Motor apparatus having rotational position detector

A motor apparatus is provided with a yoke housing, a gear housing and a brush holder. A receiving portion of the gear housing receives the worm wheel, etc. therein. The brush holder is interposed between the yoke housing and the gear housing. The worm wheel is provided with a switching plate on one side face thereof, which is in slide contact with contact members. The gear housing is provided with a housing body and a cover. In the housing body is formed a communication hole to communicate an internal spaces of the receiving portion and a yoke housing. The contact members are disposed on the brush holder and on the bottom portion side of the receiving portion with respect to the worm wheel so as to extend through the communication hole into the gear housing.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of Japanese Patent Applications No. 2004-244157 filed on Aug. 24, 2004 and No. 2004-244159 filed on Aug. 24, 2004, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a motor apparatus having a rotational position detector, especially the motor apparatus suitable for wiper system of a vehicle.

BACKGROUND OF THE INVENTION

Conventionally, a motor apparatus is in use that has a motor unit provided with an armature and a gear unit provided with a speed reduction mechanism. In the speed reduction mechanism, a face of a wheel gear is provided with a switching plate having a specific conductor pattern thereon, and a gear housing of the gear unit is provided with a fixed terminal (refer to JP-06-44371-U, for example). In this kind of motor apparatus, a contact between the switching plate and the fixed terminal, which are in accordance with a rotational position of the wheel gear, serves as a switching detector, so that the motor apparatus is suitable for a wiper motor, for example. That is, this kind of motor apparatus is provided with a so-called automatic return-and-stop mechanism. When a wiper switch is turned off to stop an operation of a wiper system, the motor apparatus does not stop at once, but stops after moving the wiper arm to a specific off position on a window of a vehicle.

In the above-described motor apparatus according to JP-06-44371-U, the gear housing includes a housing body, which is provided with a receiving depressed portion to receive the wheel gear, etc., and a cover, which is fixed on the receiving depressed portion to cover that. On a bottom portion of the receiving depressed portion is formed a receiving portion. An output shaft of the motor apparatus is inserted into and supported by the receiving portion. The wheel gear, a motion conversion mechanism to convert a rotational rotation of the wheel gear into a reciprocating swing motion of the output shaft, the fixed terminal and the cover are assembled in turn in an axial direction of the receiving portion, namely in a depressing direction of the receiving portion.

However, the receiving portion disposes both a mechanically moving structure such as the motion conversion mechanism and an electrical structure such as the fixed terminal and the switching plate of the wheel gear in a single space therein. Thus, it is necessary to dispose the mechanically moving structure and the electrical structure so as to avoid an interference between them, thereby an electrical wiring structure is disposed outside the gear housing. Accordingly, a connector unit (wiring), which is fixed outside the gear housing, connects a connection terminal of the fixed terminal and a connection terminal connected to a brush to energize the armature, to make a wiring structure long and complicated, to increase the number pf parts and working processes, and to decrease a reliability of a waterproofness of the wiring structure.

SUMMARY OF THE INVENTION

The present invention is achieved to solve the above-described issues, and has an object to provide a motor apparatus, of which a wiring structure can be short and simple, a waterproofness of the wiring structure can be secured easily and reliably and further an assembling workability is improved.

The motor apparatus has a motor unit, a connector portion and a speed reduction unit. The motor unit is provided with an internal terminal and energized via the internal terminal. The connector portion has an external terminal. The speed reduction unit is provided with a worm shaft, a worm wheel, a switching plate and a gear housing. The worm shaft is rotationally driven by the motor unit. The worm wheel reduces and outputs a rotation of the worm shaft. The switching plate integrally rotates with the worm wheel and has a predetermined electrical conductor pattern to come in contact with the internal terminal and the external terminal in accordance with a rotational position of the worm wheel to connect and disconnect between the external terminal and the internal terminal. The gear housing is fixed to the motor unit and encloses the worm shaft, the worm wheel and the switching plate therein. The gear housing is provided with a communication hole, which is covered by an outer face of the motor unit and lets the internal terminal and the external terminal therethrough toward the switching plate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following is described a motor apparatus according to an embodiment of the present invention. A motor apparatus1is for actuating a wiper system (specifically a rear wiper system). As shown inFIG. 1, the motor apparatus1is provided with a motor unit2and gear unit (speed reduction unit)3.

