DE2911768A1 - Vehicle hydraulic shock absorber cylinder - is adjustable by means of internal solenoid valve - Google Patents

Abstract

An adjustable shock absorber (1) is installed in a vehicle suspension system. A cylinder (2), filled with a damper fluid, is divided into two chambers (6, 7) by a piston (8) which is attached to the inner end of a hollow piston rod (13). The upper end of the hollow piston rod locates a solenoid assembly (20, 21) which is attached to a valve piston (23) at the lower end of the hollow piston rod. Thus by operating the solenoid, the two cylinder chambers (6, 7) can be linked or isolated from each other.

Description

The invention relates to an adjustable shock absorber, in particular for motor vehicles, consisting of a filled with a damping fluid Cylinder in which a hollow piston rod that is axially displaceable therein immersed, in which a control means is arranged and at its end one against the disk, sealed off from the cylinder wall, carries the cylinder space in two chamber halves divides and has the directional high and low pressure valves for connection of the two halves of the chamber for the damping fluid after the closing force has been twisted of the valves.

A variety of shock absorbers have become known, including Infinitely adjustable or controllable shock absorbers are already known. The DE-OS 15 05 497 includes e.g. B. a continuously adjustable shock absorber, in particular for motor vehicles, consisting of a cylinder filled with damping fluid, a hollow piston rod arranged displaceably therein with therein housed control means and a working piston with two arranged in it Groups of axially extending liquid passage channels is provided by which each group on the outlet side by preferably on its inner circumference firmly on Piston clamped valve spring plates is covered, with at least one valve plate package by a contact pressure which can be regulated by the control means on its outer circumference adjacent support piston is supported. The one penetrating the hollow piston rod Control means acts directly on the support piston, the contact pressure of the support piston regulated independently of the hydraulic conditions prevailing in the damper can be. However, the design used here to regulate the shock absorber is not very effective. Because there is still a superposition of the damping influences one, making an accurate and flawless stepless damping adjustment not. is possible.

In another known adjustable shock absorber of this type according to the German patent application a 81 235 I1 / 63 c and B 82 476 II / 63 c takes place Regulation of the support piston or pistons resting against the valve spring plate assemblies for the purpose of Resetting of the damper setting by means of a hollow piston rod arranged adjusting rod through which throttle openings leading to the support piston more or less wide open and by the hydraulic that is set in the process Flow pressure or dynamic pressure on the support piston with regard to their contact pressure the valve spring plate can be regulated. The control of the support piston takes place here thus depending on the hydraulic conditions prevailing in the damper. Such a control of the damping resistance also leads to superimpositions the damping effects. The attenuation caused by the different placement of the am Working piston clamped valve spring plates is effected, the superimposed contact pressure of the support piston or pistons depending on the respective dynamic pressure conditions. This results in greater inaccuracies for today's motor vehicle construction are no longer tolerable. Furthermore, the use of the support piston is disadvantageous.

DE-OS 16 55 647 is also a controllable hydraulic Telescopic shock absorbers, especially for motor vehicles, have become known with a control element located outside the damping body via a transverse and / or an axial bore in a piston rod communicates. Within a control room, through a cylindrical widening of the axial bore at the end of the piston rod is formed, are a control sleeve and a control piston between spring elements and arranged a stop. This arrangement works like the ones previously mentioned, purely hydraulically. In order to control or regulate the shock absorber from the outside in disadvantageously an additional hydraulic medium are fed. For that you have to outside additional units are made available, so z. B. to generate pressure, which makes an additional effort that is no longer justifiable today.

Furthermore, DE-OS 24 41 174 is a wheel suspension for Land vehicles become known, with a between the carrier and the body hydraulic damping device, a displacement converter and an acceleration converter are arranged on the vehicle body. The displacement transducer produces a first Signal corresponding to the position of the wheel carrier opposite the body, the Acceleration converter on the vehicle body generates a second signal, which corresponds to the vertical component of the acceleration of the body at the wheel. In addition, there is a control device which is used to change the damping force the damping device in function according to the first and the second signal can be set so that the second signal from the acceleration converter has a setpoint value is caused to assume as a function of the first signal. To this end, the control device a function generator to which the first signal is fed at an output terminal and which generates an output signal that corresponds to a setpoint value of the second signal corresponds, wherein a comparator is provided, which corresponds to the damping device the error between the second signal and the output signal from the function generator controls.

The disadvantage of this hydraulic damping device is that normalize the two signals from different attenuators will must and the control signal in turn fed to two different damping devices will.

