Electric lifting device for office chair

Abstract

The application discloses an electric lifting device for an office chair and belongs to the technical field of office furniture. The electric lifting device comprises a seat body, a base, a first pipe connected with the seat body and a second pipe connected with the base. The electric lifting device further comprises a first piston which divides an inner part of the first pipe into an upper liquid cavity and a lower rod cavity, and a bottom of the first piston is provided with a piston rod. The electric lifting device further comprises an energy storage device which is internally provided with a storage cavity. The electric lifting device further comprises a second piston which is slidably arranged in the storage cavity of the energy storage device and divides the storage cavity into a liquid storage cavity and a gas storage cavity. The electric lifting device further comprises a flow channel, the liquid storage cavity and the upper liquid cavity of the first pipe are connected in communication through the flow channel, and a liquid valve is connected in series on the flow channel. The liquid valve is accurately adjusted by electric control, stable pressure compensation is realized in combination with the energy storage device, multiple sealing structures and a guide device are adopted to ensure operation stability, and the electric lifting device has the advantages of convenient operation, stable lifting, reliable sealing and energy storage function.

Description

Technical Field

[0001] This utility model belongs to the field of office furniture technology, and specifically relates to an electric lifting device for office chairs. Background Technology

[0002] Currently, the height adjustment mechanisms for office chairs suffer from the following technical defects: traditional hydraulic adjustment mechanisms require manual operation of a lever, which is not only inconvenient but also lacks precise height control; while pneumatic adjustment mechanisms are relatively labor-saving, they suffer from unstable air pressure leading to uneven height adjustment. In existing technologies, manual adjustment mechanisms require users to interrupt their work and stand up, which is particularly inconvenient in modern intelligent office environments. Furthermore, conventional height adjustment devices lack effective guiding structures and sealing designs, making them prone to wobbling and leakage. More importantly, existing devices cannot organically combine electric control with energy storage functions, failing to meet users' demands for intelligent and automated office environments. These technical defects severely impact the user experience and work efficiency of office chairs. Therefore, existing technologies urgently need improvement to address these issues. Utility Model Content

[0003] The purpose of this application is to provide an electric lifting device for office chairs, which has the advantages of convenient operation, smooth lifting, reliable sealing and energy storage function.

[0004] This application provides an electric lifting device for an office chair, comprising: a seat body, a base, a first tube connecting the seat body, and a second tube connecting the base; the first tube is axially and vertically fitted into the second tube, and the inner cavity of the second tube guides the first tube; it also includes a first piston slidably disposed inside the first tube, the first piston dividing the interior of the first tube into an upper liquid chamber and a lower rod chamber, the bottom of the first piston having a piston rod, the bottom of the piston rod being fixed to the bottom of the second tube; it also includes an energy storage device having a storage chamber inside; it also includes a second piston slidably disposed within the storage chamber of the energy storage device, the second piston dividing the storage chamber into a liquid storage chamber and a gas storage chamber; it also includes a flow channel, the liquid storage chamber being connected to the upper liquid chamber of the first tube through the flow channel; and it also includes a liquid valve, the liquid valve being connected in series on the flow channel, used to open or close the flow channel to control the flow of liquid between the liquid storage chamber and the upper liquid chamber.

[0005] Furthermore, the aforementioned liquid valve is a normally closed solenoid valve.

[0006] Furthermore, the aforementioned liquid valve is installed between the energy storage device and the flow channel.

[0007] Furthermore, a first sealing ring is provided between the outer periphery of the first piston and the inner wall of the first tube.

[0008] Furthermore, a second sealing ring is provided between the outer periphery of the second piston and the inner wall of the storage cavity.

[0009] Furthermore, flanges are provided at the outlet of the liquid storage chamber, the inlet and outlet of the liquid valve, both ends of the flow channel, and the inlet of the upper liquid chamber of the first pipe of the above-mentioned energy storage device. Each component is fixedly connected by the cooperation of flanges and bolts.

[0010] Furthermore, it also includes a limiting structure to prevent relative rotation between the first tube and the second tube. The limiting structure includes a long key on the outer wall of the first tube and a keyway on the inner wall of the second tube, with the long key and the keyway cooperating.

