DE2929095A1 - HYSTERESIS CLUTCH - Google Patents

Description

ZAHNRADFABRIK FRIEDRICHSHAFEN - Aktiengesellschaft -

7990 Friedrichshafen

if hysteresis coupling

File: 5623 130008/003 7

ORIGINAL INSPECTlD

ZAHNRADFABRIK FRIEDRICHSHAFEN - Aktiengesellschaft -

7990 Friedrichshafen

Title; Hysteresis coupling

The invention relates to a hysteresis clutch, in particular for cooling fans in motor vehicle engines according to the preamble of claim 1.

Cooling fans are and are only rarely required in unusual operating conditions, particularly in motor vehicle engines then switched on or off via clutches. To switch the cooling fan on and off, it is known to be simple, electromagnetic to use switched clutches. With these clutches, the fan is also activated at very high speeds if required switched on, which causes very loud noises and reduces performance. These clutches are in yours too Torque not adjustable.

Furthermore, there are torque-limited (hysteresis) slip clutches known (see the article "permanent magnet! see clutches" in TEW Technical Reports 2, 1962, pages 153 to 159), with an excitation part and a hysteresis part, the excitation part having a permanent magnet and the hysteresis part a hysteresis disc arranged parallel to the exciter part consists. The axially parallel arrangement of the parts results in axial forces which stress the bearing. At this known hysteresis coupling, there is a constant power loss, associated with high heating. She is also in Torque cannot be regulated and cannot be switched off.

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The object of the invention is to specify a coupling, in particular for a cooling fan, which is silent works, has a minimal power loss, the torque of which can be regulated and completely switched off does not generate any axial forces and has minimal heating.

This object is achieved according to the invention with a coupling having the features of claim 1.

The clutch according to the invention is a slip clutch which operates on the principle of the hysteresis clutch is constructed, so has an excitation part and a hysteresis part as input and output elements. These are arranged without contact, but close to each other, whereby the exciter part rotates and rotates with each other has displaceably connected rows of pronounced poles of the same number, offset by half a division are arranged to each other. The hysteresis part is rotatably provided between these two rows of poles. The magnetic flux is forced by the offset of the poles by half a pitch, in which between the The hysteresis part located in the rows of poles is essentially tangential, but changes from pole to pole Direction to take, and thereby to magnetize sub-districts in the opposite direction. When turning one coupling part a reversal of the magnetization of the partial areas is inevitable, which causes a torque.

It is particularly advantageous that the exciter part is an electromagnet which consists of a soft magnetic yoke with an exciter coil. The height Field strength of an electromagnet allows the use

Generation of a hysteresis part with high magnetic reversal energy, which guarantees a high torque. Also is according to the invention, the current consumption of the excitation coil is variable, for example by a temperature

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dependent series resistance, whereby a stepless Torque control is achieved.

According to the invention, the number of poles of the exciter part can be selected very high by fine division of the soft iron poles, which has the advantage of a relatively high Torque brings with it.

According to the invention, a particularly good result was achieved obtained in that the pole width is about twice the ring thickness and the pole pitch about four to five times the ring thickness has been selected.

According to a further development of the inventive concept, the two rows of poles of the exciter part and the hysteresis part are essentially disc-shaped, it being possible to speak of two pole discs W connected to one another and a hysteresis disc lying between them.
20th

According to another development of the concept of the invention the two rows of poles of the excitation part and the hysteresis part are essentially annular and arranged concentrically to one another, two of which are connected to one another in a rotationally and displaceably fixed manner Pole rings and a hysteresis ring arranged between these two and rotatably arranged relative to them can be. This annular arrangement has the advantage that the hysteresis ring is radial

is carried out, whereby no axial forces occur and whereby the radial forces cancel each other out. Due to the offset poles of the pole rings, a tangential flow direction is forced, which parts of the hysteresis ring in the opposite direction

premagnetize the device. When the hysteresis ring rotates in relation to the polarized rotor, a reaction force arises against magnetization reversal. This force is independent of the rotational speed and on

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equally effective at every point. The umagnetization of the entire volume of the hysteresis ring takes place as often as there are poles in one revolution as a run through the hysteresis loop of the used Permanent magnet material.

The hysteresis coupling according to the invention can be used as a coupling for motor vehicle cooling fans and with corresponding Changes can be used as a brake with slip control.

