Pressure medium-operated brake cylinders for rail vehicles

Abstract

The invention relates to a pressure medium-operated brake cylinder for a rail vehicle, the brake cylinder comprising a housing (2); a translationally movable brake piston rod (4) extending through a hole (23) in a housing bottom (21); a guide ring received in the hole (23) and surrounding the brake piston rod (4) for guiding the brake piston rod (4) in the hole (23); and at least one sealing ring received in the hole (23) and surrounding the brake piston rod (4) for sealing an interior space (25) of the housing (2) relative to a space outside the housing (2), wherein the guide ring and the at least one sealing ring are constructed as a guide and sealing ring (3) integrated into a structural unit.

Description

Technical Field

[0001] The invention relates to a pressure medium-actuated brake cylinder for a rail vehicle. Background Art

[0002] Such pressure medium-actuated brake cylinders are used, for example, as parking brake cylinders in rail vehicles.

[0003] In order to seal the brake piston rod of the brake cylinder, which is guided through a hole in the housing bottom of the housing of the brake cylinder and can be moved translationally in the axial direction of the brake piston rod, a shaft sealing ring is usually used, which seals the area of ​​the interior space of the housing relative to the space outside the housing.

[0004] Furthermore, it is important to guide the brake piston rod exactly coaxially to the sealing ring in order to secure the sealing ring. It is important that the bearing of the brake piston rod has only enough play so that the sealing lip of the sealing ring can follow the radial movement of the brake piston rod without the sealing lip coming loose from the circumference of the brake piston rod. In order to guide such a brake piston rod exactly, it is therefore known to arrange a guide ring in the region of the opening of the housing in addition to the sealing ring, which guide ring slides on the brake piston rod. Summary of the invention

[0005] The object of the present invention is to further improve a pressure medium-actuated brake cylinder of a rail vehicle in such a way that cost-effective sealing and guidance of the brake piston rod is provided.

[0006] This object is achieved by a pressure medium-actuated brake cylinder for a rail vehicle having the features of the invention.

[0007] A pressure medium-operated brake cylinder for a rail vehicle comprises a housing; a translationally movable brake piston rod extending through a hole in the bottom of the housing; a guide ring accommodated in the hole and surrounding the brake piston rod for guiding the brake piston rod in the hole; and at least one sealing ring accommodated in the hole and surrounding the brake piston rod for sealing the interior space of the housing relative to the space outside the housing.

[0008] In this case, the guide ring and the at least one sealing ring are designed as guide and sealing rings which are integrated into one structural unit.

[0009] By means of a guide and sealing ring designed in this way, reliable guidance and sealing of the bore of the housing through which the brake piston rod is guided is ensured while simultaneously simplifying assembly.

[0010] According to an advantageous embodiment variant, the guide and sealing ring has a central guide region, to which sealing regions adjoin on both sides, as viewed in the axial direction of the brake piston rod.

[0011] A reliable seal is achieved by the centrally arranged guide region, in particular by virtue of the fact that the sealing region arranged adjacent to the guide region only compensates for very small gaps and is therefore always in reliable contact with the circumferential surface of the brake piston rod.

[0012] According to a preferred embodiment variant, each sealing ring has a sealing lip which bears against the circumferential surface of the brake piston rod.

[0013] According to an advantageous further development, a spring element, in particular a tension spring, is arranged on the side of each of the sealing areas facing away from the circumferential surface of the brake piston rod.

[0014] This ensures in a simple manner that the sealing area, in particular the sealing lip, is additionally pressed against the circumference of the brake piston rod.

[0015] According to an advantageous embodiment variant, the sealing lip is made of an acrylonitrile-butadiene rubber elastomer having a glass temperature below -60°C.

[0016] This enables gas-tightness down to temperatures of −50° C. and thus also enables the use of such brake cylinders at extremely low temperatures.

[0017] According to a further preferred embodiment variant, the guide region of the guide and sealing ring has a metal insert.

[0018] According to an advantageous further development, the metal insert is surrounded by the material of the sealing lip at least on three sides and is thus held in a secure manner in the guide and sealing ring.

