JP2604059Y2 - Rotation detection device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation detecting device,
In particular, the present invention relates to a device in which a magnet is used as a detected element and a magnetically sensitive element is used as the detected element, and for example, relates to a device that is effectively used to detect the rotation speed of a motor mounted on an automobile.

[0002]

2. Description of the Related Art In general, a motor with a worm gear reduction device is widely used as a driving device for driving a power window or a power seat of an automobile. In this type of motor, the number of rotations of the motor is detected in order to control the opening / closing of a window and the position of a seat.

Conventionally, as a rotation detecting device used to detect the number of rotations of a motor of this type, a cylindrical magnet in which N and S poles are alternately arranged in a circumferential direction is provided with a commutator on a rotating shaft of the motor. It is configured to detect the number of rotations of the motor by detecting the magnetism of the magnet with a magnetically sensitive element such as a Hall element disposed near the motor rotation axis. There is something.

[0004] When a magnet as a detected element is fixed to a rotating shaft in the conventional rotation detecting device having the above-described configuration, a structure is employed in which the magnet is fixed using an adhesive.

[0005]

However, the above-described conventional rotation detecting device has the following problems because the structure in which the magnet is fixed to the rotating shaft by an adhesive is employed. (1) In order to secure a practically desired strength, an adhesive curing time of at least about 10 minutes is required. (2) If oil is attached to the rotating shaft or the magnet, it cannot be bonded. Therefore, an oil removing step is required, and the productivity is reduced. (3) Since the fixing strength varies depending on the applied amount of the adhesive, strict control of the applied amount is required.

An object of the present invention is to provide a rotation detecting device capable of mounting a magnet on a rotating shaft without using an adhesive.

[0007]

Rotation detecting device according to the present invention In order to achieve the above object, according to, N pole S pole circular cylinder shape arranged alternately in the circumferential direction the magnet is mounted on the rotary shaft, the magnetic of the magnet In a rotation detection device in which a sensitive detector is arranged near the rotation axis, a plurality of holding members have a cylindrical shape.
Magnet holders arranged and connected by connecting parts
Are integrally molded using an elastic resin,
With the magnet fitted to the outer periphery of the holding member group,
The magnet holder is pressed into the rotating shaft,
The retainer sandwiched between the outer periphery of the rotating shaft and the inner periphery of the magnet
Due to the elastic force caused by the compressive deformation of the member group, the magnet
Is fixed to the rotating shaft via the magnet holder.
And the groove is formed on the outer periphery of the rotating shaft.
Some of the net holder is characterized in that it is engaged.

[0008]

According to the above-mentioned means, without using an adhesive,
Since the magnet can be mechanically fixed to the rotating shaft, productivity of the assembling work can be improved, and automation can be performed.

[0009]

1 shows a rotation detecting device according to an embodiment of the present invention, in which (a) is an exploded perspective view and (b) is a partially cut front view. FIG. 2 is a front sectional view showing a motor with a worm gear reduction device in which the rotation detecting device is used.

In this embodiment, a motor with a worm gear reduction device in which the rotation detecting device according to the present invention is used includes a motor 1 as a drive source and a worm gear reduction device 2 as a reduction mechanism. . The housing 3 of the motor 1 is composed of a yoke 4 formed in a cylindrical shape with one end opened, and an end bracket 5 covered by the opening of the yoke 4. On the inner periphery of the yoke 4, a plurality of magnets 6 constituting field poles are fixedly arranged at equal intervals in the circumferential direction. A rotating shaft 7 is concentrically mounted in the yoke 4 so that both end bearings 8 and 8 and an intermediate bearing 9 are provided.
It is rotatably supported by.