The motor unit2is provided with a yoke housing4formed in an approximately cylindrical shape with a bottom. The yoke housing4has a circumferential face including a pair of arc portions4aand a pair of flat portions4b. The flat portions4aare disposed radially outward with respect to the flat portions4b. As shown inFIG. 2, the motor unit2is further provided with a pair of magnets5and an armature6. The yoke housing4encloses the magnets5and the armature6therein. The yoke housing4holds the magnets5on an inner face of the arc portions4b, and rotatably supports the armature6. The arc portions4aare opposed to each other in a width direction Dw of the motor unit2, which is perpendicular to a rotational axis of the armature6. The flat portions are in parallel with and opposed to each other in a thickness direction Dt of the motor unit2, which is perpendicular to the width direction Dw and to the rotational axis of the armature6. The flat portions4bconnect the arc portions4a. At a brim of an opening end of the yoke housing4is formed a flange portion4cto extend radially outward.

At the opening end of the yoke housing4is disposed a brush holder7. The brush holder7, as shown inFIGS. 2 to 5, is provided with a brush holder resin body7a, which is made of an electrical insulating resinous material. The brush holder resin body7ais an integrated body of a holder body portion7b, a flange portion7c(refer toFIG. 4), an extension portion7d, a connector portion7eand a contact base portion7f.

The holder body portion7bis installed approximately inside an opening side portion of the yoke housing4. As shown inFIG. 2, the holder body portion7bis provided with a center hole to hold a bearing8therein. The bearing8rotatably supports a leading end side portion of a rotation shaft9of the armature6. Further, the holder body portion7bholds brushes10a,10bof the motor unit2, which is for energizing the armature6. The brushes10a,10bare disposed inside the yoke housing4and in pressure contact with a rectifier11, which is fixed on the rotation shaft9. The flange portion7cextends radially outward from the holder body portion7bin a flange-like manner. The extension portion7dextends in the width direction Dw of the motor unit2from a part of the flange portion7cto a position radially outer than the arc portions4aof the yoke housing4with respect to the rotation shaft9.

The connector portion7eis formed at a leading end of the extension portion7d. The connector portion7eis formed to snap an external connector (not shown) thereto in an axial direction of the armature6(downward inFIG. 2). Specifically, the connector portion7ehas an approximately rectangular tube shape that opens at one end thereof in the axial direction of the armature6(upper side end inFIG. 2) to have a C-shaped cross-section. The connector portion7eis disposed at a side of one of the arc portions4a(one arc portion4a) of the yoke housing4. An outline of the connector portion7eis disposed within a range T (refer toFIG. 7) between the pair of the flat portions4bin the thickness direction Dt of the motor unit2.

As shown inFIGS. 2 and 4, the contact base portion7fextends from a part of the brush holder resin body7a, which is between the holder body portion7band the connector portion7eand corresponds to the extension portion7dand/or the flange portion7c, away from the yoke housing4(downward in the figures). As shown inFIG. 5, the contact base portion7fis disposed in a butt joining region B, in which the yoke housing4and the gear housing41are butt-joined to each other to interpose the brush holder resin body7atherebetween, so as to be closer to one of the flat portions4b(one flat portion4b) than to the other of the flat portions4b(the other flat portion4b) in the thickness direction Dt of the motor unit2(at a lower side inFIG. 5). The contact base portion7fhas a plate-like shape, which is thin in the thickness direction Dt of the motor unit2(refer toFIG. 1).

As shown inFIG. 5, the brush holder7is further provided with five terminals21–25, which are made of electrical conducting metal plates. Each of the terminals21–25is embedded in the brush holder resin body7ato expose a part thereof.

The terminal21is for a first power source (high voltage power source). As shown inFIGS. 3 and 5, one end portion of the terminal21is exposed outside the connector portion7e. The terminal21extends from the one end portion thereof to the holder body portion7b. The other end portion of the terminal21is connected to a first terminal of a capacitor26, which is mounted on the holder body portion7b. The other end is also connected via a choke coil27, which is mounted on the holder body portion7b, to the brush10a.

The terminal22is for a second power source (low voltage power source). One end portion of the terminal22is exposed outside the connector portion7e. The terminal22extends from the one end portion thereof to the holder body portion7b. The other end portion of the terminal22is connected to a first terminal of a circuit breaker28, which is mounted on the holder body portion7b. The terminal22is provided with a contact terminal22a, which is branched between the one and the other end portions thereof. The contact terminal22aextends to the contact base portion7f. As shown inFIG. 6, the contact terminal22ais provided with a rise portion22bat a (most) leading end portion thereof in the contact base portion7f. The contact terminal22ais disposed so that a plate thickness direction thereof is in parallel with the thickness direction Dt of the motor unit2(refer toFIG. 1), or in other words, so that a plate flatness direction thereof is in parallel with the width direction Dw of the motor unit2. The rise portion22bis bent to protrude over one face (an upper surface inFIGS. 5 and 6) of the contact base portion7f, which is closer to the other flat portion4bthan to the one flat portion4b.FIG. 6depicts the rise portion22b, which is cottered as described below.

