JPH09191633A - Linear servo coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cover the external circumference of a bar type magnet so that if a magnetic body is placed near the magnet by some reason, it is not attracted by the magnet not resulting in any deterioration of performance. SOLUTION: A linear servo coil is composed of a bar type magnet 1, a driving coil 3 loaded in coaxial to the external circumference of the bar type magnet 1, a control circuit for controlling power feeding to the driving coil 3 and a function body 8 provided at the external circumference or end portion of the driving coil 3. The bar type magnet 1 is formed of a manganese-aluminum magnet having the magnetization easy axis in its axial direction, the N pole and S pole are alternately formed in the axial direction of the external circumference, external circumference of the driving coil 3 is provided with a case 7 formed of a magnetic material covering the external circumference of the driving coil 3 and bar type magnet 1 and at least a part of the function body 8 is projected to outside of this case 7 from the aperture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear servo coil.

[0002]

2. Description of the Related Art In a conventional linear servo coil, a plurality of magnets are linearly arranged, a driving coil is arranged on the outer circumference of the magnet, and the energization of the coils is controlled by a control circuit. .

[0003]

The problem with the above-mentioned conventional example is that the energization of the coil is controlled.
Although this coil can be driven, if a magnetic substance such as a screw approaches the magnet arranged in a straight line for some reason, this magnetic substance is attracted to the magnet, and as a result, the magnet is linearly moved. The magnetic circuit formed by arranging in parallel with each other is disturbed and the performance is deteriorated.

Therefore, the present invention aims to prevent the performance deterioration of the linear servo coil.

[0005]

In order to achieve this object, the present invention provides a rod-shaped magnet, a driving coil concentrically attached to the outer periphery of the rod-shaped magnet, and energization of the driving coil. The rod-shaped magnet comprises a manganese-aluminum magnet having an easy magnetization direction in its axial direction, and a control circuit for performing control, and a functional body provided on an outer peripheral portion or an end portion of the drive coil. N poles and S poles are formed alternately in the axial direction of the outer peripheral surface, and a case made of a magnetic material that covers the outer periphery of the drive coil and the rod-shaped magnet is provided on the outer peripheral portion of the drive coil. At least a part of the functional body is projected out of the case through the opening.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention includes a rod-shaped magnet, a driving coil concentrically mounted on the outer periphery of the rod-shaped magnet, and an energization control for the driving coil. A control circuit to perform, and a functional body provided on an outer peripheral portion or an end portion of the drive coil, the rod-shaped magnet,
It consists of a manganese-aluminum magnet having an easy magnetization direction in its axial direction, and has an N pole and an S pole in the axial direction of its outer peripheral surface.
The poles are formed alternately, and on the outer peripheral portion of the drive coil,
A case made of a magnetic material that covers the outer periphery of the drive coil and the bar-shaped magnet is provided, and at least a part of the functional body is projected from the opening of the case to the outside of the case. By covering the outer periphery with the case, even if the magnetic body approaches for some reason, the magnetic body is not attracted to the magnet, and therefore the performance does not deteriorate. Further, since the case is made of a magnetic material, the case serves as a yoke, and the magnetic flux density crossing the coil is increased. As a result, the thrust force of the coil is increased.

[0007] The invention described in claim 2 of the present invention provides
The linear servo coil according to claim 1, wherein the case has a U-shaped cross section, support plates are attached to both ends of the case, and both ends of the bar-shaped magnets are supported by the support plates. Become a body.

[0008] The invention according to claim 3 of the present invention further provides
The linear servo coil according to claim 1 or 2, wherein a magnetic scale is provided outside the case, and the magnetic scale is not affected by the magnetic effect of the rod-shaped magnet, and the reliability of the magnetic scale is high. Become.

The invention according to claim 4 of the present invention is the linear servo coil according to claim 3 in which the magnetic scale is provided substantially parallel to the bar-shaped magnet, and the positional relationship between the magnetic scale and the bar-shaped magnet. You get the right one.

[0010] Further, the invention according to claim 5 of the present invention provides:
The magnetic flux density in the direction orthogonal to the axial direction of the N pole and the S pole on the outer peripheral surface of the bar magnet is displaced in a sine shape.
The linear servo coil described in any one of 1 to 4 can be configured as a single rod-shaped body without the need to linearly arrange a plurality of magnets as in the conventional case.

According to a sixth aspect of the present invention, the magnetic flux density in the direction perpendicular to the axial directions of the N pole and the S pole on the outer peripheral surface of the bar-shaped magnet is displaced into a square shape or a trapezoidal shape. The linear servo coil according to any one of claims 1 to 4, wherein a linear magnet can be obtained with a single rod-shaped body.

The invention according to claim 7 of the present invention is
The linear servo coil according to any one of claims 1 to 4, wherein the rod-shaped magnet has a substantially constant magnet density in the outer peripheral direction at a predetermined position, wherein the magnetic flux density is substantially constant in the peripheral direction. Therefore, the coil on the outer circumference of the coil can also obtain a uniform thrust in the circumferential direction, and the operation becomes smooth.

