EP1738985B1 - Damping device for drawing and/or buffing devices of railway vehicles - Google Patents

Abstract

An elastomeric or mechanical damping mechanism (4) and a gas hydraulic damping mechanism (5) support a tappet (2) in a case (1). The damping mechanism (5) includes a cylindrical pressure chamber (9) that becomes smaller when a piston (7) is driven into the pressure chamber. An outlet (15) formed between the cylinder wall (6a) of the pressure chamber and the piston leads to a receiving chamber (10) through a duct (14). The portion of the piston introduced into the pressure chamber is cylindrical and exhibits a constant outside diameter.

Description

The invention relates to a damping device for tensile and / or impact devices on rail vehicles according to the preamble of claim 1.

Generic damping devices are used for example in buffers or couplings on rail vehicles.

So is out of the DE-A-196 19 214 a shock absorber known which is suitable for use in a buffer for rail vehicles. The shock absorber is equipped with a mechanical spring unit and a hydraulic damper. The mechanical spring unit is formed by a plurality of individual springs. The hydraulic damper consists of a pressure chamber arranged within a pressure chamber jacket, which is connected via radial throttle openings with a compensation chamber. In the pressure chamber, a piston is arranged, which is fastened by means of a screw to a bolt. The piston plunges during compression of the shock absorber in the pressure chamber and reduces it. As a result, a part of the damping fluid absorbed in the pressure chamber is displaced and conveyed via the radial throttle openings into the compensation chamber. Depending on the number, design and arrangement of the throttle openings, the throttle cross-section should be changeable according to the requirements.

From the EP-A 0 451 630 is a generic buffer known, which is intended for use in rail vehicles. For resilient support of a buffer plate, the buffer is provided with a gas-hydraulic damping device and an elastomeric spring arrangement. The gas-hydraulic damping device is provided with a cylindrical pressure chamber and a receiving chamber connected thereto via at least one channel. The pressure chamber decreases with increasing deflection of the buffer by a piston plunging into it. Between the piston and the inner circumference of the cylinder, an annular gap is formed. The piston is frontally provided with a recess which defines an annular wall which is elastically deformable depending on the internal pressure. By this design is to be achieved that the said gap between the piston and the inner circumference of the cylinder when increasing the liquid pressure in the cylinder remains approximately the same size or decreases, so that the damping effect does not deteriorate significantly even when increasing the liquid internal pressure.

Finally is from the DE-A-27 03 530 another, generic damping device known. This is provided with an outer buffer sleeve which engages around an inner buffer sleeve. Within the inner buffer sleeve an annular spring packet is arranged, which is supported by its ends on a respective pressure disk. The damping device further comprises a horizontally arranged hydraulic damper. This includes a bore provided with a damper housing having a filled with hydraulic fluid pressure chamber in the interior, in which a cylindrically shaped piston is immersed. The piston is connected via a piston rod to the one pressure disk. The pressure chamber is connected by means of overflow with a lying above the piston receiving space.

The invention aims to develop a damping device for tensile and / or impact devices on rail vehicles such that it consists of a few individual parts, is very simple and can be manufactured inexpensively.

For this purpose, according to the invention, a damping device for tensile and / or impact devices on rail vehicles according to claim 1 is provided.

Preferred embodiments of the invention are described in the dependent claims 2 to 16.

• Fig. 1 einen Längsschnitt durch einen überwiegend schematisch dargestellten Puffer;
• Fig. 2 einen Querschnitt durch den Puffer entlang der Linie A-A in Fig. 1.

A preferred embodiment of the invention will be explained in more detail with reference to drawings. Showing:

• Fig. 1 a longitudinal section through a buffer shown mainly schematically;
• Fig. 2 a cross section through the buffer along the line AA in Fig. 1 ,

In the Fig. 1 is shown in longitudinal section a buffer for rail vehicles, which is provided with an inventively designed damping device. The buffer shown in the unloaded resting state has a sleeve 1 (not shown) to be fastened to the rail vehicle and a slide 2 that is displaceable relative thereto. On the front of the plunger 2 a buffer plate 3 is welded. Both the sleeve 1 and the plunger 2 are formed substantially hollow cylindrical.

