DE8327019U1 - Hydraulic device - Google Patents

Description

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Description

Hydraulic device
5

The invention relates to a hydraulic device as specified in the preamble of claim 1 Kind ». j

Then occurs in such hydraulic devices disturbing noise development when the pressure medium from a high working pressure and possibly at large flow rate is quickly released to the pressure prevailing in the process, which can be practically zero * This noise development is probably due to a cavitation effect in sections of the flow path, in which the pressure medium is strongly accelerated and relaxed at the same time. The noise makes The lower the counter pressure in the area behind the relaxation area, the more noticeable it is Section of the flow path is. The working, control or regulating elements in the hydraulic device are provided, for example slide control valves in a single or series arrangement, hydraulic motors, Working cylinders, safety valves, flow control valves and similar hydraulic components are included which results in a switching position under the working pressure in which the pressure suddenly increases to the discharge pressure is to be dismantled. With spool control valves with

unpressurized passage, for example, the piston valve has a through hole which is blocked in the control positions of the piston valve and in the neutral middle position to the pressure medium in

unpressurized flow allows the outflow. At 35

Switching from a control position to the neutral position the work pressure that has to be met up to that point must

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be abruptly dismantled. In this case, this takes place via two blinding-like opening passages from the housing into the channel of the piston valve ^ and from the channel of the piston valve in turn into the

Housing and to the reservoir. The in one becomes similar Safety valve Pressure present when the * set pressure limit is exceeded suddenly above the .. valve element of the safety valve dismantled. In

In both cases, the pressure release is practical

without a back pressure instead, so that at higher

; Flow rates over 30 liters / min. a clear and

ί there is a loud noise. One way to Ge

Noise damping forms a counter pressure that counteracts the relaxation of the pressure medium. However, this means could not be used for the aforementioned hydraulic device because after the pressure reduction it is absolutely necessary that the pressure medium with the lowest possible flow resistance

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flows off "

It has already been proposed (German patent application P 33 08 575), the generation of noise

for spool control valves with an unpressurized through-26

to reduce gear by the fact that the two throttle points, which depend on its movement in the slide of this valve, are designed differently, so that a higher pressure gradient occurs in the first throttle body than in the second throttle point. This has the effect that a greater proportion of the high pressure upstream of the first throttle point is reduced in the first throttle point than in the second throttle point. The counter pressure then counteracting the pressure medium upstream of the second _oc throttle point damps the noise development behind the first throttle point, while the flow noise in the second throttle point thanks to the only slight pressure difference there

or relaxation noise of the pressure medium is quiet, although the pressure medium is practically without

can relax a counter pressure. Apart from that, 5

that thereby the construction of the slide control valve is more complicated, it requires a care- ^l fältigen vote of the chosen constructive |) "tion to the working pressure range uni the flow (N Nevertheless the achievable noise reduction is still unsatisfactory, as the two throttle ^in.! strictly dependent on the movement of the piston follower and therefore work largely independent of pressure and flow rate.

The invention is based on the object of a

To create hydraulic device of the type mentioned, in which despite an unimpeded outflow of the relaxed pressure medium, the pressure reduction is largely noiseless.

According to the invention, the set object is achieved by the in the characterizing part of Perfrexktluispruchs 1 specified features solved.

With this design, the throttle device actually only comes into effect when a high pressure is to be reduced, specifically in strict dependence on the pressure to be reduced. It ^does: no matter how the adjusting movement of the limb or via which Hub it takes place, but the throttle

The device builds up a counterpressure for the pressure to be released, which is precisely used to dampen the noise is needed. As soon as the pressure has been reduced to the level of the pressure behind the throttle device is, takes the working element of the throttle device its ready position again, in which it does not hinder the outflow of the pressure medium. The throttle device can be used practically for the most varied types of links, since it is only based on the work pressure that needs to be relieved. A constructive vote of the links the hydraulic device on the throttle device is not required. The one between the shock wave and the pressure reducing the drain from the member must do so against the back pressure of the throttle device do, whereby the noise is suppressed. The further pressure reduction via the throttle device can be easily adjusted so that no noticeable noise is generated here either occurs more. The pressure difference that is reduced via the throttle device depends on the amount of pressure to be relieved in front of the limb. It's ok but the amount can also be adjusted without further ado, which allows the throttle device to flow off after the pressure has been reduced.

