DE2248374A1 - SINGLE PIPE DAMPER - Google Patents

Description

DR. MÜLLER-BORE DIPL-PHYS. Dn. MANITZ DIPL.-CHEM.ÜR. DEUFEL DIPL-ING. FINSTERWALD DIPL-ING. GRÄMKOW

PATENT LAWYERS J 9 L 8 3 7 L

Munich, ³ - GKf. Erb / Cr - G 2275

GEMTCER FBASCE

'97 »rue de Verdun

SUHESIffiS, Hauts-de-Seine / FRANCE

Monotube damper

The invention relates to a shock and vibration damper, which is used in particular for suspension devices of motor vehicles is applicable.

As is known, hydraulic telescopic single-tube dampers which are installed in motor vehicles essentially consist from a tight cylinder in which a piston attached to a rod moves and the piston moves in two through the Pistons separate and with a fluid with a certain viscosity filled chambers is divided, wherein one or more openings provided in the piston of small diameter connect these two chambers and allow the fluid to flow from one chamber to the other. But with that this flow can actually take place when the piston is moving in the tube, which must be part of the change in volume in the chamber containing the rod of the piston caused by the presence of this rod will. This compensation, which is done with the twin-tube dampers a second tight tube is achieved which is arranged coaxial with and outside of the first tube and with this over the bottom of the not the rod of the piston

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containing chamber is connected to mono-tube dampers with the help of a tight chamber, which is in the bottom of the not the rod containing chamber is arranged and either with a pressurized gas or an elastic, compressible Material, for example cellular rubber, is filled · Under these circumstances this offers when the piston moves one chamber into the other is forced fluid due to its viscosity and the small diameter of the connection openings provided in the piston have a viscous resistance that is proportional to the square of the speed of relative movement of the piston and tube.

The known mono-tube dampers generally fulfill the task for which they are intended. To their impeccable However, a large number of parts are required to perform, which complicates the structure. Furthermore, the Tolerances of the fitting of the piston in the tube are quite tight. In addition, it is, without causing serious complications, often practically impossible, in a monotube damper a good compensation of the volume change due to the presence to reach the rod of the piston. An additional disadvantage of the monotube damper is that it has both when working on compression as well as on relaxation it is difficult to achieve the dosed damping force that is necessary for a good road holding of the vehicle equipped with these.

The invention overcomes these disadvantages by providing a mono-tube damper in which the number of components is greatly reduced, thereby facilitating its manufacture and consequently reducing the manufacturing cost and which gives the

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Vehicle 'can be reached. These results are essentially achieved in that the compensation chamber of the damper consists of the interior of the rod of the piston, which for this purpose is made hollow, and that the piston means for alternating connection of this compensation chamber with one or the other of the two main chambers of the damper.

The single-tube damper according to the invention is essentially characterized by this characterized in that it has a cylinder or tube closed at each of its ends by a tight cover and filled with a viscous fluid and a piston, its one surface is free and the other surface with a crossover the corresponding tight cover of the cylinder Rod is provided and which the cylinder in two main chambers with depending on the one occupied by the piston in it Position variable volume tsLlt, of which the first main chamber on the side of the surface of the piston provided with the rod and the second main chamber on the side of the free surface this piston is arranged so that the rod of the piston is hollow and the compensation chamber of the outside of this rod located volume forms and on the opposite of the piston The end is tightly closed so that the piston on the one hand has at least one channel to connect the two main cartridges: in the direction from the second to the first main chamber, a portion of which for part of the length thereof is a Chamber forms that with the Kompensärionskammer through a this chamber adjoining channel is connected and the one tared organ to close their ends and to change the passage cross-section of the fluid in this channel as a function of the overpressure existing between the second and the first main chamber, and that the piston on the other hand with at least one channel to connect the two

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the main chambers is provided in the direction from the first to the second main chamber, a portion of which is on one Part of its length forms a chamber which is connected to the compensation chamber via an adjoining this chamber Channel is connected and the a tared organ to close their ends and to change the passage cross-section of the fluid in this channel depending on the value of that occurring between the first and the second main chamber Has overpressure, this organ being tared so that the passage cross-section of the fluid in the first, the two Main chamber connecting duct at the same value of the overpressure between the two main chambers larger than the passage cross section of the fluid in the second, the channel connecting the two main chambers is.