According to the eighth aspect of the present invention, the driving coil comprises a cylindrical bobbin and a lead wire wound around an outer peripheral portion of the bobbin. The length is the linear servo coil according to any one of claims 1 to 4, which is shorter than the axial length of one pole of the bar-shaped magnet, and a smooth operation is obtained as the linear servo coil. Become.

Further, the invention according to claim 9 of the present invention is
The linear servo coil according to claim 8 in which one unit of the coil is composed of a plurality of coils, and a smooth operation can be performed as the linear servo coil.

The invention according to claim 10 of the present invention is
The linear servo coil according to claim 9 in which the bobbin is provided with a collar for dividing the wire ring, wherein each wire ring can be accurately divided by the flange and the state after division can be stabilized.

Further, in the invention of claim 11 of the present invention, one unit of the coil is composed of three wire rings, and a current having a phase shift of 120 degrees is supplied from the control circuit to these three wire rings. According to the tenth aspect of the present invention, the smoothed thrust can be easily obtained by supplying a current having a phase shift of 120 degrees.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 is a bar-shaped magnet made of a manganese-aluminum alloy, and both ends thereof are supported by support plates 2 made of a magnetic material or synthetic resin.

The outer surface of the magnet 1 is mirror-finished, and a drive coil 3 is slidably mounted on the outer periphery of the magnet 1 as shown in FIGS.

The driving coil 3 is a cylindrical bobbin 4
And the lead wire 6 wound around the collar 5 on the outer circumference of the bobbin 4.
It is composed by.

Around the outer periphery of the drive coil 3 and the magnet 1, a case 7 made of a magnetic material having a U-shaped cross section is provided as shown in FIGS. 1 and 3, and the support is provided at both ends of the case 7. The plate 2 is fixed.

Further, functional bodies 8 are fixed to both ends of the bobbin 4 of the drive coil 3 as shown in FIG. As shown in FIGS. 2 and 1, the functional body 8 includes mounting plates 9 fixed to both ends of the bobbin 4 and a top plate 1 provided between the mounting plates 9.
0, and a component transfer arm 11 provided on the top plate 10.
And a sensor arm 12 that is integrated with the top plate 10 and that hangs down the outside of the case 7 from outside, and a part of the functional body 8 is provided by a mounting plate 9. Is drawn outward (upward) from the upper opening of the case 7.

On the other hand, below the sensor arm 12 and outside the case 7, a magnetic scale 13 is arranged substantially parallel to the magnet 1.

The arm 11 is provided with a rail 15 for carrying the component 14, and the component 14 held by the arm 11 is held and transported to the right side of the drawing in the example of FIG. .

Now, the magnet 1 of this embodiment is a rod-shaped one made of a manganese-aluminum alloy, and its easy magnetization direction is the axial direction.

Therefore, if the magnetized body 16 is provided outside the magnet 1 as shown in FIG. 4 and magnetized, as shown in FIG.
The poles and the S poles are alternately formed at predetermined intervals. That is, in FIG. 4, 17 is a bobbin, and this bobbin 1
A magnetizing coil 18 is wound around the outer periphery of 7 in consideration of the widths of the N pole and the S pole to be formed.
In, the direction of the flowing current is opposite. As a result, N-poles and S-poles are alternately formed on the magnet 1 in which the easy magnetization direction is the axial direction as described above, as shown in FIG.

FIG. 5 illustrates this point in more detail. As shown by the solid line in FIG. 5A, the magnetic flux density in the direction orthogonal to the axial direction of the N pole and the S pole on the outer peripheral surface of the magnet 1 is sine-shaped. It will be displaced to.

The broken line in (a) shows the case where the magnetic flux density is trapezoidal, but it may be square.

Then, (b) shows the state of the current to the magnetizing coil 18 and the magnetic field generated thereby.

In this state, paying attention to the bobbin 4, the lead wire 6 is wound between the collars 5 on the north pole and the south pole of the magnet 1 as shown in FIG. It is attached.

That is, in FIG. 2, units A to C constitute one coil unit, and units D to F constitute another unit coil, and the coils A to C and D to F of these respective units are constituted. A current having a phase shift of 120 degrees is supplied to the lead wire 6 by being controlled by the control circuit 19 shown in FIG.

By the way, the magnetic flux density on the outer periphery of the magnet 1 is displaced in a sine shape as shown in FIG. 5, and the coils A to C and DF of each unit shown in FIG. When a current flows through the lead wire 18 of the driving coil 3, a thrust acts on the driving coil 3, and this thrust is applied to the arm 11 which is a part of the functional body 8 when the component 14 is conveyed rightward by the arm 11 in FIG. The direction of the current flowing through the lead wire 18 is controlled so that it slides to the right. In addition, after the component 14 is transported, the lead wire 18 is used to move the arm 11 to the left.
The direction of the current flowing through is reversed.

