Radial shaft seal
The radial shaft seal addresses friction and assembly issues by using a metallic support body and clamping positioning ring with a cord spring, enhancing reliability and reducing costs in small shaft diameters and extreme conditions.
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- VR AUTOMOTIVE DICHTUNGSSYSTEME GMBH
- Filing Date
- 2019-08-28
- Publication Date
- 2026-05-21
AI Technical Summary
Existing radial shaft seals suffer from performance losses due to friction, leaks, high manufacturing costs, and assembly issues, particularly when used in small shaft diameters and under extreme temperatures or lubricating conditions, leading to increased wear and reduced reliability.
A radial shaft seal design featuring a metallic support body with a clamping positioning ring and a cord spring arrangement that secures elastomer and plastic sealing elements, allowing for axial displacement compensation and minimizing friction, while using cost-effective stamped parts for assembly.
The design significantly reduces power and leakage losses, ensures reliable sealing against axial movements, and maintains vacuum stability with minimal assembly defects, making it suitable for small shaft diameters and extreme conditions.
Smart Images
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Abstract
Description
[0001] The invention relates to a radial shaft seal for sealing a rotating shaft leading out of a space supplied with a fluid medium, comprising a sealing housing, at least one annular sealing body arranged in the sealing housing and sealing against the shaft by means of a sealing lip, and at least one annular, metallic support body positioning the sealing body(s) in the sealing housing, for sealing a liquid-filled interior space against an external space, preferably the atmosphere.
[0002] In the state of the art, such radial shaft seals are used in mechanical engineering, apparatus engineering and motor vehicle construction, for example for sealing the drive shafts of oil or coolant pumps.
[0003] From DE 3602500 A1, a radial oil seal is known which is inserted between a housing bore and a rotating shaft to seal a fluid located in a housing. The seal consists of a first sealing ring with a rubber sealing lip, which is tensioned against the shaft by means of a cord spring arranged radially above the rubber sealing lip on the sealing ring and bears directly against the rotating shaft in a sealing manner, and a second sealing ring with a synthetic resin sealing lip, which is arranged on the air side of the first sealing ring and adjacent to it. The synthetic resin sealing lip extends along the back of the rubber sealing lip and is also in sealing contact with the rotating shaft.
[0004] A rigid reinforcing ring is arranged on the air side of the second sealing ring and adjacent to it.
[0005] This reinforcing ring is curved along a bent section of the resin sealing lip to support the back side of this curved section. An outer ring is also positioned in the housing bore, which firmly secures the radially outer sections of the first and second sealing rings, as well as the reinforcing ring.
[0006] EP 2817539 B1 discloses a further radial shaft seal with the aforementioned features. This design is a tried and tested solution of the applicant, comprising two annular sealing elements, one made of a plastic and the other of an elastomer, which are arranged in a separate sealing housing made of stainless steel sheet and spaced apart from each other by a metallic, annular rotating part, a support body, which is fixedly arranged in the sealing housing by means of a press fit. These annular sealing elements are provided with sealing lips that bear in sealing contact with a running sleeve that is press-fitted onto the shaft.
[0007] A characteristic feature of this design is that both sealing lips, in their area in contact with the shaft or the sleeve, always form a flat sealing cylinder shaped towards the pressure side; at least the sealing element made of elastomer has an outer groove arranged on the outer circumference of the sealing cylinder, in which a cord spring is arranged that presses the sealing cylinder with the associated sealing lip against the sleeve which is fixed to rotation on the shaft, in order to minimize leakage losses when the shaft is rotating and to avoid leakage when the shaft is stationary.
[0008] However, this results in performance losses, which are due to the friction losses on the sealing cylinders of the respective sealing lips, which are pressed against the barrel sleeve over their entire surface by means of the cord spring(s).
[0009] According to EP 2817539 B1, the annular sealing body arranged on the pressure side (water side) consists of an elastomer and the sealing body arranged on the air side consists of a plastic, preferably polytetrafluoroethylene (PTFE).
[0010] The support bodies used to secure the position of the two sealing elements in the sealing housing are ring-shaped, metallic turned parts, the production of which inevitably requires a relatively high manufacturing effort.
[0011] For the arrangement of the air-side sealing element, EP 2817539 B1 proposes an axial press fit of the sealing element made of plastic, such as polytetrafluoroethylene (PTFE), between the sealing housing and the support body with axial securing of the support body by mechanical indentations from the outside.
[0012] When assembling the solution described in EP 2817539 B1, very high assembly forces must be applied to the support body that clamps the plastic sealing element in the seal housing. This forces, applied via the elastomeric sealing element, can damage the elastomeric sealing element during production, leading to rejects. However, to prevent the plastic sealing element from rotating with the shaft during the manufacture of seals according to EP 2817539 B1, a certain reject rate is accepted as a necessary consequence.
[0013] The partial rotation of the polytetrafluoroethylene (PTFE) sealing element, which occurs after prolonged use, leads to continuous destruction of this sealing element and consequently results in leaks.
[0014] However, another disadvantage of the aforementioned solution is that, particularly when using novel cooling fluids (weakly lubricating media), at speeds above 7,000 rpm, the fluid film between the shaft / sleeve and the sealing cylinder on the water-side elastomer seal tears away, so that, as has been reliably demonstrated in test series on test benches, a very significant temperature increase occurs at the respective seal from approximately 7,500 rpm, which leads to thermal damage of the coolant with a resulting deposit formation on the shaft surface (e.g. silicates from the thermally damaged coolant) and consequently to leaks.
[0015] Radial shaft seals with two different sealing elements, i.e., one made of an elastomer and a second of a plastic, are also described in JP H10-318 377 A and JP 2009-68 643 A. In the solution according to JP H10-318 377 A, the sealing surface of the elastomer sealing element located on the pressure / water side is clamped, as in the designs described above, by means of a spring located above the sealing surface, in this case directly against the shaft.
[0016] This solution also inevitably exhibits the disadvantages already explained in connection with the use of cord springs in the solutions described at the beginning, such as increased friction in the area of the elastomer sealing surface resulting from the circumferential force of the cord spring on the outer circumference of the elastomer sealing surface, which then inevitably leads to temperature increases and the associated power losses due to friction losses.
[0017] A key common feature of the two aforementioned solutions is that the respective elastomer sealing elements are always vulcanized onto ring-shaped flanged discs. This necessitates an additional vulcanization process for both designs, inevitably resulting in significantly increased manufacturing costs and recycling efforts.
[0018] In both solutions, the preload of the vulcanized elastomer is used to tension the second, air-side seal made of a plastic, for example a PTFE seal, in the respective ring flange disc.
[0019] For the final assembly of the respective seal, according to JP H10-318 377 A, the second seal is inserted into the ring-shaped flange disc with the vulcanized sealing body, between the air-side flange of the ring-shaped flange disc, i.e. the back wall and the elastomer sealing body, and clamped against the elastomer body in the area of the outer circumference of the elastomer body by means of a support ring.
