CN112050072A

CN112050072A - Liquefied natural gas cylinder for vehicle

Info

Publication number: CN112050072A
Application number: CN201910488773.1A
Authority: CN
Inventors: 夏园园; 孟新军; 刘蓓蓓; 史澄辉; 段武; 惠阿玲
Original assignee: Xi'an Desen New Energy Equipment Co ltd
Current assignee: Xi'an Desen New Energy Equipment Co ltd
Priority date: 2019-06-06
Filing date: 2019-06-06
Publication date: 2020-12-08

Abstract

The invention provides a liquefied natural gas cylinder for a vehicle, which comprises a shell and an inner container, wherein a heat insulation space is formed between the shell and the inner container, the front end of the inner container is connected to the shell through a front end supporting device, and the rear end of the inner container is connected to the shell through a rear end supporting device of the inner container and a rear end supporting device of the outer container, the inner container is made of aluminum alloy, the shell is made of stainless steel, the front end and the rear end of the inner container are respectively provided with an inner front end socket and an inner rear end socket, and the front end and the rear end of the shell are respectively provided with an outer front end socket. The front end supporting device adopts a lock riveting structure to solve the problem of connection of stainless steel and aluminum alloy, and the rear end supporting device consists of an aluminum alloy inner container rear end supporting device and a stainless steel outer container rear end supporting device together, so that the soft connection of the supporting structure is realized. The rear end of the inner container is also provided with an excessive filling prevention device, the front and rear seal heads of the inner container are respectively provided with a molecular sieve, and the rear seal head of the shell is provided with palladium oxide, so that the vacuum degree in the heat insulation space in the bottle can be maintained, and toxic gas can be effectively removed.

Description

Liquefied natural gas cylinder for vehicle

Technical Field

The invention relates to the technical field of gas cylinders, in particular to a liquefied natural gas cylinder for a vehicle.

Background

At present, a general large-volume gas cylinder (750L-1000L) for a vehicle liquefied natural gas cylinder mostly adopts an inner-layer structure and an outer-layer structure, heat insulation materials are filled between an inner container and a shell, and an interlayer space is vacuumized; the inner container is fixed in the outer shell through a hard support at the front end and a soft support structure at the rear end. All the main materials of the gas cylinder are austenitic stainless steel, the weight of 1 CDPW850-1000-1.59 type gas cylinder bare cylinder is about 500kg, and the total weight of the frame and pipeline assembly is about 700kg, and the gas cylinder is used as a heavy truck oil tank and is placed behind a cab.

The aluminum alloy inner container is the direction of vehicle LNG gas cylinder lightweight, and because of the particularity of interlayer vacuum, the connection between the aluminum alloy inner container and the stainless steel shell becomes the key for realizing lightweight. The thermal conductivity of the aluminum alloy is 13 times that of the stainless steel, and the requirement of heat insulation of the LNG gas cylinder for the vehicle is considered, so that the use of aluminum alloy materials at the supporting position is avoided or reduced. Therefore, how the aluminum alloy inner container is connected with the stainless steel shell, whether the connection of the stainless steel supporting structure and the aluminum alloy inner container is reliable or not directly influences the strength, the vacuum degree and the like of the gas cylinder.

In view of the above technical problems, the present inventors have long studied and practiced the present invention.

Disclosure of Invention

In order to solve the technical problems, the invention provides the liquefied natural gas cylinder for the vehicle, which not only can stably install the inner container, but also can effectively reduce the weight of the gas cylinder and effectively reduce heat leakage by redesigning and reasonably arranging the inner container.

On the basis, in order to further reduce the weight and the heat leakage, the invention also improves the front end supporting structure and the rear end supporting structure in the liquefied natural gas cylinder.

In addition, the gas cylinder of the liquefied natural gas is provided with the adsorption device at a reasonable position, so that the vacuum degree in the heat insulation space in the cylinder can be maintained, and toxic gas can be effectively removed.

