JPH05312118A - Extreme magneto-striction type actuator - Google Patents

Abstract

PURPOSE:To offset thermal expansion of an extreme magneto-striction rod and to eliminate generation of characteristic failure. CONSTITUTION:A coil bobin 8 with a solenoid coil 9 wound around it is provided in a casing 1, a stopper cylinder 16 with an extreme magnetic distortion rod 14 stored in it is inserted into a slide hole 8A of the coil bobin 8 and the stopper cylinder 16 is formed of a nonmagnetic material in correspondence with the extreme magneto-striction rod 14. Thereafter, the upper end of the extreme magnetic distortion rod 14 is made contact with a stopper part 16C of the stopper cylinder 16, the lower end side of the extreme magneto-striction rod 14 is installed on a valve body 4 through a spring bearing 6 and the valve body 4 is driven by the extreme magneto-striction 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, etc., and more particularly to a giant magnetostrictive actuator capable of preventing the characteristics from changing due to thermal expansion. Type actuator.

[0002]

2. Description of the Related Art Generally, a cylindrical casing and an object to be driven provided on one end side of the casing are extended in an axial direction in the casing, and one end side is attached to the object to be driven. A giant magnetostrictive rod, and provided in the casing located around the giant magnetostrictive rod,
A fuel injection valve using a giant magnetostrictive actuator consisting of an electromagnetic coil for expanding and contracting the giant magnetostrictive rod in the axial direction by applying a magnetic field to the giant magnetostrictive rod is known, for example, from JP-A-3-243174. ing.

In this type of conventional 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 can be reliably lifted against the valve spring. ..

[0005]

By the way, in the above-mentioned prior art, a valve body to be driven is provided at one end side of the casing, and a lid body is provided at the other end side of the casing, and the lid body and the valve body are provided. Since the supermagnetostrictive rod is positioned in the casing between and, the electromagnetic coil provided around the supermagnetostrictive rod generates heat due to external power supply, and the supermagnetostrictive rod is affected by the thermal effect at this time. Thermal expansion may occur 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. There is a problem that the characteristics of the injection flow rate and the like change due to thermal influence. Also, 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 preventing the above.

[0008]

The features of the structure adopted by the present invention for solving the above-mentioned problems are that a coefficient of thermal expansion corresponding to the supermagnetostrictive rod is provided between the electromagnetic coil and the supermagnetostrictive rod. With a non-magnetic material, provided is a stopper tube formed in a tubular shape with a length dimension for accommodating the giant magnetostrictive rod in the axial direction, and the stopper tube has one end side, which is the opening end side, fixed to the casing, The other end side is configured to be engaged with the other end side of the giant magnetostrictive rod.

Further, it is preferable that an urging means is provided on one end side of the casing, and the supermagnetostrictive rod is always urged toward the other end side of the stopper cylinder by the urging means. ..

[0010]

With the above construction, when the giant magnetostrictive rod thermally expands so as to extend in the axial direction due to heat generation of the electromagnetic coil, the stopper cylinder also thermally expands in the axial direction correspondingly. The expansion amount can be absorbed so as to be offset on the other end side of the stopper cylinder.

[0011]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3 by taking a giant magnetostrictive injection valve as an example.

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 cylindrical valve body provided on the inner peripheral side of the lower portion of the casing 1, and the valve body 2 has a cylindrical shape with an outer diameter corresponding to the inner diameter of the casing 1, as shown in FIG. The formed tubular portion 2A, the bottom portion 2B extending radially inward from the lower end side of the tubular portion 2A and formed in the shape of a relatively thick disc, and extending upward from the center of the bottom portion 2B. A small-diameter guide cylinder 2D provided with a plurality of guide protrusions 2C, 2C, ... that are spaced apart in the circumferential direction on the inner peripheral side and extend in the axial direction, and a bottom portion that is located below the guide cylinder 2D. A valve seat 2E formed by expanding in a tapered shape on the inner peripheral side of 2B.
The valve seat 2E forms a fuel injection port between the valve seat 2E and a valve portion 4D of the valve body 4 which will be described later.

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 which is an object to be driven, and the valve body 4 has an annular step portion 4C between an upper shaft portion 4A and a lower shaft portion 4B, and a lower shaft portion. A hemispherical valve portion 4D is integrally formed on the lower end side of 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 and seated on the valve seat 2E. Further, a valve spring 5 is arranged around the guide cylinder 2D between the annular step portion 4C of the valve body 4 and the bottom portion 2B of the valve body 2. The valve is normally biased in the closing direction. When the valve body 4 is opened against the valve spring 5 by the later-described giant magnetostrictive rod 14, 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 provided movably in the valve body 2, and the spring retainer 6 has a cylindrical protrusion 6A on the lower surface side.
Is provided so as to project downward, and the upper shaft portion 4A of the valve body 4 is slidably inserted into the cylindrical protrusion 6A. Then, a minute gap S is interposed between the upper surface 6B of the cylindrical projection 6A and the upper end of the upper shaft portion 4A, and the valve portion 4D is inadvertently separated from the valve seat 2E when the valve body 4 is thermally expanded. It prevents you from doing it. 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 located around the cylindrical projection 6A of the spring receiver 6 and arranged between the spring receiver 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 an urging means, and the super-magnetostrictive rod 14 is constantly urged upward through the spring receiver 6 or the like, so that the super-magnetostrictive rod 1
An initial load is applied to No. 4.

