Slip ring of slip ring seal and method for producing same

Abstract

The invention relates to a sliding ring of a sliding ring seal assembly, comprising: a sintered, ceramic ring (41) having a sliding surface (4a), said ring being made of an electrically non-conductive ceramic material; the invention relates to a sliding ring (41), comprising a sliding surface (4a) and an electrically conductive contact body (42), which is provided for electrical contact and is arranged in a recess (40) in the ring (41), the electrically conductive contact body (42) having a first region (42a) and a second region (42b), the first region (42a) being arranged in the recess (40) on an end of the recess (40) facing the sliding surface (4a) and filling a part of the recess (40), and the second region (42b) being arranged in the recess (40) on an end of the recess (40) facing the sliding surface (4a). Wherein the first region (42a) is made of a ceramic first electrically conductive material having a first hardness, the second region (42b) is made of a second electrically conductive material having a second hardness, and the first hardness of the first region (42a) is greater than the second hardness of the second region (42b).

Description

Technical Field

[0001] The present invention relates to a slip ring of a slip ring seal device, a slip ring seal assembly, and a method for manufacturing a slip ring. Background Art

[0002] Slip rings of different configurations of slip ring seal devices are known from the prior art. Recently, in order to monitor the slip ring, for example, to monitor its wear condition, sensing devices are increasingly arranged on the sliding surface of the slip ring. This has given rise to a series of problems, namely that the sensing device located on the sliding surface must be electrically contacted. Since the sensing device is located on the sliding surface, it is necessary to conduct electrical contact through the slip ring. Because the material of the slip ring often uses very brittle ceramics, the drilled holes or similar structures that must be processed in the slip ring to achieve electrical contact particularly have the risk that invisible damage and cracks may occur in the slip ring. In addition, the sliding surface of the slip ring is usually coated, for example, with a diamond coating. However, the drilled holes extending to the sliding surface in the slip ring, even if these holes are filled with material, are very disadvantageous because coating peeling often occurs at the edges of the drilled holes. Since the coating is usually carried out in the last step of the slip ring manufacturing process, for example, when applying a diamond coating, extremely high process temperatures of up to 900 °C will occur. This will cause thermal technical problems for the low melting point metals that may exist in the slip ring for electrical contact because the melting points of such metals are significantly lower than the temperature of coating the coating.

[0003] In addition, it must be ensured that for the electrical contact drilled holes extending to the sliding surface, no aggravated crack formation occurs either at the edges of the drilled holes or on the materials arranged in the drilled holes. Moreover, it must also be possible to achieve simple and reliable electrical contact with the materials filling the drilled holes. Summary of the Invention

[0004] Therefore, an object of the present invention is to provide a slip ring, a slip ring seal assembly, and a method for manufacturing a slip ring, which can achieve reliable electrical contact with the sensing device on the sliding surface of the slip ring under a simple structure and easy and low-cost manufacturing and implementation.

[0005] This object is solved by a slip ring having the features of claim 1, a slip ring seal assembly having the features of claim 14, and a method having the features of claim 15. The dependent claims respectively show preferred improvement schemes of the present invention.