[0011] Furthermore, the bottom of the first tube is provided with a sealing cap, which is axially sleeved on the outside of the piston rod to prevent the first piston from coming out of the first tube.

[0012] Furthermore, the lower rod cavity is filled with lubricating oil, which adheres between the outer peripheral wall of the first piston and the inner wall of the first tube.

[0013] Furthermore, the aforementioned energy storage device is pre-installed with an inflation port that connects to the gas storage chamber.

[0014] As can be seen from the above, the electric lifting device for office chairs provided in this application precisely adjusts the hydraulic system through an electrically controlled hydraulic valve, achieves stable pressure compensation in combination with an energy storage device, and ensures operational stability by adopting a multi-seal structure and a guiding device. It has the advantages of convenient operation, smooth lifting, reliable sealing and energy storage function. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an electric lifting device provided in an embodiment of this application.

[0016] Figure 2 for Figure 1 Sectional view of AA.

[0017] Figure 3 A cross-sectional view of an energy storage device provided in an embodiment of this application.

[0018] Labeling Explanation: 10, Seat Body; 20, Base; 30, First Pipe; 31, Upper Liquid Chamber; 32, Lower Rod Chamber; 33, First Piston; 331, First Sealing Ring; 34, Piston Rod; 35, Long Key; 36, Sealing Cap; 40, Second Pipe; 41, Keyway; 50, Flow Channel; 60, Liquid Valve; 70, Energy Storage Device; 71, Second Piston; 711, Second Sealing Ring; 72, Liquid Storage Chamber; 73, Air Storage Chamber; 74, Inflation Interface; 80, Flange. Detailed Implementation

[0019] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0020] The following disclosure provides many different embodiments or examples for implementing various structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or reference letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0021] In existing technologies, office chair height adjustment mechanisms generally employ hydraulic or pneumatic principles, with seat height adjustment controlled by a manual lever. Users need to bend over or stand up to operate the adjustment device. In intelligent office scenarios, traditional manual adjustment methods are inconvenient and inefficient, failing to meet the demands of automated control. Current technologies lack electrically controlled and compact lifting mechanisms, leaving the seat height adjustment process reliant on manual intervention.

[0022] To address the aforementioned issues, those skilled in the art have found that manual operation suffers from drawbacks such as large amplitude of movement and slow response speed. After research and analysis, a method combining a hydraulic drive system with electric control components is proposed, transmitting power through a closed hydraulic circuit. Considering the incompressible nature of liquids, an energy storage device 70 is designed to balance system pressure fluctuations. To solve the problem of the large size of traditional hydraulic systems, a double-pipe sleeve structure is adopted to guide axial movement, while the piston assembly is integrated inside the pipe body to reduce the overall size. Electromagnetic control of the fluid flow direction is achieved by using a solenoid valve to control the electric operation of seat lifting.

[0023] Therefore, as Figures 1 to 3 As shown, this application proposes a system including a seat body 10, a base 20, a first tube 30 connecting the seat body 10, and a second tube 40 connecting the base 20. The first tube 30 is axially and vertically fitted inside the second tube 40, and the inner cavity of the second tube 40 guides the first tube 30. A first piston 33, slidably disposed inside the first tube 30, divides the interior of the first tube 30 into an upper liquid chamber 31 and a lower rod chamber 32. A piston rod 34, fixed to the bottom of the second tube 40, is provided at the bottom of the first piston 33. The energy storage device 70 has a storage chamber divided into a liquid storage chamber 72 and a gas storage chamber 73 by a second piston 71. The liquid storage chamber 72 and the upper liquid chamber 31 are connected by a flow channel 50 with a liquid valve 60 to control the flow of liquid between the chambers.

[0024] Among them, liquid valve 60 refers to the opening and closing device used to control the flow of liquid in the flow channel 50.

[0025] Among them, the energy storage device 70 refers to a sealed container with a storage cavity, which can be a metal shell, and its interior is divided into a liquid storage cavity 72 and a gas storage cavity 73 by a second piston 71.

