High speed extension controlled spring for bicycle seat adjustment

Abstract

The application relates to a high-speed stretching controllable spring for bicycle seat adjustment, which comprises a starting top rod, a hollow piston rod, a framework guide, a sealing ring, a pressurized air cavity, a positioning groove, a piston assembly, an oil cavity and a cylinder barrel, the cylinder barrel is divided into the pressurized air cavity and the oil cavity by the positioning groove, the framework guide is arranged at one end of the cylinder barrel, the sealing ring is arranged on one side of the framework guide, the piston assembly is arranged at one end of the oil cavity, one end of the hollow piston rod is connected with the piston assembly, the other end of the hollow piston rod penetrates through the framework guide and extends to the outside of the cylinder barrel, the starting top rod is arranged in the hollow piston rod in a penetrating mode, a piston valve needle is arranged in the piston assembly, and the piston valve needle is connected with the starting top rod; the application solves the problem of slow seat adjustment stretching speed, improves the adjustment response efficiency, reduces the product size, optimizes the installation adaptability, reduces the compression ratio and reduces the operation force change.

Description

Technical Field

[0001] This invention belongs to the field of gas spring technology, specifically a high-speed extension controllable spring for adjusting bicycle seats. Background Technology

[0002] Currently, controllable springs used for bicycle seat adjustment generally suffer from the following core problems, affecting riding experience and product reliability:

[0003] Insufficient support performance: The seat has weak support rigidity and is prone to slight wobbling during riding, making it unable to stably support the rider's weight, which can pose a safety hazard, especially on bumpy roads.

[0004] Slow dynamic response: The extension speed is low, and it takes a long time to adjust the seat height, resulting in low operating efficiency and inability to meet the needs of temporary adjustments during riding.

[0005] Poor environmental adaptability: poor low-temperature performance. In environments below -10℃, the internal medium fluidity decreases, leading to stretching / compression jamming, or even locking failure.

[0006] Redundant structural design: The cylinder is too large (the outer diameter of the cylinder is mostly above 22mm), which takes up the installation space of the bicycle frame. It also has a high compression ratio (the compression force value changes by more than 30% throughout the stroke), requiring a large external force to adjust, making the operation laborious. Summary of the Invention

[0007] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a high-speed extension controllable spring for adjusting a bicycle seat, comprising,

[0009] The cylinder comprises a starter rod, a hollow piston rod, a guide frame, a sealing ring, a pressurized air chamber, a positioning groove, a piston assembly, an oil chamber, and a cylinder. The cylinder is divided into a pressurized air chamber and an oil chamber by the positioning groove. The guide frame is located at one end of the cylinder, and a sealing ring is provided on one side of the guide frame. The piston assembly is located at one end of the oil chamber. One end of the hollow piston rod is connected to the piston assembly, and the other end extends through the guide frame to the outside of the cylinder. The starter rod is installed through the hollow piston rod. A piston valve needle is provided in the piston assembly and is connected to the starter rod.

[0010] As a preferred technical solution for a high-speed extension controllable spring for bicycle seat adjustment, the piston valve needle includes a shaft, a plug shaft, and a limiting end plate, wherein the size of the plug shaft is larger than the size of the shaft, and the size of the limiting end plate is larger than the size of the plug shaft.

[0011] As a preferred technical solution for a high-speed extension controllable spring for bicycle seat adjustment, the piston assembly further includes a piston body, in which a through groove and a first sealing groove are provided on the inner wall of the through groove, the shaft is disposed in the through groove, and a valve needle sealing ring is provided in the first sealing groove.

[0012] As a preferred technical solution for a high-speed extension controllable spring for bicycle seat adjustment, one end of the piston body is further provided with a connecting groove, the end of the hollow piston rod is fixed in the connecting groove, the inner wall of the connecting groove is provided with a second sealing groove, and a piston rod sealing ring is provided in the second sealing groove.

[0013] As a preferred technical solution for a high-speed extension controllable spring for bicycle seat adjustment, one end of the piston body is further provided with a sealing end, a third sealing groove is provided on the outer side of the sealing end, and a piston sealing ring is provided in the third sealing groove.

[0014] As a preferred technical solution for a high-speed extension controllable spring for bicycle seat adjustment, the inner wall of the through groove is further provided with a connecting groove, and the inner wall of the connecting groove is further provided with a fourth sealing groove, in which a locking sealing ring is provided, and the plug shaft and the connecting groove are dimensionally matched.

