Forging material travel distance measurement system, travel distance measurement method, and forged product manufacturing method

Abstract

To provide a movement distance measurement system of a forging material which improves measurement accuracy of a movement distance of a forging material by directly obtaining a movement distance of the forging material from the forging material, a movement distance measurement method and a manufacturing method of a forged product.SOLUTION: A movement distance measurement system 10 comprises: a distance meter 12 which is used in a forging device 1 having a manipulator 2 that grasps a longitudinal direction one end 100a of a forging material 100 extending in the longitudinal direction to move the same in the longitudinal direction and which measures a distance L1 to an end surface 100d on the longitudinal direction other end 100b side of the forging material 100 before the forging material 100 moves from the distance meter 12 and a distance L2 to the end surface 100d on the longitudinal direction other end 100b side of the forging material 100 after the forging material 100 moves from the distance meter 12; and a movement distance calculation device 13 which calculates an actual movement distance L in the longitudinal direction of the forging material 100 on the basis of the distance L1 before the forging material 100 moves and the distance L2 after the forging material 100 moves measured by the distance meter 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a system and method for measuring the travel distance of a forged material in a free forging process for producing forged materials such as forged products, and a method for measuring the travel distance, and a method for manufacturing a forged product. [Background technology]

[0002] Generally, in the free forging process for producing forged products such as forged parts, a forging device is used that is equipped with a manipulator that grips and moves the forging material (raw material) that extends in the longitudinal direction, and a forging press that presses down the forging material, as shown in Non-Patent Document 1, for example. Here, the longitudinal reduction position of the forged material in the forging press is determined by the intended use of the product and the final shape of the product, and has a significant impact on the forged product, so the amount of movement (travel distance) of the forged material by the manipulator is very important. Patent Document 1 proposes a control method for a forging manipulator. In this control method, two manipulator carriages linked to a forging press are each equipped with a workpiece gripping device that grips both ends of the forging material and is movable relative to the manipulator carriage. The manipulator carriages are also equipped with a first position detector that detects the relative position of the workpiece gripping device and the manipulator carriage, and a second position detector that detects the traveling position of the manipulator carriage. The first position detector calculates the sum of the displacements of the workpiece gripping devices of the two manipulators due to the elongation of the forging material, and the slave control device compares this to generate a correction signal. Meanwhile, the signal from the second position detector is input to a master control device to generate a manipulator position control signal and a reference signal. These signals are used to control the movement of the master and slave manipulator carriages as the two manipulator carriages sequentially feed the forging material into the forging press. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Kakimoto et al., "Process Design Technology for Forging and Stretching," Research Development KOBE STEEL ENGINEERING REPORTS, vol. 60 No. 2, pp. 2-8 [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 60-92033 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional forging manipulator control method disclosed in Patent Document 1 has the following problems. That is, in the case of the forging manipulator control method shown in Patent Document 1, the movement distance of the forging material is not obtained directly from the forging material, but the relative position of the material grasping device and the manipulator cart is detected by a first position detector mounted on the manipulator cart. Also, the traveling position of the manipulator cart is detected by a second position detector mounted on the manipulator cart, and the movement distance of the forging material is detected from this information. As a result, there is a problem that the accuracy of the detected movement distance of the forging material is low, and the dimensional accuracy of the manufactured forged product is low.

[0006] In other words, when the forging press reduces the forging material, the material gripping mechanism of the manipulator moves slightly due to the impact of the reduction, reducing the accuracy of the detected distance the forging material has traveled. Also, when the forging press reduces the forging material, the wheels of the manipulator carriage move slightly due to the impact of the reduction, reducing the accuracy of the detected distance the forging material has traveled. As a result, the reduction is not performed at the specified position, and the dimensional accuracy of the product also decreases. Therefore, the present invention has been made to solve this conventional problem, and its object is to provide a forging material travel distance measurement system, a travel distance measurement method, and a forged product manufacturing method that can improve the measurement accuracy of the forged material travel distance by obtaining the forged material travel distance directly from the forged material, and ultimately improve the dimensional accuracy of the forged product. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, one aspect of the present invention provides a forging movement distance measurement system for use in a forging device that includes a manipulator that grips one longitudinal end of the forging and moves it in the longitudinal direction, and a forging press that presses down the forging. The system measures the distance from a distance meter to the end face of the other longitudinal end of the forging opposite to the one longitudinal end gripped by the manipulator before the forging moves, and the distance from a distance meter to the end face of the other longitudinal end of the forging opposite to the one longitudinal end gripped by the manipulator after the forging moves. The gist of the present invention is that the apparatus includes a range finder that measures the distance to the end face of the other longitudinal end of the forged material opposite to the one longitudinal end held by the manipulator in the longitudinal direction, and a movement distance calculation device that calculates the actual movement distance of the forged material in the longitudinal direction based on the distance measured by the range finder from the range finder to the end face of the other longitudinal end of the forged material before the forged material moves, and the distance measured by the range finder from the range finder to the end face of the other longitudinal end of the forged material after the forged material moves.

[0008] Another aspect of the present invention is a method for measuring the movement distance of a forged material when manufacturing a forged product using a forging device that includes a manipulator that grips one longitudinal end of the forged material and moves it in the longitudinal direction, and a forging press that presses down the forged material. The method measures the distance from a distance meter to the end face of the other longitudinal end of the forged material opposite to the one longitudinal end gripped by the manipulator before the forged material moves, and the distance from a distance meter to the end face of the longitudinal end of the forged material after the forged material moves. The method includes a distance measuring step of measuring the distance to the end face of the other longitudinal end side opposite to the one longitudinal end side grasped by the manipulator using the range finder, and a movement distance calculation step of calculating the actual movement distance of the forged material in the longitudinal direction based on the distance measured in the distance measuring step from the range finder to the end face of the other longitudinal end side of the forged material before the forged material moves and the distance measured from the range finder to the end face of the other longitudinal end side of the forged material after the forged material moves.

[0009] A method for manufacturing a forged product according to another aspect of the present invention is characterized in that the forged product is manufactured using the above-mentioned method for measuring the travel distance of a forged material. [Effects of the Invention]

