Piston rod guide with throttle valve, valve pin replacement set and method for damping force adjustment

Abstract

Piston rod guide (12) for a vibration damper (1) which has a cylinder tube (2) and a container tube (3), wherein the cylinder tube (2) is arranged coaxially in the container tube (3) forming a compensating chamber (7), wherein a piston (5) is arranged axially displaceable in the cylinder tube (2) via a piston rod (4) and the cylinder tube (2) is divided into two working chambers (6a, b), with a base body (14) which has a cylinder tube receptacle (17) for receiving the cylinder tube (2), a central guide opening (18) for axial guidance of the piston rod (4) and several return channels (27), with a sealing unit (15) which has a piston rod seal (19) for sealing the piston rod (4), wherein a collecting space (26) for a damper fluid is formed between the piston rod seal (19) and the base body (14), which is fluidically connected to the compensation chamber (7) via the return channels (27), characterized by the fact that the piston rod guide (12) has at least one throttle valve (16) for influencing a damping force of the vibration damper (1), wherein the throttle valve (16) is formed by a valve opening (28) provided in the base body (14), which fluidly connects a piston rod-side working chamber (6a) with the collecting chamber (26) and / or at least one of the return channels (27), and a valve pin (29) inserted into the valve opening (28), which closes the valve opening (28) in a closed position (104) and at least partially releases it in an open position (103).

Description

[0001] The invention relates to a piston rod guide for a vibration damper having the features of the preamble of claim 1. Furthermore, the invention relates to a valve pin change with the piston rod guide and a method for adjusting the damping force of a vibration damper with the piston rod guide and / or the valve pin change set.

[0002] Vibration dampers are known which essentially comprise a working cylinder filled with a damping medium and at least one piston arranged axially displaceably within the working cylinder and secured to a piston rod. The piston rod is sealingly guided into the working cylinder via a piston rod guide, with the piston rod guide simultaneously sealing the working cylinder. Such vibration dampers also have at least one damping valve, which is designed as a piston or base valve arranged on the piston. The damping valve has a valve body with several passages, which are covered on at least one side by at least one resilient valve disc in order to throttle a volume flow of the damping medium through the damping valve.The damping valve also features so-called pre-openings, which are permanently open and allow a constant volume flow of the damping medium through the damping valve, especially at lower piston speeds. These pre-openings are formed in so-called pre-opening discs, which are taken into account during damper design and integrated into the valve assembly. The pre-opening discs can only be adjusted with considerable effort once the vibration damper is installed.

[0003] The publication DE 10 2017 206 824 A1 describes a sealing and guide arrangement for a vibration damper having a fluid-filled pressure cylinder tube, which is concentrically enclosed at a radial distance by a container tube to form an annular container space. A piston is axially displaceably arranged in the pressure cylinder tube, which divides the pressure cylinder tube into two working chambers and has a piston rod on one side, which extends out of the pressure cylinder tube and the container tube through a guide opening of a piston rod guide and an annular piston rod seal. The piston rod guide closes the pressure cylinder tube, and the container tube has a radially circumferential bearing surface on which a reinforcing ring disk of the piston rod seal is axially supported with its radially outer circumferential annular region.The free end of the container tube is deformed radially inward, encompassing the outward-facing end faces of the piston rod guide and piston rod seal. The piston rod seal, on its end face facing away from the interior of the container tube, has a radially circumferential tool contact surface radially within the radially circumferential support surface. The piston rod guide has one or more support elements against which the reinforcing ring disk of the piston rod seal rests axially opposite the tool contact surface.

[0004] US Pat. No. 9,879,748 B2 discloses a piston rod guide for a vibration damper, which comprises a cylinder tube and a reservoir tube. The cylinder tube is arranged coaxially within a reservoir tube to form a compensation chamber. A piston is arranged axially displaceably in the cylinder tube via a piston rod, which divides the cylinder tube into two working chambers. A piston rod guide has a throttle valve for influencing the damping force of a vibration damper, as well as a valve pin inserted into a valve opening, which closes a valve opening in a closed position and partially releases it in an open position. The disadvantage here is that the piston rod guide has a complex structure and consists of several components, with one of the components containing a separate and adjustable valve element to influence the damping force.

[0005] US 2014 / 0 090 941 A1 discloses another piston rod guide for a vibration damper, which has a cylinder tube and a container tube, wherein the cylinder tube is arranged coaxially in the container tube to form a compensation chamber. A piston is arranged in the cylinder tube so as to be axially displaceable via a piston rod and divides the cylinder tube into two working chambers. A base body has a cylinder tube receptacle for receiving the cylinder tube, a central guide opening for axially guiding the piston rod, and several return flow channels. An additional seal-guide unit, which has a piston rod seal for sealing the piston rod and axially guides the piston rod.The seal guide unit further comprises a throttle valve formed by a valve disc for influencing a damping force of the vibration damper, wherein the throttle valve has a valve opening introduced into the base body, which fluidically connects the piston rod-side working chamber to a collecting chamber.

[0006] The object of the invention is to create a piston rod guide of the type mentioned at the outset, which is characterized by a simple and cost-effective influencing of the damping force in the assembled state of the vibration damper.