A preferred embodiment is that the Piston consists of two equal parts that have a general shape of a ring and each with two longitudinal channels with the same diameter and with the longitudinal axis of the ring parallel and with respect to this symmetrical to each other Axes are provided, one of the two channels with the inner side wall of the ring through one on this wall discharging, radial channel is connected that these two ring-shaped parts at a coaxial to the hollow rod, cylindrical hollow end part of this rod are attached, the outer diameter of which is equal to the inner diameter of the is annular parts and has at least two radial channels connecting the interior with the exterior of this hollow part, which have the same diameter as each of the radial channels provided on the annular parts and are angularly offset by 180 and in the longitudinal direction, and

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that these two annular parts are coaxial with the same flat end face in contact with one another, but are arranged angularly offset from one another by 180, wherein their radial channels are opposite to the corresponding channels provided on the end part of the rod the longitudinal channels of the one opposite to the diametrically opposite one Channels of the other are located, which thus form the channels connecting the main chambers to one another, while the radial channels which form the channels connecting the preceding channels with the compensation chamber «

It is also useful that each of the two organs for closing and changing the cross-section of the passage from one main chamber to another under the action of the between the two main chambers existing overpressure from a group of two clamped, lamellar valves consists that the first, the channel connecting the second with the group of two valves corresponding to the first chamber, a first valve, the one between the one provided with the rod Face of the piston and the end of this rod is clamped to be movable around the clamping line and in Rest position rests against the corresponding surface of the piston and the corresponding input of this connecting channel completely closes, and has a second valve between the two contacting surfaces of the two halves of the piston is clamped, is movable about its clamping line and in the rest position the end opening of the corresponding channel section completely covers and closes the one provided in the half of the piston that is not provided with the rod is, with a free space in the other half of the piston, in which this second valve can move, that the second, the channel connecting the first with the

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group of two valves corresponding to the second chamber first valve, which is located between the free end faces of the piston opposite the rod and an end shoulder of the The end part of the rod is clamped, is movable about its clamping line and is in the rest position on this free surface of the Piston rests and the corresponding input of this connecting channel completely covers and closes, and a second valve, clamped between the two contacting surfaces of the two halves of the piston Bt to his clamping line movable Bt and in the rest position the End opening of the corresponding channel section, which is recessed in the half of the piston provided with the rod, completely covers and closes, with a free space in the other half of the piston, in which the second valve can move, and that the rigidity of the second valve of the second group of valves is greater than that Stiffness of the first valve of the second group.

The first valve of the first group expediently has the same rigidity as the second valve of the first group and a tared compressible spring is inserted between the two valves of the second group.

Further details and advantages of the invention emerge from the following description of an exemplary embodiment, reference being made to the accompanying drawings. Show it:

1 shows an axial section through an inventive Monotube damper,

2 shows an enlarged section; through the piston of the

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Damper, with the course of the fluid at work of the damper is shown on compression.

Fig. 3 shows an axial section corresponding to FIG. 2 through the Piston of the damper, showing the course of the fluid when the damper is working on relaxation.

In these figures, the same elements are denoted by the same reference numbers. · ·

As FIG. 1 shows, the single-tube damper according to the invention has a cylinder or tube 1 which is tightly closed at one of its ends by a cover 2 which covers the whole Assumes cross-section of the cylinder and with a rod for connecting this cylinder, for example, to a suitable one Part of a vehicle chassis can be provided. At the other end, this cylinder 1 is closed by a tight cover 3 through which the rod 4, which is coaxial with the cylinder of the piston 5 which is coaxial with the cylinder, passes and can move under a seal. This cylinder is filled with a fluid with a certain viscosity, for example oil, filled. The rod 4 consists of a tube, one end of which is firmly connected to the piston 5 and the other end End is sealed by a part 6, which is connected by a full, with another suitable part of the vehicle Rod is extended. This hollow rod forms the Compensation chamber for the volume outside the rod when the piston and thus the rod move in the cylinder, and is, as "will be explained in the following, soon with the one between the cover 3 for the passage of the rod and the one the side of the piston attached to the rod and

