JP2010098796A - Motor with speed reducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the airtightness inside a case, in a motor with a speed reducer which is so arranged as to adjust the thrust of a rotating shaft by the injection of resin into the case. <P>SOLUTION: In a power window motor, which is so arranged as to adjust the thrust of a worm shaft 28 by injecting resin 54 into the injection space 51 of a worm storage chamber 26a thereby pressing a thrust plate 32 against the end face on the axial chip side of the worm shaft 28 (a rotating shaft 13) via a steel ball 33, an injection hole 53, which connects the injection space 51 with its outside, and an outer wall 55, which is so projected on a gear case 25 as to surround the injection hole 53, are provided, and the injection hole 53 is shifted in a direction (axial chip side) where its center line C1 is separated from a thrust plate 32 as against the center line C2 of the outer wall 55. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor with a speed reduction mechanism that adjusts thrust of a rotating shaft by injecting resin into a case.

  As an actuator for a power window device mounted on a vehicle such as an automobile, a reduction mechanism for increasing the rotational force of the rotating shaft is provided in order to open and close the window glass by a small drive source that can be housed in the door. A motor with a speed reduction mechanism is used. The motor with a speed reduction mechanism includes an electric motor as a drive source, and a speed reduction mechanism including a worm integrally provided on a rotating shaft of the electric motor and a worm wheel meshing with the worm. Then, the rotation of the rotary shaft is decelerated by the speed reduction mechanism, and the driving force with high output is transmitted to the window regulator, so that the window glass supported by the window regulator is opened and closed.

  The motor with a speed reduction mechanism has a gear case in which a worm housing portion in which a worm of a rotating shaft is housed and a worm wheel housing portion in which a worm wheel is housed are integrally formed. The worm and the worm wheel are engaged with each other inside the gear case, and the worm, that is, the rotation shaft is slightly reciprocated in the axial direction in accordance with the engagement. For this reason, if there is a clearance between the end surface on the axial front end side of the rotating shaft and the gear case, the rotating shaft collides with the gear case during reciprocating movement of the rotating shaft and generates a hitting sound. Therefore, in order to suppress the occurrence of such a hitting sound, a thrust plate for supporting the rotating shaft from the axial front end side is provided inside the gear case, and the thrust plate is axially moved by the resin injection into the gear case. For example, Patent Document 1 discloses a motor with a speed reduction mechanism that is disposed at a position where it can abut on the end face on the front end side and eliminates play in the gear case of the rotating shaft.

In the motor with a speed reduction mechanism described in Patent Document 1, the inside of the worm housing portion of the gear case is in the axially proximal end side rotational shaft housing chamber in which the rotational shaft is housed by the thrust plate, and the axial direction of the rotational shaft. This is divided into an injection space on the tip end side in the axial direction that communicates with the outside through an injection hole formed in the vertical direction. Thrust adjustment of the rotating shaft is performed by injecting resin into this injection space through the injection hole Like to do. The gear case is formed with an outer wall protruding so as to surround the injection hole, and at the time of resin injection, a nozzle for resin injection is abutted against the outer wall to position the nozzle.
JP 2003-106330 A

  By the way, in such thrust adjustment of the rotating shaft by injecting resin into the gear case, a thermoplastic resin made of a material different from that of the resin gear case is injected into the gear case. Therefore, a slight gap may be formed at the interface between the gear case and the resin, and the airtightness inside the gear case becomes a problem. That is, rainwater or the like may enter the gear case from the outside along the interface between the gear case and the resin, and the durability of the rotating shaft and the worm wheel may be reduced. Therefore, it is desired to improve the airtightness inside the gear case by increasing the distance (creeping distance) along the interface between the gear case and the resin from the outside of the gear case to the inside of the gear case (rotating shaft accommodating chamber).

  However, in the motor with a speed reduction mechanism described in Patent Document 1, since the injection hole is formed in a state where the center thereof coincides with the center of the outer wall, the axial base end side of the outer wall in the axial section of the rotation shaft The minimum creepage distance from the opening end of the (thrust plate side) to the inside of the gear case (rotating shaft housing chamber) is extremely small compared to the creeping distance from the opening end of the outer wall in the axial direction to the inside of the gear case. The airtightness was worsened.