The terminal23is for a first fixed contact. One end portion of the terminal23is exposed outside the connector portion7e. Another end portion of the terminal23forms a contact terminal23a, which is disposed in parallel with the contact terminal22a. As shown inFIG. 4, the contact terminal23ais provided with a rise portion23bat a (most) leading end portion of the contact terminal23a. The rise portion23bhas substantially the same shape as the rise portion22b.

The terminal24is for the second fixed contact. One end portion of the terminal24is exposed outside the connector portion7e. Another end portion of the terminal24forms a contact terminal24a, which is disposed in parallel with the contact terminals22a,23a. As shown inFIG. 4, the contact terminal23ais provided with a rise portion23bat a (most) leading end portion of the contact terminal23a. The rise portion23bhas substantially the same shape as the rise portions22b,23b. As shown inFIGS. 2 and 4, the leading end portions of the contact terminals22a–24a(the rise portions22b–24b) are aligned to be inclined to the rotation axis of the armature6.

The terminal25is for a middle connection and disposed on the holder body portion7b. As shown inFIGS. 3 and 5, one end portion of the terminal25is connected to a second terminal of the capacitor26. The other end portion of the connector25is connected to a second terminal of the circuit breaker28. A middle portion of the terminal25is connected via a choke coil29, which is mounted on the holder body portion7b, to the brush10b.

As shown inFIGS. 2,4and5, the brush holder7is further provided with contact members31–33. The contact members31–33are respectively electrically connected to the most leading end portions of the contact terminals22a–24a, namely the rise portions22b–24b. Specifically, each of the contact members31–33is made of an electrical conducting metal plate having specific elasticity to serve as a leaf spring. As shown inFIGS. 4 and 6, each of the contact members31–33is provided with a base end portion31b–33b, an inclined portion31c–33cand a leading end portion31d–33d. Each of the base end portion31b–33bis provided with a through hole31a–33a. The leading end portions31d–33dare formed at the leading end of the inclined portions31c–33c. The inclined portion31c–33cextend from the base end portion31b–33bto the leading end portions31d–33dto be elastically bent and inclined to the one face of the contact base portion7f. As shown inFIG. 6, the contact members31–33are respectively fixed on the rise portions22b–24bby inserting the rise portions22b–24bthrough the through holes31a–33aand cottering them. The contact base portion7fis provided with assembly bores7gon the other face thereof so that the assembly bores7galign with the rise portions22b–24b. In cottering the contact members31–33onto the rise portions22b–24b, an assembly jig is inserted into the assembly bores7gto support the rise portions22b–24bat bottom sides opposite from cottering sides thereof. The contact members31–33are aligned side by side to extend in parallel with each other. In the present embodiment, the contact terminals22a–24aand the contact members31–33form three fixed contacts, which are aligned side by side on a plane in parallel with the flat portions4b.

As shown inFIGS. 3 to 5, the brush holder7is provided with a seal34at the brush holder resinous body7a. The seal34is made of elastomer and disposed to approximately surround the flange portion7c, the extension portion7dand so on.

As shown inFIGS. 1 and 2, the gear portion3is provided with a gear housing41, a worm shaft42, a worm wheel43, a sector gear (sub gear)44, a distance keeping plate45and an output shaft46. In the present embodiment, the worm shaft42and the worm wheel43form a speed reduction mechanism and a worm speed reduction mechanism to reduce a rotation of the armature6and output a reduced rotation.

The gear housing41is provided with a housing body51and a cover52. In the housing body51is formed a receiving depressed portion (receiving portion)51a, which opens to the other flat portion4bside in the thickness direction Dt of the motor unit2, namely frontward inFIG. 2. The cover52is fixed on and covering the receiving depressed portion51a(a part of which is shown inFIG. 2).

