Method for winding an armature body of an armature, and electric machine provided with an armature produced by the method

Abstract: Method for winding an armature body, provided with armature slots, of an armature having a commutator mounted on an armature shaft and having commutator segments provided with attachment elements. In the method, winding wire (200) is fed through the armature slots (101-124) in accordance with a winding cycle and is attached to the attachment elements (1a-24a) of the commutator segments (1-24) to form a first set of coils, the coils being electrically connected to one another via the commutator segments. After finishing the winding cycle mentioned, an additional winding cycle is carried out, winding wire (200) again being fed through the armature slots (101-124) already provided with coil sides of the coils of the first set and being attached to the attachment elements (1a-24a) of the commutator segments (1-24) to form a second set of coils electrically connected in parallel with the coils of the firstmentioned set.

Description: The invention relates to a method for winding an armature body, provided with armature slots, of an armature having a commutator mounted on an armature shaft and having commutator segments provided with attachment elements, winding wire being fed through the armature slots in accordance with a winding cycle and being attached to the attachment elements of the commutator segments to form a set of coils, the coils being electrically connected to one another via the commutator segments. The invention also relates to an electric machine provided with a stator and an armature. The method as described above is generally known and can be carried out with winding machines which are commercially available. Such a winding machine is described, for example, in US-A-3 973 738. The known method is used to provide a drum-type armature body provided with radial armature slots with a winding distributed over a number of coils, starting from a winding wire which is wound around a hook-type attachment element of a commutator. For the purpose of forming a first coil, the winding wire is then fed a required number of times through two approximately diametrically situated armature slots and finally wound around a further hook-type attachment element of the commutator. The winding wire is then again fed through two armature slots and wound round yet another hook-type attachment element to form a second coil. This last operation is repeated sufficiently often for the number of required spools to be formed, after which two of the spools are connected to each other via each commutator segment of the commutator by connecting the coil ends electrically to the commutator segments by bending over and heating the hook-type attachment elements. The winding time of the known method can be shortened by using two winding wires, as a result of which symmetrical winding is possible, two coils being formed at the same time. The known method is suitable for using thin winding wire, for example copper wire having a diameter of less than 0.50 mm. For various applications, for example certain electric motors which are designed for a mains voltage of 100 to 120 V, it is necessary, for considerations of temperature, to use a thicker winding wire, for example copper wire having a diameter of greater than 0.60 mm. It has been found, however, that the percentage of rejects increases if thicker wire is used, inter alia because, after winding, coil ends touch each other at the attachment elements of the commutator or because an attachment hook is mechanically deformed during the breaking of the wire which is brought about at the end of winding by a pulling movement. The object of the invention is, inter alia, to alter the known method in a manner such that the field of application is extended without the risk of rejection increasing as a result. The method according to the invention is characterized for this purpose in that, after finishing the winding cycle mentioned, at least one additional winding cycle is carried out, winding wire again being fed through the armature slots already provided with coil sides of the coils of the set mentioned and being attached to the attachment elements of the commutator segments already connected to the coils of the set mentioned to form a further set of coils electrically connected in parallel with the coils of the first-mentioned set. An advantage of the method according to the invention is that it is now possible to produce armatures for which relatively thick wires are required for electrical engineering reasons by winding an armature body with thin wire which can be wound without difficulty. An additional, but not unimportant, advantage is that a commutator of relatively small dimensions can be used. Moreover, the method according to the invention results in a beneficial filling factor of the armature slots. Although the method according to the invention may take somewhat longer than the known method, that is outweighed by the advantages obtained. An embodiment of the method according to the invention has the characteristic that the winding cycles mentioned are carried out immediately after each other, the winding wire not being broken on passing from the one cycle to the other cycle. An advantage of this is that, at the beginning of the additional winding cycle, the winding wire is already attached to the correct attachment element of the commutator, which saves an operation and shortens the total winding time. A further embodiment has the characteristic that the winding cycles mentioned are carried out in identical manners to each other. In this manner, coils having a mutually number of windways and connected in parallel are formed. The object of the invention is furthermore to provide an electric machine of the type mentioned in the preamble, in which the armature has been produced by the method according to the invention, which machine is characterized in that two coil sides of a first set of coils electrically connected via a commutator and two coil sides of at least one further set of coils electrically connected via the commutator are present in each armature slot. In such a machine, a beneficial thermal economy can easily be achieved. The invention is illustrated in more detail by way of example with reference to the drawing, wherein Fig. 1 shows, partly in longitudinal section and partly in side elevation, a part of an electric machine according to the invention; Fig. 2 is a diagrammatic cross section II-II of the machine according to Fig. 1, and Fig. 3 is a winding diagram of the machine according to Fig. 1. The machine according to the invention shown in Fig. 1 and 2 is constructed as a series-wound motor and is suitable for connecting to 100-120 volt alternating voltage mains. The electric motor has a stator 50, only shown in part, having stator coils 51 and a rotor or armature 52 having an armature winding. The armature 52 comprises a drum-type armature body 56, an armature shaft 58 and a commutator 60. Radially directed armature slots for accommodating coil sides are provided in the armature body 56 which is mounted on the armature shaft 58 and which is formed as a laminated core. In this example, the number of armature slots is twenty-four and the armature slots are indicated by the reference numerals 101-124. The armature shaft 58 is mounted on two bearings 62 and 64 so as to be rotatable around its centre line 58a. The commutator 60, also mounted on the armature shaft 58, has twenty-four commutator segments 1-24, each of which is provided with a hook-type attachment element termed a commutator hook for short, 1a-24a. The commutator winding comprises, in this exemplary embodiment, two sets each containing twenty-four, essentially rectangular coils which are indicated diagrammatically in the drawing by 201-224 and 225-248 respectively. The armature winding which is provided by the method according to the invention is now dealt with in more detail, reference being made at the same time to the winding diagram of Fig. 3. As can be deduced from the winding diagram, a winding wire 200, formed by an insulated copper wire having a diameter of 0.40 mm, is attached to one of the commutator hooks. In Fig. 3, this is, by way of example, the commutator hook 1a. The attachment can be carried out by winding the winding wire 200 around the hook a few times. After the attachment mentioned, the winding wire is fed a predetermined number of times in the form of a loop through two of the armature slots, namely the armature slots 101 and 115, and then wound around the commutator hook 2a. From this point, the winding wire is again fed through two armature slots, in this case the armature slots 102 and 116 and then wound around the commutator hook 3a. Feeding the winding wire through the armature slots is repeated twenty-two times in this example, the winding wire running from the commutator hook 24a via the armature slots 124 and 114 to the commutator hook 1a in the case of the twenty-fourth time. The winding cycle described above is partly and diagrammatically shown by full lines in the winding diagram of Fig. 3. After carrying out completely the winding cycle described above, in which one of the sets of twenty-four coils of, for example, every eighteen windings, namely the coils 201-224, are formed, the winding cycle is completely repeated yet again, starting and finishing again at the commutator hook 1a, the other set of coils 225-248 being formed. In the winding diagram of Fig. 3, the additional winding cycle is partly shown diagrammatically by broken lines. The armature 52 wound by the method according to the invention has the characteristic that two coil sides of the set of coils 201-224 and also two coil sides of the set of coils 225-248 are accommodated in each armature slot 101-124. The armature 52 furthermore has the characteristic that a coil of the one set is always electrically connected in parallel with a coil of the other set, and this provides a relatively low substitutional resistance of the winding, which results in a beneficial motor efficiency. For the sake of completeness, it is pointed out that, to shorten the winding time, it is possible in a practical embodiment to use more than one winding wire, for example two winding wires which, at the beginning of a winding cycle, are each attached to a different commutator hook, for example commutator hook 1a and 13a respectively, as a result of which two coils of the same set can always be formed at the same time. The final result, a winding having two or possibly more sets of coils, obviously remains the same.