[0010] According to the forged material travel distance measurement system, travel distance measurement method, and forged product manufacturing method of the present invention, it is possible to provide a forged material travel distance measurement system, travel distance measurement method, and forged product manufacturing method that can improve the measurement accuracy of the forged material travel distance by obtaining the forged material travel distance directly from the forged material, and ultimately improve the dimensional accuracy of the forged product. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a forging material travel distance measurement system and a forging device according to an embodiment of the present invention; [Figure 2] 2 is a diagram showing an example of a display screen of a display device constituting the travel distance measuring system shown in FIG. 1. FIG. [Figure 3]2 is a flowchart illustrating a process flow of the travel distance measuring system shown in FIG. [Figure 4] FIG. 1 is a diagram for explaining the process from the base material to the second forging in the case of producing a stepped cylindrical material as a forged product. [Figure 5] FIG. 5 is a diagram for explaining the third forging process performed using a travel distance measurement method according to one embodiment of the present invention, following the second forging process shown in FIG. 4, when manufacturing a stepped cylindrical material as a forged product. [Figure 6] FIG. 6 is a diagram for explaining the fourth forging process performed using a travel distance measurement method according to one embodiment of the present invention, following the third forging process shown in FIG. 5, when manufacturing a stepped cylindrical material as a forged product. [Figure 7] FIG. 7 is a diagram for explaining a step of cutting off the end portion on the hanging handle side and the end portion on the fourth shaft side to obtain a forged product after the fourth forging step shown in FIG. 6. [Figure 8] FIG. 5 is a diagram for explaining the third forging process performed using a general travel distance measurement method following the second forging process shown in FIG. 4 when manufacturing a stepped cylindrical material as a forged product. [Figure 9] FIG. 9 is a diagram for explaining a fourth forging step performed in a general manner following the third forging step shown in FIG. 8 when manufacturing a stepped cylindrical material as a forged product. [Figure 10] FIG. 10 is a diagram showing the state of the forged material after the second forging process, the third forging process, and the fourth forging process, for comparing and explaining the case where a stepped cylindrical material is forged using the travel distance measurement method of an example of the present invention with the case where a stepped cylindrical material is forged using the travel distance measurement method of a comparative example. [Figure 11] 10 is a graph showing a comparison of the difference between the actual length and the target length of each portion when a stepped cylindrical material is forged using the travel distance measurement method of an example of the present invention and when a stepped cylindrical material is forged using the travel distance measurement method of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments shown below are examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention is not limited to the following embodiments in terms of the materials, shapes, structures, arrangements, etc. of the components. In addition, the drawings are schematic, and therefore it should be noted that the relationship between thickness and planar dimensions, ratios, etc. may differ from the actual relationship, and the drawings may also contain parts where the relationship and ratio of dimensions differ from each other. FIG. 1 shows a schematic configuration of a forging material travel distance measurement system and a forging device according to one embodiment of the present invention.

[0013] The forging device 1 shown in Figure 1 is used for free forging a forging material 100 such as a cast steel ingot or slab. Here, we will explain the case where the forging material 100 is a stepped cylindrical material that extends slenderly in the longitudinal direction (the direction indicated by xx in Figure 1). The forging device 1 includes a manipulator 2 that grasps one longitudinal end 100a (the right end in Figure 1) of the forging material 100 extending in the longitudinal direction and moves it in the longitudinal direction (the direction indicated by xx in Figure 1), and a forging press 3 that presses down the forging material 100. The manipulator 2 is equipped with a manipulator carriage 21 that travels in a longitudinal direction, i.e., a forward direction toward the forging press 3 and a backward direction away from the forging press 3, and a forging material gripping device 22 rotatably attached to the manipulator carriage 21. The forging material gripping device 22 grips one longitudinal end 100a of the forging material 100 (the right end in FIG. 1).

[0014] The forging press 3 includes a press body 31 mounted on multiple legs 32 extending vertically (indicated by yy in FIG. 1 ). The press body 31 is provided with a ram 33 that moves up and down, and an upper anvil 34 is fixed to the ram 33. A pedestal 36 is provided below and opposite the ram 33, and a lower anvil 35 is fixed to the pedestal 36. An upper tap 37 for circular pour forging is provided on the underside of the upper anvil 34, and a lower tap 38 for circular pour forging is provided on the upper surface of the lower anvil 35. A piston rod 39 for lifting and lowering the upper tap 37 is provided, and a spring 40 is disposed around the piston rod 39 between the lower tap 38 and the upper tap 37 to constantly urge the upper tap 37 upward. A cylindrical forging material 100 is pressed down by the upper tap 37 and the lower tap 38.

[0015] The movement distance measuring system 10 measures the actual movement distance of the forging 100 in the longitudinal direction, and includes a distance meter 12, a movement distance calculation device 13, and a display device 14. The range finder 12 is, for example, a 2D scanner, and is attached to a range finder installation stand 11 provided on the opposite side of the forging press 3 from the manipulator 2 (to the left of the forging press 3 in FIG. 1 ). The range finder 12 measures a distance L1 from the range finder 12 to an end face 100d on the other longitudinal end 100b side (the left end side in FIG. 1 ) of the forging 100, opposite the one longitudinal end 100a side held by the manipulator 2 in the longitudinal direction before the forging 100 moves. The range finder 12 also measures a distance L2 from the range finder 12 to an end face 100d on the other longitudinal end 100b side of the forging 100, opposite the one longitudinal end 100a side held by the manipulator 2 in the longitudinal direction after the forging 100 moves.

[0016] If the installation heights of the forged material 100 and the distance meter 12 are different, the measured distances L1 and L2 must be geometrically corrected accordingly. In addition, the travel distance calculation device 13 and the display device 14 are computer systems with arithmetic processing functions, and each function of the travel distance calculation device 13 and the display device 14 is executed on software in accordance with the instructions of various dedicated computer programs pre-stored in the hardware. The movement distance calculation device 13 calculates the actual movement distance L of the forged material 100 in the longitudinal direction based on the distance L1 and the distance L2 measured by the distance meter 12, using the formula L=L1−L2.

[0017] The display device 14 is configured by, for example, a monitor, and displays the actual movement distance L in the longitudinal direction of the forging 100 calculated by the movement distance calculation device 13 in real time, along with the input target movement distance. FIG. 2 shows an example of the display screen 15 of the display device 14, and the display screen 15 of the display device 14 displays a reset instruction section 16a, an actual movement distance display section 16b, a measurement end instruction section 16c, a target movement distance change input section 16d, and a target movement distance input section 16e. The reset instruction section 16a displays the word "RESET," and when the operator presses the reset instruction section 16a, the reset function is activated, thereby resetting the actual travel distance display section 16b, the target travel distance change input section 16d, the target travel distance input section 16e, and the target travel distance and actual travel distance in the travel distance display graph 17, which will be described later.

[0018] The actual movement distance display section 16b displays the actual movement distance L in the longitudinal direction of the forging material 100 calculated by the movement distance calculation device 13 from the reset position when the worker presses the reset instruction section 16a. In addition, the measurement end instruction section 16c displays the words "measurement end," and when the worker has finished the series of forging operations, he or she presses this measurement end instruction section 16c, and a signal indicating "measurement end" is transmitted to the arithmetic processing device. Furthermore, the target movement distance input section 16e receives and displays the target movement distance from the reset position when the operator presses the reset instruction section 16a.

[0019] Furthermore, when the target travel distance input in the target travel distance input section 16e is changed, the changed target travel distance is input and displayed in the target travel distance change input section 16d. The display screen 15 of the display device 14 also displays a travel distance display graph 17. The travel distance display graph 17 displays the target travel distance from the reset position input in the target travel distance input unit 16e or the target travel distance change input unit 16d. The travel distance display graph 17 also displays in real time the actual travel distance L in the longitudinal direction of the forging 100 calculated by the travel distance calculation device 13 from the reset position displayed in the actual travel distance display unit 16b.

[0020] Next, a process flow of the travel distance measurement system 10, which represents a travel distance measurement method according to one embodiment of the present invention, will be described with reference to FIG. First, in step S1, the range finder 12 measures a distance L1 from the range finder 12 to an end face 100d on the other longitudinal end 100b side of the forged material 100 opposite to the one longitudinal end 100a side held by the manipulator 2 in the longitudinal direction of the forged material 100 before the forged material 100 moves. The range finder 12 also measures a distance L2 from the range finder 12 to an end face 100d on the other longitudinal end 100b side of the forged material 100 opposite to the one longitudinal end 100a side held by the manipulator 2 in the longitudinal direction of the forged material 100 after the forged material 100 moves (distance measurement step).

