JP5414407B2 - Motor with reduction mechanism - Google Patents

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 gear case.

  For actuators such as wiper devices and power window devices mounted on vehicles such as automobiles, a motor with a speed reduction mechanism that uses an electric motor and a speed reduction mechanism as one unit is used. The motor with a speed reduction mechanism has 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, and the rotation of the electric motor is reduced. The output is decelerated by the mechanism.

  The motor with a speed reduction mechanism includes 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, and the worm and the worm wheel are connected to the gear case. It is engaged inside. Due to this meshing, a thrust load is applied to the rotating shaft of the electric motor, and a thrust plate for supporting the thrust load of the rotating shaft is provided inside the gear case. In such a thrust support structure, when there is a clearance between the axial end surface of the rotating shaft and the thrust plate, the rotating shaft is reciprocated in the axial direction by the thrust load, and the axial end surface of the rotating shaft is moved to the thrust plate. Collisions will generate abnormal noise.

  Therefore, for example, Patent Document 1 discloses a motor with a speed reduction mechanism that suppresses rattling of the rotating shaft by injecting resin into the gear case in order to prevent the generation of abnormal noise. In this motor with a speed reduction mechanism, the interior of the worm housing portion is partitioned by a thrust plate into a rotating shaft housing chamber in which the rotating shaft is housed, and an injection space that communicates with the outside through the injection hole. The thrust of the rotary shaft is adjusted by injecting resin into the injection space.

JP 2002-115716 A

  By the way, in such a thrust adjusting structure, a residual pressure remains in the thrust direction of the rotating shaft after resin injection, that is, a thrust load is always applied from the thrust plate to the rotating shaft. The drive efficiency of the motor will deteriorate. Therefore, it is preferable to increase the axial dimension of the injection space to increase the amount of thermal contraction in the axial direction of the resin due to cooling after resin injection, and to reduce the residual pressure in the thrust direction of the rotating shaft. However, if the axial dimension of the injection space is simply increased, the slidable range of the thrust plate before resin injection is increased, and the thrust plate may be inclined with respect to the axial direction of the rotary shaft. When the resin is poured in such a state that the thrust plate is inclined, the contact point between the thrust plate and the steel ball provided at the axial end of the rotating shaft is fixed in an eccentric state, and the rotating shaft operates. It will lead to the occurrence of defects and abnormal noise. In order to suppress the inclination of the thrust plate, it is conceivable to increase the thickness (axial dimension) of the thrust plate, but in that case, the gear case is rotated to ensure sufficient axial dimension of the injection space. It is necessary to increase the axial direction of the shaft, which increases the size of the gear case and deteriorates the layout.

  Also, if the slidable range of the thrust plate before resin injection becomes large, the steel ball fitted in the recess at the axial end of the rotating shaft falls off, or if the rotating shaft has a split shaft structure, the shaft connecting portion If the resin is injected as it is, malfunction of the rotating shaft and abnormal noise may occur.

  An object of the present invention is to restrict the slidable range of the thrust plate before resin injection to prevent malfunction of the rotating shaft and generation of abnormal noise.

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 that is received 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, wherein the thrust plate is disposed in a thrust plate housing chamber that slidably houses the thrust plate in the axial direction of the rotating shaft. are, the said injection space by the thrust plate is partitioned and formed in the thrust plate housing chamber, said injection space, said thrust Plate surface facing in the axial direction on the end face is provided for, the said facing surfaces, and a resin injection path for injecting resin into said injection space to extend in the thrust plate side, the axial direction of the rotary shaft An annular protrusion that protrudes from the surface is formed.

Reduction mechanism with the motor of the present invention, the injection space characterized in that it is communicated with the injection hole via the resin injection path formed in the injection space and coaxially.

Reduction mechanism with the motor of the present invention, the on opposing surfaces, a plurality of radial projections provided at equal intervals in the circumferential direction is formed, characterized in Rukoto.

In the motor with a speed reduction mechanism according to the present invention, the thrust plate has a recess formed on an end surface on the injection space side, and the annular protrusion is provided at a position facing the recess of the thrust plate. .

  In the motor with a speed reduction mechanism of the present invention, an outer wall surrounding the opening of the injection hole protrudes from the gear case, and the injection hole has an axial center of the injection hole in the axial direction of the rotation shaft. It arrange | positions in the direction away from the said thrust plate rather than the center, It is characterized by the above-mentioned.

