Aluminum alloy die-casting shifting fork actuator with built-in cam for limiting
By incorporating a built-in cam limiting structure and a guided lubrication design, the shortcomings of the fork-type pneumatic actuator in terms of compatibility with different valves and control accuracy are solved, enabling precise control and stable transmission of ball valves and butterfly valves.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2026-04-14
AI Technical Summary
Existing pneumatic actuators cannot simultaneously accommodate the opening and closing angles of different valves, resulting in insufficient control accuracy and failing to meet the adaptation requirements of valves such as ball valves and butterfly valves.
The aluminum alloy die-cast shift fork actuator with built-in cam limit is used. By fitting a limit sleeve and limit bolt on the outside of the shift fork shaft, combined with a guide belt and self-lubricating bushing, it can achieve precise control and lubrication of the shift fork shaft rotation, thereby enhancing the structural rigidity and stability.
It enables adaptation to the opening and closing angles of different valves, improves control accuracy, reduces mechanical vibration and friction damage, extends service life, and adapts to stable control under high torque conditions.
Smart Images
Figure CN224120746U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of shift fork actuators, and specifically relates to an aluminum alloy die-cast shift fork actuator with built-in cam limiting. Background Technology
[0002] Currently, the fork-type pneumatic actuator is a piston-type actuator suitable for the on / off or metering control of valves with a 90° rotation angle (such as ball valves, butterfly valves, and plug valves). Pneumatic actuators have two types of transmission mechanisms: rack and pinion and fork-type. In a fork-type pneumatic actuator, the linear motion of the piston rod drives the fork to rotate, which in turn drives the main shaft or valve stem to rotate.
[0003] The existing pneumatic actuator with a shift fork mainly includes a cylinder component and a shift fork transmission component. The cylinder component includes a cylinder, a cylinder head, a piston, and a piston rod. The shift fork transmission component includes a shift fork assembly, a shift fork shaft, and a housing. The shift fork shaft and the shift fork assembly are housed in the housing. The shift fork shaft and the housing are rotatably connected. The shift fork assembly is drively connected to the piston rod.
[0004] However, existing pneumatic actuators with different types of valves have different rotation angles when the fork shaft rotates. The rotation angle of the fork shaft is not subject to any limit constraints, which cannot meet the opening and closing angle adaptation requirements of different valves (such as ball valves and butterfly valves), and the valve control accuracy cannot be met. Utility Model Content
[0005] This utility model proposes an aluminum alloy die-cast shift fork actuator with built-in cam limit, which solves the problem that the existing shift fork pneumatic actuator cannot meet the opening and closing angle adaptation requirements of different valves (such as ball valves and butterfly valves) when the shift fork shaft rotates, and cannot meet the accuracy requirements for controlling the rotation of the shift fork shaft.
[0006] The technical solution of this utility model is implemented as follows:
[0007] An aluminum alloy die-cast shift fork actuator with built-in cam limiting includes a cylinder body. A shift fork shaft is rotatably connected to the center of the cylinder body. A limiting sleeve is fixedly fitted on the outer side of the shift fork shaft. The limiting sleeve has two protrusions spaced apart circumferentially. Two limiting bolts are movably inserted into the outside of the cylinder body. Both limiting bolts are threadedly connected to the cylinder body. The two limiting bolts are located on the same side of the cylinder body. The ends of the two limiting bolts are respectively inserted into the inside of the cylinder body and contact the two protrusions for limiting.
[0008] Through the above technical solution, the matching and limiting between the protrusion and the limiting bolt can meet the opening and closing angle adaptation requirements of different valves (such as ball valves and butterfly valves) and improve control accuracy.
[0009] Optionally, the upper end of the shift fork shaft extends through the outer wall of the cylinder head, and a guide belt is sleeved on the upper end of the shift fork shaft. The guide belt is located at the contact point between the shift fork shaft and the cylinder body. A self-lubricating bushing is provided at the lower end of the shift fork shaft. The self-lubricating bushing is located at the contact point between the shift fork shaft and the cylinder body.
[0010] Through the above technical solutions, the guide belt and self-lubricating bushing can improve the transmission accuracy and stability during the rotation of the shift fork shaft.
