GB2041453A

GB2041453A - Starter for an internal combustion engine

Info

Publication number: GB2041453A
Application number: GB8003895A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1979-02-07
Filing date: 1980-02-06
Publication date: 1980-09-10
Also published as: FR2448642A1; ES488298A0; GB2041453B; ES8106354A1; IT8019733A0; IT1141173B; DE2904495A1; JPS55107066A

Abstract

The starter includes an intermediate transmission (18,19) interposed between a drive shaft (4) of a starter motor (1) and a transmission shaft (21) on which a meshing drive (34,37) having a starting pinion (39), is movably arranged. The intermediate transmission (18,19) is accommodated in the housing of the starter motor (1) and is sealed by an intermediate plate (8) from the drive bearing structure (10) accommodating the meshing drive, and is also sealed relative to the starter motor (1) by a covering cap (27) fitted on the intermediate plate (8) which retains grease packed around the intermediate transmission (18,19) and also reduces noise of operation. <IMAGE>

Description

SPECIFICATION Starter for an internal combustion engine The invention relates to a starter for an inter nal combustion engine.

Starters for internal combustion engines are known comprising, a starter motor whose drive shaft is operatively connected to a trans mission shaft by way of an intermediate trans mission, and a starter pinion which is arranged on the transmission shaft so as to be rotatable and longitudinally movable and which is likewise operatively connected to the transmission shaft by way of an overrunning clutch and a driver mounted on a coarse screw-threaded portion of the transmission shaft.

In a starter of this kind, the intermediate transmission is accommodated in the drive bearing directly beyond a meshing drive. The intermediate transmission is greased in order to minimise wear on the gear wheels and to damp the meshing sound. However, in the known starter, the grease is flung from the intermediate transmission during the starting operation and then enters the meshing drive in an undesirable manner. Thus, the wear on the gear wheels is relatively large, and the meshing sound of the gear wheels is entirely undamped.

There is provided by the present invention a starter for an internal combustion engine, having a starter motor whose drive shaft is operatively connected to a transmission shaft by way of an intermediate transmission, and having a starter pinion which is arranged on the transmission shaft so as to be rotatable and longitudinally movable and which is likewise operatively connected to the transmission shaft by way of an overrunning clutch and a driver mounted on a coarse screw-threaded portion of the transmission shaft, wherein the transmission shaft extending through a drive bearing has one end rotatably arranged in a second bore in an intermediate bearing in a first bore of which is rotatably journalled that end of the drive shaft which is nearest to the starter pinion, and the intermediate transmission is accommodated in the closed starter motor and is sealed relative thereto by means of a covering cap.

In contrast to the known starter, the starter, in accordance with the invention, has the advantage that, by virtue of the arrangement of the intermediate transmission in the sealed starter motor, relative to which the intermediate transmission is in turn sealed by a covering cap, the grease which reduces wear on the gear wheels, and which damps the sounds caused by the gear wheels, can no longer be flung or centrifuged from the intermediate transmission.

Advantageous developments of the starter of the invention are possible. Thus reception means for the covering cap on the intermediate bearing, and means for sealing the cover ing cap relative to the drive shaft, are particularly advantageous, and it is also particularly advantageous to manufacture the covering cap from sound-proofing plastics material.

One embodiment of the invention is illustrated in the drawing the sole Figure of which is a longitudinal section through the starter of the embodiment.

The starter has a starter motor 1 having a housing 2 in which an excitation winding 3 is secured. A drive shaft 4 carries an armature 5 and a commutator 6. The end of the drive shaft 4 nearest to the commutator is rotatably journalled in a bearing cover 7, and its other end is rotatably journalled in an intermediate bearing 8. The bearing cover 7 and the intermediate bearing 8 are secured to respective end faces of the housing 2 by means of draw rods 9. A drive bearing 10 is screwed to the other side of the intermediate bearing 8 by means of screws 11. A solenoid relay 1 3 is secured to the drive bearing 10 and parallel to the intermediate bearing 8 by means of screws 1 4 with a sealing member 1 2 interposed therebetween.

The intermediate bearing 8 incorporates a first bearing bore 1 5 which accommodates a bearing 16 in which an end portion 1 7 of the drive shaft 4 is rotatably received. A portion having splines 1 8 is contiguous with the end portion 1 7. The splined portion 18 meshes with an external gear wheel 1 9. The gear wheel 1 9 is secured on an end 20, extending through the intermediate bearing 8, of a transmission shaft 21. The transmission shaft 21 extends through a bearing 22 which is fitted in a second bearing bore 23 of the intermediate bearing 8. An edge 24 of the intermediate bearing 8 abuts against the housing 2 of the starter motor 1.The edge 24 extends beyond the portion 1 8 of the drive shaft 4 and that end 20 of the transmission shaft 21 which carries the gear wheel 19, and thus forms a space 25 in the starter motor 1 in which the intermediate transmission 18, 1 9 is accommodated. A reception edge 26 is formed on the intermediate bearing 8 in the region of the first bearing bore 1 5. A covering cap 27 of plastics material is fitted to the intermediate bearing 8 in the reception edge 26 and the edge 24 in the region of the second bearing bore 23. The drive shaft A extends through an opening 28 in the enb face of the covering cap 27.The opening 28 is provided with a sealing lip 29 which surrounds the opening 28 and which abuts sealingly against the drive shaft 4 without obstructing the rotary or longitudinal movement thereof.

