Technical Field
The present invention relates to a rotating electric machine having sealing structure, such as a motor for driving a power steering mechanism.
Background Art
Relatively small motors are mounted in automobiles in order to drive an oil pump, a power steering mechanism, or the like. In general, sand or dust on a road surface may adhere to the motor mounted in the automobile during traveling, and in rainy weather, the motor may often be exposed to rainwater. Thus, the life of the motor may be shortened due to the entry of those foreign matters into the motor. In view of the above, as a motor having structure for preventing the entry of the foreign matters such as water or dust into the motor (sealing structure), there is proposed a motor disclosed in, for example, Patent Literature 1.
The motor disclosed in Patent Literature 1 is a motor including a motor case including a cylindrical case body (yoke) being opened .at one end thereof and having a flange formed on an outer periphery of the opened end, and an end cover (housing) having a hollow portion and being held in abutraent on the flange. A recessed portion opened at a radially outer side of the motor case and the flange side is

formed in the end cover. A groove portion for sealing, which extends in a circuraferential direction of the case body and has both ends opened in the recessed portion, is formed in an end surface of the end cover held in abutment on the flange. A sealing resin is filled into the groove portion for sealing and the recessed portion of the end cover having an opening portion facing the case body side, which is closed by the flange f astened to the end cover. A gap between the flange and the end cover is sealed with this sealing resin. The filled sealing resin closes fine recessed portions formed in opposing surfaces of the end cover and the flange and fine gaps formed between abutment portions of the end cover and the flange, thereby sealing the gap between the end cover and the flange. In this manner, the sealing structure for preventing the entry of the foreign matters into the motor is attained.
Citation List
Patent Literature
[0003] [PTL 1] JP 2007-166682 A
Summary of Invention Technical Problem
[0004] In the motor disclosed in Patent Literature 1, the gap between the flange (case body) and the end cover is sealed with the filled sealing resin. However, depending on a pressure or time period for f illing the sealing resin, the sealing resin raay be leaked

out of the motor from an abutment surface. When the leaked sealing resin adheres to the end cover or the flange, an external appearance may be impaired. Further, when the sealing resin adheres during assembly work, work for removing the adhering sealing resin is additionally required, thus leading to a problem of degradation in workability.
[0005] The present invention has been made to solve the above-mentioned problems, and therefore has an object to provide a rotating electric machine having sealing structure, which is suppressed in adhesion of a sealing resin during assembly work and prevented from being impaired in external appearance.
Solution to Problem
[0006] According to one embodiment of the present invention, there is provided a rotating electric machine, including: a cylindrical yoke being opened at one end thereof and having a flange formed on an outer periphery of the opened end and a through hole formed in the flange, for allowing a fastening member to pass therethrough; a housing held in abutment on the outer periphery of the opened end so as to be fastened to the yoke with the fastening member, the housing having a recessed portion formed in an outer periphery on the yoke side and opened at a radialiy outer side and the yoke side; a grommet fitted into the recessed portion so as tobemountedon the housing; and a sealing resin filled in an abutment surface between the flange and the grommet, in which the fastening

mernber is positioned on one circuraferential side surface of the recessed portion, and in which a rib portion covering an outer periphery of an abutment surface to be held in abutment on the yoke is formed on another circumferential side surface of the recessed portion.
Advantageous Effects of Invention
[ 0007 ] According to the one embodiment of the present invention, it is possible toprovide the rotating electric machine having sealing structure, which is suppressed in adhesion of the sealing resin during assembly work and prevented from being impaired in external appearance.
Brief Description of Drawings
[0008] FIG. 1 is an exploded perspective view for illustrating a yoke 1, a housing 2, and a gromraet 3, which are used in a motor 100 according to a first embodiment of the present invention.
FIG. 2 is a perspective view for illustrating a state in which the yoke 1 is placed on the housing 2 in FIG. 1 so as to fasten the yoke 1 with screws 6.
FIG. 3 is an enlarged view of the vicinity of an extending portion 2f of the housing 2 in FIG. 2.
FIG. 4 is a view for illustrating a modification example of the yoke 1 in FIG. 1, specifically, an enlarged view of the vicinity of the extending portion 2f of the housing 2.

FIG. 5 is a view for illustrating a modification example of the grommet 3 in FIG. 1, specifically, a partial sectional view for illustrating the vicinity of an end surface on the yoke 1 side of the grommet 3.
FIG. 6 is a view for illustrating another modification example
of the grommet 3 in FIG. 1, specif ically, a partial sectional view
for illustrating the vicinity of an end surface on the yoke 1 side
of the grommet 3. .
FIG. 7 is a view for illustrating still another modification example of the grommet 3 in FIG. 1, specif ically, a partial sectional view for illustrating the vicinity of an end surface on the yoke 1 side of the grommet 3.
FIG. 8 is an exploded perspective view for illustrating a yoke 1, a housing 12, and a grommet 13, which are used in a rotating electric machine according to a second embodiment of the present invention.
FIG. 9 is an enlarged view of the vicinity of an abutment surface 13c of the grommet 13 in FIG. 8.
Description of Embodiment [0009] First Embodiment
Referring to the drawings, a first embodiment of the present invention is described below. In the drawings, the same or corresponding members and parts are denoted by the same reference symbols.