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The part of the cylinder called the first main chamber 8 (in which the rod 4 moves) will soon be connected to that part of the cylinder located between the free side of the piston and the cap 2 and called the second main chamber 9. These two main chambers have, depending on the Position of the piston in the cylinder variable volume, since the piston, as will be explained later, is designed in such a way that it allows the flow of the viscous fluid on the one hand between these two chambers and on the other hand between each of these chambers and the compensation chamber * As in particular the Pig . 2 and 3 show, the piston 5 consists of two parts 10a and 10b or equal piston halves.Each of these parts with a generally cylindrical annular shape, the outer diameter of which is the same as the inner diameter of the cylinder, has two cylindrical longitudinal channels 11a, 12a and 11b, 12b with the axes AA and BB parallel to the axis XX of the cylinder 1. These longitudinal channels are symmetrical to one another with respect to this axis XX and have the same diameter. The channel 12a is connected to the inner side wall of the part 10a via a radial channel 1Ja opening out on this wall, while the channel 12b is connected to the inner side wall of the part 10b via a channel 13b opening out on this wall. When the parts 10a and 10b are coaxially arranged so that two of their corresponding sides are in contact and offset by 180 ° from each other so that the axes of their longitudinal channels coincide, the channel 11b of the part 10b becomes the channel 12a of the part 10a coaxial, while the channel 11a of the part 10a becomes coaxial with the channel 12b of the part 10b, as shown in Figs. The two parts 10a and 10b arranged in this way together form the piston

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of the single tube damper according to the invention. Fixing this Piston on the hollow rod 4 is achieved in the following way: A hollow body of revolution 14 with the axis X-X is tightly attached to this hollow rod 4 in any known manner. This part 14 is coaxial with this hollow rod. This end part 14 of the rod 4, the outer diameter of which is the same .dem the inner diameter of the parts 10a and 10b is with two radial channels 15a and 15b provided, which its outer wall and connect its inner wall together. These channels are on the one hand angularly offset by 180 and on the other hand in Offset in the longitudinal direction, so that the radial channel 15a, when the piston 5 is attached to the rod 4 via its end part 14 was, opposite the radial channel 13a of the part 10a and the radial channel 15t> is opposite the radial channel 13b. The group of the two channels 13a and 15a forms thus a single channel for connecting the channel 12a, 11b to the internal chamber of the hollow rod 4 and the group that both channels 13b and 15b form one in the same way single channel for connecting the channel 12b, 11a with the inner chamber of the rod 4. The piston that consists of the two the same parts 10a and 10b arranged in the manner described above is at the end part 14 of the rod 4

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fastened in any suitable manner. For example, the inner side wall of each part 10a and 10b is internally threaded, while the outer wall of part 14 is internally threaded with two externally threads having the same thread as the internally threaded but in opposite senses, each of which extends over one Height which is equal to the height of each of the parts 10a and 1.0b. The part 10a is first screwed onto the part 14 until it abuts the end shoulder 16 of the part 14. Then the part 10b is screwed onto the part 14,

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until it comes into contact with the part 10a and is offset angularly by 180 ° with respect to this. The one educated in this way The unit can now be tightly attached to the hollow rod 4 in any suitable known manner, the Front side of the end of the tube forming the rod abuts the free end face of part 10b. At the same time with This assembly work, two valves are attached to each of the channels 12a * 11b and 12b, 11a, which the organ for closing and changing the opening of these channels. The channel 12b is for this purpose at its with the main chamber 8 end in contact with a valve 17b known Type provided - for example, from a between the front wall the end of the hollow tube 4- and the free face of the part 10b clamped lamella, which covers part of this end face, in which the circumference of the end this channel is included. In the same way, the non-free end of the channel 11a is with one of the above Valve-like valve 18a is provided, which is either clamped between the contacting end faces of the parts 10a and 10b is or screwed in the non-free end face of the part 10a vertically below the clamping point of the valve 17b is (case of Figs. 2 and 3). The features of these two lamellar valves 18a and 17b are chosen so that that the deformations that they suffer depending on the forces acting on them, according to a predetermined regularity get lost. In the same way, the channel 12a is at its end contacting the main chamber 9 with a Valve 17a of the same type as the above-mentioned valves provided between the end shoulder 16 of the part 14 and the free end face of the part 10b is clamped, while the non-free end of the channel 11b with a valve 18b of the type of valve 17a is provided in the same way

