JPH09201003A - Motor with speed changing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the position of a window glass with high accuracy when the glass is used for a power window device by maintaining the axial positron of a worm gear against a load applied to the gear. SOLUTION: A worm gear 31 is held between stoppers 133 which are respectively brought into contact with both end faces of the gear 31 in the axial direction and supported by the internal surface of a motor case 1 so as to prevent the movement of the gear 31 on a rotating shaft 23. Even when an external force transmitted from a worm wheel 32 is applied to the gear 31 in the axial direction, the axial position of the gear 31 on the shaft 23 can be fixed and a motor can be driven with high accuracy by maintaining a relative positional relation between the angles of rotation of the shaft 23 and the wheel 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor to which a high load is applied, such as an electric motor for a power window device of an automobile, and more particularly to an electric motor integrally provided with a worm gear constituting a speed change mechanism on a motor rotating shaft.

[0002]

2. Description of the Related Art As an electric motor of this type (hereinafter referred to as a motor), the applicant of the present application has previously proposed a small motor used as a drive source for a power window device of an automobile. In this type of motor, a worm gear is integrally provided on the rotary shaft of the motor, and a part of the motor case is formed into a cylindrical container, which is configured as a worm wheel case,
A worm wheel that is meshed with the worm gear is housed inside the worm wheel case to form a reduction mechanism. A pulley is connected to the rotary shaft of the worm wheel, and a wire for driving the power window is wound around the pulley. Therefore, in this motor, when the rotary shaft of the motor is rotationally driven, the worm gear integrated with the rotary shaft is rotated, and the worm wheel meshed with the worm gear is decelerated and rotated. Accordingly, the pulley integrated with the worm wheel in the rotation direction is rotated, and the wire can be moved to move the windshield up and down.

[0003]

The inventors of the present invention have studied this type of motor, and as a result of various causes when moving the window glass, an extremely large load is applied to the motor at the start of driving the window glass. It has been confirmed that it has been added. This load is transferred from the wire to the pulley and then to the worm wheel,
The load generated on the worm wheel at the start of driving is applied to the worm gear in its axial direction. On the other hand, a load is applied to the worm gear in the axial direction via the motor rotation shaft. Normally, in the power window device, since the position of the window glass is controlled by the rotation angle of the motor in order to control the position of the window glass with high accuracy,
When these loads cause the worm gear to move relative to the rotary shaft in the axial direction and the direction around the axis, a reversing sound is produced.
In addition, the rotation angle of the worm wheel is displaced, and this displacement is transmitted to the wire through the pulley, so that it may not be possible to control the position of the windshield with high accuracy.

By the way, since the worm gear is press-fitted into the motor rotary shaft, it is necessary to prevent relative movement between the worm and the rotary shaft due to the above-mentioned load. In this case, in order to integrate the both in the direction around the axis, this can be dealt with by forming serrations or key grooves on the fitting surface between the rotary shaft and the worm gear. However, there is no suitable method in the axial direction, and therefore, it is necessary to perform press fitting so as to enhance the fitting force between the two. However, such press-fitting with a high fitting force is technically difficult and requires special skill and skill, which causes a problem of extremely high manufacturing cost.

On the other hand, even if the worm gear is not relatively moved on the motor rotation shaft, the load applied to the worm gear is transmitted to the rotation shaft of the motor as it is. Normally, the motor rotating shaft is provided with thrust members that receive axial loads at both axial ends, and therefore the loads are transmitted as is to the motor case that supports the thrust members. In recent years, the motor case is often made of resin to reduce the weight of the motor.
The load in the thrust direction damages the motor case at the shaft end of the rotary shaft, causing damage or cracks.
There is a problem that the waterproof property is deteriorated at these damaged parts and cracked parts.

In order to deal with such a problem,
When the case of the motor mechanism part is made of a metal material, it is conventionally formed by press working of hard metal.
There is a problem that the weight is high and the manufacturing and assembling processes are complicated. Also, when the motor case is divided into a base and a cover, it is necessary to insert a sealing material in the abutting portion of the two, and a groove for supporting the sealing material is formed in the base and the cover. There is also a problem that it is necessary to form the sealing material in at least one side and to install the sealing material in the groove at the time of assembly, which makes manufacturing and assembly difficult.