[0019] In a preferred further development, the metal insert has a groove on its side facing the brake piston rod, into which groove a guide strip made of a slidable material is inserted.

[0020] This makes it possible to dispense with additional lubricant for the translational movement of the brake piston rod relative to the guide and sealing ring.

[0021] According to a preferred further development, the guide strip consists of polytetrafluoroethylene (PTFE) having a carbon content of 20% to 30%, particularly preferably of approximately 25%.

[0022] This material mixture has been shown in experiments to be of high quality with regard to guidance, friction and wear.

[0023] The metal insert is preferably made of steel.

[0024] The metal insert is preferably designed as a ring which completely surrounds the guide strip from the outside in radial direction.

[0025] The guide strip itself is preferably also designed in annular form, particularly preferably as an open ring with at least one recess, which firstly facilitates the installation of the guide strip in the metal insert and secondly thereby provides a collecting groove for wear of the guide strip.

[0026] According to an alternative embodiment variant, the metal insert is completely surrounded by the material of the sealing lip.

[0027] According to a preferred further development of this embodiment variant, the material of the sealing lip arranged radially inwardly before the metal insert has a circumferential lubricant groove.

[0028] By aligning the lubricant groove in the circumferential direction, lifting of the sealing lip due to compression of the relatively soft material of the sealing lip in the direction of the sealing lip is avoided.

[0029] According to another alternative embodiment variant, the metal insert consists of bearing bronze, the inner surface of the metal insert consisting of bearing bronze rests on the brake piston rod.

[0030] Here too, in a preferred embodiment variant, the contact surface of the metal insert has a circumferential lubricant groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the accompanying drawings:

[0032] Figure 1 A sectional view of a partial region of an embodiment variant of a brake cylinder according to the invention is shown, the brake cylinder having a guide and sealing ring arranged in a bore of a housing, which surrounds a brake piston rod,

[0033] Figure 2 shows a top view of a cut-away guide and sealing ring according to a first embodiment variant,

[0034] Figure 3 Show according to Figure 3 Another sectional view of a guide and sealing ring with a brake piston rod accommodated therein,

[0035] Figure 4 An alternative embodiment variant of the guide and sealing ring is shown corresponding to Figure 2 , and

[0036] Figure 5 Another embodiment variant of the guide and sealing ring is shown corresponding to Figure 2 and Figure 4 of the view.

[0037] Figure 6The figure shows a further embodiment variant of the guide and sealing ring. DETAILED DESCRIPTION

[0038] In the following description of the figures, terms such as top, bottom, left, right, front and rear etc. refer only to selected exemplary representations and positions of brake cylinders, housings, guide and sealing rings, sealing lips, metal inserts, guide strips and the like in the respective figures. These terms are to be understood in an unrestricted manner, i.e. these relationships can be changed by different operating positions or mirror-symmetrical designs or the like.

[0039] exist Figure 1 In the drawing, reference numeral 2 denotes a housing of a brake cylinder according to the invention, for example a parking brake cylinder, in one embodiment variant.

[0040] In the interior space 25 of the housing 2, which is delimited by the cylinder wall 22 and the housing bottom 21 and here, for example, by the spring-energy brake piston 6, the brake piston rod 4 is centrally arranged and accommodated in a hole 23 in the housing bottom 21 on the side of the housing 2 facing away from the spring-energy brake piston 6.

[0041] On the side of the spring-energy brake piston 6 facing away from the interior space 25, a spring 5 is shown, with which the spring-energy brake piston 6 can be pressed in the direction of the bottom 29. When the interior space 25 is charged with compressed air, the spring-energy brake piston 6 is pressed and the brake piston rod 4 is pressed back from the braking position into the release position by means of the spring-energy brake piston when the brake cylinder is used in a parking brake unit.

[0042] In order to seal the spring-energy brake piston 6 relative to the interior 25 of the housing 2 , a sealing ring 7 is arranged radially on the outside of the spring-energy brake piston 6 .

[0043] If further Figure 1 It can be seen in FIG. 2 that a recess 24 is provided in the opening 23 in the housing bottom 21 , in which recess the guide and sealing ring 3 is arranged.