The invention is therefore based on the object of a shock absorber of the type mentioned at the outset to create its damping characteristics in addition is electrically adjustable, with all parts necessary for regulation or control inside the shock absorber - except for an electronic amplifier or a electronic signal transmitter -integrated should be arranged.

The solution to this problem is that according to the invention in the upper Part of the piston rod is a coil, within which an armature is movable is arranged, the axially facing end at its cylinder, the control means forming control slide carries within the axial longitudinal bore of the piston rod Is arranged slidably and the opening of this opening into the lower chamber half LänSsbohrung closes, the longitudinal bore in the area of the upper chamber half is penetrated by a cross hole, which is in the rest position / working position of the control slide is closed by this or vice versa.

The coil advantageously has an electrical supply line from outside the shock absorber.

The shock absorber according to the invention has the salient advantage that this can be applied to the shock absorber from the outside via control signals or switching pulses changed in its damping characteristics and adapted to the respective conditions can be. Advantageously, all of them are used for open-loop or closed-loop control necessary aggregates - except of course an electronic one that may be necessary Amplifier or an electronic signal transmitter - integrated within the shock absorber, this can nevertheless retain the same dimensions as known shock absorbers of the state of the art.

Advantageously, the coil within the inventive Shock absorber via the external supply line control signals or control pulses or rule pulses are supplied, so that according to these pulses the armature more or is less immersed in the coil and thus the control slide attached to the armature the lower opening of the longitudinal bore within the piston rod more or less releases. By releasing the longitudinal bore, an additional connection is created created between the lower chamber half and the upper chamber half of the cylinder bypassing the known valves within a shock absorber. This longitudinal bore the piston rod in cooperation with the transverse bore penetrating the longitudinal bore thus represent a bypass that is controlled or regulated by the control slide is lockable and openable. The bypass can either be in unloaded operation be open or closed.

In a further embodiment according to the invention, the longitudinal bore can be a blind hole within the piston rod, with within the end wall the piston rod has an axial through-hole with a smaller diameter than the diameter the longitudinal bore is arranged, through which through bore the transverse bore is guided, wherein the control slide with its lower end in the through hole immersed and can also be spring-loaded. The spring can be on the one hand on the end wall or on the bottom of the piston rod and on the other hand on one Support the holding member on the control slide. In that the longitudinal bore is within the piston cover is a blind hole into which a central through hole opens, becomes more advantageous Way, a guide for the control slide created within the piston rod. At the same time, space is created for the arrangement of a spring to the control slide and thus the armature within to hold the coil in a defined basic position.

In a further, highly inventive embodiment, the lower End of the control slide have a longitudinal bore in the area of the longitudinal bore the piston rod is penetrated by a transverse bore, so that the longitudinal bore of the The piston rod and the interior of the coil are filled with damping fluid. It is thereby achieved in an advantageous manner that the control means - be it in the Working position or in the rest position - is always under the same pressure as the upper half of the chamber of the cylinder. In particular, this also prevents that the control means, the armature together with the control slide, an undefined position can take. Due to the spring loading of the control spool and the armature and by filling the interior of the piston rod and the coil with damping fluid of the pressure of the upper half of the chamber of the cylinder is thus any false influence prevented by various pressures within the piston rod and the chamber system.

In a further, preferred embodiment of the invention, a adjustable telescopic shock absorber with a cylindrical one that extends over the cylinder Find pot use, which carries the piston rod centrally on the inside, the cylinder has a permanent magnet at its upper end on or in the outer wall and a coil is arranged on the cylindrical inner wall of the pot in the axial direction can be that has a feed line to the outside. The permanent magnet can be a ring magnet be, which is arranged on or in the jacket of the cylinder.

This embodiment of the invention is highly advantageous Way a fully adjustable (or controllable) telescopic shock absorber to disposal. Because inside the coil or the coils of the pot are through the ring magnet (s) of the cylinder when the telescopic shock absorber is alternately loaded one or more voltages induced over which all the data required to adjust the Damping properties can be derived from the respective state of the shock absorber can.

These data are amplitude, slope, acceleration, and frequency Direction. This data can be evaluated in a computer, which in turn is a generates an output signal corresponding to the current state of the telescopic shock absorber, which is fed to the coil within the piston rod of the shock absorber as a control signal will.

Furthermore, the telescopic shock absorber according to the invention can be used as a controller can be switched with special properties, in which this the output signal the coil inside the pot as an input signal after amplification and analysis for the coil is fed inside the piston rod.

