阅读说明：本技术 一体式先导压差控制自动往复气缸 (Integrated pilot pressure difference control automatic reciprocating cylinder ) 是由 张俊 王先艳 陶伟伟 卢文杰 曹永明 胡亮 于 2019-12-20 设计创作，主要内容包括：本发明涉及一种一体式先导压差控制自动往复气缸,包括：一气控阀模块、一气路连接板模块和一气缸模块,所述气控阀模块以螺杆连接所述气路连接板模块,所述气路连接板模块以螺杆连接所述气缸模块；其中,所述气缸模块包括气缸后盖部、缸体部和气缸前盖部,所述气缸后盖部开设一后盖气路和一后盖先导气路,所述气缸前盖部开设一前盖气路和一前盖先导气路,还包括两接触阀,两所述接触阀分别装配连接所述后盖先导气路和所述前盖先导气路。本申请气缸采用模块化设计思路,当气缸行程加长,只要加长气路连接板长度,当气缸使用形式改变时,只要气缸盖内的接触阀设计形式不改变,可以使用在任何气缸形式的改变,增加产品多样性。(The invention relates to an integrated pilot pressure difference control automatic reciprocating cylinder, which comprises: the pneumatic control valve module is connected with the pneumatic circuit connecting plate module through a screw rod, and the pneumatic circuit connecting plate module is connected with the air cylinder module through a screw rod; the cylinder module comprises a cylinder rear cover part, a cylinder body part and a cylinder front cover part, wherein the cylinder rear cover part is provided with a rear cover gas circuit and a rear cover pilot gas circuit, the cylinder front cover part is provided with a front cover gas circuit and a front cover pilot gas circuit, and the cylinder module further comprises two contact valves, and the contact valves are respectively in assembly connection with the rear cover pilot gas circuit and the front cover pilot gas circuit. This application cylinder adopts the modularized design thinking, when the cylinder stroke extension, as long as extension gas circuit connecting plate length, when the cylinder use form changes, as long as the contact valve design form in the cylinder head does not change, can use in the change of any cylinder form, increases product diversity.)

1. An integral pilot pressure differential control automatic reciprocating cylinder, comprising: the pneumatic control valve module is connected with the pneumatic circuit connecting plate module through a screw rod, and the pneumatic circuit connecting plate module is connected with the air cylinder module through a screw rod; wherein the content of the first and second substances,

the cylinder module comprises a cylinder rear cover part, a cylinder body part and a cylinder front cover part, wherein a rear cover gas circuit and a rear cover pilot gas circuit are arranged on the cylinder rear cover part, a front cover gas circuit and a front cover pilot gas circuit are arranged on the cylinder front cover part, and the cylinder module further comprises two contact valves which are respectively in assembly connection with the rear cover pilot gas circuit and the front cover pilot gas circuit.

2. The cylinder according to claim 1, wherein the contact valve is a two-position two-way valve, the contact valve includes a contact valve core, a contact spring, a contact bushing and a contact outer cover, the contact valve core is a rod body, a valve core air passage is formed in the rod body of the contact valve core, the contact valve core is connected with the contact bushing in a penetrating manner, the two contact outer covers are respectively inserted and connected with the rear cover pilot air passage and the front cover pilot air passage, the contact spring is inserted and connected with the contact valve core, and two ends of the contact spring are respectively connected with the contact outer cover and the contact valve core.

3. The cylinder as claimed in claim 2, further comprising a button valve, wherein the button valve is a two-position two-way valve, the button valve comprises a button outer cover, a button valve core, a button O-ring and a button spring, the button valve core is a rod body with a radially protruding front end, and the button outer cover is a hollow cylinder; the gas circuit connecting plate module comprises a gas circuit connecting plate, the gas circuit connecting plate is provided with a rear cover connecting gas circuit, a rear cover pilot connecting gas circuit, a front cover connecting gas circuit and a front cover pilot connecting gas circuit, the button valve is assembled and connected with the rear cover pilot connecting gas circuit, and the button spring, the button valve core, the button O-shaped ring and the button outer cover are sequentially put into and connected with the rear cover pilot connecting gas circuit.