The housing body51is a die-cast member made of aluminum alloy, which is an electric conductor material. The yoke housing4side end portion of the housing body51, which is a part of an outer wall of the receiving depressed portion51a, forms a fixing portion51b. The fixing portion51bhas a shape corresponding to the opening side portion (flange portion4c) of the yoke housing4. The housing body51is screw-fastened at the fixing portion51bto the flange portion4cof the yoke housing4so that the fixing portion51band the flange portion4cof the yoke housing4interpose the flange portion7cof the brush holder7and the seal34therebetween. That is, the yoke housing4and the gear housing41are connected so that the brush holder7is abutted therebetween. As shown inFIG. 7, the fixing portion51bof the housing body51is further provided with a center hole51cand a communication hole51d, which respectively communicate an interior space of the receiving depressed portion51aand an interior space of the yoke housing4. In an assembled body of the yoke housing4, the brush holder7and the gear housing41, the leading end side portion of the rotation shaft9extends through the center hole51cinto the receiving depressed portion51aof the gear housing41, and the contact base portion7fextends through the communication hole51dinto the receiving depressed portion51aof the gear housing41. The motor unit2and the gear housing41block the communication hole51dfrom an outer space.

As described above, the receiving depressed portion51aopens to the other flat portion4bside in the thickness direction Dt of the motor unit2, namely frontward inFIG. 2. Thus, the contact base portion7fand the fixed contacts (the contact terminals22a–24aand the contact members31–33), which are closer to the one flat portion4bthan to the other flat portion4b(rearward inFIG. 2), is disposed in a bottom portion side in the receiving depressed portion51awith respect to the worm wheel43. Further, as shown inFIG. 6, at a position on the bottom portion of the receiving depressed portion51aof the housing body51, which corresponds to a position of the contact base portion7f, is provided with a contact face S to come in contact with the contact base portion7f. The contact face S is formed on an inner face of the housing body51beyond the leading end portions of the contact terminals22a–24awith respect to the assembly bores7gof the contact base portion7f. Thus, a leading end portion of the contact base portion7fcomes in contact with the contact face S. Furthermore, at a position on the bottom portion of the receiving depressed portion51aof the housing body51, which corresponds to the assembly bores7g, is provided with a depression with respect to the contact face S. In the depression is formed a cavity K as an insulation portion to insulate the contact terminals22a–24afrom the housing body51.

The receiving depressed portion51aincludes a worm receiving portion51e, a wheel receiving portion51f, an output shaft receiving portion51gand so on, which communicates with one another therein.

The worm receiving portion51eis formed to extend on an extension line of the rotation shaft9, and rotatably supports the worm shaft42therein. A joint53connects the worm shaft42and the rotation shaft9so as to integrally rotate them.

As shown inFIG. 2, the wheel receiving portion51fis disposed at the same side as the connector portion7ewith respect to the worm receiving portion51e, and rotatably supports the worm wheel43therein. A part of the worm wheel43is engaged with the worm shaft42. The worm wheel43is disposed so that a rotational axis thereof is in parallel to the thickness direction Dt of the motor unit2. As shown inFIG. 8, on one side face of the worm wheel43, which is opposed to a bottom face of the receiving depressed portion51a, is provided with a switching plate54. The switching plate54has a specific conductor pattern, which is conventionally known, thereon. Specifically, the switching plate54is integrally formed with the worm wheel43. The leading end portions31d–33dof the contact members31–33come in pressure and slide contact with the switching plate54. Each of the leading end portions31d–33dof the contact members31–33comes in and out of contact with the specific conductor pattern on the switching plate54, in accordance with a rotational position of the worm wheel43.

The output shaft receiving portion51gis formed on an opposite side from the connector portion7eand the wheel receiving portion51fwith respect to the worm receiving portion51e. As shown inFIG. 1, the output shaft receiving portion51gis provided with an output shaft supporting portion51hat a center thereof to extending outward in a cylinder-like shape in the thickness direction Dt of the motor unit2. The output shaft receiving portion51grotatably supports the output shaft46. A base end portion of the output shaft46is disposed in the output shaft receiving portion51g, and a leading end portion of the output shaft46protrudes out of the output shaft receiving portion51g. The leading end portion of the output shaft46is associated with and actuates a wiper (rear wiper) W of a vehicle, which is schematically shown inFIG. 1.

The worm wheel43and the output shaft46are interlocked with each other by the sector gear44and the distance keeping plate45. The sector gear44and the distance keeping plate45are respectively formed from metal plates. Specifically, a base end of the sector gear44is rotatably linked with a position of the worm wheel43, which is radially displaced from the rotational axis thereof. At a leading end portion of the sector gear44ais formed a gear portion44, and at a base end portion of the output shaft46is formed a gear portion46ato be engaged with the gear portion44aof the sector gear44. As shown inFIG. 7, the sector gear44is disposed on the opening side (left side inFIG. 7, frontward side inFIG. 2) of the receiving depressed portion51awith respect to the worm wheel43. One end portion of the distance keeping plate45is rotatably linked with a radial center of the gear portion44aof the sector gear44. The other end portion of the distance keeping plate45is rotatably linked with a base end portion of the output shaft46. That is, the distance keeping plate45keeps a distance between the radial center of the gear portion44aand a rotational axis of the output shaft46. As shown inFIG. 7, the distance keeping plate45is disposed at the opening side (left side inFIG. 7, frontward side inFIG. 2) of the receiving depressed portion51awith respect to the sector gear44. Thus, the sector gear44(and the distance keeping plate45) converts the rotation of the worm wheel43into a reciprocating rotational motion of the output shaft46to swing the wiper W reciprocatingly to wipe a surface of a rear window of a vehicle.

