JP4255864B2 - Thrust adjustment method for motor shaft and thrust bearing position adjustment method - Google Patents

Description

  The present invention relates to a method for adjusting the thrust of a motor shaft and a method for adjusting the position of a thrust bearing, which are suitable for use, for example, in an armature shaft of a wiper motor for rear window glass.

  As this type of motor shaft thrust adjustment structure, there is one shown in FIGS. 5 to 10 (see, for example, Patent Document 1). As shown in FIG. 5, the motor shaft 1 is used for a wiper motor M of an automobile, and its tip 1a is rotated by a synthetic resin thrust bearing 4 press-fitted into a bearing housing recess 3 of the gear case 2. It is supported freely.

  As shown in FIGS. 6 to 7, the motor shaft 1 is assembled in the gear case 2 with the thrust bearing 4 being in contact with the tip 1 a of the motor shaft 1, with both sides of the thrust bearing 4 being attached to the gear case 2. This is performed by fitting between the protrusions 3a for preventing slip formed on the opposite inner walls of the bearing housing recess 3 without retreating. At this time, both sides of the narrow lower portion 4a of the thrust bearing 4 are press-fitted between the anti-slip protrusions 3b formed on the narrow inner walls of the bearing housing recess 3, so that the thrust bearing 4 is more firmly fitted. It is like that.

  Note that a worm 1 b that meshes with the worm wheel 5 is formed at a position near the tip 1 a of the motor shaft 1. The opening 2 a of the gear case 2 is covered with a lid 6.

Japanese Utility Model Publication No.54-41880

  However, in the conventional thrust adjusting structure of the motor shaft 1, the thrust bearing 4 is simply pressed against the tip 1a of the motor shaft 1 and press-fitted to adjust the thrust without play of the thrust of the motor shaft 1. Therefore, when the length of the motor shaft 1 varies, skill is required for thrust adjustment, and it is impossible to maintain a constant thrust load and thrust amount in all the wiper motors M to be assembled.

  Therefore, the present invention has been made to solve the above-described problems, and it is possible to easily maintain a constant thrust load and thrust amount even if the length of the motor shaft varies. It aims to provide a method.

  According to a first aspect of the present invention, in the method for adjusting the thrust of the motor shaft, wherein the thrust of the motor shaft is adjusted by pressing the thrust bearing against the tip of the motor shaft, the lower portion of the thrust bearing is placed on the motor shaft while rotating the motor shaft. The thrust bearing is pushed with a predetermined load in the direction of the base end of the motor shaft in a state temporarily applied to the tip of the motor shaft, and then has a step from the lower portion of the thrust bearing while holding the temporarily pressed state. The upper part retracted is applied to the tip of the motor shaft, and the motor shaft is returned by the amount of the step through the biasing means.

  A second aspect of the present invention is the motor shaft thrust adjusting method according to the first aspect, wherein the motor shaft is used as an armature shaft of a wiper motor for a rear window glass.

  The invention of claim 3 is a thrust bearing position adjusting method for positioning a thrust bearing abutted against a tip of a motor shaft of a motor in a case in which the motor is accommodated, wherein the thrust bearing has a substantially rectangular parallelepiped shape. And an upper portion that serves as the thrust bearing, and a lower portion that is connected to the upper portion and protrudes by a predetermined thickness from the upper portion that serves as the thrust bearing. The case is formed narrower than the width, and the case is formed with a thrust bearing housing recess having a plurality of protrusions into which the upper portion of the thrust bearing is press-fitted and a housing portion in which the lower portion of the thrust bearing is housed. The thrust bearing is inserted into a thrust bearing housing recess, and an upper portion of the thrust bearing is disposed close to the plurality of protrusions, and the lower portion of the thrust bearing is To the motor shaft, a predetermined load is applied to the thrust bearing, the motor shaft is pushed, and then the thrust bearing is pushed in a direction perpendicular to the motor shaft so that the lower portion of the thrust bearing is The upper side surface of the thrust bearing is press-fitted into the plurality of protrusions until it is stored in the storage portion.

