JP4549686B2 - Bulge forming apparatus, bulge forming method and molded product thereof - Google Patents

Description

  The present invention relates to a bulge molding apparatus, a molding method, and a molded product thereof, in which an ultra-high pressure liquid is supplied to the inside of a hollow pipe set in a mold, and the hollow pipe is deformed into a shape along the mold.

  2. Description of the Related Art Conventionally, a method for forming a motorcycle, an undercarriage part of an automobile, a gas turbine part, and the like by connecting a plurality of members by welding or the like is often employed. For example, the combustor parts of a gas turbine are cylindrical and have a shape with a changed outer diameter. Conventionally, press-molded parts divided into two parts are joined by welding or the like, or a simple cylinder is used from the inside using a mold. The tube is expanded and molded. However, it takes time for molding, and the molding cost increases. In addition, when forming by expanding the cylinder, there is a limit to the shape of the tube to be expanded, so there are cases where it is formed from a conical element tube, but in that case, the material becomes complicated and wasteful, and the element tube It takes a lot of time and cost to mold the material. Therefore, in recent years, bulge forming (hydroforming) in which these components are integrally formed from a metal pipe has attracted attention.

  FIG. 7 is a drawing showing this type of bulge forming apparatus, wherein (a) is a cross-sectional view before processing, and (b) is a cross-sectional view during processing. In this bulge forming apparatus 51, a mold 52 is divided into upper and lower parts for taking in and out the raw tube and the molded product. At the time of molding, the raw pipe 53 is inserted into the two-part mold 52 (a) and pressed downward by the clamping press 54, and then the internal pressure is applied to the inside of the raw pipe 53 with the liquid compressed by the pressure intensifier 55. By pushing in the axial direction with the shaft pushing device 56 while being applied, the base tube 53 is expanded and deformed so as to be inscribed in the mold 52, thereby obtaining a molded product 57 having a desired shape (b). As the raw tube 53 for obtaining a molded product by this bulge forming, for example, as shown in a perspective view showing an example of a raw tube used for bulge forming in FIGS. 8 (a), (b), and (c), Hollow pipes such as the pipe 59 and the preform pipe 60 are used. Since such a hollow pipe is deformed (expanded) to obtain a molded product, the molded product has no welded portion and is superior in strength and can contribute to weight reduction by reducing the plate thickness.

  In this bulge forming, a very large internal pressure load is applied to the inside of the raw tube to deform the metal, so that a force that spreads the two dies is generated by the pressure load having a very large reaction force. Therefore, as described above, the upper mold is pressed downward by the clamping press 54 so that the two-part mold 52 is not opened. The larger the shape of the molded product and the larger the required internal pressure, the greater Requires clamping force. For example, a recent mold clamping press includes a press apparatus having a mold clamping force of 50000 kN.

  As a conventional technique of this type, a pair of upper and lower molds are clamped, and tapered clamps project from the mating portions of the molds to form a tapered cross-sectional shape along the taper of these clamps. There are some which have tried to perform by the wedge action between these clamps and a clamp groove by pressing a clamp with a mold clamping block provided with the clamped groove (for example, refer to patent documents 1).

In addition, as another conventional technique, there is a technique in which a cylindrical body of a gas turbine combustor liner is formed into a corrugated shape and a corrugated shape by bulge forming using a double structure die of an inner die and an outer die. (For example, refer to Patent Document 2).
Japanese Patent Laid-Open No. 2002-35852 (pages 2 and 3 and FIGS. 2 and 3) JP-A-8-278029 (pages 2, 4 and 4)

  However, in Patent Document 1, since the two opposing surfaces of the mating portion of the planar mold are pressed and clamped, elastic deformation occurs in the mold in the axial pressing direction where the mold is not clamped. There is a risk that. Moreover, it is difficult to withstand recent high pressures. In order to avoid such deformation, the mold must be manufactured very firmly, resulting in an increase in equipment size and cost.

  Moreover, in the said patent document 2, although the double metal mold | die is shown, it is only described as the double structure, and it describes about the structure which can endure the high pressure which acts in the pipe expansion direction. It is difficult to withstand the recent high pressure.

