Bending radius measuring device and bending radius measuring method

Abstract

The present invention provides a bending radius measuring device and a bending radius measuring method that can automatically and accurately measure the minimum bending radius of a rod-shaped object. [Solution] The bending radius of the rod-shaped body 2 is measured using a measuring device 1 which includes a first support member 11 that supports one end of the rod-shaped body 2, a second support member 12 that supports the other end of the rod-shaped body 2, a bending mechanism 14 which has a gripping part 13 that grips the longitudinal center of the rod-shaped body 2 and bends the rod-shaped body 2 by moving the gripping part 13 downward while gripping the rod-shaped body 2, a pair of clamping plates 15a, 15b which are arranged opposite each other and can move in directions toward or away from each other and clamp the rod-shaped body 2 bent by the bending mechanism 14 from the side so that it becomes a substantially U shape, a load measuring unit 16 which measures the load on the pair of clamping plates 15a, 15b, and a movement amount measuring unit 17 which measures the distance moved by the pair of clamping plates 15a, 15b.

Description

Technical Field

[0001] The present invention relates to an apparatus and a method for measuring a bending radius of a rod-shaped body.

Background Art

[0002] The minimum bending (flexure) radius is the limit inner radius at which a member can be bent without causing cracking or splitting. For example, in the case of a rod-shaped body such as a pipe, a tube, or a round bar, after forming the object to be measured (the rod-shaped body) into an annular shape, the object is gradually bent, and the diameter (R) of the annular inner diameter when the deformation rate (flattening rate) at the bending apex reaches 10% is read, and one half of this diameter is taken as the minimum bending radius (see Patent Document 1).

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] Conventionally, for a rod-shaped body having a flexural modulus of approximately 35 to 100 GPa, the minimum bending radius has been calculated by manually bending the measurement object, confirming the occurrence of cracking noise or buckling with the measurer's own ears and eyes, and measuring the inner diameter at that time. However, with conventional measurement methods, since judgment criteria, bending methods, force application methods and the like differ every time measurement is performed, there is a problem that errors are likely to occur in the measurement results of the minimum bending radius. Further, in the case of a method of bending into an annular shape by crossing both ends like the measurement method described in Patent Document 1, when the minimum bending radius is 400 mm or more, there is also a problem that much labor is required and the number of man-hours increases.

[0005] Therefore, an object of the present invention is to provide a bending radius measuring apparatus and a bending radius measuring method capable of automatically and accurately measuring the minimum bending radius of a rod-shaped body.

Means for Solving the Problem

[0006] The bending radius measuring device according to the present invention is a device for measuring the bending radius of a rod-shaped body, comprising: a first support member that supports one end of the rod-shaped body; a second support member that supports the other end of the rod-shaped body; a bending mechanism that grips the central part of the rod-shaped body in the longitudinal direction, and in which the gripping part moves downward while gripping the rod-shaped body, thereby bending the rod-shaped body; a pair of clamping plates that are arranged opposite each other, are movable in directions toward or toward each other, and clamp the rod-shaped body bent by the bending mechanism from the side so that it becomes substantially U-shaped; a load measuring unit that measures the load applied to the pair of clamping plates; and a movement amount measuring unit that measures the distance moved by the pair of clamping plates. The pair of clamping plates may each be fitted with a first and a second fixing member for fixing the rod-shaped body. Furthermore, the bending radius measuring device of the present invention may further include a control unit that controls the operation of the bending mechanism and the pair of clamping plates. The control unit, for example, moves the pair of clamping plates toward each other after releasing the grip of the rod-shaped body by the bending mechanism. The control unit may also further control the operation of the first and second fixing members. In this case, the control unit may, for example, temporarily stop the movement of the clamping plates when the distance between the fulcrums of the rod-shaped body is in the range of 30 to 70% of the length of the rod-shaped body, and then fix the rod-shaped body with the first and second fixing members. The bending radius measuring device of the present invention may have guide grooves formed on the surfaces of the pair of clamping plates that come into contact with the rod-shaped body, for accommodating the rod-shaped body. The bending radius measuring device of the present invention further includes a calculation unit for calculating the minimum bending radius of the rod-shaped body, and the calculation unit may determine the minimum bending radius of the rod-shaped body from the yield point of the load measured by the load measuring unit and the amount of movement of the clamping plate measured by the movement amount measuring unit.