  In the motor with a speed reduction mechanism according to the present invention, the outer wall has a first end surface connected 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 outer wall protrusion is provided so that the width of the second end face is larger than the width of the first end face.

  According to the present invention, since the projection that protrudes in the axial direction of the rotary shaft toward the thrust plate side is formed in the injection space, the thrust plate before resin injection is compared with the case where no projection is provided. The slidable range in the axial direction can be reduced. As a result, the thrust plate can be slid by the protrusion before the resin injection even when the axial dimension of the injection space is sufficiently secured so that the residual pressure applied to the rotating shaft after the resin injection can be reduced by thermal contraction of the resin. Is restricted, and the thrust plate is prevented from tilting. In addition, the steel ball fitted in the recess formed on the end surface on the axial front end side of the rotating shaft falls off from the recess, or when the rotating shaft has a split shaft structure, the connecting portion of the rotating shaft is disengaged. Is also prevented. Accordingly, the resin is not injected and the thrust plate is not fixed in a state where these problems occur, and it is possible to prevent malfunction of the rotating shaft and generation of abnormal noise.

  According to the present invention, since the annular protrusion is provided so as to extend the resin injection path to the thrust plate side, the resin injected from the resin injection path into the injection space at the time of resin injection is centered in the radial direction of the thrust plate. The thrust plate is prevented from being inclined with respect to the axial direction. In addition, the annular protrusion receives a biasing force in the radially inward direction on the outer peripheral surface thereof due to the thermal contraction of the resin, so that the inner periphery of the annular protrusion is applied to the outer peripheral surface of the resin injected into the resin injection path. The peripheral surface is pressed and the airtightness inside the gear case is improved.

  According to the present invention, since the projection is provided at a position facing the recess formed on the end surface on the injection space side of the thrust plate, the axial distance between the end surface of the annular projection and the end surface of the recess is the axis of the injection space. It can be set so as to have a substantially uniform distance with the directional dimension, and the amount of heat shrinkage of the resin can be made substantially uniform. Therefore, it is possible to effectively reduce the residual pressure applied to the rotating shaft, and it is possible to suppress the inclination of the thrust plate due to the uneven heat shrinkage of the resin.

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 sectional drawing which follows the BB line in FIG. (A) is an exploded perspective view of the thrust adjustment structure shown in FIG. 3, and (B) is a plan view showing a part of the gear case as seen from the direction of arrow C in FIG. 4 (A). It is sectional drawing of the gear case which follows the DD line | wire in FIG. (A), (B) is an axial sectional view for comparing the comparative example and the thrust adjustment structure in the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The power window motor 10 is provided in a power window device 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 rotary shaft 13 provided in the electric motor 11 can rotate in both forward and reverse directions. The electric motor 11 has a yoke 14 formed by press-forming a thin steel plate or the like into a stepped cylindrical shape with a bottom, and the inner surface of the yoke 14 has an N pole and an S pole facing radially inward. A pair of permanent magnets 15 magnetized to each other are fixed so as to oppose each other in the radial direction of the rotary shaft 13.

  Inside the yoke 14 is accommodated an armature (armature) 16 that faces each permanent magnet 15 via a minute gap (air gap). The armature 16 has an armature core 16a having a plurality of slots in the rotation direction, and a plurality of armature coils 16b are mounted on each slot of the armature core 16a by winding a conductive wire. An armature shaft 17 is provided through the shaft center of the armature 16, and the end of the armature shaft 17 on the axial base end side (left side in FIG. 1) is a radial fixed to the bottom wall of the yoke 14. The bearing 18 is rotatably supported. The end surface of the armature shaft 17 on the proximal side in the axial direction is in contact with a thrust plate 19 fixed to the bottom wall of the yoke 14 via a steel ball 20, and the armature shaft 17 (rotating shaft) is supported by the thrust plate 19. The thrust load in the axial direction proximal direction of 13) is supported. On the other hand, the end of the armature shaft 17 on the front end side in the axial direction is rotatably supported by a radial bearing 22 fixed to a resin brush holder 21 attached to the opening of the yoke 14.

