JP5016174B2 - Hydroforming flushing system - Google Patents

Description

[0001]
(Field of the Invention)
The present invention relates to a system for flushing a hydroformed part to remove debris from the inside of the hydroformed part.
[0002]
BACKGROUND OF THE INVENTION
In recent years, hydroforming technology has become increasingly important in the manufacturing industry, especially in the automotive industry. In some hydroforming, a metallic tubular blank (usually steel) is placed in the die cavity. A pair of hydraulic rims (hydraulic frame or hydraulic ram) having a central port seal both ends of the tubular blank and inject pressurized fluid through the port into the tubular blank. The pressurized fluid causes the tubular blank to expand and conform to the surface defining the cavity. By such hydroforming, high strength parts can be processed into complex tubular shapes that cannot be made by other practical and economical methods. Such hydroforming is described in U.S. Pat. Nos. 4,567,743, 5,070,717, 5,107,693, and 5,233,854. No. 5,239,852, No. 5,333,755, and No. 5,339,667.
[0003]
In more advanced hydroforming, the thickness of the tube is maintained within a predetermined range during the expansion process so that when the tube is expanded, the hydraulic frame is pushed inward toward each other to form a metal flow within the tube.
[0004]
Such hydroforming processes are described in US Pat. Nos. 5,718,048, 5,855,394, 5,899,498, 5,979,201, No. 5,987,950.
[0005]
In some applications, it is required to produce a finished product having a plurality of holes that are used to attach other components. For example, it is known in the automotive industry to hydroform tubular blanks to form an engine cradle for use in mounting an automobile engine. The completed tubular part must have a hole through which a fastener is inserted for attachment to an engine mounting bracket or the like. In order to facilitate the formation of holes in these parts, it is known to perform a drilling operation with a hydroforming die. Typically, a hole is punched into the tube while applying pressure. In one method, a portion of a punched tube (called "slag") has an edge portion that remains connected to the tube and hangs down in the tube. This is a problem because it adds unnecessary weight to the part, which is always a concern in the automotive industry. In another method, after forming the hole, the punch is withdrawn from the tube, and the portion formed by the punch is maintained in engagement with the punch by the force of fluid pressure when the punch is withdrawn from the tube. The The slag is then flowed to the waste collector with fluid. Such a typical operation is disclosed in US Pat. No. 5,816,089. One problem with the techniques described above is that the slag may not fit exactly with the hole that comes out when it is pulled out and may fall into the tube. This slag must be recovered by other means.
[0006]
[Summary of the Invention]
The object of the present invention relates to a system capable of removing debris from the inside of a hydroformed part.
[0007]
Accordingly, the present invention provides a hydroforming assembly comprising a plurality of die structures that can be attached to a press so as to reciprocate between an open state and a closed state. The die structure includes a cooperating die surface that forms a die cavity when in the closed state and receives a metal tubular blank when in the open state. A hydroforming fluid supply system includes a tube end engagement structure that is movable to selectively and sealingly engage both ends of a tubular blank. A hydroforming fluid supply system supplies pressurized fluid to the inside of the tubular blank to expand the tubular blank outwardly in alignment with the die cavity. A punch extends in at least one passage of the die structure. The punch is movable between a retracted state and an extended state. A punch drive assembly moves the punch between the retracted state and the extended state to punch holes in the expanded tubular blank. A flushing system communicates with the die cavity and causes a flushing fluid stream to flow inside the tubular blank.
[0008]
In accordance with another aspect of the present invention, a method is provided for forming holes in a hydroformed metal tubular blank and removing punched debris from the metal tubular blank. A plurality of die structures are prepared in the press so as to reciprocate between an open state and a closed state. The die structure includes cooperating die surfaces that form a die cavity when in the closed state. The die structure is opened. A metal tubular blank is placed in the die cavity. Close the die structure. The inside of the tubular blank is pressurized with a fluid such that the tubular blank is inflated with the die cavity to form an expanded tubular blank. A punch is passed through the expanded tubular blank so as to punch holes in the expanded tubular blank. The inside of the tubular blank is depressurized. Fluid is flowed through the expanded tubular blank such that the punched portion of the expanded tubular blank flows from the inside of the expanded tubular blank.
