DE202015004304U1 - Device for damping compressive forces with adapted throttle mandrel - Google Patents

Abstract

Device (100) for damping pressure forces, the device (100) comprising: - a cylinder (10), in particular a circular cylinder, in which a hydraulic chamber (11) is formed; - A relative to the cylinder (10) telescopically along a central axis (1) displaceable hollow piston (20); - A formed at one end portion of the hollow piston (20) valve assembly (40) for dividing the hydraulic chamber (11) in a rear hydraulic chamber portion (12) and a front hydraulic chamber portion (13); - A in the hollow piston (20) along the central axis (1) movably arranged separating piston (25) which separates a within the hollow piston (20) formed gas space (21) from the front hydraulic chamber portion (13), wherein the valve assembly (40) having a the overflow region (41) connected to the rear hydraulic chamber region (12) and an eccentric hydraulic chamber (43) connected to the overflow region (41) via at least one channel (42), - a throttle mandrel (30), the front side of the cylinder (10) within the rear hydraulic chamber portion (12) is arranged so that it is immersed in the overflow region (41), characterized in that the throttle mandrel (30) has a tip (33) which tapers to the overflow region (41) facing side ,

Description

The present invention relates to a device for damping compressive forces in the form of a reversible designed even with dynamic shock load shock protection.

From rail vehicle technology, it is known between the individual car bodies of a multi-unit vehicle shock protection, z. B. in the form of so-called bumpers to use. These components are designed to absorb energy in the event of a collision with a fixed or a movable obstacle, such as another car body, thereby preventing damage to the vehicle or the load. Such bumpers are mainly used on rail vehicles, wherein usually one or two attached to the end faces construction parts are used, which have the purpose to absorb the horizontal force acting on the rail vehicle in the longitudinal direction from the outside pressure forces.

Essentially, two types of bumpers are used on rail vehicles. So-called central buffer represent a shock absorber, which is arranged in the longitudinal axis of the vehicle, so that there is only one buffer in the middle of the head threshold on each end face of the rail vehicle. Furthermore, so-called page buffer are known in which two buffers are located on the front side of the rail vehicle.

From rail vehicle technology is known, for example, in a multi-unit rail vehicle, the individual car bodies with side buffers (also called "UIC buffers") equip, especially if the car bodies are not connected to each other via a bogie and thus in driving the distance between two mutually coupled car bodies can vary. Such page buffers serve to absorb and dampen the shocks occurring during normal driving, for example during braking.

In order to achieve both a good compression behavior of the buffer in quasi-static compression and under dynamic stress, it is known to use so-called gas-hydraulic damping devices, which consist of a combination of a gas spring with a hydraulic overflow system. In static or quasi-static compression of such a conventional gas-hydraulic buffer, gas, typically nitrogen, is compressed within the gas spring portion of the buffer, creating a drag on a buffer plate connected to the buffer. As the force acting on the outside of the buffer decreases, the gas spring thus effects the so-called return stroke, that is, re-expansion of the buffer, by subsequent expansion of the gas.

In dynamic stress of such a conventional gas-hydraulic damper additionally through a throttle gap flowing hydraulic oil or other hydraulic fluid ensures that a dynamic force curve following a hydraulic counterforce is generated by the pressure drop occurring during the flow process over the throttle gap, which acts against the compression effecting impact force , In such gas-hydraulic damper combinations, it is desirable to allow an overflow of the hydraulic fluid through the throttle gap against the pressure of the gas spring only when a certain minimum force is exceeded during compression to not diminish the proportion of the gas spring to the overall suspension, especially in the static load case ,

