JPH08280155A - Motor with lead screw - Google Patents

Abstract

PURPOSE: To provide a motor with a lead screw which can secure the stability of a pressurizing mechanism by setting the deformation of an energizing member at a larger value and can be constituted as short as possible in the axial direction. CONSTITUTION: In order to eliminate the backlash of a motor with a lead screw in the axial direction, the motor is rotatably supported in a state where one end is not movable in the axial direction and the other end is energized in the axial direction and, at the same time, a lead screw having a feed screw groove section 5a is formed on the output shaft of the motor. On the other end side of the motor, the output shaft is inserted into a bottomed hole section 5c successively to an energizing member 9 so that the bottom face of the shaft can be protruded from the member 9 by a prescribed amount while the bottom face is brought into contact with the member 9. Therefore, the motor is provided with a bar-like member 10 having a spherical surface 10a and nearly flat lid member 11 which is brought into contact with and pushes the spherical surface 10a and is fixed to a base section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor with a lead screw, for example, a lead screw which can be shortened in the axial direction when used as a drive for tracking a recording or reproducing head with respect to a disk-shaped recording medium. It is related to an attached motor.

2. Description of the Related Art Conventionally, in a magnetic disk device or the like, a lead screw which is a feed screw is formed on an output shaft of a stepping motor, and a desired head is mounted on a carriage which engages with the lead screw. 2. Description of the Related Art A magnetic disk device is known in which a head is accessed to a desired track on a disk by driving a stepping motor in a predetermined manner based on a command signal. In such a device, it is essential that the amount of rotation of the stepping motor is accurately converted into the parallel movement of the carriage without error in the rotation-linear motion conversion by reducing the play in the axial direction of the lead screw to zero. Is.

Therefore, it has been conventionally practiced to provide a preload mechanism for preventing the lead screw from moving in the axial direction at least in a normal operation state where an excessive load is not applied. Specifically, one end of the motor rotating shaft is rotatably supported by a pivot bearing so that the one end of the motor rotating shaft is rotatably supported, while the other end of the motor rotating shaft is provided with a spring arm of a predetermined length configured to support substantially one piece. In many cases, a leaf spring was used to urge the blade in the axial direction.

The preload mechanism using a leaf spring having such a structure has an advantage that its structure can be simplified. However, a desired biasing force can be obtained by bending the spring arm of the leaf spring in the longitudinal direction of the lead screw in a single-supported state. Since the variation of the axial length of the lead screw affects the biasing force of the preload mechanism, there is a problem that the preload accuracy cannot be sufficiently guaranteed.

Further, depending on the variation in the total length of the lead screw in the axial direction, the spring arm comes into contact with the lead screw in a state of being inclined with respect to the axial end of the lead screw. When contact is made, a component force in the radial direction is generated and a rather harmful biasing force is generated in the preload mechanism, which may cause uneven wear of the relevant portion. In particular, when the leaf spring is constructed in a small size, it is more difficult to prevent the contact of the spring arm with the shaft end when the spring arm is tilted as described above, because the spring arm length cannot be taken sufficiently. Becomes

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 6-133490, there has been proposed one having an urging member that is movable in parallel by having a plurality of spiral slits instead of a leaf spring. Briefly describing the configuration of the above publication with reference to the drawings, FIG. 4A is a cross-sectional view of a main part of the publication, and FIG. 4B is a front view of a biasing member. In FIG. 4A, the lead screw 105 is the base 1
01 is rotatably supported by a bearing 103, the end of which is pivotally supported by a pivot bearing (not shown), and the end of the figure is axially supported by a biasing force generated when the biasing member 111 is deformed. It is urged to move to eliminate axial play. Further, a permanent magnet 107 made of a predetermined magnetic material and rotatably provided in a coil 108 fixed to the base 101 via a mounting plate 106 is fixed to the lead screw 105.
By generating a rotating magnetic field at 08, the lead screw 105 is rotated by a predetermined amount.

Further, the biasing member 111 has a plurality of spiral slits 111b as shown in FIG. 4 (b) so that the working portion 111a can be moved in parallel, and a biasing force acts on the end portion. On the other hand, as shown in FIG. 4A, a lid member 112 is provided to prevent the biasing member 111 from being deformed more than the maximum amount. According to the above configuration, it is possible to prevent the situation in which the spring arm of the leaf spring is in contact with the shaft end of the lead screw in a tilted state, so that a component force in the radial direction is not generated, which is harmful. It is possible to prevent uneven wear and the like by eliminating the generation of power.

