DE6609390U - HYDROPNEUMATIC SHOCK ABSORBER WITH SELF-ACTING LEVEL REGULATION, ESPECIALLY FOR MOTOR VEHICLES. - Google Patents

Description

PATENT LAWYERS

DR. ING. DiPL PHYSrH. S-TURlES I DIPL. ING. P. EICHLER

56 WUPPERTAL 2, BRAHMSSTRASSE 29

Jan. 18, 1972

Company August Bilstein, 5828 Ennepetal-Altenvoe ^ ds

"Hydropneumatic strut with automatic level control, especially for motor vehicles"

The innovation relates to a hydropneumatic spring strut with automatic level control, which is intended in particular for motor vehicles and which consists of a working cylinder filled with working fluid, a working piston guided therein with sliding displacement and with a piston rod sealing out at one end from the working cylinder, a compressed gas chamber that puts the working fluid in the working cylinder under high pressure , a partially filled with working liquid reservoir chamber and a valve is between the latter and the working cylinder situated ijj pump and a Abregel- ⁵ I for the working fluid.

S With the known hydropneumatic struts of the above type, the so-called self-pumping struts, the S | Relative movements occurring during the travel movement between the working cylinder and the piston rod are used to pump part of the working fluid from the storage chamber into the working cylinder for any level regulation so that a corresponding pressure increase occurs ₇ which leads to an increase in the piston rod exit force.

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A wide variety of pump designs are known for this purpose become, wherein the pump chamber is mostly located in the hollow piston rod and one therein more or less far retracting pump plunger is attached to the working cylinder base. As soon as by appropriate pumping the working fluid has reached the desired level, the pumping action is automatically interrupted. If the piston rod, E.g. after unloading the vehicle, moves too far out of the working cylinder, so the working pressure then closes is high, the regulating valve opens, whereby part of the working fluid flows back into the storage chamber and thus a corresponding decrease in pressure occurs in the working cylinder. However, all these previously known self-pumping hydropneumatic suspension struts have the essential deficiency that the automatic level control can only occur after sufficient movement or duration of the vehicle. With the vehicle stationary there is no level regulation. This is a serious one Disadvantage, v / eil associated with considerable dangers when starting the motor vehicle because of its excessive low position are. It should also be taken into account that even with vehicles that have only been idle for a few hours, the pumping struts because of the inevitable leakage or leakage losses at the liquid, in particular control valves lose piston rod exit force, hence the Suspension struts always have to be pumped up regularly when starting off.

In another known type of resilient motor vehicle support devices, each of which has several

Suspension struts combined to form a hydropneumatic composite system are encased by a pump and control system installed on the vehicle and thus brought up to or down level. can be maintained, the level control can also be carried out when the vehicle is stationary. However, require Such composite suspension strut systems include extensive hydraulic or compressed air lines between the vehicle and the individual Struts. These supply lines not only cause corresponding laying difficulties, they also require them also very careful maintenance and monitoring. In the event of line defects or if a shock absorber becomes damaged the entire line system must be interrupted or at several Places shut off, the pressure medium started and refilled again. All of this requires very cumbersome mid only repair work to be carried out in the workshop.

The innovation is based on the task of adding a hydropneumatic suspension strut with automatic level control create, like the ones described above, of a self-pumping design, i.e. as an independent individual support element is to be used, but can be brought to the desired level even when the vehicle is stationary. That will be seen in hydropneuraatis Struts of the type mentioned in the introduction are achieved according to the innovation in that the drive of the pump is carried out by an electric motor housed in the shock absorber, with a level switch installed in the power supply line. on In this way, you get a strut with a compact design that does not have any hydraulic or pressure medium lines leading to the vehicle and that even when the vehicle is stationary

can be brought to the desired level.

