JP2011147227A - Motor with reduction gear, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably fix a motor housing, an end bell, and a gear box of a reduction gear portion without special change to the design of a method for fixing the end bell to the motor housing. <P>SOLUTION: The end bell made of resin is fitted to an opening of the motor housing and an rotating shaft penetrating the end bell with a bearing housed therein is extended into the reduction gear portion. The reduction gear portion includes the gear box made of resin for housing a worm fixed on the rotating shaft and a helical gear engaged therewith. A stepped portion in the resin gear box is opposed to one side of an end bell flange portion in the direction of the axis of the shaft. Multiple integrally molded projections are provided on the surface of either of the end bell and the gear box opposed to each other. These projections are pressed against the surface of the other of the end bell and the gear box opposed to each other and the gear box is fixed to the motor housing. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a motor with a speed reducer configured by integrally assembling a motor part and a speed reducer part, and a method for manufacturing the same, and in particular, a connection between a motor housing attached by fitting an end bell in an opening and a resin gear case. Concerning configuration.

  The motor with a reduction gear is configured by assembling a motor portion and a reduction gear portion integrally. The reduction gear unit houses a worm connected to the rotating shaft and a worm wheel meshing with the worm in the gear box. When the motor of the motor unit is driven, the rotation shaft rotates, and this rotation rotates the worm wheel at a reduced speed via the worm.

  The rotating shaft of such a motor with a reduction gear is supported by a total of three or four bearings, and each bearing is provided on a different member. That is, the rotary shaft is supported by a bearing provided with one motor housing, one end bell fitted into the opening, and one or two gearboxes. For this reason, unless the motor housing provided with each bearing, the end bell, and the gear box are attached to each other with high accuracy, the bearing position changes and cannot be adjusted to the intended alignment. As a result, there is a case in which abnormal noise occurs due to deviation from the target alignment.

  8A and 8B are diagrams showing a fixing structure of the motor housing and the end bell disclosed in Patent Document 1, FIG. 8A is a side view of the motor housing, and FIG. 8B is a front view of the end bell fixed to the opening. (C) is a side sectional view of the motor after assembly. The end bell is fixed to the opening of the motor housing. This end bell has a mounting surface as a butt end surface facing the mounting surface on the motor housing opening side, and is fixed to the motor housing by crimping a plurality of claws formed protruding from the opening of the motor housing. Has been. A plurality of small protrusions are formed on the mounting surface on the end bell side. Each of these small protrusions is in contact with the mounting surface on the motor housing side, and in this state, the end bell is fixed to the motor housing. These small protrusions correct the mating surface when the motor housing and the end bell are abutted and fixed. This prevents the mating surface from being inclined with respect to the axis of the motor output shaft.

  Thus, the motor disclosed in Patent Document 1 prevents the mating surface from being inclined with respect to the axis of the motor output shaft by the small protrusion provided on the mounting surface on the end bell side when the end bell and the motor housing are fixed by caulking. However, for caulking, it is necessary to bend the tip of a small nail and hold down the end bell. For this reason, for example, a motor with a high output specification (motor with a speed reducer) with a housing thickness of 0.5 mm or more is required. It is practically difficult to apply, and it is disadvantageous in terms of cost as compared with a normal fixing method in which an end bell is simply press-fitted and fitted.

Japanese Patent No. 3200348

  In a normal motor, a resin end bell is fitted into an opening of a metal motor housing by press fitting. When such a motor is used as a motor with a speed reducer that repeats forward rotation and reverse rotation, a load is applied to the worm provided at the tip of the rotation shaft and the helical gear meshing with the worm, and the rotation shaft bends. Become. As a result, the end bell attached with the bearings is lifted from the motor housing, and the alignment between the bearings cannot be maintained. The present invention has been made by discovering such a phenomenon. In order to solve such a problem, it is conceivable to firmly fix the end bell to the motor housing by using a caulking fixing technique as disclosed in Patent Document 1 described above. This technique is difficult to apply to a motor with a relatively high output specification such as a motor with a reduction gear, and is also a disadvantageous technique in terms of cost.

  In order to solve such problems, the present invention reliably fixes the motor housing, the end bell, and the gear box of the speed reducer without making a special design change to the fixing method itself of the end bell to the motor housing. The purpose is that.

  In addition, the present invention prevents the change of the bearing position provided on the end bell without lifting the end bell from the motor housing and maintains the alignment constant, thereby preventing abnormal sliding and abnormal noise between the brush and the commutator. The purpose is to suppress the occurrence.

