JPS6323557A - Movable element-locking mechanism for linear pulse motor - Google Patents

Abstract

PURPOSE:To prevent displacement of a movable element in the non-excited state by providing a means which is operated in the non-excited state to give a locking force to a secondary side magnetic circuit of the movable element. CONSTITUTION:If a coil 61 is excited, a magnetic flux is saturated at a notch 64-forming portion of a coupled magnetic path 63 and a high permeability magnetic body 66 is attracted to the notch 64-forming portion. Consequently, a biasing member 65 is attracted toward the coupled magnetic path 63 and a locking-force imparting member 69 is shunted from the movable element 51, which is then operated smoothly. On the other hand, the biasing member 65 is energized by a flat spring 67 via the magnetic body 66 when the coil 61 is not exited and the locking-force imparting member 69 is pressed against a secondary side magnetic circuit (teeth forming portion 55) of the movable element 51. Therefore, a sufficient locking force is imparted to the movable element 51, which is prevented from being displaced.

Description

[Detailed Description of the Invention] [Summary] The present invention aims to prevent displacement of a mover during non-excitation in a linear pulse motor.
This objective is achieved by providing means for applying a loss force to the secondary side magnetic circuit of the movable element by operating in a de-energized state.

[Industrial application field]

The present invention relates to a linear pulse motor used for moving the head of a floppy disk drive, a carriage of a printer, etc., and particularly relates to a movable element locking mechanism that can prevent displacement of the movable element when not energized.

This type of linear pulse motor incorporates a stator magnetic circuit (primary side magnetic circuit) into a non-magnetic frame plate, and also has a guide mechanism between the stator and mover that guides the reciprocating linear movement of the mover. It is set up and configured.

[Conventional technology]

An example of a conventional linear pulse motor is shown in FIG. This linear pulse motor has low power consumption.

The present applicant has already filed an application (Japanese Patent Application Laid-Open No. 60-55852) for the purpose of miniaturization. In the figure, 1 is a mover and 2 is a stator. In addition, in FIG. 4, the gap holding 1 linear guide mechanism is omitted. The movable element 1 is provided with a large number of teeth 3 extending in the X direction and equally spaced at a pitch t in the Y direction perpendicular to the X direction.

The stator 2 includes magnetic poles 4.5, 6.7, a coil 8, and a permanent magnet 9. On the surface of each magnetic pole 4, 5, 6, 7 facing the movable element 1, teeth 10 that can face the teeth 3 are provided with a pitch of t.
The teeth 10 of the magnetic poles 4, 5.6 are formed at t/2°t/4, 3t/4, respectively, with respect to the teeth 10 of the magnetic pole 7.
only the phase is shifted. In the linear pulse motor having such a configuration, the movable element 1 makes a reciprocating rectilinear movement in the Y direction at a step amount of t/4 per pulse.

The applicant has proposed Article 6.7 as an application of this principle.
The linear pulse motor shown in the figure has already been proposed (patent application 1986-
No. 171617, filed on August 3, 1985).

This linear pulse motor is suitable for short-stroke applications such as head feeding of a Fronbi disk, and in the figure, 21 is a movable element, 22 is a stator, and 23 is a guide mechanism.

The stator 22 has magnetic poles 24.25, 26.27 and a coil 2.
8 and a permanent magnet 29 is supported by a non-magnetic frame plate 31,
Each of the magnetic poles 24, 25, 26° 27 is provided with teeth 32 opposing the teeth (not shown) of the movable element 21. This stator 22
is manufactured by the following steps. That is, first, the stator magnetic circuit 30 is fixed to the frame plate 31 with adhesive, mold, etc., and then gear cutting is performed using the surface 33 of the frame plate 31 (the part where the rope lines are drawn in Fig. 6) as a reference. form 32. 34 and 35 are a linear guide board and a linear guide spring plate fixed to the frame plate 31, respectively; 36
is a mounting section integrally formed on the frame plate 31, and the mounting section 36 is provided with a hole 37.

