A fluid damper including a switching piston, a method for manufacturing the fluid damper, and a drive device including the fluid damper.

Abstract

The present invention relates to a fluid damper (100) comprising a cylinder (110) filled with damping fluid, a piston base (120) movably guided within the cylinder (110) along a stroke axis (H), and a valve disc (130) spaced apart from a shell wall (113) of the cylinder (110). The piston base (120) divides the internal space of the cylinder (110) along the stroke axis (H) into a front space (111) and a rear space (112). The piston base (120) has at least one channel (121) that conducts fluid between the front space (111) and the rear space (112). The valve disc (130) is movably guided (121) relative to the piston base (120) along the stroke axis (H) between an open position that releases the at least one channel (121) and a closed position that closes the at least one channel. The valve disc (130) has a central region (131) extending radially outward from the stroke axis (H), and the central region (131) has no through holes.

Description

Technical Field

[0001] This invention relates to a fluid damper comprising a cylinder filled with damping fluid, a piston base movably guided within the cylinder along a stroke axis, and a valve disc spaced apart from the cylinder wall. Along the stroke axis, the piston base divides the internal space of the cylinder into a front space and a rear space. The piston base has at least one channel for fluid conduction communication between the front space and the rear space. The valve disc is movably guided along the stroke axis between an open position (unblocking the at least one channel) and a closed position (closing the at least one channel).

[0002] The present invention also relates to a method for manufacturing a fluid damper and a drive device including the fluid damper. Background Technology

[0003] In single-sided valve actuators, compression damping is typically provided on the passive side (suspension strut) to handle failures on the driven side. Compression damping should only be activated at a defined threshold to prevent harmful permanent damping forces during normal operation. In automatic tailgates, this threshold is only slightly above the normal sliding speed.

[0004] In the described application, the gas spring, as an adjustment component, will add additional restraint / closure to protect the entire system or the user from excessive exposure / speed (in case of collision, excessive operating speed, etc.) during high-speed sliding.

[0005] Known gas springs with speed-dependent damping forces involve too many components to be extended to smaller diameter gas springs. Due to the large number of components and the superposition of error tolerances, the switching point is inaccurate. Furthermore, due to the large number of components involved, they have relatively large inertia and high friction, resulting in unstable switching characteristics.

[0006] Document EP0409094A1 describes a fluid damper comprising a switching piston attached to a piston rod and a base including a circumferential seal. The base is formed as a guide sleeve in which a disc-shaped valve body has an annular through-hole and a central through-hole, which can move from an open position to a closed position opposite to the stroke axis of the fluid damper to the spring element, thereby closing the valve through the base.

[0007] Documents DE10140580A1, DE19649836A1, US5730260A, and DE102006030064A1 also disclose fluid dampers comprising a switching piston, the switching piston having a base attached to a piston rod and including a circumferential seal. The switching piston also includes a valve body movably guided along the stroke axis of the fluid damper on the base, moving from an open position to a closed position, closing a passage through the base. Summary of the Invention

[0008] The purpose of this invention is to provide a fluid damper that is as simple and cost-effective as possible and has a reliable manufacturing method, wherein the fluid damper reliably brakes the sliding speed of the piston of the fluid damper above a precisely defined switching speed.

[0009] This invention provides a fluid damper that solves the aforementioned technical objective. Similarly, the objective is achieved through a method for manufacturing the fluid damper and a drive device including the fluid damper.

[0010] The fluid damper includes a cylinder filled with damping fluid. Preferably, the damping fluid is a gas and / or pressurized relative to the environment of the cylinder. The cylinder is preferably formed as a pressure tube.

[0011] The fluid damper includes a piston base that is movably guided within a cylinder along a stroke axis. The cylinder is preferably formed as a hollow cylinder and / or arranged coaxially with the stroke axis.

[0012] The fluid damper includes a valve disc spaced apart from the cylinder housing wall. The valve disc is preferably disc-shaped, particularly circular, and / or oriented perpendicularly to the stroke axis. The stroke axis preferably extends through the center point of the valve disc.

