EP3790747A1

EP3790747A1 - Damper unit for a chassis of a vehicle with levelling

Info

Publication number: EP3790747A1
Application number: EP19724077.3A
Authority: EP
Inventors: Alex Kalnitski; Gregor Mader; Franz Peter; Sebastian Tippl
Original assignee: Elektronische Fahrwerksysteme GmbH
Current assignee: E:FS TECHHUB GMBH
Priority date: 2018-05-07
Filing date: 2019-05-03
Publication date: 2021-03-17
Also published as: CN112243413A; US11970034B2; CN112243413B; KR20210002707A; WO2019214770A1; US20210331544A1; KR102536091B1; DE102018110916A1

Abstract

The invention relates to a damper unit (10) for a chassis (100) of a vehicle with levelling, comprising a hydraulic cylinder (1) having a container tube (2) which is filled with a damper fluid and in which a piston (3) is movably mounted and separates an upper container space (21) from a lower container space (22). The piston (3) comprises a first valve (41) through which the damper fluid flows when the piston (3) moves in a first direction A. The damper unit (10) further comprises an accumulator (5) and a check valve (6), wherein the accumulator (5) is connected to the container tube (2) via the check valve (6) in such a manner that, when the piston (3) moves in at least one direction, damper fluid is pumped through the check valve (6) into the accumulator (5).

Description

Damper unit for a chassis of a vehicle

with level control

The invention relates to a damper unit for a chassis of a vehicle with level control according to the independent claim.

The invention is concerned with the technical field of motor vehicles with level chassis, in particular with the problem of changing the level position of the vehicle by means of the vehicle damper in the implementation of the level function.

Conventional dampers for a motor vehicle include a hydraulic cylinder in which a piston is movably arranged in a container tube filled with damper fluid (oil, gas, etc.). The container tube is directly connected to the wheel and the piston rod is fixed to the body.

The relative movement between the wheel (or suspension) and the body is damped by the piston in each case a hydraulic valve for flowing through fluid for the pulling direction (distance between wheel to body increases) and a hydraulic valve for the pressure direction (distance from wheel to body decreases ) opens. It is by the movement of the piston by the outer Suggestions / influences introduced into the chassis / induced energy (vibration energy) in the form of heat free and remains unused.

A disadvantage with conventional dampers is that the energy released during the damping of the suspension vibration remains unused. First, DE 15 30 531 C is known from the prior art.

From the prior art, DE 2 83 00 75 A1 discloses a vehicle in which the energy of the axle oscillation is stored by means of an electrical converter. In this case, an induction current is generated by means of a correspondingly formed coil arrangement in an axis movement. The induction current provides the electrical energy for use by electrical consumers. This solution is a complicated and error-prone construction, in which only little electrical energy from the axle vibration for the electrical consumers, such. B. a pump for a chassis, is provided. Therefore, the operation of a ride-on is not described therein. It is the object of the present invention to provide a damper unit for a chassis of a vehicle with level control, which uses energy derived from the damping of the vehicle and is simple in construction.

This object is achieved by a damper unit for a chassis of a vehicle with level control according to the independent claim. Advantageous aspects form the subject of the respective subclaims.

The invention comprises a damper unit for a chassis of a vehicle with a level control. The damper unit (actuator unit) comprises a hydraulic cylinder with a container tube filled with a damper fluid, in which a piston is movably arranged and separates an upper container space and a lower container space. The piston comprises a (single) first valve for flowing through the damper fluid upon movement of the piston in a first direction (A, pull direction or pressure direction). The damper unit further includes a pressure accumulator and a check valve. The accumulator is connected via the check valve in such a way with the container tube that during a movement of the piston, in at least one direction, damper fluid is pumped through the check valve into the pressure accumulator. By pumping the damper fluid through the check valve into the accumulator, the pressure level in the accumulator increases. The damper fluid under this increased pressure may be directed into a reservoir space to move (eg, lift) the piston, thereby changing the height level of the vehicle. The damper unit thus provided utilizes the energy induced during vehicle movement in a simple manner to actuate a chassis for a vehicle with level control.

According to an advantageous aspect of the pressure accumulator is connected via the check valve on the upper tank space with the container tube. Upon movement of the piston (upward) in the direction of the piston rod damper fluid is pumped through the check valve in the pressure accumulator. Thus, the energy dissipated during the damping of the restoring movement of the chassis or during rebounding can be stored for the level control.

