JPH10285901A - Linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain effective thrust at a higher value by reducing the frictional resistance, generated by magnetic attraction force, of a directacting means and to improve the efficiency obtained by dividing the effective thrust by electromagnetic thrust. SOLUTION: A movable element 2, provided in such a way as to be movable keeping a gap G with a direct-acting means 3, is arranged against a stator 1 extending in a propelled direction. Permanent magnets 1a, with N and S poles arranged alternately in the direction toward the gap G, are mounted on the stator 1 and an armature coil 2a is wound onto the movable element 2, which is propelled by receiving electromagnetic thrust from the stator 1. The direct-acting means 3 is made up of rails 3a on the frame 4 on which the stator 1 is fixed and wheels 3b of a movable element truck 5 on which the movable element 2 is mounted. A reducing means 10 comprising a permanent magnet 11 and a magnetic material 12 is arranged so that they attract each other in the direction of reducing the magnetic attraction force by the stator 1. The magnetic material 12, one side of the reducing means 10, is extended onto the bottom frame 4a of the stator 1 side, while the permanent magnet 12, another side of the reducing means 10, is provided on the movable element 2 side via a mounting plate 5a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC, induction or synchronous linear motor. The case of a synchronous linear motor will be described below.

[0002]

2. Description of the Related Art In a conventional example shown in FIG. 3, a movable element 2 which is movable with a gap G kept by a linear motion means 3 is arranged on a stator 1 which extends in a propulsion direction perpendicular to the plane of the drawing. I do. A plurality of permanent magnets 1a in which N poles and S poles are alternately arranged in the gap G direction are attached to the stator 1, and the armature coil 2a is wound around the mover 2. The mover 2 is propelled by receiving electromagnetic thrust from the stator 1. The armature coil 2a of the mover 2 is connected to the coil end 2b, and is supplied with electric power from a cable (not shown) that can expand and contract in the propulsion direction.

The linear motion means 3 for enabling the mover 2 to move while maintaining the gap G is a rail 3a of a frame 4 on which the stator 1 is mounted.
And the wheels 3b of the mover table 5 on which the mover 2 is mounted. The frame 4 includes a lower frame 4a, a horizontal frame 4b, and an upper frame 4c.
The rail 3a is fixed to the attachment 4d of the upper frame 4c. Note that FIG. 2 of the first embodiment can also be applied to FIG.

[0004]

When the mover 2 receives electromagnetic thrust from the stator 1, the mover 2 receives a magnetic attraction force in a direction perpendicular to the surface of the stator 1. The magnetic attraction force is several times to about ten times the electromagnetic thrust, and generates frictional resistance of the linear motion means 3 to reduce the effective thrust of the linear motor. In addition,
In the case of a rotating electric machine, the magnetic attraction force on the periphery does not reduce the rotating force because it is balanced with the axis, and the movable element 2 of the linear motor
When two pairs of the stator 1 and the stator 1 are arranged back to back,
The magnetic attraction force balances back to back and does not reduce effective thrust.

The effective thrust Fy in the case where the magnetic attraction generates frictional resistance of the linear motion means to reduce the effective thrust of the linear motor is expressed by the following equation. Fy = Ft− (Ms · g + Fm) μ where Ft: electromagnetic thrust Ms: mass on the mover side, negative value in the case shown in the figure g: acceleration of gravity Fm: magnetic attraction force μ: friction coefficient of linear motion means It is an object of the present invention to provide a linear motor capable of maintaining a high effective thrust by reducing the frictional resistance of a linear motion means that generates a magnetic attraction force and improving the efficiency obtained by dividing the effective thrust by an electromagnetic thrust. is there.

[0006]

According to the linear motor of the present invention, a movable member is provided on a stator extending in the direction of propulsion, the movable member being movable with a gap maintained by a linear motion means. One of the reducing means composed of a permanent magnet and a magnetic material that attracts in the direction of reducing the force is extended to the stator side, and the other is provided to the mover side.

