JPS6327946B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a linear motor in which a field magnet side is used as a moving element, an armature coil side is used as a stator, and the moving element is caused to reciprocate linearly.

2. Description of the Related Art Rotary motors and the like that perform rotational motion are generally known as devices for moving objects. Needless to say, what is frequently used in these devices is a rotary motor that performs rotational motion for multiple purposes. However, in order to cause an object to make linear reciprocating motion using a motor that performs this rotational motion, a converter is required to convert the rotational kinetic energy into linear reciprocating energy. Therefore, the linear reciprocating drive device has a complicated structure and is expensive. In this way, various highly efficient motors have been developed to drive objects, but in order to move objects in a straight line, linear motors, which directly perform linear motion, are more effective than motors that perform general rotational motion. In many cases, this is preferable, and the effectiveness of this linear motor has been praised for a long time. Inventions and ideas using linear motors in various fields, such as linear motor cars using linear motors, door opening/closing devices, camera shutter opening/closing devices, linear drive devices for copying machines, drafting tables, etc., are well known. However, most of these linear motors are linear induction motors, linear pulse motors, or voice coil linear motors. Linear induction motors are large and expensive, and cannot be driven using a DC power source, making them unsuitable for small devices. Linear pulse motor is
It has the drawback of large mechanical vibrations and loss of synchronization when driven at high speeds. Furthermore, with a linear pulse motor, the stator teeth must be finely formed over the entire moving path of the moving element, which is very expensive, and the stroke length of the moving element must be changed to a longer length as necessary. He is a strong man. A voice coil type linear motor is used to drive the head of a magnetic disk, and although it has the advantage of being extremely compact, it has the disadvantage that the magnetic circuit is complicated and the stroke length of the mover cannot be increased.

For this reason, a linear DC motor is in demand. Such linear DC motors are (1) useful for small devices because they can be driven by a DC power supply, (2) have a large starting torque (thrust), and (3) are more efficient than linear pulse motors, etc. Yes, (4)
You can freely design circuits from low speed to high speed. For example, in circuit design, like a linear pulse motor,
It can also be driven in steps, (5) it does not cause step-out even when the mover is running at high speed, (6) there is little mechanical vibration, and (7) it requires remarkable machining accuracy similar to that of a linear pulse motor. It has the advantage of not being However, most conventional linear DC motors are of the iron core type having a stator iron core. For this reason, (1) it is difficult to arrange the position detection element, and (2) it is difficult to run smoothly because it has a large cocking because it is a iron core type. (3) Since it is a ferrous core type, it attracts each other with the field magnet, and as a result, it is necessary to use rigid and expensive support mechanisms such as bearings and wheels to support the mover. The disadvantages are the same for linear induction motors and linear pulse motors.) (4) Because they are iron core types, they are heavy, difficult to assemble, and expensive.
(5) Even if an attempt is made to change the stator to one with a longer stroke if necessary, there is a drawback in that the stator cannot be easily added to a longer stroke.

The linear motor of the present invention is a movable magnet type linear DC motor developed based on the above circumstances, and is capable of (1) obtaining large thrust (torque), (2) good efficiency, and (3) being flexible from low to high speeds. (4) The position detection element for detecting the N pole or S pole of the field magnet and energizing the armature coil in the desired direction can be easily installed at a desired position; (5) The air core By using a type armature coil, coking can be minimized, resulting in smooth running.
(6) Inexpensive support mechanisms such as bearings and wheels that support the slider can be used; (7) stroke lengths can be easily changed to various lengths as needed; (8)
It is light in weight, has a small number of parts, and can be mass-produced at low cost. (9) It has good efficiency by using a 180 electrical degree energization method that switches energization at intervals of the width of one magnetic pole of the field magnet. (10) To obtain a linear motor that can obtain a large thrust, has a simple control method, and has a simple electric circuit configuration; (10) It is possible to rationally store electric components such as a drive circuit in the hollow space within the frame of the armature coil. (11) In linear motors that move the slider over a long stroke, use an armature coil with a large opening angle in areas that do not require large thrust, and use an armature coil with a large opening angle in areas that require large thrust. By making it possible to select armature coils with small opening angles, it is possible to reduce the number of armature coils arranged in the magnetic circuit, and to easily form a linear motor at low cost. 12) The position sensing element is not placed in a position facing the conductor part that contributes to the thrust of the armature coil, but is placed in the cavity within the frame of the armature coil, and it can be efficiently detected at an electrical angle of 180 degrees. The purpose was to obtain a linear motor that could be energized. Incidentally, as a linear motor using an air-core armature coil as in the present invention, Japanese Patent Laid-Open No. 53-
As disclosed in No. 147219, such a linear motor simply has a position sensing element disposed in the cavity within the frame of the armature coil, so it is efficient and can obtain a large thrust. It has become impossible to adopt the 180-degree electrical angle energization method, which has many advantages.