[0009]
Detailed Description of Preferred Embodiments
Referring to the drawings in detail, FIG. 1 shows a schematic cross-sectional view of a hydroforming apparatus of an embodiment of the present invention, generally designated by the reference numeral 10. The hydroforming apparatus 10 includes a hydroforming press generally indicated by numeral 12, and the hydroforming press includes an upper support structure 14, a lower support structure 16, and a vertical support structure 18. Yes. The hydroforming apparatus 10 includes a cooperating die structure, and the die structure includes an upper die structure 20 and a lower die structure 21. The upper die structure 20 can move up and down, and the die structures 20 and 21 can move between the open position and the closed position. FIG. 1 shows the die structures 20, 21 in the closed position. The dies 20, 21 provide a die surface 23 that forms a sealed die cavity 23 when the dies 20, 21 are in a closed position. The size and shape of the cavity 23 are set so as to form a desired shape and size of the component to be hydroformed. FIG. 1 shows a metal tubular blank 24 placed in a die cavity 23 for hydroforming. Both ends of the metal tubular blank 24 are sealed by a pair of hydraulic pipe end engaging bodies, that is, “hydraulic frames (hydraulic rims or hydraulic rims)” 25, and the hydraulic frames 25 are positioned at different positions by the hydraulic actuators 26. It is movable. Each frame 25 has a central port 27 through which very high pressure (eg, about 10,000 atm) hydroforming fluid is injected into the metal tubular blank 24.
[0010]
At least one of the die structures 20, 21 incorporates a reciprocating hydraulic punch assembly, generally designated 50 and shown in detail in FIG.
[0011]
The hydroforming apparatus 10 includes a flushing fluid system generally designated 30 and in communication with the die cavity 23. The flushing fluid system 30 (as shown in FIG. 4) is used to remove at least one portion or “slag” 86 punched from the expanded metal tube 24. The flushing fluid system 30 includes a flushing fluid inlet port 32 disposed at one end of the die cavity 23 and a flushing fluid outlet port 33 disposed at the opposite end of the die cavity 23. Both of these ports 32, 33 are preferably formed in the lower die structure 21, as shown. The flushing fluid system 30 preferably comprises a debris separator, indicated generally at 34 and comprising a mesh or screen 36. The flushing fluid system also preferably includes a fluid reservoir 38 that is used to store and / or recycle the flushing fluid, if necessary. The flushing fluid system 30 also preferably includes a connecting piping line 42 and a circulator 40 so that the flushing fluid can be circulated within the flushing fluid system 30.
[0012]
Referring to FIG. 3, the hydraulic perforation punch assembly 50 is shown in detail. A punch assembly 50 is used to punch holes 84 in the expanded metal tube 24 (as shown in FIG. 4). Several or similarly designed punch assemblies 50 may be attached to one or both of the die structures 20, 21. The punch assembly 50 includes a punch receiving passage 51, which is incorporated in the die structure, through which the punch 52 can move between a retracted position and an extended position. The punch 52 can slide in a sealing relationship with respect to the passage 51 by the action of the annular seal member 53 disposed therebetween. Punch assembly 50 includes a punch drive assembly, generally designated 54, that is used to drive punch 52 between a retracted position and an extended position. In the retracted position, the distal end face 55 of the punch 52 is flush with the die surface 22 and helps to form the die cavity 23. The punch drive assembly 54 includes a punch drive 56, which may be a hydraulic cylinder, which is connected to a punch piston. A proximal end 59 of the punch 52 is fixed to and connected to the punch piston 58. The punch piston 58 is movable between a retracted position and an extended position. The piston 52 moves through an opening 62 in the piston drive housing 60 in a slidable relationship with respect to the opening 52.
[0013]
The flushing fluid system 30 includes a slag removal system, generally designated 70, that provides a means for removing the slag from the working end face 55 of the punch 52. A slug removal fluid partition wall 72 is attached to at least one of the die structures 20 and 21. A peripheral seal 74 between the die structures 20, 21 and the septum 72 surrounds the slag removal system 70 so that the slag removal system 70 is sealed from the outside air and pressurized with the slag removal fluid. The slag removal system 70 includes a slag removal fluid inlet port 76 disposed in the slag removal fluid septum 72. The slag removal fluid inlet port 76 may be connected to a suitable high pressure pump so that pressurized slag removal fluid can be supplied to the slag removal system 70. The slag removal fluid inlet port 76 is connected to a slag removal fluid passage 78 that may be shared by the plurality of pump assemblies 50. The passage 78 is a suitably sized groove formed in the die structure 20, 21. The passage 78 communicates with a slag removal fluid pressure chamber 79 formed in the die structure 20, 21. The punch 52 includes a slag removing fluid port 80 that penetrates the punch 52 in the longitudinal direction. This slag removal fluid port 80 begins with a slag removal fluid inlet 82 located on the side of the punch 52 and ends with an outlet 83 on the punch working surface 55. The slag removal fluid inlet 82 is arranged to communicate with the slag removal fluid pressurization chamber 79 when the punch 52 is in the extended position so that the slag removal fluid port 80 can be pressurized with the slag removal fluid as desired. Yes.
