Hydraulic damper and vehicle

Abstract

The present disclosure relates to a hydraulic damper and a vehicle. The hydraulic damper comprises a cylinder, a piston valve, a piston rod, and a frequency selection valve. The piston valve is arranged inside the cylinder and divides a chamber of the cylinder into a compression chamber and a rebound chamber. The piston rod passes through the rebound chamber and is connected to the piston valve, the other end of the piston rod extends out of the cylinder, a bypass channel is provided in the piston rod, and the bypass channel is communicated with the compression chamber. The frequency selection valve is located in the rebound chamber, the frequency selection valve is mounted on the piston rod and is spaced apart from the piston valve by a preset distance along the axial direction of the piston rod, and the frequency selection valve is communicated with the other end of the bypass channel. When an excitation frequency applied to the hydraulic damper is higher than a preset frequency, the frequency selection valve is opened so that the bypass channel is communicated with the rebound chamber, and when the excitation frequency applied to the hydraulic damper is lower than the preset frequency, the frequency selection valve is closed so as to block the communication between the bypass channel and the rebound chamber. The hydraulic damper of the present disclosure is beneficial to improving the structural strength of the piston rod, and can adaptively adjust damping on the basis of an external excitation frequency.

Description

Hydraulic dampers and vehicles

[0001] Cross-references to related applications

[0002] This disclosure is based on and claims priority to Chinese Patent Application No. 202411047201.7, filed on July 31, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of damper technology, and more specifically, to a hydraulic damper and a vehicle. Background Technology

[0004] For vehicles, electromechanical equipment, bridges, or high-rise buildings requiring vibration reduction, the strong randomness or nonlinearity of the excitation source necessitates that the damping performance of the corresponding vibration reduction equipment be automatically adjusted according to the actual excitation characteristics. Currently, the most common approach is to add an electronic control system. Based on the excitation conditions and vibration reduction performance requirements, the controller controls the opening of the damping orifice of the valve in the damping device, or controls the viscosity of the liquid in the damping device, to achieve the purpose of adjusting the performance of the damping device.

[0005] In related technologies, although there are solutions that involve setting a frequency valve on the damper so that the damper can adaptively adjust the damping according to the external excitation frequency, the frequency valve of the aforementioned damper is usually set in the compression chamber of the cylinder and located at the end of the piston. This not only limits the installation scenarios but also weakens the structural strength of the piston rod, resulting in poor performance. Summary of the Invention

[0006] This disclosure aims to at least partially address one of the technical problems in the related art.

[0007] Therefore, embodiments of this disclosure propose a hydraulic damper. The frequency-selective valve of this hydraulic damper helps to improve the structural strength of the piston rod, and the damping can be adaptively adjusted according to the external excitation frequency, resulting in better performance.

[0008] Embodiments of this disclosure also propose a vehicle.

[0009] The hydraulic damper of this disclosure includes: a cylinder; a piston valve disposed within the cylinder and dividing the cylinder chamber into a compression chamber and a recovery chamber, both of which are filled with oil, the piston valve being capable of sliding relative to the cylinder with damping; and a piston rod, one end of which passes through the recovery chamber and is connected to the piston valve, the other end of which extends outside the cylinder, a bypass passage being provided within the piston rod, one end of which communicates with the compression chamber. A frequency selective valve is located in the recovery chamber and is mounted on the piston rod, spaced a preset distance from the piston valve along the axial direction of the piston rod. The frequency selective valve is connected to the other end of the bypass channel. When the excitation frequency of the hydraulic damper is higher than the preset frequency, the frequency selective valve opens to allow the bypass channel to connect with the recovery chamber. When the excitation frequency of the hydraulic damper is lower than the preset frequency, the frequency selective valve closes to block the connection between the bypass channel and the recovery chamber.

[0010] According to the embodiments of the present disclosure, in the hydraulic damper, during compression and recovery of the hydraulic damper, the piston valve can slide relative to the cylinder with damping. When the excitation frequency of the hydraulic damper is higher than a preset frequency, the frequency selective valve can be opened to connect the bypass flow channel with the recovery chamber, thereby reducing the damping force when the piston valve slides and thus reducing the rigidity of the hydraulic damper. When the excitation frequency of the hydraulic damper is lower than the preset frequency, the frequency selective valve can be closed to block the connection between the bypass flow channel and the recovery chamber, thereby increasing the damping force when the piston valve slides and thus increasing the rigidity of the hydraulic damper. Therefore, the hydraulic damper of the embodiments of the present disclosure can adaptively adjust the damping according to the external excitation frequency, resulting in better performance.

[0011] On the other hand, compared to related technologies where the frequency selector valve is located in the compression chamber, the frequency selector valve of this disclosure is installed in the recovery chamber and is not installed at the end of the piston rod. In other words, the frequency selector valve of the hydraulic damper of the embodiment of this disclosure can be installed at any position on the piston rod in the recovery chamber, thereby improving the structural strength of the piston rod.

[0012] In some embodiments, the frequency selective valve includes a valve housing, a bypass valve, and a frequency selective component. The valve housing is fixedly sleeved on the piston rod. The bypass valve and the frequency selective component are both installed inside the valve housing. The valve housing has a first opening at one end adjacent to the piston valve and a second opening at the other end opposite to the piston valve. The bypass valve is arranged adjacent to the first opening, and the frequency selective component is arranged adjacent to the second opening. The bypass valve is movable along the axial direction of the piston rod. When the piston valve moves toward the recovery chamber, if the excitation frequency of the hydraulic damper is higher than a preset frequency, the frequency selective component can drive the bypass valve to separate from the valve housing, so that the first opening communicates with the bypass flow channel. If the excitation frequency of the hydraulic damper is lower than the preset frequency, the frequency selective component can drive the bypass valve to abut against the valve housing, so as to block the communication between the bypass flow channel and the first opening. When the piston valve moves toward the compression chamber, the bypass valve abuts against the valve housing, so as to block the communication between the bypass flow channel and the first opening.

