JPH0327779A - Linear actuator - Google Patents

Abstract

PURPOSE:To lighten a movable element by winding a coil round a radial rib, which is provided on the outer peripheral of a shaft in the manner of projecting therefrom. CONSTITUTION:A linear actuator for leveling regulation, etc., is composed of a side yoke 1 provided with projecting collar parts 2, a permanent magnet 3, a magnetic circuit by a center yoke 4 and a movable element 5, which element 5 is formed when a coil 9 is wound round the outer peripheral of a bobbin 8 obtained by securing a cross rib 7 to the outer peripheral of a shaft 6. Further, the center yoke 4 is provided with a groove 10 in the position corresponding to that of said rib 7 so that the rib 7 is inserted into the groove.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a linear actuator suitable for use in chassis control actuators such as vehicle height adjustment actuators for automobiles, and in particular to small-sized linear actuators. lightweight,
It concerns linear actuators with high thrust and high response. [Prior art] Generally, when the carrying load of a car changes. The ground clearance of the vehicle body, that is, the vehicle height, changes, but if the range of load change is large or the support springs for the vehicle body are soft, the effect of the change in vehicle height is significant and may cause problems in driving the vehicle. obtain.
In order to reduce such changes in vehicle height. There is a way to make the support springs harder, that is, increase the spring constant, but this is not desirable because it makes the ride uncomfortable. For this reason, various methods have been proposed for attaching a vehicle height adjustment device to a suspension system of a vehicle body, a sitac absorber, or the like. Among such vehicle height adjustment devices, for example, shock absorbers with air springs have a structure in which a thick absorber is used as a support spring and an air spring is attached to the outside. [Problems to be Solved by the Invention] In the above-mentioned conventional vehicle height adjustment device, the actuator is actuated by a signal from the vehicle height detection sensor to supply and exhaust air into the SiG7 absorber and/or the air spring. A method that operates a regulating valve is relatively widely used. There are various types of actuators like this, but it is common to use a solenoid valve or a motor. For example, by driving the control rond attached to the piston rond that controls the SiM7 quad absorber using a rotary actuator with a built-in motor. Adjust the opening degree of the valve provided at the bottom of the piston rond (
A system in which the fluid passages are switched has been put into practical use (for example, see Japanese Utility Model Application Publication No. 37370/1983).
However, those using a rotary actuator have the problem that the opening degree of the regulating valve that supplies air, that is, the adjustment accuracy of the air flow rate, is insufficient, and the response is low (about 30 Hz). be. Furthermore, since the vehicle height adjustment device described above is attached to the suspension part of the vehicle body, it must be installed in at least four locations, and as a result, it is naturally required to be smaller and lighter. The problem is that some actuators do not meet these requirements. In other words, if we pursue high responsiveness, we will inevitably have to increase the size to achieve higher energy, but on the other hand, if we pursue smaller size and lighter weight, the responsiveness will decrease, which creates a contradiction.The emergence of an actuator that can satisfy both functions at the same time. is strongly desired. The purpose of the present invention is to solve the problems existing in the above conventional descriptions, and to provide a linear actuator that is small, lightweight, has high thrust, and has high responsiveness. [Means for Solving the Problems] In order to achieve the above object, in the present invention, a hollow cylinder is formed on the inner peripheral surface of the side yoke, which is formed of a ferromagnetic material in the shape of a hollow cylinder with a bottom. At the same time, a permanent magnet is fixedly magnetized. A magnetic circuit is formed by installing a center yoke made of ferromagnetic material at the center of the bottom of the side yoke and protruding coaxially with the side yoke. A linear actuator in which a movable element having a hollow cylindrical coil is disposed in an annular magnetic gap formed between the permanent magnet and the center yoke so as to be movable in the axial direction,
In addition to providing radial grooves in the center yoke. A technical measure was adopted in which a bobbin was inserted into this groove so that it could move freely in the axial direction, and a coil was wound around the outer circumference of this bobbin to secure the movable element. In addition, in the present invention, the lid member is fixed to the end portions of the side yokes and the center yoke. A bearing is fixed to the center of the side yoke and the lid member, respectively.
It can be constructed so that both ends of the shaft provided on the mover are inserted and supported through this bearing. [Function] With the above structure, the response of the mover can be greatly improved, and a linear actuator that is small, lightweight, and has high thrust can be made. In other words, energy can be directly transmitted to the mover. For example, by directly connecting an adjustment valve to the mover, it is possible to expect the effect of quickly supplying and discharging air for vehicle height adjustment. [
Embodiment] FIG. 1 is a vertical sectional view showing an embodiment of the present invention, and FIG.
It is a cross-sectional view taken along line A-A in the figure. 1 in both figures
is a side yoke, which is made of a ferromagnetic material such as steel and shaped like a hollow cylinder with a bottom, and has a collar 2 integrally protruding from the open end. A permanent magnet 3 is formed into a hollow cylindrical shape, is magnetized in the radial direction, and is fixed to the inner circumferential surface of the side yoke 1, for example, with an adhesive (not shown). Next 4
is a center yoke, which is formed in a cylindrical shape from the same ferromagnetic material as the side yoke 1, and is placed coaxially at the center of the bottom of the side yoke 1. and protrudes so as to be magnetically coupled to the side yoke 1. The above structure allows the magnetic circuit to be shaped. Next, 5 is a movable element, which is formed by winding a coil 9 around the outer periphery of a bobbin 8, which has a cross-shaped rib 7 fixed to the outer periphery of a shaft 6. In addition, the center yoke 4. At a position corresponding to the rib 7 that holds the movable element 5. A groove 10 having a width slightly larger than the width of the rib 7 is provided. Then, the coil 9 of the mover 5. in the annular magnetic gap formed by the permanent magnet 3 and the center yoke 4.
and a lip 7 are respectively interposed in the groove 10, and the movable element 5 is formed to be movable in the axial direction. Next, 1l is the lid member. For example, it is made of a structural material such as a steel plate, and is formed to correspond to the planar contour shape of the open end of the side yoke 1.
Reference numeral 12 denotes a mounting hole, which is bored so as to pass through the collar 2 of the side yoke 1 and the lid member 11. Bearings 13 and 14 are fitted into the center of the side yoke 1 and the lid member 11, and support both ends of the shaft 6 that supports the movable element 5. 15 is a screw hole. Drill into the open end of shaft 6. For example, a rond (not shown) for operating a regulating valve can be connected. 16 is a terminal cover. Hold the terminal l7 connected to the winding end of the coil 9. Due to the above structure. If the coil 9 that constitutes the movable element 5 is energized in the forward and reverse directions, the coil 9, that is, the movable element 5, can be moved in the axial direction according to Flegong's left-hand rule. In this case, the rib 7 moves within the groove 10. The mover 5 does not rotate around the axis 6. Therefore axis 6
The adjustment valve can be operated via the adjustment valve operation iron connected to the slotted hole L5 provided in the vehicle, allowing air to be quickly supplied and discharged for vehicle height adjustment. In Figures 1 and 2, the inner and outer diameter dimensions of the side yoke l are 50 ua and 60 m, respectively, and the axial depth dimension is 32 mm.
It is formed into a cabinet with inner and outer diameters of 42 m and 50 m, respectively. Nd-F with an axial length of 30 mm
Permanent magnet 3 made of e-B material (Hitachi Metals Hl2
7SV) was fixed, and a movable element 5 having a coil 9 attached to the outer periphery of a bobbin 8 made of a material equivalent to A5056 was interposed to assemble a linear actuator. In this linear actuator, the weight of the mover 5 is 40g, and the thrust for one effective stroke of 3ms+ is 4kg when the coil 9 is at 20°C and DC 12V and 2.5A are input.
It showed f. The response time is 110Hz (9 msec
), and confirmed that it has significantly higher responsiveness than conventional vehicle height adjustment actuators.