[0013] Because the valve disc is spaced apart from the housing wall, the switching function of the valve disc is not affected by the friction between the valve disc and the housing wall, thus achieving more precise switching characteristics. Furthermore, the spacing allows for a larger throttling cross-section and a lower valve spring force, thereby achieving a precise switching point and low resistance during normal operation, as well as less oil droplet interference in the small cross-section.

[0014] The valve disc is preferably arranged in a groove in the piston base, for example, in the inner bore of the piston base coaxial with the stroke axis. Arranging it in a groove prevents contact between the valve disc and the cylinder, which could affect the switching characteristics of the valve disc.

[0015] The piston base divides the internal space of the cylinder into a front space and a rear space along the stroke axis. The piston base has at least one channel for fluid conduction between the front and rear spaces. Preferably, this at least one channel is the only fluid conduction connection between the front and rear spaces. When the piston base moves within the cylinder along the stroke axis, damping fluid can flow from the front space into the rear space through the channel, and vice versa. Here, the flow resistance of the damping fluid in the channel determines the damping force of the fluid damper against the movement of the piston base. Therefore, the flow resistance determines how much damping force the fluid damper uses to resist the movement of the components relative to each other, which are connected to each other by the fluid damper.

[0016] The fluid damper is preferably configured such that when the piston base slides into the fluid damper, it moves from the rear space to the front space along the sliding direction. The front space and the rear space can be interchanged.

[0017] The valve disc can be movably guided relative to the piston base along the stroke axis between an open position that releases the at least one channel and a closed position that closes the at least one channel. The terms "release" and "close" refer to a significant reduction in the minimum cross-sectional area of ​​the channel for damping fluid in the closed position relative to the open position, for example, a reduction of 75% to 100%, particularly 85% to 100%, preferably 95% to 99%.

[0018] Preferably, the channel is not completely closed in the closed position, so that the piston base is not stuck in the cylinder, but can move slowly, for example, to slowly close a valve disc supported by a fluid damper.

[0019] Therefore, the piston base and valve disc together form a switching piston, which increases the damping force of the fluid damper by moving the valve disc from the open position to the closed position. Compared with the prior art, the switching function can be advantageously implemented with fewer parts, thereby simplifying the manufacture of the switching piston. Preferably, due to the conventional system design and the simple (stamped and / or machined) and fewer parts, for example, the switching piston has five parts instead of the six parts in known switching pistons, the fluid damper requires less development effort.

[0020] When the positive pressure in the front space relative to the rear space exceeds the switching pressure, the valve disc preferably moves from the open position to the closed position. As an example, the positive pressure is the back pressure generated when the piston base moves along the stroke axis from the rear space to the front space in a sliding direction. Back pressure is generated when the volumetric flow rate of the damping fluid discharged through the movement of the piston base is greater than the volumetric flow rate that can pass through the channel.

[0021] When the piston base moves at a speed exceeding the switching speed, the positive pressure exceeds the switching pressure, causing the valve disc to move to the closed position. In this way, the damping force of the fluid damper increases and the movement of the piston base is braked, thereby preventing excessive speeds that could lead to damage to the fluid damper or its connected components, or the risk of personal injury.

[0022] Preferably, the speed of the piston body after switching to the closed position can be adjusted by the minimum cross-sectional area of ​​the channel in the closed position.

[0023] Preferably, the valve disc is in the open position when the positive pressure in the front space is lower than the switching pressure, or when there is a negative pressure in the front space relative to the rear space. This means that when the piston base moves in the sliding direction at a speed lower than the switching speed, or when the piston base moves in the sliding out direction opposite to the sliding in direction, the damping force of the fluid damper is low. Therefore, the components interconnected by the fluid damper can move relative to each other at any speed and with low energy consumption in the sliding in and sliding out directions at a speed lower than the switching speed. In this way, for example, the valve disc supported by the fluid damper can move smoothly during normal operation, that is, open and close the valve disc at a speed lower than the switching speed.