[0013] In some embodiments, the frequency selection component includes a flexible diaphragm assembly and a frequency selection diaphragm assembly. A bypass valve plate is provided on the bypass valve, and the bypass valve plate and the valve housing define a bypass cavity communicating with the first opening. The flexible diaphragm assembly and the valve housing define a flexible cavity communicating with the second opening. One side of the flexible diaphragm assembly is fixedly connected to the valve housing, and the other side of the flexible diaphragm assembly is slidably sleeved on the piston rod. The frequency selection diaphragm assembly, the valve housing, and the flexible diaphragm assembly together define a frequency selection upper cavity. The frequency selection diaphragm assembly, the valve housing, and the bypass valve together define a... The frequency-selective lower chamber has a frequency-selective pinhole on the valve housing. The recovery chamber communicates with the frequency-selective upper chamber through the frequency-selective pinhole. One side of the frequency-selective membrane assembly is connected to the valve housing, and the other side of the frequency-selective membrane assembly is slidably sleeved on the piston rod and connected to the bypass valve. The inner wall of the frequency-selective membrane assembly and the outer wall of the piston rod define a bypass flow gap, one end of which communicates with the bypass channel. When the pressure in the flexible chamber is greater than the pressure in the frequency-selective upper chamber, the flexible membrane assembly moves toward the frequency-selective membrane assembly to block the other end of the bypass flow gap from communicating with the valve housing. The frequency-selective upper cavity is connected. When the pressure in the flexible cavity is less than or equal to the pressure in the frequency-selective upper cavity, the flexible membrane assembly moves away from the frequency-selective membrane assembly to connect the other end of the bypass flow gap to the frequency-selective upper cavity. When the pressure in the bypass cavity is greater than the pressure in the frequency-selective lower cavity and exceeds a preset threshold, the bypass valve plate can elastically deform to connect the bypass cavity to the frequency-selective lower cavity. When the pressure in the bypass cavity is less than or equal to the preset threshold, the bypass valve plate resets to block the connection between the bypass cavity and the frequency-selective lower cavity. When the pressure in the upper frequency-selective cavity is greater than the pressure in the lower frequency-selective cavity, the frequency-selective membrane assembly can drive the bypass valve to move toward the flexible membrane assembly, so that the first opening is connected to the bypass channel and the bypass cavity, blocking the other end of the bypass gap from connecting with the upper frequency-selective cavity. When the pressure in the lower frequency-selective cavity is less than or equal to the pressure in the upper frequency-selective cavity, the frequency-selective membrane assembly can drive the bypass valve to move away from the flexible membrane assembly, so as to block the first opening from connecting with the bypass channel and the bypass cavity, and connecting the other end of the bypass gap with the upper frequency-selective cavity.

[0014] In some embodiments, the flexible membrane assembly includes a flexible membrane and a flexible membrane slide. One side of the flexible membrane is connected to the valve housing, and the other side of the flexible membrane is connected to the flexible membrane slide. The flexible membrane slide is slidably sleeved on the piston rod. When the pressure in the flexible cavity is greater than the pressure in the frequency-selective upper cavity, the flexible membrane can elastically deform to move the flexible membrane slide toward the frequency-selective membrane assembly. When the pressure in the flexible cavity is less than or equal to the pressure in the frequency-selective upper cavity, the flexible membrane can reset to move the flexible membrane slide away from the frequency-selective membrane assembly.

[0015] In some embodiments, the frequency selective valve further includes a limiting plate, and both the limiting plate and the bypass valve plate are sleeved on the bypass valve. The limiting plate is located on the side of the bypass valve plate opposite to the first opening, and the radial outer side of the limiting plate and the radial outer side of the bypass valve plate are spaced apart by a predetermined distance along the axial direction of the piston rod.

[0016] In some embodiments, the frequency-selective membrane assembly includes a frequency-selective membrane and a frequency-selective membrane slide. One side of the frequency-selective membrane is connected to the valve housing, and the other side of the frequency-selective membrane is connected to the frequency-selective membrane slide. The frequency-selective membrane slide is slidably sleeved on the piston rod and defines the bypass flow gap with the piston rod. The frequency-selective membrane slide is connected to the bypass valve. When the pressure in the lower frequency-selective chamber is greater than that in the upper frequency-selective chamber, the frequency-selective membrane can elastically deform to move the frequency-selective membrane slide and the bypass valve toward the flexible membrane assembly. When the pressure in the lower frequency-selective chamber is less than or equal to the pressure in the upper frequency-selective chamber, the frequency-selective membrane can reset to move the frequency-selective membrane slide toward the bypass valve in a direction away from the flexible membrane.

[0017] In some embodiments, the valve housing includes a valve housing body, an upper valve cover, a lower valve cover, and a frequency-selective pinhole seat. The upper valve cover and the lower valve cover are respectively installed at both ends of the valve housing body along the axial direction of the piston rod. A first opening is provided in the lower valve cover, and a second opening is provided in the upper valve cover. The frequency-selective pinhole seat is detachably installed in the valve housing body. The extension direction of the frequency-selective pinhole is perpendicular to the axial direction of the piston rod. A portion of the frequency-selective pinhole is formed on the valve housing body, and another portion of the frequency-selective pinhole is formed on the frequency-selective pinhole seat.

[0018] In some embodiments, the upper valve cover and the valve housing body define a first clamping groove, one side of the flexible membrane is fixed in the first clamping groove, the flexible membrane assembly further includes a locking ring, the locking ring is sleeved outside the flexible membrane slide and defines a second clamping groove with the flexible membrane slide, and the other side of the flexible membrane is fixed in the second clamping groove.

[0019] In some embodiments, the hydraulic damper further includes a first limiting nut and a second limiting nut, the first limiting nut and the second limiting nut being respectively arranged on both sides of the frequency selective valve along the axial direction of the piston rod, the first limiting nut and the second limiting nut being threadedly connected to the piston rod and clamping the frequency selective valve.

[0020] A vehicle according to another embodiment of the present disclosure includes the hydraulic damper described in any one of the embodiments of the present disclosure. Attached Figure Description

[0021] Figure 1 is a cross-sectional view of a hydraulic damper according to an embodiment of the present disclosure.

[0022] Figure 2 is a partial schematic diagram of a hydraulic damper (in a stationary state) according to an embodiment of the present disclosure.

[0023] Figure 3 is a partial schematic diagram of a hydraulic damper (in the recovery process and in the first stage) according to an embodiment of the present disclosure.

[0024] Figure 4 is a partial schematic diagram of a hydraulic damper (in the recovery process and in the second stage) according to an embodiment of the present disclosure.

[0025] Figure 5 is a partial schematic diagram of a hydraulic damper (in the recovery process and in the third stage) according to an embodiment of the present disclosure.

[0026] Figure 6 is a partial schematic diagram of a hydraulic damper (in the recovery process and in the fourth stage) according to an embodiment of the present disclosure.

[0027] Figure 7 is a partial schematic diagram of a hydraulic damper (in the compression process) according to an embodiment of the present disclosure.

[0028] Figure 8 is a cross-sectional view of the frequency selector valve (with the upper valve cover, lower valve cover and flexible diaphragm assembly removed) of the hydraulic damper according to an embodiment of the present disclosure.

[0029] Figure 9 is a cross-sectional view of the flexible diaphragm assembly of the frequency-selective valve of the hydraulic damper according to an embodiment of the present disclosure.

[0030] Figure 10 is an overall cross-sectional view of the frequency selection valve of the hydraulic damper according to an embodiment of the present disclosure.

[0031] Figure 11 is an exploded view of the frequency selection valve of the hydraulic damper according to an embodiment of the present disclosure.

[0032] Figure 12 is an exploded view of a hydraulic damper according to an embodiment of this disclosure.

[0033] Figure 13 is an exploded view of some parts of the hydraulic damper according to an embodiment of the present disclosure.

[0034] Reference numerals: 1. Cylinder; 2. Piston valve; 21. Damping channel; 22. Piston valve plate; 3. Frequency selective valve; 31. Valve housing; 311. Lower valve cover; 3111. First opening; 312. Upper valve cover; 3121. Second opening; 313. Valve housing body; 3131. Frequency selective pinhole; 314. Frequency selective pinhole seat; 32. Bypass valve; 321. Bypass valve plate; 322. Limiting plate; 33. Frequency selective component; 331. Flexible membrane assembly; 3311. Flexible membrane; 3312. Flexible membrane slide; 3313. Locking ring; 332. Frequency selective membrane assembly; 3321. Frequency selective membrane; 3322. Frequency selective membrane slide; 3323. Support ring; 34. Sealing ring; 4. Piston rod; 41. Bypass flow channel; 42. Bypass flow gap; 51. First limiting nut; 52. Second limiting nut; 61. Connecting seat; 62. Outer buffer block; 63. Front end cover; 64. Inner buffer block; 65. Nitrogen cylinder assembly; 66. Fixing nut; P1. Restoration chamber; P2. Flexible chamber; P3. Frequency selective upper chamber; P4. Frequency selective lower chamber; P5. Bypass chamber; P6. Compression chamber. Detailed Implementation

[0035] Embodiments of this disclosure are described in detail below, with examples of these embodiments illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this disclosure, and should not be construed as limiting it.

