JPH0622571A - Giant magnetostrictive actuator - Google Patents

Abstract

(57) [Abstract] [Purpose] The thermal expansion of the giant magnetostrictive rod is offset, the occurrence of characteristic defects is eliminated, and the displacement of the driven object is doubled. [Structure] A coil bobbin 8 around which an electromagnetic coil 9 is wound is provided in a casing 1, a stopper cylinder 16 accommodating a giant magnetostrictive rod 14 is inserted into a sliding hole 8A of the coil bobbin 8, and the stopper cylinder 16 is superposed. It is made of a giant magnetostrictive material having a coefficient of thermal expansion corresponding to that of the magnetostrictive rod 14 and having a magnetostrictive characteristic opposite to that of the giant magnetostrictive rod 14. Then, the stopper tube 16
When the upper end of the giant magnetostrictive rod 14 is brought into contact with the stopper portion 16C of the above, the lower end side of the giant magnetostrictive rod 14 is attached to the valve body 4 via the spring bearing 6, and when the valve body 4 is driven by the giant magnetostrictive rod 14, The amount of lift of the valve body 4 can be doubled by adding the contraction of the stopper cylinder 16 to the extension of the magnetostrictive rod 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a giant magnetostrictive actuator suitable for use in, for example, a giant magnetostrictive injection valve, an on-off valve, and the like, and more particularly to a giant magnetostrictive actuator capable of preventing its characteristics from changing due to thermal expansion. Type actuator.

[0002]

2. Description of the Related Art Generally, a cylindrical casing and a magnetic field are applied to drive an object to be driven which is provided inside the casing by extending in the axial direction of the casing. A supermagnet consisting of a giant magnetostrictive rod which sometimes expands and contracts in the axial direction, and an electromagnetic coil which is provided in the casing around the giant magnetostrictive rod and which applies a magnetic field to the giant magnetostrictive rod by being energized from the outside. A fuel injection valve using a magnetostrictive actuator is disclosed in, for example, Japanese Patent Laid-Open No.
No. 243174, etc.

In this type of prior art fuel injection valve,
A valve seat having a fuel injection port is provided on one end side of the casing, and the valve body is always urged in a valve closing direction by a valve spring so that an inward opening type valve body serving as a driving object is seated on the valve seat. At the same time, one end side of the giant magnetostrictive rod is fixed to the valve body, and when the giant magnetostrictive rod is contracted by the magnetic field from the electromagnetic coil, the giant magnetostrictive rod lifts the valve body against the valve spring, The fuel in the casing is injected from the injection port to the outside.

At the other end of the casing, there is provided a lid that abuts against the other end of the giant magnetostrictive rod, and the lid pushes the giant magnetostrictive rod together with the valve toward the valve seat side. The spring load of the valve spring is adjusted.
When the giant magnetostrictive rod is contracted and deformed by the magnetic field from the electromagnetic coil, the giant magnetostrictive rod is restricted from being separated from the lid body, and the valve body is reliably lifted against the valve spring.

[0005]

By the way, in the above-mentioned prior art, a valve body to be driven is provided on one end side of the casing, and a lid body is provided on the other end side of the casing. Since the giant magnetostrictive rod is positioned in the casing in the axial direction between the and, when the electromagnetic coil provided around the giant magnetostrictive rod generates heat due to external energization, the giant magnetostrictive rod will be affected by the heat at that time. The rod may thermally expand in the axial direction between the lid body and the valve body. Since the giant magnetostrictive rod has a larger coefficient of thermal expansion than the casing, and the lid is integrally fixed to the casing, the giant magnetostrictive rod expands toward the valve body side during thermal expansion.

Therefore, in the prior art, not only the spring load of the valve spring changes due to thermal expansion of the giant magnetostrictive rod, but also the lift amount of the valve body changes when the giant magnetostrictive rod is deformed by the magnetic field from the electromagnetic coil. However, there is a problem in that the characteristics of the injection flow rate and the like change due to thermal effects. If the valve body to be driven is an open type and the valve body is opened when the giant magnetostrictive rod expands and deforms, the valve body is displaced in the valve opening direction due to thermal expansion of the giant magnetostrictive rod. There is a problem in that it may be separated from the valve seat, causing a defective seal or the like.

