阅读说明：本技术 摆臂式阀门限位开关 (Swing arm type valve limit switch ) 是由 钟盛辉 蒋晓红 蹇开任 罗冠华 王从令 张云福 杨建松 于 2021-01-25 设计创作，主要内容包括：本发明提供一种摆臂式阀门限位开关,包括支撑主体、微动开关、杠杆、滚轮和转轴,杠杆可转动地安装在支撑主体上,杠杆的头部用于触发微动开关,杠杆的尾部安装有滚轮,所述转轴上开设有与滚轮配合的凹槽,常态时,滚轮部分地卡入所述凹槽中,当转轴转动时,转轴使滚轮产生偏移并带动杠杆转动,杠杆的头部触发微动开关；第一弹性复位元件,对杠杆施加弹力,常态时,使滚轮保持在凹槽内,并在杠杆触发微动开关后带动杠杆复位,第二弹性复位元件,设置在转轴与支撑主体之间,用于转轴复位。本发明由于采用转轴、滚轮、杠杆的组合结构进行触发,使用单一路径信号传递,开关通过杠杆直接触发,反应迅速并且可靠。(The invention provides a swing arm type valve limit switch, which comprises a support main body, a microswitch, a lever, a roller and a rotating shaft, wherein the lever is rotatably arranged on the support main body, the head part of the lever is used for triggering the microswitch, the tail part of the lever is provided with the roller, the rotating shaft is provided with a groove matched with the roller, the roller is partially clamped into the groove in a normal state, when the rotating shaft rotates, the rotating shaft enables the roller to generate deviation and drives the lever to rotate, and the head part of the lever triggers the microswitch; the first elastic reset element applies elasticity to the lever, the roller is kept in the groove in a normal state, the lever is driven to reset after the lever triggers the microswitch, and the second elastic reset element is arranged between the rotating shaft and the supporting main body and used for resetting the rotating shaft. The invention uses the combination structure of the rotating shaft, the roller and the lever to trigger, uses single path signal transmission, and the switch is directly triggered by the lever, thus the reaction is rapid and reliable.)

1. The utility model provides a swing arm formula valve limit switch which characterized in that: comprises a supporting main body, a microswitch arranged on the supporting main body and a control unit,

a lever rotatably mounted on the support body about an axis, a head of the lever being for activating the microswitch;

the roller can be rotatably arranged at the tail part of the lever along the axis of the roller and can rotate along with the lever;

a rotating shaft rotatably mounted on the support body along its axis for transmitting a driving force from an actuator to a lever; the microswitch and the rotating shaft are respectively positioned at two sides of the rotating center of the lever, the rotating shaft is parallel to the axis of the roller, the rotating shaft is provided with a groove matched with the roller, the roller is partially clamped in the groove in a normal state, when the rotating shaft rotates, the rotating shaft enables the roller to deviate and drives the lever to rotate, and the head of the lever triggers the microswitch;

the first elastic reset element is arranged on the support main body and applies elasticity to the lever, the roller is kept in the groove in a normal state, and the lever is driven to reset after the lever triggers the microswitch,

and the second elastic reset element is arranged between the rotating shaft and the supporting main body and used for resetting the rotating shaft.

2. The rocker arm valve limit switch of claim 1, wherein: the groove is an arc-shaped groove which is symmetrical about the axis of the roller, and the lever can be rotated to trigger the microswitch by the forward rotation or the reverse rotation of the rotating shaft.

3. The rocker arm valve limit switch of claim 1, wherein: the supporting body comprises a supporting seat and a shell covering the supporting seat, the lever and the microswitch are arranged on the supporting seat, the rotating shaft is arranged on the shell through a shaft sleeve, the inner section of the rotating shaft is located in the shell, and the outer section of the rotating shaft penetrates out of the shell and is connected with a stirring piece used for transmitting torque force.

