SE528895C2 - Attenuator with sealing function - Google Patents

Abstract

The damper can be fastened to reciprocally moving parts on a vehicle and is provided with an enclosing piston and connecting rod arrangement together with a pressure guaranteeing component which ensures maintenance of pressure in the arrangement when a pressure-affecting parameter occurs which strives after another pressure. The piston connecting rod and its components are sealed in two gables or in a gable and a wall in the arrangement by only two seals and sealing components to achieve optimally low friction.

Description

lO 15 20 25 30 528 895 cylinder bore can be reduced. The volume of the damping medium or the damping media must be kept within certain intervals to ensure the function of the damper. There is also a desire for the seal/seals/bush/bushes to be placed as close to the main piston as possible in order to minimize the length of the piston rod arrangement and thereby minimize the total length of the damper without incurring expensive machining costs. In the case where a top eye is used, it should be easy to mount at any angle to the damper body without the reading of the top eye interfering with the length of the damper. The invention has the purpose of solving all or parts of the additional problems specified.

What can mainly be considered to be characteristic of a damper according to the invention is apparent from the characterizing part of the following patent claim 1.

In a detailed embodiment, the pressure-guaranteeing means preferably comprises a gas-separating piston. The piston rod or piston rod elements are arranged through and sealed by means of two seals/sealing elements in two ends or in one end and one wall.

The gas separation piston is located outside the path of movement of the relevant piston rod or relevant piston rod element and is internally sealed with a seal against the top loop.

By the gas separation piston being included in a connecting path for the fluid movement of the media between the upper and lower sides of the main piston, no or no extra channels need to be arranged for the establishment of the media transport. This in turn provides opportunities to reduce the volume of the damper as such and/or enable a reduced manufacturing cost in the damper.

The invention is advantageously used in dampers with assembled components such as cylinder, piston and piston rod arrangement, section with accumulator and fastening means in a common unit, in which the invention can take care of the complete sealing function between moving parts. 10 15 20 25 30 528 893 Further developments of the damper tank are apparent from the subsequent subclaims. Where, for example, the piston rod arrangement is described as running inside a recess in the cylindrical part of the top loop sealed against the damper head so that the arrangement can work with an optimally small fi-ction.

The design and assembly of the top eye allows it to be rotated around its longitudinal axis and locked in any direction along the longitudinal axis. The angle of rotation can be adjusted without the risk of leakage from the damper. At the same time, the top eye can be assigned angle positions where it is optimized for connection to the relevant moving part in or on the vehicle.

This rotation angle adjustment allows you to adjust the direction in which the adjustment elements point. This is to facilitate adjustment on the vehicle.

A currently proposed embodiment of a damper that exhibits the characteristics that are significant for the invention will be described below with simultaneous reference to the attached drawings, where Figure 1 in the principle diagram shows a damper and components connected to or included in it, Figure 2 in longitudinal section shows parts of a structural embodiment of the damper, Figure 3 in cross-section and enlarged in relation to Figure 2 shows the damper according to Figure 2, Figures 4-6 in longitudinal section and enlarged show the components of the damper at the damper head, and Figure 7 in end view shows the detailed structure of the damper.