[0036] The hydraulic damper and vehicle according to embodiments of the present disclosure are described below with reference to Figures 1 to 13.

[0037] As shown in Figures 1 to 13, the hydraulic damper of this embodiment includes: cylinder 1, piston valve 2, piston rod 4, and frequency selector valve 3.

[0038] Piston valve 2 is located inside cylinder 1, dividing the cylinder 1 into a compression chamber P6 and a recovery chamber P1. Both compression chamber P6 and recovery chamber P1 are filled with oil. Piston valve 2 can slide relative to cylinder 1 with damping. One end of piston rod 4 (the lower end of piston rod 4 in Figure 1) passes through recovery chamber P1 and is connected to piston valve 2. The other end of piston rod 4 (the lower end of piston rod 4 in Figure 1) extends outside cylinder 1. A bypass channel 41 is provided inside piston rod 4, and one end of bypass channel 41 is connected to compression chamber P6.

[0039] The frequency selective valve 3 is located in the recovery chamber P1 and is mounted on the piston rod 4. The frequency selective valve 3 is spaced from the piston valve 2 by a preset distance along the axial direction of the piston rod 4, and the frequency selective valve 3 is connected to the other end of the bypass channel 41. It should be noted that the preset distance can be designed according to the required stroke of the hydraulic damper, and this disclosure does not limit it.

[0040] When the excitation frequency of the hydraulic damper is higher than the preset frequency, the frequency selection valve 3 opens so that the bypass channel 41 can be connected to the recovery chamber P1. When the excitation frequency of the hydraulic damper is lower than the preset frequency, the frequency selection valve 3 closes so as to block the connection between the bypass channel 41 and the recovery chamber P1.

[0041] According to the hydraulic damper of the embodiments of this disclosure, during compression and recovery of the hydraulic damper, the piston valve 2 can slide relative to the cylinder 1 with damping. When the excitation frequency of the hydraulic damper is higher than a preset frequency, the frequency selective valve 3 can be opened to connect the bypass flow channel 41 with the recovery chamber P1, thereby reducing the damping force when the piston valve 2 slides and thus reducing the rigidity of the hydraulic damper. When the excitation frequency of the hydraulic damper is lower than the preset frequency, the frequency selective valve 3 can be closed to block the connection between the bypass flow channel 41 and the recovery chamber P1, thereby increasing the damping force when the piston valve 2 slides and thus increasing the rigidity of the hydraulic damper. Therefore, the hydraulic damper of the embodiments of this disclosure can adaptively adjust the damping according to the external excitation frequency, resulting in better performance.

[0042] On the other hand, compared to the related art where the frequency selector valve 3 is located in the compression chamber P6, the frequency selector valve 3 of this disclosure is installed in the recovery chamber P1 and is not installed at the end of the piston rod 4. In other words, the frequency selector valve 3 of the hydraulic damper of the embodiment of this disclosure can be installed at any position of the piston rod 4 in the recovery chamber P1, thereby improving the structural strength of the piston rod 4.

[0043] It should be noted that piston valve 2 is used to isolate the recovery chamber P1 from the compression chamber P6. Piston valve 2 includes a damping channel 21 and a piston valve plate for opening and closing the damping channel 21. When the hydraulic damper is working, the corresponding damping valve plate can open, allowing oil to flow through the damping channel 21 between the recovery chamber P1 and the compression chamber P6, thus giving the hydraulic damper a large damping force. Piston valve 2 can also adopt other valve structures in related technologies, which are not limited in this disclosure.

[0044] As shown in Figure 2, the frequency selective valve 3 includes a valve housing 31, a bypass valve 32, and a frequency selective component 33. The valve housing 31 is fixedly sleeved on the piston rod 4. The bypass valve 32 and the frequency selective component 33 are both installed inside the valve housing 31. The valve housing 31 has a first opening 3111 at the end adjacent to the piston valve 2 and a second opening 3121 at the end opposite to the piston valve 2. The bypass valve 32 is arranged adjacent to the first opening 3111, and the frequency selective component 33 is arranged adjacent to the second opening 3121. The bypass valve 32 is movable along the axial direction of the piston rod 4. As shown in Figure 2, the first opening 3111 is located at the lower end of the valve housing 31 and communicates with the recovery chamber P1. The second opening 3121 is located at the upper end of the valve housing 31 and communicates with the recovery chamber P1. The frequency selective component 33 is located at the upper end of the bypass valve 32. When the frequency selective component 33 moves up and down under pressure, it can synchronously drive the bypass valve 32 to move up and down.

[0045] When the piston valve 2 moves toward the recovery chamber P1, if the excitation frequency of the hydraulic damper is higher than the preset frequency, the frequency selection component 33 can drive the bypass valve 32 to separate from the valve body 31 so that the first opening 3111 is connected to the bypass flow channel 41. If the excitation frequency of the hydraulic damper is lower than the preset frequency, the frequency selection component 33 can drive the bypass valve 32 to abut against the valve body 31 so as to block the connection between the bypass flow channel 41 and the first opening 3111.

[0046] Understandably, during the instant the hydraulic damper returns to its original state (i.e., the moment the piston rod 4 moves away from the compression chamber P6 and gradually extends out of the cylinder 1), the excitation frequency experienced by the hydraulic damper is higher than the preset frequency. At this time, the frequency selection component 33 of the frequency selection valve 3 can drive the bypass valve 32 to move upward to separate it from the valve body 31, thereby connecting the first opening 3111 with the bypass flow channel 41, thus reducing the rigidity of the hydraulic damper.

[0047] In a scenario where the hydraulic damper has recovered for a period of time, the excitation frequency experienced by the hydraulic damper is lower than the preset frequency. At this time, the frequency selection component 33 of the frequency selection valve 3 can drive the bypass valve 32 to move downward to abut against the valve body 31, thereby blocking the connection between the first opening 3111 and the bypass flow channel 41, thus increasing the rigidity of the hydraulic damper.

[0048] As shown in Figure 7, when the piston valve 2 moves toward the compression chamber P6, the bypass valve 32 abuts against the valve body 31 to block the connection between the bypass passage 41 and the first opening 3111. In other words, during the compression of the hydraulic damper, the bypass valve 32 is in a closed state to maintain a high damping force in the hydraulic damper and improve its performance.