[0006] The sliding ring of the sliding ring seal assembly having the features of claim 1 according to the present invention has the advantage, in contrast, that a simplified and reliable electrical contact through the sliding ring up to the sliding surface can be achieved. Thereby, in particular, sensors can be electrically contacted, which are arranged on the sliding surface of the sliding ring or in the vicinity of the sliding surface of the sliding ring or in the sliding ring. However, for example, it is also possible that an electrical current circuit passes through the sliding ring, which can be used, for example, for wear measurement, i.e., the electrical current circuit is arranged such that when wear occurs at the sliding surface of the sliding ring, the electrical current circuit is interrupted in the case of relatively severe wear. Here, the sliding ring can be made of a non-conductive ceramic material, which is advantageous in terms of its suitability as a sliding ring material. This is achieved according to the present invention in that the sliding ring has a sintered, ceramic ring having a sliding surface, wherein the ceramic ring is made of a non-conductive ceramic material. In addition, a conductive contact body is provided, and the conductive contact body for electrical contact is arranged in the ring. The conductive contact body is arranged in a notch in the ring, for example, a notch similar to a hole and completely fills the notch. The conductive contact body includes a first region and a second region, wherein the first region is arranged at the end of the notch facing the sliding surface in the notch, and the second region fills the remaining notch. The second region is thus arranged on the side of the sliding ring facing the back in the notch. The first region and the second region are each made of a conductive material, wherein the first conductive material of the first region has a greater hardness than the second conductive material of the second region. Thereby, the first conductive material having a greater hardness abuts on the side facing the sliding surface. Thereby, crack formation on the sliding surface can be avoided, which often occurs at the edge of the notch or in the conductive material of the contact body in the prior art. The first region is made of a conductive ceramic material here. The second region of the conductive contact body facing away from the sliding surface is made of a conductive material and can thus be optimized for excellent electrical contact with a wire or the like at its outlet side from the sliding ring for connection to a power supply and / or an evaluation unit or a similar device.

[0007] Since the first region is made of a ceramic material which preferably has similar thermal expansion characteristics to the material of the ceramic ring, the sliding ring manufactured in this way nevertheless has excellent sliding ring characteristics and enables a wide range of applications in terms of maximum pressure and maximum temperature.

[0008] Thereby, a ceramic sliding ring can be provided which is conductive only in the region of the conductive contact body by introducing the conductive contact body. Since not only the ring but also the first region of the contact body is made of a ceramic material, it shows significant advantages during operation, for example, compared to a sliding ring in which only a metal material as a wire is arranged, because the heat generated on the sliding surface during the operation of the sliding ring seal assembly causes a very uniform volume change determined by temperature on the sliding surface in the sliding ring according to the present invention.

[0009] Particularly preferably, the first region of the conductive contact body is made of conductive SiSiC (silicon-infiltrated silicon carbide). This is a reaction-bonded, silicon-infiltrated SiC material, and the material has a very high hardness. The sintered ceramic ring preferably ensures and thus has almost the same thermal expansion characteristics as the SiSiC material. The second region is preferably a composite material comprising silicon and SiC. Here, metallic silicon in particular provides the conductivity of the second region of the conductive contact body. Thereby, electrical contact can be made in a simple manner at the exposed end in the recess of the material of the second region of the conductive contact body by means of a wire or the like. The electrical contact is preferably established by a welding connection or a brazing connection or a conductive adhesive bond. Alternatively, a metal pin or a metal sleeve or the like for electrical contact can also be provided in or on the second region.

[0010] The second region is thus preferably metallic silicon, which is reinforced by incorporating SiC components. Preferably, the volume fraction of metallic silicon is greater than the volume fraction of SiC. Preferably, the volume fraction of metallic silicon is from 63% by volume to 72% by volume, and the volume fraction of SiC is from 18% by volume to 27% by volume. More preferably, the second region has gas-filled pores, and the volume fraction of the gas-filled pores is preferably between 5% by volume and 15% by volume.

[0011] The incorporated SiC in the second region ensures the formation of atomic bonds between the second region and the ceramic ring. Thereby, a uniform volume change is achieved in the temperature-dependent volume change of the ring with the conductive contact body. The second region is thus preferably made of a mixture consisting of metallic silicon and SiC and optionally a small volume fraction of gas-filled pores.

[0012] More preferably, the first region has a first length L1 in the axial direction of the recess, and the first length is less than the second length L2 of the second region in the axial direction of the recess. The first length L1 is preferably much smaller than the second length L2. The first length L1 is preferably in the range of 1 mm to 2 mm. Particularly preferably, the second length L2 is at least 10 times larger than the first length L1 here.

[0013] More preferably, the first region of the conductive contact body is connected to a sensor arranged on the sliding surface. The sensor preferably includes a conductive sensor layer, and the conductive sensor layer is made of the same material as the first region of the conductive contact body. Thereby, the sensor and the first region can be manufactured in a common step. Particularly preferably, the sensor layer is arranged in a recess in the sliding surface of the sliding ring here.