FIG. 1 is an exploded perspective view for illustrating a yoke 1, ahousing 2, and agrommet 3, which are used in a motor 100 according to the first embodiment of the present invention. FIG. 2 is a perspective view for illustrating a state in which the yoke 1 is placed on the housing 2 having the grommet 3 mounted thereon so that the yoke 1 and the housing 2 are fastened to each other. FIG. 3 is an enlarged view of the vicinity of an extending portion 2f of the housing 2.in FIG. 2.
[0010] In FIG. 1, thernotor 100 beinga rotating electricmachine includes the cylindrical yoke 1 being opened at one end thereof and having a flange lb formed on an outer periphery of an opened end la, the housing 2 held in abutment on the flange lb so as to be fastened to the yoke 1, and the grommet 3 for allowing connecting wires 5 such as lead wires accommodated in the housing 2 and led out from a body of the motor to pass therethrough. A plurality of through holes le for allowing screws 6 (fastening members) to pass therethrough in an axial direction are formed in the flange lb. [0011] A recessed portion 2a opened in two directions, specifically, at a radially outer side of the housing 2 and the yoke 1 side, is formed in an outer periphery on the yoke 1 side of the housing 2. A plurality of fastening holes 2b for fastening the screws 6 are formed at positions that correspond to the through holes le formed in the flange lb when the yoke 1 and the housing 2 are fastened to each other, and a fastening hole 2bl being one of the fastening holes 2b is formed in one circumferential side

surface 2c of the recessed portion 2a (left side in FIG. 3) . That is, a screw 6a (fastening member) is positioned on the one circumferential side surface 2c of the recessed portion 2a. A tray-like extending portion 2f (rib portion) for accumulating a sealing resin 4 leaked out of the motor 100 from an abutment surface 2e to be held in abutment on the flange lb is formed on another circumferential side surface 2d of the recessed portion 2a (right side in FIG. 3) (see FIG. 3). The extending portion 2f extends circumferentially from the another circumferential side surface 2d of the recessed portion 2a, and. is formed integrally with the housing 2. Note that, in FIG. 3, description is given of the case where the extending portion 2f has the tray-like shape so as to accumulate the sealing resin 4 leaked out from the abutment surface 2e, but the extending portion 2f is not limited to this case. The extending portion 2f only needs to cover an outer periphery of the abutment surface 2e between the another circumferential side surface 2d of the recessed portion 2a of the housing 2 and the flange lb of the yoke 1, and may be formed to cover the outer periphery of the abutment surface 2e and shaped to have a through hole in the axial direction without the bottom portion of the tray. [ 0012 ] The grommet 3 is formed of an insulating material having elasticity, such as rubber, and is formed integrally with an O-ring portion 3a as illustrated in FIG. 1. The O-ring portion 3a is arranged at a radially inner side of an end surface on the yoke 1 side of the housing 2. When the yoke 1 is placed on the housing 2 to bring

the flange lb into abutment on the housing 2, the O-ring 3a is squeezed to be deformed so that a gap between the yoke 1 and the housing 2 is sealed.
Further, the grommet 3 is mounted on the housing 2 by being fitted to the housing 2 under a state of being compressed inside the recessed portion 2a of the housing 2. A plurality of (two in the example of the figures) through holes 3b for allowing the connecting wires 5 to pass therethrough are formed in the grommet 3, and the connecting wires 5 are led out of the motor 100 through the through holes 3b.
An abutment surface 3c on which the flange lb is brought into abutment is formed on an end surface on the yoke 1 side of the grommet
3, and the sealing resin 4 is filled at a radially inner side of the abutment surface 3c. The flange lb and the grommet 3 are brought into abutment on each other, thereby sealing a portion of the abutment surface 3c, which is filled with the sealing resin 4 (radially inner side of the abutment surface 3c). Further, a recessed portion 3d recessed at the radially outer side with respect to. the portion of the abutment surface 3c, which is filled with the sealing resin
4, is formed in the end surface on the yoke 1 side of the grommet 3. The recessed portion 3d illustrated in FIG. 3 is covered by the flange lb at a part {radially inner side) of the recessed portion 3d. The sealing resin 4 leaked out from the abutment surface 3c is accumulated in the recessed portion 3d.
[0013] Next, referring to FIG. 1 and FIG. 2, description is

