GB2042089A

GB2042089A - Starter for an internal combustion engine

Info

Publication number: GB2042089A
Application number: GB8003894A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1979-02-07
Filing date: 1980-02-06
Publication date: 1980-09-17
Also published as: DE2904543A1; IT8019735A0; GB2042089B; IT1140533B; ES8106353A1; FR2448641A1; JPS55107065A; ES488297A0

Abstract

An intermediate transmission (18, 19) is interposed between drive shaft (4) of starter motor (1) and shaft (21) on which a roller clutch 26 and a starting pinion (31) is rotatably and displaceably arranged. Engaging lever (46) transmits the pull-in movement of replay (13) to the pinion (31). The engaging lever has an actuating portion (55, 56) which serves to stop the drive motor 1 in a rapid, silent and low-wear manner when the solenoid is de-energised by pressing a member (62) of resilient actuating assembly (59 to 62) against an end face (63) of the drive shaft 4, to axially displace the shaft and press the commutator (6) of the drive motor against the end casing (7) to brake the drive shaft (4) and thus the meshing pinion shaft (21). <IMAGE>

Description

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

Starters for internal combustion engines are known of the kind having a starter motor whose drive shaft is operatively connected to a transmission shaft by way of an intermediate transmission, and a starting piston which is rotatably and longitudinally movably arranged on the transmission shaft and is coupled by way of an overrunning clutch to a driver mounted on a coarse screw-threaded portion of the transmission shaft and carrying a driver device to which is articulated an engaging lever connected to a solenoid relay and retained in its normal position by means of a return spring.

In a starter of this kind, there is provided a deceleration phase braking device in which the return spring acts upon a braking surface on the transmission shaft. However, the braking action achieved is inadequate, so that the deceleration phase of the starter is too long. Furthermore, the known device is too expensive and is too susceptible to wear.

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 interme diatetransmission, and having a starting piston which is rotatably and longitudinally movably arranged on the transmission shaft and is coupled by way of an overrunning clutch to a driver which is mounted on a coarse screw-threaded portion of the transmission shaft and which carries a driver device to which is articulated an engaging lever connected to an engaging relay and retained in its normal position by means of a return spring, wherein the engaging lever is provided with an actuating portion which abuts against a deceleration braking device acting upon an end face of the drive shaft.

In contrast to the known starter, the starter in accordance with the invention has the advantage that, with the same expenditure of force as in the known construction, the deceleration braking device acts directly upon the starter motor drive shaft which rotates several times more rapidly than the transmission shaft, whereby the deceleration phase of the starting operation can be shortened.

A resilient construction of the actuating member of the deceleration braking device is particularly advantageous, whereby relatively large tolerances can also be compensated for, and it is ensured that the meshing gear also assumes its fixed normal position when the starter is in its normal position.

The wear on the actuating member of the deceleration braking device is minimised in a particularly advantageous manner by having the actuating member in the form of a ball which acts concentrically upon one end face of the drive shaft.

An embodiment of the invention is illustrated in the drawing 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 the commutator is rotatably journalled in a bearing cover 7, and the other end of the drive shaft is rotatably journalled in an intermediate bearing 8. The bearing cover 7 and the intermediate bearing 8 are each secured to a respective end face of the housing 2 by means of draw rods 9. A drive bearing 10 is bolted to the other end face of the intermediate bearing 8 by means of bolts 11. A solenoid relay 13 is secured to the drive bearing 10, and parallel to the intermediate bearing 8, by means of bolts 14; a sealing member 12 being interposed between the drive bearing and the relay.

The intermediate bearing 8 incorporates a first bearing bore 15 in which is arranged a bearing 16 in which an end portion 17 of the drive shaft 4 is rotatably journalled. A portion provided with splines 18 is contiguous with the end portion 17 of the drive shaft 4. The splines 18 mesh with an external gear wheel 19. The gear wheel 19 is secured to an end 20 of a transmission shaft 21 which extends from the intermediate bearing 8. The transmission shaft 21 passes through a bearing 22 which is fitted in a second bearing bore 23 of the intermediate bearing 8. The transmission shaft 21 passes through the interior of drive bearing 10 and its other end is rotatably accommodated in a bearing extension 24 of the drive bearing 10.

The transmission shaft 21 has a coarse screwthreaded portion 25 on which a driver 26 is mounted.

The driver 26 is integrally connected by way of a flange 27 to an outer raceway 28 of the roller-type overrunning clutch 29. An inner raceway 30 of the overrunning clutch 29 is rotatably and displaceably arranged on the transmission shaft 21. The inner raceway is in the form of an end portion of a starting pinion 31. Spaces 32 between the raceways 28 and 30 accommodate rollers 33 and associated springs (not shown). The intermediate spaces 32 are sealed by means of a cover disc 34. The parts 28, 30, 34 of the overrunning clutch are held together by means of a housing member 35.

A stop ring 36 is arranged on the transmission shaft 21 in the vicinity of the bearing extension 24.

Between the starting pinion 31, when in its normal or rest position, and the stop ring 36, a ring gear 37 of an internal combustion engine to be started extends through a jaw-like opening 38 of the drive bearing 10 into the meshing region ofthe starting pinion 31.

A meshing spring 39 is mounted on the driver 26.