An expedient embodiment of the invention is based on claim ? emerged. If such a throttle device is not sufficient for noiseless relaxation of the pressure medium, e.g. because the delivery rate or the working pressure are too high, at least one further throttle device is arranged behind the throttle device, which ensures a further pressure reduction stage up to the final discharge pressure and in turn a counter pressure the pressure medium emerging from the first throttle device

builds up. Each additional throttle device is included The help of the pressure in front of the throttle device in front of it is so biased that again to a strict pressure dependency is achieved, which for a noise attenuation independent of the actual present pressure. Since the further throttle device is then in its ready position goes when the pressure reduction is completed, then the outflow of the pressure medium is no significant flow resistance more opposite.

It is conceivable that each throttle device biasing pressure is also derived centrally only from the pressure to be relieved via the limb and thereby is regulated so that it provides a different back pressure value in each throttle device.

Another useful embodiment of the invention is apparent from claim 3. The staff for the work element is in this training in Controlled as a function of the pressure to be relieved, so that at a higher pressure to be relieved also the actuating force with which the working element generates the noise-dampening counter pressure increases.

Another structurally simple and effective embodiment of the invention is based claim ¹ I

³ ^ emerge. In the case of this differential piston, a relatively small area of application is sufficient to generate an actuating force which changes as a function of the pressure to be reduced and which in turn is responsible for the counter pressure for noise dampening. The other side of the differential piston throttles the pressure medium flowing in the drain to such an extent that the predetermined back pressure for the noise

damping is built up and that this counter pressure

f is strictly dependent on the pressure to be reduced

<! with this changes.

g: ° Alternatively, there is also an embodiment

favorable, as explained in claim 5. Here, too, the pressure to be relieved is tapped and

* from it the actuating force for the working element of the

• Throttle device generated, but not directly on * ^ hydraulic way, but mechanically or electromagnetically. This could, for example, be purposeful if, for structural reasons, there is no hydraulic connection between the pressure connection to the link and the downstream throttle device

is possible.

The feature of claim 6 is also important, since this weak spring ensures that the working element

remains in the ready position when the

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Hydraulic device is put into operation.

<Another, expedient embodiment goes out

Claim 7 emerges. This training takes place

the build-up of the back pressure depending on the

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Flow rate, which is determined by the size of the flow

, aisle cross-section can be determined.

As an alternative to this, an embodiment such as emerges from claim 8 is also expedient. At this 30th

Training becomes dependent on the pressure to be relieved

Back pressure is regulated independently of the flow rate, as it also depends on the preload that is applied to the

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Valve element is applied by the spring.

_t The feature of claim 9 is also appropriate «ο

because inexpedient swinging movements of the Valve element are suppressed.

Another important consideration is also in Claim TO included. This difference in area ensures that after the Pressure on the pressure level prevailing in the process due to the flow dynamics on this larger area of the differential piston attacking force pulse quickly moves the differential piston into the ready position transferred, in which he has to stand when the pressure reduction has been carried out in a noise-damped manner.

Particularly effective noise attenuation, even with high working pressure and large delivery rates, can be achieved with the regularity according to claim 11.

Claim 12 emphasizes the hydraulic members for which throttle devices which can be prestressed in this way are preferably useful.

Execution mandrels are described below with the aid of the drawings the invention explained.