In this example, we have described an example of an actuator for adjusting the vehicle height, but this example is for changing the spring constant. Of course, it can also be used as an actuator for other chassis control such as damping force switching. [Effects of the Invention] The present invention has the structure and operation as described above.
The following effects can be expected: (1) The coil is wound around radial ribs protruding from the outer periphery of the shaft. The weight of the mover can be significantly reduced. (2) By reducing the weight of the mover! It has a high conversion efficiency of gas energy into mechanical energy and can achieve high thrust. (3) Furthermore, since the inertia of the mover is small, responsiveness can be greatly improved.

[Brief explanation of drawings]

The first drawing is a vertical cross-sectional view showing an embodiment of the present invention, and the second drawing is a vertical cross-sectional view showing an embodiment of the present invention.
It is a cross-sectional view taken along line A-A in the figure. l: side yoke, 3: permanent magnet, 4: center yoke, 5: mover.
8: bobbin, 9: coil.

Claims (3)

[Claims] (1) A permanent magnet formed in the shape of a hollow cylinder and magnetized in the radial direction is fixed to the inner peripheral surface of the side yoke, which is formed in the shape of a hollow cylinder with a bottom from a ferromagnetic material, and a permanent magnet is fixed to the inner peripheral surface of the side yoke, which is formed in the shape of a hollow cylinder with a bottom, using a ferromagnetic material. A center yoke made of a magnetic material is protruded coaxially with a side yoke to form a magnetic circuit, and a hollow cylindrical coil is formed in an annular magnetic gap formed between the permanent magnet and the center yoke. In a linear actuator in which a movable element having a movable element is disposed so as to be movable in the axial direction, a radial groove is provided in the center yoke, a bobbin is disposed in the groove so as to be movable in the axial direction, and a coil is disposed around the outer periphery of the bobbin. A linear actuator characterized in that a movable element is formed by winding. (2) A cover member is fixed to the ends of the side yoke and the center yoke, and a bearing is fixed to the center of each side yoke and the cover member, and both ends of the shaft provided on the mover are fitted through the bearing. The linear actuator according to claim 1, wherein the linear actuator is inserted and supported. (3) The linear actuator according to claim (2), wherein the lid member is made of a ferromagnetic material.