GB2056184A

GB2056184A - Electrical generator

Info

Publication number: GB2056184A
Application number: GB8020232A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1979-06-22
Filing date: 1980-06-20
Publication date: 1981-03-11
Also published as: JPS566643A; DE2925219A1

Abstract

A heteropolar generator rotor (18, 19) for a battery-charging system forms part of a flywheel (27) of an internal combustion engine and is housed in the gearbox (25). A generator of this kind can be used to special advantage in internal combustion engines in motor vehicles. <IMAGE>

Description

SPECIFICATION Electrical generator The invention relates to generators to be driven by internal combustion engines, e.g., a vehicle generator of a battery charging system.

Such a generator is normally driven by the engine crankshaft by way of pulley wheels and a V-belt. This has the disadvantage that the generator is a separate component and is subjected to mechanical damage and soiling.

Furthermore, the drive mechanism for the generator is fairly expensive and is susceptible to trouble.

The invention resides in a generator to be driven by an internal combustion engine, in which the generator is a heteropolar generator and its rotor is secured to the flywheel of the internal combustion engine.

This has the advantage that the generator is accommodated within the internal combustion engine so as to be mechanically protected. A further advantage is that the generator is cooled within the engine block and is maintained at a constant temperature.

It is particularly advantageous that the generator contributes to reducing the weight of the engine by virtue of the fact that the generator is integrated with the flywheel. By using the flywheel jointly as the rotor, the weight of the generator itself is reduced solely to the weight of the stator. The stator does not have to overlie the entire circumference of the rotor, so that the generator can be of flat construction.

Advantageously, the stator is sub-divided into a plurality of segments, to enable individual load circuits, such as loads having a different nominal voltages, or d.c. and a.c. voltage loads, can be connected to different stator segments.

The invention is further described, by way of example, with reference to the drawings, in which: Figure 1 is a diagrammatic elevation of a generator according to the invention, showing the mechanical construction and the position of the windings, and Figure 2 is a view into an engine housing having the generator in accordance with the invention.

Figure 1 shows, diagrammatically, the construction of a heteropolar generator which is used to charge a vehicle battery. A stator 11 carries an excitation winding 12, an a.c. winding 13 and a compound winding 14. The three windings are connected in the conventional manner. The three windings 12, 13, 14 are located in slots 1 5 between teeth 1 6. The teeth 1 6 are directed radially inwardly towards the centre point 1 7 of the generator from the outer circumference of the stator 11. The rotary axis of the generator stands upright on the plane of the drawing and also extends through the centre point 17. A rotor 1 8 is mounted within the stator 11 so as to be rotatable about the axis 1 7.The rotor also has teeth 1 9 which, however, are directed outwardly towards the stator 11. In the present embodiment of the invention, the stator 11 and the rotor 1 8 are of laminated construction.

Figure 2 is a view into the housing of an internal combustion engine, particularly a view of the flywheel and the clutch. The only parts of this arrangement which will be described are those which are of importance for comprehension of the invention. A crankshaft 21 having a web 22 is journalled in the housing 24 of the internal combustion engine by means of a journal bearing 23. A gearbox 25 is mounted on the engine housing 24 and contains, inter alia, the clutch 26.

The gearbox 25 also encloses a flywheel 27 which is bolted to the crankshaft 21 by means of bolts 28.

The laminations of the rotor 1 8 are mounted on the flywheel 27. The tooth 19 can also be seen in Figure 2. The laminations of the stator 11 are fitted in the gearbox 25. A portion of the windings 12, 13, 14 is shown in Figure 2. It will be appreciated that the rotor 1 8 and the stator 11 are located radially opposite one another.

It is not necessary for the stator 11 to extend around the entire circumference of the rotor 1 8.

Owing to the relatively large diameter of the rotor 18, determined by the diameter of the flywheel 27, the required output of the generator can be supplied by a stator 11 which covers only a portion of the circumference of the rotor 1 8. In the present embodiment, the stator 11 extends through approximately 1 80C only around the upper half of the rotor 1 8. However, this is only an example, and other data are possible or can be advantageous.

Although it is not shown in the drawings, it will be readily appreciated that it is possible to subdivide the stator 11 into a plurality of segments and to arrange it in the gearbox in conformity with the stator part 11 of Figure 2. By way of example, each individual segment can then feed an individual part of the vehicle electrical system, for example with a different voltage, or with an a.c. voltage.

In the present invention, the moment of inertia of the flywheel 27 can be reduced by the moment of inertia of the rotor 1 8. Thus, the rotor 1 8 does not constitute any additional weight, and only the weight of the stator 11 constitutes the weight of the generator.

1. A generator to be driven by an internal combustion engine, in which the generator is a heteropolar generator and its rotor is secured to the flywheel of the internal combustion engine.

2. A generator as claimed in claim 1, in which only the stator of the generator carries windings.

3. A generator as claimed in claim 1 or 2, in which the rotor is secured chiefly to the radial outer circumference of the flywheel.

