DE10143117C1 - Spring suspension system for heavy commercial vehicle has hydraulic springs for same wheels of each front axle coupled together via hydropneumatic spring system for uniform load distribution - Google Patents

Abstract

The spring suspension system has 2 front axles (1,2) provided with steered wheels (3), the same wheels of both front axles supported from the vehicle chassis (5) via hydraulic spring cylinders (4), which are coupled together via a hydropneumatic spring system (6). Each of the front axles is coupled to the chassis via pairs of longitudinal springs (7) and at least one transverse steering element (8). The spring cylinders are associated with regulating and blocking valves operated via an electronic control unit.

Description

The invention relates to a spring system for a truck or a bus with two Front axles according to the preamble of claim 1.

When driving over an obstacle, the structure of a vehicle becomes a vertical section acceleration exposed. The suspension of the vehicle has the task of this verti intercept calving accelerations.

DE 23 53 740 A1 discloses a leaf-sprung axle assembly of a vehicle, in which the leaf spring ends associated with each axle body each have a lever end an angle lever articulated to the vehicle frame are connected. This Angle levers are articulated at their other lever ends with a frame-fixed Hydraulic cylinder connected, which when necessary actuates the distance of the Axle body to the vehicle frame can vary, thereby possibly a load compensation between the two axles of the axle assembly or lifting the drive to effect. However, the amount of the variable level of the vehicle due to the limited size of the bell crank, there are narrow limits.

The invention has for its object a spring system for a truck or for an omnibus with two front axles to create a 100% axle load guaranteed between both front axles.

This object is achieved in that all wheels of the two before deraxes against the driver only via hydraulic oil-actuated hydraulic spring cylinders tool frame springs are supported and level-adjustable, the hydraulic Spring cylinder - to achieve a 100% axle load balance between the two Front axles - hydraulically communicating with one another, essentially Chen hydropneumatic spring system arranged on the vehicle frame are associated. because at each front axle is in each case arranged in pairs of trailing arms and at least a wishbone element connected to the vehicle frame. As a wishbone element a Panhard rod, a wishbone or the like can be provided.  

The solution according to the invention is thus a spring system for a truck or created for a bus with two front axles, which occurs when Bode occurs Now the road surface is unloaded, resulting in loads on both front axles distributed absolutely evenly on these and thus one-sided overloading of one of the two Front axles effectively prevented.

The way the spring system works causes two front wheels between the wheels Load balancing is carried out on the axles of one side of the vehicle. This balances the load achieved that the two hydraulic spring cylinders on one side of the vehicle by means of hydraulics line are interconnected and according to the principle of operation with a pressure medium ge filled U-tube works. As with such a U-tube, the spring according to the invention system with one spring movement of one of the two hydraulic spring cylinders on the tool side, the pressure medium is displaced from it and by a hydraulic connection cable pressed into the second hydraulic spring cylinder. When using a Incompressible pressure medium thus becomes a piston of the first hydraulic spring cylinder pushed out by exactly the same amount that the piston of the second hydraulic Spring cylinder of a vehicle side is pressed. According to this principle of action acts the same on both pistons of the two hydraulic spring cylinders on one side of the vehicle che force.

By using the spring system according to the invention there is an axle or wheel load compensation given, which both the problem of overloading the front axles at Überfah solves an obstacle as well as further improvements in the driving behavior of the vehicle results. So there is an almost 100% avoidance of a wheel load error between two front axles. Likewise, due to obstacles, unequal entry and exit Rebound paths on the front axles can be completely compensated, which with Ausfü conventional spring systems is not possible.

In addition, the spring system according to the invention offers, in addition to reducing the wheel load errors also the advantage of allowing large compensation paths for the front axles and at the same time only need a small installation space.

Furthermore, the hydropneumatic spring system has a load-dependent spring behavior on what a significantly improved driving behavior of the vehicle, especially in Allows the vehicle to run empty.  

By eliminating the otherwise usual parabolic springs and the use of trailing arms each front axle is an unwanted change in caster angle of the front axle Braking processes due to spring twisting otherwise occurring are eliminated. The one in this Driving situation of the vehicle occurring caster angle changes due to the dyna Mix axle load shift can advantageously be kept low.