The guide mechanism 23 includes a gap holding rolling element 38, a linear guide rolling element 39, and a retainer 40 that holds these rolling elements.

The rolling element 3 is sandwiched between the lower surface (raceway surface) 21a of the mover 21 and the surface (raceway surface) 33 of the frame plate, and as a result,
A gear is held between the teeth of the movable element 21 and the teeth 32 of each magnetic pole portion of the stator 22.

Further, the rolling elements 39 are connected to both sides of the movable element 21 and to the linear guide substrate 34. It is sandwiched between linear guide spring plates 35.

When the linear pulse motor having such a configuration is operated, the movable element 21 is guided by the displacement of the rolling elements 38 and 39, and moves in a reciprocating direction in a direction perpendicular to the plane of the drawing of FIG. Since this linear pulse motor has a short stroke, a guide mechanism using rolling elements can be applied, and this guide mechanism is inexpensive and has a long life.

Note that the head is mounted on the movable element.

[Problem that the invention seeks to solve]

As mentioned above, the guide mechanism of the linear pulse motor shown in Fig. 6.7 maintains a gap using rolling elements.

It provides linear guidance and has low frictional force. child
When a linear pulse motor like this is incorporated into a floppy disk drive and transported with the power turned off, the mover will be displaced when subjected to external force or excitation force.
The impact may damage the linear pulse motor or floppy disk drive.

As a countermeasure to this problem, it may be possible to use a mover displacement mechanism using sliding friction instead of rolling elements, but in this case,
There is a problem in that it is difficult to maintain stable frictional force and suppress wear, and moreover, the power efficiency during displacement of the mover due to coil excitation is reduced due to frictional force.

[Means for solving problems]

The present invention provides a mover locking mechanism for a linear pulse motor that can solve the above-mentioned problems. A pressing member and an elastic member are provided.

The pressing member is provided so as to be movable between the mover and a coupling magnetic path that magnetically couples a plurality of magnetic poles of each phase arranged so that the flow of the bias magnetic path by the permanent magnet is the same, The magnetic body is integrally provided on the coupling magnetic path side of this pressing member.

The elastic member is disposed between the magnetic body and the coupling magnetic path, and urges the pressing member toward the movable element.

[Effect]

When the coil is excited, the magnetic body with high magnetic permeability receives an attractive force from the coupling magnetic path, causes the elastic member to elastically deform, and is attracted to the coupling magnetic path (because the magnetic attraction force is set larger than the spring force of the elastic member) ).

When the coil is excited, the magnetic attractive force acting on the magnetic material becomes very small (only a magnetic flux equal to the difference between the bias magnetic fluxes flowing through the magnetic poles on both sides flows in the coupling magnetic path, but this magnetic flux is small compared to the magnetic flux caused by coil excitation). Therefore, the pressing member is biased by the elastic member through the magnetic material and presses against the movable element. Therefore, a locking force is applied to the movable element, and displacement of the movable element is prevented.

〔Example〕

The present invention will now be described in detail with reference to FIGS. 1 to 4.

A first embodiment is shown in FIGS. 1 to 3.

FIG. 1 is a front view showing the main parts of a linear pulse motor to which the present invention is applied. In the figure, 51 is a mover, 52 is a stator, and 5
3 is a movable element locking mechanism.

The movable element 51 is configured by providing a large number of teeth 55 on the lower surface of a substrate 54. The teeth 55 extend perpendicularly to the plane of the drawing and are arranged at equal intervals in the horizontal direction of the drawing.

The stator 52 has two-phase magnetic poles 56, 57, 58° 59,
It is constructed by incorporating a permanent magnet 60 and a coil 61 for excitation of each phase magnetic pole into a frame (not shown). magnetic pole 58
．． 57 is a permanent magnet 6 on the back side of the magnetic pole 56 and 59 of the illustrated phase.
Located through 0. The magnetic poles of each phase each have teeth 62
are arranged so that the bias magnetic fluxes of the permanent magnets 60 flow in the same direction, and are magnetically coupled by a coupling magnetic path 63. The coupling magnetic path 63 is exposed at the center of the coil 61 and has a ■-shaped notch 64 on the movable element 51 side.