[0007] This object is achieved according to the invention by a piston rod guide having the features of claim 1, a valve pin replacement set having the features of claim 10, and by a method having the features of claim 13. Advantageous embodiments emerge from the subclaims, the drawings, and / or the description.

[0008] The invention relates to a piston rod guide that is designed and / or suitable for a vibration damper. The vibration damper is preferably designed as a hydraulic damper. Specifically, the vibration damper is designed and / or suitable for a vehicle, in particular a chassis of the vehicle. The vibration damper is particularly preferably designed as a twin-tube damper.

[0009] The vibration damper comprises a cylinder tube and a container tube, wherein the cylinder tube is arranged coaxially, particularly with respect to a longitudinal axis of the vibration damper, in the container tube, forming a compensation chamber. Preferably, the compensation chamber is formed between the cylinder tube and the container tube by a radial clearance or an annular space.

[0010] The vibration damper comprises a piston which is arranged axially displaceably in the cylinder tube via a piston rod and divides the cylinder tube into two working chambers. The piston is preferably mounted on the end of the piston rod and / or coupled to it for movement. The piston preferably has a piston valve for generating a damping force during a pulling and / or pushing movement of the piston. The piston rod is preferably guided by the piston rod guide, wherein the piston rod guide delimits and / or closes off the cylinder tube and / or the container tube in the axial direction.

[0011] The piston rod guide comprises a base body having a cylinder tube receptacle for receiving the cylinder tube, a central guide opening for axially guiding the piston rod, and a plurality of return channels. In particular, the base body is mounted on the cylinder tube in the axial direction relative to the longitudinal axis, at least by means of the cylinder tube receptacle, with the working chamber and the compensation chamber being fluid-tightly sealed from one another in the region of the cylinder tube receptacle. Furthermore, the container tube can interact with the piston rod guide in a form-fitting and / or force-fitting manner, for example by forming, such that the compensation chamber is fluid-tightly sealed from the environment and, at the same time, the piston rod guide is fixed in the axial direction.The central guide opening is preferably designed as an opening extending axially with respect to the longitudinal axis, preferably a bore, through which the piston rod is guided. The plurality of return channels are each formed by an opening, preferably a window, introduced radially with respect to the longitudinal axis, which extends radially from the guide opening toward an outer circumference of the base body. Particularly preferably, the return channels each open into the compensation chamber in a proper installation situation.

[0012] The piston rod guide has a sealing unit that includes a piston rod seal for sealing the piston rod. When installed as intended, the piston rod is guided by the piston rod seal, with the piston rod seal sealingly abutting the piston rod circumferentially with at least one sealing lip. In particular, the piston rod seal is arranged coaxially and / or concentrically with the base body, in particular the guide opening, with respect to the longitudinal axis. The piston rod seal preferably has a sealing section for sealing the piston rod and a fastening section for fastening and / or engaging the piston rod seal with the base body.

[0013] A collecting chamber for a damper fluid is formed between the piston rod seal and the base body, wherein the collecting chamber is fluidly connected to the compensation chamber via the return flow channels. In particular, the collecting chamber serves to collect damper fluid scraped off by the piston rod seal and to discharge it to the compensation chamber via the return flow channels. Preferably, the collecting chamber is designed as an annular chamber surrounding the longitudinal axis, in particular the piston rod, from which annular chamber the return flow channels extend radially outwards. In particular, the collecting chamber is delimited in a radial direction by the base body and in a radially opposite direction by the piston rod seal, in particular the sealing section. In particular, the collecting chamber is delimited in an axial direction by the base body and in an axially opposite direction by the piston rod seal, in particular the fastening section.

[0014] Within the scope of the invention, it is proposed that the piston rod guide has at least or precisely one throttle valve which is designed and / or suitable for influencing a damping force of the vibration damper. In particular, the at least one throttle valve serves for fine adjustment and / or readjustment of the damping force in the assembled state of the vibration damper and / or as part of a damping force test. The throttle valve is formed by a valve opening introduced into the base body and a valve pin inserted into the valve opening. Preferably, the valve pin influences the flow characteristic through the valve opening and thus the damping forces in at least one direction of movement of the piston rod. The valve opening is introduced into the base body in such a way that it fluidically connects a working chamber on the piston rod side with the collecting chamber and / or at least one of the return flow channels.Preferably, the valve opening is formed in the base body between the cylinder tube receptacle and the guide opening. The valve pin is inserted into the valve opening such that it closes the valve opening in a closed position and at least partially releases the valve opening in an open position. In particular, upon actuation, in particular during a pulling and / or pushing movement, the valve pin can be moved automatically from the closed position to the open position or from the open position to the closed position. Particularly preferably, the valve pin is inserted into the valve opening in a removable and / or dismantled manner, preferably by being inserted.

[0015] The invention is based on the finding that approximately 1-2% of vibration dampers exhibit a damping force deviation during damping force testing that exceeds the required tolerances. If damping force deviations exceed the tolerances occur, the entire vibration damper must be disassembled to replace the corresponding pre-opening disc. Therefore, cost-effective and modular solutions that can be installed quickly and easily in production are needed.