In particular, it is possible with the telescopic shock absorber according to the invention, this according to the originating from the pot-type reel-cylinder magnet encoder system Regulate signal. Therefore, the telescopic shock absorber of the present invention can be practical respond immediately to any type of ground or to any driving behavior and Correct its characteristics accordingly for optimal driving behavior or support.

This telescopic shock absorber according to the invention is also highly advantageous fully integrated, d. that is, all for regulation or control necessary resources - except of course an electronic computer and evaluator and possibly an electronic amplifier - lie inside the shock absorber. Compared to the appearance of a conventional one Telescopic shock absorber the telescopic shock absorber according to the present invention differs only in that that this additionally has several external, electrical supply connections.

Furthermore, the shock absorber according to the invention as well as the inventive Telescopic shock absorber, be provided with a switch that can be used, for example, during load operation of the vehicle only switches the bypass within the piston rod on or off. As a result, in the simplest embodiment of the shock absorber according to the invention, a Shock absorbers can be obtained for two driving operations, namely for load operation and for normal operation.

Furthermore, it is possible within the lopfes a coil with z. B. to provide only a single turn, which serves as a limit indicator and which is therefore arranged in or on the end of the pot. Will then about this If a signal is given to limit switches, the telescopic shock absorber turns into a harder one Operation switched.

In a further advantageous embodiment, inside the pot two coils can be arranged, which have two separate leads to the outside. For this purpose, the cylinder has two permanent magnets, in particular ring magnets, on its outer jacket on, which are offset with respect to their distance that when immersed into the coils of these two signals that are 900 out of phase are. In this case, the respective direction in that the shock absorber moves can be discriminated against.

The invention thus provides an adjustable shock absorber for the first time available, which is only available via externally supplied electronic switching signals or Impulse can be regulated, with all parts necessary for regulation within the shock absorber integrated are and which this is thus in its appearance of ordinary shock absorbers do not need to be distinguished.

The invention is with further details and advantages in the following Description based on four exemplary embodiments shown in the drawing explained in more detail. They show: FIG. 1: a cross section through an inventive Shock absorber, consisting of a cylinder with a cylindrical one slipped over it Pot Figure 2: a section along the line A-A in Figure 1 to illustrate the transverse bore inside the piston rod Figure 3: another example of one according to the invention Telescopic shock absorber, with the pot and the cylinder additionally as electric Encoder system designed sinC Figure 4: an embodiment according to Figure 3, whereby the coil in the pot only has a single turn and serves as a limit value transmitter and FIG. 5 shows another example of a telescopic shock absorber according to the invention each with two coils and two permanent magnets for directional discrimination.

In the figures, the same parts are identified by the same reference symbols.

According to Figures 1 and 2, the adjustable shock absorber 1 consists of a lower, cylindrical part 2, which is filled with a damping liquid and an upper, cylindrical pot part 3 which overlaps the cylinder 2. At the upper end of the pot part 3 as at the lower end of the cylinder 2 are each one Bracket 4, 5 arranged for fastening the shock absorber 1 on the one hand to the body and on the other hand on the wheel or on the wheel axle.

A hollow piston rod 13 is arranged centrally within the pot 3, which thus has a through hole 19. The piston rod 13 is inside a cover 17 guided centrally and sealed, the cover 17 the cylinder 2 locks.

A ring seal 18 seals the cover 17 against the piston rod 13 from. Located at the lower end of the piston rod 13 immersed in the cylinder 2 a disk 8 which is firmly connected to the piston rod 13. This disc 8 is slidably disposed within the cylinder 2 and opposite the cylinder wall suitably sealed. In the example shown in Figure 1, the disc 8 is means a washer 16 and a nut 15 that fit onto the lower end of the piston rod 13 is screwed on, firmly held. The disc 8 also has its both planar main surfaces each have a spring assembly 11, 12, which through bores Cover 9 and 10 within the disc 8.

The springs can e.g. B. have different spring values, whereby the disk 8 represents a high pressure and low pressure valve. The pot with the The piston rod and the disk attached to it is now relative to the cylinder movable. The disk 8 thus divides the cylinder space into two chamber halves 6 and 7, which through the valve holes 9, 10 are in communication with each other.

In the upper part of the piston rod 13 there is now a coil 20 in the longitudinal direction arranged, which receives an armature 21 in its interior.

The lower end of the anchor 21 has a conical taper, which engages in a conical holding part 22 arranged at the lower end of the coil 20. This creates a defined end position of the armature 21.