It is advantageous to connect the power supply line of the pump motor to a power source located in the vehicle and to connect the Level switch built into the part of the power supply line located in the shock absorber. Such a strut can therefore as Independent support element like a normal shock absorber installed or exchanged in the vehicle, whereby only the power cable with the power supply on the vehicle side Needs to be connected via a simple electrical plug, so no further supply lines are necessary are. Due to the level switch built into the part of the power supply on the spring strut side, the When the vehicle is loaded, it ensures that the latter always drives in a wood-zontal position, v / eil each spring strut individually adjusts to its level to control the pump drive motor by the same level switch. This is how the high- as is done also raining down to the desired level through purely electrical Control depending on the switch that responds to the respective level position.

To with the relative movements occurring between the working cylinder and the piston rod during driving repeated short-term switching on of the pump drive motor as well as the cut-off valve According to a further feature of the innovation, to be avoided are those from the level switch to the power supply lines of the pump drive motor and / or the electrical control lines leading to the electromagnetic cut-off valve

built. Instead of such electrically working delay relays but the level switch can also be designed, for example connected to a damping control ring, that the switch itself already responds with a corresponding delay, therefore due to the relatively short-term Vibrations between the working cylinder and the piston rod of the fader leg remains unaffected and therefore only on actually responding level shifts.

E ¹ There are various possibilities for the design and arrangement of the level switch and the pump drive motor, of which particularly advantageous ones are shown in the several exemplary embodiments reproduced drawings. It shows:

1 shows a first embodiment of the new Fedex leg

in axial longitudinal section,

2 shows a hollow piston rod with a level switch and associated control means housed therein,

FIG. 5 shows a partial view of the suspension strut with an electromagnetically actuated cut-off valve housed in the base of its working cylinder, FIG. 4 shows a partial sectional view of a suspension strut

with a pump with drive motor flanged to the side of its outer cylinder jacket,

Fig. 3 is a partial sectional view of another strut embodiment in which the level- * control is cylinder via the working piston and the working «·.

Ι Ι

· * · Nid

6 shows a partial section through another

Strut embodiment with one in the ρ hollow piston rod housed | Level switch that is activated with a I gerprinzip working control piston is provided, and

Fig. 7 shows a further embodiment of a spring strut J in axial longitudinal section, "wherein the built in the I hollow piston rod by a level switch Dämpfungssteüerkölben with YsrSvgs = approximate effective to actuate is.

The irc Fig. 1 shown hydropneumatic spring strut consists essentially of the outer cylinder 1 and the inner tube 3 used therein, forming the working cylinder 2, with the bottom piece 4 closing the latter and the closing cover 5 through which the piston rod 6 is sealingly passed, which is connected to the working piston 7 carries its inner end. The annular space present between the inner tube 3 and the outer cylinder jacket 1 is divided axially by the permanently installed partition 8. Between the partition 8 and the bottom piece 4 protruding radially over the inner tube 3, the storage chamber 9 partially filled with working fluid is provided, while the annular space 10 located above the partition 8 communicates via the connecting channels 11 with the working cylinder i 2 and, like the latter, with Working fluid is full. The working fluid in chambers 2 and 10 is under the action of the pressurized gas housed in chamber 12, which is released from the ring «

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- ■ · ■■ '■■ · ■ ■■: ■ M

'Γ I; ι space 10 is separated by the hose membrane 13. The working piston 7 is designed as a damping piston and for this purpose with two alternately effective in both directions Throttle openings 14 provided, which are covered by the valve spring washers 15 or to be controlled.

In the bottom piece 4, the pump tappets 17 are slidably mounted in radial bores 16, with their heads 17 'by the springs 18 in contact with the correspondingly shaped, z, B. with cams 19 provided shaft end 20 of the arranged below the bottom piece 4 electric motor 21 to hold cind. At their outer ends, each forming small pump chambers, the radial bores 16 are each provided with a suction valve 22 provided suction line 23 with the storage chamber 9 and a line 25 provided with the outlet valve 24 with connected to the working cylinder space 2. For the sake of clarity, only the suction line is shown in the right-hand pump chamber in FIG. 1 23 ″ and only the outlet line 25 is shown in the left pump chamber.

