GB2114827A

GB2114827A - A switching arrangement for starting an internal-combustion engine by means of several electric starting motors

Info

Publication number: GB2114827A
Application number: GB08235484A
Authority: GB
Inventors: Bernd Sieber; Herbert Martin
Original assignee: DRESDEN ELEKTROMOTOREN
Current assignee: DRESDEN ELEKTROMOTOREN
Priority date: 1981-12-28
Filing date: 1982-12-13
Publication date: 1983-08-24
Also published as: DE3241079A1; CS879882A1; CS259004B1; FR2519087A1; SU1339291A1; DD206919A3; HU189621B; GB2114827B

Abstract

The starting motors 5, 25 are connected in parallel and have respective two-stage meshing devices actuated by electromagnets 4, 24, means being provided to ensure that the second starting stage is switched on to energise the motors at full power only after the pinions 6, 26 of all the starting motors 5, 25 have become fully meshed with the I.C. engine. On closing a switch 2 holding windings 4.1, 24.1 or electromagnets 4, 24 and operating windings 3.2, 23.2 of relays 3, 23 are energized. Switches 3.1, 23.1 are thereby closed so that motors 5, 25 are connected in series with pull-in windings 4.2, 24.2 of electromagnets 4, 24 respectively. The electromagnets thus move pinions 6, 26 into mesh with gear ring 10 and urge switches 4.3, 24.3 to a closed position, power 9, 29 preventing closure of these switches at this stage. Series connected switches 7, 27 are closed on full meshing of pinions 6, 26 respectively with ring 10 so that operating windings 8, 28 are only energised to release power 9, 29 when both pinions 6, 26 are fully meshed. Switches 4.3, 24.3 close on release of power 9, 29 to short out pull-in windings 4.2, 24.2 and thus energise motors 5, 25 at full power. Switches 7, 27 may be mechanical limit switches or solid state thyrators. <IMAGE>

Description

SPECIFICATION A switching arrangement for starting an internal-combustion engine by means of several electric starting'motors The invention relates to a switching arrangement for starting an internal-combustion engine by means of several electric starting motors which are connected in parallel and are each provided with a two-stage meshing device which is actuated by an electromagnet.

Starters are equipped with meshing devices for causing the pinion to mesh with the ring gear of the internal-combustion engine. Meshing is effected by utilising the action of the force exerted by an electromagnet. A switching arrangement controls the co-operation between the electromagnet and the starting motor during the meshing process so that the pinion finds, with its teeth, gaps between the teeth of the ring gear of the internal-combustion engine and is axially inserted into the ring gear. If the power of a starting motor is not sufficient for starting the internal-combustion engine, then use is made of several starting motors which act on the ring gear of the internal-combustion engine.

In a first known switching arrangement, a closing switch connects, in a first starting stage, the operating winding of the control relay and the holding winding, which is connected in parallel therewith, of the electromagnet of a starting motor to a power source. During this process, the switch of the control relay connects the series connection of a pull-in winding of the electromagnet and of the starting motor to the power source. The pinion of the starting motor meshes with the ring gear under the action of the axial force exerted by the electromagnet and of the torque exerted by the starting motor. When the end position of the pinion is reached, a switch which is also actuated by the electromagnet, closes and connects the holding winding of the electromagnet of a second starting motor and the operating winding of its control relay to the power source.The switch of the control relay then connects the series connection of a pull-in winding of the electromagnet and of the starting motor to the power source. The second starting motor is also thrown into engagement. When the pinion reaches its end position, a switch on the second starting motor also closes and connects the operating winding a separate starting relay to the power source. The starting relay bridges, with a respective switch, the pull-in winding of each starter so that the starting motors start with their full torque in a second starting stage.

In a second known solution, the control relays are also arranged outside the housings of the starting motors. Once the pinions of the two starting motors are in mesh, the switches linked to the electromagnets of the starting motors and connected in series cause voltage to be applied to the operating windings of a power relay and a starting relay, which are both located outside the starting motors. The switch of the power relay bridges the pull-in winding of one starting motor and the switch of the starting relay bridges the pull-in winding of the other starting motor. By this means, the starting motors start with their full torque.

In other known solutions, it is also always starting relays arranged outside the starting motors which have the function of bridging the pull-in windings or of a compensating resistor (e.g.

DDWP 144091).

What is disadvantageous in all known solutions is the increased expenditure for the external starting relays and the use of special starting motors which, for parallel operation, in most cases differ considerably from the standard design.

Furthermore, the starting relays necessitate a larger constructional space and an additional expenditure of material.

It is the object of the invention to do away with the larger constructional space requirement, the additional expenditure of material for the starting relays and the increased expenditure for the starting motors which differ from the standard design.

The technical problem underlying the invention is to provide a switching arrangement whose switching elements for realising the parallel operation of several starting motors are largely arranged inside the starting motor housings and wherein only a few switching elements differ from the standard design of the starting motors.

According to the invention, this problem is solved by a switching arrangement including a two-stage meshing device, each starting motor thereof having an electromagnet for the axial displacement of the pinion. The electromagnet comprises a holding winding and a pull-in winding. The pull-in winding is connected to one pole of the power source via a switch and is connected in series with the starting motor.