4. The rocker arm valve limit switch of claim 3, wherein: the supporting seat is provided with a mounting hole, the first elastic reset element is a spring arranged in the mounting hole, two ends of the spring are respectively abutted against the supporting seat and the tail of the lever, and the spring and the rotating shaft are respectively positioned on two opposite sides of the tail of the lever.

5. The rocker arm valve limit switch of claim 3, wherein: the support seat is provided with a limiting part used for limiting the pressing range of the lever when the lever presses the microswitch, the first elastic reset element enables the lever to be kept in a state of pressing the microswitch in a normal state, and when the rotating shaft drives the lever to rotate, the lever releases the microswitch.

6. The rocker arm valve limit switch of claim 3, wherein: the poking piece is sleeved outside the rotating shaft, the circumferential relative position between the poking piece and the rotating shaft is adjustable, and the poking piece and the rotating shaft are locked through the locking assembly to transmit torque.

7. The rocker arm valve limit switch of claim 3, wherein: the second elastic reset element is a torsion spring, the torsion spring is sleeved on the outer section of the rotating shaft, a fixed disc is arranged on the outer section of the rotating shaft, a limiting rod is arranged on the fixed disc, a limiting block is arranged on the outer wall of the shell, one end of the torsion spring abuts against the limiting rod, and the other end of the torsion spring abuts against the limiting block.

8. The rocker arm valve limit switch of claim 3, wherein: the connecting part is used for installation and is arranged on the outer walls of at least two sides of the shell, and the connecting part is a blind hole with internal threads or a connecting seat with an installation hole.

9. The rocker arm valve limit switch of claim 1, wherein: the rotation axis of pivot is parallel with the rotation axis of lever, the afterbody of lever is provided with two ear seats, the gyro wheel is installed between two ear seats through first round pin axle.

10. The rocker arm valve limit switch of claim 1, wherein: the width of the groove along the axial direction of the rotating shaft is larger than that of the roller.

11. The rocker arm valve limit switch of claim 1, wherein: the roller is made of hardened alloy steel, and the surface of the roller is coated with a wear-resistant coating.

12. The rocker arm valve limit switch of claim 1, wherein: the shell of the microswitch is made of ceramic materials.

13. The rocker arm valve limit switch of claim 12, wherein: the housing includes an upper cover and a base that are riveted together.

14. The rocker arm valve limit switch of claim 3, wherein: the shell and the supporting seat are sealed through a sealing ring, and the sealing ring is made of ethylene propylene diene monomer; the back of the supporting seat is provided with a cable channel, a cable is connected into the cable channel and connected with the microswitch, and the cable channel is sealed through high-temperature-resistant epoxy resin.

Technical Field

The invention belongs to the technical field of valves, and particularly relates to a swing arm type valve limit switch.

Background

With the development of industry, the working conditions of the existing valves are continuously changed, and the requirements of industries such as petroleum, petrochemical industry, metallurgy, power stations and the like on the limit switches of the valves of the accessories matched with the valves are gradually improved. The switch is at a high temperature for a long time and mechanical wear occurs at a high frequency. The economic loss caused by the fact that the accessories are replaced when the machine is stopped under the working conditions of a power station and the like is huge, and the service life of the valve limit switch is more strictly required.

The existing limit switch of the straight stroke valve generally adopts a swing rod part to be matched with two trigger rod parts with reset springs, an actuating mechanism drives a swing arm to rotate, the swing rod deflects, pressure is provided for a trigger rod at one side to trigger a microswitch at the side, and a position signal of the current valve is output. The rocker and the trigger rod are adopted for triggering, on one hand, certain hysteresis exists during triggering, namely the actuating mechanism is in contact with the rocker, but a certain time is still needed for transmitting the actuating mechanism to the microswitch, and the required effect is achieved by adjusting the mounting position of the switch in a more complicated way; on the other hand, because two independent trigger rods are used, failure probability exists in each trigger action, the condition that the whole valve limit switch fails due to single-side failure easily occurs, and the reliability of the trigger structure is greatly reduced.

