EP0558714A1 - Systeme de suspension pour vehicules - Google Patents

Systeme de suspension pour vehicules

Info

Publication number
EP0558714A1
EP0558714A1 EP92918893A EP92918893A EP0558714A1 EP 0558714 A1 EP0558714 A1 EP 0558714A1 EP 92918893 A EP92918893 A EP 92918893A EP 92918893 A EP92918893 A EP 92918893A EP 0558714 A1 EP0558714 A1 EP 0558714A1
Authority
EP
European Patent Office
Prior art keywords
suspension system
pressure
actuator
storage
working
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP92918893A
Other languages
German (de)
English (en)
Inventor
Martin Scheffel
Rainer Heinsohn
Klaus Landesfeind
Martin Laichinger
Peter HÖLLERER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0558714A1 publication Critical patent/EP0558714A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/06—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using both gas and liquid
    • F16F9/063—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using both gas and liquid comprising a hollow piston rod
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
    • B60G17/02—Spring characteristics, e.g. mechanical springs and mechanical adjusting means
    • B60G17/04—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
    • B60G17/02—Spring characteristics, e.g. mechanical springs and mechanical adjusting means
    • B60G17/04—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics
    • B60G17/0416—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics regulated by varying the resiliency of hydropneumatic suspensions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
    • B60G2202/10—Type of spring
    • B60G2202/12—Wound spring
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
    • B60G2202/10—Type of spring
    • B60G2202/15—Fluid spring
    • B60G2202/154—Fluid spring with an accumulator
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/50—Pressure
    • B60G2400/51—Pressure in suspension unit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2500/00—Indexing codes relating to the regulated action or device
    • B60G2500/20—Spring action or springs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2500/00—Indexing codes relating to the regulated action or device
    • B60G2500/20—Spring action or springs
    • B60G2500/22—Spring constant

