Patent Grant
8887544
This application is based upon and claims the benefit of the priority of Japanese patent application No. 2007-322508 filed on Dec. 13, 2007, the disclosure of which is incorporated herein in its entirety by reference thereto.
The present invention relates to a conveyor apparatus and hot press-forming apparatus comprising the same, and more particularly to a conveyor apparatus for die quenching and a hot press-forming apparatus comprising the same.
One method of mass producing automobile parts that require high strength employs a hot press-forming method or die quenching method. The die quenching method is a method in which a steel plate is heated to approximately 900° C., after which the steel plate is rapidly cooled at the same time that press-forming is performed and the formed product is quenched. Moreover, in order to heat the steel plate, conventionally a continuous heating furnace that is provided separately from the press-forming apparatus is typically used.
A hot press-forming system disclosed in Patent Document 1 employs a radiation heater that has this kind of heating furnace, where this radiation heater is provided separately from the hot press-forming apparatus in the stage before the hot press-forming apparatus. In addition, in patent document 1, a “walking beam, pusher and slider, belt conveyor, chain conveyor, and press transfer arm” are disclosed.
In Patent Document 2, a conveyor apparatus is disclosed that supports a metal material from the underneath side and conveys that material to the hot press mechanism by placing the middle section of the metal sheet that has been heated by the heating furnace on forks, and driving the forks along the conveyance direction.
[Patent Document 1] Japanese Patent Kokai Publication No. JP-P2006-289425A
[Patent Document 2] Japanese Patent Kokai Publication No. JP-P2007-175722A
The entire disclosures of the above Patent Documents 1 and 2 are incorporated herein by reference thereto. The analysis set forth below is given by the present invention.
The heated work is soft, so while conveying the heated work, there is a possibility that warping or bending of the work may occur. When the work is conveyed to the hot press-forming process in a warped state, the warped section of the work may interfere with the jigs and dies. In patent document 1 nothing is disclosed related to this problem that occurs when conveying the heated work.
With the conveyor apparatus disclosed in patent document 2, when conveying the metal material, the material is only supported from the underneath side, so there is a problem in that it is easy for the position of the metal material to shift, so that positioning in the hot press mechanism takes time, as well as it is difficult to increase the conveying speed.
It is an object of the present invention to provide a conveyor apparatus and a hot press-forming apparatus comprising the same, that when conveying heated work through direct conduction of electric current (termed as “conduction heated” or “conduction heating” hereinafter) to a downstream process, is able to prevent or suppress thermal deformation of the work, and make it easy to perform positioning of the work in a downstream process. In further aspects, it is an object to provide a conveying method and a hot press-forming method.
According to a first aspect of the present invention, there is provided a conveyor apparatus that conveys a work that has been conduction heated at an energizing position (i.e., conduction-heating position) to a processing position that is separated in the horizontal direction from the energizing position in order to perform hot press-forming, and comprises: a holding member(s) that freely clamps both end sections in the lengthwise direction of the work that has been conduction heated; a drive mechanism that moves the holding member from at least the energizing position to the processing position; and a guide member that extends between the energizing position and processing position and is capable of guiding and supporting a middle section in a lengthwise direction of the work that has been conduction heated and is under conveyance toward the processing position. According to a second aspect of the present invention, there is provided a hot press-forming apparatus that comprises the conveyor apparatus. According to a third aspect of the present invention, there is provided a conveying method for conveying work that has been conduction heated at an energizing position to a processing position that is separated in a horizontal direction from the energizing position in order to perform hot press-forming; wherein the method comprises: freely clamping, by a holding member(s), both end sections in the lengthwise direction of the work that has been conduction heated; moving the holding member(s) from at least the energizing position to the processing position, using a drive mechanism; and guiding and supporting a middle section in a lengthwise direction of the work that has been conduction heated and is under conveyance toward the processing position, by using a guide member(s).
According to a fourth aspect of the present invention, there is provided a hot press-forming method that uses the conveying method of the third aspect.
According to a fifth aspect of the present invention, there is provided a method of producing a hot press-forming product using the hot press-forming method.
When performing hot press-forming, and particularly when holding both ends of heated work in order to perform die quenching, the middle section of the work droops, and when the holding force is very large, the work elongates in the lengthwise direction. With the present invention, by holding both ends of the work by a holding member when conveying conduction heated work, positioning the work at a downstream process, or in other words, positioning the work at the hot press-forming process is simplified, and by supporting and guiding the middle section of work by a guide member, it is possible to prevent or suppress thermal deformation of the work such as drooping of the middle section of the work or elongation of the work due to holding. As a result, when conveying conduction heated work from the energizing position to the processing position, interference between the work and the parts of the conveyor apparatus is prevented, and it is possible to convey the work to the processing position in a positioned state, and thus positioning at the processing position becomes easy, and hot press-forming can be executed quickly. Moreover, by conveying the work in a supported state, shifting of the position of the work is prevented, so it is also possible to increase the speed of conveying the work from the energizing position to the processing position.
