Workpiece transportation member, workpiece transportation device, and heat treatment device

This workpiece transportation member includes at least one pair of support beams that each have a configuration where a placing portion configured to allow a heated workpiece to be placed is provided at an upper end portion, extend in a predetermined length direction, and are disposed at an interval in a width direction orthogonal to the length direction and a connecting portion configured to connect the at least one pair of support beams to each other at a position below the position of the upper end portion.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a workpiece transportation member, a workpiece transportation device, and a heat treatment device, and particularly to a workpiece transportation member, a workpiece transportation device, and a heat treatment device that are suitable for the transportation and heat treatment of steel sheets for hot pressing.

The present application claims priority based on Japanese Patent Application No. 2018-114113 filed in Japan on Jun. 15, 2018, the contents of which are incorporated herein by reference.

RELATED ART

High strength steel sheets are widely used as the components of automobile bodies in order to achieve both additional improvement in the strength, stiffness, and collision safety of automobile bodies and improvement in gas mileage by the weight reduction of automobile bodies. However, the press formability of steel sheets degrades with the high-strengthening of steel sheets. Therefore, there is a case where it is not possible to manufacture high-strength press-formed articles having a desired shape.

Recently, hot pressing methods (also referred to as hot stamping methods) have been used as methods for press-forming the components of automobile bodies. In the hot pressing methods, steel sheets for hot pressing (blanks) that are subjected to press forming are press-formed and quenched by rapid cooling immediately after being heated to a temperature that is equal to or higher than the Ac3point with a heating apparatus. This treatment is also referred to as die quenching. With this treatment, high-strength press-formed articles having a desired shape are manufactured.

In order to load and unload steel sheets for hot pressing or the like as workpieces into and from heating furnaces, there is a case where loading and unloading devices are used (for example, refer to Patent Document 1). A loading and unloading device described in Patent Document 1 has a robot arm and a fork-shaped hand attached to the tip end of the robot arm.

The hand is configured to have a plurality of elongated rod-shaped forks arranged in parallel. Each fork typically has a quadrangular cross-sectional shape that is orthogonal to the length direction of the fork. In addition, a planar shaped workpiece is placed on each fork.

PRIOR ART DOCUMENT

Patent Document

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

When a hot workpiece is placed on the upper surface of the fork, the fork receives radiation heat from the workpiece. The radiation heat mainly transmits in the upper portion of the fork. Therefore, the temperature of the upper portion of the fork significantly rises. On the other hand, the temperature of the lower portion of the fork does not significantly rise. As a result, in the fork, the amount of thermal expansion of the upper portion becomes larger than the amount of thermal expansion of the lower portion. Then, the fork, particularly the tip end of the fork, warps downward.

As the warpage amount of the fork increases, the total height of the fork and the workpiece placed on the fork increases. When the total height increases, the fork and the workpiece come into contact with the inlet and outlet of a heating furnace during the transportation of the workpiece. As a result, there is a concern that a trouble of the heat treatment furnace or the fork being broken and a trouble of the workpiece being damaged may be caused.

In order to prevent the above-described warpage of the fork, Patent Document 1 discloses a configuration where a cover member having a high radiation heat reflectance is overlaid on the upper surface of the fork. This configuration is intended to make the amount of thermal expansion more even between the upper portion and the lower portion of the fork. In addition, in order to prevent the warpage of the fork, conceivable is a configuration where the fork is formed of a material that is divided into upper and lower portions and the coefficient of thermal expansion of the upper member is made smaller than the coefficient of thermal expansion of the lower member.

However, in the above-described configuration where the cover member is used, a material that configures the cover member becomes necessary in addition to a material that configures the fork, which increases the manufacturing cost of the hand. In addition, in the configuration where the coefficient of thermal expansion is changed between the upper portion and the lower portion of the fork, two different kinds of materials are used, and there is a need for a special process of the combination of these materials, which increases the manufacturing cost of the fork.

In addition, when the heating pattern of workpieces and the heating temperature of workpieces (hereinafter, also referred to as the heating pattern of workpieces and the like) vary, the warpage amount of the fork that receives heat from workpieces also varies. Therefore, in a case where the cover member is used, there is a need for changing the thickness of the cover member in the fork according to the heating pattern of workpieces and the like. As a result, it becomes necessary to prepare a large number of kinds of hands according to the heating pattern of workpieces and the like. In addition, in a case where the coefficient of thermal expansion is changed between the upper portion and the lower portion of the fork, there is a need for selecting a material having a coefficient of thermal expansion in accordance with the heating pattern of workpieces and the like. As a result, it becomes necessary to prepare a large number of kinds of hands.