[0015] As a preferred technical solution for a high-speed extension controllable spring for bicycle seat adjustment, the other end of the through groove is also provided with an end groove, and a sink groove and a conical groove are provided between the end groove and the connecting groove, and the limiting end plate is provided in the sink groove and the conical groove.

[0016] As a preferred technical solution for a high-speed extension controllable spring for adjusting a bicycle seat, a high-speed oil passage hole is provided at the connection between the sealing end and the piston body, and the high-speed oil passage hole communicates with the connecting groove.

[0017] As a preferred technical solution for a high-speed extension controllable spring for bicycle seat adjustment, the high-speed oil passage is inclined at 25° and opened on the edge of the piston body.

[0018] As a preferred technical solution for a high-speed extension controllable spring for bicycle seat adjustment, the oil chamber is filled with hydraulic oil with a pour point ≤ -55℃.

[0019] The beneficial effects of this invention are: it solves the problem of slow extension speed and improves adjustment response efficiency; it reduces product size, optimizes installation adaptability, and reduces compression ratio to reduce changes in operating force; it enhances support rigidity, avoids seat swaying, and improves riding stability; it reduces the starting force of the push rod and improves operation convenience; it improves low-temperature performance, broadens the applicable temperature range, and ensures reliability in extreme environments. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0021] Figure 1 This is a schematic diagram of the overall cross-sectional structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the piston assembly in this invention;

[0023] Figure 3 This is a schematic diagram of the piston assembly's state structure during adjustment in this invention;

[0024] Figure 4 This is a schematic diagram of the piston assembly in the locked state in this invention.

[0025] Figure 5 This is a schematic diagram of the skeleton-guided installation state structure in this invention;

[0026] Figure 6 This is a schematic diagram of the piston assembly in its installed state according to the present invention;

[0027] Figure 7 Force value curve before durability testing;

[0028] Figure 8 This is a force value curve after the durability test.

[0029] Reference numerals: 1. Starting push rod; 2. Hollow piston rod; 3. Skeleton guide; 4. Sealing ring; 5. Pressurized air chamber; 6. Positioning groove; 7. Piston assembly; 71. Piston valve needle; 711. Shaft; 712. Plug shaft; 713. Limiting end plate; 72. Piston body; 722. First sealing groove; 723. Connecting groove; 724. Second sealing groove; 725. Sealing end; 726. Third sealing groove; 727. Connecting groove; 728. Fourth sealing groove; 729. End groove; 731. Conical groove; 73. Valve needle sealing ring; 74. Locking sealing ring; 75. Piston rod sealing ring; 721. Through groove; 76. High-speed oil passage hole; 77. Piston sealing ring; 8. Oil chamber; 9. Cylinder. Detailed Implementation

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0032] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0033] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0034] Example 1

[0035] Reference Figures 1-8This invention is used for height adjustment of bicycle seats. This embodiment provides a high-speed extension controllable spring for adjusting bicycle seats, including a starter rod 1, a hollow piston rod 2, a frame guide 3, a sealing ring 4, a pressurized air chamber 5, a positioning groove 6, a piston assembly 7, an oil chamber 8, and a cylinder 9. The cylinder 9 is divided into the pressurized air chamber 5 and the oil chamber 8 by the positioning groove 6. The frame guide 3 is located at one end of the cylinder 9, and a sealing ring 4 is provided on one side of the frame guide 3. The piston assembly 7 is located at one end of the oil chamber 8. One end of the hollow piston rod 2 is connected to the piston assembly 7, and the other end extends through the frame guide 3 to the outside of the cylinder 9. The starter rod 1 is installed through the hollow piston rod 2. A piston valve needle 71 is provided in the piston assembly 7 and is connected to the starter rod 1.

[0036] The cylinder 9 is an integral shell structure that houses the pressurized air chamber and oil chamber, providing rigid support. The hollow piston rod 2 is used to connect the seat and the piston assembly, transmitting support force and adjustment action. The skeleton guide 3 is installed at the top of the cylinder to axially guide the hollow piston rod and prevent it from shifting during extension and retraction. The sealing ring 4 is an annular structure that fits the inner wall of the cylinder and the skeleton guide 3 to achieve cylinder sealing and prevent medium leakage. The skeleton guide 3 is connected to and fixed to one end of the cylinder 9.