[0049] Specifically, the frequency selection component 33 includes a flexible membrane assembly 331 and a frequency selection membrane assembly 332. A bypass valve plate 321 is provided on the bypass valve 32. The bypass valve plate 321 and the valve housing 31 define a bypass cavity P5 communicating with the first opening 3111. The flexible membrane assembly 331 and the valve housing 31 define a flexible cavity P2 communicating with the second opening 3121. One side of the flexible membrane assembly 331 is fixedly connected to the valve housing 31, and the other side of the flexible membrane assembly 331 is slidably sleeved on the piston rod 4. The frequency selection membrane assembly 332, the valve housing 31, and the flexible membrane assembly 331 together define the frequency selection... The frequency-selective lower cavity P4 is defined by the frequency-selective membrane assembly 332, the valve housing 31, and the bypass valve 32. The valve housing 31 is provided with a frequency-selective pinhole 3131. The restoration cavity P1 is connected to the frequency-selective upper cavity P3 through the frequency-selective pinhole 3131. One side (radially outer side) of the frequency-selective membrane assembly 332 is connected to the valve housing 31, and the other side (radially inner side) of the frequency-selective membrane assembly 332 is slidably sleeved on the piston rod 4 and connected to the bypass valve 32. The inner wall of the frequency-selective membrane assembly 332 and the outer wall of the piston rod 4 define a bypass flow gap 42. One end of the bypass flow gap 42 is connected to the bypass channel 41.

[0050] As shown in Figure 2, in the frequency selective valve 3, from top to bottom, the second opening 3121, flexible cavity P2, upper frequency selective cavity P3, lower frequency selective cavity P4, bypass valve 32, and first opening 3111 are arranged sequentially. Among them, the flexible membrane assembly 331 separates the flexible cavity P2 from the upper frequency selective cavity P3, the frequency selective membrane assembly 332 separates the upper frequency selective cavity P3 from the lower frequency selective cavity P4, and the bypass valve plate 321 separates the upper frequency selective cavity P3 from the bypass valve 32.

[0051] It should be noted that the frequency-selective upper cavity P3 is connected to the recovery cavity P1 through the frequency-selective pinhole 3131 (a slender strip hole). Due to the damping effect of the frequency-selective pinhole 3131, there is an instantaneous pressure difference between the frequency-selective upper cavity P3 and the recovery cavity P1 when the hydraulic damper is restored, and the pressure values ​​tend to be equal after a period of time.

[0052] When the pressure in the flexible cavity P2 is greater than the pressure in the frequency-selective upper cavity P3, the flexible membrane assembly 331 moves toward the frequency-selective membrane assembly 332 to block the other end of the bypass flow gap 42 from communicating with the frequency-selective upper cavity P3. When the pressure in the flexible cavity P2 is less than or equal to the pressure in the frequency-selective upper cavity P3, the flexible membrane assembly 331 moves away from the frequency-selective membrane assembly 332 to communicate with the other end of the bypass flow gap 42.

[0053] When the pressure in the bypass cavity P5 is greater than the pressure in the frequency-selective lower cavity P4 and exceeds a preset threshold, the bypass valve plate 321 can elastically deform to connect the bypass cavity P5 with the frequency-selective lower cavity P4. When the pressure in the bypass cavity P5 is less than or equal to the preset threshold, the bypass valve plate 321 resets to block the connection between the bypass cavity P5 and the frequency-selective lower cavity P4.

[0054] When the pressure in the lower frequency selective cavity P4 is greater than the pressure in the upper frequency selective cavity P3, the frequency selective membrane assembly 332 can drive the bypass valve 32 to move toward the flexible membrane assembly 331, so that the first opening 3111 is connected to the bypass channel 41 and the bypass cavity P5, blocking the other end of the bypass flow gap 42 from being connected to the upper frequency selective cavity P3. When the pressure in the lower frequency selective cavity P4 is less than or equal to the pressure in the upper frequency selective cavity P3, the frequency selective membrane assembly 332 can drive the bypass valve 32 to move away from the flexible membrane assembly 331, so as to block the first opening 3111 from being connected to the bypass channel 41 and the bypass cavity P5, and making the other end of the bypass flow gap 42 connected to the upper frequency selective cavity P3.

[0055] The hydraulic damper of this disclosure employs the above-described structural arrangement so that the bypass valve 32 opens only for a short period at the beginning of the piston rod 4's return stroke and closes after a certain flow rate of oil, with the flow requiring pressure differential and time. During the low-frequency excitation of the hydraulic damper, the frequency-selective upper chamber P3 reaches equilibrium pressure before contact during the return process, causing the frequency-selective diaphragm assembly 332 to reset and the bypass valve 32 to close, thereby enabling the hydraulic damper to generate rigid damping during the remaining return process.

[0056] When the hydraulic damper is under high-frequency excitation, the frequency-selective upper chamber P3 is still insufficient to reach equilibrium during a complete recovery process. This allows the bypass valve 32 to remain open during high-frequency excitation, thereby reducing the rigidity of the hydraulic damper.

[0057] As shown in Figure 2, when the hydraulic damper of the embodiment of this disclosure is in a stationary state, the pressures of the recovery chamber P1, flexible chamber P2, frequency-selective upper chamber P3, frequency-selective lower chamber P4, bypass chamber P5, and compression chamber P6 are equal. The flexible diaphragm assembly 331 is at the upper dead point (i.e., the limit position of the upward movement of the flexible diaphragm assembly 331), and the frequency-selective diaphragm assembly 332 is at the lower dead point (i.e., the limit position of the downward movement of the frequency-selective diaphragm assembly 332). At this time, the recovery chamber P1 is connected to the compression chamber P6 through the frequency-selective pinhole 3131, the frequency-selective lower chamber P4, the bypass flow gap 42, and the bypass flow channel 41.

[0058] As shown in Figures 3 to 6, the reset process of the hydraulic damper according to an embodiment of this disclosure is described in detail. Based on the order of reset time, the reset process of the hydraulic damper can be divided into a first stage, a second stage, a third stage, and a fourth stage.

[0059] In the first stage:

[0060] The piston rod 4 moves in the recovery direction (from bottom to top as shown in Figure 1). At this time, the pressure of the recovery chamber P1 is greater than the pressure of the compression chamber P6. The oil in the recovery chamber P1 flows into the compression chamber P6 through the piston valve 2, generating a large damping force.

[0061] Flexible cavity P2 is connected to restoration cavity P1, and the pressure of restoration cavity P1 is equal to the pressure of flexible cavity P2. Frequency selective upper cavity P3 is connected to restoration cavity P1 through frequency selective pinhole 3131. Since the gap of frequency selective pinhole 3131 is very small, the pressure change is delayed. Instantly, the pressure of restoration cavity P1 is greater than the pressure of frequency selective upper cavity P3, and then the pressure of flexible cavity P2 is greater than the pressure of frequency selective upper cavity P3.

[0062] The flexible membrane assembly 331 moves downward from the top dead center to contact the frequency selective membrane assembly 332, closing the connection between the frequency selective upper cavity P3 and the bypass flow gap 42, and continues to push the frequency selective membrane assembly 332 downward to close the bypass valve 32, blocking the connection between the bypass cavity P5 and the bypass flow channel 41. At the same time, it provides an instantaneous contact pressure to the bypass valve plate 321, blocking the connection between the bypass cavity P5 and the frequency selective lower cavity P4, so that the instantaneous pressure of the bypass cavity P5 is greater than the pressure of the frequency selective lower cavity P4.

