KR20050071669A - Deformed element pipe for hydraulic bulging, hydraulic bulging device using the element pipe, hydraulic bulging method using the element pipe, and hydraulic-bulged product - Google Patents

Abstract

A deformed element pipe for hydraulic bulging having a peripheral length with an outer diameter gradually increasing or decreasing from one to the other axial side thereof and having a parallel part formed at least one end thereof, and a hydraulic bulging device and a hydraulic bulging method using the element pipe, the device and the method whereby, for example, even when a deformed steel pipe having a cross sectional shape varying in the axial direction as in a tapered pipe is hydraulically bulged, a bulging in which an internal pressure loading and an axial pressing are combined with each other can be performed to provide a larger expansion ratio than before and the joining and plug-in connection thereof to the other part can also be easily performed.

Description

Deformed element pipe for hydraulic bulge processing, hydraulic bulge processing apparatus, hydraulic bulge processing method and hydraulic bulge processed product using the same }

TECHNICAL FIELD The present invention relates to a mold release pipe provided for a hydraulic bulge processing, and a hydraulic bulge processing device for performing hydraulic bulge processing using the mold release pipe, a hydraulic bulge processing method, and a hydraulic bulge processed product subjected to hydraulic bulge processing. will be.

Hydraulic bulging has many features compared to other molding processes. For example, since it can process into the complicated shape component from which the cross-sectional shape differs in the longitudinal direction, the mechanical component which required the welding joint can be processed by integral molding in the conventional method. In addition, in order to produce work hardening over the whole part to which work is given, even if a soft element pipe is used, a high-strength product can be obtained.

Moreover, there is little springback after processing, and the dimensional precision of a product is favorable (shape freezing property is favorable). For this reason, the correction | amendment process of a product dimension is not needed and a process can be abbreviate | omitted.

Hydraulic bulging has been evaluated for its excellent features, and in recent years, has been adopted as a method for producing automotive parts in particular.

In general, in the case of forming a tube by hydraulic bulging, a straight tube (hereinafter referred to as a "straight tube") having a uniform distal surface in the longitudinal direction is used as a material, and the material is " preformed " After bending and crushing, the hydraulic bulging is carried out as the final step of the machining step. By passing through such a series of processing processes, the hydraulic bulge processed product processed into the predetermined shape from a straight element pipe can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the final process of the hydraulic bulging process of obtaining a product using the conventional straight pipe. As shown in Fig. 1, in the hydraulic bulge processing as the final process, the processing liquid is injected through the injection hole 3 into the straight pipe P1 set in the upper and lower molds 1 and 2 to load the internal pressure. In addition, the element pipe P1 is press-fitted from both pipe ends in the axial direction by the axial pressing tools 4 and 5 which serve as a sealing tool in addition to the pressure resistance load (hereinafter referred to as "axial pressing").

In hydraulic bulge processing, the product P2 which has various cross-sectional shape is manufactured by combining internal load and axial compression. Moreover, the axial press tools 4 and 5 which served as the sealing tool are connected to the hydraulic cylinder which is not shown in figure, and the axial direction position and the axial press force are controlled during hydraulic bulging processing.

Axial pressing from the tube end to the axial direction in the hydraulic bulging process promotes the metal flow during expansion of the element pipe, thereby improving the effect of expanding the element pipe. For this reason, the axial press from the tube end to the axial direction is a very important machining step in the hydraulic bulging process.

Specifically, in the hydraulic bulging process, when the machining is performed only with the internal pressure load without applying the axial pressure, the plate thickness of the straight tube P1 is significantly reduced due to expansion. For this reason, the straight element pipe P1 leads to breakage during the hydraulic bulging process. That is, the moldable range (expansion effect) of the straight element pipe P1 is limited.

In addition, there is a problem due to the element pipe shape in the hydraulic bulge processing. As described above, as one of the features of the above processing, even if a complicated processing shape having a different cross-sectional shape in the axial direction can be obtained, there is a limitation in the processing shape that can be obtained.

For example, when defined as the peripheral length increase rate (expansion rate) = {(the circumferential length of the workpiece of the corresponding site / the circumferential length of the pipe) -1} x 100%, the shape characteristics required for the workpiece and the pipe condition used Material, sheet thickness), but the circumferential length increase rate (expansion rate) is only about 25%, with the exception of the tube end region in which axial compression is effective.

Hydraulic bulge processing cannot be performed beyond the perimeter increase rate (expansion rate) of this limit. In order to raise the degree of freedom of shape design of a workpiece | work on the basis of such a constraint of an increase in peripheral length (expansion rate), and to obtain the workpiece | work which has a more complicated cross-sectional shape, it is necessary to devise in a small pipe shape.

In order to cope with this problem, it is proposed to use a substantially conical elementary pipe (hereinafter referred to as "taper elemental pipe") instead of the straight elemental pipe. That is, by using a taper element pipe, even if the part which is difficult to shape | mold in a straight element pipe | tube, for example, the part whose peripheral length changes largely along the axial direction, the peripheral length increase rate can be suppressed low with a process, and a predetermined process shape is formed. (See, for example, Japanese Patent Laid-Open No. 2001-321842, first page, and FIG. 2).

However, when performing hydraulic bulge processing using a taper element pipe whose cross-sectional shape changes in the axial direction, it is difficult to axially press the taper element pipe when the axial pressing tool for straight tube pipe shown in Fig. 1 is used.

