Hydraulic damper

Abstract

The invention provides a hydraulic damper. A damper assembly having a hydraulic compression stop (HCS) includes a tube defining an interior chamber. The damper assembly also includes a piston assembly slidably disposed in the tube. The piston assembly comprises an HCS piston and a safety valve assembly arranged on the top of the bottom valve. The relief valve assembly includes one or more deflection discs configured to deflect in response to a force applied to the piston rod exceeding a predetermined threshold, the deflection of the discs effecting a second working fluid flow from the HCS to the valve assembly, thereby reducing the force applied to the HCS.

Description

Technical Field

[0001] The present disclosure relates to a hydraulic damper, in particular to a motor vehicle suspension damper. Background Art

[0002] Certain vehicles include a suspension system provided with one or more hydraulic dampers. The hydraulic dampers may include a hydraulic compression stop assembly for generating additional damping force over a predetermined section of piston rod travel during a compression stroke. Summary of the invention

[0003] The present disclosure relates to a hydraulic damper for a vehicle. The hydraulic damper may include a main pipe, an outer pipe, a main piston assembly, a bottom valve assembly, and a hydraulic compression stop assembly. The main pipe may be filled with a hydraulic fluid, and the outer pipe may extend around the main pipe to define a compensation chamber. The main piston assembly may be disposed in the main pipe and may divide the main pipe into a rebound chamber and a compression chamber. The bottom valve assembly may be located at the end of the compression chamber to control the flow of a working fluid passing between the compression chamber and the compensation chamber. The hydraulic compression stop assembly may be disposed in the compression chamber and may include a safety valve assembly, a sleeve, and an additional piston assembly. The safety valve assembly may include a plurality of deflection discs and an adapter member. The safety valve assembly may be configured to change between a disengagement state and an engagement state. The sleeve may be fixed to the adapter member and configured to allow the working fluid to flow between the sleeve and the main pipe through the bottom valve assembly, and the sleeve may define an inner chamber. The additional piston assembly may be displaced with the main piston assembly and adapted to be introduced into the inner chamber of the insert at the end of the hydraulic damper compression stroke to generate an additional damping force, wherein the additional damping force is associated with the pressure applied to the safety valve assembly. In response to the associated pressure being below a predetermined threshold, the safety valve assembly may be in a disengaged state, in which the plurality of deflection discs are not deflected to enable a first working fluid flow from the inner chamber to the compression chamber, and the safety valve assembly may be in an engaged state, in which the plurality of deflection discs are deflected to enable a second working fluid flow from the safety valve assembly to the bottom valve assembly.

[0004] The adapter member may define a bore configured to communicate the flow of working fluid from the compression chamber to the plurality of deflection disks.

[0005] The safety valve assembly may include a plurality of spacers disposed between the bottom valve assembly and the plurality of deflection discs.

[0006] According to another aspect of the present disclosure, a hydraulic damper is provided. The hydraulic damper may include a main pipe, an outer pipe, a main piston assembly, a bottom valve assembly, and a hydraulic compression stop assembly. The main pipe may be filled with a working fluid, and the outer pipe may extend around the main pipe and may define a compensation chamber. The main piston assembly may include a main piston rod and may be slidably disposed in the main pipe and may divide the main pipe into a rebound chamber and a compression chamber. The bottom valve assembly may be located at the end of the compression chamber and configured to control the flow of the working fluid passing between the compression chamber and the compensation chamber, and the hydraulic compression stop assembly may be disposed in the compression chamber, and the hydraulic compression stop assembly may include a safety valve assembly, a sleeve, and an additional piston assembly. The additional piston assembly may include an additional piston rod, a piston ring, and a fastener, and the fastener may be configured to fix the piston ring to the additional piston rod. The additional piston assembly may be displaced with the main piston assembly, and may be configured to be introduced into the inner chamber of the insert at the end of the hydraulic damper compression stroke to generate an additional damping force. The additional damping force may be associated with the pressure applied to the safety valve assembly. In response to the associated pressure being lower than a predetermined threshold, the safety valve assembly is in a disengaged state to enable a first working fluid flow between the additional piston assembly and the inner chamber, and in response to the associated pressure rising above a predetermined threshold, the safety valve assembly is in an engaged state to enable a second working fluid flow from the safety valve assembly to the bottom valve assembly.

