JP2009213278A - Electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate assembling work of a rotary shaft. <P>SOLUTION: In a wiper motor 11 equipped with a motor yoke 12a, a gear case 16 coupled to the motor yoke 12a, the rotary shaft 12b inserted into the motor yoke 12a, a ball bearing 35 rotatably supporting the intermediate portion of the rotary shaft 12b, and a ball bearing holding part 36 provided to the gear case 16 for holding the ball bearing 35, a ball bearing pressing member 38 is fitted in the vicinity of the ball bearing holding part 36 of the gear case 16 from the side of the rotary shaft 12b. The ball bearing pressing member 38 presses the ball bearing holding portion 36 with reaction portions 38b, 38c urged by the reaction force of the gear case 16, and with the elastic force of an acting portion 38a. With the ball bearing 35 being restricted in position beforehand by a stop ring 34 fitted into the circular groove 33 formed in the rotary shaft 12b, the rotary shaft 12b is assembled to the gear case 16 to secure the ball bearing 35 with the ball bearing pressing member 38. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an electric motor.
For example, the present invention relates to an effective device for use in a wiper motor of a vehicle wiper device.

As a drive source for a vehicle wiper device, a wiper motor which is an example of an electric motor with a speed reduction mechanism is often used.
An example of a conventional wiper motor is disclosed in Patent Document 1.
That is, the wiper motor includes an electric motor, a speed reduction mechanism that decelerates the rotation of the rotating shaft of the electric motor and outputs it to the output shaft, and a bottomed casing (gear case) that is connected to the electric motor and accommodates the speed reduction mechanism. A ball bearing (ball bearing) fixed to the rotating shaft and held in the casing; a holder base having a brush (brush holder stay); and a holder base mounting member for attaching the holder base to the casing. The mounting member is screwed to the casing, and the ball bearing is fixed to the casing.

Japanese Utility Model Publication No. 6-15491

In the wiper motor described above, when the ball bearing fixed to the rotating shaft is screwed to the casing by the holder base mounting member, the holder base mounting member needs to be incorporated into the rotating shaft first.
Further, since the holder base mounting member is expected to be larger than the inner diameter of the holder base, the holder base needs to be assembled to the rotating shaft first.
As a result, when the rotating shaft is assembled to the casing, the holder base mounting member and the holder base are in a state of floating around the rotating shaft, so that the assembling work becomes difficult.

  The objective of this invention is providing the electric motor which can improve the assembly | attachment operation | work of a rotating shaft.

Typical means for solving the above-described problems are as follows.
(1) a motor yoke;
A case connected to the motor yoke;
A rotating shaft inserted into the motor yoke;
A ball bearing for rotatably supporting the rotating shaft;
A ball bearing holding portion provided in the case for holding the ball bearing;
An electric motor comprising:
A ball bearing holding member is attached from the side of the rotating shaft in the vicinity of the ball bearing holding portion of the case,
An electric motor characterized in that the ball bearing is pressed against the ball bearing holding portion by an axial elastic force of the ball bearing pressing member.
(2) The ball bearing pressing member is formed continuously between a pair of reaction force portions for applying a reaction force to the case and the reaction force portion, and holds the ball bearing by the elastic force. The electric motor according to (1), characterized in that the electric motor comprises an action portion that presses against the portion.
(3) The electric motor according to (1) or (2), wherein an annular groove is formed in the rotating shaft, and the position of the ball bearing is regulated by a stop ring fitted in the annular groove. .

  According to said (1), the assembly | attachment operation | work of a rotating shaft can be improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In the present embodiment, the electric motor according to the present invention is configured as a wiper motor of a vehicle wiper device.

  As shown in FIG. 1, the wiper motor 11 is a motor with a speed reduction mechanism in which a speed reducer 13 is fixed to a motor body 12 that is an electric motor to form a single unit. Used as a drive source for the device.

