A direct stroke electric actuator with high-precision adjustment

Abstract

The present invention relates to the technical field of automatic control equipment, and specifically proposes a direct stroke electric actuator with high-precision adjustment; it includes an actuator body and a flexible coupling assembled on the push rod of the actuator body. The flexible coupling includes an upper connecting part and a lower connecting part, and the flexible coupling is used to buffer the external load borne by the actuator body during operation; by setting the flexible coupling to replace the conventional hard connection docking structure generally used between the push rod of the electric actuator and the valve stem of the valve, the flexible coupling can not only achieve the series drive between the push rod and the valve stem, but also form a buffer isolation between the push rod and the valve stem, and can fully buffer the resultant load composed of the axial force and the radial force received by the actuator during operation, and can optimize and disperse the stress distribution, indirectly improving the bending resistance of the push rod and the valve stem, and also indirectly ensuring and improving the stability and precision of the actuator during long-term operation.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic control equipment, and specifically proposes a linear electric actuator with high-precision adjustment. Background Art

[0002] A linear electric actuator refers to a type of actuator that uses electric drive and converts an electrical signal into a linear displacement mechanical output, and is used to drive various types of valves, switching devices, or other mechanical equipment that requires linear motion; in the present invention, it specifically refers to driving various valves that require linear displacement control, such as globe valves, gate valves, etc., and is used in a pipeline system that requires high-precision adjustment of the valve flow rate. This type of linear electric actuator is generally directly installed on the valve, and the stroke push rod of the actuator is connected to the valve stem of the valve.

[0003] For existing linear electric actuators, the connection between the stroke push rod and the valve stem basically adopts a hard connection method such as threaded connection or bolt connection, and the stroke push rod and the valve stem form a stressed whole; when the actuator drives the valve stem to move linearly, the stroke push rod and the valve stem generally receive the action of axial force and radial force together, and mainly receive axial force. Without considering the axial force generated by the actuator itself on the push rod, the axial force mainly comes from the force for overcoming external loads such as valve sealing force and mechanical resistance, and also comes from the impact of inertial force; while the radial force mainly comes from the lateral impact caused by the flow force of the fluid in the pipeline, and also includes the radial component generated by mechanical resistance. The resultant force of the axial force and the radial force will act together on the stroke push rod and the valve stem that form a hard connection. During long-term operation of the actuator body, when it is often in a large-load or even overloaded working state, it will probably cause bending deformation or fatigue damage of the stroke push rod and the valve stem, etc., which not only affects the service life of the actuator body, but also aggravates the abnormal wear of the internal sealing structure of the valve, and then affects the sealing performance of the valve and the accuracy of the actuator body for valve adjustment and control.

[0004] In the prior art, usually by adding a guiding fit of a guide sleeve and a guide post, it is used to enhance the straightness of the stroke push rod and improve the stability and bending resistance of the stroke push rod during operation. However, in actual work, in the state of hard connection between the stroke push rod and the valve stem, the effect of the above solution is limited and cannot solve the above-mentioned problems to a great extent. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a linear electric actuator with high-precision adjustment, which is used to solve the problems mentioned in the above background art.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A direct-stroke electric actuator with high-precision adjustment, including an actuator body and a flexible coupling assembled on the push rod of the actuator body. The flexible coupling includes:

[0007] An upper connecting part, including a flange sleeve detachably fixed on the push rod and an external cylinder fixed at the bottom end of the flange sleeve. An internal cylinder sleeved on the push rod is arranged in the external cylinder. The internal cylinder is surrounded by a plurality of single-piece cylinder blocks that are disconnected and independently arranged and are installed on the push rod through key fitting. A lateral buffer layer for buffering radial force is arranged between each single-piece cylinder block and the inner wall of the external cylinder. The external cylinder presses the single-piece cylinder block against the push rod through the lateral buffer layer, and the single-piece cylinder block has a degree of freedom of movement in the radial direction of the external cylinder. A tray is detachably installed at the bottom end of the push rod, and a buffer gap is left between the tray and the bottom end of the internal cylinder.