Show it

1 schematically shows a first embodiment of a hydraulic device,

Fig. 2 schematically shows a second embodiment

a hydraulic device,

til t · f # · · · *

t ■

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3 schematically shows a third embodiment of a hydraulic device,

4 schematically shows a fourth embodiment

a hydraulic device,

FIG. 5 shows a detail, partly in section, from the previous embodiments of FIG Hydraulic devices, and

6 shows a detail variant, in section.

In a hydraulic device 1 according to FIG a working, control or regulating element 2 from a pump 3 with pressure medium from a reservoir R via a pressure line 4 is applied. Link 2 can

a spool control valve with a spool valve,

a safety valve, a flow control valve or the like. There can also be several battery-type be combined slide control valves, safety valves or the like, which are connected to a 25th

common drainage line 5 are connected, which are connected to a reservoir R via branch lines 5a, 5b, 5c, and 5d, specifically via throttle devices 6,6 ^f , 6 ^f ', 6 * ^f · arranged therein in series. In

ολ of ^the discharge line 5 is opposite the pressure line 3U

4 a significantly lower pressure or no pressure at all when the link 2 is working properly in such a way that it interrupts the connection between lines 4 and 4 and therefore the application of pressure

_ef _ from line 4, e.g. to other consumers whether '

or the pressure in the pressure line 4 is monitored as a safety valve.

• · · · Il I * ♦ ""

ι II III | _a ,,

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In the link 2 or in front of the link 2, a control line 7 branches off from the pressure line 4, which is connected to the

_ Drain line 5 into the opposite side ο

first throttle device 6 opens. A further control line 8 branches off from the drain line 5 upstream of the first throttle device 6 and is connected to the second throttle device 6 * on the side of the second throttle device 6 * facing away from the drain line section 5. A further control line 9 branches off from the discharge line section 5a before the second throttle device 6 », which is connected ^{to the third throttle device jg 6 lr on the side facing away from the discharge line section 5b.} From the drain line section 5b, a further control line 10 branches off before the third throttle device 6, which is connected to the fourth throttle device 6 ″ 'on the side facing away from the drain line section 5c.

In the control lines 7 »8, 9 and 10 there can be throttles 14,15,16 and 17, expedient catfish adjustable throttles, be arranged.

Embodiments of the first throttle device 6 can be seen in detail from FIGS. 5 and 6. the further throttle devices δ ', β ^, β "· correspond, in their structure of the throttle device 6, so that it is unnecessary to explain them in detail.

According to FIG. 5, the member 2 has a cuboid housing 24 with a pressure line connection 25 and a drain line connection 27 between which (not shown) the active elements of the member are arranged, e.g. a piston valve, a valve element with control, a proportional magnet with

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I * Il * I it

a metering device, and the like.

In the area of the mouth of the drain line connector 27, a seat 42 is formed on the housing 24, 2.B * by special processing. A further housing 28 is attached to the throttle device 6 on this side of the housing 24. The housing 28 is

_Lö holds a chamber 29 'and a pilot chamber 30. The pilot chamber 30 is in flow connection via the control line 7 with the pressure line connection 25. The throttle 14 is shown as a grub screw with which the passage duroh the control

jg line 7 is changeable.

In the chamber 29, a working element 31 of the throttle device 6 is arranged as a differential piston is trained. One side, which is larger in the area of application, is designed as a throttle body 32 forms, while the other side 33 is arranged on a piston 38, the pilot chamber 30 of separates the chamber 29 and delimits the pilot chamber 30 with the side 33.