The present invention has been made in view of the above-mentioned problems of the prior art. Even when the giant magnetostrictive rod thermally expands, it can be offset by the thermal expansion of the stopper cylinder, resulting in defective characteristics. It is an object of the present invention to provide a giant magnetostrictive actuator capable of effectively displacing an object to be driven, such as a valve body, while effectively preventing the above.

[0008]

The features of the configuration adopted by the present invention to solve the above-mentioned problems are that the giant magnetostrictive rod is housed in the axial direction between the electromagnetic coil and the giant magnetostrictive rod. A stopper tube formed in a cylindrical shape having a length dimension and axially positioning the supermagnetostrictive rod in the casing is provided, and the stopper tube has a coefficient of thermal expansion corresponding to that of the supermagnetostrictive rod. It is formed of a giant magnetostrictive material having a magnetostrictive characteristic opposite to that of the rod.

[0009]

With the above construction, when the giant magnetostrictive rod thermally expands so as to extend in the axial direction due to the heat generation of the electromagnetic coil or the like, the stopper cylinder also thermally expands in the axial direction correspondingly. The amount of thermal expansion can be absorbed by the thermal expansion of the stopper cylinder. Further, since the stopper cylinder is formed of a giant magnetostrictive material having a magnetostrictive characteristic opposite to that of the giant magnetostrictive rod, when the magnetic field from the electromagnetic coil causes, for example, the giant magnetostrictive rod to expand and deform in the axial direction, the stopper cylinder is Since the stopper cylinder is contracted and deformed in the axial direction, the driving amount (displacement amount) of the driven object can be doubled by the contraction of the stopper cylinder and the expansion of the giant magnetostrictive rod.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 5 by taking a giant magnetostrictive injection valve using a giant magnetostrictive actuator as an example.

1 to 4 show a first embodiment of the present invention.

In the drawing, reference numeral 1 denotes a cylindrical casing formed of a magnetic material such as electromagnetic stainless steel in a stepped cylindrical shape, and the casing 1 has caulked portions 1 at both upper and lower ends thereof.
A and 1B are provided, and an annular protrusion 1C is provided on the inner peripheral side of the caulked portion 1B at a predetermined dimension above.

Reference numeral 2 denotes a bottomed tubular valve body provided on the inner peripheral side of the lower portion of the casing 1. The valve body 2 is cylindrical with an outer diameter corresponding to the inner diameter of the casing 1, as shown in FIG. The formed cylindrical portion 2A, a bottom portion 2B provided at the lower end side of the cylindrical portion 2A and formed in a relatively thick disk shape, and extending upward from the center of the bottom portion 2B, the inner peripheral side A small diameter guide tube 2D formed with a plurality of guide projections 2C, 2C, ...
The valve seat 2E is located below the guide cylinder 2D and is formed by expanding in a tapered shape on the inner peripheral side of the bottom portion 2B. The valve seat 2E and a valve portion 4D of a valve body 4 which will be described later. To form a fuel injection port.

Here, the valve body 2 is a casing 1.
The ring-shaped projection 1C is fitted in the inside from the lower end side, and the upper end of the cylindrical portion 2A is inserted through a flange portion 16D of a stopper cylinder 16 described later.
The bottom surface of the bottom portion 2B on the outer peripheral side is fixed to the caulking portion 1B in a state of being brought into contact with the casing 1 to be integrated in the casing 1. Further, in the cylindrical portion 2A of the valve body 2, fuel circulation holes 3 and 3 are bored in the radial direction so as to penetrate the casing 1, and each of the circulation holes 3 is provided with a fuel pump (both of which are provided through a fuel pipe or the like). Fuel (not shown) is circulated in the valve body 2.