In preferred modes of the present invention, at least the processing position is located at the same height as the energizing position, the guide member extends between the energizing position and the processing position and is inclined so that the processing position side thereof is higher than the energizing position side. Furthermore, it is preferred that the work or blank feeding position, the energizing position, the processing position and the work or formed product discharge position be at the same height. In these modes, conveying is made simple and efficient, and transfer type conveyance can be easily applied to the conveyor apparatus of the present invention.
In a preferred mode of the present invention, the guide member is a rail on which an undersurface of the work is slidable. It is further preferred that a plurality of guide members be arranged with respect to the lengthwise direction of the work. In this mode, warping or deflection of the work can be prevented or suppressed even when the work is an elongated sheet material and the spacing between the support positions is large.
In a preferred mode of the present invention, the holding members at least freely support the work at the energizing position and processing position, as well as freely move back-and-forth between both the positions. In this mode, by moving the holding members back-and-forth, the conveyor apparatus can be simply constructed.
In a preferred mode of the present invention, a plurality of holding members are provided, and together with freely holding the work at the work feeding position and at the discharge position where the hot press-formed work is discharged, freely move back-and-forth between the feeding position and energizing position, between the energizing position and the processing position, and between the processing position and the discharge position. In this mode, the whole conveyor apparatus can be simply constructed and work is conveyed efficiently. In addition, synchronizing the conveyance of a plurality of works, or in other words, blanks and formed products can be performed easily, and thus the time required to perform a series of cycles, which include feeding (setting) a blank, heating, hot pressing and discharging the formed product, can be reduced.
The conveyor apparatus of a preferred mode of the present invention is located along the conveyance direction of the blank and has a pair of parallel arms to which a pair of the holding members are mounted, and the drive mechanism comprises: a conveyance direction drive mechanism that drives the pair of parallel arms such that they freely move along the conveyance direction; a raising (lifting) and lowering mechanism that drives the pair of parallel arms such that they freely move back-and-forth along the up and down (vertical) direction; and a width direction drive mechanism that drives the pair of parallel arms such that they freely move back-and-forth in the width direction perpendicular to the conveyance direction and up and down direction so that the holding members can freely hold the work. In this mode, the conveyor apparatus is compact and work is conveyed efficiently.
In a preferred mode of the present invention, as illustrated in
In a preferred mode of the present invention, the hot press-forming apparatus comprises a cooling die that together with performing hot pressing of the work, also performs rapid cooling and quenching. In this mode, the energizing position and the processing position are arranged such that they are separated, so that with the die of the hot press mechanism or cooling die, sufficient rapid cooling is possible at the same time as hot pressing, and it is possible to adequately quench the formed product. Preferably the hot press-forming apparatus comprises a forced cooling die, or depending on the circumstances, a cooling die that maintains a temperature at which it is possible to execute die quenching by natural cooling. The hot press-forming apparatus may also comprise a path that is formed in the die and through which a fluid such as water, oil or air circulates, and a pump for circulating the fluid in the path.
The conveyor apparatus of a preferred mode of the present invention performs a process of conveying heated work from the energizing position to the processing position, while at the same time performs a process of conveying formed products from the processing position to the discharge position where work is discharged, and further performs a process of feeding new work to the energizing position. In this mode, it is possible to simultaneously execute a supply process of supplying work or blanks to the equipment, a conveyance process of conveying heated work inside the equipment and a discharge process of discharging work or formed products from the equipment, so the conveyor apparatus and conveyance process can be simplified.
In a preferred mode of the present invention, the hot pressing is die quenching that performs rapid cooling and quenching during hot pressing.
In a preferred mode of the present invention, a heated blank is quickly conveyed from the energizing position to the processing position within 10 seconds, and preferably within 5 seconds or less, in order to prevent or suppress the blank temperature from dropping or the blank from oxidizing.
In a preferred mode of the invention, conduction heating is sufficient as long the work can be heated to a temperature at which hot press-forming is possible. For example, when the work is steel, between the critical point A1 and the liquid-phase precipitation point, conduction heating should be between 850 and 1200° C. In addition, by setting the temperature of the die of the hot press mechanism to between room temperature and approximately 250° C., it is possible, for example, to cool a blank that has been heated to the A1 point or above at a rate of 20° C./s or more until the temperature reaches approximately 220° C. or less and sufficient quench hardening is obtained.