[0063] In the second stage:

[0064] Since the pressure in the bypass chamber P5 is greater than the pressure in the frequency-selective lower chamber P4, and the threshold is reached, the bypass valve 321 opens. Oil flows from the bypass chamber P5 into the frequency-selective lower chamber P4, and after a short time, the pressure in the frequency-selective lower chamber P4 equals the pressure in the bypass chamber P5.

[0065] In the third stage:

[0066] Since the restoration cavity P1 is connected to the bypass cavity P5, the pressure of the restoration cavity P1 is equal to the pressure of the bypass cavity P5. Also, since the pressure of the frequency-selective lower cavity P4 is equal to the pressure of the bypass cavity P5, the pressure of the restoration cavity P1 is equal to the pressure of the frequency-selective lower cavity P4.

[0067] Because the oil enters the upper frequency selection cavity P3 through the frequency selection pinhole 3131 with a time delay, the pressure in the restoration cavity P1 is instantaneously greater than the pressure in the upper frequency selection cavity P3. Therefore, the pressure in the lower frequency selection cavity P4 is greater than the pressure in the upper frequency selection cavity P3.

[0068] Since the pressure in the lower frequency selective chamber P4 is greater than the pressure in the upper frequency selective chamber P3, the frequency selective diaphragm assembly 332 moves toward the upper frequency selective chamber P3, causing the bypass valve 32 to move upward and open. At this time, the bypass chamber P5 is connected to the bypass channel 41, and a large amount of oil from the restoration chamber P1 flows directly into the compression chamber P6 through the bypass chamber P5 and the bypass channel 41, reducing the flow rate of oil through the piston valve 2 and greatly reducing the damping force of the hydraulic damper.

[0069] In the fourth stage:

[0070] After the hydraulic damper has recovered for a period of time, the oil completely enters the upper frequency selection chamber P3, so that the pressure of the recovery chamber P1 equals the pressure of the upper frequency selection chamber P3. Therefore, the pressure of the flexible chamber P2 equals the pressure of the upper frequency selection chamber P3, which in turn equals the pressure of the lower frequency selection chamber P4.

[0071] Since the pressure of the flexible cavity P2 equals the pressure of the frequency-selective upper cavity P3 equals the pressure of the frequency-selective lower cavity P4, the flexible membrane assembly 331 and the frequency-selective membrane assembly 332 do not move. The flexible membrane assembly 331 is at the upper dead center, opening the bypass flow gap 42; the frequency-selective membrane assembly 332 is at the lower dead center, closing the bypass valve 32.

[0072] The recovery chamber P1 is connected to the compression chamber P6 through the frequency selection pinhole 3131, the frequency selection upper chamber P3, the bypass flow gap 42, and the bypass flow channel 41. Because the flow rate of the frequency selection pinhole 3131 is very low, only a small amount of oil flows from the recovery chamber P1 into the compression chamber P6 through the frequency selection pinhole 3131, the bypass flow gap 42, and the bypass flow channel 41. A large amount of oil still passes through the piston valve 2 to keep the hydraulic damper at a high damping force.

[0073] Figure 7 illustrates the compression process of the hydraulic damper in an embodiment of this disclosure.

[0074] The piston rod 4 moves in the compression direction (from top to bottom as shown in Figure 7). At this time, the pressure of the compression chamber P6 is greater than the pressure of the recovery chamber P1. The oil in the compression chamber P6 flows into the recovery chamber P1 through the piston valve 2, generating a large damping force.

[0075] The frequency selective upper cavity P3 is connected to the compression cavity P6 through the bypass flow gap 42 and the bypass flow channel 41. The pressure of the frequency selective upper cavity P3 is equal to the pressure of the compression cavity P6.

[0076] Because the flexible cavity P2, the bypass cavity P5, and the restoration cavity P1 are connected, the pressure of the restoration cavity P1 = the pressure of the flexible cavity P2 = the pressure of the frequency-selective lower cavity P4 = the pressure of the bypass cavity P5; therefore, the pressure of the flexible cavity P2 = the pressure of the frequency-selective lower cavity P4 < the pressure of the frequency-selective upper cavity P3. Thus, the flexible membrane assembly 331 is at the top dead center, and the bypass flow gap 42 is opened; the frequency-selective membrane assembly 332 is at the bottom dead center, and the bypass valve 32 is closed.

[0077] At this time, the compression chamber P6 is connected to the restoration chamber P1 through the bypass channel 41, bypass gap 42, and frequency-selective upper chamber P3. Since the flow rate of the frequency-selective pinhole 3131 is very low, only a small amount of oil flows from the compression chamber P6 into the restoration chamber P1 through the bypass channel 41, bypass gap 42, and frequency-selective upper chamber P3. A large amount of oil still passes through the piston valve 2 to keep the hydraulic damper at a high damping force.

[0078] In some embodiments, the flexible membrane assembly 331 includes a flexible membrane 3311 and a flexible membrane slide 3312. One side (radially outer side) of the flexible membrane 3311 is connected to the valve housing 31, and the other side (radially inner side) of the flexible membrane 3311 is connected to the flexible membrane slide 3312. The flexible membrane slide 3312 is slidably sleeved on the piston rod 4. When the pressure of the flexible cavity P2 is greater than the pressure of the frequency selective upper cavity P3, the flexible membrane 3311 can elastically deform so that the flexible membrane slide 3312 moves toward the frequency selective membrane assembly 332. When the pressure of the flexible cavity P2 is less than or equal to the pressure of the frequency selective upper cavity P3, the flexible membrane 3311 can be reset so that the flexible membrane slide 3312 moves toward the direction away from the frequency selective membrane assembly 332.

[0079] It is understood that when the flexible diaphragm 3311 deforms, one side of the flexible diaphragm 3311 can remain stationary with the valve housing 31, while the other side of the flexible diaphragm 3311 bends downwards to allow the flexible diaphragm slide 3312 to move downwards from the upper dead point to the lower dead point. The hydraulic damper of this disclosure, by configuring the flexible diaphragm assembly 331 with the above-described structure, simplifies the manufacturing of the flexible diaphragm assembly 331 and ensures reliable movement.

[0080] Furthermore, the frequency selective valve 3 also includes a limiting piece 322. Both the limiting piece 322 and the bypass valve piece 321 are fitted onto the bypass valve 32. The limiting piece 322 is located on the side of the bypass valve piece 321 opposite to the first opening 3111. The radial outer side of the limiting piece 322 and the radial outer side of the bypass valve piece 321 are spaced apart by a predetermined distance along the axial direction of the piston rod 4. It can be understood that the limiting piece 322 is located at the upper end of the bypass valve piece 321. Therefore, when the bypass valve piece 321 bends and deforms, the limiting piece 322 can stop it, preventing excessive deformation of the bypass valve piece 321 and ensuring the reliability of the bypass valve piece 321's operation.