In consideration of the above-described circumstances, an object of the present invention is to provide a workpiece transportation member, a workpiece transportation device, and a heat treatment device that are capable of suppressing the occurrence of warpage attributed to heat that comes from workpieces and require a low cost relating to the transportation of workpieces.

Another object of the present invention is to provide a workpiece transportation member, a workpiece transportation device, and a heat treatment device that are capable of further improving the operating rate of the heat treatment device configured for the heat treatment of workpieces.

Means for Solving the Problem

(1) In order to solve the above-described problem, a workpiece transportation member according to an aspect of this invention includes at least one pair of support beams that each have a configuration where a placing portion configured to allow a heated workpiece to be placed is provided at an upper end portion, extend in a predetermined length direction, and are disposed at an interval in a width direction orthogonal to the length direction and a connecting portion configured to connect the at least one pair of support beams to each other at a position below a position of the upper end portion.

For example, in a configuration where a first connecting portion configured to connect the upper portions of a plurality of support beams and a second connecting portion configured to connect the lower portions of the plurality of support beams are provided, the elongation amount of the first connecting portion and the elongation amount of the second connecting portion, which are attributed to radiation heat from workpieces, are different from each other. As a result, the support beam warps such that the elongation amount of the upper end portion of the support beam, which is attributed to radiation heat, becomes larger than the elongation amount of the lower end portion of the support beam. On the other hand, according to the configuration (1) described above, it is possible to connect the support beams with one connecting portion. With such a configuration, it is possible to more reliably suppress the occurrence in the support beam of the warpage of the workpiece transportation member, particularly, warpage causing the elongation amount of the upper end portion of the support beam, which is attributed to radiation heat from the workpiece, to be larger than the elongation amount of the lower end portion of the support beam. Moreover, it is possible to form the workpiece transportation member with a single material, and thus it is possible to further reduce the manufacturing cost of the workpiece transportation member. In addition, it is possible to suppress the warpage of the workpiece transportation member regardless of the heating pattern of the workpiece and the heating temperature of the workpiece. Therefore, it is not necessary to replace the workpiece transportation member according to workpieces having a different heating pattern of the workpiece and the like, and the same workpiece transportation member can be used. Therefore, since it is possible to decrease the replacement frequency of the workpiece transportation member in the step of heat-treating workpieces, a low cost relating to the transportation of workpieces is required, and it is possible to further improve the operating rate of the heat treatment device in which the workpiece transportation member is used.

(2) There is a case where the connecting portion connects the at least one pair of support beams to each other at one place in a height direction orthogonal to both the length direction and the width direction.

According to this configuration, it is possible to more reliably suppress the occurrence in the support beam of the warpage of the workpiece transportation member, particularly, warpage causing the elongation amount of the upper end portion of the support beam to be larger than the elongation amount of the lower end portion of the support beam.

(3) There is a case where two support beams are provided at an interval in the width direction, and each support beam is formed in a flat plate shape having the width direction as the thickness direction.

According to this configuration, it is possible to stably support workpieces with the two support beams while the amount of heat transmitting from the workpieces to the workpiece transportation member is further reduced by further decreasing the contact area between the workpieces and each support beam.

(4) There is a case where the connecting portion is disposed in a middle portion of the support beam in the height direction, whereby the workpiece transportation member is formed in an H shape when viewed in the length direction.

According to this configuration, it is possible to realize the workpiece transportation member having extremely high bending rigidity against the load of workpieces. In addition, since it is possible to decrease the projected area of the connecting portion when viewed from the upper end side of the support beam, it is possible to decrease the influence of radiation heat from workpieces. As a result, it is possible to more reliably suppress the warpage of the support beam attributed to the radiation heat. Furthermore, it is possible to make the temperature distribution of the support beam in the thickness direction of the support beam, which is attributed to the conduction of heat from workpieces more even. Therefore, it is possible to more reliably suppress the occurrence of a temperature difference in the support beam that causes large warpage.

(5) There is a case where the connecting portion is disposed in a lower end portion of the support beam in the height direction, whereby the workpiece transportation member is formed in a U shape when viewed in the length direction.

According to this configuration, it is possible to realize the workpiece transportation member having sufficiently enhanced bending rigidity against the load of workpieces.

(6) There is a case where the connecting portion is formed in a plate shape extending in the length direction.

According to this configuration, the connecting portion continuously extends in the length direction, whereby it is possible to further enhance the coupling stiffness between the connecting portion and the support beam. As a result, the workpiece transportation member is capable of further decreasing the deflection amount (subduction amount) of the workpiece transportation member on the tip end side when a workpiece is placed on the workpiece transportation member.

(7) There is a case where a plurality of the connecting portions are provided at an interval in the length direction.

