JP2002095207A - Sealing structure of motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain good sealing characteristic event for the portion where a flange is not formed, namely for the internal end portion of a grommet concerning the interface between a bracket and a yoke. SOLUTION: In the seal structure of a motor, the grommet 13 for guiding a lead wire is provided at the interface between the bracket 11 and yoke, the grommet is integrally provided with an O-ring 14 and the O-ring is held at the interface between the bracket and yoke to seal these element. A thinner portion 18ab forming a wall to prevent fall toward the internal side of the grommet is provided at the position opposing to the internal end surface of the grommet 13. The thinner portion 18ab is provided between a brush holder fitted to the bracket and a magnet fitted at the internal circumference of the yoke, and is integrally mounted to a spacer 18 for keeping an interval between these elements to the predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure for an electric motor suitable for use in electric components mounted on a vehicle or the like.

[0002]

2. Description of the Related Art As shown in FIGS. 6 to 8, a seal between a bracket 1 and a yoke 2 is used for a small-sized electric motor of this type using an integrated grommet and O-ring. There is something to do.

That is, a grommet 3 for leading a lead wire is interposed on the mating surface of the bracket 1 and the yoke 2, and an O-ring 4 is integrally formed on the grommet 3.
In some cases, the ring 4 is sandwiched between the mating surfaces of the bracket 1 and the yoke 2 to seal between the two. A cutout groove 1a for inserting a grommet is formed on the mating surface of the bracket 1 with the yoke 2. In addition, the same bracket 1
A flange 1b is formed at a portion of the mating surface with the yoke 2 except for the cutout groove 1a, and the O-ring 4 is disposed outside a base of the flange 1b.

[0004]

In the conventional electric motor seal structure described above, as shown in FIG. 8, an O-ring is formed by an inclined portion 2a formed on a mating surface of the yoke 2 with the bracket 1. 4 and the upper step portion 3a formed in the upper inner portion following the O-ring 4 of the grommet 3 is pressed obliquely downward and inward as indicated by an arrow F in the figure, whereby the O-ring 4 and the grommet 3 Utilizing the elasticity, a sealing property between the bracket 1 and the yoke 2 is ensured.

Here, the bracket 1 has a flange 1b.
Although a good sealing property can be obtained by pressing the O-ring 4 against the flange 1b, the portion where the flange 1b is not formed, that is, the inner end portion of the grommet 3 It is pushed by the inclined part 2a and falls down as it is,
As a result, there is a problem that good sealing properties cannot be obtained.

The present invention has been made in view of the above-mentioned problems of the prior art,
It is an object of the present invention to provide a seal structure of an electric motor in which a good seal can be obtained even at a portion where a flange is not formed, that is, at an inner end portion of a grommet.

[0007]

Means for Solving the Problems To solve the above problems, the present invention employs the following means. Claim 1
In the present invention described above, a grommet for leading a lead wire is interposed on the mating surface of the bracket and the yoke, an O-ring is formed integrally with the grommet, and the O-ring is sandwiched between the mating surfaces of the bracket and the yoke. In the seal structure of the electric motor for sealing between the two, the grommet is provided with a wall at a position facing the inner end face of the grommet to prevent the grommet from falling inward. In the invention according to claim 2, the wall is interposed between a brush holder attached to the bracket and a magnet attached to the inner periphery of the yoke, and is integrally attached to a spacer that keeps a predetermined interval between the two. It is characterized by having. The invention according to claim 3 is characterized in that a vertical rib protruding from the inner end surface of the grommet is formed so as to extend in a direction perpendicular to the mating surface of the bracket and the yoke.