  As described above, according to the first aspect of the present invention, the thrust bearing is predetermined in the direction of the base end of the motor shaft while the lower portion of the thrust bearing is temporarily applied to the tip of the motor shaft while rotating the motor shaft. Pushing with a load, and then holding the temporarily pressed state, the upper part that has been stepped back from the lower part of the thrust bearing is applied to the tip of the motor shaft, and the motor shaft is stepped through the biasing means. By returning by the amount, thrust play can be easily made on the motor shaft by the level difference between the lower and upper portions of the thrust bearing. Thereby, even if the length of the motor shaft varies, a constant thrust load and a thrust amount can be easily maintained, and a high-precision motor can be assembled at a low cost.

  According to the invention of claim 2, the same effect as that of the invention of claim 1 can be obtained for the wiper motor for rear window glass.

  According to the invention of claim 3, even if the length of the motor shaft of the motor varies, the thrust bearing can be easily assembled by positioning and adjusting the thrust bearing housing recess of the case in which the motor is housed.

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

  1 is a cross-sectional view showing a wiper motor according to an embodiment of the present invention, FIG. 2 (a) is a cross-sectional view taken along line AA in FIG. 1 before a thrust bearing is attached, and FIG. 2 (b) is the same. 1 is a cross-sectional view taken along the line EE in FIG. 1 before mounting the thrust bearing, FIG. 3A is a cross-sectional view taken along the line A-A in FIG. 1 during the mounting of the thrust bearing, and FIG. 1 is a cross-sectional view taken along the line EE in FIG. 1 during the installation of the thrust bearing, FIG. 4A is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 4B is a cross-sectional view taken along the line EE in FIG. It is sectional drawing which follows.

  As shown in FIG. 1, a wiper motor 10 for a rear window glass of an automobile includes a substantially cylindrical yoke (motor case) 11 opened at one end side, and a flange portion 11b around an open end 11a of the yoke 11 with screws 13 And a die-cast gear case 12 fastened and fixed via A pair of magnets 14 and 14 are fixed to the inner peripheral surface 11c of the yoke 11 with an adhesive or the like. The armature shaft (motor shaft) 16 is rotatably supported by the bearing 15a fitted to the bottomed cylindrical portion 11d at the other end of the yoke 11 and the bearing 15b fitted to the shaft hole 12a of the gear case 12. It is.

  The armature shaft 16 has a worm 17 formed in the vicinity of its tip 16a. The steel ball 16 c embedded in the base end 16 b of the armature shaft 16 is in contact with a thrust plate 18 fitted into the bottomed cylindrical portion 11 d of the yoke 11 via a rubber damper (biasing means) 19. Furthermore, the tip 16a of the armature shaft 16 is in contact with a thrust bearing 20 that is press-fitted into a thrust bearing housing recess 12b that communicates with the shaft hole 12a of the gear case 12.

  As shown in FIGS. 1 to 4, the thrust bearing 20 is formed in a substantially rectangular parallelepiped shape from a synthetic resin, and the front and rear surfaces 20 a and 20 a thereof are receiving surfaces that press the spherical tip 16 a of the armature shaft 16. ing. Lower portions 20b of the front and rear surfaces 20a and 20a of the thrust bearing 20 protrude outward from the upper portion 20c in steps. The amount (thickness) of the step is indicated by the symbol t in FIGS. 2 (a) and 4 (a). Further, both side surfaces of the thrust bearing 20 have three step surfaces 20d, 20e, and 20f that become narrower toward the lower side. A recess 20g for inserting the pressing jig 30 is formed at the center of the upper surface of the thrust bearing 20.

  Further, as shown in FIGS. 2A and 2B, a plurality of anti-slip protrusions 12c are integrally formed at the center of opposite side walls of the thrust bearing housing recess 12b in which the thrust bearing 20 is housed. It is. The width between the plurality of protrusions 12c and 12c is formed to be smaller than the width between the central step surfaces 20e and 20e on both side surfaces of the thrust bearing 20, and the step surfaces 20e and 20e are pressed against the protrusions 12c and 12c. The thrust bearing 20 is held in the gear case 12 by being press-fitted. Further, the lower side of the opposite side walls of the thrust bearing housing recess 12b is a housing portion 12d in which the step surfaces 20f, 20f below the both side surfaces of the thrust bearing 20 are housed.