Definitions

  • the invention relates to a suspension system for vehicles according to the preamble of claim 1 or 2 and a method for operating this suspension system according to the preamble of claim 29 or 30.
  • an actuator is installed between a vehicle body and a wheel carrier.
  • the level of the vehicle body can be adjusted.
  • the aim is to keep the distance between the vehicle body and the wheel carriers constant, regardless of changes in load.
  • the force acting on the actuator can fluctuate considerably, e.g. by changing the payload, when cornering and when accelerating or braking.
  • the pressure of a pressure medium fed by the pressure source acts in a working space of the actuator. So that the actuator can also take over the task of vehicle suspension, the work area must be connected to a memory. It is therefore known to connect the working space of the actuator to a memory.
  • the store is a container in which the pressure medium can be pressurized by a gas.
  • the pressure in the accumulator apart from rapid changes in load, is the same as in the actuator's working space.
  • the pressure in the working space of the actuator can fluctuate considerably between very high and very low values. In the previously known suspension system, this causes considerable problems in the design of the accumulator, in the dimensioning of the pressure source and in a valve which controls the pressure in the working space of the actuator.
  • the accumulator is designed in such a way that it produces an acceptable accumulator characteristic at higher working pressures, the course of the accumulator characteristic curve in the range of small working pressures is very unsatisfactory in the previously known suspension system, because if the preload pressure is selected relatively high, then the Actuator does not work properly at working pressures below the preload pressure.
  • the preload pressure of the accumulator is chosen to be sufficiently low, then a very large accumulator must be used so that an acceptable accumulator characteristic results in the area of high working pressures, because if the size of the accumulator is too small, the suspension becomes too high in the area of high working pressures hard.
  • suspension system designed according to the invention with the characterizing features of claim 1 has the advantage that its suspension characteristics can be easily adapted to the respective requirements.
  • the suspension system designed according to the invention with the characterizing features of claim 2 has the advantage that even in the range of low working pressures to change the working pressure only a small amount of pressure medium has to flow into the storage system or out of the storage system.
  • the suspension system can work in the desired manner with components which are technically feasible in a vehicle.
  • the storage system can advantageously be connected directly to the working space of the actuator, in particular when a so-called X-cylinder is used as the actuator.
  • the direct connection of the storage system to the working space of the actuator also has the particular advantage that a clear, positive overlap can be provided in the neutral position of the control valve. Nevertheless, because of the direct connection of the storage system to the working space of the actuator that has become possible, one advantageously does not have to reckon with hard pressure surges from the actuator.
  • the hydraulic power required is significantly lower than with previously known suspension systems. Even with low hydraulic power, the suspension system according to the invention offers the possibility of very rapid level regulation. Compression or rebound can also be compensated for in the region of small support forces, advantageously with the supply or removal of even small amounts of pressure medium.
  • the suspension system has the advantage that almost any desired suspension comfort can be realized for each load value.
  • the suspension system can advantageously be manufactured in such a way that the pressure in the storage system does not collapse even when an extremely small supporting force occurs.
  • the characteristic of the memory system can advantageously be designed for a pressure down to zero.
  • the characteristic curve of the storage system can advantageously be optimized according to various criteria, as required. These criteria can e.g. be: Low average volume flow, low maximum volume flow, small average and / or small maximum power requirement of the hydraulic system with high suspension comfort at the same time.
  • control valve with a clear positive overlap between the switch positions gives a further energy saving effect, in particular also due to a low leakage oil loss.
  • FIGS. 1 to 9 and 11 to 15 each show an exemplary embodiment and FIG. 10 shows various characteristic curves by way of example. Description of the embodiments
  • the suspension system according to the invention can be used in any vehicle in which an actuator is installed between the vehicle body and the wheel carrier.
  • the wheel carrier is usually a left side or a right side of a vehicle axle.
  • a wheel is rotatably mounted on the wheel carrier or on each side of the vehicle axle.
  • actuators as there are wheels are used for each vehicle.
  • the first actuator 1 shows a first actuator 1 and a second actuator 2.
  • the first actuator 1 is installed approximately on the left front vehicle side between the vehicle body and the left side of the front vehicle axle, and the second actuator 2 is located at the front right between the vehicle body and the front vehicle axle.
  • the actuator 1 has a cylinder 4.
  • An actuator piston 6 is mounted displaceably within the cylinder 4.
  • the actuator piston 6 is attached to a piston rod 8.
  • the piston rod 8 protrudes from the cylinder 4 on one end face of the cylinder 4.
  • the other end of the cylinder 4 is connected to the vehicle body (not shown) or to the wheel carrier (not shown). Accordingly, the end of the piston rod 8 protruding from the cylinder 4 is connected to the wheel carrier or to the vehicle body.
  • FIG. 1 shows a storage system 10, a second storage system 12, a storage container 14, a pump 16, a central storage 18, a control valve 20, a second control valve 22, a switching valve 24, a second switching valve 26 and a valve 28
  • the pressure medium is, for example, a liquid, such as a hydraulic liquid.
  • the pump 16 sucks the pressure medium from the storage container 14 and presses it into a central supply line 30.
  • the central supply line 30 is connected to the central store 18.
  • a branch leads via a check valve 32 into an inlet line 34.
  • the inlet line 34 leads to an inlet connection 36 of the control valve 20 and to an inlet connection of the second control valve 22.
  • a return connection 38 of the control valve 20 and a return connection of the second control valve 22 are connected to the reservoir 14 via a return line 40.
  • An intermediate line 42 leads from a consumer connection 44 of the control valve 20 to the switching valve 24 and another intermediate line leads from a consumer connection of the second control valve 22 to the second switching valve 26.
  • a line 46 leads from the switching valve 24 to a working space 50 of the actuator 1
  • Another line connects the second switching valve 26 to a working space of the second actuator 2.
  • the storage system 10 is connected to the work space 50 via the line 46.