  The motor body 12 is configured as a so-called brushed DC motor. The motor body 12 includes a motor yoke 12a formed of a steel plate in a cylindrical shape with a bottom, and a rotating shaft 12b rotatably supported by the motor yoke 12a, and a direct current supplied from a battery (power source) (not shown). The rotary shaft 12b is rotated by the operation.

On the other hand, the speed reducer 13 includes a gear box 14, and a speed reduction mechanism 15 is accommodated in the gear box 14.
The gear box 14 includes a gear case 16 as a box body and a gear cover 17 as a lid for closing the gear case 16, and the gear box 14 is configured by combining these.
As shown in FIG. 2, the gear case 16 is formed in a bathtub shape from an aluminum alloy, and is fixed to the motor yoke 12a on one side thereof.

As shown in FIG. 2, the rotating shaft 12b of the motor body 12 protrudes from the motor yoke 12a and is rotatably accommodated in the gear case 16, that is, the gear box 14, and is accommodated in the gear box 14 of the rotating shaft 12b. A worm 15a is integrally formed on the outer peripheral surface of the portion.
When the motor main body 12 is operated, the worm 15a rotates together with the rotating shaft 12b.
A worm wheel 15b fixed to the output shaft 18 is rotatably accommodated in the gear case 16, and the worm wheel 15b and the worm 15a are engaged with each other. It is configured.
As a result, when the motor body 12 is actuated to rotate the rotating shaft 12b, the rotation is decelerated to a predetermined number of rotations by the decelerating mechanism 15 and output from the output shaft 18.

The gear cover 17 is formed in a lid shape using a resin material, and is combined with the opening of the gear case 16 to close the gear case 16.
As shown in FIG. 1, the gear cover 17 is provided with a heat sink 21 made of aluminum alloy having a plurality of fins, and approximately half of the outer surface portion of the gear cover 17 is occupied by the heat sink 21.

Although not shown, a control board is fixed to the back surface of the gear cover 17 so as to face the heat sink 21. The control board is a so-called mother board having a microcomputer function as a plurality of electronic components such as a CPU, a memory, and an FET mounted on a printed wiring board.
The control board is fixed to the gear cover 17 so as to be accommodated in the gear box 14 and fixed.
The control board is connected to the motor main body 12 by a power supply line (not shown) and connected to a wiper switch (not shown) or a battery (power supply) (not shown) via a connector 23 (see FIG. 1) provided on the gear cover 17 by a power supply line (not shown). It is connected. The control board supplies a direct current to the motor main body 12 in accordance with a command signal from the wiper switch to perform operation control.

  As shown in FIG. 1, three fixing portions 24 are provided at a predetermined interval in a combination portion of the gear case 16 and the gear cover 17. Clips 25 as fastening members are respectively attached to these fixing portions 24, and a fastening force is applied from these clips 25 to the fixing portion 24, so that the gear case 16 and the gear cover 17 are fixed to each other. ing.

As shown in FIG. 2, a pair of arc-shaped field magnets 26 are fixed to be opposed to the inner peripheral surface of the motor yoke 12a.
An end bearing 27 is housed in the bottom of the motor yoke 12a and is fixed by an end bearing retainer 28. One end of the rotary shaft 12b is inserted into the end bearing 27. The end bearing 27 supports one end of the rotary shaft 12b so as to be rotatable.

An armature core 29 is fixed to the rotary shaft 12 b at a position facing the field magnet 26, and a commutator 30 is fixed at a position adjacent to the armature core 29.
In the gear case 16, a connecting portion 16 a is formed at a position facing the commutator 30. The connecting portion 16a is formed in a cylindrical shape in which one end surface including a cylindrical wall 16b and a closing wall 16c that closes one opening of the cylindrical wall 16b is closed.
A brush device 31 is installed in the connecting portion 16a, and the brush device 31 is in sliding contact with the commutator 30.
The opening portion of the motor yoke 12a is fitted to the connecting portion 16a, and the connecting portion 16a and the motor yoke 12a are connected by a bolt 32 screwed into a flange portion 16d projecting from the outer periphery of the connecting portion 16a. It is concluded.