4. The cylinder according to claim 3, further comprising two air resistors, wherein the air control valve module comprises an air control valve, the air control valve is a dual air control two-position five-way valve, the air control valve comprises a valve body, a rear air valve cavity and a front air valve cavity, the rear air valve cavity and the front air valve cavity are respectively connected with two sides of the valve body, an air inlet air passage of the valve body is respectively connected with the rear air valve pilot air passage and the front air valve pilot air passage, and the two air resistors are respectively connected with the rear air valve pilot air passage and the front air valve pilot air passage.

Technical Field

The invention relates to the technical field of cylinders, in particular to an integrated automatic reciprocating cylinder controlled by a pilot pressure difference.

Background

With the increasingly wide application of pneumatic systems in the field of automation, the control of conventional pneumatic actuators such as air cylinders is generally realized by electromagnetic valves (electromagnetic valves have the advantages of sensitive response and simple air path systems). However, in some special chemical industries, such as the industries where the filled liquid is flammable and explosive, the electromagnetic valve is not allowed to exist in the gas circuit control system due to potential safety hazards. The action execution of the air cylinder still adopts a mechanical type or an air control type.

Disclosure of Invention

In view of the above-mentioned drawbacks, the present invention provides an integrated pilot pressure difference controlled automatic reciprocating cylinder to solve the technical problems of the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

an integrated pilot pressure differential controlled automatic reciprocating cylinder comprising: the pneumatic control valve module is connected with the pneumatic circuit connecting plate module through a screw rod, and the pneumatic circuit connecting plate module is connected with the air cylinder module through a screw rod; the cylinder module comprises a cylinder rear cover part, a cylinder body part and a cylinder front cover part, wherein the cylinder rear cover part is provided with a rear cover gas circuit and a rear cover pilot gas circuit, the cylinder front cover part is provided with a front cover gas circuit and a front cover pilot gas circuit, and the cylinder module further comprises two contact valves, and the contact valves are respectively in assembly connection with the rear cover pilot gas circuit and the front cover pilot gas circuit.

According to the embodiment of the application cylinder, the contact valve is two-position two-way valve, the contact valve is including contact case, contact spring, contact bush and contact enclosing cover, the contact case is a body of rod, set up the case gas circuit in the body of rod of contact case, contact case through connection the contact bush, two the contact enclosing cover inserts respectively and connects back lid guide's gas circuit with protecgulum guide's gas circuit, the contact spring inserts and connects the contact case, the both ends of contact spring are connected respectively the contact enclosing cover with the contact case.

The cylinder according to the embodiment of the application further comprises a button valve, the button valve is a two-position two-way valve and comprises a button outer cover, a button valve core, a button O-shaped ring and a button spring, the button valve core is a rod body with a radially protruding front end, and the button outer cover is a hollow cylinder body; the gas circuit connecting plate module comprises a gas circuit connecting plate, the gas circuit connecting plate is provided with a rear cover connecting gas circuit, a rear cover pilot connecting gas circuit, a front cover connecting gas circuit and a front cover pilot connecting gas circuit, the button valve is assembled and connected with the rear cover pilot connecting gas circuit, and the button spring, the button valve core, the button O-shaped ring and the button outer cover are sequentially put into and connected with the rear cover pilot connecting gas circuit.

According to this application embodiment the cylinder, still include two air resistances, the air control valve module includes a gas control valve, the gas control valve is two-position five-way valve of two gas accuse, the gas control valve includes valve body, back air valve chamber and preceding air valve chamber are connected respectively the both sides of valve body, the air inlet gas circuit of valve body is connected with back air valve guide gas circuit and preceding air valve guide gas circuit respectively back air valve chamber and preceding air valve chamber, two the air resistance is connected respectively back air valve guide gas circuit and preceding air valve guide gas circuit.

This application improves current cylinder, when improving prior art reciprocating cylinder design shortcoming, for adapting to the many strokes that the cylinder used, the demand of many connected forms has provided the modularization design thinking, divides the integral type cylinder for gas accuse valve module, gas circuit connecting plate module and cylinder module (contain the pilot control).

Due to the adoption of the technical characteristics, compared with the prior art, the invention has the following advantages and positive effects:

firstly, the air cylinder adopts a modularized design idea of an air control valve module, an air path connecting plate module and an air cylinder module, when the stroke of the air cylinder is lengthened, as long as the length of the air path connecting plate is lengthened, and when the use form of the air cylinder is changed, as long as the design form of a contact valve in the air cylinder cover is not changed, the air cylinder can be used for changing any air cylinder form, so that the product diversity is increased;

secondly, a ventilation air path is designed in the contact valve core and is communicated with a front cavity or a rear cavity of the cylinder, air flow enters the contact valve through the contact valve core to form an air pressure balance cavity, and the contact valve core is only under the action of the spring force of a contact spring and always keeps a stable state;

third, this application uses the button valve, prevents cylinder failure mode, has improved the stability of cylinder.