Reference numeral 4 denotes an outer opening type valve body as a driven object provided on the lower end side of the casing 1, and the valve body 4 is detachable between the upper shaft portion 4A and the lower shaft portion 4B. An annular step portion 4C is provided, and a hemispherical valve portion 4D is integrally formed on the lower end side of the lower shaft portion 4B. The lower shaft portion 4B of the valve body 4 is inserted into the guide cylinder 2D of the valve body 2, and the spherical upper surface side of the valve portion 4D is separated from the valve seat 2E.
Sit down. Further, a valve spring 5 is disposed between the annular step portion 4C of the valve body 4 and the bottom portion 2B of the valve body 2 so as to be located around the guide cylinder 2D. The valve is normally biased in the closing direction. Then, when the valve body 4 is opened by the giant magnetostrictive rod 14 described later against the valve spring 5, the fuel in the valve body 2 is valved to the valve seat 2E via the guide projections 2C of the guide cylinder 2D. It is jetted to the outside from between the portion 4D.

Reference numeral 6 denotes a spring retainer movably provided in the valve body 2. The spring retainer 6 is provided with a cylindrical projection 6A protruding downward from the center of the lower surface side, and is provided in the cylindrical projection 6A. The upper shaft portion 4A of the valve body 4 is slidably inserted. Then, the upper surface 6B of the tubular projection 6A and the upper shaft portion 4A
A small gap S is provided between the valve body 4D and the upper end of the valve body 4D to prevent the valve portion 4D from being unintentionally separated from the valve seat 2E during thermal expansion of the valve body 4. A shallow recess 6C is formed in the center of the upper surface of the spring receiver 6, and the lower end of the giant magnetostrictive rod 14 is fitted into the recess 6C via a buffer plate 15 described later.

Reference numeral 7 denotes a setting spring which is located around the cylindrical projection 6A of the spring bearing 6 and is arranged between the spring bearing 6 and the bottom portion 2B of the valve body 2. The setting spring 7 is a valve spring. 5, the super-magnetostrictive rod 1 is constituted by urging means and constantly urges the super-magnetostrictive rod 14 upward via the spring receiver 6 or the like.
An initial load is applied to No. 4.

Reference numeral 8 denotes a stepped cylindrical coil bobbin disposed in the casing 1, 9 denotes an electromagnetic coil wound around the coil bobbin 8, and the electromagnetic coil 9 is erected on the upper end side of the coil bobbin 8. It is connected to the terminal pins 10 and is excited by external energization to generate a magnetic field. The electromagnetic coil 9 applies a magnetic field to the giant magnetostrictive rod 14 so that the giant magnetostrictive rod 14 is stretched and deformed in the axial direction to drive the valve body 4 in the valve opening direction. A sliding hole 8A extending in the axial direction is formed on the inner peripheral side of the coil bobbin 8, and a stopper cylinder 16 is inserted into the sliding hole 8A.

Reference numeral 11 denotes an annular spacer arranged in the casing 1 so as to abut the upper end of the coil bobbin 8, and reference numeral 12 denotes an annular lid body located on the spacer 11 and fixed to the upper end side of the casing 1. The lid 12 is made of a magnetic material and forms a magnetic circuit around the electromagnetic coil 9 together with the casing 1. Further, small-diameter cylindrical seal members 13, 13 are attached to the lid body 12 around the respective terminal pins 10, and the respective seal members 13 have the respective terminal pins 10 and the lid body 12.
It is designed to electrically insulate between and. And
The lid 12 is caulked and fixed by a caulking portion 1A in the casing 1, and the coil bobbin 8 and the spacer 11 and the like are positioned in the casing 1 with the annular protrusion 1C. In addition, through holes 12A corresponding to the sliding holes 8A of the coil bobbin 8 are provided on the inner peripheral sides of the lid 12 and the spacer 11.
11A is formed.

