Double-piston type pneumatic shifting fork executing mechanism based on hydraulic proportional transmission

Abstract

The invention relates to the technical field of pneumatic shifting fork executing mechanisms, and discloses a double-piston type pneumatic shifting fork executing mechanism based on hydraulic proportional transmission, which comprises a box body, a crank is arranged in the box body, a guide sliding block is arranged in the middle of the crank, and a transmission pin penetrates through the crank and the guide sliding block from top to bottom; a guide through hole and a blind hole are formed in the guide sliding block, a guide rod penetrates through the guide through hole, and the left end of a push rod extends into the blind hole and is connected with the guide sliding block; the air cylinder cavity comprises an inner piston barrel and an outer piston barrel, and the push rod extends into the inner piston barrel and is connected with an inner piston assembled in the inner piston barrel; and an outer piston ring is assembled between the inner piston barrel and the outer piston barrel on the right side of the spring. The compression stroke of the spring is effectively shortened, and then the free length of the spring and the length of the whole executing mechanism are shortened; and the spring and the piston are simultaneously placed on the same side, so that the overall length of the actuating mechanism is further shortened, the space utilization rate is improved, and the use cost is effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pneumatic shift fork actuators, and more particularly to a double-piston pneumatic shift fork actuator based on hydraulic proportional transmission. BACKGROUND

[0002] An actuator is a device used to operate a valve and connected to the valve, which can be driven by fluid such as liquid, gas, or electricity, to open, close, or control the valve opening. Single-acting shift fork pneumatic actuators are a type of piston actuator. The opening action of the actuator is driven by a power source, and the closing action is provided by a reset power spring. It is suitable for 90° angle valves (such as ball valves, butterfly valves, and plug valves) for on-off or metering control.

[0003] Currently, the main problem of the existing single-acting shift fork pneumatic actuators on the market is as follows:

[0004] The existing single-acting shift fork actuators are limited by the free length and compression stroke of the spring, which is very long. However, the existing valves are relatively small, resulting in a mismatch between the structure of the single-acting shift fork actuator and the valve installation, low space utilization, material waste, increased use cost, and difficulty in installation in many relatively narrow systems.

[0005] Therefore, how to optimize the overall structure of the single-acting shift fork actuator, effectively shorten the spring compression stroke and free length, and thus shorten the overall actuator length, improve the installation utilization of the actuator, and break through the installation limitations of narrow space, has become a key technical challenge for researchers in the field of actuators. SUMMARY

[0006] Therefore, the present application proposes a double-piston pneumatic shift fork actuator based on hydraulic proportional transmission, and the specific technical solutions are as follows:

[0007] The double-piston pneumatic shift fork actuator based on hydraulic proportional transmission comprises a box body and a cylinder cavity, the cylinder cavity is sealedly installed on the right side of the box body, a crank for connecting an execution member is installed in the box body, a guide sliding block is arranged in the middle of the crank, a transmission pin penetrates the crank and the guide sliding block from top to bottom, a guide rod penetrates a guide through hole of the guide sliding block, and the two ends of the guide rod are fixedly connected with the inner wall of the box body, and the left end of a push rod penetrates into the blind hole and is connected with the guide sliding block, the cylinder cavity comprises an inner piston cylinder and an outer piston cylinder, the right end of the outer piston cylinder is fixedly connected with a right end cover, the right end of the inner piston cylinder is inserted into the inner wall of the right end cover, the left end of the inner piston cylinder and the outer piston cylinder are fixedly connected with a left end cover, and the left outer wall of the box body is connected with the left end cover, the push rod penetrates the box body and the left end cover and is fixedly connected with a push rod connecting plate, the push rod connecting plate is fixedly connected with a push rod connecting cylinder on the right side, the push rod connecting cylinder is fixedly connected with an inner piston assembled in the inner piston cylinder on the right side, a spring is sleeved on the outer side of the inner piston cylinder, an outer piston ring is assembled between the inner piston cylinder and the outer piston cylinder on the right side of the spring, an array of oil through holes are arranged on the side of the inner piston cylinder close to the right end cover, the oil through holes are connected with the hydraulic oil cavity in the inner piston cylinder and the outer piston cylinder, and an air inlet is arranged on the box body and the left end cover.