Of course, it is not necessary for any particular embodiment of the inventive concept to be implemented to achieve all of the above technical effects at the same time.

Drawings

FIG. 1 is a schematic view of the gas path principle of a prior art cylinder;

FIG. 2 is a schematic view of another prior art cylinder;

FIG. 3 is a schematic exterior view of a cylinder according to the present application;

FIG. 4 is a schematic view of the pneumatic principle of the present application;

FIG. 5 is a cut-away schematic view of the cylinder of the present application;

FIG. 6 is an enlarged schematic view of the contact valve of FIG. 5;

FIG. 7 is an enlarged schematic view of the push button valve of FIG. 5;

FIG. 8 is a cut-away view of the gas circuit connecting plate of the present application;

FIG. 9 is a cut-away schematic view of a cylinder module of the present application;

FIG. 10 is another angle cut-away view of a cylinder module according to the present application.

Detailed Description

Several preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to only these embodiments. The invention is intended to cover alternatives, modifications, equivalents, and alternatives that may be included within the spirit and scope of the invention. In the following description of the preferred embodiments of the present invention, specific details are set forth in order to provide a thorough understanding of the present invention, and it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and so forth have not been described in detail so as not to unnecessarily obscure aspects of the present invention.

Referring to fig. 3, an appearance of an integrated cylinder according to the present application is schematically illustrated, and the cylinder according to the present application includes: the pneumatic control valve module 10 is connected with the pneumatic circuit connecting plate module 20 through a screw rod, the pneumatic circuit connecting plate module 20 is connected with the air cylinder module 30 through a screw rod, and air circuit sealing is formed between the modules through O-shaped rings; the cylinder module 30 includes a cylinder rear cover portion 31, a cylinder body portion 32, and a cylinder front cover portion 33, please refer to fig. 4 at the same time, which is a schematic diagram of a pneumatic principle of the present application, the cylinder rear cover portion 31 is provided with a rear cover air passage 311 and a rear cover pilot air passage 312, the cylinder front cover portion 33 is provided with a front cover air passage 331 and a front cover pilot air passage 332, and the present invention further includes two contact valves 40, and the two contact valves 40 are respectively assembled and connected to the rear cover pilot air passage 312 and the front cover pilot air passage 332. Referring to fig. 5, in the cylinder portion 32, the cylinder piston 321 and the piston sealing ring thereon divide the cylinder portion 32 into a cylinder front cavity 322 and a cylinder rear cavity 323, the rear cover air passage 311 is communicated with the cylinder rear cavity 323, and the front cover air passage 331 is communicated with the cylinder front cavity 322.

The integrated cylinder adopts the modularized design idea of the pneumatic control valve module 10, the air path connecting plate module 20 and the cylinder module 30, when the cylinder stroke is lengthened (as long as the length of the air path connecting plate is lengthened), the use form of the cylinder is changed (when the cylinder is changed into a double-extension rod, the double-shaft form and the 3-shaft form), as long as the design form of the contact valve 40 (a contact type two-position two-way valve) in the cylinder cover is not changed, the cylinder still adopts the principle of pilot pressure difference control automatic reciprocating air path, and the air cylinder can be used for changing any cylinder form.

