MOLDING DEVICE

A molding device that heats a metal material and performs quenching and that molds a plurality of components having shapes different from each other in one time of molding with respect to one metal material.

BACKGROUND

Technical Field

A certain embodiment of the present disclosure relates to a molding device.

Description of Related Art

In the related art, a device described in the related art is known as a molding device that molds a metal material. The molding device molds a plate-shaped member into a component having a desired shape by pressing the member.

SUMMARY

According to an aspect of the present disclosure, there is provided a molding device that heats a metal material and performs quenching and that molds a plurality of components having shapes different from each other in one time of molding with respect to one metal material.

According to another aspect of the present disclosure, there is provided a molding device that performs expansion molding by supplying a fluid to a metal material and that molds a plurality of components having shapes different from each other in one time of molding with respect to one metal material.

DETAILED DESCRIPTION

The component molded by the molding device described above is used in order to construct a predetermined structure. Therefore, it is required for the molding device to mold a plurality of components by performing a plurality of times of pressing. However, in a case where the number of components of the structure increases, a problem of an increase in man-hours arises since the number of times of pressing increases.

Therefore, it is desirable to provide a molding device that can reduce man-hours for manufacturing a plurality of components.

The molding device is the molding device that performs molding by heating the metal material and performing quenching. The molding device molds the plurality of components having shapes different from each other in one time of molding with respect to the one metal material. For this reason, the molding device can mold the plurality of components at once only by performing one time of molding with respect to the one metal material. For this reason, man-hours for manufacturing the plurality of components can be reduced.

The molding device is the molding device that performs expansion molding by supplying the fluid to the metal material. The molding device molds the plurality of components having shapes different from each other in one time of molding with respect to the one metal material. For this reason, the molding device can mold the plurality of components at once only by performing one time of molding with respect to the one metal material. For this reason, man-hours for manufacturing the plurality of components can be reduced.

The molding device may mold a component having a closed section as the component. In this case, the number of components can be reduced compared to a case of forming a structure in which a plurality of components are combined.

The molding device may mold a long first component and a second component and a third component, which are on both sides of the first component in a longitudinal direction, as the plurality of components. Accordingly, as the long first component is molded, the second component and the third component can be added to both sides thereof in the longitudinal direction and be molded.

The molding device may have differential strength between one component and another component of the plurality of components. Accordingly, strength is easily adjusted according to use of each component.

Hereinafter, a preferred embodiment of a molding device according to the present disclosure will be described with reference to the drawings. In each drawing, the same reference signs will be assigned to the same portions or equivalent portions, and redundant description thereof will be omitted.

FIG.1is a schematic configuration view of a molding device1according to the present embodiment. As shown inFIG.1, the molding device1is a device that molds a metal pipe having a hollow shape by blow forming. In the present embodiment, the molding device1is provided on a horizontal plane. The molding device1includes a molding die2, a drive mechanism3, a holding unit4, a heating unit5, a fluid supply unit6, a cooling unit7, and a control unit8. In the present specification, a metal pipe material40(metal material) refers to a hollow article before the completion of molding by the molding device1. The metal pipe material40is a steel-type pipe material that can be quenched. In addition, in a horizontal direction, a direction in which the metal pipe material40extends during molding is called a “longitudinal direction”, and a direction perpendicular to the longitudinal direction is called a “width direction” in some cases.

The molding die2is a die that molds the metal pipe material40into a metal pipe140and includes a lower die11and an upper die12that face each other in an up-down direction. The lower die11and the upper die12are configured by blocks made of steel. Each of the lower die11and the upper die12is provided with a recessed part in which the metal pipe material40is accommodated. In a state where the lower die11and the upper die12are in close contact with each other (die closed state), respective recessed parts form a space having a target shape, into which the metal pipe material is to be molded. Therefore, surfaces of the respective recessed parts become forming surfaces of the molding die2. The lower die11is fixed to a base stage13via a die holder or the like. The upper die12is fixed to a slide of the drive mechanism3via a die holder or the like.

The drive mechanism3is a mechanism that moves at least one of the lower die11and the upper die12. InFIG.1, the drive mechanism3has a configuration of moving only the upper die12. The drive mechanism3includes a slide21that moves the upper die12such that the lower die11and the upper die12are joined together, a pull-back cylinder22that is an actuator which generates a force for pulling the slide21upward, a main cylinder23that is a drive source which downward-pressurizes the slide21, and a drive source24that applies a driving force to the main cylinder23.

