GB2159893A

GB2159893A - A mounting arrangement for a sleeve bearing

Info

Publication number: GB2159893A
Application number: GB08517946A
Authority: GB
Inventors: Toshinori Tanaka; Akira Morishita
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 1981-12-22
Filing date: 1985-07-16
Publication date: 1985-12-11
Also published as: GB2113319A; GB8517946D0; FR2518654B1; FR2518654A1; JPS5896123U; GB2113319B; GB2159893B

Abstract

A sleeve bearing (30) for an engine starter motor is fitted to a frame (24) and is held in position by projections (27) on respective opposite axial ends of a frame (24) made of thermoplastic resin material, the projections (27) engaging projecting and recessed engaging portions (31) at opposite ends of the sleeve bearing. <IMAGE>

Description

1

SPECIFICATION

Bearing with improved stability The present invention relates to a bearing means, for example, in a starter motor for an engine.

Motors of the type shown in Fig. 1 for starting engines are well known in the prior art. In Fig. 1, 1 is a D.C. motor. There is a front bracket 6 fixed at the forward end of a cylindrical yoke 2 of this motor 1.

An internal gear3 of deceleration mechanism 7, an intermediate bracket 4 and a rubber ring 5 are fitted at the inner peripheral surface of this bracket:6. A rotary shaft 9 is fitted in an armature 8 of the D.C.

motor 1. A spur gear 10 is engaged with a planetary gear 11. The planetary gear 11 is rotatably supported on a support pin 13 via a bearing 12 and is also engaged with the internal gear 3. The above mentioned support pin 13 is fixed to a flange 14, which is integrally formed with an output rotary shaft 15. A sleeve bearing 16 is fitted at the inner peripheral surface of the intermediate bracket 4, and the sleeve bearing 16 supports the output rotary shaft 15.

A sleeve bearing 17 is fitted in a recess 18 which is formed in the inner peripheral surface atthe rearward end of the output rotary shaft 15. The sleeve bearing 17 supports the forward end of the rotary shaft 9 of the armature. A steel ball 19 is interposed between the forward end of the rotary shaft 9 of the armature and the rearward end of the output rotary shaft 15 which is arranged on the extension of the axis of this rotary shaft 9. The function of the steel ball is to impart and absorb the thrust loading of both rotary shafts 9, and 15. In Fig.

1, 20, 21 and 22 are thrust washers, and 23 is a helical spline which is formed on the outer peripheral surface of the output rotary shaft 15 and to which an overrun clutch (not shown) is spline coupled.

The operation of the above-described motorwill 105 now be described. An electric current energizes the armature 8 thereby resulting in rotation of rotary shaft 9. This rotational power is transmitted from the rotary shaft 9 of the armature to the flange 14 via the spur gear 10, the planetary gear 11 and the support pin 13, so that the rotational speed of the armature 8 is decelerated by the planetary gear mechanism 7 and transmitted to the output rotary shaft 15.

If the intermediate bracket 4 is made of synthetic resin material, in order to lower the cost and reduce the weight of the motor, then a problem results in that the sleeve bearing 16 which is fitted to the intermediate bracket 4 becomes mispositioned due to stress.

The object of the invention is to provide a bearing device for a starter motor which has the advantages of the use of synthetic resin materials, in cost and lightweight but which has strength sufficient to support the bearing.

According to the present invention there is provided a bearing device comprising a frame made of thermoplastic resin material and having at least one engaging portion on its inner peripheral surface; and a bearing elementfitted to said frame GB 2 159 893 A 1, and having at least one end in engagement with said engaging portion.

A sleeve bearing may be fitted to the f rame, which may be an intermediate bracket made of thermoplastic synthetic resin material. Said at least one engaging portion may be formed with a projection by deformation when the frame is heated at its inner peripheral surface. At least one end surface of the bearing is adapted to come into engagement with the engaging portion so as to absorb the thrust loading of the bearing. This maintains the bearing in proper position, solving the above mentioned problem while stabilizing the mounting strength of the bearing over the long term.

The invention will now be described by way of example with reference to and as shown in the accompanying drawings in which:

Fig 1 is an upper half side view in cross section showing the forward portion of an engine starter motor which is provided with conventional bearing means.

Fig. 2 is an upper half side view in the cross section showing a bearing means constructed in accordance with a first embodiment of the present invention; Fig. 3 is a cross sectional view taken along 111-111 line in Fig. 2; and Fig. 4 is a perspective view showing one end portion of a sleeve bearing constructed in accordance with a second embodiment of the present invention.