• Furthermore, the regulating valve, not shown in FIG. 1, is provided in the base piece 4, which valve can be of the nature shown in FIG. 3. The regulating valve here consists of the valve line 26 connecting the working cylinder chamber 2 to the storage chamber 9 and the valve body cone 27 'which, with its valve stem 27 ^{f, interacts} with the conical "circumference of the sliding armature 28 of the electromagnet 29. In the position of the sliding armature 28 shown, the valve cone ^{27 pressed} against the valve seat surface by the leaf spring -27 lf attacking it.

The level-dependent control of the pump drive motor

21 as well as the cut-off valve 26 to 29 is carried out by a

Level switch built into the shock absorber and delay relay built into its control line. In the example shown in Fig. 1, right-mentioned embodiment, the level is, switches from a plurality of surviving in series or stacked switching contacts 30, 31 and 32 'wherein the switching contact 30 aiii the at the free piston rod end β ¹ seated attachment plate 33 attached to the bellows 34 is, while the switching contacts 31 and 32 are fixed in the folds of the bellows 34 in a suitable manner. Väirend the middle switching contact 31 is in constant electrical connection with the power source located on the vehicle, the contact 30 is connected to the control line leading to the electromagnet 29 of the regulating valve 27 and the contact 32 is connected to the control line leading to the pump drive motor 21. Delay relays (not shown) are built into the relevant control lines.

In the fully shown in Fig. 1, the desired level position corresponding position of the piston rod 6 is the Power line between the switching contacts 31 and 32 interrupted, so that the pump drive motor 21 comes to a standstill. Against it the control line leading to the solenoid valve 29 is transferred from the switch contacts 30, 31 in this position Current flows through it, whereby the regulating valve 27 is kept closed. If the strut is dashed as in FIG. 1 The position shown of the piston rod or its fastening plate 33 is retracted too deep, close the. Switching contacts 31, 32 also lead to the pump drive motor 21 Control circuit so that the motor 21 starts. He drives

: sfltissisksit from the

the pump tappets 17, whereby work Storage chamber 9 is pumped into the working cylinder space 2, consequently a corresponding pressure increase takes place here * the leads to the fact that the piston rod 6 extends into the desired level position in which by opening the contacts 31, 32 of the Motor 21 is switched off again. If the piston rod 6 extends too far, for example after unloading the vehicle, you Fastening plate 33 so in the Pig. 1 reaches the top right dot-dashed position is over the then diverging Contacts 31, 30 also the control circuit leading to the cut-off valve - interrupted, so that the cut-off valve 27 opens, consequently a corresponding amount of working fluid from the working cylinder space 2 into the antechamber can escape. The delay relays built into the control lines each cause the pump drive motor .21 and also the regulating valve 29 always only respond when an effective level control is necessary, such as when starting or loading or unloading the vehicle.

As shown in Fig. 1 top left, the various switching contacts of the level switch can also be accommodated in a correspondingly designed micro switch 35, between two adjacent turns of a flat spring 36 installed \ * can be grounded between the mounting plate the piston rod 6 and the cap 5 of the working cylinder is arranged.

In the embodiment shown in Fig. 2, the level switch consists of a hollow in the Piston rod 6 housed microswitch 35, its in

three different switch positions to bring the switch plunger 35 'housed by ± i of the piston rod, with the opposite one Arbeitszyliiiderboden 4 connected control means is to be operated. For this purpose is on the bottom piece 4 of the working cylinder the control rod 37 is fastened, which is passed through the piston rod bore 39 at the point 38 in a sealing manner is and at its inner end a spring plate 40 on which there are two concentrically arranged helical springs 41, 42 are located. The externally arranged spring 41 is of lesser strength than the inner spring 42, which is also axially r-oeh is kept a little shorter. Between the two feathers 42 and the switch plunger 35 'is still in the interior of the piston rod the control piston 43 is provided, which is held or guided by the built-in web 44 to a limited extent, axially displaceable is. In the illustrated position of the control rod 37, which corresponds to the desired level position, the switch plunger 35 'is held in the central switching position via the control piston 43 by the spring 41, the spring 41 having the effect compensated for the switch plunger spring, not shown. When the vehicle is loaded, the control rod 37 penetrates accordingly deeper into the piston rod 6, as a result of which the inner stronger spring 42 now also strikes the control piston 43 and thereby displaces the plunger 35 'against its spring action. This causes the pump drive motor 21 to start. When the vehicle is unloaded, the control rod 37 retracts corresponding piece from the piston rod 6 from, v / o is relaxed so far by the spring 41 that now the switch plunger 35 'under the action of its inner spring ± i its from the micro-