Reference numeral 14 denotes a giant magnetostrictive rod inserted through the stopper tube 16 into the sliding hole 8A of the coil bobbin 8,
The giant magnetostrictive rod 14 is an elongated cylindrical rod having a positive magnetostrictive property from a giant magnetostrictive material such as neodymium (Nd) -iron master alloy or dysprosium (Dy) -iron, terbium (Tb) -iron master alloy. The magnetic field from the electromagnetic coil 9 is formed, and a magnetic field of, for example, 1 kOe (kilo-Oersted) is applied to the entire length L at 1000 PPM (1000
It is stretched and deformed in the axial direction with a stretch amount ΔL at a ratio of × 10 ^-6 ). The giant magnetostrictive rod 14 is, for example, 1 × 10.
^It has a coefficient of thermal expansion α (coefficient of linear expansion) of about ⁻⁵ / ° C., and expands axially by a dimension (L × α) with respect to the total length L every time the ambient temperature rises by 1 ° C.

Here, the supermagnetostrictive rod 14 is axially positioned with the upper end face 14A abutting a stopper portion 16C of a stopper cylinder 16 described later, and the lower end side of the stopper cylinder 1
6 projects slightly downward from the open end side of the spring 6, and is fitted into the recess 6C of the spring receiver 6 via the buffer plate 15. The giant magnetostrictive rod 14 is constantly urged upward by the setting spring 7 via the spring receiver 6, and the upper end side thereof is pressed against the stopper portion 16C of the stopper cylinder 16. Further, the buffer plate 15 is formed of an elastic resin material into a disk shape with a predetermined plate thickness, and when the giant magnetostrictive rod 14 is stretched and deformed to open the valve body 4, the shock received from the valve body 4 is alleviated. .

Further, 16 is a sliding hole 8 of the coil bobbin 8.
A stopper cylinder inserted in A together with the giant magnetostrictive rod 14 is shown. The stopper barrel 16 has a coefficient of thermal expansion α corresponding to that of the giant magnetostrictive rod 14, and is made of the same giant magnetostrictive material as that of the giant magnetostrictive rod 14. The contact surface 1 is formed in an elongated cylindrical shape with a negative magnetostrictive characteristic and has a flat lower surface on the upper end side of the cylindrical portion 16A.
A disc-shaped stopper portion 16C which is 6B is integrally formed. Further, a large-diameter flange portion 16D that projects radially outward is integrally formed on the lower end side of the cylindrical portion 16A that is the opening end side of the stopper cylinder 16, and the outer peripheral side of the flange portion 16D is of the casing 1. Annular projection 1C and valve body 2
It is sandwiched between the upper end of the tubular portion 2A and the upper end of the tubular portion 2A, and is fixed to the casing 1.

The cylindrical portion 16A of the stopper cylinder 16
Has a length dimension corresponding to the total length L of the giant magnetostrictive rod 14 including the thickness of the stopper portion 16C and the flange portion 16D, and the giant magnetostrictive rod 14 housed inside has a length as shown by a virtual line in FIG. When it thermally expands in the axial direction, it thermally expands with a length in the axial direction corresponding to it, and the thermal expansion component of the giant magnetostrictive rod 14 is absorbed on the stopper portion 16C side. 6 is prevented from being displaced in the axial direction.

The stopper portion 16 of the stopper tube 16
In C, the contact surface 16B is the upper end side end surface 14 of the giant magnetostrictive rod 14.
Surface contact with A is made with a relatively large contact area, and the initial load from the setting spring 7 is effectively applied to the giant magnetostrictive rod 14. Since the stopper cylinder 16 has a negative magnetostriction characteristic contrary to the giant magnetostrictive rod 14, the magnetic field from the electromagnetic coil 9 causes, for example, 1 kOe (kilo-oersted).
Magnetic field of 1000PPM (1000 ×
It is shrunk and deformed with a shrinkage amount ΔL in the axial direction at a ratio of 10 ⁻⁶ ).

The giant magnetostrictive injection valve according to this embodiment has the above-mentioned construction, and its operation will be described below.

First, the characteristic line 17 shown in FIG.
When a magnetic field is applied to the giant magnetostrictive rod 14 and the stopper cylinder 16 by the electromagnetic coil 9 as described above,
Since the giant magnetostrictive rod 14 expands and deforms according to the strength of the magnetic field at this time, and the stopper cylinder 16 conversely contracts and deforms, the giant magnetostrictive rod 14 has a stopper cylinder whose lower end side corresponds to the amount of expansion ΔL at this time. From the flange portion 16D of the sixteen, the spring bearing 6 is projected downward with a double projection amount (2 × ΔL), for example, and the spring receiver 6 is largely displaced downward via the buffer plate 15.

