FR2565648A1 - ADJUSTABLE HYDRAULIC SHOCK ABSORBER - Google Patents

Abstract

IN THIS SHOCK ABSORBER, TO ADJUST THE SHOCK ABSORBING FORCES, PISTON 1 PRESENTS ON THE SIDE DIRECTED TO THE VALVES OF THE COMPRESSION PHASE AND, POSSIBLY, ON THE OPPOSITE SIDE, AT LEAST ONE RECESS 4 THAT COMMUNICATES WITH THE CAVITY OF THE HOLLOW PISTON ROD 7 THROUGH A FLOW DRILL 9 OR AN INLET DRILL 15. THE EXTENSION AND COMPRESSION DAMPING VALVES 3 MAY BE INFLUENCED THROUGH A LINK CHANNEL 32, OF CROSS BORING 8 LOCATED ABOVE THE PISTON AND A VALVE 21 LOCATED BELOW THE PISTON ROD. WE ARE LOOKING TO OBTAIN A MODIFICATION OF THE DAMPING FORCES AT LOW AND MEDIUM SPEEDS OF THE PISTON.

Description

1i 2565648

  The invention relates to a hydraulic damper

  adjustable valve comprising a damping piston attached to a hollow piston rod and dividing the cylinder of

  working in two half-chambers filled with amorphous liquid

  and optionally an additional pneumatic chamber, this piston having at least one damping valve for each of the extension phases and

  of compression, and in which the upper half-chamber

  re is placed in communication with the lower working chamber by a transverse bore located above the damping piston and by the internal cavity of the piston rod, while for the adjustment of the damping force, a rod is of control is arranged movable in axial translation in the interior cavity

of the piston rod.

  Shocks of this kind are known (for example, German Patent Application No. 32 41 984), which have an adjustment mechanism placed above the piston rod and serving to vary the section of the piston. a bypass passage located in

  the piston region. This device does not essentially determine

  a modification of the damping forces only in the lower range of the piston speeds. Moreover, for reasons of available space, it is

  almost impossible to stay in a motor vehicle

  a control device of this kind

the axial direction.

  Shocks are also known (for example, R.F.A. patent 29 11 768) in which

  the two half-chambers delimited by the piston of amor-

  are connected by an additional adjustable bypass passage. This is also

  in the case of this device, to act on the force of amor-

  in the lower speed range of the pistons

your.

  Based on this state of affairs, the purpose of

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  the invention is to give a damper a configura-

  such that it is possible to adjust the forces

  of damping in the lower range and in the

  piston piston and to act directly on at least one of the damping valves in a

  simple, without additional elements.

  Furthermore, the object of the invention is to

  to make the shock absorber so that it is possible

  to adjust the damping forces in the lower range

  and in the average range of piston speeds by acting on the valves, both for the

  compression only for the extension phase.

  According to the invention, to solve this problem, the damping piston presents, on the directed side

  to the damping valve provided for the phase of ex-

  voltage, at least one recess which is connected to

  with the inner cavity of the piston rod by

a flow piercing.

  This brings the advantage of allowing

  strongly rely on the damping forces both in the lower and the middle range of

  piston speeds, without the need for

  make modifications to the existing damping damper. The adjustment of the damping forces in the lower range and the average range of the piston speeds is obtained in this case by a modification

  effective forces acting on the damping valve

himself.

  According to another embodiment of the invention,

  tion, the recesses are distributed regularly over the

  of the damping piston and each recess

  feels a flow piercing. The presence of several

  recesses, which are additionally charged by the pres-

  sion makes it possible to exert the desired action on the damping valve. Depending on the action or the variability

  wishes to obtain, one or more recesses are provided.

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  According to an important characteristic, it is

  sees as damping valve at least one spring-la-

  me who can isolate the recess from the half-chamber

  pool. This construction brings the advantage of allowing

  Depending on the position of the control rod, the effective forces of the leaf springs applied to the damping piston can be modified. These recesses allow the pressure to act on the leaf springs to a corresponding extent, so that the leaf springs are

  loaded on new surfaces, in addition to

  the expansion ports of the damping piston

  and that damping forces can be achieved

weaker.

  In a particularly advantageous embodiment, the control rod forms, in combination with the inner wall of the piston rod, a connecting channel in which the transverse bead and the flow bore open into the open position of the piston rod.

  the control rod. We can use in this con-

  truction a one-piece control rod that can be appropriately controlled in the upper region of the piston rod. This axial control of the piston rod can be effected without difficulty by mechanical, hydraulic or pneumatic means.

electromagnetic.