[0044] A first embodiment variant of this guide and sealing ring 3 is Figure 2 and 3 It is shown in FIG. 2 that, with this guide and sealing ring, the interior space 25 can be sealed off from the exterior space opposite the housing bottom 21 and at the same time serve to radially guide the brake piston rod 4 .

[0045] As in Figure 2 and Figure 3 As shown in FIG, such a guide and sealing ring 3 integrated into a structural unit has a central guide region 31 to which sealing regions 32 adjoin on both sides, viewed in the axial direction of the brake piston rod 4 .

[0046] In this case, each of the sealing areas 32 has a sealing lip 34 which bears against the circumferential surface 41 of the brake piston rod 4, as shown by way of example in FIG. Figure 4 As shown in .

[0047] In order that the sealing lip 34 always presses against the circumferential surface 41 of the brake piston rod 4 , in the embodiment variant shown here a spring element, in particular a tension spring in terms of design, is arranged on the side of each of the sealing areas 32 facing away from the circumferential surface 41 of the brake piston rod 4 .

[0048] The tension spring 10 surrounds the (circular) cylindrical outer wall of the sealing area 32 , wherein the tension spring 10 is prestressed when mounted on the sealing area 32 and thus presses the sealing lip 34 against the circumferential surface 41 of the brake piston rod 4 .

[0049] The sealing lip 34 is preferably designed in its shape so that it Figure 2 and Figure 3 As can be clearly seen in FIG. 3 , starting from the guide region 31 , the sealing lip 34 tapers axially outwardly toward the brake piston rod 4 with a smaller slope than on the side of the sealing lip 34 facing away from the guide region 31 .

[0050] exist Figures 2 to 5 In each of the embodiment variants shown in FIG. 1 , the guide region 31 of the guide and sealing ring 3 has a metal insert 9 , 11 , 12 .

[0051] exist Figures 2 to 3 and Figure 5 In the embodiment variant shown in FIG, the metal inserts 9 , 12 are surrounded on three sides by the material of the sealing lip 34 .

[0052] The material of the sealing lip 34 extends here radially outwards from the actual sealing region 32 with the sealing lip 34 in an approximately pocket-like manner and thus surrounds the metal inserts 9 , 12 .

[0053] In the central guide area 31 of the guide and sealing ring 3, Figure 2 and Figure 3 In the embodiment variant shown in FIG. 1 , the metal insert 9 has a groove 91 on its side facing the brake piston rod 4 , into which groove a guide strip 8 made of a slidable material is inserted.

[0054] In this case, a possible slidable material is in particular polytetrafluoroethylene (PTFE) having a carbon content of 20% to 30%, in particular approximately 25%. Other slidable materials are also conceivable.

[0055] The metal insert 9 is preferably made of steel and thus, together with the guide strip 8 , ensures a secure radial guidance of the brake piston rod 4 .

[0056] The sealing lip 34 and the sealing area 32 adjoining it are preferably made of an acrylonitrile-butadiene rubber (NBR) elastomer, preferably a cold-resistant NBR80 elastomer, which is characterized by a glass temperature below -60°C and thus ensures gas tightness at temperatures down to -50°C.

[0057] The guide strip 8 is preferably designed as a ring which is open in one section, wherein the cutouts 81 of the guide strip 8 are designed at an angle, preferably at an angle of approximately 30°, when viewed axially in the direction of the brake piston rod 4 .

[0058] exist Figure 6 In the embodiment variant shown in , instead of the metal insert 9 made of steel with the guide strip 8 accommodated therein, a metal insert 12 is made of bearing bronze, wherein the side of the metal insert 12 facing the brake piston rod 4 functionally rests directly on the circumferential surface 41 of the brake piston rod 4.

[0059] In the preferred embodiment variant shown here, the contact surface of the metal insert 12 has a circumferential lubricant groove 13, which extends between contact strips 14 that remain as bearing surfaces, wherein the contact strips 14 contact the circumferential surface 41 of the brake piston rod 4 when the guide and sealing ring 3 is installed.

[0060] exist Figure 5 In the embodiment variant shown in FIG. 1 , the metal insert 11 is completely surrounded by the material of the sealing lip 34 .