  A motor with a speed reducer in which a motor portion and a speed reducer portion according to the present invention are integrally assembled, and a method for manufacturing the motor include a resin end bell fitted to a motor housing opening side of a bottomed hollow cylindrical motor housing, The rotating shaft that passes through the end bell that houses the bearing is extended to extend inside the reduction gear. The speed reducer portion has a resin gear box that houses a worm fixed to the rotating shaft and a helical gear meshing with the worm. The step portion of the resin gear box is faced in the shaft axial direction on one surface of the end bell, and a plurality of integrally formed protrusions are provided on one surface of the facing end bell or gear box, and the protrusion is The gear box is fixed to the motor housing in a state where it is pressed against the other surface of the facing end bell or gear box.

  The protrusion pressed against the other surface of the facing end bell or gear box has its tip side crushed or bite into the other surface. The motor part and the speed reducer part are fixed by fixing a flange part formed by pushing the opening of the motor housing outward in the radial direction to one end of the gear box. The end bell is provided with an integrally formed flange portion at the periphery thereof, and a step portion of the gear box is opposed to the shaft axial direction on one surface of the flange portion. The shape of the protrusion may be a two-stage structure with a reduced tip side diameter. The height of the protrusion is larger than the difference between the maximum dimension considering the manufacturing tolerance from the flange part of the housing to the step part of the gear box and the minimum dimension considering the manufacturing tolerance of the flange part thickness of the end bell. . Further, a waterproof packing for performing a sealing function between the motor housing and the end bell fitted into the housing opening can be inserted between the stepped portion of the gear box and the motor housing.

  According to the present invention, since the motor housing, the end bell, and the gear box of the speed reducer section are securely fixed, the change in the bearing position provided in the end bell can be prevented without lifting the end bell from the motor housing. Further, by maintaining the alignment constant, it is possible to suppress abnormal sliding and abnormal noise between the brush and the commutator.

It is a longitudinal cross-sectional view of the motor with a reduction gear comprised based on this invention. It is a figure which takes out and shows the motor part shown in FIG. (A) is a front view of the reduction gear gear box as viewed from the motor mounting side, (B) is a perspective view thereof, and (C) is a diagram showing an example of a protrusion shape provided in a stepped portion. is there. It is a front view of the end bell seen from the housing side. It is a conceptual diagram for demonstrating the fixing structure between a motor housing, an end bell, and a gear box. It is a figure explaining the height of protrusion. It is a figure explaining the effect | action of a waterproof packing, (A) and (B) have each shown different waterproof packing structure. It is a figure which shows the fixing structure of the motor housing and end bell which are disclosed by patent document 1, (A) is a side view of a motor housing, (B) is a front view of the end bell fixed to the opening part, (C) is side sectional drawing of the motor after an assembly.

  Hereinafter, the present invention will be described based on examples. FIG. 1 is a longitudinal sectional view of a motor with a reduction gear constructed according to the present invention. This motor with a speed reducer is a motor part and a speed reducer part assembled together. This assembly is performed by fixing the flange portion formed by pushing the opening of the metal motor housing outward in the radial direction to the resin gear box with mounting bolts (or mounting screws). The rotating shaft extends to the outside of the motor unit and extends to the inside of the speed reducer unit. The speed reducer portion attached to the motor portion via attachment bolts accommodates a worm fixed to a rotating shaft and a worm wheel constituted by a helical gear meshing with the worm wheel in a resin gear box. The tip of the rotating shaft is supported by a third bearing housed in the gear box. Furthermore, although the fourth bearing supporting the rotating shaft is illustrated as being provided in the gear box, the fourth bearing is not necessarily required. When the motor of the motor unit is driven, the rotating shaft rotates, and this rotation decelerates and rotates the worm wheel through the worm, which in turn rotates the output shaft through the buffer member and the like. Then, by rotation of the output shaft, for example, the window glass of the automobile can be opened and closed via a driving means (not shown). The present invention is characterized by the combined configuration of the motor portion and the speed reducer portion. The illustrated gear box has a plurality of protrusions on the contact surface with the end bell (details will be described later). The configurations of the motor unit and the speed reducer unit other than the coupling component can be the same as those conventionally known.

