DE102017102714B4 - Air spring or air spring damper - Google Patents

Abstract

Air spring or air spring damper (10) for a vehicle or a driver's cab, having a rolling piston (12), a cover element (14), an air spring bellows (16), the rolling piston (12) and the cover element (14) forming a fluid-filled Pressure chamber (18) connects, and a level control system (22) for regulating the level of the vehicle or the driver's cab, the level control system (22) having an inlet valve (24) for supplying fluid to the pressure chamber (18), an outlet valve (26) for Removal of fluid from the pressure chamber (18) and an actuating device (28) which is in operative connection with the inlet valve (24) and / or the outlet valve (26) and the inlet valve (24) and / or the outlet valve (26) in Depending on the air spring stroke opens and / or closes, a residual pressure holding valve (48) being integrated into the outlet valve (26), the outlet valve (26) and the residual pressure holding valve (48) being connected in series, the Residual pressure holding valve (48) is connected downstream of the outlet valve (26) and wherein the residual pressure holding valve (48) is followed by a sound-damping device (56).

Description

The present invention relates to an air spring or an air spring damper for a vehicle or a driver's cab, comprising a rolling piston, a cover element, an air spring bellows which connects the rolling piston and the cover element to form a pressure chamber filled with fluid, and a level control system for regulating the level of the vehicle or the driver's cab.

An air spring or an air spring damper of the type mentioned at the beginning cushions two mutually movable parts and thereby increases the suspension comfort of vehicles or driver's cabs. A conventional air spring has an air spring bellows made of rubber, which is connected to a cover element and a rolling piston in order to form an airtight sealed pressure space. The pressure chamber is filled with a fluid, in particular compressed air, as the working medium. During compression and rebound, the air spring rolls on the outer surface of the rolling piston and thus cushions the vibrations that are introduced.

In addition to this suspension function, an air spring can also have a damping function. Such an air spring can also be referred to as an air spring damper. The damping function can be implemented in that the working medium flows back and forth between the pressure chamber and a further chamber, which is usually formed in the rolling piston, via a damping channel with a narrowed cross section. The induced vibrations are dampened by the resulting friction. In addition, the damping function can also be implemented by integrating a separate hydraulic damper into the air spring.

In addition, an air spring or an air spring damper can also be used to keep a desired level position of a motor vehicle or a driver's cab constant or to change it in an adjustable manner with different loads or weight loads. The pressure in the pressure chamber is changed as a function of the air spring stroke by supplying or draining the working medium. This is done via control valves that can be arranged inside or outside the air spring or the air spring damper.

So goes out DE 2011 108 249 A1 an air spring which has a mechanically actuatable control valve integrated into the air spring for controlling the level position of a motor vehicle or a driver's cab. The control valve is attached to a cover element and comprises control valves for regulating the compressed air supply or the compressed air discharge. The pressure regulating valves are actuated via cams that are mounted in a rotatable camshaft. The rotary movement of the camshaft takes place via a rocker arm, which rests with its free end on a bearing surface on the rolling piston of the air spring. The camshaft is rotated by the pivoting movement of the rocker arm, whereby, depending on the compression or extension of the air spring, one of the cams actuates one of the tappets of the control valves held closed by spring forces.

It also goes out DE 10 2011 114 570 A1 an air spring arrangement with an integrated valve control for controlling the level of a motor vehicle or a driver's cab. The integrated valve control comprises an air inlet valve and an air outlet valve, which are arranged in the area of a cover element, a compression spring device which is designed in two parts is provided for opening and closing the valves. The compression spring device has a central spring facing the rolling piston or the cover element and a control valve biasing spring facing the air outlet valve. The central spring and the control valve pretensioning spring are arranged on a guide tube that is freely movably mounted axially between the rolling piston and the cover. A radially protruding stop is provided between the two springs and serves as a control means for actuating the valve tappet of the inlet valve. The compression spring device is held between the tensioning means, one of the tensioning means making contact with the outlet valve. During compression, the guide tube slides downwards, and at the same time the control valve pretensioning spring is compressed until the stop, after bridging an idling, contacts the outlet valve and actuates it. In the event of a rebound, the guide tube moves upwards, the control valve pretensioning spring rebounding so that the tensioning means assigned to the outlet valve moves away from it and the outlet valve is opened.

