DE1908156C3 - Self-pumping hydropneumatic suspension strut with internal level control for vehicles, in particular motor vehicles - Google Patents

Description

renz of the gas cushion (14) in the gas spring space (13 The invention is based on the known strut or 213) between a predetermined upper. according to Fig. I on p. 8 of the magazine "Motor vehicle and a given lower limit load technology". Booklet IM 968, from. Deviating from that of the strut, so that when the above generic term of the invention is exceeded, a further regulation 45 of this known spring, referred to as a proposal, is not effective (15, 215 or 515) by sucking the oil from the oil reservoir derbein the working piston. and subsequently provided bc damping devices. A very familiar delivery of gas through the pump - weak damping is only achieved with a rclastange (19, 219, 419 or 519) and with a sub-wide annular gap between the piston and cylinder exceeding the lower limit load, a further 50 wall. In this known strut, the descent is prevented by a pressure equalization between the working chamber (12 or 212) and the oil reservoir, which is arranged in a pressure cylinder, and an oil-filled, with the oil reservoir in of- (15, 215 or 515) , whereby a connection bypassing the annular space , the outlet (opening 362 and / or outlet valve The construction shown, 360) of the pump chamber (24 or 324) in itself 55 that this annulus is not used as an oil storage chamber, but is located at the highest point in a well-known manner Piston rod exit from the net. Catch oil passing through the pressure cylinder and

2. Suspension strut according to claim 1, characterized in that the oil reservoir / uriickzufleiten so as to relieve the pressure in a manner known per se in the rod seal at the outlet from the entire axially to the working chamber (12 or 212), means at Übcrschreißenden gas spring chamber (13 or 213) in the region of the target levels tung oil from the working space in the said surface between oil and gas, a separation can be oil reservoir flow, are not specified body (17 or 217) loading of solid material or recognizable in the picture. The user of the movably arranged, who is left with a capillary suggestion, forms these means through forces with oil-filled annular cylindrical gap with 65 creation of controlled or uncontrolled Verder inner wall of the gas spring space (13 or connecting devices between the working space 213) and by means of support ( Collar 18 or and the oil reservoir or between the Arbcits- 241) is secured against sinking into the oil chamber. to look for or to provide for space and the annulus

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hen. The means specified in the proposal are not harmful to the room since the gas is exceeded when it is exceeded

^ttn, ° "S5S ^v finer free OherfiHnh,» ™ i ι., _Λ, is reclaimed. Furthermore, there is the advantage η ⁱⁿ £ \ fmölvoSs? aurSwi.Sl ^ rf T * ^{that the} erft dung contemporary strut with a pre-Oas mwoW >"iSteSSH ™ ISS ' ^mGa ! i ^ed f ^r - 5 given lower and a given upper space, the known pressure-dependent gas release limit load can be designed
In a KS Γ demsche interpretation document visible 7ΕΪ ^ "ί ^. ^^« "« nnten 1 287454 burned FWterw! * 5 only de? ÖNor-Zeißchnft known colorants of the work room un- advisory room and the pump rod according to the type described at the beginning &] ^ ^Ό ™ * ^^^ ^Λ Φ ™ * ^η «™ * ™> » designed and arranged that in the> on the work room In the oil reservoir, the working space and the high-tension gas cushion space draining oil e.ne large amount of gas are dissolved, however, by a sealed separating piston, of which a part in the oil reservoir is degassed. The oil storage space is not designed for high pressures, but in the one from the oil storage space in the Ar- and is closed with a cap made of a small amount of gas _/ rubber produced by an oil required from the working space and this oil is loosened in the working space of the gas cushion Leak oil collecting chamber in connection. A pressure out gas is withdrawn by solution. This interplay, which is repeated between the working area and the oil storage area, must not be minimized, since it would destroy the closure device and the amount of gas in the gas cushion and cap for a short time. The pressure equalization increases the amount of oil in the oil reservoir, where a "" prevents the opening of a de-energizing pressure from building up, which adversely affects the intended pressure relief of the nals inside the pumps! Delay piston 'is tapped. At risch makes. That is why it is also stated in the specified literature - application of a free surface between oil and turquoise - that this known solution would be like that which was discarded if the separating piston were omitted. _a5 strut will not be operational for a long time, as a result