The present invention can be applied to conveying various kinds of materials and various metal work such as steel or aluminum that are capable of conduction heating, thermal processing and particularly die quenching.
Examples of the present invention will be explained below with reference to the accompanying drawings.
As illustrated in
By employing conduction heating and transfer conveyance, the hot press-forming apparatus 1 of an example of the present invention only requires half or less the installation area compared to a hot press-forming system that uses a continuous heating furnace. Moreover, with the hot press-forming apparatus 1 of this example, the conduction heating time and the time to convey work from the energizing position to the processing position are both only a few seconds, with the total time required from the start of conduction heating to the completion of formation being only a few seconds to a few tens of seconds. On the other hand, with a hot press-forming system that uses a continuous heater, a few minutes are required to perform radiation heating in the furnace, so the total time required from the start of heating to the completion of forming is about 2 to 3 minutes.
The feeding mechanism 2 is a robot mechanism that, according to an instruction from the control mechanism 6, takes work or a blank one at a time from a magazine in which a plurality of works or blanks are stored, and supplies the work one at a time to the feeding position of the conduction heating mechanism 3 or hot press-forming apparatus 1.
The conduction heating mechanism 3, according to an instruction from the control mechanism 6, clamps or unclamps the work fed, as well as energizes and heats the work that is clamped and for which conveying has stopped.
The hot press mechanism 4, according to an instruction from the control mechanism 6, performs hot pressing and rapid cooling of the heated work, and basically forms the formed product from the work by performing hot pressing one time.
The conveyor apparatus 5, according to an instruction from the control mechanism (unit) 6, freely clamps both end sections in the lengthwise direction of the conduction heated work, and can hold or release hold of the work at the feeding position where the work or blank is fed into the hot press-forming apparatus 1 or conduction heating mechanism 3, at the energizing position where the conduction heating mechanism 3 energizes the work, at the processing position where the hot press mechanism 4 hot presses the work, and at the discharge position where the work or formed product is discharged from the hot press-forming apparatus 1. In addition, the conveyor apparatus 5 moves back-and-forth between the feeding position and the energizing position, between the energizing position and the processing position, and between the processing position and discharge position.
The control mechanism 6 comprises: various sensors that are provided in the mechanisms and apparatus 2 to 5, for example a stroke sensor that monitors the stroke of the die of the hot press mechanism 4 and a microswitch that detects status of the feeding unit 1 and the conveyor apparatus 5 and drive units thereof, for example an air cylinder; and a microcomputer that receives information that is outputted from sensors, such as a temperature sensor that detects the temperature of a blank that was heated by the conduction heating mechanism 3, and sends control signals based on that information in order to synchronously operate the mechanisms and apparatus 2 to 5.
As is illustrated in
The conduction heating mechanism 3 has a plurality of electrodes 31 that clamp and energize a blank at the energizing position P1, an electrode raising and lowering cylinder 32 that raises or lowers the plurality of electrodes 31 and clamps or unclamps work, a movable clamp cylinder 33 that freely drives and moves a pair of vertically opposed electrodes 31 in a specified direction or along the lengthwise direction of the work, a straight movement guide 34 that guides the pair of moving electrodes 31, and support rods 35 that are located directly underneath the energizing position P1 and freely support the middle section of a blank by preventing as much as possible any drooping of the middle section of a blank caused by conduction heating. Preferably, of the pairs of upper and lower electrodes (31, 31), (31, 31) that face each other on the left and right, the clamped position by the pair of upper and lower electrodes (31, 31) on one side is fixed, and the pair of upper and lower electrodes (31, 31) on the other side move along in the lengthwise direction of the blank. During conduction heating, the pair of upper and lower electrodes (31, 31) on the one side hold one side of the blank at the fixed position, and the pair of upper and lower electrodes (31, 31) on the other side hold the other side of the blank, while at the same time apply adequate tension to the work by moving along the lengthwise direction of the blank according to the thermal deformation of the blank in order to prevent as much as possible any deformation of the work.
The hot press mechanism 4 comprises a cooling die 41 that performs hot pressing and rapid cooling (quenching) of the conduction heated work at the processing position P2.
