TRANSDUCER ASSEMBLY FOR A TORQUE AND/OR ANGLE SENSOR

Abstract

A transducer assembly for a torque and/or angle sensor may comprise a pipe section-shaped magnet ring that is secured to a carrier sleeve via an intermediate element. The intermediate element and the magnet ring may be integrally bonded to one another via joining surfaces directed against one another. The intermediate element may be formed of a plastic at least in a region of its joining surface. To provide a transducer assembly that can be more easily produced and assembled with high reliability, the magnet ring may be formed as a plastic-bonded magnet from a plastic material filled with magnetic particles, which is integrally bonded to the plastic of the intermediate element.”

Claims

1.-12. (canceled)

13. A transducer assembly for a torque and/or angle sensor, the transducer assembly comprising a pipe section-shaped magnet ring configured as a plastic-bonded magnet comprising plastic material filled with magnetic particles, the pipe section-shaped magnet ring being secured to a carrier sleeve via an intermediate element, wherein a joining surface of the intermediate element that comprises plastic is integrally bonded to a joining surface of the pipe section-shaped magnet ring that comprises the plastic material filled with the magnetic particles.

14. The transducer assembly of claim 13 wherein the plastic of the intermediate element and the plastic material of the pipe section-shaped magnet ring are thermoplastic polymers that are compatible for purposes of forming an integrally bonded connection.

15. The transducer assembly of claim 13 wherein at least one of the intermediate element or the pipe section-shaped magnet ring is an injection molded part.

16. The transducer assembly of claim 13 wherein the pipe section-shaped magnet ring is a pressed part.

17. The transducer assembly of claim 13 wherein the plastic material of the pipe section-shaped magnet ring is highly filled with magnetic materials with a degree of filling between 80% to 97% in terms of weight.

18. The transducer assembly of claim 13 wherein the intermediate element and the pipe section-shaped magnet ring are welded.

19. The transducer assembly of claim 13 wherein the intermediate element and the pipe section-shaped magnet ring are ultrasound or laser welded.

20. The transducer assembly of claim 13 wherein glue holds the intermediate element and the pipe section-shaped magnet ring together.

21. The transducer assembly of claim 13 wherein the pipe section-shaped magnet ring is connected on a substantially axial end face to an axial end face of the intermediate element.

22. The transducer assembly of claim 13 wherein the carrier sleeve is configured as a pipe section and comprises a radially outward protruding fastening element in one end region.

23. The transducer assembly of claim 22 wherein the radially outward protruding fastening element is disposed axially in a form-fitting manner between opposing end faces of the pipe section-shaped magnet ring and the intermediate element.

24. The transducer assembly of claim 22 wherein the intermediate element is disposed axially between opposing end faces of the pipe section-shaped magnet ring and the fastening element.

25. A method of producing a transducer assembly for a torque and/or angle sensor, the transducer assembly comprising a pipe section-shaped magnet ring configured as a plastic-bonded magnet comprising plastic material filled with magnetic particles, the pipe section-shaped magnet ring being secured to a carrier sleeve via an intermediate element, wherein a joining surface of the intermediate element that comprises plastic is integrally bonded to a joining surface of the pipe section-shaped magnet ring that comprises the plastic material filled with the magnetic particles, the method comprising: providing the pipe section-shaped magnet ring configured as the plastic-bonded magnet; integrally bonding the pipe section-shaped magnet ring to the intermediate element that comprises plastic; and fastening the intermediate element to the carrier sleeve.

26. A transducer assembly for a torque and/or angle sensor comprising a pipe section-shaped magnet ring that is secured to a carrier sleeve via an intermediate element, wherein the intermediate element and the magnet ring are integrally bonded to one another via joining surfaces directed against one another, wherein the intermediate element is formed of a plastic at least in the region of the joining surface, wherein the magnet ring is formed as a plastic-bonded magnet from a plastic material filled with magnetic particles, which is integrally bonded to the plastic of the intermediate element.

27. The transducer assembly of claim 26 wherein the plastic of the intermediate element and the plastic material of the magnet ring are thermoplastic polymers that are compatible for purposes of forming an integrally bonded connection.

28. The transducer assembly of claim 26 wherein at least one of the intermediate element or the magnet ring is an injection molded part.

29. The transducer assembly of claim 26 wherein the magnet ring is a pressed part.

30. The transducer assembly of claim 26 wherein the plastic material of the magnet ring is highly filled with magnetic materials with a degree of filling between 80% to 97% in terms of weight.

31. The transducer assembly of claim 26 wherein the intermediate element and the magnet ring are welded.

32. The transducer assembly of claim 26 wherein the intermediate element and the magnet ring are ultrasound or laser welded.

