JPH069164U - Giant magnetostrictive actuator - Google Patents

Abstract

(57) [Abstract] [Purpose] Prevents the giant magnetostrictive rod from expanding thermally and eliminates the occurrence of characteristic defects. A gas sealing part 10 is provided between the coil cylinder 6 and the coil bobbin 6 outside the stopper cylinder 9 for accommodating the giant magnetostrictive rod 11, and the gas sealing part 10 has heat insulating air, nitrogen,
A gas G such as carbon dioxide is enclosed to block heat from the electromagnetic coil 7 and prevent heat from being transferred to the giant magnetostrictive rod 11. Even if the electromagnetic coil 7 generates heat, this heat can be prevented from being transmitted to the giant magnetostrictive rod 11, the giant magnetostrictive rod 11 is thermally expanded and its length is changed, and the valve body 4 provided at the tip of the spring bearing 3 is Can be prevented from being unintentionally separated from the valve seat, resulting in a defective seal or the like.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a giant magnetostrictive actuator suitably used in, for example, a giant magnetostrictive injection valve and an on-off valve, and more particularly to a giant magnetostrictive actuator capable of preventing characteristics from changing due to thermal expansion.

[0002]

[Prior art]

 Generally, a cylindrical casing and an axial direction when the magnetic field is 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, an electromagnetic coil that is provided inside the casing around the giant magnetostrictive rod, applies a magnetic field to the giant magnetostrictive rod by being energized from the outside, and the other end of the casing. A fuel injection valve using a giant magnetostrictive actuator, which is provided on the side of the casing and comprises a positioning member for axially positioning the giant magnetostrictive rod in the casing, is known from, for example, Japanese Patent Laid-Open No. 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 an inward opening type valve body to be driven should be seated on the valve seat. , The valve body is always urged in the valve closing direction by a valve spring, and 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 is The rod lifts the valve body against the valve spring, and the fuel in the casing is injected from the injection port to the outside.

Further, a lid body as a positioning member that abuts on the other end side end surface of the giant magnetostrictive rod is provided on the other end side of the casing, and the giant magnetostrictive rod is seated together with the valve body by the lid body. The spring load of the valve spring is adjusted by pressing the valve spring toward the side. 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]

[Problems to be solved by the device]

 By the way, in the above-mentioned conventional technique, 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, and the giant magnetostrictive rod is provided between the lid body and the valve body. Since the magnet is positioned in the casing in the axial direction, when the electromagnetic coil provided around the supermagnetostrictive rod generates heat due to external energization, the supermagnetostrictive rod and the lid body are affected by the thermal effect at this time. Thermal expansion may occur in the axial direction with 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 element when the giant magnetostrictive rod is deformed by the magnetic field from the electromagnetic coil. Changes, and there is a problem that the characteristics of the injection flow rate and the like change due to thermal effects. In addition, 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. Then, the valve seat may be separated from the valve seat, which may cause a seal failure.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention can effectively prevent the heat generated from the electromagnetic coil from being transferred to the giant magnetostrictive rod, so that the giant magnetostrictive rod can be axially moved. It is an object of the present invention to provide a giant magnetostrictive actuator capable of preventing thermal expansion of the actuator and stably driving a driven object such as a valve body.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, a first invention is to drive a cylindrical casing and an object to be driven which is provided inside the casing by extending in the axial direction of the casing and provided at one end side of the casing. Therefore, a giant magnetostrictive rod that expands and contracts in the axial direction when a magnetic field is applied, and a giant magnetostrictive rod that is provided inside the casing located around the giant magnetostrictive rod and is energized from the outside In a giant magnetostrictive actuator consisting of an electromagnetic coil for applying a magnetic field, a heat insulating means for blocking heat from the electromagnetic coil from reaching the giant magnetostrictive rod is provided between the giant magnetostrictive rod and the electromagnetic coil. The characteristic configuration is adopted.