[0026] Among them, the flow channel 50 refers to the liquid transmission channel connecting the liquid storage chamber 72 and the upper liquid chamber 31, which can be made of metal pipe.

[0027] The nested structure of the first tube 30 and the second tube 40 refers to the nested combination of two tubes with different diameters. In this embodiment, the first tube 30 with a smaller outer diameter can be inserted into the second tube 40 with a larger inner diameter, and axial sliding guidance is achieved through the contact surface of the tube walls. The gas storage chamber 73 of the energy storage device 70 is filled with compressed gas, such as nitrogen, and pressure compensation is provided through the elasticity of gas compression. The opening and closing control of the liquid valve 60 can adopt an electromagnetically driven valve core structure, for example, by generating magnetic force through energizing a coil to push the valve core displacement and change the on / off state of the flow channel 50.

[0028] Specifically, when the liquid valve 60 is open and the seat is in use, under the influence of weight, the first pipe 30 moves downward along the second pipe 40, reducing the volume of the upper liquid chamber 31 of the first pipe 30. The liquid in the upper liquid chamber 31 enters the liquid storage chamber 72 of the energy storage device 70 through the flow channel 50. The liquid in the liquid storage chamber 72 pushes the second piston 71, which compresses the gas in the gas storage chamber 73, thus lowering the seat body 10. When the liquid valve 60 is open and the seat is not in use, the compressed gas in the gas storage chamber 73 of the energy storage device 70 pushes the second piston 71. The second piston 71 pushes the liquid in the liquid storage chamber 72 into the upper liquid chamber 31 of the first pipe 30 through the flow channel 50. The liquid in the upper liquid chamber 31 causes the first pipe 30 to move upward along the second pipe 40, thus raising the seat body 10. The piston rod 34 is fixed to the bottom of the second tube 40, providing reverse support force for the first piston 33. The bottom end of the piston rod 34 is threaded, and the bottom of the second tube 40 has a countersunk nut seat for threaded connection of the piston rod 34, thus achieving a fixed connection between the piston rod 34 and the second tube 40. When the hydraulic valve 60 is closed, the liquid flow path is blocked, and the hydraulic system forms a closed loop to maintain the current height. The gas storage chamber 73 of the energy storage device 70 absorbs system pressure fluctuations through gas compression, preventing sudden changes in liquid pressure from affecting the smoothness of movement. The sleeved connection between the first tube 30 and the second tube 40 restricts the direction of movement, preventing radial deviation during lifting and lowering.

[0029] Compared to existing technologies, traditional manual adjustment mechanisms require mechanical linkages to transmit operating force. This solution uses an electromagnetic valve to control fluid flow via electrical signals, achieving contactless electric adjustment. Existing hydraulic lifting devices mostly employ external cylinder structures; this solution integrates the piston assembly inside the tube, reducing the axial dimension of the device. Conventional pressure compensation devices use spring structures; this solution utilizes the gas compression characteristics of the energy storage device 70 to provide more stable pressure buffering.

[0030] Through the above technical solution, this application achieves electric control of seat height, allowing users to adjust the height without manual operation. The dual-tube socket structure integrates guiding and driving functions within a limited space, and the energy storage device 70 effectively balances system pressure fluctuations, ensuring a smooth and stable lifting process. The solenoid valve control method has a fast response speed and can be adapted to intelligent control systems to achieve automated height adjustment.

[0031] This application further proposes that the liquid valve 60 is a normally closed solenoid valve.

[0032] Among them, the normally closed solenoid valve refers to an electromagnetically controlled valve whose valve body is in the closed state when power is off. Specifically, it can be implemented using a coil-driven valve core structure, where the flow channel 50 is opened or closed by controlling the displacement of the valve core through electromagnetic force. Compared with existing technologies, traditional manual regulating valves rely on mechanical lever operation, which has the risks of response delay and sealing failure. In contrast, the normally closed solenoid valve achieves rapid response through electrical control signals, and its sealing structure automatically locks the flow channel 50 when power is off, effectively preventing pressure loss caused by liquid leakage.