Further features of the coupling according to the invention are set out below in connection with that in the drawings illustrated embodiment explained. 15th

In the drawing show:

Fig. 1 is a partial, axial section through a coupling according to the invention in ring

shaped design,

FIG. 2 shows a section II-II from FIG. 1, the according to the invention Showing the arrangement of the rows of poles, and

FIG. 3 shows a development of part of the pole rows shown in FIG.

The hysteresis coupling according to the invention consists essentially of one arranged on a bobbin 14 Electromagnet coil 13, which is attached to a housing part 16 .. In this housing part

16, a shaft 17 is rotatable via a bearing 15 and axially immovable. On the shaft 17: a rotor 9 is fixed, which on its outer circumference has a baffle 11 which extends the circumference

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of the bobbin 14 partially encloses and on which a pulley 10 is provided. The rotor 9 represents the soft magnetic yoke of the excitation coil 13 dar / and has two concentric to each other Rows of poles, an inner row of poles 7 and an outer row of poles 8, which have the same pole pitch 20, The poles of the two rows of poles are each half a pole pitch 20 in a tangential direction to one another postponed. In order to allow the magnetic flux 2 to flow in a targeted manner only through the pole parts, the is axially the coil 13 facing part of the rotor 9, a magnetic insulation 12 is provided. Between the two rows of poles a hysteresis ring 3 is arranged, the inner and outer surfaces of which are very close to the pole surfaces, however, do not touch them. The hysteresis ring 3 is rotatably and displaceably arranged in a mounting flange 4, which in turn has a Bearing 18 rotatable on shaft 17, but axially immovable is stored. A fan 5 is attached to the Aufnahraeflansch 4 via a screw 1. When switched on Coil, the magnetic flux 2 in the rotor 9 will run essentially radially inward, with due to the staggered formation of the rows of poles, the magnetic flux as it passes through the Poles in the hysteresis ring have a substantial tangential course. One can assume that at each pole of the upper row of poles approximately half of the magnetic flux (see FIG. 3) is a left, tangential one Alignment gets while the other half

^ O of the magnetic flux a right, tangential orientation is obtained, as a result of which a region-wise reversal of magnetization 19 of the hysteresis ring 3 is obtained.

The clutch example explained can of course also be ^used with advantage in slip clutches for purposes other than driving a fan, preferably where a drive must be switched on silently over a large speed range

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and where a speed-independent reaction force is required for the transmission of the driving force to the output will.

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Claims (10)

ZAHNRADFABRIK FRIEDRICHSHAFEN - Aktiengesellschaft - 7990 Friedrichshafen Title: Hysteresis Clutch PATENT CLAIMS (1 J hysteresis (slip) clutch, especially for cooling air ^ ' ter in motor vehicle engines, with an exciter part and a hysteresis part (as input and output elements), which are arranged contactless, but close to one another, the exciter part having multiple polarities and the hysteresis part consists of a permanent magnet, which allows the hysteresis part to be reversed multiple times, characterized in that the exciter part is associated with two rotatably and displaceably fixed to one another Rings (7, 8) with pronounced, mutually offset poles of the same number, between which the hysteresis part (3) is rotatably guided. 2. Hysteresis clutch according to claim 1, characterized in that the exciter part has an electromagnet (13) with a has soft magnetic yoke (9) with excitation coil. 3. Hysteresis clutch according to one of claims 1 and 2, characterized by a close sequence of the soft iron poles, so that a number of poles is arranged on each ring. File 5623 - 2 - 130008/0037 4. Hysteresis clutch according to claim 1, characterized in that that the hysteresis part is made of hysteresis material with high magnetic reversal is. 5. hysteresis coupling according to claim 1, 2 and 3, characterized characterized in that the current consumption of the excitation coil is variable. 6. hysteresis clutch according to claim 1, characterized in that that the pole width is about twice the thickness of the hysteresis ring. 7. hysteresis clutch according to claim 1 and 6, characterized characterized in that the pole pitch is preferably about four to five times the thickness of the hysteresis ring amounts to. 8. hysteresis clutch according to one or more of claims 1 to 7, characterized in that the both pole rows of the exciter part and the hysteresis part are essentially disk-shaped are and are arranged axially offset from one another. 9. hysteresis clutch according to one or more of claims 1 to 7, characterized in that the both pole rows of the exciter part and the hysteresis part are essentially ring-shaped and are arranged concentrically to one another. 30th 10. hysteresis clutch according to claim 1 and further, characterized in that the excitation part represents the drive side during the hysteresis part the output side is.
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