The technical scheme adopted by the invention is as follows:

the liquefied natural gas cylinder for the vehicle comprises a shell and an inner container, wherein a heat insulation space is formed between the shell and the inner container, the front end of the inner container is connected to the shell through a front end supporting device, and the rear end of the inner container is connected to the shell through an inner container rear end supporting device and an outer container rear end supporting device; the inner container is made of aluminum alloy, the shell is made of stainless steel, an inner front sealing head and an inner rear sealing head are arranged at the front end and the rear end of the inner container respectively, and an outer front sealing head and an outer rear sealing head are arranged at the front end and the rear end of the shell respectively.

Furthermore, the front end supporting device comprises a first sealing plate, a second sealing plate, a supporting small pipe, a supporting middle pipe, a supporting cylinder body and a pipeline distribution head, wherein a supporting mounting hole is formed in the inner front end socket, the first sealing plate seals the supporting mounting hole and is fixedly connected with the inner front end socket, the second sealing plate is welded to the outer side of the first sealing plate, the first sealing plate and the second sealing plate are reinforced through a rivet, the inner side of the first sealing plate is fixedly connected with one end of the supporting cylinder body, one end of the supporting middle pipe penetrates through the first sealing plate and the second sealing plate and is fixedly connected with the first sealing plate and the second sealing plate, the other end of the supporting middle pipe is located in the supporting cylinder body, the supporting small pipe is sleeved in the supporting middle pipe, and one end of the supporting small pipe.

Furthermore, the inner front end socket, the first sealing plate and the support cylinder are all made of aluminum alloy, and the second sealing plate, the pipeline distribution head, the rivet, the support small pipe and the support middle pipe are all made of stainless steel.

The front end supporting device further comprises a neck cover, a third sealing plate and a fourth sealing plate, the third sealing plate and the fourth sealing plate are sequentially fixed at one end, away from the first sealing plate, of the supporting cylinder body, and the neck cover is fixed at one end, away from the first sealing plate, of the supporting middle pipe; the third shrouding is the aluminum alloy, the material of neck lid, fourth shrouding is the stainless steel.

Further, the liner rear end supporting device comprises an inner rear end socket reinforcing plate, a rear end supporting shaft and a rear end supporting small end socket, and the rear end supporting small end socket and the inner rear end socket reinforcing plate are respectively fixed on the inner side and the outer side of the inner rear end socket; the outer liner rear end supporting device comprises a rear end supporting plate and a shaft sleeve, the rear end supporting plate is connected to the inner surface of the outer rear end socket, and the shaft sleeve is fixed on the rear end supporting plate; one end of the rear end support shaft is sequentially and fixedly arranged on the inner rear end enclosure reinforcing plate, the inner rear end enclosure and the rear end support small end enclosure in a penetrating mode, and the other end of the rear end support shaft penetrates through the shaft sleeve.

Furthermore, clearance fit is formed between the rear end support shaft and the shaft sleeve.

Furthermore, the material of interior back head, interior back head stiffening plate, rear end back shaft and the little head of rear end support is the aluminum alloy, the material of outer back head, rear end backup pad and axle sleeve is the stainless steel.

Furthermore, the inner side of the inner rear end socket is provided with an excessive filling prevention device, the excessive filling prevention device comprises an excessive cylinder and an excessive end socket, the rear end of the excessive cylinder is connected with the excessive end socket, the front end of the excessive cylinder is connected with the inner side of the inner rear end socket, so that a closed cavity is formed, and the excessive end socket or the excessive cylinder is provided with a small hole communicated with the inner cavity of the inner container.

Further, the volume of the overfill prevention device is 8% of the total volume of the gas cylinder.

Furthermore, the inner front end enclosure and the inner rear end enclosure are both provided with molecular sieves, and the outer rear end enclosure is provided with palladium oxide.

Compared with the prior art, the invention has the beneficial effects that:

1. the inner container is made of aluminum alloy, and by taking a 1000L gas cylinder of our company as an example, the weight reduction of 103kg can be realized, the weight reduction of the inner container is 44.3%, and the weight reduction of the liquefied natural gas cylinder for vehicles is 26.5%.

