JP2017189110A - Motor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To not only reduce size, weight and a cost of a motor device, but also to enhance stop position accuracy.SOLUTION: Since a recess 33e for passing a second contact plate, as a worm wheel 32 rotates, is provided at a part of an outer periphery 33a of a switching plate 33, a rotation angle β° of the worm wheel 32 can be reduced for distance L1 (e.g., 3.0 mm), in which the second contact plate advances in the recess 33e by inertia, and thereby variation is less likely to occur in the stop position of the worm wheel 32 than conventional one. Consequently, not only size, weight and a cost of a rear wiper motor can be reduced, but also stop position accuracy of the worm wheel 32 can be enhanced.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a motor device including a motor unit having a rotation shaft and a speed reduction mechanism unit having a speed reduction mechanism that decelerates rotation of the rotation shaft.

  2. Description of the Related Art Conventionally, a motor device including a motor unit and a speed reduction mechanism unit is used as a drive source such as a wiper device mounted on a vehicle such as an automobile. The motor unit includes a rotating shaft that is rotated by supplying a drive current, and the speed reducing mechanism unit includes a speed reducing mechanism that decelerates the rotation of the rotating shaft. As described above, by providing the speed reduction mechanism, a large output can be obtained while being small, and as a result, the onboard performance of the motor device is improved. As a motor apparatus provided with such a motor part and a speed reduction mechanism part, the technique described in patent document 1, 2, for example is known.

  Each of the motor devices described in Patent Documents 1 and 2 is used as a drive source for the wiper device, and includes a speed reduction mechanism including a worm and a worm wheel. The worm wheel is formed in a disk shape, and an annular conductive plate is mounted on one surface of the worm wheel. And the protrusion part (convex part) which protruded to the radial direction outer side of the said conductive plate is provided in a part of outer peripheral part of the conductive plate. Further, a part of the inner peripheral portion of the conductive plate is provided with a notch (recessed portion) recessed outward in the radial direction of the conductive plate.

  Three contacts (contact points) for switching the energization state to the motor unit are in sliding contact with the conductive plate. The first contact is always in sliding contact with the conductive plate, the second contact passes through the notch, and the third contact passes through the protrusion. And if a wiper switch is turned off by a driver | operator, a 2nd contact will slidably contact a notch part with rotation of a worm wheel after that. As a result, the connection between the first contact and the second contact is disconnected, and the supply of the drive current to the motor unit is stopped. At this time, the worm wheel is slightly rotated by inertia, but soon the third contact comes into sliding contact with the protruding portion. As a result, the first contact and the third contact are electrically connected, and a back electromotive force is generated in the motor unit, which serves as a brake against inertial rotation of the worm wheel.

JP 2004-159433 A (FIG. 3) JP-A-10-157574 (FIG. 5)

  As described above, in the motor devices described in Patent Documents 1 and 2, the “auto stop function A” for stopping the supply of the drive current to the motor unit and the back electromotive force in the motor unit are generated and the brake is applied. Both “auto stop function B” are provided. Therefore, the electric circuit of the motor device requires an electric circuit (including wiring on the motor device side and the vehicle side) corresponding to each of the auto-stop functions A and B.

  In recent years, in order to reduce the size and weight of motor devices and to reduce costs, the “auto stop function B” that applies a brake to generate a counter electromotive force in the motor unit is omitted, and an attempt is made to reduce the parts required for the auto stop function B. There is a movement to do. Therefore, a technique for improving the stop position accuracy of the worm wheel, that is, the stop position accuracy of the wiper blade is required only by the “auto stop function A” for stopping the supply of the drive current to the motor unit.

  If the “auto stop function B” is simply omitted in Patent Documents 1 and 2 described above, the following problems may occur. That is, since the notch for obtaining the “auto stop function A” is formed in the inner peripheral portion of the conductive plate, the worm wheel with respect to the distance (for example, 3.0 mm) that the second contact travels within the notch by inertia. The rotation angle of the worm wheel is large, and as a result, the stop position of the worm wheel tends to vary. Therefore, it has been necessary to devise a fundamental review of the structure of the motor device so that the stop position accuracy can be improved.

  An object of the present invention is to provide a motor device capable of improving stop position accuracy as well as miniaturization and weight reduction and cost reduction.

