JPH02218072A - Bearing mechanism of magnetic head driving motor for magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To make friction torque uniform by arranging bearings at both ends of a screw shaft, and providing a pivot bearing at one side and the bearing to support the shaft in its axial direction through a sphere at the other end, and providing a pre-loading spring to push the latter bearing to the axial direction. CONSTITUTION:The ball 4 is received in a hole part 3 at the tip end of the load screw shaft 1. The pivot bearing 5 is fitted and fixed to a hole 11 bored at a fitting frame 10 to support the shaft 1. Besides, the ball 13 is received in the hole part 9 bored at the other end of the shaft 1. The cylindrical head part 6a of the bearing 6 to support freely rotatably the other end of the shaft 1 is inserted and fitted to a cover member 2 attached to a stator 8b. The pre- loading spring 12 is installed between an annular leg part 6b and the member 2. The spring 12 regulates the shaft 1 in the axial direction through the sphere 13 as cooperating with the bearing 6. Thus, the shaft 1 is pre-loaded, and its play in the axial direction is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a bearing mechanism for a motor for driving a magnetic head of a magnetic recording ML device.

(Prior Art) As shown in FIGS. 2 and 3, a bearing mechanism for a magnetic head driving motor of a conventional magnetic recording device has an end portion on one rising surface 10a of a U-shaped mounting frame 10. A pivot bearing 5 is provided to support the load in the direction perpendicular to the axis of the lead screw shaft 1, which is equipped with a screw portion S at the end thereof and a motor drive portion M is attached to the other end thereof, and a groove formed at the end of the lead screw shaft L. A sphere 4 is disposed between the hole 3 and the pivot bearing 5. On the outside of the other 01 angle surface 10b of the mounting frame 10, there is a rotor magnet 7 disposed around the outer periphery of the lead screw shaft l, and a stator 8a housing a coil so as to face this magnet.
, 8b, etc., is provided. Further, on the outside of the stator 8b, another bearing 16 for supporting the load in the perpendicular direction of the lead screw shaft l is arranged coaxially with the pivot bearing 5. A cover portion 14 is provided on the outside of the bearing 16. Further, the other end of the lead screw shaft 1 is provided with a long hole 19 in the axial direction.
The coil spring 18 and the sphere 13 are housed in the housing. The coil spring 18 presses the sphere 13 toward the cover 14, so that the sphere makes point contact with the cover 14. The foregoing arrangement is housed within a base frame 20, as shown in FIG.

When the motor drive unit M operates and the lead screw shaft 1 rotates, the needle pin 26 of the grip spring 28 provided on the lower surface of the carriage 22 is displaced within the groove la of the lead screw shaft 1. The carriage 22 is supported by a guide bar 24 and moves along with the magnetic head 30 a predetermined distance in the direction of the arrow.

(Problems to be Solved by the Invention) In the bearing mechanism of the magnetic head drive motor of the conventional magnetic recording device, as shown in FIG. It includes a spherical body 13 housed in the elongated hole 19 and a coil spring 18 that presses the spherical body 13 toward the cover portion 14 and applies preload in the axial direction of the screw shaft 1. Since there is a gap between the elongated hole 19 and the sphere 13, an unbalanced force is generated on the coil spring 18, and as a result, the preload force applied to the screw shaft 1 by the coil spring 18 is
During the rotation of the carriage, the carriage acts in a direction deviated from the axial direction, causing variations in frictional torque, making it difficult to accurately drive and control the carriage.

Further, a coil spring 1 is inserted into the long hole 19 of the screw shaft 1.
8, the two spheres 13 are pushed out of the elongated hole 19 of the screw shaft by the coil spring 18, making it extremely difficult for the assembler.

The present invention aims to solve the above-mentioned problems.

(Means for Solving the Problem) In order to achieve the above object, the present invention provides the configuration described below. That is, in a magnetic head drive motor of a magnetic recording device having a configuration in which a ball or needle slides in a groove provided in a screw portion of a rotatable lead screw shaft to linearly displace a magnetic head.

A bearing mechanism is constructed in which a sphere is housed in a hole at one end of the lead screw shaft, and the sphere is in contact with a pivot bearing provided on the mounting frame, and a sphere is housed in a hole at the other end of the lead screw shaft. a sphere; a bearing whose head is fitted into a cover member attached to the stator so as to rotatably support the outer diameter portion of the other end of the lead screw shaft in contact with the sphere; and the bearing and the cover member. This is a bearing mechanism for a magnetic head driving motor of a magnetic recording device, having a bearing mechanism including a preload spring installed between the bearing mechanism.

