CN206121885U - A nitrogen explodes device for crushing equipment - Google Patents

Abstract

The utility model discloses a nitrogen explodes device for crushing equipment, plunger or piston rod in including the cylinder body and arranging the cylinder body in, form the cylinder body chamber that has certain confined space in the cylinder body be provided with on the cylinder body with the gas pocket of cylinder body chamber intercommunication the cylinder body intracavity is full of the nitrogen gas that has certain pressure in the cylinder body, be provided with the guide holder between cylinder body and plunger or the piston rod, the guide holder passes through connecting piece fixed connection together with the cylinder body. The utility model discloses a nitrogen explodes the device because its guide holder passes through bolted connection with the cylinder body for the guide holder is more firm, can prevent that nitrogen from exploding impact damage, consequently, can be fit for nitrogen gas high pressure operation state, and it is convenient that stable in structure is reliable, the installation is made.

Description

A kind of quick-fried device of the nitrogen for disintegrating apparatus

Technical field

This utility model belongs to flexible member technical field, the quick-fried device of the more particularly to a kind of nitrogen for disintegrating apparatus.

Background technology

Nitrogen is a kind of noble gases, with ins and outs：When being acted on by external force, nitrogen is compressible, and will can compress Energy storage is got up, and when unloading external force stopping compression, nitrogen occurs rapid expansion, the quick-fried phenomenon of generation nitrogen.Nitrogen compression and it is swollen During swollen, when control is in certain pressure scope, nitrogen is substantially at adiabatci condition, and its heat stability is good, is difficult to change into Heat, meanwhile, nitrogen can obtain certain elastic force pressure in the quick-fried expansion process of nitrogen, therefore wide with nitrogen spring made by nitrogen It is general to be applied to the fields such as mould, automobile, electronics, instrument.This nitrogen spring compares traditional flexible member, small volume, pressure Greatly, life-span length, can reach more than 1,000,000 times, while in the course of the work, can keep more constant elastic force pressure.

It is smaller that the structure of existing nitrogen spring is primarily adapted for use in volume, it is desirable to the less big engineering equipment of the quick-fried power of nitrogen In, and large-scale engineering equipment, the especially requirement in engineering disintegrating apparatus field cannot be applied to, and in engineering disintegrating apparatus In, the broken such as material such as Rock And Soil, cement concrete, armored concrete is commonly used to, disintegrating apparatus is required to export Power it is big, can be suitable for complex work environment, efficient breaking capacity, consolidate firm structure etc., therefore, traditional nitrogen spring There is certain limitation for disintegrating apparatus, especially the mode of snap ring-type fixed guide seat, it is relatively large in diameter, snap ring is installed During more inconvenience, while snap ring will bear the effect of huge nitrogen quick-fried power, easily failure causes explosion.

In addition, existing nitrogen spring can not be adapted to very well for complicated working environment, such as due to misoperation caused by Equipment lands suddenly, or makes it bear excessive pressure effect because engineering specifications complexity causes device to cross stroke.

Utility model content

Goal of the invention of the present utility model is：For above-mentioned problem, there is provided it is high that one kind can be applied to nitrogen Pressure working condition, significantly improves disintegrating apparatus performance, the nitrogen for disintegrating apparatus that Stability Analysis of Structures is reliable and installation is easily manufactured Quick-fried device.

The technical scheme implementation of this utility model technology：A kind of quick-fried device of the nitrogen for disintegrating apparatus, including cylinder body And the plunger that is placed in cylinder body or piston rod, the cylinder chamber with certain sealing space is formed in the cylinder body, in the cylinder The pore connected with cylinder chamber is provided with body, in the cylinder body intracavity full of the nitrogen with certain pressure, it is characterised in that： Guide holder is provided with the cylinder body, between cylinder body and plunger or piston rod, the guide holder is solid by connector with cylinder body Surely link together.

The quick-fried device of nitrogen for disintegrating apparatus described in the utility model, its described guide holder by middle part targeting part, The coupling part of bottom and the limit part composition at top, the coupling part of the guide holder and the bottom mounting portion of cylinder body It is bolted to connection, the limit part of the guide holder is used to be controlled the limit inferior stroke of plunger or piston rod, Sealing device is provided between the targeting part and plunger or piston rod of the guide holder.