  • the storage system 10 can also be connected directly to the work space 50 of the actuator 1.
  • the second storage system 12 is connected to the working space of the actuator 2.
  • the working space 50 is located inside the cylinder 4 of the actuator 1 on the side of the actuator facing away from the piston rod 8. gate piston 6.
  • a pressure chamber 52 is formed on the other side of the actuator piston 6, a pressure chamber 52 is formed.
  • the pressure chamber 52 is connected to the working chamber 50 via a passage 54.
  • a control throttle 56 In the course of the passage 54 there is a control throttle 56.
  • the control throttle 56 can be opened more or less and, if necessary, it can also be completely closed.
  • the passage 54 can be provided in the actuator piston 6 or can be, for example, a line running outside the cylinder 4.
  • Another branch leads from the central supply line 30 to further control valves, not shown, with the aid of which further actuators, not shown, can be actuated.
  • the structure of the further control valves (not shown) and the other actuators (not shown) corresponds, for example, to the control valve 20 or the actuator 1.
  • the actuators 1, 2 belong e.g. to a vehicle axle and the other actuators, not shown, belong to another vehicle axle.
  • the pump 16 is, for example, a pressure-controlled pump. Instead, however, a constant pump can also be used and the pressure can be set with the aid of a pressure limiting valve.
  • the pressure control of the pump 16 can also be combined with a current control of the pump 16.
  • a filter 61 and a check valve 62 are located between the pump 16 and the central supply line 30.
  • the check valve 62 can be provided in order to prevent the central store 18 from being emptied if the pump 16 fails.
  • the check valve 32 prevents a pressure peak from possibly breaking through from the actuator 1 via the control valve 20 into the central supply line 30.
  • a further line leads from the central supply line 30 into the storage container 14. In the course of this further line there is a further valve 64.
  • the further valve is, for example, a seat valve which is open in the currentless state. In normal operation, valve 64 is energized and therefore closed. In the event of a fault, for example in the event of a lack of oil, the valve 64 is disconnected from the power supply and the pump can deliver pressure to the reservoir 14 via the valve 64.
  • the control valve 20 has a switching position 71, a switching position 72 and a switching position 73.
  • the switching position 72 the inlet connection 36, the return connection 38 and the consumer connection 44 are blocked against one another.
  • the switching position 71 the inlet connection 36 is connected to the consumer connection 44, and the return connection 38 is blocked.
  • the switching position 73 the inlet connection 36 is blocked and the consumer connection 44 is connected to the return connection 38.
  • the switch position 72 is located between the two switch positions 71 and 73. Depending on the embodiment, there is a stepless transition between the switch positions 71, 72, 73.
  • the control valve 20 can be brought into the switch position 71 or into the switch position 73 with the aid of, for example, two electromagnets, depending on the activation of the respective magnet. With the help of springs, the ' control valve 20 reaches the switch position 72 when the electromagnet is not actuated.
  • the control valve 20 is, for example, a proportional valve.
  • the switching valves 24, 26 each have three connections and two switching positions.
  • the third connection of the switching valve 24 is connected to the third connection of the switching valve 26 via a line 76 shown in broken lines.
  • line 76 In the course of line 76 there is a first choke 77 and a second choke 78.
  • the switching valve 24 is pressure controlled. This is symbolically represented in the drawing by a control line 80, shown in dashed lines and connecting the valve 24 to the inlet line 34, in dashed lines. Depending on the pressure in the inlet line 34, the switching valve 24 is in a first switching position 81 or in a second switching position 82. In the first switching position 81, the intermediate line 42 is connected to line 46 and the third connection to line 76 is blocked . In the second switching position 82 of the switching valve 24, the connection to the intermediate line 42 is blocked and the line 46 is connected to the line 76. When depressurized, i.e. if the pressure in the feed line 34 falls below a limit value, then the switching valve 24 switches to the second switching position 82. In the normal operating state, i.e. if the pressure in the feed line 34 is greater than the limit pressure, then the switching valve 24 is in the first switching position 81.
  • the working space 50 of the actuator 1 is connected to the working space of the actuator 2 via the line 76. This ensures that in the event of a malfunction between the working spaces 50 of the actuators 1, 2 there is no impermissibly large pressure difference over a long period of time.
  • the throttles 77, 78 are provided so that the pressure compensation does not take place too abruptly.
  • the valve 28 is, for example, a seat valve. In the normal operating state, the valve 28 is without current and the connection 79 from the line 76 into the return line 40 via the valve, 28 is not broken. If the pressure in the working space 50 of the actuator 1 and / or the pressure in the working space of the actuator 2 is too high as a result of some malfunction, the valve 28 can be energized and the pressure in the working spaces can be reduced. In this way, even in the event of a malfunction, the vehicle body can be prevented from rising to an excessively high level or from remaining at an excessively high level.
  • a large flow of pressure medium does not have to flow through line 76, connection 79 and control line 80.
  • the cross sections of 76, 79, 80 can therefore be dimensioned small, which is why these lines are shown in dashed lines in the drawings.
  • the pressure in the working space 50 of the actuator 1 can be detected with the aid of a sensor 88.
  • a sensor 89 detects the pressure in the working space of the second actuator 2.
  • the sensors 88, 89 deliver measured values to an electronics 90.
  • the electronics 90 can control the control valves 20, 22. If the pressure in the work space 50 is to be reduced or the level of the vehicle body is to be lowered, the electronics 90 switches the control valve 20 into the switching position 73. When the pressure in the work space 50 is increased or the pressure is increased Levels, the control valve 20 is actuated with the aid of the electronics 90 in the direction of the first switching position 71.
  • the actuator 1 of the suspension system has a multiple function: because of the connection of the working space 50 with the storage system 10, the actuator 1 can take over the task of vehicle suspension. Secondly, depending on the control of the control valve 20, the level of the vehicle body can also be raised or lowered. Thirdly, the actuator 1 can also serve as a shock absorber. The shock absorber function of the actuator 1 arises because of the control throttle 56 between the working chamber 50 and the pressure chamber 52. If the actuator 1 is to be strongly damped, the electronics 90 can, for example, actuate the control throttle 56 in the closing direction and, if the damping is desired, is low the control throttle 56 more open.