Another advantageous aspect of the invention provides that the piston rod via a spring is indirectly or directly clamped against the container tube. In the event that the piston rod is tensioned by a spring directly against the container tube, the advantages described can be realized on a compact damper unit. For example, while the spring may be arranged lying around the piston rod. In the event that the piston rod is indirectly stretched by a spring against the container tube, the spring may be arranged adjacent to the piston rod.

A technically preferred aspect of the invention provides that the pressure accumulator comprises a pressure-limiting unit (eg a pressure-limiting valve). The pressure limiting unit does not allow the pressure in the accumulator to rise above a predetermined threshold. For this purpose, the pressure limiting unit can drain the hydraulic fluid when the threshold value is exceeded or feed it back to the container tube. Another aspect provides that the damper unit further comprises a reservoir for the damper fluid. Generally, the reservoir is a volume which can absorb and release damper fluid with minimal pressure change. The pressure limiting unit is arranged between pressure accumulator and the reservoir. The reservoir can be kept at a predetermined pressure level.

A particularly preferred aspect provides that the reservoir is a non-pressurized reservoir. In this technical context, pressureless means that only atmospheric pressure prevails. According to another preferred technical aspect, the pressure accumulator is a pneumatic pressure accumulator. For example, the pressure accumulator is a hermetically sealed container in which a predetermined volume of compressed air can be kept. This volume of compressed air can be selected individually according to the needs and size of the damper unit. A preferred example is a hydropneumatic pressure accumulator, in which a container of a flexible

Partition is divided into two chambers. In one chamber is the pressurized damper fluid (liquid) and in the other chamber is a gas, such as nitrogen. In such an energy storage, the energy delivered when lowering the vehicle height can be recorded and then made available again.

Alternatively or additionally, the pressure accumulator may be a mechanical pressure accumulator in which, for example, mechanical deformation energy is stored in a spring (such as a coil spring).

Particularly preferably, the pressure limiting unit is designed such that it has an opening pressure. Advantageously, the pressure limiting unit is designed such that the opening pressure is adjusted so that the chassis can still be adjusted on the maximum fleas due to the energy stored in the pressure accumulator. Another particularly preferred aspect provides that the pressure limiting unit is designed such that it has an adjustable opening pressure. The setting can be adjusted, for example, according to the terrain type used.

Further, the pressure limiting unit may include a throttle unit and / or an aperture unit to control the damper fluid. In the simplest case, the pressure limiting unit itself is designed as a throttle valve.

According to a further advantageous technical aspect, the damper unit comprises a switching valve (eg further check valve, adjustable spring-loaded check valve, switching unit), a further pressure accumulator and a further pressure-limiting unit (adjustable pressure-limiting unit). Functionally, check valve is also a switching unit or a switching valve to understand. First, the accumulator, which is closer to the cylinder, filled without the subsequently connected further pressure accumulator is filled. If the first accumulator filled, not overpressure is discharged, but the overpressure is used to fill the additional pressure accumulator via another check valve with a defined opening pressure. The pressure or the under pressure damper fluid of the further pressure accumulator can be used via a switchable valve to reach the low level and concomitant filling of the first pressure accumulator.

Particularly preferably, the damper unit further comprises a pump unit. The pump unit preferably comprises a hydraulic pump or a pneumatic pump (with electrical control). Upper and lower damper chambers are connected via a pump unit which conveys towards the upper pump chamber. This allows an adjustment of the level without induced roadway excitation (eg in the state).

According to a further advantageous aspect, the invention also includes a chassis with a plurality of damper units (as described herein). Each damper unit includes a pressure accumulator. Preferably, at least two damper units comprise a common pressure accumulator. A technically advantageous aspect provides that the accumulators and the reservoirs are fluidly (hydraulically) connected via valves, throttles or orifices.

In the following the invention will be explained in more detail with reference to FIGS. The reference numerals are used the same in all figures. All variants can be combined with each other. Showing:

Figure 1 is a schematic representation of a damper unit for a chassis of a vehicle with level control according to an embodiment of the invention. FIG. 2 shows a variant of the damper unit from FIG. 1 with a throttle unit and a diaphragm unit; FIG.

