DE2510255A1 - PNEUMATIC-HYDRAULIC BRAKE DEVICE - Google Patents

Description

my reference: 0453 Pt

WABCO Westinghouse Air Brake Company, Wilmerding, Pennsylvania, USA

Pneumatic-hydraulic braking device

The invention relates to a pneumatic-hydraulic brake device with a pressure fluid container, from which the hydraulic pressure medium via a control valve into the cylinder of a hydraulic pressure medium motor is controlled, whereby when the piston is moved in the In one direction, the hydraulic pressure medium acts on a brake application piston in order to initiate the braking process in this way. Each of these pistons is provided with a sealing member along which a limited amount of hydraulic pressure medium flows in the form of a leakage into a chamber on one side of the brake application piston, this pressure fluid is reintroduced from this chamber into the hydraulic pressure medium tank.

The German patent application P 24 53 966

shows a pneumatic-hydraulic braking device of this type, with a piston bearing seals, each of which while applying the brakes on one side with a hydraulic one Pressure medium is applied, the pressure being so great

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is that an undesirable amount of leakage losses of the hydraulic pressure medium flows past these seals from one side of these pistons and from there reaches the other side of the pistons. From there, the hydraulic fluid then flows outwards and in this way pollutes the environment.

The object of the invention is therefore to provide an automatically operating device with which the reintroduction or return of that hydraulic pressure medium ensured in the hydraulic-pneumatic braking device which flows past the seals of the pistons, these pistons on the one hand with a comparatively high Pressure of a hydraulic pressure medium can be applied.

According to the invention, a pneumatically monitored and hydraulically actuated braking device is provided, which one has hydraulic pressure medium container and two seals bearing piston, which on one side with a hydraulic Pressure medium of relatively high pressure are applied. There are also suitable lines or channels are provided through which the pressure medium losses flowing past from one side of the piston to the other side of the piston along the seals of the piston Pressurized and reintroduced into the pressure medium container, so that the pressure medium is not lost, but rather is retained for the pressure medium circuit.

The invention is illustrated in more detail below with reference to the drawing. In this show in purely schematic Way:

1 shows a vertical section through a hydro-pneumatic converter device known per se, via which the hydraulic brake application piston is acted upon with the hydraulic pressure medium will,

Fig. 2 is a vertical section through the pneumatic hydraulic system Braking device according to the Er

finding

Fig. 1 of the drawing shows a hydro-pneumatic converter device 1, via which the hydraulic pressure medium is controlled in a suitable hydraulic motor for actuating the brakes. This hydraulically operated motor is not shown in the drawing for the sake of clarity.

The structure and operation of the converter device 1 according to FIG. 1 corresponds to the hydraulic-pneumatic converter according to German patent application P 24 53 966. Therefore, a detailed description of this converter device 1 be waived.

The converter device 1 has a membrane 2, the inner circumference of this membrane between the part 3 and the Plate 4 is clamped. This plate 4 is connected to part 3 via screws 5, for the sake of clarity in FIG Fig. 1 of the drawing only two screws are shown.

The part 3 forms a physical unit with a shaft 6, the lower part of this shaft 6 in a bore 7 is slidably mounted. This bore 7 is provided in a housing part 8 which is part of the multi-part housing the converter device 1 forms.

As can be seen from Fig. 1 of the drawing, the interior of the bore 7 forms a chamber under the end of the shaft 7 9, which then with a hydraulic pressure medium from a hydraulic pressure medium container 10 via a valve member 11 is acted upon when this valve member 11 has detached from the valve seat 11 in a manner as in the above mentioned German patent application P 24 53 966 is set out in detail. To the flow of the hydraulic pressure medium to prevent from the chamber 9 in the chamber 13, during the movement of a hydraulic piston forming The plunger 6 and according to the pressure medium entry into the chamber 13 above the membrane 2 via the channel 15 is the Connect the guide tappet 6 with a suitable sealing member 16

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see.