  An object of the present invention is to improve airtightness inside a case in a motor with a speed reduction mechanism that adjusts the thrust of a rotating shaft by injecting resin into the case.

  The motor with a speed reduction mechanism according to the present invention communicates with the outside through a rotating shaft housing chamber in which the rotating shaft of the electric motor is housed and an injection hole opened in a direction perpendicular to the axial direction of the rotating shaft, and the rotating shaft. A gear case in which an injection space formed continuously with the storage chamber is formed; and a thrust plate which is stored in the gear case and separates the rotary shaft storage chamber and the injection space; A motor with a speed reduction mechanism that adjusts the thrust of the rotating shaft by injecting resin into a space, wherein the gear case is formed with an outer wall that surrounds the injecting hole, and the injection hole is formed on the rotating shaft. In the axial direction, the center of the injection hole is arranged in a direction away from the thrust plate than the center of the outer wall.

  The motor with a speed reduction mechanism according to the present invention communicates with the outside through a rotating shaft housing chamber in which the rotating shaft of the electric motor is housed and an injection hole opened in a direction perpendicular to the axial direction of the rotating shaft, and the rotating shaft. A gear case in which an injection space formed continuously with the storage chamber is formed; and a thrust plate which is stored in the gear case and separates the rotary shaft storage chamber and the injection space; A motor with a speed reduction mechanism that adjusts the thrust of the rotary shaft by injecting resin into a space, wherein the gear case is formed with an outer wall that surrounds the injection hole, and the injection hole is formed on the rotary shaft. In the axial direction, it is arranged in a region on the direction side away from the thrust plate from the center of the outer wall.

  The motor with a speed reduction mechanism according to the present invention communicates with the outside through a rotating shaft housing chamber in which the rotating shaft of the electric motor is housed and an injection hole opened in a direction perpendicular to the axial direction of the rotating shaft, and the rotating shaft. A gear case in which an injection space formed continuously with the storage chamber is formed; and a thrust plate which is stored in the gear case and separates the rotary shaft storage chamber and the injection space; A motor with a speed reduction mechanism that adjusts the thrust of the rotating shaft by injecting resin into a space, wherein an outer wall that surrounds the injection hole protrudes from the gear case, and the injection hole has a thrust plate side. The side surface of the rotating shaft is disposed on the side of the direction away from the thrust plate from the center of the outer wall in the axial direction of the rotating shaft. That.

  The motor with a speed reduction mechanism of the present invention is characterized in that a protrusion is formed on the outer wall from the inner peripheral surface of the outer wall toward the center of the outer wall.

  In the motor with a speed reduction mechanism of the present invention, the protrusion includes a first end surface coupled to the inner peripheral surface of the outer wall, and a second end surface formed in the center direction of the outer wall from the first end surface. The width of the first end face and the second end face is formed larger on the second end face than on the first end face.

  According to the present invention, in the axial direction of the rotation shaft, the center of the injection hole is arranged in a direction (axial tip side) farther from the thrust plate than the center of the outer wall. The minimum creepage distance can be increased as compared with the case where the center and the center are formed, and the airtightness inside the gear case can be improved. That is, since the minimum creepage distance along the interface between the gear case and the resin is increased, it is possible to suppress rainwater or the like from entering the gear case along the interface.

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

  FIG. 1 is a partially cutaway plan view of a power window motor according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA in FIG.

  The power window motor 10 is provided in a power window device (not shown) mounted inside a door of a vehicle, and drives a window regulator (elevating mechanism) that opens and closes the window glass. The power window motor 10 is a motor with a speed reduction mechanism in which the electric motor 11 and a speed reduction mechanism that reduces the rotation of the electric motor 11 and transmits it to the window regulator are a unit, and the electric motor 11 that is a drive source and the speed reduction mechanism. The gear part 12 provided with this.

  The electric motor 11 is a DC motor with a brush, and a rotating shaft 13 (an armature shaft 17 and a worm shaft 28 described later) provided on the electric motor 11 can rotate in both forward and reverse directions. The electric motor 11 includes a motor case (yoke) 14 formed by press-forming a thin steel plate made of a magnetic material into a bottomed stepped cylindrical shape, and a radial direction inside a cylindrical portion 14a of the motor case 14. A pair of permanent magnets 15 facing each other, and a rotor (armature rotor) 16 that is rotatably provided inside each permanent magnet 15 via a predetermined gap.