given of an overview of a procedure of asseinbling the motor 100. The grommet 3 is fitted into the recessed portion 2a of the housing 2 so that the grommet 3 is mounted on the housing 2 together with a brush holder (not shown).
After the grommet 3 is mounted on the housing 2, the molten' sealing resin 4 is applied to the radially inner side of the abutment surface 3c of the grommet 3 (vicinity of the O-ring 3a in the example of the figures) . In this manner, work for filling the resin in the abutment surface 3c between the flange lb and the grommet 3 is performed. Finally, as illustrated in FIG. 2, the yoke 1 is placed on the housing 2 to bring the flange lb into abutment on the housing 2 and the abutment surface 3c of the grommet 3, and the yoke 1 and the housing 2 are fastened with the screws 6. In this manner, the motor 100 is assembled. In the assembled motor 100, a gap between the yoke I and the grommet 3 is sealed with the sealing resin 4 filled in the abutment surface 3c of the grommet 3. Further, the gap between the yoke 1 and the housing 2 is sealed by the O-ring 3a formed integrally with the grommet 3. Note that, in the first embodiment, description is given of the case where the gap between the yoke 1 and the housing 2 is sealed by the O-ring 3a. However, in order to more reliably seal the gap, the sealing resin 4 may also be applied to an abutment surface between the yoke 1 and the housing 2 (including the abutment surface 2e between the flange lb and the another circumferential side surface 2d of the recessed portion 2a) . In this case, the gap between the yoke 1 and the housing

2 and the gap between the yoke 1 and the grommet 3 are each sealed
with the sealing resin 4.
[0014] As the sealing oil and fat 4, it is preferred to use the sealing resin 4 excellent in close-contact property and water resistance, which is required in the sealing structure. For example, it is preferred to use a silicone resin. [0015] As described above, the motor 100 (rotating electric rnachine} according to the first embodiment of the present invention includes: the cylindrical yoke 1 being opened at one end thereof and having the flange lb formed on the outer periphery of the opened end; the housing 2 held in abutment on the flange lb so as to be fastened to the yoke 1 with the screw 6 (fastening member), the housing having the recessed portion 2a formed in the outer periphery on the yoke 1 side and opened at the radially outer side and the yoke 1 side; the grommet 3 fitted into the recessed portion 2a so as to be mounted on the housing 2; and the sealing resin 4 filled in the abutment surface 3c between the flange lb and the grommet
3 . The screw 6a is positioned on the one circumferential side surface
2c of the recessed portion 2a (left side in FIG. 3} . The extending
portion 2f (rib portion) covering the outer periphery of the abutment
surface 2e to be held in abutment on the yoke 1 is formed on the
another circumferential side surface 2d of the recessed portion
2a (right side in FIG. 3). Thus, when the yoke 1 is placed on the
housing 2 under the state in which the grommet 3 is mounted on the
housing 2 and the sealing resin 4 is filled in the abutment surface

3c between the flange lb and the grornmet 3 to bring the flange lb into abutment on the housing 2 and the abutment surface 3c of the grommet 3, and the yoke 1 is fastened with the screws 6 so that the yoke 1 is mounted on the housing 2, the sealing resin 4 flows radially and circumferentially on the end surface (abutment surface 3c) of the grommet 3, and a part of the sealing resin 4 is leaked out of the motor 100 from the abutment surface 2e. However, the leaked sealing resin 4 is covered by the extending portion 2f, thereby suppressing adhesion of the sealing resin 4 during assembly work. Further, the leaked sealing resin 4 does not adhere to other parts, thereby being capable of providing a rotating electric machine prevented from being impaired in external appearance. [0016] In this case, when the yoke 1 is placed on the housing 2 under a state in which the sealing resin 4 is filled in the abutment surface 3c of the grommet 3 so that the flange lb is only held in abutment on the abutment surface 3c of the grommet 3, the sealing resin 4 uniformly flows over radially or circumferentially without fiowing to a specific radial position or a specific circumf erential. position in a biased manner. However, in the first embodiment of the present invention, the extending portion 2f covering the outer periphery of the abutment surface 2e between the another circumferential side surface 2d of the recessed portion 2a and the yoke 1 is provided on the side opposite to the side of the one circumferential side surface 2c of the recessed portion 2a, on which the screw 6a serving as the fastening member is positioned. Thus,

through the fastening with the screw 6a, the fastening force of the screw 6a acts. As a result, as indicated by the thick arrow in FIG. 3, most of the sealing resin 4 filled in the abutment surface 3c flows fromthe (one) circumferential side surface 2c of the recessed portion 2a on the side on which the screw 6a is fastened to the (another) circumferential side surface 2d on the side opposite to the side of the circumferential side surface 2c. The sealing resin 1 4 leaked out from the abutment surface 2e is covered by the extending portion 2f formed on the (another) circumferential side surface 2d. Thus, it is possible to reliably cover most of the sealing resin 4 leaked out of the motor 100.
[ 0017 ] Further, according to the first embodiment of the present invention, the extending portion 2f covering the outer periphery of the abutment surface 2e is formed integrally with the housing 2, and hence the extending portion 2f can be formed only by changing a shape of a die for molding the housing 2. Thus, it is possible to provide a rotating electric machine that is prevented from significant cost increase, suppressed in adhesion of the sealing resin 4 during the assembly work, and is not impaired in external appearance. Note that, regarding the extending portion 2f, FIG. 3 is an illustration of the case where the extending portion extending circumf erentially from the vicinity of the radial center of the another circumferential side surface 2d of the recessed portion 2a is formed, but the extending portion 2f is not limited tothis case. The extending portion only needs to cover the outer periphery of the abutment surface