The positional relationship between the driving coil 3 and the magnet 1 is determined by reading the magnetic scale 13 with the sensor 20 provided on the lower surface of the sensor arm 12 as shown in FIG. The electric current is transmitted to the control circuit 19 via the, and thereby the direction and strength of the current flowing through each lead wire 18 are controlled.

The case 7 shown in FIGS. 1 and 3 functions as a yoke outside the magnet 1 by providing the case 7, and by providing the case 7, the magnet 1
The magnetic flux density can be greatly increased from 2050 gauss on the surface to 2700 gauss, and 1150 gauss to 2250 gauss on 4 mm above the surface of the magnet 1. As a result, the thrust of the driving coil 3 is greatly increased. I was able to.

Further, by providing the case 7, the influence of the attractive force of the magnet 1 outside the case 7 can be drastically reduced, and as a result, the reliability of the magnetic scale 13 near the outside can be greatly improved. Further, even if a magnetic substance such as a screw approaches the outside of the case 7 for some reason, the magnetic substance is attracted to the magnet 1 and the performance is not deteriorated.

[0035]

As described above, the present invention includes a bar-shaped magnet,
A drive coil concentrically attached to the outer periphery of the rod magnet, a control circuit for controlling energization of the drive coil, and a functional body provided on the outer periphery or end of the drive coil. The rod-shaped magnet is made of a manganese-aluminum magnet having an easy magnetization direction in the axial direction, and N poles and S poles are alternately formed in the axial direction of the outer peripheral surface thereof, and the outer peripheral portion of the drive coil is formed. Is provided with a case made of a magnetic material that covers the outer circumference of the drive coil and the rod-shaped magnet, and at least a part of the functional body is projected from the opening of the case to the outside of the case. By covering the outer circumference of the magnet with a case, even if the magnetic body approaches for some reason, it will not be attracted to the magnet,
Therefore, no performance deterioration occurs. Further, since the case is made of a magnetic material, the case serves as a yoke, and the magnetic flux density crossing the coil is increased. As a result, the thrust force of the coil is increased.

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment of the present invention.

FIG. 2 is a vertical sectional view taken along line II-II in FIG.

FIG. 3 is a vertical sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view showing the magnetized state.

FIG. 5 is a diagram showing the magnetic flux density of the magnet.

FIG. 6 is a block diagram showing its control circuit.

[Explanation of symbols]

 1 Magnet 2 Support Plate 3 Driving Coil 7 Case 8 Functional Body 13 Magnetic Scale

Claims (11)

[Claims] 1. A rod-shaped magnet, a drive coil concentrically mounted on the outer periphery of the rod-shaped magnet, a control circuit for controlling energization of the drive coil, and an outer peripheral portion or an end of the drive coil. The rod-shaped magnet is made of a manganese-aluminum magnet having an easy magnetization direction in its axial direction, and an N pole and an S pole are alternately arranged in the axial direction of its outer peripheral surface. A case made of a magnetic material is formed on the outer peripheral portion of the drive coil to cover the outer periphery of the drive coil and the rod-shaped magnet, and at least a part of the functional body is provided through the opening of the case. Linear servo coil protruding outside. 2. The linear servo coil according to claim 1, wherein the case has a U-shaped cross section, and support plates are attached to both ends of the case, and both ends of the bar-shaped magnet are supported by the support plates. 3. The linear servo coil according to claim 1, wherein a magnetic scale is provided outside the case. 4. The linear servo coil according to claim 3, wherein the magnetic scale is provided substantially parallel to the rod-shaped magnet. 5. The linear magnet according to claim 1, wherein the magnetic flux density in the direction orthogonal to the axial direction of the N pole and the S pole on the outer peripheral surface of the bar-shaped magnet is displaced in a sine shape. Servo coil. 6. The magnetic flux density in the direction orthogonal to the axial direction of the N pole and the S pole on the outer peripheral surface of the bar-shaped magnet is displaced in a rectangular shape or a trapezoidal shape. Linear servo coil described in. 7. The linear servo coil according to claim 1, wherein the rod-shaped magnet has a substantially constant magnet density in the outer peripheral direction at a predetermined position thereof. 8. The drive coil comprises a cylindrical bobbin and a lead wire wound around the outer periphery of the bobbin, and the axial length of one unit of the coil is the axial direction of one pole of the bar magnet. The linear servo coil according to claim 1, wherein the linear servo coil is shorter than its length. 9. The linear servo coil according to claim 8, wherein one unit of the coil is a plurality of coils. 10. The linear servo coil according to claim 9, wherein the bobbin is provided with a collar that divides the wire ring. 11. The linear servo coil according to claim 10, wherein one unit of the coil comprises three coils, and a current having a phase shift of 120 degrees is supplied from the control circuit to these three coils.