The giant magnetostrictive rod 14 is used for the valve body 4 as shown in FIG.
As shown by the characteristic line 18 in FIG. 1, the downward lift is performed with a large lift amount substantially corresponding to the protrusion amount (2 × ΔL),
By separating the valve portion 4D from the valve seat 2E, the fuel in the valve body 2 is injected outward from between the valve seat 2E and the valve portion 4D. In this case, the upper end face 14A of the giant magnetostrictive rod 14 contacts the stopper portion 16C of the stopper tube 16 and the upward displacement is restricted, so that the giant magnetostrictive rod 14 is stretched and deformed downward and the stopper tube 1 is also deformed.
The contraction deformation of 6 also causes the valve body 4 to be displaced downward, opening the valve body 4 against the set spring 7 and the valve spring 5 with a large lift amount.

Further, since the valve body 4 is an outwardly opening type valve body, when the super magnetostrictive injection valve is used as an in-cylinder direct injection type injection valve, the pressure in the combustion chamber (not shown) is increased. Is the valve body 4
Even when an external force is applied to the valve body 4, the valve body 4 is pressed against the valve seat 2E and continues to be seated, and it is possible to prevent the valve body 4 from opening accidentally until the injection pulse is supplied to the electromagnetic coil 9.
However, the giant magnetostrictive rod 14 thermally expands due to the heat from the combustion chamber and the heat generation of the electromagnetic coil 9, and the upper end side end face 14A is axially displaced as shown by a phantom line in FIG.

By the way, the upper end face 14A of the giant magnetostrictive rod 14 is replaced with the stopper portion 16C of the stopper cylinder 16,
When fixed to the casing 1 via the lid or the like as described in the prior art, the coefficient of thermal expansion α of the giant magnetostrictive rod 14 is larger than the coefficient of thermal expansion of the casing 1.
In No. 4, the upward expansion due to thermal expansion is restricted and the downward expansion occurs. Then, when the giant magnetostrictive rod 14 thermally expands downward, the valve body 4 is pushed downward by this, and in the worst case, the valve portion 4D of the valve body 4 separates from the valve seat 2E, causing a seal failure. Becomes Further, when the injection pulse is fed to the electromagnetic coil 9 to expand and deform the giant magnetostrictive rod 14, the amount of thermal expansion of the giant magnetostrictive rod 14 is added to the amount of expansion,
The valve body 4 continues to lift in a valve open state as indicated by a characteristic line 19 shown by a virtual line in FIG.

Therefore, in this embodiment, the stopper cylinder 16 is made of a giant magnetostrictive material having a coefficient of thermal expansion corresponding to the coefficient of thermal expansion α of the giant magnetostrictive rod 14 and having a magnetostrictive characteristic opposite to that of the giant magnetostrictive rod 14. While being formed in a tubular shape, the length dimension of the tubular portion 16A is made substantially equal to the total length L of the giant magnetostrictive rod 14, and the upper end side end surface 14A of the giant magnetostrictive rod 14 housed in the stopper barrel 16 is pressed against the stopper portion 16C. , The giant magnetostrictive rod 1
4 positioning is performed.

As a result, when the giant magnetostrictive rod 14 thermally expands as shown by the phantom line in FIG. 3, the stopper cylinder 16
Similarly, the tubular portion 16A of the stopper also thermally expands, so that the stopper tube 1
On the side of the stopper portion 16C of 6, the thermal expansion component of the giant magnetostrictive rod 14 can be absorbed and offset, and the upward extension due to the thermal expansion of the giant magnetostrictive rod 14 can be allowed and the downward extension can be prevented.
When the electromagnetic coil 9 is energized to open and close the valve body 4, the extension deformation of the giant magnetostrictive rod 14 and the contraction deformation of the stopper cylinder 16 are added to open the valve body 4 with a double lift amount. It can be closed.