Experience shows that even with the sealing members, however good they are, a limited amount of pressure fluid flows from the chamber 9 past the sealing member 16 into the chamber 13 whenever a braking process is initiated. Fig. 1 of the drawing shows that the hydraulic pressure medium - which starts from the chamber 9 along the sealing member

16 flows into the chamber 13 - from this EsiMier 13 via the opening 17 can flow to the outside of the uniform device. It is clear that this hydraulic pressure medium, which the opening

17 leaves, polluting the environment and therefore creating undesirable conditions. In addition, the hydraulic pressure medium is lost and may well be one for all. must be replaced by an equal amount of pressure medium which is taken from the hydraulic pressure medium container 10. The hydraulic pressure medium container 10 is therefore provided with a pair of observation glasses or observation windows 18 and 19 which are arranged one above the other in order in this way to inform the viewer when the pressure medium container is full or essentially empty.

FIG. 2 of the drawing shows a pneumatically controlled, hydraulically actuated forming device 20 according to FIG the invention.

As can be seen from Fig. 2 of the drawing, the converter device has 20 a housing made up of several parts. These housing parts are indicated with the reference numerals 21, 22 and 23 and are connected to one another by means not shown in any further detail in the drawing.

The housing part 21 has the shape of two opposite one another shell-shaped parts which are separated from one another by the wall 24. The upper, bowl-shaped limb of the Housing part 21 is closed by an upper cover 25, which is connected to housing part 21 by means of a multiplicity of screws 26 is releasably connected. In Fig. 2 of the drawing there are only two

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Screws 26 shown. This is how the bowl-shaped works Link of the housing part 21 together with the cover 25, so that a hydraulic pressure medium container 27 is formed. This Pressure medium container 27 can be filled with oil or with another suitable hydraulic pressure medium can be filled via the filling cap 28, which can be screwed into the cover 25.

As can be seen from FIG. 2 of the drawing, the outer circumference of a membrane is clamped between the housing parts 21 and 22. The inner circumference of this membrane 29, on the other hand, is clamped between the piston-shaped part 30 and a plate 31 which is connected to the piston-shaped part 30 via a plurality of screws 32. These screws 32 are passed through smooth bores in the plate 31 and screwed into a threaded part which is provided in the piston-shaped member 30.

The membrane 29 together with the piston-shaped part 30 and the plate 31 cooperate with the housing parts 21 and 22 in the Nielse that a pair of chambers 33 and 34 is formed on the corresponding opposite sides of the i'iembran 29. A pneumatic pressure medium can be introduced into the chamber 34 via a channel and the corresponding number of lines 35, the line 35 being connected, for example, to a brake cylinder opening of the usual brake control valve (not shown) of a compressed air brake device of a rail vehicle, and this brake control device is connected to the Engine driver is operated.

With the piston-shaped part 30, a hydraulic main piston 36 forms a physical unit, the lower end of which is mounted in a bore 37 which is provided in the housing part 22.

A spring 38 is mounted around the main piston 36, which lies between the piston-shaped part 30 and the housing part 22 and serves to the membrane 29 and the piston 36 in Direction of the brake release process in that shown in FIG

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La ^ e to move elastically. In this position the upper one hits End of the kolbeniö -migen part 30 against an annular stop 39, which is provided on the lower side of the wall 24.

As can be seen from Fig. 2 of the drawing, the piston 36 is provided with a bore 40 and two coaxial counterbores 41, provided, the counterbore 41 extending through the piston-shaped part 30 in the direction of the top thereof, while the counterbore 42 extends through the piston 36 towards its lower end. Between the lower end the bore 40 and the upper end of the counterbore 42, a tapered valve seat 43 of a sniffer valve 44 is formed, that at the top of a cylindrical member 45 is provided, which is slidably mounted in the counterbore 42.

In the wall of the counterbore 42, a groove is incorporated into which a locking ring 46 or snap ring is inserted is. Between this locking ring 46 and the cylindrical member 45, a spring 47 is mounted, which one of The O-ring 48 carried by the valve 44 presses against the valve seat 43, to be precise when the downward movement of the piston 36 begins the position shown in Fig. 2 of the drawing.

In the area of the lower end, the hydraulic piston 36 is provided with an annular groove running around the circumference, in which a sealing member 49 is arranged. The purpose of this sealing member 49 is to reduce the flow of the hydraulic pressure medium to prevent from the chamber 50 below the piston 3b in the chamber 34, through a small gap between the wall of the bore 37 and the circumferential surface of the piston 36, this gap is necessary in order to ensure a sliding movement between the piston 36 and the wall of the bore 37.