[0007] According to another aspect of the present disclosure, a hydraulic damper for a vehicle is provided. The hydraulic damper may include a main pipe, an outer pipe, a main piston assembly, a bottom valve assembly, and a hydraulic compression stop assembly. The main pipe may be filled with a working fluid, and the outer pipe may extend around the main pipe and may define a compensation chamber. The main piston assembly may include a main piston rod and may be slidably disposed in the main pipe and may divide the main pipe into a rebound chamber and a compression chamber. The hydraulic compression stop assembly may be located at the end of the compression chamber and may include a safety valve assembly, a sleeve, and an additional piston assembly. The safety valve assembly may be configured to change between a disengaged state and an engaged state, and the safety valve assembly may include a plurality of deflection discs, which may be configured to deflect to change the state of the safety valve assembly from a disengaged state to an engaged state. The additional piston assembly may include an additional piston rod, a piston ring, and a fastener. The fastener may be configured to fix the piston ring to the additional piston rod. The additional piston assembly may be displaced with the main piston assembly and is adapted to be introduced into the chamber of the insert at the end of the hydraulic damper compression stroke to generate an additional damping force. The pressure applied to the safety valve assembly may be based on the additional damping force. In response to the associated pressure being below a predetermined threshold, the safety valve may be in a disengaged state to enable a first working fluid flow between the additional piston assembly and the inner chamber. And in response to the associated pressure rising above the predetermined threshold, the safety valve assembly may be in an engaged state to enable a second working fluid flow from the safety valve assembly to the bottom valve assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A portion of a vehicle suspension including a damper according to one or more embodiments of the present disclosure is illustrated.

[0009] Figure 2 is a schematic cross-sectional view of an embodiment of a twin tube damper having an embodiment of a hydraulic compression stop assembly according to the present invention.

[0010] Figure 2A is along Figure 2 Detailed view taken along line 2A in FIG.

[0011] Figure 3 A perspective view of a sleeve of a hydraulic compression stop assembly is illustrated.

[0012] Figure 4 An exploded perspective view of an additional piston assembly is illustrated in accordance with one or more embodiments.

[0013] Figure 5 An exploded cross-sectional view of a safety valve assembly and a foot valve assembly of a hydraulic compression stop assembly is illustrated.

[0014] Figure 6A schematic cross-sectional view of an additional piston assembly and a hydraulic compression stop assembly is illustrated with the safety valve assembly in a disengaged state.

[0015] Figure 7 A schematic cross-sectional view of an additional piston assembly and a hydraulic compression stop assembly is illustrated with the safety valve assembly in an engaged state.

[0016] Fig. 7A The example shows Figure 7 Detailed view taken along line 7A in FIG. DETAILED DESCRIPTION

[0017] Embodiments of the present disclosure are described herein. However, it should be understood that the disclosed embodiments are merely examples, and other embodiments may take various and alternative forms. The drawings are not necessarily drawn to scale, and some features may be exaggerated or minimized to show the details of specific components. Therefore, the specific structural and functional details disclosed herein should not be interpreted as restrictive, but only as a representative basis for teaching those skilled in the art to adopt the embodiments in various ways. As will be understood by those of ordinary skill in the art, the various features illustrated and described with reference to any one of the accompanying drawings may be combined with the features illustrated in one or more other accompanying drawings to produce an embodiment that is not explicitly illustrated or described. The combination of the illustrated features provides a representative embodiment of a typical application. However, for a specific application or implementation, various combinations and modifications of features consistent with the teachings of the present disclosure may be desired.