As shown in fig. 5 and 6, the contact valve 40 of the present application is a two-position two-way valve, preferably, a contact two-position two-way valve, which changes an air path by contacting with a cylinder piston 321, the contact valve 40 includes a contact valve core 41, a contact spring 42, a contact bushing 43 and a contact outer cover 44, the contact valve core 41 is a rod body, a valve core air path, that is, a through hole, is formed in the rod body of the contact valve core 41, the contact valve core 41 is connected to the contact bushing 43 in a penetrating manner, the contact outer covers 44 of the contact valves 40 are respectively inserted and connected to the rear cover pilot air path 312 and the front cover pilot air path 332, as shown in fig. 6, one end of the contact spring 42 is inserted and connected to the contact valve core 41, two ends of the contact spring 42 are respectively connected to the contact outer cover 44 and the contact valve core 41, as shown in the figure, one end of the contact spring 42 inserted and connected to the contact, the contact spring 42 can abut against the step, while the port at the other end of the contact spool 41 is closed, and a radial through hole is opened inside the port, and the radial through hole is communicated with the spool air passage opened in the rod body of the contact spool 41, and after assembly, the radial through hole is located in the cylinder body 32. In addition, as shown, the contact cover 44 is a cup-shaped body, the contact spring 42 abuts against the inner cup bottom of the contact cover 44, and a balance cavity is formed inside the cup body of the contact cover 44. Under the action of the spring force, the contact valve 40 is in a normally closed state and is not ventilated.

As mentioned above, according to the present invention, the ventilation air path is designed in the contact valve core 41 and is communicated with the cylinder front cavity 322 or the cylinder rear cavity 323, when the ventilation or exhaust pressure of the cylinder front cavity 322 or the cylinder rear cavity 323 changes, the air flow enters the contact valve 40 through the radial through hole formed at the inner side of the port of the contact valve core 41 to enter the balance cavity, the force values of the balance cavity are balanced under the equal stress areas, the contact valve core 41 is only under the spring force action of the contact spring 42, and the state that the radial through hole is located in the cylinder part 32 is always maintained when the acting force of the cylinder piston 321 does not exist. If no balance cavity is designed, when the air pressure in the air cylinder cavity is increased, the force acting on the area contacting the valve core 41 is larger than the spring force, the air path reversing can be triggered in advance, and the normal use of the air cylinder is influenced; of course, the air path can be introduced from the cylinder cavity to the contact valve cavity to keep the two sides of the contact valve core 41 in force balance.

As shown in fig. 5 and 7, the cylinder of the present application further includes a button valve 50, the button valve 50 is a two-position two-way valve, the button valve 50 includes a button outer cover 51, a button valve core 52, a button O-ring 53 and a button spring 54, the button valve core 52 is a rod body with a radially protruding front end, and the button outer cover 51 is a hollow cylinder body; referring to fig. 8, the gas circuit connecting plate module 20 includes a gas circuit connecting plate, and the gas circuit connecting plate is provided with a rear cover connecting gas circuit 21, a rear cover pilot connecting gas circuit 22, a front cover connecting gas circuit 23, and a front cover pilot connecting gas circuit 24, wherein the rear cover connecting gas circuit 21 and the rear cover pilot connecting gas circuit 22 are respectively connected to the rear cover gas circuit 311 and the rear cover pilot gas circuit 312 of the cylinder rear cover portion 31; the front cover connecting air path 23 and the front cover pilot connecting air path 24 are respectively connected with the front cover air path 331 and the front cover pilot air path 332 of the cylinder front cover part 33; the button valve 50 is assembled and connected with the rear cover pilot connection air passage 22, and the button spring 54, the button valve core 52, the button O-shaped ring 53 and the button outer cover 51 are sequentially put into and connected with the rear cover pilot connection air passage 22. As shown in the figure, the position of the button spring 54 inserted into the rear cover pilot connection air passage 22 is a step hole, so the button spring 54 can abut against the step, the radial protrusion of the front end of the button valve core 52 abuts against the connection of the button spring 54, the button O-ring 53 is sleeved on the button valve core 52, the rod body of the button valve core 52 is inserted into the middle through hole of the button outer cover 51, the radial protrusion of the front end of the button valve core 52 is influenced by the elastic force of the button spring 54, the button O-ring 53 is tightly pressed against the button outer cover 51, and in a normal state, the button valve 50 is in a normally-off state, so that air leakage is prevented. In the rear cover pilot connection air passage 22, the air passage is sealed by using a button valve 50; the other 3 air channels are sealed at the outer end face of the air channel connecting plate by a plug 70.

Referring to fig. 4 and 5, the cylinder of the present application further includes two air resistors 60, the air control valve module 10 includes an air control valve, the air control valve is a dual air control two-position five-way valve, the air control valve includes a valve body 11, a rear air valve cavity 12 and a front air valve cavity 13, the rear air valve cavity 12 and the front air valve cavity 13 are respectively connected to two sides of the valve body 11, an air inlet air passage of the valve body 11 is respectively connected to the rear air valve pilot air passage 14 and the front air valve pilot air passage 15, and the two air resistors 60 are respectively connected to the rear air valve pilot air passage 14 and the front air valve pilot air passage 15.