In the interior of the buffer, the damping device is arranged. The damping device comprises an elastomeric damping device in the form of a spring assembly 4 and a gas-hydraulic damping device 5. Although the two damping devices 4, 5 are physically arranged one behind the other, they function parallel to each other in functional terms and together serve the resilient support of the plunger 2 on the sleeve first The elastomeric spring assembly 4 consists of a plurality of elastomeric elements 4a, which are separated from each other by means of discs 4b. The individual spring elements 4a are lined up in succession on a piston 7, which is supported on the sleeve 1 at the vehicle end. The piston 7 has the shape of a bolt, which is integrally formed and preferably has a constant outer diameter and a smooth outer surface over its entire length. The front end of the piston 7 is provided with a chamfer in the form of a circumferential phase.

Both the elastomer elements 4a as well as the discs 4b are each provided with a bore whose diameter is matched to the outer diameter of the piston 7, so that the piston 7 simultaneously serves to position and support the elastomeric elements 4a. The discs 4b are held by the elastomeric members 4a so that they can not come into contact with the piston 7 and damage its surface.

The gas-hydraulic damping device 5 comprises a cylinder element 6, which is fixed to the rear side of the buffer plate 3. In order to ensure the correct position of the cylinder member 6 relative to the plunger 2, centering pins 20 are provided. In order to allow at an inclination of the buffer plate 3, for example, triggered by eccentrically acting on the buffer plate 3 compressive forces, a deflection or rolling of the cylinder member 6 relative to the buffer plate 3, there is a spherical support between the cylinder member 6 and the buffer plate 3. In particular Cylinder element 6 on the buffer plate 3 facing side provided with a spherical surface 31.

The cylinder element 6 is provided with a central pressure chamber 9 and a coaxially arranged, the pressure chamber 9 coaxially comprehensive receiving chamber 10 in the form of an annular space. On the outside of the cylinder element 6, an annular cover 8 is attached, which limits the receiving chamber 10 to the outside and seals. The pressure chamber 9 is cylindrical over about 90% of its length, the pressure chamber 9 in the opposite end of the immersion side of the piston 7, i. is provided in the region of its bottom 18, with a conically widening in diameter section 9a.

The pressure chamber 9 is completely filled with a hydraulic medium such as hydraulic oil, while the receiving chamber 10 is filled in the idle state shown here in majority with hydraulic medium and a gas under pressure. The extending between the cylinder element 6 and the receiving chamber 10 cylinder wall is provided with the reference numeral 6a. The wall thickness of the cylinder wall 6a increases toward the buffer plate 3. This overcompensates for the higher elasticity in the center of the cylinder and ensures that the annular gap area between the piston and the cylinder wall decreases over the stroke. This is intended to ensure that the pressure in the pressure chamber 9, despite a continuously decreasing immersion speed of the piston 7, is largely constant over a wide stroke range during dynamic compression of the plunger 2.

