JPH0367419A - Switch - Google Patents

Abstract

PURPOSE:To miniaturize a vacuum switch and make it lightweight by rotating a driving lever with the expansion by the vertical displacement effect of a piezoelectric element, holding its position with a holding means, moving a driving means with the holding means to return the driving lever. CONSTITUTION:When the voltage with the preset polarity is applied to a piezoelectric element 29, the element 29 is quickly extended, a driving lever 12 is rotated clockwise against a spring 16, a conductor 1c is pushed up via a spring 10 and an insulating rod 9A, and contact points 1B and 1A are closely stuck. A latch lever 30 is rotated counterclockwise by a spring 35 into a vertical position, it collides with a piezoelectric element 36 and is stopped, and the lever 12 is held by a roller 30B in the closed state. The DC voltage is applied to the piezoelectric element 36 to extend it, the latch lever 30 is rotated in the arrow D direction, the driving lever 12 is opened, and contact points 1A and 1B are dissociated by the exciting force of the spring 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to means for applying a switching driving force to the contacts of a vacuum switch.

[Prior Art] FIG. 2(a) shows the state of a conventional vacuum switch when it is closed. In the figure, a fixed contact IA and a movable contact 1B provided at the tip of a conductor 1c are built into a vacuum switch tube 1 which is evacuated. The conductor IC is held by a bellows or the like so that it can move in the direction of arrow A while maintaining airtightness within the vacuum switch tube. The conductor 1c is connected to the connection terminal 7A via the flexible conductor 7, and the fixed conductor IA is connected to the connection terminal 3. The conductor IC is connected to the shaft 14 via an insulating rod 9A penetrating inside the insulating member 9.
It is driven by a drive lever 12 which rotates. The drive lever 12 and the insulating rod 9A are connected by a spring IO, and the drive lever 12 is connected by a spring I.
6 applies clockwise rotational force.

A movable core 15 is fixed to the drive lever 12 near its shaft 14, and the movable core 15 is attracted to an electromagnet 17.

The latch lever 20 is rotatably supported by a shaft 20A and biased counterclockwise by a spring 20B. Then, when the movable core 15 is attracted,
As shown in the figure, even if the movable core 15 is in a horizontal position and the roller 20C at the tip comes into contact with the movable core 15 and the attraction force of the electromagnet 17 disappears, the movable core 15 is held in the attraction position.

Another electromagnet 26 is located in front of the electromagnet 17 in the figure, and when energized, it rotates the movable core 26A in the direction of arrow C and pushes the roller 20C of the latch lever 20 with its tip 26B. Pushed latch lever 2
0 rotates clockwise and moves away from the movable core 15 to open the movable core. As a result, the drive lever 12 fixed to the movable core 15 is rotated clockwise by the spring 16 to lower the insulating rod 9A downward, and the movable contact IB is separated from the fixed contact IA.

This state is shown in FIG. 2(b). The stopper 4 is a member for restricting rotation of the drive lever 12.

[Problem to be solved by the invention] In conventional vacuum switches, an electromagnet is used to drive the drive lever, so even if attempts are made to make the switch smaller and lighter, it is limited by the size of the electromagnet, ff1ffi. receive. Furthermore, in order to install a heavy electromagnet, it is necessary to strengthen the switch case, and measures are also required to prevent the surge voltage generated from the electromagnet from affecting other electrical equipment, making it difficult to reduce costs. there were.

[Means for Solving the Problems] The switch of the present invention has a drive lever that is rotatably supported on a shaft and that applies an opening/closing driving force to the contacts of the switch through its rotation, in a direction in which no opening/closing driving force is applied to the contacts. A rotational force is applied by the biasing means to hold the drive lever in a predetermined position, and a rotational force in the direction of applying an opening/closing driving force to the drive lever is applied by the piezoelectric element, thereby causing the rotated drive lever to open and close at the contact point. The apparatus includes a holding means for holding a state in which a driving force is applied, and a driving means for releasing the holding state of the holding means.

[Operation] The drive lever rotates due to the elongation due to the longitudinal displacement effect of the piezoelectric element, and is held at the rotated position by the holding means.

The drive lever is returned to its original position by moving the holding means by the drive means.

[Example] Fig. 1(a) shows the state of the vacuum switch of the present invention when it is opened. In the figure, a fixed contact IA and a movable contact IB provided at the tip of a conductor IC are built into a vacuum switch tube 1 which is evacuated. The conductor 1c is attached to the switch tube 1 by, for example, a bellows so that it can move in the direction of arrow A while maintaining airtightness within the vacuum switch tube. The conductor IC is connected to the connection terminal 7 via the flexible conductor 7.
A, and the fixed conductor IA is connected to the ground terminal 3.

The conductor 1c is an insulating rod 9A that penetrates inside the insulating member 9.
One end is connected to a drive lever 12 which is rotatably supported by a shaft 14 via a shaft 14 . The drive lever 12 and the insulating rod 9A are connected via a buffer spring 16, and the spring 16 applies a counterclockwise rotational force to the drive lever 12.