According to this configuration, the plurality of connecting portions support the support beams in cooperation with each other, whereby it is possible to further enhance the coupling stiffness between the connecting portion and the support beam. As a result, the workpiece transportation member is capable of further decreasing the deflection amount of the workpiece transportation member on the tip end side when a workpiece is placed on the workpiece transportation member. Furthermore, the connecting portions are capable of reducing the amount of radiation heat received from the workpiece. As a result, it is possible to more reliably suppress the warpage of the support beam attributed to the radiation heat.

(8) In order to solve the above-described problem, a workpiece transportation device according to an aspect of this invention includes a workpiece transportation fork formed in a fork shape as a whole by having a configuration where a plurality of the workpiece transportation members are arranged in the width direction.

According to this configuration, the workpiece transportation fork is formed of the workpiece transportation members in which warpage attributed to heat from the workpiece is suppressed. Therefore, when a workpiece is placed on the workpiece transportation device, it is possible to more reliably suppress the occurrence of the warpage of the workpiece transportation member. In addition, since it is possible to suppress the warpage of the workpiece transportation member regardless of the heating pattern of the workpiece and the like, it is not necessary to replace the workpiece transportation fork according to workpieces having a different heating pattern of the workpiece and the like, and the same workpiece transportation fork can be used. Therefore, it is possible to decrease the replacement frequency of the workpiece transportation fork in the step of heat-treating the workpiece, and thus it is possible to further improve the operating rate of the heat treatment device in which the workpiece transportation member is used.

(9) In order to solve the above-described problem, a heat treatment device according to an aspect of the present invention includes the workpiece transportation device and a heating furnace configured to heat a workpiece that is transported by the workpiece transportation device.

According to this configuration, it is possible to more reliably suppress the occurrence of warpage in the workpiece transportation member. In addition, since it is possible to suppress the warpage of the workpiece transportation member regardless of the heating pattern of the workpiece and the like, it is not necessary to replace the workpiece transportation fork according to workpieces having a different heating pattern of the workpiece and the like, and the same workpiece transportation fork can be used. Therefore, it is possible to decrease the replacement frequency of the workpiece transportation fork in the heat treatment device, and thus it is possible to further increase the efficiency of the operation for loading and unloading workpieces into and from the heat treatment furnace and to further improve the operating rate of the heat treatment device.

Effects of the Invention

According to the present invention, it is possible to realize a workpiece transportation member that is capable of suppressing the occurrence of warpage attributed to heat that comes from workpieces and requires a low cost relating to the transportation of workpieces.

EMBODIMENTS OF THE INVENTION

Hereinafter, an embodiment for carrying out the present invention will be described with reference to drawings.

FIG.1is a schematic partial cross-sectional side view of a heat treatment device1according to an embodiment of the present invention and shows only a part of the heat treatment device1.FIG.2is a schematic view showing the configuration of a main part of a heat treatment furnace2in the heat treatment device1and shows a cross section orthogonal to a transportation direction A1of a workpiece100.

With reference toFIG.1andFIG.2, the heat treatment device1is a device configured to heat steel sheets for hot pressing as the workpiece100for hot pressing processes. The workpiece100is heated in the heat treatment device1in a state of being formed in, for example, a rectangular flat plate shape. The heat treatment device1heats the workpiece100to, for example, the Ac3point or higher and 950° ° C. or lower. The workpiece100is heated in the heat treatment device1and then formed into a predetermined member by a hot pressing process. Examples of the predetermined member include pillars, members, and the like in the monocoque structures of automobiles.

The heat treatment device1has the heat treatment furnace2and a workpiece transportation device3.

The heat treatment furnace2is a furnace configured to heat the workpiece100that is transported by the workpiece transportation device3to, for example, the Ac3point or higher and 950° C. or lower. The heat treatment furnace2is a far-infrared type multistage heating furnace and is capable of collectively accommodating N (N is a natural number of one or larger, for example, N=7) workpieces100.

The heat treatment furnace2has a housing4, N heater units5installed in the housing4, N inlet shutters6and N outlet shutters7configured to open and close the housing4.

The housing4is formed in, for example, a substantially square prism shape that is hollow. In addition, in the housing4, the upstream-side side wall in the transportation direction A1(the horizontal direction inFIG.1) of the workpiece100in the heat treatment device1is an inlet-side side wall4a. In addition, the downstream-side side wall in the transportation direction A1is an outlet-side side wall4b. Opening parts4cand4dfor passing the workpiece100are formed in the inlet-side side wall4aand the outlet-side side wall4b.

