JP2600540Y2 - pressure switch - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure switch which is electrically turned on and off in response to a change in the pressure of a fluid upon receiving the pressure of the fluid.

[0002]

2. Description of the Related Art In general, a pressure switch has a diaphragm for receiving the pressure of a fluid, and a central portion normally protrudes from a peripheral portion to the front side, and when a force exceeding a certain level is applied in a direction to depress the protruding state, the central portion is turned on. Conversely, a reversing disk that reverses so as to protrude to the back, and an electric switch that is electrically turned on and off by the reversing operation of the reversing disk, has a pressure change applied to the diaphragm,
The switching means is turned on and off by reversing the reversing disk.

Conventionally, a reversing disk used for such a pressure switch has been formed in a relatively simple dish shape having no breaks as shown in FIG.

However, in the above-mentioned simple dish-shaped reversing disk, the amount of displacement at the time of reversing cannot be made as large as desired, so that the on / off timing of the switch does not always go as planned, and There is a disadvantage that a large number of man-hours are required for time adjustment.

Conventionally, as shown in FIG. 9, for example, a reversing plate 101 is formed by forming an annular portion 101a forming a peripheral edge.
And an arm-like portion 101c extending toward the center from the annular portion 101a and serving as a free end in the central portion 101b.

[0006]

[0007] However, as shown by the broken line in FIG. 7, the reversing board as described above has a reversing load when the load is applied to the reversing board and when the load is reduced. (Load differential), the difference between the load at which the pressure switch is turned on from off and the load at which the pressure switch is turned on from off (operating differential) was large, and precise operating characteristics could not be obtained.

Accordingly, an object of the present invention is to provide a pressure switch which has a small hysteresis and can obtain precise operating characteristics.

[0008]

In order to achieve the above object, a pressure switch according to the present invention has a diaphragm for receiving the pressure of a fluid, and normally a central portion protrudes from a peripheral portion to a front side to depress the protruding state. A disc spring that deforms so that the central portion protrudes backward when a force of a certain degree or more is applied in the direction, and switching means that is electrically turned on and off by the deformation of the disc spring. In a pressure switch in which the disc spring is deformed by a change in the pressure applied to the diaphragm to turn on and off the switching means, the disc spring is moved from the central annular portion to the peripheral edge from the annular portion. It is characterized in that it is formed by a plurality of arm portions that extend and become free ends at the peripheral portion.

[0009]

[Action] The disc spring is continuously connected at the center annular portion, but the peripheral portion is a free end of the arm-shaped portion.
When a load is applied in the middle of the arm and when the load is reduced, the disc spring does not perform a sudden reversing operation, and the hysteresis operation is small.

[0010]

An embodiment will be described with reference to the drawings. FIG.
FIG. 3 is a front sectional view of the operation type pressure switch.

Reference numeral 1 denotes a lower housing molded from a synthetic resin. Reference numeral 2 denotes an upper housing having a pressure introduction port 2a formed in the center of the upper end, and components constituting a two-operation type pressure switch are accommodated in the housings 1 and 2.

An electric switch 3 using a leaf spring 31 is provided at the bottom of the lower housing 1.
A movable contact 32 is attached to the distal end of the leaf spring 31, and a fixed contact 33 is attached to the lower housing 1 side to face the movable contact 32. Leaf spring 31
Are biased in a direction to press the movable contact 32 against the fixed contact 33.

A pair of terminals 34, 35 disposed through the bottom of the lower housing 1 are fixed to the bottom of the lower housing 1, and the base of the leaf spring 31 is fixed to one of the terminals 34, and the fixed contact 33 is the other terminal 35
It is stuck to. Therefore, when the movable contact 32 and the fixed contact 33 are closed and opened, the terminals 34 and 35 are electrically connected and disconnected, and the electric switch 3 is turned on and off.

Reference numeral 4 denotes an operating rod for turning on and off the electric switch 3 by pushing a central portion of the leaf spring 31 against its urging force. The operation rod 4 has a step portion 4a formed in the middle thereof, and the head side is formed thin.