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how the valve 18a is attached. To enable the movements of the valves 18a and 18b, are in parts 10b and 10a, which they face, suitable recesses are provided. The section of the longitudinal channel with the axis A-A between the two valves 17a and 18b thus forms a chamber which, when these two valves are in the rest position, i.e. 'in the position in which they open the end openings of the channel 12a close, only with the compensation chamber 7 via the radial channels 13a and 15a and the cylindrical hollow part of the end part 14 der'Stange 4- is in connection. Likewise educates the section of the longitudinal channel with the axis B-B between the two valves 17b and "18a a chamber which, \ tfenn the valves are in the position in which they close the end openings of the channel 12b, only with the chamber 7 via the radial channels 13b and 15b and the hollow part of the part 14 in connection are.

The monotube damper formed in this way, in which the viscous Fluid the entire volume of the main chambers 8 and 9 and fills a more or less large part of the compensation chamber ·. "· 7, soon works on compression, whereby the piston ' under the effect of the forces acting on it, the viscous fluid approaches the closure cover 2 of the cylinder as a result is compressed in the chamber 9 and its rod moves into the chamber 8, soon to relax, whereby the piston moves away from the cover 2, the fluid in the chamber 8 is compressed and its rod moves out of this Chamber moved out.

When the damper is working on compression (Fig. 2), i.e. when the piston 5 is in the cylinder 1 in the direction of the arrow F.

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moves, the fluid contained in the chamber 9 is compressed and on the one hand exerts a force on the valve 17a which holds it in the position closing the inlet of the channel 12a and consequently any connection via the channel of the axis AA between the chamber 9 and the Chamber 8 and between the chamber 9 and the compensation chamber 7 blocks. On the other hand, the fluid here exerts a force on valve 18a which causes it to open, the value of this opening being an increasing function of the value of this force. This opening allows the fluid to enter the chamber 12b under pressure. This fluid now exerts a force on valve 17b which causes it to open so that chambers 8 and 9 on the one hand and these two chambers and compensation chamber 7 on the other hand are connected to one another via the channel of axis BB. Since the rod 4 enters the chamber 8, the decrease in the volume of the chamber 9 is greater than the increase in the volume of the chamber 8, and since the fluid is incompressible, no movement of the piston would be possible if the chamber's fluid volume is in excess 9 cannot be absorbed by the compensation chamber 7. Only part of the fluid volume of the chamber 9 enters _{the chamber 8 according to the path indicated by the arrows f., F 2} and f ^, while the fluid volume excess enters the chamber 7 in the path indicated by the arrows f ^, and fc » ie enters the interior of the hollow rod 4- of the piston. The characteristics of the valve 18a must be determined, ie this valve must be tared so that the damping force it generates is compatible with that of the compression valve 17b. The valve 18a has the task of modulating the flow of the fluid through the compensation channel 13b, 15b during compression and, during expansion (cf. Fig. $), The return flow of the fluid from the compensation chamber to the chamber 9 only via the channel 13a To allow 15a. The presence of this ven-

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tils 18a can also be avoided that the compensation channel 13b, 15b must be precisely calibrated.

