DAMPER WITH RESERVOIR

Abstract

A damper (20), comprising: a main damper assembly (22), comprising: a damper tube (26) comprising a damping fluid, wherein the damper tube (26) defines a main fluid chamber (28); a piston rod (30) which is retractable and extendable in the damper tube (26); a main working piston (32) attached to the piston rod (30) which divides the main fluid chamber (28) into a piston rod side and a non-piston rod side; wherein an upper zone (48) is defined at one end of the main fluid chamber (28) and a lower zone (50) is defined at one end of the main fluid chamber (28) opposite the upper zone (48), and a middle zone (52) is defined between the upper zone and the lower zone (50); and a secondary damper arrangement (24) in fluid connection with the main damper arrangement (22), comprising: a secondary damper tube (26) defining a secondary fluid chamber (64); a secondary working piston (68) which is arranged in the secondary fluid chamber (64) and includes flow channels formed through it; wherein the main damper is configured such that when the main working piston (32) moves in the middle zone (52), fluid is caused to flow through the main working piston (32) and the secondary working piston (68) to generate a first damping force, and when the main working piston (32) moves either in the upper or the lower zone, fluid is caused to flow only through the main working piston (32) to generate a second damping force, the first damping force being less than the second damping force, wherein the secondary working piston (68) divides the secondary fluid chamber (64) into an upper volume (72) and a lower volume (74), and wherein a floating piston (66) is arranged in the lower volume (74), which divides the lower volume into a fluid chamber (82) of the lower volume and a gas chamber (84) of the lower volume.

Description

AREA

[0001] The present invention relates to vibration dampers for motor vehicles. BACKGROUND

[0002] When a vehicle encounters a bump in the road, springs in the vehicle's suspension system compress and rebound to absorb the impact. Since the springs tend to continue oscillating after the bump is overcome, this spring oscillation reduces the vehicle's road holding and ride comfort. A shock absorber is used to dampen and stop this spring oscillation, providing better control of the movement of the affected wheel(s) and the vehicle itself, resulting in improved road holding and ride comfort.

[0003] For shock absorbers, also known as dampers or vibration dampers, in motor vehicles, the overall length of the shock absorber should be as short as possible to accommodate the available space within the vehicle body. However, the stroke of the piston rod must be as long as possible to absorb vibrational energy (the product of damping force and stroke). Additionally, it is often desirable for vehicle shock absorbers to be designed to generate damping forces that change as a function of the shock absorber stroke. In particular, it is desirable to generate higher damping forces at the end ranges of the shock absorber stroke to better control the movement of the corresponding vehicle wheel when the shock absorber is nearly fully compressed and nearly fully extended.

[0004] Variable damping can be achieved in various ways in the field of dampers. For example, RCO (Rebound Cut-Off) and JCO (Jounce Cut-Off) components can provide specific position-dependent damping in conventional full-length damper configurations. However, shock absorbers with variable damping force inevitably require additional damper length compared to conventional dampers to accommodate the various elements for adjusting the damping force.

[0005] Therefore, there is a need to provide position-dependent damping that overcomes the disadvantages of current dampers. The present invention meets this need. SUMMARY

