JP3291045B2 - Linear motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving magnet type linear motor, and more particularly to an actuator for a vibration canceller, an electronic sewing machine, a displacement meter, a pen drive source of a measuring instrument, and a sorter for sorting using vibration. The present invention relates to a linear motor suitable for a driving source of a vehicle.

[0002]

2. Description of the Related Art A moving coil type linear motor is disclosed in Japanese Utility Model Publication No. 1-171578.

FIG. 4 is a block diagram of a linear motor described in Japanese Utility Model Publication No. 1-171578. In the drawing, reference numeral 1 denotes a hollow cylindrical side yoke, and reference numeral 2 denotes a hollow cylindrical center yoke in which an outer cylindrical surface is disposed at a constant interval with respect to an inner wall surface of the side yoke.

[0004] On the inner wall surface of the side yoke 1, first and second coils 3, 4 are provided at predetermined intervals. A first coil 3 is provided on the outer cylinder surface of the center yoke.
And a fourth coil 6 opposed to the second coil 4 are provided.

[0005] Reference numeral 7 denotes a nonmagnetic movable element supported in a space between the inner cylindrical surface of the side yoke 1 and the outer cylindrical surface of the center yoke 2 so as to be movable in the axial direction. A cylindrical portion of the mover 8 between the first coil 3 and the third coil 5 has a first magnet 9 substantially constituting the cylindrical surface of the mover 8.
Mover 8 between the second coil 4 and the fourth coil 6
Substantially constitute the cylindrical surface of the mover 8,
Second magnets 10 whose magnetization directions are opposite to the first magnets 9 are provided.

Then, as shown by a broken line in the figure,
First coil 3 → first magnet 9 → third coil 5
→ A center yoke 2 → a fourth coil 6 → a second magnet 10 → a second coil 4 → a magnetic circuit having a magnetic flux flowing through the side yoke 1 is formed.

Next, the operation of the above configuration will be described. When an electric current is applied to the first coil 3, the second coil 4, the third coil 5, and the fourth coil 6 so as to have magnetic polarities as shown in the drawing, the first to fourth coils 3 to 6 The mover 8 moves in the direction of the arrow A due to the reaction of the thrust generated in the above.

[0008]

However, in the linear motor having the above structure , the first coil 3 and the second coil
4, do not supply current to the third coil 5 and the fourth coil 6.
In this case, there is a problem that the mover 8 moves freely.
You.

[0009]

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to stop the mover at a fixed position when power is not supplied.
It is to provide a linear motor that stops.

[0012]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising:
And a housing made of a hollow cylindrical magnetic body having a first groove and a second groove formed therein , and disposed on a central axis of the housing so as to be movable in the axial direction within the housing. A spindle supported on both end faces, a cylindrical yoke fixed to the spindle, and having an outer cylinder face opposed to the inner cylinder face of the housing via a space, and a radius mounted on the outer cylinder face of the yoke; A first magnet magnetized in a direction, and mounted on the outer cylinder surface of the yoke so as to be adjacent to each other with an interval in the axial direction of the yoke and the first magnet; A second magnet having a reverse magnetization direction and the first magnet on the inner cylindrical surface of the housing;
A first coil provided in the opposing portion of the magnet on the inner cylindrical surface of said housing, and a second coil provided in the opposing portion of the second magnet, made from the Howe
In the axial direction of the jing, the second magnet of the first magnet
From the surface opposite to the surface facing the magnet,
The opposite side of the face of the gnet facing the first magnet
Distance between the first groove and the second groove of the housing.
Characterized in that it is longer than the distance between the groove
It is a linear motor.

[0013]

[0014]

[0015]

In the linear motor according to the first aspect of the present invention,
A magnetic circuit is formed between the housing, the first magnet, the yoke, the second magnet, and the housing, and when a current is applied to the first coil and the second coil disposed in the magnetic gap of the magnetic circuit, As a reaction of the force acting on the coil, a thrust is generated in the yoke, and the yoke and the yoke are fixed, and the spindle, which is arranged to be movable in the axial direction in the housing, moves on the center axis of the housing.