The holding unit4is a mechanism that holds the metal pipe material40disposed between the lower die11and the upper die12. The holding unit4includes a lower electrode26and an upper electrode27that hold the metal pipe material40on one end side in the longitudinal direction of the molding die2and a lower electrode26and an upper electrode27that hold the metal pipe material40on the other end side in the longitudinal direction of the molding die2. The lower electrodes26and the upper electrodes27on both sides in the longitudinal direction hold the metal pipe material40with vicinities of end portions of the metal pipe material40sandwiched therebetween from the up-down direction. Groove portions having a shape corresponding to an outer peripheral surface of the metal pipe material40are formed in upper surfaces of the lower electrodes26and lower surfaces of the upper electrodes27. Drive mechanisms (not shown) are provided in the lower electrode26and the upper electrode27and are movable independently of each other in the up-down direction.

The heating unit5heats the metal pipe material40. The heating unit5is a mechanism that heats the metal pipe material40by energizing the metal pipe material40. The heating unit5heats the metal pipe material40in a state where the metal pipe material40is separated apart from the lower die11and the upper die12between the lower die11and the upper die12. The heating unit5includes the lower electrodes26and the upper electrodes27on both sides in the longitudinal direction described above and a power supply28that causes a current to flow to the metal pipe material40via the electrodes26and27. The heating unit may be disposed in a preceding process of the molding device1and may perform heating externally.

The fluid supply unit6is a mechanism for supplying a high-pressure fluid into the metal pipe material40held between the lower die11and the upper die12. The fluid supply unit6supplies the high-pressure fluid into the metal pipe material40that has been brought into a high-temperature state by being heated by the heating unit5and expands the metal pipe material40. The fluid supply units6are provided on both end sides of the molding die2in the longitudinal direction. The fluid supply units6each include a nozzle31that supplies a fluid from opening portions of the end portions of the metal pipe material40to an inside of the metal pipe material40, a drive mechanism32that moves the nozzle31to advance and retreat with respect to the opening portions of the metal pipe material40, and a supply source33that supplies the high-pressure fluid into the metal pipe material40via the nozzle31. The drive mechanism32brings the nozzle31into close contact with the end portion of the metal pipe material40in a state where a sealing property is secured during fluid supply and exhaust and separates the nozzle31from the end portion of the metal pipe material40at other times. The fluid supply unit6may supply a gas such as high-pressure air and an inert gas as the fluid. In addition, the fluid supply unit6may be the same device including the holding unit4that includes a mechanism which moves the metal pipe material40in the up-down direction and the heating unit5.

Components of the holding unit4, the heating unit5, and the fluid supply unit6may be configured as a unitized heating and expanding unit150.FIG.2Ais a schematic side view showing the heating and expanding unit150.FIG.2Bis a sectional view showing a state where the nozzle31has sealed the metal pipe material40.

As shown inFIG.2A, the heating and expanding unit150includes the lower electrodes26and upper electrodes27, which are described above, an electrode mounting unit151on which each of the electrodes26and27is mounted, the nozzle31and the drive mechanism32, which are described above, a lifting and lowering unit152, and a unit base153. The electrode mounting unit151includes a lifting and lowering frame154and electrode frames156and157. The electrode frames156and157function as a part of a drive mechanism60that supports and moves each of the electrodes26and27. The drive mechanism32drives the nozzle31and lifts and lowers together with the electrode mounting unit151. The drive mechanism32includes a piston61that holds the nozzle31and a cylinder62that drives the piston. The lifting and lowering unit152includes a lifting and lowering frame base64that is attached to an upper surface of the unit base153and a lifting and lowering actuator66that applies a lifting and lowering operation to the lifting and lowering frame154of the electrode mounting unit151by the lifting and lowering frame base64. The lifting and lowering frame base64includes guide portions64aand64bthat guide the lifting and lowering operation of the lifting and lowering frame154with respect to the unit base153. The lifting and lowering unit152functions as a part of the drive mechanism60of the holding unit4. The heating and expanding unit150includes a plurality of unit bases153of which upper surfaces have different inclination angles and is allowed to collectively change and adjust inclination angles of the lower electrode26, the upper electrode27, the nozzle31, the electrode mounting unit151, the drive mechanism32, and the lifting and lowering unit152by replacing the unit bases153.