  On the other hand, in bulge forming, as described above, in order to expand the pipe 53, it is necessary to apply axial pressing (axial compression force) to the pipe 53 along with the internal pressure. For this reason, in addition to the large clamping press 54 for pressing the mold, the bulge forming apparatus requires a shaft pressing device 56, a pressure intensifier 55, and many high pressure devices. In addition, when forming a large molded product as a high pressure device that can cope with the recent increase in pressure, all of these devices require a very large press. Therefore, a very large and expensive device is required to cope with high pressure in the conventional bulge forming device.

  This is because, in order to form a molded product having a large cylindrical shape whose outer diameter has changed, such as the combustor part of the gas turbine described above, a higher pressure clamping press, a pressing press, a hydraulic device And a larger and more expensive device is required.

Therefore, in order to solve the above-described problem, the bulge forming apparatus of the present invention is provided with an inner mold that can be divided in the horizontal direction by a vertically divided surface, and the raw tube is inserted in the vertical direction into the divided portion of the inner mold. Forming a mold part, and forming the outer surface of the inner mold in a state in which the inner mold is put together and the periphery of the mold part is in close contact with each other to form a slanted surface extending downward at a predetermined angle; A cylindrical outer mold in which an inclined surface that extends downward at an angle along the inclined surface is formed on the inner surface is provided, and the outer mold is in close contact with the outer surface of the inner mold and the inner mold is held in close contact with the inner mold. A pressure intensifier for supplying high-pressure liquid to the inside of the element pipe from the lower side of the element pipe inserted into the inner mold part is provided, and a shaft pushing device for pushing the axis from the upper side of the element pipe is provided . It is configured so that the inner surface of the suspended outer mold is brought into close contact with the outer surface of the inner mold by lowering the device. In the hanging end position outside mold is lowered to close contact with the inner mold, it is set to axial pressing before the start position from the upper side of blank tube by the shaft pressing device.

In addition, an inner mold that can be divided in the horizontal direction by a vertically divided surface is provided, and a forming mold portion for inserting a raw pipe in the vertical direction is formed in the divided portion of the inner mold, and the inner mold is combined with the forming mold. The outer surface of the inner mold in a state in which the periphery of the part is in close contact is formed on an inclined surface that extends downward at a predetermined angle, and the inclined surface that extends downward at an angle along the inclined surface of the inner mold is formed on the inner surface. The formed cylindrical outer mold is provided, and the outer mold is brought into close contact with the outer surface of the inner mold, and the inner mold is held in close contact with the inner mold. A pressure intensifier for supplying high-pressure liquid is provided inside the element pipe, a shaft pushing device for axially pushing from above the element pipe is provided, a suspension arm is provided on the upper part of the outer mold, and the suspension arm is locked. a support member that may be only set to push the shaft device.

  Furthermore, in any one of the above bulge forming apparatuses, the inclination angle of the inclined surface formed between the outer surface of the inner mold and the inner surface of the outer mold is determined by the internal pressure of the high-pressure liquid forming the element tube inserted into the inner mold. You may set to the angle used as the frictional force which an outer type | mold does not move with upward force.

  Further, in the bulge forming apparatus, a fixing member is provided for fixing the outer mold to a fixed object in a state where the inclined surface of the outer mold is brought into close contact with the inclined surface of the inner mold to prevent the inner mold from spreading, and the high-pressure liquid The outer mold may not be moved by an upward force due to the internal pressure.

  Furthermore, in any one of the above bulge forming apparatuses, if the inclined surface is formed as a conical surface, an outward force during molding can be received substantially evenly in the circumferential direction.

  Further, in any of the above bulge forming apparatuses, if the pressure intensifier is constituted by a double-acting pressure intensifier, a large amount of high-pressure liquid can be continuously supplied.

On the other hand, in the bulge forming method of the present invention, the outer surface is formed into an inclined surface that spreads downward, and the inner die is inserted into the forming die portion in the inner die that can be divided in the horizontal direction by the vertical dividing surface. The outer mold is hung and lowered by a shaft pushing device that axially pushes the outer mold from the upper side of the raw tube, with the outer mold having an inner surface formed with an inclined surface along the inner mold inclined surface on the outer surface of the inner mold. The inner end of the inner die is brought into close contact with the outer surface of the inner die to suppress the spread of the inner die, and the suspension end position where the outer die lowered by the axial pushing device comes into close contact with the inner die is viewed from the upper side of the raw tube by the axial pushing device. Is set to a position before starting the axial push of the inner pipe, and then a high pressure liquid is supplied into the raw pipe from the lower side of the raw pipe inserted into the inner mold, and an axial pushing force is applied from the upper side of the raw pipe to bring the inner pipe into the inner pipe. It is adapted to follow the mold part in the mold.