  In the motor device of the present invention, a motor unit having a rotation shaft, a speed reduction mechanism unit having a speed reduction mechanism that decelerates rotation of the rotation shaft, a rotating body that forms the speed reduction mechanism and is rotated by the rotation shaft, An annular conductive plate provided on the rotating body, provided on a part of the outer periphery of the conductive plate, recessed on the radially inner side of the conductive plate, and provided on a part of the inner periphery of the conductive plate A plurality of contact plates that protrude inward in the radial direction of the conductive plate, and a plurality of contact plates that are slidably contacted with the conductive plate as the rotating body rotates to switch the energization state to the motor unit. The contact plate includes at least a first contact plate that is always in sliding contact with the conductive plate regardless of the rotational position of the rotating body, and a recess that passes through the rotation of the rotating body. And a second contact plate, wherein the plurality of contact plate has the same shape, respectively.

  In another aspect of the present invention, an outer peripheral side fixing claw and an inner peripheral side fixing claw for fixing the conductive plate to the rotating body are respectively provided on the outer peripheral portion and the inner peripheral portion of the conductive plate, The outer peripheral side fixed claws and the inner peripheral side fixed claws are disposed at positions that are relatively rotated by about 90 ° around the rotation center of the rotating body.

  In another aspect of the invention, the plurality of contact plates further include a third contact plate that passes through the convex portion as the rotating body rotates.

  In another aspect of the invention, the motor device is a wiper motor that drives a wiper blade.

  According to the present invention, since the concave portion through which the second contact plate passes as the rotating body rotates is provided in a part of the outer peripheral portion of the conductive plate, the distance that the second contact plate travels within the concave portion by inertia (for example, 3.0 mm), the rotation angle of the rotating body can be reduced, and as a result, variations in the stopping position of the rotating body are less likely to occur than before. This makes it possible to improve the stop position accuracy of the rotating body as well as to reduce the size and weight of the motor device and reduce the cost.

  In addition, since a convex portion protruding radially inward of the conductive plate is provided on a part of the inner peripheral portion of the conductive plate, it is possible to add a function of generating a counter electromotive force and applying a brake to the motor unit. It is possible to meet various needs.

It is a top view of the rear wiper motor mounted in a vehicle. It is a fragmentary sectional view which follows the AA line of FIG. It is the figure which looked at the connector unit and the worm wheel from the back side of FIG. It is the perspective view which looked at the connector unit from the deceleration mechanism part side. It is the elements on larger scale which compared the switching plate of this invention, and the switching plate of a prior art example. 6 is a plan view showing a speed reduction mechanism portion of a rear wiper motor according to Embodiment 2. FIG.

  Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings.

  1 is a plan view of a rear wiper motor mounted on a vehicle, FIG. 2 is a partial cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a view of a connector unit and a worm wheel as viewed from the back side of FIG. 4 is a perspective view of the connector unit as viewed from the speed reduction mechanism, and FIG. 5 is a partially enlarged view comparing the switching plate of the present invention with the switching plate of the conventional example.

  As shown in FIG. 1, a rear wiper motor 10 as a motor device is used as a drive source of a rear wiper device (not shown) mounted on a rear hatch of a vehicle, and includes a motor unit 20 and a speed reduction mechanism unit 30. Yes. The motor unit 20 and the speed reduction mechanism unit 30 are coupled together by a pair of fastening screws 11. The rear wiper motor 10 is disposed in a narrow space such as a rear hatch, and reciprocally wipes (oscillates) a wiper blade (not shown) provided on a rear glass (not shown) within a predetermined angle range.

  As shown in FIGS. 1 and 2, the motor unit 20 is configured as a four-pole motor with a brush. The motor unit 20 includes a motor case 21, and the motor case 21 is formed into a bottomed cylindrical shape by deep drawing a steel plate that is a magnetic body. The motor case 21 includes a pair of arc portions 21a and a pair of linear portions 21b, and the arc portions 21a and the linear portions 21b are arranged to face each other across the axis (armature shaft 24) of the motor case 21. . Thereby, the cross-sectional shape of the motor case 21 is formed in a substantially oval shape. Therefore, the width of the motor case 21, that is, the thickness dimension in the left-right direction in FIG.

  Each arc portion 21 a and each linear portion 21 b extend from the opening side to the bottom side of the motor case 21. As a result, the motor case 21 has a straight shape without a stepped portion, and as a result, the ease of deep drawing of the motor case 21 is improved. Further, as shown in FIG. 1, since the brush holder 70 does not enter the opening side of the motor case 21, the axial length of the motor case 21 is also suppressed. Thus, the motor case 21 is formed in an advantageous shape from the viewpoint of improving the moldability and reducing the size and weight.