[0016]

[0017]

[0018]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a right side view in FIG. 1, and FIG. 3 is an enlarged configuration view near a bobbin in FIG.

First, in FIGS. 1 and 2, reference numeral 20 denotes a hollow cylindrical housing whose both end faces are open and made of a magnetic material. A front cover 21 is provided on one open end surface of the housing 20, and a rear cover 22 is provided on the other open end surface thereof with screws 23, 23, respectively.
24. Furthermore, housing 2
0, the first groove 20 is formed in the circumferential direction at intervals in the inner cylindrical surface.
a, a second groove 20b is formed.

Holes 21a and 22a are formed in the center portions of the front cover 21 and the rear cover 22, respectively. A spindle 27 is provided in these holes 21a and 22a via bearings 25 and 26 in the axial direction of the housing 20. It is arranged movably.

Reference numeral 28 denotes a cylindrical yoke which is fixed to the spindle 27 and whose outer cylindrical surface faces the inner cylindrical surface of the housing 20 via a space. A first magnet 29 magnetized in the radial direction (the inner cylinder surface side of the housing 20 has an S pole) on the outer cylinder surface of the yoke 28, and the first magnet 29.
The second magnet 30 is attached to the yoke 28 so as to be adjacent to the first magnet 29 at an interval in the axial direction, and has a magnetization direction opposite to that of the first magnet 29 (the inner cylinder surface side of the housing 20 is the N pole).
Are provided.

Reference numeral 35 denotes a housing made of a non-magnetic material.
Is a hollow cylindrical bobbin disposed in the vicinity of the inner cylinder surface.
On the cylindrical surface of the bobbin 35 facing the inner cylindrical surface of the housing 20, a first coil 31 provided on a facing portion of the first magnet 29 and a facing portion of the second magnet 30 are provided. A second coil 32 is provided.

Therefore, as shown in FIG.
0 → the first coil 31 → the first magnet 29 → the yoke 28 → the second magnet 30 → the magnetic circuit having a magnetic flux flowing through the second coil 32 is formed.

Next, the bobbin 35 will be described in more detail with reference to FIG. A first concave portion 36 around which the first coil 31 is wound and a second concave portion 37 around which the second coil 32 is wound, on a cylindrical surface of the bobbin 35 facing the inner cylindrical surface of the housing 20. And a first concave portion 36 formed on the cylindrical surface of the first concave portion 36 opposite to the second concave portion 37, and
A first small groove 39 in which a lead wire 38 for supplying a current to the coil 31 is disposed, and a first concave portion 36 of the second concave portion 37
And a second small groove 41 on which a lead wire 40 for supplying a current from the outside of the yoke 28 to the second coil 32 is provided.

The space between the first coil 31, the second coil 32 and the inner cylindrical surface of the housing 20 is filled with a substance having high thermal conductivity. In this embodiment, the magnetic fluid 42 is filled. Furthermore, the axial direction of the housing 20
The pair of the first magnet 29 and the second magnet 30
From the surface 29a opposite to the surface facing the second magnet 30
Surface 30 opposite to the surface facing first magnet 29
a to the first groove 20 of the housing 20.
a and the distance (A) between the second groove 20b and the second groove 20b.
I made it.

Next, the operation of the above configuration will be described. When an electric current is applied to the first coil 31 and the second coil 32 using the lead wires 38 and 40, the electric current is generated in the first coil 31 and the second coil 32 provided in the magnetic gap of the magnetic circuit. By the reaction of the thrust, the yoke 28 and the spindle 27 move in the direction of the arrow in FIG.

According to the above configuration, the magnetic gap of the magnetic circuit is located at one location between the coils 31 and 32 and the magnets 29 and 30, and the distance of the magnetic gap is shorter than that of the conventional example having two locations. Since the first and second magnets are directly attached to the yoke 28 by the magnetic attraction of the magnets themselves, the magnetic resistance is much smaller.

The spindle 27, which is a mover, is supported at both ends by bearings 25, 26 provided on covers 21, 22 on both end surfaces of the housing 20, so that the stroke of the spindle 27 can be lengthened. .

The first coil 31 and the second coil 3
2 is a bobbin 3 on the inner cylindrical surface of the housing 20 which is a fixed side.
5, the lead wires 38, 40
Can be easily pulled out.

