JPH0358129B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic relay, and more particularly to a piezoelectric relay using a piezoelectric element that generates distortion when voltage is applied.

[Conventional technology]

The mainstream of conventional piezoelectric relays has been to operate a relay by moving a movable contact using a bimorph, which is made by laminating a plurality of piezoelectric element plates that produce transverse strain, as a driving body. A piezoelectric element plate using bimorph requires a predetermined length and width in order to ensure the pressing force and movement distance of the contacts necessary to form an electric circuit, and it also requires a certain length and width in the direction of movement of the piezoelectric element plate, which is approximately perpendicular to this width direction. A contact drive mechanism consisting of a movable piece and a spring mechanism for contact drive is arranged side by side. Therefore, the piezoelectric relay has a columnar outer shape due to the width of the piezoelectric element plate and the length of the contact drive mechanism, and the piezoelectric relay inevitably becomes larger (for example, Japanese Utility Model Application Publication No. 185154/1983).

On the other hand, a piezoelectric relay using a laminated piezoelectric drive body in which a plurality of piezoelectric elements are stacked in the direction of the electric field by utilizing longitudinal effect strain with high energy conversion efficiency was proposed by the same applicant in Japanese Patent Application No. 58-49863 (Japanese Patent Application Laid-Open No. Showa 59-175531
(No. 2). The piezoelectric relay proposed by this proposal secures contact pressing force due to the characteristics of the laminated piezoelectric drive body, but requires a displacement amplification mechanism.Compared to the piezoelectric relay using the above-mentioned bimorph, it can be made smaller, but the external shape is vertical. It becomes columnar with width and length.

[Problem that the invention seeks to solve]

The conventional piezoelectric relay described above has a large piezoelectric element or a large displacement amplifying mechanism as a means for amplifying the displacement of the piezoelectric element, and has a columnar outer shape, so it is suitable for mounting on a thin plate of a printed wiring board, which has been frequently used in recent years. There was a problem that it was inappropriate.

An object of the present invention is to solve the above problems and provide a piezoelectric relay that is thin and suitable for mounting on a printed wiring board.

[Means for solving problems]

The piezoelectric relay of the present invention uses a laminated piezoelectric actuator in which a plurality of piezoelectric elements are laminated as a contact drive source, and has a piezoelectric actuator with a thickness approximately equal to or less than the thickness of the piezoelectric actuator in the length direction.
It has a structure in which the center axes of the hinge spring included in the displacement magnification mechanism, the arm body coupled to the hinge spring, and the movable contact spring mechanism included in the contact assembly mechanism are arranged on substantially the same plane and juxtaposed.

To be more specific, the box has an opening shape or a U-shape with a thickness approximately equal to the thickness of the piezoelectric drive body, and fixes and holds the drive input terminal and contact assembly of the piezoelectric drive body. It has an outer frame into which a lead-out terminal for drawing out an electric circuit is inserted, and a mounting part which fixes and holds a contact drive part. The contact drive unit includes a drive board that is fixed to the mounting part of the box, a piezoelectric drive body that has one end fixed to the drive board and a driver at the other end, and one end fixed to the drive board with a hinge spring. A displacement magnifying mechanism is provided, in which a drive element is pressed at the middle part of the arm connected to the spring, and a drive protrusion at the other end moves by magnifying the displacement of the piezoelectric drive body based on the principle of leverage. This displacement magnification mechanism has at least one set of a hinge spring and an arm, and in the case of multiple sets, an additional set is provided between the arm pressed by the driver and the drive protrusion. The contact assembly includes a movable contact spring mechanism that presses against the drive protrusion and has a movable contact, and a movable contact spring that moves the movable contact by displacement of the drive protrusion to open and close an electric circuit with the fixed contact; A fixed contact holder having a fixed contact holder.

The movable parts of the drive board, piezoelectric drive body, hinge spring, arm body, and movable contact spring, which are the components of the contact drive unit and the contact assembly unit, are attached to the case and the inner wall of the outer box attached to the case. and their respective center females are arranged substantially on the same plane.