  In addition, if any of the above bulge forming devices is used to form a gas turbine part molded product by forming the outer shape into the shape of the molding part in the inner mold while applying internal pressure to the pipe-shaped element pipe of the gas turbine part, Gas turbine parts (combustors etc.) that are inexpensive even in shape can be obtained.

  The invention of the present application enables bulge forming that does not require high-pressure clamping even in the production of complicated tubular parts by the means described above, enabling large bulge forming and reducing the cost required for bulge forming. And the size of the apparatus can be reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a bulge forming apparatus according to an embodiment of the present invention. FIG. 2 is a drawing of a pressure intensifier used in the bulge forming apparatus, where (a) is a single-acting pressure intensifier and (b) is a piping diagram showing a double-acting pressure intensifier. In the drawings described below, a downwardly inclined surface formed on the inner mold and the outer mold is a conical surface, and the inclination angle is exaggerated.

  As shown in the figure, the bulge forming apparatus 1 includes an inner mold 3 (inner mold) that can be divided in a lateral direction provided on an apparatus base 2 that is a fixed object, and an outer mold that is provided on the outer periphery of the inner mold 3. A die 4 (outer die) and a shaft pushing device 6 for raising and lowering the outer die 4 and axially pushing the raw tube 5 which is a molding object inserted into the inner die 3 from above are vertically arranged. Is provided. Further, a high-pressure liquid pipe 7 for supplying high-pressure liquid into the raw pipe 5 from the lower side of the raw pipe 5 is provided at the lower part of the inner mold 3, and the high-pressure liquid pipe 7 is connected to a pressure intensifier 8. . The same technique as the conventional technique is used to supply the high-pressure liquid to the inside of the element tube 5.

  The inner mold 3 is formed of, for example, a left and right divided part, and is formed of a conical surface 9 whose outer surface is expanded in a downward direction in a close contact state. In a divided portion (center portion) obtained by dividing the inner die 3, a forming die portion 10 for bulging the hollow pipe 5 is formed.

  The outer die 4 is formed on a conical surface 11 whose inner surface is expanded downward and coincides with the conical surface of the outer surface of the inner die 3. The conical surface 11 is formed to have a diameter so as to substantially contact the lower end when inserted from above so as to follow the conical surface 9 of the inner mold 3. The conical surface 11 of the outer mold 4 preferably has a diameter that contacts at least the lower end position of the mold part 10 formed on the inner mold 3. The inner surface of the outer mold 4 is formed as a conical surface 11 along the outer surface of the inner mold 3. However, the outer surface (planar shape) may be circular or rectangular, and may be a cylinder surrounding the inner mold 3. That's fine. In this embodiment, the whole is circular and formed with substantially the same thickness, and the outward force generated when the raw tube 5 is deformed by the forming die portion 10 of the inner die 3 by the conical surface 11 formed on the inner surface is almost the same. I try to receive it evenly. A suspension arm 12 is provided on the upper part of the outer mold 4. The suspension arm 12 is provided at a plurality of locations in the circumferential direction so that the outer mold 4 can be supported in a balanced manner.

  The shaft pushing device 6 is inserted into the lower part of the expanding and contracting rod 13 through the suspension arm 12 of the outer mold 4 and the support member 14 that supports the outer mold 4 and the molding die portion 10 of the inner mold 3. A shaft pressing member 15 that applies a shaft pressing force to the raw tube 5 is provided. The support member 14 is formed in a shape corresponding to the arrangement of the suspension arm 12 provided on the outer mold 4. In this embodiment, the outer surface of the outer mold 4 is formed in a circular shape, and is formed in a disk shape so as to support the suspension arm 12 arranged in a circle so that the outer mold 4 can be supported with good balance. The shaft pressing member 15 is formed with a diameter and a length that can apply a shaft pressing force to the base tube 5 inserted into the molding die portion 10 of the inner mold 3 with a predetermined stroke. As the pressing capability of the shaft pressing device 6, for example, about 5000 kN is used. In this embodiment, the outer die 4 is moved up and down by the shaft pushing device 6, but a device for moving up and down the outer die 4 may be provided separately.