An object of the present invention is to use a field magnet as a mover, which has a plurality of magnetic poles each having a width of T, N pole and S pole, so that adjacent magnetic poles along the longitudinal direction of the mover have different polarities. , the opening angle of the conductor contributing to the thrust at the fixed side position facing the field magnet through the air gap is T. (2n-1) (However,
n: An integer of 2 or more This is achieved by arranging the position sensing element at a fixed side position that is spaced from the conductor portion by the width T in the moving direction of the movable element so as not to overlap the armature coil.

Embodiments of the present invention will be described below with reference to the drawings.

The stator 1 mainly includes a stator yoke 2 made of a magnetic material such as an iron plate, a rectangular frame-shaped (air-core type) armature coil 3, a position detection element 4 such as a Hall element, and a necessary electric circuit 5. Stator yoke 2 on long plate
A plurality of rectangular frame-shaped armature coils 3, 3, . There is. It is useful to insulate one side of the stator yoke 2 and form the necessary printed power distribution pattern on it, but it is also useful to fix the three groups of armature coils on the stator yoke 2 using a printed circuit board. It's okay. In addition, rectangular frame armature coils 3 and 3
The intervals between the two do not necessarily have to be equal intervals. That is, sufficient thrust (torque) can be generated with one rectangular frame-shaped armature coil 3, and when the mover 9 reaches the next armature coil 3, the next rectangular frame-shaped armature coil 3 is excited. If current is applied at the same time, mover 9
This is because the stator 1 can be moved smoothly in a straight line, and the stator 1 can be lengthened depending on the purpose. When the stator yoke 2 is connected to another stator yoke 2 to increase the length of the stator yoke 2. This is because it cannot be said that the intervals between the rectangular frame-shaped armature coils 3 are necessarily equal. Similarly, the stator yoke 2 does not necessarily have to be in the form of one long plate, and it is sufficient if one armature coil 3 in the form of a rectangular frame is fixed to one stator yoke 2. That is, this is to make it easier to increase the length of the stator 1 depending on the purpose. Therefore, the stator yoke 2 has a size that allows only one rectangular frame-shaped armature coil 3 to be fixed thereto, and only one rectangular frame-shaped armature coil 3 is fixed to the stator yoke 2. and make it one block (unit),
These blocks may be arranged to form one long plate-shaped stator 1. Since it is possible to do this, the intervals between the rectangular frame-shaped armature coils 3 do not necessarily have to be equal as described above. The rectangular frame-shaped armature coil 3 is an air-core type in which a coil is wound in a rectangular frame shape with many turns. but,
It goes without saying that the armature coil 3 may be formed by printed wiring. In this embodiment, the armature coil 3 has a rectangular frame shape, but
It does not necessarily have to be a rectangular frame shape. That is, it may be a frame-shaped air-core type based on appropriate design specifications. It is convenient to form the armature coil 3 using self-welding wire. Each of the rectangular frame-shaped armature coils 3 has two terminals 6 taken out for connection to the positive side and the negative side.
This terminal 6 is connected to an energization control circuit (not shown) (necessary electric circuit 5) via the above-mentioned printed power distribution pattern (not shown). Armature coil 3
Conductor portions 3d and 3e perpendicular to the moving direction of the mover 9
is a conductor portion that contributes to thrust (torque), and the conductor portion 3 is parallel to the moving direction of the mover 9 of the armature coil 3.
b and 3c are conductor portions that do not contribute to thrust. As is clear from the description below, the opening angle between the conductor parts 3d and 3e that contribute to the thrust is such that when T is the width of the negative magnetic pole of the N or S pole of the field magnet 11, which will be described later. It is an air-core type with a frame approximately equal to T.(2n-1) (where n: a natural number of 2 or more) times. Note that the above opening angle is for the conductor parts 3d and 3e.
It is desirable to use the center of the conductor portion 3 as a reference.
Since d and 3e have a certain width, they may be slightly shifted. The position detection element 4 moves depending on whether the conductor parts 3d and 3e, which contribute to the above-mentioned thrust force and which face the armature coil 3 and the field magnet 11, face the north pole or the south pole. Since it is necessary to propel the child 9 in a predetermined direction, the fixed side facing the conductor parts 3d and 3e, such as the dotted line surrounding parts 15 and 16, is placed on the conductor part that contributes to the thrust of the armature coil 3. Positionally, it is desirable to place it in a certain position.

