JP2012211495A - Manufacturing device and method for boom of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing device and method for a boom of a construction machine, for improving the yield rate of products by applying more accurate bending work for upper and lower steel plates during manufacturing the boom to actualize accurate temporary assembly.SOLUTION: A bending work device 10 includes a hydraulic cylinder 11, a punch 13, supporting parts 14a, 14b, and a control part 20. The hydraulic cylinder 11 applies pressure to the flat surface of a workpiece W in a direction perpendicular thereto. The punch 13 performs bending work for the workpiece W while abutting on the workpiece W, using the hydraulic cylinder 11. The supporting parts 14a, 14b are disposed in opposition to the punch 13 for supporting the workpiece W during bending work using the punch 13. The control part 20 sets the position of the center of the workpiece W to be bent with a reference to the bending inflection point of a side plate.

Description

  The present invention relates to a boom manufacturing apparatus and a manufacturing method for a construction machine.

A work vehicle such as a hydraulic excavator includes a vehicle main body and a work machine attached to the vehicle main body.
The vehicle main body includes, for example, a lower traveling body and an upper revolving body that is turnably attached to the lower traveling body via a turning mechanism.
The work machine has a boom, an arm, and a bucket that are rotatably connected to each other, and is attached to the upper swing body. Such a work vehicle can perform various operations by swinging the boom, arm, and bucket driven by a drive device such as a hydraulic cylinder.

For example, Patent Document 1 discloses a jig for temporarily assembling a boom or an arm of a construction machine having a structure in which connecting portions are fixed to both ends in a longitudinal direction of a main portion composed of left and right side plates and a connecting material connecting them. It is disclosed.
Furthermore, Patent Document 2 discloses a boom mounting table device that can easily align the mounting portion of the boom with respect to the support portion of the work machine.

  By the way, at the time of manufacturing such a boom, after forming the left and right side plates including the bent portion by laser processing or the like, the upper plate and the lower plate are respectively bent according to the shape of the bent portion of the side plate. Is formed by welding. At this time, bending of the upper and lower plates is performed using a bending apparatus such as a roll bender on the basis of one end portion in the longitudinal direction.

JP 2002-188171 A (released July 5, 2002) JP 2004-195585 A (released July 15, 2004)

However, the conventional boom manufacturing apparatus for construction machinery has the following problems.
That is, in manufacturing a boom for a construction machine disclosed in the above publication, when a roll bender is used, bending of the upper and lower plates of the boom is performed with reference to one end portion in the longitudinal direction of the upper and lower plates. In a roll bender, bending is performed by pressing the rotated roll against the upper and lower plates while swinging, so the position of one reference end is likely to shift, and a dimensional error occurs at the opposite end of the upper and lower plates. There is a problem that concentrates.

For this reason, there exists a possibility that the up-and-down board bent by the state with low precision may be manufactured. Therefore, when the upper plate and the lower plate are combined with the left and right side plates and temporarily assembled, problems such as a decrease in the accuracy of temporary assembly and the inability to perform temporary assembly may occur.
An object of the present invention is to provide a boom manufacturing apparatus and a manufacturing method for a construction machine that can improve the yield of a product by performing accurate temporary assembly by improving the accuracy of bending during boom manufacturing. There is.

  A boom manufacturing apparatus for a construction machine according to a first invention is a boom manufacturing apparatus for bending a steel plate for upper and lower plates of a boom of a construction machine having a box structure in which upper and lower plates and side plates are combined. A part, a mold part, a support part, and a bending center position setting part. The pressing portion presses in a direction perpendicular to the plane of the upper and lower plate steel plates of the boom. The mold part bends the upper and lower plate steel plates in a state of being in contact with the upper and lower plate steel plates by the pressing portion. The support portion is disposed to face the mold portion, and supports the upper and lower plate steel plates when bending is performed by the mold portion. The bending center position setting unit sets the position of the bending center of the upper and lower plate steel plates based on the bending inflection point of the side plate.

Here, in the boom manufacturing apparatus for a construction machine having a box structure in which four plates (left and right side plates, upper plate, and lower plate) are combined, the side plate is formed in advance so as to include a bent portion by laser processing or the like. Based on the bending inflection point of (boom), the upper plate and the lower plate are bent using a press machine (pressing part, mold part).
Here, the upper and lower plate steel plates to be bent are workpieces (steel plates) for forming at least one of an upper plate and a lower plate constituting a box structure boom, each of which is a side plate. After being bent in accordance with the shape, a boom having a box structure is manufactured by welding to the upper and lower ends of the side plate in a temporarily assembled state.

Usually, when bending such steel sheets for upper and lower plates, a roll bender is used as a bending apparatus. In this roll bender, since bending is performed by rotating and swinging while pressing the roll against the upper and lower plate steel plates, there is a problem that the amount of bending tends to vary.
Furthermore, even when the upper and lower plate steel plates are bent using a press machine, in the bending process of the upper and lower plate steel plates, the cutting plate accuracy of the upper and lower plate steel plates is based on one end in the longitudinal direction. Since it is lower than the processing accuracy of the side plate, a large error occurs at the other end, and there is a possibility that the temporary assembly before welding cannot be performed accurately.

