CN210800213U

CN210800213U - Straight-stroke pneumatic actuating mechanism

Info

Publication number: CN210800213U
Application number: CN201921917838.1U
Authority: CN
Inventors: 许晔; 王勇星; 张冠群
Original assignee: Wuxi Kelk Apparatus & Valve Co ltd
Current assignee: Wuxi Kelk Apparatus & Valve Co ltd
Priority date: 2019-11-08
Filing date: 2019-11-08
Publication date: 2020-06-19
Anticipated expiration: 2029-11-08

Abstract

The utility model provides a straight stroke pneumatic actuator, it can solve current straight stroke pneumatic actuator and very easily cause valve internals to damage because of the impact force is too big when driving valve and closing, shortens valve life's problem. The air cylinder comprises an air cylinder, a piston and a piston rod, wherein the left side and the right side of a lower air cylinder cover of the air cylinder are respectively provided with an exhaust channel, a buffering mechanism is arranged at an inlet of the exhaust channel, the buffering mechanism comprises a positioning support frame, a buffering stress rod and a spring, the positioning support frame is fixedly arranged on the top surface of the lower air cylinder cover and covers the inlet of the exhaust channel, the side wall of the positioning support frame is provided with an air vent, and the top surface is provided with a limiting hole; the spring is vertically arranged in a spring mounting groove of the exhaust channel; the upper end of buffering atress pole is stretched out by spacing hole, and lower extreme and spring butt still are equipped with on the buffering atress pole and are used for preventing it to continue to stretch out spacing portion in hole, along with buffering atress pole compression spring downwards, and the clearance between spacing portion and the entry of exhaust passage reduces gradually.

Description

Straight-stroke pneumatic actuating mechanism

Technical Field

The utility model relates to a pneumatic actuator field for the valve specifically is a straight stroke pneumatic actuator.

Background

For a large-caliber straight-stroke valve, the opening and closing of the large-caliber straight-stroke valve need to be driven by a straight-stroke pneumatic actuating mechanism. Fig. 1 shows a conventional straight-stroke pneumatic actuator, which mainly comprises a cylinder 1, a piston 2 and a piston rod 3, wherein the left side and the right side of an upper cylinder cover 4 of the cylinder 1 are respectively provided with an air inlet channel 5, and the left side and the right side of a lower cylinder cover 6 are respectively provided with an air outlet channel 7. In the closing process of the straight stroke valve, the pneumatic actuating mechanism is exhausted through the air inlet channel and the air exhaust channel, the piston moves downwards under the action of air pressure, and the piston rod is connected with the valve rod of the valve and moves downwards (in the direction of closing the valve), so that the valve is finally closed. However, because the output force of the actuating mechanism is large, in the process of quickly closing the valve, the valve rod connected with the piston rod pushes the valve core to impact the valve seat in a non-deceleration state, the impact force is large, the valve internals (particularly the valve core and the valve seat) of the valve are possibly damaged, and the service life of the valve is shortened.

Disclosure of Invention

To current straight stroke pneumatic actuator very easily cause valve internals to damage because of the impact force is too big when driving the valve and close, shorten valve life's technical problem, the utility model provides a straight stroke pneumatic actuator, it can effectively reduce the impact force that valve internals received when driving the valve and close, extension valve life.

The technical scheme is as follows: the utility model provides a straight stroke pneumatic actuator, its includes cylinder, piston and piston rod, the left and right sides of the lower cylinder cap of cylinder is equipped with exhaust passage, its characterized in that respectively: the inlet of the exhaust passage is also provided with a buffer mechanism, the buffer mechanism comprises a positioning support frame, a buffer stress rod and a spring, the positioning support frame is fixedly arranged on the top surface of the lower cylinder cover and covers the inlet of the exhaust passage, the side wall of the positioning support frame is provided with a vent hole, and the top surface is provided with a limiting hole; a spring mounting groove is formed in the inner wall of the lower end of the exhaust channel, and the spring is vertically mounted in the spring mounting groove; the upper end of buffering atress pole by spacing hole stretches out, the lower extreme with the upper end butt of spring, still be equipped with on the buffering atress pole and be used for preventing it to continue to stretch out spacing portion in spacing hole, and along with buffering atress pole compresses downwards the spring, spacing portion with clearance between exhaust passage's the entry reduces gradually.

It is further characterized in that:

the two buffer mechanisms are symmetrically arranged on the piston rod.

The positioning support frame is fixedly installed on the top surface of the lower cylinder cover through screws, and the vent holes are circumferentially and uniformly distributed on the side wall of the positioning support frame.

The limiting hole, the inlet of the exhaust channel and the spring mounting groove are coaxially arranged.

Buffering atress pole includes the thick round bar in upper portion and the thin round bar in lower part of coaxial setting, spacing portion sets up on the thick round bar in upper portion, the upper end of the thick round bar in upper portion by spacing hole cooperation is stretched out, the thin round bar in lower part inserts inside just the lower terminal surface of the thick round bar in upper portion with the upper end butt of spring.