  According to another important characteristic,

  the end of the piston rod is closed on the half

  lower chamber by a flap. An advantageous embodiment of the invention provides that the valve is constituted by a compression spring and an element

  movable valve member, the movable member of the valve being

  puyé on a valve seat formed by the piston rod

  your. In one embodiment of the invention,

  the valve is arranged so as to work parallel-

  to the directici of compression or extension of

  4 -.ss4 damping tone. In this construction, he can

  advantageously be provided a bypass passage sup-

  which not only makes it possible to modify the damping forces in the extension phase but which, at the same time, offers a new possibility of vari-

  the action on the compres-

if we.

  According to the invention, for the adjustment in the pha-

  the damping piston has on the side directed towards the damping valve provided for the compression phase at least one recess which is placed in communication with the internal cavity of the

  piston rod by a finish drilling. This construction

  tion has the advantage of being able to vary

  the damping forces both in the

  lower than in the average speed range of the

  piston, not only in the extension phase but also

  in the compression phase. The setting of the

  these damping in the lower range and in the average range of the piston speeds is obtained here by

  modification of the areas loaded with the valves and

  the effective forces of the damping dampers of the extension phase and the phase

compression.

  According to another embodiment, the recess

  close to the compression valve communicates with a

  annular channel consisting of an annular groove. gRA-

  the presence of such an annular groove

  amortizing fart is charged, not only through

  the recess but also by the amorphous fluid

  present in the annular groove. According to the possibility of action or the desired variability, it is possible to use an annular groove of cross-section

bigger and smaller.

  According to an important characteristic, it is

  sees for the drilling of arrival a hollow elastic pin. An advantage of this construction is that

  that the elastic pin serves, on the one hand, to

  the flow bores of the piston rod and also the flow groove of the control rod with respect to the corresponding recesses provided in the

  damping piston. At the same time, the elastic pin

  Thanks to its hollow configuration,

flow.

  According to a particularly advantageous embodiment, there is provided between the internal cavity of the piston rod and the inlet bore a flow groove formed in the outer surface of the control rod and which is in communication with the piercing.

central of the control rod.

  Other features and advantages of the

  will be better understood when reading the description of

  The following description of several embodiments and with reference to the accompanying schematic drawings in which, Figure 1 shows a pneumatic pressure monotube damper provided with means of action on the extension phase;

  FIG. 2 represents a shock absorber in principle

  pe similar to that already shown in Figure 1,

  but with the difference that it is possible

  ble to act on the damping force in the extension phase and in the compression phase; FIG. 3 is a sectional view of a

  shock absorber equipped with means of action on the phase of ex-

voltage and the compression phase.

  The adjustable hydraulic damper shown in section in Figure 1 is essentially composed of the working cylinder 17, and the hollow piston rod 7

  at the end of which is fixed the damping piston

  1. The damping piston 1 divides the volume

  inside the working cylinder 17 in two half-chambers

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  and 6. The damping piston 1 is equipped with

depreciation pets 3.

  In the lower half-chamber 6 is provided a

  separator piston 18 which separates the pneumatic compartment

  than 19 of the half-chamber 6. In the upper region

  of the working cylinder 17 is arranged a guide 20 of

  piston which serves to form a tight seal on the

  piston rod 7 and guide the latter.

  The damping piston itself has, for the extension phase, extension orifices 2 and a damping valve 3 which is provided in the form of

  of leaf springs. It is planned additionally in the re-

  lower part of the damping piston 1 of the

  4 which are in communication with the upper half-chamber 5 through the flow bores 9, the connecting channel 13 and the transverse bores 8. The control rod 10 is disposed movable in axial translation in the inner cavity of the piston rod 7 and is sealingly mounted by means of a sealing ring 11. The throttled area 12 of the control rod 10 forms, in combination with the hollow piston rod, the connecting channel 13 which presents the shape of an annular channel surrounding the control rod. In the lower region of the piston rod 7, the chamber 22 is isolated from the lower half-chamber 6 with a seal

  sealed by a valve 21. This valve 21 is arranged in

  with the extension phase of the damping valve

  3 and the movable member of the valve bears on the hollow piston rod 7 via a spring

of compression 25.

  The action on damping forces is ob-

  held by the fact that the areas responsible for the

  of the damping valve 3, which are delimited by the extension orifices 2 of the damping piston 1,

  can be enlarged by recesses 4 oriented

  which can be added to these orifices. This leads to low damping forces as the oil flows from the upper half-chamber 5 to the lower half-chamber 6. The hollow piston rod 7 has transverse bores 8 and flow bores 9 The control rod 10 is movably mounted in axial translation in the hollow piston rod 7 and

  the seal is hermetically sealed by the sealing ring

  11. Between the inner surface of the piston rod

  hollow 7 and the throttled area 12 of the control rod

  of 10, the annular connecting channel 13 is formed.