2e between the another circumf erential side surf ace 2d of the recessed portion 2a and the yoke 1, and to extend circumferentially from the another circumferential side surface 2d of the recessed portion 2a. The abutment surface 2e is positioned on the flange lb side
(radially inner side) of the another circumferential side surface of the recessed portion. Thus, for example, the extending portion may be formed to extend circumferentially from a radially outer side of the another circumferential side surface of the recessed portion.
[0018] Note that, in the first embodiment of the present invention, description is given of the case where the extending portion 2f formed on the another circumferential side surface 2d of the recessed portion 2a of the housing 2 has the tray-like shape so as to accumulate the sealing resin 4 leaked out from the abutment surface 2e, but the extending portion 2f is not limited to this case. The extending portion 2f only needs to have structure covering the outer periphery of the abutment surface between the another circumferential side surface 2d of the housing 2 and the yoke 1, and for example, there may be formed an L-shaped extending portion circumferentially protruding from the radially inner side of the another circumferential side surface 2d of the housing 2 and extending toward the yoke 1 side in the axial direction so as to cover the outer periphery of the abutment surface between the another circumferential side surface 2d of the housing 2 and the yoke 1. In this case, the sealing resin 4 is leaked out of the motor 100

from the abutment surface 2e, but similarly to the case of the tray of the extending portion 2f described in the first embodiment of the present invention, the leaked sealing resin 4 is accumulated in a gap formed by the another circumferential side surface 2d of the housing 2 and the L-shaped extending portion, thereby suppressing the adhesionof the sealing resin 4 during the assemblywork. Further, the leaked sealing resin 4 does not adhere to other parts, thereby being capable of providing the rotating electric machine prevented from being impaired in external appearance.
[0019] Further, in the related art, reliable sealing between the yoke and the housing can be confirmed by confirming the leakage of the sealing resin from the abutment surface between the yoke and the housing. On the other hand, the leakage of the sealing
resin 4 to the extending portion 2f can be confirmed by observing the extending portion 2f from the yoke 1 side in the axial direction. Therefore, the reliable sealing between the yoke 1 and the housing 2 can be confirmed irrespective of the presence/absence of the extending portion 2f. Note that, the extending portion 2f illustrated in FIG. 3 is formed to extend circumferentially, and hence, when a worker touches the extending portion 2f from the yoke 1 side in the axial direction, the sealing resin 4 leaked out from the abutment sur face 2emay adhere dur ing the assembly work- However, as illustrated in FIG. 4, a protruding portion Id protruding radially outward so as to cover an end surface on the yoke 1 side of the extending portion 2f is formed on an outer periphery of the flange

lb of the yoke 1, and hence the protruding portion Id functions as a cover for the extending portion 2f. Thus, the worker does not touch the extending portion 2f from the axial direction, thereby further suppressing the adhesion of the sealing resin 4 during the assembly work. Further, the leaked sealing resin 4 does not adhere to other parts, thereby being capable of providing the rotating electric machine prevented from being impaired in external appearance.
[0020] Further, accordingto the first embodiraent of the present invention, as illustrated in FIG. 3, the recessed portion 3d recessed at the radially outer side with respect to the portion of the abutment surface 3c, which is filled with the sealing resin 4, is formed in the end surface on the yoke 1 side of the grommet 3. Thus, when the flange lb is brought into abutment on the abutment surface 3c of the grommet 3 under the state in which the grommet 3 is mounted on the housing 2 and the sealing resin 4 is filled in the abutment surface 3c so that the yoke 1 is mounted on the housing 2, the sealing resin 4 is leaked out of the motor 100 from the abutment surface 3c. However, the leaked sealing resin 4 flows into the recessed portion 3d, thereby suppressing the adhesion of the sealing resin 4 during the assembly work. Further, the leaked sealing resin 4 does not adhere to other parts, thereby being capable of providing the rotating electric machine prevented from being impaired in external appearance. The radially inner sideof the recessedportion 3d is covered by the flange lb, and hence, when the amount of the

