GB2147366A

GB2147366A - I.c. engine starter motor

Info

Publication number: GB2147366A
Application number: GB08421136A
Authority: GB
Inventors: Alfred Bruno Mazzorana
Original assignee: Societe de Paris et du Rhone SA
Current assignee: Societe de Paris et du Rhone SA
Priority date: 1983-09-29
Filing date: 1984-08-20
Publication date: 1985-05-09
Also published as: FR2552824B1; FR2552824A1; DE3433440A1; GB8421136D0

Abstract

A pneumatic, hydraulic or electric motor 1 rotatably drives a pinion 9 which is displaced axially in order to be brought into contact with a crown wheel 10 of the engine. The axial displacement of the pinion 9 is effected by an electromagnetic actuator 13 or an electric rotary actuator (37, Fig. 2) through a pinion 17 rotated by a rack 16 operated by the core 14 of the actuator 13 or rotated directly by the actuator (37) and a pinion 20 driving a rack 11 connected through a freewheel 12 to the pinion 9. The pinions 17, 20 are connected by a toothed belt 25, a chain or rack which is biased by a spring 30 to effect pinion return when the actuator is deenergized. <IMAGE>

Description

SPECIFICATION Starter for an internal combustion engine The present invention concerns a starter, in particular an electric starter, for an internal combustion engine.

In starters designed for internal combustion engines, the electric motor rotatably drives, directly or by the intermediary of a reduction gear, a device called a "launcher" consisting of a pinion which is brought into mesh with a starter crown wheel which is generally situtated on the engine fly wheel. The pinion of the launcher is driven in rotation by the intermediary of a free-wheel driver, and it is movable axially along its drive shaft to be able to come into contact with the crown wheel and separate from this crown wheel after the engine has started.

In positively driven starters this connection is ensured by means of a special clutch device which generally consists of an electromagnetic activator which moves one end of a lever the other end of which is forked and linked to the back of the launcher which may take the form of a pulley. A spring called the "tooth against tooth" must be interposed into the clutch device, for example between the launcher pulley and the body of the free-wheel driver of this launcher in order to enable at all times full movement of the moving core of the electromagnetic activator which, towards the end of its movement also comes to close the electric contacts for setting up the voltage in the starter motor and it is, for this reason also called a "contact".The "tooth against tooth" spring must store up the energy necessary to penetrate the teeth of the launcher pinion in those of the crown wheel, after this pinion has been set in rotation, This type of device gives satisfaction on the whole. However it sill gives rise to certain drawbacks. The forked end of the lever thus entails problems in practice and is sensitive to vibrations, to play existing in the contacts between this lever and the moving core of the electromagnetic activator and similar play between this lever and the launcher. Moreover, each starter requires its own special lever characterised by its length and its lever arms, which are determined by the distance separating the axle of the activator from that of the launcher, by the movement of the moving core of the activator, and by the movement of the launcher.

An object of the present invention is to obviate or mitigate these drawbacks.

According to the present invention there is provided a starter for an internal combustion engine, comprising a motor, for example electric, which rotates a launcher comprising a drive and a pinion suitable to be brought into contact with a starter crown wheel carried by the engine to be started, the launcher being capable of axial displacement along its shaft and having its axial displacement controlled by an activator, a transmission linking the activator to the launcher including a first rotating pinion rotatable by the moving part of the activator, a second rotating pinion on an axle parallel to the axle of the first pinion and coming into contact with a longitudinally toothed part of the launcher, and connection means between the two pin ions.

Preferably the first pinion is in contact with a set of teeth of "rack and pinion" type formed on a shaft fixed to the moving core of an electromagnetic solenoid activator, while the second pinion is in contact with another set of teeth of the "rack-and-pinion" type formed on the body of the drive of the launcher. These teeth, particularly those on the body of the drive of the drive of the launcher which is a rotating member, are formed preferably by alternate grooves and ring shaped ribs enabling the member which bears them to come into contact with the corresponding pinion, regardless of the angle at which this instrument is placed.

The connection means which links the first pinion to the second pinion the axles of which are preferably parallel to each other, may be a notched belt or a chain closed on itself and extending between the two pin ions. Instead of using a connection means which is subject to deformation, the mounting of a straight rigid rack-and-pinion, suitably guided and coming into contact tangentially with the two pinions can also be envisaged.