The recessed into the cylinder element 6 pressure chamber 9 is open on the side facing away from the buffer plate 3, wherein the piston 7 is guided into the pressure chamber 9 via this opening. On the opposite side of the opening, the pressure chamber 9 is bounded by the cylinder bottom 18. In the cylinder wall 6a of the cylinder member 6, two sealing rings 11 surrounding the piston 7 are embedded in the end region facing the vehicle. Between the piston 7 and the pressure chamber 9 comprehensive cylinder wall 6a is a passage in the form of an annular gap 15, which is not apparent from this illustration. The size of this annular gap 15 can be selected according to the requirements, wherein it preferably moves in the range of a few thousandths of a millimeter to a few hundredths of a millimeter. In addition, in the cylinder wall 6a of the cylinder member 6, an annular channel 13 is inserted, which is in communication with the annular gap 15. From this annular channel 13, a channel in the form of a bore 14 leads down into the receiving chamber 10. Between the annular channel 13 and the sealing rings 11 is a relief annular channel 16 in the cylinder wall 6a of the cylinder member 6 is inserted, which also has a radial relief hole 17 with the receiving chamber 10 communicates. In the region of the cylinder bottom 18, the cylinder member 6 is provided with a check valve 19 which connects the receiving chamber 10 with the pressure chamber 9 and allows backflow of hydraulic medium from the receiving chamber 10 into the pressure chamber 9, when the piston 7 during rebound of the buffer from the Retracts pressure chamber 9. Such a check valve 19 is preferably embedded on the underside in the cylinder wall 6a, 7 hydraulic medium is fed into the pressure chamber 9 during rebound of the piston.

With increasing deflection of the buffer -Einschieben the plunger 2-, the pressure chamber 9 is reduced by the plunging into them piston 7. So that the piston 7 can continue to dive into the pressure chamber 9, hydraulic medium must be displaced from the pressure chamber 9. The hydraulic medium flows through the annular gap 15 between the piston 7 and the cylinder wall 6a in the annular channel 13, from where it passes via the radially downwardly leading channel 14 into the pressure chamber 10. In addition or instead of an annular channel 15, an overflow channel could also be provided, via which the hydraulic medium can flow past the piston 7 into the annular channel 13. Such an overflow channel is preferably introduced on the upper side into the cylinder wall 6a, so that upon compression of the piston 7, the gas is first displaced and the pressure chamber 9 automatically vented.

The embodiment shown, in which the piston 7 is guided from the side facing away from the buffer plate 3 in the pressure chamber 9, has the further advantage that the hydraulic medium due to the inertia in a casserole at the cylinder bottom 18 collects, while small amounts of gas inadvertently in the pressure chamber 9 can get to collect at the end face of the piston 7. This ensures that the pressure chamber 9 vented independently at each impulse, since first the gas is displaced from the pressure chamber 9, which is particularly important for several successive casseroles of great importance. With a reverse arrangement, namely, the small amounts of gas would remain in the pressure chamber 9 and constantly multiply at several successive bumps, which would mean a large loss of energy absorption and damping capacity of the damping device and thus the whole buffer.

Since the piston 7 has a constant outer diameter and a smooth lateral surface, increases with increasing deflection of the plunger 2 of the throttle resistance in the piston 7 annular surrounding gap 15, whereby an increase in force is achieved via the insertion path. However, this increase in force is not only determined by the static cross section of the annular gap 15, but possibly also via an elastic extension of the cylinder member 6, the cylinder wall 6a has a tendency especially in a casserole to bulge material elastic in the radial direction to the outside, bringing itself at the same time the annular gap 15 would increase. This material-elastic expansion of the cylinder element 6 is influenced by the rigidity or wall thickness of the cylinder wall 6a, especially since the wall thickness of the cylinder wall 6a varies along the pressure chamber 9. Since the cylinder wall 6a is very stiff through the bottom of the cylinder 18 towards the end and is hardly any more radially deflectable, the pressure chamber 9 is provided in this end with the conically widening portion 9a. This section 9a is to ensure that in the extreme load case even against the stroke end sufficient hydraulic oil can flow past the piston 7.

Thus, the spring behavior of the gas-hydraulic damping device 5, and thus the entire buffer, depending on the mass to be delayed by the buffer and / or the insertion speed of the plunger 2 is changed.