[0008] Preferably, the upper part of the box body is connected with an upper end cover through an upper end cover bolt and an upper end cover spring gasket, the right side wall of the box body is connected with the left end cover through a left end cover bolt, the lower end of the crank is rotatably connected with the box body through a lower wear ring and a lower thrust bearing, and the upper end of the crank is rotatably connected with the upper end cover through an upper wear ring and an upper thrust bearing.

[0009] Preferably, the right end of the inner piston cylinder is inserted into a corresponding insertion slot on the inner wall of the right end cover, and the right end of the inner piston cylinder is gap-fitted with the insertion slot on the inner wall of the right end cover, and / or an oil inlet is arranged at the center of the right end cover, the oil inlet is sealed by an oil inlet end cover, the oil inlet end cover and the right end cover are connected through an oil inlet end cover bolt, and the oil inlet end cover is sealed by an oil inlet end cover O-ring.

[0010] Preferably, the right end of the inner piston cylinder is inserted into a corresponding insertion slot on the inner wall of the right end cover, and the right end of the inner piston cylinder is gap-fitted with the insertion slot on the inner wall of the right end cover, and / or an oil inlet is arranged at the center of the right end cover, the oil inlet is sealed by an oil inlet end cover, the oil inlet end cover and the right end cover are connected through an oil inlet end cover bolt, and the oil inlet end cover is sealed by an oil inlet end cover O-ring.

[0011] Preferably, a spring guide plate one is fixed to the right inner wall of the left end cover, a spring guide plate two is fixed to the left inner wall of the outer piston ring, and the spring is located between the spring guide plate one and the spring guide plate two.

[0012] Preferably, an end cover hole is formed in the left end cover for the push rod to pass through, a first O-ring groove, a guide belt groove and a second O-ring groove are sequentially formed in the hole wall of the end cover hole from left to right, the push rod O-ring one is assembled in the first O-ring groove, the push rod guide belt is assembled in the guide belt groove, and the push rod O-ring two is assembled in the second O-ring groove; the inner piston O-ring groove and the inner piston guide belt groove are formed in the outer wall of the inner piston, the inner piston O-ring is assembled in the inner piston O-ring groove, and the inner piston guide belt is assembled in the inner piston guide belt groove; the outer piston ring O-ring groove and the outer piston ring guide belt groove are formed in the inner and outer walls of the outer piston ring, the outer piston ring O-ring is assembled in the outer piston ring O-ring groove, and the outer piston ring guide belt is assembled in the outer piston ring guide belt groove.

[0013] Preferably, a limiting screw for limiting the position of the crank is threadedly connected to the box.

[0014] Preferably, the outer surface of the transmission pin is sprayed with wear-resistant material, the upper end of the transmission pin is thin, the lower end of the transmission pin is thick, the upper end shoulder of the transmission pin is clamped on the crank, the lower end of the crank is provided with a transmission pin cover plate through a cover plate screw, and the transmission pin cover plate limits the lower end of the transmission pin from extending downwardly out of the crank.

[0015] Preferably, the inner wall of the right end cover is provided with a limiting stake extending to the left, and the pre-tightening force of the spring can press the outer piston ring against the limiting stake.

[0016] Preferably, a spring breathing hole is formed in the outer wall of the outer piston cylinder.

[0017] Compared with the prior art, the double-piston pneumatic fork actuator based on hydraulic proportional transmission has the following beneficial effects:

[0018] In the double-piston pneumatic shift fork actuator based on hydraulic proportional transmission of the present application, the space utilization is improved by embedding the outer piston ring in the inner piston; the jack and the hydraulic area difference principle are used, when the air is ventilated, the hydraulic oil is used as the force transmission medium, the outer piston ring is pushed by the inner piston and the spring is compressed (the push rod drives the crank to realize torque transmission, and the crank is connected with the actuator), the area difference between the outer piston ring and the inner piston is utilized, for example, when the area of the inner piston: the area of the outer piston ring = 1:2, the stroke of the inner piston: the stroke of the outer piston ring = 2:1, the spring compression stroke is effectively shortened, and the spring free length and the overall actuator length are shortened (originally, the spring can only be compressed by 200mm under the limitation of the compression stroke of the spring, and the push rod moves by 200mm; and the compression stroke of the spring in the present application is multiplied, a relatively short spring can be used, and the length is greatly shortened under the condition that the spring output force and torque are unchanged).