  As the pressure intensifier 8, as shown in FIGS. 2 (a) and 2 (b), a single-acting or double-acting intensifier capable of supplying a high-pressure liquid according to the diameter, processing shape, etc. of the raw tube 5 is used. The single-acting pressure intensifier 16 shown in FIG. 2 (a) sucks low-pressure liquid from a low-pressure channel 19 into a pressurizing chamber 18 provided on one side of a cylinder 17, and supplies the pressurized high-pressure liquid to the high-pressure channel 20. To be discharged. The low pressure channel 19 is provided with a check valve 21 that prevents the pressurized liquid to be discharged from returning. Therefore, the pressurized liquid is intermittently discharged from the pressurizing chamber 18 provided on one side of the cylinder 17. On the other hand, the double-acting pressure intensifier 22 shown in FIG. 2 (b) alternately sucks the low-pressure liquid from the low-pressure channel 25 into the pressurizing chambers 24 provided in both cylinders 23, and supplies the pressurized high-pressure liquid. The liquid is alternately discharged into the high-pressure channel 26. In this case, a check valve 27 is provided in the low pressure channel 25 and the high pressure channel 26 so that the pressurized liquid to be discharged does not return. Therefore, the pressurized liquid can be continuously discharged from the pressurizing chamber 24 provided in both of the cylinders 23.

  The selection of either the single-acting pressure intensifier 16 or the double-acting pressure intensifier 22 may be determined according to the pressure of the high-pressure liquid or the required flow rate. For example, when a large-sized molded product is molded with the inner mold 3 as described above, the divided part of the inner mold 3 being processed is restrained by the elastic force of the outer mold 4 as described later. When the force to spread the mold 3 is large, a gap is formed in the divided portion of the inner mold 3 due to the elastic deformation of the outer mold 4, and water leakage tends to occur from the gap toward the shaft pressing portion. For this reason, in the case of the single-acting pressure intensifier 16 that is normally used, the high-pressure water is supplied by one pressure-increasing cylinder 17, so that there are many cases where the required high-pressure water is insufficient. Therefore, by using a double-acting pressure intensifier 22 that can continuously supply high-pressure water in both directions, the supply flow rate of the high-pressure water can be increased even if leakage occurs due to a large increase in the supply flow rate of high-pressure water. Can be compensated for. That is, when molding a large molded product that requires a large amount of high-pressure liquid, the double-acting pressure intensifier 22 can be used to prevent shortage of high-pressure water.

  FIG. 3 is an explanatory view of a processing method by the bulge forming apparatus shown in FIG. 1, wherein (a) is a sectional view before fitting the inner mold, and (b) is a sectional view before lowering the outer mold. 4A and 4B are explanatory views of a processing method using the bulge forming apparatus, where FIG. 4A is a cross-sectional view of the outer mold in close contact with the inner mold, and FIG. FIG. FIG. 5 is a cross-sectional view for explaining the relationship between the contact surfaces of the outer mold and the inner mold in the bulge forming apparatus. The bulge forming method by the bulge forming apparatus 1 described above will be described below with reference to these drawings. In addition, the same code | symbol is attached | subjected to the structure shown in FIG. 1 mentioned above, and the description is abbreviate | omitted.

  First, as shown in FIG. 3 (a), a two-part inner mold 3 is provided on the apparatus base 2 in a state where the lower part is widened, and a blank tube is formed in a mold part 10 formed at the center of the inner mold 3. 5 is inserted.

  Next, as shown in FIG. 3 (b), after aligning the inner die 3, the rod 13 of the shaft pushing device 6 is extended to lower the outer die 4 from above the inner die 3. At this time, the suspension arm 12 provided on the upper part of the outer mold 4 is locked by the support member 14 provided on the shaft pushing device 6, and the weight of the outer mold 4 is passed through the suspension arm 12. It is supported by a shaft pushing device 6. In this embodiment, the outer die 4 is configured to be moved up and down by the shaft pushing device 6. However, since the shaft pushing device 6 only needs to support the weight of the outer die 4, the shaft pushing device 6 is increased in size. There is no.