The limiting part is of a bowl-shaped structure or an inverted frustum structure and is coaxially arranged with the buffering stress rod, and the diameter of the upper end of the limiting part is larger than that of the limiting hole and smaller than that of the inlet of the exhaust channel; when the spring is in a natural state, the upper end face of the limiting portion abuts against the top face of the positioning support frame, and when the spring is in a compressed state, the limiting portion extends into the inlet of the exhaust passage.

When the spring is in a completely compressed state, the top surface of the limiting part is flush with the top surface of the lower cylinder cover.

The utility model has the advantages that:

the utility model discloses a pneumatic actuator, buffer gear has been add to its entrance at exhaust passage, continuous downstream along with the piston, the valve is closed gradually, when the piston motion contacts with buffering atress pole, buffer gear begins to play the cushioning effect promptly, specifically do, continue to descend along with the piston, buffering atress pole compression spring downwards, make the clearance between spacing portion and exhaust passage's the entry reduce gradually, the pipeline sectional area that the air current passes through is continuous reducing promptly, the continuous reduction of gas flow that passes through in the unit interval, thereby exhaust velocity is more and more slow, the resistance that the piston received is more and more big, make the piston can be steady arrive terminal position, thereby guarantee that valve door internals no longer receives strong impact, extension valve life.

Drawings

FIG. 1 is a front cross-sectional view of a conventional straight-stroke pneumatic actuator;

fig. 2 is a main sectional view of the present invention with the valve in an open state;

FIG. 3 is an enlarged view of area A of FIG. 2;

FIG. 4 is a schematic view of the buffer mechanism in the buffering process;

FIG. 5 is a schematic view of the buffer mechanism at the end of buffering;

FIG. 6 is a front view of the buffering stress rod when the limiting part is in a bowl-shaped structure;

fig. 7 is a front view of the buffering stress rod when the limiting part is in an inverted frustum structure.

Reference numerals: 1-a cylinder; 2-a piston; 3-a piston rod; 4, mounting a cylinder cover; 5-an air intake passage; 6-lower cylinder cover; 7-an exhaust channel; 8-a buffer mechanism; 9-positioning a support frame; 10-a buffer stress bar; 11-a spring; 12-a screw; 13-a vent hole; 14-spring mounting groove; 15-a limiting part; 16-upper round bar; 17-lower thin round bar.

Detailed Description

Referring to fig. 2 to 7, the utility model discloses a straight stroke pneumatic actuator, it includes cylinder 1, piston 2 and piston rod 3, the left and right sides of the lower cylinder cap 6 of cylinder 1 is equipped with exhaust passage 7 respectively, buffer gear 8 is still installed at the entrance of exhaust passage 7, buffer gear 8 includes positioning support frame 9, buffering atress pole 10 and spring 11, positioning support frame 9 is fixed mounting on the top surface of lower cylinder cap 6 and covers the entrance of exhaust passage 7 through screw 12, air vent 13 has been evenly distributed along its circumference on the lateral wall of positioning support frame 9, air vent 13 can guarantee that the air current smoothly gets into exhaust passage and then discharges actuating mechanism, it has spacing hole to open on the top surface of positioning support frame 9; a spring mounting groove 14 is formed in the inner wall of the lower end of the exhaust channel 7, the limiting hole, the inlet of the exhaust channel 7 and the spring mounting groove 14 are coaxially arranged, and the spring 11 is vertically mounted in the spring mounting groove 14; the upper end of buffering atress pole 10 is stretched out by spacing hole, and the upper end butt of lower extreme and spring 11 still is equipped with on the buffering atress pole 10 and is used for preventing it to continue upwards to stretch out spacing portion 15 in hole, and along with buffering atress pole 10 downward compression spring 11, the clearance between spacing portion 15 and exhaust passage 7's the entry reduces gradually.

Two damping mechanisms 8 are arranged symmetrically with respect to the piston rod 3, see fig. 2. By the design, the left and right stress of the piston contacting the two buffer mechanisms can be ensured to be uniform, and unilateral force is not generated, so that the actuator is prevented from being damaged.

Referring to fig. 3 and 6, the buffering stress rod 10 includes an upper thick round rod 16 and a lower thin round rod 17 which are coaxially arranged, the limiting portion 15 is arranged on the upper thick round rod 16, the upper end of the upper thick round rod 16 is matched with and extends out of the limiting hole, the lower thin round rod 17 is inserted into the spring 11, and the lower end surface of the upper thick round rod 16 is abutted to the upper end of the spring 11. So design, buffering atress pole simple structure, the manufacturing of being convenient for, the thin round pole of lower part inserts the inside and thick round pole's in upper portion lower terminal surface and the upper end butt of spring, can make the structure more stable, and the atress is even when the spring pressurized.