[0018] The present invention is not limited to the specific embodiments and methods described below, as specific components and / or conditions may of course vary. Furthermore, the terminology used herein is for the purpose of describing specific embodiments of the present invention only, and is not intended to be limiting in any way.

[0019] As used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, reference to a component in the singular is intended to include a plurality of components.

[0020] The terms "substantially" or "about" may be used herein to describe the disclosed or claimed embodiments. The terms "substantially" or "about" may modify a value or relative property disclosed or claimed in the present disclosure. In such cases, "substantially" or "about" may mean that the value or relative property it modifies is within ±0%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, or 10% of the value or relative property.

[0021] When an element or layer is referred to as being "on," "engaged to," "connected to," or "coupled to" another element or layer, it may be directly on, engaged, connected, or coupled to that other element or layer, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). The term "and / or" includes any and all combinations of one or more of the associated listed items.

[0022] Although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Terms such as "first", "second" and other numerical terms do not imply order or sequence when used in this article unless the context clearly indicates. Therefore, without departing from the teaching of the example embodiments, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section.

[0023] For ease of description, spatially relative terms such as "inside," "outside," "below," "below," "lower," "above," "upper," etc. may be used to describe the relationship of one element or feature to another element or feature as illustrated in the figure. In addition to the orientation depicted in the accompanying drawings, spatially relative terms may be intended to cover different orientations of the device in use or operation. For example, if the device in the figure is turned over, an element described as being "below" or "beneath" another element or feature would then be oriented "above" the other element or feature. Thus, the example term "below" may cover both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.

[0024] Damper assemblies are well known in the art for use in vehicles. Vehicle suspension systems are designed to absorb shocks caused by uneven driving surfaces. Damper assemblies assist the suspension system by capturing vibrations between the wheels and the vehicle body. Dampers typically work in conjunction with springs, with the dampers absorbing excess forces that the springs can transfer to the vehicle body. Over rough roads, especially around curves, vibrations in the vehicle body can become severe enough to cause the driver to lose control of the vehicle. Once the wheels have passed over the bumpy area, the damper assembly dampens the main spring oscillations. The spring energy is converted to heat and dissipated by the damper. Early dampers were simply cylinders filled with oil or gas; damper designs have since improved.

[0025] In some designs, the damper assembly may provide enhanced damping characteristics using a hydraulic compression stop that generates additional damping force over a predefined end section of the piston rod's operating travel range. An exemplary damper provided with such a hydraulic compression stop is disclosed in the patent publication. The hydraulic compression stop gradually generates additional damping force depending not only on the piston assembly position but also on its velocity within the predefined end section (which may be tunable).

[0026] However, such hydraulic compression stops may limit the piston stroke length by using space within the damper that would otherwise be available for piston stroke.

[0027] Figure 1 A portion of an exemplary vehicle suspension including a damper 26 of the present disclosure is schematically illustrated, attached to a vehicle chassis 10 via a top mount 20 and a plurality of screws 18 disposed on the periphery of an upper surface of the top mount 20. The top mount 20 is connected to a coil spring 22 and a piston rod 24 of the damper 26. The tube 12 of the damper 26 is connected to a steering knuckle 14 supporting a wheel 16.

[0028] Figure 2 An embodiment of a twin tube damper 26 according to the present disclosure is shown, and Figure 2A Shown along Figure 2 Detailed view taken along line 2A in FIG. The damper 26 may include an outer tube 28 and a main tube 30 filled with a viscous working fluid, inside which a first or main movable rebound stop 32 is disposed, the first or main movable rebound stop 32 being attached to a main piston rod 24 which leads to the outside of the damper 26 through a sealed piston guide. The damper 26 is also provided with a bottom valve assembly 54 fixed at the other end of the main tube 30. The rebound stop 32 is slidably fitted with the inner surface of the main tube 30 and divides the tube 30 into a rebound chamber 34 and a rebound chamber 36. An additional compensation chamber 38 is located on the other side of the bottom valve assembly 54.