[0008] And a lower connecting part, including a transition cylinder arranged below the internal cylinder and a docking cylinder detachably fixed at the bottom end of the transition cylinder. The tray is located in the transition cylinder, and a vertical buffer layer for buffering axial force is arranged in the buffer gap in the transition cylinder. The vertical buffer layer contacts the lower end of the external cylinder and the upper end of the tray; the bottom ends of the plurality of single-piece cylinder blocks sequentially pass through the vertical buffer layer and the tray, and are commonly connected to an elastic frame, and the elastic frame is fixed in the transition cylinder.

[0009] Preferably, the lateral buffer layer is a buffer block embedded and fixed on the inner wall of the external cylinder and made of a flexible material, and the single-piece cylinder block is fitted and clamped on the corresponding buffer block in a profile manner.

[0010] Preferably, an inner convex ring is concentrically arranged on the inner wall of the transition cylinder; the vertical buffer layer is a buffer spacer made of a flexible material and in a circular ring shape. The buffer spacer is sleeved on the bottom of the push rod and is coated and fixed on the inner convex ring.

[0011] Preferably, a lower guide pin is vertically fixed at the bottom end of the single-piece cylinder block, and a plurality of lower guide holes corresponding to the plurality of single-piece cylinder blocks are opened on the tray surface. The lower guide holes are elongated holes extending in the radial direction of the tray. The lower guide pin passes through the buffer spacer and the corresponding lower guide hole, and the bottom end of the lower guide pin is fixed on the elastic frame.

[0012] Preferably, an upper guide pin is vertically fixed at the top end of the single-piece cylinder block, and a plurality of upper guide holes corresponding to the plurality of single-piece cylinder blocks are opened on the flange of the flange sleeve. The upper guide holes are elongated holes extending in the radial direction of the flange sleeve. The upper guide pin moves along the corresponding upper guide hole.

[0013] Preferably, the elastic frame includes a fixed ring fixed on the inner wall of the transition cylinder and a plurality of spring pieces fixed on the fixed ring. The plurality of spring pieces are respectively fixed at the bottom ends of the plurality of lower guide pins.

[0014] Preferably, the flange sleeve is a split structure, and the two split structures of the flange sleeve are both sleeved on the push rod by key fitting.

[0015] Preferably, a positioning shaft is coaxially arranged at the bottom end of the push rod, and the buffer spacer is sleeved on the positioning shaft; an annular groove with a circumferential cutting structure is arranged on the side wall of the buffer spacer, and the inner convex ring is embedded in the annular groove.

[0016] Preferably, an internal threaded hole is axially formed in the push rod from the bottom end, and a screw rod assembled in the internal threaded hole is fixed at the center of the tray.

[0017] Preferably, a plurality of embedded blocks cooperating with the plurality of buffer blocks are circumferentially distributed on the inner wall of the external cylinder, and an embedded groove for the embedded blocks to be embedded is arranged on the buffer block.

[0018] The above technical solution has the following advantages or beneficial effects: The present invention provides a linear stroke electric actuator that can be adjusted with high precision. By setting a flexible coupling to replace the conventional hard connection docking structure generally used between the push rod of an electric actuator and the valve stem of a valve, the flexible coupling can not only achieve the series drive between the push rod and the valve stem, but also form a buffer isolation between the push rod and the valve stem, and can fully buffer the resultant load composed of the axial force and the radial force received during the operation of the actuator, and can optimize and disperse the stress distribution, avoid local stress concentration on structures such as the push rod and the valve stem, improve the large load bearing capacity of the actuator, indirectly improve the bending resistance of the push rod and the valve stem, reduce the probability of bending and fatigue damage of the push rod and the valve stem, ensure the straightness of the linear stroke displacement of the actuator, improve the service life, and also indirectly ensure and improve the stability and precision of the adjustment during the long-term operation of the actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, the present invention and its features, shape, and advantages will become more obvious. The same reference numerals indicate the same parts in all the drawings, and the drawings are not deliberately drawn to scale, with the focus on showing the gist of the present invention.