  An armature shaft 17 is provided through the shaft center of the rotor 16, and ends of the armature shaft 17 on the axial base end side (left side in FIG. 1) and the axial front end side (right side in FIG. 1). Are rotatably supported by an annular radial bearing 18 attached to the stepped bottom 14b of the motor case 14 and an annular radial bearing 19 attached to a brush holder 23 described later. The end surface of the armature shaft 17 on the base end side in the axial direction is adjacent to the base end side in the axial direction of the radial bearing 18 on the thrust plate 20 disposed on the stepped bottom 14b of the motor case 14 via the steel ball 21. The thrust plate 20 supports the thrust load in the axial base end side direction of the armature shaft 17 (rotating shaft 13).

  A commutator 22 electrically connected to a coil 16 a wound around the rotor 16 is provided adjacent to the axial front end side of the rotor 16 on the axial front end side of the armature shaft 17. The commutator 22 is slidably contacted with a predetermined elastic force by a brush 23 a provided on a resin brush holder 23 mounted on the opening side of the motor case 14.

  The electric motor 11 is attached to the gear case 25 of the gear portion 12 by a plurality of bolts 24 at a flange portion 14 c provided on the opening side of the motor case 14. The resin gear case 25 includes a worm housing portion 26 that extends in the axial direction of the armature shaft 17 (rotating shaft 13) and opens to the electric motor 11 side (axial tip side). The electric motor 11 includes the worm housing portion. The end of the armature shaft 17 on the distal end side in the axial direction is fixed to the opening end face of the portion 26 and protrudes into a worm housing chamber 26 a formed inside the worm housing 26.

  A connector unit (not shown) for supplying power to the rotor 16 (coil 16a) of the electric motor 11 through the brush 23a of the brush holder 23 is mounted on the opening side of the worm storage chamber 26a. The connector unit is connected to a power supply connector on the vehicle side and is electrically connected to a lead plate provided on the brush holder 23 to constitute an electric circuit connecting the power supply connector on the vehicle side and the rotor 16. When the electric motor 11 is supplied with power through this connector unit, the armature shaft 17 (rotary shaft 13) is rotated in the forward direction or the reverse direction.

  At the end of the armature shaft 17 projecting into the worm storage chamber 26 a on the distal end side in the axial direction, the end of the worm shaft 28 arranged on the same axis as the armature shaft 17 is connected to the axially proximal end by the connector 29. The worm shaft 28 is connected to the armature shaft 17 so as to be rotated integrally therewith. That is, the rotating shaft 13 of the electric motor 11 has a split shaft structure formed by the armature shaft 17 and the worm shaft 28.

  The axially proximal end side and the axially distal end side end portion of the worm shaft 28 are rotatably supported by annular radial bearings 30 and 31 mounted in the worm storage chamber 26a. Further, the end surface of the worm shaft 28 on the front end side in the axial direction is brought into contact with the thrust plate 32 disposed on the front end side in the axial direction of the worm housing chamber 26 a adjacent to the front end side in the axial direction of the radial bearing 31 via the steel ball 33. The thrust plate 32 supports a thrust load in the axial front end direction of the worm shaft 28 (rotating shaft 13). As shown in FIG. 2, a worm 28a is integrally provided on the outer periphery of the central portion of the worm shaft 28 in the axial direction.

  The gear case 25 includes a worm wheel housing portion 35 formed integrally with the worm housing portion 26, and a tooth portion 36a meshing with the worm 28a is provided in the worm housing chamber 35a formed inside the worm wheel housing portion 35. The worm wheel 36 formed in the housing is accommodated. The worm wheel housing portion 35 has a bottomed cylindrical shape that opens in a direction orthogonal to the opening side of the worm housing portion 26 in the gear case 25, and a support shaft 37 is provided on the shaft center of the worm wheel housing portion 35. It is fixed in a state of protruding from the bottom cover 38 attached to the opening of the accommodating portion 35. The worm wheel 36 is rotatably supported in the worm wheel housing chamber 35 a by a cylindrical portion 35 c extending from the bottom wall portion 35 b of the worm wheel housing portion 35 along the outer periphery of the support shaft 37.