[0014] Alternatively, the sensor is a conductive sensor layer, and the conductive sensor layer is arranged on the entire sliding surface of the sliding ring.

[0015] More preferably, the sensor is covered with a coating as a protective layer. This coating is preferably a non-conductive layer, such as undoped diamond-like carbon (DLC). A coated slip ring is preferably used because the coating on the sliding surface of the slip ring can extend the service life of the slip ring by reducing wear. However, a series of problems exist when coating the sliding surface of the slip ring. Usually, a very high process temperature is required for this. For example, when applying a diamond coating, the temperature needs to be as high as 900 °C. However, the metal provided for electrical contact in the slip ring will melt at such a high temperature of about 900 °C. Therefore, so far, it has not been possible to provide a coated slip ring with a sensor, especially a wear sensor, because electrical contact of the sensor cannot be achieved by conventional contact methods. However, introducing electrical contact afterwards, such as providing holes in a ceramic ring after applying the coating, is very difficult and costly, and there is always a risk that the ceramic slip ring will crack or the coating will be damaged. Therefore, when producing such a coated ceramic slip ring with wires, the rejection rate is very high and it is generally uneconomical.

[0016] Particularly preferably, a large number of chemical bonds generated by sintering are formed between the conductive contact body and the ring. This ensures on the one hand that the contact body is reliably fixed in the ring and on the other hand that the thermally determined volume changes of the ring and the contact body occur particularly uniformly. It should be noted here that at least part of the regions of the contact body and the ring can be sintered together in one step, or alternatively the ring is pre-sintered and then the materials of the first and second regions of the contact body are introduced into the recesses and then in a second sintering step, the pre-sintered ring and the materials of the first and / or second regions of the contact body are sintered again.

[0017] The recess in the ring is preferably a through-hole recess. The through-hole recess can extend linearly from the back surface to the sliding surface in particular here, or alternatively from the inner circumferential surface or the outer circumferential surface to the sliding surface. Thereby, electrical contact of the slip ring is achieved on the circumferential surface, which is advantageous in some configurations of the slip ring seal assembly.

[0018] Particularly preferably, the second region of the conductive contact body forms an electrical interface for the conductive contact body on the outlet side of the contact body, and the wire can be arranged on the electrical interface in a simple manner, such as by brazing or welding.

[0019] Preferably, the slip ring is a fixed slip ring of the slip ring seal assembly and includes two conductive contact bodies in the ring of the slip ring to achieve electrical contact of the sensor through a closed circuit. Here, the first contact body among the contact bodies is an electrical lead-in wire, and the second contact body among the contact bodies is a return wire.

[0020] The ceramic ring of the slip ring is preferably made of a non-conductive material, i.e., having a conductivity of ≤ 10-8 S / m at 20°C.

[0021] Furthermore, the invention relates to a slip ring seal assembly having a slip ring according to the invention. Preferably, the slip ring according to the invention is used as the fixed slip ring of the slip ring seal assembly. The slip ring seal assembly particularly preferably includes a sensor on the fixed slip ring, and the sensor is electrically connected to a measuring device through a conductive contact body. The sensor is in particular a wear sensor.

[0022] Furthermore, the invention relates to a method for manufacturing a slip ring, in particular a fixed slip ring, of a slip ring seal assembly having the features of claim 15. The method herein includes the following steps: - Manufacturing an annular blank from a non-conductive ceramic material, - Machining a through notch in the blank, - Pre-sintering the blank - Filling a first partial area of the notch of the pre-sintered blank with a first conductive ceramic material, in particular SiSiC, - Introducing a second conductive material, in particular a composite material including metal silicon and SiC, into the remaining second partial area of the notch, and - Secondarily sintering the slip ring with the first conductive material and the second conductive material to form a first area and a second area of the conductive contact body in the notch, thereby manufacturing a ceramic slip ring having a non-conductive ceramic ring and a conductive contact body, wherein the hardness of the first area is greater than the hardness of the second area.