  A commutator 23 that rotates integrally with the armature 16 is fixed to the armature shaft 17 adjacent to the axial front end side of the armature 16. The commutator 23 includes a plurality of segment pieces arranged at equal intervals in the rotation direction of the armature shaft 17 in a state of being insulated from each other, and a coil end of a corresponding armature coil 16b is electrically connected to each segment piece. Has been. A pair of brushes 21 a provided on the brush holder 21 are in sliding contact with the outer peripheral surface of the commutator 23.

  The electric motor 11 is attached to the gear case 25 of the gear portion 12 on the opening side of the yoke 14. The resin gear case 25 includes a worm housing portion 26 that extends in the axial direction of the armature shaft 17 and opens toward the yoke 14. The electric motor 11 is fixed to an end surface of the worm housing portion 26 on the opening side, and the armature The end of the shaft 17 on the front end side in the axial direction protrudes into a worm housing chamber 26 a formed inside the worm housing portion 26. A connector unit (not shown) for supplying power to the armature 16 of the electric motor 11 via the brush 21a and the commutator 23 is mounted in the opening 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 21 to connect an electric circuit that connects the power supply connector on the vehicle side and the armature coil 16b of the armature 16. The armature shaft 17 is rotated in the forward direction or the reverse direction when electric power is supplied to the electric motor 11 through this connector unit.

  An end portion on the axial base end side of the worm shaft 28 arranged coaxially with the armature shaft 17 is connected to the end portion on the axial end side of the armature shaft 17 protruding into the worm storage chamber 26a by a connector 29. The worm shaft 28 is rotated integrally with the armature shaft 17. 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 worm shaft 28 is accommodated in the worm accommodating chamber 26 a, and ends on both axial ends thereof are rotatably supported by radial bearings 30 and 31. Further, the end surface of the worm shaft 28 on the front end side in the axial direction is in contact with a thrust plate 32 disposed on the end portion on the front end side in the axial direction of the worm storage chamber 26 a via a steel ball 33. A thrust load in the axial tip side direction of the worm shaft 28 (rotating shaft 13) is supported. 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 36 a meshing with the worm 28 a is formed in the worm wheel housing chamber 35 a formed inside the worm wheel housing portion 35. A worm wheel 36 provided on the outer periphery 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 along the outer periphery of the support shaft 37 from the bottom wall portion 35 b of the worm wheel housing portion 35.

  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 and the tooth portion 36a of the worm wheel 36 are engaged with each other through a communication hole 39, and the rotation of the electric motor 11 is decelerated by a reduction mechanism including the worm 28a and the worm wheel 36. Has been transmitted.

  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 where 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 projecting from the bottom cover 38 to the outside of the worm wheel housing chamber 35a. The output gear 42 and the drive gear of the window regulator are engaged with each other so that the window regulator is driven. ing. A seal member 43 is attached to the inner surface of the bottom cover 38, 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 the power window motor 10, the thrust plate 32 is pressed against the end surface of the worm shaft 28 (rotary shaft 13) in the axial direction through the steel ball 33 by injecting resin into the gear case 25. There is provided a thrust adjustment structure for adjusting the thrust.

  FIG. 3 is a cross-sectional view taken along line BB in FIG. 1 and shows an axial cross-sectional view of a thrust adjustment structure provided in the power window motor 10. 4 (A) is an exploded perspective view of the thrust adjustment structure shown in FIG. 3, and FIG. 4 (B) is a plan view showing a part of the gear case as seen from the direction of arrow C in FIG. 4 (A). FIG. 5 is a cross-sectional view of the gear case taken along line DD in FIG.

  As shown in FIG. 3, this thrust adjusting structure is provided at the end of the worm housing portion 26 on the axial front end side. The end of the worm storage chamber 26a on the front end side in the axial direction has a stepped shape so that the diameter decreases toward the front end side in the axial direction. A thrust plate accommodation chamber 49 in which the thrust plate 32 is accommodated is formed. By this thrust plate 32, the worm storage chamber 26a is injected into the axially proximal end side rotary shaft storage chamber 50 in which the worm shaft 28 is stored, and the axially distal end side injection formed continuously with the rotary shaft storage chamber 50. A space 51 is partitioned in the axial direction.