An armature 10 is disposed on the rotating shaft 7 so as to face the field pole magnet 6, and is fixedly provided on one side of the armature 10 of the rotating shaft 7. A commutator 11 is fixedly provided on one side of the rotating shaft 7. ing. A ring-shaped brush holder stay 12 made of an insulating material is fitted and fixed to the end bracket 5 of the motor housing 3, and a pair of brushes is attached to the stay 12 by a brush holder (both in FIG. (Not shown). Both brushes are configured to be slidably contacted with the commutator 11 by the urging force of a brush spring (not shown) supported by the brush holder, and to supply power to the armature 10. An external terminal 14 and a circuit breaker 15 are electrically connected to the brush holder stay 12. The circuit breaker 15 automatically shuts off the circuit when a short circuit or a load exceeding a design value is applied.

On the other hand, the worm gear reduction device 2 includes a gear housing 17, and the end bracket 5 of the motor housing 3 is formed integrally with the gear housing 17. The rotation shaft 7 of the motor 1 is inserted through the end bracket 5 into the gear housing 17. And the gear housing 1 of the motor rotating shaft 7
A worm 18 is integrally formed on the outer periphery of the insertion portion into the worm 7. An output shaft 19 of the worm gear reduction device 2 is rotatably supported at a substantially central portion of the gear housing 17 by being inserted in a direction perpendicular to the rotation shaft 7.
The worm wheel 20 is fixed in the gear housing 17. The worm wheel 20 has a rotating shaft 7
Is engaged with the worm 18 engraved at the center. Therefore, the output shaft 19 is connected to the worm 1 by the motor rotation shaft 7.
8. The rotation is reduced via the worm wheel 20. The output shaft 19 is linked to a desired load such as a power window or a power seat outside the gear housing 17. Reference numeral 16 denotes a thrust receiver for the motor rotation shaft 7.

In the present embodiment, a magnet 22 as a detector is mounted on the outer periphery of the rotating shaft 7 adjacent to the commutator 11. A magnetically sensitive element 21 as a detector is disposed outside the magnet 22 so as to face the magnet 22 and is fixedly supported by a support 13 projecting from the brush holder stay 12. The magnetic sensing element 21 as a detector is constituted by, for example, a Hall element. When the magnetic sensing element 21 senses the magnetic pole of the magnet 22, a signal is supplied to an external rotation judging device (not shown). The rotation of the rotating shaft 7 is determined.

The magnet 22 is formed in a cylindrical shape,
The poles and the N poles are alternately arranged in the circumferential direction. And
A recess 23 is integrally formed on the end face of the magnet 22 opposite to the commutator 11,
Is designed to position the magnet holder 25 in the circumferential direction with respect to the magnet holder 25 described later. The outer circumferential surface of the rotating shaft 7 has a positioning annular groove 2 for regulating movement of the magnet 22 in a direction away from the commutator 11.
4 has been submerged.

The rotation detecting device has a magnet holder 25. The magnet holder 25 is integrally formed using a resin having appropriate elasticity, and includes a plurality of holding members 26. Each holding member 26 is formed in a rectangular plate shape having a circular cross section,
They are arranged at equal intervals in the circumferential direction on a circle whose radius is the curvature of the arc. Each holding member 26 is arranged in a cylindrical shape in parallel with the axial direction and with both ends aligned, and is formed in a circular ring shape at one end (hereinafter, referred to as a rear end). They are integrally connected by a connecting portion 27. Then, the holding member 26 in the natural state
Is set to be slightly larger than the difference between the radius of the outer diameter of the rotating shaft 7 and the radius of the cylinder inner diameter of the magnet 22.

On the outer periphery of the front end of each holding member 26, a front engaging portion 28 is provided so as to project radially outward.
A rear engaging portion 29 is provided on an outer periphery of the connecting portion 27 corresponding to an outer periphery of the rear end of the rear projection 6 so as to project radially outward. And
The distance between the rear end surface of the front engagement portion 28 and the front end surface of the rear engagement portion 29 is set equal to the axial width of the magnet 22, and both engagement portions 28, 29 fit on the outer periphery of the holding member 26. The two end faces of the combined magnet 22 can be engaged with each other.