[0016] A piston rod guide is therefore proposed which, by selecting suitable valve openings and corresponding valve pins, enables the damping forces to be adjusted simply and cost-effectively via the piston rod guide. This has the advantage that the damping forces can be subsequently adjusted via the piston rod guide while the vibration damper is still assembled. If, for example, deviations exceeding tolerances occur during a damping force test, the entire vibration damper no longer needs to be disassembled in order to replace the corresponding valve discs, especially the pre-opening discs, to adjust the damping force. This provides a simple solution to the problem of damping force deviations in the pre-opening range of vibration dampers.

[0017] In a specific embodiment, the throttle valve is designed to influence the damping force during a pulling movement of the piston rod by allowing fluid to flow from the working chamber on the piston rod side into the compensation chamber and blocking flow in the opposite direction. In simplified terms, the throttle valve is thus designed as a check valve that permits fluid to flow in only one direction. In particular, the valve pin can be moved automatically from the closed position to the open position during the pulling movement of the piston rod and from the open position to the closed position during the pushing movement of the piston rod. The valve pin is preferably designed to seal the valve opening in the closed position.Thus, the damping forces in the pre-opening range of the rebound stage are primarily influenced, whereas the influence on the damping forces of the compression stage is small compared to a classic piston rod guide.

[0018] In a further specific embodiment, the valve pin can be replaced by a shuttle valve pin of a valve pin replacement set for fine adjustment of the damping force, wherein the valve pin and the shuttle valve pin have at least one different pin diameter. In particular, by changing the pin diameter, the flow resistance through the throttle valve in the open position of the valve pin can be changed in order to adjust the damping force. In particular, a maximum difference between the pin diameter of the valve pin and the shuttle valve pin is more than 0.05 mm, preferably more than 0.1 mm, in particular more than 0.5 mm. Thus, a throttle valve is proposed which enables variable adjustability of the damping force in a simple manner by replacing the valve pin.Thus, a multi-stage adjustment of the damping force of the vibration damper in the assembled state can be ensured in a particularly simple and cost-effective manner by selecting different valve pins.

[0019] In a further embodiment, the valve opening opens into one of the return flow channels, so that the working chamber on the piston rod side is fluidically connected to the return flow channel via the valve opening. Preferably, the return flow channels are open to the outside in the axially opposite direction or on a side facing away from the working chamber, wherein the valve pin, preferably when the sealing unit is disassembled, can be inserted into or removed from the outside via the return flow channels into the valve opening. In particular, the valve opening extends from the return flow channel in the axial direction with respect to the longitudinal axis through the base body. The arrangement of the throttle valve in one of the return flow channels thus ensures, on the one hand, that the throttle valve or the valve pin is easily accessible from the outside.On the other hand, a collision of the valve pin with the piston rod seal, especially with the sealing section, is prevented, thus ensuring the functional reliability of the vibration damper.

[0020] In a further specific embodiment, it is provided that the valve opening is designed as a stepped bore with different bore diameters. In particular, a first bore section adjacent to the piston rod-side working chamber has a smaller bore diameter than a second bore section adjacent to the collecting chamber or the return flow channel. In particular, a difference between the bore diameters of the first and second bore sections is more than 0.5 mm, preferably more than 1 mm, in particular more than 1.5 mm. Alternatively or optionally additionally, the bore diameter of the first bore section is at least or exactly 50%, preferably at least or exactly 40%, in particular at least or exactly 30%, of the bore diameter of the second bore section. Alternatively, the valve opening is designed as a through-bore with a constant bore diameter.In particular, the stepped bore, in particular the second bore diameter, or the through-bore, has a maximum bore diameter of at least or exactly 1.5 mm, in particular at least or exactly 2 mm. Particularly preferably, the valve pin is inserted in the axial direction into the stepped bore, preferably the second bore section, or the through-bore. Thus, a valve opening is proposed that is characterized by a particularly simple structural design.

[0021] In a further embodiment, the valve pin has a valve sealing surface that interacts with a valve seat surface of the valve opening. The valve seat surface of the valve opening is formed either on an upper side of the base body facing the collecting chamber or on a cylinder shoulder. Preferably, the valve seat surface is formed on the upper side of the base body if the valve opening is designed as a through-bore. Alternatively, the valve seat surface is formed on the cylinder shoulder if the valve opening is designed as a stepped bore. The cylinder shoulder is formed between the first and second bore sections due to the changed bore diameter.In particular, the valve sealing surface and the valve seat surface are designed as two complementary surfaces which, in the closed position of the valve pin, contact one another linearly and / or flatly, preferably over their entire surface. For example, the valve sealing surface and the valve seat surface extend flatly, in particular in a separate radial plane with respect to the longitudinal axis. Alternatively, however, the valve seat surface and the valve sealing surface can also be inclined, in particular conically, or curved. Alternatively, however, it can also be provided that at least the shuttle valve pin has a different valve sealing surface than the valve pin. Thus, a throttle valve is proposed which is characterized by a simple and cost-effective design.Optionally, a valve pin is proposed which, through a suitable selection of the valve sealing surface, causes an additional change in the flow characteristics of the valve opening.