Disclosure of Invention

In view of the above-mentioned deficiencies of the prior art, the present invention provides a swing arm type valve limit switch, which improves the reliability of the limit switch triggering.

In order to achieve the above objects and other related objects, the technical solution of the present invention is as follows:

a swing arm type valve limit switch, which comprises a support main body, a micro switch arranged on the support main body and a valve body,

a lever rotatably mounted on the support body about an axis, a head of the lever being for activating the microswitch;

the roller can be rotatably arranged at the tail part of the lever along the axis of the roller and can rotate along with the lever;

a rotating shaft rotatably mounted on the support body along its axis for transmitting a driving force from an actuator to a lever; the microswitch and the rotating shaft are respectively positioned at two sides of the rotating center of the lever, the rotating shaft is parallel to the axis of the roller, the rotating shaft is provided with a groove matched with the roller, the roller is partially clamped in the groove in a normal state, when the rotating shaft rotates, the rotating shaft enables the roller to deviate and drives the lever to rotate, and the head of the lever triggers the microswitch;

the first elastic reset element is arranged on the support main body and applies elasticity to the lever, the roller is kept in the groove in a normal state, and the lever is driven to reset after the lever triggers the microswitch,

and the second elastic reset element is arranged between the rotating shaft and the supporting main body and used for resetting the rotating shaft.

Optionally, the groove is an arc-shaped groove symmetrical about the axis of the roller, and the lever can be triggered by the rotation of the lever through the forward rotation or the reverse rotation of the rotating shaft.

Optionally, the support main body comprises a support seat and a shell covering the support seat, the lever and the microswitch are arranged on the support seat, the rotating shaft is mounted on the shell through a shaft sleeve, the inner section of the rotating shaft is located in the shell, and the outer section of the rotating shaft penetrates out of the shell and is connected with a stirring piece for transmitting torque force.

Optionally, the supporting seat is provided with a mounting hole, the first elastic reset element is a spring arranged in the mounting hole, two ends of the spring respectively abut against the supporting seat and the tail of the lever, and the spring and the rotating shaft are respectively located on two opposite sides of the tail of the lever.

Optionally, the support seat is provided with a limiting portion for limiting a pressing range of the lever when the lever presses the microswitch, the first elastic reset element keeps the lever in a state of pressing the microswitch in a normal state, and when the rotating shaft drives the lever to rotate, the lever releases the microswitch.

Optionally, the toggle member is sleeved outside the rotating shaft, the circumferential relative position between the toggle member and the rotating shaft is adjustable, and the toggle member and the rotating shaft are locked by the locking assembly to transmit torque.

Optionally, the second elastic reset element is a torsion spring, the torsion spring is sleeved on the outer section of the rotating shaft, a fixed disc is arranged on the outer section of the rotating shaft, a limiting rod is arranged on the fixed disc, a limiting block is arranged on the outer wall of the shell, one end of the torsion spring abuts against the limiting rod, and the other end of the torsion spring abuts against the limiting block.

Optionally, the outer walls of at least two sides of the housing are provided with connecting parts for installation, and the connecting parts are blind holes with internal threads or connecting seats with installation holes.

Optionally, the rotation axis of pivot is parallel with the rotation axis of lever, the afterbody of lever is provided with two ear seats, the gyro wheel is installed between two ear seats through first round pin axle.

Optionally, the width of the groove along the axial direction of the rotating shaft is larger than that of the roller.

Optionally, the roller is made of hardened alloy steel, and the surface of the roller is coated with a wear resistant coating.

Optionally, the housing of the microswitch is made of a ceramic material.

Optionally, the housing comprises an upper cover and a base riveted together.

Optionally, the shell and the supporting seat are sealed by a sealing ring, and the sealing ring is made of ethylene propylene diene monomer; the back of the supporting seat is provided with a cable channel, the cable is connected with the microswitch through the cable channel, and the cable channel is sealed through high-temperature-resistant epoxy resin.