  The thrust plate 32 has a metal disk shape having a diameter slightly smaller than the diameter of the thrust plate accommodating chamber 49, and the resin 52 injected into the injection space 51 is rotated from the injection space 51 side to the rotating shaft. In order to prevent leakage to the storage chamber 50 side, the thrust plate storage chamber 49 is slidable in the axial direction. The thickness (axial dimension) of the thrust plate 32 is large enough to prevent the thrust plate 32 from being inclined with respect to the axial direction. The end surface of the thrust plate 32 on the base end side in the axial direction (rotary shaft housing chamber 50 side) is provided with a receiving surface 32a that is recessed in the front end side in the axial direction and is formed in a plane perpendicular to the axial direction of the worm shaft 28. The steel ball 33 mounted on the end surface of the worm shaft 28 on the front end side in the axial direction can make point contact with the receiving surface 32a. Thus, even if the thickness of the thrust plate 32 is increased to prevent the thrust plate 32 from being inclined with respect to the axial direction by forming the receiving surface 32a in contact with the steel ball 33 in a concave shape, The end surface of the thrust plate 32 on the front end side in the axial direction is prevented from greatly protruding toward the injection space 51 side. Therefore, it is not necessary to enlarge the thrust plate accommodating chamber 49 in the axial direction in order to sufficiently secure the axial dimension of the injection space 51, and it becomes possible to prevent the gear case 25 from being enlarged and from being deteriorated in layout. As shown in FIG. 4A, a substantially hexagonal recess 32b is formed on the end surface of the thrust plate 32 in the axial direction front end side (injection space 51 side), and the injection space 51 is formed in the recess 32b. Communicating with

  The worm shaft 28 is accommodated in the rotating shaft accommodation chamber 50, and the worm shaft 28 is secured by a radial bearing 31 that is fixed in the rotating shaft accommodation chamber 50 adjacent to the axial base end side of the thrust plate accommodation chamber 49. The end part of the axial direction front end side 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 a steel ball 33 is partially in the recess 28 from the end surface on the front end side of the worm shaft 28 in the axial direction to the thrust plate 32 side. It is rotatably inserted in the protruding state. The end surface of the worm shaft 28 on the front end side in the axial direction is brought into contact with the receiving surface 32 a of the thrust plate 32 through the steel ball 33.

  On the other hand, the injection space 51 is defined by the thrust plate 32 in the thrust plate accommodating chamber 49 and includes a facing surface 51 a that faces the end surface of the thrust plate 32 on the front end side in the axial direction. The axial dimension L of the injection space 51 is such that the residual pressure applied to the worm shaft 28 after resin injection, that is, the thrust load constantly applied from the thrust plate 32 to the worm shaft 28 is caused by the thermal contraction of the resin 52 injected into the injection space 51. It is formed so large that it can be reduced. The injection space 51 communicates with a resin injection path 53 formed coaxially from the opposing surface 51 a to the tip end in the axial direction and having a smaller diameter than the injection space 51. The resin injection path 53 communicates with a circular injection hole 54 formed in a direction perpendicular to the axial direction of the worm shaft 28, and the injection space 51 passes through the injection hole 54 and the resin injection path 53. The gear case 25 communicates with the outside.

  A thermoplastic resin 52 made of a material different from that of the gear case 25 is injected into the injection space 51 with a predetermined pressure via an injection hole 54 and a resin injection path 53. When the molten resin 52 is injected into the injection space 51, the thrust plate 32 is slid toward the axially proximal end toward the axially distal end surface of the worm shaft 28, and the thrust plate 32 is interposed via the steel balls 33. The receiving surface 32a is pressed against the end surface of the worm shaft 28 on the front end side in the axial direction. Then, by cooling and solidifying the resin 52 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 tip side direction of the worm shaft 28 (rotating shaft 13). The thrust load is supported by the thrust plate 32. At this time, the resin 52 injected into the injection space 51 is filled up into the recess 32b of the thrust plate 32, and the rotation of the worm shaft 28 is caused by the solidification of the resin 52 filled in the recess 32b. Accordingly, the thrust plate 32 is prevented from rotating. The thrust adjustment of the worm shaft 28 prevents the formation of clearance between the steel ball 33 and the thrust plate 32 (generation of backlash), and the worm shaft 28 reciprocates in the axial direction by the engagement of the worm 28a and the worm wheel 36. It is suppressed that the steel ball 33 collides with the thrust plate 32 and generates abnormal noise.