In the boom manufacturing apparatus for a construction machine according to the present invention, bending is performed using a press machine (pressing part, mold part), and the boom (side plate) is used as a reference position of the upper and lower steel plates when bending is performed. This is done based on the bending inflection point.
As a result, the bending inflection point of the boom is in the vicinity of the substantially central portion in the longitudinal direction. Therefore, when bending the upper and lower plate steel plates based on this inflection point, either end in the longitudinal direction is performed. The position shift due to the cutting plate accuracy of the upper and lower plate steel plates does not appear concentrated on the part. Therefore, the upper and lower plates and the side plates can be preliminarily assembled with high accuracy and welded to each other by performing highly accurate bending on the upper and lower plate steel plates. As a result, the manufacturing yield of the boom can be improved.

The boom manufacturing apparatus for a construction machine according to a second invention is the boom manufacturing apparatus for a construction machine according to the first invention, wherein when the upper and lower plate steel plates are pressed by the mold part, the mold part In addition, a die cushion disposed at a position where the upper and lower steel plates are sandwiched is further provided.
Thereby, since the position which becomes the bending center of the steel plate for upper and lower plates can be bent so as to be sandwiched with the mold part, the accuracy of the bending process can be improved.

The construction machine boom manufacturing apparatus according to a third aspect of the present invention is the construction machine boom manufacturing apparatus according to the first or second aspect of the present invention, wherein the detection unit detects the markings previously attached to the upper and lower plate steel plates. Is further provided. The bending center position setting unit sets the upper and lower plate steel plates below the mold unit with reference to the marking detected by the detection unit.
Thereby, for example, markings such as markings attached to the bending center position of the upper and lower plate steel sheets in advance before bending can be detected and set so that the bending center position is directly below the mold part.

  The boom manufacturing apparatus for a construction machine according to a fourth invention is the boom manufacturing apparatus for a construction machine according to any one of the first to third inventions, and conveys the upper and lower plate steel plates in the longitudinal direction. A transport unit is further provided. The bending center position setting unit measures the length of the upper and lower plate steel plates conveyed by the conveying unit, and the bending center position of the upper and lower plate steel plates is arranged below the mold part with reference to the bending inflection point of the side plate. As described above, a conveyance control unit that controls the conveyance unit is provided.

  Here, as the bending center position setting unit described above, a conveyance unit that conveys the upper and lower plate steel plates in the longitudinal direction and a conveyance that sets the bending center position of the upper and lower plate steel plates based on the bending inflection point of the boom (side plate). Using the control unit, the upper and lower plate steel plates to be bent are conveyed in the longitudinal direction so that the position to be the center of bending of the upper and lower plate steel plates is arranged according to the bending inflection point. Control is performed.

  As a result, the conveyance control unit determines that the position of the bending center in the upper and lower plate steel plates is directly below the mold portion based on the design bending inflection point of the boom (side plate) and the length of the upper and lower plate steel plates. The position of the upper and lower plate steel plates can be automatically set so as to be disposed in

The boom manufacturing apparatus for a construction machine according to a fifth invention is the boom manufacturing apparatus for a construction machine according to the fourth invention, wherein the bending center position setting unit is a steel plate for upper and lower plates conveyed by the conveying unit. It further has a detection sensor for detecting an end in the longitudinal direction.
Here, the detection sensor which detects the edge part of the steel plate for upper and lower plates conveyed by the conveyance part is provided.
Accordingly, when the upper and lower plate steel plates are transported in the longitudinal direction by the transport unit, the first and second ends are detected by detecting the first end in the longitudinal direction and the second end opposite to the first end. Based on the time difference at which the two ends are detected and the conveyance speed, the length of each upper and lower plate steel plate can be easily detected. Therefore, even when the cutting plate accuracy of the upper and lower plate steel plates is low, the bending process based on the bending inflection point of the boom (side plate) can be performed after accurately measuring the length of each upper and lower plate steel plate. it can.

A boom manufacturing apparatus for a construction machine according to a sixth invention is a boom manufacturing apparatus for a construction machine according to any one of the first to fifth inventions, and detects a bending angle of a steel plate for upper and lower plates. An angle sensor is further provided.
Here, as described above, when bending the upper and lower plate steel plates based on the bending inflection point of the boom (side plate), the bending angle is sensed by the angle sensor that detects the bending angle of the upper and lower plate steel plates. However, the mold part brought into contact with the upper and lower plate steel plates is advanced until a desired bending angle is obtained.
As a result, by performing the bending process while sensing the actual bending angle of the upper and lower steel plates, the accuracy is higher than when bending is performed only by the movement amount (pushing amount) of the mold part. Bending can be performed.