A recess 34 is provided on the throttle body 32 on the side facing the drain line connection 27, from the radially outwardly extending notches form recesses 35, the purpose of which will be explained later will. A weak spring 37 is supported on a shoulder 36 of the working element 31, and the other one End, for example, against the housing 24. The spring exerts a weak force on the working element 31, through which the working element 31 remains in the position shown, the standby position of the Working element 31 is in which this is a substantially unthrottled flow connection between the

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Drain line connection 27 and a drain connection 43 in the housing 28 releases. According to FIG. 5, the drain line section 5d, which leads directly to the reservoir R, is connected to the drain connection 43. This is the case with a hydraulic device in which only the throttle device 6 is provided. | i According to FIG. 1, however, at the outlet connection 43 k]

and the discharge line section 5a the second '

Throttle device 6 'arranged. The pilot pressure for the second throttle device 6 ^f , which is not shown in FIG.
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The hydraulic device according to Figures 1 and 5 (with only one throttle device 6) works as follows:

When the member is in positions in which the flow connection between the pressure line connection 25 and the drain line connection 27 is interrupted, there is a high pressure in the pressure line connection 25. This pressure is also in

_οκ the pilot chamber 30 are present, where it is on the side Zo

33 moves the working element out of the standby position shown in full lines until the throttle body 32 rests on the seat 42. Any leakage oil can still flow essentially unhindered to the drain line = »- ^: section 5d, since the recesses 35 keep a constantly open connection free. There is no significant pressure in the discharge line connection 27, but the pressure of the reservoir R.

If now the member 2 is brought into a position in which it the flow connection between the pressure ' line connection 25 and the drain line connection 27

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produces, the pressure P must be reduced to the pressure of the reservoir, that is, the pressure medium relaxes. The pressure P from the pressure line connection 25 then also acts in the drain line connection 27 and tries to force the working element 31 into the drawn ready shaft position in order to create an outflow to the reservoir that is as unthrottled as possible. De ^>, however, counteracts an actuating force S, which is generated via the pressure in the pilot control chamber 30 on the side 33 of the working element. The higher the pressure P in the discharge line connection 27, the greater the actuating force, so that a deliberate throttling effect is generated, due to which a counter pressure P _s that is opposite to the pressure P builds up

is directed. The pressure medium can therefore not relax freely from the pressure line connection 25 into the discharge line connection 27, but there is the counterpressure that causes noise attenuation. The throttle body 32 works together with the seat UZ and forms a throttle point via which a predetermined pressure difference is reduced so that the pressure medium has to relax over a further stage. Since the pressure reduction in this case is over

If several (at least 2) stages are carried out, a noise will be generated prevented by the fact that the first relaxation between the Druckleitungaanschluss 25 and the drain line connection 27 takes place against the counter pressure, while the second relaxation between the drain line connection 27 and the drain connection 43 only via a small pressure difference takes place in which no noise (due to cavitation) occurs anyway.

It is important that the counter pressure P _g to the pressure P always depends on the size of P

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is built and consequently when the pressure P decreases, the counterpressure P "also decreases. Through the recesses 35 of the throttle body 32, a quantity-regulated outflow takes place of the pressure medium in dependence on the ratio of the pressures P and Pg, whereby, directed around pressure P _g according to the size of the page 33 of the Differeatialkolbens, which forms the working element 31st

Should the pressure difference over which the pressure medium between the drain line connection 27 and the drain port 43 relaxed, still so big

be that also here a noise development su Ib

is feared, then it is expedient to ^{connect at least one further throttle device 6 f} here, which in turn generates a counterpressure in the chamber 29 of the first Drostseleinriehtung 6, with which the relaxation noise is muffled. The pressure medium is then only finally released in the second throttle device 6 'or, if the pressure is still too high, only in the last of all the throttle devices provided.

If now the pressure reduction has progressed so far that in the pressure line connection 25 approximately the The same pressure prevails as in the chamber 29 or in the outlet connection 43, then the actuating force S is like this small that the flow dynamics from the drain line connection 27 is sufficient, the working element 31 to move back into the drawn ready position, in which no throttling for the running pressure medium flow takes place more. This is particularly important, e.g. for spool control valves in the position for pressureless flow, since the pump 3 uses the pressure medium with as little as possible

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Flow resistance through the entire hydraulic flow should pump into the reservoir so that 5

wasted energy unnecessarily and not the pressure medium

is heated.

