JPH0835729A - Supporting structure of movable shaft for linear motor - Google Patents

Abstract

PURPOSE:To realize the supporting structure of a movable shaft for a linear motor in which the horizontal rectilinear movement (reciprocation) of the shaft can be elastically stably supported accurately in a long term and the reliability and stability of the operation of a Starling refrigerator (linear motor) can be remarkably improved. CONSTITUTION:In a supporting structure for elastically supporting the movable shaft 17 of a linear motor 11 so as to linearly reciprocate it in its longitudinal axis direction, a plurality of bearings 31 having two torsion bars coupled integrally by a beam member are used to support the shaft by a both ends supporting type.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support structure for a movable shaft of a linear motor.

[0002]

2. Description of the Related Art In recent years, various electronic devices such as observation sensors mounted on spacecrafts such as artificial satellites have been rationalized.
A Stirling refrigerator is used for effective cooling, for example. For example, in a Stirling refrigerator driven by a voice coil type linear motor, the movable shaft of the linear motor is swirled as shown in FIG. A plurality of (three in the drawing) through slit portions 61 are elastically supported to the base side via a lightweight disc-shaped support member 63 formed by shifting the phase.

[0003]

However, due to the structure of the support member (through slit portion), the strength in the in-plane direction decreases as the deformed and supported state progresses, so that the movable shaft is always stable. It was quite difficult to support elastically. Therefore, it is an object of the present invention to realize a support structure that can favorably ensure straight-line stability in reciprocal movement of a movable shaft of a linear motor.

[0004]

In order to solve the above problems, a support structure for a movable shaft of a linear motor according to the present invention is configured so that the movable shaft of the linear motor can be linearly reciprocated in its longitudinal axis direction. In the support structure for elastically supporting the movable shaft, the movable shaft is supported in a double-sided manner by using a plurality of bearing portions formed of two torsion bars integrally connected by a beam member.

[0005]

When the movable shaft is linearly moved, the two torsion bars of each bearing portion elastically twist and deform through the beam members to stably support the movable shaft, so that the linear stability of the movable shaft is maintained high. To be done.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of essential parts showing a linear motor part in an example of a Stirling refrigerator to which the present invention is applied,
FIG. 2 is a perspective view of a main part of the bearing portion. As shown in FIG.
A so-called expansion section is arranged on the left side (not shown) of the so-called voice coil type linear motor section 11, and this expansion section slides inside the cylinder to define an expansion chamber in the cylinder. It comprises a piston and an outwardly projecting piston rod integrally connected to the piston.

On the opposite side of the linear motor section 11, that is, on the right side (not shown) of the linear motor section 11, a so-called balancer section for maintaining dynamic balance with the expansion section is arranged. It The balancer portion has a general balancer structure. For example, although not shown, a yoke movably supported with respect to the base side by a support spring portion formed by stacking hollow thin elastic discs and a yoke side surface. A ring-shaped magnet that is attached to the inner side of the peripheral groove formed in the magnet, and a coil that is fixed to the base side that is placed outside the magnet are used to reduce the size and weight of the active yoke type. It can consist of a balanced structure.

The illustrated linear motor section 11 has a movable shaft 17 integrally formed (or integrally connected) with a piston rod of an expansion section (not shown) and a base side through which the movable shaft 17 penetrates with a predetermined clearance. Fixed iron core 21 and iron core 21
It includes a cylindrical magnet 23 attached to the outer side of the circumferential groove formed on the side surface, and a coil 25 arranged inside the magnet 23, and the coil 25 includes a movable shaft 17 via a flange 27. Are integrally connected to.

Movable shaft 17 (coil 25, flange 27)
Is elastically supported by two bearing structures in the longitudinal direction so as to be linearly reciprocable in the longitudinal axis direction with respect to the base side. The bearing portion 31 as shown in FIG. 3 may be configured to have two (or a plurality of) symmetrically and evenly arranged and connected around the movable shaft.

Since all the bearing portions 31 have the same structure, only one of them will be described. As shown in FIG. 2, the bearing portion 31 is fixed on both sides by a bracket 33 fixed on the base side. Side torsion bar (bar-shaped spring body using torsion) 35, movable side torsion bar 39 supported on both sides by a bracket 37 fixed to the movable shaft 17, and both torsion bars positioned in parallel. And a long plate-shaped beam member 41 that is integrally connected.

In this embodiment having the above construction,
Since the movable shaft of the linear motor unit is configured to be supported in a double-sided manner by using a plurality of bearing portions composed of two torsion bars integrally connected by a beam member, the movable shaft moves straight in the horizontal direction ( (Reciprocating motion) can be supported elastically and stably for a long time with high accuracy, and thereby the reliability and stability of the operation of the Stirling refrigerator (linear motor unit) can be dramatically improved.

[0012]

As described above, according to the present invention, it is possible to reliably and stably secure the straightness of the movable shaft of the linear motor.

[Brief description of drawings]

FIG. 1 is a side view of a main part of an embodiment of the present invention.

FIG. 2 is a perspective view of a main part of a bearing portion.

FIG. 3 is a plan view of a conventional support member.

[Explanation of symbols]

 11 ... Linear motor part 17 ... Movable shaft 21 ... Iron core 23 ... Magnet 25 ... Coil 27 ... Flange 31 ... Bearing part 33 ... Bracket 35 ... (Fixed side) torsion bar 37 ... Bracket 39 ... (Movable side) torsion bar 41 ... Beam member

Claims (1)

[Claims] 1. A movable shaft (17) of a linear motor (11).
In a support structure for elastically supporting the rod so as to be capable of linearly reciprocating in the longitudinal axis direction, a bearing portion (two bearing bars (35, 39) integrally connected by a beam member (41) ( 31) A support structure for a movable shaft of a linear motor, characterized in that the movable shaft is supported in a double-sided manner by using a plurality of them.