It is an object of the present invention to maintain the axial position of the worm gear even with respect to the load applied to the worm gear, and to enable highly accurate position control of the window when used in a power window device. The purpose is to provide an attached motor. Another object of the present invention is to provide a motor that ensures waterproofness while reducing the weight of the motor case and facilitating manufacture and assembly.

[0008]

According to the present invention, there is provided a motor with a speed change mechanism, the inner wall of the motor case facing the axially opposite end surfaces of a worm gear fitted and attached to a motor rotating shaft mounted in the motor case. Stoppers for contacting both axial end faces of the worm gear and restricting axial movement of the worm are disposed and supported at the points. Further, the motor case is configured to include a base and a case cover that are divided into two parts in a plane parallel to the plane including the axis of the rotating shaft, and the base is formed by a die casting method of aluminum or aluminum alloy, and the case cover is It is formed by resin molding, and the stopper is disposed and supported by the base. Further, it is preferable that the case cover is made of a hard resin, and a seal portion made of a soft resin is formed on the contact surface with the base.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings. This embodiment shows an example in which the present invention is applied to a small motor as a drive source of a power window device used in an automobile. 1 is an external view thereof, FIG. 2 is a partially exploded perspective view thereof, FIG. 3 is a horizontal sectional view taken along the line AA of FIG. 1, and FIG. 4 is a vertical sectional view taken along the line BB.
The motor case 1 is formed by the case cover 12 that covers the base 11. A part of the motor case 1 is provided as a case portion 2 of the speed reduction mechanism, which will be described later.
Further, the pulley cover 14 is configured to be integrally attached.

The base 11 is made of a material having a relatively high strength, and in this embodiment, it is formed by die casting of aluminum or an aluminum alloy (hereinafter, aluminum, etc.). Also, the case cover 1
2 is mainly made of a hard resin, but as shown by the hatched portion in FIG. 5A, a seal portion 15 made of a soft resin is formed on the entire periphery of the opening portion abutting on the base 11. Then, the contact surface with the base 11 is sealed. As shown in FIG. 5B, this seal portion is formed by filling the groove 12a formed in the inner surface of the case cover 12 with an elastomer or the like. In addition, the case cover 12
Is fitted to the base 11 by a plurality of hooks (not shown) provided in the peripheral portion thereof, and further fixed by embedding bolts 16 provided in a plurality of peripheral portions to be integrated. The pulley cover 14 is also made of hard resin, and is fitted and attached to the case cover 12.

In the base 11, a cylindrical fixed magnetic pole 21 is fixedly supported along a pair of opposite sides of a pair of magnets 21a having an arc-shaped cross section. The rotating magnetic pole 22 of the motor is installed between the fixed magnetic poles 21 to form the armature 2 of the motor. The rotating magnetic pole 22 is fixedly supported by a rotating shaft 23 extending over a region from the base 11 to the reduction mechanism case portion 13. The rotating magnetic pole 22 is, for example, a metal rotor, although not shown. The coil is wound around the rotor, and the end of this coil is connected to a plurality of sliding electrodes 24 arranged and supported around the axis of the rotating shaft at one end of the rotating magnetic pole.

The rotary shaft 23 is axially supported by the base 11 by bearings 25a, 25b, 25c at positions near the other end of the rotary magnetic pole and at both ends of the rotary shaft 23, respectively. The bearings 25a and 25b have a spherical outer shape,
A through hole is formed in the center direction, and the rotary shaft 23 is inserted into the through hole. The bearing 25c has a cylindrical shape and is notched in the upper portion, and the rotary shaft 23 is housed in the notch. Then, hemispherical recesses 111a and 111b provided at corresponding positions of the base 11,
When the bearings 25a, 25b, 25c are fitted in the 111c, and the bearings 25a, 25b, 25c are sandwiched between them when the case cover 12 is attached to the base 11, the rotary shaft 23 is A shaft is rotatably supported in the motor case 1. The bearing 25c is provided with a detent 25c ', and the groove 111 provided in the recess 111c is provided.
It is fitted to c '.