[0006] One aspect of the invention is a damper comprising a main damper assembly with a damper tube and a damping fluid, wherein the damper tube defines a main fluid chamber. A piston rod is retractable and extendable within the damper tube. A main working piston is attached to the piston rod and divides the main fluid chamber into a piston rod side and a non-piston rod side. The main working piston includes flow channels formed through the piston rod side and the non-piston rod side. An upper passage is formed through the damper tube. A lower passage is formed through the damper tube and is spaced apart from the upper passage. An upper zone is defined at one end of the main fluid chamber by the upper passage, and a lower zone is defined at one end of the main fluid chamber opposite the upper zone by the lower passage.A middle zone is defined between the upper and lower zones. A secondary damper assembly, fluidly connected to the main damper assembly, comprises a secondary damper tube that defines a secondary fluid chamber. A secondary working piston is fixed in position within the secondary fluid chamber and includes flow channels formed through it. The secondary working piston divides the secondary fluid chamber into an upper volume and a lower volume. A secondary upper passage is connected to the upper passage of the main damper assembly and the upper volume. A secondary lower passage is connected to the lower passage of the main damper assembly and the lower volume.The spacing between the upper and lower passages is configured such that when the main working piston moves in the central zone, fluid flows through both flow channels of the main working piston and the secondary working piston to generate a first damping force. When the main working piston moves in either the upper or lower zone, fluid flows only through the flow channels of the main working piston to generate a second damping force. The first damping force is less than the second damping force. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present invention is described in more detail below with reference to the exemplary figures. The invention is not limited to the exemplary embodiments. All features described and / or illustrated herein can be used alone or in combination in various embodiments of the invention. The features and advantages of different embodiments of the present invention will become apparent upon reading the following detailed description with reference to the accompanying drawings; the drawings show: Fig. 1 a cross-sectional view of a main damper arrangement according to the disclosure in an extended state; Fig. 2 a cross-sectional view of a damper reservoir according to the disclosure for use with the main damper arrangement of Fig. 1; Fig. 3 a cross-sectional view of the main damper assembly of Fig. 1 in a compressed state; Fig. 4 a cross-sectional view of a main damper arrangement and an attached damper reservoir according to the disclosure; and Fig. 5 a side view of a cap for use with the damper reservoir of the disclosure; Fig. 6 a cross-sectional view of the cap of Fig. 5; Fig. 7 a partial side view of the cap of Fig. 5. DETAILED DESCRIPTION

[0008] For descriptive purposes, the terms "upper," "lower," "right," "left," "vertical," "horizontal," "top," "bottom," "lateral," "longitudinal," and other terms of orientation or position and derivatives thereof refer to the invention as depicted in the figures. The term "configured" or "configuration" is to be understood as referring to a structural size and / or shape. It is understood that alternative variations and sequences of steps are possible with the invention, unless expressly stated otherwise. It is further understood that the specific systems and processes depicted in the accompanying drawings and described in the following description are merely illustrative examples of the invention. Thus, specific dimensions and other physical properties in connection with the examples disclosed herein are not to be construed as limitations.

[0009] An example of a damper 20 according to the disclosure is given in the combination of Fig. 1 and Fig. The damper 20 comprises two main elements: a main damper assembly 22 in fluid communication with a secondary damper assembly 24. The main damper assembly 22 is generally in the form of a monotube shock absorber and includes a damper tube 26. The damper tube 26 can be cylindrical or have any other suitable shape and can be made of any suitable material, such as metallic materials, steel, titanium, aluminum, composite materials, and combinations thereof. The damper tube 26 can include a bearing 42 for attaching the damper tube portion of the damper 20 to a vehicle (not shown). The damper tube 26 encloses a fluid space or main fluid chamber 28, which is at least partially filled with hydraulic fluid, such as oil. The main damper assembly 22, which is in Fig. Figure 1 shows that the main damper assembly 22 is in an extended state. In contrast, it is assumed that the main damper assembly 22, which is shown in Figure 1, is in an extended state. Fig. 3 is shown, in a compressed state.

[0010] A piston rod 30, one end of which is located in the main fluid chamber 28 and carries a main working piston 32, and the other end of which includes a bearing 34 configured for attachment to a vehicle. The rod 30 and the main working piston 32 are conventionally configured for stroke movement within the main fluid chamber 28. The main working piston 32 divides the main fluid chamber into a piston rod side, or first fluid chamber 36, and a non-piston rod side, or second fluid chamber 38.

[0011] The main working piston 32 is equipped with suitable flow channels and valve mechanisms 40, such as passages and disc valves, for controlling the fluid flow through the main working piston in a well-known manner. When the vehicle encounters an unevenness on the road surface it is driving on, the bearings 34, 42 are caused to move closer together and / or further apart, which in turn causes the piston rod 30 to move in the damper tube 26. This, in turn, causes the main working piston 32 to move back and forth in the main fluid chamber 28, forcing fluid through the flow channels and the valve mechanisms 40 to generate a damping force, as is well known.