[0023] By the method according to the invention, a slip ring of a ceramic slip ring seal assembly can thus be manufactured, which is non-conductive yet has a conductive contact body composed of sintered, i.e., the first conductive material and the second conductive material located in the notch here. Thus, the slip ring can be obtained in two steps by sintering. Preferably, the sensor material of the sensor, in particular the wear sensor, is also sintered during the secondary sintering.

[0024] In this way, the advantages described above for the slip ring can be obtained.

[0025] Preferably, after the slip ring is sintered twice, a coating, in particular a diamond coating, is applied to the sliding surface of the slip ring. Description of the Drawings

[0026] The preferred embodiments of the invention will be specifically described below with reference to the drawings. In the drawings: Figure 1Schematic cross-sectional view showing a slip ring seal assembly having a slip ring according to the present invention, according to a first embodiment of the present invention, Figure 2 Showing Figure 1 Schematic cross-sectional view of a slip ring according to the present invention, Figure 3 Showing Figure 2 Enlarged view of, Figure 4 Schematic cross-sectional view of a slip ring according to a second embodiment of the present invention, and Figure 5 Schematic cross-sectional view of a slip ring according to a third embodiment of the present invention.

[0027] The following refers to Figures 1 to 3 Specifically describes the slip ring seal assembly 1 according to the first preferred embodiment of the present invention. Detailed description of the specific implementation

[0028] As can be seen from Figure 1 The slip ring seal assembly 1 includes a slip ring seal device 2, which has a rotating slip ring 3 and a stationary slip ring 4. The rotating slip ring 3 has a first sliding surface 3a, and the stationary slip ring 4 has a second sliding surface 4a.

[0029] A sealing gap 5 is defined between the two sliding surfaces 3a, 4a of the slip rings 3, 4. The slip ring seal assembly 1 here seals off the area 18 where the product to be sealed is present from the atmospheric area 19 on the shaft 14. The rotating slip ring 3 is here connected to the shaft 14 without relative rotation by means of a slip ring carrier 16 and bolts 17.

[0030] Furthermore, a preloading element 15 is provided, which preloads the rotating slip ring 3 against the stationary slip ring 4 in the axial direction along the central axis X-X.

[0031] The stationary slip ring 4 is sealed to the stationary housing member 20 by means of a first O-ring 21. The rotating slip ring 3 is sealed to the shaft 14 on its inner peripheral surface by means of a second O-ring 22.

[0032] The slip ring seal assembly 1 further includes a measuring device 6, which is especially provided for measuring the wear of the stationary slip ring 4 at its sliding surface 4a. The measuring device 6 is here connected to a sensor 7. The sensor 7 is arranged on the sliding surface 4a of the stationary slip ring 4.

[0033] The sensor 7 is arranged in a recess 43 in the sliding surface and is preferably a wear sensor.

[0034] For this purpose, an electrical contact of the sensor 7 on the sliding surface 4a must be provided, which is specifically formed by Figure 2 as can be seen. As can be seen from Figure 2 as can be seen, the fixed sliding ring 4 has a sintered, ceramic ring 41, which is made of a non-conductive ceramic material, in particular ensuring. In addition, two identically constructed conductive contact bodies 42 are arranged in the ring 41 for contacting the sensor 7.

[0035] As can be seen from Figure 2 and 3 as can be seen, the conductive contact bodies 42 extend from the back surface 4b to the sliding surface 4a. The conductive contact bodies 42 are arranged in notches 40 constructed in the ring 41 and extend linearly and parallel through the sliding ring 4.

[0036] The conductive contact bodies 42 include a first region 42a and a second region 42b.

[0037] On the exit side of the conductive contact bodies 42 on the back surface 4b of the sliding ring 4, there are respectively electrical interface regions 13 for the electric wires 8. Here, the electrical interface regions 13 are designed such that the electric wires 8 can be directly connected to the second region 42b.