The DE 199 40 038 B4 discloses a level control device for a vehicle with air springs, comprising a pressure medium source for filling the air springs with air, a valve device for controlling the level at which the air springs can be connected to a pressure medium source or the atmosphere. The valve device has a residual pressure holding valve and a 3/2-way valve. Both the 3/2-way valve and the residual pressure holding valve are designed as controllable solenoid valves.

From the DE 10 2009 044 456 A1 shows an air spring which discloses a mechanically actuatable residual pressure holding valve.

There are situations in which an air spring or an air spring damper is completely deflated. For example, when the air spring or the air spring damper is used to support a driver's cab and the driver's cab has to be tilted for maintenance work. During the tilting process, the air spring or the air spring damper is completely emptied. If, in the completely deflated state, the air spring or the air spring damper is compressed or pulled apart, this leads to the formation of creases in the air suspension bellows. This can damage the air bag. The present invention is based on the object of creating an improved air spring or an improved air spring damper.

To achieve the object, an air spring or an air spring damper with the features of claim 1 is proposed.

The dependent claims relate to advantageous configurations of the air spring or the air spring damper.

The invention relates to an air spring or an air spring damper for a vehicle or a driver's cab, having a rolling piston, a cover element, an air spring bellows which connects the rolling piston and the cover element to form a pressure chamber filled with fluid, and a level control system for regulating the level of the vehicle or the driver's cab. The level control system has at least one inlet valve for supplying fluid into the pressure chamber, an outlet valve for discharging fluid from the pressure chamber and an actuating device which is in operative connection with the inlet valve and / or the outlet valve and the inlet valve and / or the outlet valve as a function opens and / or closes from the air spring stroke. A residual pressure retention valve is integrated in the outlet valve. The outlet valve and the residual pressure holding valve are connected in series, the residual pressure holding valve being connected downstream of the outlet valve and a sound damping device being connected downstream of the residual pressure holding valve.

By integrating a residual pressure holding valve in the outlet valve, a certain amount of fluid always remains in the pressure chamber, so that a certain residual pressure is always maintained in the pressure chamber. This prevents the air suspension bellows from being compressed or pulled apart without pressure, so that the air suspension bellows is protected from damage. The integrated unit of outlet valve and residual pressure holding valve creates a simple and inexpensive valve that on the one hand maintains the function of the outlet valve for level control and on the other hand ensures that a predetermined residual pressure remains in the air spring while the air spring is being vented.

If the weight load changes, the level control system enables the level to be kept constant or changed. For this purpose, the actuating device is designed in such a way that it actuates the inlet valve and / or the outlet valve as a function of the air spring stroke, so that fluid is supplied to or removed from the pressure chamber. In normal operation, i.e. in spring operation, the outlet valve and the inlet valve are closed. During a lowering of the level position, for example during loading, the outlet valve remains closed and the actuating device opens the inlet valve so that fluid can flow into the pressure chamber in order to raise the level position. For this purpose, the inlet valve can be connected to a fluid source. During an increase in the level, for example during unloading, the actuating device closes the inlet valve again and opens the outlet valve so that air can flow into the environment via the open outlet valve. If the pressure falls below a predetermined limit pressure, for example while the pressure chamber is being emptied, the residual pressure holding valve closes so that a certain residual pressure remains in the pressure chamber. Accordingly, the residual pressure holding valve works independently of the level of the air spring or the air spring damper.

The actuating device can be arranged inside the air spring. The actuation device can be a mechanical and / or electrical actuation device. A mechanical actuation device can be a compression spring device, as shown in DE 10 2011 114 570 B4 is known. Furthermore, the mechanical actuation device can be a spring-loaded guide rod. An electrical actuating device can be an electrical servomotor and / or an electromagnet.