[0007] The bending radius measurement method according to the present invention is a method for measuring the minimum bending radius of a rod-shaped body using a bending radius measuring device, comprising the steps of: placing one end and the other end of the rod-shaped body on a first support member and a second support member of the bending radius measuring device, respectively; gripping the longitudinal center of the rod-shaped body with a gripping part of the bending mechanism of the bending radius measuring device, and bending the rod-shaped body by moving the gripping part downward while gripping the rod-shaped body; releasing the grip of the rod-shaped body by the bending mechanism, and then moving a pair of clamping plates provided on the bending radius measuring device toward each other to clamp the rod-shaped body bent by the bending mechanism from the side so that it becomes substantially U-shaped; and measuring the load applied to the clamping plates and the amount of movement of the clamping plates while moving the pair of clamping plates toward each other, and calculating the minimum bending radius of the rod-shaped body from the yield point of the load and the amount of movement of the clamping plates at that time. [Effects of the Invention]

[0008] According to the present invention, it is possible to automatically and accurately measure the minimum bending radius of a rod-shaped body. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example configuration of a bending radius measuring device according to an embodiment of the present invention. [Figure 2] Figure 1 shows the operation of the bending radius measuring device 1. [Figure 3] This flowchart shows each step of the bending radius measurement method according to an embodiment of the present invention. [Modes for carrying out the invention]

[0010] The embodiments for carrying out the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below.

[0011] First, a bending radius measuring device (hereinafter also simply referred to as "measuring device") according to an embodiment of the present invention will be described. Figure 1 is a diagram showing an example of the configuration of the bending radius measuring device of this embodiment, and Figure 2 is a diagram showing the operation of the bending radius measuring device 1 shown in Figure 1. As shown in Figure 1, the measuring device 1 of this embodiment measures the bending radius of a rod-shaped body 2, and comprises support members 11 and 12 that support the rod-shaped body 2 which is the object to be measured, a bending mechanism 14 that bends the rod-shaped body 2, a pair of clamping plates 15a and 15b that clamp the rod-shaped body 2, a load measuring unit 16 that measures the load applied to the clamping plates 15a and 15b, and a movement amount measuring unit 17 that measures the distance traveled by the clamping plates 15a and 15b.

[0012] Furthermore, in addition to the above-described configurations, the measuring device 1 of this embodiment may also be equipped with a control unit 18 that controls the operation of the bending mechanism 14 and the clamping plates 15a, 15b, and / or a calculation unit 19 that calculates the minimum bending radius of the object to be measured (rod-shaped body 2).

[0013] [Rod-shaped object 2] The rod-shaped body 2 is the object to be measured (object to be measured) of the measuring device 1 of this embodiment, and examples include hollow rod-shaped bodies such as tubes and pipes, and solid rod-shaped bodies such as round rods made of fiber-reinforced resin or synthetic resin. The measuring device 1 of this embodiment is particularly suitable for measuring the bending radius of fiber-reinforced rigid resin rod-shaped bodies with high bending rigidity.

[0014] The material, length, and cross-sectional shape of the rod-shaped body 2 are not particularly limited, but it is preferable that it can be placed on the support members 11 and 12 without twisting and that it can be clamped by the clamping plates 15a and 15b without twisting. Also, if it is desirable to save space in the measuring device 1, it is preferable to keep the length of the rod-shaped body 2 to 2200 mm or less.

[0015] [Support members 11, 12] Support members 11 and 12 each support the end of the rod-shaped body 2 and are fixed, for example, to the upper part of a frame 21 installed on a base 20 by bolts or the like. Support members 11 and 12 are at the same distance (same height) from the base 20 and are attached at a predetermined interval to match the end of the rod-shaped body 2. Furthermore, the configuration of support members 11 and 12 is not particularly limited as long as they can support the end of the rod-shaped body 2 from below, but it is preferable that recesses (grooves) are formed in the parts on which the rod-shaped body 2 is placed. This allows for stable support while suppressing rolling, even if the rod-shaped body 2 is a round bar with a circular cross-section.