[0021] That is, when the worker operates the manipulator 2 and an end face 100d on the other longitudinal end 100b side of the forging material 100 opposite to the one longitudinal end 100a side gripped by the manipulator 2 in the longitudinal direction reaches a predetermined position with respect to the forging press 3, the worker presses the reset instruction section 16a on the display screen 15 of the display device 14. Then, the rangefinder 12 measures the distance L1 from the rangefinder 12 to the end face 100d on the other longitudinal end 100b side of the forging material 100 opposite to the one longitudinal end 100a side gripped by the manipulator 2 in the longitudinal direction when the forging material 100 is in this reset position. When the worker operates the manipulator 2 to move the forging material 100 in the longitudinal direction, the range finder 12 constantly measures the distance L2 from the time the forging material 100 is in the reset position to the time after it has been moved, to the end face 100d on the other longitudinal end 100b side of the forging material 100, opposite the one longitudinal end 100a side held by the manipulator 2 in the longitudinal direction.

[0022] Next, in step S2, the movement distance calculation device 13 calculates the actual movement distance L in the longitudinal direction of the forging 100 using the formula L=L1-L2 based on the aforementioned distance L1 and distance L2 measured in step S1 (distance measurement step) (movement distance calculation step). Next, in step S3, the display device 14 displays the actual movement distance L in the longitudinal direction of the forging 100 calculated in step S2 (movement distance calculation step) together with the input target movement distance on the display device in real time (display step). Specifically, the worker inputs the target movement distance from the reset position when the worker presses the reset instruction unit 16a into the target movement distance input unit 16e on the display screen 15 of the display device 14. Then, the display device 14 displays the target movement distance from the reset position indicated by the broken line in FIG. 2 on the movement distance display graph 17 on the display screen 15.

[0023] The display device 14 also displays the actual movement distance L in the longitudinal direction of the forging 100 from the reset position calculated by the movement distance calculation device 13, which is shown by a solid line in Fig. 2, in a movement distance display graph 17 on the display screen 15. The display device 14 also displays the actual movement distance L from the reset position calculated by the movement distance calculation device 13 in an actual movement distance display section 16b on the display screen 15. This completes the processing in the travel distance measurement system 10. Then, when manufacturing the forged product 120 (see FIG. 7), the worker uses this movement distance measuring method to manufacture the forged product 120.

[0024] At this time, the worker refers to the display screen 15 of the display device 14 and determines the longitudinal position of the forging material 100 in the forging press 3 when the actual movement distance L in the longitudinal direction of the forging material 100 becomes the target movement distance as the reduction position, and then reduces the forging material using the forging press 3. Hereinafter, a method for manufacturing a forged product will be specifically described with reference to FIGS. 4 to 7, taking as an example a case where a stepped cylindrical material is manufactured as the forged product 120. As shown in FIG. 7, the forged product 120 to be manufactured is a stepped cylindrical material having a trunk portion 110, a first shaft portion 104, a second shaft portion 109, a hanging handle portion 107, a third shaft portion 112, and a fourth shaft portion 113. The trunk portion 110 extends in the longitudinal direction, and the first shaft portion 104 is provided adjacent to the trunk portion 110 on the other longitudinal end 100b side (the right end side in FIG. 7). The second shaft portion 109 is provided adjacent to the first shaft portion 104 on the other longitudinal end 100b side. The hanging handle portion 107 is provided adjacent to the second shaft portion 109 on the other longitudinal end 100b side. The third shaft portion 112 is provided adjacent to the trunk portion 110 on the one longitudinal end 100a side (the left end side in FIG. 7). The fourth shaft portion 113 is located adjacent to the third shaft portion 112 on the longitudinal end 100a side. The diameters of the first shaft portion 104, the hanging handle portion 107, and the third shaft portion 112 are the same and are smaller than the diameter of the body portion 110. The diameter of the second shaft portion 109 is smaller than the diameters of the first shaft portion 104 and the hanging handle portion 107. The diameter of the fourth shaft portion 113 is smaller than the diameter of the third shaft portion 112.

[0025] FIG. 4 shows the steps from the base material to the second forging in the case of producing a stepped cylindrical material as a forged product 120. First, as shown in Fig. 4(a), the worker grips one longitudinal end 100a of the cast forging (base material) 100 with the forging gripping device 22 of the manipulator 2. Then, the worker moves the manipulator carriage 21 until the other longitudinal end 100b of the forging 100 is positioned near the upper anvil 34 and the lower anvil 35 of the forging press 3. The cast forging (base material) 100 has a cylindrical shape and a diameter d1. Next, as shown in Figure 4(b), the worker performs a first forging of the forging material 100, forming a portion 101 to form a trunk portion at the other longitudinal end 100b and a portion 102 to form a shaft portion at one longitudinal end 100a. The diameter d2 of the portion 101 to form a trunk portion is made smaller than the diameter d1 of the base material. During the first forging, the forging material 100 is gripped at one longitudinal end 100a by the forging material gripping device 22 of the manipulator 2 and moved longitudinally relative to the forging press 3 while rotating the forging material 100, and the forging material 100 is reduced by the upper tap 37 and the lower tap 38.

[0026] Next, the worker reheats the forging material 100 and then performs a second forging on the forging material 100 as shown in Figure 4(c), thereby finishing the diameter of the portion 101 intended to form the body portion to a diameter d3 of the body portion 110 that is smaller than d2. During the second forging, the forging material 100 is again gripped by the forging material gripping device 22 of the manipulator 2 at one longitudinal end 100a and moved longitudinally relative to the forging press 3 while rotating the forging material 100, and the forging material 100 is reduced by the upper tap 37 and the lower tap 38. Next, the worker heats the forged material 100 again and then performs a third forging on the forged material 100 as shown in FIGS. 5(a) to 5(e).

[0027] In the third forging, first, the worker applies marking A at a position a predetermined target distance away from the end face 101a on the longitudinal end 100a side of the portion 101 intended to form the body portion toward the other longitudinal end 100b side, as shown in Figure 5(a). Then, the worker measures the distance in the longitudinal direction from the end face 101a on the side of one longitudinal end 100a of the portion 101 to be formed into the trunk portion to the marking A using the movement distance measuring system 10 (movement distance measuring method). That is, the worker grips one longitudinal end 100a of the forging material 100 with the forging material gripping device 22 of the manipulator 2 and moves the forging material 100 so that the end face 101a of the longitudinal end 100a of the portion 101 to form the trunk portion coincides with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. Then, the worker presses the reset instruction section 16a on the display screen 15 of the display device 14. This activates the reset function of the display device 14, and the reset position is changed.

[0028] Next, the operator inputs a target travel distance into the target travel distance input unit 16e on the display screen 15 of the display device 14. The target travel distance here is the same as the target distance when applying the marking A described above. The target travel distance input into the target travel distance input unit 16e is displayed on the travel distance display graph 17 on the display screen 15 of the display device 14 (see FIG. 2). When this reset position is identified, the rangefinder 12 measures the distance from the rangefinder 12 to the end face 100d on the other longitudinal end 100b opposite to the one longitudinal end 100a of the forged material 100 grasped by the manipulator 2 in the longitudinal direction. This distance is the distance L1 from the rangefinder 12 to the end face 100d on the other longitudinal end 100b opposite to the one longitudinal end 100a of the forged material 100 grasped by the manipulator 2 in the longitudinal direction before the forged material 100 is moved.