  • the control throttle 56 can be, for example, a throttle whose free flow cross section can be changed.
  • the control throttle 56 can, however, also be a type of pressure limiting valve, the control throttle 56 setting a more or less large pressure difference between the working space 50 and the pressure space 52 depending on the control.
  • the control throttle 56 can be a single element which is responsible for both flow directions.
  • the control throttle 56 can also consist of several individual valves, with some of these individual valves being responsible for one direction of flow and another part of the individual valves being responsible for the opposite direction of flow.
  • the memory system 10 comprises a memory 91, a memory 92 and a memory 93.
  • a memory 91 there is a variable memory space 101; there is a variable memory space 102 within the memory 92;
  • a variable storage space 103 is located inside the storage 93.
  • the variable storage spaces 101, 102, 103 contain a gas under pressure.
  • the gas of the different storage spaces 101, 102, 103 can be of the same or different type or composition.
  • a throttle 106 can also be provided between the working space 50 and the storage system 10.
  • a throttle 107 can also be arranged.
  • the throttle 107 is arranged in such a way that not all of the pressure medium exchanged with the storage system 10 is throttled, but only that which flows into or out of a part of the storage spaces 101, 102, 103.
  • the throttles 106, 107 can be constructed and modified in the same way as the control throttles 56.
  • the shock throttle function of the actuator 1 can be controlled to a sufficient extent with the control throttle 56. Therefore, the chokes 106, 107 are dispensable, at least in the embodiment shown in FIG. 1, which is why these chokes 106, 107 are shown in dashed lines.
  • the stores 91, 92, 93 shown in FIG. 1 are membrane stores. Piston accumulators can also be used instead, as shown in FIG. The mode of operation of the storage system 10 will first be explained in more detail with reference to FIG. 2.
  • Figure 2 shows another advantageous embodiment of the suspension system.
  • the memory system 10 comprises only two variable memory spaces 101, 102 in order to make the explanation of the mode of operation as simple as possible.
  • the variable storage spaces 101, _L02 As shown in FIG. 1, a further variable storage space or a plurality of variable storage spaces are added.
  • the storage system 10 comprises the variable storage space 101 and the variable storage space 102.
  • the gas in the variable storage space 101 is biased with a preload pressure pvl; the gas in the variable storage space 102 is prestressed with a prestressing pressure pv2.
  • the working pressure of the pressure medium in the working space 50 of the actuator 1 is referred to below as working pressure p50.
  • the gas of the reservoir 101 is separated from the pressure medium of the line 46 by means of a piston 111.
  • a piston 112 separates the gas in the variable accumulator 102 from the pressure medium in the line 46.
  • the pressure on the side of the storage system 10 which is acted upon by the pressure medium, ie on the side of the storage system 10 which is acted upon by liquid, apart from very rapid load changes of the actuator 1, is virtually the same as the working pressure p50 in the working space 50.
  • the simplicity For the sake of convenience, it is assumed in the following explanations that the pressure medium pressure acting on the storage system 10 is the same as the working pressure p50.
  • the illustration of the storage system 10 in FIG. 2 is selected such that the extension of the piston 111 described below corresponds in the drawing to a downward movement, and retracting means an upward movement. The same applies to the other pistons 112 and 113 and to the following figures.
  • the prestressing pressure pv2 of the gas in the variable storage space 102 is substantially greater than the prestressing pressure pvl of the gas in the variable storage space 101.
  • the prestressing pressure pv2 is selected such that the piston 112 remains in the fully extended state in the range of low working pressures p50, ie the working pressure p50 in the working space 50 is less than the preload pressure pv2 of the variable storage space 102.
  • the preload pressure pvl of the variable storage space 101 is selected such that the pressure medium actuates the piston 111 in the direction of the variable storage space 101 even in the range of low working pressures p50 can.
  • the working pressure p50 is greater than the preload pressure pvl of the variable storage space 101.
  • the working pressure p50 is greater than the preload pressure pv2 of the variable storage space 102. This has the consequence that only the variable storage space 101 is effective in the area of small working pressures p50, but in the area of larger working pressures p50, the variable storage space 102 is also an elastic element come in addition.
  • variable storage space 102 is switched on and off as required without using any valve.
  • variable storage space 101 works with the preload pressure pvl. Therefore, in order to achieve a pressure change in the work space 50, only one needs to be relative small amount of pressure medium can be conveyed into and out of the memory 91.
  • the use of a relatively small control valve 20, a small pump 16 and a small central store 18 is sufficient for this.
  • variable storage space 101 and the variable storage space 102 work together. Therefore, a flat spring characteristic can also be achieved in the range of relatively high working pressures ⁇ 50.
  • the pressure pv2 in the variable storage space 102 can be set relatively high, so that even with large working pressures p50, the remaining volume of the variable storage space 102 compressed by the working pressure p50 is large, so that even with relatively small stores 101, 102 also receives a flat spring characteristic in the range of high working pressures p50.
  • variable storage space 101 would have to be preloaded with a relatively small preload pressure, and a very large variable storage space would have to be provided, so that even in the area of large working pressures a sufficiently soft spring action can be achieved.
  • This single variable storage space would have to be substantially larger than the sum of the variable storage space 101 plus the variable storage space 102, since, due to the necessarily small preload pressure in the single variable storage space, it would be compressed to a very small remaining volume at high working pressures p50 .
  • the pressure medium volume flowing into the storage system 10 or out of the storage system 10 is relatively small for a desired change in the working pressure p50: firstly because the sum of the two variable storage spaces 101, 102 is also small is smaller than if only a single variable storage space were used, and secondly because in the range of low working pressures p50 only the memory 91 with the variable memory room 101 works.
  • two storage spaces 101, 102 preloaded with different preloading pressures pvl, pv2 considerable advantages can be achieved. These advantages can be further improved if one or more further variable storage spaces are provided in parallel with the variable storage spaces 101, 102.
  • Figure 3 shows a further advantageous embodiment.