N opening parts4care formed vertically on the inlet side at substantially equal pitches. Similarly, N opening parts4don the outlet side are formed vertically at substantially equal pitches. The opening part4cpreferably has a minimum necessary height that is large enough for a workpiece transportation fork22, which will be described below, of the workpiece transportation device3and the workpiece100placed on the workpiece transportation fork22to be inserted. The opening part4dpreferably has a minimum necessary height that is large enough for a workpiece transportation fork32, which will be described below, of the workpiece transportation device3and the workpiece100placed on the workpiece transportation fork32to be inserted. As the height of each opening part4cand the height dimension of each opening part4ddecrease, it is possible to further shorten the intervals between the heater units5. Therefore, it is possible to further increase the heat efficiency of the heat treatment furnace2.

The inlet shutters6are disposed on the plurality of opening parts4c, respectively, and the outlet shutters7are disposed on the plurality of opening parts4d, respectively. The inlet shutters6and the outlet shutters7are opened and closed with an opening and closing mechanism, not shown, thereby opening and closing the corresponding opening parts4cand4d.

The heater unit5is disposed between the opening part4cand the opening part4darranged in the transportation direction A1. That is, N heater units5are disposed between N opening parts4cand N opening parts4dthat are arranged in the transportation direction A1and form pairs, respectively. The heater units5that are adjacent to each other vertically are not separated with a partition wall or the like. Therefore, the heater units5that are adjacent to each other vertically face each other directly.

Each heater unit5has a far-infrared heater11, a heater support material12, and a workpiece support material13.

The far-infrared heater11is a horizontally-disposed planar heater. The far-infrared heater11has a sintered body of far-infrared radiation ceramics, for example, Al2O3, SiO2, ZrO2, TiO2, SiC, CoO, Si3N4, or the like and a heating wire provided in the sintered body. When an electric current is made to flow through this heating wire, far-infrared energy is radiated from the far-infrared heater11. The far-infrared heater11is supported by a plurality of the heater support materials12.

Each heater support material12is supported by the housing4. The far-infrared heater11is placed on each heater support material12. The workpiece support material13is disposed below the far-infrared heater11and the heater support material12.

The workpiece support materials13are arranged at substantially equal pitches in the horizontal direction LR when viewed along the transportation direction A1. Each workpiece support material13is, for example, a block-shaped member extending along the transportation direction A1and is supported by the housing4. The workpiece100is placed on the plurality of workpiece support materials13. The plurality of workpiece support materials13collaboratively support the workpiece100such that the workpiece100comes to a horizontal posture.

With the above-described configuration, at the time of heating the workpiece100, first, the inlet shutter6that closes the opening part4c, into which the workpiece is loaded, is opened. Next, a workpiece loading device15, described below, in the workpiece transportation device3transports the workpiece100to the corresponding workpiece support material13through the opening part4cin an open state and places the workpiece100on the workpiece support material13. Next, the inlet shutter6is closed. After that, the workpiece100is heated with the heater unit5. When this heating operation is completed, the outlet shutter7that faces the workpiece100is opened, whereby the corresponding opening part4dis opened.

Next, a workpiece unloading device16, described below, in the workpiece transportation device3lifts the workpiece100from the workpiece support material13and unloads the workpiece100to the outside of the heat treatment furnace2through the opening part4din an open state. The workpiece100transported to the outside of the heat treatment furnace2is formed into a predetermined shape by a hot pressing process with a hot pressing apparatus, not shown.

Next, the configuration of the workpiece transportation device3will be described.

The workpiece transportation device3has the workpiece loading device15and the workpiece unloading device16.

FIG.3is a schematic plan view of the workpiece loading device15.FIG.4(A)is a cross-sectional view of a workpiece transportation member24in the workpiece loading device15and shows a state of the workpiece transportation member24viewed in a cross section orthogonal to the length direction X1.FIG.4(B)is a perspective view showing the workpiece transportation member24alone.

With reference toFIG.1toFIG.4, in the present embodiment, the workpiece loading device15is configured to load the workpiece100into one heater unit5at a time. The workpiece loading device15is installed on the upstream side of the heat treatment furnace2in the transportation direction A1. The workpiece transportation device3loads the workpiece100into the corresponding heater unit5through one of the plurality of opening parts4c.

The workpiece loading device15has a moving mechanism21and a workpiece transportation fork22.

The moving mechanism21is provided to move the workpiece transportation fork22. The moving mechanism21is, for example, an articulated robot arm. The moving mechanism21is configured to be capable of moving the workpiece transportation fork22horizontally, vertically, and rotationally. It should be noted that the moving mechanism21needs to be configured to be capable of loading the workpiece transportation fork22and the workpiece100placed on the workpiece transportation fork22into the heat treatment furnace2, and the specific configuration thereof is not limited to robots. An attachment23is provided at the tip end portion of the moving mechanism21, and the workpiece transportation fork22is fixed to the attachment23.

The workpiece transportation fork22is provided as a portion on which the workpiece100is placed. When the workpiece transportation fork22is moved with the moving mechanism21, the workpiece transportation fork22is capable of moving the workpiece100placed on the workpiece transportation fork22.

