JP2534062Y2 - Brushless DC 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 brushless DC linear motor.

[0002]

2. Description of the Related Art Conventionally, in a moving magnet type brushless DC linear motor, for example, as shown in FIGS. 5A and 5B, a magnet position detection signal by a pair of magnetic detection elements 40 and 41 is taken out to the outside. This is used as a position or speed signal of the movable element 42 which moves as shown by a broken line in the figure. The magnetism detecting elements 40 and 41 are
This is to detect the magnet position of the mover 42 composed of the yoke 46 and the yoke 46. Then, the magnetic detection elements 40 and 41
Operates when the magnetic flux density in the vertical direction becomes larger than the specific value B _S. In addition, the magnetic detecting element 4
Reference numerals 0 and 41 are arranged on the center lines of the winding portions 44a of the plurality of flat coils 44 arranged in a row as a stator. As a result, the energizing direction to the flat coil 44 is switched with good timing according to the relative position and the speed with respect to the mover 42 by the magnet position detection signals of the magnetic detection elements 40 and 41.

In the case where the permanent magnets 45 are provided on the magnetic detecting elements 40 and 41, focusing on the vertical magnetic flux applied to the magnetic detecting elements 40 and 41, first, the movement of the permanent magnet 45 shown in FIG. The magnetic flux generated from the permanent magnet 45 on the front magnetic detection element 40 with respect to the direction F,
With 5 flux respective vertical component generated in the flat coil 44 itself by energizing the I ₁ direction (A) in order to generate a thrust in the direction B _M, and B _C, B _M and B _C are the same direction It is. Further, if the vertical component of the magnetic flux on the magnetic detection element 40 due to the energization of the flat coil 44 is B _T , then B _T is B _T
Since B _C is added to _M , it becomes larger than the specific value B _S , and the magnetic detection element 40 operates stably. On the other hand, the magnetic detection element 4 on the rear side with respect to the movement direction F of the permanent magnet 45 shown in FIG.
1, the vertical components B _M and B of the magnetic flux generated from the permanent magnet 45 and the magnetic flux generated in the flat coil 44 itself by energization in the I ₂ direction in FIG. _C is the reverse direction, and the vertical component B _T of the magnetic flux on the magnetic detection element 41 due to energization of the flat coil 44
Becomes | B _T | = | B _M | − | B _C |, and B _T falls below the specific value B _S , so that the rear magnetic detection element 41 generates chattering.

Therefore, in order to prevent chattering from occurring, it is sufficient to dispose the flat coil 44 at a position where the magnetic flux generated in the flat coil 44 itself by energizing the flat coil 44 becomes 0 (zero). However, when an electric current is applied to the flat coil 44 in the direction I as shown in FIG. 6A, the direction of the magnetic flux (perpendicular to the flat coil 44) generated in the flat coil 44 itself is different from the direction of the magnetic flux generated in the flat coil 44 itself. When the magnitude is represented by an arrow, the distribution is as shown in FIG. 6B. At that time, the value of the magnetic flux on the magnetic sensing elements 40 and 41 does not become 0 (zero), and the point 50 where it becomes 0 is conventionally arranged. It is located outside from above the magnetic detection elements 40 and 41 which were previously. The magnetic flux 0 line 51 connecting the points where the magnetic flux becomes 0 on the flat coil 44 becomes as shown by a two-dot chain line in FIG. 6C. When the magnetic detection elements 40 and 41 are arranged on the magnetic flux 0 line 51, the timing of detecting the magnet position of the mover 42 for switching the direction of energization to the flat coil 44 is shifted.

Therefore, since the magnet position detection signal from the magnetic detection element 41 on the rear side with respect to the moving direction of the mover 42 is affected by chattering, it is difficult to accurately detect the position or speed signal of the mover 42. There was a problem. Further, at the time of operation, there is a problem that an unpleasant operation sound is generated due to intermittent switching of the energizing direction to the flat coil 44 due to chattering.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to eliminate an unpleasant operation sound and accurately position a movable element. Another object is to provide a brushless DC linear motor capable of detecting a speed signal.