[0014]
The operation of the hydroforming apparatus 10 will be described. Referring to FIG. 2, a metal tube 24 is expanded with hydroforming fluid pressure, aligned with the inner surface 22 of the die cavity 23, and engaged with the working surface 55 of the punch 52 in the retracted position. In order to maintain the wall thickness of the expanded metal tube 24 at a predetermined value, as the tube 24 is expanded, the hydraulic frames 25 are pushed inward toward each other to form a metal flow within the tube 24.
[0015]
In FIG. 4, the punch drive or cylinder 56 is activated to move the punch to the extended position. By this operation, after the metal tube 24 is expanded and aligned with the die surface 22, the punch 52 is moved from the retracted position to the extended position, punching the hole 84 through the expanded metal tube 24, and slag The punch 52 is pushed through the expanded metal tube 24 to form 86. The hydroforming fluid is maintained at a high pressure in the expanded metal tube 24 to support the tube 24 from the inside during the drilling operation and prevent the metal tube 24 expanded by the punch 52 in the region adjacent to the hole 84 from being deformed. Yes. The die structures 20 and 21 are held in the closed position, and the expanded metal tube 24 is held in a state of being engaged with the surface 22 of the cavity 23. In the extended position, the punch 52 acts to seal the hole 84 punched into the tube 23 and helps retain fluid in the tube 24 during the subsequent slag flushing process, and fluid from the tube 24 To prevent leakage.
[0016]
FIG. 5 shows the punch 52 in the extended position in detail. The slag removal fluid inlet 82 communicates with the slag removal fluid pressure chamber 79 and allows slag removal fluid to flow through the slag removal fluid port 80.
[0017]
Referring to FIG. 6, both frames are preferred, but at least one of the hydraulic frames 25, i.e., the frame adjacent to the port 33, is out of sealing engagement with the end of the expanded metal tube 24 and is within the tube 24. It is movable so as to reduce the pressure of the hydroforming fluid. The hydraulic frame 25 is positioned to facilitate flushing fluid flow and removal of the slag 86 from the tube 24. The die structures 20, 21 are maintained in a closed position, and a flushing fluid system 30 communicates with the die cavity 23 to flow flushing fluid into the expanded metal tube 24.
[0018]
Generally, the slug 86 remains engaged with the working end surface 55 of the punch 52. If so, the present invention provides various means for removing the slug 86 from the working end face 55 of the punch 52.
[0019]
In one embodiment, the slag 86 is forced out of the end face 55 of the punch 52 by pressurization of the slag removal system 70 that pushes fluid out of the fluid port 80 and pulls the slag away from the working surface 55 of the punch 52. Alternatively, the punch 52 may be quickly reciprocated using the punch driving device 56 to remove the slag 86 from the working surface 55 of the punch 52.
[0020]
In yet another embodiment, the slug 86 can be forcibly removed from the working end surface 55 of the punch 52 with only a fast flow of flushing fluid through the tube 24 when supplied by the flushing fluid system 30.
[0021]
The flushing fluid circulator 40 and the connecting piping line 42 provide flushing fluid at a flow rate sufficient to flow the separated metal slag 86 through the expansion metal tube 24 and remove the slag 86 from the tube 24. Flushing fluid enters from the inlet port 32, passes through the tube 24, carries the slug 86 through the opposite end of the tube 24, and carries out through the outlet port 33. The outlet port 33 and the connecting piping line 42 have dimensions sufficient to allow the flushing fluid and the slag 86 to flow out of the die 21 smoothly. As the slag 86 is metal removed from the die 21, it is separated from the flushing fluid by the mesh or screen 36 in the waste separator 34 and the fluid is collected in the fluid reservoir 38. During the flushing fluid operation, the punch 52 is maintained in the extended position to prevent leakage of flushing fluid from the punched hole 84 in the tube 24.
[0022]
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive of the invention, and as a preferred embodiment is shown and described; All changes and modifications within the scope described in the scope of are included in the protection scope.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a hydroforming apparatus having an in-die hydraulic drilling and slag removal system according to the principles of the present invention, a metal tubular blank inserted into the hydroforming apparatus for hydroforming. Is shown.
FIG. 2 is a view similar to FIG. 1, showing the expanded metal tube after hydroforming.
