RU2542829C2 - Starter drive of internal combustion engine (versions) - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: starter drive comprises a gear wheel and a sheave installed on the starter shaft. The gear wheel moves along the starter shaft with a possibility of engaging in the end position with a gear wheel on the drive flywheel. The sieve has a split ring, from both sides of the split it has holes for pins connecting the ring with a lever. The ratio of the distance between pins connecting the ring with the lever, to the distance from the centre of rotation of the sheave to the pin axis, nearest to it, conforms to the condition of operation of differential freewheel clutch. The lever has a built-in compression spring resting on the split ring with a possibility of rotation clockwise and pressing to the sheave. The lever has a hole where the pin is placed which rotates the gear wheel, installed on the starter shaft. According to the first version - the pins connecting the ring with the lever, and the pin rotating the gear wheel, are located on the same lime line, passing through the sheave centre. According to the second version - the pins connecting the ring with the lever, and the pin rotating the gear wheel, are located on the same lime line, passing through the sheave centre, and the centre of gravity of the lever is shifted along the line of action of the spring with a possibility of occurrence of the centrifugal force acting at the lever rotation against the spring compression force.

EFFECT: improvement of manufacturability of the gear at operation in the mode of freewheel clutch of a starter drive of an internal combustion engine with increase of carrying capacity and longevity, and design simplification.

2 cl, 4 dwg

Description

The invention relates to starting devices of internal combustion engines (ICE), and in particular to starter drives.

Each engine is equipped with a starter. A feature of the work of known starters is that the starter is equipped with an electric motor powered by a rechargeable battery, an overrunning clutch is installed on the electric motor shaft, which drives the gear, which when starting the engine with a special device is put into gear with a gear mounted on the engine's flywheel. After the engine is started, the gear is disengaged from the gear by the same device on the flywheel.

The freewheel transmits torque only in one direction — from the engine to the gear — and is not a turning off device.

Roller overrunning clutches are predominantly used in starters, the disadvantage of which is that the contact of the jamming bodies in the coupling is carried out over small areas, while the normal forces acting in the contact of the jamming bodies are 15-20 times higher than the effective peripheral force. These features of roller overrunning clutches are the reason for their low durability and bearing capacity (RF patent for utility model No. 63887, F16D 41/00, publ. 10.06.2007).

A known ICE starter drive (USSR author's certificate No. 545790, F16D 15/00, published 05.02.1977) containing a drive sleeve mounted on the splines of the shaft connected via a freewheel to the starter gear, in order to increase reliability, the drive sleeve is pivotally connected to the drive element of the freewheel, made in the form of a differential block mechanism.

However, this design is complicated due to the use of a differential shoe brake, consisting of several links that are connected by fingers.

As a prototype, an ICE starter drive was adopted (A.E. Kropp. New overrunning clutches and their applications. Engineering Bulletin. - 2005. - No. 6. P.8-12). The article notes that this mechanism can be used in the ICE starter drive, including the drive gear, moving along the starter shaft with the possibility of engagement in the extreme position with the gear on the drive flywheel, a pulley mounted on the starter shaft, on which a split ring is mounted, on both sides from section provided with holes for pins connecting the ring to the lever, and the ratio of the distance «a» between fingers connecting the ring to the lever, the distance «l» from the center of rotation to the pulley near the axis about him finger satisfies the differential operation freewheel:

$$\beta e^{\mathrm{one},5\pi f}-\mathrm{one}\ge \frac{a}{l}$$

where e is the base of the natural logarithm,

β = 0.8-0.9 - coefficient,

f is the coefficient of friction in the contact of the pulley and the ring.

The article discloses a constructive implementation of the mechanism in the mode of operation of the differential brake, which can be converted into an overrunning clutch or a stop, and it is indicated that in order to convert a differential brake to an overrunning clutch, it is necessary, firstly, to remove the finger from the machine body, in secondly, to make the mechanism permanently closed, for this purpose, the direction of action of the spring should be disconnected and set so that it does not rest on the body. Thus, the article poses a problem, but is not solved.

The present invention solves the problem of creating a mechanism operating in the overrunning clutch mode in the drive of the internal combustion engine starter.

EFFECT: expanding the functional capabilities of the mechanism and increasing its manufacturability when operating in the overrunning clutch mode of the ICE starter drive with increased bearing capacity, durability and simplification of the design.