The armature 21 is at its lower, tapered end with a control slide 23 connected, which is also within the longitudinal bore 19 of the piston rod 13 extends. In the example shown here, this longitudinal bore 19 is a blind bore, a through hole 31 being guided centrally through the lower end. Of the The diameter of this through hole 31 is smaller than that of the longitudinal hole 19. Furthermore, a transverse bore 30 through the transverse to this longitudinal bore 31 Piston rod guided, with this transverse bore 30 in the area of the upper chamber half 7 of the cylinder 2 is located. The control slide 23 now dips into the through hole 31, whereby the control slide fits into the through hole. The control slide 23 is further biased by a compression spring 24, which on the one hand attaches itself to the end wall 26 of the blind bore 19 and on the other hand on a fixed to the control slide 23 connected holding part 25 is supported. The holding part 25 can, for. B. a mother or be a transverse pivot. By the compression spring 24, the control slide 23 and the armature 21 is pressed into a defined position, in the example shown in FIG up.

The coil 20 also has an outwardly leading supply line 32, this supply line being isolated within the shock absorber. Further the shock absorber can have a ground connection 33.

The control slide 23 also has at its lower end a longitudinal bore 27 running in the axial direction, which is located in the region of the longitudinal bore 19 or the blind bore is penetrated by a transverse bore 28, 29. This is the entire interior of the piston rod 13 is filled with the damping fluid, which is always under the same pressure as that within the upper half of the chamber 7 prevails. As a result, the armature 21 together with the control slide 23 always takes one defined position, whereby this position is not due to different pressures within the system is affected.

The mode of operation of the shock absorber shown is as follows: In the In the rest position of the armature 21 and the control slide 23, the shock absorber works like an ordinary shock absorber. The bypass, formed by the through hole 31 and the transverse bore 30 within the piston rod 13 is either closed or opened; In the example shown here, the bypass is open in the rest position. In this case, the damping of this shock absorber is thus set to be soft.

If a current is now sent through the coil 20 via the supply line 32, so the armature 21 is completely in the coil 20 due to the magnetic field drawn in, whereby the lower end of the control slide 23 in the through hole 31 retracts and blocks the transverse bore 30 running to it. This allows the Sudden bypass are closed, thereby reducing the damping characteristics the shock absorber can be changed suddenly. In the example shown here the shock absorber 1 is thus switched to "hard" operation.

Figure 2 shows a side view of the piston rod 13, with the disc 8 is shown in a partial section. From Figure 2 is the course of the transverse bore 30 transversely to the through hole 31 can be seen. The transverse bore 30 is elongated here Executed slot.

Figure 3 shows another embodiment of an adjustable telescopic shock absorber, again consisting of a cylinder 2 with a cylindrical one arranged above it Pot 34, which overlaps the cylinder 2 downwards. This pot 34 points to his Inner wall an axially aligned coil 35, this coil z. B. off a single-layer turn can exist. The coil 35 has a leading to the outside Feed line 37, which is insulated inside the pot.

The cylinder 2 has at its upper end in or on the jacket wall a permanent magnet 36, which can advantageously be an annular permanent magnet. Thus, through the coil 35 inside the pot and and the permanent magnet 36 on the cylinder formed an electrical transmitter system. The remaining parts of the telescopic shock absorber correspond to those in FIG. 1 to which reference is made.

If the pot 34 now moves relative to the cylinder 2, then due to this movement induces a voltage within the coil 35, which is transmitted via the lead 37 can be given in an electronic evaluation (not shown). Likewise A control signal derived from this evaluation can be fed to feed 32 and thus on the spool 20 within the piston rod 13 to change the position of the control spool.

Figure 4 shows an embodiment of a telescopic shock absorber according to the invention, wherein a coil 38 is arranged in the pot in the region of its bottom, which only consists of a single turn. The cylinder carries inside at its upper end of the pot a permanent magnet 39, which is also here preferably a ring magnet. The rest of the design of the telescopic shock absorber corresponds to that in Figure 1, which is why this is referred to.

If the cylinder moves so far into the pot that the limit indicator, formed by the system coil 38 - permanent magnet 39, emits a signal so becomes the telescopic shock absorber controlled harder.

Figure 5 shows a further embodiment of an inventive Telescopic shock absorber, whereby here additionally a directional discrimination of the movement the shock absorber takes place.