Claims: Method for winding an armature body (56), provided with armature slots (101-124), of an armature (52) having a commutator (60) mounted on an armature shaft (58) and having commutator segments (1-24) provided with attachment elements (1a-24a), winding wire (200) being fed through the armature slots in accordance with a winding cycle and being attached to the attachment elements of the commutator segments to form a set of coils (201-224), the coils being electrically connected to one another via the commutator segments, characterized in that, after finishing the winding cycle mentioned, at least one additional winding cycle is carried out, winding wire again being fed through the armature slots already provided with coil sides of the coils of the set mentioned and being attached to the attachment elements of the commutator segments already connected to the coils of the set mentioned to form a further set of coils (225-248) electrically connected in parallel with the coils (201-224) of the first mentioned set. Method according to Claim 1, characterized in that the winding cycles mentioned are carried out immediately after each other, the winding wire (200) not being broken on passing from the one cycle to the other cycle. Method according to Claim 1 or 2, characterized in that the winding cycles mentioned are carried out in identical manners to each other. Electric machine provided with a stator (50) and an armature (52) produced by the method according to one of Claims 1, 2 or 3, characterized in that two coil sides of a first set of coils (201-224) electrically connected via a commutator and two coil sides of at least one further set of coils (225-248) electrically connected via the commutator (60) are present in each armature slot (101-124).

Inventors: VAN ASSEMA JOHAN CORNELIS, VAN ASSEMA, JOHAN CORNELIS
Applicants: PHILIPS NV, N.V. PHILIPS' GLOEILAMPENFABRIEKEN
Application year: 1990
Main classification: H02K15
IPC codes: H02K15, H02K23, H02K3