sealing resin 4 leaked out of the motor 100 from the abutment surface 3c of the grommet 3 is small, the leaked sealing resin 4 itself is accumulated in space formed by the flange lb and the recessed portion 3d. Thus, it is possible to provide the rotating electric machine f urther prevented from being impaired in external appearance . Note that, when the amount of the sealing resin 4 leaked out of the motor 100 from the abutment surface 3c of the grommet 3 is relatively large due to fluctuation in amount of filling the sealing resin 4 or the like, the leaked sealing resin 4 is accumulated in a portion of the recessed portion 3d on the radially outer side with respect to the flange lb, and the accumulation of the sealing resin 4 in the recessed portion 3d can be confirmed by observing the recessed portion 3d from the yoke 1 side in the axial direction, thereby being capable of confirming the reliable sealing between the yoke 1 and the grommet 3.
[0021] Note that, FIG. 3 is an illustration of the case where the recessed portion 3d recessed at the radially outer side with respect to the abutment surface 3c of the grommet 3 is formed, the recessed portion 3d is covered by the flange lb at a part on the radially inner side with respect to the flange lb, and the other part of the recessed portion 3d is positioned on the radially outer side with respect to the flange lb. However, the present invention is not limited to this case, and only needs to have structure with a recessed portion recessed at the radially outer side with respect to the portion of the abutment surface 3c, which is filled with

the sealing resin 4 . There may be employed such structure that an entire recessed portion 3dl is formed to be positioned on the radially outer side with respect to the flange lb (see FIG. 5}, or structure that an entire recessed portion 3d2 is positioned on the radially inner side with respect to the flange lb so that the entire recessed portion 3d2 is covered by the flange lb (see FIG. 6). As illustrated in FIG. 5, in the case of the structure that the entire recessed portion 3dl is formed to be positioned on the radially outer side with respect to the flange lb, the leaked sealing resin 4 is accumulated in the recessed portion 3dl, and the accumulation of the sealing resin 4 in the recessed portion 3dl can be confirmed by observing the recessed portion 3dl from the yoke 1 side in the axial direction, thereby being capable of confirming the reliable sealing between the yoke 1 and the grommet 3. As illustrated in FIG. 6, in the case of the structure that the entire recessed portion 3d2 is positioned on the radially inner side with respect to the flange lb so that the entire recessed portion 3d2 is covered by the flange lb, the sealing resin 4 itself that may be leaked out is reliably accumulated in space formed by the flange lb and the recessed portion 3d2. Thus, it is possible to provide the rotating electric machine further prevented from being impaired in external appearance.
[0022] Further, in the first embodiment of the present invention, description is given of the case where the recessed portion 3d recessed at the radially outer side with respect to the portion of the abutment

surface 3c, which is filled with the sealing resin 4, is formed in the end surface on the yoke 1 side of the grommet 3, but the present invention is not limited to this case. As illustrated in FIG. 7, there may be formed a projecting portion 3e being positioned on the radially outer side with respect to the flange lb formed on the outer periphery of the opened end of the yoke 1 and extending in the axial direction. In this case, the sealing resin 4 is leaked out of the motor 100 from the abutment surface 3cr but the leaked sealing resin 4 is accumulated in a gap formed by the end surface on the yoke 1 side of the grommet 3 and the projecting portion 3e, thereby suppressing the adhesion of the sealing resin 4 during the assembly work. Further, the leaked sealing resin 4 does not adhere to other parts, thereby being capable of providing the rotating electric machine prevented from being impaired in external appearance. [0023] Second Embodiment
In the above-mentioned first embodiment, description is given of the case where the rib portion (extending portion 2f) covering the outer periphery of the abutment surface between the another circumferential side surface 2d of the housing 2 and the yoke 1 is formed on the housing 2 . On the other hand, in a second embodiment of the present invention, referring to FIG. 8 and FIG. 9, description is given of a case where a portion corresponding to the extending portion 2f is formed on a grommet 13 in the above-mentioned first embodiment. FIG. 8 is an exploded perspective view of a motor 200

according to the second embodiment of the present invention, and FIG. 9 is an enlarged view of the vicinity of the grommet 13. [0024] In FIG. 8, themotor 200 being a rotating electric machine includes a cylindrical yoke 1 being opened at one end thereof and having a flange lb formed on an outer periphery of an opened end la, a housing 12 held in abutment on the flange lb so as to be fastened to the yoke 1, and the grommet 13 for allowing connecting wires 5 such as lead wires accommodated in the housing 12 and led out from a body of the motor 200 to pass therethrough. A plurality of through holes le for allowing screws 6 (fastening members) to pass therethrough in an axial direction are formed in the flange lb. Further, the flange lb is held in abutment on an abutment surface 12e of the housing 12.
[0025] A recessed portion 12a opened in two directions, specifically, at a radially outer side of the housing 12 and the yoke 1 side, is formed in an outer periphery on the yoke 1 side of the housing 12, and a screw 6a (fastening member) is positioned on one circumferential side surface 12c of the recessed portion 12a (left side in FIG. 8) . Further, a plurality of fastening holes 12b for fastening the screws 6 are formed at positions that correspond to the through holes le formed in the flange lb when the yoke 1 and the housing 12 are fastened to each other.
[0026] The grommet 13 is formed of an insulating material having elasticity, such as rubber, and is formed integrally with an O-ring portion 13a as illustrated in FIG. 8. The O-ring portion 13a is

