Working cylinder

1 . A working cylinder, comprising:

a cylinder having a cylinder tube, a closure part and a further closure part, said cylinder tube with said closure parts defining a cylinder interior, said cylinder tube having a cylinder tube end and a further cylinder tube end, said closure part being provided at said cylinder tube end and said further closure part being provided at said further cylinder tube end;

a piston unit defining at least one working chamber in said cylinder interior;

said closure part having an axial closure part ring surface with a shaft portion extending therefrom, said shaft portion having a base end at said ring surface and a free end opposite said base end and said cylinder tube having a cylinder tube end portion, said shaft portion and said cylinder tube end portion defining a coupling section with a proximal zone and a distal zone and in said coupling section said closure part is axially inserted with said shaft portion into said cylinder tube at said cylinder tube end portion,

said shaft portion having a conicity with a greatest shaft diameter at said free end, said shaft portion having, at least in sections of the conicity, an overdimension relative to an inner diameter of said cylinder tube, and said cylinder tube having an elastic circumferential expansion at said cylinder tube end portion,

said coupling section being configured for coupling said closure part and said cylinder tube in an axially force-fit and form-fit, said cylinder tube end being connected to said closure part in a positive-substance manner by a circumferential ring weld seam, said ring weld seam being a laser weld seam defining a pressure medium-tight sealing plane.

2 . The working cylinder according to claim 1 , wherein said cylinder tube has an axial cylinder tube ring surface, said ring surfaces define a common contact ring surface, said ring weld seam is provided radially on said contact ring surface.

3 . The working cylinder according to claim 2 , wherein said cylinder tube ring surface has an inclination angle that ranges between 0.1 and 1 degree.

4 . The working cylinder according to claim 1 , wherein the elastic circumferential expansion of said cylinder tube in said proximal zone is 0.02% to 0.5%.

5 . The working cylinder according to claim 1 , wherein said closure part has a higher modulus of elasticity than said cylinder tube.

6 . The working cylinder according to claim 1 , wherein said closure part has a closure part inlet chamfer or said cylinder tube has a cylinder tube inlet chamfer.

7 . The working cylinder according to claim 1 , wherein the conicity of said shaft portion has a conicity angle that ranges between 0.1 and 1 degree relative to a main longitudinal axis of said cylinder tube.

8 . A working cylinder, comprising:

a cylinder having a cylinder tube, a closure part and a further closure part, said cylinder tube with said closure parts defining a cylinder interior, said cylinder tube having a cylinder tube end and a further cylinder tube end, said closure part being provided at said cylinder tube end and said further closure part being provided at said further cylinder tube end;

a piston unit defining at least one working chamber in said cylinder interior,

said closure part having a shaft portion and said cylinder tube having a cylinder tube end portion, said shaft portion and said cylinder tube end portion defining a coupling section with a proximal zone and a distal zone and in said coupling section said closure part being axially inserted with said shaft portion into said cylinder tube at said cylinder tube end portion,

said shaft portion having a conicity, the conicity being configured to increase distally, said shaft portion being overdimensioned along the conicity relative to said inner diameter of said cylinder tube in said distal zone of said coupling section with a maximum overdimension occurring in said distal zone, and said cylinder tube having an elastic circumferential expansion in said distal zone;

said coupling section being configured for coupling said closure part and said cylinder tube in an axially force-fit and form-fit, said cylinder tube end being connected to said closure part in a positive-substance manner by a circumferential ring weld seam, said ring weld seam being a laser weld seam defining a pressure medium-tight sealing plane.