2. The front end supporting device adopts a lock riveting structure to solve the connection problem of stainless steel and aluminum alloy, is connected by a reliable mechanical structure after welding, comprehensively considers the problems of heat leakage and interlayer vacuum, and effectively solves the problems of large heat leakage of aluminum alloy and volatile vacuum caused by failure of a welding line.

3. The rear end supporting device is composed of the rear end supporting device of the aluminum alloy inner container and the rear end supporting device of the stainless steel outer container together, so that the soft connection of the supporting structure is realized, the weight is effectively reduced, the heat leakage is reduced, and the static evaporation rate of the gas cylinder is reduced.

4. This automobile-used liquefied natural gas cylinder inner bag rear end is provided with prevents the excessive filling device, the device is including preventing that the excessive filling head fills and prevent the excessive filling barrel, it has the aperture to prevent opening of excessive filling head bottom, when sensing liquid full-filling when the topping-up, prevent still having most gas in the excessive filling device, the liquid can flow until balanced in preventing the excessive filling device in the bottle after stopping the topping-up, thereby make the inner bag all can have certain gas existence with the top of preventing the excessive filling device, thereby realized preventing that the gas cylinder from filling the overflow, the effect of the harmless save time of protection gas cylinder safety in utilization and pressure boost.

5. The front and rear end sockets of the inner container are respectively provided with a molecular sieve which is used for absorbing high molecular particles such as water, methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide and the like during vacuumizing, thereby ensuring the vacuum degree of the heat insulation space. Palladium oxide is arranged on the shell rear end socket and can absorb residual toxic gas welded in the interlayer space.

In conclusion, the invention changes the liquid outlet mode of the existing product, makes up the defects in the prior art, has novel and unique design and skillful structure, is convenient for popularization and application, and has good social and economic benefits.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic sectional view of an lng tank for vehicles according to the present invention;

FIG. 2 is a schematic cross-sectional view of the front end support assembly of the present invention;

FIG. 3 is a left side view of the front end supporting device of the present invention;

FIG. 4 is a schematic cross-sectional view of the rear end support device of the inner container of the present invention;

fig. 5 is a schematic sectional view of the rear end supporting device of the outer container of the present invention.

Detailed Description

The above and further features and advantages of the present invention are described in more detail below with reference to the accompanying drawings.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description of the present invention, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

As shown in fig. 1, the vehicle liquefied natural gas cylinder provided by the invention comprises a housing 1 and a liner 2, wherein a heat insulation space 3 is formed between the housing 1 and the liner 2, the front end of the liner is connected to the housing through a front end supporting device 21, and the rear end of the liner is connected to the housing through a liner rear end supporting device 22 and an outer liner rear end supporting device 12, the front end supporting device 21 is a rigid support, and the liner rear end supporting device 22 and the outer liner rear end supporting device 12 are soft supports; the inner container 2 is made of aluminum alloy, and the shell 1 is made of stainless steel. Because the existing stainless steel inner container is replaced by the aluminum alloy inner container, the weight of the natural gas cylinder is greatly reduced.

Referring to fig. 1, 2 and 3, in this embodiment, the front end and the rear end of the inner container 2 are respectively provided with an inner front end socket 211 and an inner rear end socket 221, the front end and the rear end of the outer shell 1 are respectively provided with an outer front end socket and an outer rear end socket 121, the front end supporting device 21 includes a first sealing plate 213, a second sealing plate 214, a pipeline distributing head 215, a rivet 216, a supporting small pipe 217, a supporting middle pipe 218, a neck cover 219, a sandwich pipeline 2110, a double-sided joint 2111, a third sealing plate 2112 and a fourth sealing plate 2113; the inner front end socket 211, the first closing plate 213, the support cylinder 212 and the third closing plate 2112 are all made of aluminum alloy, and the closing plate 214, the pipeline distribution head 215, the rivet 216, the support small pipe 217, the support middle pipe 218, the neck cover 219, the interlayer pipeline 2110, the double-sided connector 2111 and the fourth closing plate 2113 are all made of stainless steel; the inner front end socket 211 is provided with a support mounting hole, and the first sealing plate 213 is welded on the inner front end socket 211 to seal the support mounting hole; one end of the supporting cylinder 212 is welded with the first sealing plate 213, and the other end is welded with the third sealing plate 2112; after the first and