[0020] In the solution according to JP H10-318 377 A, the sealing cylinders of both seals run directly on the shaft and are therefore subject to increased wear.
[0021] The solution according to JP 2009-68 643 A also has a significantly narrower ring collar compared to the solution according to JP H10-318 377 A.
[0022] Therefore, this solution absolutely requires a further, i.e., a second, ring washer between the ring collar and the air-side plastic seal in order to securely clamp the air-side plastic seal in the ring collar washer against the elastomer vulcanized onto the ring collar washer.
[0023] Since every elastomer has a so-called compression set (CSR), this leads to the preload of the elastomer seal decreasing over the service life / operating time of the seal.
[0024] This loss of preload is highly temperature-dependent and therefore occurs more rapidly the higher the temperature at which the seal is used.
[0025] This inevitably results in the preload of the elastomer becoming insufficient with increasing operating time when these seals are used in water pumps for motor vehicles, due to the prevailing temperatures of -40°C to +135°C. This is to prevent the "rotation" of the air-side plastic seal with the shaft in the ring flange washer, as already explained in connection with EP 2817539 B1.
[0026] The seals used in JP 2009-68 643 A are exclusively pure lip seals on whose sealing bodies no cord springs are arranged.
[0027] In the solutions according to US 2011 / 0 215 536 A1 and US 9695935 B2, as in the solution according to JP 2009-68 643 A, two ring-shaped sealing elements are used, whose sealing lips are not subjected to cord springs, whereby the solution according to US 2011 / 0 215 536 A1, as well as the solution according to JP 2009-68 643 A, rests directly on the shaft, and the solution according to US 9695935 B2 rests on a running sleeve, and in the contact area, always form a flat sealing cylinder shaped towards the pressure side.
[0028] In the solutions according to US 2011 / 0215536A1 and US 9695935B2, a narrow ring collar is also arranged on the air side, as a rear wall, within a sealing housing. Two support rings, one on the air side and one on the water side, are connected to this ring collar in a rotationally fixed manner.
[0029] The plastic sealing body, arranged on the air side and equipped with a sealing lip, is clamped between these by separately pressing the second elastomeric sealing body, arranged on the water side, between the water-side support ring and the sealing housing, and then securing it in its position elastically by means of another component, an adapter, arranged between the elastomeric sealing body and the sealing housing.
[0030] A very significant disadvantage of these solutions lies in the elastic positioning of the adapter, as just explained.
[0031] The previously described decrease in the preload of each elastomer seal over the service life / operating time in water pumps for motor vehicles leads, with increasing operating time, to the adapter falling out of its elastic tension in this design due to the decrease in the preload of the elastomer, and thus the seal (which then "falls apart" on the shaft sleeve) loses its sealing effect.
[0032] The solution according to JP 2009-68 643 A, as well as the solutions according to US 2011 / 0 215 536 A1 and US 9695935 B2, always have an elastomeric sealing element with an elastomeric sealing lip arranged on the water / pressure side and a plastic sealing element with a plastic sealing lip arranged adjacent to it on the air side. A small amount of commercially available grease is introduced between the two lips, which serves for short-term lubrication of the elastomeric lip.
[0033] Even with these solutions, where the elastomer sealing lip rests flat against the shaft or the running sleeve, increased wear occurs again after only a short operating time at higher speeds, i.e., at speeds above 7,000 rpm, in conjunction with the new coolants (weakly lubricating media), as already explained in connection with the solutions analyzed at the beginning. This is due to mixed friction conditions up to and including dry friction wear, and leads to damage by "burning" of the lip seals and to thermal damage of the coolant with the resulting leaks.
[0034] Furthermore, pure elastomer lip seals (i.e., those without a spring on the water-side sealing lip), whether according to the solution of JP 2009-68 643 A or those according to the solutions of US 2011 / 0 215 536 A1 and US 9695935 B2, also have the disadvantage that every elastomer has a compression set (CSR) which causes the preload to decrease depending on the operating temperature and the service life, thus significantly reducing the preload of the sealing lip against the shaft or the running sleeve at the coolant operating temperature and with increasing service life.
[0035] This leads to a partial vibration at the water-side sealing lip, causing a squeaking noise from the seal. Furthermore, when there is no system pressure (i.e., when the engine is off), this results in leaks and consequently higher warranty costs. The leakage when the engine is off also significantly reduces the vacuum stability.
[0036] This vacuum stability is always present in new vehicles, and allows the initial filling of the cooling systems to be carried out in such a way that the cooling system can be evacuated using a suction pump, tested for leaks, and then filled with coolant free of air using the generated vacuum.
[0037] Naturally, the described signs of wear on the sealing lips have no effect on the initial filling.
[0038] However, since many workshops already fill air-free systems under negative pressure as part of repair and maintenance work, the wear phenomena explained above, with their associated leaks during periods of inactivity, lead to more or less air entering the cooling circuit, depending on the operating time and the respective operating conditions, for example through leaky or worn sealing lips, with the resulting disadvantages.
[0039] Another disadvantage of all the above designs is that they can only meet the increased demands in the automotive sector, in conjunction with fuel-efficient combustion engines and electric vehicles, for ever smaller space requirements, ever smaller power losses, ever longer service life with a simultaneously decreasing weight, to a very limited extent, and mostly not at all.
[0040] The smaller radial shaft seal designs required in the automotive sector are characterized by shaft diameters of 9 mm and below (down to 3 mm). This is because such small shaft diameters meet the requirements for reduced weight, significantly lower friction and associated power losses, as well as considerably less wear, which also decreases with the shaft diameter due to the lower circumferential speeds. These "smaller" seals, i.e., seals for shaft diameters of 3 mm to 9 mm, are also required where electrically driven auxiliary pumps, whether water or oil pumps, with low electrical drive power are to be used.
[0041] Another problem, which arises, for example, with new bearing concepts in connection with the use of electric water pumps, is that in these applications the seals must compensate for axial displacements of the shaft of up to 2 mm.
[0042] Today, the technical challenge also includes sealing the smallest possible plain bearings, whether made of copper, sintered metal or plastic, which have a technically induced heat generation, and combining them with "small" radial shaft seals suitable for this application.
[0043] However, these applications of the “small” radial shaft seals with shaft diameters in the range of 9 mm to 3 mm, which, compared to today’s designs, are also intended to compensate for axial displacements of the shafts, i.e. axial shaft movements, inevitably require completely new radial shaft seal designs.
[0044] Thus, the designs currently used in the state of the art in conjunction with shaft diameters of over 9 mm inevitably require undercuts.
[0045] However, these undercuts lead to increased reject rates during vulcanization in smaller designs (with shaft diameters of 9 mm or less) due to the decreasing material thickness, as the elastomer tears very easily during both manual and machine demolding of small components. Furthermore, the support components, whether made of plastic or metal, that need to be mounted in the decreasing undercuts can no longer be manufactured efficiently with the precision required for these small sizes.
