Air spring for controlling the level position of a driver's cabin or a motor vehicle

Abstract

An air spring includes a closing member, a rolling piston, and an air spring bellows connected to the rolling piston and the closing member to form a fluid-filled pressure chamber. A level control system for supplying and/or discharging fluid may be integrated into the pressure chamber to control level position based on air spring stroke. The level control system may have a control valve and an actuator connected to the control valve. The actuator may include a guide tube coupled to the rolling piston or closing member, and movably arranged within the pressure chamber. An actuating member may include a pin member and may operate the control valve. A compression spring may have a central spring and a biasing spring, and the guide tube may include a control flange coupled to the pin member, and the biasing spring may be supported to press the pin member against the control valve.

Claims

1. An air spring for controlling a level position of a driver's cabin or a motor vehicle, the air spring comprising: a closing member, a rolling piston, and an air spring bellows connected to the rolling piston and the closing member to form a fluid-filled pressure chamber, wherein a level control system for supplying and/or discharging fluid is integrated into the pressure chamber to control the level position of the driver's cabin or the motor vehicle depending on an air spring stroke; wherein the level control system has at least one control valve for supplying and/or discharging fluid to and/or from the pressure chamber, and an actuator that is operatively connected to the control valve; wherein the actuator includes a guide tube coupled to the rolling piston or the closing member and movably arranged within the pressure chamber, an actuating member formed as a pin member and configured to operate the control valve, and a compression spring; wherein the compression spring has a central spring coupled to the rolling piston or the closing member, and a biasing spring coupled to the pin member; and wherein the guide tube has a control flange to which the pin member is coupled and on which the biasing spring is supported to press the pin member against the control valve.

2. The air spring according to claim 1, wherein the pin member and the control flange are movable relative to each other, such that the control flange moves relative to the pin member during a rebound of the air spring over a first free travel and after overcoming the first free travel, the control flange entrains the pin member and moves it away from the control valve.

3. The air spring according to claim 1, wherein the pin member has an extension at a first end.

4. The air spring according to claim 3, wherein the extension comprises latching lugs.

5. The air spring according to claim 1, wherein the pin member has, at a second end, a peripheral shoulder on which the biasing spring is supported to press the pin member against the control valve.

6. The air spring according to claim 1, wherein the control valve has an exhaust valve and an inlet valve; and the pin member is operatively connected to the exhaust valve and the control flange is operatively connected to the inlet valve.

7. The air spring according to claim 6, wherein the actuator is configured so the inlet valve is closed and the exhaust valve is opened during a rebound, and the inlet valve is opened and the exhaust valve is closed during a deflection.

8. The air spring according to claim 6, wherein during a deflection, after overcoming a second free travel, the control flange is pressed against the inlet valve to open the inlet valve.

9. The air spring according to claim 6, wherein the actuator has another spring which is arranged between the control flange and the inlet valve and which presses the control flange away from the exhaust valve.

10. The air spring according to claim 1, wherein the central spring is arranged around the guide tube.

11. The air spring according to claim 1, wherein the rolling piston is connected to the guide tube via a flange, wherein the flange is supported on the central spring and is slidably mounted on the guide tube.

12. The air spring according to claim 1, wherein the guide tube has at least one projection which moves during a deflection and rebound within a channel that is introduced into the closing member or the rolling piston.

13. The air spring according to claim 1, wherein a damper is movably attached on the guide tube.

14. The air spring according to claim 1, wherein at least one opening is introduced into the guide tube.

15. The air spring according to claim 1, wherein the control flange has an oval contour.

16. An air spring for controlling a level position, the air spring comprising: a closing member, a rolling piston, and an air spring bellows connected to the rolling piston and the closing member to form a fluid-filled pressure chamber, the fluid-filled pressure chamber including a level control system for supplying and/or discharging fluid to and/or from the pressure chamber to control the level position depending on an air spring stroke; wherein the level control system has at least one control valve for supplying and/or discharging fluid into and/or out of the pressure chamber, and an actuator that is operatively connected to the control valve; wherein the actuator includes a guide tube coupled to the rolling piston or the closing member and movably arranged within the pressure chamber, an actuating member formed as a pin member and configured to operate the control valve, and a compression spring means; wherein the compression spring means includes a central spring coupled to the rolling piston or the closing member, and a biasing spring coupled to the control valve; and wherein the guide tube includes a control flange to which the pin member is coupled and on which the biasing spring is supported to press the pin member against the control valve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Hereinafter, the air spring and further features and advantages will be described with reference to an embodiment which is shown schematically in the accompanying figures. Hereby:

(2) FIG. 1 shows a longitudinal section through an air spring with a level control system;

(3) FIG. 2 shows an enlarged detail of the longitudinal section of the control valve of FIG. 1; and

(4) FIG. 3 shows a longitudinal section through the air spring, wherein the level control system is shown uncut.

