JP4647753B2 - Metal bellows manufacturing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for producing a metal bellows incorporated in an accumulator, a vacuum valve, a pump, or the like.
[0002]
[Prior art]
In the metal bellows, peaks and valleys are alternately formed in the axial direction. In addition to the U shape, various shapes such as a V shape, an Ω shape, and an S shape are known as the cross-sectional shapes (cross-sectional shapes of the pleat walls) of the peaks and valleys. For example, the bellows 1 shown in FIG. 17 has a plurality of crests 2 and troughs 3 that are alternately formed in the axis X direction. Each of the pleat walls 4 and 5 constituting the peak portion 2 and the valley portion 3 has an S-shaped cross section.
[0003]
Such an S-shaped cross-sectional bellows 1 has a sufficiently short contact length when compressed in the axial direction as compared with a normal bellows having a U-shaped cross-sectional pleated wall, so that the expansion / contraction stroke from the free length can be increased. There are advantages such as. In addition, the S-shaped cross section referred to in this specification means a shape in which unevenness (curved surface) continuously smoothly in the radial direction of the bellows 1 is alternately formed like a wave, and S in a strict sense. It does not mean a glyph.
[0004]
As a method of manufacturing the metal bellows 1 having an S-shaped cross section, for example, a method is known in which a plurality of disk-shaped bellows elements having an S-shaped cross section formed by pressing are sequentially joined together by welding. Alternatively, a method is also known in which a crest and a trough are integrally formed from a metal base tube, which is a bellows material, by bulging. The former is a so-called welded bellows, and the latter is called an integrally formed bellows. The integrally formed bellows has advantages such as fewer processing steps, higher material yield, and stable quality compared to welded bellows.
[0005]
[Problems to be solved by the invention]
In order to integrally form the bellows having the S-shaped cross section, hydraulic forming may be applied as an example of bulge processing. A bellows manufacturing apparatus that performs hydroforming has a first mold and a second mold that are provided on the outer peripheral side of a base tube that is a material of bellows. Then, by applying a hydraulic pressure from the inside of the raw tube, a part of the raw tube is inflated between the first die and the second die, and these die are moved in a direction approaching each other. The pleat wall is formed by sandwiching a part of the raw tube between the molds.
[0006]
In such a bellows manufacturing apparatus, when the taper angles α1 and α2 of the molding surfaces 36 and 37 of the molds 13 and 14 are small as shown in FIG. When opening in the radial direction, a problem arises in that the bellows is damaged by a part of the molding surfaces 36 and 37 strongly contacting the pleat wall immediately after molding. To avoid scratching the bellows, the taper angles β1 and β2 of the molding surfaces 36 ′ and 37 ′ may be increased as in the molds 13 ′ and 14 ′ shown in FIG. However, the molds 13 'and 14' having a large taper angle β1 and β2 have a large corrugated wall because the distance between the tips C and C of the molds 13 'and 14' is large when the pleat wall is formed. There is a problem that it cannot be molded.
[0007]
Accordingly, an object of the present invention is to provide a bellows manufacturing apparatus capable of forming a pleated wall into an accurate shape without damaging the bellows having an S-shaped cross section.