[0046] Such small plastic parts are inevitably no longer sufficiently stable to compensate for both the applied forces and the temperature differences.
[0047] Furthermore, the installation space specified nowadays for the entire "small" seal, i.e., an outer / bore diameter of 16 mm to 8 mm specified for these small shaft diameters of 9 mm to 3 mm, does not allow for radial overlap of several components, as is common with larger seals, since their material thicknesses are simply too small for both manufacturing and assembly.
[0048] It should also be taken into account that the minimum tolerances required for effective manufacturing of metal, plastic and elastomer components do not decrease even when the seal is miniaturized, so that these minimum tolerances naturally have a correspondingly greater negative impact when seals (seal diameters) become smaller.
[0049] For smaller seals, the tolerance chains must therefore be kept as minimal as possible. Currently used larger seals often have relatively large tolerance chains, which, in state-of-the-art designs, negatively impact both production and function. However, these tolerances must currently be tolerated by both manufacturers and users. Furthermore, since the same pressure and operating conditions apply to smaller seals, but thinner material thicknesses are essential, the state-of-the-art design variants for radial shaft seals, which utilize larger shaft and bore diameters and therefore greater material thicknesses, are unsuitable for the ever-decreasing shaft diameters, as explained above.
[0050] The object of the invention is therefore to develop a novel radial shaft seal for sealing a rotating shaft leading out of a space filled with a fluid medium against the atmosphere, which is suitable for sealing oil or oil-like media, but also for coolant pumps using low-viscosity, water-based coolants with slightly lubricating additives, and which is intended to eliminate the aforementioned disadvantages of the prior art, and also those associated with small shaft diameters, i.e.For shaft diameters from 9 mm to 3 mm, the radial shaft seal significantly reduces power and leakage losses, while also effectively compensating for axial shaft movements, significantly increasing reliability and service life, reliably preventing standstill leakage, and ensuring "air-free" vacuum filling of coolant pumps with small shaft diameters in the range of 9 mm to 3 mm even after extended use. Furthermore, this novel radial shaft seal, which is to be developed, should be very easy to manufacture and assemble, so that, in addition to manufacturing costs, assembly costs in final production can be significantly reduced compared to current state-of-the-art solutions.
[0051] According to the invention, this problem is solved by a radial shaft seal according to the features of the main claim of the invention. Advantageous embodiments, details and features of the invention will become apparent from the dependent claims and the following description of the solution according to the invention with reference to several exemplary embodiments in conjunction with the associated drawings, which show the use of the solution according to the invention in several embodiments.
[0052] The invention is explained in more detail below with reference to several exemplary embodiments in conjunction with 13 figures.
[0053] This shows: Fig. 1 : the radial shaft seal according to the invention, arranged in a countersunk bore in the working housing 2 of a coolant pump, with a shaft diameter of the shaft 3 of 6 mm and a bore diameter of the countersunk bore of 13 mm, shown in section in side view after its installation; Fig. 2 : the radial shaft seal according to the invention as a two-lip system with a different design of the clamping positioning ring 23 with a sliding bearing 42 arranged in between after installation in a sleeve 41, in side view in section; Fig. 3 : the radial shaft seal according to the invention, arranged in a sealing housing 5 with mounting collar, for a sealing seat in a working housing 2 with a bore diameter of 16 mm, and a shaft diameter of the shaft 3 of 8 mm, after installation in a working housing 2 of a coolant pump, in side view in section; Fig. 4 : the radial shaft seal according to the invention during assembly, with the plastic sealing body 9 positioned securely in a sealing housing 5 with mounting collar by the support body 13, in side view, in section; Fig. 5: an analogue to Fig. 3. Assembled radial shaft seal according to the invention in the final assembly state / delivery state, i.e. before installation in a working housing 2 of a coolant pump, in side view in section; Fig. 6 : the detail Z of the radial shaft seal according to the invention as shown in Fig. 5; Fig. 7 : the detail Y of the radial shaft seal according to the invention as shown in Fig. 5; Fig. 8: an analogue to Fig. 3. Radial shaft seal according to the invention, in a laser-welded embodiment, in the final assembly / delivery state, i.e., before installation in a working housing 2 of a coolant pump, in side view in section; Fig. 9 : the detail X of the radial shaft seal according to the invention as shown in Fig. 8; Fig. 10: the top view of the one in the Fig. 8 Radial shaft seal according to the invention shown in the final assembly state; Fig. 11: another invention, analogous to Fig. 5 and Fig. 8 assembled radial shaft seal, however with fixing cones arranged on the circumference of the seal housing 5 in the form of positioning notches 39, in the final assembly state / delivery state, i.e. before installation in a working housing 2 of a coolant pump, in side view in section; Fig. 12: the detail W of the radial shaft seal according to the invention Fig. 11; Fig. 13: the top view of the in the Fig. 11 Radial shaft seal according to the invention shown in the final assembly state; Fig. 14: the temperature profile over the rotational speed of the radial shaft seal according to the state of the art (according to EP 2817539 B1); Fig. 15: the temperature profile over the rotational speed of the radial shaft seal according to the invention.
[0054] The Fig. Figure 1 shows the radial shaft seal according to the invention, arranged in a countersunk bore in the working housing 2 of a coolant pump, with a shaft diameter of 6 mm and a bore diameter of the countersunk bore of 13 mm, in a side view in section after its installation. In this embodiment, it is characteristic that the bore in the working housing 2 is designed as a cylindrical countersunk bore, so that it directly forms the seal housing 5 with its rear wall 6 and the shaft passage bore 7a arranged in the rear wall 6.
[0055] The radial shaft seal according to the invention for sealing a rotating shaft 3 extending from a pressure chamber 1 of a working housing 2 filled with a fluid medium against an external space 4, the atmosphere, with a sealing housing 5 arranged in a bore of the working housing 2, having a rear wall 6 and a shaft passage bore 7a arranged in this rear wall 6, wherein at least one elastomer sealing element 8 with an elastomer sealing lip 10 arranged on the pressure chamber side is arranged in the sealing housing 5 such that this elastomer sealing lip(s) 10 bears directly against the shaft 3 or a running sleeve 12 arranged non-rotatably on the shaft 3, wherein the elastomer sealing element 8 is positioned exactly relative to the sealing housing 5 by means of a metallic support body 13 provided with an annular shaft passage bore 7b, is characterized by the fact thatthat a support body fixing collar 15 with a support body fixing cylinder 16 is arranged on the outer edge of the support body 13 on the sealing housing side, wherein the outer diameter of the support body fixing cylinder 16 has an interference with the inner diameter of the associated inner wall 17 of the sealing housing 5, so that the support body 13, which in the final assembly state is press-fitted with its support body fixing cylinder 16 inside the sealing housing 5, wherein the support body 13 is provided with a support body web 18 extending radially to the support body fixing collar 15, and a support body positioning cylinder 21 with a support body positioning cylinder outer shell 22 is arranged inside the support body web 18 of the support body 13.