switch housing reaches the furthest extended position, In the the cut-off valve 27 is opened.

In the control example shown in Fig. 5, the working piston 7 and the piston rod 6 are designed to conduct electricity to form the level switch, while the dumbbell tube of the working cylinder 2 is divided into three axially one behind the other, electrically isolated dumbbell zones 45, 46 and 47, of which the Piston rod outlet end facing jacket zone 45 with the power supply line 45 'to the electromagnetic cut-off valve 27, 29 and the jacket zone 47 facing the working cylinder base with the power supply line 47 ^! is connected to the pump drive motor 21. The plastic rings 48 and 49 effect the isolation of the individual pipe jacket zones and are firmly enclosed by the cylinder 50. When the piston rod 6 with the piston 7 moves into the area of the jacket zone 47, the pump drive motor 21 is switched on via a time relay until the level is reached, i.e. the piston 7 has returned to the area of the de-energized jacket zone 46. The curtailment occurs when the piston rod 6 is extended too far, as soon as the piston 7 has reached the jacket zone 45 and the curtailment valve 27 has thereby been opened via the time relay. The piston rod 6 is passed in an insulated manner through the plastic-coated guide 51 seated in the closure cover 5.

Fig. 6 shows a control in which the attached to the bottom piece 4 of the working cylinder 3 control rod 52 to the Point 53 guided into the piston rod interior 6 'in a sealing manner is, the control rod 52 depending on its depth of penetration by corresponding displacement of the piston rod

internal liquid which is affected by the back spring 54 standing, sealed guided displacement piston 55 moves that with the switch plunger 56 of the microswitch 57 is connected. The switching plate 56 'of the plunger can, as indicated, - again with the one on the vehicle side Be connected to the power source leading supply line, while the switching contact 58 to the pump motor and the Switching contact 59 are connected to the control line leading to the control solenoid valve 29. If the compression of the Piston rod 6 is driven by the control rod 52, which is immersed deeper, and the resulting displacement of liquid in space 6 ' the displacer piston 55 moves accordingly upwards, so that the switching plate 56 'with the switching contact 58 in contact comes and thereby the pump drive motor 21 switches on. As soon as the level is reached, the circuit board takes 56 'a middle position between the contacts 58 and 59. If the piston rod 6 and thus also the control rod 52 extends too far, the displacement piston is displaced in the process down until by closing the circuit board 56 'and the Switching contact 59, the regulating valve 27 is opened. As Fig. 4 shows, the electric motor 21 with the associated, analogous to the pump device provided in FIG. 1, also on the side of the outer cylinder jacket 1 of the strut be flanged. Since there is always space to one side of the shock absorber, its main mass can be attached to the Body to be attached. The side flanges of the motor 21 and the pump allow a short construction of the Strut, since its axial extension then only through the

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Length of the working cylinder 2 is determined. The connection of the pump suction line 23 to the storage chamber 9 and the pump outlet line 25 to the annular space 10, which is connected to the working cylinder space 2 via the opening 60, takes place via annular channels 61 or 62 worked into the outer cylinder jacket 1 and the corresponding connection ^{bores 61 f} büw. 62 '.