[0022] In a further development, the valve sealing surface is located at the end of the valve pin. In the simplest embodiment, the valve pin can be designed as a cylindrical pin, with the valve sealing surface being located at the end of the cylindrical pin. In particular, the valve opening is designed as a stepped bore, with the cylindrical shoulder preventing the valve pin from falling through the valve opening and simultaneously forming the valve seat. Thus, a throttle valve is proposed which is characterized by a particularly simple and cost-effective design of the valve pin.

[0023] Alternatively, the valve pin has a valve pin head, wherein the valve sealing surface is formed on the valve pin head. Preferably, the valve sealing surface formed on the valve pin head is formed by a circumferential collar or annular shoulder. In particular, the valve opening is designed as the through-bore, wherein the valve pin head prevents the valve pin from falling through the valve opening. Preferably, the valve pin head has a larger diameter than the valve opening. In particular, the valve pin is designed in the shape of a nail. Thus, a throttle valve is proposed which is characterized by a particularly simple and cost-effective design of the valve opening. In addition, the valve pin head can improve the handling of the valve pins.

[0024] In a further design embodiment, the sealing unit comprises a reinforcing disk which is designed and / or suitable for reinforcing the piston rod seal, in particular the fastening section. The reinforcing disk defines an end stop for the valve pin in the open position. In particular, the valve pin is freely movable in the axial direction with respect to the longitudinal axis between the reinforcing disk and the valve seat surface of the valve opening. In other words, the valve seat surface and the reinforcing disk each form an end stop for the valve pin in the axial direction. In particular, the reinforcing disk is supported in the axial direction on a support surface of the base body and in the radial direction with an outer circumference on a circumferential annular region of the base body.Particularly preferably, the reinforcement disc and the piston rod seal are connected to one another in a form-fitting and / or force-fitting and / or material-fitting manner, in particular to form a jointly manageable unit. Thus, a piston rod guide is proposed that is characterized by a compact yet robust design. Furthermore, the throttle valve, in particular the valve pin, can be designed particularly simply and cost-effectively, since the required end stops are defined by the surrounding geometry.

[0025] In a further development, it is provided that the piston rod guide has at least or exactly one further throttle valve. In particular, the throttle valve and the further throttle valve are of identical construction. For this purpose, the further throttle valve is formed by a further valve opening introduced into the base body and a further valve pin inserted into the further valve opening. The throttle valves are preferably arranged on a common pitch circle and / or evenly spaced from one another around the longitudinal axis or the guide opening. In principle, the valve opening and the further valve opening can be of identical design. Alternatively, however, the valve opening and the further valve opening can also be designed differently, in particular with different bore diameters. It is particularly preferably provided that one of the valve openings opens into one of the return flow channels.Specifically, it is intended that at least one separate throttle valve is provided for each return flow channel. To adjust the damping force, the valve pins of the individual throttle valves can be independently replaced with a corresponding shuttle valve pin. A very narrow tolerance range for the valve openings and valve pins allows for very fine adjustment across various combinations.

[0026] A further subject matter of the invention relates to a valve pin replacement set with the piston rod guide, as already described above. The valve pin replacement set comprises at least one or exactly one shuttle valve pin, which has a different, preferably smaller, pin diameter than the valve pin. Preferably, the valve pin and the at least one shuttle valve pin are of identical construction, wherein the valve pin and the shuttle valve pin only differ from one another in their pin diameter. In a first assembly state, the valve pin is inserted into the valve opening, and in a second assembly state, the shuttle valve pin is inserted into the valve opening instead of the valve pin. Particularly preferably, the valve pin replacement set has more than two, preferably more than five, in particular more than ten shuttle valve pins, wherein the shuttle valve pins are freely interchangeable or can be replaced with one another.are interchangeable. In particular, all shuttle valve pins in a valve pin replacement set have a different pin diameter. Thus, a valve kit is proposed that allows for simple readjustment or fine-tuning of the damping force by selecting a suitable shuttle valve pin.

[0027] In a specific implementation, it is provided that the valve pin has at least approximately the same diameter as the valve opening and the shuttle valve pin has a smaller diameter than the valve opening. In particular, the valve pin is inserted into the valve opening with a transition fit or a slight clearance fit. Preferably, the minimum dimension of the valve opening is equal to the maximum dimension of the valve pin. Preferably, the shuttle valve pin is inserted into the valve opening with a clearance fit, wherein the minimum dimension of the valve opening is greater than a maximum dimension of the valve pin. In particular, the shuttle valve pins are inserted in the valve opening with a minimum clearance of more than 0.05 mm, preferably 0.1 mm, especially 0.2 mm. Thus, a valve pin replacement set is proposed in which the damping force can be easily adjusted by appropriately selecting the pin diameter.

[0028] In a further specific embodiment, it is provided that the valve pin replacement set has a plurality of shuttle valve pins that differ from one another in terms of pin diameter. In particular, the valve pin replacement set has more than two, preferably more than five, especially more than ten different shuttle valve pins. The different shuttle valve pins have a clearly distinguishable identification. In particular, the identification is implemented as a color and / or shape identification. For example, the color identification can be realized by anodizing and / or painting the valve pins in different colors. For example, the shape identification can be realized by a different shape of the valve pin heads. Alternatively, however, the different shuttle valve pins can also be provided with a number and / or letter identification.A valve pin replacement kit is therefore proposed which is characterized by a very good distinguishability of the different valve pins.