[0033] Through the above technical solution, this application achieves precise electrical control of the liquid on / off state, eliminates the defects of inconvenient operation and low sealing reliability of traditional manual valves, ensures that the lifting device maintains stable hydraulic system pressure when not in operation, and provides a fast-response execution unit for electric control.

[0034] This application further proposes that a liquid valve 60 be installed between the energy storage device 70 and the flow channel 50.

[0035] Specifically, the liquid valve 60 is directly installed between the outlet of the liquid storage chamber 72 and the inlet of the flow channel 50 in the energy storage device 70. Because the liquid valve 60 is installed close to the energy storage device 70, its opening and closing action can directly act on the outlet of the liquid storage chamber 72, avoiding response delay caused by the inertia of the liquid within the flow channel 50. This solution simplifies the piping layout by integrating the liquid valve 60 at the connection node between the energy storage device 70 and the flow channel 50. Simultaneously, it allows for maintenance of the liquid valve 60 to be performed directly on the surface of the energy storage device 70 without disassembling the flow channel 50 or the first pipe 30.

[0036] Through the above technical solution, this application achieves precise control of liquid flow by the opening and closing action of the hydraulic valve 60, solves the problem of response lag caused by the dispersed valve positions in traditional hydraulic mechanisms, and reduces the complexity of equipment maintenance through a compact layout, ensuring that the lifting device maintains stable sealing performance during long-term use.

[0037] This application further proposes that a first sealing ring 331 is provided between the outer periphery of the first piston 33 and the inner wall of the first tube 30.

[0038] The axial sliding sealing structure of the first piston 33 can be a piston body with an annular groove. The first sealing ring 331 is an annular sealing element surrounding the outer edge of the first piston 33, which can be made of rubber material, installed in the groove of the first piston 33, and fills the gap between the piston and the pipe wall through elastic deformation. The first sealing ring 331 is used to prevent liquid in the upper liquid chamber 31 from leaking into the lower rod chamber 32, ensuring stable pressure in the hydraulic system.

[0039] Specifically, the first piston 33 slides axially to change the volume of the upper liquid chamber 31, thereby driving the first tube 30 to rise and fall. The first sealing ring 331 is fitted between the contact surface between the outer periphery of the piston and the inner wall of the first tube 30, maintaining a continuous seal during piston movement. When the liquid valve 60 is opened, the first sealing ring 331 prevents liquid from leaking along the edge of the first piston 33 into the lower rod chamber 32, thus ensuring effective transmission of hydraulic pressure.

[0040] Through the above technical solution, this application can effectively maintain the pressure isolation between the upper liquid chamber 31 and the lower rod chamber 32, avoid lifting failure caused by liquid leakage, and at the same time reduce the friction loss when the first piston 33 moves, and extend the service life of the device.

[0041] This application further proposes to provide a second sealing ring 711 between the outer periphery of the second piston 71 and the inner wall of the storage cavity.

[0042] The second piston 71 refers to the sliding component inside the energy storage device 70 used to separate the liquid storage chamber 72 and the gas storage chamber 73. Specifically, it can be implemented by a metal piston with an annular groove, which is used to fix the second sealing ring 711.

[0043] The second sealing ring 711 refers to the annular sealing element installed between the outer periphery of the second piston 71 and the inner wall of the storage cavity. Specifically, it can be made of elastic material such as nitrile rubber or fluororubber, and fills the assembly gap between the piston and the cavity wall through elastic deformation.

[0044] Specifically, the second sealing ring 711 is fitted into an annular groove on the outer periphery of the second piston 71, with its outer diameter slightly larger than the inner diameter of the storage cavity. When the second piston 71 slides within the storage cavity, the second sealing ring 711 is compressed, causing radial deformation and forming a tight contact with the cavity wall. This contact pressure prevents the liquid in the liquid storage cavity 72 from entering the gas storage cavity 73 through the gap between the second piston 71 and the cavity wall, while simultaneously preventing the compressed gas in the gas storage cavity 73 from permeating back into the liquid storage cavity 72. The elastic properties of the second sealing ring 711 ensure that it maintains an effective seal throughout the reciprocating motion of the second piston 71, preventing the gap from widening due to long-term wear.