In the present invention, the grommet is provided with a wall for preventing the grommet from falling inward at a position facing the inner end surface of the grommet as described above. Therefore, when the grommet is pushed by the yoke, the grommet is inward. It comes into strong contact with the yoke with the back supported by the wall without falling down. Therefore, a good sealing property between the grommet and the yoke, which has conventionally been difficult to obtain a good sealing property, is secured.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. 1 is a perspective view showing a main part of a seal structure of an electric motor according to the present invention, FIG. 2 is an exploded perspective view showing the seal structure, FIG. 3 is a sectional view of the seal structure, and FIG. 4 shows an inner end surface of a grommet. FIG. 5 is a perspective view, and FIG. 5 is a sectional view showing various shapes of an upper portion of an inner end surface of the grommet.

In FIG. 1, reference numeral 11 denotes a bracket,
A yoke 2 is attached to the bracket 11 with fixing means such as screws (see FIG. 4). The yoke 12 has a bottomed cylindrical shape to which a magnet 17 is fixed on the inner peripheral surface (see FIG. 2). An armature (not shown) is rotatably supported between the bracket 11 and the yoke 12. At the joint between the cylindrical portion 12a and the flange portion 12b of the yoke 12, an inclined portion 12c that is inclined at approximately 45 degrees and connects the two is formed.

A grommet 13 for leading out a lead wire is interposed on the mating surface of the bracket 11 and the yoke 12,
An O-ring 14 is formed integrally with the grommet 13. The grommet 13 and the O-ring 14 are sandwiched between the mating surfaces of the bracket 11 and the yoke 12, so that the gap between the two 11 and 12 is sealed.

The grommet 13 is formed in a substantially rectangular parallelepiped shape by a suitably elastic resin material, and has continuous ridges 13a formed on both left and right side surfaces and a bottom surface. Notch groove 11
a into the concave portion 11aa formed on the inner surface of
The positioning of the grommet 13 with respect to the bracket 11 and the good sealing properties are ensured.

The grommet 13 is formed integrally with the O-ring 14 with the O-ring 14 mounted on the upper surface thereof. The O-ring 14 is formed flush with the height of the O-ring 14 so as to protrude upward not only at a portion that is continuous with the ring 14 but also at a portion that invades the O-ring 14.

On the inner end surface of the grommet 13, a plurality of vertical ribs 13 c extending in a direction perpendicular to the mating surface of the bracket 11 and the yoke 12 and projecting laterally (in the circumferential direction along the O-ring 14). ) Formed at intervals.
At least the upper portion of the vertical rib 13c is cut out in a tapered shape. The grommet 13 is formed with a through hole 13d extending from the inner end surface to the outer end surface.
A lead 15 for supplying power to the armature is inserted through 3d.

A cutout groove 11a for inserting a grommet is formed on a surface of the bracket 11 to be joined with the yoke 12. A flange 11b is provided on a surface of the bracket 11 which is to be joined with the yoke 12 except for the cutout groove 11a.
Is formed, and the O-ring 14 is disposed outside the base of the flange 11b.

The brush holder 1 is mounted on the bracket 11.
6 is attached by a suitable fixing means such as a set screw.
The brush holder 16 is composed of a brush holder main body 16a and a brush cover 16b, and these members are made of an insulating resin. Brush holder body 1
A brush (not shown) for supplying power to the armature is held at 6a. A notch 16ba is formed in the brush cover 16b so as not to interfere with the grommet 13.
The fitting groove 16 which opens upward in three directions except the notch 16ba
bb is formed (see FIG. 4).

A spacer 18 is provided between the brush holder 16 and the magnet 17 attached to the inner periphery of the yoke 12 to keep the gap between the brush holder 16 and the yoke 12 at a predetermined value. The spacer 18 is formed in a substantially ring shape as a whole, and a wide projection 18a and three fitting projections 18b are formed at a lower portion thereof at intervals of 90 degrees in the circumferential direction. When the spacer 18 is set in a normal state, the wide projection 18a is fitted into the notch 16ba of the brush holder 16, and the fitting projection 18b is fitted into the fitting groove 16bb of the brush holder 16.