Furthermore, the vehicle is kept at a constant level by means of the hydropneumatic spring system Ride level can be brought, whereby the otherwise occurring level differences between loaded and unloaded condition of the vehicle can be compensated.

According to a further embodiment of the invention, the hydropneumatic spring system one per vehicle side, arranged on the vehicle frame and with a hyd raulikkreislauf and a pneumatic circuit related pressure accumulator have cylinders, the primary space of each with a - the pneumatic suspension of the commercial vehicle causing - compressible pneumatic medium is filled and the This secondary room - acting as a compensation volume - each with an incompress siblen, supplying pressure to the hydraulic spring cylinders on one side of the vehicle Hydraulic medium is filled. A nitrogen gas and For example, a hydraulic oil can be provided as the hydraulic medium.

Due to the existing in the secondary space of the respective pressure cylinder equal volume of hydraulic medium can act on the vehicle frame Forces when crossing an obstacle are greatly reduced. Rather, one therefore, when driving over a hill quickly, the vehicle mass does not track extremely quickly accelerated above, because first the pressure medium in the secondary space of the Druckspeicherzy linders is pressed. The pneumatic medium is compressed, while the Hydraulic medium in the secondary space of the pressure storage cylinder is also continuous is compressed.

So the lifting movement of the vehicle when driving over an obstacle as well acceleration forces counteracting the lifting movement can be greatly reduced where is significantly reduced by the stress on the vehicle frame. Furthermore depending on the deflection of the two front axles of hydraulic medium in the pressure storage cylinder to the respective load state of the Adjust vehicle. A loaded vehicle has a higher spring rate than an unladen one  Vehicle on. The spring rate thus adapts to the load on the vehicle, thus also the bumps when driving over an obstacle according to the load of the vehicle can be cushioned. Because all hydraulic spring cylinders are the same are dimensioned, the same hydraulic pressure is applied to each of these spring cylinders, so that when the two front axles are deflected, the suspension forces on them are the same be distributed moderately.

According to a further embodiment of the invention, the primary space of the two can Accumulator cylinder from a common pneumatic accumulator with the pneumatic unit dium and each of the secondary space of the two pressure cylinders by one entire hydraulic accumulator can be supplied with hydraulic medium.

According to a further embodiment of the invention, cylinder spaces of the hydraulic Spring cylinder on one side of the vehicle - for the purpose of roll stabilization of the commercial vehicle - with cylinder spaces of the hydraulic spring cylinders on the other side of the vehicle crosswise hyd be connected This stabilizes the possible side tilt of the Vehicle significantly improved.

According to a further embodiment of the invention, each side of the vehicle can be the one current hydraulic circuit can be assigned hydraulically automatically controlling control valve, wel ches in the hydraulic circuit between the pressure cylinder and the associated Hydraulic spring cylinders is integrated.

Furthermore, it can be the control valve on one side of the vehicle, which is connected to the Re gel valve of the other side of the vehicle is hydraulically connected crosswise.

According to a further embodiment of the invention, for the purpose of blocking the spring Effect of the hydropneumatic spring system - one hydraulic on each side of the vehicle circuit between the hydraulic spring cylinder and the accumulator cylinder locking hydraulic cal blocking valve may be provided, with an egg between the hydraulic spring cylinders Hydraulic flow through the existing section of the hydraulic circuit on the vehicle side remains cash.  

According to a further embodiment of the invention, the hydraulic control valves and blocking valves can be connected to a common hydraulic control block or in a hydraulically self-regulating and, if necessary, electrically controllable function unit can be summarized, the hydraulic control block or the hydraulic radio tion unit for supplying the hydropneumatic spring system with hydraulic medium are connected to the hydraulic accumulator.

According to a further embodiment of the invention, they can be articulated on the vehicle frame-connected trailing arms additionally articulated with frame-mounted displacement sensors in Are connected which - for level control of the hydropneumatic spring system - the vertical pivoting movements of the trailing arms, which can be registered as a lifting movement Control signals directly or indirectly to the control block or the functional unit of the Pass on the hydropneumatic spring system.

According to a further embodiment of the invention, the one with the displacement sensors can also be used Telbar related control block / functional unit from an electronic control unit - for the purpose of leveling the vehicle if necessary - can be controlled.