It is therefore known to provide so-called multiplier valves, which are arranged in such a way that the larger effective area of the multiplier valve ("multiplier area") acts directly or indirectly on the pressure prevailing in the gas space of the gas spring and such a multiplier valve is actuated by this directly or indirectly acting gas pressure his valve seat is pressed. The smaller effective area of the multiplier valve, d. H. on the opposite side, is then in operative connection with the hydraulic portion of the conventional gas-hydraulic damper. Only when - for example, as a result of a quasi-static deflection of the buffer by a shock - the pressure in the hydraulic fluid is a multiple, for example, five times the gas pressure, this high pressure is able by acting on the small effective surface of the multiplier this far as from his Move seat, that a passage gap is released, through which the hydraulic fluid can flow, for example, in a hydraulic reservoir. By using such a multiplier valve is thus achieved in particular that the gas pressure in the gas space of the gas spring can be kept relatively low at fully ausgefedertem buffer. This makes it possible to obtain a favorable static characteristic of the gas spring portion of the gas-hydraulic damping device.

The combination of a hydraulic throttle device, for example in the form of a throttle mandrel with such a multiplier valve leads to a relatively bulky design in the known buffer arrangements, since the throttle mandrel is arranged on a center axis of the buffer cylinder and the multiplier valve completely surrounds the overflow behind the throttle mandrel, to a accordingly size Thus, the volume of the multiplier valve must be significantly greater than the overflow area in which the hydraulic fluid flows from the rear hydraulic chamber via the throttle gap formed by the throttle mandrel.

As a result, a multiplier valve must be provided in the conventional device, which requires a large amount of material due to its large volume of construction and also difficult to construct.

From the EP 2 535 237 A1 a device is known, which shows the combination of a throttle device, for example in the form of a throttle mandrel with a multiplier valve.

The device for damping compressive forces, which has a valve arrangement with an overflow region formed in an end region of a hollow piston, comprises a multiplier valve, which closes an eccentrically arranged hydraulic chamber connected to the overflow region via at least one channel with its rear effective surface (input surface), wherein the multiplier valve in turn, is arranged eccentrically with respect to the center axis of the hollow piston.

The hollow piston of the device is telescopically displaceable relative to a cylinder receiving it along the center axis thereof, wherein the valve arrangement at the end portion of the hollow piston serves to divide a hydraulic chamber formed in the receiving cylinder into a rear hydraulic chamber portion and a front hydraulic chamber portion. In the hollow piston, a gas space is further formed at its end opposite the valve arrangement, which is separated by a separating piston from the front hydraulic chamber area. The separating piston is also movably arranged along the center axis.

During compression, d. H. upon insertion of the hollow piston into the cylinder, for example as a result of a shock, the hydraulic fluid in the rear hydraulic chamber is pressurized and consequently flows into the overflow region of the valve assembly and from there via the at least one channel into the eccentric hydraulic chamber on the input side of the multiplier valve. In this case, the same pressure then prevails in the rear hydraulic chamber, in the overflow area and in the eccentric hydraulic space.

In the front hydraulic chamber area, d. H. in the likewise filled with hydraulic fluid space between the separating piston and the output surface of the multiplier valve prevails due to the free movement of the separating piston, the same pressure as within the gas space on the other side of the separating piston. When the pressure in the eccentric hydraulic space at the input side of the multiplier valve multiplied by the design factor of the multiplier valve exceeds the pressure in the front hydraulic chamber, that is, the pressure in the eccentric hydraulic chamber. H. If this pressure prevailing in the eccentric hydraulic space is high enough to push the multiplier valve out of its valve seat against the pressure prevailing in the front hydraulic chamber, a passage gap arises at the multiplier valve, through which hydraulic fluid from the eccentric hydraulic chamber, i. H. So also from the rear hydraulic chamber in the front hydraulic chamber can flow. As a result of the space-demanding process, the separating piston moves further into the gas space and compresses the gas contained therein.