Inside the pot is z. B. a bifilar wound double coil 41 arranged. This double coil 41 has two outward feed lines 44 and 45 for their two winding layers. The cylinder carries on its upper end two permanent magnets 42, 43, which are preferably designed as ring magnets.

These two permanent magnets 42, 43 point with respect to their distance from each other z. B. a division by 1.5 times the winding distance of the double coil 41 so that the two signals received from the double coil 41 have a phase shift of 900. In this way, in addition to the other data such as speed, Acceleration, frequency also the direction of movement can be discriminated. With the reference number 46 is the ground connection of the telescopic shock absorber. Otherwise, the telescopic shock absorber corresponds to the design according to FIG. 1 and 3, which is why reference is made to them.

List of reference symbols 1 shock absorber 2 cylinder 3 cylindrical pot 4,5 brackets 6 lower chamber half 7 upper chamber half 8 disc 9,10 valve bores 11, 12 valve springs 13 piston rod 14 end part of the piston rod 15 nut 16 washer 17 cylinder cover 18 ring seal 19 longitudinal bore inside the piston rod 20 Coil 21 Armature 22 Conical holding part 23 Control slide 24 Compression spring 25 Counter bracket the spring 26 end wall 27 longitudinal bore within the end of the control slide 28,29 Cross bores within the control slide 23 to the longitudinal bore 27 30 transverse bore inside the piston rod to the through hole 31 inside the piston rod 31 Through hole 32 electrical supply to the coil 20 33 ground connection 34 cylindrical Pot 35 coil 36 ring-shaped permanent magnet 37 feed to coil 35 38 Coil consisting of a single turn 39 permanent magnet 40 coil feed line 41 double coil 42, 43 permanent magnets 44, 45 feed lines of the double coil 41 46 Ground connection L e r s e i t e

Claims (7)

Patent claims adjustable shock absorber, especially for motor vehicles, consisting of a cylinder filled with a damping fluid, in the axial a slidably arranged, hollow piston rod is immersed in it, in which a control or control means is arranged and at its end one against the cylinder wall carries sealed disc that divides the cylinder space into two chamber halves and the directional high and low pressure valves for connection of the two chamber halves for the damping fluid after overcoming the closing force of the valves, characterized in that in the upper part of the piston rod (13) a Coil (20) is arranged, within which an armature (21) is movably arranged, the axially at its end (14) facing the cylinder (2) has a control means forming control slide (23), which is located within the axial longitudinal bore (19, 31) of the piston rod is slidably arranged and that in the lower chamber half (16) the opening of this longitudinal bore closes, the longitudinal bore in the Area of the upper chamber half (7) is penetrated by a transverse bore (30) which is closed by the control slide in the rest position / working position or the other way around. 2. Adjustable shock absorber according to claim 1, characterized in that that the longitudinal bore (19) within the piston rod (13) is a blind bore, wherein within the end wall (26) of the piston rod an axial through bore (31) arranged centrally with a smaller diameter than the diameter of the longitudinal bore is through which through-hole the transverse bore (30) is guided and that the Control slide (23) dips with its lower end into the through hole and is spring loaded. 3. Adjustable shock absorber according to claim 2, characterized in that that the lower end of the control slide (23) has a longitudinal bore (27) which in the area of the longitudinal bore (19) of the piston rod (13) by a transverse bore (28, 29) is penetrated, so that the longitudinal bore of the piston rod and the interior of the Coil (20) are filled with damping fluid. 4. Adjustable shock absorber according to claim 1, characterized in that that the coil (20) has an electrical feed line (32) from outside the shock absorber (1). 5. Adjustable telescopic shock absorber with a cross-cylinder cylindrical pot, which carries the piston rod centrally on the inside according to claim 1, characterized in that the cylinder (2) at its upper end at or in the Outer wall has at least one permanent magnet (36) and that on the cylindrical Inside wall of the pot (34) arranged in the axial direction at least one coil (35) which has a supply line (37) to the outside. 6. Adjustable telescopic shock absorber according to claim 5, characterized in that that the permanent magnet is at least one ring magnet (36) on or in the 11 portion of the cylinder (2) is arranged. 7. Adjustable telescopic shock absorber according to claim 5, characterized in that that the cylinder <2) at its upper end two on or in the outer wall arranged permanent magnets (42, 43) which are mutually offset to a Direction-dependent, to generate electrical signal phase-shifted by 90 ° and that on the cylindrical inner wall of the pot (34) in the axial direction two coils (41) are arranged, each having a supply line (44, 45) to the outside.