In Figure 1, parts of a damper are generally indicated by 1. In the exemplary embodiment, the damper consists of a double-tube damper, the outer tube of which is indicated by 2 and the inner tube by 3. The tubes are arranged with an intermediate gap 4 and have passages 5, 6 at the first end of the damper for a medium arranged in the damper. The damper may be of the type which comprises a main piston 7 and a piston rod 8 extending through the main piston 7, where the piston rod part at one side of the piston is indicated by Sa and the piston rod part at the other side of the piston is indicated by Sb. The compression space or compression side of the damper is indicated by 9 and the expansion space or expansion side by 10. The piston and the piston rod are slidably arranged in the cylinder bore 9, 10 in the directions of the arrows 11. The piston 7 operates in a medium 13 which preferably consists of hydraulic oil which may include associated additives in a manner known per se. Alternatively, glycol and/or water may be used as the liquid. The piston rod 8a and 8b may extend from the upper and lower sides 7a and 7b of the piston, respectively. The piston rod may in principle comprise piston rod element parts which may be more than one in number. Thus, the piston rod part 8a and/or 8b may consist of more than one piston rod part or piston rod element. For example, The piston rod part 8a can consist of one piston rod part, while the piston rod part 8b can be replaced by two or more piston rod elements. The end parts of the damper are indicated by 12 and 12". The piston rod end 8c of the piston rod part 8a has fastening means 15 (e.g. end eye) to a part of a relevant vehicle, which part can consist of a wheel suspension part (hub, spindle, etc.) 14. At the damper end 8d, the damper has a fastening means 15' (e.g. top eye) which can be attached to a chassis part 16 of a relevant vehicle.

The damper is provided with a valve arrangement which is principally indicated by 17.

The valve arrangement is referred to in the present application as working means. Said means comprise a first damper force generating valve or compression damping valve 18 and a first check valve 19. In addition, a second damper force generating valve or return damping valve 20 and a second check valve 21 are included. These damper force generating valves can themselves consist of one or more parallel and/or series-connected valves. In accordance with figure 1, an accumulator or gas container 22 is also included which comprises a separating piston 23. The gas container encloses in a first space 22a medium 13, e.g. said hydraulic oil with possible additives or other liquid (see above). The gas container also has a second space 22b which comprises a second medium 24 which is more compressible than the medium 13. The medium 24 can consist of gas, e.g. air, nitrogen or other gas with additives. Said working means 17 also includes connections that interconnect said valves 18, 19, 20 and 21 and the space 22a in the container 22 and the gap 4 and the spaces 9 and 10 in the damper. In this embodiment, the gap 4 and the space 10 can be considered as a common space.

Said valves 18 and 19 are thus included in a first loop comprising the space 9, the connection 27", the space 22a, and the connection 27, and where the gap 4, the passage(s) 5 and 6 are connected as well as the space 10. A second loop consists of the valves 20 and 10 with otherwise the same connections. The flow direction in connection with the compression of the shock absorber, often referred to as the compression phase, is indicated by the arrows 26 while the flow direction in connection with the expansion of the shock absorber, often referred to as the return phase, is indicated by the arrows 26". In one embodiment, it is entirely possible to build valves into the main piston 7 that are used in combination with other valves. The first damping force generating valve 18 is connected with one end to the space 9 in the damper, while the first check valve 19 is connected to the gap 4. The second damping force generating valve 20 is connected to the gap 4, while the second check valve is connected to the space 9. Said first valves 18 and 19 are also connected to the other valves 20 and 21 via the connections 27', 22a and 27. During compression movement in the damper, i.e. When the piston 7 moves to the left in Figure 1, the medium 13 is pressed via the valve 18 and the intermediate connection and the check valve 19 into the gap 4. The gap 4 thus leads the medium diverted from the space 9 to the space 10. Depending on the design of the valve 20, more or less medium can also be led from the space 9, via the valve 18, the connection 27', the space 22a, the connection 27 and the back way through the valve 20 (i.e. against the indicated arrow direction 26') and the gap 4 to the space 10, compare the so-called bleed function.