4. A generator as claimed in any of claims 1 to 3, in which the stator is fixed with respect to the engine housing so as to lie radially opposite the

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Electrical generator The invention relates to generators to be driven by internal combustion engines, e.g., a vehicle generator of a battery charging system. Such a generator is normally driven by the engine crankshaft by way of pulley wheels and a V-belt. This has the disadvantage that the generator is a separate component and is subjected to mechanical damage and soiling. Furthermore, the drive mechanism for the generator is fairly expensive and is susceptible to trouble. The invention resides in a generator to be driven by an internal combustion engine, in which the generator is a heteropolar generator and its rotor is secured to the flywheel of the internal combustion engine. This has the advantage that the generator is accommodated within the internal combustion engine so as to be mechanically protected. A further advantage is that the generator is cooled within the engine block and is maintained at a constant temperature. It is particularly advantageous that the generator contributes to reducing the weight of the engine by virtue of the fact that the generator is integrated with the flywheel. By using the flywheel jointly as the rotor, the weight of the generator itself is reduced solely to the weight of the stator. The stator does not have to overlie the entire circumference of the rotor, so that the generator can be of flat construction. Advantageously, the stator is sub-divided into a plurality of segments, to enable individual load circuits, such as loads having a different nominal voltages, or d.c. and a.c. voltage loads, can be connected to different stator segments. The invention is further described, by way of example, with reference to the drawings, in which: Figure 1 is a diagrammatic elevation of a generator according to the invention, showing the mechanical construction and the position of the windings, and Figure 2 is a view into an engine housing having the generator in accordance with the invention. Figure 1 shows, diagrammatically, the construction of a heteropolar generator which is used to charge a vehicle battery. A stator 11 carries an excitation winding 12, an a.c. winding 13 and a compound winding 14. The three windings are connected in the conventional manner. The three windings 12, 13, 14 are located in slots 1 5 between teeth 1 6. The teeth 1 6 are directed radially inwardly towards the centre point 1 7 of the generator from the outer circumference of the stator 11. The rotary axis of the generator stands upright on the plane of the drawing and also extends through the centre point 17. A rotor 1 8 is mounted within the stator 11 so as to be rotatable about the axis 1 7.The rotor also has teeth 1 9 which, however, are directed outwardly towards the stator 11. In the present embodiment of the invention, the stator 11 and the rotor 1 8 are of laminated construction. Figure 2 is a view into the housing of an internal combustion engine, particularly a view of the flywheel and the clutch. The only parts of this arrangement which will be described are those which are of importance for comprehension of the invention. A crankshaft 21 having a web 22 is journalled in the housing 24 of the internal combustion engine by means of a journal bearing 23. A gearbox 25 is mounted on the engine housing 24 and contains, inter alia, the clutch 26. The gearbox 25 also encloses a flywheel 27 which is bolted to the crankshaft 21 by means of bolts 28. The laminations of the rotor 1 8 are mounted on the flywheel 27. The tooth 19 can also be seen in Figure 2. The laminations of the stator 11 are fitted in the gearbox 25. A portion of the windings 12, 13, 14 is shown in Figure 2. It will be appreciated that the rotor 1 8 and the stator 11 are located radially opposite one another. It is not necessary for the stator 11 to extend around the entire circumference of the rotor 1 8. Owing to the relatively large diameter of the rotor 18, determined by the diameter of the flywheel 27, the required output of the generator can be supplied by a stator 11 which covers only a portion of the circumference of the rotor 1 8. In the present embodiment, the stator 11 extends through approximately 1 80C only around the upper half of the rotor 1 8. However, this is only an example, and other data are possible or can be advantageous. Although it is not shown in the drawings, it will be readily appreciated that it is possible to subdivide the stator 11 into a plurality of segments and to arrange it in the gearbox in conformity with the stator part 11 of Figure 2. By way of example, each individual segment can then feed an individual part of the vehicle electrical system, for example with a different voltage, or with an a.c. voltage. In the present invention, the moment of inertia of the flywheel 27 can be reduced by the moment of inertia of the rotor 1 8. Thus, the rotor 1 8 does not constitute any additional weight, and only the weight of the stator 11 constitutes the weight of the generator. CLAIMS

4. A generator as claimed in any of claims 1 to 3, in which the stator is fixed with respect to the engine housing so as to lie radially opposite the outer circumference of the rotor.

5. A generator as claimed in claim 4, in which the stator is secured to a gearbox attached to the engine.

6. A generator as claimed in claim 5, in which the stator is attached to a part of the gearbox which encloses a clutch.

7. A generator as claimed in any preceding claim, in which the stator is in the form of a segment and covers only a portion of the outer circumference of the rotor.

8. A generator as claimed in claim 7, in which the stator extends substantially over an angle of 180 .

9. A generator as claimed in any preceding claim, in which the stator is sub-divided into a plurality of segments having output windings which are electrically separated from one another.

10. A generator as claimed in claim 9, in which an individual load circuit is connected to the windings of each of the segments of the stator.

11. A generator constructed substantially as herein described with reference to and as illustrated in the drawings.