Further, abutting portions 15a, 15b, 15c which are part of the seal portion 15 provided on the case cover 12 are arranged for the bearings 25a to 25c, respectively (FIG. 5). (See (a)), the abutting portions 15a, 15b, 15c have a tip end surface formed in a concave shape as shown in FIG. 7, and each of the bearings 25a, 25b having a spherical tip end surface. , 25c are elastically pressed to ensure the support by the base 11.
Further, a sliding unit 26 corresponding to the sliding electrode 24 is arranged inside the base 11, and is brought into contact with the sliding electrode 24 to form a commutator structure.

A worm gear 31 forming a part of the reduction gear mechanism 3 is fixed to a portion of the rotation shaft 23 extending to the reduction gear mechanism case portion 13. The worm gear 31 is press-fitted and integrated with the rotary shaft 23. In addition, the reduction mechanism case portion 13 includes a rotating shaft 23.
Inner walls 131 on both sides in the axial direction are arranged close to both ends of the worm gear 31. Then, as shown in the partially exploded perspective view of the main part in FIG. 6, the inner wall surfaces of these inner walls 131 have shallow grooves 132 that are orthogonal to the axial direction in the depth direction thereof.
A stopper 133 is fitted between the groove 132 and both end surfaces of the worm gear 31. The stopper 133 is made of a material having low abrasion at a high PV value, such as polyimide resin, and having a low coefficient of friction, and has a rectangular outer shape corresponding to the groove 132, and a tip portion thereof. To U-shaped concave groove 133a is formed. Then, the concave groove 133a is inserted into the groove 132 from the opening side of the case portion 13 toward the bottom side so that the concave groove 133a is fitted to the outer side in the radial direction of the rotary shaft 23. And
In this inserted state, as shown in FIG. 3, it is possible to hold the both ends of the worm gear 31 in the axial direction by the stoppers 133 and hold the axial position of the worm gear 31.

Further, in FIGS. 1 and 5, a fixed shaft 134 is erected at the center position of the inner bottom surface of the transmission mechanism case 13 having a cylindrical shape, and the fixed shaft 134 has a shaft hole. The worm wheel 32 having a short cylindrical shape is rotatably supported by the fixed shaft 134 so as to be rotatable. The worm wheel 32 has radial ribs 32a formed at a plurality of positions on the circumference, and the gear 32 is provided on the outer peripheral surface thereof.
b is formed and meshed with the worm gear 31. A damper 35 made of an elastic material such as rubber is installed inside the cylinder of the worm wheel 32.
A spline rotating body 36 is connected to the. In this damper 35, a plurality of radial recessed grooves 35a provided at a plurality of circumferences are fitted to the ribs 32a of the worm wheel 32, and a spline rotating body 36 is provided in a recess 35b formed between the recessed grooves 35a. The projection 36c provided on the above is fitted. In addition, the spline rotating body 36 is integrally formed with a protrusion 36c that fits into the recess 35b of the damper 36 on one surface of the disc portion 36a, and the spline shaft 36b projects at the center of the disc portion 36a. Has been formed. The spline shaft 36b has a hole 1 formed in the case cover 12.
21 is projected outside the motor case 1.

The case cover 12 has a circumferential wall 12 partially cut off in the region of the upper surface of the transmission mechanism case portion 13.
2 is integrally formed so as to stand upright, and a pulley described later can be housed therein. This circumferential wall 122 has a circumference 2
Cutouts 122a, 122b are formed at the positions, and a thin wire-shaped lower wire guide tube 123 is formed in one cutout 122a extending in the tangential direction of the circumferential wall 122. The wire guide tube 123 is formed in a circular gutter shape in which a part of the upper peripheral surface is opened.

Further, inside the circumferential wall 122, a pulley 34 having a bottomed cylindrical shape is installed. This pulley 34
A wire 37 for vertically driving the window, which is the load as described above, is wound around the wire, and one end of the wire 37 is inserted into the wire guide tube 123. The shaft hole of the pulley 34 is formed as a spline shaft hole, and the spline shaft 36b of the spline rotating body 36 is fitted into the spline shaft hole and is integrated in the rotation direction.