[0020] Figure 1 is a three-dimensional structural schematic diagram of a linear stroke electric actuator that can be adjusted with high precision provided by the present invention.

[0021] Figure 2 is a front view of a linear stroke electric actuator that can be adjusted with high precision provided by the present invention.

[0022] Figure 3 is a three-dimensional sectional view of the flexible coupling.

[0023] Figure 4 is a three-dimensional sectional view of a partial assembly structure of the flexible coupling.

[0024] Figure 5 It is a three-dimensional structure diagram of the push rod.

[0025] Figure 6 It is a three-dimensional structure diagram of the flange sleeve.

[0026] Figure 7 It is a three-dimensional sectional view of the buffer block and the outer cylinder assembly.

[0027] Figure 8 It is a three-dimensional sectional view of the outer cylinder.

[0028] Figure 9 It is a three-dimensional structure diagram of the inner cylinder.

[0029] Figure 10 It is a three-dimensional structure diagram of the tray.

[0030] Figure 11 It is a three-dimensional sectional view of the lower connection part.

[0031] Figure 12 It is a three-dimensional structure diagram of the elastic support and the transition cylinder assembly.

[0032] In the figure: 1. Actuator body; 11. Push rod; 111. Clamping key; 112. Positioning key; 113. Positioning shaft; 12. Connecting guide frame; 13. Guide slider; 2. Flexible coupling; 3. Upper connection part; 31. Flange sleeve; 311. Upper guide hole; 32. Outer cylinder; 321. Embedded block; 33. Inner cylinder; 331. Single-petal cylinder block; 332. Upper guide pin; 333. Lower guide pin; 34. Buffer block; 341. Embedded groove; 35. Tray; 351. Screw; 352. Lower guide hole; 4. Lower connection part; 41. Transition cylinder; 411. Inner convex ring; 412. Square plate end; 42. Docking cylinder; 421. Square cover; 422. Inner threaded cylinder; 43. Buffer spacer; 431. Annular groove; 432. Avoidance hole; 44. Elastic support; 441. Fixed ring; 442. Spring piece. Detailed implementation manners

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] In order to enable those in the technical field to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] As Figure 1 andFigure 2 As shown, a linear electric actuator with high-precision adjustment includes an actuator body 1 and a flexible coupling 2 assembled on a push rod 11 of the actuator body 1, which is docked with the valve stem of a corresponding controlled valve through the flexible coupling 2. A connecting guide frame 12 is welded to the bottom of the actuator body 1. The connecting guide frame 12 includes a fixed base that can be fixed to the valve by bolts and two guide columns vertically welded to the fixed base. To improve the stability and guiding property of the movement of the push rod 11, a guiding slider 13 is welded on the push rod 11, and the guiding slider 13 is slidably installed between the two guide columns of the connecting guide frame 12.

[0036] As Figure 4 and Figure 5 shown, in order to cooperate with the installation of the flexible coupling 2, two oppositely arranged positioning keys 112 are provided below the guiding slider 13 on the push rod 11. Eight clamping keys 111 are circumferentially and evenly distributed below the two positioning keys 112 on the push rod 11. A positioning shaft 113 is coaxially arranged at the bottom end of the push rod 11; the push rod 11 is integrally processed and formed.

[0037] As Figure 2 , Figure 3 and Figure 6 shown, the flexible coupling 2 is composed of an upper connecting part 3 docked with the push rod 11 and a lower connecting part 4 docked with the valve stem; the upper connecting part 3 includes a flange sleeve 31, an outer cylinder 32, an inner cylinder 33, a buffer block 34, and a tray 35; for the convenience of assembly, the flange sleeve 31 is a split structure. The two split structures of the flange sleeve 31 are both matched with the positioning keys 112 and are sleeved on the push rod 11. The two split structures of the flange sleeve 31 are locked by bolts, and the two split structures and the push rod 11 are fixed by screws.