By means of the electronic control unit, the electrically switchable valves of the control blocks or the functional unit for the functions (leveling, lifting, lowering and Blocking) of the hydropneumatic spring system. The load-dependent Damping and load-dependent roll stabilization of the hydropneumatic spring system can can be realized without electronics in purely hydraulic ways. Leveling is to be understood hen that with the help of the distance sensors the distance between the front axle and vehicle frame men is determined. If the distance does not correspond to the construction of the vehicle is it, the electronic control unit either pumps in or out Pen hydraulic fluid in / out of the accumulator cylinders until the desired construct position of the vehicle is reached.

According to a further embodiment of the invention, each hydraulic spring cylinder can also be used Means of a cylinder block to be attached to the vehicle frame, the cylinder blocks through a common cross member are interconnected. Can advantageously verse the cylinder blocks for the first and second front axles with the same hole pattern hen, whereby a possible variety of parts is reduced.  

According to a further embodiment of the invention, a cylinder block can be provided for each front axle of a hydraulic spring cylinder have an integrated Panhard rod connection on this the Panhard rod articulated on the front axle is articulated. In this way, further component components are advantageously avoided. To an over avoiding the load on the cylinder block that connects the Panhard rod in an articulated manner a cross member connecting the cylinder blocks of each front axle may be arranged. By connecting both cylinder blocks of a front axle through the cross member the forces introduced by the Panhard rod on one cylinder block on the opposite overlying cylinder block are at least partially redirected. Instead of a Panhard stabes can also support the respective front axle transversely to the direction of travel Wishbone elements such as wishbones or the like can be provided.

Furthermore, the elimination of the otherwise common parabolic springs makes it easier Execution of various holding elements, such as one articulated on the trailing arm Combination trestle (frontend) that supports the vehicle frame.

The invention is based on the exemplary embodiments shown in the drawing explained in more detail.

Show it:

Seen in perspective view obliquely from the front Fig. 1 is a Fahrzeugrah men of a truck with two steerable front axles,

Fig. 2 is a side view of a vehicle frame of a truck shown in FIG. 1 when driving over an obstacle,

Fig. 3 in a front view seen in the direction of the first front axle,

Fig. Fragmentary 4 and in side view a second embodiment of a vehicle frame arranged on the first front axle,

Fig. 5 and fragmentary side view of a second front axle of a lorry according to Fig. 1,

Fig. Fragmentary 6 and in plan view arranged at the second vehicle frame front according to Fig. 5,

Fig. 7 in front view of a first front axle of a truck according to FIGS. 1 and

Fig. 8 schematically shows a block diagram of essential components of the hydropneumatic spring system.

In Fig. 1, a body frame 5 is shown a truck with two steerable front axles 1, 2 in a perspective view as seen obliquely from the front. Alternatively, the two steerable front axles 1 , 2 can also be arranged on a vehicle frame (not shown here) of an omnibus.

Steerable wheels 3 are provided at the end of the front axles 1 , 2 , which are supported by hydraulic spring cylinders 4 against the vehicle frame 5 in a resilient and level-adjustable manner. The hydraulic spring cylinders 4 - for achieving a 100% axle load balance between the two front axles 1 , 2 - hydraulically communicating with each other, a common, essentially arranged on the vehicle frame 5 , hydraulic pneumatic spring system 6 ( Fig. 8). Furthermore, both front axles 1 , 2 are each firmly connected to trailing arms 7 and articulated to the vehicle frame 5 by means of these. In this embodiment variant, each front axle 1 , 2 is also connected to the vehicle frame 5 via a Panhard rod 8 . According to another embodiment variant, not shown here, each front axle 1 , 2 can be connected to the vehicle frame 5 via transverse links or the like connected to it.

The hydropneumatic spring system 6 ( FIG. 8) has a single pressure cylinder 11 arranged on the vehicle frame 5 and connected to a pneumatic circuit 9 and a hydraulic circuit 10 on each vehicle side.

In Fig. 2 is a side view of a vehicle frame 5 of FIG. 1 with two steerable front axles 1 , 2 of a truck when driving over an obstacle 30 is shown. Each of the two front axles 1 , 2 carries steerable wheels 3 which are supported by the hydraulic spring cylinder 4 against the vehicle frame 5 . The front axles 1 , 2 are connected to trailing arms 7 , which are each articulated at their other end to frame-fixed holders. The trailing arms 7 are guided in front of the front axles 1 , 2 in this embodiment, as seen in the direction of travel.