[0024] The valve disc has a central region extending radially outward from the stroke axis, and this central region has no through holes. In this way, independent of the valve disc's position relative to the piston base, and given the large, holeless surface along the stroke axis to which the positive pressure in the front or rear space can act, a large force can be applied in the central region to move the valve disc, independent of its position. Therefore, a particularly reliable and precise switching characteristic between the open and closed positions of the valve disc is achieved, independent of potential frictional forces on the valve disc. Attached Figure Description

[0025] Further advantages, objects, and features of the invention are set forth in the following description and accompanying drawings, wherein the subject matter of the invention is illustrated by way of example. Features that at least substantially correspond to each other in the figures are indicated herein by the same reference numerals, although these features are not necessarily provided with reference numerals and are explained in all the figures.

[0026] Figure 1 A schematic longitudinal cross-sectional view along the stroke axis of a fluid damper according to one embodiment is shown.

[0027] Figure 2 A schematic longitudinal cross-sectional view along the stroke axis of a switching piston in the open position of a fluid damper according to one embodiment is shown.

[0028] Figure 3A schematic longitudinal cross-sectional view along the stroke axis of the switching piston in the closed position of a fluid damper according to another embodiment is shown.

[0029] Figure 4 A schematic longitudinal cross-sectional view along the stroke axis of the switching piston in the closed position of a fluid damper according to another embodiment is shown.

[0030] Figure 5 A schematic plan view along the stroke axis of the switching piston of a fluid damper according to another embodiment is shown. Detailed Implementation

[0031] The central region without through holes preferably extends outward from the stroke axis to a central region radius, which is equivalent to 50% to 100% of the valve disc radius radially along the stroke axis, preferably 75% to 98%, and particularly preferably 85% to 95%. In experiments, the above-mentioned indicated value of the central region radius resulted in particularly reliable valve disc switching characteristics.

[0032] Preferably, the valve disc has a plurality of, for example, one, two, three, four, five, or more annular through-holes for allowing damping fluid to pass along the stroke axis through the outside of the central region of the valve disc. The through-holes preferably open radially outward from the stroke axis. The through-holes define a throttling cross-section for the damping fluid. By changing the cross-sectional area and / or the number of through-holes, the throttling cross-section can be adjusted, and thus the damping force of the fluid damper can be adjusted. The throttling cross-section can be adjusted in a particularly simple and tolerant manner by changing the width of the bridge between the through-holes measured in the circumferential direction around the stroke axis.

[0033] Bridges between the through-holes can be used to guide the valve disc on the piston base and / or guides. Advantageously, the bridges allow the valve disc to be aligned along the stroke axis without increasing the risk of misalignment on the piston base and / or guides. Particularly preferred is that the valve disc has three outwardly opening through-holes. In this way, three bridges are obtained between the through-holes for guiding the valve disc on the piston base and / or guides.

[0034] The fluid damper preferably includes a guide fixed to the piston base and disposed between the valve disc and the cylinder housing wall, the guide movably guiding the valve disc between an open and closed position along the stroke axis. The guide prevents contact between the valve disc and the cylinder, which could affect the switching characteristics of the valve disc.

[0035] The guide element is preferably constructed as a guide sleeve and / or arranged coaxially with the stroke axis. The guide element can be connected to the piston base by friction, by complementary shapes, by chemical adhesive, and / or integral molding. Preferably, the guide element and the piston base are connected by complementary shapes and / or integral molding, thereby ensuring simple manufacturing and reliable connection.

[0036] The fluid damper may include a support for supporting the guide member on the piston body. As an example, the support member is connected to the piston body and the guide member by a latching connection and / or complementary shapes.

[0037] Preferably, the valve disc is guided individually by a guide member. In this way, the frictional force acting on the valve disc is minimized, thereby achieving particularly precise switching characteristics.

[0038] The fluid damper preferably includes at least one stop attached to the piston base, which restricts the movement of the valve disc relative to the piston base in the opening direction from a closed position to an open position. The stop may be integrally formed with the piston base and / or guide members. Advantageously, by means of the stop, a well-defined throttling cross-section for damping the fluid is obtained in the open position. In this way, when the valve disc is in the open position, the fluid damper has an appropriately set damping force during normal operation.