  Next, as shown in FIG. 4 (a), the outer die 4 is lowered by the shaft pushing device 6 while keeping the inner peripheral surface of the outer die 4 along the outer peripheral surface of the inner die 3. At this time, since the inclination of the outer surface of the inner mold 3 and the inclination of the inner surface of the outer mold 4 are formed substantially the same, the center of the outer mold 4 is lowered so as to coincide with the center of the inner mold 3. In this way, the outer shape of the inner mold 3 divided into two is conically spread downward (side view is “wedge-shaped” or “tapered”), and the inner mold 3 has a hollow outer surface and a conical inner surface. By covering the outer mold 4, it can be a means for fixing the split surface of the inner mold 3 so as not to open at the time of molding by the weight of the outer mold 4 and the frictional force between the conical surfaces 9, 11. A mold clamping press can be dispensed with. That is, the wedge effect is produced by the conical surfaces 9 and 11 (inclined surfaces) spreading downward, and the inner mold 3 can be clamped. At this time, since the outer peripheral surface of the inner mold 3 and the inner peripheral surface of the outer mold 4 are formed in the conical surfaces 9 and 11 having the same shape, the outer mold 4 is automatically adjusted so that the axes are aligned. The entire circumference of the inner mold 3 can be tightened almost uniformly (in this figure, the tightening of the inner mold 3 by the outer mold 4 is not completed).

  Then, as shown in FIG. 4 (b), the rod 13 of the shaft pushing device 6 is further extended to lower the outer die 4, and the inner surface (conical surface 11) of the outer die 4 is the outer surface (conical surface) of the inner die 3. When it reaches the suspension end position (the position of the outer mold 4 shown in FIG. 4 (b)) where it comes into close contact with the surface 9) and stops descending under its own weight, the inner mold 3 is tightened from the outer periphery by the weight of the outer mold 4 The divided surfaces are brought into close contact with each other and are integrally held. Thereafter, a high pressure liquid is supplied from the intensifier 8 to the inside of the raw tube 5 to give a yielding internal pressure, and a shaft pushing member 15 of the shaft pushing device 6 gives a shaft pushing force from above the elementary tube 5. In the case of this embodiment, the inner mold 3 can be clamped by the outer mold 4 and the shaft 5 can be pressed continuously.

As shown in FIG. 5, the contact surface relationship between the outer mold 4 and the inner mold 3 at this time is that a large force Fp is applied from the inner mold 3 to the outer mold 4 by the high-pressure liquid supplied to the inside of the raw tube 5. Although acting, since the conical surface 9 of the outer surface of the inner mold 3 and the conical surface 11 of the outer mold 4 are in close contact, the outer mold 4 is more than the upward force Fz for moving the outer mold 4 upward. The self-weight W and the frictional force of the conical surfaces 9 and 11 are larger, and the outer die 4 does not move, and the force to spread the inner die 3 is suppressed by the elastic force of the outer die 4. It is. That is, in this embodiment, since the inclination angle θ (taper angle) of the conical surfaces 9 and 11 in contact with both molds 3 and 4 is small, the force that the inner mold 3 tries to spread by the internal pressure load is the weight of the outer mold 4. In this state, the inner tube 5 is further loaded with an internal pressure and axially pushed, so that the tube 5 expands greatly. Is inscribed in the mold part 10. Thereafter, by applying a larger internal pressure, the portion not in contact with the mold part 10 (mold), such as a corner of a rectangular cross section, is expanded, and the entire surface of the base pipe 5 is inscribed in the mold part 10 for the purpose. A molded product 28 can be obtained.

  In addition, in this embodiment, as described above, it is possible to stabilize the inner mold 3 from spreading during molding by the frictional force of the conical surfaces 9 and 11 in contact with both molds 3 and 4 and the weight of the outer mold 4. Therefore, it is possible to easily mold a large molded article 28 (for example, a large part such as a combustor of a gas turbine). In addition, since the two types of operations of clamping the inner die 3 and pushing the shaft by the outer die 4 are performed by one shaft pushing device 6 (pressing machine), the pressing machine removes the shaft pushing and the outer die 4 from each other. A press with a relatively small output that can be performed is better.