As described above, the present invention has the following advantageous effects: according to the invention, when the rotating shaft is driven to rotate, the roller is extruded by the rotating shaft to generate deviation and exit from the groove, the roller deviates to drive the lever to rotate, and the matching state of the head of the lever and the microswitch is changed, so that the microswitch is triggered; when the torsion on the rotating shaft is removed, the second elastic element enables the rotating shaft to reset and rotate to the position where the groove is opposite to the roller; the first elastic reset element resets the lever, and the roller returns to and is kept in the groove again under the action of the elastic force applied to the lever to wait for the next triggering action; the structure adopts the combined structure of the rotating shaft, the roller and the lever to trigger, single-path signal transmission is adopted, the switch is directly triggered through the lever, and the response is rapid and reliable. And because the tail part of the lever is provided with the roller to be matched with the rotating shaft, the abrasion is reduced by rolling friction, and the service life is prolonged.

Drawings

FIG. 1 is a cross-sectional view of one embodiment of the present invention;

FIG. 2 is an enlarged view of a portion of FIG. 1;

FIG. 3 is a view A-A of FIG. 1;

FIG. 4 is a perspective view of the internal structure of one embodiment of the present invention;

FIG. 5 is a schematic view of another angle in FIG. 4;

FIG. 6 is a perspective view of the external structure of one embodiment of the present invention;

FIG. 7 is a front view of one embodiment of the present invention;

FIG. 8 is a left side view of FIG. 7;

fig. 9 is an exploded view of the microswitch.

Part number description:

1-a support body; 11-a housing; 12-a support base; 13-a connecting part; 14-mounting holes; 15-sealing ring; 16-a limiting block; 17-a seal groove; 18-a support; 2-a rotating shaft; 21-a groove; 22-fixed disk; 23-a limiting rod; 3-a lever; 31-ear mount; 32-a first pin; 33-a circular truncated cone; 34-a second pin; 4-a roller; 5-a microswitch; 51-an upper cover; 52-a base; 53-contacts; 54-contact piece; 6-a toggle piece; 71-a spring; 72-torsion spring; 73-lock washer; 74-a nut; 81-a first copper sleeve; 82-a second copper sleeve; 83-a retainer ring for a shaft; 84-a gasket; 85-pressing plate; 86-O-shaped ring; 87-screws; 88-a wear-resistant washer; 91-a cable; 92-briquetting; 93-epoxy resin.

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

Examples

As shown in fig. 1 to 5, the swing arm type valve limit switch in this example includes a support main body 1, a micro switch 5, a lever 3 (or a swing arm), a rotating shaft 2, a roller 4, a first elastic reset element and a second elastic reset element;

the supporting body 1 is a body for mounting and supporting various parts; the middle part of the lever 3 can be rotatably arranged on the supporting main body 1 around an axis, the head part (or the first end) of the lever 3 is used for triggering the micro switch 5, and the roller 4 is arranged at the tail part (the second end) of the lever 3; the roller 4 can be rotatably arranged at the tail part of the lever 3 along the axis of the roller and can rotate along with the swinging of the lever 3;

the rotating shaft 2 is rotatably arranged on the supporting main body 1 along the axis of the rotating shaft, and is used for transmitting driving force from an actuating mechanism to the lever 3 so as to drive the lever 3 to act; the rotating shaft 2 is directly or indirectly connected with the actuating mechanism so that the rotating shaft 2 rotates along with the position change of the valve, the micro switch 5 and the rotating shaft 2 are respectively positioned at two sides of the rotating center of the lever 3, namely the micro switch 5 is close to the head of the lever 3, and the rotating shaft 2 is close to the tail of the lever 3; the axis of the rotating shaft 2 is parallel to the axis of the roller 4, a groove 21 matched with the roller 4 is formed in the outer wall of the rotating shaft 2, the roller 4 is partially clamped in the groove 21 in a normal state, and when the rotating shaft 2 rotates, the rotating shaft 2 enables the roller 4 to exit from the groove 21 and generate offset, so that the lever 3 is driven to rotate, and the head of the lever 3 triggers the microswitch 5;

the first elastic reset element is arranged on the support main body 1, applies elastic force to the lever 3, keeps the roller 4 in the groove 21 in a normal state, and drives the lever 3 to reset after the lever 3 triggers the microswitch 5 (namely after the external force is removed), wherein the first elastic reset element adopts a spring 71.