DETAILED DESCRIPTION

(5) In FIG. 1, an air spring 10 is shown, which serves for controlling the level position of a driver's cab (not shown), or a motor vehicle (not shown).

(6) The air spring 10 has a closing member 12, a rolling piston 14 and an air spring bellows 16 interconnecting the closing member 12 and the rolling piston 14. The air spring bellows 16 is respectively fastened to the closing member 12 and the rolling piston 14 in an airtight manner via a clamping ring 18 and forms a pressure chamber 20 which is filled with fluid. The fluid can be air, in particular compressed air, gas or a compressible medium.

(7) The air spring 10 further includes a damper 22 whose piston rod 24 extends through the rolling piston 14 and is connected at its free end to a first elastomeric bearing 26. The air spring 10 is attached to a first vehicle part (not shown) by the first elastomeric bearing 26. A sealing ring 28 is provided between the rolling piston 14 and the piston rod 24 to seal the pressure chamber 20.

(8) In order to limit the deflection movement of the air spring 10, a buffer 72 which is penetrated by the piston rod 24 and supported on a bottom of the rolling piston 14 is arranged within the rolling piston 14. The buffer 72 interacts with a damper cap 74 arranged on the upper side of the damper 22.

(9) As can also be seen in FIG. 1, the damper 22 is connected to the closing member 12. In particular, the damper 22 extends through the closing member 12. Sealing rings 28 are provided between the closing member 12 and the piston rod 24 to seal the pressure chamber 20. At its end, protruding from the closing member 12, the damper 22 has a second elastomeric bearing 30, which serves to attach the air spring 10 to a second vehicle part (not shown).

(10) A level control system 32 for supplying and/or discharging fluid is also integrated into the pressure chamber 20 in the air spring 10 to control the level position of the motor vehicle or a driver's cabin as a function of air spring stroke.

(11) The level control system 32 has at least one control valve 34 for supplying and/or discharging fluid into and out of the pressure chamber 20 and an actuator 36 which is an operative connection with the control valve 34.

(12) The actuator 36 has a guide tube 38 coupled to the rolling piston 14 and movably arranged on the damper 22, an actuating member 40 which actuates the control valve 34, and a compression spring means 42.

(13) The guide tube 38 is connected to the rolling piston 14 via a flange member 44. The flange member 44 is formed as an annular disc and has a sleeve portion 45 located radially inwards which is slidably mounted on the guide tube 38. The rolling piston 14 is supported radially on the outside of the flange member 44. In order to prevent the flange member 44 from slipping off the guide tube 38, the guide tube 38 has tabs 47 at its end.

(14) At its end, facing the control valve 34, the guide tube 38 has a control flange 46 which is formed oval. Due to the oval contour of the control flange 46, the air spring bellows 16, which, in the pressureless state, are in the form of a tube, can simply be pulled over the control flange 46 for mounting the air spring 10.

(15) As can be seen in FIG. 2, the guide tube 38 has a projection 48, which is guided in channel 50 formed in the closing member 12. During deflection and rebound of the air spring 10, the projection 48 moves in the channel 50. This prevents rotation between the damper 22 and the actuator 36 during deflection and rebound.

(16) As can be seen in FIG. 3, the guide tube 38 has a plurality of openings 49. The openings 49 serve to cool the damper 22.

(17) The compression spring means 42 has a central spring 52 which surrounds the guide tube 38 and a biasing spring 54 which is associated with the control valve 34. Both springs are designed as compression springs, wherein the central spring 52 is biased stronger than the biasing spring 54. The flange 54 is supported on the central spring 52. The central spring 52 is supported on the control flange 46. The biasing spring 54 is coupled to the actuating member 40 and is supported over its entire surface on a bottom of the control flange 46.

(18) As can be seen in particular in FIG. 2, the actuating member 40 is formed as a pin member 56 which movably extends through a through hole 58 formed in the control flange 46.

(19) The pin member 56 has an extension 60 in the form of latching lugs 62 on the side facing away from the control valve 34. The latching lugs 62 are formed as pins 63 with thickenings 65 at their free ends. The pins 63 are separated by recesses 64, so that the latching lugs 62 are pivotable. The pin member 56 is attached to the control flange 46 via the latching lugs 62. For this purpose, the pin member 56 is inserted with the latching lugs 62 into the through opening 58. As a result, the latching lugs 62 are pressed together, so that the pin member 56 can be pushed through the through opening 58. When the latching lugs 62 emerge from the through opening 58, they pivot back into their original position and thus prevent the pin member 56 from being pulled out of the through opening 58.

(20) As can also be seen in FIG. 2, at the end facing a control valve 34, the pin member 56 has a peripheral shoulder 67 on which the biasing spring 54 is supported to press the pin member 56 against the control valve 34.