The piston 7 is supported on its rear side not directly on the sleeve 1, but via an annular insert 22. While the sleeve 1 is preferably made of cast iron, the insert 22 is preferably made of a high-tempered steel. The annular insert 22 is provided with an oblique pressure surface 25 which at a corresponding annular surface on the rear wall 21 of the sleeve 1 rests. The insert 22 also has an extension 23 which has a spherical surface and a central through-bore 24. At this spherical surface, the piston 7 is supported with a corresponding pressure surface on its back. The piston 7 is also provided on its back with a piston extension 26 which projects into the recessed into the insert 22 bore 24. The outer diameter of the piston extension 26 is slightly smaller than the diameter of the inserted into the insert 22 bore 24, so that the piston 7 can be slightly deflected about the type of joint forming spherical surface of the insert 22 in the radial direction, which in the case of radially on the buffer plate 3 or ram 2 acting frictional forces is advantageous. At the end of the piston extension 26, a closure arrangement 27 is provided, which serves to close off a channel 28 leading through the piston 7 in the longitudinal direction. The closure assembly 27 is secured by unspecified means which are arranged in the bore 24 of the insert 22. Via the channel 28, the buffer can be filled after assembly with a gas and a hydraulic fluid.

The Fig. 2 shows a cross section through the buffer along the line AA in Fig. 1 , From this representation, in particular, the annular gap 15 between the piston 7 and the cylinder member 6 can be seen, which is shown exaggerated in this representation, however, for better visibility. In addition, a recessed into the sleeve 1 groove 29 can be seen, in which a arranged on the plunger 2 guide wedge 30 engages to define the position of the sleeve 1 relative to the plunger 2 in the circumferential direction and to prevent rotation of the plunger 2 relative to the sleeve 1 , Finally, four recessed in the rear wall 21 mounting holes can be seen, by means of which the sleeve 1 can be attached to a rail vehicle.

When a slow compression of the buffer results in a spring characteristic, which largely coincides with that of the elastomeric spring assembly 4, while dynamic compression additionally the dynamic behavior of the gas-hydraulic damping device 5 comes into play by the force increases faster in relation to the compression travel and a total higher level remains. Due to the size of the annular gap 15, the rigidity of the cylinder wall 6a and / or the possibly existing overflow channel together with the annular channel 13 and the bore 14 leading into the receiving chamber, the dynamic behavior can be influenced. In any case, the annular channel 14 surrounding the piston 7 is in the resting state of the buffer behind the end face of the piston 7, ie it is covered by the piston 7, so that from the beginning of the Einfedervorgangs to the gas-hydraulic damping device 5 is active by the displaced from the pressure chamber 9 hydraulic medium can flow only through the annular gap 15 in the annular channel 13 and the channel 14, which is associated with a corresponding throttling action.

The advantages of the described buffer are, in particular, that it consists of a few parts, has a simple structure and can be produced inexpensively. In this regard, for example, the piston 7 may be mentioned, which is integrally formed and has a constant outer diameter over its entire length. It is understood that such a piston 7 can be manufactured comparatively inexpensively. Of course, instead of or in addition to a spring arrangement consisting of elastomer elements, other spring arrangements such as, for example, mechanical spring arrangements or friction spring arrangements could also be used.

In addition to the use in buffers designed according to the invention damping devices, for example, for use in clutches on rail vehicles.

Claims (16)