[0007]

However, in the structure shown in FIG. 4, in order to absorb the variation in the axial length of the lead screw, the biasing member 1 is used.
It is necessary to allow the action portion 111a to move in parallel with a sufficient stroke by setting the length of the spiral slit 111b of 11 large. In other words, the stability of the preload mechanism can be achieved by setting the deformation amount of the biasing member to be larger.

However, according to the above proposal, the lid member 112 for deforming the urging member 111 excessively beyond the elastic limit when it receives a strong impact force due to a drop or the like during transportation or during use. Because it projects in the axial direction,
It is inevitably made longer in the axial direction.

Therefore, the present invention has been made in view of the above problems, and the stability of the preload mechanism can be sufficiently ensured by setting the deformation amount of the biasing member to be larger. An object of the present invention is to provide a motor with a lead screw that can be configured to be as short as possible in the axial direction.

In addition to the above object, it is another object of the present invention to provide a motor with a lead screw capable of ensuring an initial operating state for a long time.

[0011]

In order to solve the above-mentioned problems and to achieve the object, the present invention has one end rotatably supported in an axially immovable state in order to eliminate axial play.
A motor with a lead screw in which the other end is rotatably supported in an axially biased state, and a lead screw having a feed screw groove portion is provided on the output shaft, and the other end is concentrically drilled. A bottomed hole portion, a biasing member that is inserted into the bottomed hole portion, and a biasing member that is inserted subsequent to the biasing member, the bottom surface of which is in contact with the biasing member. A rod-shaped member that protrudes from the end by a predetermined amount and that has a spherical surface formed on the surface facing the bottom surface, and a substantially flat lid member that is fixed to the base portion that is in contact with the spherical surface and is in the biased state. It is characterized by having and.

Further, the rod-shaped member is characterized in that a grease-like lubricant is applied to a pressure contact portion between the spherical surface and the lid member by the urging force of the urging member.

Further, one end is rotatably supported by a pivot bearing, and the other end is rotatably supported in an axially biased state so as to eliminate axial play and to feed screw starting from the one end. A motor with a lead screw in which a lead screw having a groove formed on an outer peripheral surface is integrally provided on a motor output shaft, wherein a bottomed hole portion concentrically formed at the other end of the motor output shaft, A compression coil spring that is inserted into the bottomed hole portion, and is inserted subsequently to the compression coil spring, the bottom surface of the compression coil spring abuts against the compression coil spring, and a predetermined amount is projected from the other end. A rod-shaped member having a conical surface or a predetermined spherical surface formed on opposite surfaces, and a coil end of the motor for abutting against the conical surface or the predetermined spherical surface to bring the coil into the biased state. Substantially a flat cover member which is fixed, is characterized by comprising a grease-like lubricant is applied to the pressure contact portion of the lid member.

Further, the motor with the lead screw is provided with an engaging portion which engages with the feed screw groove portion in order to use the recording or reproducing head for tracking drive of a predetermined disk-shaped recording medium, It is characterized in that it comprises a carriage that is arranged so as to be movable parallel to the motor output shaft and that carries the recording or reproducing head.

Further, the rod-shaped member is provided with a detent shape portion for deterring rotation in the bottomed hole portion.

[0016]

In the above structure, one end is rotatably supported in the axially immovable state and the other end is rotatably supported in the axially biased state, and the lead screw having the feed screw groove is formed. In order to provide the output shaft on the output shaft, a bottomed hole is concentrically formed, a biasing member is inserted into the bottomed hole, and a spherical surface is formed on the surface of the biasing member. After inserting and projecting a predetermined amount, a substantially flat lid member that abuts the spherical surface can be fixed to the base to shorten the axial direction, and the stroke of the biasing member can be made sufficient to stabilize the preload mechanism. It works to secure the property and eliminate the looseness in the axial direction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing a main part of a motor with lead screw of the embodiment in a broken manner.

In the figure, the motor with lead screw is mounted on the carriage 20 with respect to a disc-shaped predetermined recording medium (not shown) by moving the carriage 20 shown by the broken line in the figure along the shaft body 21. The present invention is not limited to this, and is used for using a recording or reproducing head for driving a recording or reproducing head as described above. It is particularly applicable in some cases.

In order to configure the rotation-linear motion conversion mechanism as described above, the carriage 20 is provided with an engaging portion which engages with the feed screw groove portion 5a formed on the outer peripheral surface of the lead screw 5 without play. 20a is provided. Further, the shaft body 21 is arranged in parallel with the lead screw 5 which is integrally formed with the motor output shaft.
A recording or reproducing head (not shown) is mounted on the position 0.