However, arranging the position sensing element 4 at such a position has various drawbacks. That is, when placed on conductor portions 3d and 3e that contribute to the thrust and face the field magnet 11 (to be described later), the field air gap 14 increases by the thickness of the element 4.
(See Fig. 2) is increased, making it impossible to obtain a large thrust force. Further, it is difficult to dispose the conductor portions 3d and 3e, which contribute to the thrust and face the field magnet 11, on the opposite surface, that is, at the position of the stator yoke 2. Therefore, as shown in FIGS. 1 and 2, a position detecting element 4 or a position detecting element 4 is disposed in the frame cavity 3a of the rectangular frame-shaped armature coil 3 so as not to overlap with the armature coil 3. This is useful because the above-mentioned drawbacks can be solved by accommodating the necessary electric circuit 5. The necessary electric circuit 5 is a drive current for passing an excitation current suitable for linearly moving the mover 9 in a predetermined direction through the rectangular frame-shaped armature coil 3 based on the signal from the position detection element 4. Control circuits, etc. In addition, protrusion 2
b and 2c are formed to protrude perpendicularly to the surface 2a, respectively, and are located at a predetermined distance apart from the conductor parts 3b and 3c that do not contribute to the thrust of the rectangular frame-shaped armature coil 3. It is provided parallel to 3c. The protrusions 2d and 2e are respectively protrusions 2
The protrusions 2b and 2c are provided in parallel in the same form as the protrusions 2b and 2c, and a groove is formed by the protrusions 2b and 2d, and 2c and 2e. A shaft 13 is horizontally suspended in this groove, and a roller 12 having a V-shaped groove 12a that engages with rails 7 and 8, which will be described later, is rotatably supported on the shaft 13. The rails 7 and 8 are provided parallel to a moving yoke 10 made of a magnetic material such as an iron plate and located a predetermined distance apart from end portions 11a and 11b of a field magnet 11, which will be described later. Mover 9
It mainly consists of a moving yoke 10 and a field magnet 11, which will be described later. The movable yoke 10 on the movable element side is slidably provided by the above-mentioned appropriate means so as to be positioned opposite to the stator yoke 2 forming the stator 1 at a constant distance from the stator yoke 2. There is. Field magnet 11
are arranged relative to the stator yoke 2 of the moving yoke 10. Further, at least the surface of the field magnet 11 facing the rectangular frame-shaped coil 3 is arranged at predetermined intervals alternately in the longitudinal direction (this is called the opening angle width or magnetic pole width of the field magnet 11, and this magnetic pole width will be referred to as (represented by the symbol T), and has a plurality of magnetized poles of N pole and S pole.