A second invention is a cylindrical casing and a magnetic field for driving an object to be driven which is provided inside the casing by extending in the axial direction of the casing and which is provided on one end side of the casing. A giant magnetostrictive rod that expands and contracts in the axial direction when applied, a coil bobbin provided in the casing around the giant magnetostrictive rod, wound around the coil bobbin, and energized from the outside. Thus, in a giant magnetostrictive actuator consisting of an electromagnetic coil that applies a magnetic field to the giant magnetostrictive rod, the coil bobbin is made of a heat insulating material that blocks heat from the electromagnetic coil from reaching the giant magnetostrictive rod. Is adopted.

[0010]

[Action]

 With the above configuration, even if the electromagnetic coil generates heat due to energization, the heat at this time can be blocked from being transmitted to the giant magnetostrictive rod by the heat insulating means or the coil bobbin having the heat insulating property, and the giant magnetostrictive rod can be prevented from thermally expanding. .

[0011]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS.

1 and 2 show a first embodiment of the present invention.

In the drawings, reference numeral 1 denotes a cylindrical casing which is formed of a magnetic material such as electromagnetic stainless steel into a stepped cylindrical shape and constitutes an outer frame of a giant magnetostrictive injection valve. The casing 1 has both upper and lower ends. The sides are caulked portions 1A, 1B, and annular step portions 1C, 1D, 1E are formed on the inner peripheral side of the casing 1 so as to be spaced from each other by a predetermined distance in the axial direction between the caulked portions 1A, 1B. Further, a fuel inflow hole 1F is formed in the casing 1 in a radial direction between the annular step portions 1D and 1E, and a fuel pump is connected to the inflow hole 1F via a pipe (neither is shown). , The fuel is flowed into the casing 1.

Reference numeral 2 denotes a valve seat member provided on the inner periphery of the lower end side of the casing 1, and the valve seat member 2 is formed of a material having high wear resistance into a relatively thick disc shape, The member 2 is fixed by caulking between the caulking portion 1B of the casing 1 and the annular step portion 1E, and closes the lower end side of the casing 1. Further, a fuel injection port 2A is formed on the center side of the valve seat member 2, and a mortar-shaped valve seat 2B is formed outwardly around the injection port 2A.

Reference numeral 3 denotes a spring bearing provided on the lower end side in the casing 1, and the spring bearing 3 is a circle slidably fitted in the casing 1 between the annular step portions 1D and 1E of the casing 1. The spring receiving portion 3A is generally composed of a plate-shaped spring receiving portion 3A and a cylindrical boss portion 3B protruding downward from the center of the lower surface of the spring receiving portion 3A. 3 C is formed. The lower end of a giant magnetostrictive rod 11, which will be described later, is fitted and mounted in the recess 3C of the spring receiver 3.

Reference numeral 4 denotes a valve body as a drive target which is attached to the lower end side of the casing 1 from the outside of the casing 1. The valve body 4 includes a rod-shaped valve shaft 4A and a lower end of the valve shaft 4A. It is composed of a hemispherical valve portion 4B integrally formed with the valve shaft 4A so as to open. Then, the valve body 4 inserts the upper end of the valve shaft 4A into the casing 1 through the injection port 2A of the valve seat member 2, and fixes the upper end of the valve shaft 4A to the lower end of the boss portion 3B of the spring receiver 3. It is worn and installed. The valve body 4 is axially displaced together with the spring bearing 3 when the giant magnetostrictive rod 11 is expanded and contracted, and the valve portion 4B is seated on the valve seat 2B of the valve seat member 2 to open and close the valve.

Reference numeral 5 denotes a setting spring that is located around the boss portion 3B of the spring receiver 3 and that is arranged between the spring receiving portion 3A and the valve seat member 2 and serves as a biasing means. The giant magnetostrictive rod 11 is constantly urged upward through the spring bearing portion 3A of the bridge 3 to apply an initial load to the giant magnetostrictive rod 11.

Reference numeral 6 denotes a stepped cylindrical coil bobbin arranged in the casing 1, and an inner peripheral side of the coil bobbin 6 has a stopper insertion hole 6A extending in the axial direction.

Reference numeral 7 denotes an electromagnetic coil wound around the coil bobbin 6, and the electromagnetic coil 7 is connected to terminal pins 8 and 8 erected on the upper end side of the coil bobbin 6 and excited by external energization. And generate a magnetic field. By applying a magnetic field to the giant magnetostrictive rod 11, the electromagnetic coil 7 axially expands and transforms the giant magnetostrictive rod 11, and drives the valve body 4 fixed to the spring bearing 3 in the valve opening direction.

