JPH04295245A - Spindle motor - Google Patents

Abstract

PURPOSE:To prevent intrusion of grease into a housing through a relatively simple structure without requiring dedicated labyrinth structure by radially extending the outer peripheral face at the supporting wall part of a hub member and the inner peripheral face of the stator core. CONSTITUTION:A plurality of tooth sections 20b are provided, at substantially same intervals, in the peripheral direction on the outer peripheral surface at the base part 20a of a stator 20 and an armature coil 18 is wound around the tooth sections 20b. A stator core 16 is extended upto the base part at the supporting wall section 10b of a hub member 10 under a state where the stator core 16 is mounted on a core supporting member 30. The stator core 16 cooperates with the supporting wall part 10b of the hub member 10 to constitute an air seal structure. Consequently, the supporting wall section 10b and the stator core 16 function as an air seal structure to positively prevent intrusion of grease into the housing from bearings 24, 26 through the gap between the supporting wall section 10b and the stator core 16.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor.

0002

2. Description of the Related Art Generally, a spindle motor includes a housing and a hub member rotatable relative to the housing, with bearing means such as a ball bearing interposed between the two. A rotor magnet is attached to the hub member, and a stator is attached to the housing facing the rotor magnet. Further, a labyrinth seal structure is provided between the housing and the hub member, and this labyrinth seal structure prevents grease etc. from the bearing means from entering the storage chamber (a chamber in which a recording member such as a magnetic disk is stored). prevent.

0003

[Problems to be Solved by the Invention] However, in conventional spindle motors, as described above, in order to provide a dedicated labyrinth structure between the housing and the hub member,
There are problems that need to be solved, such as the structure of the motor becoming complicated and the motor becoming expensive. Further, depending on the structure of the housing, a labyrinth structure cannot be provided, and so-called contamination cannot be sufficiently prevented from occurring.

An object of the present invention is to provide a spindle motor that has a relatively simple structure and can reliably prevent grease and the like from entering the storage chamber.

[0005]

[Means for Solving the Problems] In the spindle motor of the present invention, the hub member includes a hub body to which a recording member is attached;
The stator has a support wall extending in the axial direction from the inner circumference of the hub body, and the stator has a stator core disposed in a space between the hub body and the support wall. The inner circumferential surfaces of the stator core extend sufficiently to overlap in the axial direction with a slight interval in the radial direction, and the support wall portion and the stator core cooperate with each other to function as an air seal structure.

[0006]

[Operation] In the spindle motor of the present invention, the outer circumferential surface of the support wall portion of the hub member and the inner circumferential surface of the stator core overlap in the axial direction with a slight interval in the radial direction and extend sufficiently. The stator core and the stator core cooperate with each other to function as an air seal structure. Therefore, there is no need to provide a dedicated labyrinth structure, and the occurrence of so-called contamination can be reliably prevented with a relatively simple configuration.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partially sectional view showing an embodiment of a spindle motor according to the present invention. The illustrated spindle motor includes a housing 11 and a hub member 10 that is rotatable relative to the housing 11. The hub member 10 has a cylindrical hub body 10a, and an end wall 10c is provided at one end (upper end in FIG. 1) of the hub body 10a, and an annular flange 1 is provided at the other end.
0d is provided. Recording members such as magnetic disks (
(not shown) is placed on this annular flange portion 10d,
It is rotated integrally with the hub member 10 in a predetermined direction. An annular support wall portion 10b extending downward in FIG. 1 is integrally provided on the inner peripheral portion of the end wall portion 10c of the hub member 10. As shown in FIG.

The housing 11 includes a fixed shaft 12, and a stator fixing portion 28 is integrally provided at the lower part of the fixed shaft 12. The stator fixing portion 28 and the fixed shaft 12 may be constructed separately, and the fixed shaft 12 may be fixed to the stator fixing portion 28 by means such as press fitting.

A pair of bearings 24 as bearing means are provided between the upper part of the fixed shaft 12 and the support wall portion 10b of the hub member 10.
and 26 are interposed. A male threaded portion 23 is provided at the lower end of the fixed shaft 12, and this male threaded portion 23 is screwed onto a lower frame (not shown) of the drive device. Also, fixed axis 1
A female threaded hole 22 is formed at the upper end of 2, and by screwing a fixing screw (not shown) into this female threaded hole 22, the upper end is fixed to the upper frame (not shown) of the drive device. .

An annular rotor magnet 38 is disposed on the inner peripheral surface of the hub body 10a of the hub member 10. The stator 20 is disposed opposite to and inside the rotor magnet 38. The stator 20 has a stator core 16 formed by stacking a plurality of core plates 16a, and the stator core 16 has an annular space defined between the hub body 10a and the support wall portion 10b of the hub member 10. 14 and is fixed to the stator fixing part 28 via the core support member 30.