Connected in parallel with the series connection of the switch and the pull-in winding is another spring-loaded switch which is also actuated by the electromagnet and which is prevented from closing by an electromagnetically operated locking pawl. The operating windings of the locking pawls of the parallel-connected starting motors are connected, with respectively one end, to one pole of the power source. The other ends of the operating windings are interlinked and are connected to the other pole of the power source via series connection of switching elements, of which there is one on each starting motor. With the pinions completely meshed, the switching elements experience a change of a physical quantity. This causes the switching elements to be rendered conductive.

During starting, the closing of the switch causes the series connection of the pull-in winding and the starting motor to be applied to the power source. The electromagnet axially displaces the pinion. The compensating resistor of the pull-in winding causes the starting motor to develop a reduced torque so that, due to the rotation of the pinion, the pinion teeth find gaps in the ring gear of the internal-combustion engine and the pinion is thrown into mesh. When the pinion reaches its end position, the associated switching element is rendered conductive.Only when all the pinions of the parallel-connected starting motors have reached their end positions is the electric circuit closed by the operating windings and are the locking pawls simultaneously operated so that the switches, which are connected in parallel with the series connection of the pull-in winding and the switch, close under the spring-loading action. By this means, all the starting motors are directly connected to the power source and simultaneously develop their full torque.

In a switching arrangement variant according to the invention, the switching elements are formed by limit switches which close the electric circuit directly by the operating windings of the locking pawls.

In a second switching arrangement variant according to the invention, the switching elements are formed by solid-state thyratrons.

The invention will hereinafter be explained in more detail with the aid of an exemplified embodiment.

The accompanying drawings show a switching arrangement for two parallel-connected starting motors. A closing switch 2 links the parallelconnected operating windings 3.2; 23.2 of the control relays 3; 23 and the holding windings 4.1: 24.1 of the electromagnets 4; 24 to one pole of the power source 1. A series connection, formed by the pull-in winding 4.2 of the electromagnet 4, the switch 3.1 of the control relay 3 and the first starting motor 5, is connected to the power source. Connected in parallel therewith is a series connection, formed by the pull-in winding 24.2 of the electromagnet 24, the switch 23.1 of the control relay 23 and the second starting motor 25, to the power source. Connected in parallel with the series connections formed by the pull-in windings 4.2; 24.2 and the switches 3.1; 23.1 are the switches 4.3; 24.3 of the electromagnets 4; 24.The switches 4.3; 24.3 are movable towards the electromagnets 4; 24 in a spring-loaded manner and are locked by the locking pawls 9; 29 operated by the operating windings 8; 28. The operating windings 8; 28 are connected, with respectively one end, to one pole of the power source 1. The other ends thereof are interlinked and are connected, in a series connection with theswitching elements 7; 27, to the other pole of the power source. The switching elements 7; 27 are so arranged that, with the pinions 6; 26 fully meshed, the switching elements 7; 27 experience in the end positions A a change of the physical quantity and, as a result, close the electric circuit by the operating windings 8; 28.

For initiating the starting process, the closing switch 2 is closed. The current caused to flow from the power source 1 via the closing switch 2, the operating windings 3.2; 23.2 of the control relays 3; 23, the holding windings 4.1; 24.1 to the power source causes the control relays 3; 23 to pull up. By this means, the switches 3.1; 23.1 close and current flows from the power source 1 through the pull-in windings 4.2; 24.2 and the starting motors 5; 25. The action of the force exerted by the electromagnets 4; 24 and the action of the torque of the starting motors 5; 25 cause the pinions 6; 26 to mesch with the ring gear 10. Owing to the locking action of the locking pawls 9; 29, the switches 4.3; 24.3 cannot close.

When the pinions 6; 26 have reached their end positions A, the switching elements 7; 27 close the electric circuit from the power source 1 by the operating windings 8; 28. This causes the locking pawls 9; 29 to release the switches 4.3; 24.3. The switches 4.3; 24.3 close on account of the action of the force exerted by pre-tensioned springs not shown and bridge the series connections of the pull-in windings 4.2; 24.2 and the switches 3.1; 23.1. The starting motors 5; 25 now simultaneously start the internal-combustion engine with the full torque.

Claims

1. A switching arrangement for starting an internal-combustion engine by means of several electric starting motors, more especially provided with a two-stage meshing device actuated by an electromagnet, and wherein each starting motor (5, 25) comprises a meshing device with an electromagnet (4; 24), a holding winding (4.1; 24.1) and with a pull-in winding (4.2; 24.2), which is linked to one pole of the power source via a switch (3.1; 23.1) and is connected upstream of the starting motor (5; 25), and which a springloaded switch (4.3; 24.3) which is connected in parallel with the series connection of the pull-in winding (4.2; 24.2) and the switch (3.1; 23.1) and which is actuated by the electromagnet (4; 24), characterised in that a locking pawl (9; 29), which is operated by an operating winding (8; 28), prevents the switch (4.3; 24.3) from closing, and in that the operating windings (8; 28) of the locking pawls (9; 29) of the parallel-connected starting motors (5; 25) are connected, with respectively one end, to one pole of the power source (1) and the other ends are interlinked and are connected, in series with the switching elements (7; 27) which, with the pinions (6; 26) fully meshed, experience a change of a physical quantity and are thus rendered conductive, to the other pole of the power source (1).

2. A switching arrangement as claimed in Claim 1, characterised in that the switching elements (7; 27) are formed by limit switches.

3. A switching arrangement as claimed in Claim 1, characterised in that the switching elements (7; 27) are formed by solid-state thyratrons.

4. A switching arrangement substantially as described with reference to the accompanying drawing.