[0008]
[Means for Solving the Problems]
A bellows manufacturing apparatus according to the present invention for solving the above-mentioned problems is provided with a fixed mold provided on the outer periphery of a raw pipe, and spaced apart from the fixed mold in the axial direction of the raw pipe. A movable mold that is movable in the direction and can be divided in the radial direction of the blank, a first sealing means provided at a position corresponding to the fixed mold on the inner surface of the blank, Second sealing means provided on the inner surface at a position corresponding to the moving mold and forming a hydraulic pressure chamber with the first sealing means, and a pressurized liquid is supplied to the hydraulic pressure chamber said element by moving a portion of the base pipe is located in the hydraulic chamber and the hydraulic pressure supply means for expanding outwardly, the movable die Konzuke Ku in a first direction to said fixed mold by The expanded portion of the tube is plastically deformed between the stationary mold and the moving mold. And type drive mechanism for forming the pleat walls Te, said first direction said movable mold before opening the movable die after the pleat walls are formed in a radial direction of the mother tube in a direction away from the fold wall A small amount retreating means for slightly retreating by a distance equal to or less than half of the pitch of the pleat wall in the second direction opposite to the above, and after the moving mold is retreated by the small amount retreating means, A mold opening / closing mechanism that opens in a direction; and after the moving mold opens in a radial direction, the element pipe is arranged in the same direction as the second direction in the axial direction of the element pipe with respect to the moving mold and the fixed mold. An element feed mechanism for relatively moving a predetermined amount, and having a molding surface for molding a pleated wall having an S-shaped cross section on each of the opposing surfaces of the fixed mold and the movable mold, and the fixed mold Each molding surface of the mold and the moving mold is perpendicular to the axis of the raw tube. The eggplant taper angle of the minute is 10 degrees or less of a narrow angle.
[0009]
The bellows manufacturing apparatus of the present invention supplies pressurized liquid to the hydraulic chamber between the first sealing means and the second sealing means, expands a part of the raw tube to the outside, Move the mold toward the fixed mold. By doing so, a part of the raw tube is sandwiched between the fixed mold and the movable mold and plastically deformed, and a pleated wall is formed. After the pleat wall is formed, the moving mold is slightly retracted in a direction away from the pleat wall by a small amount of retracting means. After that, the moving mold opens in the radial direction. After the moving mold opens in the radial direction, the element pipe moves by a predetermined amount in the axial direction relative to the moving mold and the fixed mold by the element feeding mechanism.
[0010]
In the present invention, the fixed mold and the movable mold include a molding surface for molding a pleated wall having, for example, an S-shaped cross section on the opposing surfaces. In this case, it is preferable that each forming surface has a narrow angle of 10 degrees or less formed by a line segment perpendicular to the axis of the raw tube.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described below with reference to FIGS.
The bellows manufacturing apparatus 10 schematically shown in FIG. 2 bulges a straight tubular thin-walled metal tube 11 which is a metal bellows material by hydraulic pressure. The manufacturing apparatus 10 includes a base frame 12, a mold set 15 including a fixed-side first mold 13 and a moving-side second mold 14, and a second mold 14 connected to the axis of the base tube 11. A mold drive mechanism 16 that moves in the direction, a chuck 17 that holds the blank 11, a mandrel 18 that is inserted into the blank 11, a mandrel drive mechanism 19 that moves the mandrel 18 in the axial direction of the blank 11, And a tube feed mechanism 20 for moving the chuck 17 holding the tube 11 in the axial direction of the tube 11.
[0012]
As shown in FIG. 1, the first mold 13 is held by a first mold holder 30. The second mold 14 is held by the second mold holder 31. The second mold 14 and the mold holder 31 can reciprocate relative to the first mold 13 and the mold holder 30 in the axial direction of the raw tube 11. In the case of this embodiment, the second mold holder 31 is moved in the axial direction of the raw tube 11 integrally with the second mold 14 by the mold drive mechanism 16 (shown in FIG. 2) using an actuator such as a servo motor. It is supposed to be made.
[0013]
The mold drive mechanism 16 includes, for example, a servo motor 16a and a ball screw 16b that is rotationally driven by the servo motor 16a. The mold drive mechanism 16 is rotated by the servo motor 16a in accordance with a pulse input to the servo motor 16a. The mold 14 moves in the axial direction of the raw tube 11. The mold drive mechanism 16 also functions as a small amount of retracting means in the present invention.
[0014]
The molds 13 and 14 and the mold holders 30 and 31 are divided into two in the radial direction (the direction indicated by the arrow W in FIG. 3) by the mold opening / closing mechanism 39 with the dividing surface 38 as a boundary, as shown in part in FIG. It can be done. In the case of this embodiment, the first mold 13 corresponds to the fixed mold referred to in the present invention, and the second mold 14 corresponds to the moving mold. However, conversely, the second mold 14 and the mold holder 31 may be fixed, and the first mold 13 and the mold holder 30 may be moved in the axial direction of the base tube 11.