Fig. 2 is a view for explaining a problem which occurs when the shaft presses on the tapered element pipe with a conventional straight tube pipe pressing tool. As shown in Fig. 2, the shaft pressing itself to the tapered element pipe TP1 cannot be performed on the large diameter side, and the shaft pressing on the taper element pipe TP1 can be performed on the small diameter side. As 4) enters the inside of the upper and lower molds 1 and 2, the restraint of the inner and outer surfaces of the tapered element pipe TP1 on the side of the axial pressing tool 4 becomes insufficient, and the sealing leakage occurs.

Figure 3 is a view for explaining a conventional hydraulic bulge processing process using a tapered element pipe, Figure 3 (a) is a state before processing, (b) is a state before applying a pressure-resistant load, (c) is at the end of processing Indicates the state of.

In the conventional hydraulic bulge processing using the tapered element pipe TP1, as shown in FIG. 3, although the axial pressing tools 6 and 7 which have a tapered shape at the tip end cannot be axially pressed, axial pressure cannot be applied. It is common to complete bulge processing. In addition, in FIG. 3, TP2 shows the taper element pipe after shape | molding a pipe end part, and TP3 shows the product (hydraulic bulge processed product) after hydraulic bulging processing.

In the machining step shown in Fig. 3, the axial compression of the tapered element pipe TP2 cannot be performed. Therefore, machining cannot be performed only in a limited molding range such that no breakage occurs in the step of hydraulic bulging as described above. Therefore, it is a fact that the effect of using a taper element pipe in a hydraulic bulging process is not fully exhibited.

For this reason, when a hydraulic bulge process is performed using a taper element pipe, the development of the technology which enables the axial press from the tube end to the axial pressure load to a element pipe is anticipated.

In addition to the problem that axial compression is difficult when the conventional tapered element pipe is subjected to hydraulic bulging, there is also a problem when the hydraulic bulge processed product is joined to another member.

It is a figure explaining the problem at the time of joining the hydraulic bulge processed goods which have a rectangular cross section. Figure 4 (a) shows the shape of a conventional hydraulic bulge workpiece, (b) shows the shape of the hydraulic bulge workpiece of the present invention, and shows the inclination of the pipe end with respect to the axial direction of each workpiece. . (c) has shown the cross-sectional shape of the hydraulic bulge processed goods of said (a) and (b).

As shown in Fig. 4A, the pipe end is inclined and inclined by θ, as shown in Fig. 4A. For this reason, since precision cannot be ensured at the time of welding and joining with another member, joining with another member is not easy.

In addition, since the precision cannot be secured at the same time as the inserting engagement in which the pipe end is inserted into another part and engaged, positioning becomes difficult. Therefore, the finishing process, such as cutting out the edge part of a hydraulic bulge processed product after hydraulic bulge processing, is required.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the final process of the hydraulic bulging process of obtaining a product using the conventional straight pipe.

Fig. 2 is a view for explaining a problem caused when a shaft pressing of a conventional tapered tube is performed using a conventional straight tube pressing tool.

3 is a view illustrating a conventional hydraulic bulge processing process using a tapered element pipe, where (a) is a state before processing, (b) is a state before applying a pressure-resistant load, and (c) is a state at the end of processing. It is shown.

4 is a view for explaining a problem in the case of joining a hydraulic bulge workpiece having a rectangular cross section, (a) is the shape of the hydraulic bulge workpiece using a conventional tapered pipe, (b) is the shape of the hydraulic bulge workpiece of the present invention (C) shows these cross-sectional shapes.

It is sectional drawing which shows the shape example of the taper pipe which comprises the mold release tube for hydraulic bulge processing of this invention.

6 is a view illustrating the overall configuration of the release tube of the present invention, (a) is an example in which parallel portions having a distal surface are formed at both ends of the tapered portion having the distal surface, and (b) is a tapered portion having a rectangular cross section. The example which provided the parallel part which has a rectangular cross section in both ends is shown.

Fig. 7 is a diagram illustrating the overall configuration of another mold release tube of the present invention, showing an example having transition portions between the parallel portion on the large diameter side and the tapered portion on the center.

Fig. 8 is a view for explaining a method for producing a release element tube according to the present invention having a parallel portion at a large diameter side end, where (a) is an overall perspective view, (b) is a developed view, and (c) is in (b). It is a figure which shows the trapezoid shape near the developed figure shown.

9 is a view showing another embodiment of the release tube of the present invention and the axial pressing tool used in them, (a) is an overall perspective view, (b) is an enlarged view of the small diameter side, (c) It is an enlarged view of the axial press tool which served as the sealing tool of the small diameter side used for the.

Fig. 10 is a view showing the end face shape of the mold release tube of the present invention used when the small diameter side of a hydraulic bulge workpiece has a rectangular cross section, and (a) is a position δL + L0 in the axial direction from the small diameter side end portion. (C) is sectional drawing of a tube end part, (b) is sectional drawing in those intermediate positions.

Fig. 11 is a view showing the end face shape of the mold release tube of the present invention used when the large diameter side of a hydraulic bulge workpiece has a rectangular cross section, and (a) is δL '+ L0' away from the large diameter side end in the axial direction. Sectional drawing of a position, (c) is sectional drawing of a pipe end part, (b) is sectional drawing in those intermediate positions.