The workpiece transportation fork22has a plurality of (eight in the present embodiment) workpiece transportation members24and a linking body25connected to the workpiece transportation members24. The workpiece transportation fork22has a configuration where the plurality of workpiece transportation members24are arranged at predetermined pitch in the width direction Y1and is thereby formed into a fork shape as a whole.

It should be noted that, in the present embodiment, the longitudinal direction of the workpiece transportation member24will be referred to as the length direction X1. In addition, a direction that is orthogonal to the length direction X1and in which the plurality of workpiece transportation members24are arranged will be referred to as the width direction Y1. In addition, a direction that is orthogonal to both the length direction X1and the width direction Y1will be referred to as the height direction Z1. In addition, unless particularly otherwise described, description will be made based on a state where the workpiece transportation fork22is in a horizontal support posture. The “horizontal support posture” refers to the posture of the workpiece transportation fork22when the workpiece100is horizontally placed on the workpiece transportation fork22.

The linking body25is provided as a base portion of the workpiece transportation fork22. The linking body25has, for example, two linking rods25aextending along the width direction Y1. These two linking rods25aare fixed to the attachment23of the moving mechanism21. The two linking rods25aare disposed parallel to each other at an interval in the length direction X1. In the present embodiment, the substantial centers of the linking rods25ain the width direction Y1are connected to the attachment23. The linking body25fixes the base end section of each workpiece transportation member24.

The workpiece transportation member24is provided as a skewer-shaped portion of the workpiece transportation fork22. The workpiece transportation member24is a portion on which the workpiece100is directly placed, and the workpiece100is placed on the upper end portion of the workpiece transportation member24. The number of the workpiece transportation members24and the disposition pitches in the width direction Y1are appropriately set depending on the shape and dimension of the workpiece100. In the present embodiment, the individual workpiece transportation members24have the same configuration, which is capable of enhancing the versatility of the workpiece transportation member24, and thus it is possible to further reduce the manufacturing cost of the workpiece transportation fork22.

The workpiece transportation member24has at least one pair of support beams26and a connecting portion27configured to connect the plurality of support beams26to each other.

In the present embodiment, one pair of the support beams26are provided. That is, two support beams26are provided at an interval in the width direction Y1. The shapes, dimensions, and positions in the height direction Z1of the individual support beams26are set to be the same. In the present embodiment, the pair of support beams26are disposed parallel to each other. The support beam26is a member that extends in the length direction X1as the longitudinal direction.

In the present embodiment, the support beam26is formed in a rectangular flat plate shape and is disposed such that the width direction Y1becomes the thickness direction. With this configuration, the support beams26are vertically disposed.

As described above, the support beam26is formed in a shape that is thin in the width direction Y1and long in the height direction Z1, and both a right side surface26aand a left side surface26bof the support beam26in the width direction Y1are disposed in open spaces and are not disposed in closed spaces. The “closed space” refers to, for example, the inside space of a rectangular space in a case where the workpiece transportation member is rectangular in a cross section orthogonal to the length direction X1. Such a configuration makes it difficult for a temperature difference to be generated between an upper end portion26uand a lower end portion26dof the support beam26.

In the present embodiment, the upper end portion26uof the support beam26is a substantially horizontal flat surface. It should be noted that chamfered portions may be formed at corner portions of the upper end portion26u. In the present embodiment, the lower end portion26dof the support beam26is a substantially horizontal flat surface. It should be noted that chamfered portions may be formed at corner portions of the lower end portion26d.

On the upper end portion26uof the support beam26, placing portions28configured to allow the heated workpiece100to be placed are formed. The placing portion28may be a flat surface formed of the upper end portion26u. In a case where the placing portion28is a flat surface, one pair of the placing portions28and28on the pair of the support beams26and26are flush surfaces having aligned positions in the height direction Z1. In the present embodiment, the placing portion28is formed by providing a projection-shaped member on the upper end portion26u. The projection-shaped members may be discretely disposed in the length direction X1or may continuously extend in the length direction X1.

With the above-described configuration, the placing portions28on one support beam26and the placing portion28of the other support beam26are disposed apart from each other in the width direction Y1. In addition, the interval between the pair of placing portions28and28in the width direction Y1is the support span of the workpiece100in one workpiece transportation member24. The pair of placing portions28and28are apart from each other as described above, whereby radiation heat from a portion100aof the workpiece100positioned between the pair of placing portions28and28does not easily reach the connecting portion27.

The pair of support beams26and26are connected to each other with the connecting portion27at a position below the position of the upper end portion26u.