The quick-fried device of nitrogen for disintegrating apparatus described in the utility model, coupling part and the cylinder body of its guide holder Bottom mounting portion is bolted to connection together by the way of flange connection, the plunger head radially side Form lobe or the piston rod part is socketed with piston, the lobe of the plunger head or the work of piston rod part Plug coordinates with the limit part of guide holder, forms the lower limit position of plunger or piston rod.

The quick-fried device of nitrogen for disintegrating apparatus described in the utility model, it is connected with the plunger or piston rod bottom Limiting plate is installed, the installation limiting plate is used to be controlled the limit superior stroke of plunger or piston rod, the plunger or work Stopper rod is less than the plunger or piston rod inner chamber of cylinder block in lower limit position by the stroke that lower limit position moves to upper extreme position The free height a of body, when the plunger or piston rod movement are to upper extreme position, the installation limit of the plunger or piston rod bottom Position plate is contacted with the bottom of guide holder.

The quick-fried device of nitrogen for disintegrating apparatus described in the utility model, its described external diameter or the length of side for installing limiting plate is big In plunger or the external diameter of piston rod, when the plunger or piston rod are in lower limit position, the installation limiting plate upper surface is extremely The distance between guide holder lower surface is plunger or the high-low limit motion amplitude b of piston rod, i.e., plunger or piston rod are by lower pole Extreme position moves to upper extreme position or moves to the stroke of lower limit position by upper extreme position.

The quick-fried device of nitrogen for disintegrating apparatus described in the utility model, its described sealing device include the first sealing ring, Second sealing ring, the first dust ring, the second dust ring and sealing gasket, are provided with multiple annular grooves on the guide holder, First sealing ring is arranged between guide holder and plunger or piston rod, and is nested near the medial wall on guide holder top In annular groove, second sealing ring is arranged between guide holder and cylinder body, and is nested near the outside on guide holder top In the annular groove of wall, first dust ring is arranged between guide holder and plunger or piston rod, and is nested near guiding In the annular groove of the medial wall of seat bottom, second dust ring is arranged between guide holder and cylinder body, and is nested in close In the annular groove of the lateral wall of guide holder bottom, the sealing gasket is arranged on the bottom mounting portion and guide holder bottom of cylinder body Coupling part between.

The quick-fried device of nitrogen for disintegrating apparatus described in the utility model, its guide holder and plunger or piston rod it Between be provided with least one guide ring, and be nested in the annular groove of the medial wall of guide holder.

The quick-fried device of nitrogen for disintegrating apparatus described in the utility model, its pore is arranged on the top of cylinder body, institute State pore and be connected with air valve composition, the air valve composition includes relief valve and charge valve.

The quick-fried device of nitrogen for disintegrating apparatus described in the utility model, its described cylinder base or guide holder bottom and post Dust cover is set between plug or piston rod bottom, and the tensile elongation of the dust cover is not less than plunger or the high-low limit of piston rod Motion amplitude.

The quick-fried device of nitrogen for disintegrating apparatus described in the utility model, its described cylinder body inside top wall is provided with downwards Extension, the extension is used to be controlled the limit superior stroke of plunger or piston rod, the extension The distance between the lower inwall in bottom surface and cylinder body top c meets safety travel requirement, when plunger or piston rod movement are to limit superior position When putting, the plunger or piston rod part are contacted with extension.

Based on above-mentioned technical proposal, the beneficial effects of the utility model are：

1st, the quick-fried device of nitrogen of the present utility model is bolted due to its guide holder and cylinder body so that guide holder is more steady Gu, the quick-fried impact failure of nitrogen can be prevented, therefore, nitrogen high-pressure work state, Stability Analysis of Structures reliability can be adapted to.

2nd, guide holder is connected with cylinder body by flange in this utility model so that the quick-fried device of nitrogen install manufacture process in more Plus it is convenient.

3rd, the quick-fried device of nitrogen of the present utility model is accurately controlled to the stroke up and down of plunger or piston rod, applicable In complex work environment, the purpose of the quick-fried device of effective protection nitrogen is played.

4th, the quick-fried device of nitrogen of the present utility model can make full use of the quick-fried property of the nitrogen of nitrogen, for disintegrating apparatus in, can be notable Improve the performance of disintegrating apparatus, comprising reduction noise, strengthen the one of impulsive force, raising crushing efficiency and raising capacity usage ratio Plant or various features.

Description of the drawings

Fig. 1 is three-dimensional structure diagram of the present utility model.