  FIG. 2 is a view showing the motor unit shown in FIG. In the motor unit, a magnet is attached to an inner peripheral surface of a housing formed of a metal material in a bottomed hollow cylindrical shape. The opening of the housing is closed by a case lid (resin end bell) fitted thereto. Further, a flange portion is formed on the opening side of the housing by expanding outward in the radial direction, and the flange portion is fixed to the resin gear box (see FIG. 1). On the rotating shaft, a rotor magnetic pole constituted by a laminated core wound with a winding and a commutator are provided to constitute a motor rotor. A pair of input terminals connected to the pair of brushes that come into contact with the commutator pass through the end bell and project outside the motor for electrical connection. One end of the rotating shaft is supported by a first bearing provided at the center of the bottom of the bottomed hollow cylindrical housing. The other end of the rotating shaft is supported by a second bearing housed in the central portion of the end bell, and further extended from the outside to the outside of the motor unit, as described with reference to FIG. It extends to. As described above, the resin end bell is fitted into the opening of the metal motor housing and has a function of supporting the pair of brushes, the pair of input terminals, the second bearing, and the like.

  FIG. 3A is a front view of the reduction gear gear box as viewed from the motor mounting side, FIG. 3B is a perspective view thereof, and FIG. 3C shows an example of a protrusion shape provided in the stepped portion. FIG. In the center hole shown in FIG. 3 (A) or (B), a rotating shaft extending from the motor portion extends. As will be described later, the step portion of the resin gear box abuts on the flange portion of the end bell through protrusions (four examples) integrally formed thereon. The screw holes (illustrated as three) are for abutting against the flange portion (see FIG. 1) of the motor housing and fastening with bolts (or screws). The protrusion shape has, for example, a two-stage structure as shown in FIG. An example of the size is a base diameter: 2 mm, a tip diameter: 1 mm, and a height: 1 mm. The protrusion having a two-stage structure with a reduced tip side diameter allows the tip to be crushed or the tip to bite into the flange portion of the end bell without breaking. Moreover, although the example protrusion is illustrated as being provided with four pieces, the end bell surface can be uniformly pressed if there are three or more pieces.

  FIG. 4 is a front view of the end bell as seen from the housing side. A bearing holder that houses a bearing is provided in the central portion of the end bell that is integrally formed of resin, and the rotating shaft extends from the center to the outside of the motor. A flange portion is provided by integral molding around the end bell (for example, on the upper and lower sides in the figure of the end bell as illustrated). The protrusion provided in the step portion of the gear box described with reference to FIG. 3 is brought into contact with and pressed on the surface of the flange portion (the back side position of the “protrusion abutting position” as viewed from the inside of the motor). The tip of the projection is crushed or bites into the end bell. Whether the tip of the protrusion is crushed or bites into the end bell depends on the resin used for the end bell and the gear box (its hardness). For example, when a glass fiber-containing polyamide resin is used for the end bell material and a polybutylene terephthalate compounded with glass fiber is used for the gear box material, the hardness of the gear box and the protrusion integrated therewith is harder than that of the end bell. Will bite into the end bell.

  FIG. 5 is a conceptual diagram for explaining a fixing structure among the motor housing, the end bell, and the gear box. The end bell is fitted and fixed in the opening of the motor housing, and the flange portion of the motor housing and the fixing surface of the gear box are fixed by, for example, bolting. At this time, the step portion of the resin gearbox is made to face the shaft axial direction on one surface of the end bell (flange portion). As described above, the step portion of the gear box forms a step with a predetermined interval (dimension A shown in FIG. 6) with respect to the fixed surface with the motor housing. In the illustrated example, a protrusion is provided on the step portion side of the gear box, and when the gear box is fixed to the motor housing, the end bell (flange portion) is pressed to press the end of the protrusion. . The tip of the pressed projection is crushed or bites into the end bell flange. Although the projection is described as being provided on the gear box side and abutting on the end bell side, the projection of the present invention can be provided on the end bell side and abutting on the gear box side. Since the surface of the end bell or the stepped portion of the gear box is made of resin, it is difficult to manufacture a complete flat surface. It is practically difficult to hold down evenly. On the other hand, according to the present invention, it is easy to hold a plurality of points evenly at a plurality of points or at an arbitrary height by using protrusions instead of pressing with a surface or a line.