[0012] The disclosed main damper arrangement 22 differs from conventional vibration dampers in that the damper tube 26 comprises a pair of spaced-apart passages 44, 46, which, for example, extend through the damper tube. The upper or first passage 44 is positioned such that, assuming the main working piston 32 is located centrally within the damper tube 26 between a fully compressed and a fully extended state, it communicates with the piston rod side 36 of the main fluid chamber 28. The lower or second passage 46 is positioned such that, assuming the main working piston 32 is located centrally within the damper tube 26 between a fully compressed and a fully extended state, it communicates with the non-piston rod side 38 of the main fluid chamber 28.

[0013] With reference to Fig. 1 and Fig. 3. It can be considered that the first and second passages 44, 46 define the main fluid chamber 28 into an upper zone 48 above the first passage, a lower zone 50 below the second passage, and a middle zone 52 located between the first and second passages, the terminology of the named features referring to the invention as illustrated in the figures. For example, the position of the main working piston 32 is in Fig. 1 as shown in the upper zone 48. The position of the main working piston 32 in Fig. According to the diagram, 3 is located in the lower zone 50.

[0014] The main damper assembly 22 additionally comprises an upper line 54 in fluid communication with the upper passage 48 and a lower line 56 in fluid communication with the lower passage 46. In the illustrated example, the upper and lower lines 54, 56 are located outside the damper tube 26. The lines 54, 56 can be flexible hydraulic tubes configured to transmit fluid pressure into and out of the main damper assembly 22. Alternatively, the lines 54, 56 can be rigid tubes made of metal or any suitable material.

[0015] Fig. Figure 2 shows the other part of the damper 20 of the present disclosure. In particular, it shows Fig. 2 a secondary damper assembly 24. In this example, the secondary damper assembly 24 is configured to communicate with the main damper assembly 22 via the upper and lower lines 54, 56. The main and secondary damper assemblies 22, 24 work together, as described in more detail here, to generate a variable damping force as a function of the position of the main working piston 32 in the main damper assembly 22.

[0016] The secondary damper assembly 24 comprises a secondary damper tube 62, the construction of which is similar to that of the damper tube 26 of the main damper assembly 22. The secondary damper tube 62 and an end cap 60, configured to close the secondary damper tube, together define a secondary fluid chamber 64.

[0017] The end cap 60 seals against the secondary damper tube 62. A secondary working piston 68 is fixedly connected to the end cap 60, thus defining its position within the secondary damper tube 62. The secondary working piston 68 can be fixed to the end cap 60, for example, by a conventional fastener or can be fixed in position in any suitable manner.

[0018] The secondary working piston 68 is provided with suitable flow channels and valve mechanisms 70, such as passages and disc valves, for controlling the fluid flow through the secondary working piston in a well-known manner. Since the secondary working piston 68 is fixed in position within the secondary damper tube 62, the fluid flow through the secondary working piston does not depend on the generation of different fluid pressures on opposite sides of the piston by movement of the piston in the secondary damper assembly 24, but rather on the presence of different fluid pressures on opposite sides of the piston from the main damper assembly 22, as will be explained in more detail below.

[0019] The secondary working piston 68 divides the secondary fluid chamber 64 into an upper volume 72 between the end cap 60 and the working piston 68, and a lower volume 74 on the side of the piston opposite the upper volume. A floating piston 66 can be arranged in the lower volume 74 and engage sealingly and movably with the secondary damper tube 62 to divide the lower volume into a fluid chamber 82 and a gas chamber 84. The use and function of a floating piston 66 in a single-tube damper arrangement is well known.