FIG. 3 is an enlarged view of a portion of the hydroforming apparatus of FIG. 2 showing details of the hydraulic perforation punch assembly with the punch in the retracted position.
FIG. 4 is a view similar to FIG. 1, showing the punch in the extended position after punching a hole in the expanded metal tube.
FIG. 5 is a partially enlarged view similar to FIG. 3, showing the punch in the extended position after punching a hole in the expanded metal tube.
6 is a view similar to FIG. 4, showing a state in which the punched slag is flowing from the expanded metal pipe. FIG.

Claims (16)

An assembly for hydroforming,
A plurality of die structures attachable to a press so as to reciprocate between an open state and a closed state, comprising a cooperating die surface that forms a die cavity when in the closed state; and A die structure for receiving a metal tubular blank when in a state;
A hydroforming fluid supply system, comprising a tube end engaging structure movable to selectively and sealingly engage both ends of the tubular blank, wherein the tubular blank is expanded outwardly to A hydroforming fluid supply system for supplying pressurized fluid to the inside of the tubular blank to expand into the die cavity;
A punch extending through at least one passage of the die structure and movable between a retracted state and an extended state;
A punch drive assembly coupled to the punch for moving the punch between the retracted state and the extended state, and punching a hole in the tubular blank after the tubular blank is expanded to the expanded state;
A flushing system communicating with the die cavity and supplying a flushing fluid flow into the tubular blank for flowing a portion of the tubular blank punched out by the punch drive assembly from within the tubular blank. Yes,
Hydroforming assembly characterized by the above. The punch has a working surface;
The working surface is flush with a die surface of the die cavity when the punch is in the retracted position and extends into the die cavity when in the extended position;
The hydroforming assembly according to claim 1. The punch has a fluid passage communicating with the working surface of the punch;
A fluid passage is in communication with a source of a second pressurized fluid discharged through the fluid passage and pushes the punched portion of the tubular blank from the working surface of the punch;
Hydroforming assembly as claimed in claim 2. The fluid passage communicates with a source of the second pressurized fluid when the punch is in the extended position;
The hydroforming assembly according to claim 3. The punch drive assembly includes a housing having an opening, the punch extending through the opening;
The hydroforming assembly according to claim 4. The inside of the housing is isolated from the source of the second pressurized fluid;
The fluid passage has an inlet positioned to communicate with the inside of the housing when the punch is in the retracted state and positioned to be removed from the housing when the punch is in the extended state. Yes,
The hydroforming assembly according to claim 5. The second pressurized fluid is a gas;
Hydroforming assembly as claimed in claim 6. The punch is maintained in the extended state while the flushing fluid is flowing;
Hydroforming assembly as claimed in claim 1. The punch, while the flushing fluid is flowing, reciprocating, hydroforming assembly as claimed in claim 1. The tube end engagement structure retracts from engagement with the end of the tubular blank such that the flushing system is in communication with the inside of the tubular blank;
The hydroforming assembly according to claim 1.   The flushing system includes a waste separator that receives the flushing fluid flow from the die cavity, a fluid reservoir that constitutes a fluid source for the flushing fluid flow, and a circulator that operates the flushing flow. An assembly for hydroforming as described in 1. A method of forming holes in a hydroformed metal tubular blank and removing punched debris from the metal tubular blank,
A plurality of die structures attached to a press for reciprocal movement between an open state and a closed state, comprising a cooperating die surface that forms a die cavity when in the closed state; and Preparing a die structure to be in a state;
Placing a metal tubular blank in the die cavity;
Closing the die structure;
Pressurizing the inside of the tubular blank so as to expand the tubular blank into the die cavity to form an expanded tubular blank; and
Passing a punch through the expanded tubular blank so as to punch holes in the expanded tubular blank ;
Depressurizing the inside of the expanded tubular blank;
Flowing a flushing fluid through the expanded tubular blank so as to flow a punched portion of the expanded tubular blank from the inside of the expanded tubular blank;
With
Wherein the. The punch comprises a fluid passage communicating with the working surface of the punch;
Supplying the pressurized fluid through the fluid passage to push the punched portion of the expanded tubular blank out of the working surface of the punch;
The method of claim 12. A step of reciprocating the punch during the step of flowing the fluid;
The method of claim 12. The depressurization step includes a step of communicating the flushing system inside the expanded tubular blank.
The method of claim 12. The punch is maintained in an extended position extending inside the expanded tubular blank during the flow of fluid;
The method of claim 12.

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