Pneumatic cylinder with a self-adjusting end position damping arrangement, and method for self-adjusting end position damping
A self-adjusting end position damping arrangement includes a stroke space 9 which is delimited by a movable stroke element 7, 24 and a part of the pneumatic cylinder 1 , with the stroke space 9 being connected via a connecting duct 14 to the working pressure P 1 which acts on the cylinder piston 22 or to the ventilation pressure (P 3 ) in the outlet duct 3 and the stroke element 7, 24 being acted on via a damping duct 16 by the damping pressure P 2 in the damping volume 19 , a non-return valve 12 is arranged in the connecting duct 14 upstream of the stroke space 9 , which non-return valve 12 blocks in the direction of the working pressure P 1 or the ventilation pressure (P 3 ), respectively, and a ventilation duct 5 is provided, which ventilation duct 5 can be opened by means of the movable stroke element 7, 24 and which is connected to an outlet duct 3.
1. A pneumatic cylinder with a self-adjusting end position damping arrangement, comprising a cylinder housing ( 15 ) containing a movable cylinder piston ( 22 ) which divides the housing ( 15 ) into first and second variable-volume chambers ( 40 , 50 ), the first chamber ( 40 ) formed in part by a first side of the piston and which contains a piston fluid at a working pressure (p 1 ) which acts on the first side of the piston, and the second chamber ( 50 ) formed in part by an opposite second side of the piston and containing said end position damping arrangement in which a damping volume ( 19 ) which is delimited by the non-pressurized side of the cylinder piston ( 22 ) is formed in the region of the end position of the cylinder piston ( 22 ) as a result of the movement of the cylinder piston ( 22 ), said damping volume containing fluid at a damping pressure (P 2 ), wherein the end position damping arrangement comprises a stroke space ( 9 ) which is delimited by a movable stroke element ( 7 , 24 ) and a part of the pneumatic cylinder ( 1 ), with a connecting duct ( 14 ) which extends from the stroke space ( 9 ) to the first chamber ( 40 ) containing the fluid at working pressure (P 1 ) which acts on the cylinder piston ( 22 ) or to ventilation pressure (P 3 ) in an outlet duct ( 3 ), the stroke element ( 7 , 24 ), which is movable inside the stroke space, being acted on at a side facing toward the stroke space ( 9 ) by the working pressure (P 1 ) and on an opposite side being acted on by damping pressure (P 2 ) in the damping volume ( 19 ) via a damping duct ( 16 ), including a non-return valve ( 12 ) in the connecting duct ( 14 ) upstream of the stroke space ( 9 ), which non-return valve ( 12 ) blocks in the direction of the working pressure (P 1 ) or ventilation pressure (P 3 ), respectively, and encloses an air volume in the stroke space ( 9 ) and generates a gas spring effect caused by the movement of the stroke element ( 7 , 24 ) and including a ventilation duct ( 5 ) which can be opened by means of the movable stroke element ( 7 , 24 ) and which is connected to the outlet duct ( 3 ), whereas the stroke element ( 7 , 24 ) is controls the opening of the ventilation duct ( 5 ) depending on the damping pressure (P 2 ).
2. The pneumatic cylinder according to claim 1 , including a damping pin ( 18 ) which extends in an axial direction into the cylinder housing ( 15 ) in the region of the end stop of the cylinder piston ( 22 ), and the cylinder piston ( 22 ) is formed with a recess ( 23 ) which can receive the damping pin ( 18 ).
3. The pneumatic cylinder according to claim 1 , wherein the outlet duct ( 3 ) is positioned laterally on the cylinder housing ( 15 ) and axially spaced apart from a cylinder cover ( 4 ).
4. The pneumatic cylinder according to claim 3 , wherein the stroke element is formed as a damping piston ( 7 ) which is mounted in a guided fashion in the stroke space ( 9 ).
5. The pneumatic cylinder according to claim 4 , wherein the stroke space ( 9 ) is in a cylinder cover ( 4 ) which closes off the pneumatic cylinder ( 1 ).
6. The pneumatic cylinder according to claim 4 , wherein the stroke space ( 9 ) is in the piston ( 22 ).
7. The pneumatic cylinder according to claim 2 , including an elastic sealing element ( 24 ) as a stroke element between the damping pin ( 18 ) and cylinder piston ( 22 ), with the sealing element ( 24 ) being hollow and being arranged in the cylinder piston ( 22 ).
8. The pneumatic cylinder according to claim 1 , including a ventilation opening ( 17 ) on the pneumatic cylinder ( 1 ), which ventilation cross section ( 17 ) is connected to the damping volume ( 19 ).
9. The pneumatic cylinder according to claim 1 , including a self-adjusting end position damping arrangement at both end positions of the cylinder piston ( 22 ).
10. A method for self-adjusting end position damping of a cylinder piston which moves in a cylinder housing of a pneumatic cylinder and is subjected on a first side by a working pressure (P 1 ), and by way of an opposite second side forms a damping volume in a region of an end position of the cylinder piston as a result of movement of the cylinder piston, said cylinder housing defining a stroke space in which a stroke element moves, said method comprising the steps of:
moving the cylinder piston towards the end position to generate a damping pressure (P 2 ) in the damping volume,
supplying said damping pressure (P 2 ) to a first end of the stroke space to act on a first end of the stroke element,
supplying said working pressure (P 1 ) to an opposite second end of the stroke space to act on an opposite second end of the stroke element,
moving said stroke element based on pressures (P 1 ) and (P 2 ) to open or close a ventilation duct which extends between the stroke space and an outlet duct.
11. A pneumatic cylinder having self-adjusting end position damping comprising:
a cylinder housing having first and second ends,
an end cover at said second end of said cylinder housing, and
a piston which is moveable in said cylinder housing to define first and second variable-volume chambers on opposite sides thereof, said first chamber containing a fluid at working pressure (p 1 ), said piston moving toward said end cover by said working pressure (P 1 ) in said cylinder housing and defining a damping volume with said end cover,
said end cover defining an outlet duct for the discharge of fluid from within said cylinder housing, a stroke chamber, a ventilation duct which connects a first end of said stroke chamber with said outlet duct, a damping duct which connects said first end of said stroke chamber with said damping volume, a connecting channel which extends from a second end of said stroke chamber to said first chamber containing working pressure (P 1 ), and a non-return valve in said connecting channel which prevents fluid flow out of said stroke chamber, and
a damping piston in said stroke chamber for controlled movement therein based on said working pressure (P 1 ) and said damping pressure (P 2 ) acting on opposite ends thereof, controlled movement of said damping piston relative to said ventilation duct controlling the flow of fluid from the stroke chamber to the outlet duct and thus the lowering of the damping pressure (P 2 ) and the movement of the piston towards the end cover.
12. The pneumatic cylinder according to claim 11 , wherein said piston defines a recess facing the end cover, and wherein said end cover includes a damping pin which extends towards said piston to fit with said recess, said outlet duct extending in said damping pin.
13. The pneumatic cylinder according to claim 11 , wherein said cylinder housing includes a connecting duct which communicates with said connecting channel.