[0045] Through the above technical solution, this application effectively blocks fluid leakage between the liquid storage chamber 72 and the gas storage chamber 73 inside the energy storage device 70, maintains the working pressure stability of the hydraulic system, reduces the phenomenon of lifting device jamming or height retraction caused by seal failure, and extends the service life of the device.

[0046] This application further proposes that flanges 80 are provided at the outlet of the liquid storage chamber 72 of the energy storage device 70, the inlet and outlet of the liquid valve 60, both ends of the flow channel 50, and the inlet of the upper liquid chamber 31 of the first pipe 30. Each component is fixedly connected by the cooperation of flanges 80 and bolts.

[0047] Flange 80 refers to a disc-shaped connector with an annular sealing surface. Specifically, it can be made of metal and machined into a disc structure with bolt holes, achieving fluid channel sealing through end-face contact. Bolts are threaded fasteners, specifically standard hexagonal head bolts, which apply axial preload to ensure a tight fit between the flange 80 end faces. The fit between the flange 80 and the bolts forms a rigid connection interface, evenly distributing the locking force and preventing seal failure due to localized deformation.

[0048] Specifically, flange 80 connections are used between the outlet of the liquid storage chamber 72 and the inlet of the liquid valve 60, between the outlet of the liquid valve 60 and the inlet of the flow channel 50, and between the outlet of the flow channel 50 and the inlet of the upper liquid chamber 31. During installation, the flange 80 disc face is fitted with a sealing gasket, and torque is applied after the bolts pass through the flange 80 holes to generate sufficient contact pressure on the sealing surface. During liquid transmission, the sealing gasket at the flange 80 connection is compressed and deformed to fill the microscopic gaps, preventing liquid leakage. When maintenance is required, the corresponding components can be disassembled by loosening the bolts without damaging the pipeline structure.

[0049] Compared to existing technologies, traditional hydraulic systems often use welding or adhesive bonding to connect pipelines, which results in difficulties in disassembly and irreparable sealing surfaces. The flange 80 connection, however, utilizes a detachable mechanical fastening structure, ensuring reliable sealing under high pressure and enabling modular assembly, significantly reducing maintenance complexity.

[0050] Through the above technical solution, this application solves the leakage risk caused by loose connections in liquid flow components, while simplifying the assembly and maintenance process. The standardized interface design of the 80 flange connection allows for independent replacement of each component, avoiding the problem of overall scrapping due to local damage. The elastic compensation characteristics of the sealing gasket can adapt to system pressure fluctuations, ensuring sealing stability during long-term use.

[0051] This application further proposes a limiting structure to prevent relative rotation between the first tube 30 and the second tube 40, including a long key 35 provided on the outer wall of the first tube 30 and a keyway 41 provided on the inner wall of the second tube 40, wherein the long key 35 and the keyway 41 cooperate.

[0052] The long key 35 refers to a strip-shaped protrusion extending axially along the outer wall of the first tube 30. It can be fixed to the outer surface of the tube body by welding or integral molding, and its cross-sectional shape can be rectangular or trapezoidal. This structure forms an axial sliding constraint through cooperation with the keyway 41, preventing circumferential displacement of the two tubes during lifting and lowering.

[0053] The keyway 41 refers to a groove structure extending axially along the inner wall of the second tube 40. It can be formed by machining or casting, and its depth is slightly greater than the height of the long key 35 to retain sliding clearance. This groove and the long key 35 form a complementary fit, allowing axial displacement while restricting rotational freedom.

[0054] Specifically, during the operation of the electric lifting device, when the first tube 30 moves axially along the second tube 40, the long key 35 always slides within the keyway 41. This mechanical limiting method forms a guiding constraint through the structural features of the tube itself, preventing the two tubes from rotating relative to each other when bearing the load of the seat. Since the keyway 41 has only a single guide channel along the entire circumference of the inner wall of the tube, the fitting accuracy between the long key 35 and the keyway 41 can be ensured by using standardized molds during tube processing.