As described above, in the armature coil 3, when the width of one magnetic pole of the N pole and the S pole of the field magnet 11 is T, the opening angle between the two conductor parts 3d and 3e that contribute to the thrust is T. (2n-1) (where n is an integer of 2 or more) times the width, that is, the opening angle is an odd number times 3 or more. One of the reasons for this is that when one of the conductor parts 3d that contributes to the thrust of the armature coil 3 faces the N pole of the field magnet 11,
This is because unless the conductor portion 3e contributing to the other thrust is opposed to the S pole of the field magnet 11, a large thrust will not be generated. In addition, in order to widen the energization width of the armature coil 3 and generate sufficient thrust in a predetermined direction between the magnetic pole width T of the N pole or S pole of the field magnet 11, the armature coil 3 must be As shown by the dotted line, the relationship between the opening angle (magnetic pole) width T of the field magnet 11 and the winding width (coil width) t of the armature coil 3 may be such that T=t. Here, as described above, considering the armature coil 3 shown by the dotted line, the position detection element 4 is located at a position facing the conductor parts 3d and 3e that contribute to thrust (for example, the dotted line surrounding parts 15 and 17). Although it is desirable to arrange the armature coil in the frame cavity 3a of the armature coil 3 as shown in FIGS. 1 and 2, since it is difficult as described above, There's nothing wrong with this. In particular, the electric circuit 5 such as the energization control circuit together with the position detection element 4
(Incidentally, it would be even more convenient if this was implemented as an IC.) It is useful to have it built-in. However, if the width of the N pole or S pole of the field magnet 11 is narrow, the opening angle (width) T of the armature coil 3 shown by the dotted line must also be made small, and the space within the frame of this armature coil must be made small. A position detection element 4 and an electric component 5 are installed in the body 3a.
There are limits to how much space can be placed. That is, the armature coil 3 has an opening angle T (=t) that is approximately equal to the magnetic pole width T of the field magnet 11, as shown by the dotted line in FIG.
When the opening angle T (=t) is formed by the conductor portions 3d and 3e, the width formed by the conductor portions 3d and 3e becomes narrower. It becomes impossible to arrange it within the frame cavity 3a. Referring to FIG. 3, a conductor portion 3d that contributes to one thrust of the armature coil 3, indicated by a dotted line, has a N pole of the field magnet 11 and a non-pole (or this portion may become an S pole). The conductor portion 3e, which faces the other and contributes to the other thrust, faces the boundary between the N and S poles of the field magnet 11.

Therefore, referring to FIG. 3, the armature coil 3
is the opening angle between the conductor parts 3d and 3e that contribute to the thrust as shown by the solid line, and if the magnetic pole width of the N pole or S pole of the field magnet 11 is T, then the magnetic pole width T is an odd number. Even if the winding width (coil width) is doubled to 3t, the opening angle width t of the armature coil 3 shown by the dotted line above
is in the same phase as when T=t, so the same torque is generated. Therefore, armature coil 3
is the armature coil 3 with opening angle t shown by the dotted line in FIG.
Since the inner cavity 3a is formed with a width more than three times that of the armature, the position sensing element 4 or the position sensing element 4 and the necessary electric circuit 5 can be rationally It is desirable that the coil 3 can be housed and disposed within the frame cavity 3a of the coil 3. The opening angle of the armature coil 3 and the width of the opening angle of the frame cavity 3a are determined by storing and disposing the armature coil 3 inside the frame cavity 3a. It is advisable to determine this depending on the size of the necessary electric circuit 5, etc. In order to do this, when the magnetic pole width of the N pole or S pole of the field magnet 11 is T, and the coil width t of the armature coil 3 is t, the coil of the armature coil 3 in the rectangular frame shape is The width t is the coil width t=T・(2n-1)
(However, it is good to set n=2,...,n) as follows:
As mentioned above. When the coil width of the armature coil 3 is 3t as shown in FIG. 3, the position detection element 4 is arranged, for example, at a position surrounded by dotted lines 15 or 16, facing the conductor portion 3d or 3e that contributes to thrust. It is desirable to have a However, when disposed in this position, there is a drawback that the field air gap 14 increases by the thickness of the position sensing element 4 as described above. Therefore, for the armature coil 3 having a coil width of 3t, for example, the dotted line surrounding portion 16 facing the conductor portion 3e that contributes to the thrust of the armature coil 3
The position sensing element 4 disposed at the position is connected to the coil width t, that is, the magnetic pole width T, from the conductor portion 3d contributing to the thrust.
The above-mentioned drawbacks can be solved by arranging the dotted line enclosing part 17 within the frame hollow part 3a of the armature coil 3, which is shown by the solid line, and which is separated by a certain distance. in this way,
In FIG. 3, the armature coil 3 shown by the solid line has an opening angle that is an odd number multiple of 3 or more of the armature coil 3 shown by the dotted line.
It is also very useful because the necessary electrical components 5 can be stored and arranged in a rational manner.