[0029] Another object of the invention relates to a method for adjusting the damping force of a vibration damper with the piston rod guide and / or the valve pin replacement set, as already described above, in which: a damping force test is carried out, wherein if an actual damping force deviates from a target damping force, change information is determined and, based on the change information, a valve pin of the at least one throttle valve is changed or replaced with a shuttle valve pin of the valve pin replacement set. For this purpose, precise (digital) information about the current configuration of the valves, in particular of the at least one throttle valve, must be recorded or stored prior to the damping force measurement. Preferably, at least one piece of information about the currently used valve pin of the throttle valve is recorded or stored.Based on the change information, it is therefore easy to communicate which change needs to be made to the throttle valve if the vibration damper is identified as not OK during the damping force test and is rejected.

[0030] In a concrete implementation, the changeover information is determined based on a difference value between the actual damping force and the target damping force, whereby at least one corresponding changeover valve pin is selected from the valve pin changeover set based on the changeover information. For example, the damping force deviation can be determined based on stored data (databases, simulations, etc.). In particular, corresponding changeover information is stored for each difference value or for a defined difference value range. This prevents the user from having to act at their own discretion and possibly not immediately selecting the ideal configuration. This prevents further loops and thus saves time, as the computer calculation is faster than manual calculation by the user. In a further refinement, the change information relating to the respective shuttle valve pin is displayed as a code uniquely assigned to each shuttle valve pin. In particular, the change information can be displayed or output as a color and / or shape code. Particularly preferably, the change information can be displayed via a display device, such as a screen display. Thus, a particularly easy-to-use adjustment of the damping force of the vibration damper is proposed.

[0031] Further features, advantages, and effects of the invention will become apparent from the following description of preferred embodiments of the invention. These show: Fig. 1 a sectional view of a vibration damper along a longitudinal axis; Fig. 2 a detailed view of the vibration damper from Fig. 1; Fig. 3 a valve pin replacement set with several different change valve pins; Fig. 4 several different valve pin heads of the shuttle valve pins; Fig. 5 a basic body of a piston rod guide for the vibration damper in a sectional view; Fig. 6 the basic body in the same representation as Fig. 5 in an alternative version.

[0032] Fig. 1 shows a sectional view of a vibration damper 1, which is designed and / or suitable, for example, for damping vibrations in a chassis of a vehicle, as an embodiment of the invention.

[0033] In the illustrated embodiment, the vibration damper 1 is designed as a two-tube damper with a cylinder tube 2 and a reservoir tube 3, wherein the cylinder tube 2 is arranged coaxially in the reservoir tube 3 with a radial spacing relative to a longitudinal axis 100. The cylinder tube 2 and the reservoir tube 3 are at least partially filled with a damper fluid, e.g., hydraulic oil.

[0034] The vibration damper 1 has a piston rod 4 and a piston 5 fastened to the end of the piston rod 4, which is guided on an inner wall of the cylinder tube 2. The piston rod 4 and the piston 5 are movable within the cylinder tube 2 in the axial direction with respect to the longitudinal axis 100 in a tensile direction 101 and a compressive direction 102. The piston 5 divides an interior of the cylinder tube 2 into a first working chamber 6a on the piston rod side and a second working chamber 6b remote from the piston rod. A compensation chamber 7 is formed between the outer circumference of the cylinder tube 2 and the outer circumference of the container tube 3, which is hydraulically connected to the second working chamber 6b via a bottom valve 8. The volume change in the interior of the cylinder tube 2 caused by the piston rod 4 is primarily compensated via the compensation chamber 7.

[0035] The first and second working chambers 6a, 6b are hydraulically connected to one another via a rebound valve 9 integrated into the piston 5 and a compression valve 10. The damping characteristics of the vibration damper 1 in the rebound and compression stages are adjusted via the opening behavior of the piston valves 9, 10 in conjunction with the base valve 8. In this case, rebound stage is understood to be a state in which the piston rod 4 with the piston 5 is moved out of the cylinder tube 2 in the rebound direction 101. The pressure in the first working chamber 6a increases, while the pressure in the second working chamber 6b drops. The compression stage, on the other hand, is understood to be a state in which the piston rod 4 with the piston 5 is moved into the cylinder tube 2 in the compression direction 102. The pressure in the second working chamber 6b increases, while the pressure in the first working chamber 6a is lower.

[0036] The piston valves 9, 10 each have a pre-opening disc 11 with several pre-openings, not shown, which allow a constant passage for a further volume flow of the damping medium through the piston 5, wherein the further volume flow is defined by the cross section or by the size of the pre-openings and is smaller than the volume flow in the rebound or compression stage explained above.

[0037] To define the upper boundary of the first working chamber 6a and the compensation chamber 7, the cylinder tube 2 and the container tube 3 are closed by a piston rod guide 12, which is supported on an upper end of the cylinder tube 2. The piston rod 4 is guided coaxially to the longitudinal axis 100 through the piston rod guide 12. To define the lower boundary, the container tube 3 is closed at the end in the axial direction with respect to the longitudinal axis 100 by a damper base 13, wherein the lower second working chamber 6b is axially delimited by the base valve 8 attached to the lower end of the cylinder tube 2.