[0038] As Figure 4 , Figure 7 and Figure 8 shown, the top end of the outer cylinder 32 is provided with a flange that is butt-jointed with the flange of the flange sleeve 31, and the two flanges are locked and fixed by bolts. Eight embedded blocks 321 are circumferentially and evenly distributed on the inner wall of the outer cylinder 32. The embedded blocks 321 are integrally processed and formed with the outer cylinder 32. The embedded blocks 321 are in the shape of rectangular blocks. A buffer block 34 is assembled on each embedded block 321. An embedded groove 341 for the embedded block 321 to be embedded is provided on the buffer block 34. The buffer block 34 is nested on the embedded block 321 through the embedded groove 341, and the buffer block 34 is in close contact with the inner wall of the outer cylinder 32. In this embodiment, the buffer block 34 is made of rubber material.

[0039] As Figure 3 , Figure 4 and Figure 9As shown, an inner cylinder 33 sleeving on a push rod 11 is arranged inside an outer cylinder 32. The inner cylinder 33 is formed by enclosing eight disconnected and independently arranged single - petal cylinder blocks 331. The eight single - petal cylinder blocks 331 are respectively assembled on eight buffer blocks 34 one by one. A profile surface capable of being clamped and fitted tightly with each other is arranged between the single - petal cylinder block 331 and the buffer block 34. The single - petal cylinder block 331 is clamped on the corresponding buffer block 34. The eight single - petal cylinder blocks 331 are also respectively clamped on eight clamping keys 111 one by one. The outer cylinder 32 presses the single - petal cylinder block 331 tightly and sleeved on the push rod 11 through the buffer block 34. Each buffer block 34 independently forms a lateral buffer layer located between each single - petal cylinder block 331 and the outer cylinder 32 and used for buffering radial force.

[0040] As Figure 3 , Figure 4 , Figure 6 and Figure 10 shown, an internal threaded hole is axially formed in the push rod 11 from the bottom end of the positioning shaft 113. A screw rod 351 is fixedly installed at the center of the tray 35 through a screw. The tray 35 is installed in the internal threaded hole through threaded fit of the screw rod 351; and a buffer gap is left between the tray 35 and the bottom end of the inner cylinder 33. The flange sleeve 31, the outer cylinder 32 and the tray 35 are coaxially assembled; in this embodiment, the upper and lower ends of the single - petal cylinder block 331 are flush with the upper and lower ends of the outer cylinder 32 respectively. Upper guide pins 332 and lower guide pins 333 are vertically fixed at the top and bottom ends of the single - petal cylinder block 331 respectively. The upper guide pins 332 and the lower guide pins 333 are integrally formed with the single - petal cylinder block 331. Eight upper guide holes 311 corresponding to the eight upper guide pins 332 one by one are formed on the flange of the flange sleeve 31. Eight lower guide holes 352 corresponding to the eight lower guide pins 333 one by one are formed on the tray surface of the tray 35. The upper guide holes 311 and the lower guide holes 352 are both extended holes extending in the radial direction of the outer cylinder 32. The upper guide pin 332 moves along the corresponding upper guide hole 311, and the lower guide pin 333 passes through the corresponding lower guide hole 352 and moves along the lower guide hole 352. Because a sandwich layer formed by buffer blocks 34 is arranged between each single - petal cylinder block 331 and the outer cylinder 32, and the upper and lower ends of the single - petal cylinder block 331 are respectively guided and moved corresponding to the flange sleeve 31 and the tray 35 through the upper guide pin 332 and the lower guide pin 333, each single - petal cylinder block 331 has the freedom to move in the radial direction of the outer cylinder 32, and each buffer block 34 has a tendency to be compressed and buffered due to the movement of the single - petal cylinder block 331.