[0081] Optionally, the frequency selective membrane assembly 332 includes a frequency selective membrane 3321 and a frequency selective membrane slide 3322. One side (radially outer) of the frequency selective membrane 3321 is connected to the valve housing 31, and the other side (radially inner) of the frequency selective membrane 3321 is connected to the frequency selective membrane slide 3322. The frequency selective membrane slide 3322 is slidably sleeved on the piston rod 4 and defines a bypass flow gap 42 with the piston rod 4. The frequency selective membrane slide 3322 is connected to the bypass valve 32. When the pressure in the lower frequency selective chamber P4 is greater than that in the upper frequency selective chamber P3, the frequency selective membrane 3321 can elastically deform to move the frequency selective membrane slide 3322 and the bypass valve 32 toward the flexible membrane assembly 331. When the pressure in the lower frequency selective chamber P4 is less than or equal to the pressure in the upper frequency selective chamber P3, the frequency selective membrane 3321 can be reset to move the frequency selective membrane slide 3322 toward the bypass valve 32 toward the direction away from the flexible membrane 3311.

[0082] It is understood that when the frequency-selective diaphragm 3321 deforms, one side of the diaphragm 3321 can remain stationary with the valve housing 31, while the other side of the diaphragm 3321 bends upwards, causing the frequency-selective diaphragm slide 3322 to move upwards from the lower dead center to the upper dead center. The hydraulic damper of this embodiment, by configuring the frequency-selective diaphragm assembly 332 with the above-described structure, simplifies the manufacturing process of the frequency-selective diaphragm assembly 332 and ensures reliable movement.

[0083] In some embodiments, as shown in Figures 8 to 10, the valve housing 31 includes a valve housing body 313, an upper valve cover 312, a lower valve cover 311, and a frequency-selective pinhole seat 314. The upper valve cover 312 and the lower valve cover 311 are respectively installed at both ends of the valve housing body 313 along the axial direction of the piston rod 4. A first opening 3111 is provided on the lower valve cover 311, and a second opening 3121 is provided on the upper valve cover 312. The frequency-selective pinhole seat 314 is detachably installed inside the valve housing body 313. The extension direction of the frequency-selective pinhole 3131 is perpendicular to the axial direction of the piston rod 4. Part of the frequency-selective pinhole 3131 is formed on the valve housing body 313, and another part of the frequency-selective pinhole 3131 is formed on the frequency-selective pinhole seat 314.

[0084] Understandably, the upper valve cover 312 is detachably mounted on the upper end of the valve body 313, and the lower valve cover 311 is detachably mounted on the lower end of the valve body 313. Since the frequency selection pin seat 314 is detachably mounted inside the valve body 313, the extension direction of the frequency selection pin 3131 is perpendicular to the axial direction of the piston rod 4. Part of the frequency selection pin 3131 is formed on the valve body 313, and the other part is formed on the frequency selection pin seat 314. This facilitates the assembly of the valve body 31 and extends the flow path of the frequency selection pin 3131. For example, there can be two frequency selection pins 3131, extending radially along the valve body 31 and symmetrically arranged on both sides of the valve body 31.

[0085] Specifically, the upper valve cover 312 and the valve body 313 define a first clamping groove. One side of the flexible membrane 3311 is fixed in the first clamping groove. The flexible membrane assembly 331 also includes a locking ring 3313, which is sleeved on the flexible membrane slide 3312 and defines a second clamping groove with the flexible membrane slide 3312. The other side of the flexible membrane 3311 is fixed in the second clamping groove. It can be understood that when the upper valve cover 312 and the valve body 313 are assembled, they can press and clamp the radially outer side of the flexible membrane 3311, and the locking ring 3313 is connected to the flexible membrane slide 3312 and presses the radially inner side of the flexible membrane 3311.

[0086] For example, sealing rings 34 can be provided at the upper and lower connection positions of the flexible diaphragm 3311. On the one hand, this can seal the flexible cavity P2 and provide a certain elastic pre-tightening force; on the other hand, it can prevent the flexible diaphragm 3311 from making hard contact with the upper valve cover 312 and the valve body 313, thereby extending the service life of the flexible diaphragm 3311. Furthermore, sealing rings 34 can also be provided between the upper valve cover 312 and the piston rod 4, and between the lower valve cover 311 and the piston rod 4, to improve the sealing effect of the frequency selective valve 3.

[0087] When the frequency selective pinhole seat 314 is installed with the valve cover body, it can clamp and fix the radial outer side of the frequency selective membrane 3321. The frequency selective membrane assembly 332 also includes a support ring 3323. The upper end face of the support ring 3323 abuts against the frequency selective membrane slide 3322 and clamps the radial inner side of the frequency selective membrane 3321. The lower end face of the support ring 3323 abuts against the limiting piece 322 to axially limit the limiting piece 322.

[0088] As shown in Figure 13, and in Figures 12 and 13, the hydraulic damper also includes a first limiting nut 51 and a second limiting nut 52. The first limiting nut 51 and the second limiting nut 52 are respectively arranged on both sides of the frequency selective valve 3 along the axial direction of the piston rod 4. The first limiting nut 51 and the second limiting nut 52 are threadedly connected to the piston rod 4 and clamp the frequency selective valve 3. This allows for axial limiting of the frequency selective valve 3, and facilitates installation and disassembly.

[0089] Specifically, as shown in Figures 12 and 13, the hydraulic damper also includes a connecting seat 61, an outer buffer block 62, a front end cover 63, and an inner buffer block 64. The connecting seat 61 is installed on the upper end of the piston rod 4. The outer buffer block 62 is sleeved on the piston rod 4 and arranged adjacent to the connecting seat 61. The front end cover 63 is installed on the cylinder 1 to seal the recovery chamber P1. The inner buffer block 64 is sleeved on the piston rod 4 and arranged adjacent to the frequency selector valve 3. The lower end of the piston valve 2 is provided with a fixing nut 66, which is threadedly connected to the piston rod 4, thereby axially limiting the piston valve 2.

[0090] In other examples, as shown in Figure 1, the hydraulic damper also includes a nitrogen cylinder assembly 65, which is installed outside the cylinder 1 and communicates with the compression chamber P6 to provide the piston rod 4 with restoring force and suppress oil vaporization, thereby improving the damping effect of the hydraulic damper.

[0091] The following describes the restoration process of a hydraulic damper according to a specific embodiment of this disclosure.

[0092] The reset process of the hydraulic damper is divided into four stages: the first stage, the second stage, the third stage, and the fourth stage.

[0093] In the first stage:

[0094] The piston rod 4 moves in the recovery direction (from bottom to top as shown in Figure 1). At this time, the pressure of the recovery chamber P1 is greater than the pressure of the compression chamber P6. The oil in the recovery chamber P1 flows into the compression chamber P6 through the piston valve 2, generating a large damping force.

[0095] Flexible cavity P2 is connected to restoration cavity P1, and the pressure of restoration cavity P1 is equal to the pressure of flexible cavity P2. Frequency selective upper cavity P3 is connected to restoration cavity P1 through frequency selective pinhole 3131. Since the gap of frequency selective pinhole 3131 is very small, the pressure change is delayed. Instantly, the pressure of restoration cavity P1 is greater than the pressure of frequency selective upper cavity P3, and then the pressure of flexible cavity P2 is greater than the pressure of frequency selective upper cavity P3. The flexible diaphragm 3311 bends and deforms towards the upper frequency selection cavity P3, causing the slide of the flexible diaphragm 3311 to move from the top dead center to contact the slide of the frequency selection diaphragm 3321, closing the connection between the upper frequency selection cavity P3 and the bypass flow gap 42, and continuing to push the slide of the frequency selection diaphragm 3321 downward, closing the bypass valve 32, blocking the connection between the bypass cavity P5 and the bypass flow channel 41, and at the same time providing an instantaneous contact pressure to the bypass valve plate 321, blocking the bypass cavity P5 and the lower frequency selection cavity P4, so that the instantaneous pressure of the bypass cavity P5 is greater than the pressure of the lower frequency selection cavity P4.