The outlet valve and the residual pressure holding valve are advantageously designed as spring valves, the springs acting in the direction of the air spring's longitudinal axis. The opening and closing force as a function of the pressure can be set in a simple and reliable manner via the spacing between the spring forces. In addition, the valves can also have a multi-stage design.

According to the invention, the outlet valve and the residual pressure holding valve are connected in series. As a result of the series connection, the outlet valve and the residual pressure holding valve can be integrated in a valve, in particular in a valve housing. The outlet valve is preferably directly facing the pressure chamber, while the residual pressure holding valve is facing the environment.

According to the invention, the residual pressure holding valve is also connected downstream of the outlet valve. As a result, the fluid flows from the pressure chamber first through the outlet valve and then through the residual pressure holding valve into the environment.

Furthermore, the outlet valve has a soundproofing device. The sound-absorbing device reduces the generation of noise when fluid flows out of the pressure chamber via the outlet valve into the environment. The sound attenuation device is connected downstream of the residual pressure control valve, which can be done in series.

In an advantageous embodiment, the actuating device is designed in such a way that the actuating device opens the inlet valve when the level falls below a predetermined level and that the actuating device opens the outlet valve when a predetermined level is exceeded. Accordingly, the actuating device closes the outlet valve and opens the inlet valve when the level falls below a predetermined level, whereas the actuating device opens the outlet valve and closes the inlet valve when a predetermined level is exceeded. In normal operation, the actuating device closes both the outlet valve and the inlet valve.

In an advantageous embodiment, the direction of action of the outlet valve and / or the residual pressure holding valve is in the direction of the longitudinal axis of the air spring. As a result, the two valves act in the spring direction of the air spring or the air spring damper. In the present case, the effective direction is understood to mean the closing and opening directions of the outlet valve and the residual pressure holding valve. The air spring longitudinal axis is understood to mean the spring direction of the air spring or of the air spring damper acting in the axial direction.

In an advantageous embodiment, the residual pressure holding valve and the outlet valve close in opposite directions. The opposite closing direction requires both valves to close reliably.

In an advantageous embodiment, a pressure for opening the residual pressure holding valve is between 0.1 bar and approx. 5 bar, preferably between 0.5 bar and 2.5 bar. Since the residual pressure valve only opens above a specified pressure, a certain residual pressure always remains within the pressure chamber when the air spring or air spring damper is vented, so that pressure-free compression and / or pulling apart and thus wrinkling and damage to the air bag is avoided. The pressure for opening the residual pressure holding valve is advantageously set via the spring force.

In an advantageous embodiment, the outlet valve has a valve housing with an outlet channel introduced therein for discharging fluid from the pressure chamber, a valve tappet displaceable within the valve housing for closing the outlet channel and a first spring element, the first spring element being coupled to the valve tappet and the valve tappet pushes away from the outlet channel into an open position. Thus, the spring force of the first spring element is responsible for the fact that the outlet valve is open in a rebound position. In normal operation and when the level falls below a predetermined level, the actuating device presses the valve tappet against the spring force of the first spring element against the outlet channel in order to close the same. This closes the outlet channel so that no more fluid can flow from the pressure chamber into the environment. A first space for receiving the valve tappet and the first spring element is advantageously formed in the valve housing. The first spring element can be a compression spring. The first spring element can be a spiral spring or an elastomeric spring. The valve tappet can be provided with a closing element for closing the outlet channel.

In an advantageous embodiment, the residual pressure holding valve has a closure element movable within the valve housing to close the outlet channel and a second spring element, the second spring element being coupled to the closure element and pressing the closure element against the outlet channel into a closed position. As a result, the outlet valve closes the outlet channel when the pressure within the pressure chamber falls below a value corresponding to the spring force of the second spring element. As a result, a complete outflow of the fluid from the pressure chamber into the environment is avoided. As soon as the pressure in the pressure chamber is greater than the spring force of the second spring element, the closure element is pressed against the spring force of the second spring element into an open position, so that the fluid can flow from the pressure chamber into the environment via the outlet valve. In an advantageous embodiment, the closure element is designed as a sealing membrane. A second space is advantageously formed within the valve housing, within which the closure element and the second spring element are arranged, the second space being connected via the outlet channel to the first space in which the valve tappet and the first spring element are arranged. The second room is advantageously connected directly to the surroundings. The closure element can be a sealing membrane which is pretensioned by means of the second spring element.