[0038] The piston rod guide 12 has a pot-shaped base body 14 and a sealing unit 15. The base body 14 is mounted on the upper end of the cylinder tube 2 in the axial direction with respect to the longitudinal axis 100, with the sealing unit 15 being arranged on a side of the base body 14 facing away from the cylinder tube 2 or the container tube 3. The piston rod 4 is guided axially with respect to the longitudinal axis 100 through the piston rod guide 12, in particular through the base body 14 and the sealing unit 15, with the sealing unit 1522 sealing the piston rod 4.

[0039] Furthermore, the piston rod guide 12 features a throttle valve 16, which is used for fine-tuning or readjusting the pre-openings in the event of a damping force deviation during a damping force test in production. The throttle valve 16 is adjustable in such a way that a multi-stage adjustment of the damping force is possible in the assembled state of the vibration damper 1 via the piston rod guide 12. This significantly reduces post-processing time.

[0040] Fig. 2 shows a detailed view of the vibration damper 1 from Fig. 1. The base body 14 has a cylinder receptacle 17, which serves to accommodate the upper end of the cylinder tube 2. For this purpose, the cylinder receptacle 17 is designed as a circumferential annular shoulder. Furthermore, the base body 14 has a central guide opening 18 through which the piston rod 4 is guided into the cylinder tube 2.

[0041] The sealing unit 15 has a piston rod seal 19 and a reinforcing disc 20, wherein the piston rod seal 19 is reinforced by the reinforcing disc 20. The piston rod seal 19 has an annular sealing section 21, which sealingly bears circumferentially against the piston rod 4 via at least two sealing lips 23, and a fastening section 22 radially adjoining the sealing section 21, which is connected to the base body 14, the container tube 3, and the reinforcing disc 20 in a form-fitting and / or force-fitting manner for fastening the piston rod seal 19.

[0042] The fastening section 22 is supported via the reinforcing disk 20 in the axial direction with respect to the longitudinal axis 100 on a support surface 24 and in the radial direction on an edge region 25 surrounding the support surface 24. The free end of the container tube 3, which initially projects axially beyond the base body 14, can be deformed radially inward after final assembly or after the damping force test, e.g., by rolling or flanging, so that the container tube 3 surrounds the base body 14 and the sealing unit 15 all the way around in order to fix them axially firmly to the support surface 24.

[0043] A collecting chamber 26 for the damper fluid is formed between the base body 14 and the sealing unit 15, the collecting chamber 26 being fluidly connected to the compensation chamber 7 via a plurality of return flow channels 27. The collecting chamber 26 serves to collect damper fluid scraped off by the sealing section 21, which can then flow into the compensation chamber 7 via the return flow channels 27. With respect to the longitudinal axis 100, the collecting chamber 26 is delimited in the axial direction on the one hand by the reinforcing disk 20 or the fastening section 22 and on the other hand by the base body 14, and in the radial direction on the one hand by the sealing section 21 and on the other hand by the base body 14. The collecting chamber 26 is to be understood as an annular space surrounding the longitudinal axis 100, into which the return flow channels 27 open.

[0044] The return flow channels 27 are to be understood as radially extending openings which are partially open axially outwards and are delimited by the sealing unit 15, in particular the reinforcing disc 20 and the fastening section 22.

[0045] The throttle valve 16 is formed by a valve opening 28 formed in the base body 14 and a valve pin 29 inserted into the valve opening 28. The valve opening 28 is arranged radially between the cylinder seat 17 and the guide opening 18 and extends axially through the base body 14. The valve opening 28 opens on one side into one of the return flow channels 27 and on the other side into the first working chamber 6a. Thus, the working chamber 6a and the collecting chamber 26 or the return flow channel 27 are fluidically connected to one another via the valve opening 28.

[0046] The valve pin 29 is inserted axially into the valve opening 28 via the return flow channel 27. In an operating state of the vibration damper 1, the valve pin 29 is automatically movable between an open position 103 and a closed position 104. In the open position 103, flow through the valve opening 28 is permitted and prevented in the closed position 104. When the piston rod 4 moves in the rebound direction 101, a volume flow thus flows from the first working chamber 6a via the throttle valve 16 and the return flow channels 27 into the compensation chamber 7, moving the valve pin 29 into the open position 103 and thus influencing the damping force of the rebound stage. The reinforcing disc 20 defines an axial end stop for the valve pin 29 in the open position 103.When the piston rod 4 moves in the compression direction 102, the valve pin 29 is moved into the closed position 104, preventing flow through the valve opening 28. During the compression stage, the valve pin 29 thus lowers and seals the valve opening 28 via a linear contact. This primarily influences the damping forces in the pre-opening range of the rebound stage. To adjust the damping force, the valve pin 29 is replaced by a change valve pin 31a-e, as shown in Fig. 3, a valve pin replacement set 30, wherein the shuttle valve pins 31a-e have different pin diameters d. The resulting changed opening cross-section acts as a throttle and influences the flow characteristics through the valve opening 28 and thus the damping forces. As part of the damping force test, the sealing unit 15 can be removed so that the valve pin 29 is accessible from the outside and the valve pin 29 can be easily removed. For example, the valve opening 28 has a maximum opening diameter of 1.5 mm or 2 mm. The shuttle valve pins 31a-b can, for example, have a diameter difference of 0.1 mm. For example, the valve pin 29 has a maximum pin diameter d of 1.5 mm or 2 mm, which corresponds in particular to the maximum opening diameter of the valve opening 28. A first shuttle valve pin 31b, for example, has a pin diameter d of 1.4 mm or1.9 mm, a second valve pin 31c has a pin diameter d of 1.3 mm or 1.8 mm, etc. By selecting suitable valve openings 28 and shuttle valve pins 31a-c, multi-stage adjustability can be ensured, whereby by exchanging the valve pin 29, the damping force can be specifically adjusted depending on the damping force deviation.