When the damper works on relaxation (Fig. 3) j ie. When the piston 5 moves in the cylinder 1 in the direction of the arrow Fp, the fluid contained in the chamber 8 is compressed and on the one hand exerts a force on the valve 17b which holds it in the position closing the inlet of the channel 12b and consequently blocks any communication via the channel of the axis BB between the chamber 8 and the chamber 9 and between the chamber 8 and the compensation chamber 7. On the other hand, the fluid contained in the chamber 8 exerts a force on the valve 18b which causes it to open, the value of which is an increasing function of the value of this force and which allows the pressurized fluid to enter the chamber 12a, which is now exerts a force on valve 17a which causes it to open, so. that the chambers 8 and 9 on the one hand and these two chambers and the chamber 7 on the other hand are connected to one another via the channel of the axis AA Reduction of the volume of the chamber 8 and, since the fluid is incompressible, no movement of the piston could take place without a vacuum being created in the chamber 9 if the chamber 7 does not have fluid to compensate for it. Volume would deliver. The fluid absorbed by the chamber 9 comes partly from the chamber 8 via the channels 11b and 12a and takes the path indicated by the arrows fg, fr ,, fg and fg, and partly from the compensation chamber 7 via the channel 15a, 13a and takes the path indicated by the arrow f ^ Q and the arrows f _Q and fg.

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In order to achieve a difference in effect between the work on compression and the work on relaxation of the damper, which corresponds to the requirements of the vehicle on which it is mounted, the expansion valve 18b is given a greater rigidity than the compression valve 18a, so that the opening of the The passage of the fluid from the chamber 8 to the chamber 9 through the channel with the axis AA under the action of a pressure difference of the same value between the chambers 8 and 9 is less than the opening of the passage of the fluid from the chamber 9 to the chamber 8 via the Channel with axis BB. The same result is expediently obtained as follows: The valves 18a and 18b are the same and consequently have the same rigidity. In the chamber 12a, however, a tared, compressible spring 19 is inserted between the relief valve 18b and a shoulder 20 provided in this chamber, which spring 19 serves to increase the rigidity of this valve.

Thanks to the production of the piston from two identical, coaxially arranged opposite one another and angularly 180 to one another offset parts, the double valve 18a and 13b can be inserted between the compression valve 17b and the expansion valve 17a. This / double valve, the piston halves 10a and 10b and the valves 17a and 17t> are through Attachment of the piston to the end portion 14 of the rod held in place by gripping, screwing or opening can be fastened in or on the hollow rod 4 in any other suitable manner.

Since this hollow rod on its opposite to the piston 5 The end is tightly closed by the bottom 6, the one on the side of this bottom is not with viscous fluid filled part of the compensation chamber 7 filled with air,

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which is compressed when the chamber 7 absorbs fluid, i.e. when the damper is working on compression, and which, relaxed when fluid flows from chamber 7 into chamber 9, i.e. when the damper works on relaxation. Experience has shown that despite this phenomenon of compression and pressure reduction of those contained in the compensation chamber Air excellent, even surprising results be achieved. Experience has shown, however, that when the vehicle equipped with such dampers is used, it can occur outside in the street or in the tropics, in the soil 6 of the piston rod to provide an opening with a very small cross-section, which the air-filled part of the chamber 7 with the atmosphere connects. This measure is normal Use in European countries is not absolutely necessary.

The piston 5 can be made of both sintered metal and machined Metal, synthetic material or any other commonly used for the manufacture of damper pistons Material.

The single-tube damper described above has all the advantages of operating two-tube dampers without the structural disadvantages the known mono-tube damper. Because of its simple structure, its manufacturing cost is lower than that of the twin-tube damper.

Claims;

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Claims (4)