Description

DESCRIPTION OF THE DRAWINGS

[0031] Advantageous embodiments of the invention shall be explained more closely below with the aid of the drawings. Specifically, there are shown:

[0032] FIG. 1: a transducer assembly according to the invention in perspective view,

[0033] FIG. 2: a longitudinal section through the transducer assembly per FIG. 1,

[0034] FIG. 3: an exploded view of the transducer assembly per FIG. 1,

[0035] FIG. 4: a longitudinal section as in FIG. 2 through the elements of the transducer assembly before mounting,

[0036] FIG. 5: a detail view of the cross-sectional representation of FIG. 2,

[0037] FIG. 6: a partial longitudinal section through a second embodiment of a transducer assembly according to the invention,

[0038] FIG. 7: a partial longitudinal section through a third embodiment of a transducer assembly according to the invention,

[0039] FIG. 8: a partial longitudinal section through a fourth embodiment of a transducer assembly according to the invention,

[0040] FIG. 9: a partial longitudinal section through a fifth embodiment of a transducer assembly according to the invention,

[0041] FIG. 10: a partial longitudinal section through a sixth embodiment of a transducer assembly according to the invention.

EMBODIMENTS OF THE INVENTION

[0042] In the different figures, the same parts are always provided with the same reference numbers and therefore as a rule they will only be designated or mentioned once.

[0043] FIG. 1 represents a transducer assembly 1 according to the invention in a perspective view obliquely to the longitudinal axis A. This is formed by a magnet ring 2 and a carrier sleeve 3, which is arranged on the magnet ring 2 via a substantially ring-shaped intermediate element 4.

[0044] The intermediate element 4 has a basic ring shape and comprises a joining surface 42 on its axial end face 41 directed against the magnet ring 2. The intermediate element 4 is made of plastic, preferably as an injection molded part made of a first thermoplastic plastic.

[0045] The magnet ring 2 has the basic shape of a cylindrical pipe section with an axial end face 21 directed against the intermediate element 4, on which a joining surface 22 is formed, corresponding to the joining surface 42 of the intermediate element 4. The magnet ring 1 is designed as a plastic-bonded magnet, made from a plastic material highly filled with magnetic powder. The plastic material is also preferably a thermoplastic plastic, in the plastic matrix of which the ferromagnetic magnetic particles of the magnetic powder are embedded.

[0046] According to the invention, the plastic material from which the intermediate element 4 is formed and the plastic material which forms the plastic matrix of the magnet ring 2 are compatible with each other in terms of an integrally bonded connection, here preferably a thermal welding. It is conceivable for the first and second plastic material to be formed from an identical polymer—such as polyamide (PA), polypropylene (PP), polyphenyl sulfide (PPS) or another—or at least from similar, compatible polymer materials enabling an integrally bonded connection in the melt for the thermal weldability, or which are compatible in terms of their surface properties in regard to an integrally bonded connection by means of an adhesive placed between the joining surfaces 22 and 42.

[0047] The carrier sleeve 3 has a cylindrical tubular base body made of metal, preferably steel, which is arranged with radial play coaxially inside the magnet ring 2 and comprising an encircling annular flange 31 projecting radially outward on its end facing the intermediate element 4, forming a fastening element of the carrier sleeve 3. The one axial end face 32 of the flange 31 is directed axially against the intermediate element 4, the other axial end face 33 toward the magnet ring 2. The flange 31 may comprise form-fitting elements 34, which in the example shown are formed as radial recesses in the outer circumference.

[0048] For the production of a transducer assembly 1, the magnet ring 2, the intermediate element 4 and the carrier sleeve 3 are provided and moved toward one another in the axial direction from the preliminary mounting position shown in FIGS. 3 and 4, with the flange 31 of the carrier sleeve 3 positioned axially between the magnet ring 2 and the intermediate element 4, as shown in FIG. 2.

[0049] As can be seen from the magnified representation in FIG. 5, the intermediate element 4 comprises an axial recess 43 radially inside the joining surface 42, in which the flange 31 of the carrier sleeve 3 is received, as shown. Thanks to an integrally bonded connection of the intermediate element 4 with the magnet ring 2 at the joining surfaces 22 and 42, a single composite piece is formed, with the flange 31 of the carrier sleeve 3 held by axial form-fit in the now axially covered recess 43. No integrally bonded or form-fitting connection is produced between the carrier sleeve 3 and the magnet ring 2, so that the transmission of mechanical stresses, such as those caused by different thermal expansion, from the metallic carrier sleeve 3 to the magnet ring 2 is precluded.

[0050] The integrally bonded connection between the joining surfaces 22 and 42 lying axially against one another can be produced by a thermal welding method, preferably by friction or ultrasound welding. For this, the magnet ring 2 is braced axially, while a welding punch 5, preferably a sonotrode 5 of an ultrasound welding kit, is pressed axially from the outside, i.e., from the free end face in the region of the joining surface 42, axially against the intermediate element 4, as shown by the arrow in FIG. 5. The joining surface 42 is hereby pressed against the corresponding joining surface 22 on the magnet ring 2 and vibrational energy is coupled in, by which the joining surfaces 22 and 42 are heated up and partly melted.