According to another embodiment shown in FIG. 4, the trailing arms 7 are located behind the respective front axle 1, as seen in the direction of travel.

The trailing arms 7 articulated to the vehicle frame 5 are additionally articulated to position sensors 23 ( FIGS. 2, 3, 4, 8) fixed to the frame. The displacement sensors 23 give the level control of the vehicle to the vehicle frame 5 as a lifting movement, if necessary to compensate for vertical pivoting movements of the trailing arm 7 via control signals, not shown here, to a common hydraulic function unit 29 or a hydraulic control block 16 ( FIG. 8) of the hydropneumatics -Spring system 6 further. The functional unit 29 or the control block 16 controls the individual hydraulic spring cylinders 4 of the two front axles 1 , 2 as required, depending on the measured values detected by the displacement sensors 23 , if necessary a level regulation of the vehicle. The hydraulic functional unit 29 is shown in dashed lines in FIG. 8 and contains various control valves 14 , blocking valves 15 and the hydraulic control block 16 as control elements of the hydropneumatic spring system 6 . This control link of the hydropneumatic spring system 6 can - as shown in Fig. 8 lined - realized as separate individual components, have a functional interrelation.

In Fig. 3, the first front axle 1 according to the vehicle in Fig. 1 is shown from the front. Since each hydraulic spring cylinder 4 is attached to the vehicle frame 5 by means of an associated cylinder block 19 , 20 . Both cylinder blocks 19 , 20 are connected to one another by a common cross member 21 which partially transmits the forces transmitted by the Panhard rod 8 to the cylinder block 20 to the opposite cylinder block 19 . The right cylinder block 20 seen in the direction of travel has an integrated Panhard rod connection 22 on the underside, to which the other end can be fastened in an articulated manner to the Panhard rod 8 arranged on the first th front axle 1 .

The cylinder blocks 19 , 20 are designed in such a way that they have a horizontal stop 24 on the underside, which, when the first front axle 1 is deflected, possibly corresponds to a buffer 25 which is arranged opposite the stop 25 arranged opposite the front axle 1 ( FIG. 7). The same applies to the second front axle 2, which is not shown here.

Furthermore, below the vehicle frame 5 is the displacement sensor 23 which is articulated to the trailing arm 7 and which is shown in FIG. 4 in a side view and in FIG. 8.

The side sensor 23 shown in FIG. 4 in side view and in block diagram in FIG. 8 corresponds in a manner not described here in more detail with the electrical control unit 26 shown in dashed lines in FIG. 8, which, if necessary, control-related to the valve position of the individual for the purpose of leveling the vehicle Control elements 14 , 15 , 16 of the hydraulic functional unit 29 have an influence.

As an alternative to this, it is possible for the displacement sensors 23 to directly or indirectly correspond to the hydraulic control block 16 and the hydraulic control elements (for example control valve 14 ) connected here for the purpose of leveling the vehicle.

In Fig. 5 is seen in the direction of travel, the second front axle 2 shown in FIG. 1 in Seitenan view. The second front axle 2 is held on the vehicle frame 5 by the trailing arm 7 , the cylinder block 20 and the hydraulic spring cylinder 4 . The pressure storage cylinder 11 provided for the right side of the vehicle when viewed in the direction of travel is advantageously arranged lying in the plane of the vehicle frame 5 . The same also applies to the pressure storage cylinder 11, not shown here, of the left side of the vehicle.

The vehicle frame 5 shown in FIG. 5 is shown in detail in FIG. 6. The right cylinder block 20 seen in the direction of travel has the Panhard rod connection 22 in its lower region for the respective receptacle of the Panhard rod 8 . The two cylinder blocks 19 , 20 are connected to each other in an area below the vehicle frame 5 by the common cross member 21 . Each side of the vehicle has the pressure storage cylinder 11 intended for it.

In FIG. 7, these pressure storage cylinders 11, which are arranged approximately in the plane of the vehicle frame 5, are shown on the basis of the front view of the first front axle 1 .