[0029] The damper 26 is further provided with a hydraulic compression stop assembly (HCS) 48 located in the rebound chamber 36 to generate additional damping force at the end of the compression stroke, for example, to avoid sudden stops of the rebound stop 32. The main components of the HCS 48 may include a sleeve 50, an adapter 52, and the piston assembly 40. Figure 4 As shown, the piston assembly 40 may include a second piston rod 42, a piston ring 46, and a fastener (e.g., a snap ring 44) configured to secure the piston ring 46 to the second piston rod 42. The second piston rod 42 may include a proximal portion 56, a distal portion 60, and an intermediate portion 58 extending between the proximal portion 56 and the distal portion 60. The proximal portion 56 may define a hole configured to receive a portion of the main piston rod 24 when the second piston assembly 40 moves with the rebound stop 32.

[0030] Figure 3 A perspective view of a sleeve 50 is shown, which may have a simple cylindrical shape and may be made of metal by cold drawing. As will be described in more detail below, the sleeve 50 includes an inner periphery 62 that may define one or more grooves 64 configured to facilitate flow of a working fluid from one end of the sleeve 50 to the other end of the sleeve 50.

[0031] Figure 4 4 shows an exploded perspective view of a piston assembly 40 according to one or more embodiments. As described above, the piston assembly 40 includes a second piston rod 42, a piston ring 46, and a fastener (e.g., a snap ring 44) configured to secure the piston ring 46 to the second piston rod 42. The piston rod 42 includes a proximal portion 56, a distal portion 60, and an intermediate portion 58 extending between the proximal portion 56 and the distal portion 60. The distal portion 60 may include a flange 55 and a groove 57, and the groove 57 may be disposed farther from the distal portion 60 than the flange 55. The piston ring 46 may be located on the flange 55, and the snap ring 44 may be inserted into the groove 57 to secure the piston ring 46 to the second piston rod 42 (e.g., on the flange 55). The snap ring may include one or more tabs 59 extending from the body of the snap ring 44, and the body may include opposite ends having end tabs 61, which may be spaced apart from each other so that the snap ring 44 may be inserted into the groove 57.

[0032] Figure 5An exploded perspective view of the adapter 52 and the bottom valve assembly 54 of the HCS 48 is illustrated. The bottom valve assembly 54 can include a bottom valve adapter 66, a bottom spacer 70, one or more disks, and a bottom valve top plate 72. The bottom valve adapter 66 can include an outer portion 102 and a center portion 104, which can be recessed or spaced apart from the outer portion 102. The center portion 104 can define a hole configured to receive the fastener 94. One or more (e.g., two) fluid passages 100 can be defined by the center portion 104 and disposed on either side of the fastener 94.

[0033] A plurality of bottom valve discs 68 and bottom valve spacers 70 may be centrally aligned by fasteners 94 such that the bottom valve discs 68 and spacers 70 are aligned with a center portion 104 of the bottom valve adapter 66. A bottom valve top plate 72 may be disposed on top of the bottom valve adapter 66, and one or more fluid passages 98 may be defined in the bottom valve top plate 72. The fluid passages 98 formed in the top plate 72 and the fluid passages 100 formed in the bottom valve adapter 66 may be configured to receive working fluid from the safety valve assembly 52 and provide the working fluid to the compensation chamber 38 ( Figure 2A ).

[0034] The safety valve assembly 52 may include a safety valve adapter member 84, one or more safety valve spacers 76, a top spacer 80, one or more deflection discs 78, an air inlet member 82, and a safety valve bottom plate 74. The safety valve adapter member 84 may include a first cylindrical portion 86 and a second cylindrical portion 88 that may circumferentially surround the first cylindrical portion 86. Upper portions of the first cylindrical portion 86 and the second cylindrical portion 88 may be spaced apart from each other to form a gap 108 that may accommodate an end portion of the sleeve 50. In one or more embodiments, a bottom portion 110 of the first cylindrical portion 86 may include one or more protrusions 112 that may be configured to engage and deflect the one or more deflection discs 78 in response to a pressure applied to the safety valve assembly 52 exceeding a predetermined threshold.