In a corresponding manner, during expansion movement, i.e. the movement of the piston to the right in Figure 1, the medium is led from the space 10 to the space 9 via intermediate connections, the gap 4, the valve 20, the space 22a and the valve 21. Here too, it is true that more or less medium can be led, among other things, via the connections 27, 27' and the back wave through the valve 18 (against the indicated arrow direction 26) to the space 9, compare bleed function. This transfer function between the spaces 9 and 10 is referred to in the present application as positive pressure build-up, which is characterized by the fact that the medium located on the side facing the direction of movement of the piston is prevented from falling significantly below a medium pressure that exists before the current movement of the piston. When the piston moves to the left in Figure 1, the medium in the space 10 will thus maintain its significant pressure value despite the movement. In a corresponding manner, the medium in the space 9 maintains its pressure value when the piston moves to the right thanks to the aforementioned media transfer. If, for example, the piston moves in the direction of arrow lla, the pressure increase at the side 7a of the piston facing in the direction will be increased by the valve element 18 at the same time as cavitation effects are avoided at the side 7b facing from the direction of movement lla. The same applies to movements in the direction of arrow llb. The direction of movement of the medium at the gap 4 and the passages 5 and 6 in the damper has been indicated by 28. Figure 1 also shows a low-pressure zone 29 for the surrounded or enclosed medium, which can consist of, for example, hydraulic oil, nitrogen gas, etc. 10 15 20 25 30 528 895 The gas container with the gas separator piston 23 guarantees that the desired pressurization, i.e. suitable media pressure, is present in the damper 1 during volume changes. Thus, suitable pressure levels are ensured during changes in sealed volume due to e.g. temperature changes in the media volume, changes in piston rod displacement, etc.

The pressurization causes the absolute pressure level to be maintained at a sufficient level, e.g. at a level of about 2 bar or higher, to minimize the risk of cavitation due to the existing restrictions in the relevant channels. The substantial maintenance of the gas pressure on the media volume facing from the direction of movement is to a certain extent determined by the pressure drop caused by the valves and the lines or channels. The media pressure on the side facing from the direction of movement must, however, be substantially maintained at the level of the value that exists when the piston is stationary. In Figure 1, forces transmitted to the piston rod are shown by F1 and F2. With regard to valves 18 and 20, these have only been shown symbolically. In addition to the valve function itself, there are also surrounding arrangements in a manner known per se, e.g. arrangements that include springs, cones, fixed restrictions, shims, etc., as explained below. As regards the inner tube in the double tube pair, this is shorter than the outer tube and comprises one or more open passages between the gap 4 and the space 10. The reference numeral 25 is intended to symbolize the connection system or said working means in its entirety.

Figure 2 shows a structural embodiment of the damper 1 which has a form referred to herein as a double-tube damper pair. The damper pair comprises a damper head 30 (referred to herein as a portion).

At one side of the damper head, the inner and outer tubes forming the double-tube damper are arranged. The gas pressure container 22 specified above is applied to or in the damper head, at the other side thereof. The container 22 has the form of an annular component which is sealed against the fastening member 15' by means of seals 32 and 32" and against the damper head by means of seals 32" and 32"'. In addition, a seal 31 is included which prevents leakage of damping medium to the interior of the fastening member. Said fastening member has a fastening part 15a and a cylindrical part 15b, on the outside of which said seals 31, 32 and 32" are arranged. Said piston rod part 8b is arranged to be able to run inside the recess 15c of the cylindrical part during movements of the piston. Pressure indicating means are shown with 33 and 33". With the aid of these indicating means the position of the floating piston 23 (see figure 1) can be indicated. In the present case the piston is mounted on a common piston rod 5a, 8b which itself may comprise parts which can be assembled. The piston rod arrangement is mounted with first and second bushings 35 and 36, whereby the first bushing is arranged in connection with the damper head 30 and the second bushing 36 is arranged to the end face 37 of the damper. Adjustment means for setting the damping character in the damper are indicated with 38 and 38a (see figure 3). The various components in the dampers are otherwise sealed with sealing means in a manner known per se.

In accordance with Figure 3, the damper may comprise two adjusting means, which are generally designated 38 and 38a. The adjusting means may be constructed in an identical manner and have the same mode of operation. Respective adjusting means comprise a bleed valve 39, a cone valve 58, a shim valve 40 and a check valve 41 with a wave plate 59 which creates a tensioning force (which is preferably close to zero). The compression bleed valve is arranged parallel to the compression cone valve and the expansion bleed valve is arranged parallel to the expansion cone valve. The positions of the bleed valves can be changed from the outside by means of tools, e.g. screwdriver, via cooperating means, such as e.g. can be formed by chisel grooves 60. The poppet valves are pressed against their respective seats 42 by means of prestressed springs 43. The prestress of the springs is adjustable from the outside v by means of an adjusting screw 44, which can be actuated with a suitable tool, e.g. a socket or block wrench. The size of the prestress affects the opening pressure and thus the pressure differential across the main piston. The shim valves 40 are arranged at the front of the poppet valves. The shape of the poppet and the shim package or shim stack affect the damping characteristic.

