JP2665985B2 - Rotary drive - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor type rotary drive device which holds and rotates a member to be rotated such as a disk.

[Conventional technology]

For example, a spindle motor or the like is used as a device for holding and rotating a member to be rotated such as a disc.

This spindle motor type rotary drive device is, for example,
A spindle for holding a member to be rotated is rotatably supported on the fixed shaft, and a rotor of a magnetic material fixed to the spindle is driven to rotate by a face-to-face thin brushless motor.

In this type of motor for rotating a disk-shaped disk or the like, two bearings arranged at predetermined axial positions are usually used as bearings for supporting a rotating part (spindle) with respect to a fixed part. It is used.

As this bearing, a radial ball bearing having high rotation accuracy is usually used.

FIG. 2 is a longitudinal sectional view showing a conventional structure of the rotary drive device.

In FIG. 2, a spindle 1 is rotatably supported by a shaft 5 fixed (planted) on a magnetic chassis 4 via two radial ball bearings 3, 3 arranged in the axial direction. Have been.

That is, the two radial ball bearings 3, 3 have their outer rings fitted to the inner diameter of the spindle 1, and their inner rings fitted to the shaft 5.

Further, these radial ball bearings 3 are provided with caps 13.
Thereby, those inner rings are positioned and fixed to the shaft 5.

The spindle 1 is provided with a chucking magnet 2 for holding a rotated member 15 such as a disk.

A rotor yoke 9 made of a disk-shaped magnetic material is fixed to the spindle 1, and a rotor magnet 8 is attached to one surface of the rotor yoke 9.

The rotor magnet 8 forms a magnetic path with the chassis (opposite yoke) 4 of the magnetic material.

In a magnetic path between the rotor magnet 8 and the chassis 4, there is arranged a drive coil 10 connected to a substrate 11 by soldering or the like.

The board 11 is connected to a drive circuit (not shown) and a servo board.

[Technical problem to be solved by the invention]

However, in the above-mentioned conventional rotary drive device, there is a technical problem that the thickness (height) of the drive device becomes large because the two radial ball bearings 3, 3 are used while being arranged in the axial direction.

Further, in terms of cost, there is also a technical problem that it is difficult to reduce the cost of the entire drive device because a plurality of radial ball bearings 3, 3 which are considerably more expensive than other mechanical parts are used.

The present invention has been made in view of the above-mentioned conventional technical problems, and an object of the present invention is to easily adjust a magnetic path gap to easily increase driving efficiency, and to maintain high rotational accuracy. An object of the present invention is to provide a rotary drive device capable of reducing the thickness of the device and reducing the cost.

[Means for solving the problem]

In order to achieve the above object, the present invention rotatably supports a spindle on a shaft fixed to a chassis made of a magnetic material, and provides the rotor with a rotor yoke, a rotor magnet, and a member to be rotated. In a rotary drive device of a spindle motor type, which is provided with a drive coil facing the rotor magnet and energizes the drive coil to rotate a driven member held by the spindle, a bearing portion of the spindle is fitted to the shaft. A radial ball bearing to be combined with a thrust bearing provided on the tip end surface of the shaft, forming a female screw hole passing through the rotation axis of the cap portion of the spindle, and screwing a male screw member into the female screw hole, A thrust bearing is formed on a conical recess formed on a tip end surface of the shaft and on an inner end surface of the male screw member. A magnetic path gap formed between the rotor yoke and the chassis is adjusted by turning the male screw member to adjust the position of the spindle with respect to the chassis. It is characterized by the following.

〔Example〕

 Hereinafter, the present invention will be specifically described with reference to FIG.

FIG. 1 is a longitudinal sectional view of an embodiment of the rotary driving device according to the present invention.

In FIG. 1, a spindle 1 is rotatably supported on a shaft 5 fixed (planted) on a magnetic chassis 4 via one radial ball bearing 3 and one thrust ball bearing 6. Have been.

The radial ball bearing 3 has an outer ring fitted to the inner diameter of the spindle 1 and an inner ring fitted to the shaft 5.

The thrust ball bearing 6 is sandwiched between a conical recess 16 formed at the center of the end of the shaft 5 and a conical recess 18 provided in a cap 17 of the spindle 1.

The conical recess 18 on the spindle 1 side has the following structure.

That is, a female screw hole passing through the rotation axis of the cap portion 17 of the spindle 1 is formed, and the male screw member 12 is screwed into the female screw hole. The shaft 5 side end (the inner end face, The conical concave portion 18 is formed at the center of rotation of the lower end surface in the drawing).

The position of the conical recess 18 can be adjusted by rotating the male screw member 12 relative to the spindle 1 itself in the axial direction (vertical direction in the drawing) by rotating the male screw member 12 with a screwdriver or the like. Also, the relative position can be adjusted in the axial direction with respect to the spindle 1 itself.

Thus, the spindle 1 is supported via the thrust ball bearing 6 so that the axial position of the spindle 1 can be adjusted with respect to the shaft 5 fixed to the chassis 4.

Between the inner surface of the cap portion 17 of the spindle 1 and the outer ring of the radial ball bearing 3, a compression spring 7 for urging the outer ring with a predetermined spring force is mounted.