  A total of four magnets 22 having a substantially arc-shaped cross section are mounted inside the motor case 21. Each magnet 22 is, for example, a ferrite magnet, and is fixed at equal intervals (90-degree intervals) along the circumferential direction of the motor case 21. Inside each magnet 22, an armature 23 is interposed via a predetermined gap. It is housed rotatably. The proximal end side of the armature shaft (rotating shaft) 24 is fixed through the rotation center of the armature 23.

  A commutator 25 is fixed to a substantially central portion along the axial direction of the armature shaft 24, and the commutator 25 includes ten segments 25a. An armature core 26 that forms the armature 23 is fixed to the base end side of the armature shaft 24, and the armature core 26 includes ten teeth 26a. Slots are formed between the teeth 26a. A plurality of armature coils 26b are wound around each tooth 26a with a predetermined winding method and a predetermined number of turns. The coil end of each armature coil 26b is electrically connected to each segment 25a.

  A plurality of power supply brushes 25b (only one is shown in FIG. 1) are in sliding contact with each segment 25a of the commutator 25. Each power supply brush 25b is movably provided on a brush holder 70 accommodated in the brush holder accommodating portion 34 of the housing 31, and a drive current from the connector unit 50 is supplied to each power supply brush 25b. Yes. As described above, the motor unit 20 and the connector unit 50 are electrically connected via the power supply brushes 25b, the commutator 25, and the armature coil 26b, whereby an electromagnetic force is generated in the armature coil 26b, and the armature 23 (armature The shaft 24) rotates. In FIG. 2, each power supply brush 25 b and the brush holder 70 are not shown for easy understanding.

  The base end side of the armature shaft 24 is rotatably accommodated in the motor case 21 and is supported only by a radial bearing 27 provided on the bottom side of the motor case 21. A thrust bearing that supports the armature shaft 24 from the axial direction is not provided between the base end side of the armature shaft 24 and the motor case 21. Here, the radial bearing 27 is formed in a substantially cylindrical shape by, for example, a sintered material, thereby having low noise, impact resistance, and self-lubricating properties, and further, abrasion powder is hardly generated. However, the radial bearing 27 may be formed of a plastic material having excellent heat resistance instead of the sintered material.

  A worm gear 24 a (not shown in detail) is integrally provided on the distal end side of the armature shaft 24, and the worm gear 24 a rotates in the housing 31 as the armature shaft 24 rotates. The worm gear 24 a is formed in a spiral shape and meshed with the gear teeth 32 a of the worm wheel 32. Here, the worm gear 24a and the worm wheel 32 constitute a reduction mechanism in the present invention. As the worm gear 24a rotates, the worm wheel 32 rotates in a decelerated state than the worm gear 24a, and outputs the rotation that has been decelerated and increased in torque to the outside.

  An inner ring member 28a of a ball bearing 28 is fixed between the armature 23 of the armature shaft 24 and the worm gear 24a by press-fitting. Further, the outer ring member 28 b of the ball bearing 28 is sandwiched between the housing 31 and the stopper plate 60. As a result, the armature shaft 24 is rotatably supported by the ball bearing 28, and movement in the axial direction and the radial direction with respect to the housing 31 is restricted. As described above, the ball bearing 28 has a function as a radial bearing and a thrust bearing. Therefore, a thrust bearing that supports the armature shaft 24 from the axial direction is not provided between the distal end side of the armature shaft 24 and the housing 31.

  Here, since the rear wiper motor 10 is configured as a small and light four-pole motor, the amount of heat generation is larger than that of a large two-pole motor having the same output, for example. However, since thrust bearings are not provided on both ends of the armature shaft 24 in the axial direction, the sliding loss of the armature shaft 24, that is, frictional resistance with the thrust bearing is eliminated, and an increase in the amount of heat generated is prevented. Like to do.

  As shown in FIG. 1, the speed reduction mechanism unit 30 includes a housing 31 formed in a substantially bathtub shape by casting a molten aluminum material or the like. The housing 31 includes a bottom part 31a and a wall part 31b, and an opening part 31c is provided on the side opposite to the bottom part 31a side. The opening 31c is closed by a gear cover (not shown), and the worm wheel 32, the connector unit 50, and the like are accommodated in the housing 31 from the opening 31c.

