Shear hole punching device

Abstract

To form a sheared surface of a hole formed in a workpiece into a cross-sectional shape that protrudes inward.SOLUTION: When a punch 3 advances to form a hole in a workpiece W, the punch 3 enters the workpiece W while a workpiece operating mechanism 4 pushes and extends the workpiece W outward, and the punch 3 advances and penetrates the workpiece W while the workpiece operating mechanism 4 operates to return the workpiece W inward in the middle before the punch 3 penetrates the workpiece W.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a shear punching device that forms a hole by punching a workpiece by shearing. [Background technology]

[0002] 2. Description of the Related Art As a processing device for forming holes in a workpiece, a shear drilling device that forms holes by shearing is known.

[0003] A shear punching device mainly includes a die that supports a workpiece, a holding member that holds the workpiece above the die, and a punch that punches the workpiece to form a hole (see, for example, Patent Document 1: JP 2013-94815 A). The punch advances relative to the workpiece held above the die, and the punch punches out the workpiece, forming a hole (through hole) in the workpiece.

[0004] As shown in Figure 11, the cross section of a hole 10 formed by shearing is usually composed of a surface 11 called a "sag" formed by tensile stress when the punch 3 enters the workpiece W, a relatively smooth shear surface 12 generated by shearing, and a rough fracture surface 13 formed as if the workpiece W had been torn away. Furthermore, when the punch 3 penetrates the workpiece W, a portion called a "burr" may be formed, where part of the workpiece W protrudes. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-94815 Summary of the Invention [Problem to be solved by the invention]

[0006] Depending on the workpiece to be drilled, it may be desirable for the cross-sectional shape of the hole to be formed so as to protrude inward. Generally, methods for forming holes in workpieces include shearing and cutting, but cutting has the problem of being more costly than shearing. On the other hand, shearing has the advantage of being able to form holes inexpensively, but when holes are formed by shearing, the sheared surface is formed in a straight line, making it difficult to form the hole with a cross-sectional shape that protrudes inward.

[0007] Therefore, an object of the present invention is to form the sheared surface of the hole into a cross-sectional shape that protrudes inward. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a shear drilling device comprising: a die that supports the workpiece; a holding member that holds the workpiece above the die; a punch that advances toward the workpiece held by the holding member and punches the workpiece by shearing to form a hole; and a work manipulation mechanism that operates the workpiece to push outward in a direction that intersects the direction of advance of the punch, or to return it inward in the opposite direction to the outward direction, based on the part of the workpiece where the punch abuts, wherein the punch has a reverse tapered portion that becomes thicker toward the tip in the forward direction, and when the punch advances to form a hole in the workpiece, the work manipulation mechanism pushes the workpiece outward as it enters the work, and the work manipulation mechanism operates the work to return the work inward halfway before the punch penetrates the work, while the punch advances and penetrates the work.

[0009] In this way, in the shear drilling device of the present invention, when forming a hole in a workpiece, the punch enters the workpiece while pushing the workpiece outward, and then the punch penetrates the workpiece while operating to return the workpiece inward halfway before penetrating the work, thereby forming a hole with a cross-sectional shape in which the shear surface protrudes toward the inside of the hole. [Effects of the Invention]

[0010] According to the present invention, the shear surface of the hole can be formed into a cross-sectional shape that protrudes toward the inside of the hole. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is an exploded perspective view of a pendulum damper device mounted on an automobile. [Figure 2] FIG. 2 is a cross-sectional view of the pendulum damper device, in which the plate member and the weight member are cut at the position of the roller. [Figure 3] FIG. 10 is a diagram showing a state in which the roller is tilted with respect to the guide groove. [Figure 4] 10A and 10B are diagrams showing a reference example in which the outer peripheral surface of the roller is formed into a convex shape. [Figure 5] 1 is a schematic diagram of a shear drilling device according to an embodiment of the present invention; [Figure 6] FIG. 10 is a diagram for explaining a drilling method. [Figure 7] FIG. 10 is a diagram for explaining a drilling method. [Figure 8] FIG. 10 is a diagram for explaining a drilling method. [Figure 9] FIG. 10 is a diagram showing a modified example of the punch. [Figure 10] FIG. 10 is a diagram showing another modified example of the punch. [Figure 11] FIG. 10 is a cross-sectional view of a hole formed by shearing. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will now be described with reference to the accompanying drawings.