Further, each of the coil and the magnet is 2
In short, since the magnets 29 and 30 are attached to the yoke 28 by their own magnetic attraction, the structure is simple and the cost is low.

The first magnet 29 and the second magnet 30 are arranged near the bearings 25 and 26, respectively, so that magnetic vibration is hardly generated. Since the heat generated in the first coil 31 and the second coil 32 is transmitted to the housing 20 via the magnetic fluid 42 in a smooth manner, the heat radiation is improved.

The first coil 31 and the second coil 32
Filling the space between the inner cylinder surface of the housing 20 with magnetic fluid
By reducing the magnetic flux loss of the magnetic circuit
Can be.  With a space between the inner cylindrical surface of the housing 20
The first groove 20a and the second groove 20b are formed along the circumferential direction.
As a result, the first coil 31 and the second coil 3
2, when the current is not long, the first magnet 29,
The second magnet 30 moves to a position where the magnetic resistance is low.
That is, the first groove 20a and the second groove
Move so as to face the surface formed between the groove 20b
Further, in the axial direction of the housing 20, the first magnetic
Of the unit 29 opposite to the surface facing the second magnet 30
From the surface 29a of the first magnet of the second magnet 30.
Distance to the surface 30a opposite to the surface facing the
(B) shows the first groove 20 a and the second groove of the housing 20.
20b or more (A)
Thus, the first magnet 29, the second magnet 30,
The mover including the yoke 28 and the spindle 27 is a magnetic
Fixed at the center of the road.

The present invention is not limited to the above embodiment. For example, the substance filling the space between the first coil 31, the second coil 32 and the inner cylindrical surface of the housing 20,
The material is not limited to magnetic fluids, but may be a mixture of resin or adhesive mixed with a magnetic substance (powder), or a material with high thermal conductivity
A resin or an adhesive containing (for example, aluminum powder), a resin or an adhesive having a high thermal conductivity may be used.

[0034]

As described above, according to the present invention, there is no communication.
It is possible to realize a linear motor in which the mover does not move when power is applied.

[Brief description of the drawings]

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

FIG. 2 is a right side view in FIG.

FIG. 3 is an enlarged configuration diagram near a bobbin in FIG. 1;

FIG. 4 is a configuration diagram of a linear motor described in Japanese Utility Model Publication No. 1-171578.

[Explanation of symbols]

 Reference Signs List 20 housing 27 spindle 28 yoke 29 first magnet 30 second magnet 31 first coil 32 second coil 35 bobbin 42 magnetic fluid

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-28606 (JP, A) JP-A-59-32353 (JP, A) Fully open 1979-95818 (JP, U) Really open 1984 3780 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H02K 33/16

Claims (1)

(57) [Claims] (1) Along the circumferential direction with an interval on the inner cylindrical surface.
A hollow cylindrical magnetic material housing (20) having a first groove (20a) and a second groove (20b) formed therein ; and a housing (20) on a central axis of the housing (20). 20) a spindle (27) movably arranged in the axial direction in the inside and supported on both end faces of the housing (20);
A cylindrical yoke (28) fixed to the spindle (27) and having an outer cylindrical surface opposed to the inner cylindrical surface of the housing (20) via a space, and on an outer cylindrical surface of the yoke (28). A first magnet (29) radially magnetized and mounted on the outer cylindrical surface of the yoke (28) in an axial direction of the first magnet (29) and the yoke (28). A second magnet (30) mounted so as to be adjacent to and spaced from the first magnet (29) and having a magnetization direction opposite to that of the first magnet (29);
And a first coil (3) provided on the inner cylindrical surface of the housing (20) at a portion facing the first magnet (29).
1) and a second coil (3) provided on the inner cylindrical surface of the housing (20) at a portion facing the second magnet (30).
And 2), it consists, in the axial direction of the housing (20), said first magnetic
The second magnet (30) of the slot (29).
From the surface (29a) opposite to the surface
(30) A surface facing the first magnet (29)
Distance (B) to the surface (30a) opposite to the
The first groove (20a) and the second groove (20) of the jing (20).
(b) or more .