DD156109A1 - ELECTRODYNAMICALLY IMPROVED STEPPER MOTOR - Google Patents

Abstract

The invention relates to an electrodynamically damped stepping motor, in particular with permanently excited rotor. The arrangement for Bedaempfen the rotor movement should be able to be produced with a small effort, ensure a long service life and be optimized according to the operating characteristic. The object has been achieved by the fact that the rotor has magnetic zones of alternating polarity on one end side, which interact with a reaction disk fixedly arranged in the stator. The stepper motor according to the invention is used in particular for digital information processing for positioning and positioning tasks.

Description

Title of the invention. ''. Electrodynamically vaporized stepper motor

Field of application of the invention

The invention "refers to a stepper motor with an electrodynamic arrangement for damping the rotor movement, in particular for stepper motors with permanently excited rotor.

Characteristic of the known technical solutions

Stepper motors have a discontinuously rotating rotor which rotates stepwise in response to the pulses applied to the working coil, with the rotor coming to a standstill after each step. For safe operation, it is necessary for the motor to accurately perform each step within its operating parameters. In order to achieve high high frequencies and torques, one is. Attenuation of the electromechanical system required. For this purpose, various arrangements have become known. "Mach the DT-AS 1 488 654 and DT-OS 2,108,001, .IPK H 02 K, 37/00, the damping is achieved in that the housing of the stepping motor with liquid of a bestimm.Viskosität is filled, with which the rotational movement of the rotor is damped by! Fluid friction. A similar proposal is made in DD-AP 59 311, DPK 21 d ¹ , 19, according to which the stepper motor is also filled with fluid or coupled to a fluid-filled rotation system

The disadvantages of such arrangements for damping step

In particular, there are technological problems in the production of liquid-tight housings and in the need for constant operating temperatures, since the viscosity of the liquids and thus their damping properties change with temperature.

Further arrangements for damping the electromechanical system of stepping motors provide, as described in DT-OS 1 538 962, freely rotatable additional flywheel masses on the rotor, which are coupled to the rotor by mechanical friction or plunger couplings The production costs for such arrangements are very high high.

According to DT-OS 2,136,531, IPK H 02 K, 37/00, a layer of electrically highly conductive material is arranged on the rotor of a stepping motor. In this layer eddy currents are induced by the working flow, which have a dampening effect on the rotor movement. The eddy currents induced in this layer therefore act only in the time in which there is a working flow. At the same time occurs as a disadvantage, a damping of the work flow and thus a deterioration in efficiency.

Finally, it is known according to DD-AP 59 311 to steam rotors by mechanical friction. The friction torque, which is practically independent of the rotational speed, adversely affects the startup performance of the stepper motors and limits their service life. "

In the same patent the damping of stepper motors by eddy current braking is described. In this case, a copper disc rotates in the electromagnetic field and causes a rotational speed-proportional damping. However, the necessary for the required attenuation of the size of the eddy current damper influences the moment of inertia of the stepping motor considerably and is difficult to arrange especially for small sizes.

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Target of the Exfindunc;

The object of the invention is to reduce the production of it and to improve the efficiency of the electrodynamic "vaporized stepper motors".

Explanation of the nature of the invention

The invention has for its object to provide a elektrodynamisch "steamed stepper motor with an electrically excited pole having stator and a particular permanent-magnet rotor with circumferentially arranged poles, which contains a rotational speed proportional acting, easy to produce electrodynamic damping, with a high efficiency, and At the same time, the mass moment of inertia of the rotating system should not be increased as much as possible.

The object of the invention is achieved in that the rotor has magnetic zones of alternating polarity at least on one end face and is arranged rotatably in the stator, separated from the rotor by an axial air gap, by an electrically or electrically and magnetically conductive reaction disk.

To reduce the production costs, the reaction disk is expediently designed as a part of the motor housing. The design of the reaction disk of electrically conductive soft magnetic material identical to the motor housing is advantageous,

In this simplest. Embodiment of the invention v / eist the damped stepper motor with respect to the undamped no, additional component, since the functional elements of the damping device are integrated into the construction elements of the stepping motor. "As an additional expense, only the magnetization to be made on the front side of the rotor is required.

The vortex currents induced in the electrically conductive, soft-magnetic reaction disc generate a torque, whereby the required amount of induction is achieved by simultaneously ensuring the low magnetic resistance required for conducting a high magnetic flux.