[0029] The worker then retracts the manipulator 2 in the direction indicated by the arrow in Figure 5(a) to retract the forging 100. At this time, the range finder 12 measures the distance from the range finder 12 to the end face 100d on the other longitudinal end 100b side of the forging 100, opposite the one longitudinal end 100a side held by the manipulator 2 in the longitudinal direction. This distance is the distance L2 from the range finder 12 to the end face 100d on the other longitudinal end 100b side of the forging 100, opposite the one longitudinal end 100a side held by the manipulator 2 in the longitudinal direction after the forging 100 has moved from the reset position. Here, the movement distance calculation device 13 calculates the actual movement distance L in the longitudinal direction of the forging material 100 using the formula L=L1-L2 based on the aforementioned distance L1 measured by the rangefinder 12 before the forging material 100 moves from the rangefinder 12 (when it is in the reset position) and the aforementioned distance L2 after the forging material 100 moves from the rangefinder 12 (after it moves from the reset position).

[0030] The display device 14 then displays the actual movement distance L from the reset position in the longitudinal direction of the forging 100 calculated by the movement distance calculation device 13, along with the input target movement distance, in real time. In other words, the movement distance display graph 17 on the display screen 15 of the display device 14 displays the target movement distance inputted into the target movement distance input section 16e and the actual movement distance L from the reset position in the longitudinal direction of the forging material 100 calculated by the movement distance calculation device 13. Then, the worker refers to the display screen 15 of the display device 14 and when the actual movement distance L from the reset position in the longitudinal direction of the forging material 100 reaches the target movement distance, the worker finishes measuring the longitudinal distance from the end face 101a on the longitudinal end 100a side of the portion 101 intended to form the body portion to the marking A.

[0031] The worker then determines the longitudinal position of the forging 100 in the forging press 3 when the actual longitudinal movement distance L of the forging 100 from the reset position becomes the target movement distance as the reduction position. At this reduction position, the worker then uses the upper tap 37 and the lower tap 38 to reduce the portion of the portion 101 intended to form the body portion from marking A to the other longitudinal end (the portion to the left of marking A in FIG. 5(a)). The worker also operates the manipulator 2 to move the forging 100 backward while using the upper tap 37 and the lower tap 38 to reduce the remaining portion of the portion 101 intended to form the body portion. 5(b), a first shaft portion 103 is formed adjacent to the other longitudinal end of the body portion 101. The diameter of the first shaft portion 103 is smaller than the diameter d3 of the body portion 101.

[0032] Next, as shown in Figure 5(b), the worker applies marking B to the first shaft portion-forming portion 103 at a position a predetermined target distance away from the end face 101b on the other longitudinal end 100b side of the body portion-forming portion 101 toward the other longitudinal end 100b. The worker also applies marking C to the portion 103 where the first shaft portion is to be formed, at a position a predetermined target distance away from the end face 100d on the other longitudinal end 100b side of the portion 103 where the first shaft portion is to be formed, toward the one longitudinal end 100a side. 5(c), the worker grips one longitudinal end 100a of the forging 100 with the forging gripping device 22 and moves the forging 100 so that the end face 101b on the other longitudinal end 100b of the portion 101 to form the trunk portion coincides with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. Then, using the same technique as described above, the worker measures the longitudinal distance from the end face 101b on the other longitudinal end 100b of the portion 101 to form the trunk portion in the portion 103 to be formed the first shaft portion, to the marking B, using the travel distance measuring system 10 (travel distance measuring method).

[0033] Then, referring to the display screen 15 of the display device 14, the worker determines the longitudinal position of the forging 100 in the forging press 3 when the actual movement distance L from the reset position in the longitudinal direction of the forging 100 reaches the target movement distance (the same as the target distance of marking B) as the reduction position. Here, the reset position is a position where the end face 101b on the other longitudinal end 100b side of the portion 101 to form the trunk portion coincides with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. Then, at this pressing position, the operator uses the upper tap 37 and the lower tap 38 to press down the portion 103 intended to form the first shaft portion by the press width from marking B (the portion to the left of marking B in FIG. 5(c)). This forms a first shaft portion 104 adjacent to the portion 101 intended to form the body portion, a first pressing down shaft portion 105 of the press width adjacent to the first shaft portion 104, and a remaining portion 106 adjacent to the first pressing down shaft portion 105. The diameter of the first shaft portion 104 is the same as that of the portion 103 intended to form the first shaft portion but is smaller than the diameter of the portion 101 intended to form the body portion, and the diameter of the first pressing down shaft portion 105 is smaller than the diameters of the first shaft portion 104 and the remaining portion 106.

[0034] 5(d), the worker grips one longitudinal end 100a of the forging 100 with the forging gripping device 22 and moves the forging 100 so that the end face 100d of the other longitudinal end 100b of the remaining portion 106 coincides with the other end face 37b of the upper tap 37 and the other end face 38b of the lower tap 38. Then, using the same technique as described above, the worker measures the longitudinal distance from the end face 100d of the other longitudinal end 100b of the remaining portion 106 to the marking C using the travel distance measuring system 10 (travel distance measuring method). Then, referring to the display screen 15 of the display device 14, the worker determines the longitudinal position of the forging 100 in the forging press 3 when the actual movement distance L from the reset position in the longitudinal direction of the forging 100 reaches the target movement distance (the same as the target distance of the marking C) as the reduction position. Here, the reset position is a position where the end face 100d on the other longitudinal end 100b side of the remaining portion 106 coincides with the other end face 37b of the upper tap 37 and the other end face 38b of the lower tap 38. Then, at this pressing position, the worker uses the upper tap 37 and the lower tap 38 to press down the remaining portion 106 from marking C by the press width (the portion to the right of marking C in Figure 5 (d)). This forms a hanging handle portion 107 and a second rolling down shaft portion 108 of the press width adjacent to the hanging handle portion 107. The diameter of the hanging handle portion 107 is the same as the diameters of the remaining portion 106 and the first shaft portion 104, and the diameter of the second rolling down shaft portion 108 is smaller than the diameter of the hanging handle portion 107.

[0035] Next, as shown in Figure 5(e), the worker uses the upper tap 37 and the lower tap 38 to move the forged material 100 forward and backward as indicated by the arrows, thereby pressing down the area between the end face 107a on the longitudinal end 100a side of the hanging handle portion 107 and the end face 104a on the longitudinal other end 100b side of the first shaft portion 104. This forms a second shaft portion 109 between the first shaft portion 104 and the hanging handle portion 107. The diameter of the second shaft portion 109 is smaller than the diameters of the first shaft portion 104 and the hanging handle portion 107. Next, the worker heats the forged material 100 again and then performs a fourth forging on the forged material 100 as shown in FIGS. 6(a) to 6(c).

[0036] In the fourth forging, first, as shown in Figure 6(a), the worker applies marking D to the portion 101 intended to form the trunk portion at a position that is a predetermined target distance away from the end face 101b on the other longitudinal end 100b side of the portion 101 intended to form the trunk portion toward the one longitudinal end 100a. 6(a), the worker grips the hanging handle portion 107 on the other longitudinal end 100b side of the forging 100 with the forging gripping device 22 and moves the forging 100 so that the end face 101b on the other longitudinal end 100b side of the portion 101 to form the body portion coincides with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. Then, using the same technique as described above, the worker measures the longitudinal distance from the end face 101b on the other longitudinal end 100b side of the portion 101 to the marking D in the portion 101 to form the body portion using the travel distance measuring system 10 (travel distance measuring method).