[0019] Moreover, the spring and the piston are placed on the same side in the present application, which further shortens the overall length of the actuator, improves the space utilization, and effectively reduces the use cost. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0021] Figure 1 It is an axonometric view of the double-piston pneumatic shift fork actuator based on hydraulic proportional transmission of the present application.

[0022] Figure 2 It is a top view of the double-piston pneumatic shift fork actuator based on hydraulic proportional transmission of the present application.

[0023] Figure 3 It is Figure 2 a sectional view in the direction of A-A.

[0024] Figure 3a It is Figure 3 an enlarged schematic view of the structure indicated by I. Figure 3b It is Figure 3 an enlarged schematic view of the structure indicated by II. Figure 3c It is Figure 3 an enlarged schematic view of the structure indicated by III. Figure 3d It is Figure 3 an enlarged schematic view of the structure indicated by IV.

[0025] Figure 4 It isFigure 2 Cross-sectional view along the direction of B-B;

[0026] Figure 4a For Figure 4 Enlarged schematic view of the structure indicated at VI; Figure 4b For Figure 4 Enlarged schematic view of the structure indicated at VI;

[0027] Figure 5 Front view of a double-piston pneumatic fork actuating mechanism based on hydraulic proportional transmission according to the present application;

[0028] Figure 6 For Figure 5 Cross-sectional view along the direction of C-C;

[0029] Figure 7a Internal operation schematic view of the actuating mechanism according to the present application when the crank is twisted to the leftmost end; Figure 7b Internal operation schematic view of the actuating mechanism according to the present application when the crank is twisted to the rightmost end;

[0030] Figure 8 Structure schematic view of the box in the actuating mechanism according to the present application;

[0031] Figure 9 Structure schematic view of the crank in the actuating mechanism according to the present application;

[0032] Figure 10 Structure schematic view of the transmission pin in the actuating mechanism according to the present application;

[0033] Figure 11 Assembly view of the crank, transmission pin and push rod;

[0034] Figure 12a Structure schematic view of the inner piston in the actuating mechanism according to the present application; Figure 12b Half cross-sectional view of the inner piston in the actuating mechanism according to the present application;

[0035] Figure 13a Structure schematic view of the outer piston ring in the actuating mechanism according to the present application; Figure 13b Half cross-sectional view of the outer piston ring in the actuating mechanism according to the present application;

[0036] Figure 14 Structure schematic view of the guide slider in the actuating mechanism according to the present application;

[0037] Figure 15 Structure schematic view of the inner piston cylinder in the actuating mechanism according to the present application;

[0038] Figure 16 Structure schematic view of the left end cover in the actuating mechanism according to the present application;

[0039] Figure 17Structure diagram of right end cover of actuator for the present application;

[0040] In the figure: 1-box, 2-crank, 3-guide slider, 4-driving pin, 5-guide through hole, 6-blind hole, 7-guide rod, 8-push rod, 9-inner piston cylinder, 10-outer piston cylinder, 11-right end cover, 12-left end cover, 13-push rod connecting plate, 14-push rod connecting cylinder, 15-inner piston, 16-spring, 17-outer piston ring, 18-oil inlet, 19-hydraulic oil cavity, 20-air inlet, 21-upper end cover bolt, 22-upper end cover spring gasket, 23-upper end cover, 24-left end cover bolt, 25-lower wear ring, 26-lower thrust bearing, 27-upper wear ring, 28-upper thrust bearing, 29-oil inlet, 30-oil inlet end cover, 31-oil inlet end cover bolt, 32-oil inlet end cover O-ring, 33-sleeve top sleeve, 34-sleeve joint, 35-spring guide plate one, 36-spring guide plate two, 37-push rod O-ring one, 38-push rod guide belt, 39-push rod O-ring two, 40-inner piston O-ring, 41-inner piston guide belt, 42-outer piston ring O-ring, 43-outer piston ring guide belt, 44-limiting screw, 45-fastening nut, 46-gasket, 47-plate screw, 48-driving pin cover plate, 49-limiting pile, 50-spring breathing hole. DETAILED DESCRIPTION

