in the first pressure chamber containing a spring. ! It goes without saying that this device can also be used as a negative pressure detector by opening the adjacent second pressure chamber to the atmosphere.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of an automatic speed control device for an automobile, Fig. 2 is a schematic diagram of main parts showing a conventional pressure detector, and Fig. 3 is a circuit diagram showing a control means of the device shown in Fig. 2. , FIG. 4 is a graph showing the operating mode of a two-position detection device using a conventional leaf spring, and FIG. 5 is a sectional view showing a pressure detector according to the present invention.
6(A)(B)(0) are explanatory diagrams showing the magnetic characteristics of the reed switch, FIG. 7 is a circuit diagram showing the control means of the device shown in FIG. 5, and FIG. 8 is an explanatory diagram showing the magnetic characteristics of the reed switch. 9 is a sectional view showing a further improved embodiment of the present invention, FIG. 10 is an explanatory diagram showing the magnetic flux distribution of a normal magnet, and FIG. 11 is a sectional view showing another improved embodiment of the present invention. FIG. 3 is an explanatory diagram showing the magnetic flux distribution of the magnet based on the example shown in FIG. 31...Wall portion, 32...Diaphragm, 33...
÷Kurajyurotsud% Dictionary... Piston, Audience... Magnet, 36... Side wall, Bellows, 44... Magnetic guide, 52... First pressure chamber, 53... Second pressure chamber , situation...opening. Fig. 2 Fig. 3 10 - Stroke - Fig. 5 Y2 Y. Figure 7 Figure 8 Figure 9 Figure 110 Figure 11

Claims (8)

[Claims] (1) In a pressure detector used in a fluid pressure control device that detects changes in fluid pressure and controls the pressure so that it is within a preset tolerance range, a first pressure chamber into which the fluid flows in and out. a second pressure chamber adjacent to the first pressure chamber; an opening formed in a wall completely separating the first pressure chamber and the second pressure chamber; and a diaphragm attached to the opening. a rod having one end in close contact with the diaphragm and the other end extending toward the first pressure chamber side or the second pressure chamber side; a piston formed integrally with the rod; and a piston configured to press the rod against the diaphragm side. a biased spring, a magnet attached to one end of the piston, and a device disposed close to the magnet that opens and closes in response to movement of the magnet.
A pressure detector using a single reed switch, characterized in that it consists of a reed switch. (2) A patent in which the first pressure chamber is a main chamber, the second pressure chamber is an atmospheric pressure chamber, and the other end of the rod is in close contact with the diaphragm and extends toward the atmospheric pressure chamber. A pressure detector using one reed switch according to claim 1. (3) The first pressure chamber is a negative pressure chamber, the second pressure chamber is an atmospheric pressure chamber, and one end of the rod is in close contact with the diaphragm, and the other end is extended toward the negative pressure chamber side. A pressure detector using one reed switch according to claim 1. (4) Pressure using one reed switch according to claim 2 or 3, characterized in that a magnetic path guide made of a ferromagnetic material is derived from a magnet fixed to one end of the piston. Detector. (5) In a pressure detector used in a fluid pressure control device that detects changes in fluid pressure and controls the pressure so that it is within a preset tolerance range, a first pressure chamber into which the fluid flows in and out. a second pressure chamber adjacent to the first pressure chamber; an opening formed in a wall separating the first pressure chamber and the second pressure chamber; and a telescopic chamber attached to the opening. a bellows, a rod fixed to interlock with the bellows and having the other end extending toward the first pressure chamber side or the second pressure chamber side, a piston formed integrally with the rod, and a second piston attached to one end of the piston. The attached magnet and the magnet are placed close to each other,
A pressure detector using a single reed switch, characterized in that it consists of a single reed switch that opens and closes in response to the movement of a magnet. (6) The first pressure chamber is a positive pressure chamber, and the second pressure chamber is an atmospheric pressure chamber, and the other end of the rod fixed to interlock with the bellows extends toward the atmospheric pressure chamber. A pressure detector using one reed switch according to claim 5, which has a configuration as follows. (7) The first pressure chamber is a negative pressure chamber, and the second pressure chamber is an atmospheric pressure chamber, and the other end of the rod fixed to interlock with the bellows extends toward the negative pressure chamber. A pressure detector using one reed switch according to claim 5, which has a configuration as follows. (8) Magnet piece 5 fixed to one end of the piston
A pressure detector using one reed switch according to claim 6 or 7, characterized in that a magnetic path guide made of a ferromagnetic material is derived.