This technical result is achieved by the fact that, according to version 1, in the ICE starter drive, including a gear moving along the starter shaft with the possibility of engagement in the extreme position with the gear on the drive flywheel, a pulley mounted on the starter shaft on which a split ring is mounted on both sides from section provided with holes for pins connecting the ring to the lever, and the ratio of the distance «a» between fingers connecting the ring to the lever, the distance «l» from the pulley to the rotational center axis of the nearest fell TSA satisfies the differential overrunning clutch operating condition, a compression spring is built into the lever, resting on a split ring with the possibility of turning it clockwise and pressing against the pulley, a hole is made in the lever, into which a finger is inserted, which rotates the gear mounted on the starter shaft, moreover, the fingers connecting the ring to the lever, and the finger that drives the gear, are located on one straight line passing through the center of the pulley;

according to option 2, the center of gravity of the lever is displaced along the line of action of the spring with the possibility of a centrifugal force acting when the lever rotates against the compression force of the spring,

... An increase in the bearing capacity and durability of the starter drive is achieved by the fact that the contact of the jamming bodies is carried out on developed surfaces, which will reduce the mass of the corresponding nodes, increase reliability due to more favorable conditions for the transfer of forces and reduce contact stresses. Differential overrunning clutch, unlike all previously known mechanisms, has the property of being switched off regardless of the relative rotation of the drive and driven parts of the drive, for this it is enough to create a gap between the pulley and the ring by simply changing the direction of the acting force.

The proposed ICE starter drive is shown in the drawings:

figure 1 - the starter drive assembly according to option 1,

figure 2 - section I-I in figure 1,

figure 3 - node drive starter engine according to option 2,

figure 4 is a section I-I in figure 2.

A pulley 2 is mounted on the starter shaft 1, which covers a split ring 3 having holes on both sides of the cut. Fingers 4 and 5 are installed in these holes, connecting ring 3 with lever 6. Fingers 4 and 5 are located on a straight line passing through center O of pulley 2. To select a gap between ring 3 and pulley 2 and create initial friction between these parts in lever 6 a compression spring 7 is built in, which rests on the ring 3 and rotates the lever 5 clockwise. At the same time, in the fingers 4 and 5, forces appear, deforming the ring 3 and pressing it with some small force to the pulley 2. On the same straight line on which the fingers 4, 5 are located, a hole is made diametrically opposite to the center O in the lever 6, into which a finger 8 is installed, connecting the lever 6 with the sleeve 9. The sleeve 9 is freely mounted on the sliding bearings on the shaft 1 of the starter. On the outer surface of the sleeve 9, slots are made on which the gear 10 is mounted, which can occupy two positions on the sleeve 9: the rightmost and the leftmost. With the extreme right position of the gear 10, it is engaged with the gear wheel 11 mounted on the engine flywheel; with the extreme left position of the gear 10, it is disengaged from the gear 11. To move the gear from one extreme position to another, the starter is equipped with appropriate devices that are used here in the same way as in the known starters, and therefore are not described here. To move the gear 10, an annular groove 12 is made in it, into which a fork of the lever moving the gear 10 enters (these fork and lever are not shown in FIG. 1).

Parts 2, 3, 4, 5, 6, 7 and 8 in the described starter drive form a differential overrunning clutch. This clutch transmits torque to the friction between the pulley 2 and the ring 3, that is, it refers to the friction type of overrunning clutches. In order for this clutch to really work as a freewheel, that is, it transmits torque from the drive part to the follower when the drive part rotates in one direction and does not transmit torque when the drive part rotates in the other direction, it is necessary to obtain some mathematical inequality regarding the size of the mechanism, compliance which determines the operation of the coupling. We have obtained the required inequality in the form

$$0,85e^{f\mathrm{one},5\pi }-\mathrm{one}\ge \frac{a}{l}\text{(one)}$$

Where " a " and "l" are the dimensions in the differential freewheel (see figure 1),

e = 2.718 - the base of the natural logarithms,

f is the coefficient of friction in contact between the pulley 2 and the ring 3,

1,5π = α is the angle of the ring 3 of the pulley 2.

The starter drive according to option 1 works as follows.

When starting the engine in the starter, the mechanism for moving the gear 10 from the extreme left to the rightmost position is first turned on. In this case, the gear 10 engages with the gear 11. After that, the starter motor is turned on, and the pulley 2 starts to rotate 2. Since condition (1) is met, the ring 3 and other parts of the overrunning clutch are rotated by friction. As a result, the gear 10 and the gear wheel 11 are rotated. The engine starts.

After starting the engine, the starter motor is disconnected from its power supply, but since the gear 10 is still engaged with the gear wheel 11, there is a danger of destruction of the starter rotor due to its very high rotation speed, because now the leading wheel is 11, which rotates with a frequency engine crankshaft. But at this moment, the overrunning clutch comes into operation, for which the driving and driven parts are interchanged and therefore with the driving gear 11, the overrunning clutch wedges and starts to work in the overtaking mode, that is, the rotation from the gear 11 is not transmitted to the starter shaft.

The next step in existing starters is to remove the gear 10 from engagement with the gear 11. This action is performed by the compression spring 7 in the mechanism for moving the gear 10. As a result, the gear 10 is in its original position, that is, in the leftmost position.

... In the starter drive in option 2, the differential overrunning clutch in option 1 is used to be disabled.

To implement this condition, a compression spring 7 is built into the lever 6. If during the operation of the differential freewheel clutch we create a force Q acting on the lever 6 along the line of action of the spring force 7, which is greater in absolute magnitude and acting in the opposite direction, then the force Q acts on the ring 3 so that a gap is formed between the ring 3 and the pulley 2, and the clutch is disconnected.