The shim configuration can be varied. The damper structure with the placement of valves, check valves, gas reservoirs, channels, etc. enables the compression and expansion valves to operate independently of each other. In one embodiment, a rigid shim stack can be used in combination with a small preload on the plug valve. The oil or liquid that is passed through the bleed valves and the shim stack can be very limited before the plug valve opens. The opening pressure of the plug valve depends on the designs of the plug valve and the valve seat and the preload of the spring. By changing, among other things, these parameters, the character of the damping curve can be changed or selected. The reference numeral 62 shows a channel leading to the gap 4, while the reference numeral 63 shows a channel leading to the space 9. The channels to the space 22a start from the spaces 64, 64°, which is not shown in Figure 2, however. Said inner tube can be arranged to ensure maximum rigidity in the damper construction. The damper uses bushings that are statically arranged so that a long minimum distance between the bushings (in this case constant design), compared to the case where the bushing is placed on the piston, to minimize friction and achieve maximum rigidity in the damper when introducing bending moments and side loads. In a preferred embodiment, the piston is arranged without a bushing. As an alternative in such a case, a piston seal that does not accommodate concentricity can be used. Two identical seals of e.g. x-ring type can be used, one of which is used for the externally extending piston rod part and the other for the displacement piston rod. Thanks to the low gas pressure, the friction from the seals can be kept at a low level. The gas container can be arranged with the same diameter as the valves, whereby the oil volume 22a between the gas separator piston and the cylinder head can be used to transport oil between the two valves.

The damper is provided with said pressure indicators 33, 33' in accordance with figures 4, 5 and 6. The indicators work with a number of functions. Among other things, the indicators indicate whether the damper is pressurized or not. In a damper of this type, there is no force from the internal pressurization on the piston rod leading out of the damper body. Therefore, it is difficult to determine whether the damper is pressurized or not. By acting on one or both of the pressure indicators, a response to any pressure can be easily obtained. When the respective indicator is pressed, the respective indicator will be pressed back outwards by any pressure located inside. If pressure is not present, the indicator or indicators will assume their pressed positions. Figure 4 shows the pressure indicators in partially pressed positions. The holes or recesses where the pressure indicators can be viewed are used to tighten or loosen the top eyelet. The indicators can also be used to position the moving piston when the damper is filled or possibly emptied with oil.

The instrument in question was used on the top loop to position the piston in question.

In Figure 4, the push-in and push-out slots are indicated by F3, F4, F5 and F6.

The separator piston is in this case shown at 45 and the gas volume of the gas container is shown at 22b'. The liquid volume in the container is indicated at 22a". The respective indicators 33, 33" have the form of a stick, the inner end 33a of which is actuated by the pressure in the space 22b".

The lug 33b on the pressure indicator rests against the lug 62 in the container end face when there is internal overpressure and no external force is applied by means of a tool (see e.g. Figure 5) or the like. The pressure indicator pin can also be pressed in to abut against the piston 45, whereby information is obtained in a simple manner about the position of the separator piston, e.g. setting position. Regardless of the setting of the adjustment means 38 and 38a, the pressure in the space 22a" can be maintained substantially constant. The reference numeral 46 shows a channel suitable for filling with oil sealed with a screw 47 in combination with an O-ring 61.

The screw bottoms against a seat 48. 10 15 20 25 30 528 895 Figure 5 is intended to show the case when the pin 33a abuts against the upper surface 45a of the piston 45.

