Starter with band-shaped seal member

Abstract: A starter which assuredly and simply seal an outer circumference of one engagement portion between a housing (4) and a yoke (2) or the other engagement portion between the yoke (2) and an end frame (6) with a band-shaped seal member (1). The banded-shaped seal member (1) covers each engagement portion of the yoke (2), a center plate (3), the housing (4), a brush holder (5), and the end frame (6). The seal member (1) has a clearance (1b) which is placed to correspond to a notched ventilation hole (5a) so that the yoke (2) can be opened in the direction of the starter bottom or the ground.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention: The present invention generally relates to a starter having a band-shaped seal member and, more particularly, it relates to a starter for automobiles. 2. Related Art: In some of the conventional starter, such as disclosed in the JOURNAL OF NIPPONDENSO TECHNICAL DISCLOSURE No. 75-002, a heat contraction tube was used to cover one engagement or coupling portion between a yoke and a housing and the other engagement or coupling portion between the yoke and an end frame as a waterproof seal. However, such a heat contraction tube which is shrinkable and conventionally used is expensive. Furthermore, after the entire starter was assembled, the tube had to be inserted, and heated and contracted in this assembled state. This required increased man-hours to complete the starter. Document DE-A-3422235 discloses an electric motor in accordance with the preamble of claim 1. This known electric motor has a band-shaped seal member wrapped around an outer circumference of a stator core as well as around boundary portions of outer circumferences of end frames arranged adjacent to the end faces thereof. However, when sealing the electric motor in the manner as above described it is likely that ventilation hole portions provided at the stator core or at the boundary portions between the stator core and the end frames are also covered by the band-shaped seal member so that a required ventilation effect is lost. Therefore, the object of the present invention is to be seen in providing a starter having a band-shaped seal member which assures ventilation of the starter. This object is solved by the subject matter of claim 1. Various embodiments thereof are defined in the subclaims. In particular, the starter in accordance with the present invention comprises a band-shaped seal member which is provided and wrapped around an outer circumference of at least one of a first engagement portion between a starter yoke and a housing and a second engagement portion between said starter yoke and an end frame such that a ventilation hole portion of at least one of said starter yoke, said housing and said end frame is maintained open to the outside, thereby keeping the ventilation effect of the ventilation hole. Preferably, the seal member is stuck or adhered to the yoke, and surface treatment of the yoke is not required, thereby reducing costs. The sealing member such as an O-ring used conventionally on the yoke engagement portion can be eliminated, thereby eliminating machining costs and lowering total production cost. Preferably, with one winding of the band-shaped seal member, a clearance at the end portion is made to correspond to a ventilation hole portion of the yoke, housing or end frame, so the ventilation function is attained thereby. Alternatively or more preferably, the band-shaped seal member has a hole portion which corresponds to the ventilation hole portion of the yoke, housing or end frame, so the ventilation function is attained thereby. More preferably, the band-shaped seal member is wound multiple times to overlay, so commercially available seal members can be used. Still more preferably, an outer surface of the band-shaped seal member can be used for a nameplate or caution plate, so the number of parts can be reduced. Still more preferably, by applying the starter to the approximate cylinder portion of a coaxial starter, the band-shaped seal member can be easily mounted thereby improving the mounting efficiency. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: Fig. 1 is a partial cross-sectional view illustrating a starter according to the embodiment of the present invention; Fig. 2 is a partial cross-sectional view illustrating the rear of the starter shown in Fig. 1; Figs. 3A and 3B are a cross-sectional view and a plan view of the ventilation hole of the starter shown in Fig. 1; Fig. 4 is a plan view illustrating the end of the band-shaped adhesive seal member winding of the starter shown in Fig. 1; Fig. 5 is a front view illustrating the other embodiments of the present invention; Fig. 6 is a front view illustrating another embodiment in which the band-shaped adhesive seal member is wound multiple times in the third embodiment of the present invention; Fig. 7 is a plan view illustrating the band-shaped adhesive member in the other embodiment of the present invention; and Fig. 8 is a bottom plan view illustrating the ventilation hole in the other embodiment shown in Fig. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is described in detail hereinunder with reference to the embodiments shown in the accompanying drawings. In Fig. 1 showing the first embodiment, a band-shaped seal member 1 is wound on a starter, which is well known and the description is omitted for brevity, and is made of a material such as polyester, vinyl, paper, cloth, synthetic resin film, metal foil such as aluminum foil, stretchy rubber material or stretchy cloth material. Adhesive is applied on the inner circumference of the seal member 1, and a nameplate la indicating the manufacturer, part numbers, date of manufacture or cautionary item is printed on the outer surface of the seal member 1. The seal member 1 covers a cylindrical field yoke 2 with permanent magnets 8, a disk-like center plate 3, a housing 4 encasing pinion (not illustrated) therein, a disk-like brush holder 5, and an end frame 6 encasing a magnet switch (not illustrated) horiaontally or vertically therein and supporting a battery terminal 9 and a switch terminal 11. Especially, the seal member 1 covers two circular engagement or coupling portions, one between the yoke 2 and the housing 4 and the other between the yoke 2 and the end frame 6. This seal member 1 has a clearance 1b between the circumferential ends of the member 1 so that a notched ventilation hole 5a on the brush holder 5 and yoke 2 can be opened in the direction of the starter bottom as illustrated in Fig. 2 and Figs. 3A and 3B. The material of the band-shaped seal member 1 in this embodiment is most preferably polyester film. The surfaces of the field yoke 2, the center plate 3, the housing 4 and the brush holder 5 can be treated with plating or paint, but as they are covered by the band-shaped seal member 1, this surface treatment can be eliminated. As the end frame 6 is made of resin, the surface does not need to be treated. Even if the end frame 6 is made of metal, the surface does not need to be treated if the frame 6 is covered with the band-shaped seal member 1. A through bolt 7 is placed on a concave portion 2a formed on the yoke 2 and extending radially inwardly between the field yoke 2 and magnets 8, so the amount that it protrudes from the outer circumference of the field yoke 2 is reduced, thereby making the winding of the band-shaped seal member 1 is adhered to the yoke 2 easier. The band-shaped seal member 1 is stuck along a base 7a of the through bolt 7 and a curved convex portion of a screw base 4a of the housing 4. As shown in Fig. 4, the band-shaped seal member 1 can have a multiple portion 1c that covers the joints or coupling portions of the starter where no ventilation holes are formed. Furthermore, as shown in Fig. 5, if the through bolt 7 is placed on the inner diameter side of the field yoke outer diameter, the sticking work and the sticking properties of the band-shaped seal member can be further improved. The band-shaped seal member 1 can also be wound multiple times to overlay as shown in Fig. 6. As shown in Fig. 8, a hole portion 1d can be formed on the band-shaped seal member 1 so that this hole 1d is made to correspond to the notched ventilation hole 5a formed on the yoke 2 shown in Fig. 7, or to the ventilation hole formed on the housing 4 or end frame 6. By using heat insulating material (e.g., aluminum foil, asbestos) for the seal member, the heat to the starter from an engine or exhaust system can be insulated. If a rubber with a large stretching property or a stretchy cloth is used for the band-shaped seal member 1, the contact properties will further increase, and will be especially suitable for the multiple windings shown in Fig. 6. For a coaxial type starter wherein a magnet switch for conducting power to the starter motor is placed in the end frame 6 as shown in Fig. 1, the entire structure of the starter will become generally cylindrical, and the band-shaped seal member 1 can be easily mounted on the outer circumference of the starter because of no parts mounted on the yoke, etc. As shown in Fig. 2, the seal member 1 in the above embodiment covers the outer circumference of the starter by approximately 360 degrees. However, the coupling portion can be covered in the range A that is at least 180 degrees so that the upper half of the starter is covered when mounted on the engine. In an inertia jump-in type starter where the yoke 2 and end the frame 6 are integrally formed, the seal can be made just between the outer circumference of the coupling between the yoke 2 and the housing 4 with the band-shaped seal member 1. The explanation of the general operation of the starter will be omitted for brevity but, instead, the seal effect in this invention will be explained. By sealing the field yoke 2, outer circumference of the engagement or coupling portion of the yoke 2 and center plate 3, outer circumference of the engagement or coupling portion of the center plate 3 and housing 4, outer circumference of the engagement or coupling portion of the yoke 2 and brush holder 5, and outer circumference of the engagement or coupling portion of the brush holder 5 and motor cover 6 using the abovementioned method, the outer circumference of the starter motor is assuredly sealed easily. Furthermore, the battery terminal 9 of the end frame 6 is also used as a seal by mold fixing. The space between the switch terminal 11 and the motor cover 6 is sealed by seal 10. As shown in Fig. 2, with the clearance 1b being placed on the ventilation hole 5a which is opened in the direction of the starter bottom or ground, the ventilation effect of the ventilation hole 5a is not lost.