〔Example〕

Next, the piezoelectric relay of the present invention will be described by way of embodiments with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is an exploded perspective view of FIG. 1. The box 10 includes a square-shaped outer frame 11 having a thickness of 4 mm, and a flat plate that is fixed to two opposing sides and one other side of the outer frame 11 and partially closes one opening of the square shape. A mounting part 1 formed of and for mounting and fixing the contact drive part 20
It has 2. The contact drive unit 20 integrally laminates a plurality of piezoelectric elements such that internal electrodes are alternately located between them, and generates mechanical strain in which the piezoelectric elements expand and contract in the stacking direction, that is, the length direction, due to an electric field. Piezoelectric drive body 2 with dimensions of ×3 × 9 mm ³
1, a drive element 22, a drive board 23, a fixed body 24, a displacement magnification mechanism 25, and a booster circuit 26 incorporating a circuit for creating an input voltage for the piezoelectric drive body 21. A drive element 22 is fixed to one end of the piezoelectric drive body 21 in the length direction and has a cross section of 2×3 mm ² . The drive board 23 has a thickness of 3 mm and the contact drive part 22 is attached to the mounting plate 1.
Attach and fix to 2. The fixed body 24 is the piezoelectric drive body 2
1 is fixed to the drive board 23. Displacement magnification mechanism 25
has a thickness of 2 mm and includes hinge springs 251 and 252, and an arm body 2 that connects these hinge springs 251 and 252.
53 and a driving protrusion 254 are provided in juxtaposition.
The hinge spring 251 is a plate spring with a width of 2 mm, and one end is fixed to the drive board 23 and the other end is fixed to the arm body 253.
Forms 3 fulcrums. The hinge spring 252 has both ends fixed to each arm body 253 and has the role of transmitting displacement. One of the arm bodies 253, or in the case of a plurality of arm bodies, one of the ends contacts the drive element 22 at the intermediate part, and the other end is provided with a drive protrusion 254 for driving the contact point. The hinge springs 251 and 252 are arranged with their central axes on substantially the same plane and their plate spring surfaces substantially parallel to each other.
1,252 together with the arm body 253 that has a thickness of 2 mm.
A displacement magnification mechanism 25 is formed. Contact assembly part 30
has a movable contact spring 31 and a fixed contact holder 32. The movable contact spring 31 is a plate spring having a width of 2 mm, and has one end fixed to one of the lead-out terminals 14 and a movable contact at the other end. The movable contact spring 31 is a drive protrusion that presses against the drive protrusion 254 and is linked to the displacement of the piezoelectric drive body. 254
The movable contact is moved by the displacement of . The fixed contact holder 32 has a fixed contact facing the movable contact and is fixed to the lead-out terminal 14 . The pull-out terminal 14 is inserted and fixed to one side of the outer frame 11 together with the input terminal 13, the movable contact spring 31 is arranged substantially parallel to the hinge springs 251, 252, and the central axis is also arranged and fixed on substantially the same plane. Therefore, the displacement magnifying mechanism 25
The contact assembly part 30 has a thickness of approximately 2 mm and the outer frame 1
It is fixed inside 1. The input terminal 13 and the pull-out terminal 14 are provided to protrude in the same direction, and an outer box (not shown) is tightly covered with the case 10 from the side opposite to the terminal insertion side in the terminal protrusion direction, and is attached to the outer frame 11. Glued.

In the above embodiment, the thickness is specified as 2 mm, 3 mm, and 4 mm, but these dimensions are based on the minimum thickness of the movable part that is disposed within the box so as not to contact the fixed part, and then This indicates the thickness of the drive board and also the thickness of the outer surface of the box, and is determined by the dimensions of the piezoelectric drive body. Although it has been described that the outer frame is square-shaped, it may be U-shaped, and the shape is not limited. Moreover, although the attachment part was explained as a flat plate, it is also possible to fix it directly to the outer frame. The input terminals and extraction terminals are shown protruding in a plane parallel to the displacement plane, that is, in the direction of the plate surface of the thin plate relay, but in order to be mounted directly on a printed wiring board, at least the tip should protrude perpendicularly to the plate surface direction. be able to. Although it has been explained that a booster circuit is provided, it can be provided outside and removed from the inside. In the above embodiment, the outer box has a deep shape except for one side where the terminal is located, but it can be made into a shallow shape by covering the entire surface with the above-mentioned mounting portion and allowing the terminal to protrude in the thickness direction. It should be noted that the one shown in the drawing is the best in terms of manufacturing and assembly workability.

〔Effect of the invention〕

As explained above, the piezoelectric relay of the present invention uses a small-sized laminated piezoelectric drive body in wear units, and the components of the contact drive part and the contact assembly part are arranged side by side so that the dimensions are approximately the same as the thickness of the piezoelectric drive body. This makes it possible to achieve the effect of realizing a thin rectangular shape and making it convenient to mount on a printed wiring board.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the piezoelectric relay of the present invention, and FIG. 2 is an exploded perspective view of FIG. 1. 10...Box, 11...Outer frame, 12...Mounting portion, 13...Input terminal, 14...Output terminal, 20
...Contact drive unit, 21...Piezoelectric drive body, 22...
Driver element, 23... Drive board, 24... Fixed body, 2
5... Displacement magnification mechanism, 26... Boost circuit, 30...
...Contact assembly part, 31...Movable contact spring, 32...
Fixed contact holder, 251, 252... hinge spring, 253... arm body, 254... drive protrusion.

Claims (1)

[Scope of Claims] 1 A plurality of piezoelectric elements are integrally laminated so that internal electrodes are alternately located between them, and an applied voltage causes the piezoelectric elements to expand and contract in the lamination direction, causing mechanical strain at one end. A piezoelectric drive body having a drive element and the other end serving as a fixing part, a drive board fixing the fixing part of the piezoelectric drive body, and one end fixed to the former drive board with a hinge spring and coupled to the hinge spring. A displacement amplifying mechanism having a drive protrusion at the other end that presses the drive element in the middle part of the arm body and moves by magnifying the displacement of the drive element using the principle of leverage, and the piezoelectric drive body, drive board, hinge spring , and a contact drive part in which the central axes of each of the arm bodies are juxtaposed on substantially the same plane, each of which has substantially the same thickness or width as the piezoelectric drive body in a direction perpendicular to this plane; displacement of the drive protrusion; a movable contact spring mechanism having a movable contact spring that moves a movable contact to open and close an electric circuit with a fixed contact; and a fixed contact holder having a fixed contact; a contact assembly disposed substantially in the same plane as the central axis of the components of the contact drive unit and having substantially the same thickness or width as the piezoelectric drive body in a direction perpendicular to the plane and juxtaposed to the contact drive unit; an outer frame having a thickness substantially equal to the thickness of the piezoelectric drive body, which fixes and holds the drive input terminal and contact assembly of the piezoelectric drive body, and into which a draw-out terminal for drawing out an electric circuit is inserted, and a contact; A case having a mounting part that fixes and holds the drive part; and an outer box of the case in which the input terminal and the extraction terminal protrude to the outside and which encloses the contact drive part and the contact assembly part. Piezoelectric relay.