[0056] In this context, it is essential that a support collar 19, tapering towards the pressure chamber 1, i.e. towards the shaft passage 7b, is arranged on the support body positioning cylinder 21 adjacent to the pressure chamber side, between the pressure chamber-side end of the support body positioning cylinder 21 and the free end of the support body 13, which is provided with a shaft passage bore 7b on the pressure chamber side, and which has a support collar edge 20 at its free end on the pressure chamber side, which is provided with the shaft passage bore 7b in the support body 13.
[0057] A characteristic feature is that the elastomer sealing body 8 has a sealing body positioning cylinder 27, which rests on the support body web 18 with its end face 28 on the outside side, and which is radially clamped with its inner shell 30 against the support body positioning cylinder outer shell 22 and with its outer shell 29 radially against the inner wall 17 of the sealing housing 5.
[0058] A key aspect of the invention is that a clamping positioning ring 23 is arranged on the pressure chamber side of the sealing body positioning cylinder 27 of the elastomeric sealing body 8, which engages with a positioning rib 24 arranged inside the clamping positioning ring 23, i.e. on the shaft side, in an annular clearance 31 arranged on the pressure chamber side of the sealing body positioning cylinder 27 of the elastomeric sealing body 8, which runs parallel to the support body positioning cylinder 21 and extends into the elastomeric sealing body 8 up to above the support body positioning cylinder 21 and thereby forms a preload sealing rib 26 on the elastomeric sealing body 8 which abuts the support body positioning cylinder 21, on which the elastomeric sealing lip 10 is arranged on the pressure chamber side.
[0059] According to the invention, a clamping ring fixing cylinder 25 is arranged on the outside of the clamping positioning ring 23, i.e. opposite the positioning rib 24 on the housing side, the outer diameter of which has an excess compared to the inner diameter of the associated inner wall 17 of the sealing housing 5, so that it too is joined inside the sealing housing 5 by means of a press fit in the final assembly state.
[0060] It is also essential that the preload sealing rib 26 of the elastomer sealing body 8 rests against the outer shell 22 of the support body positioning cylinder 21.
[0061] A characteristic feature is that a freely supporting arched web 32 is arranged on the prestressing sealing rib 26 in the area above the support collar 19, which transitions above the edge of the support collar 20 into an equally freely supporting arched web 33, on the pressure chamber side of which the elastomeric sealing lip 10 is then arranged, which rests against the shaft 3, wherein above the supporting arched web 33 an external groove 34 is arranged on the outer circumference of the elastomeric sealing body 8, in which a cord spring 35 is arranged, which prestresses not only the supporting arched web 33 but also the freely supporting arched web 32 of the elastomeric sealing body 8, and thereby spring-elastically clamps the elastomeric sealing lip 10 against the shaft 3.
[0062] This in the Fig. The design of the radial shaft seal according to the invention, as shown in Figure 1, ensures the axial securing of the components without undercuts and, due to the absence of undercuts for axial securing of the radial shaft pump, enables, on the one hand, a small radial tolerance chain and, on the other hand, low-defect production of even small elastomer parts, since undercuts are the main cause of cracks when demolding the components from the vulcanization tool.
[0063] These disadvantages increase disproportionately with the increasing miniaturization of the elastomer parts.
[0064] Furthermore, the radial shaft seal according to the invention allows for an optimal assembly sequence, i.e., assembly one after the other, in which no assemblies have to be pre-assembled individually.
[0065] All assembly steps that require a minimum force when pressing into the sealing housing 5 can always be carried out directly on the metal parts.
[0066] In the solution according to the invention, there are no pressing processes that press directly onto the elastomer part.
[0067] This allows the accuracy during assembly to be increased using the solution according to the invention.
[0068] At the same time, it is easier to monitor the assembly steps, since there are fixed measuring points and it is not necessary to measure on the elastomer.
[0069] The solution according to the invention ensures a significantly simplified manufacturing and assembly of the seal with low reject rates in production.
[0070] The highly elastic design of the inventive prestress sealing web 26, with the inventively freely supporting tension arch web 32 and the adjoining, also freely supporting, and prestressed with a cord spring 35 according to the invention, support arch web, with the highly elastic, prestressed elastomer sealing lip 10 arranged at its free end, allows for the first time axial displacements of the shaft 3 in the range of 10% to 20% of the shaft diameter.
[0071] All these properties according to the invention make it possible to use the radial shaft seal according to the invention also for sealing sliding bearings of electrically driven shafts.
[0072] The Fig. Figure 2 now shows such an application of the radial shaft seal according to the invention in conjunction with a sliding bearing of an electrically driven shaft.
[0073] The application shown here demonstrates the radial shaft seal according to the invention in the form of a two-lip system with a sliding bearing 42 arranged in between.
[0074] In this embodiment, a difference from the Fig. 1 different design of the clamping positioning ring 23 with a modified clamping ring fixing cylinder 25 was used.
[0075] This system is installed in a sleeve 41, which is mounted in the working housing 2 of a coolant pump, and in the Fig. 2 shown in the side view in section.
[0076] According to the invention, the sealing housing 5 with its rear wall 6 and a shaft passage bore 7a arranged in this rear wall 6 is formed in this embodiment by a sleeve 41 made of metal.
[0077] In the final assembly state, this sleeve 41 is arranged in a liquid-tight manner in a bore of the working housing 2.
[0078] A characteristic feature is that a radial shaft seal designed analogously to the previous embodiment is arranged in this sleeve 41, a sliding bearing 42 is arranged adjacent to the pressure chamber side in such a way that it rests axially on the clamping positioning ring 23, a sliding bearing rear wall 43 is arranged on this sliding bearing 42 on the pressure chamber side, against which the support body 13 of a further radial shaft seal designed analogously to the previous embodiment according to the invention rests axially.
[0079] As in connection with Fig. As already explained in section 1, a clamping positioning ring 23 is again arranged on the pressure chamber side of the sealing body positioning cylinder 27 of the elastomeric sealing body 8. This clamping positioning ring engages with a positioning rib 24 arranged on the inside of the clamping positioning ring 23, i.e., on the shaft side, in an annular clearance 31 arranged on the pressure chamber side of the sealing body positioning cylinder 27 of the elastomeric sealing body 8. This clearance runs parallel to the support body positioning cylinder 21 and extends into the elastomeric sealing body 8 up to above the support body positioning cylinder 21. In doing so, it forms a preload sealing rib 26 on the elastomeric sealing body 8, which abuts the support body positioning cylinder 21. The elastomeric sealing lip 10 is arranged on this preload sealing rib on the pressure chamber side. It is essential to the invention that the clamping positioning ring 23 is arranged on the outside, i.e.,Opposite the positioning rib 24 on the housing side, a clamping ring fixing cylinder 25 is arranged, the outer diameter of which has an interference fit with the inner diameter of the associated inner wall 17 of the sealing housing 5, so that this clamping positioning ring 23 is also firmly joined inside the sealing housing 5 by means of an interference fit in the sleeve 41 in the final assembly state. A key advantage of the assembly of the elastomer sealing elements according to the invention in the sleeve 41 is that none of the sealing assemblies need to be pre-assembled individually.
