GENERATOR

Abstract: Ignition- and/or generator system, for example, in an engine, including a flywheel (1) of non-magnetic material or low-magnetic material, such as aluminium. The flywheel (1) surrounds a stator with at least one winding. At least one permanent magnet is arranged on the inner surface of the flywhell. The invention is characterised in that an integrated part (5) of magnetic material that includes a combined feedback ring (6) and a counter ring (7) is arranged on the flywhell (1). A starting ring can be included in the integrated part.

Description: Generator DESCRIPTION Technical Field The invention concerns an ignition- and generator system that includes a flywheel of non-magnetic or low-magnetic material, which flywheel has at least one permanent magnet at its inner circumference. The flywheel surrounds a stator with its windings. The Background Art In certain engines, including several types of motorcycle engines, the power requirements for the vehicle are directly generated by a flywheel- and generator system. The stator of the generator is mounted on the inner surface of the flywheel and permanent magnets are arranged in the flywheel. A change in magnetic flux is created when the flywheel is set in motion, whereby an electrical voltage is produced in the windings of the stator. In several engines it is interesting to keep the flywheel weight of the flywheel as low as possible. As a result, aluminium, for example, is chosen as the material for the flywheel. In order to reinforce the magnetic field that is produced with the aid of the permanent magnets, it is necessary to mount ferromagnetic material in direct contact with the permanent magnet or magnets. One example of this is what is known as a "feedback ring". The permanent magnet or magnets are then mounted on the inner surface of the feedback ring, for example in the shape of a ring. Furthermore, the mounting of devices on the flywheel in order to measure such factors as the rotation speed, the position of the engine and the direction of rotation of the engine, is also known. Such a device is usually in the form of what is known as a counter ring, measurement ring or measurement wheel. Both a feedback ring and a counter ring are often used on flywheels manufactured from non-magnetic or "low-magnetic" material. The expression "low-magnetic material" is used here to denote a material in which it is both desirable and possible to reinforce the magnetic field that is produced by permanent magnets that are mounted in the vicinity of the flywheel. The counter ring and the feedback ring have up until now been two distinct and separate components. The feedback ring has been placed, fixed for example by a glued connection, or arranged directly in association with casting of the flywheel, somewhere on the inner surface of the wheel. The counter ring, which must be implemented with precision, has been mounted in a precision-turned groove, for example using shrink- and pinned connections, to the outer surface of the wheel. This method of mounting is expensive to carry out since two separate components, each with relatively high requirements for precision must first be manufactured, and then the components must each be mounted with precision. The mounting of the counter ring onto the flywheel, in particular, requires high precision. Summary of the Invention The present invention comprises a system for alleviating the disadvantages of known ignition- and/or generator systems. The advantages of the system are thus a safe and durable ignition- and generator system that is simpler and cheaper to produce, and that is characterised in that an integral part of magnetic material is arranged on the flywheel that includes a combined feedback ring and counter ring. A significant saving can be achieved with the suggested system with an integrated feedback ring and counter ring since it is only necessary to produce one component and since the mounting can be carried out in one and the same operation, for example in association with casting the flywheel. The flywheel is preferably constructed from aluminium. Zinc, titanium or magnesium comprise alternative materials. The teeth, cogs or similar of the counter ring, which are located on the outer surface of the flywheel, are uncovered after the casting. It is an advantage, however, to preserve an aluminium layer over the cogs of the counter ring, in order to protect from corrosion. According to another embodiment, the capacity of the flywheel can be adjusted by varying the height of the cogs of the counter ring. Other features of the invention are made clear by the attached claims. In summary, the advantages of an integrated counter ring and feedback ring according to the invention are as follows: - the durability of the finished flywheel is higher than in the case where the counter ring is mounted separately, since the counter ring is embedded of the flywheel and is thus a part of it, - it is possible to achieve total protection from corrosion by preserving a thin layer of aluminium on the outer diameter of the flywheel, outside of the cogs of the counter ring, - the flywheel weight of the flywheel can be easily adjusted and adapted by varying the height of the cogs of the counter ring, - the work invested and the total cost become significantly lower compared to the case when two components are used. Description of embodiments The invention will now be described in more detail with the aid of the attached drawing where: Figure 1 shows a view in perspective of a section through a flywheel. Figure 1 shows a cross-section of a flywheel 1. The flywheel is made out of a non-magnetic material, preferably aluminium. The use of other materials, such as zinc, titanium, magnesium or other suitable non-magnetic metals, alloys or plastics is, of course, possible. The flywheel is shaped as a disc 2 with a hole 3 for an engine shaft. The circumference of the disc has an axially placed edge 4 whose inner surface is essentially axial and whose outer surface is essentially axial. An integrated part 5, which includes a combined feedback ring 6 and counter ring 7, is arranged with the flywheel 1 such that the feedback ring 6 makes contact with the inner surface of the edge 4. The counter ring 7 has cogs, measuring tips or teeth that face the outer surface of the flywheel. In the embodiment shown, the integrated part 5 is cast simultaneously with the casting of the flywheel. Other methods of production are also possible. The cogs of the counter ring are uncovered after casting by processing of the outer diameter of the flywheel. However, in order to protect the cogs from corrosion, a thin layer of aluminium can be preserved over the cogs. Certain types of sensor, such as a Hall sensor, can detect the cogs of the counter ring even through a thin aluminium layer. One or more permanent magnets (not shown) are mounted in a suitable manner, for example in the shape of a ring, on the inner surface of the feedback ring 6 of the integrated part. The weight of the flywheel can be adjusted in a simple manner by varying the height of the cogs of the counter ring 7. The cogs of the counter ring 7 have a rectangular shape in the embodiment that is shown, but it is clear that they can have another suitable shape. The cogs can lie flush with the outer diameter of the flywheel or the can protrude beyond the outer diameter of the flywheel. The integrated part 6 can also include a starting ring with protruding cogs for engagement with a start motor. The invention is intended for use in an engine.