  The worm wheel housing portion 35 is integrally formed adjacent to the worm housing portion 26, and the worm wheel housing portion 35 is connected to the worm housing portion 26 side so as to communicate the worm housing chamber 26a and the worm wheel housing chamber 35a. A hole 39 is formed. The worm 28a of the worm shaft 28 accommodated in the worm accommodating chamber 26a and the tooth portion 36a of the worm wheel 36 accommodated in the worm wheel accommodating chamber 35a are engaged with each other through the communication hole 39. Further, a rotation mechanism with a high output is output by reducing the rotation of the electric motor 11 to a predetermined speed by a speed reduction mechanism including the worm wheel 36.

  The worm wheel 36 is a worm wheel with a damper, and the rotation of the worm wheel 36 is transmitted to the driven plate 41 via the damper member 40. That is, the driven plate 41 is rotatable relative to the worm wheel 36 within a range in which the damper member 40 is elastically deformed, and the damper member 40 reduces the impact transmitted from the window regulator to the driven plate 41, The impact is not transmitted to the worm wheel 36.

  The driven plate 41 is provided with an output gear 42 that protrudes from the bottom cover 37 to the outside of the worm wheel housing chamber 35a. The output gear 42 and the drive gear of the window regulator mesh with each other to drive the window regulator. A seal member 43 is attached to the inner surface of the bottom cover 37, and the worm wheel storage chamber 35a is sealed by the seal member 43, so that rainwater or the like can be prevented from entering the worm wheel storage chamber 35a. ing.

  In this power window motor 10, the thrust plate 32 is pressed against the end face of the worm shaft 28 (rotary shaft 13) in the axial direction through the steel ball 33 by injecting resin into the worm housing portion 26 of the gear case 25. Thus, a thrust adjustment structure is provided for adjusting the thrust of the worm shaft 28.

  FIG. 3 is an enlarged cross-sectional view taken along line BB shown in FIG. 1, and shows an axial cross-sectional view of a thrust adjustment structure provided in the power window motor 10. 4A is an exploded perspective view of the thrust adjustment structure shown in FIG. 3, and FIG. 4B is a view taken in the direction of arrow C in FIG.

  As shown in FIG. 3, this thrust adjustment structure is provided on the axially distal end side of the worm accommodating portion 26 in which the axially distal end side (right side in FIG. 3) of the worm shaft 28 (rotating shaft 13) is accommodated. It has been. The tip end side in the axial direction of the worm storage chamber 26a is formed in a plurality of stepped shapes so that the inner diameter becomes smaller toward the tip end side in the axial direction. The worm storage chamber 26a includes an axial base end side (left side in FIG. 3) in which the worm shaft 28 is stored, and the rotary shaft storage chamber by a thrust plate 32 stored on the axial front end side. 50 is divided in the axial direction into an injection space 51 on the tip end side in the axial direction formed continuously with 50.

  The thrust plate 32 has a disc shape that is formed between the rotating shaft accommodation chamber 50 and the injection space 51, that is, approximately the same diameter as the inner diameter of the worm accommodation chamber 26a at the position where the thrust plate 32 is disposed. A resin 54 (described later) is slidably disposed in the worm storage chamber 26a in the axial direction so as not to leak from the injection space 51 to the rotary shaft storage chamber 50. The end surface of the thrust plate 32 on the axial base end side (rotating shaft accommodation chamber 50 side) is a plane perpendicular to the axial direction of the worm shaft 28, and the steel is attached to the end surface of the worm shaft 28 on the distal end side in the axial direction. Point contact with the ball 33 is possible. Further, as shown in FIG. 4, a substantially rectangular recess 32 a is formed on the end surface of the thrust plate 32 on the axial front end side (injection space 51 side), and the recess 32 a communicates with the injection space 51. Yes.