[0080] The assembly sequence of the radial shaft seal according to the invention allows for sequential assembly.
[0081] It is also essential that all assembly steps requiring a minimum force for pressing into the sealing housing 5 can be applied directly to the stable metal parts adjacent to the elastomer.
[0082] There are no pressing processes that apply direct pressure to the elastomer part. This ensures high accuracy during assembly.
[0083] Each assembly step can be precisely controlled because there are fixed measuring points and it is not necessary to measure on the elastomer.
[0084] In addition to easy assembly, this also ensures high quality, which minimizes the reject rate in production.
[0085] In the Fig. Figure 3 shows the radial shaft seal according to the invention, arranged in a sealing housing 5 with mounting collar, for a sealing seat in a working housing 2 with a bore diameter of 16 mm and a shaft diameter of the shaft 3 of 8 mm, after installation in a working housing 2 of a coolant pump, in a side view in section.
[0086] The radial shaft seal according to the invention for sealing a rotating shaft 3 leading out of a pressure chamber 1 of a working housing 2 filled with a fluid medium against the outside space 4, the atmosphere, with a metallic sealing housing 5 arranged in a bore of the working housing 2, having a back wall 6 and a shaft passage bore 7a arranged in this back wall 6, is characterized in that an elastomer sealing element 8 with an elastomer sealing lip 10 and a plastic sealing element 9 with PTFE and a plastic sealing lip 11 are arranged on the pressure chamber side of the sealing housing 5 such that these sealing lips, the elastomer sealing lip 10 and the plastic sealing lip 11, bear directly against the shaft 3, or, as shown in this exemplary embodiment, against a running sleeve 12 arranged non-rotatably on the shaft 3, wherein the two sealing elements, the elastomer sealing element 8 and the plastic sealing element 9,in their position relative to the sealing housing 5 by means of a metallic support body 13 provided with an annular shaft passage bore 7b are exactly positioned.
[0087] It is essential that in the area of the shaft passage bore 7a on the rear wall 6, a frustoconical sealing element contact collar 14 is arranged in the direction of the pressure chamber 1, under a contact cone angle α, inclined in the range of 25° to 38°.
[0088] In the embodiments of the solution according to the invention described here, the contact cone angle α lies in the range of 25° to 28°. The sealing element contact collar 14, inclined below the contact cone angle α, causes a desired deformation of the plastic sealing element 9, which in the present embodiment consists of polytetrafluoroethylene (PTFE), in the direction of the pressure chamber 1, so that it maintains its optimal sealing geometry even under pressure on the pressure chamber side, thereby minimizing the wear of the plastic sealing lip 11 of the plastic sealing element 9 and preventing the so-called "trumpet effect", i.e., a lifting of the front, pressure chamber-side area of the plastic sealing lip 11 from the shaft 3 or the running sleeve 12.
[0089] This sealing element mounting collar 14, inclined below the mounting cone angle α, ensures that the contact surface of the plastic sealing lip 11 remains almost constant regardless of the applied internal pressure, thus minimizing both wear and frictional heat at the sealing point and therefore also friction losses.
[0090] It is also characteristic that, as in Fig. As shown in Figure 4, a support body fixing collar 15 with a support body fixing cylinder 16 is arranged on the outer edge of the support body 13 on the sealing housing side, wherein the outer diameter of the support body fixing cylinder 16 has an interference with the inner diameter of the associated inner wall 17 of the sealing housing 5, so that the support body 13, as shown in Fig. 4 shown, in the final assembly state with its support body fixing cylinder 16 inside the sealing housing 5 is press-fitted in such a way that it presses the plastic sealing body 9 against the rear wall 6 with its support body web 18 adjoining the support body fixing collar 15, thereby ensuring a high positional stability of the support body 13 which is firmly fixed, i.e. pressed in, in the sealing housing 5.
[0091] The press fit of the support body 13 in the sealing housing 5 also ensures that the plastic sealing element 9 is securely clamped against the rear wall 6 of the sealing housing 5, thus guaranteeing high reliability of this seal throughout its entire service life due to the resulting resistance to rotation of the plastic sealing element 9. A further essential feature of the invention is that a support body positioning cylinder 21 with an outer casing 22 is arranged on the inside of the support body web 18 of the support body 13, wherein, on the pressure chamber side adjacent to the support body positioning cylinder 21, between the pressure chamber-side end of the support body positioning cylinder 21 and the free end of the support body 13, which is provided with the shaft passage bore 7b on the pressure chamber side, a channel extending towards the pressure chamber 1, i.e.,towards the shaft passage bore 7b, a tapered support collar 19 is arranged on the support body positioning cylinder 21, which has a support collar edge 20 at its free end on the pressure chamber side, which is provided with the shaft passage bore 7b in the support body 13.
[0092] However, according to the invention, the elastomer sealing body 8 also has a sealing body positioning cylinder 27 which, on the outside side, rests with its end face 28 on the support body web 18 and which is radially clamped with its inner shell 30 against the support body positioning cylinder outer shell 22 and with its outer shell 29 radially against the inner wall 17 of the sealing housing 5.
[0093] The high stresses occurring during continuous operation of the support body 13 mounted in the sealing housing 5 according to the invention are reliably transferred to the sealing housing 5 by its arrangement according to the invention.
[0094] A further characteristic feature is that a clamping positioning ring 23 is arranged on the pressure chamber side of the sealing body positioning cylinder 27 of the elastomer sealing body 8, which engages with a positioning rib 24 arranged inside the clamping positioning ring 23, i.e. on the shaft side, in an annular clearance 31 arranged on the pressure chamber side of the elastomer sealing body 8, which runs parallel to the support body positioning cylinder 21 and extends into the elastomer sealing body 8 up to above the support body positioning cylinder 21 and thereby forms a preload sealing rib 26 on the elastomer sealing body 8 which abuts the support body positioning cylinder 21, in the extension of which the elastomer sealing lip 10 is arranged on the pressure chamber side.
[0095] It is also essential to the invention that the device in the Fig. 6 as a detail Z of the Fig. 5 shown in detail, a clamping ring fixing cylinder 25 is arranged on the outside of the clamping positioning ring 23, i.e. opposite the positioning rib 24 on the housing side, the outer diameter of which has an excess compared to the inner diameter of the associated inner wall 17 of the sealing housing 5, so that it is press-fitted inside the sealing housing 5 in the final assembly state.
