JPH0652379U - Linear drive - Google Patents

Abstract

(57) [Summary] [Purpose] The object is to operate the linear drive device favorably over a long stroke while finely adjusting the thrust of the linear drive device with a simple configuration. [Structure] A thrust force proportional to the amount of current passing through the annular coil 2 is applied to the output shaft 5 via the annular magnet 8, and a movement resistance due to air viscosity in the hollow cylindrical cylinder 1 is applied to the output shaft 5. This allows the moving speed of the output shaft 5 to be finely adjusted.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a linear drive device used as a drive source for various devices and equipment.

[0002]

[Prior art]

 In general, various types of linear drive devices that perform linear reciprocating movement are used as drive sources for various devices and equipment. For example, in general production facilities, an air cylinder that can be easily positioned is often used as a linear drive device, and a reluctance type plunger or the like is used as one of magnetic type linear drive devices.

[0003]

[Problems to be solved by the device]

 However, this type of linear drive device is generally required to have a highly responsive operation, and in order to improve its characteristics, the speed of the movable part is detected to improve the stability of speed control and damping characteristics. Things are being done. For this reason, the device itself is complicated, and the control circuit and the like are also relatively complicated devices.

For example, the above-mentioned device using the air cylinder has an advantage that it can be downsized and high thrust can be obtained, but a complicated device is required to finely adjust the thrust. In addition, a magnetic plunger has problems such as slow movement, difficulty in adjusting thrust, and long stroke.

Therefore, an object of the present invention is to provide a linear drive device having a simple structure and capable of finely adjusting the thrust force and operating well over a long stroke.

[0006]

Means for Solving the Problems In order to achieve the above object, the present invention is a linear motor composed of a combination of a cylinder and a piston, and a hollow cylindrical cylinder having a predetermined axial length, An annular coil that extends in the axial direction while being wound around the inner wall surface of the hollow cylindrical cylinder, an output shaft that penetrates the hollow cylindrical cylinder in a reciprocating manner in the axial direction, and the output. It has a configuration including an annular magnet that is fixed on the shaft, is concentrically closely opposed to the inner peripheral side of the annular coil, and has different inner and outer peripheries.

[0007]

[Action]

 In the means having such a structure, a thrust force proportional to the amount of current passed through the annular coil is applied to the output shaft via the annular magnet, and the annular magnet and annular coil are placed close to each other. Since the air passage is narrowed, movement resistance due to air viscosity in the hollow cylindrical cylinder is given to the output shaft, and thereby the moving speed of the output shaft is finely adjusted. That is, when the piston is about to move, it is possible to adjust the movement of the piston by positively incorporating braking of a sudden movement by viscous resistance due to movement of air.

[0008]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment shown in FIGS. 1 and 2, a hollow cylindrical cylinder 1 made of a magnetic material has a predetermined axial length, and an annular coil 2 is provided on the inner wall surface of the hollow cylindrical cylinder 1. Is wrapped around the circumference. A support wall 3 is integrally formed in a thick-walled shape at one end (right end in the drawing) side of the hollow cylindrical cylinder 1, and the annular ring is formed so as to abut against the axially inner end surface of the support wall 3. The coil 2 is drawn in from the outside of the hollow cylindrical cylinder 1.

The annular coil 2 is wound around the inner wall surface of the hollow cylindrical cylinder 1 in a circumferential shape and extends on the axially opposite side (left side in the drawing). The extending end (the left end in the drawing) of the annular coil 2 is positionally regulated by abutting against the support wall 4 which is press-fitted and fixed in the hollow cylindrical cylinder 1 from the left side in the drawing. It is pulled out to the outside of the cylinder 1.

Inside the hollow cylindrical cylinder 1, an output shaft 5 made of a magnetic material is arranged so as to penetrate therethrough in the axial direction. Ball sliders 6 and 7 are fixed to both ends of the output shaft 5 in the axial direction. The ball sliders 6 and 7 are mounted on the inner circumferences of the support walls 3 and 4 of the hollow cylindrical cylinder 1 described above. The output shaft 5 is reciprocally held in the axial direction by being slidably supported on the wall surface in the axial direction.

Further, a hollow cylindrical annular magnet 8 is fixed at a substantially central portion of the output shaft 5 in the axial direction. The ring-shaped magnet 8 is arranged concentrically with the ring-shaped coil 2, and the ring-shaped magnet 8 faces the ring-shaped coil 2 in an annular shape so that the outer peripheral surface of the ring-shaped magnet 8 is close to the inner periphery of the ring-shaped coil 2 and maintains a slight gap. ing. The annular magnet 8 is magnetized with different poles on the inner and outer circumferences, is magnetized with N poles on the outer circumference side, and is magnetized with S poles on the inner circumference side.

Ring-shaped seal bodies 10 and 11 are attached to both ends of the support walls 3 and 4 provided in the hollow cylindrical cylinder 1, and these seal bodies 10 and 11 serve to prevent dust from the outside. It is configured so that air does not enter.

In such an embodiment, the magnetic flux loop A by the annular magnet 8 is formed as two magnetic fluxes that are symmetrical in the axial direction (the lateral direction in the drawing) with the center of the annular magnet 8 as a boundary. First, when the annular coil 2 is not energized, the flow of the magnetic flux loop A is substantially balanced in the axial direction, so that the annular magnet 8 and the output shaft 5 are placed in a stationary state. On the other hand, when the annular coil 2 is energized, a magnetic flux loop B is formed by the annular coil 2, so that the magnetic flux loop A causes the magnetic flux loop A of the annular magnet 8 to be unbalanced in the axial direction. The annular magnet 8 receives thrust in the axial direction, and the output shaft 5 is moved in the axial direction. The axial moving force (thrust) to the output shaft 5 is proportional to the amount of current supplied to the annular coil 2, and the action direction thereof is switched depending on the direction of electricity supplied to the annular coil 2.