[0039] The stop preferably includes a plurality of protrusions, such as one, two, three, four, five or more, to reduce the contact surface between the stop and the valve disc. As an example, the protrusions are hemispherical or conical to obtain a minimal, particularly point-shaped, contact surface between the protrusion and the valve disc. In this way, the flow surface of the valve disc used to dampen the fluid is kept as constant as possible during valve disc movement. A constant flow surface results in precise switching operation with low tolerance sensitivity.

[0040] The fluid damper preferably includes a spring element disposed between the valve disc and the piston base, used to push the valve disc to the open position along the stroke axis. When the positive pressure of the front space relative to the rear space exceeds the switching pressure, the valve disc can preferably move from the open position to the closed position in reverse direction of the spring element under the action of the positive pressure. As an example, the spring element is a mechanical spring, especially a helical compression spring.

[0041] Preferably, when the positive pressure in the front space does not exceed the switching pressure, the spring ensures that the valve disc is in the open position. In this way, at any time during normal operation, when the piston base moves at a speed lower than the switching speed in the sliding-in or sliding-out direction, the fluid damper has a low damping force.

[0042] Preferably, the spring is disposed in a groove in the piston body, for example, in an inner bore coaxial with the stroke axis in the piston body. This groove arrangement prevents contact between the spring and the cylinder, which could affect the switching characteristics of the valve disc.

[0043] Preferably, the groove where the spring element is arranged has a diameter smaller than that of the valve disc transverse to the stroke axis, such that the edge of the groove forms a clearly defined valve seat for the valve disc in the closed position.

[0044] The groove containing the spring can form part of a channel. From the groove, another part of the channel can extend through the piston body, for example, axially or radially to the stroke axis.

[0045] Fluid dampers are characterized by more precisely matched switching characteristics, such as precisely matched switching speeds, and the ability to decouple switching characteristics from frictional effects, i.e., the valve disc must move independently against the spring force of the spring member.

[0046] The valve disc can deform, particularly elastically, in the closed position by the positive pressure in the front space relative to the rear space, which causes the valve disc to open at least one passage when the positive pressure exceeds the override pressure. The override pressure can be a pressure higher than the expected operating pressure during use. In this way, damage to the fluid damper, especially the valve disc, due to excessive positive pressure caused by, for example, malfunction of the fluid damper, is prevented. Alternatively, protection against excessive positive pressure can be provided, for example, by a pre-set leakage, especially on the sealing surface between the valve disc and the piston base, and / or by connecting an additional bypass for the damping fluid from the front space to the rear space.

[0047] Preferably, the valve disc is rigid, and more preferably, it does not have a central through-hole, central bore, or central bypass. In this way, particularly reliable and predictable valve disc switching characteristics are obtained.

[0048] The valve disc preferably comprises or is made of plastic material. The valve disc is preferably obtained by injection molding. A lighter valve disc, with a shape different from a simple disc, can be manufactured at low cost using plastic material, preferably by injection molding. A smaller valve disc mass is advantageous because it allows for easier movement, resulting in precise switching characteristics.

[0049] The fluid damper preferably includes a seal, such as a sealing ring, disposed between the valve disc and the piston base, particularly an O-ring that seals the valve disc and the piston base in a fluid-tight manner in the closed position.

[0050] In a particularly preferred embodiment, for the sake of simplified manufacturing, no separate seal is provided between the valve disc and the piston base; instead, the valve disc rests directly against the piston base in the closed position. Sufficient sealing can be achieved, for example, through a suitable material for the valve disc, particularly a material softer than the piston base, preferably plastic, and / or through a coating on the valve disc and / or the piston base.

[0051] The contact surface between the valve disc and the piston base is preferably annular to achieve a particularly simple design and predictable switching characteristics for the switching piston.

[0052] The fluid damper preferably includes a piston rod attached to a piston base. The piston rod is preferably fixed to the piston base by forming, and the piston base is radially arranged to segmentally surround the piston rod along the stroke axis, and is fixed to the piston rod by forming towards the stroke axis, particularly in grooves within the piston rod. Compared to other fixing methods, such as riveting the piston base to the piston rod along the stroke axis, forming towards the stroke axis has the advantage of not applying force to the valve disc, thus ensuring that the valve disc's switching function remains unaffected.