The nozzle31is a cylindrical member into which the end portion of the metal pipe material40can be inserted. The nozzle31is supported by the drive mechanism32such that a center line of the nozzle31matches a reference line SL1. An inner diameter of a feed port31aat an end portion of the nozzle31on a metal pipe material40side substantially matches an outer diameter of the metal pipe material40after expansion molding. In this state, the nozzle31supplies a high-pressure fluid from an internal flow path63to the metal pipe material40. Examples of the high-pressure fluid include a gas.

Returning toFIG.1, the cooling unit7is a mechanism that cools the molding die2. By cooling the molding die2, the cooling unit7can rapidly cool the metal pipe material40when the expanded metal pipe material40has come into contact with the forming surface of the molding die2. The cooling unit7includes a flow path36formed inside the lower die11and the upper die12and a water circulation mechanism37that supplies cooling water to the flow path36and that circulates the cooling water.

The control unit8is a device that controls the entire molding device1. The control unit8controls the drive mechanism3, the holding unit4, the heating unit5, the fluid supply unit6, and the cooling unit7. The control unit8repeatedly performs an operation of molding the metal pipe material40with the molding die2.

Specifically, the control unit8controls, for example, a transport timing from a transport device such as a robot arm to dispose the metal pipe material40between the lower die11and the upper die12in an open state. Alternatively, a worker may manually dispose the metal pipe material40between the lower die11and the upper die12. In addition, the control unit8controls an actuator or the like of the holding unit4such that the metal pipe material40is supported by the lower electrodes26on both sides in the longitudinal direction and then the upper electrodes27are lowered to sandwich the metal pipe material40. In addition, the control unit8controls the heating unit5to energize and heat the metal pipe material40. Accordingly, a current in an axial direction flows through the metal pipe material40, and an electric resistance of the metal pipe material40itself causes the metal pipe material40itself to generate heat due to Joule heat.

The control unit8controls the drive mechanism3to lower the upper die12and to bring the upper die12close to the lower die11, closing the molding die2. Meanwhile, the control unit8controls the fluid supply unit6to seal the opening portions of both ends of the metal pipe material40and to supply a fluid with the nozzle31. Accordingly, the metal pipe material40softened by heating expands and comes into contact with the forming surface of the molding die2. Then, the metal pipe material40is molded to follow the shape of the forming surface of the molding die2. In a case of forming a metal pipe with a flange, after a part of the metal pipe material40has entered a gap between the lower die11and the upper die12, die closing is further performed to crush the entered portion to become a flange portion. When the metal pipe material40comes into contact with the forming surface, quenching of the metal pipe material40is performed by being rapidly cooled with the molding die2cooled by the cooling unit7.

Procedures of molding of the molding device1will be described with reference toFIGS.3A and3B. As shown inFIG.3A, the control unit8performs blow forming by closing the molding die2and supplying a fluid to the metal pipe material40with the fluid supply unit6(primary blow). In the primary blow, the control unit8molds a pipe portion43in a main cavity portion MC configured by a groove portion47of each of the dies11and12and causes a portion corresponding to a flange portion44to enter a sub-cavity portion SC. Then, as shown inFIG.3B, the control unit8molds the flange portion44by further closing the molding die2and further crushing the portion that has entered the sub-cavity portion SC. Next, the control unit8performs die opening by lifting the upper die12to separate the upper die12from the metal pipe material40. Accordingly, a molding product41is molded.

Next, what type of molding product41can be molded by the molding device1according to the present embodiment will be described. The molding device1is the molding device1that heats the metal pipe material40(metal material) and that performs quenching and can mold a plurality of components in one time of molding with respect to one metal pipe material40. In addition, the molding device1is the molding device1that performs expansion molding by supplying a fluid to the metal pipe material40(metal material) and can mold a plurality of components in one time of molding with respect to one metal pipe material40. One time of molding is a series of processes from the setting of a new metal pipe material40at the molding device1to molding of the molding product41. In the molding device1according to the present embodiment, a series of processes including disposition, heating, and expansion molding of the metal pipe material40described above in the die12correspond to one time of molding. One metal material is a material made of a metal in a state of continuously extending without being cut in the middle.