[0007]

As shown in FIG. 1, a specific means for achieving the above object is a guide rail (1).
A plurality of flat coils (1
1) and a stator (10) having magnetic sensing elements (16a, 16b) respectively disposed on the winding portions (11a, 11b) before and after the air core of the flat coil (11).
And a permanent magnet (2) from both sides of the stator (10).
And a mover (20) arranged so as to correspond to the permanent magnets (22, 22) of the flat coil (11).
Relative to the magnetic detecting elements (16a, 16b)
In the movable magnet type brushless DC linear motor that switches the direction of energization to the flat coil (11) so that the mover (20) moves in a fixed direction upon detection, the winding portion of the flat coil (11) The front and rear corners of (11a, 11b) are inclined inward, respectively, and the center line of the winding section at the inclined section and the magnetic flux generated in the winding section when energized become 0 (zero). The magnetic sensing element on the intersection with the position row
(16a, 16b) is provided, and a brushless DC linear motor is provided.

[0008]

In the brushless DC linear motor configured as described above, since the corners of the flat coil (11) are inclined inward, respectively, the flat coil (1) is energized.
The position where the magnetic flux generated in the winding portions (11a, 11b) of 1) becomes 0 (zero) is also inclined. Then, the magnetic sensing element (16a,
16b) is arranged on the intersection of this position row and the center line of the winding portion at the inclined portion of the flat coil (11), so that the magnetic detection elements (16a, 16b) are energized in the direction in which the flat coil (11) is energized. Irrespective of the above, it is not affected by the magnetic flux generated in the flat coil (11) itself. Further, the magnetic detecting elements (16a, 16b) operate stably without shifting the timing of detecting the magnet position of the mover (20), and do not generate chattering.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. The brushless DC linear motor of the present invention has a main feature in that the position of the magnetic detecting element and the effect of the magnetic flux generated in the flat coil itself on the magnetic detecting element can be eliminated. The motor is
As shown in the cross-sectional view of FIG. 1, the guide rail 1 includes a stator 10 and a mover 20 disposed inside the guide rail 1. The guide rail 1 is a mold material such as aluminum, and is formed to have a substantially 断面 -shaped cross section with an open lower surface.

The stator 10 has the number of flat coils 11 cascaded corresponding to the length of the guide rail 1. Each flat coil 11 is hermetically surrounded and held by fixing members 12 and 13 made of a mold material such as aluminum.
To form a T-shaped overall shape. On the circuit board 14, an electronic control circuit 15 is arranged for each flat coil 11 and a predetermined connection is made as shown in FIG. As shown in FIG. 2, a pair of Hall elements 16a and 16b, which are magnetic detecting elements, are arranged in each flat coil 11 in a dimensional relationship described later. The stator 10 configured as described above is inserted into the space of the guide rail 1, and the column portion of the flat coil 11 is positioned at the center of the space of the guide rail 1.

The mover 20 uses a yoke formed in a substantially U-shaped cross section as a mover body 21 and arranges a plurality of permanent magnets 22 in the longitudinal direction on opposing inner surfaces to form a magnetic circuit. I do. The permanent magnets 22 and 22 that are adjacent to each other and those that face each other have the opposite polarity, and form a uniform magnetic field between the facing permanent magnets 22 and 22. Running rollers 31 are attached to both outer sides of the mover body 21 so that the mover 20 can move freely. The mover 20 configured as described above is inserted into the guide rail 1. At this time, the flat coil 11 of the stator 10 is located between the magnet gaps of the permanent magnets 22 arranged opposite to each other on the inner surface of the yoke.
Note that the number of permanent magnets 22 arranged on the mover 20 is determined by a necessary thrust.