  • variable storage space 101 and the variable storage space 102 are located within a common housing 115.
  • further variable storage spaces 103, 104 are provided.
  • the piston 111 is acted upon on one end face by the pressure medium and on the other end face by the gas of the variable storage space 101.
  • the piston 112 is acted upon on the one hand by the gas present in the storage space 101 and on the other hand by the gas of the variable storage space 102.
  • the variable storage space 101 is the space between the two pistons 111 and 112.
  • the preload pressure pvl of the variable storage space 101 is lower than the preload pressure pv2 of the variable storage space 102.
  • the piston 111 moves and the piston 112 remains in the extended state at a stop 116
  • the piston 111 has been retracted so far and the gas in the variable storage space 101 has been compressed so far, ie the pressure has risen so far that the gas in the variable storage space 101 has the piston 112 in can actuate in the driving direction, which is why the variable storage space 102 also works only in the range of larger working pressures p50.
  • the gas located in the variable storage space 102 leaks into the variable storage space 101.
  • the slight decrease in the gas in the variable storage space 102 leads to a small increase in the gas in the storage space 101, so that particularly small, at most insignificant changes are recognizable in the long term.
  • the preload pressure ⁇ v3 can be selected to be smaller or larger than the preload pressure pvl or pv2. It is also particularly expedient to select the preload pressure pv4 of the variable storage space 104 differently from the other preload pressures pvl, ⁇ v2, pv3.
  • the housing 115 can be provided with a cylinder bore, it being possible to choose the same diameter for the two pistons 111, 112.
  • the extension stroke of the piston 112 is limited with the aid of the stop 116 within the cylinder bore.
  • the cylinder bore serves as a sliding guide for the pistons 111, 112.
  • FIG. 4 shows a further, particularly advantageous embodiment.
  • the arrangement of the variable storage spaces 101, 102 shown in FIG. 4 largely corresponds to the arrangement of the variable storage spaces 101, 102 shown in FIG. 3.
  • the two pistons 111, 112 are arranged axially displaceably within the common sliding guide 122.
  • the piston 112 is connected to a bolt 124 provided with a thickened portion.
  • the thickening of the bolt 124 can come to rest against a stop 126 provided on the housing 115.
  • the extension stroke of the piston 112 can thus be limited. That is, the second piston 112 can only move within a partial area of the slide guide 122.
  • the first piston 111 can be actuated over almost the entire length of the sliding guide 122.
  • the piston 111 can also use almost the entire sliding guide 122 because: With increasing working pressure p50, the two pistons 111, 112 initially move in the retracting direction, whereby initially only the variable memory space 102 is reduced, but the variable memory space 101 remains constant. As soon as the bias pressure pvl of the variable storage space 101 is exceeded by the working pressure p50, the variable storage space 101 is also compressed.
  • At least a portion of the sliding guide 122 can thus be used jointly by both pistons 111, 112.
  • FIG. 5 shows a further, particularly advantageous embodiment of the suspension system.
  • two variable storage spaces are arranged within one housing.
  • the reservoir shown on the right in FIG. 5 with the two variable storage spaces 101, 102 largely corresponds to the embodiment shown in FIG. 4 with the difference that in FIG. 4 the extension movement of the piston 112 is carried out with the aid of a bolt 124 provided with a thickened portion is reached, whereas in the accumulator shown on the right in FIG. 5 the extension movement of the upper piston 112 can be limited by means of a bellows 128.
  • the two stores with the variable storage spaces 101, 102, 103, 104 largely correspond to one another with the difference that in the storage with the variable storage spaces 103, 104, instead of the gas-permeable bellows 128, a gas-tight membrane bellows 130 is used.
  • the diaphragm bellows 130 encloses a variable storage space 104 containing a gas. This gas is prestressed with a prestressing pressure pv4.
  • the storage space 104 is arranged within the storage space 103.
  • the piston 113 first moves in the retraction direction with increasing working pressure ⁇ 50. As soon as the working pressure p50 exceeds the preload pressure pv4, the underside of the diaphragm bellows 130 likewise moves in the direction of retraction, thus creating free space for the further retraction movement of the piston 113.
  • FIG. 6 shows a further advantageous exemplary embodiment. As can be seen from FIG. 6, not only can the prestressing pressures of the variable storage spaces be different, but also the diameters of the variable storage spaces can be of different sizes as required.
  • FIG. 6 largely corresponds to the embodiment shown in FIG. 4 with the difference that the additional variable storage space 103 is additionally provided in FIG. 6, the variable storage space 103 with the piston 113 having a larger diameter than the other two Storage spaces 101, 102.
  • FIG. 1 A further advantageous exemplary embodiment is shown in FIG.
  • FIG. 7 shows an exemplary embodiment in which, in the idle state, the volume of the variable storage space 101 closest to the working pressure p50 is larger than the volume of the variable storage space 102 and this is again larger than the volume most distant from the working pressure p50 of the variable dining room 103.
  • the preload pressure pvl of the storage space 101 is, for example, less than the preload pressure pv2 of the storage space 102 and this in turn is less than the preload pressure pv3 of the variable storage space 103.
  • FIG. 10 A further advantageous exemplary embodiment can be seen in FIG.
  • the storage system 10 is arranged outside the actuator 1.
  • the • storage system 10 is partially disposed within the actuator 1 and partially outside of the actuator 1 in the example shown in Figure 8 embodiment.
  • the piston 111 for separating the gas located in the variable storage space 101 from the pressure medium in the working space 50 is located within the cylinder 4.
  • the storage 92 which also belongs to the storage system 10, is arranged outside the actuator 1.
  • the memory with the variable memory space 101 and the memory 92 are acted upon by the working pressure p50 prevailing in the working space 50.
  • variable storage space 101 is arranged within the cylinder 4 in the axial direction as a continuation to the working space 50. However, it is just as possible to arrange a further cylinder outside the cylinder 4, which surrounds the cylinder 4, so that there is a space between the further cylinder and the cylinder 4, this space being able to be partially filled with a gas . If this intermediate space is connected to the working space 50 on its underside, then this intermediate space can serve as a variable storage space 101.
  • the production of this embodiment variant is easily possible for the person skilled in the art, so that an illustration of this embodiment variant can be dispensed with.
  • FIG. 9 shows another advantageous embodiment of the suspension system according to the invention.