Reference numeral 9 denotes a stopper tube provided in the stopper insertion hole 6 A of the coil bobbin 6, and the stopper tube 9 is an elongated tubular shape made of a nonmagnetic material having a thermal expansion coefficient close to that of the giant magnetostrictive rod 11. A cylindrical portion 9A formed in the axial direction in the stopper insertion hole 6A of the coil bobbin 6, a stopper portion 9B closing the upper end side of the cylindrical portion 9A, and a lower end side of the cylindrical portion 9A. And a flange portion 9C having a flange shape. Further, an annular lid portion 9D having a diameter larger than that of the tubular portion 9A is formed on the stopper tube 9 between the tubular portion 9A and the flange portion 9C, and the annular lid portion 9D serves as the stopper tube 9. When inserted into the stopper insertion hole 6A of the coil bobbin 6, the lower end side of the stopper insertion hole 6A is fitted to close the stopper insertion hole 6A. A tubular space is formed between the stopper cylinder 9 and the coil bobbin 6 as a gas sealing portion 10. Inside the gas sealing portion 10, for example, air, nitrogen, and nitrogen are used as heat insulating means having a heat insulating action. A gas G such as carbon oxide is enclosed.

Further, in the stopper cylinder 9, the cylindrical portion 9A is formed with a length dimension substantially corresponding to the total length L of the giant magnetostrictive rod 11 including the thicknesses of the stopper portion 9B and the flange portion 9C, and the coefficient of thermal expansion thereof. Also substantially corresponds to the coefficient of thermal expansion of the giant magnetostrictive rod 11, so even if the heat from the electromagnetic coil 7 is transferred to the giant magnetostrictive rod 11 and the giant magnetostrictive rod 11 thermally expands in the axial direction, the stopper cylinder is 9 substantially expands correspondingly and absorbs the thermal expansion of the giant magnetostrictive rod 11 on the stopper portion 9B side, thereby preventing the giant magnetostrictive rod 11 from displacing the spring bearing 3 in the axial direction. It is like this.

Reference numeral 11 denotes a giant magnetostrictive rod inserted into the tubular portion 9 A of the stopper barrel 9. The giant magnetostrictive rod 11 is, for example, neodymium (Nd) -iron master alloy or dysprosium (D y) -iron. , A terbium (Tb) -iron master alloy, etc., is formed as a slender cylindrical rod having a positive magnetostrictive characteristic, and the supermagnetostrictive rod 11 is, for example, 1 kOe (kg) by the magnetic field from the electromagnetic coil 7. In the magnetic field of Oersted, it is elongated and deformed in the axial direction at a ratio of 1000 PPM (1000 × 10 ⁻⁶ ) with respect to the total length L. Further, the giant magnetostrictive rod 11 has a coefficient of thermal expansion α (coefficient of linear expansion) of, for example, about 1 × 10 ⁻⁵ / ° C., and is dimensioned in the axial direction with respect to the total length L when the ambient temperature rises by t ° C. ΔL,

[0023]

## EQU1 ## Thermal expansion of ΔL = L × α × t.

Here, the lower end side of the giant magnetostrictive rod 11 projects downward from the stopper cylinder 9 and is fitted into the concave portion 3C of the spring receiver 3, and the upper end side thereof contacts the stopper portion 9B of the stopper cylinder 9. There is. The giant magnetostrictive rod 11 is constantly urged upward by the setting spring 5 via the spring bearing 3 and is positioned between the spring bearing 3 and the stopper cylinder 9 in the axial direction of the coil bobbin 6.