And the second elastic reset element is arranged between the rotating shaft 2 and the supporting main body 1, and after the torsion of the actuating mechanism on the rotating shaft 2 is removed, the rotating shaft 2 is reset to the position where the groove 21 is matched with the roller 4 through the second elastic element, wherein the second elastic reset element adopts a torsion spring 72 in the example.

In the structure, when the rotating shaft 2 is driven to rotate, the roller 4 is extruded by the rotating shaft 2 to generate deviation to exit from the groove 21, the roller 4 deviates to drive the lever 3 to rotate, and the matching state of the head of the lever 3 and the microswitch 5 is changed, so that the microswitch 5 is triggered; when the torsion on the rotating shaft 2 is removed, the second elastic element enables the rotating shaft 2 to reset and rotate to the position where the groove 21 is opposite to the roller 4; the first elastic reset element resets the lever 3, and the roller 4 is returned to and kept in the groove 21 again by the elastic action exerted on the lever 3 to wait for the next trigger action; the structure adopts the combined structure of the rotating shaft 2, the roller 4 and the lever 3 for triggering, single-path signal transmission is used, the switch is directly triggered through the lever 3, and the response is rapid and reliable. And because the tail part of the lever 3 is provided with the roller 4 to be matched with the rotating shaft 2, the abrasion is reduced by rolling friction, and the service life is prolonged.

The micro switch 5 can be triggered in a normally closed mode or a normally open mode, and only state change is needed. As shown in fig. 2, the present embodiment adopts a normally closed mode, that is, the head of the lever 3 presses the contact 53 of the microswitch 5 in a normal state; the valve actuating mechanism enables the rotating shaft 2 to rotate, the roller 4 is in contact with the groove 21, the rotating shaft 2 rotates to drive the roller 4 to deflect, the lever 3 tilts after the spring 71 is compressed, the contact 53 of the microswitch 5 is released, and a digital signal of the current valve position is output. Before the rotating shaft 2 drives the switch to act, the lever 3 is under the force of the spring 71 and is in a horizontal position, the contact 53 of the micro switch 5 is compressed, the micro switch 5 is in an NC state, and after the lever 3 tilts up, the micro switch 5 is switched to an NO state to indicate that the current valve position is changed. In other embodiments, the lever 3 is not in contact with the microswitch 5 in a normal state, and the rotating shaft 2 drives the lever 3 to compress the microswitch 5 when rotating, so that triggering is realized.

As shown in fig. 2, the groove 21 is an arc-shaped groove which is symmetrical with respect to the axis of the roller 4, that is, the groove 21 is arc-shaped when viewed along the axial direction of the rotating shaft 2, and the arc-shaped groove is matched with the roller 4 to realize bidirectional matching, that is, the rotating shaft 2 rotates clockwise or counterclockwise, and both can be triggered to realize functions. The arc radius of the arc groove can be slightly larger than or equal to the radius of the roller 4; in other embodiments, the projection of the groove 21 in the axial direction of the rotating shaft 2 may also be a sector or an isosceles trapezoid, so long as the left and right sides of the groove 21 are symmetrical with respect to the roller 4 in the figure, a two-phase triggering can be achieved.