  In this power window motor 10, in order to regulate the slidable range of the thrust plate 32 before resin injection, the axially proximal end side of the rotary shaft 13 faces the thrust plate 32 side toward the opposing surface 51 a of the injection space 51. A protruding annular protrusion 56 and a plurality of radial protrusions 57 are provided. The annular protrusion 56 is formed to have an inner diameter substantially equal to the diameter of the resin injection path 53, and is provided to face the recess 32 b of the thrust plate 32 so as to extend the resin injection path 53 to the thrust plate 32 side. The axial dimension of the annular protrusion 56 is such that the axial distance LA between the end face of the annular protrusion 56 on the distal end side in the axial direction and the end face of the recess 32 b of the thrust plate 32 is the opposite face 51 a of the injection space 51 and the thrust plate 32. The axial distance from the end face on the front end side in the axial direction, that is, the axial dimension L of the injection space is set to be substantially uniform.

  As shown in FIG. 5, three radial protrusions 57 protrude radially inward from the outer periphery of the injection space 51 and are provided at equal intervals in the circumferential direction. The axial dimension of the radial protrusion 57 is set to be approximately the same as the axial dimension of the annular protrusion 56. Further, the circumferential width dimension of the radial protrusions 57 is set to a small width dimension so as not to be affected by the thermal contraction of the resin 52.

  6A and 6B are axial cross-sectional views comparing the comparative example and the thrust adjustment structure of the present invention. In either case, the worm shaft 28 is applied to the worm shaft 28 due to the thermal contraction of the resin 52 after resin injection. The axial dimension L of the injection space 51 is set so that the residual pressure can be reduced. As shown in FIG. 6A, in the thrust adjustment structure of the comparative example, the protrusions 56 and 57 projecting toward the thrust plate 32 are not provided on the facing surface 51a of the injection space 51. In this case, in the stage before the resin 52 is injected, the thrust plate 32 has a position where the receiving surface 32 a comes into contact with the steel ball 33 and an end surface on the tip side in the axial direction comes into contact with the opposing surface 51 a of the injection space 51. It is possible to move between the positions over the entire length of the axial dimension L of the injection space 51 in the axial direction of the rotary shaft 13.

  On the other hand, as shown in FIG. 6 (B), in the thrust adjusting structure of the present invention, projections 56 and 57 projecting toward the thrust plate 32 are provided on the opposing surface 51a of the injection space 51. In this case, in the stage before the resin 52 is injected, the thrust plate 32 has a position where the receiving surface 32a abuts on the steel ball 33 and the end surface on the axial front end side is the axial base end side of the protrusions 56 and 57. It is possible to move within the slidable range LB (LB <L) in the axial direction of the rotary shaft 13 with respect to the position where it abuts against the end surface of the rotary shaft 13. That is, the axially distal end surface of the thrust plate 32 is brought into contact with the axially proximal end surfaces of the protrusions 56 and 57, whereby the slidable range of the thrust plate 32 is restricted by the protrusions 56 and 57. It is like that.

  In this manner, when the projections 56 and 57 projecting in the axial direction of the rotary shaft 13 toward the thrust plate 32 side are provided in the injection space 51, as shown in FIG. 6, when the projections 56 and 57 are not provided. In comparison, the slidable range of the thrust plate 32 before resin injection can be reduced. Thus, even when the axial dimension L of the injection space 51 is sufficiently secured so that the residual pressure applied to the worm shaft 28 after the resin injection can be reduced by the thermal contraction of the resin 52, the protrusions 56 and 57 can prevent the residual pressure before the resin injection. The slidable range of the thrust plate 32 is restricted, and the inclination of the thrust plate 32 is suppressed. Further, it is possible to prevent the steel ball 33 from dropping from the concave portion 28b of the worm shaft 28 or from disengaging the connecting portion 29 between the worm shaft 28 and the armature shaft 17. Accordingly, the resin 52 is not injected and the thrust plate 32 is not fixed in a state where these problems occur, and it is possible to prevent malfunction of the rotating shaft 13 and generation of abnormal noise.

