Title of Invention

METHOD OF FITTING A WORM TO AN ARMATURE SHAFT OF AN ARMATURE OF AN ELECTRIC MOTOR, AND ARMATURE PRODUCED WITH THIS METHOD

Abstract

The invention relates to a method for fitting a worm (30) to an armature shaft (12) of an armature (10) for an electromotor. According to this method, armature parts such as a laminated armature core (18) with armature windings (20), a commutator (14), a bearing seat (26) and/or a bearing (28) are fitted to the armature shaft (12) first and the worm (30) is then rolled on the armature shaft (12). This has the advantage that the worm (30) can have a larger diameter than the armature shaft (12) over its remaining length of the latter.

Full Text

Method of fitting a worm to an armature shaft of me immature of an electric motor, euid armature produced with this method Description Prior art The invention relates to a method of fitting a worm to an armature shaft of an armature of an electric motor, and to an armature produced with the method. It is known to produce a worm in one piece with the armature shaft by shaping, in particular by rolling an armature shaft of an electric motor. The armature is then assembled from its individual parts, that is to say, for example, a laminated armature core, a commutator and bearings are put onto the armature shaft. The laminated armature core may already be provided with armature windings when it is put onto the armature shaft, or the armature windings are wound onto the laminated armature core pu^ onto the armature shaft. In order to be able to put the individual parts of the armature onto the armature shaft, an external diameter of the worm produced on the armature shaft by shaping must not be greater than a diameter of the armature shaft over the remaining length of the armature shaft. This has the disadvantage that an armature shaft with a large diameter is necessary or the worm has a small diameter, which limits a load bearing force and a thread pitch of the worm. Another possibility is to produce the worm as a separate part, to put it onto the armature shaft and to connect it to the armature shaft so that it rotates with the latter. This has the disadvantage of a higher outlay, and there may be an alignment error between the armature shaft and worm. Advantages of the invention In the method according to the invention, having the features of Claim 1, first of all the armature is assembled from its individual parts, that is to say, for example, the laminated armature core, the commutator and sliding and/or rolling bearings are put onto the armature shaft, and the worm is subsequently produced by shaping the armature shaft. This makes it possible to produce the worm with a greater diameter than the remainder of the armature shaft, since the individual parts of the armature do not have to be put onto the armature shaft over the worm. For the purpose of shaping, the armature shaft can be held at its bearings or bearing points. The invention has the advantage that a simple and cost-effective armature shaft without steps can be used, i.e. the armature shaft may be produced from a rod which has no change in cross section over its entire length, that is to say, for exaitjple, from inexpensive bar material. Moreover, the invention permits a small diameter of the armature shaft, as a result of which the overall size and the weight of the armature, and therefore the overall size and weight of the entire electric motor, are reduced. As a result of the reduced weight and the reduced diameter of the armature, its rotational moment of inertia is reduced, and this improves the starting behaviour of the electric motor. As a result of its greater core diameter, the worm produced in accordance with the invention has a higher strength. As a result of the single-piece production of the worm with the armature shaft, an alignment error is small. Advantageous refinements and developments of the invention specified in the main claim are the subject of the subclaims. According to Claim 2, the worm is preferably produced by rolling. According to Claim 3, before the production of the worm, a tubular bearing seat is fitted in between armature parts put onto the armature shaft, that is to say, for example, the laminated armature core and the commutator, and the worm which is yet to be produced. The tubular bearing seat can, for example, be pressed or shrunk onto the armature shaft, the latter meaning that the bearing seat is heated and, as a result, its diameter is increased and consequently easily pushed onto the armature shaft, on which, following cooling, it is rotationally fixedly and immovably seated. The bearing seat makes it possible to widen the diameter of the armature shaft in the area of the bearing to at least the external diameter of the worm, without having to use a stepped armature shaft for this purpose. The greater diameter at the bearing seat of the armature shaft permits the fitting of a shaft bearing after the worm has been produced by shaping. This has the advantage that a cooling lubricant used during the shaping of the worm or dirt particles produced during the shaping of the worm do not get into the shaft bearing, and that, following the shaping of the worm, the armature can be cleaned without difficulty, for example even using a rinsing solution. According to Claim -4, the bearing arranged between the laminated armature core and the commutator, on the one hand, and the worm, on the other hand, can be put directly onto the armature shaft without a separate bearing seat and before the shaping of the worm. This has the advantage that a separate bearing seat and its assembly are dispensed with, and that all the parts to be put onto the armature shaft are put onto the armature shaft before the shaping of the worm. The production of the armature ends with the shaping of the worm, and it is not necessary for the bearing to be put onto the shaft subsequently. Accordingly the present invention provides a method of fitting a worm to an armature shaft of an armature of an electric motor, characterized in that the worm is produced by shaping the armature shaft at the end of the assembly of the armature from its individual parts. Accordingly the present invention also provides an armature produced in accordance with the method as hereinabove described for an electric motor, having an armature shaft which has