[0053] The piston base can be fixed to the piston rod by riveting. The complexity of riveting is preferably reduced by directly riveting the piston base to the piston rod as a single piece.

[0054] The connection between the piston base and the piston rod is preferably located outside the movement range of the valve disc, so as to avoid the switching function of the valve disc being affected by its connection.

[0055] The piston rod and / or piston body are preferably made of aluminum and / or steel.

[0056] The fluid damper preferably includes at least one corresponding connector, such as a ball seat, on the cylinder and piston rod respectively, to mechanically connect the fluid damper to other components, such as valve discs and vehicle chassis.

[0057] The fluid damper preferably includes a seal attached to the piston base, preferably surrounding the stroke axis, such as a sealing ring, especially an O-ring, to fluid-tightly seal the piston base to the cylinder. Advantageously, the seal ensures that the damping fluid does not flow from the front space to the rear space or vice versa between the piston base and the housing wall. Therefore, the damping characteristics of the fluid damper depend solely on the flow resistance of the damping fluid in the channel.

[0058] The method for manufacturing a fluid damper preferably includes at least forming a piston base of the fluid damper on the stroke axis of the fluid damper to fix the piston base to the piston rod of the fluid damper. This allows the advantages of the aforementioned forming process to be achieved.

[0059] The method preferably involves obtaining the valve disc of the fluid damper using injection molding or precision stamping. Advantageously, using this method, valve disc shapes different from simple discs, such as discs with through holes and / or protrusions, can be manufactured cost-effectively.

[0060] This invention relates to a valve disc actuation device for a motor vehicle, comprising at least one motor drive for moving the valve disc and at least one fluid damper according to the invention for supporting the valve disc. The fluid damper is preferably configured as a pneumatic spring, wherein the pneumatic spring may be integrated into the suspension strut.

[0061] Preferably, the fluid damper is configured such that the valve disc is in the open position during normal operation of the drive device, thereby enabling the fluid damper to have a low damping force and a motorized drive device that can move the valve disc with low energy consumption.

[0062] Preferably, the fluid damper is configured such that, in an emergency, the valve disc moves from the open position to the closed position, such as in the event of disengagement of the motor drive or power loss, the pressure of the damping fluid damper increases, and the valve disc is reduced in a controlled manner.

[0063] Figure 1

[0064] Figure 1 A schematic longitudinal cross-sectional view along the stroke axis H of a fluid damper 100 according to one embodiment is shown.

[0065] The fluid damper 100 includes a cylinder 110 filled with a damping fluid (not shown), such as a gas with positive pressure, a piston base 120 movably guided in the cylinder 110 along the stroke axis H, and a valve disc 130 spaced apart from the housing wall 113 of the cylinder 110.

[0066] The piston base 120 divides the internal space of the cylinder 110 into a front space 111 and a rear space 112 along the stroke axis H, and at least one channel (not shown) for fluid conduction connection between the front space 111 and the rear space 112 is arranged in the piston base 120.

[0067] The fluid damper 100 includes a seal 122 attached to the piston base 120 and surrounding the stroke axis H, which fluid-tightly seals the piston base 120 to the housing wall 113 of the cylinder 110.

[0068] The valve disc 130 is movably guided relative to the piston base 120 along the stroke axis H between an open position that releases the blockage of at least one channel 121 and a closed position that closes the blockage of at least one channel 121.

[0069] The fluid damper 100 includes a spring 150, such as a helical compression spring, disposed between the valve disc 130 and the piston base 120. The spring 150 is used to push the valve disc 130 to the open position H along the stroke axis. When the positive pressure of the front space 111 relative to the rear space 112 exceeds the switching pressure, the valve disc 130 can move from the open position to the closed position in the opposite direction of the spring 150.

[0070] The spring element 150 is disposed in the groove 123 of the piston base 120, for example, disposed in the inner bore coaxial with the stroke axis H.

[0071] The fluid damper 100 includes a piston rod 170 fixed to the piston base 120, which extends out of the cylinder 110 through the rear space 112.

[0072] On the end of the piston rod 170 not attached to the piston base 120 and on the end of the cylinder 110 not leading the piston rod 170 out of the cylinder 110, respectively, corresponding connectors 180, such as ball seats, are installed, which are arranged to mechanically connect the fluid damper 100 to other components, such as valves and chassis of the vehicle.

