GB2121106A

GB2121106A - An ignition distributor for combustion engines

Info

Publication number: GB2121106A
Application number: GB08309224A
Authority: GB
Inventors: Jurgen Assenheimer; Hartmut G Brammer; Friedrich Jaki; Rolf Rink
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1982-05-03
Filing date: 1983-04-05
Publication date: 1983-12-14
Also published as: AU1394483A; FR2526236B1; GB2121106B; DE3216469C2; ES8402679A1; DE3216469A1; AU549831B2; ES522007A0; MX160785A; GB8309224D0; FR2526236A1; BR8300304A

Abstract

A corrugated spring washer (36) is positioned in an annular groove (15) in a housing (10) and biasses the distributor shaft (20) in one direction by acting on a stop washer (34) thereby forming an axial clearance (37). Movement of the shaft in the opposite direction is limited by the abutment of the stop washer (34) against the end surface (14) of the housing (10). In that case, the maximum compressibility of the corrugated washer (36) is not exceeded so that overloading of or damage to the corrugated washer (36) is prevented even with large axial oscillations of the cam shaft cooperating with the shaft (20). <IMAGE>

Description

SPECIFICATION An ignition distributor for combustion engines State of the Art The invention originates from an ignition distributor for combustion engines according to the preamble to the main claim. With known ignition distributors of that kind, the spring element is a plate washer introduced with pretension between the housing and a pinion on the shaft. When forcing the plate washer through 'towards the block', that is to say during a permanent displacement of the shaft into its inner axial position (axial oscillation), damage to or overloading of the plate washer is not to be excluded. However, this would interfere with the proper functioning of the ignition distributor.

Advantages of the Invention With the ignition distributor for combustion engines according to the invention, the problem demonstrated in the prior art is solved by simple means. The invention is based on the concept of separating the function of the axial play of the shaft from the maximum spring deflection of the spring element.

Advantageous further developments of the invention are described in the sub claims. With the modification of the ignition distributor according to claim 2, it is possible to retain the same constructional length as with ignition distributors without a spring element; in that way, it is possible to change over the combustion engine from an ignition distributor without a spring element to one with a spring element. With the modification of the ignition distributor according to claim 3, rotation of the stop washer is definitely prevented. With claim 6, the axial clearance (longitudinal play) on the shaft may be calculated and established in accordance with normal manufacturing methods.

Drawing An embodiment of the invention is illustrated in the drawing and is explained in detail in the description of the Figures. The single Figure shows a partial axial section through an ignition distributor but not to scale.

Description of the Embodiment An ignition distributor for combustion engines has a pot-like housing 10 comprising a base 11 and a bearing eye 12 receiving a bearing bush 13.

An annular groove 1 5 of rectangular cross-section formed as a depression is recessed in the end surface 14 of the housing 10. A skirt 1 6 provided with an axially directed open ended slot 17, extends from the base 1 The housing 10 is fixed in a manner not shown in the engine block 18 of the combustion engine and is sealed by an Wring 19.

At its end section 21, a shaft 20 mounted in the bearing bush 13 has an annular coupling half 22 provided with two opposite coupling dogs 23 wherein the coupling half 22 is fixed to the shaft 20 by a cylindrical pin 24 and a wire spring 25 secures the cylindrical pin 24 in its operative position. A support plate 26 of a centrifugal governor (not shown) is forced over the shaft 20.

A slip washer made of wear resistant plastics material is arranged between a first and second stop washer 27, 28.

In a similar manner a stop washer 31 engages the end surface of the coupling half 22 against which are supported a compensating washer 32 and a slip washer 33. A stop washer 34 is located on the washer 33 and has an outwardly extending lug 35 which engages in the slot 1 7 in the housing 10. A spring element 36 formed as a corrugated washer is inserted in the annular groove 1 5 in the housing 10 with a predetermined pretension and presses against the stop washer 34.

In the illustrated position, the spring element 36 urges and holds the shaft 20 in its outer axial position and indeed through the washers 34, 33, 32 and 31 as well as through the coupling half 22 and the cylindrical pin 24 so that an axial clearance (bearing play) 37 is provided. During cooperation of the coupling half 22 with the counter coupling half (not shown) of a cam shaft, their axial oscillations can displace the shaft 20 out of its illustrated outer axial position into its inner axial position which is determined by the engagement of the stop washer 34 acting as a shoulder against the end surface 14 of the housing 10. In this inner axial position of the shaft 20, the maximum compressibility of the spring element 36 is not exceeded, that is to say the maximum spring deflection is not reached.Thus, overloading of the spring element, even during permanent axial oscillations of the shaft 20, is excluded.

Instead of the corrugated washer, the axially acting spring element can be, amount other things, a conical coil spring.

1. An ignition distributor for combustion engines comprising a shaft which is mounted in a housing of the ignition distributor with axial clearance and comprising a spring element which maintains the shaft forced into its outer axial position, characterised in that, a shoulder (34) on the shaft (20) determines the inner axial position of the shaft (20) by engaging the housing (10) and that the spring element (36) is arranged in such a manner that its maximum compressibility is not exceeded at the inner axial position of the shaft (20).

