JPS62134983A - Bistable displacement amplifier - Google Patents

Abstract

PURPOSE:To improve accuracy and response of a bistable displacement amplifier as an actuator of a fuel injection valve or the like having constant amplification ratio of a flexible member and excellent responsiveness by using laminated piezoelectric ceramics. CONSTITUTION:When an electric field is not applied to a laminated piezoelectric ceramics 16, a flexible member 17 is deflected forward to hold a switching valve 7 in a closed position, while when the electric field is applied to a pulse, both operating points 15c of a lever 15 are abruptly extended outward, the member 17 is pulled at both ends 17b, inverted at the center as designated by a broken line in the drawing to move the valve 17 to an opened position. At this time, a rear permanent magnet 11 acts on a flange 9, and the valve 17 is held at the opened position in a stable state. When the electric field is again applied in a pulse shape, both the points 15c are abruptly extended outward, the member 17 is inverted at the center to move the valve 7 to the closed position.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a laminated type E [electroceramic displacement amplification device] which is used in an actuator such as a fuel injection valve.

(Prior Art) Conventionally, the central part of a flexible member made of a band-shaped elastic body or the like is bent in advance and the displacement of the laminated +=electroceramics is transmitted to both ends of the flexible member, thereby bending both ends of the one-way member. Vertical displacement! There is a displacement amplification device that utilizes the resulting large lateral displacement of the flexible member (
For example, S△1. -Report.

No. 800502, page 10, see Fig. 16).

(Problems to be Solved by the Invention) However, when this displacement amplification device is used to drive a fuel injection valve, etc., the amplification ratio changes due to variations in the lateral displacement of the flexible member. - It is not possible to increase the temperature. In addition, in order to return the lateral displacement of the flexible member, a load such as a return spring must always be applied in the opposite direction to the direction of displacement, which lengthens the displacement time by that amount, resulting in the response of the fuel injection valve, etc. Sexuality becomes worse.

An object of the present invention is to provide a multilayer piezoelectric ceramic displacement amplification device in which the amplification ratio of a flexible member is constant and responsiveness is good.

(Means for Solving the Problems) This invention is a first step to solving the above problems.
a W4-layer piezoelectric ceramic fixed on the S substrate; a lever member whose force point is joined to the corner of the laminated piezoelectric ceramic, has at least two points of action, and whose fulcrum is fixed on the substrate; , a flexible member made of a band-shaped elastic body whose central part is pre-flexed and whose both ends are connected to the point of action of the lever member; and a connecting member that connects one end of the reciprocating moving body to the central part of the flexible member. , 1lf arranged near the front and rear of the magnetic flange provided on the interlocking body.
This is a bistable displacement amplification device characterized by comprising a magnet that maintains flff body motion in a stable state at both end positions δ.

(Example) -C1 This invention will be described based on the drawings showing the example above. 1 and 2 are examples in which the bistable displacement amplification device according to the present invention is applied to a fuel injection valve. The fuel injection valve has a cylindrical casing 1 configured as a combination of a front part 1a, a middle part 1b, and a rear part 1C. Casing 1
The inside of the front part 1a and the center part 1b has a communication 1" in the center. A front compartment 2a and a central compartment 2b are separated by a partition wall 2.
A fuel passage portion 3 is fitted inside the rear portion 1C. 4 is a valve housing that connects the front section 2a1. : Fitted and fixed, fuel injection] 6 is provided at the tip. Reference numeral 7 denotes an on-off valve, which is inserted into a guide hole 4a provided in the valve housing 4 so as to be able to reciprocate. A valve element 7a is provided at the tip of the on-off valve 7, and a flange 8 is provided on the outer periphery of the central portion, which comes into contact with the stopper 5 at the end of the stroke of the on-off valve 7. A flange 9 made of a magnetic material is provided on the outer periphery of the on-off valve 7 located roughly behind the stopper 5.

An annular front permanent magnet 10 and a rear permanent magnet 11 are arranged between the stopper 5 and the partition wall 2 on the tangential inner surface of the front section 2a.
are fitted with the base T12 in between. The flange 9 receives the magnetism of the front permanent magnet 1o when the r# on-off valve is in the closed position relative to the fuel injection I Ll 6, and receives the magnetic force of the rear permanent magnet 11 when it is also in the open position. It is located in

Reference numeral 13 denotes a main body of bistable displacement amplification R1ff1, which is inserted and fixed into the center portion 1b of the casing 1 via a substrate 14.

A lever member 15 having a planar shape shown in FIG. 1 and a vertical cross-sectional shape shown in FIG. 2 is mounted on the substrate 14.
-・Provided by body molding. Reference numeral 15a designates a power point portion of the lever member 15, 15b a fulcrum portion, and 15C a power point portion.