  A brush holder accommodating portion 34 is integrally provided on the motor portion 20 side of the housing 31. The brush holder accommodating portion 34 is formed in a cylindrical shape so as to extend along the axial direction of the armature shaft 24, and its cross-sectional shape is substantially oval like the cross-sectional shape of the motor case 21 (see FIG. 2). Is formed. Thereby, also in the brush holder accommodating part 34, the width dimension, ie, the thickness dimension of the depth direction in FIG.

  A worm wheel (rotating body) 32 shown in FIG. 3 is rotatably provided inside the housing 31. The worm wheel 32 is formed into a substantially disk shape by injection molding a resin material such as plastic. . Gear teeth 32a are integrally provided on the outer peripheral portion of the worm wheel 32, and the worm gear 24a (see FIG. 1) is engaged with the gear teeth 32a.

  One end in the axial direction of a wheel shaft 32b made of a steel rod having a circular cross section is fixed to the rotation center of the worm wheel 32, and the other end in the axial direction of the wheel shaft 32b is provided on the bottom 31a of the housing 31. A boss (not shown) is rotatably supported.

  A pair of outer peripheral side engagement holes 32c are provided closer to the gear teeth 32a than the wheel shaft 32b of the worm wheel 32 so as to sandwich the wheel shaft 32b. Further, a pair of inner peripheral side engagement holes 32d facing each other so as to sandwich the wheel shaft 32b are provided closer to the wheel shaft 32b than the gear teeth 32a of the worm wheel 32. The outer peripheral side engagement holes 32c and the inner peripheral side engagement holes 32d are arranged at positions that are relatively rotated by about 90 ° around the axis of the wheel shaft 32b.

  Respective fixing claws 33c and 33d for fixing the switching plate 33 to the worm wheel 32 are inserted into the engagement holes 32c and 32d, respectively. Accordingly, the outer peripheral portion 33a and the inner peripheral portion 33b of the switching plate 33 can be firmly fixed without rattling with respect to the worm wheel 32.

  On the bottom 31a side of the worm wheel 32, as shown by the hatched portion in FIG. 3, a switching plate (conductive plate) made of a conductive steel plate is provided. The switching plate 33 is formed of brass or the like having excellent conductivity, and is formed in a substantially annular shape by performing press processing (such as punching processing).

  On the outer peripheral portion 33a and the inner peripheral portion 33b of the switching plate 33, there are an outer peripheral side fixing claw (fixed claw) 33c and an inner peripheral side fixed claw (fixed claw) 33d that are bent substantially perpendicular to the thickness direction of the switching plate 33. Two each are provided. The fixing claws 33c and 33d are provided corresponding to the engaging holes 32c and 32d, respectively. That is, each outer peripheral side fixed claw 33c and each inner peripheral side fixed claw 33d are arranged at positions that are relatively rotated by about 90 ° around the axis of the wheel shaft 32b.

  A recess 33 e that is recessed radially inward of the switching plate 33 is provided in a part of the outer peripheral portion 33 a of the switching plate 33. A convex portion 33 f that protrudes radially inward of the switching plate 33 is provided on a part of the inner peripheral portion 33 b of the switching plate 33. Further, an annular plate body 33g having no irregularities is provided between the outer peripheral portion 33a and the inner peripheral portion 33b along the radial direction of the switching plate 33.

  A portion of the switching plate 33 corresponding to the plate body 33g, a portion corresponding to the concave portion 33e, and a portion corresponding to the convex portion 33f are respectively provided with a first sliding contact portion 33h and a second sliding portion 33h extending in the circumferential direction of the switching plate 33. A sliding contact portion 33i and a third sliding contact portion 33j (two-dot chain line in the figure) are formed. In each of the first sliding contact portion 33h and the second sliding contact portion 33i, the tip portions of the first contact plate CP1 and the second contact plate CP2 provided in the connector unit 50 as the worm wheel 32 rotates. Are in sliding contact with each other.

  Here, in the present embodiment, nothing comes into sliding contact with the third sliding contact portion 33j. That is, the present embodiment has a structure that does not have a function of generating a counter electromotive force in the motor unit 20 and applying a brake. However, since the third sliding contact portion 33j corresponding to the convex portion 33f is provided, when a braking function by a counter electromotive force is required, a connector unit that can exhibit the function, that is, the first to third contacts. It can be easily handled by simply replacing the connector unit with a plate. As described above, in the rear wiper motor 10, the components are made common, and the cost is reduced. In addition, as an electric circuit that exhibits the braking function by the counter electromotive force, an electric circuit (not shown) in which a closed loop circuit is formed according to the rotational position of the worm wheel 32 is used as in the conventional circuit. It is done.