[0041] Embodiments of the present application are described in detail below with reference to the attached drawings, wherein like or similar elements are denoted by the same or similar reference signs throughout the drawings. The embodiments described below are exemplary, and are intended to explain the present application, and are not to be understood as limiting the present application.

[0042] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0043] In addition, the terms "first", "second", "third", etc. are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features referred to. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0044] As Figures 1-17As shown, the embodiment provides a double-piston pneumatic shift fork actuator based on hydraulic proportional transmission, which comprises a box body 1 and a cylinder cavity.

[0045] Specifically, the box body 1 is provided with a crank 2 for connecting an actuator, the crank 2 is provided with a guide sliding block 3 movable leftward and rightward, and a transmission pin 4 passes through the crank 2 and the guide sliding block 3 from top to bottom, and the transmission pin 4 is in clearance fit with the guide sliding block 3.

[0046] The guide sliding block 3 is further provided with a guide through hole 5 and a blind hole 6 in the leftward and rightward directions, respectively. Figure 6 As shown, a guide rod 7 passes through the guide through hole 5, and both ends of the guide rod 7 are welded to the inner wall of the box body; the guide rod 7 is in clearance fit with the guide sliding block 3, thereby providing a stable movement track for the guide sliding block 3.

[0047] A push rod 8 extends into the blind hole 6 and is connected with the guide sliding block 3. Figure 3b As shown, the blind hole 6 is provided with a sleeve top sleeve 33 near the bottom of the hole, and a sleeve joint 34 near the hole opening; the sleeve joint 34 is in threaded connection with the inner wall of the blind hole 6, and the left end of the push rod 8 passes through the sleeve joint 34 and is in threaded connection with the sleeve top sleeve 33.

[0048] The push rod 8 in the embodiment is connected with the guide sliding block 3 through the sleeve joint 34 and is limited by the sleeve top sleeve 33, thereby effectively improving the part connection under space limitation.

[0049] The cylinder cavity comprises an inner piston cylinder 9 and an outer piston cylinder 10, the right end of the outer piston cylinder 10 is welded to a right end cover 11, and the right end of the inner piston cylinder 9 is inserted into the inner wall of the right end cover 11; the left end of the inner piston cylinder 9 and the outer piston cylinder 10 are welded to a left end cover 12, and the left outer wall of the left end cover 12 is connected with the box body 1.

[0050] The push rod 8 passes through the box body 1 and the left end cover 12 to the right and is welded to a push rod connecting plate 13 inserted into the inner piston cylinder 9, the push rod connecting plate 13 is welded to a push rod connecting cylinder 14 on the right side, and the push rod connecting cylinder 14 is welded to an inner piston 15 assembled in the inner piston cylinder 9 on the right side.

[0051] The outer part of the inner piston cylinder 9 is provided with a spring 16, and an outer piston ring 17 is assembled between the right side of the spring 16 and the outer piston cylinder 10, and the left end cover 12 limits the spring 16 between the outer piston ring 17.

[0052] As shown in Figure 3 and Figure 15As shown, the inner piston cylinder 9 is provided with an array of oil ports 18 near the right end cover 11 side, the oil ports 18 communicate with the hydraulic oil cavity 19 in the inner and outer piston cylinder to realize the transmission of hydraulic medium; the box body 1 and the left end cover 12 are provided with a communicating air inlet 20.

[0053] In further embodiments, as shown in the figure, Figure 3 As shown, the upper part of the box body 1 is connected with the upper end cover 23 through the upper end cover bolt 21 and the upper end cover spring washer 22, and the right side wall of the box body 1 is connected with the left end cover 12 through the left end cover bolt 24.