2. A distributor according to claim 1 comprising a coupling half on the end section of the shaft for coupling it in particular to the cam shaft of the combustion engine, characterised in that, a stop washer (34) supported by the coupling half (22) forms the shoulder and that an axial depression (15) receiving the spring element (36) is recessed in the end surface (14) of the housing (10).

3. A distributor according to claim 2, characterised in that, the spring element is formed as a corrugated washer (36) or as a conical coil

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION An ignition distributor for combustion engines State of the Art The invention originates from an ignition distributor for combustion engines according to the preamble to the main claim. With known ignition distributors of that kind, the spring element is a plate washer introduced with pretension between the housing and a pinion on the shaft. When forcing the plate washer through 'towards the block', that is to say during a permanent displacement of the shaft into its inner axial position (axial oscillation), damage to or overloading of the plate washer is not to be excluded. However, this would interfere with the proper functioning of the ignition distributor. Advantages of the Invention With the ignition distributor for combustion engines according to the invention, the problem demonstrated in the prior art is solved by simple means. The invention is based on the concept of separating the function of the axial play of the shaft from the maximum spring deflection of the spring element. Advantageous further developments of the invention are described in the sub claims. With the modification of the ignition distributor according to claim 2, it is possible to retain the same constructional length as with ignition distributors without a spring element; in that way, it is possible to change over the combustion engine from an ignition distributor without a spring element to one with a spring element. With the modification of the ignition distributor according to claim 3, rotation of the stop washer is definitely prevented. With claim 6, the axial clearance (longitudinal play) on the shaft may be calculated and established in accordance with normal manufacturing methods. Drawing An embodiment of the invention is illustrated in the drawing and is explained in detail in the description of the Figures. The single Figure shows a partial axial section through an ignition distributor but not to scale. Description of the Embodiment An ignition distributor for combustion engines has a pot-like housing 10 comprising a base 11 and a bearing eye 12 receiving a bearing bush 13. An annular groove 1 5 of rectangular cross-section formed as a depression is recessed in the end surface 14 of the housing 10. A skirt 1 6 provided with an axially directed open ended slot 17, extends from the base 1 The housing 10 is fixed in a manner not shown in the engine block 18 of the combustion engine and is sealed by an Wring 19. At its end section 21, a shaft 20 mounted in the bearing bush 13 has an annular coupling half 22 provided with two opposite coupling dogs 23 wherein the coupling half 22 is fixed to the shaft 20 by a cylindrical pin 24 and a wire spring 25 secures the cylindrical pin 24 in its operative position. A support plate 26 of a centrifugal governor (not shown) is forced over the shaft 20. A slip washer made of wear resistant plastics material is arranged between a first and second stop washer 27, 28. In a similar manner a stop washer 31 engages the end surface of the coupling half 22 against which are supported a compensating washer 32 and a slip washer 33. A stop washer 34 is located on the washer 33 and has an outwardly extending lug 35 which engages in the slot 1 7 in the housing 10. A spring element 36 formed as a corrugated washer is inserted in the annular groove 1 5 in the housing 10 with a predetermined pretension and presses against the stop washer 34. In the illustrated position, the spring element 36 urges and holds the shaft 20 in its outer axial position and indeed through the washers 34, 33, 32 and 31 as well as through the coupling half 22 and the cylindrical pin 24 so that an axial clearance (bearing play) 37 is provided. During cooperation of the coupling half 22 with the counter coupling half (not shown) of a cam shaft, their axial oscillations can displace the shaft 20 out of its illustrated outer axial position into its inner axial position which is determined by the engagement of the stop washer 34 acting as a shoulder against the end surface 14 of the housing 10. In this inner axial position of the shaft 20, the maximum compressibility of the spring element 36 is not exceeded, that is to say the maximum spring deflection is not reached.Thus, overloading of the spring element, even during permanent axial oscillations of the shaft 20, is excluded. Instead of the corrugated washer, the axially acting spring element can be, amount other things, a conical coil spring. CLAIMS

3. A distributor according to claim 2, characterised in that, the spring element is formed as a corrugated washer (36) or as a conical coil spring and that the depression in the end surface of the housing (1 0) receiving the spring element (36) has the form of an annular groove (15).

4. A distributor according to claim 3, characterised in that, a lug (35) extends outwardly from the stop washer (34) and that an axially directed slot (17), in which the lug (35) on the stop washer (34) engages, is recessed in the housing (10).

5. A distributor according to one of claims 2 to 4, characterised in that, a further stop washer (31) engages the end surface of the coupling half (22) and that a slip washer (33), preferably made of plastics material, is arranged between the two stop washers (31, 34).

6. A distributor according to claim 5, characterised in that, one or more compensating washers (32) are arranged between the stop washer (31) and the slip washer (33).

7. An ignition distributor for combustion engines substantially as herein described with reference to the accompanying drawing.