[0096] The solution according to the invention enables the use of cost-effective stamped parts for both the support bodies 13 and the clamping positioning rings 23, thereby ensuring a manufacturing and assembly-technically simple as well as very reliable and at the same time very cost-effective securing of the position of both sealing bodies, i.e. the elastomer sealing body 8 and the plastic sealing body 9, on and in the sealing housing 5.
[0097] According to the invention, the preload sealing web 26 of the elastomer sealing body 8 bears flatly against the outer shell 22 of the support body positioning cylinder 21, wherein a freely supporting arch web 32 is arranged on the preload sealing web 26 in the area above the support collar 19, which transitions above the edge of the support collar 20 into a similarly freely supporting arch web 33, on which the elastomer sealing lip 10 is then arranged on the pressure chamber side, which bears against the shaft 3, or against a running sleeve 12 arranged rotationally fixed on the shaft 3.
[0098] This solution according to the invention ensures optimal, very reliable and cost-effective positioning of both sealing elements, i.e. the elastomer sealing element 8 and the plastic sealing element 9, on and in the sealing housing 5 of the radial shaft seal according to the invention.
[0099] In the present embodiment, the elastomer sealing lip 10 rests against a running sleeve 12 which is arranged non-rotatably on the shaft 3 and which is made of stainless steel and has a surface hardness greater than 1120 HV.
[0100] In the present embodiment, the surface hardness of the barrel sleeve is 12 1450 HV.
[0101] The use of such bearing sleeves 12 with high surface hardness means that the shaft 3 can be manufactured much more cost-effectively, since the bearing sleeves 12 are manufactured separately and only fitted onto the shafts 3 in the area of the radial shaft seal. This prevents corrosion under the sealing lips, minimizes wear in the area of the sealing lip, even if foreign particles are "trapped" under the sealing lip, i.e., significantly reduces scoring on the running surfaces, thus ensuring that the running surfaces remain virtually wear-free, i.e., undamaged for the sealing effect, over a long period of actual use.The essential feature of the invention is that an outer groove 34 is arranged above the support arch web 33 on the outer circumference of the elastomer sealing body 8, in which a cord spring 35 is arranged, which, in addition to the support arch web 33, also simultaneously pre-tensions the freely supporting tension arch web 32 of the elastomer sealing body 8, and thereby clamps the elastomer sealing lip 10 spring-elastically against the shaft 3 or the running sleeve 12 which is arranged rotationally fixed on the shaft 3.
[0102] This arrangement according to the invention of a cord spring 35 above the support arch web 33 on the outer circumference of the elastomeric sealing body 8 causes, as shown in the Fig. 7, as detail Y of the Fig. 5, shown, an optimal distribution of the spring preload force F FV on the one hand, the clamping force F acting on the clamping arch web 32 of the elastomer sealing body 8 S, which defines the freely supporting arch web 32 of the elastomer sealing body 8 elastically prestressed so that the lip contact force F acting on the linear elastomer sealing lip 10 is defined L The elastomer sealing lip 10 presses optimally against the shaft 3, or the running sleeve 12 arranged non-rotatably on the shaft 3, thereby ensuring optimal vibration damping of the elastomer sealing lip 10 over the entire service life of the radial shaft seal according to the invention, and even preventing stick-slip tendency (vibration tendency) under unfavorable operating conditions (such as poorly lubricating coolants, high coolant temperatures and low speeds, such as the idle speed, both individually and in combination), thus ensuring a safe and reliable, high sealing effect with minimal friction losses over the entire service life.
[0103] At the same time, this radial shaft seal according to the invention provides optimal sealing lip preload, which also counteracts the compression set (CSR) of the elastomer and minimizes both friction and wear, whereby even in the event of wear that may occur, an automatic optimal elastic readjustment of the contact zone is carried out by the cord spring 35, so that the vacuum stability is also ensured over the entire service life of the radial shaft seal, and any leakage at / over the sealing points between the elastomer sealing lip 10 and the running sleeve 12 is avoided.
[0104] The arrangement according to the invention, in its interaction, also ensures that optimal vibration damping of the elastomer sealing lip 10 with optimal sealing lip preload and minimal friction losses can be guaranteed over the entire service life of the radial shaft seal according to the invention, thereby minimizing friction and wear, and also ensuring the vacuum stability over the entire service life of the radial shaft seal and preventing leaks at / over the sealing points between the elastomer sealing lip 10 and the running sleeve 12.
[0105] Another feature of the invention is that a lubrication chamber 36 is arranged between the support body 13, the plastic sealing body 9 and the shaft 3 or the running sleeve 12, in which a lubricating medium 37, in the present embodiment a PTFE grease, is arranged.
[0106] This prevents the sealing lip from sticking during transport to the end customer and ensures that the sealing lip is not torn off during initial commissioning. At the same time, the running-in behavior of the sealing lips is improved, the sealing lip is lubricated even during dry tests, the friction temperature is reduced under unfavorable operating conditions, and even the tendency to stick-slip (noise and squeaking due to vibration) under unfavorable operating conditions (such as poorly lubricating coolants, high coolant temperatures and low speeds, e.g., idle speed, in combination) is prevented.
[0107] On the outer circumference of the sealing housing 5, as shown in the Fig. 3 shown, sealing lacquer 38 arranged around the perimeter.
[0108] This sealing lacquer 38 ensures that unevenness in the housing bore is compensated for, and that the static tightness between the working housing 2 and the sealing housing 5 is guaranteed over the entire service life of the radial shaft seal.
[0109] By means of this radial shaft seal according to the invention presented above, it is possible for the first time to meet the increased requirements of the automotive sector, in particular for fuel-efficient combustion engines and electric vehicles, with ever smaller space requirements, ever smaller power losses, ever longer service life and simultaneously decreasing weight.
[0110] Since these smaller radial shaft seals for shafts with a diameter of 9 mm down to 3 mm can meet the requirements in the respective overall concept for less weight, significantly lower friction and associated power losses, as well as significantly less wear, which also decreases significantly with the smaller shaft diameter due to the decreasing circumferential speeds.
[0111] Naturally, the design according to the invention can also be used for radial shaft seals with shaft diameters of over 9 mm, where it can serve to seal oil or coolants, and also reduce leakage losses in the larger designs, compensate very well for axial shaft movements, significantly increase reliability and service life, reliably prevent standstill leakage, and even after prolonged use still ensure "air-free" vacuum filling of coolant pumps, whereby this "larger" radial shaft seal is also very easy to manufacture and assemble, so that in addition to the manufacturing costs, the assembly costs in final production are also significantly reduced compared to current state-of-the-art solutions.