Reference numeral 8 indicates a stepped cylindrical coil bobbin arranged in the casing 1, 9 indicates 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 power supply. 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 is formed on the inner peripheral side of the coil bobbin 8 and extends in the axial direction.
A stopper tube 16 is fitted inside.

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. , Each terminal pin 10 on the lid 12
A small-diameter cylindrical seal member 13, 13 is attached around the
Rainwater from the outside is prevented from entering the coil bobbin 8 from around the terminal pins 10. The lid 12 is caulked and fixed by the 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. Further, through holes 12A, 11A 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.
Are 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 formed of a giant magnetostrictive material such as neodymium (Nd) -iron master alloy or dysprosium (Dy) -iron, terbium (Tb) -iron master alloy as a rod having an elongated cylindrical shape, and is an electromagnetic coil. By the magnetic field from 9, for example, a magnetic field of 1 kOe (kilo-Oersted) causes axial elongation and deformation at a ratio of 1000 PPM (1000 × 10 ⁻⁶ ) with respect to the total length L. Also, the giant magnetostrictive rod 1
4 has a coefficient of thermal expansion α (linear expansion coefficient) of, for example, about 1 × 10 ⁻⁵ / ° C., and an axial dimension (L × α) with respect to the total length L each time the ambient temperature rises by 1 ° C. Only thermally expands.

Here, the giant magnetostrictive rod 14 has its upper end side end surface 14A abutted on a stopper portion 16C of a stopper cylinder 16 which will be described later and is axially positioned, and the lower end side thereof is the stopper cylinder 1.
6 protrudes 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 having 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 is formed of a metal material having a coefficient of thermal expansion α corresponding to the giant magnetostrictive rod 14 into an elongated tubular shape, and has a tubular portion. A disc-shaped stopper portion 16C having an abutting surface 16B having a flat lower surface is integrally formed on the upper end side of 16A. 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 flange portion 16D is formed.
The outer peripheral side of is clamped between the annular projection 1C of the casing 1 and the upper end of the tubular portion 2A of the valve body 2, 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 thicknesses of the stopper portion 16C and the flange portion 16D, and the giant magnetostrictive rod 14 housed inside is as shown by a phantom 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. Further, the stopper tube 16
The stopper portion 16C has a contact surface 16B of the giant magnetostrictive rod 14
Is in surface contact with the upper end side end surface 14A with a relatively large contact area.

The giant magnetostrictive injection valve according to this embodiment has the above-mentioned structure, 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 by the electromagnetic coil 9 as described above, the giant magnetostrictive rod 14 is stretched and deformed in accordance with the strength of the magnetic field at this time, and the spring bearing 6 receives the buffer plate 15. The valve body 4 while being displaced downward through
Is lifted downward with a lift amount as shown by a characteristic line 18 shown in FIG. 4 to separate the valve portion 4D from the valve seat 2E, so that the fuel in the valve body 2 is transferred to the valve seat 2E and the valve portion 4D.
It is jetted to the outside from between. In this case, the upper end side end surface 14A of the giant magnetostrictive rod 14 contacts the stopper portion 16C of the stopper cylinder 16 and the upward displacement is restricted, so that the giant magnetostrictive rod 14 is stretched and deformed downward, and the valve body 4 is deformed.
Is opened against the set spring 7 and the valve spring 5.

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 the valve body 4 can be prevented from being opened accidentally until the electromagnetic coil 9 is supplied with the injection pulse.
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 downwardly by this, and in the worst case, the valve portion 4D of the valve body 4 separates from the valve seat 2E and causes a seal failure. Becomes In addition, the injection pulse is supplied to the electromagnetic coil 9 to expand and deform the giant magnetostrictive rod 14, and the valve body 4
When the valve is opened and closed, the amount of thermal expansion of the giant magnetostrictive rod 14 is added, and the lift amount of the valve body 4 becomes excessively larger than the normal lift amount as indicated by a characteristic line 19 shown by a virtual line in FIG.