[0055] Through the above technical solution, this application achieves linear motion without rotational deviation during the lifting and lowering of the first tube 30, avoiding wear of the sealing structure caused by tube torsion. This limiting method simplifies the assembly process while ensuring guiding accuracy, and its integrated structural design enhances the overall strength of the tube, making it suitable for long-term, high-frequency lifting and lowering operations of office chairs.

[0056] This application further proposes that the lower rod cavity 32 is filled with lubricating oil, which adheres between the outer peripheral wall of the first piston 33 and the inner wall of the first tube 30. The lubricating oil can be mineral oil or synthetic oil with a viscosity index of 80-120, forming an oil film layer by wetting the contact surface between the piston and the tube wall, thereby reducing the coefficient of sliding friction.

[0057] Specifically, lubricating oil is filled in the lower rod cavity 32 space between the bottom of the first piston 33 and the sealing cap 36. When the first tube 30 moves up and down relative to the second tube 40, the first piston 33 slides axially. The lubricating oil forms a continuous lubricating film in the gap between the outer circumference of the first piston 33 and the tube wall of the first tube 30, covering the metal contact surface and isolating direct friction. The lubricating film buffers the impact of piston movement through viscous resistance, while carrying away the heat generated by friction.

[0058] Through the above technical solution, this application achieves continuous lubrication protection of the contact surface between the piston and the pipe wall, effectively reducing mechanical wear and extending the service life of the lifting device. The viscous damping formed by the lubricating oil further suppresses vibration during the lifting process, ensuring smooth and reliable seat height adjustment.

[0059] This application further proposes that the bottom of the first tube 30 is provided with a sealing cap 36, which is axially sleeved on the piston rod 34 to prevent the first piston 33 from coming out of the first tube 30.

[0060] The sealing cap 36 refers to the sealing component that covers the bottom opening of the first tube 30. It can be made of metal stamping or injection molding, and its inner diameter is slightly larger than the outer diameter of the piston rod 34 to form a clearance fit. "Sleeveted onto the piston rod 34" means that the inner hole of the sealing cap 36 extends axially along the piston rod 34 to form a guide sleeve structure. The length of this sleeve can be 0.5 times the diameter of the piston rod 34. "Axial sleeve" means that the sealing cap 36 and the piston rod 34 are only allowed to move relative to each other along the axial direction.

[0061] Specifically, the sealing cap 36 is bolted to the bottom end of the first tube 30, and its sleeve extends to the outer periphery of the piston rod 34. When the first tube 30 moves up and down relative to the second tube 40, the sleeve of the sealing cap 36 slides along the surface of the piston rod 34, forming an axial movement guide. When the first piston 33 descends to its limit position, the end face of the sealing cap 36 contacts the bottom of the first piston 33, forming a mechanical limit and preventing the first piston 33 from continuing to move downward and disengaging from the first tube 30. An annular sealing gasket is provided between the sealing cap 36 and the first tube 30 to prevent lubricating oil leakage from the lower rod cavity 32.

[0062] Through the above technical solution, the sealing cap 36 structure added to the piston rod 34 in this application can effectively limit the axial displacement range of the first piston 33, avoid piston disengagement accidents under extreme operating conditions, and improve the safety and reliability of the device operation. This structure also forms a lubricating oil sealing interface, reducing the risk of lubricating medium leakage and extending the service life of the device.

[0063] This application further proposes that the energy storage device 70 is pre-installed with an air filling interface 74 that connects to the air storage chamber 73.

[0064] The energy storage device 70 refers to a sealed container with dual functions of storing liquid and gas. Specifically, it can be implemented as a chambered pressure vessel, in which the storage chamber is divided into a liquid storage chamber 72 and a gas storage chamber 73 by a second piston 71. The gas filling interface 74 refers to a standardized gas connection component for connecting to an external gas source. Specifically, it can be implemented as a quick connector with a one-way valve, which is pre-installed on the outer wall of the gas storage chamber 73 of the energy storage device 70.