Although the position detection element 4, which should be disposed at a position facing the conductor portion 3e that contributes to the thrust, is disposed at the position of the dotted line enclosing portion 17, no problem occurs because the phases are the same. Further, it may be arranged at the position of the dotted line surrounding portion 18, which is shifted by the magnetic pole width T from the conductor portion 3d that contributes to the thrust force. This is because the position of the dotted line surrounding portion 18 is in phase with the dotted line surrounding portions 16 and 17. However, there is a drawback that the position sensing element 4 cannot be accommodated within the frame cavity 3a of the armature coil 3 at the position surrounded by the dotted line 18. Further, the position detection element 4 is disposed at a position facing the conductor portion 3d that contributes to the thrust of the armature coil 3, for example, at the position of the dotted line surrounding portion 15.
A dotted line enclosure 19 or 20 separated by the magnetic pole width T from
It should be placed in position. The dotted line surrounding parts 19, 20
This is because the position is in phase with the position of the dotted line encircling portion 15. When the position sensing element 4 is disposed at the position of the dotted line surrounding part 19, the hollow part 3 in the frame of the armature coil 3
Although the position sensing element 4 can be housed and arranged within a,
In the case of the dotted line enclosure 20 position, the armature coil 3
There is a disadvantage that it cannot be stored and arranged within the frame cavity 3a.

However, when the position sensing element 4 is disposed at the positions of the dotted line enclosures 18 and 20, sufficient space is formed in the frame cavity 3a of the armature coil 3, so that the necessary electric circuit 5 can be It has the advantage of being easy to store and arrange. Furthermore, even if the position sensing element 4 cannot be accommodated within the frame cavity 3a, there is no particular problem since it is not far away from the armature coil 3. In addition, when the position detection element 4 is arranged at the dotted line enclosure part 18 or 20 position, depending on the arrangement position of the other armature coil 3, the conductor part contributing to the thrust of the other armature coil 3 may be The field air gap 14 can be disposed at a position where it does not face each other, for example, at a position between the armature coil 3 and another armature coil 3, or at a position within the frame cavity 3a of another armature coil 3. This has the effect of eliminating the disadvantage of increasing In particular, the frame cavity 3 of the other armature coil 3
If it becomes possible to accommodate and arrange the position sensing element 4 in the dotted line surrounding portions 17 and 19
You can get the same benefits as if you placed it in the same position. If the position detection element 4 is disposed at the above position, the signal from the element 4 to the armature coil 3 is inverted for each magnetic pole width of the disclosure magnet 11, that is, for each energization of 180 degrees in electrical angle. The energization of the armature coil 3 is switched at intervals of .

As described above, the present invention employs a 180-degree energization method in which energization to the armature coil 3 is switched every 180 degrees, so a highly efficient linear motor can be obtained.

The linear motor of the present invention has the above configuration.

Therefore, when a current is applied to the drive current control circuit that constitutes a part of the necessary electric circuit 5 through a conductive rail (not shown) to operate it, the position sensing element 4 detects whether the S or N pole of the field magnet 11 is activated. When the position detection circuit in the necessary electric circuit 5 outputs this detection signal to the drive current control circuit, the mover 9 is determined to be in a direction suitable for linear movement in that direction. A current flows through the rectangular frame-shaped armature coil 3 through the terminal 6, and a moving magnetic field in a predetermined direction is generated at the adjacent north and south poles of the field magnet 11. According to Fleming's left-hand rule, the moving element 9 moves linearly in a predetermined direction.