The invention is based on the object of a spring; Gas dissolution and outgassing properties of

trainee of the genus mentioned at the beginning! in a short time gas from the gas cushion into the oil

Rien that the use of free surfaces alternate between the storage room and such a high one there

see oil and gas not with the indicated pressure that the cap would build up

Has disadvantages, so that a simple construction 30 pushed away. Gas blown off and the shock absorber un-

Functionally reliable structure with small dimensions would be unusable. The shock absorber has no means

gen can be realized, and furthermore so. that this is necessary for a defined termination of the pumping when

Strut a defined lower and a defined range of a predetermined limit load and

has upper limit load. One has the disadvantage of a large oil reservoir

Pressure relief of the piston rod seal and 35 space. This must contain so much oil reserve that

a leakage oil return can be dispensed with. Except- it does not result in a complete suction of the oil and

the task is consciously related to the application of a delivery of gas into the work area.

a level control for partially load-bearing or full-frame, because otherwise this gas in the work area

Gende F "derbeine with relatively little un- rise upwards, there on those not from the gas cushion

Differences between the lower and the upper 4 ^ loaded side of the work area and the

Limit load limited, for example to undesirably distort damping properties

For the purpose of temperature compensation and in the event of a form. For all of these reasons, this could

only a slight load dependency. did not know shock absorber be a teaching for the invention.

The problem posed is achieved in that the case of another from the French patent volume of the oil reservoir is only about as large as 45 font 1 261 449 known suspension strut by means of elects is like the volume difference of the gas cushion of a pump rod air from a storage container promoted in the gas spring space between a predetermined upper level in an air-filled working space, with ren and a predetermined lower limit load of oil in the work area, in the storage tank and in the Pumdcs Strut, so d.-ß when the upper penzyiinder is exceeded only serves to promote air The limit load is counteracted by a further upsetting by suctioning off a low pressure in the storage container to enable the oil from the oil reservoir and then a high pressure in the work area. Send per se known promotion of gas through Her outlet of the pump cylinder is at the highest Pump rod and arranged when falling below the lowest point. The storage container stands with Ren limit pollution a further downregulation through the atmosphere by one of a kickback cinen Pressure equalization between the working space and the 55 oil flap covered opening in connection. As soon as Reservoir are prevented, whereby uer outlet in the reservoir creates a vacuum, air of the pump chamber is sucked in from the af.nosphere in a manner known per se, with no defider is arranged at the highest point. no cessation of pumping occurs. This too

These measures can be used in a more advantageous known strut could not doctrine for the He way be a functionally reliable shock absorber with an easy 6 ° findiing.

Realize a structure that does not require expensive means.

required for separating oil and gas, neither in the derbein according to the invention when still exceeded

Gas spring space «, above the work space, still at the tenem nominal level in the oil storage space and in the work

the advantageous small-volume oil reservoir has the same pressure as the predetermined lower pressure room, and where the gas solution and outgassing 65 limit load is defined. The oil reservoir can be in

properties of oil useful for maintaining a gas- this state should be almost completely filled with oil, where-

pressure in the oil supply -mim can be used and only a small amount of free gas above the oil

Gas transport from the gas cushion into the oil supply is present and further gas is dissolved in the oil. As soon as

when the pump is operating below the target level, oil is sucked out of the oil reservoir, whereby Gas outgassed from the oil in the oil reservoir and a pressure above the oil that is sufficient is maintained to push the oil through the pump valves during the suction stroke of the pump. So far the oil is out sucked off the oil reservoir so that gas is now being pumped into the working space by the pump, This way, there are no disadvantages, since the pumped gas gets into the gas cushion of the gas spring chamber and takes part in the suspension there. Rather, there is the advantage of a defined termination of pumping, so that the load-bearing capacity of the strut can no longer increase and thereby the predetermined upper limit load is defined. If the target level is exceeded again, flows out from the working chamber into the oil storage chamber, in which a corresponding to the high pressure of the working chamber relatively large amount of gas is dissolved. A part of this oil gasses as a result of the lower one Pressure in the oil reservoir, the other part remains dissolved in the oil. If the target level remains exceeded, the shock absorber comes back to the regulated level described at the beginning of this paragraph Status.