In Fig. 8, a block diagram of essential components of the hydropneumatic spring system 6 is shown schematically. This has on each vehicle side the individual, on the vehicle frame 5 arranged both with a pneumatic circuit 9 and a hydraulic circuit 10 in connection with the pressure storage cylinder 11 . The two Druckspei cher cylinder 11 each have a primary space 12 , each of which is filled with a - the pneumatic cushioning of the commercial vehicle - compressible pneumatics medium. This can be given, for example, by a nitrogen gas or the like. If necessary, the primary spaces 12 of the pressure storage cylinders 11 can be supplied with pneumatic medium 27 by a pneumatic storage 17 . Furthermore, the two pressure storage cylinders 11 each have a secondary space 13 , each of which is filled with an incompressible hydraulic medium 28 which pressurizes the hydraulic spring cylinders 4 of a vehicle side. This can be given, for example, by a hydraulic oil or the like. The secondary spaces 13 of the pressure storage cylinders 11 can, as shown in FIG. 8, be supplied with hydraulic medium indirectly via the hydraulic control block 16 or alternatively the hydraulic functional unit 29 (dashed line) and the hydraulic control valves 14 and the hydraulic blocking valve 15 .

According to another variant, not shown here, the secondary spaces 13 of the pressure storage cylinders 11 can optionally be supplied directly from the hydraulic accumulator 18 with hydraulic medium 28 .

To achieve roll stabilization of the commercial vehicle, cylinder spaces of the hydraulic lik spring cylinder 4 of the one vehicle side with cylinder spaces of the hydraulic Federzy cylinder 4 of the other side of the vehicle are hydraulically interconnected.

Each side of the vehicle 10 is a hydraulically associated with self-steering control valve 14 to the respective hydraulic circuit, which is integrated the hydraulic circuit 10 between the pressure storage cylinder 11 and the associated therewith hydraulic spring cylinders. 4 In this exemplary embodiment, the control valve 14 of the one vehicle side is hydraulically connected crosswise to the control valve 14 of the other vehicle side. As an alternative to this, the crosswise connection of both sides of the hydraulic circuit 10 can take place via other suitable hydraulic elements.

Optionally, in order to block the spring action of the hydropneumatic spring system 6 , a hydraulic blocking valve 15 blocking the hydraulic circuit 10 between the hydraulic spring cylinder 4 and the pressure storage cylinder 11 can be provided on each vehicle side. In this case, an existing between hydraulic spring cylinders 4 from a vehicle side From section of the hydraulic circuit 10 can be flowed through hydraulically, so that the axle load-compensating effect of the hydropneumatic spring system 6 is retained.

As shown in Fig. 8, there is the possibility of connecting the hydraulic control valves 14 and blocking valves 15 to a common hydraulic control block 16 . As an alternative to this, it is possible to combine the control valves 14 and blocking valves 15 together with the hydraulic control block 18 - as shown in broken lines - in a hydraulically self-regulating functional unit 29 . This can be regulated purely hydraulically and optionally optionally controlled by an electrical control unit 26 . By means of the control of the hydraulic control valves 14 , the blocking valves 15 and the common hydraulic control block 16 by the electrical control unit 26 , in addition to the axle load compensation of the two front axles 1 , 2, a leveling of the front axles 1 , 2 and thus the vehicle can be carried out if necessary ,

Claims (12)

1. Spring system for a truck or an omnibus with two front axles ( 1 , 2 ) whose steerable wheels ( 3 ) suspended at the ends thereof are supported against a vehicle frame ( 5 ) via spring elements, characterized in that

• a) all of the wheels ( 3 ) of the two front axles ( 1 , 2 ) are supported against the vehicle frame ( 5 ) by means of hydraulic spring cylinders ( 4 ) that can be actuated by pressure oil and are designed to be level-adjustable so that
• b) the hydraulic spring cylinders ( 4 ) hydraulically communicating with one another, essentially on the vehicle frame ( 5 ) arranged hydraulic pneumatic spring system ( 6 ) are associated, and that
• c) each front axle ( 1 , 2 ) is connected via paired trailing arms ( 7 ) and at least one wishbone element ( 8 ) to the vehicle frame ( 5 ).