In an advantageous embodiment, the valve housing is made of a plastic, in particular a fiber-reinforced plastic. As a result, the valve has a low weight and is inexpensive to manufacture.

In an advantageous embodiment, the ratio of a diameter of the closure element to a smallest diameter of the outlet channel is between 1 and 15. The ratio is set in such a way that reliable closure of the outlet channel is ensured.

In an advantageous embodiment, in the closed position of the outlet valve and in the closed position of the residual pressure holding valve, the pressure in the outlet channel is between approx. 0 bar and approx. 2.5 bar. This is the case when the outlet valve is closed via the actuating device and the residual pressure holding valve closes automatically due to the low pressure present in the outlet channel.

The sound-damping device is also advantageously arranged in the second space of the valve housing, the second spring element being supported on the sound-damping device. The sound attenuation device can be made of wool, foam, felt or a sintered material. Furthermore, the sound attenuation device can be an empty space formed within the valve housing.

In an advantageous embodiment, the outlet valve is integrated in the rolling piston or in the cover element, a sealing element being arranged between the outlet valve and the rolling piston or the cover element. The inlet valve can also be integrated in the rolling piston or the cover element. The sealing element can be a sealing ring which rests in a groove in the valve housing.

• 1 einen Längsschnitt durch einen Luftfederdämpfer; und
• 2 einen vergrößerten Ausschnitt des in 1 gezeigten Auslassventils.

In the following, an air spring damper and further features and advantages are explained in more detail on the basis of exemplary embodiments which are shown schematically in the figures. Here show:

• 1 a longitudinal section through an air spring damper; and
• 2 an enlarged section of the in 1 exhaust valve shown.

In 1 is an air spring damper 10 shown, which is used for damping and regulating a level of a vehicle (not shown) or a driver's cab (not shown).

The air spring damper 10 has a rolling piston 12th , a cover element 14th and an air bag 16 on that of the rolling piston 12th and the cover element 14th with the formation of an airtight sealed pressure space 18th connects with each other. The printing room 18th is filled with a fluid as the working medium. Compressed air can be used as the working medium.

As also in 1 can be seen is within the pressure chamber 18th a hydraulic damper 20th arranged, which serves to dampen the vibrations introduced. To regulate the level of a vehicle (not shown) or a driver's cab (not shown), the air spring damper 10 a level control system 22nd on. The level control system 22nd has an inlet valve 24 for feeding fluid into the pressure chamber 18th , an exhaust valve 26th for discharging fluid from the pressure chamber 18th and an actuator 28 on that with the inlet valve 24 and / or the outlet valve 26th is in operative connection. In the present case, both valves are designed as spring valves.

The actuator 28 has a compression spring device 30th on. Such a compression spring device 30th is off, for example DE 10 2011 114 570 B4 known. The inlet valve 24 is in the lid member 14th integrated and connected to a fluid source (not shown), in particular a compressed air source, to the pressure chamber 18th to apply fluid.

As in 2 can be seen is the exhaust valve 26th in the cover element 14th integrated, with the exhaust valve 26th into one in the cover element 14th trained receiving opening 32 is used positively and / or non-positively. The exhaust valve 26th has a valve housing 34 with a first recording room 36 , a second recording room 38 and one of the two recording rooms 36 , 38 interconnecting exhaust duct 40 on. The valve body 34 can be made of plastic, in particular fiber-reinforced plastic.