[0041] As Figure 3 , Figure 4 , Figure 11 and Figure 12As shown in the figure, the lower connection part 4 includes a transition cylinder 41, a docking cylinder 42, a buffer spacer 43 and an elastic support 44; the transition cylinder 41 is arranged below the external cylinder 32, and an integrally formed inner convex ring 411 is concentrically arranged on the inner wall of the transition cylinder 41; the buffer spacer 43 is in a circular ring shape, made of rubber material, and an annular groove 431 with a circumferential cutting structure is arranged on the side wall of the buffer spacer 43. The buffer spacer 43 is sleeved on the positioning shaft 113, and the inner convex ring 411 is embedded in the annular groove 431. The buffer spacer 43 covers the inner convex ring 411; the tray 35 is located in the transition cylinder 41, and the buffer spacer 43 is located in the buffer gap to form a vertical buffer layer for buffering axial force. The buffer spacer 43 is clamped in contact between the lower end of the external cylinder 32 and the upper end of the tray 35; avoidance holes 432 are correspondingly arranged on the buffer spacer 43 for each lower guide pin 333, and the lower guide pin 333 vertically passes through the corresponding avoidance hole 432; the elastic support 44 includes a fixing ring 441 fixed on the inner wall of the transition cylinder 41 by screws and eight spring pieces 442 integrally formed on the fixing ring 441. The eight spring pieces 442 are fixedly connected to the bottom ends of the eight lower guide pins 333 by bolts one by one. The docking cylinder 42 includes a square cover 421 and an internal thread cylinder 422 fixed at the bottom end of the square cover 421. The square cover 421 is sleeved on the square plate end 412 and fixed by bolts. The internal thread cylinder 422 is used for docking with the valve stem.

[0042] The flexible coupling 2 provided by the present invention is used for docking and installing between the push rod 11 of the actuator body 1 and the valve stem of the valve. The docking and installation process can be divided into two major steps: pre-installation and formal installation. The following is an elaboration on the specific docking and installation process:

[0043] Pre-installation stage

[0044] In the upper connection part 3, first, the eight buffer blocks 34 are sequentially sleeved on the inner wall of the external cylinder 32, and then each single-piece cylinder block 331 is sequentially clamped on the buffer block 34 to form a first pre-assembled part.

[0045] In the lower connection part 4, the buffer spacer 43 is installed in the transition cylinder 41 to form a second pre-assembled part.

[0046] Formal installation stage

[0047] First, the connecting guide frame 12 is fixed at the installation position of the valve by bolts, so that the actuator body 1 is fixed on the valve.

[0048] Subsequently, the flange sleeve 31 is positioned and installed at the position of the positioning key 112 of the push rod 11 and locked. Then, the eight single-petal cylinder blocks 331 in the first pre-assembled part are vertically aligned with the eight clamping keys 111 on the push rod 11. The first pre-assembled part is pushed upward from the bottom end of the push rod 11, so that the single-petal cylinder blocks 331 slide upward along the clamping keys 111 until the flanges of the external cylinder 32 and the flange sleeve 31 are butt-jointed and locked by bolts.

[0049] Next, the second pre-assembled part is placed directly below the first pre-assembled part and rotated and adjusted so that the avoidance hole 432 of the buffer spacer 43 is aligned with the lower guide pin 333. Then, the second pre-assembled part is pushed upward so that the lower guide pin 333 passes through the avoidance hole 432, and the buffer spacer 43 is sleeved on the positioning shaft 113. Subsequently, the tray 35 is extended towards the transition cylinder 41, and the screw rod 351 is screwed into the internal thread hole of the push rod 11 so that the buffer spacer 43 is just clamped between the bottom end of the external cylinder 32 and the upper end of the tray 35.

[0050] Then, the elastic support 44 is extended into the transition cylinder 41, and the spring pieces 442 are sequentially locked to the bottom ends of the corresponding lower guide pins 333 by bolts, and the fixing ring 441 is fixed to the inner wall of the transition cylinder 41 by screws.

