JPH05161339A - Permanent magnet type linear motor - Google Patents

Abstract

PURPOSE:To shorten the length of a mover, and lighten it, and besides, to avoid torque shortage and the drop of reliability in drive control. CONSTITUTION:Position detecting elements 30a, 30b, and 30c are arranged at the position within the range of movement of a mover 26, besides being the side of one end of a stator, and position detecting elements 30d, 30e, and 30f are arranged at the positions within the range of movement of the mover 26 also on the side of the other end of the stator 21. The length of the mover 26 is set to such a length that each end of this mover 26 opposes the stator at about half area of the stator 21, respectively, at both ends positions within the movement range. Moreover, the length in the direction orthogonal to the direction of movement of the permanent magnet 28a opposed to the stator 21 at each end of this mover 26 is set to be about double the length of the permanent magnet 28b positioned at the other position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet type linear motor having a stator having a stator core and a stator coil, and a rotor having a permanent magnet.

[0002]

2. Description of the Related Art FIGS. 7 to 12 show an example of a conventional permanent magnet type linear motor. 7 and 8, the stator 1 is configured to have a stator core 2 and a stator winding 3. The stator core 2 is made of a laminated core, and is fixed to the case 5 with both side portions clamped by the side plates 4. As shown in FIG.
The stator core 2 is provided with the three-phase stator windings 3 at a predetermined pole pitch τ.

A mover 6 is arranged in the case 5 via a wheel 6a so as to face the stator 1 with a gap g, and the mover 6 is in the direction of arrow A (see FIG. 7) and arrow. It is provided so as to be capable of reciprocating in the B direction (see FIG. 9). The mover 6 is configured by mounting a plurality of permanent magnets 8 on a base 7, and the arrangement pitch of the permanent magnets 8 is
As shown in FIG. 11, it is the same as the pole pitch τ, and the width dimension along the moving direction is set to (2/3) τ. The moving body 6 is provided with a moving body 9.

Further, position detecting elements 10a, 10b and 10c are mounted on the mounting plate 1 in the direction of one end of the stator 1.
It is arranged so as to face each of the permanent magnets 8 through 1. Of the position detecting elements 10a, 10b, 10c, the position detecting element 10a located closer to the stator 1 is located at a distance of Na × τ from the magnetic pole center P of the stator 1 (Na is a positive value). Integer), the remaining position detection element 10b,
10c are each at a distance of (2/3) τ intervals.

The detection signals of the position detecting elements 10a, 10b, 10c are given to a control circuit 12 as shown in FIG. 12, and the control circuit 12 drives the driving element 12 based on the respective detection signals.
By controlling a, the switching of the electric current to and from the stator winding 3 is controlled. As a result, the mover 6 receives the propulsive force from the stator 1 and is controlled to reciprocate within the range of the stroke x. The positions of both ends of each moving range are shown in FIGS. 7 and 9, respectively.

Here, as shown in FIG.
The length I is approximately the length K of the stator 1 and the distance S from the end of the stator 1 to the farthest position detecting element 10c,
It is set based on the total length of the stroke x.

[0007]

However, in the above-described conventional structure, the length of the moving element 6 is long, which causes a problem that the size of the linear motor itself becomes long for its moving stroke. Further, since the length of the moving element 6 is long, the weight of the moving element 6 is heavy, and a large propulsive force for the moving element 6 is required. In order to deal with this, it is necessary to increase the output torque of the stator 2, and as a countermeasure against this, increase the lamination thickness of the stator core 2 or increase the current flowing through the stator winding 3. To be done. However, in this case, the entire linear motor becomes heavier, the power consumption increases, and the drive element 12 made of the switching semiconductor of the control circuit 12 is used.
There arises a problem that the rated capacity of a must be increased.

The present invention has been made in consideration of the above circumstances. Therefore, the object of the present invention is to shorten the length of the moving element, without causing torque shortage and deterioration of drive control reliability. It is to provide a permanent magnet type linear motor.