The first recording room 36 is the pressure room 18th assigned, being in the first receiving space 36 one relative to the valve housing 34 sliding valve tappet 42 and a first spring element 44 , which is designed as a compression spring, in particular as a spiral spring, are arranged. The valve lifter 42 is at the end with a closing element 45 provided that the exhaust port 40 securely locks.

In 2 is the exhaust valve 26th shown in a closed position, the actuating device 28 to close the outlet duct 40 the valve lifter 42 in a first closing direction S ₁ against the force of the first spring element 44 pushes so that the closing element 45 at one at the entrance of the exhaust duct 40 provided first sealing seat 46 is applied. In spring operation, the presses Actuator 28 the valve lifter 42 against the force of the first spring element 44 to the sealing seat 46 so that the exhaust valve 26th closed is. The actuating device only moves away when a predetermined level is exceeded 28 from the exhaust valve 26th so that the first spring element 44 the valve lifter 42 from the sealing seat 46 moved away and fluid from the pressure chamber 18th via the exhaust duct 44 can flow into the environment.

As also in 2 As can be seen, there is a residual pressure holding valve in the outlet valve 48 integrated that the exhaust valve 26th is connected in series. The residual pressure holding valve 48 is within the second receiving space 38 arranged and has a within the valve housing 34 movable closure element 50 to close the outlet duct 40 and a second spring element 52 on. The second spring element 52 is designed as a compression spring, in particular as a spiral spring, and in this way with the closure element 50 coupled that it is the closure element 50 to close the outlet duct 40 in a second closing direction S ₂ presses. In particular, the second spring element presses 52 the closure element against one at the outlet of the outlet channel 40 provided second sealing seat 54 presses. The two closing directions are accordingly S ₁ , S ₂ opposite to each other.

The spring force of the second spring element 52 is matched so that the residual pressure retention valve 48 at one inside the pressure chamber 18th The prevailing pressure of between approx. 0.1 bar and approx. 5 bar, preferably between approx. 0.5 bar and 2.5 bar, opens and the outlet channel 40 releases. The closure element 50 is dimensioned so that the ratio of diameter D1 of the exhaust duct 40 too diameter D2 of the closure element 50 is between 1 and 15. If both the exhaust valve 46 as well as the residual pressure control valve 48 is closed, the pressure inside the outlet channel is 40 between 0 bar and approx. 2.5 bar.

To avoid noise when the fluid is out of the pressure chamber 18th flows into the environment, the outlet valve 26th a sound attenuation device 56 on. The soundproofing device 56 is the residual pressure control valve 26th downstream and within the second recording room 38 arranged. As in 2 can be seen is the soundproofing device 56 plate-shaped, wherein the second spring element 52 on the soundproofing device 56 supports. The soundproofing device is for this purpose 56 into one in the valve housing 34 introduced circumferential groove 58 used. The soundproofing device 56 can be made of wool, foam, felt, or a sintered material. Furthermore, it is also conceivable that the soundproofing device 56 is formed as an empty space within the valve housing 34 is trained.

The valve body 34 is made of a plastic, in particular a fiber-reinforced plastic. The exhaust valve 26th , the residual pressure retention valve 48 and the muffler 56 form an integrated unit, with a cover element for sealing 60 between the valve body 34 and the cover element 14th is arranged. The level control and the residual pressure maintenance function of the air spring damper are described below 10 described. The inlet valve is in normal operation 24 and the exhaust valve 26th closed. The air bag rolls during compression and rebound 16 on the rolling piston 12th off so that the pressure chamber 18th is compressed. As a result, the vibrations are cushioned and / or dampened. If the level falls below a specified level, the outlet valve remains 26th closed and the actuator 28 opens the inlet valve 24 . This causes fluid to flow over the inlet valve 24 in the printing room 18th . As a result, the pressure in the pressure chamber increases 18th , so that a vehicle (not shown) or a driver's cab (not shown) is raised. When a predetermined level is exceeded, the inlet valve is 24 closed and the actuator 28 opens the outlet valve 26th . This allows fluid to flow through the outlet valve 26th pour into the environment. At the same time, the air bag rolls 16 on the rolling piston 12th so that the vehicle or the driver's cab is lowered. When the pressure in the pressure room 18th falls below a predetermined value, the residual pressure holding valve closes 48 the exhaust valve 40 so that a certain residual pressure in the pressure chamber 18th remains. This causes wrinkling and damage to the air bag 16 avoided.

