JP3327409B2 - motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor, and more particularly to a motor having a gear formed on a peripheral side surface of a rotor case.

[0002]

2. Description of the Related Art Conventionally, in a motor 1 of this type, a rotor case 3 of a rotating shaft 2 is fixed as shown in FIG. The net 4 is fixed.

An FG magnet 5 for generating a frequency for detecting a rotational phase is fixed to a peripheral side surface of the rotor case 3. Further, a gear member 6 for transmitting the rotation of the rotor case 3 to an external device is formed on the peripheral side surface, and a transmission gear (not shown) meshes with a gear 6A of the gear member 6. It has been made like that.

[0004]

The gear member 6 of this type is formed of a resin material. Depending on the residual stress at the time of molding and the condition of the mold release, as shown in FIG. Peeling is likely to occur.

As one method for solving this problem, a material having a low melting point is used as the FG magnet 5 made of a resin magnet, and the F
A method has been considered in which a molecular bond is generated at a contact surface with the G magnet 5 so that the gear member 6 is not peeled off from the FG magnet 5. However, according to such a method, there is a problem that the FG magnet 5 is deteriorated or deformed, and it is still insufficient as a solution.

Further, when the gear member 6 is formed on the peripheral side surface of the rotor case 3, the gear member 6 is prevented from rotating.
The gear member 6 needs to be formed up to the inside of the rotor case 3. In this case, as shown in FIG. 4C, the skirt portion 3A of the rotor case 3 is shortened, so that the leakage flux B of the rotor magnet 4 is increased. As a result, there is a problem that the leakage magnetic flux B is sensed by the magnetoresistive element provided corresponding to the FG magnet 5, and the FG signal is deteriorated.

The present invention has been made in view of the above points, and an object of the present invention is to propose a motor capable of preventing the gear member from peeling and reducing the leakage magnetic flux.

[0008]

According to the present invention, there is provided a skirt portion 13B extending downward from a peripheral edge of a disk portion, and a protrusion protruding outward from a tip of the skirt portion 13B. A rotor case 13 formed with a portion 13A, an annular rotor magnet 4 fixed to the lower surface of the disk portion, and an annular FG magnet 15 for annular rotation phase detection fixed to the outer peripheral surface of the skirt portion 13B. And an outer peripheral surface of the skirt portion 13B such that at least a part of the inner side is sandwiched between the FG magnet 15 and the protruding portion 13A. An annular gear member 16A fixed to the surface is provided.

Further, the skirt portion 13B is formed to have a length for shielding the magnetic flux leaking from the magnet 4.

Further, the gear member 16 is made of a resin gear.

[0011]

The FG magnet 15 fixed to the skirt portion 13B is sandwiched between the projecting portion 13A of the rotor case 13 and the FG magnet 15 fixed to the skirt portion 13B of the rotor case 13.
The gear member 16 can be prevented from peeling off.

Further, by forming the skirt portion 13B to have such a length as to block the leakage magnetic flux from the magnet 4, the leakage magnetic flux can be reduced.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

In FIG. 1, in which parts corresponding to those in FIG. 4 are denoted by the same reference numerals, the motor 10 has a rotating shaft 2 rotatably supported on a stator member 21 fixed to a substrate 24 via bearings 23A and 23B. Have been.

A rotor case 13 is fixed to the tip of the rotating shaft 2, and a rotor magnet 4 is fixed to a lower surface of the rotor case 13. A coil 22 is provided on the substrate 24 at a position facing the rotor magnet 4. By supplying a drive current to the coil 22, the rotor unit including the rotor magnet 4, the rotor case 13, and the rotating shaft 2 can be rotated.

Further, as shown in FIG.
An FG magnet 15 is formed on the peripheral side surface of the motor 10, and its frequency changes (for detecting a rotational phase) according to the rotational speed of the motor 10 via the magnetoresistive element 20.
A G signal is output.