Two annular grooves 33 are provided in the outer periphery of the rotary shaft 12b at a position between the commutator 30 and the worm 15a, and the stop rings 34 are respectively annular with the ball bearings 35 press-fitted into the rotary shaft 12b. Fit into the groove 33. Thereby, the movement of the rotating shaft 12b and the ball bearing 35 in the axial direction can be restricted.
The ball bearing (ball bearing) 35 is embedded in an outer ring portion 35a, an inner ring portion 35b that is positioned on the inner peripheral side of the outer ring portion 35a and into which the rotary shaft 12b is press-fitted, and a space between the outer ring portion 35a and the inner ring portion 35b. It is formed in a cylindrical shape composed of a plurality of arranged ball portions 35c (a part is shown). The position of the ball bearing 35 is regulated so that both end surfaces of the inner ring portion 35 b are in contact with the stop ring 34.

As shown in FIGS. 3 and 4, an insertion hole 16 e is formed in the central portion of the cylindrical wall 16 c of the connecting portion 16 a, and the inner diameter of the insertion hole 16 e is larger than the outer diameter of the ball bearing 35. It is formed as follows.
In the gear case 16, a ball bearing holding portion 36 for holding the ball bearing 35 is formed in the vicinity of the insertion hole 16 e in the bathtub-shaped bottom wall, and the ball bearing holding portion 36 has an inner diameter that is the outer ring portion of the ball bearing 35. It is formed in a substantially circular hole shape equal to the outer diameter of 35a.
As shown in FIG. 3, the gear case 16 has a pair of engagement holes 37, 37 formed in the vicinity of the outer portion of the ball bearing holding portion 36, and the pair of engagement holes 37, 37 are insertion holes. They are arranged symmetrically with respect to the center line 16e. One end portions of a pair of ball bearing pressing members 38, 38 are engaged with the pair of engaging holes 37, 37, respectively.

The pair of ball bearing pressing members 38, 38 are formed in the same shape.
That is, the ball bearing pressing member 38 is formed in a rectangular plate shape using a plate material having an elastic force, and includes an action portion 38a, a pair of reaction force portions 38b and 38c, a gripping portion 38d, and an engagement hole 38e. ing. The action portion 38a is bent in an arch shape in one direction of the plate thickness with respect to the pair of reaction force portions 38b and 38c. The grip portion 38d is formed by bending one reaction force portion 38c at a right angle, and is configured so that a jig (not shown) can be attached. The engaging hole 38e is formed at a substantially central portion of the gripping portion 38d, and is configured to be able to engage a protrusion (not shown) formed on the gear cover 17.

Next, the work of assembling the rotary shaft 12b and the ball bearing 35 to the gear case 16 and the work of fixing the ball bearing 35 by the pair of ball bearing pressing members 38, 38 will be described.
In advance, the inner ring portion 35b of the ball bearing 35 is fitted to the outer periphery of the rotary shaft 12b, and the position of both end surfaces of the inner ring portion 35b of the ball bearing 35 is restricted by the stop ring 34.
The rotating shaft 12b is inserted into the insertion hole 16e of the gear case 16 from the connecting portion 16a side with the worm 15a side first, and the outer ring portion 35a of the ball bearing 35 is fitted into the ball bearing holding portion 36.
Next, in a state where the gripping portion 38d is gripped by a jig (not shown), a pair of ball bearing pressing members 38, 38 are respectively inserted into adjacent positions of the ball bearing 35, and the respective reaction force portions 38b, 38b is inserted into the pair of engaging holes 37, 37, and the other reaction force portions 38c, 38c are engaged with the side surfaces of the cylindrical wall 16c of the connecting portion 16a.
Thereafter, the jig is removed from the pair of ball bearing pressing members 38, 38, respectively.
As described above, when the pair of ball bearing pressing members 38, 38 are respectively attached to the gear case 16, the pair of ball bearing pressing members 38, 38 press the ball bearing 35 against the ball bearing holding portion 36. The ball bearing 35 is fixed to the ball bearing holding portion 36.
That is, since both reaction force portions 38b and 38c of the ball bearing pressing member 38 take a reaction force on the gear case 16, the action portion 38a formed to protrude from both reaction force portions 38b and 38c is a ball bearing by an elastic force. When the outer ring portion 35a of 35 is pushed in the direction of the one stop ring 34, the ball bearing 35 can be pressed against the ball bearing holding portion 36 and fixed.