The molding product41will be described with reference toFIG.4A. Molding a plurality of components in one time of molding with respect to one metal pipe material40means that a plurality of components are included in the molding product41. Before cutting of the molding product41, the plurality of components are in a state of being connected to each other as one and the same member. In the example shown inFIG.4A, the molding device1molds a long first component50and a second component51and a third component52on both sides of the first component50in the longitudinal direction. The second component51is provided on one end side of the molding product41in the longitudinal direction. An electrode portion53held by an electrode of the heating unit5is formed at a position farthest to the one end side of the molding product41. A gradual change portion56A is formed between the electrode portion53and the second component51. A gradual change portion56B is formed between the second component51and the first component50. The third component52is provided on the other end side of the molding product41in the longitudinal direction. An electrode portion54held by an electrode of the heating unit5is formed at a position farthest to the other end side of the molding product41. A gradual change portion57A is formed between the electrode portion54and the third component52. A gradual change portion57B is formed between the third component52and the first component50. The gradual change portions56A,56B,57A, and57B are portions of which a shape gradually changes by being formed between respective parts having a unique shape.

A boundary portion of each portion of the molding product41is cut through laser processing or the like. Accordingly, the first component50, the second component51, and the third component52can be treated as one independent component.

Since the entire molding product41is a tubular member, the components50,51, and52have a closed section. That is, the molding device1molds the components50,51, and52having a closed section as components.

FIG.4Bis a schematic top view showing the lower die11for molding the molding product41described above. The upper die12also has a configuration for the same effect. As shown inFIG.4B, the groove portion47of the die11includes a gradual change molding portion76A, a second component molding portion71, a gradual change molding portion76B, a first component molding portion70, a gradual change molding portion77B, a third component molding portion72, and a gradual change molding portion77A with positions and shapes corresponding to the gradual change portion56A, the second component51, the gradual change portion56B, the first component50, the gradual change portion57B, the third component52, and the gradual change portion57A of the molding product41.

The molding device1may have differential strength between one component and another component of a plurality of components. For example, the molding device1may have differential strength by making the strength of the first component50higher than those of the second component51and the third component52. As a method of providing differential strength, the molding device1may perform molding such that quenching is performed with respect to a component having high strength and quenching is not performed with respect to a component having low strength. For example, the cooling unit7(seeFIG.1) of the molding device1may keep the temperature of a forming surface in a cooling region CE including the first component molding portion70at a temperature at which quenching can be performed with respect to the molding product41and keep temperatures of forming surfaces in other regions at a temperature at which quenching cannot be performed with respect to the molding product41. For example, the cooling unit7may flow a sufficient amount of cooling water in the cooling region CE and may not flow cooling water in other regions (alternatively, a die temperature is raised by separately embedding a heater or the like to the extent that quenching does not occur, and a cooling speed at which quenching does not occur is secured). In this case, while forming surfaces of the second component molding portion71and the third component molding portion72do not perform quenching with respect to the second component51and the third component52, a forming surface of the first component molding portion70performs quenching with respect to the first component50.

Next, further specific examples of components molded by the molding device1will be described with reference toFIGS.5to8.FIG.5is a view showing a specific example of the molding product41.FIG.6is an enlarged perspective view of the other end portion of the molding product41. As shown inFIG.5, the molding device1molds a bumper beam80as the first component50. In addition, the molding device1molds a crush tube81as the second component51and molds a crush tube82as the third component52. Since the long bumper beam80has a gently curved shape, the molding product41has a shape gently curved shape as a whole. Therefore, the electrode portions53and54are inclined downward toward an outer side in the longitudinal direction. Therefore, the heating and expanding unit150inclines the nozzle31and the electrodes26and27in accordance with such electrode portions53and54(seeFIGS.2A and2B).