  The rotary shaft accommodating chamber 50 accommodates the worm shaft 28 (rotating shaft 13), and the end of the worm shaft 28 on the distal end side in the axial direction is adjacent to the axial base end side of the thrust plate 32 and accommodates the rotary shaft. A radial bearing 31 provided in the chamber 50 is rotatably supported. A circular recess 28b is formed on the end surface of the worm shaft 28 on the front end side in the axial direction, and the steel ball 33 is directed from the end surface on the front end side in the axial direction of the worm shaft 28 toward the front end side in the axial direction (thrust plate 32 side). It is rotatably mounted in the recess 28b in a slightly protruding state.

  On the other hand, the injection space 51 communicates with the outside via a circular injection hole 53 formed in a direction perpendicular to the axial direction of the worm shaft 28, and the injection space 51 is connected to the injection space 51 via the injection hole 53. A thermoplastic resin 54 made of a material different from that of the gear case 25 is injected at a predetermined pressure. When the molten resin 54 is injected into the injection space 51 from the injection hole 53, the thrust plate 32 is slid toward the proximal end side in the axial direction toward the worm shaft 28, and the axial direction of the thrust plate 32 via the steel balls 33 is performed. The end surface on the proximal end side is pressed against the end surface on the distal end side in the axial direction of the worm shaft 28. Then, by cooling and solidifying the resin 54 injected into the injection space 51, the thrust plate 32 is fixed in a point contact with the steel ball 33, and the axial direction front end side direction of the worm shaft 28 (rotating shaft 13). The thrust load is supported by the thrust plate 32.

  By adjusting the thrust of the worm shaft 28, formation of clearance (generation of play) between the end surface of the worm shaft 28 on the front end side in the axial direction and the gear case 25 (thrust plate 32) is prevented, and the worm 28a, the worm wheel 36, When the worm shaft 28 is reciprocated in the axial direction by the meshing, the end surface of the worm shaft 28 on the front end side in the axial direction collides with the gear case 25 and the generation of a hitting sound is suppressed.

  In the worm housing portion 26 of the gear case 25, an outer wall 55 formed in a substantially cylindrical shape so as to surround the injection hole 53 is perpendicular to the axial direction of the worm shaft 28, that is, between the center line C 1 of the injection hole 53 and the outer wall 55. It is formed so as to protrude in a direction parallel to the center line C2. At the time of resin injection into the injection space 51, the nozzle for resin injection is abutted against the end surface 55a on the opening side of the outer wall 55 to position the nozzle, and the resin 54 is the end surface on the opening side of the outer wall 55 as shown in FIG. Fill up to 55a.

  The worm housing portion 26 of the gear case 25 is formed with a cylindrical workpiece holding portion 56 that protrudes in the direction opposite to the outer wall 55. When the resin is injected into the injection space 51, the gear case 25 is in the workpiece holding portion 56. Resin injection is performed in a state where is held. In addition, the resin 54 injected into the injection space 51 is filled into the substantially rectangular recess 32a of the thrust plate 32, whereby the worm shaft 28 (steel ball 33) is rotated. The thrust plate 32 is prevented from rotating.

  As shown in FIG. 3, the injection hole 53 is eccentric in the axial direction of the worm shaft 28 in the direction away from the thrust plate 32 with respect to the center line C <b> 2 of the outer wall 55. The distance D is shifted. The eccentric distance D is set to be larger than the radius r of the injection hole 53, and the injection hole 53 is disposed in a region on the tip side in the axial direction from the center line C <b> 2 of the outer wall 55. That is, the injection hole 53 is disposed such that the side surface 53a on the axial base end side (thrust plate 32 side) is positioned on the axial front end side with respect to the center line C2 of the outer wall 55.

  5 (A) and 5 (B) are axial sectional views for comparing the comparative example and the thrust adjusting structure according to the present invention. As shown in FIG. 5 (A), in the thrust adjusting structure of the comparative example, the injection hole The center line C1 of 53 and the center line C2 of the outer wall 55 are formed to coincide with each other. In this case, in the cross section along the axial direction of the rotary shaft 13, the gear case 25 between the opening end a <b> 1 on the axial base end side (the thrust plate 32 side) of the outer wall 55 and the axial tip end a <b> 2 of the rotary shaft housing chamber 50. The minimum creepage distance L1 along the interface 58 with the resin 54 (indicated by a thick line in the figure) is the distance between the opening end a3 on the axially distal end side of the outer wall 55 and the axially distal end a4 of the rotary shaft accommodating chamber 50. The creepage distance L2 along the interface 59 (shown by a bold line in the figure) with the resin 54 is extremely small.