The core support member 30 can be made of an insulating synthetic resin material, and can be integrally formed with the stator fixing portion 28, for example. Stator core 16
By supporting the armature coil via a core support member 30 made of synthetic resin, vibrations generated when the armature coil is excited can be damped by the core support member 30. The stator core 16 is connected to this core support member 3
0 by means such as press fitting. Stator core 1
6, the armature coil 18 is wound as required, and the lead wire 44 from the armature coil 18 is inserted into the space 14.
Externally through.

Above the upper bearing 24 in FIG.
A magnetic fluid seal 36 is provided. This magnetic fluid seal 36 prevents grease and the like from the bearings 24 and 26 from entering the storage chamber (the chamber in which the recording member is stored) through between the fixed shaft 12 and the support wall portion 10b of the hub member 10. To prevent. A scattering prevention member 36 is further provided outside the magnetic fluid seal 36 to prevent the magnetic fluid from scattering. The anti-scattering member 32 is provided with a groove 34 on the side of the support wall 10b of the rotor hub 10 in order to prevent the anti-scattering member 32 from attaching and detaching due to thermal expansion. It is provided so as to be completely adhesively fixed to the circumferential surface.

Next, stator 20 and related elements will be described with reference to FIG. 2 in conjunction with FIG.

The stator 20 has a cylindrical base 20a, and a plurality of teeth 20b (nine in the embodiment) are provided on the outer peripheral surface of the base 20a at substantially equal intervals in the circumferential direction. The armature coil 18 is wound around these teeth 20b as required. In the embodiment, the stator core 16 extends to the base of the support wall portion 10b of the hub member 10 when attached to the core support member 30. This stator core 16 cooperates with the support wall portion 10b of the hub member 10 to form an air seal structure. That is, the inner circumferential surface of the stator core 16 is located outside the outer circumferential surface of the support wall portion 10b, and is arranged with a slight distance from the outer circumferential surface in the radial direction. The distance between the outer peripheral surface of the support wall portion 10b and the inner peripheral surface of the stator core 16 is preferably about 0.05 to 0.25 mm.
It is more preferable to set it to about 0.125 to 0.175 mm. Further, the overlapping length in the axial direction of the two parts located at a certain distance is desirably at least 2 mm or more, and more preferably 3 mm or more.

By setting the support wall portion 10b and the stator core 16 in the above relationship, both function as an air seal structure, so that grease etc. from the bearings 24 and 26 can pass between the support wall portion 10b and the stator core 16. Intrusion into the storage chamber can be reliably prevented.

In order to enhance the sealing effect of the air seal structure, the air seal structure is further constructed as follows.

In the embodiment, a pair of notches 46 are provided at the lower end of the inner circumferential surface of the stator core 16 at an interval of substantially 180 degrees. This notch 46 is used for positioning when winding the armature coil 18 around the stator core 16. This notch 46 is located in the stator core 16.
Only the lower end of (in the example, the lower two core plates 1
6a only), and is embedded in the core support member 30 when the stator core 16 is attached to the core support member 30, as shown in FIG. Therefore, the notch 46 is not exposed above the core support member 30, thereby preventing the inner peripheral surface of the stator core 16 and the support wall portion 10b from being exposed.
It is possible to maintain substantially equal intervals in the circumferential direction with respect to the outer peripheral surface of the
The air seal effect will not deteriorate.

Although one embodiment of the spindle motor according to the present invention has been described above, the present invention is not limited to this specific example, and various modifications and changes can be made without departing from the scope of the present invention. be.

[0019]

[Effect of the invention] In the spindle motor of the present invention,
Since the outer peripheral surface of the support wall portion of the hub member and the inner peripheral surface of the stator core overlap in the axial direction with a slight distance in the radial direction and extend sufficiently, the support wall portion and the stator core function as an air seal structure. Therefore, it is possible to reliably prevent grease and the like from entering the storage chamber with a relatively simple configuration without employing a dedicated labyrinth seal structure.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway sectional view showing an embodiment of a spindle motor according to the present invention.

FIG. 2 is a perspective view showing a stator core in the spindle motor of FIG. 1;

[Explanation of symbols]

10 Hub member 10a Hub body 10b Support wall part 12 Fixed axis 16 Stator core 20 Stator 24, 26 Bearing 28 Stator fixing part 30 Core support member 38 Rotor magnet 46 Notch

Claims (1)

[Claims] 1. A housing, a hub member rotatable relative to the housing, bearing means interposed between the housing and the hub member, and a rotor magnet attached to the hub member. , a spindle motor comprising a stator mounted on the housing facing the rotor magnet, the hub member extending in the axial direction from a hub body to which the recording member is mounted, and an inner peripheral portion of the hub body. the stator has a stator core disposed in a space between the hub body and the support wall, and the outer peripheral surface of the support wall and the inner peripheral surface of the stator core have a radius. 1. A spindle motor characterized in that the support wall portion and the stator core extend sufficiently to overlap in the axial direction with a slight interval in the direction, and the support wall portion and the stator core cooperate with each other to function as an air seal structure.