JPS6277052A - Linear pulse motor - Google Patents

Abstract

PURPOSE:To reduce the unevenness of interphase thrust, by setting the turn ratio of a pair of exciting coils arranged between the slider teeth of a respective movable tooth sections, so that the combined magnetic flux of flux through the respective slider teeth and flux due to a permanent magnet may be almost equal. CONSTITUTION:A pair of exciting coils 10-13 are arranged between the slider teeth 3-6 of a pair of movable tooth sections 7, 8 arranged in the arrangement direction of stator teeth 1. The turn ratio is set so that exciting flux generated on the slider teeth 3, 6 far from a permanent magnet 9 may be strong and exciting flux generated on the slider teeth 4, 5 near the magnet 9 may be weak. In other words, the turn ratio is set so that the sum of exciting flux through he respective slider teeth 3-6 and flux due to the magnet 9 may be almost equal. As a result, regardless of the distance from the magnet 9, thrust due to the attracting force of the respective slider teeth 3-6 is set to be same, and so the unevenness of interphase thrust can be reduced. Accordingly, stop precision is improved, and the unevenness of damping characteristic is also reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a linear pulse motor applied to a drive unit of a printer head, etc.

[Background technology]

Conventional examples are shown in FIGS. 3 to 5. That is, in FIG. 3, 50 is a stator, 51 is a stator tooth, 52 is a movable element, 53.54 is a movable tooth portion, 55 to 58 are slider teeth, 59 is a permanent magnet, and 60.61 is an exciting coil. . The stator teeth 51 and the slider teeth 55 to 58 face each other in a fixed relationship, and the excitation coils 60, 61 are controlled by a bipolar drive circuit shown in FIG. 6, so that the movable element 52 moves in steps. Tr1 to TrB are switching transistors, and a control signal is applied to the input terminal P.

Vcc is the coil excitation voltage.

In FIG. 4, a pair of excitation coils 60a, 60b, 61a, and 61b are provided for each movable tooth portion 53, 54, respectively, and are driven by a unipolar drive circuit as shown in FIG. −
r r, J to T r 4' are switching transistors, and a control signal P is applied to each base.

These linear pulse motors have slider teeth 55 to 58
When the stator teeth 51 are deviated by 1/4 pitch (the distance between the stake teeth 51 is 1 pinch), the permanent magnet 59 is excited in the same direction between the opposing teeth to propel the stator by 1/4 pitch. let

However, due to the permanent magnet 59, the slider teeth 55 to 5
The magnetic flux generated between the permanent magnet 59 and the stator tooth 51
The slider teeth 55 and 58 farther away from the permanent magnet 59 become smaller due to the increased magnetic resistance, and the slider teeth 56 closer to the permanent magnet 59 become smaller.
．． The magnetic flux of 57 increases. There is also the effect of magnetic flux leakage.

Therefore, even if the square slide teeth 55 to 58 are excited in the same direction as the magnetic flux by the permanent magnet 59 using the excitation coils 60 and 61, the resultant magnetic flux will still differ. As a result, the propulsive force varies from phase to phase, and the interphase thrust varies, resulting in poor stopping accuracy of the mover and variations in damping characteristics.

[Purpose of the invention]

An object of the present invention is to provide a linear pulse motor with less variation in thrust between phases, good stopping accuracy, and less variation in damping characteristics.

[Disclosure of the invention]

This invention includes a stator in which stator teeth are arranged in one direction;
a pair of movable tooth portions each having a pair of slider teeth facing the stator teeth and aligned in the row direction of the stator teeth and arranged in the row direction of the stator teeth; and a pair of movable tooth portions interposed between the movable tooth portions. A permanent magnet that mutually polarizes the movable tooth portions into violent magnetic poles, and a pair of excitation coils arranged between the slider teeth of each movable tooth portion to excite the slider teeth and having different numbers of turns from each other. , in a slider tooth far from the permanent magnet of each movable tooth portion and a slider tooth close to the permanent magnet, a composite magnetic flux of the magnetic flux of the permanent magnet and the magnetic flux of at least one of the excitation coils excited in the same direction as the magnetic flux of the permanent magnet is The present invention is characterized in that the turn ratios of the excitation coils are set to be approximately equal to each other.

According to this invention, the turns ratio of the pair of excitation coils in each of the movable tooth portions allows the excitation fft1 flux in the same direction as the magnetic flux of the permanent magnet of the slider tooth farthest from the permanent magnet to be strongly applied to the slider tooth near the permanent magnet. By weakening the excitation magnetic flux in the same direction as the magnetic flux of the permanent magnet, the composite magnetic flux including the magnetic flux of the permanent magnet can be made approximately equal. Therefore, the thrust between each slider tooth and stator tooth can be made the same, and the variation in thrust between phases can be reduced.
Stopping accuracy can be improved and variations in damping characteristics can be reduced.

