Patent GB-1143801-A (GB)
IPC: H02K33/16
Abstract: 1,143,801. Dynamo-electric machines. ELEKTRO-MOTOREN A.G. 9 March, 1966 [10 March, 1965], No. 10241/66. Heading H2A. The permanently magnetized rotor or longitudinally moving member of an electric motor or generator is made long and thin to reduce inertia, and the poles are made of sheet metal bent to extend round the air-gap. The moving member is at least five times as long as it is thick, and preferably ten times. In the rotary form shown in Fig. 1, the stator poles are of folded sheet metal having shanks 56, 57, faces 54, 55, and are linked by sheet-metal frame portions 52, 53 pushed together. As shown, the rotor-space 60 is displaced from the central position. This displacement may be taken to its extreme (Figs. 2 and 3, not shown) by having one salient pole only and using the curved surface of the other frame portion as the other pole-face. For higher pole-numbers, e.g. for polyphase working, the salient poles may be of double-T or Z-shape arranged round inside a sleeve or helix (Figs. 4-8, not shown). The permanent magnet rotor 76, Fig. 9, suitable for these stators is carried by shaft 77 in non- magnetic bearing bodies 78. These bearings have a narrow portion 79 which is pressed into the rotor space between the pole-faces and so located accurately in position. The larger part of the bearing body is hollow and contains lubricant. The rotor may be of metal alloy or ferrite. An alternative stator construction is shown in Fig. 12, in which four U-shaped polemembers 86, 87 which are supported on a non- magnetic carrier (85, not shown) are excited by a single-phase coil in the spaces within the arms of the members 86, 87. Magnetic return is provided by a surrounding tube, axially slit to prevent parasitic currents. The rotor is magnetized as two mutually diplaced, fourpole sections. This machine may be constructed in higher pole-numbers. The machine may be arranged for rotary oscillation by the use of buffer springs 105, e.g. as shown in Fig. 21, in which a dry-shaver cutter 113 acts against a foil 114, directly as shown, or through gearing. The magnet may be axially divided into two oppositely rotating sections. The machine may be rendered self-starting by the use of two radially magnetized rotor parts 120, 121 as shown in Fig. 23. The main part 121 is free on the shaft but is linked to the other part by a lost-motion abutment 125. This abutment engages freely in a slot 126 in the main part, this slot being padded on its impact surfaces. One pad is soft and springy, e.g. of rubber, while the other is hard, e.g. nylon. Due to this unequal resilience, the impact is greater in one direction than the other and so the motor starts up in this direction. Various other resilient, lost-motion links between the two rotors are described. A linear oscillating form is shown in Fig. 35, having a series of rolled-up interdigitated teeth 169, 170, through which a long, magnetized rod passes. If desired, there may be such teeth on both sides of the magnetizing coil 165. These bodies may oscillate in or out of phase. The linear stator may be a modification of the form shown in Fig. 12, as is shown in Fig. 12. Here there are two comblike rows of curved teeth 202, 203 extending from ribs 204, 205 lying within the coil, not shown. The armature is magnetized as shown in Fig. 40 and is carried on a bearing disc having a square role 211 by means of which it may be turned to a position of greater or less magnetic activity. Other arrangements for energizing the teeth are described, and these teeth and the magnetization pattern on the armature may be curved (Figs. 46, 47, not shown). The two types of machine may be combined to produce both linear and rotary motion at once.