This can be considered as the electromotive force of the annular coil 2 when the output shaft 5 is driven from the outside. That is, the number of turns of the annular coil 2 in the magnetic loop A on the right side of the annular magnet 8 and the number of turns of the annular coil 2 in the magnetic loop A on the left side of the illustration change depending on the position of the annular magnet 8. Moreover, the magnetic fluxes in the respective magnetic loops A are the same and the directions are opposite. Therefore, the voltage induced in the annular coil 2 appears in proportion to the moving direction and speed of the annular magnet 8.

As described above, the output shaft 5 is given a moving force in a predetermined direction through the annular magnet 8 in a predetermined amount. At this time, as shown by an arrow in FIG. The air in the duct 1 flows so as to pass through the minute gap formed on the outer peripheral portion of the annular magnet 8, whereby a movement resistance due to air viscosity is given to the output shaft 5. Since the viscous resistance of the air is proportional to the moving speed of the annular magnet 8, the moving resistance increases and the braking force increases as the output shaft 5 attempts to move faster. That is, the moving speed of the output shaft 5 moves at a speed at which the thrust generated by the applied current and the viscous resistance of the air are balanced, the sudden movement of the output shaft 5 is damped, and the moving speed of the output shaft 5 is reduced. It is designed to be finely adjusted.

On the other hand, when it is desired to keep the moving force of the output shaft 5 large and constant as in the case of grasping an object, the amount of current applied to the annular coil 2 may be increased, and therefore the moving speed of the output shaft 5 may be increased. Is easily controlled. Therefore, thrust control is possible with a simple circuit.

In the embodiment according to FIG. 4 in which the same components as those of the embodiment shown in FIG. 1 are indicated by the same reference numerals, an air path extending in the axial direction is provided in the magnet fixing portion of the output shaft 5. 5a is recessed in a groove shape extending in the axial direction. With this configuration, when the output shaft 5 moves, the air in the hollow cylindrical cylinder 1 flows through the air passages 5a as it goes through the minute gaps on the outer circumference of the annular magnet 8 and thereby flows. Movement resistance due to air viscosity is given to the output shaft 5, and the moving speed of the output shaft 5 is adjusted. By providing the air path 5a, the movement of the output shaft 5 becomes faster than in the case of FIG.

In the embodiment according to FIG. 5 in which the same components as those of the embodiment shown in FIG. 1 are indicated by the same reference numerals, the output shaft 25 has a long hollow shape formed by boring or pipes. The hollow pipe 20 is formed of a body, and a hollow pipe 20 is rotatably and closely inserted inside the hollow output shaft 25. The hollow pipe 20 is attached by press fitting or other means. The output shaft 25 and the hollow pipe 20 are provided with through holes 21, 21 and 22, 22 in axially opposite side portions of the annular magnet 8 so as to overlap in the axial direction, and the through holes 21, 22 do not overlap. Therefore, air is prevented from entering the output shaft 25. The area of the opening formed by the weight of these through holes 21, 21 and 22, 22 is changed by rotating the hollow pipe 20.

Further, a rotary shaft 23 extends from one end of the hollow pipe 20, and a knob 24 is attached to the extended end of the rotary shaft 21 from the outside of the output shaft 25. The knob 23 and the output shaft 25 are formed with an index (not shown) indicating the degree of weight of the through holes 21 and 22.

According to such an embodiment, when the output shaft 25 is moved, as shown by the arrow in FIG. It flows so as to pass through the hollow pipe 20 through the through hole 22 of the hollow pipe 20, whereby the movement resistance due to air viscosity is given to the output shaft 25, and the moving speed of the output shaft 25 is adjusted. At this time, if the hollow pipe 20 is rotated by turning the knob 23, the weight degree of the through holes 21, 21 and 22, 22, that is, the opening amount is changed, and the damping amount by air is easily adjusted. The moving speed of the output shaft 25 is variable.

[0021]

[Effect of device]

 As described above, the present invention applies a thrust force, which is proportional to the amount of current flowing to the annular coil, to the output shaft via the annular magnet, and at the same time, the movement resistance due to the air viscosity in the hollow cylindrical cylinder is applied to the output shaft. Since it is possible to finely adjust the moving speed of the output shaft, it is possible to satisfactorily operate over a long stroke while finely adjusting the thrust with a simple configuration.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the structure of a linear drive device according to a first embodiment of the present invention.

2 is a cross-sectional explanatory view taken along the line II-II in FIG.

FIG. 3 is a vertical cross-sectional explanatory view showing the braking action of the linear drive system in the embodiment shown in FIGS. 1 and 2.

FIG. 4 is a vertical cross-sectional explanatory view showing the structure of a linear drive device according to a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional explanatory view showing the structure of a linear drive device according to a third embodiment of the present invention.

[Explanation of symbols]

 1 Hollow cylindrical cylinder 2 Annular coil 5,25 Output shaft 8 Annular magnet

Claims (2)

[Scope of utility model registration request] 1. A hollow cylindrical cylinder having a predetermined axial length, an annular coil wound around the inner wall surface of the hollow cylindrical cylinder in a circumferential direction and extending in the axial direction, and in the hollow cylindrical cylinder. An output shaft penetrating reciprocally in the axial direction, and an annular magnet fixed to the output shaft so as to concentrically and closely face the inner peripheral side of the annular coil, and the inner and outer circumferences of which have different polarities. ,
A linear drive device comprising: 2. The linear drive device according to claim 1, wherein an air passage that straddles the annular magnet is provided on the output shaft, and a means for adjusting the size of the air passage is provided.