The wire cover 14 is formed in a disk shape having a diameter substantially equal to that of the circumferential wall 122 on the transmission mechanism case portion 13, and an upper wire guide cylinder 141 is formed in a part thereof in the tangential direction. This upper wire guide tube 141
The lower part of the circumference is opened so that it is formed in a downward circular gutter shape. Then, the engagement pieces 142 provided at a plurality of positions on the circumference of the wire cover 14 are fitted into the recesses 124 provided at the corresponding positions of the circumferential wall 122 with its elastic deformation force, so that the wire cover 14 is made into a case. It is integrated with the upper surface of the cover 12. At this time, the pulley 34
Of the wire 37 wound around the
The part inserted through b is housed in the upper wire guide cylinder 141.

As shown in FIG. 7 which is an enlarged vertical sectional view taken along the line CC of FIG. 1, a part of the case cover 12 has a semi-cylindrical shape in which a part for accommodating the armature 2 is projected upward. In this portion, a through hole 125 that communicates with the inside and outside is opened at a position corresponding to the commutator unit 26, and the electrode terminal 27 is inserted into this through hole 125. The electrode terminal 27 is configured such that its inner end is electrically connected to the commutator unit 26 when the case cover 12 is fastened to the base 11. In addition, the outer end of the electrode terminal 27 is configured as a connector with a cylindrical portion 126 integrally formed with the case cover 12 so as to surround them, and an external connector (not shown) is connected to the cylindrical portion 126.
The electrode terminal 27 is configured to be electrically connected to the external connector by being inserted therein.

In the motor of this embodiment having such a configuration, the fixed magnetic pole 21, the rotating magnetic pole 22, and the commutator structure 2 are provided.
When the motor composed of 4, 26 is energized, its rotating shaft 2
When 3 is driven to rotate, the worm gear 31
Is rotated, and this rotational force is transmitted to the worm wheel 32. The rotational force of the worm wheel 32 is further transmitted to the pulley 34 via the damper 35 and the spline rotating body 36, and the pulley 34 is rotated. As a result, the wire 37 wound around the pulley 34 is moved in the lengthwise direction, and thereby the windshield (not shown) is moved upward or downward depending on the rotation direction of the motor.

Then, as when starting the rotation of the motor,
When the load (static load) at the time of starting the movement of the windshield is applied as a shock to the motor via the wire 37,
This impact is mitigated by the action of the damper 35 existing between the pulley 34 and the worm wheel 32. The impact that is not relieved by the damper 35 is transmitted to the worm gear 31 through the worm wheel 32, and a force is applied to the worm gear 31 in the axial direction of the rotary shaft 23 of the motor. Therefore, the worm gear 31 tends to move in the axial direction with respect to the rotating shaft 23, but the worm gear 31
Is supported between the inner walls 131 of the base 11 (transmission mechanism case portion 13) while being in contact with the stoppers 133 on both end surfaces, the force applied to the worm gear 31 is supported by the stoppers 133 and the inner wall 131. , Its axis movement is prevented. As a result, the worm gear 31 can be prevented from being axially moved with respect to the rotary shaft 23, the relative axial position between the worm gear 31 and the rotary shaft 23 is ensured, and accurate position movement of the windshield can be obtained. .

In this embodiment, the base 11 is
Since it is formed by die casting of aluminum or the like, the base 11 is hardly deformed or damaged even when the axial force applied to the worm gear 31 is received by the inner wall 131 thereof via the stopper 133. . Therefore, the axial force applied to the worm gear 31 is not transmitted to the rotary shaft 23, and the bearings 25a and 25c at both ends for axially supporting the rotary shaft 23 are not damaged by the excessive force. . This ensures smooth rotation of the rotary shaft 23. Further, since the base 11 is made of metal, the positional accuracy and dimensional accuracy in the armature 2, which can be said to be the heart of the motor, can be made extremely high as compared with a resin base or a base formed by pressing a metal plate. This is effective in improving motor characteristics, especially motor noise.