The strut shown in Fig. 7 is similar to that shown in Fig. 1, the matching Parts are provided with the same reference numerals. Here, however, are the means used to regulate the level of fundamentally different nature and mode of operation than doing without the use of delay relays built into the electrical control lines can be. So here is in the constantly connected with the working cylinder chamber 2 cavity 6 'of the piston rod a damping control piston 63 displaceably mounted, the one hand with the switch plunger 35 'of the microswitch is connected via the linkage 64 and on the other hand via the compression spring 65 and the tension spring lying one behind the other 66 is in positive connection with the base piece 4. This protrudes into the interior 6 * of the piston rod 6 on the bottom piece 4 attached guide tube 67, which is partially surrounded by the tension spring 66 uad by the compression spring 65. Both Springs 65 and 66 are connected to one another via the guide sleeve 68, which is slidably seated on the guide tube 67. If the level shifts, either the force of the compression spring 65 or that of the tension spring 66 acts on the damping 63, or depending on the setting of the damping

displacement force correspondingly delayed and thereby adjusts the switch plunger 35 ', the contact plate 35 "of which either closes the switch contact 35''' leading to the pump drive motor 21 or the switch contact 35 '' · 'leading to the regulating magnet 29. The desired middle or level position is achieved the balance of forces of the tension spring ββ or the compression spring 65 and is determined by the zero position of the microswitch 35. The spaces 6 ', 6 "and 2 filled with working fluid are under constant pressure equalization of the respective strut load. In the middle or level position shown, the tension spring 66 is normally on the block. If the piston rod 6 compresses too much, the damping control piston 63 is therefore slowly moved upwards by the tension spring 65, which is then more strongly compressed, so that it moves over the switching contacts 35 'which then close. 'and 35' ^l! the pump drive motor 21 turns on. On the other hand, starting from the illustrated central position, if the rebound of the piston rod 6 is too strong, the tension spring 66 then moves via the guide sleeve 68 and the compression spring 65 of the damping control piston 63 downwards, whereby the switching contacts 35 ^l! and 35 "" the regulating valve 27 is opened.

It goes without saying that within the scope of the present innovation numerous modifications are possible, in particular with regard to the level control and design of the pump drive motor. For example, the latter can also be in the form of an electric vibrator that directly drives the pump plunger drives.

Claims (13)