Fig. 2 is the section of structure of the quick-fried device of plunger type nitrogen in this utility model.

Fig. 3 is the section of structure of the quick-fried device of piston type nitrogen in this utility model.

Fig. 4 is a kind of upper limit embodiment of the quick-fried device of nitrogen in this utility model.

Fig. 5 is another kind of upper limit embodiment of the quick-fried device of nitrogen in this utility model.

Fig. 6 is a kind of embodiment of the quick-fried device of nitrogen containing dust cover in this utility model.

Labelling in figure：1 is the quick-fried device of nitrogen, and 2 is cylinder body, and 22 is cylinder chamber, and 25 is extension, and 231 is pore, and 232 are Attachment means, 241 is bottom mounting portion, and 3 is guide holder, and 31 is targeting part, and 32 is coupling part, and 33 is limit part, 4 For plunger or piston rod, 41 is lobe, and 42 is piston, and 44 to install limiting plate, and 5 is sealing device, and 51 is the first sealing ring, 52 second sealing rings are that 53 is the first dust ring, and 54 is the second dust ring, and 55 is sealing gasket, and 6 is guide ring, and 71 is relief valve, 72 is charge valve, and 8 is dust cover.

Specific embodiment

Below in conjunction with the accompanying drawings, this utility model is described in detail.

Although this utility model admits of the embodiment of multi-form, the specification and drawings disclose only such as this reality With some particular forms of new example.But this utility model is not intended to be limited to described embodiment.This utility model Scope be given in the appended claims.

Describe for convenience, embodiment of the present utility model is illustrated with being typically oriented, the orientation causes to work as the quick-fried dress of nitrogen Put when vertically standing with plunger or piston rod as bottom, air valve is top, " longitudinal direction ", " horizontal " used in description " on ", D score, The term such as "front", "rear", " vertical ", " level ", " top ", " bottom ", " interior ", " outward " is both referred to this position and uses, only It is to describe for the ease of describing this utility model and simplifying, rather than indicates or imply that the device or element of indication there must be spy Fixed orientation and specific azimuth configuration and operation, it should be understood that this utility model can be differently configured from described position Orientation is manufactured, is deposited, is transported, used and sold.

The quick-fried device of nitrogen of the present utility model is applied to various external carriers, is particularly suited for a kind of Rock And Soil and coagulating cement The disintegrating apparatus of soil and armored concrete.Although although the disintegrating apparatus its details is not shown or described, disintegrating apparatus sheet Body does not form any part of main aspect of the present utility model, therefore is not intended to be limited.People in the art Member is it will also be understood that novel and non-obvious creative aspect is had only in the quick-fried device of nitrogen described in the utility model Specifically embodied.

As illustrated in fig. 1 and 2, the current one of which preferred embodiment of the quick-fried device of nitrogen of the present utility model is shown.Institute In the preferred embodiment for showing, the quick-fried device unit of nitrogen in preferred embodiment is referred to reference 1.

As shown in Fig. 2 showing a kind of cross-section structure of the quick-fried device 1 of plunger type nitrogen, it includes cylinder body 2 and is placed in cylinder body Plunger 4 in 2, the cylinder body is the structure of bottom opening, and the cylinder chamber with certain sealing space is formed in the cylinder body 2 22, the pore 231 connected with cylinder chamber 22 is provided with the cylinder body 2, full of with a level pressure in the cylinder chamber 22 The nitrogen of power, the plunger is used for compressed nitrogen and receives nitrogen expansion power, and there is the cylinder chamber enough spaces to provide The space that plunger is moved in high-low limit.The cross section outline of the cylinder body can have different configuration, for example comprising but do not limit In circle, ellipse, rectangle, square one or more of combination, cylinder wall can have elongated consistent, mutation or gradually along longitudinal direction The configuration of change, such as by upper and lower various sizes of circle（Or rectangle or square）The convex cylinder body of composition.

Wherein, the pore 231 is arranged on the top of cylinder body 2, and the pore 231 is connected with air valve composition, the air valve group Into can be used to be filled with nitrogen or discharge nitrogen, distinguishingly, air valve can also be used for the situation for needing to adjust gas pressure, such as when outer Boundary's environment（The factors such as power, temperature）Change, cause nitrogen pressure force value in cylinder chamber 22 exceed regulation reasonable working range or Beyond secure setting when, need to carry out release, or due to disintegrating apparatus work a period of time after, nitrogen partial leakage causes Pressure drop, when needs are supplemented, or the work condition environment more complicated in order to adapt to disintegrating apparatus, need dynamic adjustment nitrogen During atmospheric pressure, can realize adjusting by air valve composition.The cylinder body top is additionally provided with the attachment means for external equipment 232, the attachment means 232 can be the extension at the top of cylinder body laterally, or the connection arranged on cylinder body Hole.