One end of the spring 39 abuts against a flange 27, and its other end abuts against a first stop disc 40 which is likewise loosely arranged on the driver 26. A driver disc 41 is disposed between the first stop disc 40 and a second stop disc 42 so as to be axially and radially movable. The second stop disc 42 abuts against a stop ring 43 of the driver 26. The driver disc 41 has two pivot pins 44 on each of which is rotatably secured a respective end 45 of a bifurcated engaging lever 46. The engaging lever 46 is pivotally mounted on a support member 47. The support member 47 is fitted in a recess in the drive bearing 10. The free end 48 of the engaging lever 46 extends into a slot 49 in an actuating bar 50 which extends out of the housing 51 of the engaging lever 13 and which is secured to a magnet armature of the relay 13 in a known manner (not illustrated).A return spring 52 is arranged between the end 48 of the engaging lever 46 and the housing 51 of the engaging relay 13, one end of which spring abuts against a spring abutment 53. The spring abutment 53 is of strip-like construction and extends through the slot 49 in the actuating bar 50, and its ends, bent at right angles, overlap an end portion of the return spring 52.

A cover cap 54 is also fitted in the intermediate bearing and seals the intermediate transmission 18, 19 from the electrical part 3, 5 of the starter motor 1.

The bifurcated engaging lever 46 is provided with an actuating portion 55 on a level with the drive shaft 4. The actuating portion 55 has a rounded actuating face 56. A guide sleeve 57 is fitted in the first bearing bore 15 of the intermediate bearing 8. A resilient actuating member of a deceleration braking device, constituted by members 6 and 7, is longitudinally movably guided in the guide sleeve 57. The resilient actuating member comprises a guide cup 59, a compression spring 60, a pressure plate 61 and a steel ball 62. The compression spring 60 abuts against the end wall of the guide cup 59 and against the pressure plate 61. The pressure plate 61 in turn abuts against the ball 62 which is accommodated in a widened portion of the guide cup 59 so as to be rotatable and longitudinally movable.The rim of the guide cup 59 is bent inwardly slightly in order to prevent the ball 62 from dropping out of the guide cup 59. The guide sleeve 57 has two guide portions adapted to the different diameter of the guide cup 59, wherein the transition from the smaller guide portion to the larger guide portion acts as a saftey means to prevent the guide cup 59 from slipping out of the guide sleeve 57.

When the starter is in its normal position illustrated in the drawing, the actuating portion 55 of the engaging lever 46 abuts externally against the bottom of the guide cup 59. The compression spring 60 maintains the ball 62 in abutment against the end face 63 of the drive shaft 4.

In order to start the internal combustion engine, the relay 13 is connected to a source of current in a known manner by closing the starter switch (not illustrated). The actuating bar 50 of the pull-ed-up magnet armature of the engaging relay 13 pivots the engaging lever 46 in a clockwise direction about its pivot point on the bearing member 47. The driver disc 41 is thereby displaced and moves the driver 26, the overrunning clutcb 29 and the starting pinion 31 towards the ring gear 37. When the starting pinion 31 assumes a tooth-to-gap position on the ring gear 37, it can immediately mesh with the ring gear 37, and the starter motor 1 is at the same time connected to the source of current (not illustrated) by way of the relay 13.The drive shaft 4 commences to rotate and, by way of the intermediate transmission 18,19, the transmission shaft 21, the driver 26 and the overrunning clutch 29, fully meshes the starting pinion 31 with the ring gear 37 until it abuts against the stop ring 36. The starter motor 1 then rotates the ring gear 37 by way of the starting pinion 31 and the internal combustion engine starts.

When the internal combustion engine is running, the relay 13 is isolated from the source of current by opening the starter switch. The magnet armature and its magnet bar 50 return to their normal positions and, with the assistance of the return spring 52, pivot the engaging lever 46 in an anticlockwise direction. The starting pinion 31, which is now being rotated more rapidly than the transmission shaft 21 by the ring gear 37, is disengaged from the ring gear 37 by the driver 26 which is being screwed back on the coarse screw-threaded portion 25, and, together with the driver disc 41 and the engaging lever 46 articulated thereto, the starting pinion returns to its normal position illustrated in the drawing.

During pivoting of the engaging lever 46 in an anti-clockwise direction, the actuating surface 56 of the actuating portion 55 rolls on the end face of the guide cup 59 and urges the guide cup 59 further into the guide sleeve 57. The ball 62, assisted by the force of the compression spring 60, is then pressed against the end face 63 of the drive shaft 4 which moves towards the bearing cover 7, and the end faces of the commutator 6 is pressed against the inside of the bearing cover 7. The hub of insulating material projects beyond the commutator segments at the end face of the commutator 6 and, together with the inside of the bearing cover 7, acts as a deceleration brake. The drive shaft 4, rotating three times more rapidly than the transmission shaft 21 in conformity with the transmission ratio chosen for the intermediate transmission 18, 19, then slows down rapidly in a silent and low-wear manner. Thus, the starter motor 1 stops rapidly after the starting operation has been completed.

Claims

1. Astarterforan 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 starting pinion which is rotatably and longitudinally movably arranged on the transmission shaft and is coupled by way of an overrunning clutch to a driver which is mounted on a coarse screw-threaded portion of the transmission shaft and which carries a driver device to which is articulated an engaging lever connected to an engaging relay and retained in its normal position by means of a return spring, wherein the engaging lever is provided with an actuating portion which abuts against a deceleration braking device acting upon an end face of the drive shaft.

2. A starter as claimed in claim 1, wherein the deceleration braking device has a resilient actuating member which is arranged between the actuating portion of the engaging lever and the end face of the drive shaft.

3. A starter as claimed in claim 1 or 2, wherein the actuating member of the deceleration braking device has a guide cup in which a compression spring and a thrust member are accommodated and which is longitudinally movably guided in a support member.

4. A starter as claimed in claim 3, wherein the thrust member of the actuating member is in the form of a ball which is pressed concentrically against the drive shaft.

5. A starter as claimed in any of the claims 1 to 4, wherein the actuating member of the deceleration braking device is arranged on an intermediate bearing in which one end of the drive shaft and one end of the transmission shaft are rotatably journalled.

6. Astarterforan internal combustion engine, substantially as hereinbefore described with reference to the accompanying drawing.