(21) The control valve 34 has an exhaust valve 66 and an inlet valve 68, both of which are designed as spring valves, the exhaust valve 66 being operatively connected to the pin member 56 and the inlet valve 68 being operatively connected to the control flange 46. As can also be seen from FIG. 2, a spring 70, associated with the actuator 36, is arranged between the control flange 46 and the inlet valve 68.

(22) When the exhaust valve 66 is opened, fluid is discharged from the pressure chamber 20 during rebound. When the inlet valve 68 is opened, fluid is supplied to the pressure chamber 20 during a compression. For this purpose, the inlet valve 68 is connected via a connector 69 with a fluid supply means (not shown)

(23) In the state shown in FIGS. 1 and 3, the exhaust valve 66 and the inlet valve 68 are closed by the pin member 56 being pressed against the exhaust valve 66 by the bias of the compression spring means 42 and the control flange 46 being spaced from the inlet valve 68. In order for the exhaust valve 66 to remain closed, the bias of the biasing spring 54 must be greater than the bias of the spring in the exhaust valve 66. To open the exhaust valve 66 during rebound, the guide tube 38 will be moved away from the control valve 34 due to the bias of the spring 70, wherein after overcoming a first free travel 76 from the control flange 46, the pin member 56 is entrained via the latching lugs 62 and thus moved away from the exhaust valve 66. To open the inlet valve 68 during a deflection, the control flange 46 presses on the inlet valve 68 after overcoming a second free travel 78 and the spring force of the spring 70.

(24) Hereinafter, the control of the level position of the air spring 10 by the level control system 32 will be described. In FIGS. 1 and 3, the neutral position of the air spring 10 is shown, in which the exhaust valve 66 and the inlet valve 68 are closed.

(25) During a compression or loading, the piston rod 24 moves into the damper 22 and at the same time the air spring bellows 16 rolls off on the rolling piston 14. As a result, the rolling piston 14 moves towards the closing member 12 downwards and thus exerts a force on the flange member 44. Since the flange member 44 is supported on the central spring 52, the central spring 52 exerts a pressure on the guide tube 38, so that the guide tube is moved towards the closing member 12. During deflection, the compression spring means 42 and the control flange 46 press the pin member 56 against the exhaust valve 66. As a result, the exhaust valve 66 is closed during deflection. At the same time the guide tube 38 moves due to the force induced by the central spring 52 on the closing member 12, wherein the control flange 46 compresses the spring 70. After overcoming the second free travel 78, the flange member 44 presses on the inlet valve 68. As a result, the inlet valve 68 is opened so that fluid flows via the inlet valve 68 into the pressure chamber 20. In a further deflection central spring 52 is compressed and thus takes over the rebound.

(26) During a rebound or discharge, the rolling piston 14 moves upwards away from the closing member 12, wherein the central spring 52 rebounds and presses the flange member 44 upwards. At the same time, the biasing spring 54 and the spring 70 press the guide tube 38 upwards. As long as the first free travel 76 is not overcome, the control flange 46 moves relative to the pin member 56, wherein the pin member 56 is further pressed against the exhaust valve 66 due to the bias of the biasing spring 54. After overcoming the first free travel 76, the biasing spring 54 is completely rebounded, so that only the spring 70 presses the guide tube 38 towards the rolling piston 14. After overcoming the first free travel 76, the control flange 46 entrains the pin member 56 via the latching lugs 62. Thereby, the pin member 56 is moved away from the exhaust valve 66 and the exhaust valve 66 is opened, so that fluid from the pressure chamber 20 flows into the surroundings.

(27) In the air spring 10, due to the structural design of the actuator 36, the biasing spring 54 can be supported over the entire surface on the control flange 46, so that the entire spring force of the biasing spring 54 presses on the pin member 56 and thus on the exhaust valve 66. Thereby, the spring force or the bias of the biasing spring 54 and the central spring 52 can be reduced. Thus, the compression spring means 42 of the air spring 10 has a small bias in total, whereby the comfort and the acoustic behaviour of the air spring 10 are improved. Due to the reduced bias of the compression spring means 42, the closing member 12 can be made thinner, which leads to a saving of material. In addition, a material with a lower rigidity or strength, such as PA6, can be used for the closing member 12 and/or the rolling piston 14, which leads to a cost saving. Moreover, the actuator 36 has a low number of parts, so that the installation costs of the air spring 10 are reduced. Furthermore, the diameter of the rolling piston 14 can be reduced, so that the rigidity of the air spring 10 can be presented in a wider range. Finally, due to the structural design of the actuator 36, more installation space is available for the damper cap 74, so that its diameter can be increased resulting in a higher service life of the buffer 72. In addition, the compression spring means 42, in particular the central spring 52, has a small spring travel.