In all the cases, the classic lever is thus replaced by a transmission without play and far more flexibly adapted to the function of the starter characteristics. Thus, in the case of transmission by a notched belt, it is easy to choose the length of that belt according to the distance between the axles of the activator and the launcher, and the choice of the number of teeth in the two pinions enables all combinations of movements of the activator and the launcher. The suggested device also brings some simplification in the moving gear of the activator and in the structure of the launcher itself, which leads to a saving in the cost price of the starter.

In those cases where the connecting instrument between the two pinions is a connection means which is subject to deformation, such as notched belt or chain closed on itself, the "tooth against tooth" spring is set up, in accordance with a preferable form of production, using a spring linking the two ends of the means such as notched belt or chain, which is stretched between these two ends.

As for the return spring of the launcher in a resting position, it can be produced in the form of a spring stretched between a point of the connection means, such as notched belt, in contact with the two pinions, and a fixed point of the starter.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is an overall view showing a longitudinal section of a starter, shown in a resting position, with an indication in chain lines of the position of a launcher when the starter is in action; Figure 2 is an isometric view showing more particularly, the device for the transmission of movement between the activator and the launcher, with an indication of a possible modification.

Fig. 1 shows a starter for a motor vehicle, consisting of a direct current electric motor 1 with a stator 2 and a rotor 3 borne by a shaft 4 the ends of which are mounted in two bearings 5, 6. The shaft 4 carries adjacent to the first bearing 5 the commutator 7 of the electric motor 1, while on its other side is mounted a launcher 8, rotatably mounted on this shaft 4 but being able to slide the length of this shaft. As a general rule, the launcher 8 consists of a pinion 9, capable of coming into contact with a crown wheel 10 situated on the drive wheel, and with a drive of this pinion consisting of a body 11 and a freewheel 12.

An electromagnetic activator 1 3 is arranged parallel to the electric motor 1. It comprises, in a well known manner, a fixed solenoid in which may be shifted a moving core 14 which, on the one hand, controls the closing of electric contacts by the intermediary of which the electric motor 1 is actuated, and on the other hand, it brings about the axial displacement of the launcher 8.

To that end, in accordance with the present invention, the moving coil 14 of the electromagnetic activator 1 3 is extended in an axial direction by a shaft 1 5 on which is shaped a set of teeth 1 6 of the "rack-and-pinion" type -see also Fig. 2. The teeth 1 6 are provided by alternate grooves and ring shaped ribs, which enable them to behave in the same way at any angle at which the shaft 1 5 is disposed.

A first double pinion 1 7 is mounted to rotate about an axle 1 8 fixed perpendicular to the axis of the activator 13, close to the shaft 1 5. The pinion 1 7 consists of a first section with teeth 1 9 coming into contact with the teeth 1 6 of this shaft 1 5 to produce a transmission of the "pinion to rack-and-pinion" type.

A second double pinion 20 is mounted to rotate about a fixed axle 21 situated parallel to the axle 1 8 of the first pinion 1 7, and situated close to the launcher 8. On the body 11 of the drive of the launcher 8 are shaped grooves and ring shaped ribs which also produce teeth of the "rack-and-pinion" type which behave in the same way at any angle at which the launcher 8 is placed. These teeth come into contact with a first toothed section 22 of the second double pinion 20.

The two double pinions 17, 20 each possess a second section with teeth, 23, 24 respectively, and a notched belt 25 links these two pinions in a loop and winding round the respective sections with teeth 23, 24. A restraining device 26 for the notched belt 25 may be fixed to at least one of the two pinions 17, 20. The notched belt 25 has two ends 27, 28 permanently situated on one of its runs and separated from each other by a relatively slight distance, these two ends 27, 28 being linked to each other by means of a helical spring 29 stretched between them. A second helical spring 30 is stretched between a fastening position 31 situated on the other run of the notched belt 25, and a fixed position 32 situated on the casing 33 of the starter.