Embodiment An embodiment of the present invention will be explained based on FIG. That is, this linear pulse motor includes a stator 2 having stator teeth 1 arranged in one direction, and a pair of slider teeth 3 to 6 facing the stator teeth 1 and aligned in the direction of the stake teeth 1.
A pair of movable tooth portions 7 and 8 are arranged in the row direction of the stator teeth 1, respectively, and a pair of movable tooth portions 7 and 8 are interposed between the movable tooth portions 7 and 8 so that the movable tooth portions 7 and 8 have mutually different magnetic polarities. a permanent magnet 9 that is polarized, and a pair of slider teeth 3 to 6 arranged between each of the slider teeth 3 to 6 of each of the movable tooth portions 7 and 8;
A pair of excitation coils 10 to 13 having different numbers of turns are provided, and a slider tooth 3.6 of each movable tooth section 7, 8 which is far from the permanent magnet 9 and a slider tooth 4.6 which is close to the permanent magnet 9 are provided. 5, the turn ratio of the pair of excitation coils 10 to 13 is set so that the magnetic flux of the permanent magnet 9 and the magnetic flux of at least one excitation coil excited in the same direction are approximately equal. It is a feature.

As in the conventional example, the stator teeth 1 have the same width and are arranged in rows at intervals equal to the width. The tooth width of the slider teeth 3 to 6 is also formed to be the same as that of the stator tooth 1, and the movable tooth parts 4 and 5 are formed in a U-shape with the slider teeth 3 to 6 at both ends, and the middle part of the movable tooth part 4.5 Excitation coils lO to 13 are each wound in a bifilar manner. Further, the excitation coil 10.11 has a larger number of turns than the excitation coil 12.13. The movable element is supported with respect to the stator 2 by, for example, rollers (not shown) so that the gear knobs between the slider teeth 3 to 6 and the stator teeth 1 have minute intervals. Also, slider teeth 3 to 6
For example, when the slider teeth 3 face the stator teeth 1, the slider teeth 4 are 1/2 pitch with respect to the stator teeth 1 (stator teeth 1).
The slider teeth 5 are shifted by 1/4 pitch in the direction opposite to the propulsion direction A in FIG. 1 with respect to the stator teeth 1, and the slider teeth 6 are shifted from the stator teeth 1. 1/4 in the same direction as the propulsion direction A in Figure 1.
Make sure they are off-center.

The excitation coils 10 and 11 and the excitation coils 12' and 13, which have the same number of turns, are driven by the same unipolar drive circuit as shown in FIG.
0.11 excites the slider teeth 3, 6 far from the permanent magnet 9 in the same direction as the magnetic flux direction of the permanent magnet 9, and the excitation coil 12.13 with a small number of turns excites the slider teeth 4.
A current of the same magnitude is applied to excite the permanent magnets 5 in the same direction as the magnetic flux direction of the permanent magnets 9. At this time, the excitation coil]
By appropriately setting the turns ratio of 0°11 and the excitation coil 12.13, the composite magnetic flux including the magnetic flux from the permanent magnet 9 flowing between the slider teeth 3 to 6 and the stator tooth 1 will be approximately the same. Set.

The excitation coil 10.11 and the excitation coil 12.13 are energized so that the phase is shifted by 90 degrees between the movable teeth 7.8 as shown in FIG. That is, in the state shown in FIG. 1, a pulse a is applied to the excitation coil I3 at time t1. As a result, the magnetic flux of the excitation coil 13 is added to the magnetic flux of the permanent magnet 9 between the slider teeth 5 and the stator teeth 1, and the attraction force causes the slider teeth 5 to move in the 1/4 pitch direction and face each other. This movement causes the slider teeth 4 to be shifted by 1/4 pitch in the opposite direction to the direction A with respect to the stator teeth 1. Pulse b is applied to the excitation coil IQ after a delay of 90 degrees, and an attractive force acts between the slider teeth 4 and the stator teeth 1, and the movable element further moves in the 1/4 pitch direction A. This movement causes the slider teeth 6 to be shifted by 1/4 pitch in the opposite direction to the direction A with respect to the stator teeth 1. Pulse C is applied to exciting coil 11 with a phase delay of 90 degrees with respect to pulse b, slider teeth 6 are attracted to stator teeth l, and the movable element moves by 1/4 pitch. At this time, the slider tooth 3 is in the direction A.
Since it deviates from the stator tooth 1 in the opposite direction, when the pulse d is applied to the excitation coil 12 90 degrees later than the pulse C, the movable element force q further increases by 1/4 pitch. In this way, the state shown in FIG. 1 is reached again, and the same operation is repeated to perform the step operation.