FIG. 3 shows a variant of the damper unit from FIG. 1 with a pump unit; FIG. 4 shows a further variant of the damper unit from FIG. 1 with an electrically actuated pump unit; Fig. 5 shows an additional variant of the damper unit of Fig. 1 with two

Accumulators; and

Fig. 6 shows a chassis with two damper units.

Fig. 1 shows a damper unit 10 according to an embodiment of the invention. In a motor vehicle, four damper units 10, that is, one per wheel, can be used to realize a chassis (see Fig. 6) with level control.

The damper unit 10 comprises a hydraulic cylinder 1 with a damper fluid (eg hydraulic fluid) filled container tube 2. In the container tube 2, a piston 3 is arranged to be movable. The piston 3 is guided in such a fluid-tight manner on the inner wall of the container tube 2 that it is separated from the piston 3 moving therein into an upper container space 21 and into a lower container space 22 (fluidically). In the piston 3, a first valve 41 is provided for flowing through the damper fluid during a movement of the piston 3 in a first direction A. In the example shown, the first valve 41 is designed in the manner of a throttle valve, which opens downwards in the direction of (pressure) movement upon movement of the piston in order to allow a flow of damper fluid from the lower reservoir chamber 22 into the upper reservoir chamber 21.

The damper unit 10 has a pressure accumulator 5 and a check valve 6, wherein the check valve 6 is connected to the upper tank space 21 and connects it to the pressure accumulator 5. The check valve 6 acts to open upward upon movement of the piston in the (pulling) direction to allow flow of damper fluid from the upper tank space 21 into the pressure accumulator. In this way damper fluid is pumped through the check valve 6 in the pressure accumulator 5 while the spring 7 relaxes. The accumulator 5 is a pneumatic pressure accumulator. The damper unit 10 thus provided utilizes the energy induced by vehicle motion in a simple manner to actuate a chassis (see FIG. 6) for a vehicle with a level control.

In the variant shown, in which the accumulator 5 is connected via the check valve 6 at the upper reservoir chamber 21 to the container tube 2, during the movement of the piston 3 in the downward direction (away from the piston rod 31) damper fluid through the valve 41 in pumped in the upper reservoir space and a movement upward (in the direction of the piston rod 31) through the check valve 6 in the pressure accumulator 5. In principle, this device also works in the opposite direction when the valves and the pressure accumulator adapted accordingly and connected to the lower tank space become. In the variant shown, the directly attached to the vehicle body piston rod 31 is tensioned by a spring 7 against the container tube 2.

Below the pressure accumulator 5, a pressure limiting unit 8 is arranged, which is connected to a reservoir 9. In the example shown, the pressure limiting unit 8 has a predetermined and / or regulated opening pressure, from which opens this. This can damage the Accumulator 5 can be avoided due to an overpressure. The opening pressure is selected in the pressure limiting unit 8 so as to ensure a complete lowering (maximum stroke from a high position of the chassis to a low position of the chassis) of the chassis (and vice versa to achieve a high level). It can be provided that the pressure limiting unit 8 has an adjustable / regulated opening pressure, which can be selected, for example, according to the payload.

A variant of the damper unit 10 just described is shown in FIG. The damper unit 10 comprises a pressure accumulator 5, which is connected via a check valve 6 to the container tube 2. The pressure accumulator 5 is connected to a pressure limiting unit 8, which in turn is connected to a reservoir 9, in which the excess damper fluid is introduced after exceeding a predetermined pressure in the pressure accumulator 5. Between the hydraulic valve 8 and the reservoir 9 sit a throttle unit 82 and / or a diaphragm unit 83. The damper unit 10 comprises an additional check valve 13 between the reservoir 9 and the container tube 2.