The pneumatic control valve of the present application is described below, the pneumatic control valve of the present application is a common dual pneumatic control two-position five-way valve in a pneumatic element, a valve rod is arranged in a valve body 11, a plurality of grooves are arranged on the valve rod, 6 valve rod flat rings are arranged on the valve rod flat rings, different sealing cavities are formed when the valve rod moves with the valve body 11, the valve body 11 is provided with 5 interfaces including a first exhaust port, a first working port, an air inlet, a second working port and a second exhaust port, wherein the first working port is communicated with a front cover connecting air path 23 of a gas path connecting plate, and the second working port is communicated with a rear cover connecting air path 21 of the gas path connecting plate; the left and right cover plates of the valve body 11 are respectively connected with the valve body 11 through screws, and a rear air valve cavity 12 and a front air valve cavity 13 are respectively arranged in the left and right cover plates. An air valve piston and a Y-shaped ring are respectively arranged in the rear air valve cavity 12 and the front air valve cavity 13, when air is respectively introduced into the rear air valve cavity 12 and the front air valve cavity 13, the Y-shaped ring forms air seal to push the air valve piston to drive the valve rod to move to the other side, and vice versa, the valve rod is pushed to move in 2 positions; the other 1 path of gas entering from the gas inlet passes through a rear gas valve pilot gas path 14 and a front gas valve pilot gas path 15 and is respectively introduced into a rear gas valve cavity 12 and a front gas valve cavity 13 after passing through a gas resistor 60. It is to be noted that the air resistor 60 is very important in the gas path principle, because the flow of the gas passing through the air resistor 60 is very small, and the gas supply is slow. In the principle of the gas path, gas entering the gas inlet is supplied to the rear gas valve chamber 12 and the front gas valve chamber 13 through the rear gas valve pilot gas path 14, the front gas valve pilot gas path 15 and the gas resistor 60, and is in a normally open state. The replenishment is not stopped until the air pressures P1 (intake air pressure) and P2 (intake air pressure) of the rear valve chamber 12 and the front valve chamber 13 become P0.

Referring to fig. 4, the design of the push button valve 50 as described above, when the working port is in an abnormal ventilation state, for example, after transportation or installation, and after ventilation, the pneumatic control valve stem is not in the working position, the push button valve 50 is changed from the normal open to the communication by manually pressing the push button valve core 52, the rear valve chamber 12 is exhausted, P1 is lowered, P1 < P2, and there is a pressure difference, and the front valve piston pushes the valve stem to the left limit position. The working port is used for air inlet, the cylinder rear cavity 323 is communicated, the cylinder rear cavity 323 is used for ventilation, the air cavity front cavity is used for air exhaust, the cylinder piston 321 moves forwards to complete the action of the first wheel, the operation of manually pressing the button valve core 52 is an operation mode for preventing the cylinder from failing, but the operation mode cannot be used for limiting the application, other modes such as manual screw thread exhaust and plug pulling exhaust have the same effect and are the protection range of the application, the integral type pilot pressure difference control automatic reciprocating cylinder of the application is used for controlling the output force of the cylinder by the air pressure P0 of the air inlet; and the automatic reciprocating speed is controlled by the air inlet flow.

Referring to fig. 4, the pneumatic principle of the present application is illustrated:

the pneumatic control valve is a double pneumatic control two-position five-way valve, 2 working ports of the pneumatic control valve are respectively connected with a front cover interface hole and a rear cover interface hole of the air cylinder, and meanwhile, the inner connecting holes of the pneumatic control valve are respectively connected with a rear air valve cavity 12 and a front air valve cavity 13 on the left side and the right side of the pneumatic control valve after passing through 1 air resistor 60. The signals a and b of the left and right pistons of the pneumatic control valve are kept in a normally-on state, P1 is equal to P2, the piston is stressed uniformly, and the valve rod of the pneumatic control valve is kept to be not operated in a normal state. The rear air valve cavity 12 and the front air valve cavity 13 on the left side and the right side of the air control valve are respectively connected with 1 path of air through a built-in contact valve 40 in the cylinder rear cover part 31 and the cylinder front cover part 33 of the cylinder module 30. The contact valve 40 is in a normally-off state under the action of spring force under the normal condition, when the cylinder piston 321 moves to the extreme position at the rear end of the figure, the contact valve 40 is touched to be normally-on, so that the rear air valve cavity 12 at the left side of the air control valve is deflated, the deflation flow is larger than the supplement flow due to the action of the air resistance 60, the air pressure of P1 is reduced, the P1 is less than P2, the valve rod of the air control valve is changed to the figure position under the action of pressure difference, the air is obtained from the rear cover cavity of the cylinder, and the cylinder stretches out. Vice versa, the cylinder effects a reciprocating motion, so it is called a pilot pressure difference controlled automatic reciprocating cylinder.