  In this way, the first contact plate CP1, which is slidably in contact with the first slidable contact portion 33h, is always in contact with the switching plate 33, and the second slidable contact portion 33i is in slidable contact with the switching plate 33 by the recess 33e. By providing the second contact plate CP2 that is disconnected, the energized state and the non-energized state of each contact plate CP1, CP2 are sent to the in-vehicle controller (not shown) via the connector unit 50. As a result, the in-vehicle controller turns off the wiper switch (not shown) by the driver, and the contact plates CP1 and CP2 are in a non-energized state (the second contact plate CP2 reaches the recess 33e). ) Is stopped, the supply of drive current to the motor unit 20 is stopped. As a result, the wiper blade can be stopped at a predetermined stop position.

  As shown in FIG. 1, an output shaft 35 made of a steel rod having a circular cross section is accommodated in a portion (left side in the drawing) of the housing 31 away from the worm wheel 32. The output shaft 35 is rotatably supported by a boss (not shown) provided on the bottom 31 a of the housing 31. A base end portion of the wiper blade is fixed to an extended portion (not shown) extending to the outside of the output shaft 35.

  In the housing 31, a motion conversion mechanism 40 that converts the rotational motion of the worm wheel 32 into the swing motion of the output shaft 35 is provided between the proximal end side of the output shaft 35 and the worm wheel 32. The motion conversion mechanism 40 includes a swing link 41, a connecting plate 42, and a sliding contact plate 43.

  The swing link 41 is formed in a plate shape by punching a steel plate or the like, and one longitudinal end side of the swing link 41 is fixed to the base end side of the output shaft 35. On the other hand, the other end side in the longitudinal direction of the swing link 41 is rotatably connected to one end side in the longitudinal direction of the connecting plate 42 via the first connecting pin P1. The other end in the longitudinal direction of the connecting plate 42 is rotatably connected to a position eccentric from the rotation center of the worm wheel 32 via the second connecting pin P2. Here, the length dimension of the swing link 41 is set to be approximately half (substantially 1/2) the length dimension of the connecting plate 42. The connecting plate 42 is also formed in a plate shape by punching a steel plate or the like in the same manner as the swing link 41.

  Thus, by providing the motion conversion mechanism 40 between the output shaft 35 and the worm wheel 32, the output shaft 35 can be swung within a predetermined angle range as the worm wheel 32 rotates in one direction. Yes. Specifically, the rotational force reduced and increased in torque by the rotation of the worm gear 24a and the worm wheel 32 is transmitted to the second connecting pin P2, and the second connecting pin P2 rotates around the wheel shaft 32b. Then, the longitudinal direction other end side of the connection plate 42 also rotates around the wheel shaft 32b, and thereby the longitudinal direction one end side of the connection plate 42 is regulated by the swing link 41 via the first connection pin P1. Oscillates around the output shaft 35.

  The sliding contact plate 43 is formed in a plate shape from a resin material such as plastic having excellent self-lubricating properties, and is mounted on the gear cover side (front side in FIG. 1) of the connecting plate 42. A slidable contact portion 43a that is in slidable contact with the gear cover is integrally provided at a central portion in the longitudinal direction of the slidable contact plate 43, and grease (not shown) is applied to the slidable contact portion 43a. Thus, the motion conversion mechanism 40 is smoothly moved in the housing 31 and the motion conversion mechanism 40 is prevented from rattling along the axial direction of the output shaft 35 (the depth direction in FIG. 1).

  As shown in FIG. 4, the connector unit 50 is formed into a predetermined shape by injection molding a resin material such as plastic, and a connector body 51 formed in a plate shape and a connector formed in a box shape with a bottom. The connection part 52 is provided.

  The connector unit 50 is provided so as to straddle the armature shaft 24, and a through cylinder portion 51 a through which the armature shaft 24 (see FIG. 1) passes is formed at a substantially central portion of the connector main body portion 51. The inner diameter dimension of the through cylinder 51a is set to be slightly larger than the outer diameter dimension of the ball bearing 28 (see FIG. 1). As a result, the armature shaft 24 having the ball bearing 28 can pass through the connector main body 51 when the rear wiper motor 10 is assembled.