[0073] Figure 2

[0074] Figure 2 A schematic longitudinal cross-sectional view along the stroke axis of a switching piston in the open position of a fluid damper 100 according to one embodiment is shown. Figure 1 The components already shown are made of and Figure 1 The same reference numerals are used in the accompanying drawings and will not be described again.

[0075] exist Figure 2 A channel 121 in the piston body 120 is shown to fluidly connect the front space 111 to the rear space 112. The channel 121 includes, for example, an inner bore radially disposed along the stroke axis H, which fluidly connects the groove 123, in which the spring member 150 is disposed, to the rear space 112.

[0076] Figure 2 The fluid damper 100 shown includes a guide member 140 fixed to the piston base 120 and arranged between the valve disc 130 and the housing wall 113 of the cylinder 110, such as a guide sleeve H coaxial with the stroke axis. The guide member 140 is positioned along the stroke axis H as shown in the image. Figure 2 The valve disc 130 is movably guided between the open and closed positions shown.

[0077] The guide 140 includes a stop 141, such as a protrusion oriented about and toward the stroke axis H, which is used to limit the mobility of the valve disc 130 relative to the piston base 120 in the opening direction from the closed position to the open position.

[0078] exist Figure 2 In the illustrated embodiment, the piston base 120 segments around the piston rod 170, which is radially disposed along the stroke axis H. The piston base 120 is fixed in a groove 171 on the piston rod 170 by being shaped toward the stroke axis H.

[0079] Figure 3

[0080] Figure 3 A schematic longitudinal cross-sectional view along the stroke axis H of the switching piston of the fluid damper 100 in the closed position according to another embodiment is shown. Figure 1 or Figure 2 The components shown are indicated by the same reference numerals provided therein and will not be described again.

[0081] Figure 3 The fluid damper 100 shown includes a support 190 for supporting the guide 140 on the piston base 120. The support 190 is connected to the piston base 120 by, for example, a latching connection, and is connected to the guide 140 in a complementary shape to the guide 140.

[0082] Figure 4

[0083] Figure 4 A schematic longitudinal cross-sectional view along the stroke axis of the switching piston of the fluid damper 100 in the closed position according to another embodiment is shown. Figure 1 , 2 The components shown in or 3 are indicated by the same reference numerals provided therein and will not be described again.

[0084] exist Figure 4 In the illustrated embodiment, the stop 141 for the valve disc 130 includes a plurality of, for example, three, protrusions 142 for reducing the contact surface between the stop 141 and the valve disc 130. The protrusions 142 are, for example, hemispherical.

[0085] Figure 5

[0086] Figure 5 A schematic plan view of the switching piston of a fluid damper 100 according to another embodiment is shown along the stroke axis H. Figure 1 , 2 Components shown in 3 or 4 are indicated by the same reference numerals provided thereon and will not be described again.

[0087] exist Figure 5 In the middle, the valve disc 130 has a central region 131 extending radially outward from the stroke axis H, and the central region 131 is formed without through holes, that is, there are no through holes along the stroke axis H.

[0088] On the periphery of central area 131, Figure 5 The valve disc 130 shown has a plurality of through holes, such as three through holes 132, for allowing damping fluid to pass through the valve disc 130 along the stroke axis H. The through holes 132 are, for example, annular and open radially outward from the stroke axis H.

[0089] Between adjacent through holes 132, corresponding bridges 133 are arranged, which can be used to guide the valve disc 130 on the guide member 140.