Next, an electric configuration of the motor apparatus1and an external control unit for controlling the wiper system will be described with reference toFIG. 9. The motor apparatus1and the external control unit are connected to each other by snapping the external connector of the external control unit to the connector portion7e.

The terminals21,23,24exposed in the connector portion7eare respectively connected to a selector switch61provided in a driver's seat of the vehicle. The terminal22is connected to the ground. The terminal24exposed in the connector portion7eis connected to the power source E, namely a battery of the vehicle. In the present embodiment, the selector switch61, the ground and the power source E forms the external control unit.

The selector switch61has an “off” position P1to turn off the motor apparatus1and an “on” position P2to turn on the motor apparatus1. The selector switch61connects the terminal21to the terminal23when turned in the off position P1connects the terminal21to the power source E when turned in the on position P2.

In the motor apparatus1having an electrical wiring as described above, when the selector switch61is turned in the on position P2, the brush10aof the motor unit2is connected to the power source E to operate the motor apparatus1. That is, the output shaft46comes in a reciprocating rotational motion to actuate the wiper W.

When the selector switch61is switched from the on position P2into the off position P1, a direct connection between the brush10aand the power source E is interrupted, and the brush10ais connected via the terminal23to the contact member32. Here, if the switching plate54, which integrally rotates with the worm wheel43, is in a specific angular position to connect the contact member31and the contact member32, the terminal23, which is connected to the brush10a, is connected via the contact members31,32to the ground, so that the motor apparatus1stops.

If the switching plate54is not in the specific angular position but in a position to connect the contact member32and the contact member33, the terminal23, which is connected to the brush10a, is connected via the contact members32,33to the power source E. Thus, the motor apparatus1continues to operate. Then, when the switching plate54, integrally rotating with the worm wheel43, comes up to the specific angular position, the terminal23, which is connected to the brush10a, is connected via the contact members31,32to the ground, so that the motor apparatus1stops. That is, the selector switch61is switched from the on position P2into the off position P1, a rotational position of the switching plate54, which is detected by a contact between the contact members31–33(contact portions31d–33d) and the switching plate54, automatically stops the switching plate54and the worm wheel43at the specific angular position.

When the switching plate54and the worm wheel43are in the specific angular position as in a state shown inFIG. 9, the wiper W is configured to be in a specific off position such as a position along a lower end of the rear window. Thus, by switching the selector switch61from the on position P2into the off position P1, the wiper W automatically stops at the specific off position.

Next, advantageous actions and effects of the motor apparatus1according to the above-described embodiment will be described in the following.

(1) The fixed contacts (the contact terminals22a–24aand the contact members31–33) are provided in the brush holder7, so that electric devices are gathered in the brush holder7together with the brushes10a,10b. Thus, even in such a case that the contact terminal22aand the contact member31are connected to the brush10b, a wiring structure to connect them can be simplified into only the terminals22,25provided at the brush holder7. Further, even when the contact terminals22a–24aand the contact members31–33, together with the brushes10a,10b, are connected to the external control unit (the selector switch61, ground and the power source E), a wiring structure to connect them can be simplified into only the terminals21–25provided in the brush holder7.

Moreover, the fixed contacts (contact terminals22a–24aand the contact members31–33) are provided to extend from the brush holder7through the communication hole51d, which is formed on the yoke housing4side end portion of the housing body51of the gear housing41, into the receiving depressed portion51aof the gear housing41. Thus, it is possible to provide a wiring to connect the contact terminal22aand the contact member31with the brush10b, namely the terminals22,25, with shortness and waterproofness easily and securely than in a conventional motor apparatus having the wiring outside a gear housing.