  On the other hand, as shown in FIG. 5 (B), in the thrust adjusting structure according to the present invention, the injection hole 53 has a direction in which the center line C1 is separated from the thrust plate 32 with respect to the center line C2 of the outer wall 54 (front end in the axial direction). ) By an eccentric distance D. In this case, the gear case 25 between the opening end b1 on the axial base end side (thrust plate 32 side) of the outer wall 55 and the axial front end b2 of the rotary shaft accommodating chamber 50 in the cross section along the axial direction of the rotary shaft 13 The minimum creepage distance M1 along the interface 60 with the resin 54 (indicated by a thick line in the figure) is larger than the minimum creepage distance L1 in the thrust adjustment structure of the comparative example (M1 = L1 + 2D).

  Thus, in the axial direction of the worm shaft 28 (rotating shaft 13), the injection hole 53 is arranged in a direction (axial front end side) in which the center line C1 is farther from the thrust plate 32 than the center line C2 of the outer wall 55. As a result, the minimum creepage distance M1 can be increased as compared with the case where the center line C1 of the injection hole 53 and the center line C2 of the outer wall 55 are formed to coincide with each other as in the thrust adjustment structure of the comparative example. The airtightness inside the gear case 25 can be improved. That is, since the interface distance M1 along the interface 60 between the gear case 25 and the resin 54 is increased, it is possible to prevent rainwater or the like from entering the gear case 25 along the interface 60.

  As shown in FIG. 5B, in the thrust adjustment structure according to the present invention, the gear case 25 and the resin between the opening end b3 on the axial front end side of the outer wall 55 and the axial front end b4 of the rotary shaft housing chamber 50 are provided. The creepage distance M2 along the interface 61 (shown by a bold line in FIG. 5) with the reference numeral 54 is smaller than the creepage distance L2 in the thrust adjustment structure of the comparative example (M2 = L2-2D), but the creepage distance M2 is the minimum creepage distance M1. Therefore, there is no possibility that the airtightness inside the gear case 25 is deteriorated.

  As shown in FIG. 4B, the outer wall 55 is integrally formed with a plurality of protrusions 63 that protrude from the inner peripheral surface 55b toward the center direction (inward in the radial direction) of the outer wall 55. Each protrusion 63 has an arcuate end surface 63a as a first end surface connected to the circular inner peripheral surface 55b of the outer wall 55, and is formed closer to the center side of the outer wall 55 than the arcuate end surface 63a. It has a substantially trapezoidal cross section with an arcuate end face 63b as a second end face facing toward the center of the cross section. A width E2 corresponding to the circumferential direction of the outer wall 55 in the arc-shaped end surface 63b of each protrusion 63 is formed to be larger than a width E1 corresponding to the circumferential direction of the outer wall 55 in the arc-shaped end surface 63a. A width corresponding to the circumferential direction of the outer wall 55 is increased from the inner peripheral surface 55b of 55 toward the center of the outer wall 55, that is, from the arc-shaped end surface 63a toward the arc-shaped end surface 63b. Further, as shown in FIG. 3, the axial height h of the outer wall 55 of each projection 63 is formed to be smaller than the axial height H of the outer wall 55. The resin 54 is easily filled between the circumferential directions.

  As shown in FIG. 5A, when the protrusion 63 is not provided on the inner peripheral surface 55b of the outer wall 55, the resin 54 heat-shrinks when the resin 54 is solidified, and the outer surface (outer wall of the resin 54 55) (surface facing the inner peripheral surface 55b of 55) warps toward the center of the outer wall 55. Thereby, a gap is generated at the interface between the outer wall 55 and the resin 54, and the airtightness inside the gear case 25 is deteriorated. On the other hand, as shown in FIG. 5B, when the protrusions 63 are provided on the outer wall 55, each protrusion 63 becomes a wedge even if the resin 54 is thermally contracted when the resin 54 is solidified. It is possible to suppress the outer surface of the resin 54 from warping toward the center of the outer wall 55. That is, since the width corresponding to the circumferential direction of the outer wall 55 in each protrusion 63 is formed to increase toward the center direction of the outer wall 55, the resin 54 filled between the circumferential directions of the protrusions 63 is formed on the outer wall. It is possible to suppress warping toward the center direction of 55. Therefore, it is possible to prevent a gap from being generated at the interface between the outer wall 55 and the resin 54, and to prevent deterioration of the airtightness inside the gear case 25.