[0037] When measuring this distance, the range finder 12 measures the distance L1 from the range finder 12 to the end face 100c on the side of one longitudinal end 100a of the forging 100 before the forging 100 moves. Here, "before the forging 100 moves" means when it is in the reset position, that is, when the end face 101b on the side of the other longitudinal end 100b of the portion 101 to form the trunk portion coincides with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. The range finder 12 also measures the distance L2 from the range finder 12 to the end face 100c on the side of one longitudinal end 100a of the forging 100 after the forging 100 has moved (after moving from the reset position). Further, based on the distances L1 and L2 measured by the distance meter 12, the movement distance calculation device 13 calculates the actual movement distance L of the forging 100 in the longitudinal direction by the formula L=L1−L2.

[0038] The display device 14 also displays the actual movement distance L from the reset position in the longitudinal direction of the forging 100 calculated by the movement distance calculation device 13 in real time, along with the input target movement distance (target distance of the marking D). Then, referring to the display screen 15 of the display device 14, the worker determines the longitudinal position of the forging 100 in the forging press 3 when the actual movement distance L from the reset position in the longitudinal direction of the forging 100 reaches the target movement distance (the same as the target distance of the marking D) as the reduction position. Here, the reset position is a position where the end face 101b on the other longitudinal end 100b side of the portion 101 to form the trunk portion coincides with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. Then, at this reduction position, the worker uses the upper tap 37 and the lower tap 38 to reduce the portion 101 to form the trunk portion, from marking D to one longitudinal end 100a (the portion to the left of marking D in Figure 6(a)). He also operates the manipulator 2 to move the forging material 100 backward in the direction of the arrow, while using the upper tap 37 and the lower tap 38 to reduce the portion 102 to form the shaft portion. This forms a trunk portion 110 and a portion 111 to form a third shaft portion adjacent to one longitudinal end of the trunk portion 110, as shown in Figure 6(b). The diameter of the portion 111 to form the third shaft portion is the same as the diameter of the first shaft portion 104 and is smaller than the diameter of the trunk portion 110.

[0039] Next, as shown in Figure 6(b), the worker makes a marking E in the portion 111 where the third shaft portion is to be formed, at a position a predetermined target distance away from the end face 110c on the longitudinal end 100a side of the body portion 110 toward the longitudinal end 100a side. 6(b), the worker grips the hanger portion 107 on the other longitudinal end 100b side of the forging 100 with the forging gripping device 22 and moves the forging 100 so that the end face 110c on one longitudinal end 100a side of the trunk portion 110 is aligned with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. Then, using the same technique as described above, the worker measures the longitudinal distance from the end face 110c on one longitudinal end 100a side of the trunk portion 110 to the marking E in the portion 111 to form the third shaft portion using the travel distance measuring system 10 (travel distance measuring method).

[0040] Then, referring to the display screen 15 of the display device 14, the worker determines the longitudinal position of the forging 100 in the forging press 3 when the actual movement distance L from the reset position in the longitudinal direction of the forging 100 reaches the target movement distance (the same as the target distance of the marking E) as the reduction position. Here, the reset position is a position where the end face 110c on the longitudinal end 100a side of the trunk portion 110 coincides with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. Then, at this reduction position, the worker uses the upper tap 37 and the lower tap 38 to reduce the portion 111 scheduled to form the third shaft portion from the marking E to one longitudinal end 100a (the portion to the left of the marking E in Figure 6(b)). He also operates the manipulator 2 to move the forging material 100 backward in the direction of the arrow while reducing the remainder of the portion 111 scheduled to form the third shaft portion. This forms a third shaft portion 112 adjacent to one longitudinal end of the trunk portion 110, and a fourth shaft portion 113 adjacent to one longitudinal end of the third shaft portion 112, as shown in Figure 6(c). The diameter of the third shaft portion 112 is the same as the diameter of the portion 111 scheduled to form the third shaft portion, and the diameter of the fourth shaft portion 113 is smaller than the diameter of the third shaft portion 112.

[0041] This completes the forging process for the forged material 100. After the forging process of the forged material 100 is completed, the worker cuts off the end 107b on the hanging handle portion 107 side and the end 113a on the fourth shaft portion 113 side, as shown in FIG. The cutting is performed so that the overall length L120 of the forged product 120 after cutting and the length L107 of the hanging handle portion 107 are the specified dimensions. If the length L110 of the body portion 110 and the total length L120 of the forged product 120 are within the specified range, the forged product 120 passes the test.

[0042] As described above, according to the forging movement distance measurement system 10 and movement distance measurement method of this embodiment, the rangefinder 12 (distance measurement step: step S1) measures a distance L1 from the rangefinder 12 to the end face 100d on the other longitudinal end 100b side opposite to the one longitudinal end 100a side gripped by the manipulator 2 in the longitudinal direction (xx direction) of the forging 100 before the forging 100 moves. Also, the rangefinder 12 (distance measurement step: step S1) measures a distance L2 from the rangefinder 12 to the end face 100d on the other longitudinal end 100b side opposite to the one longitudinal end 100a side gripped by the manipulator 2 in the longitudinal direction (xx direction) of the forging 100 after the forging 100 moves. In addition, the movement distance calculation device 13 (movement distance calculation step: step S2) calculates the actual movement distance L in the longitudinal direction (xx direction) of the forging 100 based on the aforementioned distance L1 and distance L2 measured by the rangefinder 12 (distance measurement step: step S1).

[0043] As a result, the travel distance of the forging 100 can be obtained directly from the forging 100, thereby improving the accuracy of measuring the travel distance of the forging 100. Even if the forging 100 moves when the forging press 3 reduces the forging 100, the travel distance of the forging 100 can be obtained directly from the forging 100. Therefore, the travel distance of the forging 100 can be measured with high accuracy. When the forging press 3 reduces the forging 100, the forging 100 moves, for example, when the forging gripping device 22 of the manipulator 2 moves slightly due to the impact of the reduction, or when the wheel portion of the manipulator carriage 21 moves slightly due to the impact of the reduction. Furthermore, according to the forging material movement distance measuring system 10 and movement distance measuring method of this embodiment, the display device 14 (display step: step S3) displays in real time the actual movement distance L in the longitudinal direction (xx direction) of the forging material 100 calculated by the movement distance calculation device 13 (movement distance calculation step: step S2) together with the input target movement distance.

[0044] This allows the worker to refer to the display device 14 and understand the actual movement distance of the forging 100 by comparing it with the target movement distance. Furthermore, according to the method for manufacturing a forged product according to this embodiment, the above-described movement distance measurement method is used to manufacture the forged product 120. This makes it possible to improve the accuracy of distance measurement in the forged material when manufacturing the forged product 120, and to improve the dimensional accuracy of the forged product 120. Furthermore, according to the manufacturing method of the forged product of this embodiment, the longitudinal position of the forged material 100 in the forging press 3 when the actual movement distance L in the longitudinal direction (xx direction) of the forged material 100 becomes the target movement distance is determined as the reduction position by referring to the display device 14, and the forged material 100 is reduced by the forging press 3.