[0112] The Fig. 8, Fig. 9 and Fig. 10 show an analogous to the one in the Fig. 5, Fig. 6 and Fig. The radial shaft seal according to the invention is constructed in the form shown in Figure 7, but in a laser-welded embodiment in the final assembly / delivery state, i.e. before installation in a working housing 2 of a coolant pump, shown in a side view in section, which is characterized in that the clamping ring fixing cylinder 25 of the clamping positioning ring 23 is connected in the press-fit state, and in addition by means of one or more weld seams 40 arranged between the seal housing 5 and the clamping positioning ring 23, which are uniformly distributed around the circumference in the edge area, thus not only force-fit but also material-fit to the seal housing 5.
[0113] This ensures a high degree of positional stability of the clamping ring fixing cylinder 25 of the clamping positioning ring 23, which is firmly fixed in the sealing housing 5, i.e. pressed / tensioned, and subsequently welded in this tensioned state.
[0114] In this context it is also essential that the weld seam(s) 40 arranged between the clamping positioning ring 23 and the sealing housing 5 is / are preferably designed as a laser weld seam(s).
[0115] This additional material-bonded connection using laser welding increases the reliability of the composite many times over, as the laser welds can withstand very high tensile, compressive, torsional and bending stresses.
[0116] The Fig. 11, Fig. 12 and Fig. 13 also show an analogous pattern to that in the Fig. 5, Fig. 6 and Fig. The radial shaft seal according to the invention, constructed in the form shown in Figure 7, is shown here with fixing cones in the form of positioning notches 39 arranged on the circumference of the seal housing 5, in the final assembly / delivery state, i.e., before installation in a working housing 2 of a coolant pump, in a side view in section. It is advantageous that fixing cones, which are formed, for example, by positioning notches 39, are arranged on the circumference of the seal housing 5 to secure the position of the clamping ring fixing cylinder 25 of the clamping positioning ring 23 in the seal housing 5, and which, in addition to the press fit, provide a positive locking mechanism and additional anti-rotational stability of the clamping positioning ring 23 in the seal housing 5 (analogous to a laser welded connection).
[0117] In the Fig. 14 and Fig. Figure 15 shows the measurement results of a test setup where, under the same test conditions, the radial shaft seal according to EP 2817539 B1 was used. Fig. 14, and with the radial shaft seal according to the invention in Fig. The temperature profile shown in section 15 was determined over the rotational speed.
[0118] The same coolant was used both times.
[0119] The temperature measurement was taken (from the rear) directly at the elastomer sealing lip at a pressure of 2.5 bar in the pressure chamber, the coolant chamber, and at a coolant temperature of 107 °C, always after 3 minutes of continuous operation at the specified speed.
[0120] The Fig. Figure 14, which shows the temperature profile over the rotational speed when using the radial shaft seal according to EP 2817539 B1, shows that at the water-side arranged elastomer sealing element 8, a significant temperature increase already occurs at the seal from rotational speeds of over approximately 7,000 rpm.
[0121] It is assumed that this is due to the fact that, in the case of the elastomer sealing lip used in EP 2817539 B1, at higher speeds, i.e. at speeds in the range of 7,000 rpm, the fluid film between the shaft or the running sleeve and the elastomer sealing lip tears away, and this then leads to a temperature increase at the elastomer sealing lip that increases significantly with increasing speed.
[0122] The Fig. Figure 15 shows the temperature profile over the rotational speed determined with the same experimental setup, but now using the radial shaft seal according to the invention.
[0123] The comparison of both diagrams clearly demonstrates that, with the radial shaft seal according to the invention, especially at higher speeds, the power losses, i.e., the friction losses, could be significantly reduced compared to the current state of the art, and thus the reliability as well as the service life of the radial shaft seal according to the invention could be substantially increased.
[0124] By means of the solution according to the invention, it has thus been possible to develop a novel radial shaft seal for sealing a rotating shaft leading out of a space filled with a fluid medium against the atmosphere, which is suitable for sealing both oil or oil-like media, but also for coolant pumps, using low-viscosity, water-based coolants with slightly lubricating additives, eliminates the disadvantages of the prior art, and also the disadvantages associated with small shaft diameters, i.e.For shaft diameters from 9 mm to 3 mm, it significantly reduces power and leakage losses, while also effectively compensating for axial shaft movements, significantly increasing reliability and service life, reliably preventing standstill leakage, and ensuring "air-free" vacuum filling of coolant pumps with small shaft diameters in the range of 9 mm to 3 mm even after extended use. Furthermore, the novel radial shaft seal presented above is very easy to manufacture and assemble, thus significantly reducing both manufacturing and final assembly costs compared to current state-of-the-art solutions. Reference symbol compilation 1 pressure chamber 2 work housings 3rd wave 4 Outdoor area 5 sealing housings 6 Back panel 7a Shaft passage hole in the rear wall 6 7b Shaft passage bore in the support body 13 8 elastomer sealing elements 9 plastic sealing elements 10 elastomer sealing lip 11 Plastic sealing lip 12 Barrel sleeve 13 support bodies 14 Sealing element assembly 15 Support body fixation band 16 support body fixing cylinders 17 Interior wall 18 Support body web 19 Supporting ligament 20 Supporting rim 21 support body positioning cylinders 22 Support body positioning cylinder outer casing 23 Clamping positioning ring 24 Positioning bridge 25 clamping ring fixing cylinders 26 Preload sealing rib 27 Sealing element positioning cylinders 28 Front 29 Outer shell 30 inner jacket 31 Release 32 arch bridge 33 Supporting arch bridge 34 Outer groove 35 Cord spring 36 Lubrication chamber 37 Lubricating medium 38 Sealing lacquer 39 Positioning notch 40 weld seam 41 Sleeve 42 plain bearings 43 Sliding bearing rear wall F FV Spring preload force F S Tension F L lip pressure α Mounting cone angle
Claims
Radial shaft seal for sealing a rotating shaft (3) extending from a pressure chamber (1) of a working housing (2) filled with a fluid medium against an external space (4), the atmosphere, with a sealing housing (5) arranged in the working housing (2) having a rear wall (6) and a shaft passage bore (7a) arranged in this rear wall (6), wherein at least one elastomer sealing element (8) with an elastomer sealing lip (10) arranged on the pressure chamber side is arranged in the sealing housing (5) such that this elastomer sealing lip (10) bears directly against the shaft (3) or a running sleeve (12) arranged on the shaft (3) in a rotationally fixed manner, wherein the elastomer sealing element (8) is positioned exactly relative to the sealing housing (5) by means of a metallic support body (13) provided with an annular shaft passage bore (7b), characterized in that- that a support body fixing collar (15) with a support body fixing cylinder (16) is arranged on the outer edge of the support body (13) on the sealing housing side, wherein the outer diameter of the support body fixing cylinder (16) has an interference with the inner diameter of the associated inner wall (17) of the sealing housing (5), so that the support body (13), which in the final assembly state is press-fitted with its support body fixing cylinder (16) inside the sealing housing (5), and - that the support body (13) is provided with a support body