[0037] The starting push rod 1 passes through the hollow piston rod and is the control component that triggers the locking / unlocking action. The piston assembly 7 is the core functional component, which includes multiple sub-components to realize medium control and state switching. The pressurized air chamber 5 is the upper space inside the cylinder, which is filled with high-pressure nitrogen to provide extension power. The oil chamber 8 is the lower space inside the cylinder, which is filled with low-temperature hydraulic oil to achieve rigid locking. The positioning groove 6 is located at a specific position on the inner wall of the cylinder to limit the maximum extension stroke of the piston assembly and avoid excessive displacement.

[0038] The piston valve needle 71 includes a shaft 711, a plug shaft 712, and a limiting end plate 713. The size of the plug shaft 712 is larger than the size of the shaft 711, and the size of the limiting end plate 713 is larger than the size of the plug shaft 712.

[0039] A blocking shaft 712 is disposed at the end of the shaft 711, and a limiting end plate 713 is disposed at the end of the blocking shaft 712.

[0040] The piston valve needle 71 is a cylindrical rod-shaped structure. One end is in contact with the starting push rod, and the other end is adapted to lock the piston body 72. The piston body 72 is a disc-shaped structure with a high-speed oil passage hole, connecting the hollow piston rod and the piston valve needle. The valve needle sealing ring 73 is fitted in the middle of the piston valve needle to seal the gap between the valve needle and the piston body. The locking sealing ring 74 is embedded in the bottom of the piston body and works with the piston valve needle to open / close the oil passage hole. The piston rod sealing ring 75 is fitted at the connection between the hollow piston rod and the piston body to prevent the medium from leaking from the gap in the rod. The high-speed oil passage hole is a structure with a 25° inclination opened on the edge of the piston body. There are 6 holes in total, evenly distributed. The piston sealing ring 77 is fitted on the outside of the piston body, fitting against the inner wall of the cylinder, and isolating the oil chamber and the pressurized air chamber.

[0041] The piston assembly 7 also includes a piston body 72, in which a through groove 721 and a first sealing groove 722 are provided on the inner wall of the through groove 721. The shaft 711 is provided in the through groove 721, and a valve needle sealing ring 73 is provided in the first sealing groove 722.

[0042] The piston body 72 is also provided with a connecting groove 723 at one end, and the hollow piston rod 2 is fixed in the connecting groove 723 at the end. The inner wall of the connecting groove 723 is provided with a second sealing groove 724, and a piston rod sealing ring 75 is provided in the second sealing groove 724.

[0043] A groove structure is provided on the outer side of the hollow piston rod 2 at the location corresponding to the second sealing groove 724 for placing the piston rod sealing ring 75.

[0044] The piston body 72 is also provided with a sealing end 725 at one end, and a third sealing groove 726 is provided on the outside of the sealing end 725, and a piston sealing ring 77 is provided in the third sealing groove 726.

[0045] The sealing end 725 is larger than the piston body 72.

[0046] The inner wall of the through groove 721 is also provided with a connecting groove 727, and the inner wall of the connecting groove 727 is also provided with a fourth sealing groove 728. A locking sealing ring 74 is provided in the fourth sealing groove 728, and the plug shaft 712 and the connecting groove 727 are dimensionally matched.

[0047] The other end of the through groove 721 is also provided with an end groove 729. A sink groove and a conical groove 731 are provided between the end groove 729 and the connecting groove 727 for transition. The limiting end plate 713 is provided in the sink groove and the conical groove 731.

[0048] A high-speed oil passage hole 76 is provided at the connection between the sealing end 725 and the piston body 72, and the high-speed oil passage hole 76 communicates with the connecting groove 727.

[0049] The edge of the upper end face of the limiting end plate 713 contacts the inner wall of the conical groove 731.

[0050] The pressurized gas chamber 5 is filled with high-pressure nitrogen gas, which is the normal state under which the oil is in the oil chamber.