By pressing in the respective pressure indicator 33, 33' using tool 55, it is easy to determine the pressing lengths L1 and L2 for the pressure indicator parts 33a and a gap L3 for the position of the piston 45 in relation to an inner surface 48 in the piston head 49 opposite its underside 45b. This allows checking that the position of the separating piston 45 and thereby the damper medium level are within a predetermined approved working range.

By utilizing two pressure indicators, it is understood that the piston can be actuated by means of the pressure indicators without significant bias loading of the piston. The top loop can be locked in any rotational direction along the longitudinal axis 53 by screwing the container end 63 outwardly against the reading 65 via the thread 64 and fixing the top loop in the desired rotational position. The tool 55 or the equivalent can be used for this fixing function. At the said rotational angle position, the top loop is rotated about the said longitudinal axis. The rotational angle adjustment can be done without there being a risk of leakage from the damper. At the same time, the top loop can be assigned angular positions where it is optimized for connection in the relevant moving part in or on the vehicle. By means of this rotational angle adjustment, it is possible to adjust in which direction the adjustment means point. This is to facilitate adjustment on the vehicle. When the top loop ~ has been adjusted in rotation angle, it is locked to the body of the damper head with screw connections 64. The aforementioned geometric stops constitute a locking ring 65 and a locking lug 66. Pressure indicators can also be arranged so that it can be checked whether the damper and gas media are located within predetermined pressure ranges.

The piston rod or piston rod elements are arranged through and sealed in two ends or in one end and one wall. The piston rod or piston rod elements are arranged with substantially equal cross-sectional areas on both sides of the main piston.

In figure 6, application of a tool 50 is shown which is cooperative with the tool 55 and lugs 51 on the top eye 52. By arranging these tools installed, the separator piston 45 is prevented from being displaced to the left in figure 6 when the oil or the equivalent is filled into the damper under pressure. The oil filling can be done via a channel 46, compare figure 4.

Figure 4 thus shows how force is applied to push the pressure indicators towards the lraff from internal overpressure of or in the gas container. This thus provides an indication of whether the damper is pressurized and the possibility of estimating the internal overpressure. Figure 5 shows how the oil level 10 15 20 25 30 528 895 10 in the damper can be checked with a tool. If you want to check the distance L3, this can be done by measuring the distance L2 or in the case shown, even better the distance L1. In the latter case, the distance L1 in an example of an implementation should be within the interval 1+0.5/-1. This means that the distance is easy to check and determine. If the measuring tool is in contact with the container end, oil should be added. Figure 6 shows how positioning of the separator piston can be done, e.g. when filling the damper with oil under pressure.

The cylindrical part of the top eye 15" extends mainly in a recess arranged in the damping head. In this embodiment, the cylindrical part has a length that is essentially half the length of the total length of the top eye. The recess 15c extends along the most significant parts of the cylindrical part which, at the portion of the top eye projecting outside the damping head, has a portion widened in the plane of the figure which supports said stop surfaces for applicable tool 50. The stop surfaces 51 extend radially outside the cylindrical portion 15b. The cylindrical portion is opposed to the space 22 at its middle parts.

Said seals for the cylindrical portion arranged on both sides of the space 22. Said stop surfaces 51 (figure 6) supporting portion 15a is essentially disc-shaped and has in the direction perpendicular to the plane of the figure in e.g. figure 6 a thickness which is essentially of the same size as the outer diameter of the tubular part. The twisted part is arranged symmetrically about the central axis. The part or portion 52 is provided with a recess 52c extending perpendicular to the plane of the figure, in which is arranged a spherically shaped unit 52a and a member 52c formed with a cylindrical outside and a spherical inside. A not shown loading member, e.g. a fastening screw, may extend through a recess in said unit 52a and be fixed in the relevant movable part on either side of the portion 52. The latter portion is essentially semicircular in shape in the plane of the figure.