FIGS. 3 and 4 show two further variants of the damper unit 10 just described with a pump unit. According to the example in Fig. 3 is generally a pump unit with a pump 23, which is arranged in a the upper tank space 21 and the lower tank space 22 connecting pipe branch 231. By operating the pump 23, the low level / height level can be adjusted even without vibration excitation, for example, in the state. 4, the damper unit 10 includes a pneumatic (or hydraulic) pump 24 with an (electronic) control 241. Another variant is shown in Fig. 5, wherein the damper unit 10 includes a further (eg, spring-loaded) check valve 61, a further pressure accumulator 51 and a further (eg switchable) pressure limiting unit 81. The further check valve 61 is arranged between the pressure accumulator 5 and the pressure limiting unit 8. The further check valve 61 opens at a lower pressure than the pressure limiting unit 8. At the other Check valve 61, the further pressure accumulator 51 connects, which in turn is connected to the further pressure-limiting unit 81. The further pressure-limiting unit 81 is connected to the upper tank space 21. Due to the further pressure accumulator 51, the possibility of storing energy can be increased.

The aspect of the invention relating to the chassis 100 is shown in Fig. 6, wherein two damper units 10 are shown. Thus, for example, the axis (front axle or flinter axle) of a vehicle (not shown) can be realized. The two pressure accumulators 5 are fluidly coupled to each other via a throttle unit 82 (additive or alternatively aperture unit). This ensures a uniform pressure that allows a uniform level adjustment in all damper units. Likewise, the respective reservoirs 9 are fluidically coupled to each other, so that an exchange of the damper fluid is made possible. In the illustration shown, the reservoirs 9 are coupled to one another via a throttle unit 82.

Claims

claims

A damper unit (10) for a chassis (100) of a vehicle having a level control, comprising a hydraulic cylinder (1) having a damper fluid filled reservoir tube (2) in which a piston (3) is movably disposed and an upper reservoir space (21 ) and a lower reservoir space (22), and wherein the piston (3) comprises a first valve (41) for flowing through the damper fluid upon movement of the piston (3) in a first direction (A), which damper unit (10) further a pressure accumulator (5) and a check valve (6), wherein the pressure accumulator (5) via the check valve (6) is connected to the container tube (2) such that upon movement of the piston (3) in at least one direction damper fluid through the check valve (6) is pumped into the accumulator (5).

2. damper unit (10) according to claim 1, wherein the pressure accumulator (5) via the check valve (6) on the upper container space (21) with the container tube (2) is connected, so that upon movement of the piston (3) in the direction of Piston rod (31) damper fluid is pumped through the check valve (6) in the pressure accumulator (5).

3. damper unit (10) according to claim 1 or 2, wherein the piston rod (31) via a spring (7) directly or indirectly against the container tube (2) is tensioned.

4. damper unit (10) according to one of the preceding claims, wherein the pressure accumulator (5) comprises a pressure limiting unit (8).

5. damper unit (10) according to claim 4, further comprising a reservoir (9), wherein the pressure limiting unit (8) between the pressure accumulator (5) and the reservoir (9) is arranged, and wherein the damper unit (10) an additional switching valve (13 ) between the reservoir (9) and the container tube (2).

6. damper unit (10) according to claim 5, wherein the reservoir (9) is a non-pressurized reservoir.

7. damper unit (10) according to one of the preceding claims, wherein the pressure accumulator (5) is a pneumatic pressure accumulator.

8. damper unit (10) according to one of claims 1 to 5, wherein the pressure accumulator (5) is a mechanical pressure accumulator.

9. damper unit (10) according to one of claims 4 to 8, wherein the

Pressure limiting unit (8) is designed such that it has a predetermined opening pressure.

10. damper unit (10) according to one of claims 4 to 8, wherein the pressure limiting unit (8) is designed such that it has an adjustable opening pressure.

11. damper unit (10) according to one of claims 4 to 10, wherein the pressure-limiting unit (8) comprises a throttle unit (82) and / or a diaphragm unit (83).

12. damper unit (10) according to one of the preceding claims, further comprising a further check valve (61), a further pressure accumulator (51) and a further pressure-limiting unit (81).

13. damper unit (10) according to one of the preceding claims, further comprising a pump unit, wherein the pump unit comprises a pump (23), in particular a hydraulic pump or a pneumatic pump (24).

14. Suspension (100) with a plurality of damper units (10) according to one of the preceding claims, wherein each damper unit (10) comprises a pressure accumulator (5) or wherein at least two damper units (10) comprise a single pressure accumulator (5).

15. Landing gear (100) according to one of claims 13 or 14, wherein the

Pressure accumulator (5) and the unpressurized reservoirs (9) are each hydraulically connected via valves, throttles or orifices.