FIG. 2 shows the dimensions and positional relationship of the flat coil 11 and the positional relationship between the Hall elements 16a and 16b when the magnetic pole pitch of the permanent magnet 22 disposed on the mover 20 is 2L. Each of the flat coils 11 has a length L of the winding portions 11a and 11b before and after the longitudinal direction, an air core portion having a length L at the center thereof, and a total length of 3L. It is arranged at intervals. In addition, the winding part 1
The outer corners on the upper end side of each of 1a and 11b are inclined at a predetermined angle toward the center of the air core, and are formed so as to have an inclination angle θ ₁ with respect to the front surface or the rear surface. Winding part 1
1a, the inner corner of each of the upper end of the 11b are formed to have a small inclination angle theta ₂ than the inclination angle theta _1.

The Hall elements 16a and 16b are provided with a center line (a dashed line in the drawing) of the winding portions 11a and 11b having a length L, and a position row (shown in FIG. (A two-dot chain line). Then, the distance between the corresponding positions is 2L.
In addition, the distance from the front surface or the rear surface is set to L / 2.

FIG. 3 is a schematic block diagram of the electronic control circuit 15. A drive IC 16 is connected to each flat coil 11, and based on a signal from a direction switching circuit 17 for switching the direction of a current supplied to the flat coil. Power is supplied to the flat coil 11. Hall ICs 18a and 18b that amplify and output detection signals of the Hall elements 16a and 16b, which are magnetic detection elements, are connected to the direction switching circuit 17. Hall IC 18
a, 18b detect the magnetism of the permanent magnet 22 of the mover 20, output a signal to the direction switching circuit 17, and output a signal from the direction switching circuit 17 to the drive IC 16 based on the signal.
The coil 11 is energized so that a force in a certain direction is generated according to the polarity of the permanent magnet 22. The switching of the driving direction is performed by outputting a direction control signal to the direction switching circuit 17. The signals from the holes 18a and 18b can be used as position signals. Power is supplied to the drive IC 16 from a power supply circuit (not shown).

The operation based on the above configuration will be described. In FIG. 2, when the mover 20 is moved in the illustrated F direction, when the flat coil 11 is not energized and the permanent magnet 22 approaches the Hall element 16a, the vertical component B _T of the magnetic flux on the Hall element 16a is Since the flat coil 11 itself does not generate a magnetic flux in a non-energized state, it becomes equal to the vertical component B _{M of the} magnetic flux generated from the permanent magnet 22. Therefore, B _T
Becomes larger than the specific value B _S and the Hall element 16a is turned on. The detection signal of the Hall element 16a is a Hall IC 18a
And output to the direction switching circuit 17. Power is supplied to the drive IC 16 from a power supply circuit according to a signal from the direction switching circuit 17. Then, the flat coil 11 is energized to I ₁ direction of Figure 2, the thrust of the F direction is generated in the mover 20 based on Fleming's left-hand rule. Therefore, when it is energized in a flat coil 11, but the magnetic flux is generated in the flat coil 11 itself, the permanent magnets on the vertical component B _C Hall elements 16a on the Hall elements 16a 22
The same direction as the vertical component B _{M of the} magnetic flux generated from
Since the Hall element 16a is disposed at a position where the magnetic flux generated in the flat coil 11 itself becomes zero, the Hall element 1
6a operates stably.

Next, when the flat coil 11 is not energized and the permanent magnet 22 approaches the Hall element 16b, the vertical component B _T of the magnetic flux on the Hall element 16b is
1 itself does not generate a magnetic flux in a non-energized state, so the permanent magnet 2
2 is equal to the vertical component B _{M of the} magnetic flux generated from Therefore, B _T becomes larger than the specific value B _S , and the Hall element 16
b turns ON. The detection signal of the Hall element 16b is amplified by the Hall IC 18b and output to the direction switching circuit 17. Power is supplied to the drive IC 16 from a power supply circuit in accordance with a signal from the direction switching circuit 17, and the drive IC 16
16 in turn energizes the I ₂ direction in FIG. 2 in a flat coil 11. Therefore, a thrust in the F direction is generated in the mover 20 in the same manner as described above, and the mover 20 continues to move in the same direction.
Then, when the flat coil 11 is energized, the flat coil 1
1 itself, the vertical component B of the magnetic flux generated from the permanent magnet 22
_Although a magnetic flux in the opposite direction to _M is generated, the Hall element 16b
The Hall element 16b does not generate chattering because it is arranged at a position where the magnetic flux generated in the flat coil 11 itself becomes zero and operates stably.