Further, the fixed contacts (contact terminals22a–24aand the contact members31–33) are disposed at the bottom portion side of the receiving depressed portion51awith respect to the worm wheel43; thereby, the fixed contacts, which are disposed at the bottom portion side portion in the assembled body of the yoke housing4, the housing body51and the brush holder7, do not hamper the worm wheel43and so on from being installed in the receiving depressed portion51a, regardless of an arrangement of the fixed contacts protruding into the receiving depressed portion51a. That is, after assembling the yoke housing4, the housing body51and the brush holder7to protrude the fixed contacts into the receiving depressed portion51a, it is possible to install the worm wheel43and so on easily in the receiving depressed portion51a. Here, the fixed contacts have elasticity in a direction perpendicular to the surface of the switching plate54, which is integrally formed on the worm wheel43, to serve as leaf springs to come in pressure contact with the switching plate54. Then, after disposing the fixed contacts on the bottom portion of the receiving depressed portion51a, the worm wheel43can be installed in the direction of the elasticity; thereby the fixed contacts can easily and securely come in pressure contact with the switching plate54.

(2) The brush holder7is provided with the connector portion7ethat is disposed outside the yoke housing4and the gear housing41, to connect the external connector of the external control unit (the selector switch61, the ground and the power source E) thereto; thereby the electric devices are further gathered in the brush holder7. Thus, the wiring structure of the terminals of the brushes10a,10b, the fixed contacts and the connector portion7eis simplified into only the terminals21to25as compared with a motor apparatus in which a connector portion and a brush holder are separately disposed. Especially, by forming the brush holder7to embed the terminals21–25therein by insert molding to arrange the terminals21–25in the molded brush holder resinous body7a, an electric insulation performance of the terminals21to25is more reliably secured.

(3) The connector portion7eis disposed at the same side as the worm wheel43with respect to the worm shaft42. Thus, a structure to shorten a distance between the connector portion7eand the fixed contacts (the contact terminals22a–24aand the contact members31–33) goes with a structure to dispose the fixed contacts, which are in slide contact with the switching plate54formed on the worm wheel43, at the same side as the worm wheel43with respect to the worm shaft42so as not to interfere with worm shaft42. Accordingly, it is possible to dispose the fixed contacts not to interfere with the worm shaft42and to shorten a wiring (terminals22–24) to connect the fixed contacts and the connector portion7e. Further, for instance, the fixed contact can be disposed between the holder body portion7band the connector portion7e, so that the brush holder7can be formed in a relatively small size.

(4) The brush holder7has the contact base portion7fintegrally formed with the holder body portion7bto extend through the communication hole51dinto the receiving depressed portion51atogether with the fixed contacts (contact terminals22a–24aand the contact members31–33). That is, the fixed contacts are supported by the contact base portion7f, which is integrally formed with the holder body portion7b, to extend into the receiving depressed portion51a. Thus, the fixed contacts, provided to come in slide contact with the switching plate54formed on the worm wheel43, can be supported in the proximity to the worm wheel43in the gear housing41; thereby the fixed contacts can easily and reliably be in pressure contact with the switching plate54. Further, the contact base portion7fintegrally formed with the holder body portion4bdecreases the number of parts of the motor apparatus1.

(5) The contact base portion7fand the holder body portion7bare made of resinous material, and the other face (a lower surface inFIGS. 5 and 6) of the contact base portion7f, which is opposite from the fixed contacts (the contact terminals22a–24aand the contact members31–33) in contact with the switching plate54, is directly supported by the housing body51. Thus, the housing body51receives a reaction force of a pressure contact force of the fixed contacts, thereby the contact base portion7fis prevented from deforming and the fixed contacts can more easily and reliably be in pressure contact with the switching plate54formed on the worm wheel43.

Further, the contact base portion7f, which supports the fixed contacts (the contact terminals22a–24aand the contact members31–33), extends from the brush holder resinous body7a(the extension portion7dand/or the flange portion7cbetween the holder body portion7band the connector portion7e) in the butt joining region B, in which the yoke housing4and the gear housing41are butt-joined to each other to interpose the brush holder resin body7atherebetween. Thus, yoke housing4and the gear housing41confine the brush holder resin body7atherebetween to decrease a deformation of the brush holder resin body7a; thereby a rotational position detection accuracy and a switching accuracy by the fixed contacts can be secured.

Furthermore, in the butt joining region B, the yoke housing4, the gear housing41and the brush holder resin body7aform a watertight space therein. Thus, the watertight space renders the fixed contacts (the contact terminals22a–24aand the contact members31–33) waterproofness together with the electric devices mounted on the brush holder resin body7a.