[0016] [Bending mechanism 14] The bending mechanism 14 includes a gripping portion 13 that grips the longitudinal center of the rod-shaped body 2, and the rod-shaped body 2 is bent by moving the gripping portion 13 downward while gripping the rod-shaped body 2. The configuration of the bending mechanism 14 is not particularly limited, but for example, the gripping portion 13 can be attached to the slider portion of a slider-type electric actuator. In this case, the rod-shaped body 2 can be bent by gripping the rod-shaped body 2 with the gripping portion 13 and then operating the electric actuator to move the slider portion downward.

[0017] The gripping portion 13 of the bending mechanism 14 should be capable of gripping the rod-shaped body 2 and releasing the grip at any desired timing. The material of the gripping portion 13 is not particularly limited, but it is preferably made of a resin material such as a fluororesin or a polyamide resin, which can improve the sliding properties with the rod-shaped body 2.

[0018] [Holding plates 15a, 15b] The holding plates 15a and 15b are respectively disposed opposite to each other in the length direction of the rod-shaped body 2 around the bending mechanism 14. For example, the upper part and the lower part thereof are supported by linear rails 23a and 23b, and by pushing and pulling the central part with screw jacks 24a and 24b, the holding plates can move horizontally in a direction toward or away from each other. In the measuring apparatus 1 of the present embodiment, as shown in Fig. 2, the rod-shaped body 2 bent by the bending mechanism 14 is sandwiched from the sides by the holding plates 15a and 15b, and in this state, the holding plates 15a and 15b are moved in a direction approaching each other, thereby further bending the rod-shaped body 2 into a substantially U-shape.

[0019] It is preferable that a guide groove extending in the bending direction (a direction perpendicular to the pedestal surface) is formed on the surface of the holding plates 15a and 15b that is in contact with the rod-shaped body 2. This guide groove accommodates the rod-shaped body 2 and prevents the rod-shaped body 2 from shifting or coming off during a bending operation. The shape of the guide groove is not particularly limited, and it may be a U-shaped groove or a V-shaped groove in addition to a square groove with a rectangular cross-section. In addition, the width and depth of the guide groove can be appropriately set according to the size of the rod-shaped body 2. For example, when the outer diameter of the rod-shaped body is 3 to 14 mm, the depth of the guide groove may be 4 to 15 mm.

[0020] In addition, for the holding plates 15a and 15b, it is preferable that at least the inner surface of the guide groove in contact with the rod-shaped body 2 is formed of a resin material such as fluororesin or polyamide resin. This can improve the sliding performance with the rod-shaped body 2. Furthermore, fixing members 22a and 22b for fixing the rod-shaped body 2 may be respectively attached to the upper parts of the holding plates 15a and 15b. As shown in Fig. 2, by gripping and fixing the end portions of the rod-shaped body 2 with the fixing members 22a and 22b, it is possible to prevent the rod-shaped body 2 from shifting in the lateral direction or coming off from the holding plates 15a and 15b during a bending operation.

[0021] [Load Measuring Unit 16] The load measuring unit 16 measures the load applied to the clamping plates 15a and 15b, and can use, for example, a load cell. In the measuring device 1 of this embodiment, the load measuring unit 16 measures the buckling load (springback load) when the rod-shaped body 2 is bent, and calculates the minimum bending radius from the bending radius at which the yield point occurs.

[0022] [Movement measurement section 17] The movement measurement unit 17 measures the distance traveled by the clamping plates 15a and 15b, and can use, for example, an encoder. In that case, the distance traveled by the clamping plates 15a and 15b can be determined, for example, by attaching encoders to the screw jacks 24a and 24b that move the clamping plates 15a and 15b and measuring the amount of movement of the screw jacks 24a and 24b.

[0023] [Control Unit 18] The control unit 18 controls the operation of the measuring device 1 in this embodiment, specifically controlling the operation of bending the rod-shaped body 2 with the bending mechanism 14, the operation of bending the rod-shaped body 2 with the clamping plates 15a and 15b, and the operation of fixing the rod-shaped body 2 with the fixing members 22a and 22b.