12 is a diagram illustrating the cross-sectional shape when the hydraulic bulge workpiece has a trapezoidal cross section.

Fig. 13 is a diagram illustrating the cross-sectional shape in the case where the hydraulic bulge processed article has an L-shaped cross section.

Fig. 14 is a view for explaining a first embodiment of the method of the present invention, showing the case where the parallel portion of the tube end portion of the mold release tube is formed prior to the hydraulic bulge processing, and (a) shows the tapered pipe to the mold body. It is sectional drawing which shows a setting state, (b) is sectional drawing which shows the state which formed the parallel part before hydraulic bulging processing, (c) is sectional drawing which shows the state after completion of hydraulic bulging processing.

Fig. 15 is a diagram showing the relationship between the upper mold body on the small diameter side, the shaft pressing tool serving as a sealing tool, and the mold release tube end portion, wherein (a) to (c) correspond to Figs. 14 (a) to (c). Drawing.

Fig. 16 is a diagram showing the relationship between the upper mold body on the large diameter side, the shaft pressing tool serving as a sealing tool, and the mold release tube end portion, wherein (a) to (c) correspond to Figs. 14 (a) to (c). Drawing.

FIG. 17 is a view for explaining a second embodiment of the method of the present invention, showing the case where the parallel portion of the tube end portion of the mold release tube is formed in advance before setting to the mold body, and (a) shows the mold of the mold release tube. It is sectional drawing which shows the setting state to a main body, (b) is sectional drawing which shows the state before hydraulic bulging processing, (c) is sectional drawing which shows the state after completion of hydraulic bulging processing.

Fig. 18 is a view for explaining a third embodiment of the method of the present invention, which shows another example in the case where the parallel portion of the tube end portion of the mold release tube is formed before setting to the mold body, (a) to (c). ) Is the same as the case of FIG.

Fig. 19 is an explanatory diagram showing a fourth embodiment of the method of the present invention, showing a configuration example in which the cavity inside the parallel part on the large diameter side monotonously increases in the axial direction with respect to the large diameter end, and (a) to (c). ) Is the same as the case of FIG.

It is a figure which shows the structural example of the axial pressing tool which also served as the sealing tool which is a structural member of the hydraulic bulge processing apparatus of this invention.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and in the hydraulic bulge processing using a deformed element pipe in which the cross-sectional shape is changed in the transverse direction, an axial pressure in the axial direction from the end of the pipe can be added to the pressure load to the element pipe. An object of the present invention is to provide a release duct for hydraulic bulge processing, a hydraulic bulge processing apparatus, a hydraulic bulge processing method, and a hydraulic bulge processed product which can obtain a large expansion rate.

In order to achieve the above object, the release element pipe for hydraulic bulge processing of the present invention is a release element pipe provided for hydraulic bulge processing, and has a peripheral length in which the outer diameter gradually increases or decreases from one side in the axial direction to the other side, and at least one The parallel part is formed in the side end part.

In the release element pipe for hydraulic bulge processing of this invention, it is preferable to make the length of the said parallel part more than the total length of the axial compression amount performed by hydraulic bulge processing, and the length required for sealing at the time of processing.

Moreover, in the release element pipe provided for manufacture of a hydraulic bulging workpiece which has a rectangular cross section or a polygonal cross section, the radius of curvature R of the corner part in the said parallel part is the periphery of the release element pipe corresponding to the axial distance of a pipe end part. It is preferable to change it corresponding to the change of length difference.

And the mold release tube of this invention which consists of such a structure is provided with the parallel part in the inner surface of at least one end side of the upper and lower mold bodies, and the outer surface of the axial press tool corresponding to this end side inner surface, respectively, and the hydraulic pressure of this invention When set in the metal mold | die of a bulge processing apparatus, it becomes possible to combine a pressure-resistant load and an axial press.

As a result, in the hydraulic bulging process, a large expansion ratio can be obtained more than conventionally, and the joining with other parts can be easily performed.

Fig. 5 is a cross-sectional view showing a shape example of a tapered pipe that constitutes the release small pipe of the present invention. The release element pipe 11 for hydraulic bulge processing of the present invention is a release element pipe provided for hydraulic bulge processing, and the outer diameter gradually increases from one side to the other in the axial direction as shown in Figs. 5 (a) and 5 (b). Alternatively, parallel portions 11a and 11b are formed on at least one end portion (both ends of the small diameter side and the large diameter side in the example shown in Fig. 5) with a reduced peripheral length.

In the release element pipe for hydraulic bulge processing of this invention, it is preferable to make the length of the said parallel part 11a, 11b more than the total length of the axial press amount in hydraulic bulging processing, and the length required for sealing.

Figure 6 is a view illustrating the overall configuration of the release element pipe of the present invention, Figure 6 (a) is an example in which the parallel portion having the distal surface is formed at both ends of the tapered portion having the distal surface, (b) is a rectangular cross section The example which provided the parallel part which has a rectangular cross section in the both ends of the taper part to have is shown.

The embodiment shown in Fig. 5A will be described in more detail with reference to Figs. 6A and 6B. Fig. 6A shows the most basic form, in which parallel portions 11a and 11b having the distal surface are formed at both ends of the tapered portion having the distal surface.