FIG. 6 is a diagram illustrating the height of the protrusion. As shown in the figure, the height of the protrusion is C, the dimension from the flange portion of the housing to the step portion of the gear box is A ± X, and the thickness of the end bell (flange portion) with which the protrusion abuts is B ± Y. . Here, X and Y represent manufacturing tolerances (for example, about 0.1 to 0.2 mm with respect to the projection height C = 1 mm). At this time, if there is a gap between the tip of the projection and the contact surface of the end bell, the end bell cannot be pressed. Therefore, the protrusion height C is larger than the difference between the maximum dimension (A + X) up to the stepped portion of the gear box considering the manufacturing tolerance and the minimum dimension (BY) of the end bell thickness considering the manufacturing tolerance. (For example, bite about 0.15 mm). That is,
C> (A + X)-(BY) (1)
If the projection can sufficiently contact the housing and the end bell in a state where the end bell is pressed, it is not always necessary to crush the tip of the projection or to bite into the end bell flange portion. That is,
C ≧ (A + X) − (BY) (2)
Also holds.

FIG. 7 is a diagram for explaining the operation of the waterproof packing, and (A) and (B) show different waterproof packing structures. The waterproof packing serves to perform a sealing function between the motor housing and the end bell fitted into the housing opening. The waterproof packing shown in (A) has a ring-shaped structure that surrounds the outer peripheral side of the end bell so as to enter the gap on the radially outer side of the end bell (flange portion). In addition to the ring-shaped structure shown in (A), the waterproof packing shown in (B) has a structure that further fills the gap on the inner peripheral side. However, at the protrusion position, a hole (protrusion relief) is provided in the waterproof packing. As described with reference to FIG. 5, by providing the protrusion on the gear box, the end bell fitted into the opening of the motor housing is pressed down so that the housing and the end bell are brought into close contact with each other. Furthermore, a waterproof function can be achieved by inserting a waterproof packing between the step portion of the gear box and the flange portion of the motor housing.

Claims (9)

In a motor with a speed reducer that integrally assembles a motor part and a speed reducer part,
The motor part is fitted with a case lid on the opening side of the bottomed hollow cylindrical motor housing, and extends to the inside of the speed reducer part by extending a rotating shaft penetrating the case lid containing the bearing therein. ,
The speed reducer portion has a gear box that houses a worm fixed to the rotating shaft and a gear meshing with the worm,
A step portion of the gear box is made to face the shaft axial direction on one surface of the case lid, and a plurality of protrusions are provided on one surface of the facing case lid or gear box, and the protrusion is A motor with a speed reducer comprising: the gear box fixed to the motor housing in a state of being pressed against the other surface of the facing case lid or gear box. The motor with a reduction gear according to claim 1, wherein the protrusion pressed against the other surface of the facing case lid or the gear box is crushed at a leading end side or bites into the other surface. The motor with a reduction gear according to claim 2, wherein the gear box is fixed to the motor housing by fixing a flange portion formed radially outside the opening of the motor housing to one end of the gear box. The motor with a reducer according to claim 3, wherein the case lid is provided with an integrally formed flange portion in the periphery thereof, and a step portion of the gear box is opposed to the shaft axial direction on one surface of the flange portion. The motor with a reduction gear according to claim 4, wherein the shape of the protrusion is a tip side diameter smaller than a root side diameter. The height of the protrusion is larger than the difference between the maximum dimension considering the manufacturing tolerance from the flange part of the housing to the stepped part of the gear box and the minimum dimension considering the manufacturing tolerance of the flange part thickness of the case lid. The motor with a reduction gear according to claim 2, which is enlarged. The waterproof packing for fulfilling the sealing function between the motor housing and the case lid fitted in the housing opening is inserted between the stepped portion of the gear box and the motor housing. The motor with a reduction gear described. In the manufacturing method of the motor with a reduction gear in which the motor portion and the reduction gear portion are assembled together,
The motor part is fitted with a case lid on the opening side of the bottomed hollow cylindrical motor housing, and extends to the inside of the speed reducer part by extending a rotating shaft penetrating the case lid containing the bearing therein. ,
The speed reducer portion includes a gear box that houses a worm fixed to the rotating shaft and a gear meshing with the worm.
The stepped portion of the gear box is made to face the shaft axial direction on one surface of the case lid, and a plurality of protrusions are provided on one surface of the facing case lid or gear box,
A method of manufacturing a motor with a reduction gear, comprising: fixing the gear box to the motor housing in a state where the projection is pressed against the other surface of the facing case lid or the gear box. The manufacturing method of the motor with a reduction gear according to claim 8, wherein the protrusion pressed against the other surface of the facing case lid or the gear box is crushed at the tip side or bites into the other surface.

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