Claims: CLAIMS 1. Ignition- and/or generator system including a flywheel (1) of non-magnetic material or low-magnetic material, surrounding a stator with at least one winding, whereby at least one permanent magnet is arranged on the inner surface of the flywheel, characterised in that an integrated part (5) of magnetic material that includes a combined feedback ring (6) and a counter ring (7) is arranged on the flywheel (1). 2. System according to claim 1, characterised in that the flywheel (1) is constructed from aluminium, zinc, titanium or magnesium. 3. System according to claim lcharacterised in that the integrated part (5) is cast into the flywheel (1). 4. System according to any of the preceding claims, characterised in that the said permanent magnets, possibly in the shape of a ring, are mounted on the inner surface of the feedback ring of the integrated part. 5. System according to claim 3, characterised in that the counter ring (7) has cogs that are located on the outer surface of the flywheel (1) and that are uncovered after the casting. 6. System according to claim 5, characterised in that a protective aluminium layer is preserved over the cogs of the counter ring (7). 7. System according to any of the preceding claims, characterised in that the weight of the flywheel is adjusted by varying the height of the cogs of the counter ring. 8. System according to any of the preceding claims, characterised in that the cogs of the counter ring protrude beyond the outer diameter of the flywheel. 9. System according to any of the preceding claims, characterised in that a starting ring with cogs is included in the integrated part of the flywheel. 10. Use of the system according to any of the preceding claims in an engine.

Inventors: ANDERSSON CONNY, BENGTSSON JOERGEN, ANDERSSON, CONNY, BENGTSSON, JOERGEN
Applicants: ANDERSSON CONNY, BENGTSSON JOERGEN, SEM AB, ANDERSSON, CONNY, BENGTSSON, JOERGEN
Application year: 2000
Main classification: F02P1
IPC codes: F02P1, H02K1, H02K7, H02K11, H02K21