Referring to fig. 3 to 7, the limiting portion 15 is in a bowl-shaped structure or an inverted frustum structure and is coaxially arranged with the buffering stress rod 10, and the diameter of the upper end of the limiting portion 15 is larger than the diameter of the limiting hole and smaller than the diameter of the inlet of the exhaust channel 7; when the spring 11 is in a natural state, the upper end surface of the limiting part 15 abuts against the top surface of the positioning support frame 9, as shown in fig. 3; when the spring 11 is in a compressed state, the limiting part 15 extends into the inlet of the exhaust channel 7, as shown in fig. 4; when the spring 11 is in the fully compressed state, the top surface of the stopper portion 15 is flush with the top surface of the lower cylinder head 6, as shown in fig. 5. So design, the simple structure of spacing portion, the processing of being convenient for along with spacing portion stretches into exhaust passage's entry, can make the continuous reduction of pipeline sectional area that the air current passes through, reaches the buffering effect.

The following detailed description discloses a pneumatic actuator's buffer process: referring to fig. 3 to 5, in fig. 3, the piston 2 is not yet in contact with the buffering force-bearing rod 10, the buffering mechanism 8 does not work, the effective radius at the inlet of the exhaust passage 7 is L1, as the piston 2 moves downwards, the piston 2 starts to press the buffering force-bearing rod 10 downwards, the limiting part 15 gradually extends into the inlet of the exhaust passage 7, as shown in fig. 4, the effective radius at the inlet of the exhaust passage 7 is L2, as the piston 2 descends to the lowest position, as shown in fig. 5, the limiting part 15 completely extends into the inlet of the exhaust passage 7, as the effective radius at the inlet of the exhaust passage 7 is L3, as the limiting part 15 is in a bowl-shaped structure or an inverted frustum-shaped structure, there are L1 > L2 > L3, that as the piston 2 descends, the pipe cross-section area at the inlet of the exhaust passage 7 is continuously reduced, so that the gas flow passing through the unit time is continuously reduced, and the exhaust speed, the piston is subjected to increasingly larger resistance, so that the piston can reach the end position smoothly. The state of fig. 5 is an extreme state, and during normal valve closure, the valve spool valve seats are in contact before this state is reached, so the fig. 5 position cannot be reached.

Claims

1. The utility model provides a straight stroke pneumatic actuator, its includes cylinder, piston and piston rod, the left and right sides of the lower cylinder cap of cylinder is equipped with exhaust passage, its characterized in that respectively: the inlet of the exhaust passage is also provided with a buffer mechanism, the buffer mechanism comprises a positioning support frame, a buffer stress rod and a spring, the positioning support frame is fixedly arranged on the top surface of the lower cylinder cover and covers the inlet of the exhaust passage, the side wall of the positioning support frame is provided with a vent hole, and the top surface is provided with a limiting hole; a spring mounting groove is formed in the inner wall of the lower end of the exhaust channel, and the spring is vertically mounted in the spring mounting groove; the upper end of buffering atress pole by spacing hole stretches out, the lower extreme with the upper end butt of spring, still be equipped with on the buffering atress pole and be used for preventing it to continue to stretch out spacing portion in spacing hole, and along with buffering atress pole compresses downwards the spring, spacing portion with clearance between exhaust passage's the entry reduces gradually.

2. A straight-stroke pneumatic actuator as claimed in claim 1, wherein: the two buffer mechanisms are symmetrically arranged on the piston rod.

3. A straight-stroke pneumatic actuator as claimed in claim 1 or 2, wherein: the positioning support frame is fixedly installed on the top surface of the lower cylinder cover through screws, and the vent holes are circumferentially and uniformly distributed on the side wall of the positioning support frame.

4. A straight-stroke pneumatic actuator as claimed in claim 1 or 2, wherein: the limiting hole, the inlet of the exhaust channel and the spring mounting groove are coaxially arranged.

5. A straight-stroke pneumatic actuator as claimed in claim 1 or 2, wherein: buffering atress pole includes the thick round bar in upper portion and the thin round bar in lower part of coaxial setting, spacing portion sets up on the thick round bar in upper portion, the upper end of the thick round bar in upper portion by spacing hole cooperation is stretched out, the thin round bar in lower part inserts inside just the lower terminal surface of the thick round bar in upper portion with the upper end butt of spring.

6. A straight-stroke pneumatic actuator as claimed in claim 5, wherein: the limiting part is of a bowl-shaped structure or an inverted frustum structure and is coaxially arranged with the buffering stress rod, and the diameter of the upper end of the limiting part is larger than that of the limiting hole and smaller than that of the inlet of the exhaust channel; when the spring is in a natural state, the upper end face of the limiting portion abuts against the top face of the positioning support frame, and when the spring is in a compressed state, the limiting portion extends into the inlet of the exhaust passage.

7. A straight-stroke pneumatic actuator as claimed in claim 6, wherein: when the spring is in a completely compressed state, the top surface of the limiting part is flush with the top surface of the lower cylinder cover.