[0035] One or more safety valve spacers 76 may be disposed between the safety valve bottom plate 74 and the one or more deflection discs 78 to separate the bottom valve assembly 54 from the safety valve assembly 52. ​​The one or more safety valve spacers 76 may also be configured to apply a preload force to the one or more deflection discs 78. A top spacer 80 and an intake member fastener 82 (e.g., a nut) may be disposed in the central hole 90 defined by the first cylindrical portion. The intake member fastener 82 may define a hole 114 and a fluid passage provided with a first portion 116 and a second portion 118 extending from the hole 114. The first portion 116 of the fluid passage may be narrower than the second portion 118, and the first portion 116 and the second portion 118 may conduct the working fluid from the central hole 90 to the deflection disc 78.

[0036] Figure 6 A schematic cross-sectional view of the piston assembly 40 and the hydraulic compression stop assembly 48 is illustrated with the relief valve assembly 52 in a disengaged state. Figure 7 A schematic cross-sectional view of the additional piston assembly 40 and the hydraulic compression stop assembly 48 is illustrated with the relief valve assembly 52 in an engaged state. Fig. 7A The example shows Figure 7 Detailed view taken along line 7A in FIG.

[0037] like Figure 6 As shown, a first force F1 is applied to the second piston assembly 40 at a first speed V1. The force F1 may be less than a predetermined threshold (e.g., 1,000 N) applied at a speed of about 0.5 m / s, and the working fluid within the chamber 49 defined by the sleeve 50 may reach a first pressure P1 that may be insufficient to deflect one or more deflection discs 78. Because one or more deflection discs 78 are not deflected, some of the working fluid disposed in the chamber 49 may flow through the groove 64 and enter the compression chamber ( Figure 2 ), as indicated by the direction arrow FL1.

[0038] like Figure 7 and Fig. 7A As shown, the second force F2 can be applied to the piston assembly 40 at a second speed V2. The force F2 can be greater than a predetermined threshold (e.g., 1,000 N) applied at a speed of about 0.5 m / s or 1.0 m / s, and the working fluid disposed in the chamber 49 can reach a second pressure P2 (e.g., sufficient to deflect one or more deflection disks 78) Fig. 7AAs an example, the pressure P2 applies a force to the adapter member 84, and the protrusion 112 formed on the bottom of the adapter member 84 can apply a force to the deflection plate 78 to enable the second working fluid flow (as shown by the direction arrow FL2) to travel through the gap formed between the deflection plate 78 and one or more parts of the safety valve assembly 52 (e.g., the intake member 82) to reach the bottom valve assembly 54. The second fluid flow FL2 can reduce the pressure P2 in the chamber and reduce the force applied to the second piston rod 42 and inhibit possible damage to other components of the vehicle suspension system and the vehicle chassis.

[0039] Although exemplary embodiments are described above, these embodiments are not intended to describe all possible forms covered by the claims. The words used in the specification are descriptive rather than restrictive, and it should be understood that various changes can be made without departing from the spirit and scope of the present disclosure. As previously mentioned, the features of various embodiments can be combined to form other embodiments of the present invention that may not be clearly described or illustrated. Although various embodiments may have been described as providing advantages or being superior to other embodiments or prior art implementations in terms of one or more desired characteristics, it is recognized by those of ordinary skill in the art that one or more features or characteristics may be compromised to achieve the desired overall system properties, depending on the specific application and implementation. These properties may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, maintainability, weight, manufacturability, ease of assembly, etc. Therefore, to the extent that any embodiment is described as not as desirable as other embodiments or prior art implementations in terms of one or more characteristics, these embodiments do not exceed the scope of the present disclosure and may be desirable for a particular application.