6B, parallel portions 11a and 11b having rectangular cross sections are provided at both ends of the tapered portion having a rectangular cross section. In the example shown in FIG. 6 (b), the parallel portions 11a and 11b have a cross section shown in FIG. 10 (a) which will be described later on the small diameter side 11a over the entire length, and will be described later in the large diameter side 11b. FIG. 11C has a cross section shown in FIG.

Fig. 7 is a view illustrating the overall configuration of another release element pipe according to the present invention, and shows a configuration example of the release element pipe having a transition portion between the parallel part on the large diameter side and the taper part in the center as compared with the configuration in Fig. 6.

Next, the details of the embodiment shown in Fig. 5B will be described with reference to Figs. 7A and 7B. Fig. 7 (a) shows parallel portions 11a and 11b having the distal surface at both ends of the tapered portion having the distal surface. The transition portion 11c is provided between the parallel portion 11b on the large diameter side and the central tapered portion. Have

Fig. 7B is provided with parallel portions 11a and 11b having a rectangular cross section at both ends of the tapered portion having a rectangular cross section, and is arranged between the parallel portion 11b on the large diameter side and the central tapered portion. Similarly, it has the transition part 11c.

6 (b) and 7 (b) show that the shapes of the parallel portions 11a and 11b formed at both ends simply have a rectangular cross section, the shapes of the parallel portions 11a and 11b will be described later. It may be a trapezoidal cross-sectional shape as shown in Fig. 12, an L-shaped cross-sectional shape as shown in Fig. 13 to be described later, or a polygonal cross-sectional shape not shown.

In this case, if the final end surface shape after hydraulic bulging processing is designed to match the end surface shape of a product, material yield will improve and it is suitable.

6 (b) and 7 (b) show that the center taper portion is also a rectangular cross section, the center portion is not particularly rectangular in cross section. The raw material surface as shown in (a) may be sufficient, and what was bent and crushed from top, bottom, left, or right may be inserted so that it may be inserted in the metal mold | die of a hydraulic bulging process.

FIG. 8 is a view for explaining a method for producing a release element tube according to the present invention having a parallel portion at a large diameter side end, where FIG. 8A is an overall perspective view, FIG. 8B is an exploded view, and FIG. It is a figure which shows the trapezoid shape close to the developed view shown in ().

The manufacturing method of the mold release tube 11 which concerns on this invention which has a parallel part 11b in the large diameter side end part of the taper part which has a distal surface as shown to Fig.8 (a) is as follows.

The release tube 11 shown in FIG. 8 (a) simply distorts the plate of the shape shown in FIG. 8 (b) and a-b and a'-b ', c-d and c'-d'. When the ends of b-e and c-e, and b'-e and c'-e are joined together, as shown in Fig. 8 (a), the mold release tube 11 having the parallel portion 11b at the large diameter side end portion thereof is shown. ) Can be obtained.

On the other hand, in Fig. 8C, Fig. 8B is shown in broken lines and a trapezoidal shape close to this is shown by a solid line.

As apparent from the comparison between the solid line and the broken line, when the trapezoid shown by the solid line in Fig. 8 (c) is simply distorted, the thickness of the b-c-e and the b'-c'-e 'regions is excessive. Occurs. That is, in the plate winding process which used the trapezoid shape as a raw material, it is difficult to manufacture the mold release tube which has the parallel part 11b at the edge part like the mold release tube 11 which concerns on this invention.

The simplest method is a method of simply distorting and joining a plate having a developed shape of the release tube 11 according to the present invention as described with reference to FIG. 8. Next, a method of manufacturing the mold release tube 11 according to the present invention having the shape shown in FIG. 7 will be described.

In the case of the shape shown in Fig. 6A, for example, a "simple taper pipe" can be used as a raw material, and the small diameter side can be obtained by expanding the inner diameter and the large diameter side by performing the outer diameter throttling. In addition, in the case of the shape shown in FIG.6 (b), it can obtain by performing crushing process to the main-body length part in addition to the above.

In the description of the present invention, the term "simple taper pipe" means a taper pipe which is a raw material of the mold release tube of the present invention and which does not yet have parallel portions at one end side or both ends.

In the case of the shape shown in Fig. 7A, the inner diameter expansion processing may be performed on both the small diameter side and the large diameter side using, for example, a "simple taper pipe". In addition, in the case of the shape shown in FIG.7 (b), it can obtain by performing crushing process to the main body length part in addition to the above.

Fig. 9 is a view showing another embodiment of the release tubule of the present invention and the axial pressing tool used therein, Fig. 9 (a) is an overall perspective view, (b) is an enlarged view of the small diameter side, (c ) Is an enlarged view of the shaft pressing tool which also serves as a sealing tool on the small diameter side used for them. In the embodiment shown in FIG. 9, the form shown to Fig.9 (a) forms the parallel part 11a, 11b of a rectangular cross section in the both ends of the tapered part of a rectangular cross section.

In addition, in the Example shown in FIG. 9, the part corresponding to (delta) L + L0 in the parallel part 11a of the small diameter side to the simple taper pipe, and the part corresponding to (delta) L '+ L0' in the parallel part 11b of the large diameter side The rectangular cross section which has the width | variety and the dimension of height substantially the same as a product is formed.

In addition, by determining the radius of curvature R of the corner portion as will be described later, the axial pressure at the time of hydraulic bulge processing by the axial pressing tools 14 and 15 which also serve as the mold bodies 12 and 13 and the sealing tool in the hydraulic bulging process. As a result, buckling and the like do not occur and a very smooth indentation of the material is applied.

