JP2016021791A - Motor with reduction gear - Google Patents

Abstract

The present invention contributes to efficiently supporting an output shaft.
In a wiper motor, an output shaft that protrudes toward one axial direction of a worm wheel is supported by an output shaft support portion of a gear housing via a pair of ball bearings. Since the allowable bearing pressure of the ball bearing is larger than that of the slide bearing, the distance L between the pair of ball bearings 58 and 60 in the axial direction of the output shaft 26 is set shorter than the distance between the bearings of the conventional pair of slide bearings. It becomes possible to do. Thereby, for example, even when the dimension of the output shaft support portion 16A is restricted due to the relationship with the peripheral members in the mounted state on the vehicle, the output shaft 26 is efficiently supported within the range of the restricted dimension. It contributes to that.
[Selection] Figure 4

Description

  The present invention relates to a motor with a reduction gear applied to a wiper device for wiping a windshield glass of a vehicle.

  In the wiper motor described in Patent Document 1 below, an output shaft is coaxially fixed to a worm wheel housed in a gear housing, and the worm wheel and the output shaft are rotated together by the rotational force of the motor. The output shaft protrudes to one side in the axial direction of the worm wheel, and a magnetic sensor and a sensor magnet for detecting the rotational position of the output shaft are arranged on the other side in the axial direction of the worm wheel. The gear housing is formed with a cylindrical output shaft support portion protruding toward one side in the axial direction, and the output shaft is inserted into the output shaft support portion. In the output shaft support portion, a pair of slide bearings are mounted apart from each other in the axial direction, and the output shaft is rotatably supported by these slide bearings. In addition, Patent Document 2 below describes a wiper motor similar to the above.

JP 2014-42431 A JP 2014-50309 A

  In the wiper motor as described above, the size of the output shaft support portion may be restricted due to the relationship with the peripheral members when mounted on the vehicle. In such a case, it is required to efficiently support the output shaft within a limited size range.

  In view of the above facts, an object of the present invention is to obtain a motor with a reduction gear that contributes to efficiently supporting an output shaft.

  A motor with a reduction gear according to the present invention includes a worm wheel that is rotated by transmission of a rotational force of a motor body, and an output shaft that protrudes to one side in the axial direction of the worm wheel and is coaxially attached to the worm wheel. A gear housing in which the worm wheel is housed inside, and a cylindrical output shaft support portion into which the output shaft is inserted and cantilevered is protruded toward the one side in the axial direction, and the shaft A pair of ball bearings that are mounted in the output shaft support portion in a line and that rotatably support the output shaft.

  According to the motor with a speed reducer having the above-described configuration, the output shaft that protrudes toward the one side in the axial direction of the worm wheel is cantilevered on the output shaft support portion of the gear housing via the pair of ball bearings. Since the allowable bearing pressure of the ball bearing is larger than that of the slide bearing, the distance between the bearings of the pair of ball bearings can be set shorter than the distance between the bearings of the pair of conventional slide bearings. Thereby, it contributes to supporting an output shaft efficiently.

  Further, in the motor with a reduction gear according to the present invention, in addition to the above configuration, the output shaft support portion has a step portion between a large diameter portion provided on the proximal end side and a small diameter portion provided on the distal end side. A stepped shape is formed, and the pair of ball bearings are mounted in the large diameter portion.

  According to the motor with a reduction gear configured as described above, the pair of ball bearings are attached in the large diameter portion provided on the base end side of the output shaft support portion of the gear housing. Thereby, the dimension of the small diameter part provided in the front end side of the output-shaft support part can be set irrespective of a pair of ball bearings.

  Furthermore, in the motor with a reduction gear according to the present invention, in addition to the above configuration, the pair of ball bearings are inserted into the output shaft support portion from an opening on the base end side of the output shaft support portion, and the output shaft An abutting portion that abuts against one of the ball bearings from the distal end side of the output shaft supporting portion is provided on the inner peripheral portion of the supporting portion.