As can be seen from Fig. 2 of the drawing, a guide member 51 forms a physical unit with the wall 24 and is surrounded by the annular stop 39. The leading member 51 extends into the counterbore 41 of the hydraulic piston 36. In the immediate vicinity of the lower end of the same

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the guide member 51 with one extending along the circumference Provided annular groove in which a sealing member 52 is arranged is. The purpose of the sealing member is to prevent leakage of the pneumatic pressure medium from the chamber 34 to the lower part the counterbore 41 and via the bore 40 to prevent the valve 44 past into the chamber 50, which with. the hydraulic Pressure medium is filled. In addition, that prevents Sealing member leakage of the hydraulic pressure medium see from the lower Part of the counterbore 41 in the chamber 34.

Through the wall 24 and into the guide member 51 extends an underlying bore 53, v / g at the upper end of this lower bore 53 is surrounded by a shell-shaped filter 54, which is arranged in the hydraulic pressure medium container 27 and, for example, as a sieve is trained. The filter 54 is provided with an outwardly extending flange through which a pair of screws 55 are passed. These screws 55 engage in corresponding screw threads in the wall 24.

Starting from the lower end of the guide member 51, four arched bores 56 extend upward, which intersect the bore 53 (FIG. 3). The drawing clearly shows that the axes of these bores 56 are parallel to the axis of the bore 53. These bores 53 and 56 allow the hydraulic pressure medium to flow from the container 27 into the chamber 50. Subsequently, the valve 44 is released from the seat 53 through the lower end of the guide member 51 , which strikes against the shaft 57, which is connected to the valve 44 forms a physical unit. Subsequently, the valve 44 is brought into the release position when the hydraulic piston 36, the piston-shaped part 30 and the membrane 29 are pressed by the spring 38 into the position shown in FIG. 2 of the drawing, in accordance with the emptying of the chamber 34 via channel and line 35 and then when the conventional brake release valve returns to its brake release position.

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As can be seen from Fig. 2 of the drawing, the housing part 23 has a pair arranged parallel and at a distance from one another Lugs 58 and 5 "-> in which a socket is arranged is. In this way it is possible to use the converter device to be attached to a rail vehicle.

In addition, the housing part 23 has a bore 60, into the right end of which one end of a channel 61 opens, which extends through the housing part 23 and opens into the chamber 50 at the opposite end.

In the bore 60, a piston 62 is slidably mounted, on which a piston rod 63 is formed which extends through this bore 64. For this purpose is a provided at the bottom cover 65, the one with the left end of the housing part 23 is connected / bar via means not shown in any further detail in the drawing (FIG. 2).

At the left end, the piston rod 63 is provided with a bore 66 in which a bush 67 is mounted with a press fit, in this way the piston rod 63 via a linkage or joint, not shown, for example with a disc brake or another device which can be operated by the transducer device 20.

In the piston 62 and in the piston rod 63 there is a tapering recess 68 and a coaxial recess 68, likewise one tapered counterbore 69 is provided. The purpose of the conical design of the recess 68 and the counterbore 69 is it is to remove those air bubbles trapped in the hydraulic fluid flowing from the chamber 50 starting in these two parts 68 and 69 and flows into the chamber, which flows through the piston 62, the housing part 23 and the Channel 61 is formed.

In order to ensure the possibility of emptying the container 27 and the chambers 50 and 70 in the event of repair work, e.g. B. Replacement of the worn parts to open up is the housing part

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23 with a bore 71 and a threaded bore located coaxially thereto 72 for receiving a releasable threaded plug 73.

As FIG. 2 of the drawing shows, the circumference of the piston 62 is provided with an annular groove in which a sealing member 74 is mounted in order to prevent the flow of the hydraulic pressure medium to prevent from the chamber 70 in that part of the bore 60 which is on the left side of this piston 62 lies.