As shown in fig. 1, in this embodiment, the supporting body 1 includes a supporting seat 12 and a housing 11 covering the supporting seat 12, wherein the supporting seat 11 includes an integrated bottom plate and a seat body located in the middle of the bottom plate, the lever 3 and the micro switch 5 are disposed on the supporting seat 12 and covered by the housing 11, the rotating shaft 2 is mounted on the housing 11 through a shaft sleeve (copper sleeve), an inner section of the rotating shaft 2 is located in the housing 11, an inner end thereof is supported on an inner wall of the housing 11, and a first copper sleeve 81 is disposed between the inner wall of the housing 11 and the rotating shaft 2; the outer section of the rotating shaft 2 penetrates out of the shell 11 through a through hole formed in the shell 11 and is supported in the through hole through a second copper sleeve 82, and a sealing structure is arranged between the rotating shaft 2 and the through hole; the outer section of the rotating shaft 2 is connected with a stirring piece 6 used for transmitting torsion, and the stirring piece 6 is connected with an actuating mechanism to transmit the torsion, so that the rotating shaft 2 is driven to rotate.

As shown in fig. 2, the second copper bush 82 is in stepped fit with the inner wall of the via hole, and the inner end of the second copper bush 82 is axially positioned by a shaft retainer ring 83 arranged on the rotating shaft 2; the outer end of the second copper sleeve 82 is axially limited by a pressure plate 85, the pressure plate 85 is fixed on the shell 11 through a screw 87 and an elastic pad, a gasket 84 is arranged between the second copper sleeve 82 and the step of the inner wall of the through hole, and the gasket 84 can be made of graphite (namely a graphite gasket) to realize sealing; a copper wear-resistant gasket 88 is arranged between the shaft retainer ring 83 and the inner end of the second copper sleeve 82, and mainly used for wear resistance between the shaft retainer ring 83 and the shell 11. An O-shaped ring 86 is arranged between the rotating shaft 2 and the second copper sleeve 82 for sealing, the O-shaped ring 86 comprises a metal framework (such as stainless steel) and a sealing body (similar to the structure of an oil seal) coated on the periphery of the metal framework, and the sealing body is made of polytetrafluoroethylene so as to achieve the purposes of high temperature resistance and irradiation.

As shown in fig. 3, the rotating shaft 2 and the spring 71 are respectively located at two opposite sides of the tail of the lever 3, that is, in the figure, the rotating shaft 2 is located above the tail of the lever 3, the spring 71 is located below the tail of the lever 3, the support seat 12 is located below the tail of the lever 3, a mounting hole 14 is formed in the support seat, the spring 71 is arranged in the mounting hole 14, the upper end of the spring 71 abuts against the lower side of the tail of the lever 3, a round table 33 is arranged at the tail of the lever 3, the spring 71 is sleeved outside the round table 33 and is located with the spring 71, the lower end of the spring 71 abuts against the bottom of the mounting hole 14, in a normal state, the spring 71 lifts the tail of the lever 3, the head of the lever 3 is kept pressed on the contact 53 of.

In this example, the spring 71 is a compression spring, and because the spring 71 keeps the lever 3 in a state of pressing the contact 53 of the microswitch 5 in a normal state, when the rotating shaft 2 drives the lever 3 to rotate, the lever 3 releases the contact 53 of the microswitch 5; in order to limit the degree of pressing down of the head of the lever 3, the support base 12 is provided with a limit part, in this example, the limit part is the top of the support base 12, and when the lever 3 is in a horizontal position, the limit part is pressed on the top of the contact 53 and the support base 12 at the same time, so that the microswitch 5 is prevented from being crushed; the upper end of the supporting seat 12 is provided with an avoiding opening corresponding to the position of the tail part of the lever 3, so that the tail part can move downwards when the lever 3 tilts, and interference is avoided. In other embodiments, a tension spring may be provided to pull the head of the lever 3 downward.