[0054] As shown in the figure, Figure 4a , Figure 4b As shown, the lower end of the crank 2 is rotatably connected with the box body 1 through the lower wear ring 25 and the lower thrust bearing 26, and the upper end of the crank 2 is rotatably connected with the upper end cover 23 through the upper wear ring 27 and the upper thrust bearing 28.

[0055] In this embodiment, the lower wear ring 25 is gap-fitted with the crank 2 and the box body 1, the upper wear ring 27 is gap-fitted with the crank 2 and the upper end cover 23, the lower thrust bearing 26 is gap-fitted with the crank 2 to limit the downward movement of the crank, and the upper thrust bearing 28 is gap-fitted with the crank 2 to limit the upward movement of the crank.

[0056] In further embodiments, as shown in the figure, Figure 3 As shown, the right end of the inner piston cylinder 9 is inserted into the corresponding slot on the inner wall of the right end cover, and the right end of the inner piston cylinder 9 is gap-fitted with the slot on the inner wall of the right end cover.

[0057] In this embodiment, the center of the right end cover 11 is provided with an oil inlet 29, which is sealed by an oil inlet end cover 30. As shown in the figure, Figure 3d The oil inlet end cover 30 is connected with the right end cover 11 through the oil inlet end cover bolt 31 and sealed by the oil inlet end cover O-ring 32.

[0058] In further embodiments, as shown in the figure, Figure 3 As shown, the right inner wall of the left end cover 12 is welded with a spring guide plate one 35, and the left inner wall of the outer piston ring 17 is welded with a spring guide plate two 36, and the spring 16 is located between the spring guide plate one 35 and the spring guide plate two 36.

[0059] The spring guide plate one 35 and the spring guide plate two 36 can provide a stable motion trajectory for the spring 16, and assist in bearing and transmitting load to avoid the spring 16 from deviating or being damaged during work.

[0060] In further embodiments, as shown in the figure, Figure 3aAs shown, the left end cover 12 is provided with an end cover hole through which the push rod 8 passes, and a first O-ring groove, a guide belt groove and a second O-ring groove are sequentially provided on the hole wall of the end cover hole from left to right, the first O-ring groove is assembled with a push rod O-ring one 37, the guide belt groove is assembled with a push rod guide belt 38, and the second O-ring groove is assembled with a push rod O-ring two 39.

[0061] The outer wall of the push rod 8 is in contact with the push rod O-ring one 37, the push rod guide belt 38 and the push rod O-ring two 39. The push rod O-ring one 37 and the push rod O-ring two 39 play a sealing role when the air is ventilated, and the push rod guide belt 38 plays a guiding role when the push rod 8 moves.

[0062] Meanwhile, as shown in Figure 3c , the outer wall of the inner piston 15 is provided with an inner piston O-ring groove and an inner piston guide belt groove, the inner piston O-ring groove is assembled with an inner piston O-ring 40, and the inner piston guide belt groove is assembled with an inner piston guide belt 41; the inner and outer walls of the outer piston ring 17 are provided with an outer piston ring O-ring groove and an outer piston ring guide belt groove, the outer piston ring O-ring groove is assembled with an outer piston ring O-ring 42, and the outer piston ring guide belt groove is assembled with an outer piston ring guide belt 43.

[0063] The inner and outer walls of the inner piston cylinder 9 are in contact with the inner piston O-ring 40, the inner piston guide belt 41, the outer piston ring O-ring 42 and the outer piston ring guide belt 43, and the inner wall of the outer piston cylinder 10 is also in contact with the outer piston ring O-ring 42 and the outer piston ring guide belt 43.

[0064] In further embodiments, as shown in Figure 6 , Fig. 7, the box body 1 is threadedly connected with a limiting screw 44 for limiting the position of the crank, and two limiting screws 44 are provided in this embodiment to limit the rotation angle of the crank 2 on the left side and the right side. More specifically, the limiting screw 44 is connected to the box body 1 through a fastening nut 45 and a gasket 46.