The directions of rotation of the top eyelet about the longitudinal axis are shown by arrows 57. The end eyelet 15 has a corresponding structure with a cylindrical part 15d and a flat part 15e. The piston rod 8a projects into a recess 15f, at which a lock nut 151 is arranged. A recess 15h extending perpendicularly to the plane of the figure in Figure 2, sphere 15i and associated outer ring 15k are arranged to receive an elongated fastening member (not shown) extending substantially perpendicularly to the plane of the figure. The end eyelet can also assume different rotational positions about the longitudinal axis of the coupler and the dimensions and design of the end eyelet can be selected in a similar manner to the top eyelet. By means of the proposed method, the position of the gas separator piston can be positioned in a simple manner with one or more pressure indicators of the pressure indicators mentioned in the above. By the fact that a medium-allocated space 22a in the accumulator or container of the gas separator piston is included in a connecting path for the medium's flow between the upper and lower sides 7a, 7b of the piston, i.e. the main piston 7, compare the above, no or no additional channels need to be arranged for the establishment of the media transport. This in turn provides opportunities to be able to reduce the volume of the damper as such and/or enables a reduced manufacturing cost in the damper. By the fact that the piston rod arrangement is sealed in the damper arrangement by means of only two seals/sealing elements 36a and 37a, the arrangement can operate with an optimally low friction. Up to now, the use of at least three seals has been required.

In Figure 7, the coupler 1 is shown in end view from the top loop side, with two rotational angle positions indicated by solid and dashed lines 15' and 15". In the present case, the top loop has been rotated through an angle 0z which is approximately 40". Furthermore, the positions of the pressure indicators 33, 33' in relation to the top loop and the adjustment means 38, 38a have been indicated in the figure. Otherwise, reference is made to the figures described above.

The invention is not limited to the embodiment shown above as an example but can be subject to modifications within the scope of the following patent claims and the inventive concept.

Claims (5)

10 15 20 25 30 528 895 12 PATENT REQUIREMENTS 1. 1. Vehicle shock absorber (shock absorber 1) with optional 61161 OIIISTäÜÜ fl In the case of impact force character which is substantially independent of other internal or external functional factor in the damper and including one with fastening means (15, 15 "), which enables connecting parts to mutually movable parts the vehicle, provided with enclosing, piston and piston rod arrangements (2, 3, 7, 8) which comprise a working member (17), consisting of valves and connections, which in the event of damping force on the piston of the arrangement in its respective direction of movement causes a pressure increase at the piston the side facing the direction of movement while the pressure retainer is present at the side facing the piston fi at the direction of movement, a pressure guaranteeing means (22) at the same time substantially maintains the pressure in the arrangement in the event of pressure-acting parameters striving to change the pressure and the piston rod 8 (piston rod 8). arranged continuously and sealed in two ends (12 "12") or in a gable (37) and a wall in the arrangement by means of two seals / sealing elements (35a, 36a) than indicated by the fact that a gas separating piston (23, 45) included in the pressure-guaranteed member (22) is placed outside the path of movement of the current piston rod or piston rod elements (8, 8b) and is internally sealed with a seal (32) against one of the fastening means (15), which is constituted by a top loop (l5 ”). 2. A damper according to claim 1, characterized in that the top loop (15 ') is separate from the piston rod arrangement (8, 8b). A damper according to claim 2, characterized in that the top loop (15 ') has a sealing part (1a) and a cylindrical part (15b), against the outside of which said seals (3 1, 32 and 32 ") act. Damper according to claim 3, characterized in that a part of the piston rod (8) or the piston rod element (8b) is arranged to be able to run inside a recess (15c) sealed against the damper head (30) in the cylindrical part (15b) in the top loop. (15 ') at the movements of the piston (7). 528 8953 13 Damper according to one of the preceding claims, characterized in that the top loop (15 ') can be rotated about its longitudinal axis (53) and locked in any direction of rotation along the longitudinal axis (53) by means of a container end (63) arranged in connection with the damper head. (30), screwed outwards against a lock (65).