Claims: A starter comprising: a yoke (2) having magnetic pole means (8) arranged at an inside circumference thereof; at least one of housing (4) engaged with one end of said yoke (2) and an end frame (6) engaged with the other end of said yoke (2); and a band-shaped seal member (1) attached to seal an outer circumference of at least one of a first engagement portion between said yoke (2) and said housing (4) and a second engagement portion between said yoke (2) and said end frame (6); characterized in that at least one of said yoke (2), said housing (4) and said end frame (6) has a ventilation hole portion (5a) communicating between an inside and an outside thereof; and in that said band-shaped seal member (1) is provided and wrapped so as to permit continued communication between the inside and the outside through the ventilation hole portion (5a). The starter according to claim 1, wherein said band-shaped seal member (1) includes an adhesive material. The starter according to claim 1 or 2, wherein a clearance (1b) is formed between circumferential ends of said band-shaped seal member (1), and wherein said clearance (1b) is placed to correspond to said ventilation hole portion (5a) of at least one of said yoke (2), said housing (4) and said end frame (6). The starter according to claim 1 or 2, wherein said band-shaped seal member (1) has a hole portion (1d), and wherein said hole portion (1d) is placed to correspond to said ventilation hole portion (5a) of at least one of said yoke (2), said housing (4) and said end frame (6). The starter according to one of claims 1 to 4, wherein said band-shaped seal member (1) is inclined in the axial line direction, multiply overlaid, and wound on said outer circumference (Fig. 6). The starter according to one of claims 1 to 5, wherein said seal member (1) includes at least one of a sound-absorbing material and an insulating material. The starter according to one of claims 1 to 6, wherein said band-shaped seal member (1) is also used for at least one of a nameplate and a caution plate (1a). The starter according to one of claims 1 to 7, wherein said end frame (6) encases therein a magnet switch. The starter according to one of claims 1 to 8, wherein the band-shaped seal member (1) is wrapped so as to cover an entire outer surface of said yoke (2). The starter according to one of claims 1 to 9, wherein said ventilation hole portion (5a) is formed on a bottom portion of said housing (4), said end frame (6) and said yoke (2). The starter according to one of claims 1 to 10, wherein said yoke (2) has a concave portion (2a) for receiving a through bolt (7) thereon, and wherein said band-shaped seal member (1) is wrapped so as to overlie said bolt (7). The starter according to claim 11, wherein said band-shaped seal member (1) is spirally wound so that side edges thereof overlap.

Inventors: HAYASHI NOBUYUKI, ICHIKAWA HIDEKI, OHMI MASANORI, SHIGA TSUTOMU, HAYASHI, NOBUYUKI , ICHIKAWA, HIDEKI, OHMI, MASANORI, SHIGA, TSUTOMU
Applicants: DENSO CORP, DENSO CORPORATION
Application year: 1995
Main classification: F02N11
IPC codes: H02K5, F02N11