web (18) extending radially to the support body fixing collar (15), and a support body positioning cylinder (21) with a support body positioning cylinder outer shell (22) is arranged inside the support body web (18) of the support body (13), and - that the support body positioning cylinder (21) is adjacent to the pressure chamber side, between the pressure chamber-side end of the support body positioning cylinder (21) and the free,a support collar (19) tapering towards the pressure chamber (1), i.e. towards the shaft passage (7b), is arranged on the support body positioning cylinder (21) at the end of the support body (1) provided with a shaft passage (7b), and having a support collar edge (20) at its free end on the pressure chamber side with the shaft passage (7b) in the support body (13), and that the elastomer sealing body (8) has a sealing body positioning cylinder (27) which bears against the support body web (18) on the outside side with its end face (28) and which is radially clamped with its inner shell (30) against the outer shell (22) of the support body positioning cylinder and with its outer shell (29) radially against the inner wall (17) of the sealing housing (5), and that on the sealing body positioning cylinder (27) of the elastomer sealing body (8) on the pressure chamber side a clamping positioning ring (23) is arranged which is connected to a clamping positioning ring (23) inside,The positioning ridge (24) arranged on the shaft side engages in an annular clearance (31) arranged on the pressure chamber side of the sealing body positioning cylinder (27) of the elastomer sealing body (8), which runs parallel to the support body positioning cylinder (21) and extends into the elastomer sealing body (8) up to above the support body positioning cylinder (21) and thereby forms a preload sealing ridge (26) on the elastomer sealing body (8) that abuts the support body positioning cylinder (21) on which the elastomer sealing lip (10) is arranged on the pressure chamber side, and that a clamping ring fixing cylinder (25) is arranged on the outside of the clamping positioning ring (23), i.e. opposite the positioning ridge (24) on the housing side, the outer diameter of which has an interference with the inner diameter of the associated inner wall (17) of the sealing housing (5), so that this too is joined inside the sealing housing (5) by means of an interference fit in the final assembly state,and- that the preload sealing web (26) of the elastomer sealing body (8) bears against the outer shell (22) of the support body positioning cylinder (21), and- that a freely supporting tensioning arch web (32) is arranged on the preload sealing web (26) in the area above the support collar (19), which transitions above the edge of the support collar (20) into a similarly freely supporting arch web (33), on which the elastomer sealing lip (10) is then arranged on the pressure chamber side, which bears against the shaft (3) or against a running sleeve (12) arranged rotationally fixed on the shaft (3), and- that an outer groove (34) is arranged above the support arch web (33) on the outer circumference of the elastomer sealing body (8), in which a cord spring (35) is arranged, which, in addition to the support arch web (33), also simultaneously secures the freely supporting tensioning arch web (32) of the preload elastomer sealing body (8),and thereby clamping the elastomer sealing lip (10) spring-elastically against the shaft (3) or the running sleeve (12) which is arranged non-rotatably on the shaft (3). Radial shaft seal according to claim 1, characterized in that a shaft passage bore (7a) is arranged in the working housing (2), to which a cylindrical countersink bore is arranged rotationally symmetrically, which directly forms the sealing housing (5) with its rear wall (6) with the shaft passage bore (7a) arranged in this rear wall (6). Radial shaft seal according to claim 1, characterized in that the sealing housing (5) with its rear wall (6) and a shaft passage bore (7a) arranged in this rear wall (6) is formed by a sleeve (41) made of metal or a cylindrical metal molded part, which is arranged as a separate component in a liquid-tight manner in a bore of the working housing (2). Radial shaft seal according to claim 3, characterized in that the radial shaft seal is arranged in the metallic sealing housing (5) arranged in the bore of the working housing (2), which is designed as a sleeve (41), a sliding bearing (42) is arranged adjacent to the pressure chamber side such that it axially abuts the clamping positioning ring (23), a sliding bearing rear wall (43) being arranged on this sliding bearing (41) on the pressure chamber side, against which the support body (13) of a further radial shaft seal according to claim 1 arranged in the sleeve (41) abuts axially. Radial shaft seal according to claim 3, characterized in that the metallic sealing housing (5), arranged in the working housing (2) and designed as a cylindrical metal forming part, is provided with a rear wall (6) and a shaft passage bore (7a) arranged in this rear wall (6), wherein in the region of the shaft passage bore (7a) on the rear wall (6) is a frustoconical sealing element contact collar (14) inclined towards the pressure chamber (1) at a contact cone angle (α) in the range of 25° to 38°, and in the sealing housing (5) on the pressure chamber side is the elastomeric sealing element (8) with its elastomeric sealing lip (10) and on the outer chamber side is a plastic sealing element (9) with PTFE and a plastic sealing lip (11) such that these sealing lips, the elastomeric sealing lip (10) as well as the plastic sealing lip (11), are directly on the shaft (3) or on a shaft (3). abuts / afts the rotationally fixed barrel sleeve (12),wherein the two sealing elements, the elastomer sealing element (8) and the plastic sealing element (9), are positioned in relation to the sealing housing (5) by means of a metallic support body (13) provided with an annular shaft passage bore (7b) such that the support body (13), which in the final assembly state is press-fitted inside the sealing housing (5) with its support body fixing cylinder (16), presses the plastic sealing element (9) against the rear wall (6) with its support body web (18) adjoining the support body fixing collar (15), and that a lubrication chamber (36) is arranged between the support body (13), the plastic sealing element (9) and the shaft (3) or the running sleeve (12), in which a lubricating medium (37) is arranged. Radial shaft seal according to one of claims 1 to 5, characterized in that the clamping ring fixing cylinder (25) of the clamping positioning ring (23) is also materially bonded to the sealing housing (5) in the press-fit state by means of one or more weld seams (40) arranged in the edge area between the sealing housing (5) and the clamping positioning ring (23). Radial shaft seal according to claim 6, characterized in that the weld seam(s) (40) arranged between the clamping positioning ring (23) and the sealing housing (5) is / are designed as a laser weld seam(s). Radial shaft seal according to one of claims 1 to 5, characterized in that, for the purpose of positive locking of the clamping ring fixing cylinder (25) of the clamping positioning ring (23) in the sealing housing (5), fixing cones are arranged on the circumference of the sealing housing (5), which are formed, for example, by positioning notches (39). Radial shaft seal according to claim 5, characterized in that a PTFE grease is arranged in the lubrication chamber (36) as the lubricating medium (37). Radial shaft seal according to one of claims 1 to 9 with a running sleeve (12) arranged non-rotatably on the shaft (3), characterized in that the running sleeve (12) is made of stainless steel and has a surface hardness greater than 1120 HV. Radial shaft seal according to claim 3, characterized in that sealing lacquer (38) is arranged circumferentially on the outer shell of the respective sealing housing (5), towards the working housing (2).