[0051] 1. External assembly: The skeleton guide 3 is fixed to the top of the cylinder 9 through the cylinder barrel constriction, and the sealing ring 4 is embedded in the cylinder barrel; the hollow piston rod 2 passes through the skeleton guide and the sealing ring, and the lower end is connected to the piston body 72 of the piston assembly 7 by press riveting;

[0052] 2. Internal connection: The starting push rod 1 coaxially passes into the hollow piston rod 2, and its lower end contacts the top of the piston valve needle 71; the piston valve needle 71 passes through the central hole of the piston body 72, and a valve needle sealing ring 73 is sleeved in the middle; the locking sealing ring 74 is snapped into the annular groove at the bottom of the piston body 72 and seals against the lower end of the piston valve needle 71; the piston rod sealing ring 75 is sleeved on the connection end between the hollow piston rod 2 and the piston body 72; the piston sealing ring 77 is sleeved on the annular groove on the outside of the piston body 72 and slides to seal against the inner wall of the cylinder 9.

[0053] 3. Medium chamber: The piston assembly 7 divides the inside of the cylinder 9 into upper and lower chambers - the upper chamber is the pressurized air chamber 5 (filled with 6MPa high-pressure nitrogen), and the lower chamber is the oil chamber 8 filled with special low-temperature hydraulic oil, with the filling amount being 100% of the oil chamber volume; the positioning groove 6 is an annular protrusion on the inner wall of the cylinder 9, located above the pressurized air chamber 5, which restricts the maximum extension position of the piston assembly 7.

[0054] The working principle of this invention is explained below in terms of "locked state" and "adjustment state";

[0055] 1. Locked state, i.e., during normal riding.

[0056] Structural state: When no external force is applied to the starting push rod 1, the nitrogen pressure in the pressurized air chamber 5 squeezes the oil and pushes the piston valve needle 71 to reset upward. The lower end of the piston valve needle presses against the locking seal ring 74, sealing the high-speed oil passage hole 76 on the piston body 72.

[0057] Medium status: The hydraulic oil in the oil chamber 8 cannot flow due to the high-speed oil passage being closed, and the liquid is incompressible, so the piston assembly 7 cannot move up and down, and the hollow piston rod 2 remains fixed, thus achieving seat height locking.

[0058] Performance assurance: Piston seal ring 77 isolates the pressurized air chamber and oil chamber to prevent nitrogen from mixing into the oil; each seal ring ensures no leakage of the medium and maintains the pressure of the pressurized air chamber and the sealing of the oil chamber.

[0059] 2. Adjustment status, i.e., when adjusting the seat height.

[0060] Unlocking action: Apply downward pressure to the starter rod 1, the rod pushes the piston valve needle 71 to move downward, the lower end of the piston valve needle disengages from the locking seal ring 74, and the high-speed oil passage 76 opens;

[0061] Stretching process: Refer to Figure 3 Nitrogen gas expands in pressurized air chamber 5, pushing piston assembly 7 to move upward. Hydraulic oil in pressurized air chamber flows rapidly into one side of oil chamber 8 through high-speed oil passage 76 at an angle of 25°. Hollow piston rod 2 extends upward synchronously with piston assembly, achieving a seat lifting and extension speed of 1.6m / s.

[0062] Compression process: Press the seat down, the hollow piston rod 2 drives the piston assembly 7 to move downward, the volume of the oil chamber 8 below the piston assembly 7 decreases, the hydraulic oil flows into the pressurized air chamber through the high-speed oil passage 76, the nitrogen is compressed, and the seat is lowered.

[0063] Relocking: Remove the pressure from the starting push rod 1, and the nitrogen pressure pushes the piston valve needle 71 to reset, pressing the locking seal ring 74 again to close the high-speed oil passage and restore the locked state.

[0064] In summary, through structural design, this invention enables the hollow piston rod 2 to be unlocked by pressing the start rod 1. At this time, pressing the hollow piston rod 2 and the seat can adjust the seat downwards. If the seat is in a low position, pressing the start rod 1 will push the oil back into the oil chamber, realizing the automatic upward adjustment of the seat.

[0065] Furthermore, as an extended application, a bracket is attached to the end of the hollow piston rod 2, on which a seat is mounted. A push rod motor can be installed on the bracket, and the push rod motor is located at the top of the starting rod 1. The push rod of the push rod motor is coaxial with the starting rod 1. The push rod motor is led out through a button switch. Specifically, pressing the button activates the push rod motor, pushing the starting rod 1 downward. At this time, the entire seat can be adjusted. When the button is released, the push rod motor is de-energized, and the starting rod 1 is pushed back up to reset by the push rod motor push rod under the pressure of high-pressure nitrogen.