Here, as shown in FIG.
The skirt portion 13B formed by bending the peripheral side surface portion of No. 3 includes:
A protruding portion 13A further protruding outward from the front end portion is formed. A gear member 16 made of a resin material is provided on an outer peripheral portion of the protruding portion 13A. This gear member 1
6 is formed so as to be sandwiched between the projecting portion 13A of the rotor case 13 and the FG magnet 15.

Further, the skirt portion 13B is the rotor case 1
The length is formed so as to block magnetic flux leakage from the magnet 4 fixed to the magnet 3.

In the above configuration, the gear member 16 is sandwiched between the projecting portion 13A of the rotor case 13 and the FG magnet 15, so that the gear member 16 can be prevented from peeling off from the FG magnet 15.

Further, by forming the gear member 16 in such a shape as to be sandwiched between the projecting portion 13A of the rotor case 13 and the FG magnet 15, the gear member 16
The joining force with respect to the rotor case 13 is improved, and the gear member 16 can be prevented from easily turning with respect to the rotor case 13.

Further, by forming the skirt portion 13B of the rotor case 13 having the protruding portion 13A formed so as to be long enough to block the leakage magnetic flux from the rotor magnet 4, the leakage magnetic flux from the rotor magnet 4 is reduced. can do. Therefore, it is possible to prevent the FG signal output from the magnetoresistive element 20 (FIG. 1) from being deteriorated by the leakage magnetic flux.

According to the above configuration, the skirt portion 13B of the rotor case 13 is formed to have a length that can block the leakage magnetic flux from the rotor magnet 4, and the skirt portion 13B protrudes outward from the skirt portion 13B. By forming the portion 13A, the leakage magnetic flux of the rotor magnet 4 can be reduced, and the gear member 16 formed on the outer peripheral portion of the rotor case 13 is prevented from peeling off from the FG magnet 15 and rotating around the rotor case 13. be able to.

[0023]

[0024]

As described above, according to the present invention, a projecting portion projecting outward from the tip of the skirt portion of the rotor case is formed, and the rotational phase fixed to the outer peripheral portion of the skirt portion is detected. The gear member fixed to the outer peripheral portion of the skirt portion is sandwiched between the FG magnet and the ridge portion protruding outward from the tip of the skirt portion, and the skirt portion of the rotor case leaks the magnet. By forming the motor to a length that can shield magnetic flux, a motor that can prevent peeling of the gear member and reduce leakage magnetic flux can be realized.

[Brief description of the drawings]

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

FIG. 2 is a plan view of a motor according to the present invention.

FIG. 3 is a partial sectional view showing a detailed configuration of a rotor case according to the present invention.

FIG. 4 is a partial sectional view showing a conventional example.

[Explanation of symbols]

1, 10 ... motor, 2 ... rotating shaft, 3, 13 ... rotor case, 3A, 13B ... skirt part, 4 ... rotor magnet, 5, 15 ... FG magnet, 6, 16 ...
... Gear member, 13A ... Protrusion.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-166761 (JP, A) JP-A-63-55777 (JP, U) JP-A-63-187583 (JP, U) (58) Investigation Field (Int.Cl. ⁷ , DB name) H02K 29/14

Claims (3)

(57) [Claims] (1)Skirt extending downward from the periphery of the disc
And a protrusion projecting outward from the tip of the skirt portion.
A rotor case formed with An annular rotor magnet fixed to the lower surface of the disk
And An annular rotational phase fixed to the outer peripheral surface of the skirt
FG magnet for detection, Adjacent to the FG magnet on the outer peripheral surface of the skirt
And at least part of the inside is
So that it is sandwiched between the G magnet and the protruding portion.
An annular gear fixed to the outer peripheral surface of the skirt portion
Components Equipped with A motor characterized in that: 2. The method according to claim 1, wherein the skirt portion is the rotor magnet.
Have a length that shields the magnetic flux leakage to the FG magnet.
The motor according to claim 1, characterized in that. 3. The gear member is formed by molding a synthetic resin material.
The motor according to claim 1, characterized in that that.