List of reference symbols

10

Air spring damper

12th

Rolling piston

14th

Cover element

16

Air bag

18th

Printing room

20th

hydraulic damper

22nd

Level control system

24

Inlet valve

26th

outlet valve

28

Actuator

30th

Compression spring device

32

Receiving opening

34

Valve body

36

first recording room

38

second recording room

40

Exhaust duct

42

Valve lifters

44

first spring element

45

Closing element

46

first sealing seat

48

Residual pressure retention valve

50

Closure element

52

second spring element

54

second sealing seat

56

Soundproofing device

58

Groove

60

Sealing element

D1

Outlet duct diameter

D2

Closing element diameter

S1

first closing direction

S2

second closing direction

Claims (9)

Air spring or air spring damper (10) for a vehicle or a driver's cab, having a rolling piston (12), a cover element (14), an air spring bellows (16), the rolling piston (12) and the cover element (14) forming a fluid-filled Pressure chamber (18) connects, and a level control system (22) for regulating the level of the vehicle or the driver's cab, the level control system (22) having an inlet valve (24) for supplying fluid to the pressure chamber (18), an outlet valve (26) for Removal of fluid from the pressure chamber (18) and an actuating device (28) which is in operative connection with the inlet valve (24) and / or the outlet valve (26) and the inlet valve (24) and / or the outlet valve (26) in Depending on the air spring stroke opens and / or closes, a residual pressure holding valve (48) being integrated into the outlet valve (26), the outlet valve (26) and the residual pressure holding valve (48) being connected in series, the Residual pressure holding valve (48) is connected downstream of the outlet valve (26) and wherein the residual pressure holding valve (48) is followed by a sound-damping device (56). Air spring or air spring damper (10) Claim 1 , characterized in that the direction of action of the outlet valve (26) and / or of the residual pressure holding valve (48) is in the direction of the longitudinal axis of the air spring. Air spring or air spring damper (10) according to one of the preceding claims, characterized in that the residual pressure holding valve (48) and the outlet valve (26) close in opposite directions. Air spring or air spring damper (10) according to one of the preceding claims, characterized in that a pressure for opening the residual pressure holding valve (48) between approx. 0.1 bar and approx. 5 bar, preferably between approx cash. Air spring or air spring damper (10) according to one of the preceding claims, characterized in that the outlet valve (26) has a valve housing (34) with an outlet channel (40) introduced therein for discharging fluid from the pressure chamber (18), one inside the valve housing ( 34) has a displaceable valve tappet (42) for closing the outlet channel (40) and a first spring element (44), the first spring element (44) being coupled to the valve tappet (42) and the valve tappet (42) being connected to the outlet channel (40) pushes away into an open position. Air spring or air spring damper (10) Claim 5 , characterized in that the residual pressure holding valve (48) has a closure element (50) movable within the valve housing (34) for closing the outlet channel (40) and a second spring element (52), the second spring element (52) with the closure element (50) ) is coupled and the closure element (50) presses against the outlet channel (40) into a closed position. Air spring or air spring damper (10) Claim 6 , characterized in that the ratio of a diameter of the closure element (50) to a smallest diameter of the outlet channel (40) is between 1 and 15. Air spring or air spring damper (10) Claim 6 or 7th , characterized in that in the closed position of the outlet valve (26) and in the closed position of the residual pressure holding valve (48) the pressure in the outlet channel (40) is between approx. 0 bar and approx. 2.5 bar. Air spring or air spring damper (10) according to one of the preceding claims, characterized in that the outlet valve (26) is integrated in the rolling piston (12) or the cover element (14), wherein between the outlet valve (26) and the rolling piston (12) or a sealing element (60) is arranged on the cover element (14).

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