By providing the eccentric hydraulic space in addition to the overflow region, it is thus possible to arrange the multiplier valve eccentrically such that it does not have to surround the overflow region itself. This achieves a significant reduction in the volume of the multiplier valve, which also simplifies its design. The eccentric arrangement of the multiplier valve in the valve assembly results in addition to the simple and inexpensive construction of the further advantage of being able to provide a throttle mandrel on the device for damping compressive forces without the use of the multiplier valve would lead to a bulky design. It follows as a consequence that the total length of the damping device does not have to be increased due to the very small space required.

In the described embodiment, it is also provided to fasten the one throttle mandrel to the cylinder in its center axis in such a way that this throttle mandrel projects into the overflow region of the valve arrangement. In this connection region between the rear hydraulic chamber and the overflow region, therefore, a throttle gap, usually an annular throttle gap is formed. Hydraulic fluid displaced from the rear hydraulic chamber thus flows through this throttle gap formed between the throttle mandrel and the overflow region, the resulting pressure drop primarily depending on the gap cross section. As a result, if the hollow piston penetrates further into the cylinder, the valve arrangement formed on the end region of the hollow piston also shifts further into the cylinder, as a result of which the throttle mandrel penetrates deeper into the overflow region of the valve arrangement. By a specially adapted shape of the throttle mandrel reduces the cross-section of the throttle gap during penetration of the Throttle mandrel, ie the gap cross section of the throttle gap is smaller, the deeper the throttle mandrel penetrates into the overflow region of the valve assembly.

By this constructive measure, the fact is taken into account that decreases during a shock absorption process by the damping device due to the energy absorption, the relative speed of the colliding vehicles over the time course of the impact process. During such a shock process, therefore, the braking speed of the vehicle masses also reduces the indentation speed, ie. H. the compression speed of the damper. In addition to the dependence on other variables, the hydraulic forces occurring as a function of the throttle gap cross-section and the Eindrückgeschwindigkeit, d. H. Desocking speed of the damping device describe. The fact that the throttle mandrel is formed by its shape to reduce the Drosselspaltquerschnittabhängig of its penetration into the overflow region of the valve assembly, can be kept largely constant by the decreasing during the Einfedervorganges speed at which the throttle mandrel penetrates into the overflow area, occurring hydraulic force , At the same time, the combination with the eccentrically arranged multiplier valve ensures that even in this case, the combination with a throttle mandrel, with a simple arrangement and low overall volume, results in a defined static characteristic of the damping device.

Furthermore, it is provided that the valve assembly further comprises a check valve, wherein the check valve is arranged such that it allows a return flow of the hydraulic fluid from the front hydraulic chamber portion in the overflow region and from the front hydraulic chamber portion in the rear hydraulic chamber area exactly when the pressure in the front hydraulic chamber area is greater than the pressure in the overflow area or the pressure in the rear hydraulic chamber area. By such a solution with a check valve, it is possible to regulate the rebounding of the damping device, the so-called return stroke, that this return stroke can be done quickly, without in case of load, so during compression by this return stroke a bypass option, ie a bypass option the hydraulic fluid from the overflow at the multiplier valve over would result in the front hydraulic chamber.

With regard to the gas space, it is provided that this is filled with a pressurized gas. This pressurized gas may in particular be nitrogen. By choosing the gas and its associated thermodynamic properties as well as with the choice of overpressure, the static characteristic of the device according to the invention for damping pressure forces can be influenced in an advantageous manner.

Furthermore, it is provided to provide the hollow piston with at least one hollow piston sealing element, said hollow piston sealing element is designed such that it ensures during the displacement of the hollow piston within the cylinder, a sealing of the inner space relative to the outer space.

Furthermore, it can also be provided to equip the separating piston with at least one separating piston sealing element, which, in addition to its sealing properties, ensures stripping of hydraulic fluid, for example by means of scraper rings, when the separating piston is displaced within the hollow piston. As a result, the gas within the gas space is affected as little as possible in its purity, which contributes to a better longevity of the device and can make it necessary to limit the operational compression travel of the device for damping compressive forces by a high bias of the gas spring component to to limit the jerk of the clutch devices loaded in a pulling direction in a sudden braking in such a way in the case of a deceleration of the push bandage of coupled tracked vehicles such that damage to the clutch devices such as, for example, tearing off of coupling hooks or the like can be avoided.

