Piston-cylinder unit

Patent metadata

Field	Value
Publication number	US-9334918-B2
Application number	US-201414179192-A
Country	US
Kind code	B2
Filing date	Feb 12, 2014
Priority date	Feb 15, 2013
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

A piston-cylinder unit includes: a cylindrical pressure tube having a first end side defining an end side opening; a piston, axially displaceable in the pressure tube, the piston having a piston rod, the piston rod being guided out of the pressure tube at the first end side through the end side opening; a piston rod guide and a piston rod seal, arranged inside the pressure tube, which cooperate together to sealingly guide the piston rod at the end side opening; and a cup-like protective cap surrounding an end region of the cylindrical pressure tube from the first end side, the protective cap having a base at its end, the base having a coaxial through-orifice having an inner wall through which the piston rod extends in a displaceable manner. The inner wall of the through-orifice tightly surrounds the piston rod.

First claim

What is claimed is:

1. A piston-cylinder unit comprising:
a cylindrical pressure tube ( 1 ) having a first end side ( 5 ) defining an end side opening ( 13 ), the cylindrical pressure tube ( 1 ) having a surface protection on at least a portion of its outer surface;
a piston ( 7 ), axially displaceable in the pressure tube ( 1 ), the piston ( 7 ) having a piston rod ( 8 ), the piston rod ( 8 ) being guided out of the pressure tube ( 1 ) at the first end side ( 5 ) through the end side opening ( 13 );
a piston rod guide and a piston rod seal, arranged inside the pressure tube ( 1 ), which cooperate together to sealingly guide the piston rod at the end side opening ( 13 ); and
a cup-like protective cap ( 15 ) surrounding an end region ( 6 ) of the cylindrical pressure tube ( 1 ) from the first end side ( 5 ), the protective cap ( 15 ) having a base ( 18 ) at its end, the base ( 18 ) having a coaxial through-orifice ( 19 ) having an inner wall through which the piston rod ( 8 ) extends in a displaceable manner,
wherein:
the inner wall of the through-orifice ( 19 ) tightly surrounds the piston rod ( 8 ),
the outer surface of the cylindrical pressure tube ( 1 ) at the end region ( 6 ) is excluded from the surface protection, the outer surface of the cylindrical pressure tube ( 1 ) at end region ( 6 ) being coated with a corrosion inhibitor ( 16 ),and
the protective cap ( 15 ) comprises a radially circumferential elastic seal ( 20 ) arranged at the inner wall of the through-orifice ( 19 ), the radially circumferential elastic seal ( 20 ) having a sealing edge ( 22 ) wherein a first side of the sealing edge ( 22 ), distal from the pressure tube ( 1 ), is steeply inclined toward a free end of the piston rod ( 8 ), with respect to a longitudinal axis ( 25 ) of the piston rod, and a second side of the sealing edge ( 22 ), facing the pressure tube ( 1 ), is shallowly inclined away from the free end of the piston rod ( 8 ), with respect to the longitudinal axis ( 25 ) of the piston rod ( 8 ).

2. The piston-cylinder unit according to claim 1 , wherein the protective cap ( 15 ) comprises an elastomer at least in the area of the through-orifice ( 19 ).

3. The piston-cylinder unit according to claim 2 , wherein the protective cap ( 15 ) comprises, at least in the area of the through-orifice ( 19 ), a material that is flexible in a temperature range between approximately −40° C. and approximately +130° C.

4. The piston-cylinder unit according to claim 1 , wherein the protective cap ( 15 ) and the radially circumferential elastic seal ( 20 ) are integrally formed.

5. The piston-cylinder unit according to claim 1 , wherein the radially circumferential elastic seal ( 20 ) comprises one or more radially circumferential sealing lips ( 17 ).

6. The piston-cylinder unit according to claim 5 , wherein each sealing lip ( 17 ) has a sealing edge ( 22 ) surrounding the piston rod ( 8 ) accompanied by pre-loading.

7. The piston-cylinder unit according to claim 6 , wherein the sealing edge ( 22 ) has a V-shaped cross section.

8. The piston-cylinder unit according to claim 1 , wherein the protective cap ( 15 ) has a cuff-like projection ( 14 ) that projects away from the pressure tube ( 1 ) coaxially proceeding from the base ( 18 ) of the protective cap ( 15 ), the circumferential elastic seal ( 20 ) being arranged at the cuff-like projection ( 14 ) of the protective cap ( 15 ).

Assignees

• Ackermann Stefan
• Schilz Arnold
• Stabilus Gmbh

Inventors

• Ackermann Stefan
• Schilz Arnold

Classifications

• F16F9/19

  with a single cylinder {and of single-tube type} · CPC title

• F16F9/3242 Primary

  of cylinder ends, e.g. caps · CPC title

• F16F9/38 Primary

  Covers for protection or appearance · CPC title

• F15B15/1461

  Piston rod sealings · CPC title