Reference numeral 5 denotes a cylindrical operating rod guide for guiding the operating rod 4. The operating rod 4 is loosely fitted in the operating rod guide portion 5 and is slidably provided in the axial direction. The operating rod guide portion 5 is formed integrally with the lower housing 1 and is formed simultaneously when the lower housing 1 is molded. The operating rod guide 5 is not completely cylindrical, but is notched with a width necessary for mounting the leaf spring 31 and the like.

A diaphragm 6 made of a flexible thin film which is displaced by receiving the pressure P of the fluid in the pressure inlet 2a is sandwiched and fixed between the housings 1 and 2. 7 is an O-ring for sealing.

Inside the diaphragm 6, there are first and second
Are disposed on the lower surface side and the upper surface side of the support wheel 13. As shown in FIG. 1, the first disc spring 11 includes a central annular portion 11a, and six arm-shaped portions 11b extending outward from the annular portion 11a at intervals of, for example, 60 degrees from the annular portion 11a. And each arm-shaped portion 11b is a free end at the peripheral edge.

As shown in FIGS. 2 and 3, the first disc spring 11 has a central portion 11a projecting downward (front side) from the peripheral portion, that is, toward the electric switch 3 in a normal state where no external force is applied. It is formed in a shape.

The center portion 11a of the first disc spring 11
When a pressing force is applied in the middle of the arm-shaped portion 11b in the direction to depress the central portion 11a, the central portion 11a is displaced little by little according to the pressing force at that time, as shown by a solid line in FIG. When it reaches, it is greatly deformed, and the central part 11a is upward (back side).
Displaced so as to protrude.

As described above, the periphery of each arm 11b of the first disc spring 11 is a free end. Therefore, when a load is applied in the middle of the arm-shaped portion 11b and when the load is reduced, the first disc spring 11 does not perform a sudden reversing operation and operates with a small load differential. As a result, the operating differential of the electric switch 3 is also small.

Returning to FIGS. 2 and 3, the second disc spring 12
Is formed in a dish shape whose central portion protrudes upward (toward the diaphragm 6). In addition, the first disc spring 11 is
, And the second disc spring 12 is arranged to face the upper end surface of the operating rod 4.

The first disc spring 11 has a central annular portion 11a.
Has an upper surface abutting against the support wheel 13 on the upper surface side, and a lower surface slightly inside the lower surface is supported by an annular bead 14.

Therefore, the support wheel 13 is connected to the diaphragm 6
When the first disc spring 11 is displaced by being pushed from the side, as shown in FIG. . Then, when the pressing force applied to the first disc spring 11 reaches a certain value, the first disc spring 11 reverses, and the central annular portion 11a is displaced in a direction approaching the diaphragm 6.

As a result, the operating rod 4 is moved to the leaf spring 3
The movable contact 32 is pushed and moved by the
3, the electric switch 3 is turned on as shown in FIG.

At this time, the support wheel 13 and the lower housing 1
Means that the support wheel 13 does not move further back. As shown in FIG. 3, the lower housing 1 and the support wheel 13 are formed with concave and convex portions 1a and 13a which engage with each other, and serve as positioning and rotation stop.

An annular bead 14 for supporting the lower surface of the first disc spring 11 is formed integrally with the lower housing 1 and is formed at the same time as the lower housing 1 is molded. Note that the bead 14 is not a continuous ring, but is cut out with a width necessary for mounting the leaf spring 31 and the like.

The second disc spring 12 is arranged so as to be in close contact with the back surface of the diaphragm 6, and its outer edge is in contact with the support wheel 13. Therefore, the support wheel 13 is pushed and displaced by the force applied from the diaphragm 6 to the second disc spring 12. However, the second Belleville spring 12 is thicker than the first Belleville spring 11 and does not deform unless a large force is applied compared to the first Belleville spring 11.

