JP3217476B2 - Cylindrical 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 drive shaft for an industrial robot, a machine tool, and the like, and more particularly, to a drive motor that requires linear drive as well as rotary drive.

[0002]

2. Description of the Related Art In dedicated machines such as machine tools and shearing machines, linear motors of various structures have been conventionally used. For example, as a flat plate type linear motor, there is a permanent magnet type linear synchronous motor as shown in FIG.

The permanent magnet type linear synchronous motor 101
The permanent magnets 5 are disposed on the upper surface of the secondary frame 103 so that the N and S poles are alternately arranged. The primary-side magnetic pole pieces 107 a and 107 b are fixed to the primary-side frame 109 while maintaining a predetermined interval X on the permanent magnet 105.

The primary windings 107a and 107b are U,
V and W three-phase windings 111 are provided, and the distance between the primary pole pieces 107a and 107b is fixed to the primary frame 109 with a predetermined phase. The primary side frame 109 is connected to a machine side (not shown).

[0005] In the displacement shown in FIG.
The W-phase winding 111 of the primary-side magnetic pole pieces 107a and 107b is disposed above the S pole.

[0006] The flat plate type linear motor has the above-described configuration, and cannot be used for a drive device that requires simultaneous rotation and linear motion.

FIG. 12 shows a cylindrical linear motor.
There is a linear induction motor as shown in FIG. In this cylindrical linear motor, a primary iron core 123 is disposed around a rod 121 made of a rod-shaped conductor, and an appropriate slot 1 is provided in the iron core.
25, and a primary coil 127 is provided in the slot.

Since the primary iron core 123 of such a cylindrical linear motor is usually formed integrally, there is a problem that the flow direction of the magnetic force lines generated by the primary coil becomes uneven or the leakage of the magnetic force lines is large. Occurs.

[0009]

As described above,
Conventionally used cylindrical linear motors have a problem that the leakage of magnetic lines of force is large, the temperature rises due to heat generation, and the efficiency is poor.

The present invention has been made to solve such a problem.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a movable element in which a ring-shaped permanent magnet radially magnetized is attached to a movable shaft, and a circular hole inside the movable element which is larger than the outer shape of the permanent magnet. A plurality of first core portions each having a plate-shaped magnetic body having a polygonal outer surface laminated in the stroke direction of the mover; and a plate-shaped magnetic body formed around the outer periphery of the first core portion by the mover. An armature core comprising a second core portion laminated in a circumferential direction; an armature coil wound in a ring shape inserted in a slot provided between the first core portion and the first core portion; The power supply for supplying a current to the armature coil was provided.

[0012]

The magnetic line of magnetic field generated by the armature coil is a magnetic circuit composed of a plate-like magnetic material along the flow direction, that is, a first magnetic circuit composed of a plate-like magnetic material laminated in the stroke direction of the movable shaft. It flows through a magnetic circuit composed of a core portion and a second core portion made of a plate-shaped magnetic material laminated in the circumferential direction of the movable shaft. Therefore, magnetic leakage is small.
This magnetic field also acts uniformly on the movable shaft provided with the radially magnetized permanent magnets provided therein in the circumferential direction. Therefore, the movable shaft receives only the thrust in the stroke direction, and does not exert a suction force in the rotation direction in the vertical and horizontal directions.

[0013]

1 shows a first embodiment in which the present invention is applied to a drill. In FIG. 6, the drill 1 is mounted on a drill chuck 3, which is driven in the axial direction by a linear motor 5 and is driven to rotate by a rotary motor 7.
The linear motor 5 and the rotary motor 7 are connected by connecting means 6. The connecting means 6 is constituted by a means capable of rotating motion on a shaft which moves linearly, for example, a means provided with a spline shaft. Since the rotating motor 7 is based on a known technique, description thereof will be omitted below. In addition to the above, the present invention can be used as a drive motor that is attached to a robot arm and tightens nuts and bolts, and is provided on a dedicated machine tool and is used as a drive motor for tapping work. Hereinafter, the linear motor 5 will be described together with the present invention.

FIG. 1 is a sectional view schematically showing the overall structure of a first embodiment of the present invention. In FIG. 1, a mover 11 is a ring-shaped magnet 13a, 1 having different magnetic poles as shown in FIG.
3b is arranged on the movable shaft 13 alternately. The magnets 13a and 13b are permanent magnets that are radially magnetized so that the outside has north poles or south poles, and may be made of phyllite or any magnet steel.