[0038] The first region 42a is arranged in the notch 40 at the end of the notch 40 facing the sliding surface 4a and contacts the sensor 7. The second region 42b fills the remaining notch 40 and extends to the back surface 4b of the fixed sliding ring 4.

[0039] The first region 42a is made of a first conductive, ceramic material and is made of SiSiC in this embodiment. The second region is made of another second conductive material and is made of a mixture of metallic silicon and SiC in this embodiment to form a composite material. The composite material can have gas-filled pores with a maximum of 15% by volume.

[0040] The hardness of the ceramic first conductive material is greater than the hardness of the second conductive material here. The hardness of the first conductive material and the second conductive material can be determined by known methods, such as the Vickers method.

[0041] Cracking on the sliding surface can be prevented by constructing a harder first region 42a formed on the side facing the sliding surface 4a in the notch 40. This relates not only to cracks that may occur due to the notch 40, i.e., cracks at the edge of the notch 40 in the ceramic ring 41, but also to cracks in the conductive contact body 42 itself, which may further extend into the ceramic ring 41 after formation. The second region 42b of the conductive contact body 42, which has metal silicon and extends to the back surface 4b of the fixed sliding ring 4, enables direct and uncomplicated electrical contact with the wire. In particular, there is no need to provide metal pins or the like in the conductive contact body 42 for electrical contact. The wire 8 can be fixed directly, for example by welding.

[0042] Thus, the conductive contact body 42 having two different regions 42a and 42b prevents crack formation on the sliding surface and enables simple, rapid, and low-cost electrical contact with the wire 8 on the back surface of the fixed sliding ring 4.

[0043] As can be seen from Figure 2 In this embodiment, the sensor 7 is made of the same material as the first region 42a, i.e., SiSiC. This enables an easily manufacturable and simple connection between the sensor 7 and the conductive contact body 42. In particular, the sensor 7 is manufactured simultaneously with the first region 42a.

[0044] As can be seen especially from Figure 3 the first region 42a has a first length L1 in the axial direction of the contact body 42, and the first length is less than the second length L2 of the contact body 42 in the axial direction. The first length L1 is preferably in the range of 1 mm to 2 mm.

[0045] The thickness of the layer of the sensor 7 is furthermore less than the first length L1.

[0046] As Figure 1 shown, the two conductive contact bodies 42 are electrically connected to the measuring device 6 via the wire 8, and thus the sensor 7 is also electrically connected to the measuring device 6.

[0047] The fixed sliding ring 4 can be manufactured from a ceramic material in this case, so that in a first step, an annular blank is provided, which corresponds to the desired geometry of the fixed sliding ring 4 and is composed of a non-conductive ceramic material, such as SiC. At the same time or then, a recess 40 for a conductive contact body 42 is machined in the blank. The blank is then pre-sintered. Then the recess 43 is also machined. In the next step, the recess 43 for the sensor 7 is filled and the recess 40 is partially filled, wherein the same material, such as SiSiC, is used. The recess 40 is only partially filled here until the first length L1 is filled in the recess 40 to form a first region 42a. Then, a second conductive material is introduced into the still free region of the recess 40, which forms a second region 42b. Here, a mixture consisting of metallic silicon and a ceramic material, in particular SiC, can be introduced for the second region 42b. A secondary sintering of the slide ring then takes place, so that the first and second regions 42 a , 42 b are also sintered with the sensor 7 , wherein no SiSiC is present in the second region 42 b , but rather metallic silicon and SiC are present as a mixture.

[0048] As a result of the secondary sintering, in addition to the formation of SiSiC in the first region 42 a , a chemical bond is also achieved between the material of the ring and the material of the second region 42 b of the contact body 42 .