[0024] For example, after the bending mechanism 14 releases its grip on the rod-shaped body 2, the control unit 18 controls the screw jacks 24a, 24b, etc., so that the clamping plates 15a, 15b move toward each other. If the rod-shaped body 2 is continued to bend while the gripping part 13 grips the central part, it is not possible to accurately measure the minimum bending radius. Therefore, when the distance between the support points reaches a predetermined value, the control unit 18 releases the grip from the gripping part 13 and changes to a method of clamping with the clamping plates 15a, 15b. This makes it possible to measure the minimum bending radius with high accuracy. It is preferable that the control unit 18 controls the bending mechanism 14 so that the gripping part 13, after releasing its grip, moves upward.

[0025] Furthermore, the control unit 18 can temporarily stop the movement of the clamping plates 15a and 15b when the distance between the support points of the rod-shaped body 2 is in the range of 30-70% of the length of the rod-shaped body 2, and fix the rod-shaped body 2 with the fixing members 22a and 22b. For example, if a rod-shaped body 2 with a length of 2200 mm is bent into a U shape with a support point distance of 1500 mm, the bending radius is too large, making it impossible for the fixing members 22a and 22b to fix both ends of the rod-shaped body 2 almost vertically. On the other hand, if the bending operation is temporarily stopped at 30-70% of the support point distance (about 700 mm), and the distance between the stopping clamping plates 15a and 15b is brought closer to about 1000 mm, the fixing members 22a and 22b and the rod-shaped body 2 will be almost vertical, making it possible to accurately grip both ends.

[0026] Furthermore, if the length of the rod-shaped body 2 is 2500 mm or more, the gripping portion 13 can be lowered by 1000 mm to make the fixing members 22a and 22b and the rod-shaped body 2 nearly perpendicular, so it is not necessary to temporarily stop the bending operation.

[0027] [Calculation section 19] The calculation unit 19 determines the minimum bending radius of the rod-shaped body 2 from the yield point of the load measured by the load measuring unit 16 and the amount of movement of the clamping plates 15a and 15b measured by the displacement measuring unit 17. The minimum bending radius of the rod-shaped body 2 calculated by the calculation unit 19 can be output to, for example, a display unit provided in the device or a display device connected to the measuring device 1.

[0028] [Operation] Next, a method for measuring the minimum bending radius of a rod-shaped body 2 using the bending radius measuring device 1 of this embodiment will be described. Figure 3 is a flowchart showing each step of the bending radius measuring method of this embodiment. As shown in Figure 3, the measurement method of this embodiment includes the steps of: placing the rod-shaped body 2, which is the object to be measured, on the support members 11 and 12 of the measuring device 1 (placing step S1); bending the rod-shaped body 2 to a predetermined position (bending step S2); clamping the rod-shaped body 2 with clamping plates 15a and 15b and bending it to the bending point (clamping step S3); and calculating the minimum bending radius (calculation step S4).

[0029] [Placement process S1] In the bending radius measurement method of this embodiment, first, one end and the other end of the rod-shaped body 2 are placed on the support members 11 and 12 of the bending radius measuring device 1, respectively.

[0030] [Bending process S2] Next, the gripping portion 13 of the bending mechanism 14 of the bending radius measuring device 1 grips the longitudinal center of the rod-shaped body 2, and the rod-shaped body 2 is bent by moving the gripping portion 13 downwards while gripping the rod-shaped body 2.

[0031] [Pinching process S3] Next, the bending mechanism 14 releases its grip on the rod-shaped body 2, and the pair of clamping plates 15a and 15b provided on the bending radius measuring device 1 are moved toward each other to clamp the rod-shaped body 2, which has been bent by the bending mechanism 14, from the side.

[0032] [Calculation process S4] Then, while moving the clamping plates 15a and 15b toward each other, the load on the clamping plates 15a and 15b and the amount of movement of the clamping plates 15a and 15b are measured, and the minimum bending radius of the rod-shaped body 2 is calculated from the yield point of the load and the amount of movement of the clamping plates 15a and 15b at that time. Specifically, the minimum bending diameter is the value obtained by subtracting the amount of movement of the encoder from the initial distance between the clamping plates 15a and 15b, so half of that value is calculated as the minimum bending radius.