  An armature 21 is attached to a position of the armature shaft 16 facing the pair of magnets 14 and 14. The armature 21 is composed of an armature core 21a fixed to the armature shaft 16 and having a coil winding portion 21b having a predetermined number of slots, and an armature coil 21c wound around the coil winding portion 21b of the armature core 21a. Has been.

  Further, a commutator 22 is fixed at a position facing the boundary between the yoke 11 and the gear case 12 of the armature shaft 16. The commutator 22 includes the same number of commutator pieces 22a as the coil winding portion 21b of the armature core 21a, and each commutator piece 22a and the armature coil 21c are electrically connected to each other.

  Furthermore, the opening end of the shaft hole 12a of the gear case 12 is a large-diameter hole portion 12e, and a pair of brushes 24, 24 are interposed via a holder 23 at positions facing the commutator 22 in the large-diameter hole portion 12e. Is attached so as to contact the commutator piece 22a. Each brush 24 is electrically connected to a motor control circuit (not shown). When the wiper operation switch of the motor control circuit is switched from OFF to ON, a current flows through the armature 21 and the armature shaft 16 rotates.

  Further, a concave reduction mechanism housing portion 12f communicating with the shaft hole 12a is formed at the approximate center of the gear case 12. A worm wheel 25 meshed with the worm 17 of the armature shaft 16 is rotatably housed in the speed reduction mechanism housing portion 12f. The worm 17 and the worm wheel 25 constitute a speed reduction mechanism.

  Next, a procedure for adjusting the thrust of the armature shaft 16 by pressing the thrust bearing 20 against the spherical tip 16a of the armature shaft 16 in the wiper motor 10 having the above configuration will be described.

  First, the armature 21 and the yoke 11 are assembled in the gear case 12, and the armature shaft 16 is rotated. Next, as shown in FIGS. 2A and 2B, while the armature shaft 16 is rotated, the thrust bearing 20 is temporarily inserted into the thrust bearing housing recess 12b of the gear case 12, and the step surface 20e is formed into the protrusion 12c. Place close to.

  Next, as shown in FIGS. 3 (a) and 3 (b), the lower portion 20 b of the thrust bearing 20 is temporarily applied to the tip 16 a of the armature shaft 16, and the thrust bearing 20 is inserted into the thrust bearing 20 via the pressing jig 30. Push in the middle X direction (the direction of the base end 16b of the armature shaft 16) with an appropriate load. At this time, the thrust plate 18 slides in the X direction. Further, as shown in FIG. 1, the bottomed cylindrical portion 11 d of the yoke 11 is fixed by a fixing jig 31 so that the wiper motor 10 itself does not move.

  Next, while maintaining the above-described state in which the lower portion 20b of the thrust bearing 20 is temporarily pressed against the tip 16a of the armature shaft 16, as shown in FIGS. The upper part 20c which is press-fitted in a direction (a direction orthogonal to the motor shaft) via the pressing jig 30 and has a step t from the lower part 20b of the thrust bearing 20 is applied to the tip 16a of the armature shaft 16. At this time, the armature 21 is kept rotating. Due to the step t provided on the front surface 20 a of the thrust bearing 20, the armature shaft 16 is returned in the Y direction by the amount of the step t through the biasing force of the rubber damper 19. The return margin of the armature shaft 16 is maintained at an appropriate load by the reaction force of the rubber damper 19.

  Next, it is confirmed that the value of the current flowing through the armature coil 21c of the armature 21 is stable, and the rotation of the armature shaft 16 is stopped, whereby the thrust adjustment of the armature shaft 16 is completed.

  In this manner, the thrust bearing 20 is moved in the direction of the base end 16b of the armature shaft 16 (X direction) in a state where the lower portion 20b of the thrust bearing 20 is temporarily brought into contact with the tip 16a of the armature shaft 16 while rotating the armature shaft 16. The armature shaft 16 is pushed in with a predetermined load, and then the upper portion 20c retracted with a step t from the lower portion 20b of the thrust bearing 20 is applied to the tip end 16a of the armature shaft 16 while maintaining the temporarily pressed state. By returning the amount of the step t through the rubber damper 19, the play of the thrust can be easily made on the armature shaft 16 by the step t of the lower portion 20b of the thrust bearing 20 and the upper portion 20c. Thereby, even if the length of the armature shaft 16 varies, a constant thrust load and a thrust amount can be easily maintained, and the highly accurate wiper motor 10 can be assembled at a low cost.