The poking piece 6 is sleeved outside the rotating shaft 2, the circumferential relative position between the poking piece 6 and the rotating shaft 2 is adjustable, and the poking piece 6 and the rotating shaft 2 are locked through the locking assembly to transmit torque. Specifically, the fixed disc 22 is arranged at the outer section of the rotating shaft 2, the outer end of the rotating shaft 2 is provided with threads and is provided with a nut 74, and the toggle piece 6 is positioned between the nut 74 and the fixed disc 22 and is pressed tightly through the nut 74 and the anti-loose washer 73; therefore, the shifting piece 6 can synchronously rotate with the rotating shaft 2, and the combination of the nut 74 and the anti-loose washer 73 is adopted, so that the strength is ensured to be sufficient, and the anti-seismic performance of the structure is improved; the position of the poking part 6 relative to the circumferential direction of the rotating shaft 2 can be steplessly adjusted, and the structure can meet the requirements of different changed installation angles.

As shown in fig. 6 to 8, at least two outer walls of the housing 11 are provided with connecting portions 13 for installation, the connecting portions 13 are installation holes with internal threads, and the installation holes are blind holes to ensure the sealing performance of the housing 11; or the connecting seat is a connecting seat arranged on the outer wall of the shell 11, and a connecting hole is formed in the connecting seat. The stirring piece 6 can be circumferentially adjusted, and requirements of various installation angles can be met by combining the multidirectional installation holes in the shell 11, so that the problem of directivity of field installation is solved to a great extent, and the adaptability to field installation is improved.

The torsion spring 72 is sleeved on the outer section of the rotating shaft 2, the fixed disk 22 is provided with a limiting rod 23 towards the direction of the shell 11, the outer wall of the shell 11 is provided with a limiting block 16, one end of the torsion spring 72 abuts against the limiting rod 23, and the other end of the torsion spring abuts against the limiting block 16, so that the rotating shaft 2 is convenient to reset through torsion.

In this example, the lever 3 is mounted on the top of the supporting seat 12 through the second pin 34 and the support 18, the rotation axis of the rotating shaft 2 is parallel to the rotation axis of the lever 3, the two ear seats 31 are disposed at the tail of the lever 3, the roller 4 is mounted between the two ear seats 31 through the first pin 32, and the first pin 32, the second pin 34 and the rotating shaft 2 are parallel to each other.

As shown in FIG. 1, the width of the groove 21 along the axial direction of the rotating shaft 2 is greater than that of the roller 4, so that the structure can reduce the installation difficulty on one hand, facilitate the axial alignment of the groove 21 and the roller 4, and facilitate the processing on the other hand. The relative motion between the rotating shaft 2 and the roller 4 is accompanied by mechanical wear, under the application scene with high requirement on the electrical service life, in order to improve the wear resistance of the roller 4, the roller 4 is made of hardened alloy steel, the surface of the roller 4 is coated with a wear-resistant coating, the wear-resistant coating can be made of metal wear-resistant coatings, such as alloy coatings of nichrome, tungsten carbide and the like, and other wear-resistant coatings in the prior art can also be adopted.

At present, the valve limit switch in the market is limited by the materials of parts and components, and the performance of the valve limit switch in a severe environment is poor. For example, the sealing material is usually silicon rubber or nitrile rubber, which has excellent high and low temperature resistance, but is easily cracked and denatured when irradiated under the environment, resulting in sealing failure. The common material of the shell of the microswitch 5 component is general engineering plastic, so that the forming effect is good, the assembly is simple and convenient, but the general engineering plastic material is easy to deform under the environment with higher temperature requirement, the switch precision is influenced, and even the switch is directly failed. Therefore, in the embodiment, the housing of the microswitch 5 is made of ceramic materials, so that the defect that plastic materials are easy to age is overcome, the high temperature resistance and the irradiation resistance are realized, and the service life is greatly prolonged.

Referring to fig. 9, the housing includes an upper cover 51 and a base 52, the upper cover 51 and the base 52 are connected by riveting, and certainly, the housing further includes internal elements such as a spring plate, which are similar to the structure of the microswitch 5 of the plastic housing and are not described again.