[0011] Optionally, the guide strip is made of phenolic resin.
[0012] Through the above technical solution, the guide belt is made of phenolic resin, which gives the guide belt high compressive strength and the ability to suppress mechanical vibration, thereby reducing the damage of lateral forces to the actuator.
[0013] Optionally, the self-lubricating bushing is made of a composite material of bronze-based and PTFE.
[0014] Through the above technical solution, the self-lubricating bushing reduces the coefficient of friction through the PTFE layer, and the bronze substrate accelerates heat dissipation, thus avoiding high-temperature jamming.
[0015] Optionally, the protrusion is integrally formed with the limiting sleeve.
[0016] The above technical solution integrates the protrusion with the limiting sleeve, which improves the strength and stability of the protrusion.
[0017] Optionally, the protrusion is in the shape of an isosceles trapezoid.
[0018] Optionally, the cylinder block is integrally die-cast from aluminum alloy.
[0019] Through the above technical solutions, the cylinder body is die-cast, which reduces material redundancy, lowers the overall weight, and the one-piece molding avoids potential weaknesses in welds or joints, enhances structural rigidity, and the lighter cylinder body is easier to install. At the same time, the high strength is adapted to the high torque requirements of large-diameter valves.
[0020] Optionally, cylinder heads are detachably connected to both ends of the cylinder body via bolts.
[0021] Optionally, the lower end of the cylinder body is provided with a lower flange, the lower end of the shift fork shaft is located inside the lower flange, and the bottom of the lower flange is provided with a positioning stop and a standard anti-rotation keyway. The positioning stop is annular and communicates with the standard anti-rotation keyway.
[0022] The above technical solutions ensure the coaxiality of the actuator and valve by using a positioning stop, reducing assembly errors. The standard anti-rotation keyway prevents relative displacement between the actuator and valve under high torque conditions (such as the full differential pressure opening and closing of a ball valve), ensuring control stability.
[0023] After adopting the above technical solution, the beneficial effects of this utility model are:
[0024] 1. The cam-limiting structure in this utility model supports ±5° adjustment of the valve's opening and closing angle. This cam-limiting structure meets the opening and closing angle adaptation requirements of different valves (such as ball valves and butterfly valves), improving control accuracy. A steel self-locking threaded sleeve is inlaid within the limiting thread. This steel threaded sleeve enhances the limiting structure's impact resistance and prevents thread wear or loosening under repeated operation. The self-locking threaded sleeve prevents limiting offset caused by vibration, extending service life.
[0025] 2. In this utility model, a guide belt is fitted onto the upper end of the shift fork shaft, and a self-lubricating bushing is provided at the lower end of the shift fork shaft. The guide belt has the function of absorbing radial load, and its high compressive strength suppresses mechanical vibration and reduces damage to the actuator from lateral forces. The self-lubricating bushing has the functions of lubrication and heat dissipation. The self-lubricating bushing is made of a composite material of bronze matrix and PTFE. The PTFE layer reduces the coefficient of friction, and the bronze matrix accelerates heat dissipation, preventing high-temperature jamming. The self-lubricating bushing is made of lead-free material and has a wear-resistant design to meet harsh working conditions (such as chemical and energy fields), reducing maintenance frequency. The tight fit clearance (0.05~0.1mm) of the self-lubricating bushing meets the position feedback accuracy requirements of the intelligent positioner.
[0026] 3. The positioning stop ensures the coaxiality of the actuator and the valve, reducing assembly errors; the anti-rotation keyway prevents relative displacement between the actuator and the valve under high torque conditions (such as the full differential pressure opening and closing of ball valves), ensuring control stability.
[0027] 4. The actuator cylinder body adopts an integrated die-cast aluminum alloy shell. The die-casting process reduces material redundancy and overall weight. The one-piece molding avoids potential weaknesses in welds or joints, enhances structural rigidity, and the actuator has a lighter shell for easy installation. At the same time, its high strength adapts to the high torque requirements of large-diameter valves. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0029] Figure 1 This is a perspective view of the actuator in the embodiment;
[0030] Figure 2 This is a perspective view of the actuator (excluding the cylinder) in the embodiment;
[0031] Figure 3 This is a schematic diagram of the structure of the fork shaft, the limiting sleeve, the protrusion and the limiting bolt in the embodiment;
[0032] Figure 4 This is a cross-sectional view of the actuator in the embodiment;
[0033] Figure 5 This is a schematic diagram of the structure at the bottom of the actuator in the embodiment;
[0034] Figure 6 This is a side view of the actuator in the embodiment.