In the case of the strut according to the invention, an advantageous circumstance which simplifies the assembly is to be found Mention that when filling with oil and gas, everything needed in the working space and in the oil storage space oil volume and the entire gas volume, each for itself or gas and oil together a single and arbitrary point of the housing can be introduced in one operation. To One-time pumping up to the upper limit load and one-time de-energizing immediately arises Desired distribution of the gas volumes in the gas spring space and in the oil storage space.

According to a further feature of the invention is in the axially adjoining the working space Gas spring space in the area of the surface between oil and gas, a separating body made of solid material arranged movably, the one by capillary forces with oil-filled annular cylindrical gap with the inner wall of the gas spring chamber and is secured against sinking into the oil chamber by means of props. Such separating bodies known from German patent specification 1 142 470 have the effect that the effectiveness the damping is not adversely affected by the tearing of the free surface of the oil in the gas spring chamber will.

In the drawings, exemplary embodiments of struts according to the invention are shown, namely shows

F i g. 1 a strut in longitudinal section with the room sequence work area. Gas spring space, oil storage space,

2 shows a strut in longitudinal section with the Room sequence oil storage room, work room, gas spring room,

F i g. 3 the end of a working piston facing a pump rod,

F i g. 4 the end facing a working piston a pump rod,

F i g. 5 shows the longitudinal section of a bottom end of a spring strut according to FIG. 2.

The spring strut according to FIG. 1, which has an outer tube 1 and a piston rod 2. 1 supports itself with a base 3 of the outer tube 1 on a vehicle body 4 and with the piston rod 2 on one Vehicle wheel 5, which is articulated to the vehicle body 4 by means of parallel links 6 and 7. The strut according to Fig.l is part-bearing and contributes together with a coil spring 8 a proportionate Fahrzcuglast. The outer tube 1 is closed by a cover 9, through which the piston rod 2 is sealed to the outside by means of a piston rod seal 10 occurs. A working piston 11 provided with throttle bores 16 is produced at the end of the piston rod 2 Damping forces in a working space 12 of the outer tube to which a gas cushion 14 Connect the receiving gas spring chamber 13 and an oil reservoir 15. Between work space 12 and Gas spring chamber 13 is a separating body 17 made of solid material known from German patent specification 1 142 470 Material arranged by a collar 18 on a pump rod 19 against sinking into the Working space 12 is secured. The hollow pump

ao rod 19 is attached to a partition 20, which at the same time the oil reservoir 15 of the gas spring chamber 13 separates pressure-tight. As a seal between the partition wall 20 and the outer tube 1 are a Sealing ring 21 and as a seal against the pump

»5 pen rod 19 not shown sealant known Art provided.

Et, * cavity 25 of the hollow pump rod 19 opens below the oil level in the oil reservoir 15 and has a check valve 22 and at its other end that plunges into the working space 12 a regulating opening 23. The pump rod 19 works with a pump chamber 24, which by the hollow piston rod 2 is formed, for level control together, for. B. in the context below with the description of FIGS Wise. In the drawn position of the working piston 11 there is an open connection of the Working space 12 with the oil reservoir 15 through the regulating opening 23 of the pump rod 19, where-

is possible through an exchange of volume between these two spaces until the pressure is equalized. In further In the retracted state of the working piston 11, the control opening 23 is not shown Means of the working piston 11 closed. Now, when the piston rod 2 is extended again, oil is in the pump chamber 24 of the piston rod 2 "is sucked out of the oil reservoir 15 and during the subsequent Retraction promoted through pressure valves (not shown) into the working space 12. To this The vehicle body 4 is pumped up.