According to the linear motor of the present invention, the reducing means attracts each other in the direction of reducing the magnetic attraction force between the stator and the movable element, so that the frictional resistance of the linear motion means generating the magnetic attraction force is reduced. To maintain the effective thrust at a high value. The efficiency obtained by dividing the effective thrust by the electromagnetic thrust is improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. In the first embodiment shown in FIGS. 1 and 2, the same parts as those in the conventional example will be described first. A movable element 2 that is movable by a linear motion means 3 while maintaining a gap G is disposed on a stator 1 that extends in a propulsion direction perpendicular to the plane of FIG. A plurality of permanent magnets 1a in which N poles and S poles are alternately arranged in the gap G direction are attached to the stator 1, and the armature coil 2a is wound around the mover 2. The mover 2 is propelled by receiving electromagnetic thrust from the stator 1. The armature coil 2a of the mover 2 is connected to the coil end 2b, and is supplied with electric power from a cable (not shown) that can expand and contract in the propulsion direction.

The linear motion means 3 for allowing the mover 2 to move while maintaining the gap G is a rail 3a of a frame 4 on which the stator 1 is mounted.
And the wheels 3b of the mover table 5 on which the mover 2 is mounted. The frame 4 includes a lower frame 4a, a horizontal frame 4b, and an upper frame 4c.
The rail 3a is fixed to the attachment 4d of the upper frame 4c. FIG.
Shows the armature coil 2a only on one salient pole 2p of the mover 2, and omits the illustration of the armature coil 2a on the other salient pole 2p. The salient pole 2p made of a laminated iron core is embedded in the yoke 2y. A state is shown in which a plurality of permanent magnets 1a in which N poles and S poles are alternately arranged in a gap G direction are attached to a stator 1 extending in the propulsion direction.

As a feature of the first embodiment, as shown in FIG. 1, a reducing means 10 comprising a permanent magnet 11 and a magnetic body 12 is arranged so as to be attracted to each other in a direction for reducing the magnetic attraction of the stator 1. I do. One magnetic body 12 of the reducing means 10 is extended to the lower frame 4a on the stator 1 side, and the other permanent magnet 12 of the reducing means 10 is provided on the movable element 2 side via the mounting plate 5a.

According to the first embodiment, the permanent magnet 11 and the magnetic body 12 forming the reducing means 10 are composed of the stator 1 and the movable element 2.
Are attracted to each other in a direction to reduce the magnetic attractive force Fm. For this reason, the frictional resistance [(Ms · g + Fm) μ in the previous equation] generated by the magnetic attraction force Fm is reduced with respect to the rail 3a and the wheels 3b forming the linear motion means 3 to increase the effective thrust Fy to a high value. To maintain. Effective thrust Fy is converted to electromagnetic thrust Ft
The efficiency divided by is improved.

The linear motion means 3 may be replaced with a sliding pair or a linear bearing using a large number of hard balls, instead of the rail and the wheels. Instead of a telescopic cable for supplying electric power to the armature coil 2a, an overhead wire and a current collector may be used. Further, the frame 4 and the mover stand 5 are not essential, and the stator 1 and the mover 2 may be directly mounted on a fixed stand and a moving body of a partner machine requiring a linear motor. Then, the linear motion means 3 can be attached to the fixed base and the moving body. Mitigation measures 1
0 is provided on the mover 2 side, and the reducing means 1
The other permanent magnet 12 may be extended to the stator 1, but the cost of the extended permanent magnet 12 is increased due to a large amount of use.

[0013]

According to the linear motor of the present invention, the reducing means reduces the frictional resistance of the linear motion means for generating the magnetic attraction force, maintains the effective thrust at a high value, and divides the effective thrust by the electromagnetic thrust. This has the effect of improving the efficiency achieved.

[Brief description of the drawings]

FIG. 1 is a front view of a first embodiment.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a front view of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Stator 1a Permanent magnet 2 Mover 2a Armature coil 2p Salient pole 2y Yoke 3 Linear motion means 3a Rail 3b Wheel 4 Frame 5 Mover table 10 Reduction means 11 Permanent magnet 12 Magnetic body G Air gap

Claims (1)

[Claims] 1. A permanent magnet which is provided on a stator extending in a propulsion direction and is movable by a linear motion means while maintaining a gap, and attracts in a direction to reduce a magnetic attraction force of the stator. A linear motor characterized in that one of the reducing means, comprising a magnetic member and a magnetic member, extends on the stator side and the other is provided on the mover side.