■ "■ claims for protection; 1. Hydropneumatic suspension strut with automatic level control, in particular for motor vehicles, consisting of a working cylinder filled with working fluid, a working piston guided in it slidingly displaceable at one end the working cylinder sealing out piston rod, one of the working fluid in the working cylinder under high Pressurized pressurized gas tank, a storage chamber partially filled with working fluid and one between the latter and the working cylinder located pump and a regulating valve for the working fluid, dadvrch. marked, that the pump (16, 17) is driven by an electric motor (21) housed in the strut takes place, in whose power supply a level switch (e.g. 35) is installed. 2. Hydropneumatic strut according to claim 1, characterized gekennze i chne t that the power supply of the pump drive motor to a power source located in the vehicle to be connected and the level switch (35) is installed in the part of the power cable located in the shock absorber. 3. Hydropneumatic strut according to Claims 1 and 2, characterized in that the regulating valve (27, 29) can be actuated electromagnetically and, like the pump drive motor (21), can be controlled by the same level switch (35). 4. HydropneTjjnatisches strut according to claims 1 to 3, characterized in that in the from Level switch (35) to the power supply lines of the pump drive motor (21) and / or the electromagnetic cut-off valve (29) leading electrical control lines delay relay are built in. 5- Hydro-pneumatic spring strut according to claims 1 to 4, with a bellows or a flat spring which is provided between the working cylinder and a fastening plate attached to the free piston rod end and surrounds the piston rod, characterized in that the level switch consists of several in series one behind the other or one above the other arranged switching contacts (30,31,32), which are either mounted in the folds of the bellows (34) or a ^f ü fastening plate (33) or housed in a microswitch (35) located between two adjacent turns of the flat spring (36) . 6. Hydropneumatic strut according to claims 1 to 4, characterized in that the working piston (7) is conductive to form the level switch and the dumbbell tube (3) of the working cylinder three axially one behind the other, Has jacket zones (45, 46, 47) which are electrically isolated from one another, of which the piston rod exit end facing (45) with the power supply to the electromagnetic cut-off valve (29) and the bottom of the working cylinder (4) facing (47) with the power supply to the pump drive motor (21) is connected (Fig. 5). 660933018.5.72 7. A hydropneumatic strut according to claims 1 to 4, characterized in that the level switch consists of a microswitch (35) housed in the piston rod (6), the switch plunger (! 55 *) of which in drsi different switching positions to be brought through in the hollow Piston rod (6) housed and connected to the opposite working cylinder base (4) ^? S-control means (e.g. 37 _y 40 to 43) is to be operated, 8. A hydropneumatic strut according to claim 7, characterized in that a control rod (37) fastened to the Buden (k) of the Αϊ— beitszylinders (2) sealingly protrudes into the interior of the piston rod, at its inner end a spring plate (4θ) on which support two concentrically arranged helical springs (41, 42) of different spring strength, which; depending on the penetration depth of the control rod (37) via an interposed, axially displaceable control piston (43) in the piston rod (6), the switch plunger (35 ') of the microswitch (35) act differently (Fig. 2). 9. Hydropneumatic strut according to claim 7, characterized in that a control rod (52) fixed to the bottom (4) of the working cylinder (2) ^{sealingly protrudes into the piston rod interior (6 T} ), which depending on its binding ring depth by corresponding displacement of the piston rod interior Liquid moves a displacement piston (55) which is under the action of a return spring (54) and which is connected to the switch plunger (56) of the microswitch (57). (Fig. 6) • «C - 18 - 10. A hydropneumatic strut according to claim 7, characterized in that ^{a damping control piston (63) is displaceably mounted in the cavity (6 1} ) of the piston rod (6) filled with working fluid, which on the one hand with the switch plunger (35 ¹ ) of the microswitch (55) is connected and on the other hand via a compression and tension spring (65 or 66) lying one behind the other in a force-locking connection with the working cylinder base (4) (Fig. 7). 11.Hydropneumatisches strut according to claim 10, characterized in that at the bottom (4) of the working cylinder (2) in the piston rod interior (6 ¹ ) protruding guide tube (67) is provided, which of the tension spring (66) and partly of the Compression spring (65) is surrounded, and both springs (65,66) are connected to one another via a guide sleeve (68) which slides on the guide tube (67) (Fig. 7). 12. Hydropneumatic strut according to one or more of the claims 1 to 11, characterized in that the working cylinder consists of an inner tube (3) and one with it connected, radially projecting bottom piece (4), which are inserted into an outer cylinder (1), wherein in the bottom piece (4) the pump (16, 17) and the pump drive motor in the space between the base piece (4) and the outer cylinder base (21) are accommodated, while the annular space located between the inner tube (3) and the outer cylinder jacket (1) through a solid partition (8) into the storage chamber (9) and into one with the working cylinder interior (2) in a liquid-conducting manner connected annular chamber (10) is divided axially into 660839018.5.72 the the like by a sealing membrane (13). separated compressed gas chamber (12) is located. 13. Hydropneumatik.es suspension strut according to claim 12, characterized characterized in that the pump motor shaft (20) protrudes into a recess provided in the base piece (4) and is provided with drive cams (19) which are displaceably supported in radial bores (16) of the base piece (4) Pressurize the pump tappet (17). 14 »Hydropneunsbian strut according to one or more of the Claims 1 to 11, characterized in that the pump and its drive motor (21) on one side the outer cylinder (1) encompassing the working cylinder jacket (3) at a distance are flanged and the outer cylinder jacket pump suction and discharge lines passed through (23 or 25) in the storage chamber (9) located between the two cylinder jackets (3, 1) or in one which is sealed by a Membrane (13) or the like. containing a separate compressed gas chamber (12), which conducts fluid with the working cylinder interior (2) connected annular chamber (to) open (Fig. 4).