[0045] This allows the reduction position of the forging material 100 in the forging press 3 to be determined with high precision, and the dimensional precision of the forged product 120 to be further improved. Next, a method for manufacturing a forged product using a general travel distance measurement method will be described with reference to Figs. 8 and 9, in contrast to the method for manufacturing a forged product 120 using the travel distance measurement system 10 (travel distance measurement method). Fig. 8 is a diagram for explaining a third forging process performed using a general travel distance measurement method following the second forging process shown in Fig. 4 when manufacturing a stepped cylindrical material as a forged product. Fig. 9 is a diagram for explaining a fourth forging process performed using a general method following the third forging process shown in Fig. 8 when manufacturing a stepped cylindrical material as a forged product.

[0046] When manufacturing the forged product 120 using a general movement distance measurement method, the process from the base material to the second forging is the same as the method shown in FIG. Then, when performing the third forging on the forged material 100, the worker heats the forged material 100 and then performs the third forging on the forged material 100 through the steps shown in Figures 8(a) to 8(c). In the third forging, first, the worker applies marking A at a position a predetermined target distance away from the end face 101a on the longitudinal end 100a side of the portion 101 intended to form the body portion toward the other longitudinal end 100b side, as shown in Figure 8(a).

[0047] The worker then measures the longitudinal distance from end face 101a on one longitudinal end 100a of portion 101 to form the trunk portion. The worker grips the longitudinal end 100a of forging 100 with forging gripping device 22 and moves forging 100 so that end face 101a on one longitudinal end 100a of portion 101 to form the trunk portion coincides with one end face 37a of upper tap 37 and one end face 38a of lower tap 38. The worker then moves forging 100 backward, as indicated by the arrow, and moves forging 100 so that marking A on portion 101 to form the trunk portion coincides with one end face 37a of upper tap 37 and one end face 38a of lower tap 38.

[0048] The worker then determines the position where marking A coincides with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38 as the reduction position. At this reduction position, the upper tap 37 and the lower tap 38 are used to reduce the portion of the portion 101 to form the trunk portion, from marking A to the other end in the longitudinal direction (the portion to the left of marking A in Figure 8(a)). Furthermore, the manipulator 2 is operated to move the forging material 100 backward, while the upper tap 37 and the lower tap 38 are used to reduce the remaining portion of the portion 101 to form the trunk portion. 8(b), a first shaft portion 103 is formed adjacent to the other longitudinal end of the body portion 101. The diameter of the first shaft portion 103 is smaller than the diameter of the body portion 101.

[0049] Next, as shown in Figure 8(b), the worker applies marking B to the first shaft portion-forming portion 103 at a position a predetermined target distance away from the end face 101b on the other longitudinal end 100b side of the body portion-forming portion 101 toward the other longitudinal end 100b. The worker also applies marking C to the portion 103 where the first shaft portion is to be formed, at a position a predetermined target distance away from the end face 100d on the other longitudinal end 100b side of the portion 103 where the first shaft portion is to be formed, toward the one longitudinal end 100a side. 8(b), the worker measures the distance from the end face 100d on the other longitudinal end 100b side of the portion 103 to form the first shaft portion to the marking B. At this time, the worker holds the one longitudinal end 100a side of the forging 100 with the forging gripping device 22 and moves the forging 100 so that the end face 101b on the other longitudinal end 100b side of the portion 101 to form the trunk portion is aligned with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38.

[0050] Next, as shown in Figure 8(c), the worker moves the forging material 100 backward as indicated by the arrow. The worker moves the forging material 100 so that the marking B formed on the portion 103 to be formed as the first shaft portion is visually aligned with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. This position is then designated as the reduction position. Then, as shown in Figure 8(c), the worker uses the upper tap 37 and the lower tap 38 at this reduction position to reduce the portion of the portion 103 intended to form the first shaft portion from marking B to the other end in the longitudinal direction (the portion to the left of marking B in Figure 8(c)).Furthermore, while operating the manipulator 2 to move the forging material 100 backward, the worker uses the upper tap 37 and the lower tap 38 to visually reduce the portion of the portion 103 intended to form the first shaft portion between marking B and marking C in the direction from marking B to marking C as indicated by the arrow in Figure 8(c). This forms a first shaft portion 104 adjacent to the other longitudinal end of the portion 101 intended to form a body portion, a second shaft portion 109 adjacent to the other longitudinal end of the first shaft portion 104, and a hanger portion 107 adjacent to the other longitudinal end of the second shaft portion 109. The diameter of the first shaft portion 104 is the same as the diameter of the portion 103 intended to form a first shaft portion and is smaller than the diameter of the portion 101 intended to form a body portion. The diameter of the second shaft portion 109 is also smaller than the diameter of the first shaft portion 104. Furthermore, the diameter of the hanger portion 107 is the same as the diameter of the first shaft portion 104.

[0051] Next, the worker heats the forged material 100 again and then performs a fourth forging on the forged material 100 as shown in FIGS. 9(a) to 9(c). In the fourth forging, first, as shown in Figure 9(a), the worker applies marking D to the portion 101 intended to form the trunk portion at a position that is a predetermined target distance away from the end face 101b on the other longitudinal end 100b side of the portion 101 intended to form the trunk portion toward the one longitudinal end 100a. 9(a), the worker measures the distance from the end face 101b on the other longitudinal end 100b side of the portion 101 to form the trunk portion to the marking D. At this time, the worker grips the hanging handle portion 107 on the other longitudinal end 100b side of the forging 100 with the forging gripping device 22 and moves the forging 100 so that the end face 101b on the other longitudinal end 100b side of the portion 101 to form the trunk portion is aligned with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38.

[0052] Next, as shown in Figure 9(a), the worker moves the forging material 100 backward as indicated by the arrow. The worker moves the forging material 100 so that the marking D on the portion 101 to form the trunk portion is visually aligned with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. This position is then designated as the reduction position. Then, at this reduction position, the worker uses the upper tap 37 and the lower tap 38 to reduce the portion 101 to form the trunk portion, from marking D to one longitudinal end 100a (the portion to the left of marking D in Figure 9(a)). Furthermore, by operating the manipulator 2, the forging material 100 is moved backward in the direction of the arrow while the upper tap 37 and the lower tap 38 reduce the portion 102 to form the shaft portion. This forms a trunk portion 110 and a portion 111 to form a third shaft portion adjacent to one longitudinal end of the trunk portion 110, as shown in Figure 9(b). The diameter of the portion 111 to form the third shaft portion is the same as the diameter of the first shaft portion 104 and is smaller than the diameter of the trunk portion 110.

[0053] Next, as shown in Figure 9(b), the worker makes a marking E in the third shaft portion formation portion 111 at a position a predetermined target distance away from the end face 110c on the longitudinal end 100a side of the body portion 110 toward the longitudinal end 100a side. 9(b), the worker measures the distance from the end face 110c on the longitudinal end 100a side of the trunk portion 110 to the marking E in the portion 111 where the third shaft portion will be formed. At this time, the worker grips the hanging handle portion 107 on the other longitudinal end 100b side of the forging 100 with the forging gripping device 22 and moves the forging 100 so that the end face 110c on the longitudinal end 100a side of the trunk portion 110 is aligned with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38.