  A boom manufacturing apparatus for a construction machine according to a seventh aspect of the present invention is the boom manufacturing apparatus for a construction machine according to the sixth aspect of the present invention, further comprising a storage unit and a plate thickness estimation unit. A memory | storage part preserve | saves the table which shows the relationship between the bending angle and board thickness of the steel plate for upper and lower plates with respect to the moving amount | distance of a metal mold | die part. The plate thickness estimation unit estimates the plate thickness of the upper and lower plate steel plates based on the bending angle detected by the angle sensor and the movement amount of the mold unit.

Here, the amount of movement of the mold part and the actual bending angle are detected by using the fact that the bending angle with respect to the amount of movement of the mold part changes depending on the thickness of the upper and lower steel plates to be bent. Then, the plate thickness of the upper and lower plate steel plates is estimated.
Thereby, even when bending an object to be bent with different plate thicknesses, the bending can be performed with an optimum stroke amount (amount of movement of the mold part) according to each plate thickness. Therefore, even if it manufactures the boom of various construction machines comprised with the steel plate for upper and lower plates which differs in plate | board thickness, it can implement accurately.

A boom manufacturing apparatus for a construction machine according to an eighth invention is the boom manufacturing apparatus for a construction machine according to any one of the first to seventh inventions, wherein the bending machine is bent during upper and lower plate steel plate bending. A marking portion that performs marking at a central position is further provided.
Here, at the time of bending of the upper and lower plate steel plates, the marking portion marks the position that becomes the bending center of the upper and lower plate steel plates.

Here, as the marking part, for example, a laser or a protrusion marker provided near the support part can be used.
Accordingly, it is possible to easily mark the position that becomes the center of bending at the same time as the bending process is performed. Therefore, it is possible to perform a temporary assembly with high accuracy by combining the two side plates and the upper and lower plate steel plates in a state where the position of the bending center is accurately grasped.

The boom manufacturing apparatus for a construction machine according to a ninth invention is the boom manufacturing apparatus for a construction machine according to any one of the first to eighth inventions, wherein the mold part is formed with respect to the upper and lower plate steel plates. A support plate that supports at least one end of the upper and lower plate steel plates by moving so as to follow the steel plates for the upper and lower plate plates that are bent, I have.
Here, when the upper and lower plate steel plates are gradually bent by pressing the mold portion, the support is supported while moving so as to follow at least one end of the bent upper and lower plate steel plates. A board is provided.
As a result, even when bending a steel plate for upper and lower plates that is long in the longitudinal direction with respect to the width direction, it is possible to support at least one end while moving, thus preventing sagging of both ends due to the weight of the upper and lower plate steel plates. Thus, a highly accurate bending process can be performed.

  A method for manufacturing a boom for a construction machine according to a tenth invention uses a press machine including a pressing portion, a mold portion pushed by the pressing portion, and a support portion disposed at a position facing the mold portion. A method of manufacturing a boom for bending a steel plate for an upper and lower plate of a boom of a construction machine having a box structure in which an upper and lower plate and a side plate are combined, the step of setting the upper and lower plate steel plate on a support portion; A step of setting a bending center position of the steel plate with reference to a bending inflection point of the side plate, and a step of pressing and pressing the mold part to a position to be a bending center in the upper and lower plate steel plates to perform bending processing. Yes.

Here, in the boom manufacturing apparatus for a construction machine having a box structure in which four plates (left and right side plates, upper plate, and lower plate) are combined, the side plate is formed in advance so as to include a bent portion by laser processing or the like. Based on the bending inflection point of (boom), the upper plate and the lower plate are bent using a press machine (pressing part, mold part).
Here, the upper and lower plate steel plates to be bent are workpieces (steel plates) for forming at least one of an upper plate and a lower plate constituting a boom having a box structure, After being bent according to the shape of the side plate, it is fixed to the upper and lower ends of the side plate by welding in a temporarily assembled state, and a boom having a box structure is manufactured.

Usually, when bending such steel sheets for upper and lower plates, a roll bender is used as a bending apparatus. In this roll bender, since bending is performed by rotating and swinging while pressing the roll against the upper and lower plate steel plates, there is a problem that the amount of bending tends to vary.
Furthermore, even when the upper and lower plate steel plates are bent using a press machine, in the bending process of the upper and lower plate steel plates, the cutting plate accuracy of the upper and lower plate steel plates is based on one end in the longitudinal direction. Since it is lower than the processing accuracy of the side plate, a large error occurs at the other end, and there is a possibility that the temporary assembly before welding cannot be performed accurately.

In the boom manufacturing apparatus for a construction machine according to the present invention, bending is performed using a press machine (pressing part, mold part), and the boom (side plate) is used as a reference position of the upper and lower steel plates when bending is performed. This is done based on the bending inflection point.
As a result, the bending inflection point of the boom is in the vicinity of the substantially central portion in the longitudinal direction. Therefore, when bending the upper and lower plate steel plates based on this inflection point, either end in the longitudinal direction is performed. The position shift due to the cutting plate accuracy of the upper and lower plate steel plates does not appear concentrated on the part. Therefore, the upper and lower plates and the side plates can be preliminarily assembled with high accuracy and welded to each other by performing highly accurate bending on the upper and lower plate steel plates. As a result, the manufacturing yield of the boom can be improved.

