DE3202074A1 - Permanent-magnet energised central rotary coupling - Google Patents

Abstract

The invention relates to a permanent-magnet energised central rotary coupling, in which the permanent magnets are preferentially oriented axially and are magnetised alternately in one axial direction and the other.

Description

Permanent Magnetically Excited Central Rotary Coupling The invention relates to a permanently magnetically excited central rotary coupling.

With permanently magnetically excited clutches, forces and ration occupancy Torques can be transmitted synchronously without contact. There are such clutches suitable for forces and torque through non-magnetizable walls in completely enclosed To transfer rooms into it.

\\ - while the permanent magnets move in known rotary couplings face each other with their end faces, the permanent magnets are in a central rotary coupling arranged coaxially at a distance from one another (air gap). In both cases, synchronous Torques generated by the fact that unlike magnetized permanent magnets attract each other and resistance to shearing tongues. The generated shear force multiplied with the mean diameter of the magnet arrangement is the measure of the torque.

In the case of central rotary couplings, the outer ring has the same number of pole pairs like the inner ring or the inner disk. With previously known Central rotary couplings are made of isotropic oxerite material in a ring shape.

Ferrite rings are inexpensive to manufacture. However, that is with isotropic ferrite rings due to the low energy product this group of materials is relatively low. One could, of course, like this be hysteresis clutches was proposed (DE-DS 19 42 534), a majority of clutches in axial Line up direction to increase torque. This multiple arrangement of magnets is limited by technological conditions. Rising axial Lengths lead to bending, to manufacturing tolerance problems and, above all, to high moments of inertia, which reduce the dynarnik of the clutches so much that they don't make sense of a bar. As radially preferential rings can be used at present State of the art ferritic materials will not be produced economically. The preferred radial direction creates tensions in the compact that occur during sintering cause the rings to tear. Accordingly, the reject is in the case of radially preferential directions Rings made of ferrite material are relatively high.

It is already known to use anisotropic materials (barium, lead, Strontium ferrite or rare earth nobalt, especially samarium cobalt) in the form individual blocks that are used in soft iron rings for central rotary couplings to use. However, this construction is considerably more expensive.

The Alagnete must be ground and the recesses in the soft iron rings be precision machined.

The object of the invention is to provide a permanent magnet arrangement in central rotary couplings to create that the use of anisotropic materials without great manufacturing effort and scrap enabled.

According to the invention this object is achieved in that the permanent magnets ax £ al-preferentially and alternately multipolar in one and the other axial direction are magnetized.

In the case of the central rotary coupling designed according to the invention, this results the advantage that the permanent magnets are ring-shaped with the preferred axial direction of the M-.gnetisierung can be produced by pressing and sintering without changing the preferred direction the risk of uneven shrinkage with the consequence that the rings will tear exists, as is the case with a radial preferred direction, g of the magnetization. at annular design of the permanent magnets has the further advantage that special Recordings for the magnets, which have to be precisely processed, are omitted.

According to an advantageous embodiment of the central rotary coupling according to the invention however, it is also possible to make the permanent magnets rod-shaped and not use ferromagnetic material, especially plastic.

The permanent magnet rods can be inserted into undersized axial bores be pressed into plastic rings. This design, which is also inexpensive is because they only have an injection-molded plastic ring or disk as a receiving element for which permanent magnets requires, offers several advantages. Magnet arrangements of this Art can do without special soft iron mountings. By inserting in or Overmoulding with non-ferromagnetic material License Uie permanent magnets against aggressive Aledians. be completely protected.

The elimination of soft iron backbacks still has the advantage that the moments of inertia are reduced, so that the starting properties of such Couplings are improved. Due to the inventive design of the permanent magnets there are no axial forces, rather the concentrically running ones are centered Rings in each other. An axial stringing together of several magnets with alternating Magnetization increases this effect. Possible technological demands, these To reduce the centering effect (compensation of mechanical tolerances in the overall structure of the system), can be realized that the magnet height between the outer and inner rings is different and that between the individual rings is not magnetizable intermediate layers are introduced or air is left.

The permanent magnet material is anisotropic barium, lead or strontium ferrite, but also Alnico or rare earth cobalt alloys, such as samarium cobalt, in Consideration.

The axially preferential magnetic rings are with the required The spacing is arranged concentrically and the outer and inner rings are matched to the Distance-optimized number of pole pairs axially magnetized. By known magnetizing devices for a segment-wise axial magnetization, except for the minimum winding space the magnetizing heads utilize the optimum magnet volume.

In the case of the construction of the central rotary coupling according to the invention, it is not as with known ones, the radial magnetic field but the axial magnetic field for generating the moment utilized. Since the most favorable material utilization and thus the greatest possible Torque per installation space in dynamic applications on the air gap between Inner and outer ring can be calculated with an optimized magnet length Magnet pair arrangement with the most favorable material utilization the maximum possible moments generated.

An increase in the torque can be achieved by having several Rings of the same type are layered on top of one another in the axial direction. that poles of the same name are adjacent to each other.

Exemplary embodiments of the invention are shown in the drawing.

FIG. 1 shows a view and FIG. 2 shows a cross section of an embodiment the magnet arrangement in a central rotary coupling, Figure 3 is a section through a Another exemplary embodiment and FIGS. 4-6 permanent magnets in a multiple arrangement.

In the embodiment according to FIGS. 1 and 2, there is a permanent magnet outer ring 1 arranged coaxially to the permanent magnet inner ring 2. Both permanent magnets 1 2 are axially multi-pole magnetized in the preferred position, as indicated by the letters N, S. is. In this embodiment according to FIGS. 1 and 2, neither recording elements are nor Pole pieces provided.

In the embodiment according to FIG. 3, the permanent magnets 1 ', 2' are rod-shaped and axially magnetized. In the outer ring, the permanent magnet rods 1 'are not ferromagnetic Material 3, e.g. B. plastic, injected. The inner ring made of plastic has axial bores 4, into which the permanent magnet rods 2 'are pressed.

According to FIGS. 4-6, permanent magnets can be arranged in multiple axial positions Direction be layered, with the individual rings with poles of the same name lying against one another. According to FIGS. 5 and 6, axial distances between the permanent magnets can also be used be provided, and the axial length of the permanent magnets 1 of the outer ring can be greater than that of the inner ring.

Claims (8)

Claim l.D magnetically excited central rotary coupling, thereby characterized, d-- 3 the permanent magnets (1, 2) axially preferential and alternating are magnetized in one and the other axial direction. 2. Central rotary coupling according to claim 1, characterized in that the permanent magnet (1) is a ring and the permanent magnet (2) is a ring or disk is. 3. Central rotary coupling according to claim 1, characterized in that axially magnetized permanent magnet rods (1 ', 2') in non-ferromagnetic WI material (3) are used. 4. Central rotary coupling according to claim 3, characterized in that the permanent magnet rods (1 ', 2') in undersized axial bores (4) in Plastic rings (3) are pressed in. 5. Central rotary coupling according to claim 3, characterized in that the permanent magnet rods (1 ', 2') with non-ferromagnetic material (3; overmolded are. 6. Central rotary coupling according to claims 1 to 5, characterized in that that several permanent magnets (1,2) in the axial direction with alternating ItIagnetisierungsrichtung are layered (Figs. 4 to 6). 7. Central rotary coupling according to claim 6, characterized in that the lengths of the inner and outer magnets (2 or 1) are different. 8. Central rotary coupling according to claim 6 and 7, characterized in that that between the axially lined up inner and outer magnets (2 or 1) Interstices are provided with air or non-magnetizable material are filled in (Fig. fi).