  • the storage system 10 comprises the variable storage space 101, the gas provided in this space 101 being biased with the preload pressure pvl.
  • the piston 111 separates the gas from the variable storage space 101 from the pressure medium with which the actuator 1 is actuated.
  • an elastically deformable storage element 131 is additionally provided.
  • the elastically deformable storage element 131 is, for example, a helically wound steel spring, a group of steel springs or the like.
  • the gas of the variable storage space 101 acts on the piston 111 in the extension direction.
  • the elastically deformable storage element 131 acts on the piston 111 in the retracting direction. In other words, in this exemplary embodiment, the effect of the elastically deformable storage element 131 is counter to that of the variable storage space 101.
  • the line drawn in FIG. 10 and provided with the reference numeral 140 is an exemplary characteristic curve for the memory system 10 shown by way of example in FIG. 9.
  • This characteristic curve 140 is to be compared below with previously known memory systems.
  • the smallest working pressure p50 occurring in the working space 50 is, for example, 18 pressure units.
  • the characteristic of such a memory is shown in dashed lines in FIG. 10 and provided with the reference number 142. With such an accumulator, relatively small volumes are required for pressure changes even in the area of small working pressures, but in the area of a large working pressure p50, however, the storage characteristic becomes very steep and thus the suspension is very hard.
  • a storage system according to e.g. The exemplary embodiment shown in FIG. 9 with the characteristic curve 140 avoids the disadvantages mentioned here of the previously known storage systems.
  • a sufficiently flat characteristic curve of the storage system 10 is obtained, and in the area of small working pressures p50, the exchange of a small volume already results in a sufficient change in the working pressure p50.
  • the piston 111 is displaced upward in the region of high working pressures p50 and the elastically deformable storage element 131 is only relatively small or not biased at all. That is, the pressure of the gas in the variable storage space 101 is at most slightly higher than the working pressure p50 in the region of high working pressures p50. In the range of small working pressures p50, the elastically deformable storage element 131 is relatively strongly tensioned, so that the characteristic curve shown in FIG. 10 and provided with the reference number 140 is obtained.
  • the elastically deformable storage element 131 can be dimensioned such that it e.g. only with piston 111 extended relatively far, i.e. at low working pressures p50 works against the force of the pressure of the variable storage space 101, but lifts from the piston 111 in the region of high working pressures p50. Depending on the dimensions, the elastically deformable storage element 131 can also act on the piston 111 in the entire stroke range.
  • the elastically deformable storage element 131 can e.g. a steel spring with a linear characteristic. But you can also design the elastically deformable storage element 131 so that it has a progressive, a degressive or some other shaped force-displacement characteristic.
  • the actuator 1 springs relatively soft in the area of medium working pressures and springs relatively stiff in the area of very high working pressures and in the area of very low working pressures.
  • the elastically deformable storage element 131 only has to work against the effect of the variable storage space 101 in the range of small working pressures p50, so that the elastically deformable storage element 131 can be of relatively small dimensions in conventional applications.
  • the elastically deformable storage element 131 is a compression spring and outside of the variable storage space 101.
  • the elastically deformable storage element 131 can be used as a tension spring train and arrange within the storage space 101. The person skilled in the art can easily produce this, which is why an additional pictorial representation of this variant is dispensed with.
  • FIG. 11 shows another embodiment.
  • the memory system 10 comprises the memories 91, 92, 93.
  • the memory 91 there are the two variable memory spaces 101, 102, which are separated from one another by means of the displaceable piston 112.
  • the elastically deformable memory element 131 as well as an elastically deformable memory element 132 and an elastically deformable memory element 133 are also provided in the memory 91.
  • the elastically deformable storage elements 132, 133 are each one or more steel springs, for example.
  • the elastically deformable storage element 131 works, for example, in the embodiment shown in FIG. 11 in the same way as described with reference to FIG. 9.
  • the elastically deformable storage element 133 acts on the piston 112 in the extending direction and, roughly speaking, has a similar effect. like an increase in the preload pressure in the variable storage space 102. Therefore, for example, the memory 91 functions well if, for example, the preload pressure pvl in the storage space 101 is selected the same as the preload pressure pv2 of the variable storage space 102. This significantly simplifies the design of the piston 112, because in this case there is no concern about a leak between the two variable storage spaces 101, 102.
  • the elastically deformable storage element 132 can also be provided in the variable storage space 101, which only comes into effect from a certain retraction path of the piston 111 and thus influences the suspension properties of the actuator as required.
  • the storage elements 132, 133 can be of the same type as the storage element 131.
  • FIG. 12 shows a further embodiment of the suspension system.
  • the pressure of the pressure medium in the working space 50 is determined with the aid of the sensor 88.
  • the sensor 88 is a converter which converts the hydraulic pressure into electrical signals and control signals are generated with the aid of the electronics 90 and, depending on the pressure, among other things, the control valve 20 is brought into the desired position. That is, the control valve 20 can assume a position that depends, among other things, on the pressure in the working space 50.
  • the exemplary embodiment shown in FIG. 12 works in the same way. In this exemplary embodiment, too, the switching position of the control valve 20 depends, inter alia, on the pressure in the line 46, ie on the working pressure in the working space 50.
  • the pressure dependence of the switch positions of the Control valve 20 is indicated symbolically in FIG. 12 with the aid of the control line 148 shown in broken lines.
  • the control valve 20 can also be actuated electrically with the aid of the electronics 90, which is also indicated with the aid of an electrical line 150 shown in broken lines.
  • control signals for actuating the control valve 20 and the control throttle 56 can be combined as desired.
  • the control valve 20 is, for example, a proportional valve in which the different switching positions 71, 72, 73 can be set with the help of one or two proportional magnets acting in opposite directions.