(6) The fixed contacts comprise the contact terminals22a–24a, which are parts of the terminals22–24disposed in the brush holder7, and the contact members31–33, which are anchored on the leading ends (the rising portions22b–24b) of the contact terminals22a–24aand which have elasticity from an anchor point at the leading end portions to come in pressure contact with the switching plate54. Further, the contact base portion7fis provided with assembly bores7gon the other face thereof so that the assembly bores7galign with the leading end portions, namely the rise portions22b–24b, to fix contact members31–33on the rising portions22b–24b. Thus, it is possible to cotter the contact members31–33on the rise portions22b–24beasily by supporting the bottom sides of the rise portions22b–24bby the assembly jig inserted through the assembly bores7g.

Further, the bottom portion of the receiving depressed portion51aof the housing body51is provided with the depression to form the cavity K therein, thereby the leading end portions of the contact terminals22a–24a(the rise portions22b–24b) and the contact members31–33, which are exposed in the assembly bores7gto the housing body51, are electrically insulated from housing body51, which is made of conductor material. Thus, for instance, it is not necessary to form the assembly bores7gin relatively large lengths to secure electrical insulation between the contact terminals22a–24aand the contact members31–33, so that the assembly bores7gcan be formed in relatively small lengths and the contact base portion7fcan be formed in a relatively small thickness.

(7) The cavity K, provided in the depression formed in the housing body51, serves as the insulation portion; thereby a specific member for the insulation portion is not required, and the above-described effect (6) can be obtained by a relatively simple structure.

(8) The yoke housing4is formed in a relatively small thickness in the thickness direction Dt of the motor unit2(in the direction perpendicular to the flat portions4b), and the rotational axis of the worm wheel43is set in parallel to the thickness direction Dt of the motor unit2; thereby the gear housing41, which installs the worm wheel43therein, can be formed in a relatively small thickness in the thickness direction Dt of the motor unit2. Further, the fixed contacts (the contact terminals22a–24aand the contact members31–33) are disposed side by side on the plane in parallel with the flat portions4b; thereby the gear housing41can be formed in a relatively small thickness. Furthermore, it is possible to share a relatively large arranging space in the gear housing41in the width direction Dw of the motor unit2, thereby the electrical insulation among the fixed contacts can be easily secured.

(9) The fixed contacts are disposed side by side to extend approximately in parallel with one another (the contact terminals22a–24aare in parallel with one another, and the contact members31–33are in parallel with one another); thereby the fixed contacts can be installed in a relatively small space, and the fixed contacts can be penetrate through the communication hole51dformed in a relatively small size. Thus, it is possible to simplify a design of the housing body51of the gear housing41and to assemble the brush holder7and the gear housing41(the housing body51) easily.

(10) The connector portion7eis disposed at the side of the one arc portion4aof the yoke housing4, and, as schematically shown inFIG. 7, the outline of the connector portion7eis disposed within the range T (refer toFIG. 7) between the pair of the flat portions4bin the thickness direction Dt of the motor unit2. Thus, the connector portion7eallows a relatively small thickness of the motor apparatus1.

(11) In the fixed contacts (the contact terminals22a–24aand the contact members31–33), the base end portions31b–33bof the inclined portions31c–33care disposed at the one flat portion4bside with respect to the worm shaft42, that is, closer to the one flat portion4bthan to the other flat portions4b, which is coaxial to the rotational axis of the armature6. Thus, the fixed contacts can be easily disposed at the bottom portion side of the receiving depressed portion51a, so that the fixed contacts do not interfere with the worm wheel43in the thickness direction Dt of the motor unit2except the leading end portion31d–33d.

(12) The output shaft46is rotatably supported by the output shaft receiving portions51hformed in the housing body51. Thus, especially in such cases that the housing body51is made of aluminum alloy as in the present embodiment, the output shaft46can be supported easily and tightly as compared with a structure that the output shaft is supported by a cover fixed on a housing body. Further, the sector gear44is disposed at the opening side in the receiving depressed portion51awith respect to the worm wheel43, so that the fixed contacts are disposed over one face of the worm wheel43and the sector gear44is disposed over the other face of the worm wheel43. Thus, the fixed contacts do not interfere with the sector gear44, so that an arrangement of the fixed contacts and the sector gear44can be easily designed. Furthermore, it is possible to dispose the fixed contacts at the bottom portion side of the receiving depressed portion51ain assembling the yoke housing4, the housing body51and the brush holder7, and then to install the worm wheel43and the sector gear44step by step into the receiving depressed portion51a; thereby the assembly of the motor apparatus1becomes easy.

The above-described embodiment can be modified as in the following.