On the other hand, the base 1 has a left wall portion 1a as shown in the drawing.
And the right wall portion 1b are integrally formed into a substantially U-shape, and the first through hole portion 1c and the second through hole portion 1d are coaxially formed in the left wall portion 1a and the right wall portion 1b, respectively. It is set up. A pivot bearing 2 is press-fitted and held in the first through hole portion 1c, and a ball guide portion bored from the left end portion of the lead screw 5 makes point contact with a ball 4 rotatably incorporated therein. In this state, it can rotate with almost no load. In addition, a bearing 3 made of a sintered body or the like is provided in the second through hole 1d so as to sneak into the hole of the mounting member 6, and supports the lead screw 5 on the motor side.

Further, a permanent magnet 7 made of a predetermined magnetic material (including a resin magnet) is rotatably provided inside a coil 8 fixed to the base 1 via a mounting plate 6, and is fixed to the lead screw 5. By generating a rotating magnetic field in the coil 8, the lead screw 5
Is rotated by a predetermined amount to move the carriage 20 in an arbitrary direction.

The lead screw 5 has a configuration example in which the lead screw having the feed screw groove portion 5a formed on the outer peripheral surface is integrally provided on the motor output shaft. You may make it join from the middle.

Next, the right end 5d of the lead screw 5
Has a bottomed hole 5c having a depth of more than half of the total length of the permanent magnet 7, and the free length is set to 1.5 to 2 times as shown in the drawing. A built-in compression coil spring 9 having a predetermined wire diameter, a predetermined number of turns, and a predetermined outer dimension is inserted into the compression coil spring 9 so that the bottom surface of the compression coil spring abuts and a predetermined amount projects from the right end 5d. The rod-shaped member 10 is inserted so as to be movable in the longitudinal direction.

The surface of the rod member 10 forms a spherical surface 10a as shown in the drawing, and a substantially flat lid member 11 fixed to the side surface of the bobbin by spot welding or the like is brought into contact with the bobbin. Before the surface 11a is completed so as to abut against the spherical surface 10a, the abutment surface 1 of the lid member 11 is previously formed.
A grease-like lubricant is applied to 1a.

By completing the process as described above, the overall length L of the lead screw along the axial direction can be shortened, and the stroke of the compression coil spring 9 provided in the bottomed hole 5c having a sufficient depth dimension can be sufficiently provided. Thus, the stability of the preload mechanism can be secured.

FIG. 2 is a cross-sectional view of essential parts showing a comparison between the motor with a lead screw having the structure of FIG. 1 and the motor with a lead screw described in the above publication. In this figure, for comparison, coils 8 and 108 and permanent magnets 7 and 1 are shown.
07 has the same shape and the same dimensional relationship. First, in the case of the above-mentioned embodiment, since the lid member 11 is a flat plate fixed to the side surface of the coil 8, it is elongated in the axial direction by the thickness of the plate. Further, the deformation stroke X for preloading the compression coil spring 9 can be sufficiently secured. And the right shaft end 5d
It is possible to sufficiently secure the distance A from the contact surface 11a of the lid member 11 to the contact surface 11a.

On the other hand, in the conventional case, first, in order to secure the stroke X for the parallel movement of the acting portion of the biasing member 111, the cover member 112 has a plate thickness t with respect to the side surface of the coil 108. In addition, the distance A from the biasing member 111 to the inner surface of the lid member 112 is provided in order to avoid interference due to variations in the total length of the parts, so that it becomes longer in the axial direction.

As described above, according to the structure of this embodiment, the deformation stroke X for preloading the compression coil spring 9 as the biasing member can be sufficiently secured, and the axial length can be sufficiently shortened. Since a compression coil spring whose compression force is relatively easy to manage is used instead of the leaf spring, it is suitable for a motor with a lead screw having an outer diameter of 10 mm or less, for example.

Finally, FIGS. 3 (a) to 3 (c) are front views showing the rotation preventing structure of the rod-shaped member 10, and FIGS.
(F) is a cross-sectional view of the rod-shaped member 10. In the embodiment described above, the rod-shaped member 10 inserted into the bottomed hole portion 5c formed in the right end portion 5d of the lead screw 5 is movable in the depth direction of the bottomed hole portion 5c. Is stated.