Therefore, in the present embodiment, the stopper cylinder 16 is formed in a cylindrical shape from a nonmagnetic material having a coefficient of thermal expansion corresponding to the coefficient of thermal expansion α of the giant magnetostrictive rod 14, and the length of the cylindrical portion 16A. Is made to correspond to the total length L of the giant magnetostrictive rod 14, and the upper end side end face 14A of the giant magnetostrictive rod 14 is pressed against the stopper portion 16C to position the giant magnetostrictive rod 14. As a result, when the giant magnetostrictive rod 14 thermally expands as shown by the phantom line in FIG. 3, the tubular portion 16A of the stopper tube 16 also thermally expands, so that the giant magnetostrictive rod on the stopper portion 16C side of the stopper tube 16 does. The thermal expansion of 14 can be absorbed and offset, the upward expansion due to the thermal expansion of the giant magnetostrictive rod 14 is allowed, and the downward expansion can be prevented.

Therefore, according to the present embodiment, it is possible to effectively prevent the lift amount of the valve body 4 from changing due to the thermal expansion of the giant magnetostrictive rod 14, and to prevent the valve body 4 from changing as shown by the characteristic line 18 in FIG. It can be opened and closed with a regular lift amount.
Further, the spring load of the setting spring 7 can be prevented from changing due to thermal expansion of the giant magnetostrictive rod 14, and a constant initial load can be continuously applied 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.

In the above embodiment, the valve body 4 and the spring bearing 6 are
However, the valve body 4 and the spring receiver 6 may be integrated, and in this case, the valve spring 5 is omitted and the setting spring 7 is formed. The valve body 4 may be constantly urged in the valve closing direction by.

Further, in the above-mentioned embodiment, the valve body 4 of the outward opening type is used.
However, the present invention is not limited to this, and is applied to, for example, a super magnetostrictive injection valve using an inward opening type valve body as described in the prior art. Maybe,
In this case, it is sufficient to use a giant magnetostrictive rod that undergoes contraction deformation in the axial direction when a magnetic field is applied.

Further, the giant magnetostrictive actuator of the present invention is not limited to the one applied to the giant magnetostrictive injection valve, but the giant magnetostrictive actuator may be used instead of an electromagnetic solenoid such as an electromagnetic on-off valve. In that case, one end side of the giant magnetostrictive rod may be attached to a spool valve body, a poppet valve body, or the like, which is an object 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.

[0034]

As described above in detail, according to the present invention, the stopper cylinder is formed of a non-magnetic material having a coefficient of thermal expansion corresponding to the giant magnetostrictive rod, and the giant magnetostrictive rod is housed in the stopper cylinder. Since the magnetic field is applied by the electromagnetic coil, one end side of the stopper tube is fixed to the casing, and the other end side is engaged with the other end side of the giant magnetostrictive rod, the giant magnetostrictive rod is heated by the heat of the electromagnetic coil. Even when inflated,
The thermal expansion of the giant magnetostrictive rod can be offset by the thermal expansion of the stopper cylinder, and the occurrence of characteristic defects can be effectively prevented. Further, when applied to a giant magnetostrictive injection valve or the like, it is possible to prevent the lift amount of the valve body from changing due to thermal expansion, and it is possible to eliminate the occurrence of defective sealing.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a giant magnetostrictive injection valve according to an 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.

[Explanation of symbols]

 1 Casing 2 Valve Body 2E Valve Seat 3 Fuel Flow Hole 4 Valve Body (Target Object) 5 Valve Spring 6 Spring Bearing 7 Setting Spring (Biasing Means) 9 Electromagnetic Coil 14 Super Magnetostrictive Rod 16 Stopper Cylinder 16C Stopper 16D Flange Department

Claims (2)

[Claims] 1. A cylindrical casing and an ultra-longitudinal member that is provided in the casing so as to extend in the axial direction so as to drive an object to be driven provided on one end side of the casing, and one end side of which is attached to the object to be driven. A giant magnetostrictive system comprising a magnetostrictive rod and an electromagnetic coil which is provided in the casing around the giant magnetostrictive rod and which expands and contracts the giant magnetostrictive rod in the axial direction by applying a magnetic field to the giant magnetostrictive rod. In the actuator, between the electromagnetic coil and the giant magnetostrictive rod, a non-magnetic material having a coefficient of thermal expansion corresponding to the giant magnetostrictive rod has a length dimension for accommodating the giant magnetostrictive rod in the axial direction. A stopper cylinder formed in a cylindrical shape is provided, one end side of the stopper cylinder, which is an opening end side, is fixed to the casing, and the other end side is engaged with the other end side of the giant magnetostrictive rod. A giant magnetostrictive actuator characterized by the above. 2. The urging means is provided on one end side of the casing, and the urging means constantly urges the giant magnetostrictive rod toward the other end side of the stopper cylinder. Giant magnetostrictive actuator.