A space is provided between the substrate 14 and the force point portion 15a, and a laminated piezoelectric layer 16 is fitted therein. Reference numeral 17 denotes a flexible member made of a spring steel strip plate, and both ends 17b are connected to the inner action point 15c of the lever 15, with the center portion 17a being bent. The center portion 17a of the roughly flexible member is held in a groove 188 of a coupling member 18 fixed to an end of the on-off valve 7. .

As shown in FIG. 2, when approaching the coupling member 18 made of a magnetic material, l! An Il knob sensor 19 is attached. This has a well-known structure that changes the distance from the coupling member 18 to the strength of the eddy current. Git?
The glue lead 1120 from the tube sensor 19 and the lead wires 21 and 22 from the laminated pressure ff1t laminated material 16 are connected to the terminal 23. It passes through, fills the space of the central section 11j 2 b, passes through the inside of the on-off valve 7, and reaches around the valve element 7a.

In the bistable displacement amplification unit configured as described above, when no electric field is acting on the laminated piezoelectric ceramic 16, the flexible member 17 is bent forward, and the on-off valve 7 is moved by 1 m.
Holding in place. Next, as shown in FIG. 4, when an electric field is applied in a pulsed manner, both points of action 15 C
l, rapidly expands outward, and the bending part @17 is at both ends 17b.
is pulled, and the center part is reversed as shown by the chain line in the figure to become 17
1. Move the closed valve 7 to the open position. At this time, the rear permanent magnet 11 acts on the flange 9, and the on-off valve 7 remains stable in the open position. When the electric field is applied again in a pulsed manner, both points of action 15c rapidly spread outward in the same manner as described above, and the center portion of the flexible member 17 is reversed as shown by the solid line in the drawing, thereby moving the on-off valve 7 to the closed position. At this time, the front permanent magnet 10 acts on the flange 9, and the on-off valve 7 remains stable in the open position.

Since the bistable displacement amplification device of this invention does not have a return spring or the like, the lifting member 17 does not always return the on-off valve 7 to the closed position when the engine is stopped. Therefore, when the Gisep-Hinley 19 detects the distance from the coupling member 18 and is in the open position, a pulse current is further applied to return the on-off valve 7 to the closed position.

FIG. 3 shows an embodiment with two flexure members 26,27. Both ends of the flexible members 26, 27 are fixed to both points of action 15C of the lever 15.

The coupling member 28 engages the flexible member 26,27 and closes the opening/closing valve 7.
In the open state, the state shown in the figure is maintained by the magnetic force of the front permanent magnet 10. Lamination pressure '11ft? When an electric field acts on the Lamix 16, the flexible member 26 urges the opening/closing valve in the opening direction, and the magnetic force of the rear permanent magnet 11 stabilizes the valve in the open position. When the electric field acts again, the on-off valve 7 is pushed forward by the bias of the flexible member 27, and the surface part permanent 1I is pushed forward.
The magnetic force of the t1 stone 10 brings it into a stable open state.

In the above embodiment, the C bistable state is created by the faf 1 unit norange 9 of the on-off valve 7 and the permanent magnets 10° 11 placed in the vicinity of the front and back, but instead of these, permanent magnets and electromagnets are used. This is possible by using .

(Effects of the Invention) Since the present invention is a bistable displacement amplification device using the laminated electroceramics described above, the amplification ratio of the flexible member is constant, and the response is excellent. The accuracy and responsiveness of actuators such as fuel injection valves can be improved.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a horizontal sectional view of a fuel injection valve in which the bistable displacement amplification device according to the invention is used as an actuator, and Fig. 2 is a partial longitudinal sectional view of Fig. 1. 3 is a horizontal sectional view of a main part of another embodiment, and FIG. 4 is an explanatory diagram showing the relationship between the opening/closing state of the fuel injection valve and the electric field strength applied to the laminated piezoelectric ceramics. 7... Opening/closing valve 9... Magnetic flange 10.11... Permanent magnet 14... Substrate 15... Lever member 15a... Force point part 15b... Fulcrum part 15c... Point of action Part 16...Laminated J" (electronic ceramics 17.26.27...Flexible member 18.28...Joining member

Claims (1)

[Claims] a laminated piezoelectric ceramic fixed on a substrate, a lever member whose force point is joined to the top of the laminated piezoelectric ceramic, has at least two points of action, and whose fulcrum is fixed on the substrate, and a band-shaped elastic body. a flexible member whose central portion is pre-flexed and whose both ends are coupled to the point of action of the lever member; a coupling member which couples one end of the reciprocating movable body to the central portion of the flexible member; 1. A bistable displacement amplification device comprising: magnets disposed near the front and rear of a magnetic flange to hold the moving body in a stable state at both end positions of operation.