  According to the boom manufacturing apparatus for a construction machine according to the present invention, by performing highly accurate bending on the upper and lower plate steel plates, the upper and lower plates and the side plates are temporarily assembled together and welded together, The production yield of the boom can be improved.

The front view which shows the bending apparatus which concerns on one Embodiment of this invention. The control block diagram formed in the control part of the bending apparatus of FIG. The flowchart which shows the flow of the manufacturing method of the boom by the bending apparatus of FIG. The front view which shows the state in which the workpiece | work (upper / lower board) was carried in to the bending apparatus of FIG. (A), (b) is a top view which shows setting the position of a bending center by comparing the size of the workpiece | work on drawing, and the size of the workpiece | work actually carried in. The front view which shows the state in which the workpiece | work was set so that the bending center position may be just under a metal mold | die part in the bending apparatus of FIG. The front view which shows the state which presses in the state which made the metal mold | die part contact | abut in the bending center position in the bending apparatus of FIG. 1, and performs a bending process. Explanatory drawing explaining the angle of the bending process by the bending apparatus of FIG. The top view which shows the surface of the upper and lower plates marked by the protrusion marker when bent by the bending apparatus of FIG. (A)-(e) is a figure which shows the flow at the time of carrying out temporary assembly combining the upper and lower plates and the side plate which were bent by the bending apparatus of FIG. The flowchart which shows the flow of the plate | board thickness estimation of the steel plate by the bending apparatus of FIG. The front view which shows the structure of the bending apparatus which concerns on other embodiment of this invention.

A boom manufacturing apparatus and manufacturing method for a construction machine according to an embodiment of the present invention will be described below with reference to FIGS.
In the present embodiment, the boom is manufactured as a part of a work machine in a construction machine such as a hydraulic excavator and has a box structure in which left and right side plates, a lower plate, and an upper plate are combined. The processes from the process of bending the workpiece (steel plate for upper and lower plates) W to the temporary assembly and welding according to the shape of the bent portion of the (side plate) will be described.
Here, the workpiece W is a steel plate that is subjected to processing such as bending as upper and lower plates, and has a thickness of about 8 mm to 16 mm. In this embodiment, the state of the upper plate or the lower plate until it is temporarily assembled with the left and right side plates is referred to as a workpiece W.

[Configuration of entire bending apparatus 10]
A bending apparatus (a manufacturing method of a boom of a construction machine) 10 according to the present embodiment has a bent portion of a boom with respect to a steel plate (work W) serving as upper and lower plates Wa and Wb constituting a box structure of a boom B. As shown in FIG. 1, a hydraulic cylinder (pressing part) 11, an upper ram 12, a punch (die part) 13, support parts 14a and 14b, angle sensors 15a and 15b, Die cushion 16, support plates 17a and 17b, guide rollers 18a and 18b, control unit (bending center position setting unit, conveyance control unit, plate thickness estimation unit, push-in amount setting unit) 20, conveyance unit 21, photoelectric tube (detection sensor) 22 and a storage unit 30.

The hydraulic cylinder 11 moves the punch 13 in a direction perpendicular to the plane of the workpiece W, and presses the workpiece 13 with the punch 13 in contact with the workpiece W, thereby bending the workpiece W into a desired shape. To do.
The upper ram 12 is provided between the hydraulic cylinder 11 and the punch 13 and reciprocates in the vertical direction together with the punch 13 during bending.

The punch (die part) 13 is bent by moving in contact with the workpiece W to be bent. Further, the punch 13 has a curved portion that defines a bending angle on the side in contact with the workpiece W.
The support portions 14a and 14b are a pair of support bases that support the work W from below, and are disposed so as to sandwich the die cushion 16 disposed at the pressing center position X.

The angle sensors 15a and 15b are provided at the tip portions of the support portions 14a and 14b, that is, the support plates 17a and 17b that support the workpiece W, and the bending angle of the workpiece W based on the rotation angle of the support plates 17a and 17b. Is detected.
The die cushion 16 is disposed on the pressing center position X pressed by the punch 13 and supports the bending center position of the workpiece W from below. Further, the die cushion 16 can move up and down as the punch 13 descends, and moves downward with respect to the support portions 14 a and 14 b with the workpiece W sandwiched between the die cushion 16 and the punch 13. Then, the workpiece W is bent. Furthermore, the die cushion 16 has a protrusion marker 16a that marks the position of the bending center position C on the surface facing the workpiece W. The protrusion markers 16 a are protrusion-like members that protrude toward the surface of the workpiece W, and three protrusion markers 16 a are provided along the width direction of the workpiece W. Thereby, the mark (mark) M (refer FIG. 9) can be provided to the position of the bending center in the workpiece W bent by the bending apparatus 10. For this reason, it is possible to set the workpiece W in the temporary assembly device 50 after accurately grasping the bending center position in a temporary assembly step described later.