The switching of the energizing direction to each of the flat coils 11 corresponding to the permanent magnets 22 of the mover 20 is performed by using the Hall elements 16a and 16b by the winding portions 11a and 1 of the flat coil 11.
Since it is arranged on the center line of 1b, the magnet position is detected with good timing according to the moving speed of the mover 20.

Conversely, when moving the mover 20 in the direction opposite to the above-described F direction, the Hall element 16a or 16
Based on the detection signal output by b, a current in the opposite direction to that described above may be supplied to the flat coil 11.

According to the present invention, as shown in FIG.
Although the shape of FIG. 1 is changed, the thrust generated in the mover 20 is perpendicular to the current lines of the winding portions 11 a and 11 b of the flat coil 11. Therefore, in the inclined region 11c shown by oblique lines in FIG. 4, the thrust in the moving direction of the mover 20 is reduced with respect to the conventional flat coil shown in FIGS. However, even in the flat coil 44 having the conventional shape, the magnetic flux generated from the permanent magnet 22 of the mover 20 near the inclined region 11c is small, and the thrust generated in the flat coil 44 by energization is also small. Few.

[0020]

According to the present invention, the front and rear corners on one side of the winding portion side surface of the flat coil are inclined inward, respectively, and the winding is energized with the winding center line at the inclined portion. Since the magnetic detection element is arranged at the intersection with the position row where the magnetic flux generated in the line portion becomes 0 (zero), the position or speed signal of the mover without chattering can be obtained,
It is possible to accurately detect the position or speed signal of the mover, and to provide an excellent effect that no unpleasant operation noise is generated.

[Brief description of the drawings]

FIG. 1 is a sectional view of a movable magnet type brushless DC linear motor.

FIG. 2 is an explanatory diagram showing dimensions and a positional relationship of a flat coil and a positional relationship of a Hall element.

FIG. 3 is a schematic block diagram of an electronic control circuit.

FIG. 4 is an explanatory diagram of the effect of thrust on a mover due to the shape of a flat coil.

FIG. 5 is an explanatory diagram showing a positional relationship between a stator and a mover in a conventional movable magnet type brushless DC linear motor.

FIG. 6 is an explanatory diagram showing a magnetic flux generated in the flat coil itself.

FIG. 7 is an explanatory diagram showing a relationship between a magnetic flux generated from a permanent magnet and a magnetic flux generated in a flat coil itself.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Guide rail, 10 Stator, 11 Flat coil, 11a, 11b winding part, 16a, 16b Hall element (magnetic detection element), 20 Mover, 22, 22,
permanent magnet.

Continuation of front page (56) References JP-A-2-290152 (JP, A) JP-A-2-131353 (JP, A) JP-A-60-162472 (JP, A) JP-A-62-207168 (JP) JP-A-62-207169 (JP, A) JP-A-61-46893 (JP, U) JP-A-3-113983 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A stator having a plurality of flat coils arranged in a longitudinal direction in a space in a guide rail, and a magnetic detecting element disposed in a winding part before and after the air core part of the flat coils. And a mover arranged so that permanent magnets are made to correspond to the stator from both front and back sides, and the relative position of the flat coil with respect to the permanent magnet is detected by the magnetic detection element, and the mover moves in a fixed direction. In a movable magnet type brushless DC linear motor that switches the direction of current flow to the flat coil so as to move, the front and rear corners of one side of the winding portion of the flat coil are inclined inward, respectively. Characterized in that the magnetism detecting element is arranged at the intersection of the center line of the winding portion of the above and a position row where the magnetic flux generated in the winding portion by being energized becomes 0 (zero). Linear motors.