This whole transmission device is shown in a resting position in Fig. 1. When the starter is prompted, the moving core 14 is drawn towards the inner part of the solenoid from the activator 1 3. The shaft 1 5 linked to the moving core 14 is displaced from the left to the right, and its teeth of the rack-and-pinion type 1 6 bring into rotation the first pinion 1 7 about its axle 1 8 in the direction shown by the arrow 34. By the intermediary of the notched belt 25, which has been displaced in the direction of the arrow 35, the first pinion 1 7 also starts the second pinion 20 rotating round its axle 21 in the direction shown by another arrow 36.The second pinion 20 finally displaces the launcher 8, one part 11 of which is of a rack-and-pinion shape, in such a way as to cause the coming into contact of its pinion 9 with the crown wheel 10, as shown in chain lines in Fig. 1.

In the course of this process the spring 29 stretched between the ends 27, 28 of the notched belt 25 enables the rotation of the second pinion 20 to differ in relation to that of the first pinion 17, and consequently fulfills the function of the "tooth against tooth" spring.

The other spring 30, which stretches more while the notched belt 25 is displaced in the direction of the arrow 35, fulfils the function of return spring for the launcher after the starting up of the internal combustion engine.

It should be noted that the path of the launcher 8 is not necessarily equal to that of the moving core 14 of the activator 13, the choice of teeth for the two pinions 17, 20 making it possible, on the contrary, to define any rule for the forward movement of the launcher 8 according to the displacement of the activator 1 3.

In one modification shown in the drawing in chain lines on Fig. 2, the activator setting the first pinion 1 7 into motion is composed of an electric power driven reducer 37, replacing the electromagnetic activator with a solenoid 1 3. Thus a rotating activator which can be connected up directly to the pinion 1 7 is put to work in place of an activator displaced in a rectilinear direction. The remainder of the transmission device including the launcher 8 is not modified.

It goes without saying, and it is the result of what goes before, that the invention is not confined to the only form of performance of this starter which has been described above as an example; on the contrary it covers all variations in production and application. Thus the spirit of the invention would not be departed from: : -by replacing the notched belt by an equivalent method of connection, such as a chain, straight rack, etc. which can link two sets of teeth of pinions; -by envisaging, for the "tooth against tooth" spring and/or the return spring of the launcher springs which instead of being linked directly to the notched belt can also be joined to one of the pinions, to the shaft of the activator or to the launcher; -by applying the same device to starters of all types, for example a reduction starter, and in which the motor is not necessarily electric but can also be pneumatic or hydraulic.

Claims

1. A starter for an internal combustion engine, comprising a motor, for example electric, which rotates a launcher comprising a drive and a pinion suitable to be brought into contact with a starter crown wheel carried by the engine to be started, the launcher being capable of axial dispalcement along its shaft and having its axial displacement controlled by an activator, a transmission linking the activator to the launcher including a first rotating pinion rotatable by the moving part of the activator, a second rotating pinion on an axle parallel to the axle of the first pinion and coming into contact with a longitudinally toothed part of the launcher, and connection means between the two pin ions.

2. A starter according to claim 1, in which the first pinion is in contact with teeth of "rack-and-pinion" type formed on a shaft fixed to the moving core of an electromagnetic solenoid activator.

3. A starter according to claim 1, in which the first pinion is rotatable by an electric power-driven reducer.

4. A starter according to any one of claims 1 to 3, in which the second pinion is in contact with teeth of "rack-and-pinion" type formed on the body of the launcher drive.

5. A starter according to claim 4, characterised in that the aforementioned teeth of "rack-and-pinion" type, are formed by alternate grooves and ring shaped ribs.

6. A starter according to any one of the claims 1 to 5, in which the said connection means is a notched belt extending between the two pinions.

7. A starter according to any one of the claims 1 to 5, in which the said connection means is a chain extending between the two pinions.

8. A starter according to any one of the claims 1 to 5, in which the said connection means is a straight rack, coming into contact tangentially with the two pinions.

9. A starter according to the claim 6 or 7, in which the connection means between the two pinions has its two ends joined by a spring stretched between these two ends in such a way as to form the "tooth against tooth" spring.

10. A starter according to any one of the claims 1 to 9, in which a spring is stretched between a point on the connection means and a fixed point of the starter, to form the return spring of the launcher.

11. A starter substantially as hereinbefore described with reference to the accompanying drawings.

1 2. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.