[0090] List of reference numerals

[0091] 100 Fluid damper

[0092] 110 cylinder

[0093] 111 Front Space

[0094] 112 Rear Space

[0095] 113 Shell wall

[0096] 120 Piston Base

[0097] Channel 121

[0098] 122 Seals

[0099] 123 Groove

[0100] 130 Valve Disc

[0101] 131 Central Area

[0102] 132 Through Hole

[0103] 140 guide component

[0104] 141 Stopping component

[0105] 142 protrusions

[0106] 150 Spring Components

[0107] 160 seal

[0108] 170 Piston Rod

[0109] 171 Trench

[0110] 180 connector

[0111] 190 Support Component

[0112] H travel axis

Claims

1. A fluid damper (100), comprising: a. A cylinder (110) filled with damping fluid, b. A piston base (120) movably guided along the stroke axis (H) in the cylinder (110), and c. A valve disc (130) spaced apart from the housing wall (113) of the cylinder (110). d. The piston base (120) divides the internal space of the cylinder (110) into a front space (111) and a rear space (112) along the stroke axis (H). e. At least one channel (121) in the piston body (120) that fluidly connects the front space (111) and the rear space (112). f. The valve disc (130) is movably guided relative to the piston base (120) along the stroke axis (H) between an open position and a closed position, wherein in the open position the valve disc (130) unblocks the at least one channel (121) and in the closed position the valve disc (130) closes the at least one channel (121). g. The valve disc (130) has a central region (131) extending radially outward from the stroke axis (H), the central region (131) having no through holes. h. The fluid damper (100) includes a stop (141) attached to the piston base (120) for limiting the movement of the valve disc (130) relative to the piston base (120) in the opening direction from the closed position to the open position. i. The stop (141) includes a plurality of hemispherical or conical protrusions (142) for reducing the contact surface between the stop (141) and the valve disc (130). j. The valve disc (130) has a plurality of through holes (132) for allowing damping fluid to pass through the valve disc (130) along the stroke axis (H) outside the central region (131). Its features are, k. The plurality of through holes (132) are annular and / or open radially outward from the travel axis (H).

2. The fluid damper (100) of claim 1, wherein, The central region (131) without through holes extends outward from the stroke axis (H) to the central region radius (ZR), which is 50% to 100% of the valve disc radius (VR) of the valve disc (130) radially along the stroke axis (H).

3. The fluid damper (100) of claim 1, wherein, A guide (140) is fixed to the piston base (120) and arranged between the valve disc (130) and the housing wall (113) of the cylinder (110). The guide (140) movably guides the valve disc (130) between the open and closed positions along the stroke axis (H).

4. The fluid damper (100) according to claim 1, characterized in that, The fluid damper (100) includes a spring (150) disposed between the valve disc (130) and the piston base (120) for pushing the valve disc (130) to the open position along the stroke axis (H). When the positive pressure of the front space (111) relative to the rear space (112) exceeds the switching pressure, the valve disc (130) can move from the open position to the closed position in reverse direction of the spring (150) under the action of the positive pressure.

5. The fluid damper (100) according to claim 4, characterized in that, The spring (150) is disposed in the groove (123) of the piston base (120).

6. The fluid damper (100) according to claim 5, characterized in that, The diameter of the groove (123) is smaller than the diameter of the valve disc (130) which is transverse to the stroke axis (H).

7. The fluid damper (100) according to claim 1, characterized in that, In the closed position, the valve disc (130) can elastically deform in the front space (111) relative to the rear space (112) under the action of a positive pressure, such that when the positive pressure exceeds the overdrive pressure, the valve disc (130) opens the at least one channel (121).

8. The fluid damper (100) according to claim 1, characterized in that, The valve disc (130) directly abuts against the piston base (120) in the closed position, and the contact surface between the valve disc (130) and the piston base (120) is annular.

9. The fluid damper (100) according to claim 1, characterized in that, The fluid damper (100) includes a piston rod (170) fixed to the piston base (120), the piston base (120) being radially segmented around the piston rod (170) along the stroke axis (H) and the piston base (120) being fixed to the piston rod (170) by shaping the piston base (120) toward the stroke axis (H).

10. The method for manufacturing the fluid damper (100) according to claim 9, characterized in that, The method includes the following steps: The piston base (120) of the fluid damper (100) is shaped toward the stroke axis (H) of the fluid damper (100) to fix the piston base (120) to the piston rod (170) of the fluid damper (100).

11. A valve disc drive device for a motor vehicle, comprising at least one motor drive device for moving the valve disc, characterized in that, The drive device includes at least one fluid damper (100) according to any one of claims 1 to 9 for supporting the valve disc.

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