In such a step operation, each slider tooth 3 to 6
Since the sum of the excitation magnetic flux flowing through the slider and the magnetic flux due to the permanent magnet is almost the same, the thrust due to the attractive force of each slider tooth 3 to 6 becomes the same. Therefore, since there is little variation in mutual thrust, stopping accuracy is improved and variations in damping characteristics are reduced.

In addition, the excitation coil I 12 and the excitation coil 11
．． 13 individually, but by simultaneously applying current to both of them in the sum or difference direction, the slider teeth 3.
The excitation magnetic flux of the slider teeth 4.6 may be large and the excitation magnetic flux of the slider teeth 4.5 may be small, and control may be performed so that when the magnetic flux of the permanent magnet is added, the resultant magnetic flux becomes the same. In these cases as well, the number of turns that gives the same composite magnetic flux is appropriately set.

〔Effect of the invention〕

According to this invention, the turns ratio of the pair of excitation coils in each of the movable tooth parts causes the excitation magnetic flux in the same direction as the magnetic flux of the permanent magnet of the slider tooth farthest from the permanent magnet to be strongly applied, and the excitation magnetic flux of the slider tooth near the permanent magnet to be strongly applied. By weakening the excitation M1 magnetic flux in the same direction as the magnetic flux of the permanent magnet, the composite magnetic flux including the magnetic flux of the permanent magnet can be made approximately equal. Therefore, the thrust between each slider tooth and the stator tooth can be made the same, and variations in the thrust between phases can be reduced, which has the effect of improving stopping accuracy and reducing variations in damping characteristics.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of an embodiment of the present invention, Fig. 2 is a pulse waveform diagram applied to the excitation coil, Figs. 3 and 4 are explanatory diagrams of the conventional example, and Fig. 5 is an explanatory diagram of the excitation coil. FIG. 6 is a diagram of a unipolar drive circuit that drives the excitation coil, and FIG. 6 is a diagram of a bipolar drive circuit that drives the excitation coil. l... Stator teeth, 2... Stator, 3-6... Slider teeth, 7.8... Movable tooth portion, 9... Permanent magnet,
10-13... Exciting coil procedural amendment (self-government January 17, 1985 Patent Application No. 213872 2, name of invention Linear pulse motor 3, person making the amendment Relationship with Hanyu Applicant 4, Agent 5, date of amendment order voluntary amendment 6, subject of amendment 7≦
8, j (The statement of claims in Specification 11 is amended as shown in the attached sheet. (2) On page 4, line 17 of the specification, "direction excitation" is corrected to "direction excitation J. 2. Claims: A stator having stator teeth arranged in one direction, and a pair of slider teeth facing the stator teeth and arranged in the direction in which the stator teeth are arranged, each having a pair of slider teeth arranged in the direction in which the stator teeth are arranged. a pair of movable tooth portions disposed in the movable tooth portion; a permanent magnet interposed between the movable tooth portions to polarize the movable tooth portions to mutually different magnetic poles;
a pair of excitation coils arranged between the slider teeth of each of the movable tooth parts to excite the slider teeth and having different numbers of turns, the slider teeth of each of the movable tooth parts far from the permanent magnet and the permanent magnet; The turn ratio of the excitation coil is set so that the magnetic flux of the permanent magnet and the magnetic flux of at least one of the excitation coils excited in the same direction are approximately equal to each other at the slider teeth close to the slider teeth. Features a linear pulse motor.

Claims (1)

[Claims] A pair of movable stators arranged in the direction in which the stator teeth are arranged, each having a stator with stator teeth arranged in one direction, and a pair of slider teeth facing the stator teeth and arranged in the direction in which the stator teeth are arranged. a permanent magnet that is interposed between the movable tooth portion and polarizes the movable tooth portion to have different magnetic poles;
a pair of excitation coils arranged between the slider teeth of each of the movable tooth parts to excite the slider teeth and having different numbers of turns, the slider teeth of each of the movable tooth parts far from the permanent magnet and the permanent magnet; The turn ratio of the excitation coil is set so that the magnetic flux of the permanent magnet and the magnetic flux of at least one of the excitation coils excited in the same direction as the magnetic flux of the permanent magnet are approximately equal to each other. Features a linear pulse motor.