  The support plates 17a and 17b support both ends of the work W from below, and when the work W is bent as the punch 13 descends, the support plates 17a and 17b rotate around the rotation axis, thereby allowing the work W to be bent during the bending process. It rotates following the movement of both ends. In other words, the support plates 17a and 17b are arranged along the horizontal direction when the workpiece W before bending is carried in, and support from below while being in contact with both ends of the workpiece W as the bending progresses. It rotates as follows.

  The guide rollers 18a and 18b are arranged above the support plates 17a and 17b via a predetermined gap in order to guide the workpiece W in a desired direction when the workpiece W is conveyed onto the support plates 17a and 17b. Has been. The guide rollers 18a and 18b are moved to a predetermined retracted position by a hydraulic cylinder (not shown) after the workpiece W is loaded and positioned on the support plates 17a and 17b.

  The control unit 20 performs overall control of the bending apparatus 10 and is connected to the angle sensors 15a and 15b, the transport unit 21 and the photoelectric tube 22 as shown in FIG. Moreover, the control part 20 implements the bending process of the workpiece | work W according to the flowchart shown in FIG. The control block formed by the control unit 20 and the details of the control will be described in detail later.

As shown in FIG. 4, the conveyance unit 21 is a conveyance device that conveys the workpiece W before bending onto the support portions 14a and 14b, and conveys the workpiece W in a desired direction by a plurality of conveyance rollers 21a. .
The photoelectric tube (detection sensor) 22 is disposed between the transport unit 21 and the support units 14a and 14b, and irradiates light from below onto the work W transported by the transport unit 21, and reflects the reflected light. The end of the workpiece W is detected depending on whether or not it is detected.

  The storage unit 30 indicates the relationship between the bending angle of the workpiece W and the plate thickness with respect to the data of the dimension (length, width, bending center position, etc.) of the workpiece W on the drawing and the stroke amount (movement amount) of the punch 13. Each table is stored. These tables include, for example, a first table that shows the relationship between the bending angle and the plate thickness, and a second table that shows the relationship between the plate thickness and the pressing amount of the punch 13.

(Control unit 20)
In the present embodiment, the control unit 20 reads various programs stored in the storage unit 30, and as shown in FIG. 2, the bending center position setting unit 20a, the plate thickness estimation unit 20b, the conveyance control unit 20c, A push amount setting unit 20d is formed.
The conveyance control unit 20 c performs conveyance control when conveying the workpiece W into the bending apparatus 1 along the longitudinal direction at a predetermined conveyance speed. In addition, the conveyance control unit 20 c controls the conveyance of the workpiece W so that the photoelectric tube 22 can detect the front end portion and the rear end portion of the workpiece W that are necessary when measuring the length of the workpiece W.

  The bending center position setting unit 20 a measures the actual length of the workpiece W conveyed by the conveyance unit 21 based on the timing when both ends of the workpiece W are detected in the photoelectric tube 22 and the conveyance speed in the conveyance unit 21. . Then, the bending center position setting unit 20a compares the actual length of the measured workpiece W with the upper and lower plates W1 on the drawing (see FIG. 5A), and the bending center position of the upper and lower plates W1 on the drawing. Based on C, the position C ′ of the bending center of the workpiece W that has been conveyed is set.

Here, the steel plate (work W) that is the object of bending is generally one having low cutting plate accuracy, and the length varies. Therefore, in this embodiment, the position of the bending center can be accurately set by automatically measuring the dimension (length) in the longitudinal direction of each steel plate before bending.
Specifically, as shown in FIGS. 5A and 5B, when there is a difference d in the length of the workpiece W conveyed compared to the length of the upper and lower plates W1 on the drawing. Sets the bending center position of the workpiece W at a position moved to the right by d / 2 with reference to the bending center position C of the upper and lower plates W1 on the drawing. Even when the length of the workpiece W is smaller than the length of the upper and lower plates W1 on the drawing, the bending center position can be similarly set.

Thereby, even when the cutting plate accuracy of the steel plate to be bent is low, the position of the bending center can be set accurately.
The plate thickness estimation unit 20b is currently performing bending processing based on a predetermined punch movement amount set in advance and a first table indicating the relationship between the bending angle and the plate thickness stored in the storage unit 30. The thickness of the workpiece W is measured. The predetermined punch movement amount means the movement amount from the position where the punch 13 is at the movement origin.

  Specifically, the punch 13 is lowered until it abuts against the workpiece W set on the support portions 14a and 14b (see FIG. 6), and further lowered, as shown in FIG. Both ends of the are lifted. Here, the support plates 17a and 17b support both ends of the workpiece W being bent from below by rotating about the rotation axis so as to follow both ends of the workpiece W being lifted.