[0051] Regarding the installation of the docking cylinder 42, first, the valve stem is screwed and tightened into the internal thread cylinder 422, and through rotation and adjustment, the square cover 421 is aligned with the square plate end 412. Then, the push rod 11 is controlled by the actuator body 1 to move downward so that the square plate end 412 is aligned and pressed into the square cover 421. Finally, the square cover 421 is locked to the square plate end 412, thus completing the docking installation between the electric actuator provided by the present invention and the valve.

[0052] In the entire automatic control system, the actuator body 1 is connected to an external controller by wired or wireless means. During actual operation, the controller issues a command electrical signal, and the control circuit inside the actuator body 1 receives the electrical signal and analyzes and processes it. Then, according to the signal after analysis and processing, it controls and drives the built-in motor inside the actuator body 1, thereby driving the push rod 11 to move vertically. In the present invention, the push rod 11 indirectly drives the valve stem through the flexible coupling 2 to achieve valve control.

[0053] In the prior art, a rigid connection is generally adopted between the push rod 11 and the valve rod to form an integral unit that bears force together. During the operation of the actuator body 1, the push rod 11 and the valve rod will jointly bear the external load, and the resultant force of the external load can be decomposed into an axial force and a radial force. In the present invention, however, the push rod 11 and the valve rod are connected by a flexible coupling 2. Regarding the upper connecting part 3, the external cylinder 32 is integrally fixed on the push rod 11 through the flange sleeve 31, and the tray 35 is fixed on the push rod 11 through the screw 351. Therefore, the flange sleeve 31, the external cylinder 32, and the tray 35 and the push rod 11 form a rigid connection integral unit, named the upper integral part; regarding the lower connecting part 4, the transition cylinder 41 and the docking cylinder 42 and the valve rod form a rigid connection integral unit, named the lower integral part; when the actuator body 1 works, the lower integral part is in upper and lower clamping contact with the lower end of the external cylinder 32 and the upper end of the tray 35 in the upper integral part through the buffer spacer 43, and the axial force will be transmitted to the buffer spacer 43, and the buffer spacer 43 will buffer the axial force through passive compression. On the other hand, the single-lobe cylinder block 331 has a degree of freedom to move radially along the push rod 11 or the valve rod. Therefore, when bearing the radial force, the elastic support 44 and the buffer block 34 will jointly buffer the radial force. In addition, multiple single-lobe cylinders and the buffer blocks 34 are distributed around the push rod 11, which can greatly optimize and disperse the stress distribution and avoid local stress concentration; the flexible coupling 2 can not only achieve the series drive between the push rod 11 and the valve rod, but also form a buffer isolation between the push rod 11 and the valve rod, and can fully buffer the resultant force load composed of the axial force and the radial force received during the operation of the actuator, improve the large-load bearing capacity of the actuator, indirectly improve the bending resistance of the push rod 11 and the valve rod, reduce the probability of the push rod 11 and the valve rod being bent and suffering from fatigue damage, ensure the straightness of the linear displacement of the actuator, improve the service life, and also indirectly ensure and improve the stability and accuracy of the adjustment of the actuator during long-term operation.