With a medium load on the vehicle body, the static equilibrium position of the working piston may be 11 of the position shown at a maximum temperature of 70 ° C

to speak. When the vehicle is fully loaded, the working piston should compress by the amount A due to the spring stiffness of the hydropneumatic strut itself and the helical spring 8 and just cover the cut-off opening 23. When the vehicle is empty, the working piston 11 should spring by the same amount A. Under these assumptions, IA is the total static spring travel from empty to fully loaded at a damper temperature of 70 ° C. Experience has shown that the temperature of a damper with the long length shown does not exceed 70 ° C. If the temperature of the damper is 70 ° C of the steamer is lower, e.g. B. is at 20 ° C, ode also at degrees of cold, may in the fully loaded Zu

the working piston was touched by a dimension 2 A against part 245 and the entire separating body against

cinfedern the position shown. The pressure of the gas cushion now occurs in the gas spring space 213

the pumping action in action, the working piston shifts upwards.

(lcrt by 2/1 and stands when the piston is just closed. A working piston 311 according to Fig. 3 shows flow

Control opening 23 again in equilibrium, wöbe, 5 munpskaniilc 350 and 351 as well as valve plates 352

a relatively small amount of oil from the oil and 353 for the oil to flow through in both

Storage space 15 is pumped into the working space 12 in directions and is connected to a piston rod 302

the must. The entire area for the static position is screwed by a nut 354. In a I'iim-

kmg of the working piston 11 between empty and pcnraum 324 of the piston rod 302 protrudes a Stcucr-

The pumped-up, laden state is 355 for all IO sleeves, which is in accordance with the German interpretation

Temperature degrees 2 A and would be AA . 1 254 031 in a known manner in cooperation with

if a regulation were not in place. the pump rod 219 of FIG. 2 part of a pump

In the case of the strut according to FIG. 1 are in the picture and control device is. A spherical flange

Chen representation of the diameter of the piston 357 of the control sleeve 355 forms together with a

rod 2 and the volume of the gas spring space 13 15 plastic ring 356 a tight, side and carda-

as well as of the oil storage space 15 so that the joint can be displaced towards one another. The flange 357 and the

it is true that the usual spring characteristics result

ben would ben, while the length of the working space 358 against an end face 359 of the piston rod 302

12 is shown greatly abbreviated and pressed in one. The control sleeve 355 can counter the force

common strut three to four times longer ao lift off the conical spring 358 and as an exhaust valve

would have to. This is mentioned to serve the pictorial impression, being between the plastic ring 356 and

A very large length of the gas spring space 13 gives the flange 357 an opening. Besides that

Compared to the length of the working space 12 , it has a sharp control edge 361. In addition

then. or exclusively an exhaust valve 360 on

In the case of the strut according to FIG. 2 are a bottom 35 upper end of the pump room 324 and a very

203 of an outer tube 201 with the unsprung, closely held opening 362 can be provided through

Mass and a piston rod 202 with the sprung. the gas bubbles are ejected from the pump chamber 324

Mass attached to thinking. In the order of which can be.

from the bottom to the top are an oil reservoir 215, an end of a pump rod 419 according to FIG. 4th

Partition 220, a working space 212, a partition 30 has a preferably one in its cavity 425

body 217, a gas spring chamber 213 and a cover glued valve sleeve 470 , which together with

209 arranged one behind the other, the spring strut of a valve plate 471 forming a check valve

at no point does it have a larger diameter and serves as a suction valve in the form shown,

points than corresponds to the outer tube 201. A hollow when the pump rod into the control sleeve 355 after

Pump rod 219 protrudes into working space 212 and 35 F i g. 3 dips. One with consideration for a poss

opens at its end facing the base 203, which allows a long discharge time, very narrow regulating opening 423

240 below the oil level in the oil reservoir 215. of a very short length is in the jacket of the pump

The pump rod 219 has at the upper end a rod through one from the opposite side

Control opening 223 . Stepped bore drilled at the end of the piston rod. An opening 473

202 is a valve-equipped working piston 211, 40 the stepped bore is through the valve sleeve 470

stigt, whose extension stroke is blocked by a collar 241. A blockage in the control opening

a cylinder 423 surrounding the piston rod 202 is prevented by the fact that its axial length

throat neck 242 is limited. The gas spring space is small and parts sticking in it when slipped over

213 is through an annular space between the outer edge of the sharp control edge 361 of the control sleeve 355

tube 201 and the neck 242 is formed. In this 45 according to FIG. 3 sheared off and into the cavity 425

Annular space is the one to be pressed from the German patent specification.