  According to the speed reducer-equipped motor configured as described above, a pair of ball bearings are inserted into the output shaft support portion from the proximal end side opening in the output shaft support portion of the gear housing. For this reason, workability | operativity can be improved compared with the case where a ball bearing is each inserted in an output-shaft support part from the opening of the front end side and proximal end in an output-shaft support part. In addition, an abutting portion that abuts against one ball bearing from the tip end side of the output shaft support portion is provided on the inner peripheral portion of the output shaft support portion. Accordingly, the one ball bearing on the distal end side of the pair of ball bearings arranged side by side in the axial direction can be easily positioned in the axial direction in the output shaft support portion deep in the gear housing.

  Furthermore, in addition to the above configuration, the motor with a reduction gear according to the present invention includes a seal member that seals between the tip of the output shaft support portion and the output shaft.

  According to the motor with a speed reducer having the above-described configuration, the gap between the output shaft support portion of the gear housing and the output shaft is sealed by the seal member, so that intrusion of rainwater or the like into the gear housing can be prevented. Thereby, it contributes to improving the freedom degree of arrangement | positioning with respect to the vehicle etc. of this motor with a reduction gear.

  In addition to the above-described configuration, the motor with a reduction gear according to the present invention is provided with a wiper arm fixing portion to which a wiper arm of a vehicle wiper device is fixed at a tip portion of the output shaft.

  In the motor with a reduction gear configured as described above, the load from the wiper arm is directly input to the output shaft. In such a wiper motor, a high load resistance is required for the bearing that supports the output shaft. However, in the present invention, a good load resistance can be ensured by the pair of ball bearings.

It is a perspective view of the wiper motor concerning one embodiment of the present invention. It is a bottom view of the wiper motor. It is sectional drawing which shows the cut surface along the F3-F3 line | wire of FIG. It is sectional drawing which shows the cut surface along the F4-F4 line | wire of FIG.

  A wiper motor 10 according to an embodiment to which the motor with a speed reducer of the present invention is applied will be described below with reference to FIGS. First, the overall configuration of the wiper motor 10 will be described, and then the main part of the present embodiment will be described.

(Overall configuration of wiper motor 10)
The wiper motor 10 according to the present embodiment is a drive source for a vehicle wiper device, and includes a motor body 12 and a gear housing 14 that constitutes a speed reduction unit, as shown in FIGS. The gear housing 14 is formed in a box shape by a metal housing main body 16 and a resin housing cover 18 attached to the housing main body 16.

  The motor body 12 is attached to the side of the housing body 16, and the armature shaft 20 extends into the gear housing 14. A bearing portion 22 that pivotally supports the tip of the armature shaft 20 is provided at the end of the housing body 16 opposite to the motor body 12. A worm gear 20A is formed by means such as rolling at a portion of the armature shaft 20 located in the gear housing 14. A worm wheel 24 accommodated in the gear housing 14 is engaged with the worm gear 20A. The motor body 12 is driven and controlled so as to be rotatable forward and backward by a control circuit configured on a circuit board 38 accommodated in the gear housing 14.

  Here, the worm wheel 24 is made of resin, and a cylindrical boss portion 24A is coaxially formed at the center thereof. A metal output shaft 26 is fixed to the boss portion 24A. The output shaft 26 protrudes from the worm wheel 24 to one side in the axial direction (the upper side in FIGS. 3 and 4), and at the base end portion opposite to the protruding direction, the boss portion 24A It is fixed coaxially. As a result, the output shaft 26 can rotate coaxially and integrally with the worm wheel 24.

  The output shaft 26 is insert-molded when the worm wheel 24 is molded, and a base end portion embedded in the worm wheel 24 is provided with a reduced diameter portion 26A having a reduced shaft diameter. A pair of fixing plates 28 for increasing the fixing strength of the output shaft 26 with respect to the worm wheel 24 are attached to the reduced diameter portion 26 </ b> A at intervals in the axial direction of the output shaft 26. These fixing plates 28 are embedded in the worm wheel 24 by performing the above-described insert molding after being press-fitted and fixed to the reduced diameter portion 26A.

  On the other hand, the housing body 16 is formed with an output shaft support portion 16A corresponding to the output shaft 26 described above. The output shaft support portion 16 </ b> A is formed in a cylindrical shape coaxial with the output shaft 26 and the worm wheel 24, and protrudes integrally from the bottom of the housing body 16 toward one axial direction of the worm wheel 24. The output shaft 26 is inserted inside the output shaft support portion 16A, and is rotatably supported by a pair of ball bearings 58 and 60 described later with respect to the output shaft support portion 16A.