At this time, when the punch 13 reaches a predetermined movement amount, the plate thickness estimation unit 20b acquires the bending angle detected by the angle sensors 15a and 15b. And the plate | board thickness estimation part 20b is based on the 1st table which shows the relationship between the bending angle and workpiece | work thickness of the workpiece | work W stored in the memory | storage part 30, and currently the plate | board thickness of the workpiece | work W in the bending downward | lowering presume.
The pushing amount setting unit 20d refers to the second table showing the relationship between the plate thickness of the workpiece W plate and the pushing amount of the punch 13 based on the plate thickness of the workpiece W estimated by the plate thickness estimation unit 20b. The final push amount of the punch 13 is set. In other words, the pushing amount setting unit 20d sets the optimum pushing amount of the punch 13 with respect to the thickness of the workpiece W in consideration of the influence of the spring back that occurs after the bending process that varies depending on the thickness of the workpiece W. Thereby, the bending state of the workpiece | work W after a bending process can be brought close to a desired shape.

<Bending of upper and lower plates>
In the bending apparatus 10 of this embodiment, bending is performed according to the flowchart shown in FIG. 3 using the configuration described above.
First, in step S <b> 1, the workpiece W is transported toward the support portions 14 a and 14 b by the transport unit 21 in the bending apparatus 10.

  In step S2, the dimension (length) in the longitudinal direction of the workpiece W is measured at the timing at which the leading end and the trailing end of the workpiece W conveyed along the longitudinal direction at a predetermined conveying speed are detected. Specifically, the length of the workpiece W is measured based on the time difference at which the leading end portion and the trailing end portion of the workpiece W are detected and the conveyance speed. Therefore, in the present embodiment, when the work W is loaded, the work W is once transported until the rear end portion of the work W passes the upper part of the phototube 22, and the bending center position of the work W is set to the pressing center position X. The workpiece W is again conveyed in a desired direction so as to match.

  In step S3, the length of the workpiece W measured in step S2 is compared with the length of the upper and lower plates W1 on the drawing to set the position of the bending center position C ′ of the workpiece W. Specifically, as shown in FIGS. 5A and 5B, in the case of a difference in length d between the workpiece W and the upper and lower plates W1 on the drawing, dimensional errors are respectively present at both ends of the workpiece W. The bending center position C ′ of the workpiece W is set at a position to the right by d / 2 so that is distributed.

In step S4, as shown in FIG. 6, the conveyance unit 21 is controlled so that the bending center position C ′ set in step S3 is on the pressing center position X of the bending apparatus 50.
Thereby, a bending process can be implemented in a state where the bending center position C ′ set for each workpiece W and the pressing center position X of the bending apparatus 10 are matched. As a result, when bending the workpiece W having a variation in length, the dimensional error is dispersed at both ends as compared with the case where the bending is performed with one end as a reference. The dimensional error does not concentrate on the end of the. Therefore, the manufacturing yield of the boom can be improved.

In step S5, the punch 13 is pressed while being in contact with the upper surface of the workpiece W.
In step S6, it is determined whether or not the punch 13 has reached a predetermined movement amount. Here, when the punch 13 reaches a predetermined movement amount, the lowering of the punch 13 is temporarily stopped, and the process proceeds to step S7.
In step S7, the thickness of the workpiece W is determined by referring to the first table stored in the storage unit 30 based on the predetermined amount of movement of the punch 13 and the output values from the angle sensors 15a and 15b at this time. Is estimated.

Specifically, as shown in the flowchart of FIG. 11, when the punch 13 reaches a predetermined movement amount in step S21, in step S22, the control unit 20 detects the workpiece W at that time from the angle sensors 15a and 15b. Get the bending angle.
Next, in step S <b> 23, the control unit 20 accesses the storage unit 30.
Next, in step S24, the control unit 20 estimates the plate thickness of the workpiece W being bent with reference to the first table based on the movement amount of the punch 13 and the bending angle.

In step S8, the final movement of the punch 13 is determined by referring to the second table showing the relationship between the thickness of the workpiece W and the amount of pressing of the punch 13 based on the thickness of the workpiece W estimated in step S7. The amount is set, and the punch 13 once stopped is moved again.
In step S9, as shown in FIG. 7, the punch 13 is moved until the final push amount (movement amount) set in step S8 is reached. When the final movement amount is reached, the process proceeds to step S10. .

Here, the magnitude of the spring back of the workpiece W after bending by the bending apparatus 10 (the force for returning to the state before bending) varies depending on the plate thickness. Specifically, when the plate thickness of the workpiece W is large, the amount of spring back is large. Conversely, when the plate thickness is small, the amount of spring back is small.
In the bending apparatus 10 of the present embodiment, as shown in FIG. 8, the bending shape at the time of bending takes into account the degree of springback after bending, which varies depending on the thickness of the workpiece W. The bending angle θ1 is set in the circle having the radius R1. That is, the bending shape is determined by the R surface of the punch 13 and the bending angle. As shown in FIG. 8, the bending curve line of the boom is a part of a circle having a radius R2 and an arc portion having a central angle θ2. Then, in this embodiment, the bending curve line at the time of bending is set to be a part of a circle with a radius R1 and an arc part with a central angle θ1. The relationship between R1, R2 and θ1, θ2 satisfies the following relational expression.
R1 × θ1 = R2 × θ2

Thereby, the amount of spring back according to the plate | board thickness of the workpiece | work W can be considered, and the bending process of the workpiece | work W with high precision can be implemented. Therefore, in the temporary assembly process described later, when the upper and lower plates Wa and Wb are clamped, the left and right side plates S can be accurately aligned.
The bending process of the workpiece W is completed through the above steps. At this time, as shown in FIG. 9, three marks (marks) M formed by the protrusion markers 16a provided at the pressing center position (bending center position) are formed on the workpiece W after bending.