The transmission shaft 21, extending through the drive bearing 10, has its ends 30 rotatably received in a bearing 31 in an extension 32 of the drive bearing 10.

The transmission shaft 21 has a coarse screw-threaded portion 33 on which a driver 34 is mounted. The driver 34 is integrally connected by way of a flange 35 to an outer raceway 36 of an overrunning clutch 37. An inner raceway 38 is in the form of an extension of a starting pinion 39 arranged on the transmission shaft 21 so as to be rotatable and displaceable. The raceways 36 and 38 enclose spaces 40 accommodating rollers 41 and associated springs (not illustrated). A cover disc 42 seals the spaces 40. A retaining disc 43 abuts against the outer face of the cover disc 42. The parts 36, 38, 41, 42, 43 of the overrunning clutch are held together by means of a housing portion 44.

A stop ring 45 is arranged on the transmission shaft 21 in the vicinity of the bearing extension 32. Between the starting pinion 39 and the stop ring 45, a ring gear 46 of an internal combustion engine to be started extends through a jaw-like opening 47 of the drive bearing 10 into the meshing region of the starting pinion 39.

A meshing spring 48 is mounted on the driver 34 between the flange 35 and a first stop disc 49 which is likewise loosely arranged on the driver 34. A driver disc 50 is arranged between the first stop disc 49 and a second stop disc 51 so as to be axially and radially movable. The second stop disc 51 abuts against a stop ring 52 of the driver 34.

The driver disc 50 is articulated to a bifucated engaging lever 53. The engaging lever 53 is pivotally mounted on a bearing member 54.

The bearing member 54 is fitted in recesses in the driver bearing 1 0.

The free end 55 of the engaging lever 53 extends into a slot 56 in an actuating bar 57 of an armature (not illustrated) of the relay 1 3. A return spring 59 is arranged between the end 55 of the engaging lever 53 and the housing 58 of the engaging relay 13, one end of which spring abuts against a spring bearing 60. The spring bearing 60 is of strip-like construction and also extends through the slot 56 in the actuating bar 57 and its ends, bent at right angles, overlap the abutting end portion of the return spring 59.

The bifurcated end of the engaging lever 53 is provided with an actuating portion 61 on a level with the drive shaft 4. A guide sleeve 62 is fitted in the first bearing bore 1 5 of the intermediate bearing 8. A resilient actuating member 63 of a deceleration brake device is longitudinally movably guided in the guide sleeve 62. The actuating portion 61 of the engaging lever 53 abuts against the actuating member 63 and maintains the actuating member 63 pressed against the end face 64 of the drive shaft 4. During the deceleration phase of the starting operation, the engaging lever 53, 61 urges the drive shaft 4 towards the bearing cover 7 by way of the resilient actuating member 63.The end of the hub, made from insulating material, of the commutator 6 is thereby pressed against the inside of the bearing cover 7, and the commutator thus acts as a deceleration brake for the starter motor 1.

During the starting operation, the grease applied to the splines of portion 1 8 of shaft 4 and the gear wheel 1 9 can no longer be centrifuged by rotation of the intermediate transmission 18, 19, since the covering cap 27 keeps the grease in the immediate vicinity of the intermediate transmission 18, 1 9. By virtue of the fact that it is arranged in the space 25 in the starter motor 1, the intermediate transmission 18, 1 9 is sealed rom the meshing drive in the drive bearing 10, and is sealed relative to the starter motor 1 by the covering cap 27, and is thus accommodated in a noiseless manner. Furthermore, the wear on the permanently greased intermediate transmission 18, 1 9 is reduced, in the same way as the meshing sound of the intermediate transmission 18, 1 9 is reduced by the grease.

Claims

1. A starter for an internal combustion engine, having a starter motor whose drive shaft is operatively connected to a transmission shaft by way of an intermediate transmission, and having a starter pinion which is arranged on the transmission shaft so as to be rotatable and longitudinally movable and which is likewise operatively connected to the transmission shaft by way of an overrunning clutch and a driver mounted on a coarse screw-threaded portion of the transmission shaft, wherein the transmission shaft extending through a drive bearing has one end rotatably arranged in a second bore in an intermediate bearing in a first bore of which is rotatably journalled that end of the drive shaft which is nearest to the starter pinion, and the intermediate transmission is accommodated in the closed starter motor and is sealed relative thereto by means of a covering cap.

2. A starter as claimed in claim 1, wherein the intermediate bearing, secured between the drive bearing and a housing of the starter motor, has an edge which faces the housing and which forms a space for the intermediate transmission.

3. A starter as claimed in claim 1 or 2, wherein the intermediate bearing is provided with a reception edge for the covering cap in the region of the bearing bore for the drive shaft.

4. A starter as claimed in claim 1, 2 or 3, wherein at least portions of the edge of the intermediate bearing are in the form of a reception edge for the covering cap.

5. A starter as claimed in any of the claims 1 to 4, wherein a sealing edge surrounding the drive shaft is formed in the end face of the covering cap.

6. A starter as claimed in any of the claims 1 to 5, wherein the covering cap is made from plastics material.

7. A starter for an internal combustion engine substantially as hereinbefore described with reference to the accompanying drawings.