  • two 2/2-proportional valves instead of just one valve, one of the two valves being responsible for releasing the path for the pressure medium from the supply line 34 in the direction of the actuator 1, in each case another valve is only responsible for releasing the flow direction from the actuator 1 in the direction of the return line 40. It is easy for a person skilled in the art to use two valve bodies for the respective different flow directions instead of just one valve body within the control valve 20, which is why this variant of the control valve 20 is not illustrated.
  • the switching valves 24, 26 may be omitted.
  • the consumer connection 44 of the control valve 20 is connected directly to the working space 50.
  • a membrane or a piston can be used to separate the gas from the pressure medium in each illustrated embodiment. In some cases it is also possible to apply the gas directly to the pressure medium, ie without a membrane or piston. In some cases, the pressurized gas of the storage system 10 can be replaced by one or more springs. However, a complete replacement is rarely possible considering the size and weight.
  • control valve 20 can be provided with a further consumer connection.
  • the control valve 20 is e.g. can also be produced in such a way that in the switching position 71 the pressure chamber 52 is additionally connected to the return line 40, and in the switching position 73 the pressure chamber 52 is additionally connected to the inlet line 34.
  • the person skilled in the art can easily produce this embodiment variant, which is why a figure showing this variant is dispensed with.
  • the suspension system can be adapted to any vehicle or driver request at any time with ease, e.g. by one or more of the preload pressures pvl, pv2, pv3 etc. changed so that the desired suspension characteristics are obtained.
  • suspension system means are specified by means of which each or at least every technically meaningful spring characteristic of the storage system 10 can be achieved. That the suspension system with the storage system 10 is constructed in such a way that any or at least almost any choice of the spring characteristic of the storage system 10 is possible. As a result, the suspension characteristics of the suspension system can be freely selected within wide limits.
  • the spring characteristic of the storage system 10 can be selected, for example, so that only a small volume of pressure medium is required to change the working pressure p50 even in the range of small working pressures.
  • the method can be designed in such a way that only a small volume of pressure medium is necessary in or in the range of small working pressures to change the working pressure p50.
  • the damping can be carried out solely or predominantly by the control throttle 56.
  • FIG. 13 shows a further advantageous exemplary embodiment.
  • the actuator 1 comprises the working space 50 and the pressure space 52. Such an actuator is often referred to as a separating cylinder.
  • the pressure chamber 52 is omitted for the actuator 1.
  • the actuator 1 shown in FIG. 13 is often referred to as a plunger cylinder.
  • the control throttle 56 is also omitted in FIG. 13.
  • the throttle 106 is provided in FIG. 13 so that the actuator 1 shown in FIG. 13 can also perform a shock absorber function. If the throttle 106 is designed to be changeable, the damping of the actuator 1 can also be changed.
  • the throttle 107 shown in dashed lines can also be provided.
  • the throttle 107 is arranged such that the damping is only effective with respect to a part of the storage spaces 101, 102, 103. With the throttle 107 it is thus possible that the damping caused by the throttle 107 is only effective, for example, above or below a certain working pressure p50. As already mentioned several times, p50 is the working pressure effective in the work space 50. If the biasing pressures in the variable feed spaces 102, 103 are greater than the biasing pressures in the variable storage space 101, the throttle 107 is only effective if the working pressure p50 exceeds the smallest of the biasing pressures of the two variable storage spaces 102, 103.
  • the volume of the pressure medium flowing out of the storage system 10 or into the storage system 10 is substantially more uniform, i.e. depends less on the prevailing working pressure p50, i.e. fluctuates less than in the previously known systems, there are also significantly fewer problems with the design of the throttle 106 or the throttle 107 compared to the previously known systems.
  • FIGS. 14 and 15 each show a further advantageous exemplary embodiment.
  • the described actuator 1, 2 usually has a piston rod 8 with a relatively large outside diameter. This relatively large outer diameter of the piston rod 8 is required in order to maintain the high supporting forces of the actuator 1, 2 while still being able to apply system pressure. In order to be able to make the suspension system as small as possible, it is proposed that at least one of the storage spaces 101, 102, 103, 104 be arranged within the piston rod 8.
  • the piston rod 8 is hollow and the piston 111 is mounted axially displaceably within the piston rod 8.
  • the piston 111 separates the pressure medium from a gas space which, in the embodiment shown in FIG. 14, is located below the piston 111.
  • the pressure medium is inside the piston rod 8 above the piston 111. From this space there is an opening 152 which connects this space to the work space 50.
  • the two accumulators 92, 93 and the accumulator 91 operate in parallel, depending on the prestressing pressures in the accumulators 91, 92, 93.
  • the opening 152 shown in FIG. 14 is omitted. Instead, there is an opening 154 in FIG. 15.
  • the opening 154 is located close to the actuator piston 6 and connects the pressure space 52 to the storage space 101 of the storage 91. This has the advantage over the exemplary embodiment shown in FIG. 14 that the pressure medium flowing to the memory 91 must first flow through the control throttle 56. The resulting pressure difference brings about a greater extension force of the piston rod 8 compared to the embodiment shown in FIG. 14.
  • the required supporting force of the actuator 1 with the control valve 20 or pump 16 of the same size is faster can be achieved, since the pressure p50 in the working space 50 can rise more quickly and the reservoir 91 is filled only with a delay, ie the reservoir 91 operates out of phase.
  • the cross section of the opening 152 can be dimensioned so narrow that this opening 152 can serve as a throttle, corresponding to the throttle 107 in FIG. 1.
  • Actuator 1, shown in FIG. 13 and constructed somewhat differently, can likewise arrange at least some of the accumulators 91, 92, 93 within the piston rod 8.
  • the filling of the accumulators 91, 92, 93 can be influenced by appropriately dimensioning the throttles 106, 107 or the openings 152, 154. With appropriate dimensioning, the filling or emptying of the accumulators 91, 92, 93 is somewhat delayed, so that the actuator 1 can be reacted quickly with a relatively small control valve 20 or small pump 16.
  • the volumes of the accumulators 91, 92, 93 can be of different sizes, and here too the accumulators 91, 92, 93 can have different clamping pressures.
  • some of the stores 91, 92, 93 are so-called piston stores and some are so-called membrane stores.
  • Piston accumulators basically have a so-called hysteresis loop in their characteristic, which is not exactly desirable.
  • the diaphragm accumulator is expediently provided with a lower preload pressure than the piston accumulator.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Vehicle Body Suspensions (AREA)