The object of the invention is to improve the absorption of the impact energy.

The solution of the problem is provided by the features of claim 1.

These measures ensure better functionality of the device. In order to improve the flow conditions when immersing the throttle mandrel in the overflow region, the side of the throttle mandrel facing the overflow region is now conical or conical instead of blunt. As a result, the throttle gap continuously decreases with increasing immersion of the throttle mandrel into the overflow region, and in this way enables substantially more effective damping of the impact energy impinging on the device.

An advantageous development provides that the length of the throttle mandrel can be made variable. For example, are shorter Designs of the device necessary, it is sufficient to replace the end face in the cylinder of the device insertable and fixable throttle mandrel by a shorter design. By provided on the front side of the cylinder bore of the dimensions adapted throttle mandrel is inserted without opening the device itself. As a result, independently of the series production individually a corresponding throttle mandrel can be selected and used.

Further advantageous embodiments will become apparent from the following description, the claims and the drawings.

Show it:

1 a perspective view of the inventive device for damping compressive forces;

2 a section through the device according to 1 ;

3 a section of an enlarged view of the valve assembly of the device together with the throttle mandrel according to 2 ,

1 shows a perspective view of the device according to the invention 100 , The device 100 includes a cylinder 10 and a hollow piston displaceable therein 20 , The device 100 is that of a buffer not described in detail, especially for rail vehicles.

2 shows a sectional view of an embodiment of the device 100 for damping compressive forces, which essentially consist of a cylinder 10 and one telescopically along a central axis 1 displaceably arranged hollow piston 20 , In an end region of the hollow piston is a valve assembly 40 arranged one within the cylinder 10 trained hydraulic chamber 11 in a rear hydraulic chamber area 12 and a front hydraulic chamber portion 13 divided. Thus, the hydraulic chamber extends 11 at least partially in the hollow piston 20 in; in other words, the front hydraulic chamber area 13 inside the hollow piston 20 educated.

A separating piston 25 separates the front hydraulic chamber area 13 from one inside the hollow piston 20 trained gas room 21 , where the gas space 21 via a filling valve 27 can be filled with pressurized gas. The separating piston 25 has separating piston sealing elements 26 on and is along the center axis 1 movably arranged. An increase in volume in the front hydraulic chamber area 13 , For example, by inflow of hydraulic fluid from the rear hydraulic chamber area 12 in the front hydraulic chamber area 13 , thus causing a displacement of the separating piston 25 in the gas space 21 into it, with the gas in the gas space 21 is compressed at the same time.

When moving the hollow piston 20 inside the cylinder 10 prevent first hollow piston sealing elements 22 and second hollow piston sealing elements 23 leakage of hydraulic fluid from the hydraulic chamber 11 at the gap between cylinders 10 and hollow piston 20 into the device 100 surrounding outdoor area. In particular, for example, by not shown scraper rings on the first Holkolben sealing element 22 and / or on the second hollow piston sealing element 23 ensures that essentially no hydraulic fluid, the surface of the currently not inserted into the cylinder outer area 24 the hollow piston wetted.

A throttle mandrel 30 is in the rear hydraulic chamber area 12 the hydraulic chamber 11 trained and in the center axis 1 attached to the cylinder. In the in 2 illustrated state of the device 100 is the throttle mandrel 30 in front of an overflow area 41 the valve assembly 40 arranged, which is suitable - depending on the impact energy acting from the outside on the device - in the overflow area 41 immerse. During immersion in the overflow area 41 forms between the throttle mandrel 30 and the overflow area 41 a throttle gap 31 out. Hydraulic fluid, which from the rear hydraulic chamber area 12 in the overflow area 41 flows through the pressure drop at the throat limiting throttle gap 31 throttled during the overflow. The overflow area 41 is designed by a sleeve-like training, the front side exclusively to the side of the throttle mandrel 30 is formed open. The opening is dimensioned in the diameter such that it is slightly larger than the diameter of the penetrating throttle mandrel 30 , In addition, the front side in the sleeve-like design, a further opening is provided, which is a fluid connection to the channel 42 provides.