Fig. 10 is a diagram showing the end face shape of the mold release tube of the present invention used when the small diameter side of the hydraulic bulge processed article has a rectangular cross section. Fig. 10 (a) shows a cross section at a position δL + L0 in the axial direction from a small diameter side end portion, (c) shows a cross section at a tube end portion, and (b) shows a cross section at their intermediate positions.

That is, FIG. 10 is a figure explaining the shape in each cross section of the parallel part 11a of the small diameter side of the mold release tube of this invention, The width W0 and height H0 of the cross section of (a)-(c). ) Is almost constant. In addition, the curvature radius R of a corner part is changing stepwise by preforming.

As shown in Figs. 10A to 10C, the radius of curvature of the corner portion at the small-diameter side end is R0, and the radius of curvature of the corner portion at the position δL + L0 in the axial direction from the small-diameter side end is R1, the small-diameter. If the radius of curvature of the corner portion at the position axially separated from the side end portion is R (x), these become relations of the following formula (1).

[Equation 1]

R0 ≥ R (x) ≥ R1

In the embodiment shown in Fig. 10, the radius of curvature of the four corner portions in each cross section is the same, but it is not necessary to make them the same, and the radius of curvature may be different for each corner portion.

More specifically, the peripheral length difference [delta] d (x) at the position X from the pipe end with both end portions of the simple tapered pipe as the reference peripheral length can be obtained by the following equation. D0 is a small diameter side outer diameter, D0 'is a large diameter outer diameter, and LT has shown the length of a taper pipe.

[Equation 2]

delta d (x) = π (D0 '-D0)

In forming a cross section of an end portion in a rectangle of width W0 and height H0 in the preform, the radius of curvature R of the corner portion corresponds to the peripheral length difference δd (x), as shown in FIG. By changing the dimensions of (x)] at the axial position, the shape of the appropriate preform can be determined.

Fig. 11 is a diagram showing the end face shape of the mold release tube of the present invention used when the large diameter side of a hydraulic bulge workpiece has a rectangular cross section. Fig. 11A is a sectional view of a position δL '+ L0' away from the large diameter side end portion, (c) is a sectional view of the tube end portion, and (b) is a sectional view at their intermediate position.

That is, FIG. 11 is a figure explaining the shape in each cross section of the parallel part 11b of the large diameter side of the mold release tube of this invention, Comprising: The width W0 'of the cross sections of (a)-(c), and height ( H0 ') is nearly constant. In addition, the curvature radius R 'of a corner part is changing stepwise by preforming.

As shown in Figs. 11A to 11C, the radius of curvature of the corner portion at the large-diameter end is R0 ', and the radius of curvature of the corner portion at a position δL' + L0 'away from the large-diameter end in the axial direction. If the radius of curvature of the corner portion at the position axially separated from R1 'and the large-diameter side end portion is R' (x), these become relations of the following formula 1 '.

[Equation 1 ']

R0 '≤ R' (x) ≤ R1 '

In addition, the peripheral length difference (delta d (x)) at the position X from the edge part which made both ends of a simple taper pipe the reference peripheral length can be obtained by following formula 2 '. D0 is a small diameter side outer diameter, D0 'is a large diameter outer diameter, and LT has shown the length of a taper pipe.

[Equation 2 ']

δd (x) = π (D0'-D0) X / LT

When the cross section of the end is formed into a rectangle of width W0 'and height H0', the radius of curvature R 'of the corner portion corresponds to the peripheral length difference δd (x), as shown in FIG. By changing the dimension of x) at the axial position, an appropriate shape can be determined.

As described above, the case where the hydraulic bulge processed product has a rectangular cross section has been described. However, the release element pipe of the present invention is not limited to this, and even a rectangular combination shape or a polygonal shape can be adopted, and the hydraulic bulge processing can be very stable. Axial compression is possible.

12 is a diagram illustrating the cross-sectional shape when the hydraulic bulge workpiece has a trapezoidal cross section. Fig. 13 is a diagram illustrating the cross-sectional shape in the case where the hydraulic bulge processed article has an L-shaped cross section. As an example of the cross-sectional shape previously formed on the large diameter side, (a) is a sectional view of the position delta L '+ L0' away from the large diameter side end part, (c) is a sectional view of the tube end part, and (b) It is sectional drawing in the intermediate position of.

Next, the hydraulic bulge processing apparatus of this invention and the hydraulic bulge processing method using the same are demonstrated based on drawing.

FIG. 14 is a view for explaining a first embodiment of the method of the present invention, showing the case where the parallel portion of the tube end portion of the mold release tube is formed before the hydraulic bulge processing. Fig. 14 (a) is a sectional view showing a setting state of the tapered pipe to the mold main body, (b) is a sectional view showing a state in which parallel portions are formed before the hydraulic bulge processing, and (c) is a view after completion of the hydraulic bulge processing. It is sectional drawing which shows the state.

Fig. 15 is a diagram showing the relationship between the upper mold body on the small diameter side, the shaft pressing tool serving as a sealing tool, and the mold release tube end portion, and Figs. 15 (a) to (c) are Figs. 14 (a) to (c). It corresponds to drawing.