In the present embodiment, the connecting portion27is disposed in the middle portion of each support beam26in the height direction Z1, more specifically, substantially at the center in the height direction Z1. In addition, the connecting portion27connects the pair of support beams26and26to each other at one place in the height direction Z1.

As described above, the connecting portion27is disposed in the middle portion of the support beam26in the height direction Z1, whereby the workpiece transportation member24is formed in an H shape when viewed in the length direction X1. The position of the connecting portion27in the height direction Z1needs to be below the position of the upper end portion26u. For example, the distance from the upper end portion26umay be approximately ¼ of the height H1of the support beam26, may be approximately ½ of the height H1, or may be approximately ¾ of the height H1.

The connecting portion27is formed in a rectangular flat plate shape and extends horizontally along the length direction X1. The connecting portion27is disposed such that the height direction Z1becomes the thickness direction. With this configuration, the connecting portion27is horizontally disposed. In the present embodiment, the thickness (plate thickness) of the connecting portion27and the thickness (plate thickness) of the support beam26are the same as each other, but may be different from each other.

The connecting portion27and the support beam26are in contact with each other throughout the entire region of the support beam26in the length direction X1. The connecting portion27and the support beam26may be integrated by welding or may be integrally formed by rolling, forging, or the like. In a case where a large workpiece100is transported with the workpiece transportation fork22, the workpiece transportation member24may be formed of H-section steel.

The workpiece unloading device16is disposed on the downstream side of the workpiece loading device15and the heat treatment furnace2each having the above-described configuration in the transportation direction A1.

In the present embodiment, the workpiece unloading device16is configured to unload the workpiece100from one heater unit5at a time. The workpiece unloading device16unloads the workpiece100from the corresponding heater unit5through one of the plurality of opening parts4don the outlet side.

The workpiece unloading device16has a moving mechanism31and a workpiece transportation fork32.

The difference between the moving mechanism31and the moving mechanism21is that the moving mechanism21moves the workpiece transportation fork22in and out of the opening part4c. On the other hand, the moving mechanism31moves the workpiece transportation fork32in and out of the opening part4d. Since there is no significant difference between the configuration of the moving mechanism21and the configuration of the moving mechanism31except this point, the moving mechanism31will not be described in detail.

The configuration of the workpiece transportation fork32is the same as the configuration of the workpiece transportation fork22, including the fact that the workpiece transportation fork32has a plurality of the workpiece transportation members24. Therefore, the workpiece transportation fork32will not be described in detail.

For example, in a configuration where a first connecting portion configured to connect the upper portions of a plurality of support beams and a second connecting portion configured to connect the lower portions of the plurality of support beams are provided, the elongation amount of the first connecting portion and the elongation amount of the second connecting portion, which are attributed to radiation heat from workpieces, are different from each other. As a result, the support beam warps such that the elongation amount of the upper end portion of the support beam, which is attributed to radiation heat, becomes larger than the elongation amount of the lower end portion of the support beam.

Meanwhile, as described above, according to the present embodiment, the support beams26and26can be connected to each other with one connecting portion27. With such a configuration, it is possible to more reliably suppress the occurrence in the support beam26of the warpage of the workpiece transportation member24, particularly, warpage causing the elongation amount of the upper end portion26uof the support beam26, which is attributed to radiation heat from the workpiece100, to be larger than the elongation amount of the lower end portion26dof the support beam26. Moreover, since the workpiece transportation member24is formed of a single material, it is possible to further reduce the manufacturing cost of the workpiece transportation member24. In addition, it is possible to suppress the warpage of the workpiece transportation member24regardless of the heating pattern of the workpiece100and the heating temperature of the workpiece100. Therefore, it is not necessary to replace the workpiece transportation member24according to the workpiece100having a different heating pattern of the workpiece100and the like, and the same workpiece transportation member24can be used. Therefore, it is possible to decrease the replacement frequency of the workpiece transportation member24in the step of heat-treating the workpiece100, and thus a low cost relating to the transportation of workpieces is required, and it is possible to further improve the operating rate of the heat treatment device1.

In addition, according to the present embodiment, when heat coming from the workpiece100acts on the workpiece transportation member24, the workpiece transportation member24being deformed to warp downward is suppressed. Therefore, the total height of the workpiece transportation member24and the workpiece100placed on the workpiece transportation member24does not significantly change regardless of the temperature of the workpiece100. Therefore, at the time of transporting the workpiece100, the possibility of the workpiece transportation member24and the workpiece100coming into contact with the opening part4con the inlet side and the opening part4don the outlet side in the heat treatment furnace2becomes significantly low. As a result, a concern of the occurrence of a trouble of the heat treatment furnace2or the workpiece transportation member24being broken and a trouble of the workpiece100being damaged becomes significantly low.