second cover plates

213 and 214 are brazed, the first and

second cover plates

213 and 214 are then reinforced with rivets 216, more specifically, a plurality of rivets 216, preferably 4 to 6 rivets, are uniformly distributed around the circumference of the support mounting hole. Compared with aluminum alloy, stainless steel has low thermal conductivity and high strength, so that the stainless steel is used on a supporting structure, but the brazing structure between the stainless steel and the aluminum alloy is too low in strength and cannot be used, and therefore the first sealing plate 213 and the second sealing plate 214 are connected in a locking rivet mode. The lock rivet structure can reliably connect stainless steel and aluminum alloy, can realize a liquefied natural gas cylinder for a vehicle with a new structure of an aluminum alloy inner container 2 and a stainless steel shell 1, and realizes light weight of the gas cylinder; the front end supporting device 21 is used for decomposing partial stress of a welding seam by using the rivet 216, so that the strength and reliability of the gas cylinder front end supporting device 21 can be improved, and the risk of air cylinder distortion caused by failure of the welding seam is reduced in the vibration process; front end strutting arrangement 21 radially can bear vibration load, transversely can bear impact load, and lock rivets structural strength height, and evenly distributed's 4 ~ 6 rivets 216 atress is even, and front end strutting arrangement 21 intensity and reliability improve greatly.

In a more specific embodiment, a fourth seal plate 2113 is welded to the outside of the third seal plate 2112. One end of the supporting middle tube 218 passes through the first sealing plate 213 and the second sealing plate 214 and is fixedly connected with the first sealing plate and the second sealing plate 214, the other end of the supporting middle tube 218 is positioned in the supporting cylinder 212, the supporting small tubes 217 are sleeved in the supporting middle tube 218, one end of the supporting small tube passes through the second sealing plate 214 and is connected with the pipeline distribution head 215, and the pipeline distribution head 215 passes through the shell 1 and is fixedly connected with the shell. A neck cover 219 is secured to the end of the support central tube 218 remote from the first closure plate 213 to close the rear end of the support central tube 218. The end of the pipe distribution head 215 connected to the support tube 217 is connected to a sandwich pipe 2110, and the sandwich pipe 2110 penetrates through the support tube 217 and extends into the support cylinder 212 to be connected to the double-sided connector 2111 in the fourth sealing plate 2113. Above-mentioned front end bearing structure can reduce the gas cylinder heat leakage under the prerequisite of guaranteeing front end strutting arrangement 21 intensity, reduces the static evaporation rate of gas cylinder, improves the wholeness ability of gas cylinder, saves the carminative loss of stewing for the customer. The front end supporting device 21 can solve the problem of connection between the stainless steel shell 1 and the aluminum alloy inner container 2, has strong reliability and can effectively reduce heat leakage.

As shown in fig. 1, 4 and 5, the inner container rear end supporting device 22 includes an inner rear end enclosure reinforcing plate 224, a rear end supporting shaft 225 and a rear end supporting small end enclosure 226, and the rear end supporting small end enclosure 226 and the inner rear end enclosure reinforcing plate 224 are respectively fixed on the inner side and the outer side of the inner rear end enclosure 221; the outer liner rear end supporting device 12 comprises a rear end supporting plate 122 and a shaft sleeve 124, the rear end supporting plate 122 is connected to the inner surface of the outer rear end enclosure 121, the shaft sleeve 124 is fixed on the rear end supporting plate 122, and more preferably, the shaft sleeve 124 and the rear end supporting plate 122 are connected with a reinforcing plate 123 to reinforce the connection strength of the shaft sleeve 124 and the rear end supporting plate 122; one end of the rear end support shaft 225 is sequentially and fixedly arranged on the inner rear end enclosure reinforcing plate 224, the inner rear end enclosure 221 and the rear end support small end enclosure 226, and the other end of the rear end support shaft passes through the shaft sleeve 124. The support tube 217 is collinear with the central axis of the rear support shaft 225. The inner rear end socket 221, the inner rear end socket reinforcing plate 224, the rear end support shaft 225 and the rear end support small end socket 226 are all made of aluminum alloy, and the outer rear end socket 121, the rear end support plate 122, the reinforcing plate 123 and the shaft sleeve 124 are all made of stainless steel; all aluminum alloy parts of the rear supporting device 24 are fixed together in a brazing welding mode; all stainless steel parts of the rear supporting device 13 are fixed together by argon arc welding. The inner container rear end supporting device 22 is made of aluminum alloy materials, so that the quality of the gas cylinder can be effectively reduced; the supporting device 12 at the rear end of the outer container is made of stainless steel, so that the heat conduction of the gas cylinder can be effectively reduced, and the static evaporation rate of the gas cylinder is reduced.