In the embodiment of the first throttle device 6 according to FIG. 6, the control of the pressure medium flow between the discharge line connection 27 and the discharge connection 43 takes place in a pressure-dependent manner, and not quantity-regulated, as in the embodiment according to FIG 'Has a deep, pot-shaped recess 39 in the throttle body 32', in which a valve element 41 loaded by a strong spring 40 can be displaced. The valve element 41 is designed here as a ball which can be pushed ^{out of} the recess 39 by the spring 40 so far that it closes the drain line connection 27 with its outline as soon as the working element 31 is connected to the throttle body 32 'on the seat 42 by the actuating force S is applied. The pressure in the drain line connection 27 must then first press the valve element 41 back into the recess 39 before the pressure medium can flow out via the recesses 35 '. Until the pressure in the drain line connection 27 has pushed the valve 41 completely back into the recess 39, the relaxation takes place as a function of the force of the spring 40; only then does the pressure medium flow through the recesses 35 »in a quantity-controlled manner.

As soon as the pressure at the pressure line connection 25 has reduced so far that it corresponds to the pressure in the drainage

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schlufö 43 corresponds approximately, is through the dynamic force of the flow the working element 31 moved into the drawn standby position, eo that the pressure medium then flow off without throttling can.

The throttle device 6 can also be combined with further Combine throttling devices that are either the same or according to Pig. 5 can be constructed.

FIG. 2 shows another embodiment of a hydraulic device 1 ', in which the control of the individual working elements "? He throttle devices 6, 6", 6 ", 6"' takes place in a different manner than according to FIG 7, the control line 8 branches off directly, then the control line 9 ¹ from the control line 8 * and from this

finally the control line 10 *. In the tax 20

lines 8 ^f , 9 ^r and 10 are throttles 11, 12 and 13,

preferably adjustable, arranged. Furthermore can (not shown) simple valve devices are incorporated into the control lines so that the __ Pre-control pressures for the working elements of the others Throttle devices in the manner explained with reference to FIGS. 1 and 5 depending on the pressure to be reduced are adjustable.

" _O In the embodiment of FIG. 1, link 2 is no

IV only throttle device 6 downstream. It would be but also conceivable that several such throttle units' directions are connected in series. The throttle

IV ' device 6 has a mechanical Stellan drove 18, who had a transmission connection a pressure sensor 19 is connected. It would be conceivable that a lever connection from the pressure sensor

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Via the transmission 20, one in each case from the pressure in the pressure line 4 dependent actuating force is transmitted to the mechanical actuator, which then according to the pressure in the pressure line 4 moves the working element in the aforementioned manner.

According to Fig. 4, in turn, only a single throttle device 6 ^V downstream of the member 2, in this hydraulic ^{device 1 IM} in the pressure line 4, a pressure transducer 21 is arranged, which converts the pressure in the pressure line 4 into an electrical signal, and via a line 22 to an actuating magnet 23, preferably a proportional magnet, which is structurally connected to the throttle device 6. In this way, an electrical signal that is dependent on the pressure in the pressure line 4 is used to set the actuating force for the working

element of the throttle device 6 ^V to change sad to move the working element as explained with reference to FIGS.

It is obvious that the throttle device 6 ^{V can} also be followed by further throttle devices if the pressure to be reduced is so high overall or the flow rate is so large that the noise development could never be satisfactorily suppressed via the reduction stage formed by the throttle device 6 .