In the present embodiment, the air valve is constituted includes relief valve 71 and charge valve 72, and relief valve and charge valve can be independent Arrange.In the quick-fried device course of work of nitrogen, by external high temperature environment or other reasonses, nitrogen pressure in cylinder chamber 22 is caused to surpass When crossing the pressure of normal work setting, the automatic exhaust pressure relief of relief valve keeps nitrogen pressure to stablize.Alternatively, the air valve Relief valve and charge valve in composition may also set up integral structure.

As shown in Fig. 2 being provided with guide holder 3 in the cylinder body 2, between cylinder body 2 and plunger 4, the guide holder 3 is by The coupling part 32 of the targeting part 31, bottom in portion and the limit part 33 at top are constituted, the coupling part of the guide holder 3 32 be bolted to connection by the way of flange connection with the bottom mounting portion 241 of cylinder body 2 together with, the attachment structure Guide holder can be made solid and reliable, and then make guide holder to bear the quick-fried power of bigger nitrogen, the limit part 33 of the guide holder 3 is used for The limit inferior stroke of plunger 4 is controlled, radially side forms lobe 41, the plunger head to the plunger head Lobe 41 coordinate with the limit part 33 of guide holder 3, formed plunger 4 lower limit position, the guide part of the guide holder 3 Divide and sealing device 5 be provided between 31 and plunger 4, the sealing device is used to prevent helium leak and external dust from entering, The targeting part 31 of the guide holder 3 is used to keep plunger 4 to pump, and keeps dynamic matching relationship with it.

Alternatively, as shown in figure 3, showing the cross-section structure of another kind of embodiment of the quick-fried device 1 of nitrogen, the quick-fried device of the nitrogen is The quick-fried device of piston type nitrogen, in this embodiment, with piston rod plunger is replaced, meanwhile, arrange at the position near the top of piston rod 4 There is piston 42, on the piston 42 guidance tape is nested with（It is not shown）, the piston 42 and cylinder body 2 keep dynamic fit relation, The piston 42 coordinates with the limit part 33 of guide holder 3, forms the lower limit position of piston rod.

For ensure the nitrogen safe and stable work of quick-fried device 1, the quick-fried device 1 of nitrogen be provided with it is various offer plungers or piston rod 4 it is upper Limit travel control mode, this limit superior Stroke Control causes the quick-fried device of nitrogen suitable for using under complex work environment, for example, Because misoperation causes disintegrating apparatus to land suddenly, or due to engineering specifications complexity（Such as surface irregularity）, cause The quick-fried device of nitrogen crosses stroke so as to bear excessive pressure condition.

A kind of embodiment for preferably controlling plunger or the limit superior stroke of piston rod 4, as shown in figure 4, in the plunger or The bottom of piston rod 4 is connected with installation limiting plate 44, and the limiting plate 44 of installing is for the limit superior stroke to plunger or piston rod 4 It is controlled, the external diameter or the length of side for installing limiting plate 44 is more than the external diameter of plunger or piston rod 4, when the plunger or piston In lower limit position, the distance between described upper surface of installation limiting plate 44 to the lower surface of guide holder 3 is plunger or piston to bar 4 The high-low limit motion amplitude b of bar 4, i.e. plunger or piston rod 4 move to upper extreme position or by upper pole by lower limit position Extreme position moves to the stroke of lower limit position, and the plunger or the high-low limit motion amplitude b of piston rod 4 are less than plunger or piston The free height a of the inner chamber body of cylinder body 2 in lower limit position of bar 4, and both differences c meet safety travel requirement, wherein, free height A referred to when plunger or piston rod 4 move to lower limit position, inwall and plunger or the table at the top of piston rod 4 at the top of cylinder body 2 The distance between face, when the plunger or piston rod 4 move to upper extreme position, the peace of the plunger or the bottom of piston rod 4 Dress limiting plate 44 is contacted with the bottom of guide holder 3.