The conveyor apparatus 5 comprises: a pair of parallel arms 51 that extend along the conveyance direction of the work; a plurality of pairs of clamps 53a to 53c (see (A) of
The guide member 54 is a rail on which the underneath surface of the work can slide, and is formed from pipe. Particularly, as is illustrated in
The plurality of pairs of clamps 53a to 53c are arranged with uniform pitch on a pair of parallel arms 51 to correspond to the interval between the feeding position P0, energizing position P1, processing position P2 and discharge position P3. It is possible to use various kinds of pairs of holding fixtures such as tabs that hold the work, fixtures that are driven by air cylinders, chucks, suction plates and the like as the plurality of pairs of clamps 53a to 53c. As the driving method, it is possible to use servomotors instead of cylinders 52a to 52c.
The basic conveyance process by the conveyor apparatus of an example of the present invention, and the heating and forming process by the hot press-forming apparatus of the example described above will be explained.
As illustrated in
When the cycle explained above is continuously repeated, the process of conveying the work or blank from the feeding position P0 to the energizing position P1 in step S3, the process of conveying the completely conduction heated work from the energizing position P1 to the processing position P2 in step S10, and the process of conveying the work or formed product from the processing position P2 to the discharge position P3 in step 13 are synchronized and executed simultaneously.
In step S10, when the conduction heated work is conveyed to the hot press process, the guide members 54 of the conveyor apparatus 5 of the present invention function.
The conveyance, heating and formation processes by the hot press-forming apparatus of the example of the present invention described above will be explained in detail. (A) to (H) of
As illustrated in (A) and (A′) of
As illustrated in (A) and (B) of
As illustrated in (B) and (C) of
As illustrated in (C) and (D) of
As illustrated in (D) and (E) of
As illustrated in (E) and (F) of
As illustrated in (F) and (G) of
Referring to
Industrial Applicability
The conveyor apparatus and hot press-forming apparatus comprising the same of the present invention is applied to the formation or manufacture, and particularly die quenching of sheet metal material, and more specifically is applied to the formation or manufacture of automobile parts for which mass production is required, for example is preferably applied to the formation or manufacture of various reinforced members, particularly door beams and bumper reinforcement of an automobile body.
The modes or examples of the invention can be modified or adjusted within the framework of the entire disclosures (including the claims) of the present invention, and a based on the technical scope of the invention. Moreover, various combinations or selections of the various disclosed elements are possible within the scope of the claims of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-322508 | Dec 2007 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2008/067476 | 9/26/2008 | WO | 00 | 6/14/2010 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2009/075135 | 6/18/2009 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5060500 | Ohneda et al. | Oct 1991 | A |
| 6347540 | De Biasi | Feb 2002 | B1 |
| 7285761 | Terziakin | Oct 2007 | B1 |
| Number | Date | Country |
|---|---|---|
| 19506071 | Aug 1996 | DE |
| 4-17400 | Feb 1992 | JP |
| 2002-248525 | Sep 2002 | JP |
| 2005-342742 | Dec 2005 | JP |
| 2006-289425 | Oct 2006 | JP |
| 2007-136533 | Jun 2007 | JP |
| 2007-175722 | Jul 2007 | JP |
| 2007175722 | Jul 2007 | JP |
| Entry |
|---|
| English translations of Japanese patent application JP 2007-136533, “Forming method using transfer press and transferpress device”, by I. Yuichi and S. Tetsuo, Jun. 7, 2007. |
| English translations of Japanese patent application JP 2002-248525, “Method for hot pressing metal plate and apparatus therefor”, by H. Koichi, N. Masahito, K. Yoshiyuki, Sep. 3, 2002. |
| English translations of Japanese patent application JP H10-315000, “Press”, by K. Kazunori and M. Saburou, Feb. 12, 1998. |
| English translations of Japanese patent application JP 2005-342742, “Method and apparatus for pressing galvanized steel sheet and pressed goods made of galvanized steel sheet”, by M. Yutaka, Dec. 15, 2005. |
| International Search Report issued by the Japanese Patent Office as the International Searching Authority on Dec. 12, 2008 in International Application No. PCT/JP2008/067476. |
| English Translation of the International Preliminary Report on Patentability (IPRP) (Forms PCT/IB/338 and PCT/IB/373) and Written Opinion of the International Searching Authority and International Preliminary Report on Patentability (Form PCT/ISA/237) issued in corresponding International Application No. PCT/JP2008/070120 dated Aug. 10, 2010. |
| Official Action dated Jan. 5, 2011, issued by the Japanese Patent Office in corresponding Japanese Patent Application No. 2007-322508, and English translation of Official Action. |
| Extended European Search Report dated Jul. 24, 2013 issued in corresponding European Patent Application No. 08 859 427.0. |
| Number | Date | Country | |
|---|---|---|---|
| 20100288008 A1 | Nov 2010 | US |