  The distal end portion of the output shaft 26 protrudes to the outside of the gear housing 14 from the opening 30 on the distal end side of the output shaft support portion 16A, and a tea washer 32 is fastened to the protruding portion. The output shaft 26 is prevented from being pulled out by the tea washer 32.

  The worm wheel 24 fixed to the base end portion of the output shaft 26 is meshed with the worm gear 20A formed on the armature shaft 20 of the motor body 12 as described above. For this reason, when the motor body 12 is actuated to rotate the armature shaft 20, this rotational force is transmitted to the worm wheel 24 via the worm gear 20 </ b> A, and the worm wheel 24 rotates integrally with the output shaft 26.

  A wiper arm fixing portion 26B to which a base end portion 34A (see a two-dot chain line in FIG. 4) of a wiper arm 34 that is a constituent member of the vehicle wiper device is directly fixed is provided at the distal end portion of the output shaft 26. Further, around the output shaft support portion 16 </ b> A in the housing body 16, a plurality of (three in this case) vehicle body side fixing portions 16 </ b> B are provided at rotationally symmetric positions with the axis of the output shaft 26 as a symmetric point. These vehicle body side fixing portions 16 </ b> B protrude from the housing body 16 toward the one side in the axial direction of the output shaft 26 in a columnar shape. These vehicle body side fixing portions 16B are formed with female thread portions that open toward one axial side of the output shaft 26 (the upper side in FIGS. 3 and 4). The wiper motor 10 is fixed to a bracket 36 (see a two-dot chain line in FIG. 4) using male screw members such as bolts screwed into these female screw portions, and the bracket 36 is fixed to a cowl top or the like of the vehicle.

  Then, when the wiper arm 34 fixed to the wiper arm fixing portion 26B is rotated integrally with the output shaft 26, the wiper blade provided on the distal end side of the wiper arm 34 is windshield glass of the vehicle (both not shown). ) The wiper arm 34 is not limited to being directly fixed to the output shaft 26, but may be configured to be indirectly connected to the output shaft 26 via a link mechanism, a pivot shaft, or the like.

  On the other hand, as shown in FIGS. 3 and 4, a circuit board 38 is disposed on the other side in the axial direction of the worm wheel 24 in the gear housing 14. The circuit board 38 is disposed with the thickness direction along the axial direction of the worm wheel 24 and spaced from the worm wheel 24, and is fixed to the inner surface side of the housing cover 18 by means such as screws. Has been. A magnetic sensor 40 is mounted on the circuit board 38. The magnetic sensor 40 is disposed coaxially with the axis of the output shaft 26 at a portion facing the other axial side surface (the lower surface in FIGS. 3 and 4) of the boss portion 24A. A sensor magnet 42 is attached to the boss 24 </ b> A corresponding to the magnetic sensor 40.

  The sensor magnet 42 is a resin magnet formed, for example, by mixing magnetic powder and a binder made of synthetic resin or the like and molding the molded product. The sensor magnet 42 is formed in a substantially disk shape having a slightly smaller diameter than the boss portion 24A, and one half of the radial direction is an N pole and the other half of the radial direction is an S pole.

  The sensor magnet 42 is disposed coaxially with the axis of the output shaft 26 and is in contact with the other axial side surface of the boss portion 24A. A plurality of holding pieces 46 extending to the other axial side of the worm wheel 24 (the lower side in FIGS. 3 and 4) are formed on the outer peripheral portion of the boss portion 24A. These holding pieces 46 are formed in a plate shape concentrically curved with the boss portion 24A, and are arranged in the circumferential direction of the boss portion 24A so as to surround the sensor magnet 42 from the radially outer side. These holding pieces 46 abut on the outer peripheral surface of the sensor magnet 42, whereby the sensor magnet 42 is held in the radial direction with respect to the worm wheel 24.

  Further, at least two or more holding pieces 46 among the plurality of holding pieces 46 are formed with claw portions 46A protruding from the tip portion to the inside in the radial direction of the boss portion 24A. These claw portions 46A engage with the other axial side surface (the lower surface in FIGS. 3 and 4) of the sensor magnet 42, whereby the sensor magnet 42 is held in the axial direction with respect to the worm wheel 24. .