In the above-described embodiment, the contact terminals22a–24aand the contact members31–33form the fixed contacts. However, other constituents may form the fixed contact provided the fixed contacts are disposed in the brush holder7to extend through the communication hole51dinto the receiving depressed portion51aof the gear housing41. For example, the terminals22–24and the contact terminals31–33may be integrally formed, so that portions corresponding to the contact terminals22a–24aand the contact terminals31–33form the fixed contacts. In this structure, the number of parts can be reduced. Further, for example, portions of the terminals22–24corresponding to the contact terminals22a–24amay be formed separately from the other portions of the terminals22–24to be integrated in the contact terminals31–33. In this structure, the terminals22–24are not provided with the contact terminals22a–24a, and connected to the contact terminals31–33at positions outside the receiving depressed portion51aof the gear housing41.

The connector portion7e, which is formed in the brush holder7, is not limited to this structure, and may be separately formed from the brush holder7(holder body portion7b).

In the above-described embodiment, the connector portion7ehas a structure to be disposed at the same side as the worm wheel43with respect to the worm shaft42. However, the arrangement of the connector portion7eis not limited to this structure, and may be modified so that the connector portion7eand the worm wheel43interpose the worm shaft42therebetween (so that the connector portion7eand the worm wheel43are disposed at opposite sides from each other with respect to the worm shaft42).

In the above-described embodiment, the brush holder7has a structure to have the contact base portion7f, which is integrally formed with the holder body portion7bto extend through the communication hole51dinto the receiving depressed portion51aand support the fixed contacts. However, the present invention is not limited to this structure, and may be modified into other structures. For example, a contact base portion, which supports the fixed contacts, may be separately formed from the holder body portion and fixed to the brush holder to extend through the communication hole51dinto the receiving depressed portion51a. Alternatively, the contact base portion, which is separately formed from the holder body portion, may be fixed to the gear housing. Further, the brush holder may support the fixed contacts only outside the receiving depressed portion51aof the gear housing41.

In the above-described embodiment, the housing body51directly supports the contact base portion7f. However, the structure may be modified such that the contact base portion7fis not in direct contact with the housing body51.

In the above-described embodiment, the contact base portion7fis provided with the assembly bores7g. However, the configuration may be modified such that the contact base portion7fis not provided with the assembly bores7g. Further, the contact members31–33, which are fixed to the leading end portions of the contact terminals22a–24aby cottering in the above-described embodiment, may be alternatively fixed by spot welding and the like. In this case, the assembly bores7gmay be used to insert a jig for the spot welding.

In the above-described embodiment, the portion of the housing body51, which corresponds to the assembly bores7g, is provided with the depression to provide the cavity K, which serves as the insulation portion. However, the present invention is not limited to this structure, and the portion of the housing body51, which corresponds to the assembly bores7g, may be provided with other insulation portions formed by other members (for example, an insulation seal and the like).

In the above-described embodiment, the yoke housing4is formed in a flat shape, to be suitable for a motor of the wiper system installed inside a door of a vehicle. However, the shape of the yoke housing4is not limited to this structure and may be modified to a cylindrical one or others.

In the above-described embodiment, the fixed contacts are disposed side by side to extend in parallel to each other (the contact terminals22a–24aare in parallel to each other, and the contact members31–33are in parallel to each other). The contact members may be disposed to extend in different directions from each other. Further, the contact members31–33, which have an identical shape in the above-described embodiment, may have different shapes from each other such in their length.

The connector portion7eis not limited to be disposed at the side of the arc portion4aof the yoke housing4as in the above-described embodiment, and may be modified to be disposed at a side of the flat portion4bof the yoke housing in the thickness direction Dt of the motor unit2. Further, the connector portion7eis not limited to be disposed so that the outline G of the flat portion4bin the opposing direction is within the range T between the pair of the flat portions4bin the thickness direction Dt of the motor unit2, and may be disposed so that the outline G protrudes beyond the range T even when the connector portion7eis disposed at a side of the arc portion4a.

The housing body51is not limited to be made of aluminum alloy as in the above-described embodiment, and may be made of other metallic materials or electrical insulating resinous material. When the housing body51is made of electric insulating resinous material, the cavity K (the insulation portion) is not required.

The motor apparatus according to the present invention is not limited to the motor apparatus1for the rear wiper system as in the above-described embodiment, and can be naturally applied for a front wiper system. In this case, for example, the motor apparatus may be formed without the sector gear44and the distance keeping plate45to rotate an output shaft integrally with the worm wheel43, and the output shaft is connected to a front wiper via a link mechanism mounted on a vehicle. Further, the motor apparatus according to the present invention may be applied for systems other than a wiper system (such for a power window system and a sunroof system). Furthermore, the sector gear44, which connects the worm wheel43and the output shaft46, may be modified to other sub gear member such as a simple speed reduction gear in accordance with usage of the motor apparatus.