[0054] Next, the worker moves the forging material 100 backward as indicated by the arrow. The worker moves the forging material 100 so that the marking E on the portion 111 to be used to form the third shaft portion is visually aligned with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. This position is then designated as the reduction position. Then, at this reduction position, the operator uses the upper tap 37 and the lower tap 38 to reduce the portion 111 scheduled to form the third shaft portion from the marking E toward one longitudinal end 100a (the portion to the left of the marking E in Figure 9(b)). Furthermore, by operating the manipulator 2, the forging material 100 is moved backward in the direction of the arrow while the upper tap 37 and the lower tap 38 reduce the remaining portion of the portion 111 scheduled to form the third shaft portion. As a result, as shown in Figure 9(c), a third shaft portion 112 adjacent to one longitudinal end of the trunk portion 110 and a fourth shaft portion 113 adjacent to one longitudinal end of the third shaft portion 112 are formed. The diameter of the third shaft portion 112 is the same as the diameter of the portion 111 scheduled to form the third shaft portion, and the diameter of the fourth shaft portion 113 is smaller than the diameter of the third shaft portion 112.

[0055] This completes the forging process for the forged material 100. After the forging process of the forging material 100 is completed, the worker cuts off the end 107b on the hanging handle portion 107 side and the end 113a on the fourth shaft portion 113 side, as shown in Figure 7, to complete the forged product 120. The end 107b on the hanging handle portion 107 side and the end 113a on the fourth shaft portion 113 side are cut so that the overall length L120 of the forged product 120 after cutting and the length L107 of the hanging handle portion 107 are the specified dimensions. If the length L110 of the body portion 110 and the total length L120 of the forged product 120 are within the specified range, the forged product 120 passes the test.

[0056] In a method for manufacturing a forged product using this general method for measuring the distance traveled, the longitudinal distance from the end face 101a at one longitudinal end 100a of the portion 101 to form the trunk portion is measured as follows: The forging 100 is gripped at one longitudinal end 100a with the forging gripping device 22, and the forging 100 is moved so that the end face 101a at the one longitudinal end 100a of the portion 101 to form the trunk portion coincides with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38. The forging 100 is then retracted, and the forging 100 is moved so that the marking A on the portion 101 to form the trunk portion coincides with one end face 37a of the upper tap 37 and one end face 38a of the lower tap 38, as visually observed. Similarly, when measuring the distance from the end face 100d on the other longitudinal end 100b side of the portion 103 to form the first shaft portion to the marking B, the forged material 100 is moved visually. Similarly, when measuring the distance from the end face 101b on the other longitudinal end 100b side of the portion 101 to form the trunk portion to the marking D, the forged material 100 is moved visually. Furthermore, when measuring the distance from the end face 110c on the one longitudinal end 100a side of the trunk portion 110 on the portion 111 to form the third shaft portion to the marking E, the forged material 100 is moved visually.

[0057] The accuracy of the distance measurement to such markings A, B, D, and E is determined by visual inspection by the operator, and therefore the accuracy of the distance measurement is lower than when distance measurement is performed using the travel distance measurement system 10 (travel distance measurement method) of this embodiment. Thus, when an operator visually measures the distance, the length L110 of the trunk portion 110 in the forged product 120 tends to be large. This is because the operator forges the trunk portion 110 so that the length L110 is large to be on the safe side. As a result, the length L107 of the product end 107 on the hanging handle portion 107 side and the length L113 of the product end 113 on the fourth shaft portion 113 side may not meet the required length. This increases the risk that the forged product 120 will be rejected.

[0058] In contrast, when a forged product is manufactured using the movement distance measurement method according to this embodiment, as described above, the range finder 12 (distance measurement step: step S1) measures the distance L1 from the range finder 12 to the end face 100d on the other longitudinal end 100b side opposite to the one longitudinal end 100a side held by the manipulator 2 in the longitudinal direction (xx direction) of the forged material 100 before the forged material 100 moves. In addition, the range finder 12 measures the distance L2 from the range finder 12 to the end face 100d on the other longitudinal end 100b side opposite to the one longitudinal end 100a side held by the manipulator 2 in the longitudinal direction (xx direction) of the forged material 100 after the forged material 100 moves. In addition, the movement distance calculation device 13 (movement distance calculation step: step S2) calculates the actual movement distance L in the longitudinal direction (xx direction) of the forging 100 based on the aforementioned distance L1 and distance L2 measured by the rangefinder 12 (distance measurement step: step S1).

[0059] This improves the accuracy of measuring the distance traveled by the forged material 100 by directly obtaining the distance traveled by the forged material 100. This ensures that the length L107 of the product end 107 on the hanging handle portion 107 side and the length L113 of the product end 113 on the fourth shaft portion 113 side are equal to or greater than the required lengths, reducing the risk that the forged product 120 will be rejected. Furthermore, when manufacturing a forged product using this general method of measuring travel distance, as shown in Figure 8(c), the upper tap 37 and the lower tap 38 are used to press down the portion of the portion 103 to form the first shaft portion from marking B to the other longitudinal end (the portion to the left of marking B in Figure 8(c)). Furthermore, the manipulator 2 is operated to move the forging material 100 backward, while the upper tap 37 and the lower tap 38 are used to visually press down the portion 103 to form the first shaft portion between marking B and marking C in the direction from marking B to marking C as indicated by the arrow in Figure 8(c). This forms a first shaft portion 104 adjacent to the other longitudinal end of the portion 101 to form the trunk portion, a second shaft portion 109 adjacent to the other longitudinal end of the first shaft portion 104, and a hanging handle portion 107 adjacent to the other longitudinal end of the second shaft portion 109.

[0060] Here, the portion between marking B and marking C of the portion 103 to be formed as the first axis portion is pressed down in the direction from marking B to marking C as shown by the arrow in Figure 8(c). As a result, the portion 103 to be formed as the first axis portion between marking B and marking C stretches in the longitudinal direction, so the longitudinal movement distance of the manipulator 2 is not equal to the actual movement distance of the forged material 100. If this method is applied to the manufacturing method of the forged product according to this embodiment, the same problem will occur. For this reason, in the manufacturing method of a forged product according to this embodiment, as shown in Figures 5(c) to 5(e), a first shaft portion 104 with a predetermined length is formed in a portion 103 where the first shaft portion is to be formed. Then, a hanging handle portion 107 with a similarly predetermined length is formed, and then the portion between the first shaft portion 104 and the hanging handle portion 107 is pressed down to form a second shaft portion 109. This makes it possible to apply the movement distance measurement method of this embodiment regardless of the elongation of the material.

[0061] Although the embodiment of the present invention has been described above, the present invention is not limited to this and various modifications and improvements can be made. For example, the forged product 120 and the forged material 100 are not limited to stepped cylindrical materials, but may also be rectangular or prismatic, such as a slab. Furthermore, the forged material 100 is not limited to being elongated in the longitudinal direction (xx direction), but may be one whose height in the up-down direction (yy direction) is greater than its length in the longitudinal direction (xx direction). [Example]

[0062] A stepped cylindrical material as the forged material 100 shown in Fig. 10 was forged by an example of the present invention using a forging process similar to the forging process shown in Figs. 4 to 6. The above-mentioned stepped cylindrical material was also forged by a comparative example using a forging process similar to the forging process shown in Figs. 8 and 9. Then, for the example of the present invention and the comparative example, the differences between the actual lengths and the target lengths of the length a of the first shaft portion 104, the length b of the second shaft portion 109, the length c of the hanging handle portion 107, the length d of the body portion 110, and the length e of the third shaft portion 112 shown in Fig. 10 were evaluated. The evaluation results are shown in Figure 11. As shown in Figure 11, the average difference between the actual and target lengths of the first shaft portion 104 (length a), the second shaft portion 109 (length b), the hanger portion 107 (length c), the trunk portion 110 (length d), and the third shaft portion 112 (length e) of the stepped cylindrical material forged according to the present invention was approximately 67 mm. In contrast, the average difference between the actual and target lengths of the first shaft portion 104 (length a), the second shaft portion 109 (length b), the hanger portion 107 (length c), the trunk portion 110 (length d), and the third shaft portion 112 (length e) of the stepped cylindrical material forged according to the comparative example was approximately 83 mm. Therefore, the average difference was approximately 16 mm smaller for the present invention example than for the comparative example. Furthermore, the standard deviation σ was 26 mm smaller for the present invention example than for the comparative example.