The bumper beam80and the crush tube82are components configuring a front bumper100of a vehicle shown inFIG.7. The front bumper100includes, at a front end portion of the vehicle, the bumper beam80that extends in a vehicle width direction in a state of being curved to be convex forward. In a case where the vehicle has collided from the front, the bumper beam80is a member that receives a load from the front. The front bumper100includes the crush tubes81and82provided at the rear of both end portions of the bumper beam80in the vehicle width direction. The crush tubes81and82are members that absorb the load by being crushed and that transmit the load to a skeletal structure on the rear side of the vehicle when the bumper beam has received the load. In addition, the front bumper100includes base plates83and84provided to spread in the up-down direction at rear ends of the crush tubes81and82, respectively.

As shown inFIG.9, the bumper beam80includes a front wall portion80a, a rear wall portion80b, an upper wall portion80c, and a lower wall portion80d. Since the bumper beam80is molded by the molding device1described above, materials for portions connecting the front wall portion80a, the rear wall portion80b, the upper wall portion80c, and the lower wall portion80dto each other are continuous without being cut. That is, the bumper beam80is configured as one component having a closed section structure in which the front wall portion80a, the rear wall portion80b, the upper wall portion80c, and the lower wall portion80dare integrated. In the front wall portion80a, a plurality of (herein, three) beads86are provided at different positions in the up-down direction. The beads86extend in a longitudinal direction of the bumper beam80, that is, the vehicle width direction (seeFIG.8).

As shown inFIG.8, the crush tubes81and82are tubular members extending in a front-rear direction. The crush tubes81and82are disposed in a posture in which the crush tubes81and82are open at a front end and a rear end. The crush tubes81and82include side wall portions81aand82aon an outer side in the vehicle width direction, side wall portions81band82bon an inner side in the vehicle width direction, upper wall portions81cand82c, and lower wall portions81dand82d. Since the crush tubes81and82are molded by the molding device1described above, materials for portions connecting the side wall portions81aand82a, the side wall portions81band82b, the upper wall portions81cand82c, and the lower wall portions81dand82dto each other are continuous without being cut. That is, the crush tubes81and82each are configured as one component having a closed section structure in which the side wall portions81aand82a, the side wall portions81band82b, the upper wall portions81cand82c, and the lower wall portions81dand82dare integrated. The bumper beam80is set to have high material strength as quenching is performed. On the contrary, the crush tubes81and82are provided to have differential strength such that material strength is lower than that of the bumper beam80as quenching is not performed. Therefore, the crush tubes81and82can absorb a load by being crushed well.

As shown inFIG.6, in a state of the molding product41, a place corresponding to an end portion of the bumper beam80in the vehicle width direction and a place corresponding to an end portion of the crush tube82in the front-rear direction are disposed to face each other in the longitudinal direction, and both are connected to each other by the gradual change portion57B. The gradual change portion57B gradually changes from the shape of the end portion of the bumper beam80to the shape of the end portion of the crush tube82. In addition, the place corresponding to the end portion of the crush tube82in the front-rear direction and the end portion of the electrode portion54are disposed to face each other in the longitudinal direction, and both are connected to each other by the gradual change portion57A. The gradual change portion57A gradually changes from the shape of the end portion of the crush tube82to an annular shape of the end portion of the electrode portion54. An end portion of the molding product41on an opposite side (crush tube81) also has a configuration for the same effect.

Next, operations and effects of the molding device1according to the present embodiment will be described.

The molding device1according to the present embodiment is the molding device1that heats the metal pipe material40(metal material) and that performs quenching and molds a plurality of components in one time of molding with respect to one metal pipe material40.

The molding device1is the molding device1that performs molding by heating the metal pipe material40and performing quenching. The molding device1molds a plurality of components in one time of molding with respect to one metal pipe material40. For this reason, the molding device1can mold the plurality of components at once only by performing one time of molding with respect to the one metal pipe material40. For this reason, man-hours for manufacturing the plurality of components can be reduced.

The molding device1according to the present embodiment is the molding device1that performs expansion molding by supplying a fluid to the metal pipe material40(metal material) and molds a plurality of components in one time of molding with respect to one metal pipe material40.

The molding device1is the molding device1that performs expansion molding by supplying a fluid to the metal pipe material40. The molding device1molds a plurality of components in one time of molding with respect to one metal pipe material40. For this reason, the molding device1can mold the plurality of components at once only by performing one time of molding with respect to the one metal pipe material40. For this reason, man-hours for manufacturing the plurality of components can be reduced.