  Further, of the plurality of holding pieces 46, the pair of holding pieces 46 that face each other in the radial direction of the worm wheel 24 have protrusions that fit into grooves formed on the outer peripheral surface of the sensor magnet 42 (none of which are shown). Is formed. Thereby, the sensor magnet 42 is positioned in the circumferential direction with respect to the worm wheel 24. The sensor magnet 42 faces the magnetic sensor 40 described above in proximity to the axial direction of the worm wheel 24.

  The magnetic sensor 40 has a configuration in which the electric resistance value changes according to the direction and magnitude (strength) of magnetic flux from the north pole to the south pole of the sensor magnet 42, the magnetic flux density, and the like. The output of the magnetic sensor 40 changes according to the position. Based on the output signal of the magnetic sensor 40, a control means such as an ECU detects the rotational position of the sensor magnet 42.

  The rotational position of the sensor magnet 42 corresponds to the rotational position of the worm wheel 24 and the output shaft 26, that is, the rotational position of the wiper arm 34. For this reason, based on the output signal of the magnetic sensor 40, the control means determines in which direction of the wiping range in the windshield glass is moved and in which angular position. Based on the determination result, the control means controls the magnitude of the voltage supplied to the motor main body 12 and the direction of the current to drive the motor main body 12 in the forward or reverse direction. Thereby, the wiper arm 34 is reciprocally rotated within the wiping range. The above is the overall configuration of the wiper motor 10 according to the present embodiment. Hereinafter, the main part of this embodiment will be described.

(Main part of this embodiment)
In the present embodiment, the output shaft support portion 16A of the gear housing 14 is formed in a stepped cylindrical shape. The output shaft support portion 16 </ b> A has a large diameter portion 48 on the proximal end side and a small diameter portion 50 on the distal end side. The large diameter portion 48 has an inner diameter and an outer diameter larger than the small diameter portion 50. And between the small diameter part 50 and the large diameter part 48, the step parts 54 and 56 are formed in the inner peripheral part and outer peripheral part of 16 A of output-shaft support parts, respectively.

  As shown in FIG. 4, the protruding height H <b> 1 of the large diameter portion 48 from the housing body 16 is slightly higher than the protruding height H <b> 2 of the vehicle body side fixing portion 16 </ b> B from the housing body 16. A pair of ball bearings 58 and 60 that are radial bearings are coaxially arranged in the axial direction inside the large diameter portion 48, and the output shaft 26 can be rotated by these ball bearings 58 and 60. It is supported. These ball bearings 58 and 60 are inserted (press-fitted) into the large-diameter portion 48 from the opening 31 on the proximal end side of the output shaft support portion 16A, and are slightly spaced in the axial direction of the output shaft 26. Are lined up.

  Of these ball bearings 58, 60, one ball bearing 58 located on the back side (tip side of the output shaft support portion 16 </ b> A) as viewed from the opening 31 side (worm wheel 26 side) is the outer peripheral portion of the step portion 54. The end surface of the outer ring is in contact with the contact portion 54A formed on the outer periphery. Thus, the ball bearing 58 is positioned in the axial direction with respect to the output shaft support portion 16A. The contact portion 54A protrudes from the inner peripheral side of the step portion 54 toward the proximal end side of the output shaft support portion 16A, so that the inner ring of the ball bearing 58 does not come into contact with the step portion 54.

  Between the outer ring of the ball bearing 58 and the outer ring of the other ball bearing 60, a ring-shaped spacer (not shown) is interposed (sandwiched). Thus, the other ball bearing 60 is positioned in the axial direction with respect to the output shaft support portion 16A. The ball bearing 60 is arranged so that the end surface on the worm wheel 24 side is located on the same plane as the base end surface 62 of the output shaft support portion 16A. A wave washer (not shown) is interposed between the end face of the ball bearing 60 and the end face of the boss portion on the ball bearing 60 side.

  Further, a seal mounting portion 64 is formed in a recessed manner at the edge of the opening 30 on the distal end side of the output shaft support portion 16A. The seal mounting portion 64 is formed by expanding the inner diameter of the small diameter portion 50 in a stepped manner at the edge of the opening 30. An O-ring 68 serving as a seal member is fitted into the seal mounting portion 64 and is prevented from jumping out from the seal mounting portion 64 by the tea washer 32. The tip of the output shaft support portion 16A is prevented by the O-ring 68. The portion and the output shaft 26 are sealed.