However, in consideration of, for example, a large biasing force of the compression coil spring or a situation in which a foreign substance enters the bottomed hole 5c, the rod member 10 should never rotate in the bottomed hole 5c. You may actively deal with it.

Therefore, the rod-shaped member 10 is shown in FIGS.
From the combination of the surface portion 10a shown in (c), which is a spherical or conical or hemispherical shaped portion having a predetermined radius, and the cross-sectional shape of the rod-shaped member 10 shown in FIGS. After processing the bar-shaped member 10 configured as described above, (d) to
By inserting the rod-shaped member 10 into the bottomed hole 5c, which is a female hole matching the outer shapes 10b and 10d shown in (f), the rod-shaped member 10 can always rotate integrally with the lead screw 5. It becomes possible to rotate in a constantly biased state.

The present invention is not limited to the above-mentioned embodiment, and various constructions are possible. For example, a pivot bearing may be replaced by a thrust bearing or a shaft end may be inserted into a simple hole. It is also possible to provide the pivot bearing on the motor installation side. Further, it goes without saying that the motor is not limited to the above step motor, but may be a DC motor or any type thereof.

[0032]

As described above, according to the present invention, by setting the deformation amount of the biasing member to be larger, the stability of the preload mechanism can be sufficiently ensured and the axial direction can be made as short as possible. A motor with a lead screw can be provided.

Further, it is possible to provide a motor with a lead screw capable of ensuring an initial operating state for a long time.

[0034]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part showing a main part of a motor with a lead screw according to an embodiment.

FIG. 2 is a cross-sectional view of essential parts showing a comparison between the motor with a lead screw of the embodiment of FIG. 1 and a conventional motor with a lead screw.

3A to 3C are front views of the rod-shaped member 10,
(D)-(f) is a cross-sectional view of the rod-shaped member 10.

4A is a cross-sectional view of a main part showing a main part of a conventional motor with a lead screw, and FIG. 4B is a front view of a biasing member 111.

[Explanation of symbols]

 1 base 2 pivot bearing 3 bearing 5 lead screw 6 mounting plate 7 permanent magnet 8 coil 9 compression coil spring (biasing means) 10 rod member 11 lid member 20 carriage

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yukinori Arai 2-16-20 Shimura, Itabashi-ku, Tokyo Inside Copal Co., Ltd.

Claims (5)

[Claims] 1. A feed screw, which has one end rotatably supported in an axially stationary state and the other end rotatably in an axially biased state in order to eliminate axial play. A lead screw motor in which a lead screw having a groove is provided on an output shaft, the bottomed hole being concentrically formed at the other end, and a biasing force inserted into the bottomed hole. And a rod-like member that is inserted following the urging member, the bottom surface of the urging member contacts the urging member and protrudes from the other end by a predetermined amount, and a spherical surface is formed on the surface facing the bottom surface. A motor with a lead screw, comprising: a member; and a substantially flat lid member that is fixed to a base portion that comes into contact with the spherical surface and is in the biased state. 2. The lead screw according to claim 1, wherein the rod-shaped member is coated with a grease-like lubricant at a pressure contact portion between the spherical surface and the lid member by the urging force of the urging member. With motor. 3. A feed screw starting from the one end while rotatably supported at one end by a pivot bearing and rotatably supported at the other end in an axially biased state so as to eliminate backlash in the axial direction. A motor with a lead screw in which a lead screw having a groove formed on the outer peripheral surface is integrally provided on a motor output shaft, the bottomed hole portion being concentrically formed at the other end of the motor output shaft, A compression coil spring to be inserted into the bottomed hole portion, the compression coil spring being inserted subsequently to the compression coil spring, the bottom surface of the compression coil spring comes into contact with the compression coil spring, and a predetermined amount is projected from the other end. A rod-shaped member having a conical surface or a predetermined spherical surface formed on the opposite surfaces, and a coil member of the motor for abutting against the conical surface or the predetermined spherical surface to establish the biasing state Substantially a flat lid member being worn, the lead screw with the motor, characterized by comprising, a grease-like lubricant is applied to the pressure contact portion of the lid member. 4. The motor with a lead screw is provided with an engaging portion that engages with the feed screw groove portion in order to use a recording or reproducing head for tracking drive on a disc-shaped recording medium,
The motor with a lead screw according to claim 3, further comprising a carriage that is movably arranged in parallel with the motor output shaft and that carries the recording or reproducing head. 5. The motor with lead screw according to claim 1, wherein the rod-shaped member includes a detent shape portion that detents the detent hole in the bottomed hole portion.