[0033] Furthermore, with materials that have a high bending modulus, if the distance between supports is short, cracks or fractures may occur when the material is bent into a U-shape, making it difficult to accurately measure the bending radius. Therefore, in the bending radius measurement method of this embodiment, when measuring a rod-shaped body with a bending modulus of approximately 3 to 100 GPa, it is preferable to set the distance between supports to 1500 mm or more.

[0034] Furthermore, in the bending radius measurement method of this embodiment, it is preferable to temporarily stop the movement of the clamping plates 15a and 15b when the distance between the support points of the rod-shaped body 2 is in the range of 30 to 70% of the length of the rod-shaped body 2, and to fix the rod-shaped body 2 with the fixing members 22a and 22b. This ensures that both ends of the rod-shaped body 2 are securely fixed by the fixing members 22a and 22b, preventing the rod-shaped body 2 from shifting or detaching during bending, and enabling accurate measurement of the minimum bending radius.

[0035] As detailed above, the bending radius measuring device of this embodiment allows for automated processing of subsequent steps once the object to be measured is set in a predetermined position, thus reducing the need for manual bending radius measurement and improving work efficiency. Furthermore, since the bending operation is performed in two stages—pressing down the central part by the bending mechanism and clamping with a pair of clamping plates—it is possible to accurately measure the minimum bending radius of the rod-shaped object. Moreover, by providing guide grooves and fixing members on the clamping plates, the displacement and detachment of the rod-shaped object to be measured during bending can be prevented, further improving measurement accuracy.

[0036] Furthermore, the present invention may also take the following forms. [1] A device for measuring the bending radius of a rod-shaped object, A first support member that supports one end of the rod-shaped body, A second support member that supports the other end of the rod-shaped body, A bending mechanism comprising a gripping portion that grips the central part of the rod-shaped body in the longitudinal direction, wherein the gripping portion moves downward while gripping the rod-shaped body to bend the rod-shaped body, A pair of clamping plates are positioned opposite each other, are movable in directions toward or toward each other, and clamp the rod-shaped body, which has been bent by the bending mechanism, from the side so that it becomes substantially U-shaped, A load measuring unit for measuring the load applied to the pair of clamping plates, A movement amount measuring unit for measuring the distance traveled by the pair of clamping plates A bending radius measuring device equipped with the following features. [2] The bending radius measuring device according to [1], wherein a first and second fixing member for fixing the rod-shaped body is attached to the pair of clamping plates, respectively. [3] Furthermore, the bending radius measuring device according to [1] or [2] further comprises a control unit that controls the operation of the bending mechanism and the pair of clamping plates. [4] The bending radius measuring device according to [3], wherein the control unit releases the grip of the rod-shaped body by the bending mechanism and then moves the pair of clamping plates toward each other. [5] The bending radius measuring device according to [3] or [4], wherein the control unit further controls the operation of the first and second fixing members. [6] The bending radius measuring device according to [5], wherein the control unit temporarily stops the movement of the clamping plate when the distance between the support points of the rod-shaped body is in the range of 30 to 70% of the length of the rod-shaped body, and fixes the rod-shaped body with the first and second fixing members. [7] A bending radius measuring device according to any one of [1] to [6], wherein a guide groove for accommodating the rod-shaped body is formed on the surface of the pair of clamping plates that contacts the rod-shaped body. [8] Furthermore, it includes a calculation unit for calculating the minimum bending radius of the rod-shaped body, The bending radius measuring device according to any one of [1] to [7], wherein the calculation unit determines the minimum bending radius of the rod-shaped body from the yield point of the load measured by the load measuring unit and the amount of movement of the clamping plate measured by the movement measuring unit. [9] A method for measuring the minimum bending radius of a rod-shaped body using a bending radius measuring device, The process involves placing one end and the other end of the rod-shaped body on the first support member and the second support member provided on the bending radius measuring device, respectively. The bending radius measuring device comprises the steps of: gripping the central part of the rod-shaped body in the longitudinal direction with the gripping part of the bending mechanism provided in the bending radius measuring device, and bending the rod-shaped body by moving the gripping part downward while gripping the rod-shaped body; After releasing the grip of the rod-shaped body by the bending mechanism, the pair of clamping plates provided on the bending radius measuring device are moved toward each other, thereby clamping the rod-shaped body, which has been bent by the bending mechanism, from the side so that it becomes approximately U-shaped. The process involves moving the pair of clamping plates toward each other, measuring the load on the clamping plates and the amount of movement of the clamping plates, and calculating the minimum bending radius of the rod-shaped body from the yield point of the load and the amount of movement of the clamping plates at that point. A method for measuring the radius of bending, comprising the following characteristics. [Explanation of symbols]