[0061] The metal insert 11 , which is preferably also made of steel, can therefore not come into contact with the brake piston rod 4 .

[0062] Here, in order to prevent the sealing lip 34 from detaching due to material displacement when the guide area of ​​the sealing lip 34 material is abutted, it is also preferred to provide a lubricant groove 13 in the material of the sealing lip 34 which is radially inner and surrounds the metal insert 11, and the sealing lip has an abutment strip 14 between which it abuts against the brake piston rod 4, so that any material displacement that may occur in the area of ​​the guide area 31 extends into the lubricant groove 13 and thus effectively avoids displacement or bulging of the sealing lip 34.

[0063] Reference numerals list

[0064] 2 Housing

[0065] 21 Shell bottom

[0066] 22 Cylinder wall

[0067] 23 holes

[0068] 24 Gap

[0069] 25 Interior Space

[0070] 3 Guide and sealing rings

[0071] 31 Guide area

[0072] 32 Sealing area

[0073] 33 Circumference

[0074] 34 Sealing lip

[0075] 4 Brake piston rod

[0076] 41 Circumference

[0077] 5 Spring

[0078] 6 Spring-energized brake piston

[0079] 7 Sealing ring

[0080] 8 Guide belt

[0081] 9 Metal inserts

[0082] 10 tension spring

[0083] 11 Metal inserts

[0084] 12 Metal inserts

[0085] 13 Lubricant groove

[0086] 14 Sticking strip

Claims

1. A pressure medium-actuated brake cylinder for a rail vehicle, the brake cylinder comprising: Housing (2); a translationally movable brake piston rod (4) extending through a hole (23) in the housing bottom (21), a guide ring which is received in the hole (23) and surrounds the brake piston rod (4) and is used for guiding the brake piston rod (4) in the hole (23); at least one sealing ring received in the bore (23) and surrounding the brake piston rod (4) for sealing the interior space (25) of the housing (2) relative to the space outside the housing (2), It is characterized in that The guide ring and the at least one sealing ring are constructed as a guide and sealing ring (3) integrated into a structural unit, the guide and sealing ring (3) having a guide area (31) in the center, and a sealing area (32) connected to the guide area on both sides when viewed in the axial direction of the brake piston rod (4), the guide area (31) of the guide and sealing ring (3) having a metal insert (9, 11, 12), the metal insert (9, 11, 12) being surrounded by the material of the sealing lip (34) on at least three sides, and the metal insert having a groove (91) on its side facing the brake piston rod (4), in which a guide strip (8) made of a slidable material is inserted.

2. The brake cylinder according to claim 1, characterized in that: Each of the sealing areas (32) has a sealing lip (34) which bears against a circumferential surface (41) of the brake piston rod (4).

3. The brake cylinder according to claim 2, characterized in that: A spring element is arranged on the side of the circumferential surface (41) of each of the sealing areas (32) facing away from the brake piston rod (4).

4. The brake cylinder according to any one of claims 1 to 3, characterized in that: The sealing lip (34) is made of acrylonitrile-butadiene rubber elastomer with a glass temperature lower than -60°C.

5. The brake cylinder according to claim 1, characterized in that: The guide belt (8) is made of polytetrafluoroethylene with a carbon content of 20% to 30%.

6. The brake cylinder according to claim 1, characterized in that: The metal insert is made of steel.

7. The brake cylinder according to claim 1, characterized in that: The metal insert is designed as a ring which completely surrounds the guide strip (8) from the outside in radial direction.

8. The brake cylinder according to claim 1, characterized in that: The metal insert is completely surrounded by the material of the sealing lip (34).

9. The brake cylinder according to claim 8, characterized in that: A sliding surface arranged radially inwardly upstream of the metal insert and made of the material of the sealing lip (34) has a circumferential lubricant groove (13).

10. The brake cylinder according to claim 1, characterized in that: The inner surface of the metal insert made of bearing bronze rests on the brake piston rod (4).

11. The brake cylinder according to claim 10, characterized in that: The contact surface of the metal insert has a circumferential lubricant groove (13).

12. The brake cylinder according to claim 3, characterized in that: The spring element is a tension spring (10).

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