[0063] The reason for this is that when forging a stepped cylindrical material according to the present invention, the length a of the first shaft portion 104, the length c of the hand strap portion 107, the length d of the trunk portion 110, and the length e of the third shaft portion 112 are measured using a travel distance measurement system 10 (travel distance measurement method). The length b of the second shaft portion 109 was calculated by subtracting the length a of the first shaft portion 104 and the length c of the hand strap portion 107 from the distance between the end face 101b (see FIG. 5(e)) on the other longitudinal end 100b side of the portion 101 to form the trunk portion and the end face 100d on the other longitudinal end 100b side of the hanging strap portion 107. In contrast, in the comparative example, the length a of the first shaft portion 104, the length d of the body portion 110, and the length e of the third shaft portion 112 were measured visually. The length b of the second shaft portion 109 was measured visually after the second shaft portion 109 had been formed to a certain extent, and the length was adjusted. The length c of the hanging handle portion 107 was not measured.

[0064] Thus, the average and standard deviation σ of the difference between the actual length and the target length are smaller in the invention example than in the comparative example, which is presumably the result of improved measurement accuracy in the invention example compared to the comparative example. [Explanation of symbols]

[0065] 1 Forging equipment 2 Manipulator 3 Forging press 10. Travel distance measurement system 11 Distance meter installation stand 12 Rangefinder 13 Travel distance calculation device 14 Display device 15 Display screen 16a Reset instruction section 16b Actual travel distance display section 16c Measurement end instruction section 16d Target movement distance change input section 16e Target travel distance input section 17 Travel distance display graph 21 Manipulator cart 22 Forging gripping device 31 Press machine body 32 Legs 33 Ram 34 Upper anvil 35 Lower anvil 36 Pedestal 37 Up tap 38 Down Tap 39 Piston rod 40 Spring 100 Forged material 100a Longitudinal end 100b Other longitudinal end 100c End face on one end in the longitudinal direction 100d End face on the other end in the longitudinal direction 101 Torso formation part 102 Shaft formation planned part 103 First axis section planned to be formed 104 1st axis part 105 1st rolling shaft part 106 Remaining part 107 Hanging handle 108 2nd rolling shaft part 109 2nd axis part 110 Torso 111 Third axis section planned to be formed 112 3rd axis part 113 4th axis part L Actual travel distance L1 Distance before movement L2 Distance after movement

Claims

1. A forging material movement distance measurement system for use in a forging device including a manipulator that grips one end of a forging material in a longitudinal direction and moves the forging material in the longitudinal direction, and a forging press that presses the forging material in a direction perpendicular to the longitudinal direction, a range finder that measures the distance from the range finder to an end face of the other longitudinal end of the forged material opposite to the one longitudinal end held by the manipulator before the forged material is moved by the manipulator, and the distance from the range finder to an end face of the other longitudinal end of the forged material opposite to the one longitudinal end held by the manipulator after the forged material is moved by the manipulator; a movement distance calculation device that calculates an actual movement distance of the forged material in the longitudinal direction by the manipulator based on the distance measured by the distance meter from the distance meter to the end face on the other longitudinal end side of the forged material before the forged material moves and the distance measured by the distance meter from the distance meter to the end face on the other longitudinal end side of the forged material after the forged material moves, a display device that displays in real time the input target movement distance and the actual movement distance in the longitudinal direction of the forging calculated by the movement distance calculation device; The display screen of the display device includes an actual travel distance display unit that displays the actual travel distance in the longitudinal direction of the forged material calculated by the travel distance calculation device, a target travel distance input unit that inputs and displays a target travel distance, a target travel distance change input unit that inputs and displays the changed target travel distance when the target travel distance input in the target travel distance input unit is changed, and a travel distance display graph that displays the target travel distance input in the target travel distance input unit or the changed target travel distance input in the target travel distance change input unit, and also displays the actual travel distance in the longitudinal direction of the forged material displayed in the actual travel distance display unit in real time.

2. A method for measuring a moving distance of a forged material when a forged product is manufactured using a forging device including a manipulator that grips one end of the forged material in the longitudinal direction and moves it in the longitudinal direction, and a forging press that presses down the forged material in a direction perpendicular to the longitudinal direction, the method comprising: a distance measuring step in which the distance meter is used to measure a distance to an end face of the other longitudinal end of the forged material opposite to the one longitudinal end held by the manipulator before the forged material is moved by the manipulator, and a distance to an end face of the other longitudinal end of the forged material opposite to the one longitudinal end held by the manipulator after the forged material is moved by the manipulator; and a moving distance calculation step of calculating an actual moving distance of the forged material in the longitudinal direction by the manipulator based on the distance measured in the distance measuring step from the distance meter to the end face on the other longitudinal end side of the forged material before the forged material moves and the distance measured in the distance measuring step from the distance meter to the end face on the other longitudinal end side of the forged material after the forged material moves, a display step of displaying, on a display device in real time, the actual movement distance in the longitudinal direction of the forging calculated by the movement distance calculation step together with the input target movement distance; The display step includes an actual movement distance display unit that displays the actual movement distance in the longitudinal direction of the forged material calculated in the movement distance calculation step, a target movement distance input unit that inputs and displays a target movement distance, a target movement distance change input unit that inputs and displays the changed target movement distance when the target movement distance input in the target movement distance input unit is changed, and a movement distance display graph that displays the target movement distance input in the target movement distance input unit or the changed target movement distance input in the target movement distance change input unit, and also displays in real time the actual movement distance in the longitudinal direction of the forged material displayed in the actual movement distance display unit, on the display screen of the display device.

3. A method for manufacturing a forged product, comprising manufacturing the forged product using the method for measuring the moving distance of a forged material according to claim 2.

4. A method for manufacturing a forged product as described in claim 3, characterized in that, by referring to the display device, the longitudinal position of the forged material in the forging press when the actual movement distance in the longitudinal direction of the forged material becomes the target movement distance is determined as a reduction position, and the forged material is reduced by the forging press.

5. the forged product is a stepped cylindrical material having a trunk portion extending in the longitudinal direction, a first shaft portion provided adjacent to the other longitudinal end side of the trunk portion, a second shaft portion provided adjacent to the other longitudinal end side of the first shaft portion, a hanger portion provided adjacent to the other longitudinal end side of the second shaft portion, a third shaft portion provided adjacent to one longitudinal end side of the trunk portion, and a fourth shaft portion provided adjacent to one longitudinal end side of the third shaft portion, 5. The method for manufacturing a forged product according to claim 3, wherein the first shaft portion is formed, the hanging handle portion is formed, and then the second shaft portion is formed by pressing down between the first shaft portion and the hanging handle portion.

Images