The throttle mandrel 30 has a tip 33 in the mounted state on the overflow area 41 indicates, preferably formed cone-shaped. In principle, any shape is suitable that is not formed blunt. This tapered to overflow region in cross-sectional shape leads to a continuous change in the fluid flow in the throttle gap 31 , in particular in the immersion phase in the overflow area 41 ,

A special training of the throttle mandrel 30 is designed so that it is not integral with the cylinder 10 connected is. Much more becomes a detachable connection with the cylinder 10 proposed to different lengths L of the throttle mandrel 30 to be able to use. Different lengths are therefore needed to meet a given space requirements when used as a buffer. The throttle mandrel 30 is frontal (end of the cylinder 10 ) in a hole 70 insertable and fixable there. Preferably, the throttle mandrel 30 from the outside into the hole 70 and thus in the rear hydraulic chamber area 12 insertable. A sealing ring 71 seals the rear hydraulic chamber 12 from the environment.

The housing 45 the valve assembly 40 is with the end portion of the hollow piston 20 connected.

In a compression process of the device 100 becomes the hollow piston 20 by acting on external forces along the longitudinal axis representing the center axis 1 in the cylinder 10 moved into it. Accordingly, the moves on the Hohlkoben 20 attached valve assembly 40 further into the cylinder 10 , so the rear hydraulic chamber area 12 into it. This creates an overpressure in the rear hydraulic chamber area 12 and at low actuation speeds, ie in quasi-static compression, the same overpressure arises in the overflow region 41 the valve assembly. Over at least one channel 42 this overflow area 41 is an eccentrically arranged hydraulic chamber 43 (preferably in the formation of an annulus) with the overflow area 41 the valve assembly 40 connected so that even in this eccentric hydraulic space 43 in this quasistatic case, the same overpressure as in the rear hydraulic chamber area 12 the hydraulic chamber 11 is present. This eccentric hydraulic room 43 is by means of a multiplier valve 50 closed with its input side. On the output side of the multiplier valve 50 The pressure acting in the front hydraulic chamber area acts 13 the hydraulic chamber 11 prevails.

At sufficiently high pressure, ie at a correspondingly sufficient pressure ratio between the pressure in the eccentric hydraulic chamber 43 and the pressure in the front hydraulic chamber area 13 opens the multiplier valve 50 and allows overflow of hydraulic fluid from the overflow area 41 through the channel 42 and the eccentric hydraulic room 43 in the front hydraulic chamber area 13 ,

When hydraulic fluid flows in through the duct 42 in the eccentric hydraulic room 43 the pressure acts in the eccentric hydraulic chamber 43 on the rear effective area 52 ie the input area of the multiplier valve 50 , Is this on the rear effective area 52 acting pressure greater than that on the front effective area 51 of the multiplier valve 50 acting pressure multiplied by the design multiplication factor of the multiplier valve 50 so becomes the multiplier valve 50 pushed out of his seat and gives the passage gap 53 free.

A reset of the multiplier valve 50 is ensured, among other things, that in the rear valve chamber 54 of the multiplier valve 50 a relatively low pressure, namely the pressure corresponding to the ambient pressure during assembly, prevails, while during the closing operation of the multiplier valve on this the much higher pressure from the gas spring acts.