In a more preferred embodiment, the rear end support shaft 225 of the inner container rear end support device 22 and the outer container rear end support device 12 is in clearance fit with the shaft sleeve 124, so that the stretching and the shrinking of the front end support device 21 under the conditions of thermal expansion and cold contraction of the gas cylinder inner container 2 can be effectively avoided, and the risk of failure of the front end support device 21 is reduced.

In another embodiment, an excessive filling prevention device is arranged inside the inner rear end enclosure 221, the excessive filling prevention device comprises an excessive cylinder body 222 and an excessive end enclosure 223, the rear end of the excessive cylinder body 222 is connected with the excessive end enclosure, the front end of the excessive cylinder body is connected with the inner side of the inner rear end enclosure 221, so as to form a closed cavity, and a small hole 223a communicated with the inner cavity of the liner 2 is formed in the excessive end enclosure 223 or the excessive cylinder body 222. The volume of the excessive filling prevention device consisting of the excessive sealing head 223 and the excessive cylinder 222 is 8 percent of the total volume of the gas cylinder. When the gas cylinder is full of liquid, most of gas still exists in the excessive filling prevention device, and after the liquid filling is stopped, the liquid in the gas cylinder flows into the excessive filling prevention device until the liquid is balanced, so that certain gas exists above the liner and the excessive filling prevention device, the overflow of the gas cylinder after the filling is finished is prevented, and the effects of safe use and no damage to the pressurizing storage time of the gas cylinder are achieved.

In another embodiment, the inner front head 211 and the inner rear head 221 are both provided with molecular sieves, and the outer rear head 121 is provided with palladium oxide. The molecular sieve is used for adsorbing high molecular particles such as water, methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide and the like during vacuum pumping, so that the vacuum degree of the heat insulation space is ensured. The palladium oxide can adsorb residual toxic gas in the interlayer space.

The foregoing is merely a preferred embodiment of this invention, which is intended to be illustrative, and not limiting. The structure, the connection mode and the like of all the components in the invention can be changed, and the equivalent transformation and the improvement on the basis of the technical scheme of the invention are not excluded from the protection scope of the invention.

Claims

1. A liquefied natural gas cylinder for a vehicle comprises a shell (1) and an inner container (2), wherein a heat insulation space (3) is formed between the shell (1) and the inner container (2), the front end of the inner container is connected to the shell through a front end supporting device (21) and the rear end of the inner container is connected to the shell through an inner container rear end supporting device (22) and an outer container rear end supporting device (12), the front end supporting device (21) is a rigid support, and the inner container rear end supporting device (22) and the outer container rear end supporting device (12) are soft supports; the novel solar water heater is characterized in that the inner container (2) is made of aluminum alloy, the shell (1) is made of stainless steel, an inner front sealing head (211) and an inner rear sealing head (221) are arranged at the front end and the rear end of the inner container (2) respectively, and an outer front sealing head and an outer rear sealing head (121) are arranged at the front end and the rear end of the shell (1) respectively.

2. The liquefied natural gas cylinder for vehicle according to claim 1, wherein the front end supporting device (21) comprises a first closing plate (213), a second closing plate (214), a small supporting tube (217), a middle supporting tube (218), a supporting cylinder (212) and a pipeline distribution head (215), the inner front end sealing head (211) is provided with a supporting installation hole, the first closing plate (213) closes the supporting installation hole and is fixedly connected with the inner front end sealing head (211), the second closing plate (214) is welded on the outer side of the first closing plate (213), the first closing plate (213) and the second closing plate (214) are reinforced by a rivet (216), the inner side of the first closing plate (213) is fixedly connected with one end of the supporting cylinder (212), one end of the middle supporting tube (218) passes through the first closing plate (213) and the second closing plate (214) and is fixedly connected with the same, and the other end is located in the supporting cylinder (212), the supporting small pipe (217) is sleeved in the supporting middle pipe (218), and one end of the supporting small pipe protrudes out of the second sealing plate (214) and is connected with a pipeline distribution head (215).

3. The liquefied natural gas cylinder for vehicle according to claim 2, wherein the inner front head (211), the first sealing plate (213), and the support cylinder (212) are made of aluminum alloy, and the second sealing plate (214), the pipe distribution head (215), the rivet (216), the support tube (217), and the support middle tube (218) are made of stainless steel.

4. The liquefied natural gas cylinder for vehicle according to claim 3, wherein the front end supporting device (21) further comprises a neck cover (219), a third sealing plate (2112) and a fourth sealing plate (2113), the third sealing plate (2112) and the fourth sealing plate (2113) are sequentially fixed to one end of the supporting cylinder (212) away from the first sealing plate (213), and the neck cover (219) is fixed to one end of the supporting middle tube (218) away from the first sealing plate (213); the third sealing plate (2112) is made of aluminum alloy, and the neck cover (219) and the fourth sealing plate (2113) are made of stainless steel.

5. The liquefied natural gas cylinder for vehicles as claimed in any one of claims 1 to 4, wherein the liner rear end support device (22) comprises an inner rear head reinforcement plate (224), a rear end support shaft (225) and a rear end support small head (226), the rear end support small head (226) and the inner rear head reinforcement plate (224) are respectively fixed to the inner side and the outer side of the inner rear head (221); the outer liner rear end supporting device (12) comprises a rear end supporting plate (122) and a shaft sleeve (124), the rear end supporting plate (122) is connected to the inner surface of the outer rear end sealing head (121), and the shaft sleeve (124) is fixed on the rear end supporting plate (122); one end of the rear end support shaft (225) is sequentially and fixedly arranged on the inner rear end enclosure reinforcing plate (224), the inner rear end enclosure (221) and the rear end support small end enclosure (226), and the other end of the rear end support shaft penetrates through the shaft sleeve (124).

6. A vehicle LNG cylinder as claimed in claim 5, characterized in that the rear support shaft (225) is a clearance fit with the sleeve (124).

7. The liquefied natural gas cylinder for vehicle according to claim 5, wherein the inner rear head (221), the inner rear head reinforcing plate (224), the rear end support shaft (225) and the rear end support small head (226) are all made of aluminum alloy, and the outer rear head (121), the rear end support plate (122) and the shaft sleeve (124) are all made of stainless steel.

8. The liquefied natural gas cylinder for vehicle as claimed in claim 5, wherein the inner side of the inner rear end cap (221) is provided with an anti-overfilling device, the anti-overfilling device comprises an anti-overfilling cylinder (222) and an anti-overfilling end cap (223), the rear end of the anti-overfilling cylinder (222) is connected with the anti-overfilling end cap, the front end of the anti-overfilling cylinder is connected with the inner side of the inner rear end cap (221), so as to form a closed cavity, and the anti-overfilling end cap (223) or the anti-overfilling cylinder (222) is provided with a small hole (223a) communicated with the inner cavity of the inner container (2).

9. A vehicle liquefied natural gas cylinder according to claim 7, wherein said overfill prevention device has a volume of 8% of the total cylinder volume.

10. The liquefied natural gas cylinder for vehicle as claimed in claim 1, wherein the inner front head (211) and the inner rear head (221) are provided with molecular sieves, and the outer rear head (121) is provided with palladium oxide.