[0049] Since the thermal expansion of the ceramic of the ring 41 is substantially the same as the thermal expansion of the two regions 42a, 42b of the electrically conductive contact body 42, in particular in the case of thermal expansion, there is no reduction in the strength of the component as would occur if metallic materials were used for the electrical contact. As a result, there are no temperature-dependent restrictions in the selection of the coating 9. In particular, a diamond coating can be provided, which must be applied at a temperature of approximately 900° C., which can be applied after the production of the slide ring.

[0050] Furthermore, the atomic bonding between the material of the ring 41 and the material of the first region 42a of the electrically conductive contact body 42 in the secondary sintering step in particular achieves a smooth joining interface on the sliding surface, so that the sliding ring has excellent flatness and in particular also has a seamless transition between the material of the ring and the material of the electrical contact region.

[0051] This also achieves significantly improved emergency operation performance, in particular with regard to the possible emergency operation duration, since, for example, even after wear of the sensor 7, a flat surface, in particular a surface without edges at the transition between the two materials, remains on the sliding surface 4a, which can be used as a sliding surface for emergency operation.

[0052] This enables a fixed slip ring 4 to be provided, which for example has a sensor 7 for measuring wear on the sliding surface. If the sensor 7 is damaged due to wear, the current circuit through the contact body 42 is interrupted, which serves as a wear indicator. The sensor contact is integrated into the ring here and is ensured by a slidable ceramic material. A particularly simple thermoelectric contact can also be achieved directly at the slip ring by means of the second region 42b by welding or soldering without damaging the slip ring.

[0053] Figure 4 The slip ring 4 of a slip ring seal assembly according to a second embodiment of the invention is shown. Identical or functionally identical parts are labeled with the same reference numerals as in the first embodiment.

[0054] Differently from the first embodiment, the slip ring of the second embodiment has a coating 9. The coating is applied to the entire sliding surface of the slip ring and is a conductive DLC coating in this embodiment. This can be achieved, for example, by means of a doped DLC coating. The conductive coating 9 forms the sensor 7 and closes the circuit between two contact bodies 42 in the ring 41 here. If the coating 9 is worn, the circuit on the sliding surface is interrupted, so that the occurrence of wear can be indicated by the interrupted circuit on the measuring device 6. Otherwise, this embodiment corresponds to the foregoing embodiment, and thus reference can be made to the description given above.

[0055] Figure 5 The slip ring 4 according to a third embodiment of the invention is shown. Identical or functionally identical parts are labeled with the same reference numerals as in the foregoing embodiments.

[0056] As can be seen from Figure 5 the third embodiment basically corresponds to the first embodiment. However, in the third embodiment, no recess is provided on the sliding surface of the ring 41. The sensor 7 is provided as a conductive coating on a partial region of the sliding surface of the ring 41. The sensor 7 electrically connects two conductive contact bodies 42 to each other and closes the circuit here. A non-conductive coating 9' is formed on the sensor 7. The non-conductive coating 9' covers the sliding surface 4 of the entire slip ring. The structure of the contact body 42 with the first region 42a and the second region 42b again corresponds to the foregoing embodiment.

[0057] When the non-conductive coating 9' and the sensor 7 are worn, the circuit is disconnected again, so that the measuring device 6 can output a corresponding wear signal. Otherwise, this embodiment corresponds to the foregoing embodiment, and thus reference can be made to the description given above.

[0058] In addition to the above written description of the invention, for the purpose of supplementary disclosure of the invention, explicit reference is hereby made to Figures 1 to 5 the illustration of the invention in

[0059] List of Reference Signs 1 Sliding Ring Seal Assembly 2 Sliding Ring Sealing Device 3 Rotating Sliding Ring 3a First Sliding Surface 4 Fixed Sliding Ring 4a Second Sliding Surface 4b Back Surface 5 Sealing Gap 6 Measuring Device 7 Sensor 8 Electric Wire 9 Conductive Coating 9' Non - Conductive Coating 13 Electrical Interface 14 Shaft 15 Preloading Element 16 Sliding Ring Carrier 17 Bolt 18 Area with Product to be Sealed 19 Atmosphere Area 20 Housing Component 21 First O - Ring 22 Second O - Ring 40 Notch 41 Non - Conductive Ceramic Ring 42 Conductive Contact 42a First Region 42b Second Region 43 Recess in the Sliding Surface L1 First Length L2 Second Length X - X Central Axis.