[0065] Specifically, the gas storage chamber 73 is detachably connected to an external gas source via the inflation port 74. When the internal gas pressure of the gas storage chamber 73 is depleted due to long-term use, compressed gas can be directly replenished through the inflation port 74 without disassembling the energy storage device 70. During inflation, the second piston 71 moves towards the liquid storage chamber 72 under the action of gas pressure, compressing the volume of the liquid storage chamber 72. Liquid enters the upper liquid chamber 31 through the flow channel 50. At this time, the liquid valve 60 is in the closed state to maintain system pressure balance. The preset position of the inflation port 74 is sealed to prevent gas leakage from affecting the stability of the device.

[0066] Through the above technical solution, this application realizes the controllability and convenience of 70-gas pressure compensation for energy storage devices, solves the problem of lifting height deviation caused by gas pressure attenuation in traditional devices, and reduces equipment maintenance costs and extends the service life of lifting devices.

[0067] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An electric lifting device for an office chair, characterized in that, include: Seat body (10), base (20), first tube (30) connecting the seat body (10) and second tube (40) connecting the base (20); The first tube (30) is axially and vertically sleeved inside the second tube (40), and the inner cavity of the second tube (40) guides the first tube (30); It also includes a first piston (33) that is slidably disposed inside the first tube (30). The first piston (33) divides the inside of the first tube (30) into an upper liquid chamber (31) and a lower rod chamber (32). The bottom of the first piston (33) is provided with a piston rod (34), and the bottom of the piston rod (34) is fixed to the bottom of the second tube (40). It also includes an energy storage device (70), which has a storage chamber inside; It also includes a second piston (71) that is slidably disposed in the storage cavity of the energy storage device (70), the second piston (71) dividing the storage cavity into a liquid storage cavity (72) and a gas storage cavity (73); It also includes a flow channel (50), and the liquid storage chamber (72) is connected to the upper liquid chamber (31) of the first tube (30) through the flow channel (50); It also includes a liquid valve (60) connected in series on the flow channel (50) for opening or closing the flow channel (50) to control the flow of liquid between the liquid storage chamber (72) and the upper liquid chamber (31).

2. The electric lifting device for an office chair according to claim 1, characterized in that: The liquid valve (60) is a normally closed solenoid valve.

3. The electric lifting device for an office chair according to claim 1, characterized in that: The liquid valve (60) is installed between the energy storage device (70) and the flow channel (50).

4. The electric lifting device for an office chair according to claim 1, characterized in that: A first sealing ring (331) is provided between the outer periphery of the first piston (33) and the inner wall of the first tube (30).

5. The electric lifting device for an office chair according to claim 1, characterized in that: A second sealing ring (711) is provided between the outer periphery of the second piston (71) and the inner wall of the storage cavity.

6. The electric lifting device for an office chair according to claim 1, characterized in that: Flanges (80) are provided at the outlet of the liquid storage chamber (72) of the energy storage device (70), the inlet and outlet of the liquid valve (60), both ends of the flow channel (50) and the inlet of the upper liquid chamber (31) of the first pipe (30). Each component is fixedly connected by the cooperation of the flanges (80) and bolts.

7. The electric lifting device for an office chair according to claim 1, characterized in that: It also includes a limiting structure to prevent the first tube (30) and the second tube (40) from rotating relative to each other. The limiting structure includes a long key (35) on the outer wall of the first tube (30) and a keyway (41) on the inner wall of the second tube (40). The long key (35) and the keyway (41) cooperate with each other.

8. The electric lifting device for an office chair according to claim 1, characterized in that: The bottom of the first tube (30) is provided with a sealing cap (36), which is axially sleeved on the piston rod (34) to prevent the first piston (33) from coming out of the first tube (30).

9. The electric lifting device for an office chair according to claim 1, characterized in that: The lower rod cavity (32) is filled with lubricating oil, which adheres between the outer peripheral wall of the first piston (33) and the inner wall of the first tube (30).

10. An electric lifting device for an office chair according to claim 1, characterized in that: The energy storage device (70) is pre-installed with an air filling port (74) that connects to the gas storage chamber (73).

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