AU7401900A

AU7401900A - Claw-pole alternator

Info

Publication number: AU7401900A
Application number: AU74019/00A
Authority: AU
Inventors: Uwe Knappenberger; Gerhard Pflueger
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1999-08-21
Filing date: 2000-07-29
Publication date: 2001-03-19
Also published as: WO2001015301A1; EP1131877A1; JP2003508003A; DE19939808A1; BR0007028A

Description

WO 01/15301 PCT/DEOO/025 10 1 5 10 Claw-pole alternator Prior Art 15 The invention relates to a claw-pole alternator with a rotor according to the type of the independent claim. Alternators with a rotor in the claw-pole construction are known, for example, from the publication BOSCH Technical Instruction, Alternators, Edition 98/99. The rotor 20 comprises primarily a pole wheel half and a pole support rotationally secured to the pole wheel half by a retaining element. The preferably magnetically non-excitable retaining element is a continuous ring coaxial to the rotational axis of the rotor with a general square cross-section. The pole support and the pole wheel halves feature, on the inner side of the claws facing rotational axis, an approximately cylindrical bore 25 respectively, into which the ring is inserted. The rotor of this known claw-pole alternator has, among other things, the disadvantage that the joint, which can also be a soldered joint, is made approximately midway between the pole support and the pole wheel half over a narrow axial area of 30 the claws. As the free ends of the claw-pole extend freely, they can, under the centrifugal load, bend outwards. A further disadvantage of the known claw-pole alternator is that the radially outwardly directed surface of the claw-poles of the pole WO 01/15301 PCT/DEOO/025 10 2 support and the pole wheel halves is interrupted between the individual antipolar claws, limiting the removal of dissipated heat. 5 Advantages of the invention With the claw-pole alternator of the invention with the characteristic features of the independent claim, it is possible to reduce the size of the gap between the individual claws. At the same time, the joint points of pole wheel halves, retaining elements and 10 pole supports can be better reached from the rear side of the rotor. A connection, which was hitherto achieved by means of brazing the ring to the claw-poles, is now possible by means of welding, as the planned welding points are more easily reachable from outside. As the joint points can be made by means of another procedure, it is possible to enlarge the manufacturing tolerances of the components to 15 be joined: pole wheel halves, restraining elements and pole supports. By this means the manufacturing cost and at the same time the scrap resulting from manufacture is reduced. A further advantage of the at least partial arrangement of the retaining element in the 20 gaps of the claw-poles lies in the enlargement of the outer surface of the rotor, so that the heat dissipation is considerably improved. This improvement of heat dissipation makes possible a higher alternator performance, so that component limiting temperatures, despite the higher performance, are not exceeded. 25 Furthermore, the claw-pole alternator of the invention enables welding also in the area of the free ends of the claw-poles, so that the bending of the claws under the centrifugal load is reduced. This makes possible a small air gap between the outer circumference of the claw-poles and the inner circumference of the stator. 30 By means of the measures listed in the subclaims, advantageous further developments and improvements of the characteristics indicated in the independent claim result.

WO 01/15301 PCT/DEOO/025 10 3 An advantageous design of the retaining element exists by means of the connection of two retaining devices bordering or alongside a claw-pole in the area of a free claw pole by means of a so-called lug. If one bends this lug opposite the rotor shaft axle radially inwardly, then a strengthening of the retaining element is obtained which, 5 through its connection with the claw-pole, additionally strengthens the end of the claw-pole against a flaring under centrifugal load. If one extends the retaining element with the bent lug to an axial outer side of the pole wheel halves until is connects flush with the outer side, then one receives an improved, and less jagged outer side of the rotor. A further improvement of the retaining element is achieved by 10 its design as a one-piece body on which the individual retaining element areas are arranged, which are located between the respective claws. By means of various forming processes one obtains a one-piece retaining element which has a substantially cylindrical structure with alternating open recesses on the pole support and pole wheel side for the pole wheel and pole support claws. A strengthening of the retaining 15 elements can be achieved in that radially inwardly directed arms extend from the ends contiguous to the claw-poles in a largely circumferential direction. This structure is further improved by two adjacent arms being connected in a claw-pole intermediate arm in the area of each claw-pole respectively by means of one web respectively, one web being arranged in the area of the pole wheel claw and the other being arranged in 20 the area of the pole support claw. If one joins two arms to its radially inwardly extending end by a profile-closing element, then a hollow profile results which is consequently further strengthened. If one connects two neighbouring arms of two claw-pole gaps by a pole end web below the claw-poles respectively, then the retaining element is again additionally strengthened. With the aid of the retaining 25 element of the invention, use of permanent magnets in the gaps between two the antipolar claw-poles is possible for the decreasing of leakage flux. Permanent magnets can then be secured, eg. to the retaining element radially inside the rotor. If the retaining element is constructed with a hollow profile within the gaps between antipolar claws, the permanent magnets can be inserted by pushing it into this open 30 hollow profile.