The armature core 21 is configured as follows. That is, the magnet 13 is provided inside as shown in FIG.
A plate-shaped magnetic body 27 having a circular hole 23 through which a and 13b can pass and having a polygonal shape on the outside, for example, a regular octagon 25, is laminated in the axial direction of the movable shaft as shown in FIG. One core portion 29 is formed with a plurality of slots 31 at appropriate intervals, and magnetically in contact with the respective outer peripheral pieces to laminate a plate-like magnetic material with the shaft in the circumferential direction to form a second core portion. The core part 33 is formed.

An armature coil 35 wound in a ring shape as shown in FIG. 4 is inserted into the slot 31 provided between the first core portion 29 and the first core portion 29. An AC power supply (not shown), for example, a three-phase AC power supply using a three-phase inverter is connected to the armature coil. Although not shown, a position detector for detecting the position of the mover 11 is provided at an appropriate place, and a three-phase inverter is controlled based on the detected data to control the current of the armature coil. Can also.

Since the first embodiment is constructed as described above, it operates as follows. That is, the armature coil 3
When an alternating current is passed through 5, a magnetic field is generated as shown by the dotted line in FIG. Since this magnetic field moves in the axial direction of the movable shaft, an axial thrust is generated by the magnet provided on the movable shaft. Further, since the armature core and the mover are provided symmetrically with respect to the axis center, the suction force in the direction perpendicular to the axis is uniform, and is not particularly biased to one side.
Also, no rotational force is generated. Therefore, by appropriately controlling the alternating current, the speed and position of the movable shaft in the axial direction can be freely controlled, and in addition, the rotational direction can be controlled externally independently of the driving device.

Further, the armature core according to the present invention is formed by a first core portion and a second core portion as shown in FIG.
Since each core portion is formed by laminating plate-shaped magnetic bodies in the direction of the flow of the lines of magnetic force generated by the armature coils, the leakage magnetic flux is small and the magnetic resistance is small. Therefore, energy loss is small and heat generation is small.

FIG. 8 shows the configuration of the second embodiment of the present invention. This embodiment is almost the same as the first embodiment. Hereinafter, only different points will be described. The same parts are given the same numbers. In the first implementation,
As shown in FIG. 1, there is no first core portion mounted above the armature coil in the stroke direction of the mover, and when the outer diameter of the armature coil is small, there is a problem that a gap is formed. In this embodiment, as shown in FIG. 9, the diameter of the inner circular hole is larger than the inner diameter of the first core portion, and the outside of the plate-shaped magnetic body having the same shape as the polygon is formed in the upper portion of the slot. Thus, a third core portion 53 laminated in the stroke direction was provided outside the armature coil 51.

The present embodiment is configured as described above, and an armature core having a small magnetic loss is formed even when the outer diameter of the armature coil is small.

FIG. 10 shows a schematic configuration of a third embodiment of the present invention. In FIG. 10, a mover 51 has a movable shaft 53 and a ring-shaped magnet 53 shown in FIG.
Are arranged. The magnet is radially magnetized and has an N pole on the outside in FIG. 10, but may have an S pole on the outside.

The armature core 61 is configured as follows. That is, a yoke core made of a plate-shaped magnetic body having a polygonal shape (octagonal in this embodiment) having a hole into which the movable shaft can be inserted at the inner side shown in FIG. A laminated yoke portion 63 is provided, and at an appropriate position corresponding to the intermediate magnet, there is provided an inner hole having the same outer shape as the yoke core and an inner diameter that allows the magnet to be inserted, as shown in FIG. A plurality of first core portions 65 in which plate-like magnetic materials are stacked in the stroke direction are provided at appropriate spaces, and outside these spaces, the outer shape as shown in FIG. A plate-shaped magnetic body having a circular hole having a diameter larger than the inner diameter of the first core portion is laminated in the stroke direction to provide a third core portion. Plate-like magnetic material as shown in FIG. Constituting the second core portion 69 are stacked in a circumferential direction of the movable shaft 53. The armature core 6
1 is a first core part 65, a second core part 67, a third core part 69
And the yoke 69.