The movable element locking mechanism 53 includes a pressing member 65, a magnetic body 66 with high magnetic permeability, and a leaf spring (elastic member) 67. The pressing member 65 is movable up and down between the movable element 51 and the coupling magnetic path 63 using the side surfaces 68 of the legs of the magnetic poles as guides, and its upper surface is made of a material such as urethane sponge that is deformable and has a large coefficient of friction. The formed locking force applying member 69 is adhered. The magnetic body 66 is wedge-shaped and is integrally connected to the lower part of the pressing member 65 and facing the notch 64, but if the pressing member 65 is made of synthetic resin, it is insert molded therein and integrally formed with the magnetic body 66. can be converted into The leaf spring 67 is disposed between the notch 64 forming portion of the coupling magnetic path 63 and the magnetic body 66 .

Although not shown in the drawings, this linear pulse motor has a guide mechanism similar to that shown in Fig. 6.7, which includes a gap holding rolling element, a linear guide rolling element, and a retainer that holds these rolling elements. It is provided for guiding the movable element 51.

The structure of the present invention is as described above, and the operation will be explained next.

When the coil 61 is excited, the notch 6 of the coupling magnetic path 63
The magnetic flux is saturated at the portion where the coupling magnetic path 63 is formed, and the high permeability magnetic body 16 is attracted to the portion where the notch 64 is formed.

In this case, the magnetic attraction force is greater than the spring force of the leaf spring 67, the pressing member 65 is attracted to the coupling magnetic path side, and the locking force applying member 69 is retracted from the movable element 51. Therefore, this locking force applying member 69 does not apply locking force to the movable element 51,
The mover operates smoothly.

When the coil 61 is not energized, only a magnetic flux equal to the difference between the bias magnetic flux formed by the permanent magnet 60 and flowing through the magnetic poles on both sides flows through the coupling magnetic path 63, but this magnetic flux is small compared to the magnetic flux due to coil excitation. Therefore, the magnetic attraction force acting on the magnetic body becomes very small, and the pressing member 65 is biased by the plate spring 67 via the magnetic body 66, and the locking force applying member 69 is applied to the secondary side magnetic circuit (tooth 55 forming part). Therefore, a sufficient force is applied to the movable element 51 by the locking force applying member 69 having a large coefficient of friction, and displacement of the movable element 51 is prevented.

When switching the excitation direction of the coil 61, the attraction force of the magnetic body 66 by the coil 61 decreases for a short time (determined by the electrical time constant of the coil). Therefore, as shown in FIG. 2, each phase is integrated to form a pressing member 65, and the linear pulse motor is used in a two-phase excitation system. However, the magnetic body 66 is not integrated, but is magnetically separated for each phase. This is to prevent the flow between the phases flowing through the coupling magnetic path of each phase.

FIG. 3 shows another excitation coil of the locking force applying member provided on the upper surface of the pressing member. In this case, a plurality of teeth 70 formed with equal pinches on the upper surface of the pressing member 65 constitute a locking member. This tooth 70 corresponds to the tooth 5 of the movable element 51.
5 and the same pitch t, and extend in the same direction as the teeth 55. In this case, the teeth 70 fit into the grooves of the teeth 55 when the coil is de-energized to produce a locking effect, so that displacement of the movable element 51 can be prevented.

FIG. 4 shows a second embodiment.

FIG. 4 is a front view showing the main parts of the linear pulse motor, in which 81 is a stator and 82 is a movable locking mechanism. The mover 51 is similar to the previous example.

In the stator 81, the coupling magnetic path 83 is not provided with a notch, and the coil 84 is provided with each magnetic pole 56 (58), 59 (57
) is the same as the previous example except that it is wrapped around the tooth preparation part.