The connecting member 27 is provided with a plurality of locking claws 30 projecting rearward. The locking claws 30 are arranged at equal intervals in the circumferential direction and parallel to the axial direction, and convex portions 31 are arranged on the same circle at the rear end inner periphery to project radially inward. Has been established. The projection 31 is formed so as to be able to fit radially inward into the annular groove 24 laid down on the rotating shaft 7. A detent protrusion 32 is provided on the front end surface of the connecting member 27 so as to project forward in the axial direction.
It is formed so as to be able to fit into the second rotation preventing recess 23.

Next, the operation of assembling the magnet 22 to the rotating shaft 7 by the magnet holder 25 will be described. First, the magnet 22 is fitted around the outer periphery of the holding members 26 of the magnet holder 25. At this time, the front end of each holding member 26 is moved radially inward of the cylindrical
The magnet 22 is inserted into the cylindrical hollow portion of the magnet 22 while being bent by the elasticity of the resin itself. When each holding member 26 is inserted into the magnet 22 until the rear engagement portion 29 comes into contact with the rear end surface of the magnet 22, the holding member 2
Since the front engaging portion 28 of FIG. 6 gets over the inner peripheral edge of the magnet 22, the front engaging portion 28 is engaged with the front end surface of the magnet 22 by the elastic restoring force of the holding member 26. In this state, the state in which the magnet 22 is prevented from moving in the axial direction by the magnet holder 25 is maintained.

Further, when the magnet 22 is assembled to the magnet holder 25, the detent recess 23 of the magnet 22 and the detent projection 32 of the magnet holder 25 are aligned and fitted. The fitting of the concave portion 23 and the convex portion 32 causes the magnet 22 to be prevented from rotating by the magnet holder 25.

The magnet holder 25 with the magnet 22 assembled in this way is fitted to the outer periphery of the rotating shaft 7 from one end on the worm 18 side. While the magnet holder 25 is being fitted to the rotating shaft 7,
Each locking claw 30 bends radially outward due to the elasticity of the resin itself, and the convex portion 31 slides on the outer peripheral surface of the rotating shaft 7. Then, when reaching the annular groove 24 on the outer periphery of the rotary shaft 7, the convex portion 31 is fitted into the annular groove 24 by the elastic restoring force. The fitting of the convex portion 31 into the annular groove 24 causes the magnet holder 25 to be in a state where the rotation shaft 7 is prevented from moving in the axial direction.

When the magnet holder 25 is pressed into the rotary shaft 7, the holding member 26 is compressed by being pressed between the inner circumference of the magnet 22 and the outer circumference of the rotary shaft 7. In this state, the magnet 22 and the rotating shaft 7 are fastened, and the magnet 22 and the rotating shaft 7 are relatively fixed. A knurl 7a for preventing the commutator 11 and the armature 10 from rotating is formed on the outer periphery of the rotating shaft 7 in an elongated linear uneven pattern. By further extending the knurl 7a, the holding member 26 compressed by the magnet 22 and the rotating shaft 7 is formed.
Are deformed along the concave and convex portions of the knurl 7a, so that they are engaged with each other. For this reason, by this engagement state under the compression deformation, the magnet holder 25 is prevented from rotating around the rotating shaft 7 and the magnet 22 is more securely fixed.

As described above, since the work of assembling the magnet 22 to the rotating shaft 7 can be performed by a simple operation without using an adhesive, the workability of the assembling work can be improved, and the automation can be performed. Becomes possible. In addition, since the press-fitting operation of the magnet 22 itself into the rotating shaft 7 is not used, damage to the magnet 22 and the bearing surface of the rotating shaft 7 can be avoided, and the magnet can be firmly fixed to the rotating shaft.

Next, the operation of the rotation detecting device will be described. When power is supplied to the armature 10 via the brush and the commutator 11, the rotation of the armature 10 causes the rotation shaft 7 to rotate. Since the magnet 22 is mounted on the rotating shaft 7 so as to be integrally rotated by the magnet holder 25, the magnet 22 is rotated in synchronization with the rotation of the rotating shaft 7.