  A connector connecting portion 52 is disposed on one side (right side in FIG. 4) of the connector main body portion 51 sandwiching the armature shaft 24. On the other hand, a contact plate support 51b is integrally provided on the other side (left side in FIG. 4) sandwiching the armature shaft 24 of the connector main body 51, and the contact plate support 51b extends from the surface 51c of the connector main body 51. It protrudes in the axial direction of the armature shaft 24.

  A first contact plate CP1 and a second contact plate CP2 for switching the energization state to the motor unit 20 (see FIGS. 1 and 2) are arranged in parallel with the contact plate support 51b so as to be aligned in the radial direction of the armature shaft 24. It is installed. Each of these contact plates CP1 and CP2 is inserted and fixed from one side of the connector main body 51 in the short direction (the lower side in FIG. 4).

  Regardless of the rotational position of the worm wheel 32, the first contact plate CP1 is always in sliding contact with the switching plate 33, and is disposed on the side opposite to the connector connecting portion 52 side of the connector unit 50. On the other hand, the second contact plate CP <b> 2 passes through the recess 33 e of the switching plate 33 with the rotation of the worm wheel 32, and is disposed near the connector connecting portion 52 of the connector unit 50.

  Accordingly, the second jumper line JP2 corresponding to the second contact plate CP2 is shorter than the first jumper line JP1 corresponding to the first contact plate CP1. Here, each jumper wire JP1, JP2 is between each contact plate CP1, CP2 and the base end side of each male terminal TM1 and the base end side of each female terminal TM2 provided on the connector connecting portion 52 side. Are electrically connected to each other by spot welding or the like.

  A plurality of male terminals TM1 and female terminals TM2 are provided on the connector connecting portion 52 side. A vehicle-side external connector (not shown) connected to the connector connection portion 52 is electrically connected to the distal end side of each male terminal TM1, and a brush holder 70 is connected to the distal end side of each female terminal TM2. Each male terminal (not shown) provided in is inserted and connected.

  Here, as described above, the connector unit 50 does not include an electric circuit that exhibits a braking function based on the counter electromotive force, and includes only the first contact plate CP1 and the second contact plate CP2. . Therefore, as shown in FIG. 3, the width dimension W of the connector unit 50 is shortened, so that the rear wiper motor 10 is reduced in size and weight. In the case where a third contact plate (not shown) that exhibits a braking function by back electromotive force is provided, the third contact plate needs to be brought into sliding contact with the third sliding contact portion 33j. The width dimension increases.

  Next, the point that the stop position accuracy of the rear wiper motor 10 formed as described above (without the braking function due to the counter electromotive force) is improved as compared with the prior art will be described in detail with reference to the drawings.

  As shown in [Invention] of FIG. 5A, when the driver turns off the wiper switch from the state in which the worm wheel 32 is rotating in the direction of arrow R (counterclockwise), the second contact When the plate CP2 (see FIG. 3) is in sliding contact with the second sliding contact portion 33i and is electrically connected to the switching plate 33 (in the energized state), the motor portion 20 (see FIGS. 1 and 2). ) Is continuously supplied. That is, the rear wiper motor 10 (see FIG. 1) is continuously driven despite the wiper switch being turned off. Thereby, the wiper blade is moved toward a predetermined stop position.

  Thereafter, when the second contact plate CP2 reaches the recess 33e, the supply of the drive current to the motor unit 20 is stopped, and the rear wiper motor 10 is stopped. At this time, the worm wheel 32 is rotated by inertia, and the second contact plate CP2 advances through the recess 33e by the distance L1 and is stopped at the stop point SP. Thereby, the wiper blade is stopped at a predetermined stop position. Here, the distance L1 that the second contact plate CP2 travels in the recess 33e by inertia is, for example, 3.0 mm, and the rotation angle of the worm wheel 32 is β ° (about 12 °).

  On the other hand, as shown in [Conventional Example] in FIG. 5B, since the recess b corresponding to the second sliding contact portion a is in the inner peripheral portion of the switching plate c, the second contact plate passes through the recess b. Assuming that the vehicle travels a distance L1 (for example, 3.0 mm) and stops at the stop point SP, the rotation angle of the worm wheel d is γ ° (about 24 °) larger than β ° (about 12 °). (Γ °> β °).