[0054] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0055] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and defined, the terms "arranged", "connected", "installed", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0056] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and the devices and structures not described in detail should be understood to be implemented in a common manner in the art; any person skilled in the art can make many possible changes and modifications without departing from the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes, which does not affect the essence of the present invention. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A direct stroke electric actuator with high-precision adjustment, characterized in that, It includes an actuator body and a flexible coupling assembled on the push rod of the actuator body. The flexible coupling includes: an upper connection part, which includes a flange sleeve detachably fixed on the push rod and an external cylinder fixed at the bottom end of the flange sleeve. An internal cylinder sleeved on the push rod is arranged in the external cylinder. The internal cylinder is surrounded by a plurality of single-piece cylinder blocks that are disconnected and independently arranged and are installed on the push rod by key fitting. A lateral buffer layer for buffering radial force is arranged between each single-piece cylinder block and the inner wall of the external cylinder. The external cylinder presses the single-piece cylinder blocks against the push rod through the lateral buffer layer, and the single-piece cylinder blocks have a degree of freedom of movement in the radial direction of the external cylinder. A tray is detachably installed at the bottom end of the push rod, and a buffer gap is left between the tray and the bottom end of the internal cylinder; and a lower connection part, which includes a transition cylinder arranged below the internal cylinder and a docking cylinder detachably fixed at the bottom end of the transition cylinder. The tray is located in the transition cylinder, and a vertical buffer layer for buffering axial force is arranged in the buffer gap in the transition cylinder. The vertical buffer layer contacts the lower end of the external cylinder and the upper end of the tray; the bottom ends of the plurality of single-piece cylinder blocks sequentially pass through the vertical buffer layer and the tray and are commonly connected to an elastic frame, and the elastic frame is fixed in the transition cylinder; an internal threaded hole is axially formed in the push rod from the bottom end, and a screw rod assembled in the internal threaded hole is fixedly arranged at the center of the tray.

2. A direct stroke electric actuator with high-precision adjustment according to claim 1, characterized in that: The lateral buffer layer is a buffer block embedded and fixed on the inner wall of the external cylinder and made of a flexible material, and the single-piece cylinder block is fitted and clamped on the corresponding buffer block in a form-fitting manner.

3. A direct stroke electric actuator with high-precision adjustment according to claim 1, characterized in that: An inner convex ring is concentrically arranged on the inner wall of the transition cylinder; the vertical buffer layer is a buffer spacer made of a flexible material and in a circular ring shape. The buffer spacer is sleeved on the bottom of the push rod, and the buffer spacer is coated and fixed on the inner convex ring.

4. A direct stroke electric actuator with high-precision adjustment according to claim 3, characterized in that: A lower guide pin is vertically fixed at the bottom end of the single-piece cylinder block. A plurality of lower guide holes corresponding to the plurality of single-piece cylinder blocks are formed in the tray surface. The lower guide holes are elongated holes extending in the radial direction of the tray. The lower guide pin passes through the buffer spacer and the corresponding lower guide hole, and the bottom end of the lower guide pin is fixed on the elastic frame.

5. A direct stroke electric actuator with high-precision adjustment according to claim 4, characterized in that: An upper guide pin is vertically fixed at the top end of the single-piece cylinder block. A plurality of upper guide holes corresponding to the plurality of single-piece cylinder blocks are formed in the flange of the flange sleeve. The upper guide holes are elongated holes extending in the radial direction of the flange sleeve, and the upper guide pin moves along the corresponding upper guide hole.

6. A direct stroke electric actuator capable of high-precision adjustment according to claim 4, characterized in that: The elastic frame includes a fixed ring fixed on the inner wall of the transition cylinder and a plurality of spring pieces fixed on the fixed ring. The plurality of spring pieces are fixedly arranged at the bottom ends of the plurality of lower guide pins in a one-to-one correspondence.

7. A direct stroke electric actuator with high-precision adjustment according to claim 1, characterized in that: The flange sleeve is a split structure, and the two split structures of the flange sleeve are both sleeved on the push rod by key fitting.

8. A direct stroke electric actuator with high-precision adjustment according to claim 3, characterized in that: A positioning shaft is coaxially arranged at the bottom end of the push rod, and the buffer spacer is sleeved on the positioning shaft; an annular groove with a circumferential cutting structure is arranged on the side wall of the buffer spacer, and the inner convex ring is embedded in the annular groove.

9. A direct stroke electric actuator with high-precision adjustment according to claim 2, characterized in that: A plurality of embedded blocks cooperating with the plurality of buffer blocks are circumferentially distributed on the inner wall of the external cylinder, and an embedded groove for the embedded blocks to be embedded is arranged on the buffer block.

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