Reference numeral 12 denotes a thick disk-shaped lid body provided on the upper end side in the casing 1, and the lid body 12 is integrally formed with a columnar projection 12A projecting downward from the center of the lower surface. A pair of seal member insertion holes 12B, 12B are formed in the upward and downward directions so as to be spaced radially outward of the protrusion 12A. The protrusion 12A of the lid body 12 is fitted in the stopper insertion hole 6A of the coil bobbin 6 on the upper side, and the gas filling portion 10 is closed after the gas G is filled. The outer peripheral side of the lid body 12 is sandwiched between the caulking portion 1A and the annular step portion 1C of the casing 1 and fixed to the upper end side of the casing 1. In addition, the small-diameter cylindrical seal members 13 are inserted into the seal member insertion holes 12B of the lid body 12, and the terminal pins 8 face upward to the outside of the casing 1 through the seal members 13. It is protruding.

The giant magnetostrictive actuator according to the present embodiment has the above-mentioned configuration, and its operation will be described below.

First, when an injection pulse is fed to the electromagnetic coil 7 as shown by a characteristic line 14 in FIG. 2 and a magnetic field is applied to the giant magnetostrictive rod 11 by the electromagnetic coil 7, the giant magnetostrictive rod 11 produces a magnetic field at this time. The valve body 4 which is stretched and deformed according to the strength and fixed to the spring bearing 3 against the set spring 5 is displaced downward with a lift amount as shown by a characteristic line 15 shown in FIG. Then, the valve body 4 is driven downward by the extension deformation of the giant magnetostrictive rod 11, and the valve portion 4B is seated on and off the valve seat 2B to perform the opening and closing operations.

Here, 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 inside of the combustion chamber (not shown) is Even when pressure acts on the valve body 4 from the outside, the valve body 4 is pressed against the valve seat 2B and continues to be seated, and the valve body 4 is inadvertently opened until the electromagnetic coil 7 is supplied with an injection pulse. Can be prevented. However, when it is affected by heat from the combustion chamber or heat generated by the electromagnetic coil 7, the giant magnetostrictive rod 11 thermally expands and expands in the axial direction.

In this case, when the upper end side end surface 11 A of the giant magnetostrictive rod 11 is replaced with the stopper portion 9 B of the stopper tube 9 and fixed to the casing 1 via the lid or the like as described in the prior art, Since the coefficient of thermal expansion α is larger than the coefficient of thermal expansion of the casing 1, the upward expansion of the giant magnetostrictive rod 11 is restricted by the thermal expansion, and the giant magnetostrictive rod 11 expands downward. Then, when the giant magnetostrictive rod 11 thermally expands downward, the valve body 4 is pushed downward by this, and in the worst case, the valve portion 4B of the valve body 4 separates from the valve seat 2B and seal failure occurs. Cause of. Further, when the injection pulse is supplied to the electromagnetic coil 7 to expand and deform the giant magnetostrictive rod 11, the amount of thermal expansion of the giant magnetostrictive rod 11 is added to the amount of expansion, and the valve body 4 is shown by a virtual line in FIG. The characteristic of the lift amount changes as shown by the characteristic line 16.

Therefore, in the present embodiment, a gas sealing portion 10 as a cylindrical space is provided between the coil bobbin 6 and the stopper cylinder 9 that houses the giant magnetostrictive rod 11, and the gas sealing portion 10 is provided with the gas sealing portion 10. Is filled with a gas G having a heat insulating property such as air, nitrogen, carbon dioxide, etc., and even if the electromagnetic coil 7 generates heat due to energization, the heat can be blocked by the gas G enclosed in the gas enclosure 10 and thus the giant magnetostriction is generated. The heat from the electromagnetic coil 7 is prevented from being transmitted to the rod 11.

Thus, even if the electromagnetic coil 7 generates heat while using the giant magnetostrictive actuator, this heat is prevented from being transmitted to the giant magnetostrictive rod 11 and raising the temperature of the giant magnetostrictive rod 11. The length dimension of the giant magnetostrictive rod 11 changes due to thermal expansion, and the valve body 4 provided at the tip of the spring bearing 3 is inadvertently separated from the valve seat to cause sealing failure. It can be prevented.