[0066] The model of the push rod motor and the power supply are selected according to the specific vehicle model. The push rod motor's thrust and the power supply's energy storage capacity need to be considered.

[0067] Furthermore, the duration of button press can be correlated with the extension of push rod through circuit design, thereby controlling the downward movement of starter rod 1 and adjusting the opening of piston valve needle 71. The specific circuit structure can be based on existing designs and will not be elaborated further.

[0068] The technical effects of this invention are reflected in the following aspects:

[0069] 1. Compact size and highly adaptable, specifically reflected in structural improvements.

[0070] Structural design: The outer diameter of cylinder 9 is optimized to 18mm (most existing products are 22-25mm), reducing the radial dimension; the hollow piston rod 2 adopts a thin-wall design (wall thickness 1.2mm), reducing weight while ensuring strength; Functional advantages: Saves bicycle frame installation space, is compatible with smaller models such as folding bikes, and reduces overall weight by 15% without increasing the overall load of the bike.

[0071] 2. Low compression ratio and stable operating force, specifically reflected in structural improvements.

[0072] Structural design: Increase the volume of the pressurized air chamber 5 and reduce the outer diameter of the hollow piston rod 2 (6mm) to reduce the piston rod's occupation of the air chamber volume; Functional advantages: The compression force value change rate is 1.55% throughout the entire stroke (0~150mm) (existing products exceed 1.9%), making the external force applied when adjusting the seat more stable and avoiding the problem of "weakness in the initial pressing and difficulty in the later pressing".

[0073] 3. High-speed response and high adjustment efficiency, specifically reflected in structural improvements and media optimization.

[0074] Structural Design: The high-speed oil passage 76 adopts a 25° inclined design (most existing products use vertical holes), and the hole diameter is enlarged to 2mm, while the number of oil passages is increased to 6; Media Optimization: Low-viscosity, low-temperature hydraulic oil is selected (kinematic viscosity at 20℃ is 12mm). 2 / s), reducing flow resistance; Functional advantages: Extension speed up to 1.6m / s, 60% higher than existing products (0.6-1.0m / s), seat height adjustment takes only 0.1 seconds (when the stroke is 150mm), with rapid response; The inclined hole design reduces oil flow noise, and the noise during operation is <50dB.

[0075] 4. Strong locking rigidity and high security.

[0076] Structural design: The locking seal ring 74 is made of fluororubber (oil-resistant and high-pressure resistant) to enhance sealing pressure; the piston seal ring 77 adopts a two-way sealing structure to prevent oil and nitrogen from crossing the cavity;

[0077] Functional advantages: When 2000N of pressure (equivalent to 150kg body weight) is applied in the locked state, the piston rod displacement is less than 3mm within 1 minute, which is far lower than existing products (<5mm). The seat does not shake when riding, and the safety on bumpy roads is improved.

[0078] 5. Wide adaptability to low temperatures and high environmental reliability

[0079] Medium optimization: The oil chamber 8 is filled with special low-temperature hydraulic oil with a pour point of ≤-55℃, which still maintains good fluidity in an environment of -40℃; the high-pressure nitrogen has a purity of 99.9%, which avoids impurities from precipitating and clogging the oil passage at low temperatures; Functional advantages: The working temperature range covers -40~80℃ (most existing products are -20~60℃), and it can be used normally in extreme environments such as northern winters and southern summers without jamming or locking failure.

[0080] 6. Low starting force and easy operation

[0081] Structural Design: The piston valve needle 71 diameter is reduced to 2.5mm (most existing products are 4mm), reducing the thrust required for piston valve needle movement; the locking seal ring 74 is made of a low-friction coefficient material (friction coefficient <0.1); Functional Advantages: The starting force of the starting rod 1 is ≤30N (most existing products are 50-80N), which can be easily pressed with one hand, making it easy for female or teenage cyclists to operate, and it is also suitable for electronic control adjustment devices with insufficient power due to size limitations.

[0082] Furthermore, in a durability test of a certain product, the gas spring piston rod was clamped downwards on a testing machine equipped with an oil collection device, and a cycle life test was conducted for 40,000 cycles at a frequency of 6 to 12 cycles / min. The temperature of the gas spring cylinder should not exceed 50℃ throughout the entire test. (For stroke ≤ 50mm, the actual stroke was used; for stroke > 50mm, a 50mm stroke was used.) The comparison before and after the test is shown in Tables 1 and 2 below.