Below the other end of the drive lever 12 is a commercially available laminated piezoelectric element 2 for applying clockwise rotational force to the drive lever 12.
9 is placed. The stacked piezoelectric element 29 is made by stacking a large number of piezoelectric elements with the same polarity, and the lead wire of the electrode of each piezoelectric element is led out. When a DC voltage of a predetermined voltage and polarity is applied to these lead wires, the length in the stacked direction is instantaneously expanded due to a known longitudinal displacement effect. The length of elongation is, for example, about 0.5 mm for an element with a stack height of 10W, but the elongation speed and force are large, so it is possible to generate a strong impact driving force with a relatively small and lightweight piezoelectric element. can. In the open state shown in FIG. 1(a), the contact member 28 at the end of the drive lever I2 is in contact with the piezoelectric element 29 due to the urging force of the strip 97 and 16. As shown in FIG. The contact member 28 is made of a hard material such as hardened steel. On the other hand, when the drive lever 12 reaches the position where the drive lever 12 pushes up the contact IB, a latch lever 30 for holding that state is attached to the shaft 3 at one end.
It is rotatably supported by 0A, and the spring 3
5 to rotate counterclockwise. Further, a roller 30B is provided at the other end of the latch lever 30.

When the drive lever 12 is in the position shown, the latch lever 30 is held down by the contact member 28 of the drive lever 12 and is in a horizontal position.

Next, the operation will be explained.

When a voltage of a predetermined polarity is applied to the piezoelectric element 29 in the open state shown in FIG. 1(a), the piezoelectric element 29 rapidly expands and applies an impact force so as to repel the contact member 28. As a result, the drive lever 12 rapidly rotates clockwise against the biasing force of the spring 12, pushing up the conductor IC via the spring 10 and the insulating rod 9A, and moving the contact IB to the contact IA.
Closely contact. At the same time, the latch lever 30 is
5 rotates counterclockwise as shown by arrow B, and the first
As shown in Figure (b), the drive lever 12 is brought into a vertical position and stops when it comes into contact with the piezoelectric element 36, and the drive lever 12 is held by the roller 30B. As a result, contacts IA and IB remain open continuously.

Next, when opening contacts IA and IB, piezoelectric element 36
Apply DC voltage to. As a result, as in the case of the piezoelectric element 29, the piezoelectric element 36 rapidly expands and applies a clockwise rotational force to the latch lever 30 as shown by the arrow.

As a result, the drive lever 12 is opened, rotated counterclockwise by the biasing force of the spring 16, and stops at the position where the contact member 28 comes into contact with the piezoelectric element 29. As the drive lever 12 rotates, the insulating rod 9A moves downward, and the contacts IA and
IB opens.

Note that the same effect can be obtained by using a DC voltage power source that charges a capacitor with DC voltage and discharges it as the DC voltage power source applied to the piezoelectric element. In this case, a power supply with a small current capacity can be used.

As another example, as shown in FIG. 1(c), the contact member 28 of the drive lever 12 is replaced with a piezoelectric element 38 and a voltage is applied to it in the direction of extension. The stretching force of the piezoelectric elements 29 and 38 provides substantially twice the rotational force as in the first embodiment, making the closing operation of the switch more reliable and stable.

[Effects of the Invention] According to the present invention, the driving force for opening and closing the contacts is obtained by the piezoelectric element having a large extension force despite being relatively small and lightweight, so that the vacuum switch can be made smaller and lighter.

Furthermore, since l1ll is reduced, the strength of the casing can also be reduced and manufacturing costs can be reduced. Another advantage is that the piezoelectric element does not generate surge voltage when driven, so it does not adversely affect other electrical equipment.

[Brief explanation of drawings]

FIG. 1(a) is a side view of the vacuum switch of this invention when it is opened, FIG. 1(b) is a side view of the vacuum switch of this invention when it is closed, and FIG. 1(c) is a side view of the vacuum switch of this invention when it is closed. FIG. 2(a) is a side view of another embodiment of the vacuum switch when closed, FIG. 2(a) is a side view of the conventional vacuum switch when closed, and FIG. 2(b) is a side view of the conventional vacuum switch when closed. It is a side view at the time of opening. It is. In the figure, 12 is a drive lever, 16 is a spring, 29, 3
6.38 is a piezoelectric element, and 30 is a latch lever.

Claims (3)

[Claims] (1) A drive lever that is rotatably supported and applies an opening/closing driving force to the contacts of the switch through its rotation, and an urging means that applies a rotational force to the drive lever in a direction that does not apply the opening/closing driving force to the contacts; A piezoelectric element that holds a drive lever given a rotational force by a biasing means in a predetermined position and also applies a rotational force in a direction to apply an opening/closing driving force to the drive lever, and a drive rotated by the rotational force given by the piezoelectric element. A switch having a holding means for holding a lever in a state where an opening/closing driving force is applied to a contact point, and a driving means for releasing the holding state of the holding means. (2) The switch according to claim 1, wherein the driving means is constituted by a piezoelectric element. (3) The switch according to claim 1, wherein another piezoelectric element is provided on a surface of the drive lever facing the piezoelectric element.