Further, in this embodiment, the stopper tube 9 is formed in a tubular shape from a non-magnetic material having a coefficient of thermal expansion close to the coefficient of thermal expansion α of the giant magnetostrictive rod 11, and the stopper tube 9 has an overall length exceeding 100 mm. The upper end side end surface 11A of the super magnetostrictive rod 11 which is formed so as to correspond to the total length L of the magnetostrictive rod 11 and is housed in the stopper cylinder 9 is pressed against the stopper portion 9B, and the supermagnetostrictive rod 11 is set in the casing 1. It is positioned in the axial direction. As a result, when the giant magnetostrictive rod 11 thermally expands even slightly due to the influence of heat from the outside, the tubular portion 9A of the stopper cylinder 9 also thermally expands in the same manner at this time, so that the stopper portion 9B of the stopper cylinder 9 is expanded. On the side, the thermal expansion of the giant magnetostrictive rod 11 can be absorbed and offset, and the upward extension due to the thermal expansion of the giant magnetostrictive rod 11 can be allowed and the downward extension can be prevented. The spring load of the setting spring 5 can be prevented from changing due to the thermal expansion of the giant magnetostrictive rod 11, and a constant initial load can be continuously applied to the giant magnetostrictive rod 11.

Therefore, according to the present embodiment, the thermal expansion of the giant magnetostrictive rod 11 can be effectively suppressed, and even if the giant magnetostrictive rod 11 thermally expands even a little, the giant magnetostrictive strain due to this thermal expansion will occur. The dimensional change of the rod 11 can be offset by the dimensional change of the stopper cylinder 9 due to the thermal expansion, and the change of the lift amount characteristic of the valve body 4 can be reliably prevented. It is possible to drive with a normal lift amount, and it is possible to solve the problem of defective sealing between the valve seat 2B and the valve portion 4B.

Next, FIG. 3 shows a second embodiment of the present invention, which is characterized in that the giant magnetostrictive actuator is applied to an inward opening type injection valve and the stopper cylinder is made of a ceramic material. There is something I did. 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 denotes 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. Although the caulking portion 21A and the annular step portions 21B and 21C are provided on the upper end side of the casing 21, the casing 21 has a tubular fitting portion 21D on the lower side of the annular step portion 21C.

Reference numeral 22 denotes a cylindrical tubular body with a lid fitted and fixed to the inner peripheral side of the fitting portion 21D of the casing 21, and the lower end side of the valve body 22 is closed by a valve seat member 23. At 23, a fuel injection port 23B having a valve seat 23A inside is formed. Further, a through hole 22B is formed in the center of the lid portion 22A in the valve body 22, and a valve shaft 26A described later is slidably inserted into the through hole 22B via a cylindrical seal member 24. There is. A fuel inflow hole 25 is bored in the valve body 22 in the radial direction. The inflow hole 25 allows fuel from a fuel pump (neither is 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, and the valve body 26 slides in a through hole 22 B of the valve body 22 via a seal member 24. It is configured by a valve shaft 26A that can be inserted and fitted, and a poppet-type valve portion 26B that is integrally formed on the lower end side of the valve shaft 26A and that is seated on and off the valve seat 23A of the valve seat member 23. Further, a spring bearing 27 made of an annular flat plate is provided between the valve shaft 26A of the valve body 26 and the valve portion 26B, and the valve body is provided between the spring bearing 27 and the lid portion 22A of the valve body 22. A valve spring 28 is provided as a biasing means for constantly biasing the valve 26 in the valve closing direction. Communication holes 27A, 27A, ... Are bored in the spring receiver 27 at predetermined intervals in the circumferential direction, and the communication holes 27A allow the valve body 22 to communicate with the valve seat member 23 at all times.

Reference numeral 29 denotes an annular lid body fixed to the upper end side of the casing 21. The lid body 29 has a through hole 29A at the center thereof, and a seal member insertion hole 2 is provided outside the through hole 29A in the radial direction. 9B and 29B are provided in the upper and lower directions, respectively. Then, small-diameter cylindrical seal members 30, 30 are mounted in the respective seal member insertion holes 29B to prevent rainwater and the like from the outside from entering the coil bobbin 6 from around the terminal pins 31. . The lid 29 is caulked and fixed to the annular step portion 21B of the casing 21 by a caulking portion 21A.