The spindle 1 is provided with a chucking magnet 2 for holding a rotated member 15 such as a disk.

A rotor yoke 9 made of a disk-shaped magnetic material is fixed to the spindle 1, and a rotor magnet 8 is attached to a side surface of the rotor yoke 9 by bonding or the like.

The rotor magnet 8 forms a magnetic path with the chassis (opposed yoke) 4 of the magnetic material.

In a magnetic path between the rotor magnet 8 and the chassis 4, there is arranged a drive coil 10 connected to a substrate 11 by soldering or the like.

The board 11 is connected to a drive circuit (not shown) and a servo board.

A part of the rotor magnet 8 is provided with an FG (frequency generator) magnetized area, and an FG pattern is formed at a position facing the substrate 11, and the rotational speed is detected by the FG magnetized area and the FG pattern. Means are configured.

The rotatable member 15 such as the disc is centered by the cylindrical boss 19 of the spindle 1, and is positioned and held on the receiver 20 by the attraction force of the chucking magnet 2.

With the above configuration, the rotating part of the motor (spindle 1
And the rotor magnet 8) are positioned in the thrust direction in a state where the thrust ball bearing 6 receives magnetic attraction acting on the chassis (opposed yoke) 4 and the rotor magnet 8, and at the same time, the radial ball bearing 3 and the thrust ball bearing 6 so as to be rotatable around the axis defined by the reference numeral 6.

At this time, the preload of the spring 7 is set to be smaller than the magnetic attraction force.

Further, the position of the rotating portion of the motor (such as the spindle 1 and the rotor magnet 8) can be adjusted in the axial direction with respect to the chassis (opposed yoke) 4 and the rotor magnet 8 by rotating the male screw member 12. it can. Therefore, by rotating the male screw member 12 from the outside, the distance between the rotor magnet 8 and the chassis 4, that is, the magnetic path gap can be adjusted.

After adjusting the gap, to prevent the screw from loosening,
The spindle 1 and the male screw member 12 are fixed by a method such as bonding.

According to the embodiment described above, the bearing structure for rotatably supporting the spindle 1 holding the member to be rotated 15 such as a disk-shaped disk is composed of one radial ball bearing 3 and one thrust ball bearing 6. , The thickness of the device can be easily reduced as compared with the conventional bearing structure using two radial ball bearings 3, 3, and the cost of the bearing portion can be reduced. A rotary drive was obtained.

By turning the male screw member 12, the spindle 1
The rotor yoke 9 and the rotor magnet 8 can be moved up and down through the
The gap (magnetic path gap) between the motor and the chassis (opposed yoke) 4 or the drive coil 10 can be easily and accurately adjusted, and the driving efficiency of the rotary drive device can be stably maintained at a high level. Was.

〔The invention's effect〕

As apparent from the above description, according to the present invention, a spindle is rotatably supported on a shaft fixed to a magnetic chassis, and the spindle is provided with a rotor yoke, a rotor magnet, and a member to be rotated, A drive motor opposed to the rotor magnet is provided on the chassis, and a power is supplied to the drive coil to rotate a driven member held by the spindle. It comprises a radial ball bearing fitted to a shaft and a thrust bearing provided on the tip end surface of the shaft, forms a female screw hole passing through the rotation axis of the cap portion of the spindle, and screwes a male screw member into the female screw hole. The thrust bearing has a conical recess formed on a tip end surface of the shaft and an inner end of the male screw member. A magnetic path formed between the rotor yoke and the chassis by adjusting the position of the spindle with respect to the chassis by turning the male screw member, the ball being sandwiched between conical recesses formed in the rotor yoke; Since the gap is adjusted, the drive efficiency can be easily increased by simply adjusting the magnetic path gap, and the device can be made thinner while maintaining high rotational accuracy.
In addition, there is provided a rotary drive device capable of reducing costs.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a rotary drive device according to the present invention, and FIG. 2 is a longitudinal sectional view illustrating a conventional rotary drive device. DESCRIPTION OF SYMBOLS 1 ... spindle, 3 ... radial ball bearing, 4 ... chassis (magnetic material), 5 ... shaft, 6 ... thrust ball bearing, 8 ... rotor magnet, 9 ... rotor yoke, 10
... drive coil, 12 ... male screw member, 15 ... member to be rotated, 16 ... conical recess, 18 ... conical recess.

Claims (1)

(57) [Claims] A spindle is rotatably supported on a shaft fixed to a magnetic chassis, and the spindle is provided with a rotor yoke, a rotor magnet and a member to be rotated, and the chassis faces the rotor magnet. A spindle motor type rotary drive device that is provided with a drive coil and energizes the drive coil to rotationally drive a rotated member held by the spindle. A radial ball bearing that fits a bearing portion of the spindle to the shaft. A thrust bearing is provided on the tip end surface of the shaft, a female screw hole is formed through the rotation axis of the cap portion of the spindle, and a male screw member is screwed into the female screw hole. Sandwiched between a conical recess formed on the distal end surface and a conical recess formed on the inner end surface of the male screw member Rotating the male screw member to adjust a position of the spindle with respect to the chassis to adjust a magnetic path gap formed between the rotor yoke and the chassis. apparatus.