Wherein, the sealing device 5 includes that the first sealing ring 51, the second sealing ring 52, the first dust ring 53, second are dust-proof Circle 54 and sealing gasket 55, are provided with multiple annular grooves on the guide holder 3, and first sealing ring 51 is arranged on guiding Between seat 3 and plunger or piston rod 4, and it is nested in the annular groove of the medial wall on the top of guide holder 3, described second is close Seal 52 is arranged between guide holder 3 and cylinder body 2, and is nested in the annular groove of the lateral wall on the top of guide holder 3, institute State the first dust ring 53 to be arranged between guide holder 3 and plunger or piston rod 4, and be nested near the inner side of the bottom of guide holder 3 In the annular groove of wall, second dust ring 54 is arranged between guide holder 3 and cylinder body 2, and is nested near the bottom of guide holder 3 In the annular groove of the lateral wall at end, the sealing gasket 55 is arranged on the bottom mounting portion 241 and the bottom of guide holder 3 of cylinder body 2 Coupling part 32 between；Be provided between the guide holder 3 and plunger or piston rod 4 at least together with there is high-wearing feature Guide ring 6, preferentially arranges twice, and the guide ring preferentially selects polytetrafluoroethylmaterial material, but is also not excluded for other applicable materials Material, the guide ring 6 is arranged between the first sealing ring 51 and the first dust ring 53, and be nested in the medial wall of guide holder 3 In annular groove.Be contemplated to, in order to improve sealing effectiveness and reduce friction, can in sealing device and guide ring and plunger or Fit-up gap injection lubricating oil between piston rod 4.

Another kind preferably controls the embodiment of plunger or the limit superior stroke of piston rod 4, as shown in figure 5, the cylinder body 2 is pushed up Portion medial wall is provided with downward extension 25, and the extension 25 is used for the limit superior stroke to plunger or piston rod 4 It is controlled, the distance between lower inwall in bottom surface and the top of cylinder body 2 of the extension 25 c meets safety travel requirement, when When plunger or piston rod 4 move to upper extreme position, the plunger or the top of piston rod 4 contact with extension 25.

As shown in fig. 6, the dust in the dust or external environment in order to prevent the course of work enters the cylinder of the quick-fried device 1 of nitrogen In body cavity 22, dust cover 8 is set between the bottom of the cylinder body 2 or the bottom of guide holder 3 and plunger or the bottom of piston rod 4, it is described The tensile elongation of dust cover 8 is not less than the high-low limit motion amplitude of plunger or piston rod 4, to ensure that the quick-fried device of nitrogen has upper The space of lower limit position motion.

Erection sequence of the present utility model is：First it is directed to seat to be socketed from the bottom of plunger or piston rod, is then directed to Seat is fixedly connected with cylinder body, then plunger or the connection of piston rod bottom are installed into limiting plate.When parts are changed in maintenance, order is just On the contrary.

Above content is to combine specific optimal technical scheme further detailed description of the utility model, it is impossible to Identification is of the present utility model to be embodied as only limitation and these explanations.For the ordinary skill of this utility model art For personnel, on the premise of this utility model design has not been taken off, some simple deduction or replace can also be made, and all are not Depart from spirit and scope of the present utility model technical scheme and and its improve, its all should cover right of the present utility model will In seeking scope.

Claims (10)

1. a kind of quick-fried device of nitrogen for disintegrating apparatus, including cylinder body（2）And it is placed in cylinder body（2）Interior plunger or piston rod （4）, the cylinder body（2）It is interior to form the cylinder chamber with certain sealing space（22）, in the cylinder body（2）On be provided with and cylinder body Chamber（22）The pore of connection（231）, in the cylinder chamber（22）It is interior full of the nitrogen with certain pressure, it is characterised in that： The cylinder body（2）Interior, cylinder body（2）With plunger or piston rod（4）Between be provided with guide holder（3）, the guide holder（3）With cylinder body （2）It is fixed together by connector.

2. the quick-fried device of the nitrogen for disintegrating apparatus according to claim 1, it is characterised in that：The guide holder（3）By in The targeting part in portion（31）, bottom coupling part（32）And the limit part at top（33）Composition, the guide holder（3）'s Coupling part（32）With cylinder body（2）Bottom mounting portion（241）It is bolted to connection, the guide holder（3）It is spacing Part（33）For to plunger or piston rod（4）Limit inferior stroke be controlled, the guide holder（3）Targeting part（31） With plunger or piston rod（4）Between be provided with sealing device（5）.