To disable the differential overrunning clutch, it is automatically and at the right time that the force Q is centrifugal. For this, the lever 6 is structurally performed so that its center of gravity is located on the line of action of the spring force 7, at point O1, to the right of point O, the center of rotation of the pulley 2. Then, at a certain speed of rotation of the mechanism, the centrifugal force Q will become larger than the force of the spring 7 and disconnect the clutch .

From the design of the starter according to option 2, the mechanism for moving the gear 10 is excluded. Then, the starter drive assembly according to option 2 is arranged as follows. Details 1, 2, 3, 4, 5, 6, 7, 8, forming the starter shaft and differential overrunning clutch in the starter drive assembly according to option 1 (Fig. 1), are completely repeated in the design of the differential overrunning clutch of the starter drive assembly according to option 2 . Except for the design of the lever 6, which, unlike the lever 6 of the starter according to option 1, is made so that its center of gravity is located on the line of action of the spring force 7, but to the right of the point O of the center of rotation of the pulley 2. Condition (1) also turns out to be true for differential overrunning clutch in the starter drive assembly p 2 embodiment.

Finger 8 leads the gear wheel 11, freely mounted on bearings mounted on the starter shaft 1. The gear 10 is in constant engagement with the gear 11 mounted on the engine flywheel.

The starter drive according to option 2 works as follows.

When the engine starts, the starter motor power is turned on and pulley 2 starts to rotate. Since condition (1) is met, the ring 3 and other parts of the overrunning clutch are rotated by friction forces. As a result, the gear 9 and the gear wheel 10 are rotated. The engine is started.

After starting the engine, the starter motor is disconnected from its power supply, but since the gear 10 is engaged with the gear 11, there is a danger of destruction of the starter rotor due to its very high rotation speed; because now the leading one is the wheel 11, which rotates with the frequency of the crankshaft of the wound engine. But at this moment, the overrunning clutch comes into operation, for which the driving and driven parts are interchanged, and therefore with the driving wheel 11, the overrunning clutch is wedged and starts to work in the overtaking mode, that is, the torque from the wheel 11 is not transmitted to the starter shaft. However, the spring 7 creates a certain moment of friction in the contact of the ring 3 and the pulley 2, and this moment of friction may be sufficient to idle spin the starter rotor to a speed that will destroy it. To exclude this scenario, the starter in the lever 6, the centrifugal force at a certain acceptable speed of rotation of the shaft 1 of the starter disables the freewheel by creating a gap between the ring 3 and the pulley 2.

Thus, the gear 10 and parts of the freewheel, except for the pulley 2, rotate at a speed that is determined by the rotation speed of the crankshaft of the engine, and the pulley 2 and the shaft 1 rotate at a speed that is acceptable for the rotor of the starter motor.

As a result, the starter drive according to option 2 provides an increase in bearing capacity and durability in the same way as in the starter according to option 1.

We found on the example of the FIAT starter that as a result of its conversion, the number of parts of which it originally consisted decreased from 47 to 28, that is, decreased by 40%. In proportion to this decrease in the number of parts, it is possible to predict a decrease in the cost of manufacturing a starter, that is, by 40%.

Analysis of known analogues shows that the invention has novelty, the achievement of a new result with a new combination of features indicates compliance with the criterion of "inventive step", model tests confirm its industrial applicability.

Claims (2)

1. ICE starter drive, including a gear moving along the starter shaft with the possibility of engagement in the extreme position with the gear on the drive flywheel, a pulley mounted on the starter shaft, on which a split ring is mounted, provided on both sides of the cut with holes for fingers connecting the ring with the lever, and the ratio of the distance “a” between the fingers connecting the ring with the lever to the distance “l” from the center of rotation of the pulley to the axis of the finger closest to it satisfies the differential driving condition you, characterized in that a compression spring is built into the lever, resting on a split ring with the possibility of turning it clockwise and pressing against the pulley, a hole is made in the lever, into which a finger is inserted, which rotates the gear mounted on the starter shaft, and fingers connecting the ring with the lever, and the finger, which drives the gear, are located on one straight line passing through the center of the pulley. 2. ICE starter drive including a gear moving along the starter shaft with the possibility of engagement in the extreme position with a gear wheel on the drive flywheel, a pulley mounted on the starter shaft, on which a split ring is mounted, provided on both sides of the cut with holes for fingers connecting the ring with the lever, and the ratio of the distance “a” between the fingers connecting the ring with the lever to the distance “l” from the center of rotation of the pulley to the axis of the finger closest to it satisfies the differential driving condition you, characterized in that a compression spring is built into the lever, resting on a split ring with the possibility of turning it clockwise and pressing against the pulley, a hole is made in the lever, into which a finger is inserted, which rotates the gear mounted on the starter shaft, and fingers connecting the ring with the lever and the pin, which drives the gear, are located on one straight line passing through the center of the pulley, the center of gravity of the lever is displaced along the line of action of the spring with the possibility of a centrifugal force acting when aschenii lever against the spring force.

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