Claims

1. A sliding ring of a sliding ring seal assembly, comprising: - a sintered, ceramic ring (41) having a sliding surface (4a), the ring being made of a non-conductive ceramic material, and - a conductive contact body (42) provided for electrical contact and arranged in a notch (40) in the ring (41), - wherein the conductive contact body (42) has a first region (42a) and a second region (42b), - wherein the first region (42a) is arranged in the notch (40) at an end of the notch (40) facing the sliding surface (4a) and fills a part of the notch (40), and - wherein the second region fills the remaining notch (40), - wherein the first region (42a) is made of a first conductive material of ceramic having a first hardness, and - wherein the second region is made of a second conductive material having a second hardness, and - wherein the first hardness of the first region (42a) is greater than the second hardness of the second region (42b).

2. The slip ring according to claim 1, wherein The first region (42a) is made of conductive SiSiC.

3. The slip ring according to any one of the preceding claims, wherein, The second region is composed of a composite material of metal silicon and SiC.

4. The slip ring according to any one of the preceding claims, wherein, The first region (42a) has a first length (L1) in the axial direction of the notch (40), and the first length is less than the second length (L2) of the second region (42b) in the axial direction of the notch (40).

5. The slip ring according to any one of the preceding claims, wherein, The first region (42a) is connected to a sensor (7) arranged on the sliding surface (4a).

6. The slip ring according to claim 5, wherein, The sensor (7) is a conductive sensor layer and is made of the same material as the first region (42a).

7. The slip ring according to claim 6, wherein, The sensor layer is arranged in a recess (43) in the sliding surface (4a) of the sliding ring.

8. The slip ring according to claim 5 or 6, wherein, The sensor (7) is a conductive coating arranged on the entire sliding surface.

9. The slip ring according to any one of claims 5 to 7, wherein The sensor (7) is covered by a non-conductive coating (9), and the non-conductive coating forms the sliding surface of the sliding ring.

10. The slip ring according to any one of the preceding claims, wherein, A chemical bond is formed by sintering between the conductive contact body (42) and the ring (41).

11. The slip ring according to any one of the preceding claims, wherein, The notch (40) is a through-notch that extends from the back surface (4b) to the sliding surface (4a), or the through-notch extends from the inner circumferential surface (4c) or the outer circumferential surface (4d) to the sliding surface (4a).

12. The slip ring according to any one of the preceding claims, wherein, A wire (8) is electrically connected to the conductive contact body (42) directly at the second region (42b).

13. The slip ring according to any one of the preceding claims, wherein, The sliding ring is the fixed sliding ring (4) of the sliding ring seal assembly, and there are two contact bodies (42) in the ring (41) for electrical contact with the sensor (7) to form a closed current loop.

14. A sliding ring seal assembly, comprising the fixed sliding ring (4) according to any one of the preceding claims and a measuring device (6), the measuring device being electrically connected to the contact body (42) of the sliding ring (4).

15. A method for manufacturing a sliding ring, comprising the following steps: - manufacturing an annular blank from a non-conductive ceramic material, - Machine a through notch (40) in the green body, - Presinter the green body, - Fill a partial area of the notch (40) with a first electrically conductive ceramic material, - Introduce a second electrically conductive material into the unfilled partial area of the notch (40), and - Sinter the slip ring with the first and second electrically conductive materials a second time in order to form a first area (42a) and a second area (42b) of an electrically conductive contact body (42) in the notch (40), thereby manufacturing a ceramic slip ring having a non-conductive ceramic ring (41) and an electrically conductive contact body (42), wherein the hardness of the first area is greater than the hardness of the second area.

16. The method according to claim 15, wherein Apply a coating (9) to the sliding surface (4a) of the slip ring after the second sintering and / or sinter sensor material also during the second sintering.

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