Therefore, according to this embodiment, the valve body 4 is opened,
When the electromagnetic coil 9 is energized to close the valve, the expansion deformation of the giant magnetostrictive rod 14 and the contracting deformation of the stopper cylinder can be added to double the lift amount of the valve body 4, and a super magnetostrictive material made of expensive supermagnetostrictive material can be doubled. Total length L of magnetostrictive rod 14 and stopper tube 16
Can be shortened, and the giant magnetostrictive injection valve can be formed short and compact.

Further, it is possible to effectively prevent the occurrence of a sealing failure or the like when the valve body 4 is closed due to the thermal expansion of the giant magnetostrictive rod 14, and the spring load of the setting spring 7 causes the thermal expansion of the giant magnetostrictive rod 14. It is possible to prevent the change due to the change, and it is possible to continuously apply a constant initial load to the giant magnetostrictive rod 14.

On the other hand, the valve body 4 is heated by heat from the combustion chamber.
Is thermally expanded, the minute gap S shown in FIG. 2 formed between the upper shaft portion 4A of the valve body 4 and the spring receiver 6 causes
The amount of thermal expansion of the valve element 4 can be absorbed, and even in this case, the valve portion 4D can be prevented from being unintentionally separated from the valve seat 2E.
Then, when the injection pulse is supplied to the electromagnetic coil 9 to open the valve body 4 and the giant magnetostrictive rod 14 is expanded and deformed by the magnetic field at this time, the spring bearing 6 is displaced downward against the setting spring 7. Then, it collides with the upper shaft portion 4A of the valve body 4 so as to eliminate the minute gap S, but the shock at this time can be prevented from being directly transmitted to the giant magnetostrictive rod 14 by the buffer plate 15, and the durability of the giant magnetostrictive rod 14 can be improved. You can improve the property.

Next, FIG. 5 shows a second embodiment of the present invention, and the feature of this embodiment is that the giant magnetostrictive actuator is applied to an inward opening type injection valve. In this embodiment, the same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the figure, reference numeral 21 indicates a cylindrical casing formed of a magnetic material such as electromagnetic stainless steel in a stepped cylindrical shape, and the casing 21 is substantially the same as the casing 1 described in the first embodiment. Is formed, and the caulking portion 21 is formed on the upper end side.
Although the casing A is provided, the casing 21 has a tubular fitting portion 21C below the annular step portion 21B.

Reference numeral 22 denotes a covered cylindrical valve body fitted and fixed to the inner peripheral side of the fitting portion 21C of the casing 21, and the lower end side of the valve body 22 is closed by a valve seat member 23, and the valve seat member An injection hole 2 having a valve seat 23A at 23
3B is formed. Further, the valve body 22 has a through hole 22B formed at the center of the lid portion 22A.
A valve shaft 26A, which will be described later, is slidably inserted into 2B via a cylindrical seal member 24. A fuel flow hole 25 is formed in the valve body 22 in the radial direction. The flow hole 25 allows fuel from a fuel pump (neither shown) to flow into the valve body 22 through a fuel pipe or the like. It is supposed to be distributed.

Reference numeral 26 denotes an inward opening type valve body provided as a driven object on the lower end side of the casing 21.
6 is a seal member 2 in the through hole 22B of the valve body 22.
Valve seat 26A slidably inserted through the valve seat 26 and the valve seat 2 of the valve seat member 23 integrally formed on the lower end side of the valve shaft 26A.
3A and a poppet-type valve portion 26B that is seated on and off. Further, the valve shaft 26A and the valve portion 26B of the valve body 26
A spring receiver 27 formed of an annular flat plate is provided between the spring receiver 27 and the lid portion 22A of the valve body 22 as a biasing means for constantly biasing the valve body 26 in the valve closing direction. A valve spring 28 is provided. Communication holes 27A, 27A, ... Are bored at predetermined intervals in the spring receiver 27, and the communication holes 27A allow the valve body 22 to communicate with the valve seat member 23 at all times.