The molding device1may mold a component having a closed section as a component. In this case, the number of components can be reduced compared to a case of forming a structure in which a plurality of components are combined.

The molding device1may mold the long first component50and the second component51and the third component52, which are on both sides of the first component50in the longitudinal direction, as a plurality of components. Accordingly, as the long first component50is molded, the second component51and the third component52can be added to both sides thereof in the longitudinal direction and be molded.

The molding device1may have differential strength between one component and another component of a plurality of components. Accordingly, strength is easily adjusted according to use of each component.

An effect in a case of creating the front bumper100using the molding device1of the present embodiment will be described. Such a front bumper100is simply called an “example” in some cases. A case of creating a front bumper200shown inFIG.10will be described as a comparative example. As shown inFIG.10, in the front bumper200according to the comparative example, a bumper beam180is configured by two components180aand180b, a crush tube181is configured by two members181aand181b, and a crush tube182is configured by two members182aand182b. A plate-shaped metal material is molded into each of the components through pressing, roll forming, or the like. However, since the plate thickness and material strength of each component are different, manufacturing equipment such as a die is required according thereto, and it takes man-hours and costs. In addition, although respective components are assembled to be completed as the front bumper200through welding, bolt fastening, or the like, since the number of components is eight including the base plates83and84, man-hours and labor are required.

On the contrary, the molding device1of the present embodiment manufactures configuring components of the front bumper100according to the example in a steel tube air forming (STAF) process. Each of the bumper beam80and the crush tubes81and82is configured by one component. For this reason, the front bumper100can be kept to five components instead of eight components in the comparative example, and the number of components can be significantly reduced. In addition, in the front bumper200according to the comparative example, it is required to perform spot welding at dozens of places by bonding the components180aand180bthat have been trimmed and drilled after being molded through pressing or roll forming. On the contrary, in the front bumper100according to the example, the process is completed only by trimming and drilling after molding the bumper beam80. Accordingly, performance man-hours can be significantly reduced. The same applies to the crush tubes81and82.

Further, as shown inFIG.5, in the front bumper100according to the example, the bumper beam80and the crush tubes81and82are set as one molding product41, and the components can be manufactured in one time of molding. For this reason, the molding device1can significantly reduce man-hours and labor compared to the comparative example.

The front bumper100according to the example was evaluated through a strength test. The front bumper100according to the example and the front bumper200according to the comparative example were subjected to static press evaluation through analysis using a test device170shown by an imaginary line ofFIG.7. The crush tubes81and82on both sides were completely fixed, a load was applied to a front surface of the bumper beam80by the test device170, and evaluation was made for proof stress and an energy absorption amount (EA). The results are shown inFIG.11. Proof stress is substantially the same in the example and the comparative example until a stroke of 120 mm, and proof stress is higher in the example when exceeding the stroke of 120 mm. It can be seen that an EA amount is higher in the example over the entire stroke, and it can be seen that the performance of the front bumper is equal to or higher than in the comparative example. In the example, the number of components can be reduced by three components compared to the comparative example, and weight saving of 10% is possible while ensuring the same performance as in the comparative example.

The present disclosure is not limited to the embodiment described above. For example, the entire configuration of the molding device is not limited to that shown inFIG.1and can be appropriately changed without departing from the concept of the invention.

An aspect of a combination of a plurality of components is not limited. For example, the molding device may mold two components including a first component and a second component from one metal material. In addition, the molding device may mold four or more components from one metal material.

Although an example in which the front bumper is manufactured using a component molded by the molding device1has been described, a component of a rear bumper may be molded.

In addition, a component molded by the molding device1is not limited to a configuring component of the front bumper, the rear bumper, or the like, and other components may be molded. For example, as shown inFIG.12, left and right A pillars may be molded simultaneously. As shown inFIG.13, a long door impact beam and a short door impact beam may be molded simultaneously. The longer door impact beam is attached to a passenger seat. The shorter door impact beam is attached to a rear seat door.

The molding device may be a molding device that heats a metal material and that performs quenching, or a molding device using a hot stamping method may be adopted.

In addition, the molding device may be a molding device that performs expansion molding by supplying a fluid to a metal material, or a molding device using a hydroforming method may be adopted.