[0047] The valve pin 29 and the shuttle valve pins 31a-b each have a valve pin head 32, which serves for better handling, e.g., using tweezers or a special magnetic tool, and at the same time defines a stop in the closed position 104. In principle, the shuttle valve pins 31a-b can be designed in different colors, e.g., by colored anodizing for aluminum pins or by colored painting, to better distinguish the different pin diameters d. Alternatively, or optionally additionally, the valve pin heads 32 of the shuttle valve pins 31a-c have a different shape, as shown in Fig. 3. The selection of the appropriate shuttle valve pin 31a-c can thus be carried out more conveniently, quickly, and with a lower probability of error.

[0048] As in Fig. As shown in Figure 4, the various basic shapes of the valve pin heads 32 can be further subdivided by a further shaping, such as a slot, Phillips, etc. Thus, a valve pin replacement set 30 can be realized with a large number of different shuttle valve pins 31a-c, which are clearly distinguishable from one another.

[0049] The Fig. 5 and Fig. 6 show two different designs of the base body 14 of the piston rod guide 12 in a sectional view. In the design according to Fig. 5, the valve opening 28 is designed as a two-stage stepped bore. The valve opening 28 has a first and a second bore section 33a, 33b, with the first bore section 33a opening into the return flow channel 27 and the second bore section 33a opening into the first working chamber 6a. A bore diameter of the first bore section 33a is larger than a bore diameter of the second bore section 33b.

[0050] The valve pin 29 is inserted into the first bore section 33a, wherein the valve pin head 32 has a valve sealing surface 35 that interacts with a valve seat surface 34. The valve seat surface 34 is formed by a flat surface of the base body 14 that borders or surrounds the valve opening 28. The valve sealing surface 35 is formed by a collar that is complementary to the valve seat surface 34 and that rests flatly or at least linearly against the valve sealing surface 35 in the closed position 104.

[0051] When executed according to Fig. 6, the key difference is that the valve opening 28 is designed as a through-bore with a constant bore diameter. The valve pin head 32, as previously described, prevents the valve pin 29 from falling through the through-bore.

[0052] The following is an example procedure for adjusting the damping force within the framework of a damping force test based on the Fig. 1 to 6. Precise (digital) information about the current configuration of piston and throttle valves 8, 9, and 16 (including information about the valve pin 29 used) must be recorded in advance. If a damping force of vibration damper 1 is identified as defective during the damping force test and is rejected, the responsible employee must be clearly informed of the adjustments to be made to throttle valve 16 to adjust the damping force.

[0053] For this purpose, in the event of a damping force deviation exceeding tolerances and based on stored data, e.g. using databases, simulations, etc., a change information is determined in the background, whereby based on the change information the employee is shown which shuttle valve pin 31a-c is to be selected from the valve pin replacement set 30 to compensate for the damping force deviation. For example, the output of the change information can be indicated by displaying a shape and / or color code uniquely assigned to the shuttle valve pin 31a-c, as shown in the Fig. 3 and Fig.4, can be done via a screen display. This prevents the employee from having to act on their own discretion and possibly not immediately selecting the ideal configuration. This prevents further loops. It also saves time, as the computer calculation is faster than the employee's manual calculations.

[0054] Furthermore, it would be conceivable to integrate several of the throttle valves 16, for example, three throttle valves 16 spaced 120° apart, into the piston rod guide 12. Using very tightly toleranced valve openings 28 and valve pins 29, a very fine adjustment of the damping force can thus be achieved across all different combinations. Reference symbol 1 vibration damper 2 cylinder tube 3 Container pipe 4 piston rod 5 pistons 6a, b Working chambers 7 Compensation chamber 8 bottom valve 9 Rebound valve 10 compression valve 11 Pre-opening disc 12 Piston rod guide 13 Damper base 14 basic bodies 15 Sealing unit 16 throttle valve 17 Cylinder mount 18 Guide opening 19 Piston rod seal 20 reinforcement discs 21 Sealing section 22 Fastening section 23 sealing lips 24 support surface 25 Marginal area 26 Assembly room 27 return channels 28 Valve opening 29 Valve pin 30 valve pin replacement kit 31a-c shuttle valve pin 32 valve pin head 33a, b borehole sections 34 Valve seat surface 35 Valve sealing surface 100 Longitudinal axis 101 Direction of travel 102 Print direction 103 Opening position 104 Closed position