3. the quick-fried device of the nitrogen for disintegrating apparatus according to claim 2, it is characterised in that：The guide holder（3）Company Socket part point（32）With cylinder body（2）Bottom mounting portion（241）It is bolted to connection one by the way of flange connection Rise, radially side forms lobe to the plunger head（41）Or the piston rod part is socketed with piston（42）, institute State the lobe of plunger head（41）Or the piston of piston rod part（42）With guide holder（3）Limit part（33）Coordinate, Form plunger or piston rod（4）Lower limit position.

4. the quick-fried device of the nitrogen for disintegrating apparatus according to claim 1, it is characterised in that：In the plunger or piston rod （4）Bottom is connected with installation limiting plate（44）, the installation limiting plate（44）For to plunger or piston rod（4）Limit superior row Journey is controlled, the plunger or piston rod（4）The stroke of upper extreme position is moved to less than plunger or work by lower limit position Stopper rod（4）The cylinder body in lower limit position（2）The free height a of inner chamber body, when the plunger or piston rod（4）Move to limit superior During position, the plunger or piston rod（4）The installation limiting plate of bottom（44）With guide holder（3）Bottom contact.

5. the quick-fried device of the nitrogen for disintegrating apparatus according to claim 4, it is characterised in that：The installation limiting plate（44） External diameter or the length of side more than plunger or piston rod（4）External diameter, when the plunger or piston rod（4）In lower limit position, institute State installation limiting plate（44）Upper surface is to guide holder（3）The distance between lower surface is plunger or piston rod（4）High-low limit Motion amplitude b, i.e. plunger or piston rod（4）Upper extreme position is moved to by lower limit position or is moved to by upper extreme position The stroke of lower limit position.

6. the quick-fried device of the nitrogen for disintegrating apparatus according to claim 2, it is characterised in that：The sealing device（5）Bag Include the first sealing ring（51）, the second sealing ring（52）, the first dust ring（53）, the second dust ring（54）And sealing gasket（55）, In the guide holder（3）On be provided with multiple annular grooves, first sealing ring（51）It is arranged on guide holder（3）With plunger or Piston rod（4）Between, and be nested near guide holder（3）In the annular groove of the medial wall on top, second sealing ring （52）It is arranged on guide holder（3）With cylinder body（2）Between, and be nested near guide holder（3）The annular groove of the lateral wall on top It is interior, first dust ring（53）It is arranged on guide holder（3）With plunger or piston rod（4）Between, and be nested near guide holder （3）In the annular groove of the medial wall of bottom, second dust ring（54）It is arranged on guide holder（3）With cylinder body（2）Between, and It is nested near guide holder（3）In the annular groove of the lateral wall of bottom, the sealing gasket（55）It is arranged on cylinder body（2）Bottom Mounting portion（241）With guide holder（3）The coupling part of bottom（32）Between.

7. the quick-fried device of the nitrogen for disintegrating apparatus according to claim 6, it is characterised in that：In the guide holder（3）With Plunger or piston rod（4）Between be provided with least one guide ring（6）, the guide ring（6）It is nested in guide holder（3）Inner side In the annular groove of wall.

8. the quick-fried device of the nitrogen for disintegrating apparatus according to claim 1, it is characterised in that：The pore（231）Arrange In cylinder body（2）Top, the pore（231）Air valve composition is connected with, the air valve composition includes relief valve（71）And inflation Valve（72）.

9. the quick-fried device of the nitrogen for disintegrating apparatus according to claim 1, it is characterised in that：The cylinder body（2）Bottom or Guide holder（3）Bottom and plunger or piston rod（4）Dust cover is set between bottom（8）, the dust cover（8）Tensile elongation not Less than plunger or piston rod（4）High-low limit motion amplitude.

10. the quick-fried device of the nitrogen for disintegrating apparatus according to any one in claim 3 to 9, it is characterised in that：It is described Cylinder body（2）Inside top wall is provided with downward extension（25）, the extension（25）For to plunger or piston rod （4）Limit superior stroke be controlled, the extension（25）Bottom surface and cylinder body（2）The distance between the lower inwall in top c Safety travel requirement is met, when plunger or piston rod（4）When moving to upper extreme position, the plunger or piston rod（4）Top With extension（25）Contact.