Abstract

Un système de suspension courant, présente le désavantage d'être très rigide lorsque les pressions de travail sont élevées et de nécessiter, lorsque les pressions de travail sont basses, le déplacement de très grands volumes de fluide sous pression. Dans le système de suspension présenté ici, il est prévu un système d'accumulation (10) permettant d'obtenir une variation de la pression de travail avec des volumes de fluides sous pression relativement petits également pour de petites pressions de travail. Ce système de suspension convient particulièrement aux véhicules automobiles.
EP92918893A 1991-09-21 1992-09-08 Systeme de suspension pour vehicules Withdrawn EP0558714A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE4131538 1991-09-21
DE4131538 1991-09-21
DE4226754 1992-08-13
DE4226754A DE4226754A1 (de) 1991-09-21 1992-08-13 Aufhaengungssystem fuer fahrzeuge

Publications (1)

Publication Number Publication Date
EP0558714A1 true EP0558714A1 (fr) 1993-09-08

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ID=25907584

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EP92918893A Withdrawn EP0558714A1 (fr) 1991-09-21 1992-09-08 Systeme de suspension pour vehicules

Country Status (5)

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EP (1) EP0558714A1 (fr)
JP (1) JPH06502824A (fr)
DE (1) DE4226754A1 (fr)
SK (1) SK50193A3 (fr)
WO (1) WO1993005971A1 (fr)

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WO1993005971A1 (fr) 1993-04-01
JPH06502824A (ja) 1994-03-31
SK50193A3 (en) 1993-08-11
DE4226754A1 (de) 1993-03-25

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