In step S10, the left and right side plates S and the upper and lower plates Wa are used by using the temporary assembly device 50 shown in FIG. 10A with reference to the mark M formed at the bending center position of the workpiece W during bending. , Wb are temporarily assembled and temporary welding is performed.
Specifically, first, the bent workpiece W (lower plate Wa) is set on the jigs 51a to 51e. At this time, the lower plate Wa is set so that the position of the mark (mark) M (bending center position) of the lower plate Wa matches the temporary assembly center position Y in the temporary assembly device 50.

Next, as shown in FIG. 10B, the lower plate Wa is clamped on the jigs 51a to 51e.
Next, as shown in FIG. 10C, the left and right side plates S, S are set with reference to the temporary assembly center position Y. At this time, the left and right side plates S, S are clamped from both the left and right sides using a jig (not shown).
Next, as shown in FIG. 10D, connecting portions 52 and 53 provided at both ends of the boom are set. The connection parts 52 and 53 are cast products.

Next, as shown in FIG. 10E, the upper plate Wb is set on the left and right side plates S, S. At this time, the upper plate Wb is clamped from above using a jig (not shown). In this state, the lower plate Wa and the upper plate Wb are temporarily welded to the left and right side plates S, S and fixed.
In step S11, as shown in FIG. 10 (e), the temporarily welded left and right side plates S, S and the upper and lower plates Wa, Wb are fixed by main welding, so that the boom having a box structure with high accuracy can be obtained. Can be manufactured.

[Other Embodiments]
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.
(A)
In the above-described embodiment, the example in which the setting of the bending center position of the workpiece W is automatically performed by the conveyance control by the control unit 20 has been described. However, the present invention is not limited to this.

For example, the length of the workpiece W is previously measured off-line in advance, and an inscription (marking, mark) is put at a position that becomes the bending center, and the CCD camera (detection unit) 122 is placed on the transport unit 21 as shown in FIG. The bending apparatus 110 may be provided with optical means such as (including a recognition means here).
In this case, the mark is recognized by the CCD camera 122 during conveyance of the workpiece W, and a recognition signal is output to the control unit 20 (conveyance control unit 20c). And when the workpiece | work W is conveyed by the predetermined speed, the control part 20 (conveyance control part 20c) receives a recognition signal, and stops conveyance after predetermined time passes, A bending center position is set to the center part of the punch 13. FIG. Can be set.

(B)
In the said embodiment, the example of implementing the setting of the bending center position at the time of implementing the bending process of the workpiece | work W by the conveyance control of the conveyance part 21 which conveys the workpiece | work W to a longitudinal direction was given and demonstrated. However, the present invention is not limited to this.
For example, before the bending process is performed, when a marking process is applied to the bending center position in another apparatus or the like, the position of the bending center is set using a sensor or the like that detects the marking. It may be.

(C)
In the said embodiment, the example which used the processus | protrusion marker 16a was given and demonstrated as a marking part for marking the position of the bending center of an up-and-down board. However, the present invention is not limited to this.
For example, other marking means such as a laser marker may be used.
Also, the marking position and the number of marks can be changed as appropriate.

(D)
In the embodiment described above, an example in which the photoelectric tube 22 that detects both ends in the longitudinal direction of the workpiece W is provided in order to measure the length of the workpiece W has been described. However, the present invention is not limited to this.
For example, the length of the work W may be measured by detecting the position of the rear end in a state where the front end of the work W is in contact with a predetermined position.

(E)
In the embodiment described above, an example in which the plate thickness of the workpiece W is estimated based on the bending angle of the workpiece W with respect to a predetermined punch movement amount, and the final pressing amount of the punch 13 is set based on the thickness is described. . However, the present invention is not limited to this.

For example, the workpiece thickness may be measured using a means such as a height sensor that can directly measure the workpiece thickness, and the final punch push-in amount may be set based on the measurement result.
Even in this case, it is possible to obtain an effect similar to that of the above-described embodiment in which an optimum punch push-in amount can be set according to the plate thickness.
In this case, since the plate thickness of the workpiece is known in advance, the step for estimating the plate thickness of the workpiece is not required as in the above embodiment. Therefore, the punch may be controlled to move by a predetermined movement amount (stroke amount) from the state where the punch is in contact with the surface of the workpiece. As for the timing at which the punch comes into contact with the surface of the workpiece, the timing at which the reaction force applied to the punch is detected may be used as it is.