  In the case of this embodiment, since the conical surfaces 9 and 11 (contact surfaces) are in close contact with each other with a small inclination angle θ, a large force is required for lifting the outer die 4 to remove it from the inner die 3. That is, in the case of this example, since the inner mold 3 is tightened by the outer mold 4 due to the small angle θ of the conical surfaces 9 and 11, removal of the outer mold 4 after molding is an upward force by the shaft pushing device 6. Is required.

The bulge forming method shown in FIG. 4 (b) is preferably carried out in the following three forming regions.
1. The initial forming zone internal pressure is a pressure at which the base tube 5 yields. The axial push amount is the amount of free contraction of the tube 5 accompanying the expansion of the tube 5. In this initial forming region, the amount of increase in internal pressure is large, and the amount of increase in axial push is small.
2. The tube is expanded until it comes into contact with the inner die 3 while increasing the thickness of the expanded portion by pushing the shaft just before buckling occurs so that no burst occurs in the intermediate forming region and the final forming region. The internal pressure should be less than the burst pressure. In this intermediate forming zone, the increase in internal pressure is small and the increase in axial push is large.
3. A predetermined internal pressure is applied from a required corner radius of curvature in order to secure the final molded area product shape. The axial push amount is set to a slight amount because the friction is large due to the increase in internal pressure and the effect of increasing the wall thickness of the expanded portion is small. In this final forming zone, the amount of increase in internal pressure is large, and the amount of increase in axial push is small.

  According to such a bulge forming method, it is possible to perform mold clamping that requires a very large force evenly over the entire circumference only by the weight of the outer mold 4 and the frictional force of the conical surfaces 9 and 11. The spread of the inner mold 3 can be stably suppressed without requiring a press machine or the like. This eliminates the need for a high-pressure device required for clamping, and allows a large molded product to be processed with a small bulge forming device, thereby reducing the size of the bulge forming device 1 and reducing the cost required for the device.

  In addition, since a large force is not required for clamping, a large product can be molded even with a small shaft pressing device 6 (for example, a pressing machine having a pressing force of about 5000 kN). For example, by manufacturing a gas turbine part, a complicated shape can be integrally formed, the number of parts can be reduced, assembly processes such as welding can be greatly reduced, and production time and cost of the product can be greatly reduced. In addition, since a complicated shape is integrally formed from a simple cylinder, the material yield is improved, the material is not wasted, and the material cost can be reduced.

  FIG. 6 is a cross-sectional view for explaining the relationship between contact surfaces different from the contact surface relationship between the outer mold and the inner mold shown in FIG. In addition, the same code | symbol is attached | subjected to the structure same as the structure shown in FIG. 1 mentioned above, and the description is abbreviate | omitted. In this example, the contact surface when the inclination angle θ (taper angle) of the outer surface of the inner die 29 and the inclination angle θ (taper angle) of the inner surface of the outer die 30 are larger than the angle shown in FIG. 4 described above. It is an example which shows the relationship.

  As shown in the figure, when the inclination angle θ at which the conical surface 31 of the outer surface of the inner die 29 and the conical surface 32 of the inner surface of the outer die 30 contact each other increases, the internal pressure load acting on the element tube 5 inserted into the inner die 29 increases. The upward force Fz generated between the inner mold 29 and the outer mold 30 is increased, and depending on the size of the internal pressure load, the outer mold 30 may be moved upward to prevent the inner mold 29 from spreading. That is, when the inclination angle θ is large, the force that the inner mold 29 spreads due to the internal pressure load may not be supported only by the self weight W of the outer mold 30 and the frictional force between the conical surfaces 31 and 32 (contact surfaces). . For this reason, in this case, a fixing force for fixing the position of the outer mold 30 is required.

  In the illustrated example, after the outer periphery of the inner mold 29 is fastened with the outer mold 30, the outer mold 30 is fixed to the device base 2, which is a fixed object, by a fixing member 33. As the fixing member 33, it is only necessary to fix the movement of the outer mold 30. Therefore, the fixing member 33 is fixed to the apparatus base 2 by a bolt 34 which is a general fixing means.