The wide projection 18a of the spacer 18 is provided with a step 18aa at the middle in the height direction, and a thin portion 18ab having a small thickness is formed below the step 18aa. Thin part 18a
When the spacer 18 is set in a normal state, the spacer b contacts the inner end surface of the grommet 13 and functions as a wall for preventing the grommet 13 from falling inward. The outer end of the thin portion 18ab is cut off diagonally to form a tapered portion 18ac. Four projections 18c are provided on the upper portion of the spacer 18 at positions corresponding to the wide projections 18a and the fitting projections 18b, and these projections 18c are fitted between the magnets 16, respectively.

Next, the operation of the electric motor seal structure having the above-described structure will be described. The grommet 13 integrally assembled with the O-ring 14 is inserted into the bracket 11 and set at a proper position. Specifically, the grommet 13 is inserted into the notch groove 11a of the bracket 11 and
The ring 14 is arranged outside the base of the flange 11 b of the bracket 11. Next, the brush holder 16 having a brush (not shown) set at a predetermined position is fixed to the bracket 11 by fixing means such as screws. The bracket 11
First, the brush holder 16 may be assembled, and then the grommet 13 integrally fitted with the O-ring 14 may be inserted and set into the bracket 11.

Next, the spacer 18 is attached to the yoke 12 such that the upper projection 18c is located between the magnets 17, and the yoke 12 to which the spacer 18 is attached is attached.
Is fixed to the bracket 11 by an appropriate fixing means such as a screw. At this time, the wide projection 18a and the fitting projection 18b of the spacer 18 are respectively
6ba and the fitting groove 16bb.

Here, the yoke 12 is strongly pressed against the bracket 11 by a fixing means such as a screw. As a result, the inclined portion 12c of the yoke 12 strongly pushes the O-ring 14 and the upper step 13b of the grommet 13 obliquely downward. Push it towards you. Then, the upper step 13b of the grommet 13 tries to fall inward, but the grommet 13 itself has an upper inner end, which is the rear surface, of the thin portion 18a of the projection 18a of the spacer 18.
Because it is supported by b, it never falls inward. As a result, the upper end 13b of the grommet 13 is formed by the inclined portion 12a of the yoke 12 and the protrusion 18a of the spacer 18.
Between the grommet 13 and the yoke 12 is ensured.

The thin portion 18a of the projection 18a forming a wall for preventing the grommet 13 from falling inward
Since b is formed integrally with the spacer 18, the number of components can be reduced and the cost can be reduced without difficulty compared to the case where the projection 18a is separately formed separately.
In addition, the spacer 18 has an upper projection 18c formed of the magnet 1.
7 and the lower projections 18a, 18
b is fitted into the fitting groove 16bb or the like of the brush holder 16,
As a result, highly accurate positioning is performed, and as a result, the thin portion 18ab of the projection 18a serving as a wall for preventing the grommet 13 from falling inward is also accurately positioned.

Since a plurality of vertical ribs 13c are formed on the inner end surface of the grommet 13, these vertical ribs 13c
Accordingly, the grommet 13 can be provided with high rigidity, and the inward fall of the grommet 13 can be more effectively prevented. In addition, the plurality of vertical ribs 13
By absorbing the dimensional variation caused by the assembling and reducing the contact surface, press-fitting can be reduced when the yoke 12 to which the spacers 18 are assembled into the bracket 11, thereby improving the assemblability. Can be achieved.

Further, a tapered portion 18ac is formed at the outer tip of the thin portion 18ab of the projection 18a constituting a wall for preventing the grommet 13 from falling inward, and the tapered portion 18ac is formed on the inner end surface of the grommet 13. Since the thin portion 18ab comes into contact immediately, the penetration of the thin portion 18ab is assisted, so that the assemblability of the yoke 12 and the like can be further improved.