(Function and effect)
Next, the operation and effect of this embodiment will be described.

  In the wiper motor 10 having the above-described configuration, the output shaft 26 protruding to one axial direction of the worm wheel 24 is cantilevered by the output shaft support portion 16A of the gear housing 14 via a pair of ball bearings 58 and 60. Since the ball bearing has a larger allowable surface pressure than the plain bearing, the distance L between the pair of ball bearings 58, 60 (the distance between the axial center of the ball bearing 58 and the axial center of the ball bearing 60: FIG. 4) can be set shorter than the distance between the bearings of a pair of conventional slide bearings. Thereby, for example, even when the dimension of the output shaft support portion 16A is restricted due to the relationship with the peripheral members in the mounted state on the vehicle, the output shaft 26 is efficiently supported within the range of the restricted dimension. It contributes to that.

  In addition, in this embodiment, the output shaft support portion 16A has a stepped portion in which step portions 54 and 56 are formed between the large diameter portion 48 provided on the proximal end side and the small diameter portion 50 provided on the distal end side. The pair of ball bearings 58, 60 are mounted in the large diameter portion 48. That is, since the pair of ball bearings 58 and 60 is provided only on the base end side (worm wheel 24 side) of the output shaft support portion 16A, the outer side of the small diameter portion 50 provided on the distal end side of the output shaft support portion 16A. The diameter and height can be set independently of the pair of ball bearings 58 and 60. Thereby, the arrangement space of the small diameter portion 50 in the vehicle can be reduced. For example, when the wiper arm 34 is fixed directly to the output shaft 26, the base end portion 34 </ b> A of the wiper arm 34 is in a state where the wiper arm 34 is fixed to the output shaft 26 in order to prevent water from entering from the output shaft portion of the wiper motor 10. A cylindrical peripheral wall extending around the tip of the output shaft support 16A is formed. The tip of the output shaft support 16A is a small diameter portion 50, so that the base of the wiper arm 34 is formed. Not only can the end portion 34A be reduced in size, but also contributes to improving the degree of freedom of arrangement of other components of the vehicle provided around the small diameter portion 50.

  Further, when the wiper motor 10 is manufactured, the pair of ball bearings 58 and 60 are inserted into the output shaft support portion 16A from the opening 31 on the proximal end side of the output shaft support portion 16A of the gear housing 14. For this reason, workability is improved as compared with the case where the ball bearings 58 and 60 are respectively inserted into the output shaft support portion 16A from the opening 30 on the distal end side and the opening 31 on the proximal end side in the output shaft support portion 16A. be able to.

  Moreover, the inner peripheral portion of the output shaft support portion 16A abuts from one end of the output shaft support portion 16A against one ball bearing 58 positioned on the back side when viewed from the opening 31 side (worm wheel 24 side). A contact portion 54A is provided. Thereby, one ball bearing 58 on the front end side of the pair of ball bearings arranged side by side in the axial direction can be easily positioned in the axial direction in the output shaft support portion 16 </ b> A deep in the gear housing 14.

  Furthermore, in this embodiment, since the gap between the output shaft support portion 16A of the gear housing 14 and the output shaft 26 is sealed by the O-ring 68, it is possible to prevent rainwater or the like from entering the gear housing 14. As a result, the wiper motor 10 can be disposed (installed) in a region where rainwater or the like is applied in the vehicle, which contributes to an improvement in the degree of freedom of the arrangement of the wiper motor 10 with respect to the vehicle.

  In the present embodiment, a wiper arm fixing portion 26B to which the wiper arm 34 of the vehicle wiper device is fixed is provided at the distal end portion of the output shaft 26. In such a wiper motor 10, since the load from the wiper arm 34 is directly input to the output shaft 26, a high load resistance is required for the bearing that supports the output shaft 26. The ball bearings 58 and 60 can ensure good load resistance.