  After that, when the gear cover 17 is put on the gear case 16 and fixed, the pair of ball bearing pressing members 38, 38 are engaged with the projections (not shown) of the gear cover 17 in the respective engagement holes 38e, 38e. Therefore, the engagement holes 37 and 37 are prevented from coming off.

  According to the embodiment, the following effects can be obtained.

(1) When assembling the rotary shaft and the bearing into the gear case, the bearing is fitted on the outer periphery of the rotary shaft, and the position is regulated by a stop ring to prevent the bearing from floating around the rotary shaft. Therefore, it is possible to facilitate the assembly work.

(2) Since the ball bearing holding member is inserted into the engagement hole from the side of the rotary shaft and the ball bearing after the rotary shaft and the ball bearing are assembled to the gear case, the bearing can be fixed to the ball bearing holding portion. When assembling the rotary shaft and the ball bearing to the gear case, the inner peripheral surface of the inner ring portion of the ball bearing can be fitted in advance to the outer periphery of the rotary shaft and the position can be regulated by the stop ring.

(3) By forming the pair of ball bearing pressing members 38, 38 in the same shape, the number of component types and the number of processing steps can be reduced, so that the manufacturing cost can be reduced.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, the ball bearing holding member is not limited to a plurality of parts, but can be a single part.

  In the case where the position of the ball bearing can be regulated by press-fitting into the rotating shaft, the stop ring can be omitted.

  In the above-described embodiment, the case where the wiper motor is used has been described. However, the present invention is not limited to this, and an electric motor with a speed reduction mechanism such as a vehicle power window device or a sunroof device is not provided. It can be applied to all electric motors such as electric motors.

It is a perspective view which shows the wiper motor which is one embodiment of this invention. FIG. (A) is sectional drawing which follows the III-III line of FIG. 2, (b) is sectional drawing which follows the bb line of (a). It is a perspective view which shows the principal part.

Explanation of symbols

11 Wiper motor (electric motor)
12 Motor body 12a Motor yoke 12b Rotating shaft 13 Reducer 14 Gear box 15 Reduction mechanism 15a Worm 15b Worm wheel 16 Gear case 16a Connecting portion 16b Cylindrical wall 16c Closure wall 16e Insertion hole 17 Gear cover 18 Output shaft 27 End bearing 29 Armature 30 Commutator 31 Brush device 33 Annular groove 34 Stop ring 35 Ball bearing 35a Cylindrical wall 35b 鍔 36 Ball bearing holding part 37 Engaging hole 38 Ball bearing pressing member 38a Action part 38b, 38c Reaction force part 38d Gripping part 38e Engaging hole

Claims (3)

A motor yoke;
A case connected to the motor yoke;
A rotating shaft inserted into the motor yoke;
A ball bearing for rotatably supporting the rotating shaft;
A ball bearing holding portion provided in the case for holding the ball bearing;
An electric motor comprising:
A ball bearing holding member is attached from the side of the rotating shaft in the vicinity of the ball bearing holding portion of the case,
An electric motor characterized in that the ball bearing is pressed against the ball bearing holding portion by an axial elastic force of the ball bearing pressing member.   The ball bearing pressing member is formed continuously between a pair of reaction force portions for applying a reaction force to the case and the reaction force portion, and presses the ball bearing against the ball bearing holding portion by an elastic force. 2. The electric motor according to claim 1, wherein the electric motor comprises an action portion that performs the following.   The electric motor according to claim 1, wherein an annular groove is formed in the rotating shaft, and the position of the ball bearing is regulated by a stop ring fitted in the annular groove.

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