Claims

1. Claw-pole alternator with a rotor (20) in claw-pole construction, the rotor (20) being formed of a pole wheel half (22) fixed to a rotor shaft (32) and a pole 15 support (26) also secured by means of a retaining element (34), the rotor (20) having first claw-poles (28) and second claw-poles (29), the first claw-poles (28) being constructed by the pole wheel half (22) and the second claw-pole (29) being constructed by the pole support (26), the first claw-poles (28) alternating on the circumference of the rotor (20) with the second claw-pole (29) being located 20 between the first claw-poles (28) and the second claw-poles (29) in claw-pole gaps (36), characterised in that the retaining element (34) is arranged at least partially in the claw-pole gaps (36) and the retaining element (34) being fixed, in particular by means of soldering, welding or adhering to the first claw-poles (28) and with the second claw-poles (29). 25

2. Claw-pole alternator according to Claim 1, characterised in that the first claw poles (28) and the second claw-poles (29) have, in particular, radially inwardly extending claw-pole flanks (40), the retaining element (34) on the claw-pole flanks (40) being connected to the pole wheel half (22) and the pole support (26). 30 WO 01/15301 PCT/DEOO/025 10 11

3. Claw-pole alternator according to one of the preceding claims, characterised in that the retaining element (24) consists of a multiplicity of single retaining elements (44). 5

4. Claw-pole alternator according to Claim 3, characterised in that two neighbouring retaining elements (44) in the area of a first and a second free claw-pole end (46, 47) are connected together by means of lugs (48).

5. Claw-pole alternator according to Claim 4, characterised in that the lugs (48) are 10 bent with respect to a rotor shaft (32).

6. Claw-pole alternator according to Claim 4 or 5, characterised in that the lugs on the side of the pole wheel half (22) and/or the pole support (26) connect flush with an axial outer side (50) of the pole wheel half (22) and/or of the pole support (26). 15

7. Claw-pole alternator according to one of the Claims 4, 5 or 6, characterised in that the retaining element (34) consists of one piece, the lugs (48) connecting the retaining elements (44) in one piece. 20

8. Claw-pole alternator according to Claim 7, characterised in that the one-piece retaining element (34) has a substantially cylindrical outer structure which has pole support side and pole wheel side alternating open recesses for the first claw poles (28) and the second claw-poles (29). 25

9. Claw-pole alternator according to one of the Claims 3 to 8, characterised in that arms (54) extend approximately parallel to the first and second claw-pole flanks (46, 57) to both sides of the first and second claw-poles (28, 29) and in a largely radial direction. 30

10. Claw-pole alternator according to Claim 9, characterised in that two opposing arms (54) are connected in one claw-pole gap (36) in the area of a free first and WO 01/15301 PCT/DEOO/025 10 12 second claw-pole end (46, 47) respectively by means of one web (56) respectively.

11. Claw-pole alternator according to Claim 9, characterised in that the arms (54) on 5 their radially inwardly extending ends (62) are connected by means of a profile closing element (60), so that a closed hollow profile (61) results.

12. Claw-pole alternator according to Claim 11, characterised in that the hollow profile (61) is closed on its axial end by means of lugs (48) and is open on its 10 other axial end.

13. Claw-pole alternator according to one of the Claims 5 to 12, characterised in that two neighbouring arms (54) of two claw-pole gaps respectively are connected by means of one pole end web (68) under the first and second claw-pole (28, 29). 15

14. Claw-pole alternator according to one of the preceding claims, characterised in that at least one permanent magnet (70) is fixed to the retaining element (34). 20