JPH05248327A - Internal combustion engine starter for motor vehicle - Google Patents

Abstract

PURPOSE: To minimize the size and reduce the weight of a starter, and simultaneously enable the starter to stand strict corrosion resistant test. CONSTITUTION: A starter 1 comprises an electric motor 7 having a stator 8 with at least eight poles 9 and a rotor 11. The shaft of the motor is torsionally coupled directly to a heat engine driven pinion 30. The whole starter is enclosed in a protective casing 2, 3 of non-magnetic material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starter for an automobile internal combustion engine. More specifically, the invention relates to a support structure, a pinion translatable with respect to the structure and also adapted to mesh with a gear of an internal combustion engine, between a rest position and an operating position. The present invention relates to a starter having a control electromagnet having a movable iron core, a transmission between the iron core of the electromagnet and the pinion, and a DC electric motor that can be fed as a result of the excitation of the electromagnet that rotationally drives the pinion.

[0002]

2. Description of the Prior Art Starters of this type have been and have been manufactured in large numbers to date. In this type of starter, the rotary shaft of the electric motor is torsionally connected to a translation pinion and to a one-way clutch, typically of the freewheel type, via a reduction gear, for example of the planetary gear type.

In this type of starter, when the electromagnet is energized, its iron core is attracted towards its operating position, via said transmission (which is often a simple fork-like arm). Causes a translational motion of the pinion.
The pinion thereby meshes with the teeth of a gearwheel (freewheel) that can rotate the crankshaft of the heat engine.

Electromagnets are commonly associated with switches having movable contacts. The movable contact is displaced by the translational movement of the iron core and closes the power supply path to the electric motor at the end of the pinion stroke.

When the heat engine starts and its rotation rate exceeds a predetermined value, the one-way clutch disengages the electric motor from the pinion to prevent damage to the motor.

When the excitation of the electromagnet is stopped, the pinion is
Immediately removed from the gears of the engine. There are many problems in manufacturing this type of starter.

In fact, this type of starter must be robust, reliable and at the same time small and quiet. Automakers also require starters to pass a long-term tolerance test in harsh environments (eg, 100 hours or more in salt or fog). In order to satisfy such requirements,
It has also been attempted to galvanize the outer surface of the casing of the electromagnet and the electric motor, for example. This is because the electromagnet and the electric motor are usually made of a magnetic material that does not have strong tolerance to the corrosive medium.

However, this plating solution solves at least some of the above problems, but from the perspective of cost, environmental pollution, and the flexibility and adaptability of this process to the required changes in productivity, It has considerable disadvantages.

[0009]

SUMMARY OF THE INVENTION The object of the invention is at the outset to be smaller and significantly lighter than a conventional starter, while at the same time being able to withstand more rigorous tests on corrosive media. To get a different type of starter.

[0010]

This object has been achieved according to the invention by providing the starter mentioned at the outset with the following basic characteristics. That is, the electric motor is provided with a stator having at least 8 poles and a rotor having a shaft directly torsionally coupled to the pinion, and the entire starter is housed in a protective casing made of a non-magnetic material. I decided to do it.

By adopting a stator with at least 8 poles, the dimensions of the starter electric motor, especially in the axial direction, can be considerably reduced.

Direct transmission of rotation from the rotor of the electric motor to the pinion, that is, transmission without a reduction unit in the middle, also makes it possible to reduce the size, weight and cost. The absence of a reduction unit also significantly reduces the generation of noise by the starter during operation.

The direct torsional connection (ie, gear ratio 1) between the rotor and pinion of the electric motor provides a conventional one-way clutch or, preferably, another means that does not rely on such a clutch. It can be achieved by using.
Of course, in the case of this second means, in order to prevent damage to the electric motor of the starter at the time of starting the heat engine, an electronic start control system of a known type can be adopted.
These systems, for example, provide a sensor that provides a signal indicating the rotational speed of the crankshaft of the heat engine and a starter signal when the signal from the sensor indicates that the engine rotational speed has reached a predetermined minimum self-sustaining speed value. And an electronic control unit for shutting down.

Due to the size and weight reductions achieved by the arrangements described above, the weight of the protective casing of non-magnetic material of the entire starter is at least acceptable, if not negligible.

The cooperation of the set of parts according to claim 1 thus makes it possible to achieve the above-mentioned object which is the basis of the invention.

[0016]

Other features and advantages of the present invention will now be described with reference to the accompanying drawings. However, the illustrated embodiments do not limit the present invention.

In FIG. 1, a starter for an internal combustion engine of a motor vehicle is generally designated by reference numeral 1. The starter 1 has a support casing. This casing is formed by two shell halves 2, 3 in the illustrated embodiment. The shell halves 2, 3 are fitted together and are connected (in a known manner) by fastening screws. The shell halves are made of a lightweight, non-magnetic material such as a thermosetting plastic material or the like, preferably aluminum or one of its alloys. In the example shown, the shell half 2 has an edge 2a into which the shell half 3 is inserted.
The corresponding edge portion 3a is fitted.

As can be seen better by comparing FIGS. 1 and 2, the shell halves 2, 3 together form a casing. This casing is substantially 8
It has a V-shaped cross section and has an upper section 4 and a lower section 5, which are connected by an intermediate section 6.

A DC electric motor 7 is housed in the lower casing area, which is designated by the reference numeral 5 in FIG. This motor has a stator 8. The stator 8 is constructed by depositing a thin layer with eight (at least) polarity-increasing parts or poles 9 on the inner surface, each with a stator winding 10.