[0035] Explanation of reference numerals in the attached drawings: 1. Cylinder block; 2. Cylinder head; 3. Shift fork shaft; 4. Limit sleeve; 5. Protrusion; 6. Limit bolt; 7. Guide belt; 8. Self-lubricating bushing; 9. Lower flange; 10. Positioning stop; 11. Standard anti-rotation keyway. Detailed Implementation
[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0037] This application discloses an aluminum alloy die-cast shift fork actuator with built-in cam limiting.
[0038] Example
[0039] according to Figures 1 to 6 As shown, an aluminum alloy die-cast shift fork actuator with built-in cam limiting includes a cylinder body 1 and a cylinder head 2. The cylinder body 1 is integrally die-cast from aluminum alloy. The die-casting of the cylinder body 1 reduces material redundancy and overall weight. The integral molding avoids potential weaknesses in welds or joints, enhances structural rigidity, and the lighter cylinder body 1 facilitates installation. At the same time, its high strength adapts to the high torque requirements of large-diameter valves.
[0040] Cylinder heads 2 are detachably connected to both ends of cylinder body 1. A shift fork shaft 3 is rotatably connected to the center of cylinder body 1. The upper end of the shift fork shaft 3 extends through the outer wall of cylinder head 2. A guide belt 7 is fitted onto the upper end of the shift fork shaft 3, located at the contact point between the shift fork shaft 3 and cylinder body 1. The guide belt 7 is made of phenolic resin. A self-lubricating bushing 8 is located at the lower end of the shift fork shaft 3, also at the contact point between the shift fork shaft 3 and cylinder body 1. The self-lubricating bushing 8 is made of a composite material of bronze and PTFE. The phenolic resin material of the guide belt 7 provides high compressive strength and suppresses mechanical vibration, reducing damage to the actuator from lateral forces. The self-lubricating bushing 8 reduces the coefficient of friction through the PTFE layer, while the bronze substrate accelerates heat dissipation, preventing high-temperature jamming. The lead-free material and wear-resistant design of the self-lubricating bushing 8 meet the demands of harsh operating conditions (such as chemical and energy fields), reducing maintenance frequency.
[0041] The cylinder body 1 is equipped with a cam limiting structure, which includes a limiting sleeve 4, a limiting protrusion 5, and a limiting bolt 6. The limiting sleeve 4 is fixedly fitted on the outside of the shift fork shaft 3. The limiting sleeve 4 has two protrusions 5 spaced apart circumferentially. The protrusions 5 are integrally formed with the limiting sleeve 4 and are in the shape of an isosceles trapezoid. Two limiting bolts 6 are movably inserted into the outside of the cylinder body 1. Both limiting bolts 6 are threaded to the cylinder body 1 and are located on the same side of the cylinder body 1. The ends of the two limiting bolts 6 are inserted into the inside of the cylinder body 1 and contact the two protrusions 5. When the shift fork shaft 3 rotates, it drives the limiting sleeve 4 to rotate synchronously. At the same time, the limiting sleeve 4 drives the two protrusions 5 to rotate synchronously. During the rotation, the two protrusions 5 contact the ends of the two limiting bolts 6 respectively, thereby limiting the rotation angle of the shift fork shaft 3. When one of the protrusions 5 contacts the end of the corresponding limiting bolt 6, the shift fork shaft 3 stops rotating in that direction. The cam-based limiting structure supports ±5° adjustment of the opening and closing angle. The fit between the protrusion 5 and the limiting bolt 6 ensures the appropriate opening and closing angle for different valves (such as ball valves and butterfly valves), improving control accuracy. The limiting bolt 6 is made of steel, which enhances the impact resistance of the limiting structure and prevents thread wear or loosening under repeated operation.