  In the case of this example, since the inclination angle θ of the conical surfaces 9 and 11 is increased, the inner die 29 is hardly tightened by the outer die 30. Therefore, the removal of the outer die 30 after molding acts on an internal pressure load. The outer mold 30 can be easily removed from the inner mold 29 by lifting it.

  As a method of determining the inclination angle θ, it may be determined under the following conditions. When the inclination angle θ> 0 °, the force Fp acting on the outer molds 4 and 30 from the inner molds 3 and 29 is Fp = P × A (P: internal pressure, A: internal pressure projected area). An upward force Fz acting between the inner molds 3 and 29 and the outer molds 4 and 30 is Fz = Fp · sin θ. On the other hand, the downward force acting between the inner molds 3 and 29 and the outer molds 4 and 30 is caused by the weight W of the outer molds 4 and 30 and between the inner molds 3 and 29 and the outer molds 4 and 30. Μ · Fp · cos θ (μ; friction coefficient).

  Therefore, the size of the raw tube 5, the size of the internal pressure for processing the raw tube 5, the material of the inner dies 3, 29 and the outer dies 4, 30, the dead weight of the outer dies 4, 30 and the ease of removing the outer dies 4, 30 It may be determined from the relationship between the forces in consideration of the above conditions. For example, depending on the conditions, if the inclination angle θ is about 5 ° to 7 °, the outer molds 4 and 30 are lifted. Therefore, in the case where the outer molds 4 and 30 are not lifted, the inclination angle θ is It is set to about 1 ° to 2 °.

  In the above-described embodiment, the two-divided inner molds 3 and 29 have been described as an example. However, the inner molds 3 and 29 are described above as long as the inner pipe 3 and 29 can be inserted and the molded product can be taken out. It is not limited to the embodiment.

In the above-described embodiment, the inclined surface is formed by the conical surfaces 9 and 11, but the conical surfaces 9 and 11 may be polygonal pyramid surfaces or the like.
Although the outer mold 4 is lifted and lowered by the shaft pushing device 6, a device for lifting and lowering the outer mold 4 may be provided separately.

  Further, the above-described embodiment shows an example of the best embodiment, and various modifications can be made without departing from the gist of the present invention, and the present invention is not limited to the above-described embodiment. .

  The bulge forming apparatus according to the present invention is useful in bulge forming that requires high-pressure clamping, such as production of parts such as motorcycles, automobiles, and gas turbines, and other parts having complicated tubular shapes.

It is sectional drawing which shows the bulge forming apparatus which concerns on one Embodiment of this invention. It is drawing of the pressure booster used for the bulge shaping | molding apparatus shown in FIG. 1, (a) is a single acting type pressure booster, (b) is a piping diagram which shows a double acting type pressure booster. It is explanatory drawing of the processing method by the bulge forming apparatus shown in FIG. 1, (a) is sectional drawing before match | combining an inner type | mold, (b) is sectional drawing before lowering an outer type | mold. It is explanatory drawing of the processing method by the bulge shaping | molding apparatus shown in FIG. FIG. It is sectional drawing for demonstrating the relationship of the contact surface of the outer type | mold and inner type | mold in the bulge forming apparatus of this invention. It is sectional drawing for demonstrating the relationship of the contact surface different from the relationship of the contact surface of the outer mold | type shown in FIG. It is drawing which shows the conventional bulge forming apparatus, (a) is sectional drawing before a process, (b) is sectional drawing in the middle of a process. (a), (b), (c) is a perspective view which shows the example of the raw tube used for bulge forming.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Bulge forming apparatus 2 ... Apparatus stand 3 ... Inner mold 4 ... Outer mold 5 ... Elementary pipe 6 ... Shaft pushing apparatus 7 ... High pressure liquid piping 8 ... Intensifier 9 ... Conical surface (inclined surface)
10 ... Mold part 11 ... Conical surface (inclined surface)
DESCRIPTION OF SYMBOLS 12 ... Suspension arm 13 ... Rod 14 ... Support member 15 ... Shaft pushing member 16 ... Single-acting pressure intensifier 17 ... Cylinder 18 ... Pressurizing chamber 19 ... Low pressure channel 20 ... High pressure channel 21 ... Check valve 22 ... Duplex Dynamic pressure intensifier 23 ... Cylinder 24 ... Pressure chamber 25 ... Low pressure channel 26 ... High pressure channel 27 ... Check valve 28 ... Molded product 29 ... Inner mold 30 ... Outer mold 31 ... Conical surface 32 ... Conical surface 33 ... Fixed Member 34 ... Bolt