Fig. 16 is a view showing the relationship between the upper mold body on the large diameter side, the axial pressing tool serving as a sealing tool, and the mold release tube end portion, and Figs. 16A to 16C show Figs. 14A to 14C. It corresponds to drawing.

Fig. 17 is a view for explaining a second embodiment of the method of the present invention, showing the case where the parallel portion of the tube end portion of the mold release tube is formed before setting to the mold body. Fig. 17 (a) is a sectional view showing a setting state of the mold release tube to the mold main body, (b) is a sectional view showing a state before hydraulic bulging, and (c) shows a state after completion of hydraulic bulging. It is a cross section.

Fig. 18 is a view for explaining a third embodiment of the method of the present invention, and shows another example in the case where the parallel portion of the tube end portion of the mold release tube is formed before setting to the mold body. Fig. 18 (a) is a cross sectional view showing a setting state of the mold release tube to the mold body, (b) is a sectional view showing a state before hydraulic bulging, and (c) shows a state after completion of hydraulic bulging. It is a cross section.

The hydraulic bulge processing apparatus of the present invention is, for example, each of the upper and lower mold bodies 12 and 13 in which the cavity is formed as shown in Figs. 14, 17 and 18, and each of the mold bodies 12 and 13, respectively. The shaft pressing tools 14 and 15 which serve as the sealing tool in which the tip part is inserted in the edge part are provided. And both the mold main bodies 12 and 13 and the shaft pressing tools 14 and 15 are comprised so that both ends of the mold release tube 11 of this invention may be pinched and hold | maintained.

Further, an injection hole for the processing liquid is provided in any one of the shaft pressing tools, and at least one end side of the mold body (in the example shown in Figs. 14, 17, and 18, both the small diameter side and the large diameter side both sides). The parallel portions 12a, 12b, 13a, 13b, 14a, and 15a are provided on the inner surface and the outer surface of the shaft pressing tool corresponding to the inner surface of the end face.

The parallel portions 14a and 15a of the outer surfaces of the shaft pressing tools 14 and 15 have an effect of restraining element pipes from the inner surface at the time of shaft pressing to enable smooth deformation.

In this hydraulic bulge processing apparatus, δL is the amount of axial compression on the small diameter portion, δL 'is the amount of axial compression on the large diameter portion, L0 is the length required for sealing on the small diameter portion, and L0 is the length required for sealing on the large diameter portion. Is a parallel portion 12a provided on the inner surface of at least one end side of both mold bodies 12 and 13 (in the example shown in Figs. 14, 17 and 18, both ends of the small diameter side and the large diameter side). , 12b, 13a, 13b) is preferably δL + L0 or more when provided on the small diameter side, and δL ′ + L0 'or more when provided on the large diameter side.

Similarly, the lengths of the parallel portions 14a and 15a of the shaft pressing tools 14 and 15 corresponding to the parallel portions 12a, 12b, 13a and 13b provided in the mold bodies 12 and 13 are on the small diameter portion side. When provided, it is preferable to set it as (delta) L + L0 or more, and when it is installed in the large diameter part side, it is set to L0 'or more.

By the way, in the hydraulic bulge processing apparatus of this invention, the front-end | tip part of the shaft pressing tool 14 (15) which served as the sealing tool of the small diameter side (large diameter side) is a simple taper pipe PT which becomes a raw material of the release small pipe 11, or It should be insertable into the small diameter side end (large diameter side end) of the mold release tube 11. At the same time, it is necessary for the parallel portions 14a and 15a not to have a gap between the uppermost portion of the parallel portions 14a and 15a at the time of axial compression completion and the inner surface of the mold release tube 11. .

For this reason, for example, as shown in FIG. 14, the parallel part formed in the pipe end part after setting the simple taper pipe PT used as the raw material of the mold release pipe 11 as the upper and lower mold main bodies 12 and 13, respectively. When forming 11a, 11b in the upper and lower mold main bodies 12 and 13 before performing a hydraulic bulge process, the axial press tool which also serves as a sealing tool needs to satisfy the following conditions A and B.

A. Axial compression tool 14 also serves as a sealing tool on the small diameter side (see Fig. 15).

The circumferential length SD0 of the envelope ignoring the local recess of the tip portion satisfies the following expression (3).

[Equation 3]

SD0 ≤ (D0-2t / cosθ) × π

D0: Outer diameter of small diameter part

t: thickness of mold release tube 11

θ = tan ^-1 {(D0 '-D0) / (2LT)}

LT: length of taper pipe (PT)

D0 ': outer diameter of large neck

B. Axial Compression Tool 15, also serving as Large Diameter Sealing Tool (see Fig. 16)

The peripheral length SD0 'of the envelope, ignoring the local recess of the tip, satisfies Expression 4 below.

[Equation 4]

SD0 '≤ (D0'-2t / cosθ) × π

On the other hand, as shown in FIG. 17, when the parallel parts 11a and 11b formed in the tube end part of the mold release tube 11 are previously formed before being set to the upper and lower mold main bodies 12 and 13, it is sealed. The axial pressing tool which also serves as a tool satisfies the conditions of the following C and D.

C. Axial Compression Tool 14 that also serves as a sealing tool on the small diameter side (see Fig. 17).

The peripheral length SD0 of the tip portion satisfies Expression 5 below.

[Equation 5]

SD0 ≤ peripheral length SD of parallel part 14a

D. Axial compression tool 15 which also serves as sealing tool on large diameter side (see Fig. 17)

The peripheral length SD0 'of the tip portion satisfies Expression 6 below.