When opening the multiplier valve 50 the passage gap 53 is at least partially released, this leads to the overflow of the hydraulic fluid to a further pressure drop across this passage gap 53 in addition to the pressure drop in the throttle gap 31 , In particular, in a quasi-static actuation operation of the device 100 This leads to an effective static force-displacement characteristic of the device according to the invention 100 ,

To a Rückströmmöglichkeit the hydraulic fluid from the front hydraulic chamber area 13 in the rear hydraulic chamber area 12 during a return stroke of the hollow piston 20 to allow without an additional undesirable overflow in the pressure load case between the overflow 41 and the front hydraulic chamber portion 12 form, is a check valve 32 provided in the form of a ball valve, which has a Rückströmpfad the hydraulic fluid from the front hydraulic chamber area 13 in the rear hydraulic chamber area 12 allows and at the same time closes this additional pressure-transfer channel formed in the pressure load case. The invention is not limited to the embodiments described with reference to the accompanying drawings. Rather, appropriate modifications are conceivable. In addition, the invention is not limited only to such embodiments comprising a multiplier valve, as the embodiment shows.

LIST OF REFERENCE NUMBERS

1

mid-axis

10

Cylinder, in particular circular cylinder

11

hydraulic chamber

12

rear hydraulic chamber area of the hydraulic chamber

13

front hydraulic chamber portion of the hydraulic chamber

20

hollow piston

21

headspace

22

first hollow piston sealing element

23

second hollow piston sealing element

24

not inserted outer area of the hollow piston

25

separating piston

26

Separating piston seal element

27

filling valve

30

throttle Dorn

31

throttle gap

32

check valve

33

top

40

valve assembly

41

Overflow area of the valve arrangement

42

Channel of overflow area

43

eccentric hydraulic space

45

Housing of the valve assembly

50

multiplier valve

70

drilling

71

poetry

100

contraption

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2535237 A1 [0010]

Claims (7)

Contraption ( 100 ) for damping compressive forces, the device ( 100 ) comprises: - a cylinder ( 10 ), in particular circular cylinder, in which a hydraulic chamber ( 11 ) is trained; - one relative to the cylinder ( 10 ) telescopically along a central axis ( 1 ) displaceable hollow piston ( 20 ); - one at an end portion of the hollow piston ( 20 ) formed valve assembly ( 40 ) for dividing the hydraulic chamber ( 11 ) in a rear hydraulic chamber area ( 12 ) and a front hydraulic chamber area ( 13 ); - one in the hollow piston ( 20 ) along the center axis ( 1 ) movable separating piston ( 25 ), one within the hollow piston ( 20 ) formed gas space ( 21 ) from the front hydraulic chamber area ( 13 ), wherein the valve arrangement ( 40 ) one with the rear hydraulic chamber area ( 12 ) connected overflow area ( 41 ) and one over at least one channel ( 42 ) with the overflow area ( 41 ) connected eccentric hydraulic space ( 43 ), - a throttle mandrel ( 30 ), the front side of the cylinder ( 10 ) within the rear hydraulic chamber area ( 12 ) is arranged such that this in the overflow ( 41 ) is immersible, characterized in that the throttle mandrel ( 30 ) a peak ( 33 ), which corresponds to the overflow area ( 41 ) pointing side rejuvenated. Contraption ( 100 ) according to claim 1, characterized in that the throttle mandrel ( 30 ) on the overflow area ( 41 ) indicative side is designed cone-shaped. Contraption ( 100 ) according to claim 1 or 2, characterized in that the throttle mandrel ( 30 ) detachable with the cylinder ( 10 ) connected is. Contraption ( 100 ) according to claim 3, characterized in that the throttle mandrel ( 30 ) in a hole ( 71 ) of the cylinder ( 10 ) can be inserted and fixed there. Contraption ( 100 ) according to at least one of the preceding claims, characterized in that throttle mandrels ( 30 ) of different lengths L can be used. Use of the device ( 100 ) according to one of claims 1 to 5 as a regenerative energy absorbing element in a track-guided vehicle, in particular rail vehicle. Track guided vehicle, in particular rail vehicle, with a device ( 100 ) according to one of claims 1 to 5.

Images