As is clear from the above, the present invention has the following advantages: (1) The magnetic pole width T of the field magnet at the opening angle of the armature coil
Since it is multiplied by (2n-1), there is no counter torque,
(2) It is especially useful when the armature coils are arranged without overlapping. When the armature coils are arranged without overlapping, the field air gap can be made small and a large thrust can be obtained. (3) Since it is a linear DC motor, it has good efficiency. (4) Since it is a linear DC motor, it can be driven freely from low speed to high speed. (5) It is inexpensive because armature coil groups are not arranged in layers. A smooth thrust ripple can be obtained. (6) Since the opening angle of the armature coil is set to T·(2n-1) times the magnetic pole width T of the field magnet, the conductor part that contributes to the thrust of the armature coil Since the position sensing element can be easily placed in the cavity within the frame of the armature coil, which is in the same phase as the A linear motor with large thrust can be obtained because the increase in the field air gap is eliminated and a large magnetic flux is obtained. (7) A coreless type moving magnet type linear DC whose armature is formed by a group of air-core frame-shaped armature coils. Since it is a motor, it has good responsiveness, and since there is no iron core, coking can be minimized, allowing the slider to run smoothly. (8) Since there is no iron core, there is no need to wind the armature coil around this iron core, and armature coils can be mass-produced extremely easily and inexpensively. As a result, the iron core and field magnet do not attract each other, and extremely inexpensive support mechanisms such as bearings and wheels that support the slider can be used, and the assembly accuracy and configuration are extremely simple. (10) The position sensing element can be easily placed in the desired position; (11)
Since the necessary electrical circuits can be stored together with the position sensing element within the cavity within the frame of the armature coil, it is possible to form a small moving magnet type linear motor.
Since the armature coils equipped with position detection elements and necessary electric circuits in the cavity inside the frame can be made into a unit, many armature coils can be installed in areas where particularly large thrust is required, and in areas where large thrust is not required. Since the number of armature coils can be arranged accordingly,
Even if the mover or stator is lengthened depending on the purpose, the armature coil can be made into a unit, so it can be easily corrected accordingly. (12) In addition, the above-mentioned
As is clear from (11), it is easy to form a slider with a short or long stroke length, and (13) it does not use an iron core, that is, it is a coreless type, so it is light in weight and the magnetic circuit is simple. It is possible to obtain a movable magnet type linear DC motor that has a small number of parts and can be mass-produced easily and inexpensively. (14) Since it is a 180-degree energizing linear motor, it has good efficiency and a control method. It is also easy to use and can use commercially available motor ICs (15)
Furthermore, even if the position sensing element is housed in the cavity within the frame of the armature coil as described in (11) above, unlike the conventional method, the
This has the effect of providing a linear motor that can be energized frequently.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a stator of a linear motor according to the present invention, FIG. 2 is a longitudinal sectional view of the linear motor according to the present invention, and FIG. 3 is a developed view of a field magnet and an armature coil. Explanation of symbols: 1... Stator, 2... Stator yoke, 3... Rectangular frame-shaped armature coil, 3a... Hollow part in the frame, 3d, 3e... Conductor part contributing to thrust, 4...
Position detection element, 5... Necessary electric circuit, 9... Mover, 10... Moving yoke, 11... Field magnet.

Claims (1)

[Claims] 1. A field magnet having a plurality of N and S poles each having a width T such that adjacent magnetic poles along the longitudinal direction of the mover have different polarities is used as a mover. ,
The opening angle of the conductor contributing to the thrust at the fixed side position facing the field magnet through the air gap is T・( 2n-1) (however, n: an integer of 2 or more)
A stator is formed by arranging a plurality of double-sized air-core armature coils so as not to overlap with other armature coils, and from one conductor part contributing to the thrust of the armature coil to the above T width. A linear motor characterized in that a position detection element is arranged at a fixed side position that is far away in the direction of movement of a moving element so as not to overlap the armature coil. 2. The linear motor according to claim 1, wherein a position detection element and a necessary electric circuit are disposed within the frame cavity of the armature coil.