[0015]
As shown in FIG. 1 and the like, holes 34 and 35 for inserting the raw tube 11 are formed in the molds 13 and 14. According to the pleat walls 4 and 5 of the bellows 1 to be molded (shown in FIG. 17), the molding surfaces 36 and S of the S-shaped cross section are respectively formed on the mutually opposing surfaces of the first mold 13 and the second mold 14. 37 is formed.
[0016]
As shown in FIG. 11, the taper angles α1, α2 of the molding surfaces 36, 37 of the molds 13, 14 are narrow angles of 10 degrees or less. For example, α1 is 6.5 degrees and α2 is 8.9 degrees. FIG. 12 shows molds 13 ′ and 14 ′ (comparative examples) in which the taper angles β1 and β2 of the molding surfaces 36 ′ and 37 ′ exceed 20 degrees. For example, β1 is 20.6 degrees and β2 is 20.4 degrees. The taper angles α1, α2, β1, and β2 referred to here are the base B and the tip C of each molding surface with respect to a line segment A in a direction perpendicular to the axis of each mold (the axis X of the raw tube 11). Is an angle formed by a line segment D connecting the two.
[0017]
The mandrel 18 is provided at the tip of the center rod 41, a cylindrical body 40 inserted into the raw tube 11, a center rod 41 that passes through the inside of the body 40 and is movable in the axial direction with respect to the body 40. The piston-like seal head 42 is provided. A first seal member 45 located on the inner peripheral side of the first mold 13 is provided on the outer peripheral portion of the seal head 42.
[0018]
A second seal member 46 located on the inner peripheral side of the second mold 14 is provided on the outer peripheral portion of the body 40. A hydraulic chamber 47 is formed between the seal members 45 and 46 on the inner surface side of the raw tube 11. The first sealing member 45 functions as the first sealing means referred to in the present invention. The second seal member 46 functions as second seal means in the present invention.
[0019]
The center rod 41 is formed with a fluid pressure introduction port 48 that opens to the fluid pressure chamber 47 and a fluid circulation portion 49 that communicates with the fluid pressure introduction port 48. A fluid pressure supply device 50 (shown in FIG. 2) for supplying a pressurized fluid (for example, water) to the fluid pressure chamber 47 is connected to the fluid circulation portion 49.
[0020]
Below, the bellows manufacturing process performed using the said manufacturing apparatus 10 is demonstrated.
As shown in FIG. 1, the first mold 13 and the second mold 14 are separated from each other, and the molds 13 and 14 are divided into two parts (in a state where they are opened in the radial direction). The raw tube 11 is set to 13 and 14, and the mandrel 18 is inserted into the raw tube 11 from the open end of the raw tube 11.
[0021]
Thereafter, the molds 13 and 14 are closed in the radial direction as shown in FIG. An arrow M1 in FIG. 4 indicates a direction in which the molds 13 and 14 are closed. At this time, the first seal member 45 is positioned on the inner peripheral side of the first mold 13, and the second seal member 46 is positioned on the inner peripheral side of the second mold 14.
[0022]
After that, as shown in FIG. 5, the fluid (for example, water) pressurized by the fluid pressure supply device 50 is supplied to the fluid pressure chamber 47 through the fluid circulation portion 49 and the fluid pressure inlet 48. Due to the pressure of the liquid supplied to the hydraulic pressure chamber 47, a part 11 a of the elementary tube 11 slightly swells in the outer diameter direction between the seal members 45 and 46.
[0023]
As shown in FIG. 6, the second mold 14, the second mold holder 31, the body 40, and the seal member 46 are synchronized with each other while maintaining the hydraulic pressure in the hydraulic chamber 47. It is moved toward the mold 13 in the direction of arrow F1. By doing so, a part 11a of the raw tube 11 is sandwiched between the molding surfaces 36 and 37 of the molds 13 and 14 and plastically deforms, and the pleated walls 4 and 5 having an S-shaped cross section corresponding to the molding surfaces 36 and 37 are formed. Molded.