In the drawings, the same reference numerals denote the same elements.

A first embodiment of the present invention will be explained with reference to Fig. 2 and Fig. 3, and a second embodiment will be explained with reference to Fig. 4. In Fig. 2 and Fig. 3, 24 is an intermediate bracket which is manufactured in accordance with well known mold processing methods with nylon as the material for the main component. A sleeve bearing 26 is fitted at the inner peripheral surface 25 of bracket 24. Both the ends of the bracket 24 are caulked in accordance with well known thermal caulking processing methods and engaging portions 27, 27 project from the inner peripheral surface 25, to engage both end surfaces of the sleeve bearing 26. In addition, a plurality of grooves 28 are formed circumferentially in the outer peripheral surface of the sleeve bearing 26. Projections 29 which are provided on the inner peripheral surface of the intermediate bracket 24 engage the grooves 28 so as to provide a mechanism to prevent relative rotation between the sleeve bearing 26 and the intermediate bracket 24.

The above-mentioned intermediate bracket 24 and sleeve bearing 26 are assembled into the starter motor in such a way that the intermediate bracket 4 and the sleeve bearing 16 which are shown in Fig. 1 are respectively replaced. Because all of the parts in this embodiment, other than the intermediate bracket and the sleeve bearing, are the same as those in Fig. 1, they are not shown and the explanation of their operation has been omitted.

A starter motor with the bearing means as 2 GB 2 159 893 A 2 described above, is able, over the long term, to absorb the loading in both the axial thrust direction and the radial direction, which are applied to the sleeve bearing 26. This is achieved by the engagement of the grooves 28 of the sleeve bearing 26 and the projections 29 of the intermediate bracket 24 and by employing a simple means to make the engaging portions 27, 27 project from the inner peripheral surface of the intermediate bracket 24 when heated.

A second embodiment allows the intermediate bracket to absorb the radial loading of the sleeve bearing with the end surface of the sleeve bearing by forming radially projected and recessed engaging portions 31 atone or both the end 55 surfaces of the sleeve bearing 30, as shown in Fig. 4.

The sleeve bearing 30 is mounted to the intermediate bracket 24, as shown in Fig. 2, and the projecting and recessed engaging portions 31 at the engagings portions 27, which are formed on the intermediate bracket 24 in accordance with the thermal caulking method. In this case, there is no necessity to provide the projections or recesses on the outer peripheral surface of the sleeve bearing, and the sleeve bearing may therefore be cylindrical.

This is advantageous in that the intermediate bracket will be easy to manufacture.

Although the embodiments have been explained with respect to the case in which the sleeve bearing is mounted to an intermediate bracket in a starter motor, the bearing in this invention may be another type of bearing, for example, a ball bearing. In addition, the present invention is widely applicable in cases where the bearing is mounted to a general frame in other instruments or devices.

The bearing means constructed in accordance with the present invention as explained hereinabove, there are provided engaging portions which project, by deformation during a heating step in the fabrication process, atone location or a 80 plurality of locations on the inner peripheral surface of a frame which is made of a thermoplastic synthetic resin material such as nylon. At least one end of the bearing is in engagement with the engaging portion so as to receive the axial thrust loading of the bearing. Ittherefore becomes possible to preventthe axial displacement of the bearing, overthe long term, despite the factthat the frame is lightand simply constructed. Afurther advantage of the present invention is that it is possible to provide the bearing means with a high reliability at a low cost.

Claims

1. A bearing shaft which rotatably supports an output rotary shaft, said output rotary shaft having a flange for fixing a support pin of a planetary gear, said bearing device comprising: a frame made of thermoplastic resin material and concentrically disposed around said output rotary shaft, said frame having engaging portions on an axial end thereof, and a bearing element interposed between said output rotary shaft and said frame and fitted to said frame, said bearing element being formed with projecting and recessed irregularities at its axial end to be engaged with said engaging portions.

2. A bearing device as claimed in claim 1, wherein said engaging portions are formed by heat deformation during fabrication of said frame.

3. A bearing device as claimed in claim 1 or claim 2 wherein said engaging portions project radially from the axial ends of the inner peripheral surface of the frame.

4. A bearing device as claimed in any one of the preceding claims, wherein the bearing element is a sleeve bearing.

5. A bearing device substantially as hereinbefore described with reference to and as shown in Figures 2 and 4 of the accompanying drawings.

Printed for Her Majesty's Stationery Office by Courier Press, Leamington Spa. 1211985. Demand No. 8817443. Published by the Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.