[0051] The joining surface 22 of the magnet ring 2 comprises an axially projecting protrusion 23, which in the embodiment depicted is fashioned as an encircling rib with knife-blade cross section. In this way, a welding material reservoir is provided, which is melted already at the start of the welding, when the protrusion 23 first makes contact with the joining surface 42. The fluid or at least viscous melted plastic is distributed in the joint gap between the joining surfaces 22 and 42, resulting in a diffusion or mixing of the plastic materials of the magnet ring 2 and the carrier sleeve 4 in the boundary surface region.

[0052] In the region of the joining surface 42 there can also be formed a form-fitting element 44 in the shape of an axially projecting, annular encircling rib. This can engage in a corresponding depression 24 in the joining surface 22. In this way, the intermediate element 4 can be positioned easily relative to the magnet ring 2.

[0053] After the end of the ultrasound excitation, the plastic solidifies in the joint region, so that an integrally bonded connection is produced and a single composite plastic part is formed from the intermediate element 4 and the magnet ring 2. In the radial recess bounded by the recess 43 and the end face 21, the flange 31 is secured by form fit in regard to the axial direction.

[0054] Alternatively, a fluid or pastelike adhesive can be introduced between the joining surfaces 22 and 42, being optimally adapted in terms of an integrally bonded connection to the plastic materials of the magnet ring 2 and the intermediate element 4.

[0055] FIG. 6 shows a detail view of a further embodiment, in which an intermediate element 4′ is fashioned as a ring and arranged between the end face 21 of the magnet ring 2 and the rear end face 33 of the flange 31. The end face 41 is integrally bonded to the end face 21 in the region of joining surfaces, not shown separately here, and possibly formed similar to the aforementioned embodiment. By its axially opposite end face 45, the intermediate element 4 is firmly joined to the end face 33 of the carrier sleeve 3.

[0056] In the embodiment per FIG. 7, the flange 31 and the intermediate element 4′ comprise aligned axial apertures or openings 35 and 46, which are flush with a recess 25 in the end face 21 of the magnet ring 2. A positioning pin 6 can be inserted into the recess 25 through the apertures 35 and 46 in order to position the parts 2, 3 and 4′ exactly relative to each other during the mounting process. After the mounting, the positioning pin 6 can be pulled out once again in the axial direction, as indicated by the double arrow.

[0057] A similar embodiment to FIG. 6 is shown by FIG. 8, where the intermediate element 4 comprises in addition a form-fitting element 44 on the end face 41, corresponding in a form-fitting manner to a depression 24 in the magnet ring 2.

[0058] FIG. 9 illustrates another embodiment, which is very similar to the embodiment per FIG. 6. However, the integrally bonded connection is done by a laser welding using the laser 7. In this case, the frequency of the laser beam 71 needs to be chosen and attuned to the material of the carrier sleeve 3 so that the laser beam 71 penetrates the carrier sleeve 3. At least at the end face 21 of the magnet ring 2 there occurs a welding 72 with the end face 41 of the intermediate element 4′. However, it is also possible, by proper choice of the material of the carrier sleeve, to provide for a welding 73 between the end face 45 of the intermediate element and the end face 33 of the flange 31 of the carrier sleeve 3.

[0059] FIG. 10 illustrates a further embodiment which is very similar to the embodiment per FIG. 6. However, the form-fitting connection occurs, as already in the embodiment per FIG. 9, by a laser welding using the laser 7. It is not necessary to make sure that the frequency of the laser beam 71 is chosen such that the laser beam 71 penetrates the material of the carrier sleeve 3. At least at the end face 21 of the magnet ring 2 there occurs a welding 72 with the end face 41 of the intermediate element 4′. However, it is also possible, by proper choice of the material of the carrier sleeve, to provide for a welding 73 between the end face 45 of the intermediate element and the end face 33 of the flange 31 of the carrier sleeve 3. Further welds 74 and 75 can likewise be made, if accessible.

[0060] The features of the individually described embodiments of the invention may be combined or exchanged with each other, so far as is feasible, without leaving the realm of the invention.

LIST OF REFERENCE NUMBERS

[0061] 1 Transducer assembly [0062] 2 Magnet ring [0063] 21 End face [0064] 22 Joining surface [0065] 23 Protrusion [0066] 24 Depression [0067] 25 Recess [0068] 3 Carrier sleeve [0069] 31 Flange [0070] 32 End face [0071] 33 End face [0072] 34 Form-fitting element [0073] 35 Aperture [0074] 4, 4′ Intermediate element [0075] 41 End face [0076] 42 Joining surface [0077] 43 Recess [0078] 44 Form-fitting element [0079] 45 End face [0080] 46 Aperture [0081] 5 Welding punch (sonotrode) [0082] 6 Positioning pin [0083] 7 Laser [0084] 71 Laser beam [0085] 72, 73, 74, 75 Laser welding