[0020] The upper volume 72 is in fluid communication with the upper line 54 and thus with the upper passage 44 of the main damper assembly 22. The fluid chamber 82 of the lower volume 74 is in fluid communication with the lower line 56 and thus with the lower passage 46 of the main damper assembly 22. It is understood that, depending on performance requirements, the connections of the various passages and volumes may be reversed with respect to those shown. For example, depending on which passage (44 or 46) is connected to the secondary upper passage 76, the secondary working piston 68 may act as a bottom valve.

[0021] Fluid flow from the upper conduit 54, which enters and exits the upper volume 72, flows through a secondary upper passage 76. Fluid flow from the lower conduit 56, which enters and exits the fluid chamber 82 of the lower volume, flows through a second lower passage 78.

[0022] When the main working piston 32 of the main damper assembly is positioned between the upper and lower passages 44, 46, i.e., in the central zone 52, any changes in its position within the damper tube 26 generate a differential pressure in the piston rod side chamber and the non-piston rod side chamber 36, 38. The direction of the pressure differential is a function of the direction of movement of the main working piston 32. The pressures thus generated are directed through the upper and lower passages 44, 46, the upper and lower channels 54, 56, and enter the secondary damper assembly 24 through the secondary upper and secondary lower passages 76, 78, respectively. The fluid pressures thus directed cause fluid to flow in one direction through the secondary working piston 68 from high to low pressure. Simultaneously with the flow of fluid through the secondary working piston 68, fluid is also allowed to flow through the main working piston 32.Thus, the combined area of ​​the flow passages 40, 70 is utilized when the main working piston 32 is operated in the central zone 52 of the main damper assembly. Fluid flow through the combined area 40, 70 generates a first damping force.

[0023] In contrast to the operation of the damper in the central zone 52, which produces a relatively low degree of damping, the damper 22 operates differently and produces a comparatively higher degree of damping force when the main working piston 32 moves to the end ranges of its stroke. When the working piston 32 moves in the upper zone 48 or the lower zone 50, the upper and lower passages 44, 46 are both connected to the same chamber and experience the same fluid pressure. In this operating state, there is no significant pressure differential across the two passages, and there is little or no resulting fluid flow into / out of the secondary damper assembly 24.Fluid can continue to flow into the secondary damper 24 when the volume of the piston rod 30 is introduced into the system, however, there is no resulting pressure differential across the secondary working piston 68, and thus fluid takes the path of least resistance (only through the lower passage 78) and does not contribute to the reduction of the damping force, which occurs when the main piston is in zone 52.

[0024] Accordingly, when the working piston 32 moves in the upper or lower zone 48, 50, the fluid flows only through the main working piston 32 and is not exposed to the area provided by the two flow channels in the main working piston. When it is in the upper or lower zone 48, 50, the degree of flow resistance in the operating state of the damper is correspondingly higher, since the area in the main working piston 32 is smaller relative to the combined area of ​​the main and secondary working pistons. Consequently, when the main working piston 32 is in the upper or lower zone 48, 50, stronger damping is generated, and the damper 20 exhibits the desired property of variable damping as a function of the stroke of the main working piston 32.

[0025] The operation of the damper 120 from Fig. 4 corresponds to that of the damper discussed above. However, the structural configuration of the main damper assembly 122 and the secondary damper assembly 124 corresponds to that of a "piggyback" damper. Thus, instead of the fluid connection of the secondary damper assembly 124 to the main damper assembly 122 via hydraulic hoses or pipes, for example, the secondary damper tube 162 of the secondary damper assembly is connected to the damper tube 126 of the main damper assembly in a side-by-side arrangement. The secondary damper tube 162 of the secondary damper assembly 124 can be connected directly to the damper tube 126 of the main damper assembly 122 or indirectly to it by means of a connecting flange, a clamp, or any suitable connection, frame member, or structural element 186, or several structural elements.The connecting flange 186 can be configured for the physical and / or fluid connection of the through-flow pair 144 and 176 to each other and of the through-flow pair 146 and 178 to each other.