As already indicated above, even when using the very best sealing members 49 and 74 in practice not be prevented that limited amounts of pressure fluid flow past these sealing members 49, 74, namely when these sealing members are exposed to a comparatively high pressure. Accordingly, that in Fig. 2 is the The converter device 20 shown in the drawing is provided with means with which the sealing members 49, 74 as Hydraulic pressure medium flowing past leaks is fed back into the container 27 so that this pressure medium is not lost rather, it is retained in full for the work process.

As can be seen from Fig. 2 of the drawing, is arranged by the housing parts 22 and 23 substantially vertically Channel 75 passed through. This channel 75 opens at its upper end into the chamber 83, but at its lower end into the wall of the bore 60, which is in the immediate vicinity of the left end of this wall. In this way the Channel 75 is a line via which the hydraulic leakage losses flow past the sealing member 49 into the chamber 33 can. From there, the pressure medium leakage losses can enter that part of the bore 60 that is to the left of the piston 62 is located.

As shown in FIG. 2 of the drawing, the opening is on

the wall of the bore 60 in the immediate vicinity of the left

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At the end and diametrically opposite the opening of the channel 75 on the wall of the bore 60, one end of the channel '/ 6, which extends through the housing parts 23, 22 and 21 and the upper cover 25, the opposite end in a surface 77 opens, which lies on the lower side of this cover 25. The area 77 lies slightly above the area of the hydraulic pressure medium in the container 27.

It has been found that the maximum cross-section of the channel 76 should not exceed the V / ert 8 mm, because that hydraulic pressure medium with the aid of the pneumatic pressure from that part of the bore 60 via the channel 76 back into the hydraulic pressure medium container 27 moves v / er dt η is, the to the left of the piston 62. When the cross section of the channel

76 would be greater than 3 mm, the pneumatic pressure would come into effect as a result of the surface tension of the hydraulic pressure on the hydraulic pressure medium with the result that this hydraulic pressure medium is not returned to the container 27 in the desired manner; would be.

The operation of the device according to the invention is the following:

When braking is initiated in a known manner is to be, the hydraulic pressure medium flows out of the chamber 50 via the channel 61 into the chamber 70, in accordance with the requirements the control of the pneumatic pressure medium in the chamber 34. In this way, the membrane 29 is bulged and. a downward movement of the piston-shaped part 30 and. of the piston 36 causes.

However, a small amount of hydraulic pressure fluid flows out of the chamber 50 on the sealing member. 4y of piston 33 past into the chamber 33; the hydraulic pressure medium also flows out of the chamber 70 on the sealing member 74 of the piston 62 past into that part of the bore 60 which is on the left side of the piston 62.

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The aforementioned bulging or deflection of the I'iembran 29 and the downward movement of the piston-shaped part are effective in such a way that the volume of the chamber 33 is reduced will. This chamber does not have any vent to the atmosphere. The consequence of this is that with decreasing volume the Chamber 33 the pressure in this chamber increases. After a small amount of hydraulic fluid has accumulated in chamber 33 as a result of the flow of pressure medium from the chamber 50 to the seals 49 of the hydraulic piston 36, increase the subsequent deflection of the membrane 29 and the downward movement of the piston-shaped part 30, the pressure in the chamber 33 with the result that this pressure increase in the Chamber promotes the hydraulic pressure medium in this chamber and in the channel 75, from where it is in the part of the bore 60 on left end of the piston 62 flows. There the pressure medium mixes with that hydraulic pressure medium which is from the Chamber 70 is pressed past the sealing member 74 of the piston 62 into this part of the bore 60.

As FIG. 2 of the drawing shows, the wall of the bore 64 in the lower cover 65 is spaced apart by a pair provided annular grooves lying opposite one another, in \ tfelchen the sealing members 78 and 79 are mounted, which form the circumferential surface of the piston rod 63 surrounded by a seal. So when the piston 62 by Control of the hydraulic pressure medium into the chamber 70 moves to the left, so that the volume of this part of the bore 60 on the left side of the piston 62 becomes smaller, the pressure in this volume or space increases.