On the other hand, the case cover 12 which covers the base 11 is made of a hard resin, but since the seal portion 15 made of a soft resin is present at the portion in contact with the base 11, the case cover 12 is formed. Cover 12 base 1
1 and is fastened with the bolts 17, the seal portion 15 is brought into contact with the opening of the base 11 and the case cover 1
It is possible to secure the waterproofness of the motor case 1 by bringing the contact surface between the base 2 and the base 2 into close contact with each other. Since the case cover 12 can be manufactured by so-called two-color molding using a hard resin and a soft resin, a sealing material formed separately from the case cover is used between the case cover and the base as in the conventional case. The base and the case cover can be easily manufactured and the assembly thereof can be facilitated as compared with the structure in which the base and the case cover are waterproofed by inserting and supporting them.

Further, by providing abutting portions 15a to 15c on a part of the seal portion 15 made of a soft resin, and forming the abutting portions corresponding to the bearings 25a to 25c, the bearings 25a to 25c are formed as a base. When sandwiched between 11 and the case cover 12, the elastic force of the soft resin is used to make the bearing 2
5a to 25c are pressed to the base 11 side, and the bearings 25a to
It is also possible to prevent rattling in 25c, hold it stably, and hold the shaft center position of the rotary shaft 23 with high accuracy.

[0025]

As described above, according to the present invention, the motor case has the stopper for restricting the axial movement of the worm in contact with both axial end faces of the worm gear fitted and attached to the motor rotating shaft. Since it is arranged and supported, even when an external load is applied to the worm gear via the worm wheel and an axial force is applied to the worm gear, the worm gear is prevented from moving in the axial direction with respect to the rotating shaft. To be done. As a result, it is possible to prevent the position of the worm gear on the rotation axis from changing, and to prevent relative displacement between the motor rotation position and the load-side drive position in the motor drive device including the speed change mechanism. There is an effect that a high motor drive device can be configured.

[Brief description of drawings]

FIG. 1 is an external perspective view of an embodiment of a motor of the present invention.

FIG. 2 is a partially exploded perspective view of FIG.

FIG. 3 is a horizontal sectional view taken along the line AA in FIG.

FIG. 4 is a vertical sectional view taken along the line BB of FIG.

FIG. 5 is a plan view of the back surface of the case cover and an enlarged sectional view taken along the line DD thereof.

FIG. 6 is a partially exploded perspective view of a worm gear support structure.

7 is a vertical sectional view taken along the line CC of FIG.

[Explanation of symbols]

 1 Motor Case 2 Amateur 3 Transmission Mechanism 11 Base 12 Case Cover 13 Transmission Mechanism Case Part 14 Pulley Cover 15 Seal Part (Soft Resin) 23 Rotating Shaft 25 Bearing 31 Worm Gear 32 Worm Wheel 34 Pulley 35 Damper 36 Spline Rotating Body 37 Wire 131 Inner Wall 132 groove 133 stopper

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fusao Fukasawa 500 Kitawaki, Shimizu City, Shizuoka Prefecture Koito Manufacturing Co., Ltd. Shizuoka Factory

Claims (5)

[Claims] 1. A worm gear meshed with a worm wheel for constituting a speed change mechanism is fitted and attached to a rotary shaft of an electric motor housed in the motor case, and the worm gear is housed in the motor case. In the electric motor with a speed change mechanism, stoppers for contacting both axial end surfaces of the worm gear and restricting axial movement of the worm are provided at opposing inner wall portions of the motor case facing both axial end surfaces of the worm gear. An electric motor with a speed change mechanism, which is arranged and supported respectively. 2. The motor case includes a base and a case cover, which are divided into two parts in a plane parallel to the plane including the axis of the rotary shaft of the electric motor, and the base is die-cast by aluminum or aluminum alloy. And the case cover is formed by resin molding,
The electric motor with a speed change mechanism according to claim 1, wherein the stopper is disposed and supported on the base. 3. The electric motor with a speed change mechanism according to claim 2, wherein the case cover is made of a hard resin, and a seal portion made of a soft resin is formed on a contact surface with the base. 4. The electric motor with a speed change mechanism according to claim 3, wherein a part of the seal portion is formed as an abutting portion that abuts on a bearing portion of the rotary shaft. 5. The electric motor with a speed change mechanism according to claim 1, wherein the rotary shaft is arranged at three positions, that is, both end portions of the rotary shaft and a substantially central portion in the axial direction thereof.