[0026] In the illustrated damper 120, the upper passage 144 is aligned with and connected to the secondary upper passage 176, and the lower passage 146 is aligned with and connected to the secondary lower passage 178. In all other aspects, the damper 120 corresponds to Fig. 4 the damper 20 of Fig. 1-3. However, as in the example above, the orientation of the secondary damper tube 162 can be reversed, so that the upper passage 144 can be connected to the secondary lower passage 178 and the lower passage 146 can be connected to the secondary upper passage 176.

[0027] Fig. Figures 5-7 represent an alternative end cap 260 and an alternative means for fluidly connecting a main damper to a second damper as discussed above. In particular, the end cap 260 comprises a generally cylindrical body 286 and flanges 288 formed at one end thereof. The flanges are shaped and dimensioned to accommodate seals, such as O-rings (not shown), with the uppermost and smaller opening being shaped and dimensioned for a compression fitting to retain the end cap in the secondary tube, or alternatively, retention with a retaining ring (not shown) is also considered. An axial bore 290 is provided through the body 286 to receive a fastening means (not shown) for fixing a working piston (see, for example, Figure 5-7). Fig. 4) formed therein. A countersunk bore 292 is formed on an outer section of the bore 290 for receiving a hose via a connection, for example an SAE J1926 ORB-8 threaded connection. Fluid passages 294 fluidically connect the countersunk bore 292 to the inner fluid chamber of a secondary damper (see e.g. Fig. 1-4) to generate the same fluid flow as that from the secondary upper passage of the device according to Fig. 1-4 will be provided.

[0028] Although the invention has been illustrated and described in detail in the drawings and the description above, such illustration and description are intended to be descriptive or exemplary and not limiting. It is understood that changes and modifications may be made by those skilled in the art within the scope of the following claims. In particular, the present invention covers further embodiments with any combination of features from the various embodiments described above and below. Furthermore, statements made herein that describe the invention refer to one embodiment of the invention and not necessarily all embodiments.

[0029] The terms used in the claims should be interpreted in such a way that their interpretation, in the broadest sense, is consistent with the foregoing description. For example, the use of the article "a" or "the" when introducing an element should not be interpreted as excluding a plurality of elements. Likewise, the mention of "or" should be interpreted as inclusive, such that the mention of "A or B" does not exclude "A and B" unless it is clear from the context or the foregoing description that only one of A and B is intended. Furthermore, the mention of "at least one of A, B and C" should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise.Furthermore, the mention of "A, B and / or C" or "at least one of A, B or C" should be interpreted comprehensively as any single unit of the listed elements, e.g. A, any subset of the listed elements, e.g. A and B, or the entire list of elements A, B and C.