(F)
In the embodiment described above, an example in which the angle sensors 15a and 15b that detect the bending angle of the workpiece W based on the rotation angles of the support plates 17a and 17b are used as the sensors that detect the bending angle of the workpiece W has been described. However, the present invention is not limited to this.
For example, an angle sensor that detects the inclination of the support plate attached to the support plate may be used.

  The boom manufacturing apparatus and manufacturing method for a construction machine according to the present invention perform a highly accurate bending process on the upper and lower plates, temporarily assemble the upper and lower plates and the side plates with high accuracy, and weld each other. Since the production yield can be improved, it is widely applicable to the production of booms mounted on various construction machines.

10 Bending machine (Production equipment for construction machinery boom)
11 Hydraulic cylinder (pressing part)
12 Upper ram 13 Punch (die part)
14a, 14b Support portions 15a, 15b Angle sensor 16 Die cushion 16a Protrusion marker (marking portion)
17a, 17b Support plates 18a, 18b Guide roller 20 Control unit 20a Bending center position setting unit 20b Plate thickness estimation unit 20c Transport control unit 20d Push amount setting unit 21 Transport unit 21a Transport roller 22 Photoelectric tube (detection sensor)
30 Storage Unit 50 Temporary Assembly Device 51 Jig 52 Connection Portion 53 Connection Portion 110 Bending Device (Construction Machine Boom Manufacturing Device)
122 CCD camera (detector)
C Bending center position d Difference M Mark
S side plate W work (steel plate for upper and lower plates)
Wa Lower plate Wb Upper plate W1 Upper and lower plates on the drawing X Press center position Y Temporary assembly center position R1, R2 Radius θ1, θ2 Center angle

Claims (10)

A boom manufacturing apparatus for bending a steel plate for upper and lower plates of a boom of a construction machine having a box structure in which upper and lower plates and side plates are combined,
A pressing portion that presses in a direction perpendicular to the plane of the steel plate for the upper and lower plates of the boom; and
A mold portion for bending the upper and lower plate steel plates in a state of being in contact with the upper and lower plate steel plates by the pressing portion;
A support portion that is disposed opposite to the mold portion and supports the upper and lower plate steel plates when bending is performed by the mold portion;
A bending center position setting unit for setting the position of the bending center of the upper and lower plate steel plates based on the bending inflection point of the side plate;
Boom manufacturing equipment for construction machinery. When the upper and lower plate steel plates are pressed by the mold portion, a die cushion disposed at a position sandwiching the upper and lower plate steel plates together with the mold portion,
In addition,
The apparatus for manufacturing a boom for a construction machine according to claim 1. It further comprises a detection unit that detects markings previously attached to the upper and lower plate steel plates,
The bending center position setting unit sets the upper and lower plate steel plates below the mold unit with reference to the marking detected in the detection unit,
The apparatus for manufacturing a boom for a construction machine according to claim 1 or 2. A transport unit for transporting the upper and lower plate steel plates in the longitudinal direction;
In addition,
The bending center position setting unit measures the length of the upper and lower plate steel plates conveyed by the conveying unit, and the bending center position of the upper and lower plate steel plates is based on the bending inflection point of the side plate. A conveyance control unit that controls the conveyance unit so as to be arranged below the unit,
The boom manufacturing apparatus for a construction machine according to any one of claims 1 to 3. The bending center position setting unit further includes a detection sensor that detects an end in the longitudinal direction of the upper and lower plate steel plates conveyed by the conveyance unit.
The apparatus for manufacturing a boom for a construction machine according to claim 4. An angle sensor for detecting a bending angle of the upper and lower plate steel plates;
In addition,
The manufacturing apparatus of the boom of a construction machine of any one of Claim 1 to 5. A storage unit for storing a table indicating a relationship between a bending angle and a plate thickness of the upper and lower plate steel plates with respect to a movement amount of the mold unit;
Based on the bending angle detected by the angle sensor and the amount of movement of the mold part, a plate thickness estimation unit that estimates the plate thickness of the upper and lower plate steel plates;
Further equipped with,
The apparatus for manufacturing a boom for a construction machine according to claim 6. When bending the upper and lower plate steel plates, a marking portion that performs marking at a position that becomes a bending center,
In addition,
The apparatus for manufacturing a boom for a construction machine according to any one of claims 1 to 7. When performing the bending process in a state where the mold part is in contact with the upper and lower plate steel plates, the upper and lower plate steel plates move so as to follow the bent upper and lower plate steel plates. A support plate for supporting at least one end of
In addition,
The apparatus for manufacturing a boom for a construction machine according to any one of claims 1 to 8. A box structure in which a steel plate for upper and lower plates and a side plate are combined by using a press machine including a pressing portion, a mold portion pushed by the pressing portion, and a support portion disposed at a position facing the mold portion. A boom manufacturing method for bending a steel plate for upper and lower plates of a boom of a construction machine having:
Setting the steel plate for upper and lower plates on a support part;
Setting the bending center position of the upper and lower plate steel plates based on the bending inflection point of the side plate;
A step of pressing and pressing the mold part at a position to be the bending center in the upper and lower plate steel plates;
A method for manufacturing a boom for a construction machine comprising:

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