Reference numeral 32 denotes a stopper tube inserted into the stopper insertion hole 6 A of the coil bobbin 6 together with the giant magnetostrictive rod 33. The stopper tube 32 is formed of a ceramic material having a large heat insulating effect into an elongated tube shape, and A tubular portion 32A that extends in the stopper insertion hole 6A in the axial direction, a stopper portion 32B that closes the upper end side of the tubular portion 32A, and a flange-shaped flange portion 32C that is provided on the lower end side of the tubular portion 32A. It is composed of and. The giant magnetostrictive rod 33 has substantially the same configuration as the giant magnetostrictive rod 11 described in the first embodiment.

Reference numeral 34 denotes a displacement transmission mechanism that transmits the displacement of the giant magnetostrictive rod 33 to the valve body 26. The displacement transmission mechanism 34 is slidably fitted in the fitting portion 21C of the casing 21, A disc-shaped sliding plate 35 integrally provided with boss portions 35A and 35B on both upper and lower sides, and a bracket 36 projecting radially outward from the boss portion 35B of the sliding plate 35. , A transmission link 37 that is pin-connected to the bracket 36 and hangs downward, and is formed by bending in a substantially V-shape, and rotates via a pin 38 to the fitting portion 21D of the casing 21. The rotation link 39 is pin-combined so that the rotation link 39 has one end pinned to the transmission link 37 and the other end pinned to the valve shaft 26A of the valve body 26.

Here, the boss portion 35 A of the sliding plate 35 is inserted into the tubular portion 32 A of the stopper tube 32 from below, and when the stopper tube 32 is fixed in the casing 21, It is pressed against the end face on the lower end side with a predetermined load. Then, when the electromagnetic coil 7 is energized and the giant magnetostrictive rod 33 is expanded and deformed, the lower end side of the giant magnetostrictive rod 33 is displaced downward in the stopper tube 32 and slides in the fitting portion 21 D of the casing 21. Since the moving plate 35 is pushed downward together with the transmission link 37, the rotating link 39 is rotated in the direction of arrow A, and the valve body 26 is opened against the valve spring 28 with a desired lift amount. Let

Thus, in this embodiment having the above-described structure, it is possible to obtain substantially the same effects as the first embodiment. However, particularly in this embodiment, the giant magnetostrictive rod 33 and the coil bobbin 6 are connected. By providing the stopper tube 32 made of a ceramic material having a large heat insulating effect between the coils, the giant magnetostrictive rod 33 can be stably supported in the coil bobbin 6, and the mechanical strength of the giant magnetostrictive actuator is improved. In addition, the expansion / contraction of the giant magnetostrictive rod 33 is transmitted to the inward opening type valve body 26 via the displacement transmitting mechanism 34, thereby opening and closing the valve body 26 with a large lift amount. Therefore, the giant magnetostrictive rod 33 made of an expensive giant magnetostrictive material can be formed in a short length.

Next, FIG. 4 shows a third embodiment of the present invention, which is characterized in that the giant magnetostrictive actuator opens and closes the valve body of the intake valve or the exhaust valve of the engine. In addition to being used as an actuator, the coil bobbin is made of a heat insulating material such as ceramic.

In the figure, reference numeral 41 denotes a cylindrical casing formed of a magnetic material such as electromagnetic stainless steel in a stepped cylindrical shape. The casing 41 has caulked portions 41A and 41B at both upper and lower ends thereof, and the casing is On the inner peripheral side of 41, annular stepped portions 41C, 41D, 41E are formed between the crimped portions 41A, 41B with a predetermined distance in the axial direction.

Reference numeral 42 denotes a rod guide provided on the inner circumference of the lower end side of the casing 41. The rod guide 42 is made of a material having high wear resistance and is formed in a relatively thick disc shape. A rod insertion hole 42A is formed. The rod guide 42 is caulked and fixed between the caulking portion 41B of the casing 41 and the annular step portion 41E, and closes the lower end side of the casing 41.

Reference numeral 43 denotes a push rod as a drive target provided on the lower end side of the casing 41, and the push rod 43 is slidable in the casing 41 between the annular step portions 41 D and 41 E of the casing 41. The inserted disc-shaped spring receiving portion 43A, the cylindrical boss portion 43B protruding downward from the center of the lower surface of the spring receiving portion 43A, and the downward extending from the lower end side of the boss portion 43B. And a small diameter shaft portion 43C protruding outside the casing 41 through the rod insertion hole 42A of the rod guide 42, and a shallow recess 43D is formed in the center of the upper surface side of the spring receiving portion 43A. . A lower end of a giant magnetostrictive rod 48, which will be described later, is fitted and attached in the recess 43D of the push rod 43.