(Function) According to the present invention, the motor drive section is activated by arranging the bearing mechanisms at both ends of the lead screw shaft and by arranging the preload spring for applying preload to the lead screw shaft on one bearing side. In the conventional example, the variation in friction torque caused by the elongated hole provided in the lead screw shaft, the gap between the spheres, and the uneven force caused by the coil spring is caused by the preload spring provided on one bearing side and the lead screw. Since it is absorbed by the sphere housed in the end hole of the shaft, it becomes easier to control the drive of the carriage by the rotation of the lead screw shaft. Further, unlike the conventional example, there is no problem such as the sphere being pushed out of the long hole of the lead screw shaft during assembly, which improves assembly workability.

(Example) An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view of a lead screw shaft according to the present invention.

The lead screw shaft 1 is divided into a screw part S and a driving part M equipped with a motor. First, let's talk about the screw part S in wSl. Lead screw shaft 1
A sphere 4 is housed in the tip hole 3 of. A pivot bearing 5 is fitted and fixed into a hole 11 drilled in one rising surface 10a of a mounting frame 10 that supports the lead screw shaft 1, and the sphere 4 and the pivot bearing 5 form one bearing mechanism of the lead screw shaft 1. form.

Also, a hole 9 bored at the other end of the lead screw shaft l.
The sphere 13 is stored in.

The cylindrical head 6a of the bearing 6, which rotatably supports the other end of the lead screw shaft l, is fitted into the cover member 2 attached to the stator 8b of the motor drive section M. A preload spring 12 is installed between the annular leg portion 6b of the shaft bearing 6 and the cover member 2. The preload spring 12 cooperates with the bearing 6 [.

Thus, the lead screw shaft 1 is restricted in the axial direction via the first sphere 13.

While the motor drive unit is in operation, the preload spring 12 and the sphere 13 absorb the variation in frictional torque described in the conventional example, thereby achieving smooth rotation of the lead screw shirt (1). That is, the preload spring 12 makes the lead screw shaft l freely displaceable in the axial direction through the bearing 6 via the sphere 13, thereby applying preload to the lead screw shaft 1 and eliminating play in the axial direction of the lead screw shaft l. useful for.

As is clear from the above explanation, the lead screw shaft of the present invention is provided with a bearing structure at both ends thereof,
This is to maintain good balance in the axial direction when the lead screw shaft rotates to ensure smooth rotation.

It should be noted that among the reference numerals used in the non-conventional examples, the same ones as those in the conventional example indicate the same members, so a detailed explanation thereof will be omitted.

(Effects of the Invention) As explained in detail above, according to the present invention, bearings are arranged at both ends of the screw shaft, and bipolar/
) A bearing is provided on the other side to support the outer diameter of the lead screw shaft in the axial direction via a sphere, and a preloading spring is further provided that allows the bearing to be freely displaced in the axial direction. This eliminates misalignment between the preload direction and the axial direction, and the friction torque becomes uniform, making it easier to control the rotation of the lead screw shaft. In addition, the bearing presses the sphere toward the hole due to the action of the preload spring, so that the sphere can be prevented from protruding during the lead screw shaft assembly process, and work efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a bearing mechanism of a motor according to an embodiment of the present invention. FIG. 2 is a sectional view of a conventional motor bearing mechanism. FIG. 3 is a cross-sectional view of a magnetic head drive device for each magnetic recording bag equipped with a motor bearing mechanism. ■... Lead screw shaft, 2... Cover member, 3... Hole, 4... Sphere, 5, 6... Bearing, 6
a... Cylindrical head, 6b... Annular leg, 9... Hole, 10... Frame, 10a, 10b... Rising surface, 11... Hole, 12... Preload spring, 13
... Sphere, 22... Carriage, 2B... Needle bin 30... Rii head, M... Motor drive section, S... Lead screw shaft screw section. Applicant Kobal Electronics Co., Ltd. Agent Patent Attorney Sakae Kobayashi

Claims (1)

[Claims] 1. Magnetism of a magnetic recording device having a configuration in which a magnetic head carriage is linearly displaced by a ball or needle sliding in a groove provided in a screw portion of a rotatable lead screw shaft. In a head drive motor, a ball is housed in a hole at one end of the lead screw shaft, and a bearing mechanism is configured such that the ball is in contact with a pivot bearing provided on the mounting frame, and a bearing mechanism is provided at the other end of the lead screw shaft. a sphere housed in the hole; a bearing whose head is fitted into a cover member attached to the stator so as to rotatably support the outer diameter portion of the other end of the lead screw shaft in contact with the sphere; A bearing mechanism for a magnetic head driving motor of a magnetic recording device, comprising a bearing mechanism including a preload spring installed between the bearing and a cover member. 2. A bearing mechanism for a magnetic head driving motor of a magnetic recording device according to claim 1, wherein a bearing is fitted and fixed in a hole provided in one rising portion of a mounting frame that supports a lead screw shaft. 3. A bearing mechanism for a magnetic head driving motor of a magnetic recording device according to claim 1, wherein a preloading spring is installed between the leg portion of the bearing and the cover member.