  This means that when the distance L1 varies due to the magnitude of the external force applied to the wiper blade, the accuracy of the stop position can be worse in the conventional example than in the present invention. Yes. Further, as shown in FIGS. 5A and 5B, the recesses 33e and b are formed in the same angular range α ° of the worm wheels 32 and d, and the length dimension along the circumferential direction of the recesses 33e. L2 (this invention) can be set to a dimension longer than the length dimension L3 (conventional example) along the circumferential direction of the recessed part b (L2> L3).

  Therefore, even if the worm wheel 32 is rotated largely by inertia, the second contact plate CP2 is not rotated beyond the recess 33e in the present invention, and the rear wiper motor 10 is surely stopped. Can do. On the other hand, in the conventional example, when the worm wheel 32 is rotated largely by inertia, the second contact plate may exceed the recess b, so that a braking function by a counter electromotive force is necessary.

  As described above in detail, according to the rear wiper motor 10 according to the first embodiment, the recess 33e through which the second contact plate CP2 passes through the rotation of the worm wheel 32 is formed in a part of the outer peripheral portion 33a of the switching plate 33. Since it is provided, the rotation angle β ° of the worm wheel 32 can be reduced with respect to the distance L1 (for example, 3.0 mm) in which the second contact plate CP2 travels in the recess 33e by inertia, and as a result, the worm is compared with the former. Variations in the stop position of the wheel 32 are less likely to occur. As a result, not only the rear wiper motor 10 can be reduced in size and weight and the cost can be reduced, but also the stop position accuracy of the worm wheel 32 can be improved.

  Further, according to the rear wiper motor 10 according to the first embodiment, since the convex portion 33f protruding inward in the radial direction of the switching plate 33 is provided in a part of the inner peripheral portion 33b of the switching plate 33, the motor portion 20 A function of generating a back electromotive force and applying a brake can be added to meet various needs.

  Furthermore, according to the rear wiper motor 10 according to the first embodiment, since the concave portion 33e is formed on a part of the outer peripheral portion 33a of the switching plate 33, a convex portion is formed on a part of the outer peripheral portion of the conventional switching plate. Compared to (see FIG. 5B), generation of useless portions of the base material (material) of the switching plate can be suppressed, and the yield can be improved.

  Next, Embodiment 2 of the present invention will be described in detail with reference to the drawings. Note that portions having the same functions as those of the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 6 is a plan view showing a speed reduction mechanism portion of the rear wiper motor according to the second embodiment.

  As shown in FIG. 6, the rear wiper motor (motor device) 80 according to the second embodiment has a position and motion conversion mechanism of the output shaft 35 as compared with the rear wiper motor 10 according to the first embodiment (see FIG. 1). 90 structures are different.

  The output shaft 35 of the rear wiper motor 80 is disposed on the opposite side of the armature shaft 24 with the worm wheel 32 of the housing 81 interposed therebetween. Thereby, in the rear wiper motor 80, the dimension along the axial direction of the armature shaft 24 can be reduced as compared with the first embodiment.

  The motion conversion mechanism 90 of the rear wiper motor 80 includes a pinion gear 91, a motion conversion member 92, a connecting plate 42, and a sliding contact plate 43. The pinion gear 91 is fixed to the base end side of the output shaft 35 and swings with the output shaft 35.

  The motion converting member 92 includes a sector gear 92a that meshes with the pinion gear 91, and an arm portion 92b that is rotatably connected to the eccentric position of the worm wheel 32 via the second connecting pin P2. A first connecting pin P1 is provided at the central portion of the sector gear 92a, and a connecting plate 42 is provided between the first connecting pin P1 and the output shaft 35. Specifically, one end side in the longitudinal direction of the connecting plate 42 is rotatably connected to the base end side of the output shaft 35, and the other end side in the longitudinal direction of the connecting plate 42 is rotatably connected to the first connecting pin P1. Has been. As described above, the connecting plate 42 according to the second embodiment keeps the distance between the output shaft 35 and the first connecting pin P1 constant, and maintains the engagement between the pinion gear 91 and the sector gear 92a.

  Also in the motion conversion mechanism 90 of the rear wiper motor 80, the rotational motion of the worm wheel 32 is converted into the swing motion of the output shaft 35. Specifically, when the second connecting pin P2 rotates about the wheel shaft 32b as the worm wheel 32 rotates, the arm portion 92b of the motion conversion member 92 also rotates about the wheel shaft 32b. As a result, the sector gear 92a swings about the first connecting pin P1, and as a result, the pinion gear 91 that meshes with the sector gear 92a, that is, the output shaft 35 swings.