2. Spring system according to claim 1, characterized in that the hydropneumatic spring system ( 6 ) per vehicle side a single, on the vehicle frame ( 5 ) angeord Neten and with a pneumatic circuit ( 9 ) and a hydraulic circuit ( 10 ) in connection with the pressure storage cylinder ( 11 ) having,

• a) whose primary space ( 12 ) is filled with a compressible Pneumatikme medium ( 27 ) and
• b) whose secondary space ( 13 ) is filled with an incompressible hydraulic spring cylinder ( 4 ) supplying hydraulic pressure ( 28 ) to one side of the vehicle.

3. Spring system according to claim 2, characterized in that in each case the primary space ( 12 ) of the two pressure accumulator cylinders ( 11 ) from a common pneumatic accumulator ( 17 ) with the pneumatic medium ( 27 ) and in each case the secondary space ( 13 ) of the two pressure accumulator cylinders ( 11 ) can be supplied with hydraulic medium ( 28 ) from a common hydraulic accumulator ( 18 ). 4. Spring system according to claim 3, characterized in that a nitrogen gas is used as the pneumatic medium ( 27 ) and a hydraulic oil is used as the hydraulic medium ( 28 ). 5. Spring system according to one of claims 1 and 2, characterized in that Zy cylinder spaces of the hydraulic spring cylinder ( 4 ) one side of the vehicle with Zylinderräu men the hydraulic spring cylinder ( 4 ) of the other side of the vehicle are cross-connected hydraulically. 6. Spring system according to one or more of the preceding claims 1 to 5, characterized in that each vehicle side is assigned a respective hydraulic circuit running ( 10 ) hydraulically automatically controlling control valve ( 14 ) which in the hydraulic circuit ( 10 ) between the pressure storage cylinder ( 11 ) and the hereby connected hydraulic spring cylinders ( 4 ) are integrated, and that the control valve ( 14 ) of one side of the vehicle is hydraulically connected crosswise to the control valve ( 14 ) of the other side of the vehicle. 7. Spring system according to one or more of the preceding claims 1 to 6, characterized in that a hydraulic circuit ( 10 ) between hydraulic spring cylinder ( 4 ) and pressure storage cylinder ( 11 ) blocking hyd raulische blocking valve ( 15 ) is provided on each side of the vehicle, wherein a between the hydraulic spring cylinders ( 4 ) one side of the vehicle existing section of the Hydraulikkreislau fes ( 10 ) remains flowable. 8. Spring system according to one or more of the preceding claims 1 to 7, characterized in that the hydraulic control valves ( 14 ) and blocking valves ( 15 ) can be connected to a common hydraulic control block ( 16 ) or in a hydraulically self-regulating and, if necessary, electrically controllable radio tion unit ( 29 ) can be summarized, the hydraulic control block ( 16 ) or the hydraulic functional unit ( 29 ) being connected to the hydraulic accumulator ( 18 ). 9. Spring system according to one or more of the preceding claims 1 to 8, characterized in that the articulated to the vehicle frame ( 5 ) connected longitudinal link ( 7 ) additionally with frame-fixed displacement sensors ( 23 ) are articulated in connection, which can be registered as a stroke movement , vertical Schwenkbe movements of the trailing arm ( 7 ) indirectly via control signals to the control block ( 16 ) or the functional unit ( 29 ) of the hydropneumatic spring system ( 6 ). 10. Spring system according to one or more of the preceding claims 1 to 9, characterized in that the / with the displacement sensors ( 23 ) indirectly connected to the control block ( 16 ) or the functional unit ( 29 ) can be controlled by an electrical control unit ( 26 ) is. 11. Spring system according to one or more of the preceding claims 1 to 10, characterized in that each hydraulic spring cylinder ( 4 ) by means of a cylinder block ( 19 , 20 ) is attached to the vehicle frame ( 5 ), the cylinder blocks ( 19 , 20 ) are connected to one another by a common cross member ( 21 ). 12. Spring system according to one or more of the preceding claims 1 to 11, characterized in that for each front axle ( 1 , 2 ) a cylinder block ( 20 ) of a hydraulic spring cylinder ( 4 ) has an integrated Panhard rod connection ( 22 ) on which the front on the front axle ( 1 , 2 ) articulated Panhard rod ( 8 ) is articulated.