The above-described embodiment is merely an example for describing the invention, and the design can be changed as appropriate without departing from the gist of the invention. Regarding the connection shape between the grommet 13 and the O-ring 14, for example, as shown in FIG. 5A, the upper step portion 13b of the grommet 13 is replaced with the inclined portion 12 of the yoke 12 as shown in FIG.
Even if it has the inclined portion 20 corresponding to c, and as shown in FIG. 2B, the upper portion 21 is formed in a semicircular cross section so as to follow the O-ring 14, As shown in FIG. 4C, the yoke 12 may have a shape having a projection 22 having a circular cross section projecting toward the inclined portion 12a.

[0026]

As described above, according to the present invention, the grommet is provided with a wall for preventing the grommet from falling inward at a position facing the inner end face of the grommet as described above. If pressed, the grommet will not fall inward and will come into strong contact with the yoke while the back is supported by the wall, ensuring a good seal between the grommet and the yoke, which has been difficult to obtain conventionally. It was decided to be. As a result, good sealing performance between the grommet and the yoke was secured. Further, if the wall is interposed between the brush holder attached to the bracket and the magnet attached to the inner periphery of the yoke and is integrally attached to a spacer that keeps a predetermined distance between the two, the wall is separately provided. The number of parts and cost can be reduced compared to the case of providing
Further, since the spacer is originally positioned, the wall can be positioned at a regular position. Also, by forming a vertical rib protruding from the inner end surface of the grommet in a direction perpendicular to the mating surface of the bracket and the yoke, the grommet can be provided with strong rigidity, thereby effectively preventing the grommet from falling down. Can be done,
The yoke can be easily assembled.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a seal structure of an electric motor according to the present invention.

FIG. 2 is an exploded perspective view showing the seal structure.

FIG. 3 is a perspective view showing an inner end surface of a grommet.

FIG. 4 is a sectional view of a seal structure of the electric motor.

FIG. 5 is a sectional view showing various shapes of an upper portion of an inner end surface of the grommet.

FIG. 6 is a perspective view showing a seal structure of a conventional electric motor.

FIG. 7A is a plan view of a grommet with an O-ring used in a seal structure of the electric motor, and FIG. 7B is a sectional view of the grommet.

FIG. 8 is a sectional view showing a seal structure of the electric motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Bracket 11a ... Notch groove 12 ... Yoke 12c ... Inclined part 13 ... Grommet 13a ... Protrusion 13b ... Upper step 13c ... Vertical rib 14 ... O-ring 15 ... Lead wire 16 ... Brush holder 16a ... Brush holder body 16b ... Brush cover 17 Magnet 18 Spacer 18a Projection 18ab Thin part (wall) 18ac Data part 18b Fitting projection 18c Projection

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02G 3/22 H02K 5/10 Z H02K 5/10 F16L 5/02 A F-term (Reference) 3J040 AA17 BA01 BA10 EA16 HA09 HA11 HA30 5G363 AA01 BA01 CA15 CB08 5H605 AA02 AA03 BB05 CC02 CC03 CC06 DD05 DD16 DD32 DD36 EA15 EC01 EC02 EC04

Claims (3)

[Claims] 1. A grommet for leading a lead wire is interposed on a mating surface of a bracket and a yoke, and the grommet has an O grommet.
In a seal structure of an electric motor in which a ring is formed integrally and the O-ring is sandwiched between mating surfaces of a bracket and a yoke to seal between the two, a position facing the inner end surface of the grommet is provided inside the grommet. A seal structure for an electric motor, wherein a wall is provided to prevent the electric motor from falling down. 2. The wall is interposed between a brush holder attached to a bracket and a magnet attached to an inner periphery of a yoke, and is integrally attached to a spacer that keeps a predetermined interval between the two. The seal structure for an electric motor according to claim 1, wherein: 3. The electric motor according to claim 1, wherein a vertical rib is formed on an inner end surface of the grommet so as to extend and protrude in a direction orthogonal to a mating surface of the bracket and the yoke. Motor seal structure.