[Equation 6]

SD0 '? Ambient Length SD' of Parallel Part 15a

In the case of forming the hydraulic bulge processed product 17 using the hydraulic bulge processing apparatus of the present invention, for example, a simple tapered pipe PT which is a raw material of the release small pipe 11 of the present invention is shown in Fig. 14A. As shown in the figure, it is set in a pair of mold bodies 12 and 13 of the hydraulic bulge processing apparatus.

Next, prior to the hydraulic bulge processing, the axial pressing tools 14 and 15 serving as the sealing tools are moved in the axial direction, and the tapered pipe PT sandwiched between the mold bodies 12 and 13 and the axial pressing tools 14 and 15 is carried out. ), Parallel portions 11a and 11b are formed in the tube end portion or both ends thereof to form the mold release tube 11 according to the present invention.

At this time, it is not necessary to make the timing of the axis press of the mold release pipe 11 by the axis press tool 14, 15 the same, for example, the axis press tool at the stage which pressed the axis press tool 15 to some extent. The pressure of (14) may be started. Therefore, what is necessary is just to select the axial press timing by which the mold release tube 11 is stabilized in the metal mold | die main body 12, 13 (12, 13).

In this case, when the dimension design of the shaft press tools 14 and 15 which served as the mold main body 12 and 13 and the sealing tool based on the dimension mentioned above is carried out, the shaft press tools 14 and 15 are tapered pipe (TP). ) Can be inserted smoothly.

In the state shown in Fig. 14B, as shown in Figs. 15B and 16B, both ends of the tapered pipe PT are L0 or more, preferably δL, on the small diameter side. The parallel parts 11a, 11b of + L0 or more and L0 'or more length are formed in the large diameter side, and the mold release tube 11 of this invention is obtained. Thereafter, the release element pipe 11 is loaded with internal pressure in a state where sealing of the processing liquid is completely performed.

Subsequently, the axial pressing tools 14 and 15 are further moved in the axial direction while raising the internal pressure of the processing liquid to perform hydraulic bulging, and the hydraulic pressure according to the method of the present invention as shown in FIG. The bulge workpiece 17 is formed.

That is, in the hydraulic bulge processing in which the mold release tube 11 of the present invention is set in the hydraulic bulge processing apparatus of the present invention, axial compression becomes possible, and as a result, the hydraulic bulge processed product 17 according to the method of the present invention is larger than conventional. The expansion rate can be obtained.

In addition, since the end face of the hydraulic bulge workpiece 17 is perpendicular to the shaft center as shown in Fig. 4 (b), the joint welding with other parts and members can be easily performed. The decision becomes possible.

Fig. 19 is an explanatory diagram showing a fourth embodiment of the method of the present invention, showing a configuration example in which the cavity inside the parallel portion on the large diameter side smoothly increases in the axial direction with respect to the large diameter end portion. Fig. 19 (a) is a cross sectional view showing a setting state of the tapered tube to the mold main body, (b) is a cross sectional view showing a state where parallel portions are formed before the hydraulic bulge processing, and (c) is a view after completion of the hydraulic bulge processing. It is sectional drawing which shows the state.

The embodiment shown in FIG. 19 is a form different from the embodiment shown in FIG. 14, FIG. 17, and FIG. That is, although the parallel part 12a, 12b, 13a, 13b is the same in the both ends of both mold main bodies 12 and 13, it is the inside of parallel part 12b, 13b of the large diameter side of both mold main bodies 12 and 13, respectively. The cavity of is not narrowed locally as in the example shown in Fig. 14 and the like, and the cavity inside the parallel portions 12b and 13b is smoothly reduced in the axial direction with respect to the large-diameter end.

In the structural example shown in Fig. 19, the resistance of the shaft pressing is small and advantageous to the metal flow, so that the moldable range (expansion effect) can be expanded. Therefore, in the hydraulic bulge processing apparatus of this invention, it is preferable to design the cavity shape of the metal mold | die main bodies 12 and 13 to the shape shown in FIG.

On the other hand, in automobile parts, there are many complicated shapes, such as the cross-sectional shape of the edge part of a product being close to a rectangle, a combination of rectangles, or a shape, such as a polygon.

As described above, Fig. 18 is a view showing an embodiment in the case of using the release element pipe 11 of the present invention shown in Fig. 9A. The mold release tube 11 shown is set in the mold main bodies 12 and 13. Fig. 9B shows an enlarged view of the small diameter side of the mold release tube 11 of the present invention. In addition, the cross-sectional shape of the small diameter side parallel part 11a is as showing in FIG.

The mold release tube 11 having such a cross-sectional shape is molded by using the shaft pressing tools 14 and 15 that also serve as sealing tools according to one example of the present invention. That is, Fig. 9 (c) shows the shaft pressing tool 14 serving as the sealing tool on the small diameter side, but the parallel portion 14a having the width W0-2t, the height H0-2t and the corner radius of the corner portion is R1. Have

From the state of FIG. 18A, the shaft pressing tools 14, 15 are press-fitted to the ends, and in the step of FIG. 18B, molding of the end of the mold release tube 11 is completed to The release element pipe 11 shown in b) can be obtained, and the sealing of the process liquid loaded with internal pressure is performed completely.