arranged at a radially inner side of an end surface on the yoke 1 side of the housing 12. When the yoke 1 is placed on the housing 12 to bring the flange lb into abutment on the housing 12, the O-ring 13a is squeezed to be deformed so that a gap between the yoke 1 and the housing 12 is sealed.
Further, the grommet 13 is mounted on the housing 12 by being fitted to the housing 12 under a state of being compressed inside the recessed portion 12a of the housing 12. A plurality of (two in the example of the figures} through holes 13b for allowing the connecting wires 5 to pass therethrough are forrrted in the grommet 13, and the connecting wires 5 are led out of the motor 200 through the through holes 13b.
Further, an abutment surface 13c on which the flange lb is brought into abutment is formed on an end surface on the yoke 1 side of the grommet 13, and a sealing resin 4 is filled at a radially inner side of the abutment surface 13c (vicinity of the O-ring 13a in the example of the figures). The flange lb and the grommet 13 are brought into abutment on each other, thereby sealing the abutment surface 13c. Further, a recessedportion 13drecessedat the radially outer side with respect to the abutment surface 13c is formed in the end surface on the yoke 1 side of the grommet 13 at the radially outer side with respect to the abutment surface 13c. Similarly to the case of the recessed portion 3d illustrated in FIG. 3, the sealing resin 4 leaked out from the abutment surface 13c between the flange lb and the grommet 13 is accumulated in the recessed portion 13d.

[0027] Further, a tray-like extending portion 13g {rib portion) for accumulating the sealing resin 4 leaked out of the motor 200 from the abutment surface 12e between the housing 12 and the flange lb is formed on a circumferential side surface of the grommet 13 being a circumferential side surface on a side on which the grommet 13 is fitted to another circumferential side surface 12d of the recessed portion 12a of the housing 12, namely, on another circumferential side surface 13f of the grommet 13 (right side in FIG. 9) (see FIG. 9) . The extending portion 13g extends circumferentially from the another circumferential side surface 13f of the grommet 13, and is formed integrally with the grommet 13, Note that, in FIG. 9, description is given of the case where the extending portion 13g has the tray-like shape so as to accumulate the sealing resin 4 leaked out from the abutment surface 12e, but the extending portion 13g is not limited to this case . The extending portion 13g only needs to cover an outer periphery of the abutment surface 12e between the another circumferential side surface 12d of the recessed portion 12a of the housing 12 and the flange lb of the yoke 1, and may be formed to cover the outer periphery of the abutment surface 12e and shaped to have a through hole in the axial direction without the bottom portion of the tray. [0028] As described above, the motor 200 (rotating electric machine) according to the second embodiment of the present invention includes: the cylindrical yoke 1 being opened at one end thereof and having the flange lb formed on the outer periphery of the opened

end; the housing 12 held in abutment on the flange lb so as to be fastened to the yoke 1 with the screw 6 (fastening member) , the housing having the recessed portion 12a f ormed in the outer periphery on the yoke 1 side and opened at the radially outer side and the yoke 1 side; the gromrnet 13 fitted into the recessed portion 12a so as to be mounted on the housing 12; and the sealing resin 4 filled in the abutment surface 13c between the flange lb and the gromrnet 13. The screw 6a is positioned on the one circumferential side surface 12c of the recessed portion 12a (left side in FIG. 9) . The extending portion 13g {rib portion) covering the outer periphery of the abutment surface 12e to be held in abutment on the yoke 1 is formed on the another circumferential side surface 12d of the recessed portion 12a (right side in FIG. 9) . Thus, when the yoke 1 is placed on the housing 12 under the state in which the gromrnet 13 is mounted on the housing 12 and the sealing resin 4 is filled in the abutment surface 13c between the flange lb and the gromrnet 13 to bring the flange lb into abutment on the housing 12 and the abutment surface 13c of the gromrnet 13, and the yoke 1 is fastened with the screws 6 so that the yoke 1 is mounted on the housing 12, the sealing resin 4 flows radially and circumferentially on the end surface (abutment surface 13c) of the gromrnet 13, and a part of the sealing resin 4 is leaked out of the motor 200 from the abutment surface 12e. However, the leaked sealing resin 4 is covered by the extending portion 13g, thereby suppressing adhesion of the sealing resin 4 during assembly work. Further, the leaked sealing resin

