JPH05103457A - Linear motor - Google Patents

Abstract

PURPOSE:To reduce the fluctuation of the traveling speed of the movable armature of a linear motor. CONSTITUTION:Magnetic shock absorbing members 15, which are provided with inclined faces by which the intervals with the magnetic poles 2 juxtaposed on a stator 1 (secondary yoke) widens gradually, are attached to both end faces in traveling direction of a movable armature (primary iron core), and the component is shifting direction of the magnetic attraction caused by leakage magnetic flux is made small by making the leakage magnetic flux from the magnetic poles 2 to the end faces of the primary iron core 3 incident on the inclined face of the magnetic shock absorbing member 15, thus the speed fluctuation, which occurs periodically separately for each pitch of the adjustment magnetic poles 2, is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor which performs linear motion and is capable of reducing speed fluctuations.

[0002]

2. Description of the Related Art A conventional example of a linear motor will be described with reference to FIG. In this figure, a large number of magnetic poles 2 having different polarities are alternately arranged side by side on a flat plate-like secondary yoke (stator) 1, and the cross-sectional shape of the magnetic poles 2 is different from the outer surface of the magnetic poles 2 with an appropriate gap. Comb-shaped primary cores (movable armatures) 3 are arranged to face each other in the parallel direction. The primary iron core 3 is provided with a large number of coils 4 which form a moving magnetic field in an inner groove facing the magnetic pole 2, and the primary magnetic core 3 can move in a parallel direction of the magnetic poles 2 at an appropriate speed by the interaction between the moving magnetic field and the magnetic poles 2 by the coils 4. It is like this.

[0003]

In the structure described above, a magnetic attraction force in the moving direction is generated by so-called leakage magnetic flux generated between the magnetic pole 2 and both end surfaces of the primary iron core 3 in the moving direction as indicated by the dotted arrow. The attraction force changes depending on the relative positional relationship between the end surface of the primary core 3 and the magnetic pole 2. Therefore, there is a drawback that the moving speed of the movable armature 3 periodically fluctuates for each pitch of the adjacent magnetic poles 2.

In order to eliminate the above-mentioned drawbacks, the present invention provides
An object of the present invention is to provide a linear motor capable of reducing the speed fluctuation of the movable armature.

[0005]

In order to achieve the above-mentioned object, the present invention has a movable armature (primary iron core) 3 provided in parallel on a stator (secondary yoke) on both end faces in the moving direction. A magnetic buffer member 15 with an inclined surface in which the gap with the magnetic pole 2 gradually increases is attached.

[0006]

The magnetic flux leaking from the magnetic pole 2 to the end surface of the primary iron core 3 enters from the inclined surface of the magnetic buffer member 15 and flows, and the magnetic attraction force generated in this inclined surface in the moving direction is explained in the conventional example. Since it is smaller than the above, the speed fluctuation of the movable armature 3 can be reduced.

[0007]

FIG. 1 shows an embodiment of the present invention.
Those denoted by the same reference numerals as are the same parts. In this figure, a large number of magnetic poles 2 having different polarities are alternately arranged side by side on a secondary side yoke (stator) 1, and a coil 4 that creates a moving magnetic field with an appropriate gap with the outer surface of the magnetic pole 2 is provided. Primary comb-shaped primary cores (movable armatures) 3 are arranged so as to oppose each other in the direction parallel to the magnetic poles 2. This primary iron core 3 can move at an appropriate speed in the parallel direction of the magnetic poles 2 due to the interaction of the moving magnetic field by the coils 4 and the magnetic poles 2, and the inclined surfaces where the gap between the magnetic poles 2 gradually widens on both end faces in the moving direction. Attached is a magnetic buffer member 15. This magnetic buffer member 1
Reference numeral 5 is made of a magnetic material, and the leakage magnetic flux from the magnetic pole 2 to the end surface portion of the primary iron core 3 in the moving direction enters and flows from the inclined surface of the magnetic buffer member 15 as indicated by the dotted arrow.

According to the above-described embodiment, the magnetic attraction force in the moving direction of the primary iron core 3 generated by the leakage magnetic flux is the leakage magnetic flux entering from the inclined surface of the magnetic buffer member 15 and the component force in the flow moving direction is explained in the conventional example. Since it is smaller than the above, the fluctuation of the moving speed of the movable armature 3 can be reduced.

[0009]

According to the present invention, in a linear motor, an inclined surface in which a gap between magnetic poles arranged in parallel on a stator (secondary yoke) is gradually widened on both end surfaces in the moving direction of a movable armature (primary iron core). Since the attached magnetic buffer member is attached,
The magnetic flux attracting force in the moving direction of the primary core due to the leakage magnetic flux can be reduced to reduce the speed fluctuation of the movable armature.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of the present invention.

FIG. 2 is a front view of a conventional example.

[Explanation of symbols]

 1 Secondary side yoke (stator) 2 Magnetic pole 3 Primary iron core (movable armature) 4 Coil 15 Magnetic buffer member

Claims (1)

[Claims] 1. A cross section in which a secondary side yoke (stator) in which a large number of magnetic poles having different polarities are alternately arranged side by side is arranged, and the outer surface of the magnetic pole is opposed to the outer surface of the magnetic pole with a proper gap and a coil is wound. In a linear motor having a comb-shaped primary core (movable armature) in the direction parallel to the magnetic poles, magnetic buffer members with inclined surfaces where the gap between the magnetic poles gradually expands are attached to both end faces in the moving direction of the primary core. A linear motor characterized by that.