  As described in detail above, the rear wiper motor 80 according to the second embodiment can achieve the same operational effects as those of the first embodiment described above.

  It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiments, the cross-sectional shapes of the motor case 21 and the brush holder accommodating portion 34 are shown as substantially oval shapes, but the present invention is not limited to this, for example, an oval shape. It can also be formed in a shape or a rectangular shape.

  In each of the above-described embodiments, the reduction gear mechanism (worm reduction gear) composed of the worm gear 24a and the worm wheel 32 is used. However, the present invention is not limited to this, and for example, a planetary gear reduction gear as the reduction gear mechanism. Can also be adopted. In this case, for example, the sun gear may be an input side (armature shaft 24 side) gear, and the ring gear may be an output side (output shaft 35 side) gear.

  Furthermore, in each of the above-described embodiments, a ferrite magnet is used as each magnet 22. However, the present invention is not limited to this, and a plate magnet made of a neodymium magnet or the like can also be used. The number of magnets, the number of segments, the number of teeth, etc. may be freely set according to the specifications required for the motor unit.

10 Rear wiper motor (motor device)
DESCRIPTION OF SYMBOLS 11 Fastening screw 20 Motor part 21 Motor case 21a Arc part 21b Linear part 22 Magnet 23 Armature 24 Armature axis (rotary axis)
24a Worm gear (deceleration mechanism)
25 Commutator 25a Segment 25b Power supply brush 26 Armature core 26a Teeth 26b Armature coil 27 Radial bearing 28 Ball bearing 28a Inner ring member 28b Outer ring member 30 Deceleration mechanism part 31 Housing 31a Bottom part 31b Wall part 31c Opening part 32 Worm wheel (Rotating body, Deceleration mechanism) )
32a Gear teeth 32b Wheel shaft 32c Outer peripheral side engagement hole 32d Inner peripheral side engagement hole 33 Switching plate (conductive plate)
33a outer peripheral part 33b inner peripheral part 33c outer peripheral side fixing claw (fixing claw)
33d Inner peripheral side fixed claw (fixed claw)
33e Concave portion 33f Convex portion 33g Plate body 33h First sliding contact portion 33i Second sliding contact portion 33j Third sliding contact portion 34 Brush holder housing portion 35 Output shaft 40 Motion conversion mechanism 41 Swing link 42 Connecting plate 43 Sliding contact plate 43a Sliding contact portion 50 Connector unit 51 Connector body portion 51a Through tube portion 51b Contact plate support portion 51c Surface 52 Connector connection portion 60 Stopper plate 70 Brush holder 80 Rear wiper motor 81 Housing 90 Motion conversion mechanism 91 Pinion gear 92 Motion conversion member 92a Sector gear 92b Arm Part CP1 First contact plate CP2 Second contact plate JP1 First jumper line JP2 Second jumper line P1 First connection pin P2 Second connection pin SP Stop point TM1 Male terminal TM2 Female terminal

Claims (4)

A motor unit having a rotating shaft;
A speed reduction mechanism having a speed reduction mechanism for reducing the rotation of the rotation shaft;
A rotating body that forms the deceleration mechanism and is rotated by the rotating shaft;
An annular conductive plate provided on the rotating body;
A concave portion provided in a part of the outer peripheral portion of the conductive plate, recessed in the radial direction of the conductive plate;
Protruding portions provided on a part of the inner peripheral portion of the conductive plate and protruding radially inward of the conductive plate;
A plurality of contact plates that are slidably contacted with the conductive plate as the rotating body rotates and switch the energization state to the motor unit;
With
The plurality of contact plates include at least a first contact plate that is always in sliding contact with the conductive plate regardless of a rotational position of the rotating body, and a second contact plate that passes through the recess as the rotating body rotates.
Have
Each of the plurality of contact plates has the same shape.
Motor device. The motor device according to claim 1,
An outer peripheral side fixing claw and an inner peripheral side fixing claw for fixing the conductive plate to the rotating body are provided on the outer peripheral portion and the inner peripheral portion of the conductive plate, respectively.
The outer peripheral side fixed claw and the inner peripheral side fixed claw are disposed at positions that are relatively rotated by about 90 ° around the rotation center of the rotating body,
Motor device. The motor apparatus according to claim 1 or 2,
The plurality of contact plates further include a third contact plate that passes through the convex portion as the rotating body rotates.
Motor device. In the motor device according to any one of claims 1 to 3,
The motor device is a wiper motor that drives a wiper blade.
Motor device.

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