In addition, according to the present embodiment, the connecting portion27connects the pair of support beams26and26to each other at one place in the height direction Z1. According to this configuration, it is possible to more reliably suppress the occurrence in the support beam26of the warpage of the workpiece transportation member24, particularly, warpage causing the elongation amount of the upper end portion26uof the support beam26to be larger than the elongation amount of the lower end portion26dof the support beam26.

In addition, according to the present embodiment, the number of the support beams26provided at an interval in the width direction Y1is two, and each support beam26is formed in a flat plate shape having the width direction Y1as the thickness direction. According to this configuration, it is possible to stably support the workpiece100with the two support beams26and26while the amount of heat transmitting from the workpiece100to the workpiece transportation member24is further reduced by further decreasing the contact area between the workpiece100and each support beam26.

In addition, according to the present embodiment, the connecting portion27is disposed in the middle portion of the support beam26in the height direction Z1, whereby the workpiece transportation member24is formed in an H shape when viewed in the length direction X1. According to this configuration, it is possible to realize the workpiece transportation member24having extremely high bending rigidity against the load of the workpiece100. In addition, since it is possible to decrease the projected area of the connecting portion27when viewed from the upper end side of the support beam26, it is possible to decrease the influence of radiation heat from the workpiece100. As a result, it is possible to more reliably suppress the warpage of the support beam26attributed to the radiation heat. Furthermore, it is possible to make the temperature distribution of the support beam26in the thickness direction (width direction Y1) of the support beam26, which is attributed to the conduction of heat from the workpiece100more even. Therefore, it is possible to more reliably suppress the occurrence of a temperature difference in the support beam26that causes large warpage.

In addition, according to the present embodiment, the connecting portion27is formed in a plate shape extending in the length direction X1. According to this configuration, the connecting portion27continuously extends in the length direction X1, whereby it is possible to further enhance the coupling stiffness between the connecting portion27and the support beam26. As a result, the workpiece transportation member24is capable of further decreasing the deflection amount (subduction amount) of the workpiece transportation member24on the tip end side when the workpiece100is placed on the workpiece transportation member24.

In addition, according to the present embodiment, the workpiece transportation fork22is formed of the workpiece transportation members24in which warpage attributed to heat from the workpiece100is suppressed. Therefore, when the workpiece100is placed on the workpiece transportation fork22, it is possible to more reliably suppress the occurrence of the warpage of the workpiece transportation fork22. In addition, since it is possible to suppress the warpage of the workpiece transportation fork22regardless of the heating pattern of the workpiece100and the like, it is not necessary to replace the workpiece transportation fork22according to the workpiece100having a different heating pattern of the workpiece100and the like, and the same workpiece transportation fork22can be used. Therefore, it is possible to decrease the replacement frequency of the workpiece transportation fork22in the heat treatment device1, and thus it is possible to further improve the operating rate of the heat treatment device1.

Hitherto, the embodiment of the present invention has been described, but the present invention is not limited to the above-described embodiment. The present invention can be modified in a variety of manners within the scope of the claims. It should be noted that, hereinafter, differences from the above-described embodiment will be mainly described, and the same configuration will be given the same reference numeral in drawings and will not be described in detail.

(1) In the above-described embodiment, the configuration where the workpiece transportation member24has an H shape has been described as an example. However, the configuration may not be as described above. Instead of the workpiece transportation member24, a U-shaped workpiece transportation member24A as shown inFIG.5(A)andFIG.5(B)may be used.FIG.5(A)is a cross-sectional view of the workpiece transportation member24A according to a first modification example, andFIG.5(B)is a perspective view of the workpiece transportation member24A shown inFIG.5(A). In this configuration, in the workpiece transportation member24A, the connecting portion27is adjacent to the lower end portions26dand26dof one pair of the support beams26and26and is fixed to the lower end portions26dand26d. That is, the difference between the workpiece transportation member24and the workpiece transportation member24A is the position of the connecting portion27in the height direction Z1. In addition, the connecting portion27is disposed in the lower end portion26dof the support beam26in the height direction Z1, whereby the workpiece transportation member24is formed in a U shape when viewed in the length direction X1.

As described above, in the heat treatment furnace2, the heater units5and5arranged vertically are not separated with a partition wall and directly face each other. Therefore, the workpiece transportation fork22that has been loaded into a predetermined heater unit5also receives radiation heat from the far-infrared heater11in the heater unit5directly below the predetermined heater unit5. However, the amount of radiation heat transmitting from directly below the heater unit5described above to the workpiece transportation fork22is smaller than the amount of radiation heat transmitting from the loaded heater unit5described above to the workpiece transportation fork22. Therefore, in the workpiece transportation member24A, even if the connecting portion27is disposed in the lower end portion26dof the support beam26, the heat elongation amount of the connecting portion27attributed to radiation heat from directly below the heater unit5described above is small.