[0065] In further embodiments, as shown in Figure 3 and Figures 9-11 , the outer surface of the transmission pin 4 is sprayed with wear-resistant material, and the upper end of the transmission pin 4 is thin and the lower end is thick, the upper end shoulder of the transmission pin 4 is clamped on the crank 2, and the lower end of the crank 2 is installed with a transmission pin cover plate 48 through a cover plate screw 47, and the transmission pin cover plate 48 limits the lower end of the transmission pin 4 to extend downward beyond the crank 2.

[0066] In further embodiments, as shown in Figure 17As shown, the inner wall of the right end cover 11 is provided with a limiting pile 49 extending to the left, and the pre-tightening force of the spring 16 can press the outer piston ring 17 against the limiting pile 49, so that the oil inlet 18 on the inner piston cylinder 9 can smoothly communicate with the hydraulic oil cavity 19 of the inner and outer piston cylinders, preventing the hydraulic oil from being difficult to enter the outer hydraulic oil cavity.

[0067] In further embodiments, as shown in Figure 1 As shown, the outer wall of the outer piston cylinder 10 is provided with a spring breathing hole 50 to prevent the spring from frequently moving and compressing the cavity gas to expand and pressure.

[0068] In this scheme, as shown in Figures 3 to 6 As shown, when the air is ventilated (i.e. the gas is introduced into the inner piston cylinder through the air inlet), the hydraulic oil is used as the force transmission medium (as shown in Figure 7a 、 7b The outer piston ring 17 is pushed by the inner piston 15 and the spring 16 is compressed (the push rod 8 drives the crank 2 to realize torque transmission, and the crank 2 is connected to the actuator), and the area difference between the outer piston ring 17 and the inner piston 15 is utilized, such as the inner piston area: outer piston ring area = 1:2, the inner piston stroke: outer piston ring stroke = 2:1, effectively shortening the spring compression stroke, and further shortening the spring free length and the overall length of the actuator.

[0069] The spring in the existing single-acting fork actuator is limited by the compression stroke, and can only be slender, such as the stroke of the push rod is 200mm, and the spring can only be compressed by 200mm; and since the compression stroke of the spring in this embodiment is reduced by a factor of two, a relatively short spring can be used, and the length is greatly shortened under the condition that the spring output force and torque remain unchanged.

[0070] In this scheme, the hydraulic proportional transmission based double-piston pneumatic fork actuator further nests the outer piston ring in the inner piston, and places the spring and the inner and outer pistons on the same side, further shortening the overall length of the actuator, improving the space utilization, and effectively reducing the use cost.

[0071] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0072] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the appended claims are intended to cover all such modifications that do not depart from the true spirit and scope of the application. Therefore, the application is not limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual-piston pneumatic shift fork actuator based on hydraulic proportional transmission, characterized in that, The device includes a housing and a cylinder chamber, the cylinder chamber being sealed and installed on the right side of the housing. A crank for connecting an actuator is installed inside the housing, and a guide slider is located in the middle of the crank. A transmission pin passes through the crank and the guide slider from top to bottom. The guide slider has guide through holes and blind holes on its left and right sides, respectively. A guide rod passes through the guide through holes, and both ends of the guide rod are fixed to the inner wall of the housing. The left end of a push rod extends into the blind hole and connects to the guide slider. The cylinder chamber includes an inner piston cylinder and an outer piston cylinder. The right end of the outer piston cylinder is fixed to a right end cap, and the right end of the inner piston cylinder is inserted into the inner wall of the right end cap. The inner piston cylinder and the left end of the outer piston cylinder are jointly fixed to the left end cover, and the housing is connected to the left outer wall of the left end cover; the push rod passes through the housing to the right, the left end cover extends into the inner piston cylinder and is fixed to the push rod connecting plate, the push rod connecting plate is fixed to the push rod connecting cylinder on the right side, and the push rod connecting cylinder is fixed to the inner piston assembled in the inner piston cylinder on the right side; a spring is fitted on the outside of the inner piston cylinder, and an outer piston ring is assembled between the inner and outer piston cylinders on the right side of the spring; an array of oil inlets is opened on the side of the inner piston cylinder near the right end cover, and the oil inlets are connected to the hydraulic oil chambers in the inner and outer piston cylinders; the housing and the left end cover are connected to the air inlet.