Accordingly, when a larger force is applied to the second disc spring 12 from the diaphragm 6 after the first disc spring 11 is deformed and the support wheel 13 cannot move to the rear side, as shown in FIG. As a result, the second disc spring 12 is deformed, and its central portion is displaced in a direction away from the diaphragm 6. Then, the operating rod 4 is pushed by the second disc spring 12 to push the leaf spring 31, the movable contact 32 is separated from the fixed contact 33, and the electric switch 3 is turned off.

The pressure switch of this embodiment is used, for example, by being attached to the high pressure side of a refrigeration cycle of a vehicle cooling system. The pressure P of the refrigerant at the pressure inlet 2a
2 and FIG. 3, the first and second disc springs 11 and 12 are not inverted, and the leaf spring 31 is pressed by the first disc spring 11, The electric switch 3 is off.

When the refrigerant pressure P at the pressure inlet 2a increases, the support wheel 13 and the second disc spring 12
, And move integrally. Then, the center portion of the first disc spring 11 is consequently reversed.
When the pressure P reaches an appropriate pressure equal to or higher than a predetermined value, the first disc spring 11 is inverted to the state shown in FIG. 4, and the electric switch 3 is turned on.

At this time, since the reverse displacement amount of the first disc spring 11 is sufficiently large, when the first disc spring 11 is reversed, the operating rod 4 largely moves, and the electric switch 3 is moved.
Performs on / off operation reliably.

Then, the pressure P further increases, and the pressure P
When the pressure exceeds the appropriate pressure, as shown in FIG. 5, the second disc spring 12 is reversed and the operating rod 4 is pushed, and the movable contact 32 is moved.
Is off from the fixed contact 33. Then, even if the pressure P further increases, the state of FIG. 5 does not change. If the pressure P decreases, the state returns to the original state by an operation reverse to that at the time of the increase.

Therefore, when the pressure P at the pressure inlet 2a is within an appropriate range, the contact is turned on, and when the pressure P is too low and too high, the contact is turned off. In addition,
The present invention is not limited to the above embodiment, and the disc spring 11 may be formed in a shape in which the arm-shaped portion 11b is not straight but bent as shown in FIG. 6, for example.

The present invention can also be applied to, for example, a three-acting pressure switch other than the two-acting pressure switch. In this case, the present invention is applied to a plurality of disc springs in one pressure switch. Is also good.

[0035]

According to the pressure switch of the present invention, the disc spring is connected continuously at the center annular portion, but the peripheral edge is the free end of the arm, so that the disc spring is abrupt. The reversing operation is not performed, and as a result, the load differential is small, and therefore, the operating differential of the switching means is small, and precise operating characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a disc spring according to an embodiment.

FIG. 2 is a side sectional view of the embodiment.

FIG. 3 is a front sectional view of the embodiment.

FIG. 4 is a front sectional view of the embodiment in a state in which the pressure reception is increased.

FIG. 5 is a front sectional view of the embodiment in a state where the pressure reception is increased.

FIG. 6 is a plan view of another embodiment of the disc spring.

FIG. 7 is a displacement amount characteristic diagram of a disc spring.

FIG. 8 is a perspective view showing a part of a conventional reversing disk cut away.

FIG. 9 is a perspective view of another conventional reversing disk.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Electric switch 6 Diaphragm 11 1st disc spring 11a Annular part 11b Arm-shaped part

Claims (1)

(57) [Scope of request for utility model registration] 1. A diaphragm for receiving a pressure of a fluid, and in a normal state, a central portion protrudes from a peripheral portion to a front side, and when a force more than a certain level is applied in a direction to depress the protruding state, the central portion conversely protrudes to a rear side. And a switching means that is electrically turned on and off by the deformation of the disc spring. The disc spring is deformed by a change in the pressure applied to the diaphragm to change the switching means. In a pressure switch that is turned on and off, the disc spring is formed by a central annular portion and a plurality of arm-shaped portions extending from the annular portion toward the periphery and forming free ends at the periphery. A pressure switch, characterized in that: