CN110538923B

CN110538923B - Method for deep drawing aluminum inner container of pressure container

Info

Publication number: CN110538923B
Application number: CN201910913038.0A
Authority: CN
Inventors: 冯存江; 李世洪; 凌建; 李明; 战玉勋; 张云津
Original assignee: Sinoma Science & Technology Chengdu Co ltd
Current assignee: Sinoma Science & Technology Chengdu Co ltd
Priority date: 2019-09-25
Filing date: 2019-09-25
Publication date: 2021-09-03
Anticipated expiration: 2039-09-25
Also published as: CN110538923A

Abstract

The invention discloses a method for deep drawing an aluminum inner container of a pressure container, which relates to the technical field of aluminum inner container processing, is derived from the research on high-reinforcement risk prevention and control key technology of steel materials of vehicle-mounted CNG gas cylinders in the project of China department of science and technology, and comprises the following steps of: adjusting each ring die in the sizing die, and adjusting and aligning the sizing die and the first punch through adjusting the fixed seat and the positioning ring to enable the sizing die and the punch to be coaxial; placing the blank on a female die, impacting the blank by a punch, and carrying the blank to pass through each layer of ring die; multiple drawing processes can be continuously carried out on the same equipment. The invention provides a production process for manufacturing a pressure container by using an aluminum plate. Compared with a tube-made bottle, the bottle can produce a single-end bottle, and has stable performance and high efficiency.

Description

Method for deep drawing aluminum inner container of pressure container

Technical Field

The invention relates to the technical field of aluminum inner container processing, in particular to a method for deep drawing an aluminum inner container of a pressure container.

Background

With the continuous search for clean energy, fuel cells are becoming a new option, especially hydrogen fuel cells. A fuel cell generally contains a pressure vessel with a combustible gas, and supplies electric energy by burning the combustible gas. Therefore, the ability of the pressure vessel to contain a combustible gas is directly related to the range of the fuel cell.

The pressure containers commonly used at present generally comprise an aluminum inner container and a steel inner container. The aluminum inner container is made of aluminum materials, and the steel inner container is made of steel materials. Compared with a steel liner, the aluminum liner is lighter and has higher pressure bearing capacity, and the more combustible gas is contained, so that the aluminum liner becomes the choice of more and more pressure containers.

The existing aluminum inner container is usually made into a cylinder structure by a drawing die. The existing deep drawing die comprises a punch and a sizing die, the sizing die is only of a cylindrical structure with the same diameter, and the aluminum inner container formed by deep drawing has a fixed diameter of a main body part and cannot be lighter and thinner. More importantly, the existing deep drawing die is adopted, and the final forming requirement can be met only by discontinuously and repeatedly deep drawing, so that the operation is very troublesome.

Disclosure of Invention

The invention aims to provide a method for drawing an aluminum inner container of a pressure container, which aims to solve the problem that the existing drawing method cannot continuously thin the wall of the inner container.

The method for deep drawing the aluminum inner container of the pressure container comprises the following steps: adjusting each ring die in the shaping die; adjusting the alignment sizing die and the first punch through adjusting the fixed seat and the positioning ring to enable the sizing die and the punch to be coaxial; and placing the blank on the female die, and impacting the blank by the punch to carry the blank to pass through the ring dies of each layer.

The scheme has the advantages that:

compared with the existing drawing method, the drawing is continuously carried out twice, the inner ring of the blank holder die of the first drawing is the female die of the second drawing, and after the first drawing is finished, the second drawing can be directly carried out without detaching the die, so that the aluminum inner container can be further thinned after the drawing of the gas cylinder inner container is finished by the drawing die.

In addition, the aluminum inner container of the pressure container is processed by a deep drawing method, the wall thickness of the cylinder body of the inner container is uniform on the circumference, and the difference of the wall thickness is very small in the longitudinal direction; the deep drawing forming has uniform circumferential wall thickness and small longitudinal deviation, is favorable for improving the fatigue performance of the gas cylinder and ensures that the gas cylinder is safer; the smooth transition of the joint of the end socket and the cylinder body can be controlled by drawing forming, so that stress concentration is avoided, and the service life is prolonged; the seal structure at one end of the deep drawing formed bottom can be completely realized according to the design, thereby being beneficial to controlling the quality and ensuring that the bottom of the gas cylinder is not leaked; the quality of the deep-drawing formed product is high and basically consistent, and the quality is easy to control.

The invention provides a production process for manufacturing a pressure container by using an aluminum plate. Compared with a tube-made bottle, the bottle can produce a single-end bottle, and has stable performance and high efficiency.

Further, the ring die in the shaping die at least comprises an edge pressing die, a female die and a thinning ring which are sequentially connected from top to bottom; during drawing, the first punch strikes the blank through the edge pressing die and the female die to form a cup-shaped semi-finished product with consistent wall thickness, and then the wall thickness of the cup-shaped semi-finished product is thinned through the thinning ring to form a disposable cup-shaped body.

When the first punch punches and strikes the blank from top to bottom, and passes through the edge pressing die and the female die, one half of the diameter difference value of the first punch and the female die is the wall thickness of the formed semi-finished cup-shaped body, the wall thickness is uniform at the moment, and when the first punch continues to strike and strike the semi-finished cup-shaped body downwards through the thinning ring, the wall thickness of the semi-finished cup-shaped body is further thinned to form the primary cup-shaped body.

Furthermore, the shape of the working surface of the inner ring of the female die is matched with the shape of the bottom end of the first punch, and the bottom of the cup-shaped body is formed by punching the female die and the first punch during drawing.

The top end of the die and the bottom end of the first punch have matched R angles, and the R angles are determined according to the plate thickness, the drawing times and the specific shape of the workpiece. The shapes of the two are matched, and the two are drawn together to form the bottom of the closed end of the cup-shaped body, namely the bottom end enclosure of the aluminum inner container of the pressure container after molding.

Further, the second punch is arranged below the base; the shape of the bottom end of the edge pressing die is matched with the shape of the top end of the second punch; and after the primary cup-shaped body is formed, stopping the first punch, starting the second punch, and punching the primary cup-shaped body by the second punch and the bottom end of the blank pressing die to form a secondary cup-shaped body.

And the bottom end of the edge pressing die is used as another punch in a second drawing process to be matched with the second punch to perform second process drawing on the primary cup-shaped body to form a secondary cup-shaped body, and the shapes of the second punch and the bottom end of the edge pressing die determine the shape of the bottom end of the secondary cup-shaped body, namely the shape of the inner surface of the bottom end socket of the formed liner.

Further, after drawing is finished, the punch returns, and a workpiece is directly taken out from the lower surface of the base.

After the first drawing is finished, the next drawing is directly carried out without disassembling a die or taking out a workpiece, and the material can be automatically returned after the next drawing is carried out, so that the workpiece is separated from the punch, and the workpiece is conveniently taken out.

Further, the positions of the first punch and the fixed seat are adjusted by adjusting the fixed seat and a plurality of positioning pins on the first punch in the radial direction.

The fixing seat is fixedly connected with the punching machine, the axial position of the first punch is fixed relative to the punching machine through a ceramic fixing pin, and the position of the first punch is prevented from changing when the first punch is punched in a punching mode.

Furthermore, an annular mounting groove for positioning is arranged on the base, a raised positioning ring matched with the base mounting groove is arranged on the ring die at the bottommost layer, and the raised positioning ring and the base mounting groove are matched for positioning.

Through these positioning mechanism of holding ring and fixing base, can effectively guarantee that the relative position in stamping process is accurate, and then guarantee the precision of wall thickness processing.

Further, the first punch performs press drawing at a speed of 25 to 40 mm per second.

Drawing at this speed can maximize the drawing effect.

Furthermore, the surface lubrication mode adopted during drawing is to coat drawing oil.

Drawings

Fig. 1 is a schematic structural diagram of a drawing die according to an embodiment of the present invention.

Detailed Description

The following is further detailed by way of specific embodiments:

example one

The drawing die for drawing in this embodiment includes, as shown in fig. 1, a first punch 10 and a sizing die arranged from top to bottom. Wherein, the top of first drift 10 is connected with the punching machine through fixing base 11, starts the punching machine, and first drift 10 does the up-and-down motion. The shaping mold comprises at least three ring molds, the number of the ring molds in the embodiment is three, and the three ring molds are respectively an edge pressing mold 21, a female mold 22 and a thinning ring 23 which are coaxially arranged from top to bottom. The diameter of each ring die, the diameter of the thinning ring 23 is the smallest.

As shown in fig. 1, first drift 10 is connected with the punching machine through fixing base 11, and fixing base 11 cover is outside first drift 10, through a plurality of locating pins, passes fixing base 11 and first drift 10, and fixing base 11 is integrative with the punching machine, through fixing base 11, makes first drift 10 for the rigidity of punching machine, avoids first drift 10 to appear the condition that the position rocked when moving from top to bottom.

The shape of the bottom end of the first punch 10 is matched with the shape of the top end of the female die 22, the bottom end of the first punch 10 and the top end of the female die 22 are provided with matched R angles, and the bottom shape of the cup-shaped body, namely the shape of the bottom end enclosure part of the formed liner, is determined together. The difference between the diameter of the first punch 10 and the diameter of the die 22 divided by two is the wall thickness of the cup when the first drawing is not reduced.

The inner diameter of the thinning ring 23 is smaller than that of the female die 22, and when the first punch 10 carries the cup-shaped body to continue punching downwards, the thinning ring 23 further thins the wall thickness of the formed cup-shaped body.

A base 40 is installed at the lower end of all the ring dies, and a positioning ring 30 for fixing the position of the ring die is integrally formed between the base 40 and the ring die (the thinning ring 23 in the embodiment) at the lowest layer.

As shown in fig. 1, the top end of the base 40 is provided with a circular groove. The inner side surface of the circular groove is provided with a plurality of mounting grooves, the circumferential surface of the positioning ring 30 is outwards integrally formed with a plurality of bulges matched with the mounting grooves, and the positioning ring 30 and the base 40 are relatively fixed through the mounting grooves and the bulges. Meanwhile, the top end of the positioning ring 30 is annularly provided with bolt holes for connecting with the bottom end of the thinning ring 23. The thinning ring 23 and the positioning ring 30 are connected by bolts. In this way, the position of the thinned loop 23 and the other loop dies can be fixed relative to the base 40. The position of the base 40 is fixed relative to the punching machine, the punching machine and the first punch 10 are fixed relative to the punching machine through the fixing seat 11, the first punch 10 is fixed relative to the punching machine, the position of the first punch 10 and the position of the whole stock mold are fixed relative to each other, the situation of dislocation is avoided when punching is carried out, and the wall thickness of a product formed by deep drawing can be accurately controlled.

The top surface of the female die 22 is provided with a placing groove for placing the blank.

In this embodiment, the base 40 is made of steel.

Compare stock mould in current deep-drawing mould and be a whole, the diameter size of each part can't be adjusted, the thickness of the gas cylinder inner bag of hardly further attenuate, the deep-drawing mould of structure more than this embodiment can rationally allocate the diameter size of each position circle mould, and then adjusts the thickness of each position of aluminium system inner bag, accomplishes the purpose of attenuate aluminium system inner bag as far as possible.

When the gas cylinder is drawn by using the drawing die in the embodiment, the position of the ring die is first adjusted as required, the positioning ring 30 is connected with the ring die (the thinning ring 23 in the embodiment) at the bottommost position, and all the ring dies and the positioning ring 30 are connected into a seamless shaping die. The round blanks are then placed in the placement tray. A punch connected to the first punch 10 is activated to enable the first punch 10 to strike the blank regularly down through the layers of the ring die. In this embodiment, the first punch 10 strikes the blank downwards at a speed of 25 to 40 mm per second, and the first punch 10 punches the blank at a constant speed, which is beneficial to the gradual drawing and extension of the blank.

The stamping is stopped until the bottom cylindrical structure formed by the blank striking extends out of the top ring die (the blank pressing die 21 in the embodiment). After the primary stretching, the next step of drawing can be directly carried out without disassembly until the drawing process is finished, then the connection between the positioning ring 30 and the ring die (the thinning ring 23 in the embodiment) at the bottommost position is disconnected, and the formed cylinder structure with the bottom is taken out to form a processing semi-finished product of the aluminum inner container. And then, further thinning the semi-finished product on a strong spinning machine, and closing the opening end on a closing-in machine to form a liner bottle mouth, namely finishing the integral processing of the liner. The processing steps after drawing can be carried out by adopting the prior art, and are not described again.

In the aluminum inner container drawn by the drawing method of the present embodiment, after the inner container tube is drawn, the front section is as thick as the middle section, and the rear section is relatively thick. The wall thickness of the rear end and the thickness of the bottom end socket are in good transition, so that stress concentration caused by shape mutation is avoided. The wall thickness through control anterior segment and middle section reaches the purpose of the whole inner bag thickness of attenuate, makes the aluminium system inner bag that processing formed lighter more, and in subsequent processing, through the attenuate middle section of rotating by force, makes whole inner bag lightweight more.

Example two

In this embodiment, a second punch is mounted in the base 40 and can be extended upward and moved up and down, and the second punch is located in the entire shaping mold. The shape of the top end of the second punch matches the shape of the bottom end of the blank holder 21, both having matching R-angles, determining the shape of the inner surface of the cup to be machined by the shape of the second punch and the blank holder 21. When the first punch 10 punches the formed cup-shaped body into a certain shape, the first punch 10 is moved upwards to separate from the sizing die, the second punch is started to move upwards, at this time, the inner surface of the bottom end of the edge pressing die 21 becomes a female die for secondary drawing, and simultaneously plays a role of the edge pressing die for secondary drawing, and the cup-shaped body moves upwards along the inner surface of the edge pressing die 21 under the action of the second punch. The bottom end of the trimming die 21 becomes the bottom end of the first punch 10, and during the upward movement of the cup-shaped body pushed by the second punch, the bottom end of the trimming die 21 comes into contact with the inner surface of the cup-shaped body, and the trimming die 21 and the second punch perform the second drawing operation on the cup-shaped body together. Through the first punch 10 and the built-in second punch, two drawing process operations of the blank can be finished at one time without replacing a machine, the operation is simple, and the wall thickness of the formed cup-shaped body and the inner container formed later can be accurately controlled due to the arrangement of the positioning structures such as the fixed seat 11, the positioning ring 30 and the like.

EXAMPLE III

In this example, when the bottle for a vehicle was drawn, the punching operation was performed while keeping the first punch at a temperature of 80 to 120 ℃. Meanwhile, annealing operation is carried out between each drawing process, work hardening of the workpiece is eliminated, and stress is eliminated.

After the first punch 10 finishes the drawing of the first process, the female die 22 or the thinning ring 23 is disassembled, the primarily formed cup-shaped body is taken out for annealing, then the primarily formed cup-shaped body is put into a sizing die, the taken-out female die 22 or the thinning ring 23 is installed, and the second punch is started for drawing of the second process. And after the second process drawing is finished, taking out the secondarily formed cup-shaped body for annealing, then putting the secondarily formed cup-shaped body into another punching machine with a larger punch head running length, and after the third process drawing is carried out on another sizing die with a larger number of ring dies, finishing the whole drawing operation.

Example four

In the embodiment, along the axial direction of the ring die, the inner hole of the ring die is provided with a lubricating belt, a compression belt, a sizing belt and an outlet belt, adjacent belts are in transition by using a fillet, and a generatrix of the sizing belt is a curve (such as an elliptic curve, a parabolic curve, a hyperbolic curve or other curves); the smallest inner diameter of the ring die is located on the bearing. In the drawing process, when passing through a ring die, metal passes through a fillet from a compression belt and then enters a sizing belt with a curved bus, and the transition form is more in line with the principle of smooth transition of a metal flow curve; the smooth transition mode reduces the friction between the metal and the surface of the bearing, thereby reducing the drawing force, improving the pass processing rate and the production efficiency and prolonging the service life of the die.

EXAMPLE five

When the ring dies are connected, the connecting pieces are inserted into the through holes in the wall of the ring die, so that the adjacent ring dies are connected, and the rubber pads in the ring dies are connected with each other.

The ring die is provided with a wall with a cylindrical structure, and a through hole for connecting the connecting piece is formed in the wall along the axial direction. The circumference of the through hole is embedded with a shaft sleeve for heat preservation, and the shaft sleeve is connected with a rubber pad embedded in the wall.

The connecting piece makes the rubber pad of inlaying in the circle mould also connect into a unified whole through the connecting piece when connecting two circle moulds, and the axle sleeve also generally adopts rubber to make, and the axle sleeve has played spacing and connected rubber pad's effect. The rubber gasket is embedded in the ring die, so that the whole shaping die has a certain heat preservation effect, and the heated blank can be drawn at the temperature as long as possible.

The descriptions in the above embodiments and the like can be used to explain the contents of the claims.

Claims

1. The deep drawing method of the aluminum inner container of the pressure container is characterized by comprising the following steps of: adjusting each ring die in the shaping die; connecting the positioning ring with the thinning ring at the bottommost end position, and connecting all ring dies and the positioning ring into a seamless shaping die; the ring mold in the shaping mold at least comprises an edge pressing mold, a female mold and a thinning ring which are sequentially connected from top to bottom; the shape of the bottom end of the first punch head is matched with that of the top end of the female die, and the first punch head and the female die have matched R angles; the inner diameter of the thinning ring is smaller than that of the female die; adjusting the alignment sizing die and the first punch through adjusting the fixed seat and the positioning ring to enable the sizing die and the punch to be coaxial; placing a blank on a female die, wherein a placing groove for placing the blank is formed in the top surface of the female die, and the blank is a round blank; the punch impacts the blank and passes through the ring dies of each layer together with the blank;

adjusting the positions of the first punch and the fixed seat by adjusting the fixed seat and a plurality of positioning pins on the first punch in the radial direction; the first punch carries out stamping drawing at the speed of 25-40 mm per second;

during deep drawing, a first punch firstly strikes a blank through a side pressing die and a female die to form a cup-shaped semi-finished product with consistent wall thickness, and then the wall thickness of the cup-shaped semi-finished product is thinned through a thinning ring to form a primary cup-shaped body;

the second punch is arranged below the base; the shape of the bottom end of the edge pressing die is matched with the shape of the top end of the second punch; and after the primary cup-shaped body is formed, stopping the first punch, starting the second punch, and punching the primary cup-shaped body by the second punch and the bottom end of the blank pressing die to form a secondary cup-shaped body.

2. The method for deep drawing of aluminum inner container of pressure vessel as claimed in claim 1, wherein the shape of the working surface of the inner ring of the female die is matched with the shape of the bottom end of the first punch, and the bottom of the cup-shaped body is formed by punching of the female die and the first punch during deep drawing.

3. The method for deep drawing of the aluminum inner container of the pressure vessel as claimed in claim 1, wherein the punch is withdrawn after the deep drawing is completed, and the workpiece is taken out directly under the base.

4. The method for deep drawing of aluminum inner container of pressure vessel as claimed in claim 1, wherein the base is provided with an annular mounting groove for positioning, the ring die at the bottom layer is provided with a raised positioning ring matched with the mounting groove of the base, and the two are matched for positioning.

5. The method for deep drawing of aluminum inner container of pressure vessel as claimed in claim 1, wherein the surface lubrication method adopted during deep drawing is to apply drawing oil.