The movable element locking mechanism 82 is composed of a pressing member 85, a magnetic body 86 with high magnetic permeability, and a wavy spring (elastic member) 87.

In the case of this example, no notch is formed in the coupling magnetic path 83, and the coil 84 is located in a portion other than the coupling magnetic path 83 (
The coupling magnetic path 83 is wound around the tooth forming part of each magnetic pole.
Since the excitation magnetic flux of the coil 84 is saturated over almost the entire length of the magnetic body 86, the magnetic body 86 is attracted to the coupling magnetic path 83.

In this case, the attracting surface of the magnetic body 86 can be widened,
Moreover, most of the excitation magnetic flux of the coil passes through the gap, so there is little magnetic flux leakage. When the coil is de-energized, the pressing member 8
5 is biased by a leaf spring 87 and moves upward, and a locking force imparting member 88 such as urethane sponge bonded to the upper surface of the pressing member 85 is applied to the secondary side magnetic circuit (tooth forming portion) of the movable element 51. The movable element 51 is locked by pressure contact.

Above is the first part. Although the second embodiment has been described, the present invention is not limited to a linear pulse motor using rolling elements as shown in FIG. It is also applicable to a long stroke linear pulse motor configured to guide a movable element using the bearing.

〔Effect of the invention〕

As described above, according to the present invention, when the movable element is displaced by coil excitation, the pressing member is not in contact with the secondary magnetic circuit of the movable element, and the movable element can be smoothly displaced without being hindered. When the coil is activated and the coil is not energized, the pressure contact member is energized by the elastic member and is pressed against the secondary magnetic circuit to reliably lock the displacement of the movable element. Further, the thrust generating coil of the linear pulse motor also serves as a coil for attracting the pressing member to the coupling magnetic path. Therefore, a movable locking mechanism with a long life, high power efficiency, and a small number of parts can be obtained.

[Brief explanation of drawings]

FIG. 1 is a front view showing the main parts of the linear pulse motor according to the first embodiment of the present invention, FIG. 2 is a perspective view showing details of the pressing member, and FIG. 3 is another example of the pressing member. FIG. 4 is a front view showing essential parts of a linear pulse motor according to a second embodiment of the present invention, FIG. 5 is a perspective view showing an outline of a conventional linear pulse motor, and FIG. 6 is a conventional linear pulse motor. 7 is an exploded perspective view showing another linear pulse motor. FIG. 7 is a side view showing an assembled state of the linear pulse motor shown in FIG. 6. In the figure, 5I is a mover, 51.81 is a stator, and 53.82 is a Mover locking mechanism, 56.57, 58.59 are magnetic poles, 60 is a permanent magnet, 61.84 is a coil, 63.83 is a coupling magnetic path, 64 is a notch, 65.85 is a pressing member, 66.86 is a A magnetic material with high magnetic permeability, 67.87 is a plate spring (elastic member), and 69.88 is a locking force applying unit.

Claims (1)

[Claims] On a stator (52) equipped with a primary magnetic circuit consisting of a permanent magnet (60), an excitation coil (61), and multi-phase magnetic poles (56, 57, 58, 59), A movable element (51) equipped with a next-side magnetic circuit is supported for reciprocating linear movement, and the plurality of magnetic poles (56, 57, 58, 59) of each phase are
In a linear pulse motor arranged so that the bias magnetic path by the permanent magnet (60) has the same flow and is magnetically coupled by a coupling magnetic path, the secondary side magnetic circuit of the movable element and the coupling magnetic path A pressing member (65) is provided that is movable between the pressing member (65).
A magnetic body (66) with high magnetic permeability that is attracted to the coupling magnetic path when the coil is energized is integrally provided on the coupling magnetic path (63) side of the coil, and the magnetic body (66) and the coupling magnetic path (63) is provided with an elastic member (67) that activates the pressing member (65) and presses it against the secondary magnetic circuit of the movable element when the coil (61) is not energized. Features a linear pulse motor mover locking mechanism.