Reference numeral 29 designates a stepped cylindrical coil bobbin disposed in the casing 21, and the coil bobbin 29 is formed in substantially the same manner as the coil bobbin 8 described in the first embodiment, and the coil bobbin 29 has an electromagnetic field. The coil 9 and the terminal pins 10, 10 connected to the electromagnetic coil 9 are provided. A sliding hole 29A extending in the axial direction is formed on the inner peripheral side of the coil bobbin 29.
A stopper cylinder 30, which will be described later, is inserted in A.

Reference numeral 30 designates a stopper cylinder inserted together with the giant magnetostrictive rod 14 into the sliding hole 29A of the coil bobbin 29. The stopper cylinder 30 is substantially the same as the stopper cylinder 16 described in the first embodiment. It has a coefficient of thermal expansion α corresponding to the giant magnetostrictive rod 14 and is formed of a giant magnetostrictive material similar to that of the giant magnetostrictive rod 14 into a slender tubular shape with negative magnetostrictive characteristics. Abutment surface 3 with flat side
A disk-shaped stopper portion 30C having 0B is integrally formed. Further, a large-diameter flange portion 30D that projects radially outward is integrally formed on the lower end side of the tubular portion 30A that is the opening end side of the stopper cylinder 30, and the outer peripheral side of the flange portion 30D is the casing 21. It is sandwiched between the annular step portion 21B and the coil bobbin 29 and fixed to the casing 21.

Reference numeral 31 denotes a displacement transmission mechanism for transmitting the displacement of the giant magnetostrictive rod 14 to the valve body 26. The displacement transmission mechanism 31 is slidably inserted into the fitting portion 21C of the casing 21, A disk-shaped sliding plate 32 integrally provided with boss portions 32A and 32B on both upper and lower surfaces, a bracket 33 radially outwardly protruding from the boss portion 32B of the sliding plate 32, and A transmission link 34 that is pin-coupled to the bracket 33 and hangs downward, and is formed by bending in a substantially V shape, and is rotatably pin-coupled to a fitting portion 21C of the casing 21 through a pin 35. The rotary link 36 has one end side pin-coupled to the transmission link 34, and the other end side pin-coupled to the valve shaft 26A of the valve body 26.

Here, the boss portion 32A of the sliding plate 32 is inserted into the tubular portion 30A of the stopper tube 30 from below, and when the stopper tube 30 is fixed in the casing 21, the lower end of the giant magnetostrictive rod 14 is fixed. It is pressed against the side end face with a predetermined load. Then, when the electromagnetic coil 9 is energized to expand and deform the giant magnetostrictive rod 14 and contract and deform the stopper tube 30, the lower end side of the giant magnetostrictive rod 14 is largely displaced downward in the stopper tube 30, and the casing 2
Since the sliding plate 32 is pushed downward together with the transmission link 34 in the fitting portion 21C of No. 1, the rotation link 36 is thereby moved.
Is rotated in the direction of arrow A to open the valve element 26 against the valve spring 28 with a large lift amount.

Thus, in this embodiment having the above-described structure, it is possible to obtain substantially the same effects as the first embodiment, but especially in this embodiment, the giant magnetostrictive rod 14 and the valve body 26 are provided. By providing the displacement transmission mechanism 31 between the two, the expansion deformation of the giant magnetostrictive rod 14 and the contraction deformation of the stopper cylinder 30 can be added to open and close the inward opening type valve body 26 with a large lift amount. Thus, the giant magnetostrictive rod 14 and the stopper tube 30 made of an expensive giant magnetostrictive material can be formed in a short length.

In the first embodiment, the valve body 4 and the spring bearing 6 are described as being formed separately, but instead of this, the valve body 4 and the spring bearing 6 are integrated. Alternatively, in this case, the valve spring 5 may be omitted, and the valve spring 4 may be constantly biased in the valve closing direction by the setting spring 7.