  When the control rod 10 is lowered, the cor-

  don 14 of the control rod 10 closes the holes

  transversal 8, so that only the

  expansion ports 2 come into play as charged areas, resulting in larger

damping forces.

  To ensure the positioning of the flow bores 9 of the hollow piston rod 7 with respect to the recesses of the damping piston 1, a pin 15 is inserted into the hollow piston rod 7

  and which exits in a groove 16 of the piston of amor-

  1. That the leakage oil can not be

  pressure chamber 22, the valve 21 is

  during the extension phase in the presence of an over-

pressure.

  The invention can be applied not only to

  a monotube damper with pneumatic pressure but also

to twin-tube shocks.

  FIG. 2 shows a damping

  pneumatic pressure monotube which differs essentially from the damper of FIG. 1 only by the fact that the valve 21 works in parallel with the

  compression phase of the damping piston 1. The

  lower part of the control rod 10 is here provided

  of a central borehole 23 from which bore holes

  diaux 24 that open into the upper half-chamber

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  8. In the upper position of the control rod 10, the action of an additional bypass passage produces, in addition to the modification of the forces of the extension phase, also a modification. forces of the compression phase. In this case, the oil flows from

  the lower half-chamber 6 in the chamber 22, in step

  by the flapper 21 which is then raised, and from this

  room 22, it flows into the upper half-chamber

  5 through the central hole 23 and the radial drilling

  dial 24 as well as through the transverse bores 8.

  The adjustable hydraulic damper shown in section in Figure 3 is essentially composed of the working cylinder 17 and the hollow piston rod 2

  at the end of which is fixed the damping piston

  1. The damping piston 1 divides the volume

  The damping piston 1 is equipped with damping tongues 3 and 26. In this case, the damping valves 3 are used in the extension phase. and

  the damping valves 26 in the compression phase

  if we. In the lower half-chamber 6 is provided a

  separator piston 18 which isolates the pneumatic compartment

  than 19 of the half-chamber 6. In the upper region

  of the working cylinder 17 is arranged a guide 20 of

  piston which serves to form a tight seal on the

  piston rod 7 and guide the latter.

  The damping piston itself comprises, for the extension phase, extension orifices 2 and a damping valve 3 which is provided in the form of

  of leaf springs. In addition, there is provision in the

  interior of the damping piston 1 of the

  4 which are in communication with the upper half-chamber 5 through the flow bores 9, the

  connecting channel 32, the annular channel 33 and the holes

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  The control rod 10 is mounted automatically

  bile in axial translation in the inner cavity of the piston rod 7 and the seal is hermetically sealed by a sealing ring 11. In the lower region of the piston rod 7, the chamber 22 is isolated from the lower half-chamber 6 to seal by a valve 21. This valve 21 is arranged in parallel with the phase

  of the damping valve 3 and the motor element

  bile of this valve bears on the hollow piston rod.

  se 7 with interposition of the compression spring 25.

  The adjustment of the damping forces in the extension phase is obtained by the fact that the loaded areas of the leaf springs of the damping valve 3,

  which are formed by the extension orifices 2 of the piston

  damping tone 1, can be enlarged by

  radial recesses 4 which may be added thereto. This is

  low damping forces in the flow of

  oil from the upper half chamber 5 to half

  lower chamber 6. In the hollow piston rod 7, there are transverse bores 8 and flow bores 9. The control rod 10 is mounted to move axially in the hollow piston rod 7 and

  the seal is hermetically sealed by the sealing ring

  11. The annular channels 33 and 33 'and the canal

  link 22 formed in the control rod 10 are formed

  within the cavity of the hollow piston rod

  7. When the control rod 10 goes down, it masks

  transverse bores 8, so that only the sectional areas of the extension orifices 2 come into

  play as loaded surfaces, which has the effect of

  to create higher damping forces

Vees.

  For the compression phase, the piston of amor-

  1 has compression ports 27 and a damping valve 26 which is also provided in the form of leaf springs. In addition, it is

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  provided in the upper region of the damping piston

  1 a recess 29 which is in communication with the lower half-chamber 6 via the inlet bore 28, the flow groove 30, the central bore 23 and the valve 21. The recess 29 is in outraged

  in communication with an annular channel 31 by means of

  which the damping valve 26 can be loaded further

  floor. To form the arrival pierce 28, the goupil-

  the 15 is of hollow configuration. In addition, the pin 15 serves to position the flow bores 9 of the

  hollow piston rod 7 and also the flow groove

  30 of the control rod 10 relative to the recesses

  4 and 29 of the damping piston 1.