4 does not adhere to other parts, thereby being capable of providing a rotating electricmachineprevented frombeing impaired in external appearance.
[0029] In this case, when the yoke 1 is placed on the housing 12 under a state in which the sealing resin 4 is filled in the abutment surface 13c of the grommet 13 so that the flange lb is only held in abutment on the abutment surface 13c of the grommet 13, the sealing resin 4 uniformly flows over radially or circumferentially without flowing to a specific radial position or a specific circumferential position in a biased manner. However, in the second embodiment of the present invention, the extending portion 13g covering the outer periphery of the abutment surface 12e between the another circumferential side surface 12d of the recessed portion 12a and the yoke 1 is provided on the side opposite to the side of the one circumferential side surface 12c of the recessed portion 12a, on which the screw 6a serving as the fastening member is positioned. Thus, through the fastening with the screw 6a, the fastening force of the screw 6a acts. As a result, similarly to the case of the above-mentioned first embodiment, most of the sealing resin 4 filled in the abutment surface 13c flows from the (one) circumferential side surface 12c of the recessed portion 12a on the side on which the screw 6a is fastened to the (another) circumferential side surf ace 12d on the side opposite to the side of the circumferential side surface 12c. The sealing resin 4 leaked out from the abutment surface 12e is covered by the extending portion 13g formed on the (another)

circumferential side surface 12d. Thus, it is possible to reliably cover most of the sealing resin 4 leaked out of the motor 100. [0030] Further, in the f irst embodiment of the present invention, the extending portion 2f covering the outer periphery of the abutment surface 2e is formed integrally with the housing 2, and the shape of the housing 2 and the positions of the fastening holes 2b differ depending on the specif ications of the motors . Thus, each die needs to be changed, with the result that the costs may be increased. On the other hand, according to the second embodiment of the present invention, the extending portion 13g covering the outer periphery of the abutment surface 12e is formed integrally with the grommet 13, and hence, even when the shape of the housing 12 and the positions of the fastening holes 12b differ depending on the specifications of the motors, a common grommet 13 changed only in shape of the grommet 13 can be used in each motor. Thus, the cost increase can be suppressed, and the configuration according to the second embodiment is adaptable to the specifications of a plurality of motors.
[0031] Note that, in the second embodiment of the present invention, description is given of the case where the extending portion 13g extending circumferentially from the another circumferential side surface 13f of the grommet 13 has the tray-like shape so as to accumulate the sealing resin 4 leaked out from the abutment surface 12e, but the extending portion 13g is not limited to this case. The extending portion 13g only needs to have structure

covering the outer periphery of the abutment surface between the another circumferential side surface 12d of the housing 12 and the yoke 1. For example, there may be formed an extending portion extending circumferentially along the housing 12 from a radially inner side of the another circumferential side surface 13f of the grommet 13, and the extending portion may have formed thereon a projecting portion extending toward the yoke 1 side in the axial direction so as to cover the outer periphery of the abutment surface between the another circumferential side surface 12d of the housing 12 and the yoke 1. In this case, the sealing resin 4 is leaked out of the motor 200 from the abutment surface 12e, but similarly to the case of the tray of the extending portion 13g described in the second embodiment of the present invention, the leaked sealing resin 4 is accumulated in a gap formed by the another circumferential side surface 12d of the housing 12 and the extending portion and the projecting portion of the grommet 13, thereby suppressing the adhesion of the sealing resin 4 during the assembly work. Further, the leaked sealing resin 4 does not adhere to other parts, thereby being capable of providing the rotating electric machine prevented from being impaired in external appearance.
[0032] Further, in the reiated art, reliable sealing between the yoke and the housing can be confirmed by confirming the leakage of the sealing resin from the abutment surface between the yoke and the housing. On the other hand, the leakage of the sealing resin 4 to the extending portion 13g can be confirmed by observing

the extending portion 13g from the yoke 1 side in the axial direction. Therefore, the reliable sealing between the yoke 1 and the housing
12 can be confirmed irrespective of the presence/absence of the
extending portion 13g.
[0033] Further, according to the second embodiment of the present invention, as iliustrated in FIG. 9, the recessed portion 13d recessed at the radially outer side with respect to the portion of the abutment surface 13c, which is filled with the sealing resin 4, is formed in the end surface on the yoke 1 side of the grommet 13. Thus, when the f lange lb is brought into abutment on the abutment surface 13c of the grommet 13 under the state in which the grommet
13 is mounted on the housing 12 and the sealing resin 4 is filled
in the abutment surface 13c so that the yoke 1 is mounted on the
housing 12, the sealing resin 4 is leaked out of the motor 200 from
the abutment surface 13c. However, the leaked sealing resin 4 flows
into the recessed portion 13d, thereby suppressing the adhesion
of the sealing resin 4 during the assembly work. Further, the leaked
sealing resin 4 does not adhere to other parts, thereby being capable
of providing the rotating electric machine prevented from being
impaired in external appearance. The radially inner side of the
recessed portion 13d is covered by the flange lb, and hence, when
the amount of the sealing resin 4 leaked out of the motor 200 from
the abutment surface 13c of the grommet 13 is small, the leaked
sealing resin 4 itself is accumulated in space formed by the flange
lb and the recessed portion 13d. Thus, it is possible to provide