Claims

1. A hydraulic damper, comprising: a main pipe filled with a working fluid; an outer tube extending around the main tube and defining a compensation chamber; a main piston assembly slidably disposed in the main pipe and dividing the main pipe into a rebound chamber and a compression chamber; a bottom valve assembly located at an end of the compression chamber to control the flow of a working fluid passing between the compression chamber and the compensation chamber; as well as a hydraulic compression stop assembly disposed in the compression chamber and comprising: A safety valve assembly comprising a plurality of deflection discs and an adapter member, the safety valve assembly being configured to change between a disengaged state and an engaged state, a sleeve fixed to the adapter member and configured to allow a working fluid to flow between the sleeve and the main pipe through the base valve assembly, the sleeve defining an inner chamber, and an additional piston assembly displaceable together with the main piston assembly and adapted to be introduced into the inner chamber of the sleeve at the end of a hydraulic damper compression stroke to generate an additional damping force, wherein the additional damping force is associated with a pressure applied to the safety valve assembly, wherein, in response to the associated pressure being lower than a predetermined threshold, the safety valve assembly is in the disengaged state, in which the plurality of deflection disks do not deflect to enable a first working fluid flow from the inner chamber to the compression chamber, and in response to the associated pressure rising above the predetermined threshold, the safety valve assembly is in the engaged state, in which the plurality of deflection disks deflect to enable a second working fluid flow from the safety valve assembly to the bottom valve assembly.

2. The hydraulic damper according to claim 1, wherein: The adapter member defines a bore configured to conduct working fluid flow from the compression chamber to the plurality of deflection disks.

3. The hydraulic damper according to claim 1, wherein: The safety valve assembly includes a plurality of spacers disposed between the bottom valve assembly and the plurality of deflection discs.

4. The hydraulic damper according to claim 3, wherein: The plurality of spacers are configured to apply a preload to the plurality of deflection disks.

5. The hydraulic damper according to claim 4, wherein: The plurality of spacers are configured to separate the safety valve assembly from the bottom valve assembly.

6. The hydraulic damper according to claim 1, wherein: The hydraulic compression stop assembly includes a fastening member provided with a first end and a second end, the first end including a head configured to engage the base valve assembly.

7. The hydraulic damper according to claim 6, wherein: The hydraulic compression stop assembly includes an intake retainer member, wherein the intake retainer member is secured to the second end of the fastening member.

8. The hydraulic damper according to claim 1, wherein: The adapter member includes a first cylindrical portion surrounding a second cylindrical portion, the second cylindrical portion defining a central bore configured to conduct working fluid flow from the compression chamber to the plurality of deflection disks.

9. The hydraulic damper according to claim 8, wherein: The first cylindrical portion is spaced apart from the second cylindrical portion to form a gap, wherein an end region of the sleeve is disposed within the gap.

10. The hydraulic damper according to claim 8, wherein: A bottom region of the second cylindrical portion defines one or more protrusions configured to engage and deflect the plurality of deflection discs to enable a second working fluid flow from the safety valve assembly to the base valve assembly.

11. The hydraulic damper according to claim 10, wherein: A bottom region of the first cylindrical portion covers at least a portion of the bottom valve assembly with respect to a radial direction.

12. The hydraulic damper according to claim 1, wherein: An inner periphery of the sleeve defines one or more grooves configured to facilitate flow of the first working fluid and flow of the second working fluid.