2. The dual-piston pneumatic shift fork actuator based on hydraulic proportional transmission according to claim 1, characterized in that, The upper part of the housing is connected to the upper end cover via upper end cover bolts and upper end cover spring washers. The right side wall of the housing is connected to the left end cover via left end cover bolts. The lower end of the crank is rotatably connected to the housing via a lower wear-resistant ring and a lower thrust bearing. The upper end of the crank is rotatably connected to the upper end cover via an upper wear-resistant ring and an upper thrust bearing.

3. The dual-piston pneumatic shift fork actuator based on hydraulic proportional transmission according to claim 1, characterized in that, The right end of the inner piston cylinder is inserted into the corresponding slot on the inner wall of the right end cover, and the right end of the inner piston cylinder is in clearance fit with the slot on the inner wall of the right end cover; and / or, an oil inlet is provided at the center of the right end cover, the oil inlet is sealed by an oil inlet end cover, the oil inlet end cover and the right end cover are connected by an oil inlet end cover bolt and sealed by an O-ring of the oil inlet end cover.

4. The dual-piston pneumatic shift fork actuator based on hydraulic proportional transmission according to claim 1, characterized in that, A ferrule top sleeve is provided near the bottom of the blind hole, and a ferrule connector is provided near the opening of the hole; the ferrule connector is threaded to the inner wall of the blind hole, and the left end of the push rod passes through the ferrule connector and is threaded to the ferrule top sleeve.

5. The dual-piston pneumatic shift fork actuator based on hydraulic proportional transmission according to claim 1, characterized in that, A spring guide plate 1 is fixedly connected to the right inner wall of the left end cap, and a spring guide plate 2 is fixedly connected to the left inner wall of the outer piston ring. The spring is located between the spring guide plate 1 and the spring guide plate 2.

6. The dual-piston pneumatic shift fork actuator based on hydraulic proportional transmission according to claim 1, characterized in that, The left end cap has an end cap hole for the push rod to pass through. From left to right, the end cap hole has a first O-ring groove, a guide strip groove, and a second O-ring groove. A push rod O-ring one is installed in the first O-ring groove, a push rod guide strip is installed in the guide strip groove, and a push rod O-ring two is installed in the second O-ring groove. The outer wall of the inner piston has an inner piston O-ring groove and an inner piston guide strip groove. An inner piston O-ring is installed in the inner piston O-ring groove, and an inner piston guide strip is installed in the inner piston guide strip groove. The inner and outer walls of the outer piston ring have outer piston ring O-ring grooves and outer piston ring guide strip grooves. An outer piston ring O-ring is installed in the outer piston ring O-ring groove, and an outer piston ring guide strip is installed in the outer piston ring guide strip groove.

7. The dual-piston pneumatic shift fork actuator based on hydraulic proportional transmission according to claim 1, characterized in that, The housing is threaded with a limiting screw that restricts the position of the crank.

8. The dual-piston pneumatic shift fork actuator based on hydraulic proportional transmission according to claim 1, characterized in that, The outer surface of the transmission pin is coated with a wear-resistant material, and the upper end of the transmission pin is thin and the lower end is thick. The upper shoulder of the transmission pin is stuck on the crank. The lower end of the crank is fitted with a transmission pin cover plate by cover plate screws. The transmission pin cover plate restricts the lower end of the transmission pin from extending downward out of the crank.

9. The dual-piston pneumatic shift fork actuator based on hydraulic proportional transmission according to claim 1, characterized in that, A limiting post extending to the left is provided on the inner wall of the right end cap, and the preload of the spring can press the outer piston ring tightly onto the limiting post.

10. The dual-piston pneumatic shift fork actuator based on hydraulic proportional transmission according to claim 1, characterized in that, A spring-loaded breathing hole is provided on the outer wall of the outer piston cylinder.

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