1 142470 known separating body 217 arranged, between a bottom 503 and an intermediate

which consists of two parts 243 and 245 , which through wall 520 of the bottom end of an outer tube

a spring 244 are held together. The separator 501 according to Fig. 5 is an oil reservoir 51 ^ an-

The body 217 is arranged to prevent it from sinking into the work space 50. The partition 520 is by means of a

212 as a result of gravity and the spring force of a clamping ring 580, a washer 581, a sealing ring

light spring 246 through the collar 241 of the neck total 582 against one supported on the bottom 503

242 secured. Sleeve 583 clamped and opposite the outer tube

When the part 243 of the separator 217 is sealed to the 50I the partition 520 is in front

If the collar 241 is in contact, a pump rod 519 can penetrate the 55 when it is extended further. A collar

The piston rod 202 does not only support the oil through the gap between the flange 584 of the pump rod 519

see the part 245 of the separating body 217 and which is about an elastic ring 585 in the axial Rieh

Outer pipe 201 pass into working space 212 , device from partition 520 . The ring 58!

but also in that the part 245 against which also serves as a seal for the outer jacket de

The force of the spring 244 moves downward in the manner of a valve. 60 Pump rod 519 opposite the oil reservoir

away and an additional flow cross-section 515. To limit articulated mobility

releases. The part 245 of the separator 217 can serve as the pump rod 519 on the pumper

Hydraulic stops act when the working rod 519 is attached and opposite the sleeve 58

ben 212 when extending the lower face of the disc 586, which has little play.

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^r 'For this purpose, 2 sheets drawings

Claims (1)

3. Suspension strut according to claims I and 2, claims: characterized in that a collar (18) of the pump rod (19) serves as a support means. 1. Self-pumping hydro-pneumatic suspension strut with internal level control for driving 5 consisting of tools, in particular motor vehicles consisting of a cylindrical housing connected to the sprung or unsprung mass of the vehicle, an oil-filled housing a piston at the end of a sealed out of the Ge with the sprung or unsprung mass of the housing and connected to the unsprung vehicle connected cylindrical housing, or the sprung mass of the vehicle connected to a hollow piston rod in an oil-filled working space of the housing, an in a gas spring chamber attached to the x «, ses, with a damping mechanism, hung at the end of an arranged working piston, the oil in the working chamber via a seal led out of the housing and with a free surface between oil and gas under the ung sprung or the sprung mass of the pressure-setting gas cushion, a hollow piston rod connected to the vehicle, a piston rod outlet opposite ends ao arranged in a gas spring of the housing adjoining the work space, arranged through a space, the oil in the work space separated pressure-tight over the inner wall , against which a free surface between oil and gas is pressurized in a pressure-tight manner under the outside atmosphere, one end of the intermediate oil and gas arranged on the opposite end of the oil and gas and one between the intermediate houses and a partition wall sealed, penetrating hollow pump pressure-tight, separated from the outer breathing rod, which at its one end opens below the pressure-tight sealed oil reservoir of the oil level in the oil reservoir and at its other with a free surface between oil and gas A pump suction valve and one end that penetrates the partition in a sealed manner with a hollow pump rod extending into the hollow piston, which works together at one of the rods connected to the pump chamber to the level end below the oil level in the oil reservoir by opening out at the bottom and at its other end, with the pump exceeding the target level ir. Dependence on the suction valve, with a pump chamber arranged in the hollow piston rod from the oil storage chamber, which calls into the working chamber, while when the level control is exceeded, it cooperates when it falls below the Target level of oil can flow from the working step of the target level depending on the space in the oil reservoir, because spring movements oil from the oil reservoir into the characterized in that the volume promotes the working space, while when the oil reservoir is exceeded (15, 215 or 515) only the target level of oil from the work area into the The oil is selected to be about as large as the volume difference 40 storage space can flow off.