[0009]

A permanent magnet type linear motor of the present invention includes a stator having a stator core and a stator coil, and a mover having a permanent magnet and reciprocating by receiving thrust from the stator. , A position detecting element for detecting the position of the mover, wherein the ends of the mover move so as to face each other in substantially half the area of the stator at both end positions of the moving range of the mover. The length of the child is set, and the length in the direction orthogonal to the moving direction of the permanent magnet facing the stator at each end position of the mover is set to be substantially the same as the length of the permanent magnets located in other parts. It is characterized in that it is set to be doubled, and the position detecting elements are arranged on both sides of the stator so as to be positioned within the moving range of the moving element.

[0010]

According to the above means, the length of the mover is set so that the ends of the mover face each other in substantially half the area of the stator at both ends of the moving range of the mover. The length of the mover can be shortened.

In this case, the moving element faces only the half of the area of the moving element at both ends of its moving range, so there is a risk that the starting torque or the braking torque will be insufficient. However, according to the means of the present invention, the length in the direction orthogonal to the moving direction of the permanent magnet facing the stator at each end position of the moving range of the moving element is the same as the length of the permanent magnet located in another portion. Since it is set to be approximately twice the height, it is possible to supplement the magnetomotive force, which tends to be insufficient, so that there is no fear of insufficient starting torque or braking torque.

Further, since the position detecting elements are arranged on both sides of the stator so as to be positioned within the moving range of the moving element, the position of the moving element can be reduced while reducing the length of the moving element. It is possible to always detect, and it is possible to always perform good drive control of the moving element.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2,
The stator 21 includes a stator core 22 and a stator winding 23. The stator core 22 is a laminated core, and is fixed to the case 25 in a state where both side portions are clamped by the side plates 24. As shown in FIG. 3, the stator core 22 is provided with three-phase stator windings 23 at a predetermined pole pitch τ.

In the case 25, a mover 26 is arranged via wheels 26a so as to face the stator 21 with a gap g, and the mover 26 is arranged in the direction of arrow A in FIG. 1 and in FIG. It is provided so as to be able to reciprocate in the direction of arrow B. The mover 26 includes a base 27 having a plurality of permanent magnets 2
8a and 28b are attached, the arrangement pitch of the permanent magnets 28a and 28b is the same as the pole pitch τ as shown in FIG. 4, and the width dimension along the moving direction is (2 / 3) is set to τ. The moving body 26 is provided with a moving body 29.

Further, position detecting elements 30a, 30b and 30c are attached to the mounting plate 31 at one end side (the left side in the figure) of the stator 21 and within the movement range of the mover 26.
It is arranged so as to face each of the permanent magnets 28a and 28b through. Each position detecting element 30a, 30b, 3
0c, the position detecting element 30a located closer to the stator 21 is located between the magnetic pole center P1 of the stator 1 and Nb.
The remaining position detecting elements 10b and 10c located at a distance of × τ (Nb is a positive integer) are at a distance of (2/3) τ.

Further, as shown in FIG. 6, the stator 21
Position detecting elements 30d, 30e, 30f are also arranged on the other end side of the moving element 26 within the movement range of the moving element 26 so as to face the permanent magnets 28a, 28b through the mounting plate 32. Each position detection element 30d, 30e, 30
The position detection element 30d, which is located farthest from the stator 21 of f, is located between the magnetic pole centers P2 to N of the stator 1.
The remaining position detecting elements 30e and 30f located at a distance of b × τ (Nc is a positive integer) are at a distance of (2/3) τ.

Here, the length Ii of the mover 26 is set as follows. That is, FIG. 1 showing the position on the one end side of the moving range (the stroke is shown by reference numeral xa in FIGS. 1 and 6) of the moving element 26, and the position on the other end side of the moving range. As shown in FIG. 6, the length Ii of the moving element 26 is such that each end of the moving element 26 has a substantially half region Ka (FIG. 1) of the stator 21.
The length is set so as to face Kb (FIG. 6).