  Further, since the annular protrusion 56 is provided so as to extend the resin injection path 53 to the thrust plate 32 side, the resin 52 injected from the resin injection path 53 into the injection space 51 is injected into the thrust plate 32 at the time of resin injection. It becomes easy to apply to the central portion in the radial direction, and the thrust plate 32 is suppressed from being inclined with respect to the axial direction. Further, the annular projection 56 receives a biasing force in the radially inward direction on the outer peripheral surface due to the thermal contraction of the resin 52, and thereby the annular protrusion 56 is annularly formed on the outer peripheral surface of the resin 52 injected into the resin injection path 53. The inner peripheral surface of the protrusion 56 is pressed and the airtightness inside the gear case 25 is improved.

  Further, since the annular protrusion 56 is provided at a position facing the recess 32 b of the thrust plate 32, the axial distance LA between the end surface on the axial base end side of the annular protrusion 56 and the end surface of the recess 32 b is the injection space 51. The axial dimension L can be set so as to be a substantially uniform distance, and the heat shrinkage amount of the resin 52 can be made substantially uniform. Therefore, the residual pressure applied to the rotary shaft 13 can be effectively reduced, and the thrust plate 32 can be prevented from being inclined due to the uneven heat shrinkage of the resin 52.

  In the present embodiment, the annular protrusion 56 and the radial protrusion 57 are provided, but it is needless to say that only one of them may be provided. The formation position and the number of the radial protrusions 57 are arbitrary. For example, four radial protrusions protruding radially outward from the outer peripheral surface of the annular protrusion 56 may be provided at equal intervals in the circumferential direction. However, it is preferable that the radial projections 57 are provided at equal intervals in the circumferential direction so as to receive the thrust plate 32 in a balanced manner, whereby the tilting of the thrust plate 32 can be suppressed.

  As shown in FIG. 3, an outer wall 60 formed in a substantially cylindrical shape so as to surround the injection hole 54 is formed in the worm housing portion 26 of the gear case 25, and a center line C <b> 1 of the injection hole 54 and a center line C <b> 2 of the outer wall 60. Are formed so as to protrude in a direction perpendicular to the axial direction of the worm shaft 28. At the time of resin injection into the injection space 51, the nozzle for resin injection is abutted against the end surface 60a on the opening side of the outer wall 60 to position the nozzle, and the resin 52 is the end surface on the opening side of the outer wall 60 as shown in FIG. Fill up to 60a. The worm housing portion 26 of the gear case 25 is formed with a cylindrical work holding portion 61 that protrudes in the direction opposite to the outer wall 60. When the resin is injected into the injection space 51, the gear case 25 is in the work holding portion 61. Resin injection is performed in a state where is held.

  As shown in FIG. 3, the injection hole 54 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 60. The distance D is shifted. The eccentric distance D is set to be larger than the radius r of the injection hole 54, and the injection hole 54 is arranged in a region on the tip side in the axial direction from the center line C <b> 2 of the outer wall 60. That is, the injection hole 54 is disposed such that the side surface 54a on the axial base end side (thrust plate 32 side) is positioned on the front end side in the axial direction with respect to the center line C2 of the outer wall 60.

  As shown in FIG. 6A, in the thrust adjustment structure of the comparative example, the center line C1 of the injection hole 54 and the center line C2 of the outer wall 60 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 (thrust plate 32 side) of the outer wall 60 and the axial tip end a <b> 2 of the rotary shaft housing chamber 50. The minimum creepage distance L1 along the interface 63 with the resin 52 (indicated by the bold line in the figure) is the distance between the opening end a3 on the axially distal end side of the outer wall 60 and the axially distal end a4 of the rotary shaft accommodating chamber 50. The creepage distance L2 along the interface 64 with the resin 52 (indicated by a bold line in the figure) is extremely small.

  On the other hand, as shown in FIG. 6B, in the thrust adjusting structure according to the present invention, the injection hole 54 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 60 (the axial front end side). ) By an eccentric distance D. In this case, in the cross section along the axial direction of the rotating shaft 13, the gear case 25 between the opening end b <b> 1 on the axial base end side (thrust plate 32 side) of the outer wall 60 and the axial tip b <b> 2 of the rotating shaft housing chamber 50. The minimum creepage distance M1 along the interface 65 (shown by a thick line in the figure) with the resin 52 is larger than the minimum creepage distance L1 in the thrust adjustment structure of the comparative example.