The axial tensile forces that occur between the rotor and the reaction disk, in cooperation with a spacer ensure the required for a reproducible damping constant air gap without high loleranzforderungen for axial bearing clearance or other equivalent structural measures would be required.

In order to adapt the damping characteristic to the operating characteristic of the stepping motor and at the same time to optimize the axial Xagerkräfte the reaction disc in one embodiment of the invention consists of two layers, of which the rotor facing layer of electrically conductive non-magnetic material and the rotor facing away from the layer of soft magnetic material.

In a particular embodiment, the electrically conductive non-magnetic layer is 30-70 $ of the total thickness of the reaction disc, wherein the soft magnetic layer is designed not thicker than required for flux conduction.

While in the embodiment of the reaction disc made of electrically conductive soft magnetic material is a proportional constant relationship between the generated by eddy currents damping torque (based on a constant rotational speed) and the axial tensile force can, in a reaction disc of two layers as described above, the damping torque within wide limits be selected independently of the axial tensile force. As a result, despite a possible increase in the damping torque, the axial bearing load is substantially reduced and it can

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Life of the stepper motor can be increased.

Is there a permanent magnet for the rotor of the stepper motor?

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very high field strengths, e.g. greater than 1500 A cm available s is sufficient for the reaction disc an electrically conductive non-magnetic material. In this Pail, since there are no axial tensile forces, other constructive measures must be taken to achieve a constant air gap.

embodiment

The invention will be explained below with reference to an embodiment v / earth »Show in the accompanying drawings

Pig. 1 is a perspective view of a permanent-magnet rotor

Pig. 2 a half section through the

Stepper motor according to the invention

The one in Pig. Rotor 1 shown 1 consists of a mounted on a shaft 2 cylindrical magnetic body, on the periphery of sixteen poles 3 and an.einer end face four magnetized zones 4 alternating pole sequence are arranged.

In Pig. 2 is such after Pig. 1 magnetized rotor 1 arranged in the stator of a stepping motor. The stator has two interconnected, made of weichmagnetischein deep drawn inner housing shells 5 and 5 ', each with eight claw poles 6 and 6 ^! on, many in two outer housing shells 7 and 7 ^{ are arranged from the same material o The outer housing shells 7 and 7 'have eight Kla, uenpole 8 and 8', which are located in the middle between the two claw poles or 6 'are located.

The claw poles 6 or 6 ^f and 8 or * 8 ^! are shifted against each other by half Klauenpölteilung. Within the housing sha.len 5 and .. 5 'and 7 or 7' are-on bobbins. 9

 and 9 ', the working windings 10 and 10' are arranged. In the outer housing shells T and 7 ', the bearings 11 and 11 · are arranged for the shaft 2 of the rotor 1. The adjoining the bearing 11 annular zone 12 of an outer housing shell 7 is rotatably connected to an aluminum disc 13. The annular zone 12 and the aluminum slab 13 together form the reaction slit interacting with the magnetizing zones 4 of the end face 14 of the rotor 1. To secure a constant axial air gap 15, a spacer 16 is disposed between the bearing 11 and the end face 14 of the rotor 1, which consists of a sliding material.

The thickness ratio between the deep-drawn sheet in the annular zone 12 and the aluminum disk 13 is selected 1: 1, resulting in an optimally tuned operating characteristic for the given stepper motor.

Claims (5)

6% 6ψ β , A pulsed stepper motor with an electrically energized pole and a particular permanent magnet rotor with circumferentially arranged poles, characterized in that the rotor (1) has magnetic zones of alternating polarity at least at one end and parallel to it in the stator an axial-air gap separated from the rotor, an electrically or electrically and magnetically conductive reaction disc is arranged rotationally fixed. 2. Electrodynamically steamed stepping motor according to item 1, characterized in that the reaction disc is a part of the motor housing. 3. Electrodynamically steamed stepping motor according to item 1 or 2, characterized in that the reaction disc consists of electrically conductive soft magnetic material. 4. Electrodynamically steamed stepper motor according to item 1 or 2, characterized in that the reaction disc has two layers, of which the rotor facing layer of electrically conductive non-magnetic material and the rotor facing away from the layer of soft magnetic material. 5. Electrodynamically vapor-pulsed stepper motor according to item 1 and A or 2 and 4, characterized in that the layer of electrically conductive non-magnetic material 30 - 70 ^ the total thickness of the reaction disk is, wherein the soft magnetic layer is designed to be thicker than required for KL-line, 6a Elelctrodynamisch steamed stepping motor according to item 1 or 2, characterized in that the reaction disc consists of electrically conductive material.