Claims (8)

An inner mold that can be divided in the horizontal direction on a vertically divided surface is provided, a forming mold part for inserting the raw pipe in the vertical direction is formed in the divided part of the inner mold, and the inner mold is combined to form the mold part The outer surface of the inner mold in a state in which the periphery is in close contact is formed as an inclined surface that extends downward at a predetermined angle, and the inclined surface that extends downward at an angle along the inclined surface of the inner mold is formed on the inner surface. A cylindrical outer mold is provided, and the raw pipe is inserted from the lower side of the raw pipe inserted into the forming mold portion of the inner mold in a state where the outer mold is held in close contact with the outer surface of the inner mold. A pressure intensifier for supplying high pressure liquid is provided inside, and a shaft pushing device for pushing the shaft from above the raw tube is provided ,
The inner surface of the outer mold suspended by lowering the shaft pushing device is configured to be in close contact with the outer surface of the inner mold, and the suspension end position where the outer mold lowered by the shaft pushing device is in close contact with the inner mold, A bulge forming device set to a position before the shaft pressing starts from the upper side of the raw pipe by the shaft pressing device. An inner mold that can be divided in the horizontal direction on a vertically divided surface is provided, a forming mold part for inserting the raw pipe in the vertical direction is formed in the divided part of the inner mold, and the inner mold is combined to form the mold part The outer surface of the inner mold in a state in which the periphery is in close contact is formed as an inclined surface that extends downward at a predetermined angle, and the inclined surface that extends downward at an angle along the inclined surface of the inner mold is formed on the inner surface. A cylindrical outer mold is provided, and the raw pipe is inserted from the lower side of the raw pipe inserted into the forming mold portion of the inner mold in a state where the outer mold is held in close contact with the outer surface of the inner mold. A pressure intensifier for supplying high pressure liquid is provided inside, and a shaft pushing device for pushing the shaft from above the raw tube is provided,
The outer mold of the upper part provided with hanging arms, set Ketaba distearate molding apparatus support members for locking the the hanging down arm press the shaft device.   Friction force that prevents the outer mold from moving by the upward force of the internal pressure of the high-pressure liquid that forms the raw pipe inserted into the inner mold with the inclination angle of the inclined surface formed between the outer surface of the inner mold and the inner surface of the outer mold. The bulge forming apparatus according to claim 1, wherein the bulge forming apparatus is set to an angle that satisfies   The bulge molding according to claim 1 or 2, further comprising a fixing member for fixing the outer mold to a fixed object in a state where the outer mold inclined surface is brought into close contact with the inner mold inclined surface to prevent the inner mold from spreading. apparatus.   The bulge forming apparatus according to any one of claims 1 to 4, wherein the inclined surface is a conical surface.   The bulge forming apparatus according to any one of claims 1 to 5, wherein the intensifier is a double-acting intensifier. The outer surface is formed into an inclined surface that spreads downward, and the inner die is brought into close contact by inserting a blank tube into the molding die in the inner die that can be divided in the horizontal direction by a vertically divided surface,
The inner surface of the outer mold is hung and lowered by a shaft pushing device that pushes the inner mold from the upper side of the element pipe on the outer surface of the inner mold by forming an inclined surface along the inclined surface of the inner mold on the inner surface. The inner mold is kept in close contact with the outer surface of the inner mold to prevent the inner mold from spreading,
The suspension end position where the outer die lowered by the shaft pushing device is in close contact with the inner die is set to a position before the shaft pushing from the upper side of the raw tube by the shaft pushing device , and then inserted into the inner die. A bulge forming method in which a high pressure liquid is supplied from the lower side of the raw tube to the axial direction and a shaft pressing force is applied from the upper side of the raw tube to cause the raw tube to follow the forming die portion in the inner die. A molded product of a gas turbine part in which an outer shape is molded into a shape of a molding die in an inner mold while applying an internal pressure to a pipe-shaped element pipe of the gas turbine part by the bulge forming apparatus according to any one of claims 1 to 6. .

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