Armature coils 71a and 71b wound in a ring shape as shown in FIG. 11 (E) are inserted into slots formed by the first core portion 65 and the third core portion 69. Further, a DC power supply is connected to the armature coils 71a and 71b. By using a plurality of DC power supplies, the direction of the current in the left portion 71a and the direction of the current in the right portion 71b of the coil are reversed, or the winding of the coil is reversed, for example, the directions of the magnetic force lines are reversed as shown in the figure. It is constituted so that it becomes. Further, the DC power supply can be controlled by providing a position detector for detecting the position of the mover. Since the third embodiment is configured as described above, by controlling the direct current, the shaft propulsion force of the armature core 61 in the stroke direction is controlled, and the shaft position and the shaft speed can be controlled.

[0024]

As described above, according to the present invention,
A practical cylindrical linear motor that generates less heat can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the overall configuration of a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a permanent magnet used in the first embodiment.

FIG. 3 is a view showing a shape of a core material of a first core portion of the permanent magnet used in the first embodiment.

FIG. 4 is a diagram showing an armature coil of a permanent magnet used in the first embodiment.

FIG. 5 is a diagram showing a cross section of an armature core of a permanent magnet used in the first embodiment.

FIG. 6 is a diagram showing a configuration of a first embodiment using the present invention.

FIG. 7 is a diagram showing a flow of lines of magnetic force by an armature coil.

FIG. 8 is a diagram schematically showing the entire configuration of a second embodiment of the present invention.

FIG. 9 is a view showing a core material of a third core portion used in the second embodiment.

FIG. 10 is a diagram showing an outline of the entire configuration of a third embodiment of the present invention.

FIG. 11 is a view showing the shapes of main parts used in the third embodiment.

FIG. 12 shows a conventional flat-plate linear motor.
It is a figure showing an example.

FIG. 13 is a diagram showing an example of a conventionally known cylindrical linear motor.

[Explanation of symbols]

 Reference Signs List 5 linear motor 6 connecting means 7 rotating motor 11 mover 13 movable shaft 15, 15a, 15b permanent magnet 21, 61 armature core 29, 63 first core 31, 31, second core 53, third core 35, 51 , 71a, 71b Armature coil

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-49-133811 (JP, A) JP-A-48-12413 (JP, A) JP-A-47-40108 (JP, A) 63087 (JP, U) Shokai 63-63088 (JP, U) Shokai 61-65028 (JP, U) JP-B 54-43164 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 41/00-41/035 H02K 1/00-1/16 H02K 15/00-15/02 H02K 15/04-15/16

Claims (5)

(57) [Claims] 1. A mover in which a ring-shaped permanent magnet radially magnetized is mounted on a movable shaft with an even number of poles, and a plate-like magnetic body having a circular hole inside which is larger than the outer shape of the permanent magnet and having a polygonal outer surface. A plurality of first core portions laminated in the stroke direction of the mover, and a second core portion formed by laminating a plate-like magnetic material in a circumferential direction of the mover around an outer peripheral portion of the first core portion. An armature core, a slot between the first core portion and the first core portion, a ring-shaped armature coil inserted into the slot, and an AC current flowing through the armature coil. A cylindrical linear motor characterized by having a power supply. 2. The armature core further includes a circular hole having an inner diameter larger than an outer diameter of the armature core at a radially outer portion of the slot, and an outer shape having the same shape as the plate-shaped magnetic body. The cylindrical linear motor according to claim 1, wherein a third core portion is provided by laminating plate-shaped magnetic members in a stroke direction of the mover. 3. A mover in which a ring-shaped permanent magnet magnetized radially is mounted on a single pole on a shaft, and a plate-shaped magnetic body having a circular hole larger than the outer shape of the permanent magnet on the inside and a polygonal shape on the outside. An armature having at least a plurality of first core portions laminated in the stroke direction of the mover, and a second core portion laminated on the outer peripheral portion of the first core portion with a magnetic plate in a circumferential direction of the mover. A core, at least two or more ring-shaped armature coils inserted into slots provided between the first core portion and the first core portion, and a DC current flowing through the armature coil; A cylindrical linear motor characterized in that power supplies for generating magnetic fields in opposite directions are provided on the right and left sides. 4. The cylindrical linear motor according to claim 1, wherein a rotary drive device is provided on the movable shaft. 5. The cylindrical linear motor according to claim 1, further comprising a position detector for detecting the position of the mover, and being used as a linear servomotor.