the rotating electric machine further prevented from being impaired in external appearance. Note that, when the amount of the sealing resin 4 leaked out of the motor 200 from the abutment surface 13c of the grommet 13 is relatively large due to fluctuation in amount of fill ing the sealing resin 4 or the like, the leaked sealing resin 4 is accumulated in a portion of the recessed portion 13d on the radiallyouter sidewithrespect to the flange lb, and the accumulation of the sealing resin 4 in the recessed portion 13d can be confirmed by observing the recessed portion 13d from the yoke 1 side in the axial direction, thereby being capable of confirming the reliable sealing between the yoke 1 and the grommet 13.
[0034] Note that, regarding the rib portion covering the outer periphery of the abutment surface to be held in abutment on the yoke 1, which is formed on the another circumferential side surface 2d or 12d of the recessed portion 2a or 12a of the housing 2 or 12, in the first embodiment of the present invention, description is given of the case of the extending portion 2f extending circumferentially from the another circumferential side surface 2d of the recessed portion 2a of the housing 2, and in the second embodiment of the present invention, description is given of the case of the extending portion 13g extending circumferentially from, of the circumferential side surfaces of the grommet 13, the another circumferential side surface 13f on the side on which the grommet 13 is fitted to the another circumferential side surface 12d of the recessed portion 12a. However, the rib portion is not limited

to those cases, and there may be formed an L-shaped rib portion protruding radially outward from the yoke 1 and extending toward the housing 2 side in the axial direction so as to cover the outer periphery of the abutment surface between the (another) circumferential side surface 2d of the housing 2 and the yoke 1. Also in this case, the sealing resin 4 leaked out of the motor is covered by the rib portion, thereby suppressing the adhesion of the sealing resin 4 during the assembly work. Further, the leaked sealing resin 4 does not adhere to other parts, thereby being capable of providing the rotating electric machine prevented from being impaired in external appearance.
[0035] Further, in the first and second embodiments of the present invention, the general motor 100 is described as the rotating electric machine. However, the rotating electric machine is not limited to this motor, and may be another rotating electric machine such as a brush motor, a brushless motor, or an alternator.
Reference Signs List
[0036] 1: yoke, la: opened end, lb: flange, le: through hole, Id: protruding portion, 2, 12: housing, 2a, 12a: recessed portion, 2b, 2bl: fastening hole, 2c, 2d, 12c, 12d: circumferential side surface, 2e, 12e: abutment surface, 2f: extending portion (rib portion), 3, 13: grommet, 3c, 13c: abutment surface, 3d, 3dl, 3d2, 13d: recessed portion, 3e: projecting portion, 4: sealing resin, 6, 6a: screw (fastening member) , 13f: circumferential side surface,

13g: extending portion (rib portion), 100, 200: motor (rotating electric machine)

We Claim:
[Claim 1] A rotating electric machine, comprising:
a cylindrical yoke (1) being opened at one end thereof and having a flange (1b) formed on an outer periphery of the opened end;
a housing (2) held in abutment on the flange so as to be fastened to the yoke with a fastening member, the housing (2) having a recessed portion (2a) formed in an outer periphery on the yoke side and opened at a radially outer side and the yoke side;
a grommet (3) fitted into the recessed portion (2a) so as to be mounted on the housing; and
a sealing resin (4) filled in an abutment surface (3c) between the flange and the grommet (3),
wherein the fastening member is positioned on one circumferential side surface of the recessed portion, and
wherein a rib portion (2f) covering an outer periphery of an abutment surface to be held in abutment on the yoke is formed on another circumferential side surface of the recessed portion.
[Claim 2] A rotating electric machine according to claim 1, wherein the rib portion (2f) comprises an extending portion extending circumferentially from the another circumferential side surface of the recessed portion.
[Claim 3] A rotating electric machine according to claim 1, wherein the rib portion (2f) comprises an extending portion extending circumferentially from one of circumferential side surfaces of the grommet (3) on a side on which the

grommet is fitted to the another circumferential side surface of the recessed portion.
[Claim 4] A rotating electric machine according to any one of claims 1 to 3, wherein a recessed portion recessed at the radially outer side with respect to the abutment surface to be held in abutment on the flange of the yoke is formed in an end surface on the yoke side of the grommet (3).
[Claim 5] A rotating electric machine according to any one of claims 1 to 3, wherein a projecting portion (3e) extending in an axial direction is formed on an end surface on the yoke side of the grommet (3) so as to be positioned on the radially outer side with respect to the outer periphery of the opened end of the yoke.
[Claim 6] A rotating electric machine according to any one of claims 1 to 5, wherein a protruding portion (1d) protruding radially outward so as to cover an end surface on the yoke side of the rib portion is formed on an outer periphery of the flange of the yoke (1).