Claims

[1] Piston rod guide (12) for a vibration damper (1), which has a cylinder tube (2) and a container tube (3), wherein the cylinder tube (2) is arranged coaxially in the container tube (3) to form a compensation chamber (7), wherein in the cylinder tube (2) a piston (5) is arranged axially displaceably via a piston rod (4) and divides the cylinder tube (2) into two working chambers (6a, b), with a base body (14) which has a cylinder tube holder (17) for receiving the cylinder tube (2), a central guide opening (18) for axially guiding the piston rod (4) and several return flow channels (27), with a sealing unit (15) which has a piston rod seal (19) for sealing the piston rod (4), wherein a collecting chamber (26) for a damper fluid is formed between the piston rod seal (19) and the base body (14), which collecting chamber is fluidly connected to the compensation chamber (7) via the return flow channels (27), characterized by , that the piston rod guide (12) has at least one throttle valve (16) for influencing a damping force of the vibration damper (1), wherein the throttle valve (16) is formed by a valve opening (28) introduced into the base body (14), which fluidically connects a piston rod-side working chamber (6a) to the collecting space (26) and / or at least one of the return flow channels (27), and a valve pin (29) inserted into the valve opening (28), which closes the valve opening (28) in a closed position (104) and at least partially releases it in an open position (103). [2] Piston rod guide (12) according to claim 1, characterized by that the throttle valve (16) is designed to influence the damping force during a pulling movement of the piston rod (4) in that the throttle valve (16) enables a fluid flow from the piston rod-side working chamber (6a) into the compensation chamber (7) and blocks it in an opposite flow direction. [3] Piston rod guide (12) according to claim 1 or 2, characterized by that the valve pin (29) is replaceable for fine adjustment of the damping force by a shuttle valve pin (31a-c) of a valve pin replacement set (30), wherein the valve pin (29) and the shuttle valve pin (31a-c) have a different pin diameter. [4] Piston rod guide (12) according to one of the preceding claims, characterized bythat the valve opening (28) opens into one of the return flow channels (27), so that the piston rod-side working chamber (6a, b) is fluidically connected directly to the return flow channel (27) via the valve opening (28). [5] Piston rod guide (12) according to one of the preceding claims, characterized by that the valve opening (28) is designed either as a stepped bore with different bore diameters or a through bore with a constant bore diameter. [6] Piston rod guide (12) according to one of the preceding claims, characterized by in that the valve pin (29) has a valve sealing surface (35) which cooperates with a valve seat surface (34) of the valve opening (28), wherein the valve seat surface (34) of the valve opening (28) is formed optionally on a surface of the base body (14) facing the collecting chamber (26) or on a cylinder shoulder of the valve opening (28), in particular the stepped bore. [7] Piston rod guide (12) according to claim 6, characterized by that the valve sealing surface (35) is formed optionally on a valve pin head (32) of the valve pin (29) or on the end of the valve pin (29). [8] Piston rod guide (12) according to one of the preceding claims, characterized by that the sealing unit (15) has a reinforcing disc (20) for reinforcing the piston rod seal (19), wherein the reinforcing disc (20) defines an end stop for the valve pin (29) in the open position (103). [9] Piston rod guide (12) according to one of the preceding claims, characterized by that the piston rod guide (12) has at least one further throttle valve (16), wherein the further throttle valve (16) is formed by a further valve opening (28) introduced into the base body (14) and a further valve pin (29) inserted into the further valve opening (28). [10] Valve pin replacement set (30) with a piston rod guide (12) according to one of the preceding claims 3 to 9, characterized by in that the valve pin replacement set (30) has at least one shuttle valve pin (31a-c) which differs in pin diameter from the valve pin (29), wherein in a first assembly state the valve pin (29) is inserted into the valve opening (28) and in a second assembly state the shuttle valve pin (31a-c) is inserted into the valve opening (28) instead of the valve pin (29). [11] Valve pin replacement kit (30) according to claim 10, characterized by that the valve pin (29) has at least approximately the same diameter as the valve opening (28) and the shuttle valve pin (31a-c) has a smaller diameter than the valve opening (28). [12] Valve pin replacement set (30) according to claim 10 or 11, characterized bythat the valve pin replacement set (30) has a plurality of change valve pins (31a-c) which differ from one another in pin diameter, wherein the different change valve pins (31a-c) have a clearly distinguishable characteristic. [13] Method for adjusting the damping force of a vibration damper (1) with the piston rod guide (12) according to one of claims 3 to 9 and / or with the valve pin replacement set (30) according to one of claims 10 to 12, in which: - a damping force test is carried out; - if an actual damping force deviates from a target damping force, change information is determined; - based on the change information, a valve pin (29) of the at least one throttle valve (16) is changed. [14] Method according to claim 13, characterized bythat the change information is determined based on a difference value between the actual damping force and the desired damping force, wherein at least one associated change valve pin (31a-c) is selected from the valve pin change set (30) based on the change information. [15] Procedure under 13 or 14, characterized by that the change information relating to the respective change valve pin (31a-c) is output and / or displayed as an identifier uniquely assigned to each change valve pin (31a-c).

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