Reference numeral 44 denotes a setting spring as an urging means arranged around the boss portion 43B of the push rod 43 and arranged between the spring receiving portion 43A and the rod guide 42. The giant magnetostrictive rod 48 is constantly urged upward through the spring bearing portion 43A of the rod 43 to apply an initial load to the giant magnetostrictive rod 48. Here, a valve body (not shown) of, for example, an intake valve or an exhaust valve of an automobile engine is attached to the tip of the shaft portion 43C of the push rod 43, and the valve body opens when the giant magnetostrictive rod 48 expands or contracts. The valve is closed.

Reference numeral 45 denotes a stepped cylindrical coil bobbin disposed in the casing 41. The coil bobbin 45 is formed in a stepped cylindrical shape by a Lamic material or the like having a large heat insulating property, and the inside of the coil bobbin 45 will be described later. The sliding hole 45A holds the giant magnetostrictive rod 48.

Reference numeral 46 denotes an electromagnetic coil wound around the coil bobbin 45. The electromagnetic coil 46 is connected to terminal pins 47, 47 provided upright on the upper end side of the coil bobbin 45, and is excited by energization from the outside. Generate a magnetic field. Then, the electromagnetic coil 46 applies a magnetic field to the giant magnetostrictive rod 48 to extend and deform the giant magnetostrictive rod 48 in the axial direction and drive the push rod 43 in the valve opening direction of the valve body.

Reference numeral 48 denotes a giant magnetostrictive rod inserted into the sliding hole 45 A of the coil bobbin 45. The giant magnetostrictive rod 48 is made of the same giant magnetostrictive material as the giant magnetostrictive rods 11 and 33 described in the above embodiments. The coil bobbin 45 has a diameter corresponding to the sliding hole 45A. The end surface of the giant magnetostrictive rod 48 on the lower end side projects downward from the sliding hole 45A of the coil bobbin 45 and is fitted into the recess 43D of the push rod 43. The giant magnetostrictive rod 48 is constantly urged upward by the setting spring 44 via the push rod 43, and is positioned in the axial direction of the coil bobbin 45 between the push rod 43 and a stopper 49 described later.

Reference numeral 49 denotes a stopper fitted inside the upper end of the casing 41 and positioned on the annular step portion 41C. The stopper 49 is made of a magnetic material in the shape of a thick disk, and the stopper 49 At the center of the lower surface, a cylindrical projection 49A that projects downward is integrally formed. Here, the stopper 49 is fitted in the casing 41, the outer peripheral side of the lower surface thereof is brought into contact with the annular step portion 41C of the casing 41, and the protrusion 49A is fitted in the sliding hole 45A of the coil bobbin 45. The tip of the projection 49A abuts on the end surface of the giant magnetostrictive rod 48, whereby the giant magnetostrictive rod 48 is axially positioned in the coil bobbin 45. Further, a pair of terminal pin insertion holes 49B, 49B are formed in the stopper 49 so as to be spaced radially outward from the projection 49A, and the terminal pin insertion holes 49B are formed in the upward and downward directions. Each terminal pin 47 is inserted through each insulator 50.

Reference numeral 51 denotes a thick disk-shaped lid body sandwiched between the caulking portion 41 A and the stopper 49 on the upper end side in the casing 41, and the lid body 51 has a center portion of the lid body 51. Are spaced apart from each other in the radial direction, and seal member insertion holes 51B and 51B are formed in the upper and lower directions, respectively, the respective terminal pin insertion holes 49B of the stopper 49 being aligned with the center thereof. Then, each small-diameter cylindrical seal member 52 is inserted into each seal member insertion hole 51B, and each terminal pin 47 is projected upward to the outside of the casing 41 via each seal member 52. .