The poles of the stator may be permanent magnets instead of windings. A rotor 11 is arranged in the stator 8 of the electric motor 7. The rotor 11 has a plurality of recesses 12 on its peripheral surface, and has a conductor 13 therein.

The rotor 11 has, for example, 21 recesses, and each of the recesses accommodates four conductors. The rotor 11 can be made extremely compact and in particular can have very small axial dimensions. The sleeve 15 is axially slidable in the shell half 2 on the shaft of the motor 7 in a known manner.

Reference numeral 16 denotes a rocker lever arranged in the shell half 2. The rocker lever 16 is
It is rotatable about a fulcrum 17 and serves as a transmission member between the sleeve 15 and the extension 18a of the iron core 18 of the electromagnet. The electromagnet is generally designated 19 in FIG.
It is indicated by. The electromagnet 19 has a tubular casing 20 (FIG. 2) made of a magnetic material. This casing 2
In 0, an exciting solenoid 21 is arranged while being held by a coil 22. The iron core 18 is translatable in the coil 22 in the axial direction.

The rocker lever 16 was previously described in patent application 53
828-A / 85 is advantageously manufactured and thus has a forked fork shape which engages corresponding seats on opposite sides of the sleeve 15. .. Only one side of the sleeve can be seen in FIG.

Reference numeral 30 in FIG. 1 indicates a pinion.
This pinion is translatable in a known manner with respect to the seven axes of the electric motor. This translation is the result of a corresponding translation of the sleeve 15 due to the excitation of the electromagnet 19.

The pinion 30 is connected to the shaft of the electric motor 7. This connection is of the type that rotates at a transmission ratio of 1: 1 without any reduction gear unit. This type of connection can be achieved, for example, by a spline joint.

When the electromagnet 19 is excited, the iron core 18 is displaced and causes translational movement of the sleeve 15 and the pinion 30 via the rocker lever 16. The pinion 30 is pushed into engagement with the teeth of a gear 40 (FIG. 1) that is rotationally connected to the crankshaft of the internal combustion engine being started. Gear 40
Is, for example, the flywheel of the engine.

Similar to the conventional starter, when the pinion 30 meshes with the gear 40, a switch (not shown, completely conventional) combined with the electromagnet 19 energizes the motor 20 having a shaft for rotating the pinion. To be done.

As mentioned above, the starter of the present invention preferably does not include a one-way clutch. In that case, the starter is combined with an electronic control system to stop the electric motor 7 as soon as the heat engine reaches or exceeds the minimum self-sustaining speed.

However, the starter of the present invention may also employ a one-way clutch operable to torsionally disengage the pinion from the electric motor shaft when the internal combustion engine exceeds self-sustaining speed.

The use of a stator with multiple poles, the elimination of a reduction unit, the optional use of a one-way clutch significantly reduces the size and weight of the starter. In particular,
It is possible to produce a starter whose weight is considerably less than 3 kg while using an electric power of about 1 kW.

Such a significant reduction in weight and size makes the increase in weight and size due to the use of corrosion resistant non-magnetic casings acceptable and almost negligible. By this, the objects mentioned at the beginning of the present specification can be completely achieved.

In another embodiment, the starter does not have an integral casing made of aluminum or its alloys, for example Italian patent application 54288-B /
It is also possible to have a conventional support structure according to 85, in particular a casing for the electromagnet and the electric motor stator, which is not enclosed in a casing made of a non-magnetic metallic material. In this case, instead of the metal coating, it is conceivable to coat with a shrinkable plastic material.

The details of the embodiments and configurations may be changed without departing from the principles of the invention, and the illustrated embodiments are merely given as non-limiting examples.

[Brief description of drawings]

FIG. 1 is a side view of a starter according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

[Explanation of symbols]

 1 Starter 2, 3 Shell half part 2a, 3a Edge part 4 Casing upper part 5 Casing lower part 6 Casing middle part 7 Electric motor 8 Stator 9 Pole 10 Stator winding 11 Rotor 13 Conductor 17 Support point 18 Iron core 19 Electromagnet 21 Solenoid 30 Pinion

Claims (5)

[Claims] 1. A starter for an internal combustion engine of an automobile, comprising:
A support structure (2,3), a pinion (30) translatable with respect to the structure (2,3) and also adapted to mesh with a gear (40) of the internal combustion engine, and a rest position. A control electromagnet (1) having an iron core (18) movable between an operating position and
9) and the iron core (18) and pinion (3) of the electromagnet (19)
0) and the pinion (3).
0) a DC electric motor (7) fed by excitation of an electromagnet (19) for rotating the electric motor, the electric motor (7) having a stator (8) having at least 8 poles (9); A rotor (11) having a shaft (14) directly screw-connected to the pinion (30), and the entire starter (1) is housed in a protective casing (2, 3) of non-magnetic material. Is characterized by
Starter for internal combustion engine of automobile. 2. The casing (2, 3) is made of aluminum or an aluminum alloy,
The starter according to claim 1. 3. Starter according to claim 1, characterized in that the casing (2, 3) is made of a thermosetting plastic material. 4. Starter according to claim 1, characterized in that the casing (2, 3) is made of a heat-shrinkable plastic film. 5. The casing (2, 3) has a figure 8 cross section, and also the housing upper section (4) carries the electromagnet (19) and the housing lower section (5) carries the electric motor (7). ) Is surrounded, The starter of Claim 2 or 3 characterized by the above-mentioned.