When the pressure in this part of the bore 60 on the left side of the piston 62 in accordance with the movement of this piston increases to the left, this pressure increase causes the accumulated hydraulic pressure medium to move in the bore 60 on the left side of the piston 62 into the channel 76 and thus through this channel 76, the cross section of which is smaller

ρ
than 8 mm. Then it is:

medium in liquid container 27.

than 8 mm. Then the hydraulic pressure

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From the above considerations it can be seen that the hydraulic pressure medium, which is located on the sealing member 49 of the piston 36 moves past and the hydraulic pressure medium, which sweeps past the sealing member 74 of the piston 62 as a leak, into the hydraulic pressure medium container 27 again i will be.

- patent claims -

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Claims (11)

PATENT CLAIM F. 1.iPneumatic-hydraulic! See braking device with a variety of housing parts, of which certain housing parts are provided with bores, characterized in that that stops arranged in parallel one behind the other are provided, of which one stop is in one of these Boreholes according to the pneumatic pressure introduced or vented in one of the two chambers in opposite directions Directions on opposite sides of the other stop through cooperation of that other stop and a pair of the housing parts is movable, that a hydraulic container is provided, of which a hydraulic Pressure medium into which one of the bores can be controlled that a third stop is arranged, which is in another Drilling these holes in accordance with the build-up of hydraulic pressure in one of the two chambers on the opposite one Pages of the same is movable in that one of these stops is in one direction of this bore moved that sealing means are arranged on each stop in order to change the hydraulic pressure medium from one bore to the other bore of these two chambers and from one of these two chambers to the other chamber on the other side of this stop to prevent a first line is provided which this first chamber connects with the second chamber that a second line is arranged, which the second chamber with the hydraulic Pressure medium tank connects and that the first and the second line work together so that the return of the hydraulic pressure medium flowing past each seal into the hydraulic pressure medium container will. 2. Braking device according to claim 1, characterized in that that the movement of the other stop of this pair of stops arranged one behind the other in one direction according to the control of the pneumatic - A 2 50988Α / 075Λ matic pressure medium in one of these two chambers so effective becomes that the volume of the other of these two chambers is reduced, and that also these openings in this chamber the pressure increases so that the hydraulic pressure medium from this chamber via the first line, the second other Chamber and the second line in the hydraulic pressure medium tank flows. 3. Braking device according to claim 1, characterized that the movement of the other stop of these two consecutive stops in the one direction according to the control of the pneumatic Pressure medium in one of these first two chambers is so effective that the volume of the other of these first two Chambers is reduced in size in such a way that the pressure in this chamber rises and thereby the flow of the hydraulic Pressure medium from this chamber into the z ·. Another chamber is effected via the first line, and that the third stop in one direction according to the control of the hydraulic pressure medium in one of these second two chambers is so effective that the volume of the other This second two chambers is reduced in size so that the pressure in this chamber increases and the flow of the hydraulic pressure medium from this chamber into the hydraulic Pressure medium tank is effected via the second line. 4. Braking device according to claim 1, characterized in that the housing part with the other bore Contains drainage means via which the hydraulic pressure medium can be discharged from one of these second two chambers is. 5. Braking device according to claim 1, characterized in that in the housing part with the other Bore a line is provided, which one and these other, the hydraulic pressure medium leading bores with the third stop during the movement of this one pair of the stops arranged one behind the other in the one direction - A 3 509 8 84/0754 connects, 6. Braking device according to claim 1, characterized that the first line extends through those parts of the housing in which the one and the other bore are provided. ■ ?. Braking device according to Claim 1, characterized in that the second line extends through extends through all housing parts. c. Braking device according to claim 1, characterized that the hydraulic pressure medium tank is arranged in one of these numerous housing parts according to claim 1, characterized in that g e characterizing η e t, that the maximum cross-section of this second line is 3 mm "". 6 'S - T-, braking device according to claim -S _5, characterized in that arranged sealing means are provided on one of these the one and the other bore having housing parts, which surround the first line and are mounted between the housing parts so that a leakage flow of the hydraulic pressure medium from this first line out prevents v / ird. 11. Braking device according to claim 7, characterized _s that sealing means are provided which are adjacent on each of the two pairs of housing members of the plurality of housing parts are arranged, and that each sealing means surrounds the second line and is supported between the corresponding pair of the housing parts in such a way that a leakage flow of the hydraulic pressure medium out of the second line is prevented. S0988W075A