[0024]
After forming the pleat walls 4 and 5 for one mountain in this way, the second mold 14 is returned by a slight distance Δd by the mold drive mechanism 16 (shown in FIG. 2) in the minute retraction process shown in FIG. It is. That is, the second mold 14 moves backward by a slight distance Δd in the direction away from the first mold 13 (the direction indicated by the arrow R). This distance Δd is set according to the pitch P (shown in FIG. 16) of the pleat walls 4 and 5, for example, Δd is about 2 mm when the pitch P is 4.4 mm, and Δd when the pitch P is 2.8 mm. Is about 1 mm. If the retreating distance Δd becomes too large, the second mold 14 may damage the pleat wall 4 that was previously formed. For this reason, the distance Δd to be moved back is preferably a small amount equal to or less than half of the pitch P.
[0025]
After the second mold 14 is slightly retracted through this minute retraction process, the first mold 13 and the second mold 14 are opened in the radial direction (the direction indicated by the arrow M2) as shown in FIG. Thus, before the molds 13 and 14 are opened, the second mold 14 is slightly retracted in advance by the micro-retraction step, so that the molding surfaces 36 and 37 of the molds 13 and 14 are the pleated walls 4 after molding. , 5 can be avoided and the pleat walls 4, 5 can be prevented from being damaged.
[0026]
After the molds 13 and 14 are opened in the radial direction, the base tube 11 is moved relative to the molds 13 and 14 by a predetermined amount relative to the molds 13 and 14 in the direction indicated by the arrow F2 in FIG. Sent. In addition, the second mold 14 and the mold holder 31 are retracted in the direction indicated by the arrow F3 and returned to the position before molding, and the body 40 and the seal member 46 are also retracted in synchronization therewith.
[0027]
When the molding surface 37 of the second mold 14 is positioned on the front side of the pleat wall 4, the first mold 13 and the mold holder 30 and the second mold 14 and the mold holder 31 are as shown in FIG. Close in the direction of arrow M1. Then, the series of steps shown in FIGS. 5 to 10 are repeated again, so that the next pleat walls 4 and 5 are formed. By forming the pleat walls 4 and 5 one by one in this manner, the primary molded bellows 1 'shown in FIG. 16 is manufactured.
[0028]
In the molds 13 and 14 of this embodiment, the taper angles α1 and α2 of the molding surfaces 36 and 37 are narrow angles of 10 degrees or less as shown in FIG. The distance L between the tips C and C of the molds 13 and 14 with respect to the raw tube 11 becomes small. For this reason, the familiarity of the element tube 11 is improved, the corrugations of the pleat walls 4 and 5 can be sufficiently formed, and the primary molded bellows 1 ′ close to the bellows 1 of the final product shown in FIG. 17 can be manufactured.
[0029]
In addition, by compressing the primary molded bellows 1 'in the axial direction and bringing the pleat walls 4 and 5 into close contact with each other, the radii of curvature of the tip 2a of the crest 2 and the tip 3a of the trough 3 are set as shown in FIG. It can be further reduced.
[0030]
The molding surfaces 36 and 37 of the molds 13 and 14 according to the embodiment have narrow angles of taper angles α1 and α2 of 10 degrees or less, respectively. On the other hand, FIG. 12 shows molds 13 'and 14' in which the taper angles β1 and β2 of the molding surfaces 36 'and 37' exceed 20 degrees. An S-shaped cross-section bellows formed using the molds 13 'and 14' (comparative example) and an S-shaped cross-section bellows formed using the molds 13 and 14 shown in FIG. The durability test results are shown in FIG.