Although the present embodiment configured as described above can obtain substantially the same operation and effect as each of the above-described embodiments, particularly in this embodiment, the coil bobbin 45 around which the electromagnetic coil 46 is wound is large. A giant magnetostrictive rod 48, which is made of a ceramic material having a heat insulating effect, is disposed in the sliding hole 45A of the coil bobbin 45 and has a diameter corresponding to the sliding hole 45A. Therefore, heat insulation between the electromagnetic coil 46 and the super magnetostrictive rod 48 can be performed only by interposing the coil bobbin 45 between the electromagnetic coil 46 and the super magnetostrictive rod 48. The push rod 43 can be driven with a large displacement by efficiently applying a magnetic field to the magnetostrictive rod 48.

In each of the embodiments, the case where the giant magnetostrictive actuator is used as an actuator for driving the valve body of the giant magnetostrictive injection valve or the intake (exhaust) air valve has been described as an example. However, the present invention is not limited to this, and may be applied to, for example, a disc brake or the like. In this case, if the expansion / contraction deformation of the giant magnetostrictive rod is transmitted to the friction pad to apply the braking force to the disc. Good.

[0055]

[Effect of device]

 As described above in detail, according to the present invention, the heat insulating means for blocking the heat from the electromagnetic coil from reaching the giant magnetostrictive rod is provided between the giant magnetostrictive rod and the electromagnetic coil. Even if the heat is generated by the heat, the heat that tries to transfer from the electromagnetic coil to the giant magnetostrictive rod is blocked by the heat insulating means, so that the length dimension in the axial direction of the giant magnetostrictive rod can be prevented from changing due to thermal expansion. The object can be driven stably, and the reliability of the giant magnetostrictive actuator can be improved.

If the coil bobbin is made of a heat insulating material, the coil bobbin can effectively insulate the electromagnetic coil from the giant magnetostrictive rod, and a heat insulating material is interposed between them. Therefore, it is not necessary to separately provide a large space, so that it is possible to efficiently apply a magnetic field from the electromagnetic coil to the giant magnetostrictive rod to give a large displacement to the driven object.

[Brief description of drawings]

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

FIG. 2 is a characteristic diagram showing an injection pulse and a valve lift amount.

FIG. 3 is a longitudinal sectional view showing an inward opening type giant magnetostrictive injection valve according to a second embodiment.

FIG. 4 is a vertical sectional view showing a giant magnetostrictive actuator according to a third embodiment.

[Explanation of symbols]

 1, 21, 41 Casing 2, 23 Valve seat member 2A, 23B Injection port 2B, 23A Valve seat 3,27 Spring receiver 4,26 Valve body (object to be driven) 7,46 Electromagnetic coil 10 Gas injection part 11, 33, 48 Giant Magnetostrictive Rod 32 Stopper Cylinder (Adiabatic Means) 34 Displacement Transmission Mechanism 38 Pin 39 Pivoting Link 43 Push Rod (Drive Object) 45 Coil Bobbin G Gas (Adiabatic Means)

Claims (2)

[Scope of utility model registration request] 1. A tubular casing, and a magnetic field applied to drive a drive target provided at one end of the casing extending in the axial direction of the casing and provided inside the casing. A giant magnetostrictive rod that expands and contracts in the axial direction,
A giant magnetostrictive actuator comprising: an electromagnetic coil provided around the giant magnetostrictive rod in the casing and applying a magnetic field to the giant magnetostrictive rod by being energized from the outside, wherein the giant magnetostrictive rod and the electromagnetic coil are provided. A giant magnetostrictive actuator characterized in that heat insulating means for blocking heat from the electromagnetic coil from reaching the giant magnetostrictive rod is provided between and. 2. A tubular casing, and a magnetic field applied to drive an object to be driven which is provided inside the casing and extends in the axial direction of the casing. A giant magnetostrictive rod that expands and contracts in the axial direction,
A coil bobbin provided in the casing located around the giant magnetostrictive rod, and wound around the coil bobbin,
In a giant magnetostrictive actuator including an electromagnetic coil that applies a magnetic field to the giant magnetostrictive rod by being energized from the outside, the coil bobbin is formed of a heat insulating material that blocks heat from the electromagnetic coil from reaching the giant magnetostrictive rod. A giant magnetostrictive actuator characterized in that