The following description of the operating state is provided:

when the air inlet of the pneumatic control valve is used for air inlet, the air flow P0 also flows to the rear valve cavity 12 and the front valve cavity 13, so that the air pressure P1 of the rear valve cavity 12 is equal to the air pressure P2 of the front valve cavity 13, the left and right valve pistons are stressed uniformly, the valve rod is kept still, and at the moment, 2 states exist:

in the first state, the valve rod is in the right or left limit position, and the first working port or the second working port starts to intake air. If the first working port is used for air intake, the first working port is communicated with the cylinder front cavity 322, the cylinder front cavity 322 is ventilated, the cylinder rear cavity 323 is exhausted, and the cylinder piston 321 moves backwards. When the cylinder piston 321 contacts the contact valve 40 on the cylinder rear cover part 31, as shown in the figure, the contact valve 40 is changed from normally closed to open, the air flow of the rear air valve cavity 12 is exhausted to the atmosphere through the air passage, because the air resistance 60 on the air control valve exists, the make-up air flow is smaller than the exhaust air flow, the P1 is reduced, the P1 is less than the P2, the pressure difference exists, and the valve rod is pushed to the left limit position by the right air valve piston. The second working port is used for air inlet and is communicated with the cylinder rear cavity 323, the cylinder rear cavity 323 is used for ventilation, the air cavity front cavity is used for air exhaust, and the cylinder piston 321 moves forwards. When the cylinder piston 321 leaves the contact valve core 41 of the cylinder rear cavity 323, the contact valve 40 on the cylinder rear cover part 31 is in a normally-off state again. In the air inlet air charging state, P1 is P2, and the valve rod keeps the position. When the cylinder piston 321 touches the contact valve core 41 of the contact valve 40 of the cylinder front cover part 33, the switching of a new air path is completed, and the cylinder reciprocating motion is formed.

In the second state, when the cylinder is in a vibration state during transportation or installation, the valve rod is not located at the right or left limit position, and at this time, the cylinder piston 321 may not be manually located at the two limit positions because the cylinder piston rod is not exposed. At this time, the push button valve core 52 is manually pushed to change the push button valve 50 from the normally-off state to the communication state, the rear valve chamber 12 is exhausted, the P1 descends, the P1 < P2 has pressure difference, and the front valve piston pushes the valve rod to the left limit position. The second working port is used for air inlet and is communicated with the cylinder rear cavity 323, the cylinder rear cavity 323 is used for ventilation, the air cavity front cavity is used for air exhaust, and the cylinder piston 321 moves forwards to complete the first round of action.

In summary, due to the adoption of the technical characteristics, compared with the prior art, the invention has the following advantages and positive effects:

firstly, the air cylinder adopts a modularized design idea of an air control valve module, an air path connecting plate module and an air cylinder module, when the stroke of the air cylinder is lengthened, as long as the length of the air path connecting plate is lengthened, and when the use form of the air cylinder is changed, as long as the design form of a contact valve in the air cylinder cover is not changed, the air cylinder can be used for changing any air cylinder form, so that the product diversity is increased;

secondly, a ventilation air path is designed in the contact valve core and is communicated with a front cavity or a rear cavity of the cylinder, air flow enters the contact valve through the contact valve core to form an air pressure balance cavity, and the contact valve core is only under the action of the spring force of a contact spring and always keeps a stable state;

third, this application uses the button valve, prevents cylinder failure mode, has improved the stability of cylinder.

The preferred embodiments of the invention are provided solely to aid in the illustration of the invention. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents. The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and it is intended that all equivalent variations and modifications of the present invention as those skilled in the art can be made without departing from the spirit and scope of the present invention.