  FIG. 6 is a sectional view in the axial direction showing a modification of the thrust adjusting structure according to the present invention. The injection hole 53 has a thrust plate whose center line C1 is in the axial direction of the worm shaft 28 with respect to the center line C2 of the outer wall 55. They are shifted by an eccentric distance D in a direction away from 32 (axial tip side direction). The eccentric distance D is set to be smaller than the radius r of the injection hole 53, and the injection hole 53 is arranged to extend from the axially distal end region to the axially proximal end region with respect to the center line C2 of the outer wall 55. ing. That is, the injection hole 53 is arranged such that the side surface 53a on the axial base end side (thrust plate 32 side) is located on the axial base end side with respect to the center line C2 of the outer wall 55.

  As described above, even when the side surface 53a on the axial base end side of the injection hole 53 is located on the axial base end side with respect to the center line C2 of the outer wall 55, the worm shaft 28 (rotating shaft 13) is not affected. In the axial direction, if at least the injection hole 53 is arranged such that the center line C1 is located on the tip side in the axial direction with respect to the center line C2 of the outer wall 55, the minimum creepage distance M1 can be increased, and the same effect as described above Can be played.

  FIG. 7 is an axial sectional view showing another modification of the thrust adjusting structure according to the present invention. The injection hole 53 has its center point O with respect to the center line C 2 of the outer wall 55 in the axial direction of the worm shaft 28. The center line C1 is inclined with respect to the center line C2 of the outer wall 55 by an inclination angle α at a position shifted by an eccentric distance D in a direction away from the thrust plate 32 (axial tip side direction). In this case, the center line C1 of the injection hole 53 is disposed so as to be inclined with respect to the center line C2 of the outer wall 55, and the injection hole 53 is axially extended from a region on the axial front end side with respect to the center line C2 of the outer wall 55. It is arranged across the region on the direction base end side. That is, the injection hole 53 is arranged such that the side surface 53a on the axial base end side (thrust plate 32 side) extends from the axial base end region to the axial base end region with respect to the center line C2 of the outer wall 55. ing.

  Thus, even if the injection hole 53 is formed with the center line C1 inclined with respect to the center line C2 of the outer wall 55, at least the injection in the axial direction of the worm shaft 28 (rotating shaft 13). If the hole 53 is arranged such that the center point O is closer to the front end side in the axial direction than the center line C2 of the outer wall 55, the minimum creepage distance M1 can be increased, and the same effect as described above can be obtained.

  It goes without saying that 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, in the above embodiment, the motor with the speed reduction mechanism of the present invention is applied to the power window motor 10 of the power window device that lifts and lowers the vehicle windshield, but the present invention is not limited to this. The present invention can also be applied to a drive source such as a wiper device or an electric sunroof device mounted on a vehicle.

  Further, in the embodiment, the injection hole 53 is formed in a circular shape, but the present invention is not limited to this, and may be formed in a rectangular shape, for example.

  Furthermore, in the above-described embodiment, the brushless DC motor is used as the electric motor 11, but the invention is not limited to this, and the rotating shaft 13 (the armature shaft 17 and the worm shaft 28) can rotate in both forward and reverse directions. If so, for example, a brushless electric motor may be used. In the above-described embodiment, the rotary shaft 13 has a split shaft structure including the armature shaft 17 and the worm shaft 28, but may be formed by a single shaft.

It is a partially cutaway top view of the power window motor which is one embodiment of the present invention. It is sectional drawing which follows the AA line in FIG. It is an expanded sectional view which follows the BB line shown in FIG. (A) is a disassembled perspective view of the thrust adjustment structure shown in FIG. 3, (B) is a C arrow view in (A). (A), (B) is an axial sectional view for comparing the comparative example and the thrust adjustment structure in the present invention. It is an axial direction sectional view showing the modification of the thrust adjustment structure in the present invention. It is an axial direction sectional view showing other modifications of the thrust adjustment structure in the present invention.