Claims

[1] A damper (20) comprising: a main damper assembly (22) comprising: a damper tube (26) comprising a damping fluid, the damper tube (26) defining a main fluid chamber (28); a piston rod (30) which is retractable and extendable in the damper tube (26); a main working piston (32) mounted on the piston rod (30) and dividing the main fluid chamber (28) into a piston rod side and a non-piston rod side; wherein an upper zone (48) is defined at one end of the main fluid chamber (28) and a lower zone (50) is defined at one end of the main fluid chamber (28) opposite the upper zone (48), and a middle zone (52) is defined between the upper zone and the lower zone (50); and a secondary damper assembly (24) in fluid communication with the main damper assembly (22), comprising: a secondary damper tube (26) defining a secondary fluid chamber (64); a secondary working piston (68) disposed in the secondary fluid chamber (64) and comprising flow channels formed therethrough; wherein the main damper is configured such that when the main working piston (32) moves in the middle zone (52), fluid is caused to flow through the main working piston (32) and the secondary working piston (68) to generate a first damping force, and when the main working piston (32) moves in either the upper or lower zone, fluid is caused to flow only through the main working piston (32) to generate a second damping force, the first damping force being less than the second damping force, the secondary working piston (68) dividing the secondary fluid chamber (64) into an upper volume (72) and a lower volume (74), and a floating piston (66) is disposed in the lower volume (74) dividing the lower volume into a fluid chamber (82) of the lower volume and a gas chamber (84) of the lower volume. [2] The damper (20) of claim 1, wherein the main damper assembly (22) includes brackets configured for attachment to a vehicle. [3] The damper (20) of claim 2, wherein the secondary damper assembly (24) is in fluid communication with the main damper assembly (22) via an upper conduit and a lower conduit. [4] The damper (20) of claim 2, wherein the secondary damper assembly (24) is configured as a backpack container. [5] The damper (20) of claim 4, wherein the secondary damper tube (26) is attached to the damper tube (26). [6] The damper (20) of claim 5, wherein the secondary damper tube (26) is mounted to the damper tube (26) in a side-by-side configuration. [7] The damper (20) of claim 1, comprising an upper passage and a lower passage, the upper and lower passages being formed through the damper tube (26) and defining a central zone (52) therebetween, the upper zone (48) being defined in the damper tube (26) at one end thereof and the lower zone (50) being defined in the damper tube (26) opposite the upper zone. [8] Damper (20) according to claim 1, wherein the secondary working piston is fixed in position in the secondary damper tube (26). [9] The damper (20) of claim 8, wherein the secondary working piston divides a secondary fluid chamber (64) of the secondary damper tube (26) into an upper volume on one side thereof and a lower volume on an opposite side thereof. [10] The damper (20) of claim 9, wherein the upper volume is in fluid communication with the upper zone and the lower volume is in fluid communication with the lower zone. [11] Damper (20) according to claim 10, wherein the fluid connection is through an upper conduit and a lower conduit. [12] The damper (20) of claim 10, further comprising an end cap closing the secondary damper tube (26) and defining the secondary fluid chamber (64) in the secondary damper tube (26). [13] The damper (20) of claim 12, wherein the upper conduit fluidly connects the upper zone (48) of the main damper assembly (22) to the upper volume of the secondary damper assembly. [14] A damper (20) comprising: a main damper assembly (22) comprising: a damper tube (26) comprising a damping fluid, wherein the damper tube (26) defines a main fluid chamber (28); a piston rod (30) which is retractable and extendable in the damper tube (26); a main working piston (32) mounted on the piston rod (30) and dividing the main fluid chamber (28) into a piston rod side and a non-piston rod side, the main working piston (32) including flow channels formed therethrough in communication with the piston rod side and the non-piston rod side; an upper passage (44) formed through the damper tube (26); a lower passage (46) formed through the damper tube (26) and spaced from the upper passage (44); wherein an upper zone (48) is defined at one end of the main fluid chamber (28) by the upper passage (44) and a lower zone (50) is defined at one end of the main fluid chamber (28) opposite the upper zone (48) by the lower passage (46), and a middle zone (52) is defined between the upper zone (48) and the lower zone (50); and a secondary damper assembly (24) in fluid communication with the main damper assembly (22), comprising: a secondary damper tube (26) defining a secondary fluid chamber (64); a secondary working piston (68) fixed in position in the secondary fluid chamber (64) and Flow channels formed therethrough, wherein the secondary working piston (68) divides the secondary fluid chamber (64) into an upper volume (72) and a lower volume (74) is divided; a secondary upper passage (76) communicating with the upper passage (44) of the main damper assembly (22) and the upper volume (72); and a secondary lower passage (78) communicating with the lower passage (46) of the main damper assembly (22) and the lower volume (74); wherein the distance between the upper passage (44) and the lower passage (46) is configured such that, when the main working piston (32) moves in the central zone (52), fluid is caused to flow through both flow channels of the main working piston (32) and the secondary working piston (68) to generate a first damping force; and when the main working piston (32) moves in either the upper or lower zone, fluid is caused to flow only through the flow channels of the main working piston (32) to generate a second damping force, the first damping force being less than the second damping force, and wherein a floating piston (66) is arranged in the lower volume (74) which divides the lower volume (74) into a lower volume fluid chamber (82) and a lower volume gas chamber (84).

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