When the magnetic sensing element 21 arranged opposite to the magnet 22 senses a change in the magnetic pole with the rotation of the magnet 22, a signal corresponding to the change in the magnetic pole is output. It is determined that the shaft 7 is rotating. Conversely, when a change in the magnetic pole is not detected by the magnetically sensitive element 21, it is determined that the motor rotation shaft 7 is not rotating.

FIG. 3 is a diagram showing a rotation detecting device according to another embodiment of the present invention. The second embodiment differs from the first embodiment in that the front end surface of the magnet 22 is in contact with the rear end surface of the commutator 11 instead of omitting the front engagement portion 28 of the holding member 26. . That is, the second embodiment
, The forward movement of the magnet 22 is restricted by the commutator 11.

In the above embodiment, the case where the concave portion 23 is provided on the magnet 22 and the convex portion 32 is provided on the magnet holder 25 has been described. However, the convex portion is provided on the magnet 22 side and the magnet holder 25 side is provided. May be provided with a concave portion.

The groove in which the locking claw is locked is a series of annular grooves 24.
In addition to this, it may be formed intermittently, in which case a detent action is also exerted.

[0028]

[Effects of the Invention] As described above, according to the present invention,
The magnet can be fixed to the rotating shaft without using an adhesive, so that the workability of the assembling work can be improved and automation can be performed. Also, the magnet holder
Manufactured in advance in a separate molding process independent of magnet manufacturing
Manufacturing and magnet production
Can be made simultaneously with the production of
It can improve efficiency and increase manufacturing yield.
Can be

[Brief description of the drawings]

FIG. 1 shows a rotation detecting device according to an embodiment of the present invention, wherein (a) is an exploded perspective view and (b) is a partially cut front view.

FIG. 2 is a front sectional view showing a motor with a worm gear reduction device in which a rotation detecting device is used.

3A and 3B show a rotation detecting device according to another embodiment of the present invention, wherein FIG. 3A is a partially cut front view, and FIG.
FIG. 3C is a cross-sectional view taken along a line b, and FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Motor, 2 ... Worm gear reduction device, 3 ... Motor housing, 4 ... Yoke, 5 ... End bracket, 6
... magnet, 7 ... rotary shaft, 8, 9 ... bearing, 10 ... armature, 11 ... commutator, 12 ... brush holder stay, 13 ... support, 14 ... external terminal, 15 ... circuit breaker, 16 ... thrust receiver, 17 ... Gear housing, 18 worm, 19 output shaft, 20 worm wheel, 21 magnetically sensitive element (detector), 22 magnet, 23 detent recess, 24 annular groove, 25
Magnet holder, 26 holding member, 27 connecting member, 28 front engagement portion, 29 rear engagement portion, 30 locking claw, 31 convex portion, 32 detent convex portion.

Claims (2)

(57) [Scope of request for utility model registration] Vicinity of 1. A N pole S pole is a magnet of circular <br/> tubular shape are arranged alternately in the circumferential direction is mounted on the rotary shaft, the rotation axis detectors sensitive to magnetism of the magnet In the rotation detecting device arranged in the above, a plurality of holding members are arranged in a cylindrical shape and
Resin with elastic magnet holder
The magnet is fitted into the outer periphery of the holding member group.
The magnet holder is pressed into the rotating shaft
Between the outer periphery of the rotating shaft and the inner periphery of the magnet.
Due to the elastic force caused by the compressive deformation of the holding member group, the
Gnet is attached to the rotating shaft via the magnet holder.
The magnet holder is fixed in a groove formed on the outer circumference of the rotating shaft.
Rotation detecting device in which a part of the loaders is characterized in that it is engaged. 2. A groove formed on an outer periphery of the rotating shaft is provided at a front end.
It is formed in a series or intermittently in the circumferential direction on the outer circumference of the rotating shaft.
Locking groove, or formed on the outer periphery of the rotating shaft in the axial direction.
The rotation detection device according to claim 1, wherein the rotation detection device is a knurl .