  The play in the thrust direction of the armature shaft 16 can be easily changed by preparing in advance a plurality of thrust bearings in which the amount of the level difference t between the lower portion 20b and the upper portion 20c of the thrust bearing 20 is changed.

  According to the embodiment, the urging means for returning the armature shaft by the step is the rubber damper, but other urging means such as a leaf spring may be used. Of course, the embodiment can be applied to a motor other than a wiper motor for a rear window glass of an automobile.

It is sectional drawing which shows the wiper motor of one Embodiment of this invention. (A) is sectional drawing which follows the AA line in FIG. 1 before attaching a thrust bearing, (b) is sectional drawing which follows the EE line in FIG. 1 before attaching the same thrust bearing. (A) is sectional drawing in alignment with the AA line in FIG. 1 in the middle of attaching a thrust bearing, (b) is sectional drawing in alignment with the EE line in FIG. 1 in the middle of attaching the thrust bearing. (A) is sectional drawing which follows the AA line in FIG. 1, (b) is sectional drawing which follows the EE line in FIG. It is a top view of the wiper motor of a prior art example. FIG. 6 is an enlarged view of a portion E in FIG. 5. It is sectional drawing which follows the FF line in FIG. It is sectional drawing which follows the GG line in FIG. It is a perspective view of the principal part of the gear case used for the said prior art example. It is a perspective view of the thrust bearing used for the said prior art example.

Explanation of symbols

10 Wiper motor (motor)
12 Gear case (case)
12b Thrust bearing housing recess 12c Protrusion 12d Housing 16 Armature shaft (motor shaft)
16a tip 16b base 19 rubber damper (biasing means)
20 Thrust bearing 20b Lower part 20c Upper part X Direction of the base end of the motor shaft Z Direction perpendicular to the motor shaft t Step amount

Claims (3)

In the method for adjusting the thrust of the motor shaft, the thrust bearing is pressed against the tip of the motor shaft to adjust the thrust of the motor shaft.
While rotating the motor shaft, with the lower part of the thrust bearing temporarily applied to the tip of the motor shaft, the thrust bearing is pushed with a predetermined load in the direction of the base end of the motor shaft,
Next, while maintaining the state of pressing, the upper part of the thrust bearing that has been stepped back from the lower part of the thrust bearing is applied to the tip of the motor shaft, and the amount of the step through the biasing means. A method for adjusting the thrust of a motor shaft, characterized by performing minute return. A method of adjusting a thrust of a motor shaft according to claim 1,
A motor shaft thrust adjusting method, wherein the motor shaft is used as an armature shaft of a wiper motor for rear window glass. A thrust bearing position adjusting method for positioning a thrust bearing abutting on a tip of a motor shaft of a motor in a case in which the motor is accommodated,
The thrust bearing is formed in a substantially rectangular parallelepiped shape, and includes an upper portion serving as the thrust bearing and a lower portion connected to the upper portion and projecting by a predetermined thickness from the upper portion serving as the thrust bearing. The width is formed narrower than the width of the upper side surface,
The case is formed with a plurality of protrusions into which the upper part of the thrust bearing is press-fitted and a thrust bearing housing recess having a housing part in which the lower part of the thrust bearing is housed.
The thrust bearing is inserted into a thrust bearing housing recess, and the upper portion of the thrust bearing is disposed close to the plurality of protrusions,
The lower part of the thrust bearing is brought into contact with the motor shaft, a predetermined load is applied to the thrust bearing, and the motor shaft is pushed,
Next, the thrust bearing is pressed in a direction perpendicular to the motor shaft, and the upper side surface of the thrust bearing is press-fitted into the plurality of protrusions until the lower portion of the thrust bearing is accommodated in the accommodating portion. Thrust bearing position adjustment method characterized by

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