a worm which is in one piece with the armature shaft, wherein that the worm has a greater external diameter than the armature shaft over the remaining length of the latter. Drawing ■ ■ The invention will be explained in mo:ire detail below using two exemplary embodiments illustrated in the drawing. The two figures show two armatures produced in accordance with the invention in half-section. Description of the exemplary embodiment The armature 10 illustrated in Figure 1 and produced in accordance with the invention has an armature shaft 12 which is produced from a cylindrical material which has no changes of diameter or cross section over its length. The armature shaft 12 can, for example, be divided off from cylindrical bar material. According to the invention, first of all individual parts of the armature 10, a commutator 14 and a laminated armature core 18 encapsulated in plastic 16 in the exemplary embodiment illustrated, are put onto the armature shaft 12 such that they rotate with it. The laminated armature core 18 bears armature windings 20, which are wound onto the laminated armature core 18 before or after the laminated armature core 18 is put onto the armature shaft 12. At the commutator 14, contact is made in a manner -known per se with ends 22 of the armature windings 20. On a side of the laminated armature core 18 facing away from the commutator 14, the armature shaft 12 protrudes a little from the laminated armature core 18 and the armature windings 20. This end of the armature shaft 12 forms a bearing seat 24 for a sliding bearing (not illustrated). On the other side, the armature shaft 12 projects by a greater length from the commutator 14. On this side, a tubular bearing seat 26 for a rolling-contact bearing 28 or a sliding bearing (not illustrated) is pressed or shrunk onto the armature shaft 12 such that it is rotationally fixed and axially immovable. Following the fitting of the commutator 14, the laminated armature core 18 with the armature windings 20, and the bearing seat 26 to the armature shaft 12, its end protruding from the bearing seat 26 is shaped by rolling to form a worm 30. During the rolling of the worm 30, the armature 10 can be mounted at its two bearing seats 24, 26. The worm 30 has a greater external diameter than the armature shaft 12 over the remaining length of the latter outside the worm 30. As a result of shaping the worm 3 0 following the fitting of the laminated armature core 18 with the armature windings 20 and the commutator 14 to the armature shaft 12, the worm 30 can be produced with a greater diameter than the armature shaft 12 over the remaining length of the latter, since the aforementioned parts 18, 20, 14 of the armature 10 do not have to be pushed over the worm 30. The bearing seat 26 put onto the armature shaft 12 between the commutator 14 and the worm 30 has an external diameter which is at least as large as the worm 30, so that the ball bearing 28 or a sliding bearing (not illustrated) can be put onto the bearing seat 26 after the rolling of the worm 30 and any possible cleaning of the armature. In the case of the armature illustrated in Figure 2, the bearing seat- 26 arranged between the commutator 14 and the wo2rm 3 0 has been left out, and the ball bearing 28 or the sliding bearing (not illustrated) is put onto the armature shaft 12 directly and before the rolling of the worm 30. The ball bearing 28 or the sliding bearing (not illustrated) can be used for mounting the armature 10 during the rolling of the worm 30. The ball or sliding bearing 28 is covered, if necessary, for the purpose of rolling the worm 30. WE CLAIM: 1. A method of fitting a worm to an armature shaft of an armature of an electric motor, characterized in that the worm (30) is produced by shaping the armature shaft (12) at the end of the assembly of the armature (10) from its individual parts (12, 14, 18,20 26). 2. The method as claimed in claim 1, wherein the worm (30) is produced by rolling. 3. The method as claimed in claim 1, wherein before production of the worm (30), a tubular bearing seat (26) is fitted to the armature shaft (12), between individual parts (14, 18, 20) of the armature (10) put onto the armature shaft (12) and the worm (30) to be produced, an external diameter of the bearing seat (26) being at least as large as an external diameter of the worm (30) to be produced. 4. The method as claimed in claim 1 wherein before production of the worm (30), a shaft bearing (28) is fitted to the armature shaft (12), between individual parts (14, 18, 20) of the armature (10) put onto the armature shaft (12) and the worm (30) to be produced. 5. An armature produced in accordance with the method as claimed in any one of claims 1 to 4 for an electric motor, having an armature shaft which has a worm which is in one piece with the armature shaft, wherein that the worm (30) has a greater external diameter than the armature shaft (12) over the remaining length of the latter. 6. The armature as claimed in claim 5, wherein the armature shaft (12), between the worm (30) and individual parts (14, 18, 20) of the armature (10) put onto the armature shaft (12), there is fitted a tubular bearing seat (26), whose external diameter is at least as large as an external diameter of the worm (30). 7. The armature as claimed in claim 5, wherein a shaft bearing (28) is fitted directly to the armature shaft (12), between the worm (30) and individual parts (14, 18, 20) of the armature (10) put onto the armature shaft (12). 8. A method of fitting a worm to an armature shaft of an armature of an electric motor, substantially as herein described with reference to the accompanying drawings. 9. An armature, substantially as herein described with reference to the accompanying drawings.

Documents:

in-pct-2000-814-che abstract.jpg

in-pct-2000-814-che abstract.pdf

in-pct-2000-814-che claims-duplicate.pdf

in-pct-2000-814-che claims.pdf

in-pct-2000-814-che correspondence-others.pdf

in-pct-2000-814-che correspondence-po.pdf

in-pct-2000-814-che description(complete).pdf

in-pct-2000-814-che descrtiption(complet)-duplicate.pdf

in-pct-2000-814-che drawings.pdf

in-pct-2000-814-che form-1.pdf

in-pct-2000-814-che form-19.pdf

in-pct-2000-814-che form-26.pdf

in-pct-2000-814-che form-3.pdf

in-pct-2000-814-che form-5.pdf

in-pct-2000-814-che others.pdf

in-pct-2000-814-che petition.pdf