[0096] In the second stage:

[0097] Since the pressure in the bypass chamber P5 is greater than the pressure in the frequency-selective lower chamber P4, and the threshold is reached, the bypass valve 321 opens. Oil flows from the bypass chamber P5 into the frequency-selective lower chamber P4, and after a short time, the pressure in the frequency-selective lower chamber P4 equals the pressure in the bypass chamber P5.

[0098] In the third stage:

[0099] Since the restoration cavity P1 is connected to the bypass cavity P5, the pressure of the restoration cavity P1 is equal to the pressure of the bypass cavity P5. Also, since the pressure of the frequency-selective lower cavity P4 is equal to the pressure of the bypass cavity P5, the pressure of the restoration cavity P1 is equal to the pressure of the frequency-selective lower cavity P4.

[0100] Because the oil enters the upper frequency selection cavity P3 through the frequency selection pinhole 3131 with a time delay, the pressure in the restoration cavity P1 is instantaneously greater than the pressure in the upper frequency selection cavity P3. Therefore, the pressure in the lower frequency selection cavity P4 is greater than the pressure in the upper frequency selection cavity P3.

[0101] Since the pressure in the lower frequency selection chamber P4 is greater than the pressure in the upper frequency selection chamber P3, the frequency selection diaphragm 3321 bends and deforms towards the upper frequency selection chamber P3, causing the slide of the frequency selection diaphragm 3321 to move upward, opening the bypass valve 32. The bypass chamber P5 is connected to the bypass channel 41, and a large amount of oil in the restoration chamber P1 flows directly into the compression chamber P6 through the bypass chamber P5 and the bypass channel 41, reducing the flow rate of oil through the piston valve 2, which greatly reduces the damping force of the hydraulic damper.

[0102] In the fourth stage:

[0103] After the hydraulic damper has recovered for a period of time, the oil completely enters the upper frequency selection chamber P3, so that the pressure of the recovery chamber P1 equals the pressure of the upper frequency selection chamber P3. Therefore, the pressure of the flexible chamber P2 equals the pressure of the upper frequency selection chamber P3, which in turn equals the pressure of the lower frequency selection chamber P4.

[0104] Since the pressure of the flexible cavity P2 equals the pressure of the frequency-selective upper cavity P3 equals the pressure of the frequency-selective lower cavity P4, the flexible diaphragm 3311 and the frequency-selective diaphragm 3321 do not bend or deform. The slide of the flexible diaphragm 3311 is at the upper dead point, opening the bypass flow gap 42; the slide of the frequency-selective diaphragm 3321 is at the lower dead point, closing the bypass valve 32.

[0105] The recovery chamber P1 is connected to the compression chamber P6 through the frequency selection pinhole 3131, the frequency selection upper chamber P3, the bypass flow gap 42, and the bypass flow channel 41. Because the flow rate of the frequency selection pinhole 3131 is very low, only a small amount of oil flows from the recovery chamber P1 into the compression chamber P6 through the frequency selection pinhole 3131, the bypass flow gap 42, and the bypass flow channel 41. A large amount of oil still passes through the piston valve 2 to keep the hydraulic damper at a high damping force.

[0106] Therefore, it can be seen that the bypass valve 32 only opens at the moment the recovery stroke begins and closes after a certain flow rate. This flow requires pressure difference and time. During the low-frequency excitation of the hydraulic damper, the frequency-selective upper chamber P3 can reach the equilibrium pressure before the end of the recovery process, causing the frequency-selective diaphragm 3321 slide to return to its original position and the bypass valve 32 to close, thereby generating a strong damping force during the remaining recovery process; during the high-frequency excitation, the frequency-selective upper chamber P3 is still insufficient to reach equilibrium within a complete recovery process, causing the bypass valve 32 to remain open during the high-frequency excitation, thereby reducing the rigidity of the hydraulic damper.

[0107] Figure 7 illustrates the compression process of a hydraulic damper according to an embodiment of this disclosure.

[0108] Piston rod 4 moves in the compression direction (from top to bottom in Figure 7). At this time, the pressure in compression chamber P6 is greater than the pressure in recovery chamber P1. The oil in compression chamber P6 flows into recovery chamber P1 through piston valve 2, generating a large damping force. The frequency selective upper chamber P3 is connected to compression chamber P6 through bypass flow gap 42 and bypass flow channel 41. The pressure in frequency selective upper chamber P3 is equal to the pressure in compression chamber P6.

[0109] Since the flexible cavity P2, the bypass cavity P5, and the restoration cavity P1 are connected, the pressure of the restoration cavity P1 = the pressure of the flexible cavity P2 = the pressure of the frequency-selective lower cavity P4 = the pressure of the bypass cavity P5. Therefore, the pressure of the flexible cavity P2 = the pressure of the frequency-selective lower cavity P4 < the pressure of the frequency-selective upper cavity P3. As a result, the flexible diaphragm 3311 bends and deforms towards the flexible cavity P2, causing the slide of the flexible diaphragm 3311 to be at the upper dead point, thus opening the bypass flow gap 42. The frequency-selective diaphragm 3321 bends and deforms towards the frequency-selective lower cavity P4, causing the slide of the frequency-selective diaphragm 3321 to be at the lower dead point, thus closing the bypass valve 32.

[0110] At this time, the compression chamber P6 is connected to the restoration chamber P1 through the bypass channel 41, bypass gap 42, and frequency-selective upper chamber P3. Since the flow rate of the frequency-selective pinhole 3131 is very low, only a small amount of oil flows from the compression chamber P6 into the restoration chamber P1 through the bypass channel 41, bypass gap 42, and frequency-selective upper chamber P3. A large amount of oil still passes through the piston valve 2 to keep the hydraulic damper at a high damping force.

[0111] A vehicle according to another embodiment of this disclosure includes a hydraulic damper according to an embodiment of this disclosure. The technical advantages of the vehicle according to this disclosure are the same as those of the hydraulic damper in the above embodiments, and will not be repeated here.

[0112] In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0113] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0114] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0115] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0116] In this disclosure, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0117] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of this disclosure.

Claims

1. A hydraulic damper, comprising: Cylinder; A piston valve is disposed inside the cylinder and divides the cylinder chamber into a compression chamber and a recovery chamber. Both the compression chamber and the recovery chamber are filled with oil. The piston valve can slide relative to the cylinder with damping. A piston rod, one end of which passes through the recovery chamber and is connected to the piston valve, and the other end of which extends out of the cylinder. A bypass passage is provided inside the piston rod, and one end of the bypass passage is connected to the compression chamber. A frequency selective valve is located in the recovery chamber. The frequency selective valve is mounted on the piston rod and is spaced at a preset distance from the piston valve along the axial direction of the piston rod. The frequency selective valve is connected to the other end of the bypass channel. When the excitation frequency of the hydraulic damper is higher than the preset frequency, the frequency selective valve opens to allow the bypass channel to communicate with the recovery chamber. When the excitation frequency of the hydraulic damper is lower than the preset frequency, the frequency selective valve closes to block the communication between the bypass channel and the recovery chamber.