Explanation of symbols

10 Power window motor (motor with reduction mechanism)
DESCRIPTION OF SYMBOLS 11 Electric motor 12 Gear part 13 Rotating shaft 14 Motor case 14a Tube part 14b Stepped bottom part 14c Flange part 15 Permanent magnet 16 Rotor 17 Armature shaft 18, 19 Radial bearing 20 Thrust plate 21 Steel ball 22 Commutator 23 Brush holder 23a Brush 24 bolt 25 gear case 26 worm housing portion 26a worm housing chamber 28 worm shaft 29 coupling tool 30, 31 radial bearing 32 thrust plate 32a recess 33 steel ball 35 worm wheel housing portion 35a worm wheel housing chamber 35b bottom wall portion 35c cylindrical portion 36 worm Wheel 36a Tooth part 37 Support shaft 38 Bottom cover 39 Communication hole 40 Damper member 41 Drive plate 42 Output gear 43 Seal member 50 Rotating shaft accommodating chamber 51 Injection space 53 In hole 53a axial direction base end side of the side surface 54 resin 55 outer wall 55a end face 55b in the peripheral surface 56 work holder 58 to 61 interface 63 projecting 63a arcuate end surface (first end surface)
63b Arc-shaped end face (second end face)

Claims (5)

A rotary shaft housing chamber that houses the rotary shaft of the electric motor and an injection hole that opens in a direction perpendicular to the axial direction of the rotary shaft and communicates with the outside and is formed continuously with the rotary shaft housing chamber. A gear case in which an injection space is formed, and a thrust plate that is accommodated in the gear case and partitions the rotary shaft housing chamber and the injection space, and the rotary shaft is formed by injecting resin into the injection space. A motor with a speed reduction mechanism adapted to perform thrust adjustment of
The gear case is formed with a protruding outer wall surrounding the injection hole,
The motor with a speed reduction mechanism, wherein the injection hole is arranged in a direction in which the center of the injection hole is farther from the thrust plate than the center of the outer wall in the axial direction of the rotation shaft. The rotary shaft accommodating chamber that accommodates the rotating shaft of the electric motor and the injection hole that opens in the direction perpendicular to the axial direction of the rotating shaft communicate with the outside and are formed continuously with the rotating shaft accommodating chamber. A gear case in which an injection space is formed; and a thrust plate that is accommodated in the gear case and separates the rotary shaft housing chamber and the injection space, and the rotation is performed by injecting resin into the injection space. A motor with a speed reduction mechanism that adjusts the thrust of the shaft,
The gear case is formed with a protruding outer wall surrounding the injection hole,
The motor with a speed reduction mechanism, wherein the injection hole is arranged in a region on the direction side away from the thrust plate with respect to the center of the outer wall in the axial direction of the rotating shaft. A rotary shaft housing chamber that houses the rotary shaft of the electric motor and an injection hole that opens in a direction perpendicular to the axial direction of the rotary shaft and communicates with the outside and is formed continuously with the rotary shaft housing chamber. A gear case in which an injection space is formed, and a thrust plate that is accommodated in the gear case and separates the rotary shaft housing chamber and the injection space, and the rotation by injection of resin into the injection space A motor with a speed reduction mechanism that adjusts the thrust of the shaft,
The gear case is formed with a protruding outer wall surrounding the injection hole,
A side surface on the thrust plate side of the injection hole is disposed in a direction side away from the thrust plate with respect to the center of the outer wall in the axial direction of the rotation shaft. motor.   The motor with a speed reduction mechanism according to any one of claims 1 to 3, wherein a projection is formed on the outer wall from an inner peripheral surface of the outer wall toward a center direction of the outer wall. Motor with reduction mechanism.   5. The motor with a speed reduction mechanism according to claim 4, wherein the protrusion includes a first end surface coupled to an inner peripheral surface of the outer wall, and a second end formed in a center direction of the outer wall with respect to the first end surface. A motor with a speed reduction mechanism, characterized in that the first end surface and the second end surface are formed so that the width of the second end surface is larger than that of the first end surface. .

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