Claims (2)

25 1. Hydraulic device, with at least one adjustable working, control or regulating member, which consists of a
Pressure source can be pressurized and is connected to at least one drain and in at least one position establishes a connection from the pressure source to the drain, 30 over which the pending pressure in front of the link up to the
Pressure in the drain can be reduced, characterized in that in the direction of flow of
the pressure source (3) to the outlet (R) is followed by a throttle device (6,6 ·, 6 ", 6 '") that can be tensioned before the member (2) 35, which is a working element exposed to the flow to the drain (R) (31,31 ') contains that from a stand-by position that does not influence the flow -2- is adjustable from the pressure in front of the member in working positions that the working element with the before Member pending pressure (P) or a pressure derived therefrom is applied and a predetermined one in the process Passage cross-section limited, and that the working element (31,31 ·) in the direction of its readiness position through one of the difference between the anstejQ in front of the limb existing pressure and the pressure behind the throttle device dependent force is loaded. _ir . 2. HydrauXikvorrichtung according to claim t, characterized g ek en rr. shows that behind the throttle device (6) at least one further pretensionable U-throttle device (6 ', 6 ^ft , 6 ^f ") is arranged, the working element (31,31') of which · as a function 2Q of the pressure to be reduced in front of the preceding throttle device (6,6 ', 6 ^tf ) can be adjusted from its readiness division. 3. Hydraulic device according to claims 1 and 2, characterized in that the throttle device (6,6 ', 6 ^1f , 6 "') has a chamber (29 ), in which a seat (12) is provided in the area of the confluence of the discharge line, and that in the chamber (29) the working element is dependent on a function of the pressure to be reduced in front of the member (2) or in the case of several throttle devices from the pressure to be reduced in front of the working element of the respective preceding throttle device (6,6 ', β ··) variable actuating force (S) Jala zur AnI ^ on the seat (42) can be acted upon . -3- 4. Hydraulic device according to claims 1 to 3, characterized in that the worker element (31 «31 ') is a double acting differential 1 O i, is tialkolben, one side of which as with the seat I (42) cooperating throttle body (32,32 *) and f its other and opposite side . (33) the eleventh pilot chamber (30) delimits »the one with \ one from the Druok (P) in front of the limb (2) or at v several throttle devices (6.6 · 6 · *, 6 ^η ·) from the I. Pressure "in front of the working element (31» 31 ') d6t in each case | previous throttle device (6,6', 6 ··) ab « t Ιβΐϋβίϊο» pilot pressure is applied. IB ί 5. Hydraulic device according to claims 1 and 2, '■ characterized in that the Ar belts-; element with a mechanical or electromagnetic seriesi Actuating device (18,23) is in working connection, | with which the actuating force (S) for the working element | depending on the pressure to be reduced erzeij & ar is. % 6 ~ hydraulic device according to speeches 1 to 4, characterized in that the Arbelts- element (3T, 3t *) by a weak spring <37) is burdened towards its readiness position. 7. Hydraulic device according to at least one of claims 1 to 6, characterized in that the seat (42) adjacent working element
(31.3T) the predetermined passage area- (35.35 »)
limited. 8. Hydraulic device according to at least one of the • fl · · I · I · I • t ■ -4- Proverbs 1 to 7, characterized in that that in the throttle body (32 ·) of the working element (31 ·) a valve element (41) against the force of a preferably adjustable spring (40) arranged in the working element is movably guided, which is at the end3st can be pressed against the seat (42) in the end position of the working element. 9. HydraulikvoFriehtung naoh claim 8, characterized in that that in the working element (3 1 *) a damping device (44) for the valve element (41) is arranged. 10. Hydraulic device according to at least one of claims 1 to 9, characterized in that that the pilot chamber (30) delimiting side (33) of the differential piston is considerably smaller is than that exposed to the flow in the chamber (29) Impingement surface of the throttle body (32). 11. Hydraulic device according to at least one of claims 1 to 10, characterized in that that the actuating forces for the working elements of the throttle devices to each other in one by the square root of the particular to be mined Pressure is in the right proportion. 12. Hydraulic device according to the preceding claims, characterized in that the throttle device (s) (6,6 ', 6' ·, 6 "') one or several slide control valves with pressureless Flow, a safety valve or a volume 35 downstream control valve is (are).