1. Damping apparatus for pulling devices and/or shock absorption devices on rail vehicles, having a sleeve (1) and having a plunger (2) which can be moved relatively thereto, having an elastomeric and/or mechanical damping device (4) and having a gas-hydraulic damping device (5) for sprung assistance to the plunger (2) on the sleeve (1), with the gas-hydraulic damping device (5) being provided with a cylindrical pressure chamber (9) and a receiving chamber (10) which is connected thereto via at least one channel (14) and with the pressure chamber (9) being reduced in size by a piston (7) which enters it when loaded in the shock direction, and with at least one passage being formed between the piston (7) and a cylinder wall (6a) which bounds the pressure chamber (9), which passage is connected to the at least one channel (14) which leads into the receiving chamber (10), characterized in that the majority of that part of the piston (7) which can enter the pressure chamber (9) is cylindrical and has a continuously constant external diameter, and in that the piston (7) is at the same time intended for positioning of and assistance to the elastomeric and/or mechanical damping device (5).
2. Damping apparatus according to Claim 1, characterized in that at least that part of the piston (7) which can enter the pressure chamber (9) is provided with a smooth casing surface.
3. Damping apparatus according to Claim 1 or 2, characterized in that the pressure chamber (9) is provided in the end area opposite the end where the piston (7) enters with a section (9a) in which the diameter widens or increases.
4. Damping apparatus according to Claim 3, characterized in that the section (9a) in which the diameter widens or increases has an axial length which corresponds to a maximum of 25% of the piston diameter.
5. Damping apparatus according to one of the preceding claims, characterized in that the pressure chamber (9) is cylindrical over at least 75% of its length.
6. Damping apparatus according to one of the preceding claims, characterized in that the cylinder wall (6a) which bounds the pressure chamber (9) can be deflected elastically outwards in the radial direction as a function of the speed of the piston (7) as it enters the pressure area (9) in such a way that the cross section of the at least one passage between the piston (7) and the cylinder wall (6a) which bounds the pressure chamber (9) is enlarged.
7. Damping apparatus according to one of the preceding claims, characterized in that the wall thickness of the cylinder wall (6a) which bounds the pressure chamber (9) varies at least along the cylindrical section such that, when the plunger (2) springs in dynamically, the pressure in the pressure chamber (9) is largely constant over a wide stroke range, despite the speed at which the piston (7) enters it decreasing continuously.
8. Damping apparatus according to one of the preceding claims, characterized in that the passage between the piston (7) and the cylinder wall (6a) which bounds the pressure chamber (9) is in the form of an annular gap (15) and/or an overflow channel which are/is connected to the at least one channel (14) which leads into the receiving chamber (10).
9. Damping apparatus according to one of the preceding claims, characterized in that the at least one channel (14) is connected to an annular channel (13) which radially surrounds the piston (7).
10. Damping apparatus according to one of the preceding claims, characterized in that the piston (7) is in the form of a bolt, is formed integrally and has a constant external diameter over its entire length.
11. Damping apparatus according to one of the preceding claims, characterized in that at least one sealing element (11) which surrounds the piston (7) is incorporated in the cylinder wall (6a) which bounds the pressure chamber (9), and in that a further relief channel (16), which radially surrounds the piston (7), is arranged between the sealing element (11) and the annular channel (13) which radially surrounds the piston (7), and this relief channel (16) is connected to the receiving chamber (10) by a bore (17).
12. Damping apparatus according to one of the preceding claims, characterized in that the piston (7) is supported on the rear face facing the vehicle on an insert (22) which is provided with a spherical surface (23), such that it can be pivoted in the radial direction along the spherical surface (23).
13. Damping apparatus according to Claim 9, characterized in that the cylinder element (6) is fixed on the rear face of the buffer head (3) and in that the mechanical and/or elastomeric damper arrangement (4) is clamped in between the insert (22) in the end face of the cylinder element (6).
14. Damping apparatus according to Claim 13, characterized in that the pressure chamber (9) which is incorporated in the cylinder element (6) is open on the side facing away from the buffer head (3) and the piston (7) is inserted into the pressure chamber (9) via the opening formed in this way.
15. Damping apparatus according to Claim 14, characterized in that the annular channel (13) which radially surrounds the piston (7) is arranged behind the end surface of the piston (7) when the buffer is in the rest state, and is covered by the piston (7).
16. Damping apparatus according to one of the preceding claims, characterized in that a non-return valve (19) is arranged between the pressure chamber (9) and the receiving chamber (10) and allows hydraulic fluid to flow back from the receiving chamber (10) into the pressure chamber (9) while the piston (7) is moving out of the pressure chamber (9).

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