  The adjustment of the damping forces in the compression phase is obtained by the fact that the

  areas loaded with the leaf springs of the damping valve

  26, which are formed by the sectional areas of the compression ports 27 of the damping piston 1

  can be enlarged by a radial recess 29 complete

  the annular channel 31 and which may be added thereto. This leads to low damping forces as the oil stream flows from the lower half-chamber 6 to the upper half-chamber 5 as it passes through the

valve 21 which is then open.

  When the control rod 10 is lowered from the stroke "S", the transverse bores 8 formed in the piston rod 7 are closed and the valve 10 is

  blocked by the arrival at the stop of the control rod o10.

  In this switching position there is no additional oil passage to the damping valves, so that the damping forces

developed are larger.

  The axial control of the control rod 10,

  in the upper region, not representative of

  piston rod 7 can be ensured without

  ficulty mechanically, hydraulically, pneumatically or 11n. 2565648

  even electromagnetic.

  Of course, various modifications may be made by those skilled in the art to the device which

  just described as a non-limiting example.

  mitative without departing from the scope of the invention.

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REFERENCE LIST

  1 Damping piston 2 Expansion hole 3 Damping damper 4 Hollow Upper half-chamber 6 - Lower half-chamber 7 Piston rod 8 Cross drilling 9 Flow drilling Control rod 11 Sealing ring 12 Throttled area 13 Connecting channel 14 Cord Pin 16 Groove 17 Working cylinder 18 Separator piston 19 Pneumatic compartment Piston rod guide 21 Valve 22 Chamber 23 Central drilling 24 Radial drilling Compression spring

  26 Damping valve of the compression phase

  sionf 27 Compression Holes 28 Inlet Hole 29 Hollow Flow Groove 31 Annular Channel 32 Connecting Channel 33 Annular Channel

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* R E V E N D IC A T I ONS

  1 - Adjustable hydraulic damper comprising

  a damping piston attached to a hollow piston rod

  which divides the working cylinder into two half

  filled with damping liquid and, where appropriate,

  an additional pneumatic chamber, this piston having at least one damping valve

  for the extension phase and the compres-

  sion, and where the upper half-chamber is

  nication with the lower half-chamber by a transversal bore formed above the damping piston

  and by the internal cavity of the piston rod,

  as for the adjustment of the damping force, a control rod is movably mounted in axial translation in the internal cavity of the piston rod,

  characterized in that the damping piston (1) pre-

  on the side facing the damping damper

  (3) provided for the extension phase, at least one

  (4) which is in communication with the cavity

  piston rod (7) by means of a piercing

(9).

  2 - Damper according to claim 1, characterized

  in that the recesses (4) are distributed regularly

  firstly on the revolution of the damping piston (1) and in that each recess (4) has a bore

flow (9).

  3 - Damper according to claim 1, characterized

  in that it includes, as damping valve

  (3), at least one leaf spring which can isolate the

  (4) of the lower half-chamber (6).

  4 - Damper according to claim 1, characterized

  characterized in that the control rod (10) forms in combination

  with the inner wall of the piston rod (7),

  a connecting channel (13) in which the transverse drilling

  sal (8) and the flow hole (9) open into

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14 roo

  the open position of the control rod (10).

  Shock absorber according to Claim 1, characterized in that the end of the piston rod (7)

  is closed on the lower half-chamber (6) by a key

pet (21).

  6 - Damper according to claim 5, characterized

  characterized in that the valve (21) is constituted by a res-

  compression casting and a movable valve member, the movable member of the valve being pressed against a seat

  valve formed by the piston rod (7).

  7 - Damper according to claim 5, characterized

  characterized in that the valve (21) is arranged to work in parallel with the compression phase or

  with the extension phase of the damping piston (1).

  8 - Damper according to claim 1, characterized

  in that, on the side directed towards the damping valve (26) provided for the compression phase,

  the damping piston (1) has at least one recess

  ment (29) which is in communication with the cavity

  piston rod (7) via a

arrival drilling (28).

  9 - Shock absorber according to claim 8, characterized

  characterized in that the recesses (29) are connected between

  them by an annular channel (31) constituted by a groove

  annular ring and in that the damping valve (26)

  can be loaded by these recesses and this channel.

  Shock absorber according to claim 9,

  characterized in that a hollow pin is provided (25)

  as a finish drilling (28).

  11 - Shock absorber according to claim 10,

  characterized in that between the inner cavity of the piston rod (7) and the inlet bore (28) is provided

  a connecting groove (30) in the outer surface

  dull of the control rod (10) and which is in communi-

  cation with the central bore (23) of the control rod.

of (10).