Further, of the permanent magnets 28 of the stator 21, the permanent magnets facing the above-mentioned areas Ka and Kb (this is designated by reference numeral 28).
As shown in FIG. 4, the length Ma in the direction orthogonal to the moving direction is substantially the same as the length Mb of the permanent magnet (which is indicated by reference numeral 28b) located in another portion. Two
It is set to double.

The position detecting elements 30a, 30b, 30c,
As shown in FIG. 5, the detection signals of 30d, 30e, and 30f are given to the control circuit 33, and the control circuit 33 controls the drive element 33a based on each detection signal to control the stator winding 23.
The on / off control is performed. As a result, the mover 26 receives the propulsive force from the stator 21 and is controlled to reciprocate within the stroke xa.

According to this embodiment, the moving member 26
Since the length Ii of the moving element 26 is set so that the end portions of the moving element 26 face each other in substantially half regions Ka and Kb of the stator 21 at both ends of the moving range of
As is clear from the comparison with the related art shown in FIGS. 7 and 8, the length Ii of the mover 26 can be shortened. As a result,
The weight can be reduced.

In this case, the mover 26 has approximately half the areas Ka, K of the stator 21 at both ends of its moving range.
Since they face each other only at b, there is a concern that the starting torque or the braking torque will be insufficient. However, according to this embodiment,
At each end position of the moving range of the moving element 26, the stator 21
The length Ma in the direction orthogonal to the moving direction of the permanent magnet 28a opposed to is set to be approximately twice the length Mb of the permanent magnet 28b located at another portion, and therefore tends to be insufficient. The magnetomotive force can be supplemented, and therefore there is no fear that the starting torque or the braking torque will become insufficient.

The position detecting elements 30a, 30b,
Since 30c, 30d, 30e, and 30f are arranged so as to be located on both sides of the stator 21 and within the moving range of the mover 26, the length of the mover 26 can be shortened and the mover 26 The position can be detected at all times, and the mover 2
The drive control of 6 can always be performed well.

[0023]

As is apparent from the above description, the permanent magnet type linear motor of the present invention can shorten the length of the moving element and can reduce the size of the entire moving element, and does not increase the power consumption and the torque is insufficient. It is possible to eliminate the above-mentioned problem, and there is an excellent effect that the reliability of drive control is not deteriorated.

[Brief description of drawings]

FIG. 1 is an overall vertical side view showing an embodiment of the present invention.

[Fig. 2] Front view in vertical section

FIG. 3 is a cutaway side view of a stator portion.

FIG. 4 is a perspective view showing a permanent magnet portion of a moving element.

FIG. 5 is a block diagram showing an electrical configuration.

FIG. 6 is a diagram corresponding to FIG. 1 for explaining the operation.

FIG. 7 is a view corresponding to FIG. 1 showing a conventional example.

FIG. 8 is a view corresponding to FIG.

FIG. 9 is a view corresponding to FIG.

FIG. 10 is a view corresponding to FIG.

FIG. 11 is a view corresponding to FIG.

FIG. 12 is a view corresponding to FIG.

[Explanation of symbols]

21 is a stator, 22 is a stator core, 23 is a stator winding,
26 is a mover, 28a and 28b are permanent magnets, 30a and 3
Reference numerals 0b, 30c, 30d, 30e and 30f denote position detection elements, and 33 denotes a control circuit.

Claims (1)

[Claims] 1. A stator having a stator core and a stator coil, a mover having a permanent magnet that reciprocates by receiving thrust from the stator, and a position detection element that detects the position of the mover. In addition, the length of the mover is set so that the ends of the mover face each other in substantially half regions of the stator at both end positions of the moving range of the mover. The length in the direction orthogonal to the moving direction of the permanent magnet facing the stator at each end position is set to be approximately twice the length of the permanent magnet located in another portion, and the position detection is performed. A permanent magnet type linear motor, wherein elements are arranged on both sides of the stator so as to be located within a moving range of the mover.