FLUID DAMPER INCLUDING A SWITCHING PISTON, METHOD FOR MANUFACTURING THE FLUID DAMPER, DRIVE ARRANGEMENT INCLUDING THE FLUID DAMPER

Abstract

A fluid damper is provided including a cylinder filled with a damping fluid, a piston base body shiftably guided in the cylinder along a stroke axis, and a valve disk spaced apart from a shell wall of the cylinder. The piston base body divides an inner space of the cylinder into a front space and a rear space along the stroke axis. In the piston base body, there is at least one channel connecting the front space to the rear space in a fluid-conducting manner. The valve disk is shiftably guided along the stroke axis between an opening position unblocking the at least one channel and a closing position closing the at least one channel. The valve disk has a central area extending radially outward from the stroke axis, the central area being free of apertures.

Claims

1. A fluid damper, comprising: a. a cylinder filled with a damping fluid; b. a piston base body shiftably guided in the cylinder along a stroke axis; and c. a valve disk spaced apart from a shell wall of the cylinder; d. the piston base body dividing an inner space of the cylinder into a front space and a rear space along the stroke axis; e. at least one channel connecting the front space to the rear space in a fluid-conducting manner being arranged in the piston base body; f. the valve disk being shiftably guided relative to the piston base body along the stroke axis between an opening position unblocking the at least one channel and a closing position closing the at least one channel; g. the valve disk having a central area extending radially outward from the stroke axis, the central area being free of apertures; wherein h. the fluid damper comprises a stopper attached to the piston base body for limiting the shiftability of the valve disk relative to the piston base body in an opening direction from the closing position to the opening position; and i. the stopper comprises a number of semi-spherical or conically tapered protrusions for reducing a contact surface between the stopper and the valve disk.

2. The fluid damper according to claim 1, wherein the aperture-free central area extends outwards from the stroke axis up to a central area radius, the central area radius amounting to 50% to 100% of a valve disk radius of the valve disk radial to the stroke axis.

3. The fluid damper according to claim 1, wherein the valve disk has a number of apertures for the passage of the damping fluid through the valve disk along the stroke axis outside of the central area.

4. The fluid damper according to claim 3, wherein the number of apertures are ring segment-shaped and/or radially open towards the outside from the stroke axis.

5. The fluid damper according to claim 1, wherein a guide member is fixed to the piston base body and arranged between the valve disk and a shell wall of the cylinder, the guide member shiftably guiding the valve disk along the stroke axis between the opening position and the closing position.

6. The fluid damper according to claim 1, wherein the fluid damper comprises a spring member arranged between the valve disk and the piston base body which urges the valve disk into the opening position along the stroke axis, the valve disk being shiftable from the opening position into the closing position against the spring member by a positive pressure in the front space relative to the rear space when the positive pressure exceeds a switching pressure.

7. The fluid damper according to claim 6, wherein the spring member is arranged in a recess in the piston base body.

8. The fluid damper according to claim 7, wherein the recess has a smaller diameter than the valve disk transverse to the stroke axis.

9. The fluid damper according to claim 1, wherein the valve disk is elastically deformable in the closing position by a positive pressure in the front space relative to the rear space so that the valve disk unblocks the at least one channel when the positive pressure exceeds an override pressure.

10. The fluid damper according to claim 1, wherein the valve disk directly abuts on the piston base body in the closing position, a contact surface between the valve disk and the piston base body being ring-shaped.

11. The fluid damper according to claim 1, wherein the fluid damper comprises a piston rod fixed to the piston base body, the piston base body sectionally enclosing the piston rod radial to the stroke axis and being fixed to the piston rod by shaping the piston base body towards the stroke axis.

12. A method for manufacturing the fluid damper according to claim 11, comprising: shaping of the piston base body of the fluid damper towards the stroke axis of the fluid damper for fixing the piston base body to the piston rod of the fluid damper.

13. A drive arrangement for a flap of a motor vehicle comprising at least one motorised drive for moving the flap, wherein the drive arrangement comprises at least one fluid damper according to claim 1 for supporting the flap.

Description

BRIEF DESCRIPTION

[0057] Some of the embodiments will be described in detail, with references to the following Figures, wherein like designations denote like members, wherein:

[0058] FIG. 1 shows a schematic longitudinal cross-sectional view along the stroke axis of an embodiment of the fluid damper;

[0059] FIG. 2 shows a schematic longitudinal cross-sectional view along the stroke axis of an embodiment of the switching piston of the fluid damper in the opening position;

[0060] FIG. 3 shows a schematic longitudinal cross-sectional view along the stroke axis of another embodiment of the switching piston of the fluid damper in the closing position;

[0061] FIG. 4 shows a schematic longitudinal cross-sectional view along the stroke axis of another embodiment of the switching piston of the fluid damper in the closing position; and

[0062] FIG. 5 shows a schematic plan view along the stroke axis of another embodiment of the switching piston of the fluid damper.

DETAILED DESCRIPTION

[0063] FIG. 1 shows a schematic longitudinal cross-sectional view along a stroke axis H of an embodiment of a fluid damper 100.

[0064] The fluid damper 100 comprises a cylinder 110 filled with a damping fluid (not illustrated), for example with a gas having a positive pressure, a piston base body 120 shiftably guided in the cylinder 110 along the stroke axis H, and a valve disk 130 spaced apart from of a shell wall 113 of the cylinder 110.