[0031]
As can be seen from FIG. 13, the bellows formed by the molding surfaces 36 and 37 having small taper angles α1 and α2 shown in FIG. 11 are formed by molding surfaces 36 ′ and 37 ′ having large taper angles β1 and β2 shown in FIG. Compared with the bellows molded by the above, the durability is greatly improved. The reason is that when the pleat walls 4 and 5 are formed using the molding surfaces 36 and 37 having small taper angles α1 and α2, compared with the case where the molding surfaces 36 ′ and 37 ′ having large taper angles β1 and β2 are used. Then, it is considered that the S shape of the pleat walls 4 and 5 is stabilized by reducing the distance L between the tip portions C and C of the molds 13 and 14 with respect to the raw tube 11.
[0032]
When the pleat walls 4 and 5 are formed by the molding surfaces 36 and 37 having small taper angles α1 and α2 as shown in FIG. 11, the molds 13 and 14 are opened in the radial direction as they are after the pleat walls 4 and 5 are formed. As a result, part of the molding surfaces 36 and 37 strongly hit the pleat walls 4 and 5 immediately after molding, and the pleat walls 4 and 5 are damaged.
[0033]
Therefore, in the bellows manufacturing apparatus 10 of this embodiment, the mold drive mechanism 16 performs the second metal mold in the above-described minute retraction process immediately after the mold walls 13, 5 are formed and immediately before the molds 13, 14 are opened in the radial direction. The mold 14 is slightly retracted (see FIG. 7). For this reason, when the molds 13 and 14 are opened in the radial direction, it is possible to prevent a part of the molding surfaces 36 and 37 from pressing the pleat walls 4 and 5 immediately after molding, and the pleat walls 4 and 5 are damaged. I was able to prevent sticking.
[0034]
14 and 15 show a bellows manufacturing apparatus 10 'according to the second embodiment of the present invention. This bellows manufacturing apparatus 10 'simplifies the structure of the mandrel 18' by constructing the mandrel 18 'only by the member 40' integrally formed with the seal head 42 'and the body 40'. Other configurations and operations are the same as those in the first embodiment. In the case of the bellows manufacturing apparatus 10 ′ of the second embodiment, when the second mold 14 is moved toward the first mold 13, the seal head 42 ′ and the seal member 45 are connected to the second mold. 14, and the seal member 45 moves in the axial direction while sliding on the inner surface of the raw tube 11 during the movement. Such a configuration simplifies the configuration of the mandrel 18 '.
[0035]
In the above embodiment, the mold drive mechanism 16 itself has a function as a small amount of retracting means. However, in carrying out the present invention, the micro-retracting means may slightly retract the moving mold by a hydraulic or mechanical drive mechanism provided separately from the mold drive mechanism 16.
[0036]
Further, the present invention is suitable for manufacturing a bellows having an S-shaped cross section, but depending on the shape of the molding surface of the mold, such as a V-shaped cross section or a U-shaped cross section, the cross-sectional shape other than the S-shaped may be used. It can also be used for the production of bellows with pleat walls.
[0037]
【The invention's effect】
According to the first aspect of the invention, a bellows having a desired pleated wall such as an S-shaped cross section, a V-shaped cross section, an Ω-shaped cross section, or a U-shaped cross section can be manufactured according to the shape of the molding surface of the mold. . In particular, when the pleat wall is formed by an uneven molding surface such as an S-shaped cross section, even if the taper angle of the molding surface is small, the fold wall of the bellows is damaged by the molding surface when the mold is opened in the radial direction. Can be prevented.
[0038]
According to the present invention, a bellows having a pleated wall having an S-shaped cross section can be manufactured without being damaged. Further , according to the present invention, by forming the pleated wall having an S-shaped cross section with a mold having a molding surface with a small taper angle, the distance between the fixed mold and the tip of the moving mold can be reduced. In addition, by stabilizing the shape of the pleat wall, a highly durable metal bellows can be manufactured, and the fold wall of the bellows can be prevented from being damaged by the molding surface when the mold is opened.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view of a bellows manufacturing apparatus showing a first embodiment of the present invention.
FIG. 2 is a side view schematically showing the whole bellows manufacturing apparatus shown in FIG. 1;
3 is a front view showing a part of a mold opening / closing mechanism of the bellows manufacturing apparatus shown in FIG. 1. FIG.