  Thus, in the axial direction of the worm shaft 28 (rotating shaft 13), the injection hole 54 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 60. 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 54 and the center line C2 of the outer wall 60 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 minimum creepage distance M1 along the interface 65 between the gear case 25 and the resin 52 is increased, it is possible to prevent rainwater or the like from entering the gear case 25 along the interface 65. Further, as shown in FIG. 6, even when the axial dimension L of the injection space 51 is sufficiently secured so that the residual pressure applied to the worm shaft 28 after resin injection can be reduced by the thermal contraction of the resin 52, the worm shaft 28 In the axial direction, the center line C1 of the injection hole 54 is arranged in a direction farther away from the thrust plate 32 than the center line C2 of the outer wall 60, so that the outer wall 60 is prevented from approaching the front end side in the axial direction of the rotary shaft 13. Therefore, the enlargement of the gear case 25 and the deterioration of the layout can be prevented.

  Further, since the annular protrusion 56 protruding toward the thrust plate 32 side is provided so as to extend the resin injection path 53, as shown in FIG. 6B, the outer wall 60 of the outer wall 60 in the cross section along the axial direction of the rotary shaft 13 is provided. The minimum creepage distance M1 along the interface 65 between the gear case 25 and the resin 52 between the opening end b1 on the base end side in the axial direction and the tip end b2 in the axial direction of the rotary shaft accommodating chamber 50 is further increased, and the airtightness inside the gear case 25 is increased. Has been improved.

  In the above embodiment, the eccentric distance D between the center line C1 of the injection hole 54 and the center line C2 of the outer wall 60 is set larger than the radius r of the injection hole 54, but the present invention is not limited to this. The center line C1 of 54 may be on the side away from the thrust plate 32 in the axial direction of the worm shaft 28 with respect to the center line C2 of the outer wall 60. Further, as shown in FIG. 6B, in the thrust adjusting structure according to the present invention, the gear case 25 and the resin between the opening end b3 on the axially distal end side of the outer wall 60 and the axially distal end b4 of the rotary shaft accommodating chamber 50 are disposed. The creepage distance M2 along the interface 66 (shown by a bold line in FIG. 5) with 52 is smaller than the creepage distance L2 in the thrust adjustment structure of the comparative example, but the creepage distance M2 is set larger than the minimum creepage distance M1. Therefore, there is no possibility that this will cause deterioration of the airtightness inside the gear case 25.

  As shown in FIG. 4B, the outer wall 60 is integrally formed with a plurality of outer wall protrusions 68 that protrude from the inner peripheral surface 60b toward the center direction (inward in the radial direction) of the outer wall 60. Each outer wall projection 68 has an arcuate end surface 68a as a first end surface connected to the circular inner peripheral surface 60b of the outer wall 60, and is formed on the outer wall 60 in the center direction side of the arcuate end surface 68a. 60 has a substantially trapezoidal cross section including an arcuate end surface 68b as a second end surface facing toward the center direction of 60. A width E2 corresponding to the circumferential direction of the outer wall 60 in the arc-shaped end surface 68b of each outer wall projection 68 is formed larger than a width E1 corresponding to the circumferential direction of the outer wall 60 in the arc-shaped end surface 68a. The width corresponding to the circumferential direction of the outer wall 60 increases from the inner peripheral surface 60b of the outer wall 60 toward the center of the outer wall 60, that is, from the arc-shaped end surface 68a toward the arc-shaped end surface 68b. . Further, as shown in FIG. 3, the axial height dimension h of the outer wall 60 in each outer wall protrusion 68 is formed smaller than the axial height dimension H of the outer wall 60. The resin 52 is easily filled between the circumferential directions of the outer wall protrusions 68.