[0037] 1 Bending radius measuring device (measuring device) 2 Rod-shaped object (object to be measured) 11,12 Support members 13 Gripping part 14 Bending mechanism 15a,15b Holding plate 16 Load measurement section 17 Travel measurement section 18 Control Unit 19 Calculation Section 20 bases 21 Frame 22a, 22b Fixing members 23a, 23b Linear rail 24a, 24b Screw jack

Claims

1. A device for measuring the bending radius of a rod-shaped object, A first support member that supports one end of the rod-shaped body, A second support member that supports the other end of the rod-shaped body, A bending mechanism comprising a gripping portion that grips the central part of the rod-shaped body in the longitudinal direction, wherein the gripping portion moves downward while gripping the rod-shaped body to bend the rod-shaped body, A pair of clamping plates are positioned opposite each other, are movable in directions toward or toward each other, and clamp the rod-shaped body, which has been bent by the bending mechanism, from the side so that it becomes substantially U-shaped, A load measuring unit for measuring the load applied to the pair of clamping plates, A movement amount measuring unit for measuring the distance traveled by the pair of clamping plates A bending radius measuring device equipped with the following features.

2. The bending radius measuring device according to claim 1, wherein a first and second fixing member for fixing the rod-shaped body is attached to the pair of clamping plates, respectively.

3. Furthermore, the bending radius measuring device according to claim 1 or 2 further comprises a control unit that controls the operation of the bending mechanism and the pair of clamping plates.

4. The bending radius measuring device according to claim 3, wherein the control unit moves the pair of clamping plates toward each other after releasing the grip of the rod-shaped body by the bending mechanism.

5. The bending radius measuring device according to claim 3, wherein the control unit further controls the operation of the first and second fixing members.

6. The bending radius measuring device according to claim 5, wherein the control unit temporarily stops the movement of the clamping plate when the distance between the fulcrums of the rod-shaped body is in the range of 30 to 70% of the length of the rod-shaped body, and fixes the rod-shaped body with the first and second fixing members.

7. The bending radius measuring device according to claim 1, wherein a guide groove for accommodating the rod-shaped body is formed on the surface of the pair of clamping plates that contacts the rod-shaped body.

8. Furthermore, it includes a calculation unit for calculating the minimum bending radius of the rod-shaped body, The bending radius measuring device according to claim 1, wherein the calculation unit determines the minimum bending radius of the rod-shaped body from the yield point of the load measured by the load measuring unit and the amount of movement of the clamping plate measured by the movement amount measuring unit.

9. A method for measuring the minimum bending radius of a rod-shaped body using a bending radius measuring device, The process involves placing one end and the other end of the rod-shaped body on the first support member and the second support member provided on the bending radius measuring device, respectively. The bending radius measuring device comprises the steps of: gripping the central part of the rod-shaped body in the longitudinal direction with the gripping part of the bending mechanism provided in the bending radius measuring device, and bending the rod-shaped body by moving the gripping part downward while gripping the rod-shaped body; After releasing the grip of the rod-shaped body by the bending mechanism, the pair of clamping plates provided on the bending radius measuring device are moved toward each other, thereby clamping the rod-shaped body, which has been bent by the bending mechanism, from the side so that it becomes approximately U-shaped. The process involves moving the pair of clamping plates toward each other, measuring the load on the clamping plates and the amount of movement of the clamping plates, and calculating the minimum bending radius of the rod-shaped body from the yield point of the load and the amount of movement of the clamping plates at that point. A method for measuring the radius of bending, comprising the following characteristics.

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