Further, in order to enable the valve limit switch to adapt to high-temperature and irradiation environments, the shell 11 and the supporting seat 12 are sealed through a sealing ring 15, and the sealing ring 15 is made of ethylene propylene diene monomer; as shown in fig. 2 and 3, a sealing groove 17 is formed at the bottom of the supporting seat 12, the sealing ring 15 is installed in the sealing groove 17, and the lower end of the housing 11 is pressed against the sealing ring 15 and locked with the lower part of the supporting seat 11 by a fastening member; a cable channel for the cable 91 to penetrate is formed in the back of the supporting seat 12, the cable 91 is connected to the contact piece 54 of the microswitch 5 from the cable channel, and the cable channel is sealed by injecting high-temperature-resistant epoxy resin 93, wherein the high-temperature-resistant epoxy resin 93 in this example is high-temperature-resistant epoxy resin with a temperature of more than 200 degrees, and products of any company in the prior art can be adopted, such as epoxy resin sealant with a model of EPOCAP 16717A/B, single-component epoxy adhesive with a model of JL-6103, high-temperature-resistant epoxy resin structural adhesive with a model of DP8405NS, epoxy resin AB adhesive with a model of DP760, and the like; in other embodiments, the epoxy resin suitable for the corresponding temperature environment is selected according to the application environment of the switch. The cable 91 is also an irradiation-resistant cable (such as an irradiation-resistant low-smoke halogen-free flame-retardant cable), the cable 91 is pressed on the inner wall of the cable channel through the pressing block 92 after extending into the cable channel, and the end part of the cable is welded with the metal contact piece 54 of the microswitch 5; the glue-pouring sealing position is from the bottom end of the supporting seat 12 to the position of the metal contact piece 54, and the contact with the inside of the micro switch 5 is avoided.

The outer coating of switch signal line, polymer material commonly used, long-time the back of using, inevitably produces ageing phenomenon, and the sinle silk is easy to contact the short circuit this moment, not only influences switch life, the security performance of more direct relation equipment. In the embodiment, the cable part is encapsulated by high-temperature epoxy resin 93, so that secondary protection is provided, the service life of the valve is prolonged, the high-temperature epoxy resin 93 can work at 140 ℃ for a long time, and the reliability of the limit switch at high temperature is guaranteed.

In the prior art, the problem of failure caused by cracking and denaturation of a conventional sealing ring under irradiation, accelerated aging of a plastic shell of the microswitch 5 under high temperature and high irradiation and deformation failure are solved, accelerated aging is carried out under irradiation of a cable insulation coating layer, and the danger of wire core contact short circuit easily occurs. These factors all limit the application of the existing valve limit switch under high temperature and high radiation. The limit switch is sealed by the ethylene propylene diene monomer sealing ring, the ceramic microswitch 5 and the high-temperature epoxy resin 93, so that the limit switch has the use conditions under the severe requirements of high temperature, strong irradiation and the like.

The swing arm type valve limit switch disclosed by the invention uses the microswitch 5 with a ceramic shell, the shell 11 and the supporting seat 12 are sealed by an ethylene propylene diene monomer sealing ring, and a cable is sealed by high-temperature-resistant epoxy resin potting adhesive, so that the use reliability of the limit switch is ensured in a high-temperature and high-irradiation scene, and the service life of the valve limit switch is prolonged. The cable part uses high temperature epoxy 93 to glue and seals, and the performance obtains greatly improving in the aspect of the protection, has guaranteed limit switch's safety in utilization. In the prior art, the switch installation form is single, and the installation can not be carried out due to the sudden problem frequently encountered in field installation, and the adaptability of the field installation of the valve limit switch is greatly improved by the bidirectional trigger mechanism matched with the roller 4, the stepless adjusting mode of the stirring piece 6 and the multidirectional arrangement of the installation hole.

Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.