As described above, according to the first modification example, the connecting portion27is disposed in the lower end portion26dof the support beam26in the height direction Z1, whereby the workpiece transportation member24A is formed in a substantially U shape when viewed in the length direction X1. According to this configuration, it is possible to realize the workpiece transportation member24A having sufficiently enhanced bending rigidity against the load of the workpiece100.

(2) In the above-described embodiment and modification example, the form where the connecting portion27has a flat plate shape that extends along the length direction X1has been described as an example. However, the form may not be as described above. For example, instead of the workpiece transportation members24and24A, a workpiece transportation member24B shown inFIG.6(A)or a workpiece transportation member24C shown inFIG.6(B)may be used.FIG.6(A)is a perspective view of the workpiece transportation member24B according to a second modification example, andFIG.6(B)is a perspective view of the workpiece transportation member24C according to a third modification example.

With reference toFIG.6(A)andFIG.6(B), in the second modification example, a plurality of connecting portions27B are provided at intervals in the length direction X1in the workpiece transportation member24B formed in an H shape when viewed in the length direction X1. Similarly, in the third modification example, a plurality of connecting portions27C are provided at intervals in the length direction X1in the workpiece transportation member24C formed in a U shape when viewed in the length direction X1.

The connecting portions27B and27C are each disposed at equal pitches in the length direction X1, but may be disposed at unequal pitches. The connecting portions27B and27C each extends straight in the width direction Y1, and both end portions of each of the connecting portions27B and27C are fixed to the corresponding support beams26. The shape of each of the connecting portions27B and27C may be a round bar shape, may be a square column shape, or may be a flat plate shape.

The plurality of connecting portions27B are provided at aligned positions in the height direction Z1and are disposed at, for example, the center of the support beam26in the height direction Z1. The position of each connecting portion27B in the height direction Z1is set in the same manner as the position of the connecting portion27. In addition, the plurality of connecting portions27C are provided at aligned positions in the height direction Z1and are disposed at, for example, the lower end portion26dof the support beam26in the height direction Z1.

With the above-described configuration, the connecting portions27B and27C connect the pair of support beams26and26to each other at one place in the height direction Z1. It should be noted that the positions of the plurality of connecting portions27B in the height direction Z1may not coincide with each other. For example, one connecting portion27B may be disposed at the center of the support beam26in the height direction Z1, and another connecting portion27B may be disposed close to the upper end portion26uor close to the lower end portion26dof the support beam26in the height direction Z1. Similarly, the positions of the plurality of connecting portions27C in the height direction Z1may not coincide with each other. For example, one connecting portion27C may be disposed at the lower end portion26dof the support beam26in the height direction Z1, and another connecting portion27C may be disposed close to the center of the support beam26in the height direction Z1.

As described above, according to the second modification example and the third modification example, the plurality of connecting portions27B and27C are each provided at intervals in the length direction X1. According to this configuration, the plurality of connecting portions27B or the plurality of connecting portions27C support the support beams26in cooperation with each other, whereby it is possible to further enhance the coupling stiffness between the connecting portion27B and27C and the corresponding support beam26. As a result, the workpiece transportation member24B and24C is capable of further decreasing the deflection amount of the workpiece transportation member24B and24C on the tip end side when the workpiece100is placed on the workpiece transportation member24B and24C. Furthermore, the connecting portions27B and27C are capable of reducing the amount of radiation heat received from the workpiece100. As a result, it is possible to more reliably suppress the warpage of the support beam26attributed to the radiation heat.

(3) In the above-described embodiment and the individual modification examples, the form where one pair of the support beams26are provided has been described as an example. However, the form may not be as described above. For example, instead of the workpiece transportation members24,24A,24B, and24C, a workpiece transportation member24D may be provided as shown inFIG.7.FIG.7is a schematic cross-sectional view of the workpiece transportation member24D according to a fourth modification example.

The workpiece transportation member24D has three support beams26. These support beams26are disposed at equal pitches or at unequal pitches in the width direction Y1. In addition, among the three support beams26, the support beams26facing each other in the width direction Y1are connected to each other with a connecting portion27D. A single connecting portion27D is formed in a flat plate shape and extends in the length direction X1or a plurality of connecting portions27D are provided at intervals in the length direction X1. The connecting portion27D needs to be disposed at a position below the position of the upper end portion26uof the support beam26in the height direction Z1, may be disposed at the center of the support beam26in the height direction Z1, or may be disposed at the lower end portion26dof the support beam26.

INDUSTRIAL APPLICABILITY

The present invention is widely applicable as workpiece transportation members, workpiece transportation devices, and heat treatment devices.

BRIEF DESCRIPTION OF THE REFERENCE SYMBOLS