Then, the hydraulic bulge processed product 17 by the method of this invention which carried out the hydraulic bulging process by moving the axial press tools 14 and 15 further to the axial direction, raising the internal pressure of a process liquid can be obtained.

In addition, you may perform shaping | molding of the parallel part 11a, 11b of the pipe end performed before hydraulic bulging process in preforming or a previous step. It can be performed by conventional machining methods such as throttle machining, hole expansion machining, swaging machining, spinning machining, or a combination thereof.

It is a figure which shows the structural example of the axial pressing tool which also served as the sealing tool which is a structural member of the hydraulic bulge processing apparatus of this invention. 20 (a) is a structural example in the case of sealing by the end faces 14b and 15b which contact the end face of the mold release tube 11, (b) similarly protrudes 14c and 15b into the end faces 14b and 15b. Configuration example giving 15c, (c) Configuration example giving step 14d, 15d to the boundary part with the end surface 14b, 15b of parallel part 14a, 15a, (d) The parallel part 14a, The structural example which provided the O ring 18 to 15a is shown, respectively.

Any configuration example shown in FIGS. 20A to 20D satisfies the relationship between the parallel portions 14a and 15a shown in the above formulas (3) to (6) and the periphery of the tip portion.

The embodiment described above shows only one specific example of the present invention, and although the shape of the cavity of the mold bodies 12 and 13 is also of a relatively simple shape, it is naturally a three-dimensional complex represented by ordinary automobile parts. It may be a shape.

Incidentally, in the above-described embodiment, the shaft is pressed from both the small diameter side and the large diameter side, but in the present invention, it is applied to either one, and the other is conventionally performed, for example, as shown in FIG. You may employ | adopt the system without axial compression as shown. Since the effect of axial compression | variation changes with product shape, what is necessary is just to determine the application range of this invention according to the case.

In addition, although the case of the simple tapered pipe shape was mainly described in the above-mentioned embodiment as a raw material of the release small pipe 11, even if it welds by combining a simple tapered pipe shape, or when combining a taper pipe and a normal straight pipe, both ends are described. Since each can approximate a part of simple taper pipe | tube, it can apply as a raw material of the mold release tube 11 of this invention.

The release element tube for hydraulic bulge processing of this invention has the peripheral length which an outer diameter gradually increases or decreases from one side to the other in an axial direction, and forms a parallel part on at least one end side. In the processing apparatus and the processing method using this mold release pipe, parallel portions are respectively provided on the inner surface of at least one end of the upper and lower mold bodies and the outer surface of the shaft pressing tool corresponding to the inner surface of the end. The machining which combined the axial press in the axial direction is attained. As a result, in the hydraulic bulge processed product subjected to the hydraulic bulge processing, it is possible to obtain a large expansion ratio more than conventionally, and also to easily join with other parts, and to apply it to industrial machines more widely for automobiles. Can be.

Claims (7)

It is a release tube which is provided for hydraulic bulge processing, A release element for hydraulic bulge processing, having a peripheral length where the outer diameter gradually increases or decreases from one side to the other in the axial direction, and a parallel portion is formed on at least one end side. The mold release tube for hydraulic bulge processing according to claim 1, wherein the length of the parallel portion is equal to or greater than the total length of the axial compression amount performed in the hydraulic bulge processing and the length required for sealing during the hydraulic bulge processing. The mold release tube according to claim 1 or 2, which is a mold release tube provided for the manufacture of a hydraulic bulging workpiece having a rectangular cross section or a polygonal cross section, wherein the radius of curvature R of the corner portion in the parallel portion is axially direction of the pipe end portion. A release element pipe for hydraulic bulge processing, characterized by changing in response to a change in the peripheral length difference of the release element pipe corresponding to a distance. In order to hold and hold a pair of metal mold | die main body and the mold release tube of any one of Claims 1-3, the axial pressing tool which serves as the sealing tool by which the front-end part is inserted in the both ends of the said metal mold body is provided, , The injection hole of the processing liquid is provided in any one of the said shaft pressing tools, and the parallel part is provided in the inner surface of at least one end side of the said mold main body, and the outer surface of the said shaft pressing tool corresponding to this end side inner surface, respectively. Hydraulic bulge processing apparatus characterized by the above-mentioned. The axial compression amount on the small diameter portion side is δL, the axial compression amount on the large diameter portion is δL ', the length required for sealing on the small diameter portion is L0 and the length required for sealing on the large diameter portion is L0'. In one case, The length of the parallel part provided in the small diameter part side of the said mold main body is δL + L0 or more, and the length of the parallel part provided in the large diameter part side of the said mold main body is δL '+ L0' or more, and the small diameter part side of an axial press tool The length of the parallel part provided in the delta L + L0 or more, and the length of the parallel part provided in the large diameter part side of an axial pressing tool is L0 'or more, The hydraulic bulge processing apparatus characterized by the above-mentioned. After manufacturing the release element pipe of any one of Claims 1-3 using the hydraulic bulge processing apparatus of Claim 4 or 5, the hydraulic element bulge process which combined pressure-resistant load and press-fitting was performed to the said release element pipe. Bulge processing method. The releasing element pipe according to any one of claims 1 to 3 is set in a mold of the hydraulic bulge processing device according to claim 4 or 5, and the bulge processed product is subjected to a hydraulic bulge process in which a pressure-resistant load and a press fit are combined with the release element pipe. .