[0083] Table 1 Force values ​​before the test

[0084]

[0085] Table 2 Force values ​​after the test

[0086]

[0087] Correspondingly, Figure 7 This is a force curve before the experiment. Figure 8 The force curve after the test shows that the decrease in nominal force Fa is 7.38%, the locking force meets the requirements after the test, and the amount of oil carried out is 0.21g.

[0088] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0089] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high-speed extension controllable spring for adjusting a bicycle seat, characterized in that: include, The cylinder (9) consists of a starting push rod (1), a hollow piston rod (2), a skeleton guide (3), a sealing ring (4), a pressurized air chamber (5), a positioning groove (6), a piston assembly (7), an oil chamber (8), and a cylinder (9). The cylinder (9) is divided into a pressurized air chamber (5) and an oil chamber (8) by the positioning groove (6). The skeleton guide (3) is located at one end of the cylinder (9), and a sealing ring (4) is located on one side of the skeleton guide (3). The piston assembly (7) is located at one end of the oil chamber (8). One end of the hollow piston rod (2) is connected to the piston assembly (7), and the other end extends through the skeleton guide (3) to the outside of the cylinder (9). The starting push rod (1) is installed through the hollow piston rod (2). A piston valve needle (71) is installed in the piston assembly (7), and the piston valve needle (71) is connected to the starting push rod (1). The piston valve needle (71) includes a shaft (711), a plug shaft (712), and a limiting end plate (713). The size of the plug shaft (712) is larger than the size of the shaft (711), and the size of the limiting end plate (713) is larger than the size of the plug shaft (712). The inner wall of the through groove (721) is provided with a connecting groove (727), and the inner wall of the connecting groove (727) is also provided with a fourth sealing groove (728). A locking sealing ring (74) is provided in the fourth sealing groove (728), and the plug shaft (712) and the connecting groove (727) are dimensionally matched. The piston valve needle (71) has a rod diameter of 2.5 mm; the cylinder (9) has an outer diameter of 18 mm; the hollow piston rod (2) has an outer diameter of 6 mm; and the hollow piston rod (2) has a wall thickness of 1.2 mm. The locking seal (74) is made of fluororubber. The piston assembly (7) further includes a piston body (72), in which a through groove (721) and a first sealing groove (722) are provided on the inner wall of the through groove (721), the shaft (711) is provided in the through groove (721), and a valve needle sealing ring (73) is provided in the first sealing groove (722). The end of the through groove (721) is provided with an end groove (729), and a sink groove and a conical groove (731) are provided between the end groove (729) and the connecting groove (727) for transition. The limiting end plate (713) is provided in the sink groove and the conical groove (731). The edge of the upper end face of the limiting end plate (713) contacts the inner wall of the conical groove (731); The high-speed oil passage (76) is set at an angle of 25° and opened on the edge of the piston body; The high-speed oil passage (76) has a diameter of 2mm and a quantity of 6, and uses low-viscosity low-temperature hydraulic oil.

2. The high-speed extension controllable spring for adjusting a bicycle seat according to claim 1, characterized in that: The piston body (72) has a connecting groove (723) at one end, and the hollow piston rod (2) is fixed in the connecting groove (723). The inner wall of the connecting groove (723) has a second sealing groove (724), and a piston rod sealing ring (75) is provided in the second sealing groove (724).

3. The high-speed extension controllable spring for adjusting a bicycle seat according to claim 2, characterized in that: The piston body (72) is also provided with a sealing end (725) at one end, and a third sealing groove (726) is provided on the outside of the sealing end (725), and a piston sealing ring (77) is provided in the third sealing groove (726).

4. The high-speed extension controllable spring for adjusting a bicycle seat according to claim 3, characterized in that: A high-speed oil passage hole (76) is provided at the connection between the sealing end (725) and the piston body (72), and the high-speed oil passage hole (76) communicates with the connecting groove (727).

5. The high-speed extension controllable spring for adjusting a bicycle seat according to claim 4, characterized in that: The oil chamber (8) is filled with hydraulic oil with a pour point ≤ -55℃.

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