  As shown in FIG. 6A, when the outer wall protrusion 68 is not provided on the inner peripheral surface 60b of the outer wall 60, the resin 52 is thermally contracted when the resin 52 is solidified, and the outer surface ( The surface facing the inner peripheral surface 60 b of the outer wall 60 is warped toward the center of the outer wall 60. Thereby, a gap is generated at the interface between the outer wall 60 and the resin 52, and the airtightness inside the gear case 25 is deteriorated. On the other hand, as shown in FIG. 6B, when the outer wall projection 68 is provided on the outer wall 60, each outer wall projection 68 is wedged even when the resin 52 is thermally contracted when the resin 52 is solidified. Thus, the outer surface of the resin 52 can be prevented from warping toward the center of the outer wall 60. That is, since the width corresponding to the circumferential direction of the outer wall 60 in each outer wall projection 68 is formed to increase toward the center direction of the outer wall 60, the resin 52 filled between the circumferential directions of each outer wall projection 68. Can be prevented from warping toward the center of the outer wall 60. Therefore, a gap is suppressed from being generated at the interface between the outer wall 60 and the resin 52, and deterioration of the airtightness inside the gear case 25 can be prevented.

  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. Moreover, in the said embodiment, although the injection hole 54 was formed circularly, it is not limited to this, For example, you may make it form in a rectangular shape.

  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.

10 Power window motor (motor with reduction mechanism)
DESCRIPTION OF SYMBOLS 11 Electric motor 12 Gear part 13 Rotating shaft 14 Yoke 15 Permanent magnet 16 Armature 16a Armature core 16b Armature coil 17 Armature shaft 18 Radial bearing 19 Thrust plate 20 Steel ball 21 Brush holder 21a Brush 22 Radial bearing 23 Commutator 25 Gear case 26 Warm accommodating part 26a Worm housing chamber 28 Worm shaft 28a Worm 28b Recess 29 Joint 30, 31 Radial bearing 32 Thrust plate 32a Receiving surface 32b Recess 33 Steel ball 35 Warm wheel housing 35a Worm wheel housing 35b Bottom wall 35c Cylindrical part 36 Warm wheel 36a Tooth part 37 Support shaft 38 Bottom cover 39 Communication hole 40 Damper member 41 Drive plate 42 Output gear 43 49 Thrust member 49 Thrust plate storage chamber 50 Rotating shaft storage chamber 51 Injection space 51a Opposing surface 52 Resin 53 Resin injection path 54 Injection hole 54a Side surface 56 Annular projection 57 Radial projection 60 Outer wall 60a End surface 60b Inner peripheral surface 61 Work holding portion 63 66 Interface 68 Outer wall projection 68a Arc-shaped end face (first end face)
68b Arc-shaped end face (second end face)

Claims (6)

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 divides the rotary shaft housing chamber and the injection space, and the thrust adjustment of the rotary shaft is performed by injecting resin into the injection space A motor with a speed reduction mechanism,
The thrust plate is disposed in a thrust plate housing chamber that slidably houses the thrust plate in the axial direction of the rotating shaft,
The injection space is defined by the thrust plate in the thrust plate storage chamber,
The injection space is provided with an opposing surface facing the end surface of the thrust plate from the axial direction, and a resin injection path for injecting resin into the injection space is extended to the thrust plate side on the opposing surface. A motor with a speed reduction mechanism , wherein an annular protrusion protruding in the axial direction of the rotating shaft is formed. In the motor with speed reduction mechanism of claim 1, wherein the motor with speed reduction mechanism the injection space, characterized in that it is communicated with the injection hole via the resin injection path formed in the injection space and coaxially. According to claim 1 or 2 motor with speed reduction mechanism, wherein the facing surface, a plurality of radial projections provided at equal intervals in the circumferential direction is formed a motor-equipped reduction mechanism, characterized in Rukoto. The motor with a speed reduction mechanism according to any one of claims 1 to 3, wherein the thrust plate has a recess formed on an end surface on the injection space side, and the annular protrusion faces the recess of the thrust plate. A motor with a speed reduction mechanism, wherein the motor is provided at a position where   5. The motor with a speed reduction mechanism according to claim 1, wherein an outer wall surrounding the opening of the injection hole is formed to protrude from the gear case, and the injection hole is formed in an axial direction of the rotation shaft. A motor with a speed reduction mechanism, wherein the center of the injection hole is disposed in a direction away from the thrust plate than the center of the outer wall.   6. The motor with a speed reduction mechanism according to claim 5, wherein the outer wall includes a first end surface connected to an inner peripheral surface of the outer wall, and a second end formed in the center direction of the outer wall from the first end surface. An outer wall projection provided with an end surface of the first end surface is provided, and the outer wall projection is formed so that the width of the second end surface is larger than the width of the first end surface.

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