In each of the above embodiments, the giant magnetostrictive rod 1 is used.
4 is made of a giant magnetostrictive material having a positive magnetostrictive characteristic,
Although the stopper cylinder 16 (30) is described as being formed of a giant magnetostrictive material having a negative magnetostrictive characteristic, the present invention is not limited to this, and for example, a giant magnetostrictive rod is made of a giant magnetostrictive material having a negative magnetostrictive characteristic. The stopper cylinder is formed of a giant magnetostrictive material having a positive magnetostrictive characteristic, and when a magnetic field is applied to these, the valve body or the like as a drive target is opened and closed with a large lift amount. Good.

Further, in each of the above-described embodiments, the case where the giant magnetostrictive actuator is applied to the giant magnetostrictive injection valve has been described as an example, but the present invention is not limited to this, and for example, an electromagnetic on-off valve or the like electromagnetic valve. The giant magnetostrictive actuator may be used instead of the solenoid. In this case, one end of the giant magnetostrictive rod may be attached to the spool valve body, poppet valve body, or the like to be driven. Further, it may be applied to a disc brake or the like, and in this case, the expansion / contraction deformation of the giant magnetostrictive rod may be transmitted to the friction pad to apply the braking force to the disc.

[0047]

As described in detail above, according to the present invention, the stopper cylinder is formed of a giant magnetostrictive material having a coefficient of thermal expansion corresponding to that of the giant magnetostrictive rod and having a magnetostrictive characteristic opposite to that of the giant magnetostrictive rod. Since the super-magnetostrictive rod is housed in the stopper cylinder to perform axial positioning, even when the super-magnetostrictive rod thermally expands due to heat generation of the electromagnetic coil or the like, the super-magnetostrictive rod expands due to the thermal expansion of the stopper cylinder. It is possible to offset the amount of thermal expansion and to effectively prevent the occurrence of characteristic defects and the like. Further, when a magnetic field is applied to the giant magnetostrictive rod and the stopper cylinder by the electromagnetic coil, for example, when the giant magnetostrictive rod expands and deforms in the axial direction, the stopper cylinder contracts and deforms in the axial direction.
By the contraction of the stopper cylinder and the expansion of the giant magnetostrictive rod, the drive amount (displacement amount) of the drive target can be doubled,
Various effects can be obtained, such as shortening the length of the giant magnetostrictive rod made of an expensive giant magnetostrictive material and the stopper cylinder to form a compact body as a whole.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an outer opening type giant magnetostrictive injection valve according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part in FIG. 1 showing a valve body side.

FIG. 3 is an enlarged view of a main part in FIG. 1 showing an upper end side of a giant magnetostrictive rod.

FIG. 4 is a characteristic diagram showing an injection pulse and a valve lift amount.

FIG. 5 is a vertical sectional view showing an inward opening type giant magnetostrictive injection valve according to a second embodiment.

[Explanation of symbols]

 1, 21 Casing 2, 22 Valve body 2E, 23A Valve seat 3,25 Fuel flow hole 4,26 Valve body (object to be driven) 5,28 Valve spring (biasing means) 6,27 Spring receiving 7 Setting spring ( Energizing means) 9 Electromagnetic coil 14 Giant magnetostriction rod 16,30 Stopper tube 16C, 30C Stopper part 16D, 30D Flange part 31 Displacement transmission mechanism 35 Pin 36 Rotation link

Claims (1)

[Claims] 1. A tubular casing, and a magnetic field applied to drive an object to be driven which is provided in the casing by extending in the axial direction of the casing and provided on one end side of the casing. A giant magnetostrictive rod that expands and contracts in the axial direction,
A giant magnetostrictive actuator comprising an electromagnetic coil which is provided in the casing around the giant magnetostrictive rod and applies a magnetic field to the giant magnetostrictive rod by being energized from the outside, wherein the electromagnetic coil and the giant magnetostrictive rod are provided. And a stopper tube which is formed in a tubular shape with a length dimension for accommodating the giant magnetostrictive rod in the axial direction, and which positions the giant magnetostrictive rod in the axial direction in the casing. Is a giant magnetostrictive material having a coefficient of thermal expansion corresponding to that of the giant magnetostrictive rod and having a magnetostrictive characteristic opposite to that of the giant magnetostrictive rod.