[0042] The lower end of the cylinder body 1 is provided with a lower flange 9, and the lower end of the shift fork shaft 3 is located inside the lower flange 9. The bottom of the lower flange 9 is provided with a positioning stop 10 and a standard anti-rotation keyway 11. The positioning stop 10 is annular and is connected to the standard anti-rotation keyway 11.
[0043] The positioning stop 10 ensures the coaxiality of the actuator and the valve, reducing assembly errors. The standard anti-rotation keyway 11 prevents relative displacement between the actuator and the valve under high torque conditions (such as the full differential pressure opening and closing of a ball valve), ensuring control stability. During valve design and production, a boss and keyway can be manufactured to fit tightly with the positioning stop and keyway of the actuator during assembly. Valve and actuator assembly is existing technology and will not be elaborated here.
[0044] The tight fit clearance (0.05–0.1 mm) of the self-lubricating bushing 8 meets the position feedback accuracy requirements of the intelligent positioner. This tight fit clearance (0.05–0.1 mm) is measured using a fitting fixture controlled by drawing tolerances, which is existing technology and will not be elaborated upon here.
[0045] The specific structure and implementation process of the shift fork pneumatic actuator are existing technologies and will not be elaborated here. This utility model only makes some structural improvements based on the existing shift fork pneumatic actuator.
[0046] The actuator in this invention solves the core problems of traditional actuators, such as heavy weight, unreliable limiting, short life due to insufficient lubrication, and installation slippage under high torque conditions, through material design, structural optimization, and tribological improvements. At the same time, it improves compatibility with intelligent positioners and meets the needs of modern industry for high reliability, low maintenance, and intelligent control.
[0047] In the description of this utility model, it should be understood that the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise specified and limited, it should be noted that the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components, and can be direct connections or indirect connections through an intermediate medium. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.
[0048] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the technical solution of the present utility model should be included within the protection scope of the present utility model.
Claims
1. An aluminum alloy die cast shift fork actuator with built-in cam limit, characterized by: The device includes a cylinder body, with a shift fork shaft rotatably connected to the center of the cylinder body. A limiting sleeve is fixedly fitted on the outer side of the shift fork shaft. The limiting sleeve has two protrusions spaced apart circumferentially. Two limiting bolts are movably inserted into the outside of the cylinder body. Both limiting bolts are threadedly connected to the cylinder body and are located on the same side of the cylinder body. The ends of the two limiting bolts are respectively inserted into the inside of the cylinder body and contact the two protrusions for limiting.
2. The aluminum alloy die-cast shift fork actuator with built-in cam limiting according to claim 1, characterized in that: Both ends of the cylinder are detachably connected to cylinder heads by bolts. The upper end of the shift fork shaft extends through the outer wall of the cylinder head. A guide belt is fitted on the upper end of the shift fork shaft, and the guide belt is located at the contact point between the shift fork shaft and the cylinder. A self-lubricating bushing is provided at the lower end of the shift fork shaft, and the self-lubricating bushing is located at the contact point between the shift fork shaft and the cylinder.
3. The aluminum alloy die-cast shift fork actuator with built-in cam limiting according to claim 2, characterized in that: The guide belt is made of phenolic resin.
4. The aluminum alloy die-cast shift fork actuator with built-in cam limiting according to claim 2, characterized in that: The self-lubricating bushing is made of a composite material of bronze and PTFE.
5. The aluminum alloy die-cast shift fork actuator with built-in cam limiting according to claim 1, characterized in that: The protrusion is integrally formed with the limiting sleeve.
6. The aluminum alloy die-cast shift fork actuator with built-in cam limiting according to claim 1, characterized in that: The protrusion is in the shape of an isosceles trapezoid.
7. The aluminum alloy die-cast shift fork actuator with built-in cam limiting according to claim 1, characterized in that: The cylinder block is made of aluminum alloy through die casting.
8. The aluminum alloy die-cast shift fork actuator with built-in cam limiting according to claim 1, characterized in that: The lower end of the cylinder body is provided with a lower flange, and the lower end of the shift fork shaft is located inside the lower flange. The bottom of the lower flange is provided with a positioning stop and a standard anti-rotation keyway. The positioning stop is annular and communicates with the standard anti-rotation keyway.