4 is a cross-sectional view of the bellows manufacturing apparatus shown in FIG. 1 in a state where an element pipe is set in a mold.
5 is a cross-sectional view of the bellows manufacturing apparatus shown in FIG. 1 in a state where hydraulic pressure is applied to the raw pipe.
6 is a cross-sectional view showing a state in which a pleat wall is formed in the bellows manufacturing apparatus shown in FIG. 1;
7 is a cross-sectional view showing a state in which the mold is slightly retracted in the bellows manufacturing apparatus shown in FIG. 1. FIG.
8 is a cross-sectional view showing a state in which a mold is opened in the bellows manufacturing apparatus shown in FIG.
9 is a cross-sectional view showing a state in which one mold is moved in the axial direction in the bellows manufacturing apparatus shown in FIG. 1;
10 is a cross-sectional view of the bellows manufacturing apparatus shown in FIG. 1 with the mold closed.
11 is an enlarged cross-sectional view showing a part of a mold of the bellows manufacturing apparatus shown in FIG.
FIG. 12 is an enlarged cross-sectional view showing a part of a comparative mold having a large taper angle.
FIG. 13 is a diagram showing the endurance test results of bellows manufactured using two types of dies having different taper angles.
FIG. 14 is a partial cross-sectional view of a bellows manufacturing apparatus showing a second embodiment of the present invention.
15 is a cross-sectional view showing a state in which a pleat wall is formed in the bellows manufacturing apparatus shown in FIG.
FIG. 16 is a cross-sectional view of a part of a primary molded bellows.
FIG. 17 is a cross-sectional view of a part of the completed bellows.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Bellows 4, 5 ... Fold wall 10 ... Bellows manufacturing apparatus 11 ... Elementary tube 13 ... 1st metal mold | die (fixed metal mold | die)
14 ... Second mold (moving mold)
16 ... Mold drive mechanism
DESCRIPTION OF SYMBOLS 20 ... Raw-tube feeding mechanism 36, 37 ... Molding surface 39 ... Mold opening / closing mechanism 45 ... 1st sealing member 46 ... 2nd sealing member 47 ... Hydraulic pressure chamber 50 ... Hydraulic pressure supply apparatus

Claims (1)

A fixed mold provided on the outer periphery of the metal base tube as a bellows material;
A movable mold that is arranged apart from the fixed mold in the axial direction of the element pipe, is movable in the axial direction of the element pipe, and can be divided in the radial direction of the element pipe;
First sealing means provided at a position corresponding to the fixed mold on the inner surface of the raw tube;
Second sealing means provided at a position corresponding to the moving mold on the inner surface of the raw tube and forming a hydraulic chamber between the first sealing means;
Hydraulic pressure supply means for expanding a part of the raw pipe located in the hydraulic pressure chamber to the outside by supplying pressurized liquid to the hydraulic pressure chamber;
Wherein the movable die by plastically deformed between the movable die and the expanded the fixed mold a portion of the mother tube by moving Konzuke to Ku first direction (F1) to the stationary mold A mold drive mechanism for forming a pleat wall;
A second direction opposite to the first direction (F1) in the direction of separating the movable mold from the pleat wall before the movable mold is opened in the radial direction of the raw tube after the pleat wall is formed. (R) a minute amount retreating means for slightly retreating by a distance less than half of the pitch of the pleat wall;
A mold opening / closing mechanism that opens the moving mold in a radial direction after the moving mold is retracted by the micro-retracting means;
After the moving mold is opened in the radial direction, the raw pipe is placed in a predetermined amount in the same direction (F2) as the second direction (R) in the axial direction of the raw pipe with respect to the moving mold and the fixed mold. Comprising a raw pipe feeding mechanism for relative movement ,
A molding surface for molding a pleated wall having an S-shaped cross section is provided on the mutually opposing surfaces of the stationary mold and the movable mold, and
The metal bellows manufacturing apparatus , wherein each of the molding surfaces of the fixed mold and the moving mold has a narrow angle of 10 degrees or less formed by a line segment perpendicular to the axis of the base tube. .

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