[0065] The piston base body 120 divides an inner space of the cylinder 110 into a front space 111 and a rear space 112 along the stroke axis H, at least one channel (not illustrated) connecting the front space 111 to the rear space 112 in a fluid-conducting manner being disposed in the piston base body 120.

[0066] The fluid damper 100 comprises a seal 122 attached to the piston base body 120 and encircling the stroke axis H which seals the piston base body 120 with respect to the shell wall 113 of the cylinder 110 in a fluid-tight manner.

[0067] The valve disk 130 is shiftably guided relative to the piston base body 120 along the stroke axis H between an opening position unblocking the at least one channel 121 and a closing position closing the at least one channel 121.

[0068] The fluid damper 100 comprises a spring member 150, for example a helical compression spring, arranged between the valve disk 130 and the piston base body 120. The spring member 150 urges the valve disk 130 into the opening position along the stroke axis H, the valve disk 130 being shiftable from the opening position into the closing position against the spring member 150 by a positive pressure in the front space 111 relative to the rear space 112 when the positive pressure exceeds a switching pressure.

[0069] The spring member 150 is arranged in a recess 123 in the piston base body 120, for example in a bore coaxial to the stroke axis H.

[0070] The fluid damper 100 comprises a piston rod 170 fixed to the piston base body 120 which is lead out of the cylinder 110 through the rear space 112.

[0071] On the end of the piston rod 170 not attached to the piston base body 120 as well as on the end of the cylinder 110 on which the piston rod 170 is not lead out of the cylinder 110, respectively, a connecting member 180, for example a spherical socket, is arranged to mechanically connect the fluid damper 100 to other components, for example to a flap and a chassis of a vehicle.

[0072] FIG. 2 shows a schematic longitudinal cross-sectional view along the stroke axis of an embodiment of the switching piston of the fluid damper 100 in the opening position. Components already shown in FIG. 1 are designated by the same reference numerals as in FIG. 1 and not described again.

[0073] In FIG. 2, the channel 121 in the piston base body 120 connecting the front space 111 to the rear space 112 in a fluid-conducting manner is illustrated. The channel 121 comprises, for example, a bore radial to the stroke axis H which connects the recess 123 in which the spring member 150 is arranged to the rear space 112 in a fluid-conducting manner.

[0074] The fluid damper 100 shown in FIG. 2 comprises a guide member 140 fixed to the piston base body 120 and disposed between the valve disk 130 and a shell wall 113 of the cylinder 110, for example a guide sleeve coaxial to the stroke axis H. The guide member 140 shiftably guides the valve disk 130 along the stroke axis H between the opening position shown in FIG. 2 and the closing position.

[0075] The guide member 140 comprises a stopper 141, for example a protrusion encircling the stroke axis H and oriented towards the stroke axis H for limiting the shiftability of the valve disk 130 relative to the piston base body 120 in an opening direction from the closing position to the opening position.

[0076] In the embodiment shown in FIG. 2, the piston base body 120 sectionally encloses the piston rod 170 radial to the stroke axis H. The piston base body 120 is fixed in a groove 171 of the piston rod 170 on the piston rod 170 by shaping towards the stroke axis H.

[0077] FIG. 3 shows a schematic longitudinal cross-sectional view of another embodiment of the switching piston of the fluid damper 100 in the closing position along the stroke axis H. The components already illustrated in FIG. 1 or 2 are designated by the same reference numerals provided there and will not be described again.

[0078] The fluid damper 100 shown in FIG. 3 comprises a support member 190 for supporting the guide member 140 on the piston base body 120. The support member 190 is, for example, connected to the piston base body 120 via a latch connection, and positively connected to the guide member 140.

[0079] FIG. 4 shows a schematic longitudinal cross-sectional view of another embodiment of the switching piston of the fluid damper 100 in the closing position along the stroke axis. The components already illustrated in FIG. 1, 2, or 3 are designated by the same reference numerals as provided there and will not be described again.

[0080] In the embodiment shown in FIG. 4, the stopper 141 for the valve disk 130 comprises a number of, for example three, protrusions 142 for reducing a contact surface between the stopper 141 and the valve disk 130. The protrusions 142 are, for example, semi-spherical.

[0081] FIG. 5 shows a schematic plan view of another embodiment of the switching piston of the fluid damper 100 along the stroke axis H. The components already illustrated in FIG. 1, 2, 3, or 4 are designated by the same reference numerals as provided there and will not be described again.

[0082] In FIG. 5, the valve disk 130 has a central area 131 extending radially outward from the stroke axis H, the central area 131 being formed free of apertures, i.e., without apertures along the stroke axis H.

[0083] Outside of the central area 131, the valve disk 130 shown in FIG. 5 has a number of, for example three, apertures 132 for the passage of the damping fluid through the valve disk 130 along the stroke axis H. The apertures 132 are, for example, ring segment-shaped and radially open towards the outside from the stroke axis H.

[0084] Between adjacent apertures 132, a bridge 133 is arranged, respectively, which may serve for guiding the valve disk 130 on the guide member 140.

TABLE-US-00001 List of reference numerals 100 Fluid damper 110 Cylinder 111 Front space 112 Rear space 113 Shell wall 120 Piston base body 121 Channel 122 Seal 123 Recess 130 Valve disk 131 Central area 132 Aperture 133 Bridge 140 Guide member 141 Stopper 142 Protrusion 150 Spring member 160 Seal member 170 Piston rod 171 Groove 180 Connecting member 190 Support member H Stroke axis