13. A hydraulic damper, comprising: a main pipe filled with a working fluid; an outer tube extending around the main tube and defining a compensation chamber; a main piston assembly including a main piston rod and slidably disposed in the main pipe and dividing the main pipe into a rebound chamber and a compression chamber; a bottom valve assembly located at an end of the compression chamber to control the flow of a working fluid passing between the compression chamber and the compensation chamber; as well as a hydraulic compression stop assembly disposed in the compression chamber and comprising: a safety valve assembly configured to change between a disengaged state and an engaged state, a sleeve fixed to the safety valve assembly and configured to allow fluid to flow between the sleeve and the main pipe through the base valve assembly, the sleeve defining an inner chamber, and an additional piston assembly comprising an additional piston rod, a piston ring and a fastener securing the piston ring to the additional piston rod, wherein the additional piston assembly is displaceable together with the main piston assembly and is adapted to be introduced into the inner chamber of the sleeve at the end of a compression stroke of the hydraulic damper to generate an additional damping force, wherein the additional damping force is associated with a pressure applied to the safety valve assembly, Wherein, in response to the associated pressure being lower than a predetermined threshold, the safety valve assembly is in the disengaged state to enable the flow of a first working fluid between the additional piston assembly and the inner chamber, and in response to the associated pressure rising above the predetermined threshold, the safety valve is in the engaged state to enable the flow of a second working fluid from the safety valve assembly to the bottom valve assembly.

14. The hydraulic damper according to claim 13, wherein: The safety valve assembly includes an adapter member and a plurality of deflection disks, wherein when the safety valve assembly is in the engaged state, the plurality of deflection disks deflect to allow the second working fluid to flow from the safety valve assembly to the base valve assembly.

15. The hydraulic damper according to claim 13, wherein: The additional piston rod is fixed to the main piston rod.

16. The hydraulic damper according to claim 15, wherein: The additional piston rod comprises a flange, wherein the piston ring is located on an axial face of the flange, wherein the axial face faces the safety valve assembly.

17. The hydraulic damper according to claim 16, wherein: The additional piston rod comprises a proximal portion, an intermediate portion and a distal portion, wherein the proximal portion is fixed to the main piston rod, and the distal portion comprises the flange and the recess, wherein the fastener is a snap ring fixed in the recess, and the piston ring is arranged between the flange and the snap ring.

18. A hydraulic damper, comprising: a main pipe filled with a working fluid; an outer tube extending around the main tube and defining a compensation chamber; a main piston assembly including a main piston rod and slidably disposed in the main pipe and dividing the main pipe into a rebound chamber and a compression chamber; a bottom valve assembly located at an end of the compression chamber to control the flow of a working fluid passing between the compression chamber and the compensation chamber; as well as a hydraulic compression stop assembly disposed in the compression chamber and comprising: a safety valve assembly configured to change between a disengaged state and an engaged state, the safety valve assembly comprising a plurality of deflection discs configured to deflect to change the state of the safety valve assembly from the disengaged state to the engaged state, a sleeve fixed to the safety valve assembly and configured to allow fluid to flow between the sleeve and the main pipe through the base valve assembly, the sleeve defining an inner chamber, and an additional piston assembly comprising an additional piston rod, a piston ring and a fastener securing the piston ring to the additional piston rod, wherein the additional piston assembly is displaceable together with the main piston assembly and is adapted to be introduced into the inner chamber of the sleeve at the end of a compression stroke of the hydraulic damper to generate an additional damping force, wherein the pressure applied to the safety valve assembly is based on the additional damping force, In which, in response to the pressure being lower than a predetermined threshold, the safety valve assembly is in the disengaged state to enable the flow of a first working fluid between the additional piston assembly and the inner chamber, and in response to the pressure rising above the predetermined threshold, the safety valve assembly is in the engaged state to enable the flow of a second working fluid from the safety valve assembly to the bottom valve assembly.

19. The hydraulic damper according to claim 18, wherein: The safety valve assembly further includes an adapter member and a plurality of spacers, wherein an end of the sleeve is disposed on the adapter member, and wherein the plurality of spacers are disposed between the bottom valve assembly and the plurality of deflection discs.

20. The hydraulic damper according to claim 18, wherein: The hydraulic compression stop assembly further includes a fastener provided with a head, wherein the base valve assembly is sandwiched between the head of the fastener and the safety valve assembly.

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