JPH0721103Y2 - Linear induction motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a linear induction motor, and more particularly to a linear induction motor having a core and a conductor on a secondary side.

[Prior Art] FIG. 2 is a diagram showing a conventional example of a linear induction motor,
The linear induction motor has a drive shaft 2 penetrating through a casing 1 so as to be reciprocally movable in the axial direction, and a cylindrical primary side core 3 surrounding the drive shaft 2 and an inner peripheral portion of the drive shaft 2 on an inner wall portion of the casing 1. An embedded primary coil 4 is provided, and a secondary shaft 5 having a cylindrical shape and a secondary conductor 6 such as aluminum integrated so as to cover the outer periphery thereof are attached to the drive shaft 2. Then, the moving magnetic field generated from the primary coil 4 linearly moves the drive shaft 2 and switches the direction of the moving magnetic field to perform a reciprocating linear motion.

[Problems to be Solved by the Invention] However, since the secondary side core 5 increases the inertial mass of the movable portion, the response characteristics at the time of start-up, stop and reciprocating motion are poor, and the primary side coil 4 has There is a problem that a large amount of exciting current is required, and the power consumption increases when the reciprocating motion and the number of times of starting are large.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a linear induction motor in which a movable part is lightened to improve response characteristics.

[Means for Solving the Problems] In the linear induction motor according to the present invention, a casing, a drive shaft that is axially reciprocated inside the casing, and a drive shaft that moves in the moving direction of the drive shaft. A primary coil that generates a magnetic field and is integrally disposed inside the casing, and a secondary coil that is integrally disposed inside the casing through a gap inside the primary coil and that has a hole that penetrates the drive shaft. A configuration including a side core and a secondary side conductor arranged in a gap between the primary side coil and the secondary side core and connected to the drive shaft is adopted.

[Operation] According to the linear induction motor of the present invention, the secondary side core and the secondary side conductor are separated, and only the secondary side core and the drive shaft are reciprocally moved in the axial direction inside the casing. The weight of these movable parts is reduced.

[Embodiment] An embodiment of the linear induction motor according to the present invention will be described with reference to FIG.

Also in this embodiment, the drive shaft 2 is penetrated through the casing 1 so as to be reciprocally movable in the axial direction, and the inner wall portion of the casing 1 is provided with the cylindrical primary core 3 surrounding the drive shaft 2 and the inner peripheral portion thereof. The embedded primary coil 4 is provided, but the secondary core 5 and the secondary conductor 6 are separated, and the secondary core 5 is separated from the drive shaft 2 in a fixed state together with the primary coil 3. The points are different.

That is, the secondary core 5 has the drive shaft 2 at the center thereof.
A hole 5a larger than the outer diameter of the drive shaft 2 is passed through the hole 5a in a non-contact state, and one end of the drive shaft 2 is fixed to the inner wall of the casing 1 through the support member 7, and the outer peripheral surface of the casing 1 is fixed. There is a gap G between the inner peripheral surface of the primary core 3 and the inner core.

The secondary-side conductor 6 is formed in a cylindrical shape with one end closed, and the drive shaft 2 is connected to one end of the secondary-side conductor 6 in a penetrating state, and the cylindrical part 6a is connected to the primary core 3 and the secondary side. It is arranged in a gap G between the core 5 and the cores 5 so as to be concentric with the cores 3 and 5.

The linear induction motor having such a configuration is configured such that the primary coil 4
When a moving magnetic field is generated by sequentially applying an exciting current to the magnetic core, a magnetic circuit is formed between the primary core 3 and the secondary core 5, and a secondary circuit in the gap G between the cores 3 and 5 is formed. An axial thrust force is generated in the cylindrical portion 6a of the side conductor 6 according to the moving magnetic field, so that the drive shaft 2 can be linearly moved, and the direction of the moving magnetic field can be changed by switching the exciting current of the primary side coil 4. Instead, a linear reciprocating motion can be performed.

In this case, the secondary core 5 and the secondary conductor 6 are separated,
Since only the secondary-side conductor 6 is connected to the drive shaft 2 and the movable portion is light, the inertial force at the time of turning back and forth of the reciprocating motion and at the time of starting and stopping is reduced, and the response characteristic is improved.
Power consumption can be reduced. Therefore, it can be used for, for example, a linear oscillator of a linear compressor that requires high-speed reciprocating motion. Further, since the movable portion is light, the force applied to the bearing of the drive shaft is reduced, and the durability is improved.

Although the secondary-side conductor 6 is composed only of a non-magnetic material such as aluminum in the above-mentioned embodiment, if the resistance of the secondary-side conductor needs to be increased due to the characteristics of the motor, the surface of the magnetic material may be changed. Alternatively, a non-magnetic material such as aluminum may be formed into a thin plate shape and bonded together.

[Effects of the Invention] As described above, according to the linear induction motor of the present invention, the secondary side core and the secondary side conductor are separated, and the secondary side core is fixed together with the primary side coil so that the drive shaft does not move. Since it is separated, the movable part becomes lighter, the inertial force at the time of turning back and forth of the reciprocating motion and at the time of starting and stopping is improved, the response characteristic is improved, and the power consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the linear induction motor of the present invention, and FIG. 2 is a vertical sectional view showing a conventional linear induction motor. 1 ... Casing, 2 ... Drive shaft, 3 ... Primary core,
4 ... Primary side coil, 5 ... Secondary side core, 6 ... Secondary side conductor, 7 ... Support member.

Claims (1)

[Scope of utility model registration request] 1. A casing (1), a drive shaft (2) reciprocally moved in the axial direction inside the casing, and a moving magnetic field along the moving direction of the drive shaft to integrally form inside the casing. A secondary side having a primary side coil (4) arranged therein and a hole (5a) integrally formed inside the casing through a gap (G) inside the primary side coil and penetrating a drive shaft. A linear induction motor comprising: a core (5); and a secondary side conductor (6) arranged in a gap between the primary side coil and the secondary side core and connected to the drive shaft.