Patent claims Single-ring damper, characterized in that that it has a sealed lid (2, 3) at each of its ends and coated with a viscous 3? luid filled cylinder or tube (1) and a piston (5), one surface of which is free and the other! surface with a rod (4) traversing the corresponding tight cover (3) of the cylinder and that of the cylinder in two main chambers with variable depending on the position occupied by the piston in it Volume divides, of which the first main chamber (8) on the side of the surface of the piston provided with the rod and the second main chamber (9) is arranged on the side of the free surface of this piston that the rod of the The piston is hollow and the compensation chamber (7) cles outside this rod located volume forms and sealed at the end opposite the piston is that the piston on the one hand with at least one channel (11a, 12b) for connecting the two main rabbits in the Direction from the second to the first main chamber, a portion (12b) of which on a part thereof Length forms a chamber which is connected to the compensation chamber through a channel (13b) adjoining this chamber is connected and a tared organ (1Sa) for closing its ends and changing the passage cross-section of the fluid in this channel as a function of the overpressure existing between the second and the first main chamber, and that the piston on the other hand with at least one channel (11b, 12a) for connection of the two main ridges in the direction of the 309845/0329 first to the second main chamber is provided, one of which Section (12a) on part of the length of which forms a chamber, which is connected to the compensation chamber via a this chamber adjoining channel (13a) is connected and a tared member (18b) for closing their ends and for changing the passage cross-section of the Fluids in this channel as a function of the value of the overpressure occurring between the first and the second main chamber, this organ taring so is that the passage cross-section of the fluid in the first, the two main chambers connecting channel at the same value of the overpressure existing between the two main chambers is greater than the passage cross-section of the fluid is in the second channel connecting the two main chambers. 2. Single tube damper according to claim 1, characterized in that the piston consists of two identical parts (10a, 10b), which have a general shape of a ring and each with two longitudinal channels (11a, 12a and 11b, 12b) with the same diameter and with the longitudinal axis of the ring parallel and with respect to each other symmetrical axes are provided, one of the two channels (13a, 13b) with the inner side wall of the ring is connected by a radial channel (15a, 15b) opening out on this wall, so that these two are annular Parts are attached to a cylindrical hollow end part (14) of this rod which is coaxial with the hollow rod, the outside diameter of which is equal to the inside diameter of the annular parts and the at least two are the inside with the exterior of this hollow; connecting radial part Channels (15a, 15b) has the same diameter as 309845/0 323 each of the radial channels (13a, 13b) provided on the annular parts and at an angle of 180 and are offset in the longitudinal direction, and that these two annular parts are coaxial with the same flat end face are in contact with each other, but are arranged offset angularly by 180, their radial Channels (13a, 13b) are opposite to the corresponding, channels (15a, 15b) and the longitudinal channels (Ha, 11b) of the one located opposite the diametrically opposite channels (12a, 12b) of the other, which thus form the main chambers (8, 9) form interconnecting channels, while the radial channels each form the preceding channels with the compensation chamber (7) form connecting channels. 3 · Single pipe damper according to one of Claims 1 or 2, characterized characterized in that each of the two organs for closing and changing the cross section of the Passage from one main chamber to the other under the effect of the overpressure between the two main chambers (8, 9) consists of a group of two clamped, lamellar valves that the first, the channel to Connection of the second group of two valves (17b, 18a) corresponding to the first chamber, a first valve (17b), which is clamped between the end face provided with the rod of the piston and the end of this rod, around the Clamping line is movable and in the rest position rests against the corresponding surface of the piston and the corresponding Entrance of this connecting channel is completely closed, and has a second valve (18a), which is between the two contacting surfaces of the two halves of the piston is clamped to its clamping line is movable and in the rest position the end-off only 130.es off the corresponding channel 309845/0329 Section completely covers and closes, which is provided in the half of the piston not provided with the rod, with a free space in the other half of the piston, in which this second valve can move, that the second, the channel for connection the first group of two valves (I7a ₅ 1Sb) corresponding to the second chamber, a first valve (I7a) which is clamped between the free end face of the piston opposite the rod and an end shoulder of the end part of the rod, is movable about its clamping line and in the rest position rests against this free surface of the piston and completely covers and closes the corresponding inlet of this connecting channel, and has a second valve (18b) which is clamped between the two contacting surfaces of the two halves of the piston, movable about its clamping line is and in the rest position the end opening of the corresponding channel section, which is in the with the Stan Ge provided half of the piston is recessed, completely covered and closed, with the other half of the piston. A free space is recessed, in which the second valve is. can move, and that the rigidity of the second valve (18b) of the second group of valves is greater than the rigidity of the second valve (18a) of the. second group is. 4. Monotube damper according to one of claims 1, 2 or 3? through this It is indicated that the second valve (18b) of the first group of valves has the same stiffness like the second valve (18) of the second group 'possesses and that a tared, compressible spring is inserted between the two valves (17a-18b) of the second group is. 3 0 98 45/03 2.9 INSPECTED