2. The hydraulic damper according to claim 1, wherein, The frequency selective valve includes a valve body, a bypass valve, and a frequency selective component. The valve body is fixedly sleeved on the piston rod. The bypass valve and the frequency selective component are both installed inside the valve body. The valve body has a first opening at one end adjacent to the piston valve and a second opening at one end opposite to the piston valve. The bypass valve is arranged adjacent to the first opening, and the frequency selective component is arranged adjacent to the second opening. The bypass valve is movable along the axial direction of the piston rod. When the piston valve moves toward the recovery chamber, if the excitation frequency of the hydraulic damper is higher than the preset frequency, the frequency selection component can drive the bypass valve to separate from the valve body so that the first opening is connected to the bypass flow channel. If the excitation frequency of the hydraulic damper is lower than the preset frequency, the frequency selection component can drive the bypass valve to abut against the valve body so as to block the connection between the bypass flow channel and the first opening. When the piston valve moves toward the compression chamber, the bypass valve abuts against the valve body to block the connection between the bypass passage and the first opening.

3. The hydraulic damper according to claim 2, wherein, The frequency selection component includes a flexible membrane assembly and a frequency selection membrane assembly. The bypass valve is provided with a bypass valve plate, which, together with the valve housing, defines a bypass cavity communicating with the first opening. The flexible membrane assembly, together with the valve housing, defines a flexible cavity communicating with the second opening. One side of the flexible membrane assembly is fixedly connected to the valve housing, and the other side of the flexible membrane assembly is slidably sleeved on the piston rod. The frequency selection membrane assembly, the valve housing, and the flexible membrane assembly together define a frequency selection upper cavity. The frequency selection membrane assembly, the valve housing, and the bypass valve together define a frequency selection lower cavity. The valve housing is provided with a frequency selection pinhole, and the recovery cavity communicates with the frequency selection upper cavity through the frequency selection pinhole. One side of the frequency selection membrane assembly is connected to the valve housing, and the other side of the frequency selection membrane assembly is slidably sleeved on the piston rod and connected to the bypass valve. The inner wall of the frequency selection membrane assembly and the outer wall of the piston rod define a bypass flow gap, and one end of the bypass flow gap communicates with the bypass channel. When the pressure in the flexible cavity is greater than the pressure in the frequency-selective upper cavity, the flexible membrane assembly moves toward the frequency-selective membrane assembly to block the other end of the bypass flow gap from communicating with the frequency-selective upper cavity. When the pressure in the flexible cavity is less than or equal to the pressure in the frequency-selective upper cavity, the flexible membrane assembly moves away from the frequency-selective membrane assembly to allow the other end of the bypass flow gap to communicate with the frequency-selective upper cavity. When the pressure in the bypass cavity is greater than the pressure in the frequency-selective lower cavity and exceeds a preset threshold, the bypass valve plate can be elastically deformed to connect the bypass cavity with the frequency-selective lower cavity. When the pressure in the bypass cavity is less than or equal to the preset threshold, the bypass valve plate resets to block the connection between the bypass cavity and the frequency-selective lower cavity. When the pressure in the lower frequency-selective cavity is greater than the pressure in the upper frequency-selective cavity, the frequency-selective membrane assembly can drive the bypass valve to move toward the flexible membrane assembly, so that the first opening communicates with the bypass channel and the bypass cavity, blocking the other end of the bypass flow gap from communicating with the upper frequency-selective cavity. When the pressure in the lower frequency-selective cavity is less than or equal to the pressure in the upper frequency-selective cavity, the frequency-selective membrane assembly can drive the bypass valve to move away from the flexible membrane assembly, so as to block the first opening from communicating with the bypass channel and the bypass cavity, and allowing the other end of the bypass flow gap to communicate with the upper frequency-selective cavity.

4. The hydraulic damper according to claim 3, wherein, The flexible membrane assembly includes a flexible membrane and a flexible membrane slide. One side of the flexible membrane is connected to the valve housing, and the other side of the flexible membrane is connected to the flexible membrane slide. The flexible membrane slide is slidably fitted onto the piston rod. When the pressure in the flexible cavity is greater than the pressure in the frequency-selective upper cavity, the flexible membrane can elastically deform to move the flexible membrane slide toward the frequency-selective membrane assembly. When the pressure in the flexible cavity is less than or equal to the pressure in the frequency-selective upper cavity, the flexible membrane can reset to move the flexible membrane slide away from the frequency-selective membrane assembly.

5. The hydraulic damper according to claim 1 or 2, wherein, The frequency selective valve also includes a limiting plate. Both the limiting plate and the bypass valve plate are sleeved on the bypass valve. The limiting plate is located on the side of the bypass valve plate opposite to the first opening. The radial outer side of the limiting plate and the radial outer side of the bypass valve plate are spaced apart by a predetermined distance along the axial direction of the piston rod.

6. The hydraulic damper according to claim 3 or 4, wherein, The frequency-selective membrane assembly includes a frequency-selective membrane and a frequency-selective membrane slide. One side of the frequency-selective membrane is connected to the valve housing, and the other side of the frequency-selective membrane is connected to the frequency-selective membrane slide. The frequency-selective membrane slide is slidably sleeved on the piston rod and defines the bypass flow gap with the piston rod. The frequency-selective membrane slide is connected to the bypass valve. When the pressure in the lower frequency-selective cavity is greater than that in the upper frequency-selective cavity, the frequency-selective membrane can elastically deform to move the frequency-selective membrane slide and the bypass valve toward the flexible membrane assembly. When the pressure in the lower frequency-selective cavity is less than or equal to the pressure in the upper frequency-selective cavity, the frequency-selective membrane can reset to move the frequency-selective membrane slide and the bypass valve away from the flexible membrane.

7. The hydraulic damper according to any one of claims 2-4 or claim 6, wherein, The valve housing includes a valve housing body, an upper valve cover, a lower valve cover, and a frequency-selective pinhole seat. The upper valve cover and the lower valve cover are respectively installed at both ends of the valve housing body along the axial direction of the piston rod. The first opening is located in the lower valve cover, and the second opening is located in the upper valve cover. The frequency-selective pinhole seat is detachably installed in the valve housing body. The extension direction of the frequency-selective pinhole is perpendicular to the axial direction of the piston rod. Part of the frequency-selective pinhole is formed on the valve housing body, and the other part of the frequency-selective pinhole is formed on the frequency-selective pinhole seat.

8. The hydraulic damper according to claim 7, wherein, The upper valve cover and the valve body define a first clamping groove. One side of the flexible membrane is fixed in the first clamping groove. The flexible membrane assembly also includes a locking ring. The locking ring is sleeved on the flexible membrane slide and defines a second clamping groove with the flexible membrane slide. The other side of the flexible membrane is fixed in the second clamping groove.

9. The hydraulic damper according to any one of claims 1-8, wherein, The hydraulic damper further includes a first limiting nut and a second limiting nut, which are respectively arranged on both sides of the frequency selective valve along the axial direction of the piston rod. The first limiting nut and the second limiting nut are threadedly connected to the piston rod and clamp the frequency selective valve.

10. A vehicle comprising the hydraulic damper according to any one of claims 1-9.

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