  In the above embodiment, the O-ring 68 (seal member) that seals between the tip of the output shaft support portion 16A and the output shaft 26 is provided. However, the present invention is not limited thereto, and the seal member is not limited thereto. The configuration may be omitted. The seal member may be any member that can prevent water and the like from entering the gear housing, and may be other than an O-ring.

  In the above embodiment, the pair of ball bearings 58 and 60 are inserted into the output shaft support portion 16A from the opening 31 on the proximal end side of the output shaft support portion 16A. However, the present invention is not limited thereto. It is not a thing. That is, one ball bearing 58 is inserted into the output shaft support portion 16A from the opening 30 on the distal end side of the output shaft support portion 16A, and the other ball bearing 60 is the opening 31 on the proximal end side of the output shaft support portion 16A. To the output shaft support portion 16A.

  Furthermore, in the said embodiment, although the contact part 54A provided in the inner peripheral part of 16 A of output-shafts was set as the structure contacted with respect to one ball bearing 58 from the front end side of 16 A of output-shaft support parts. The present invention is not limited to this, and the contact portion 54A and the stepped portion 54 may be omitted.

  Further, in the above embodiment, the output shaft support portion 16A is formed in a stepped cylindrical shape in which step portions 54 and 56 are formed between the large diameter portion 48 on the proximal end side and the small diameter portion 50 on the distal end side. However, the present invention is not limited to this, and the shape of the output shaft support portion 16A can be changed as appropriate.

  In the above-described embodiment, a so-called “bond magnet” in which a ferromagnetic powder and a binder made of a synthetic resin material are mixed and molded is applied as the sensor magnet 42. However, the present invention is not limited to this, and the magnetic magnet is not limited thereto. A sensor magnet formed by sintering a material may be used.

  Furthermore, although the said embodiment demonstrated the case where the thing using a magnetoresistive element was applied as the magnetic sensor 40, the structure of a magnetic sensor can be changed suitably. For example, a magnetic sensor using a Hall element may be used.

  Moreover, in the said embodiment, although applied to the wiper motor 10 as a drive source of a wiper apparatus as a motor with a reduction gear, it applies to the motor with a reduction gear for vehicles which drives a sunroof, a sliding door, a power window, etc. of a vehicle. Also good.

  In addition, the present invention can be implemented with various modifications without departing from the scope of the invention. It goes without saying that the scope of rights of the present invention is not limited to the above embodiment.

  DESCRIPTION OF SYMBOLS 10 ... Wiper motor (motor with reduction gear), 12 ... Motor main body, 14 ... Gear housing, 16A ... Output shaft support part, 24 ... Worm wheel, 26 ... Output shaft, 26B ... Wiper arm fixing part, 31 ... Opening on the base end side of the output shaft support part, 48 ... Large diameter part, 50 ... Small diameter part, 54, 56 ... Step part, 54A ... Contact part, 58, 60 ... ball bearing, 68 ... O-ring (seal member)

Claims (5)

A worm wheel that is rotated by the rotational force of the motor body, and
An output shaft that projects to one side in the axial direction of the worm wheel and is coaxially attached to the worm wheel;
A gear housing that accommodates the worm wheel on the inside, and has a cylindrical output shaft support portion that is cantilevered and inserted through the output shaft, and projects toward the one side in the axial direction.
A pair of ball bearings mounted in the output shaft support portion side by side in the axial direction and rotatably supporting the output shaft;
A motor with a reduction gear.   The output shaft support portion has a stepped shape in which a step portion is formed between a large diameter portion provided on the proximal end side and a small diameter portion provided on the distal end side, and the pair of ball bearings The motor with a speed reducer according to claim 1, wherein the motor is attached in the large diameter portion.   The pair of ball bearings are inserted into the output shaft support portion from an opening on the proximal end side of the output shaft support portion, and the inner peripheral portion of the output shaft support portion is provided with respect to one of the ball bearings. The motor with a speed reducer according to claim 1, wherein a contact portion that is in contact with the front end side of the output shaft support portion is provided.   The motor with a reduction gear according to any one of claims 1 to 3, further comprising a seal member that seals a gap between a distal end portion of the output shaft support portion and the output shaft.   The motor with a reduction gear according to any one of claims 1 to 4, wherein a wiper arm fixing portion to which a wiper arm of a vehicle wiper device is fixed is provided at a distal end portion of the output shaft.

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