[0013] First, before describing the shear drilling device according to the present invention, an example of a workpiece to be drilled will be described.

[0014] <Configuration of the pendulum damper device> FIG. 1 is an exploded perspective view of a pendulum damper device mounted on an automobile. A pendulum damper device is a device that is placed between an automobile engine and a transmission or a generator to suppress vibrations when the engine is rotating at low speeds.

[0015] 1 , the pendulum damper device 50 mainly includes a plate member 51, weight members 52, rollers 53, and pins 54. The plate member 51 and the weight member 52 are formed with arc-shaped guide grooves 55, 56 into which the rollers 53 are inserted. The plate member 51 is also formed with an arc-shaped elongated hole 57 into which the pins 54 are inserted. The pair of weight members 52 are connected to sandwich the plate member 51 from the front and back sides via the multiple pins 54, so that each weight member 52 is attached to the plate member 51 in a displaceable manner.

[0016] In this state, when the plate member 51 rotates, the rollers 53 move along the guide grooves 55 and 56, causing the weight members 52 to perform pendulum motion so that the radius of rotation changes relative to the plate member 51. This changes the inertia and suppresses vibration.

[0017] FIG. 2 is a cross-sectional view of the pendulum damper device 50 in which the plate member 51 and the weight member 52 are cut at the position of the roller 53.

[0018] 2, roller 53 is inserted into guide grooves 55, 56 of plate member 51 and weight member 52, respectively, and is guided along side surfaces 550, 560 of guide grooves 55, 56. In this way, side surfaces 550, 560 of guide grooves 55, 56 function as guide surfaces that guide roller 53, so in order to stabilize the posture of roller 53 and guide it smoothly, it is desirable that the side surfaces (guide surfaces) 550, 560 of guide grooves 55, 56 be formed with high precision.

[0019] However, when the guide grooves 55, 56 are formed by shear drilling, fracture surfaces 13 as shown in FIG. 11 are formed on the side surfaces 550, 560 of the guide grooves 55, 56. Because such fracture surfaces 13 are roughly inclined, if the fracture surfaces 13 are formed large, the rollers 53 may come into contact with the fracture surfaces 13 and tilt, as shown in FIG. 3. In this case, the rollers 53 are not smoothly guided, which may cause the pendulum motion of the weight members 52 to become unbalanced and vibrations may not be effectively suppressed. Furthermore, if the rollers 53 are guided in an inclined state, slippage (sliding) occurs between the rollers 53 and the guide grooves 55, 56, and this slippage may accelerate wear of the rollers 53 and the guide grooves 55, 56.

[0020] One way to prevent such tilting of roller 53 is to increase the shear surface of guide grooves 55, 56, thereby decreasing the fracture surface. However, when the shear surface increases, the line contact area between guide grooves 55, 56 and roller 53 increases, and these line contact points move in the axial direction depending on the behavior of roller 53, causing a new problem of vibration.

[0021] To address this issue, as shown in FIG. 4 , one solution is to modify the design of roller 53 by forming the outer circumferential surface of roller 53 into a convex shape and making point contact with guide grooves 55, 56. In this case, point contact between roller 53 and guide grooves 55, 56 can prevent the occurrence of vibrations due to variations in the line contact points. However, in this case, the radius of the outer circumferential surface of roller 53 varies along the axial direction of roller 53, so even if roller 53 tilts slightly, the radius of rotation of roller 53 at the contact points between roller 53 and guide grooves 55, 56 changes. Therefore, at points where the radius of rotation of roller 53 is small, slippage of roller 53 occurs between guide grooves 55, 56, which may accelerate wear of roller 53 and guide grooves 55, 56.

[0022] Therefore, in order to suppress the generation of vibration while suppressing wear on the roller 53 and the guide grooves 55, 56, it is better to form the side surfaces 550, 560 of the guide grooves 55, 56 in a convex shape rather than forming the outer peripheral surface of the roller 53 in a convex shape. However, in conventional shear drilling, the sheared surface has a linear cross-sectional shape, making it difficult to form the cross-sectional shape of the hole so that it protrudes inward.

[0023] Therefore, the present invention provides a shear drilling device that can form a cross-sectional shape in which the shear surface of a hole protrudes inward.

[0024] <Configuration of shear drilling equipment> FIG. 5 is a schematic diagram of a shearing drilling device according to one embodiment of the present invention.

[0025] As shown in Figure 5, the shear drilling device 100 of this embodiment includes a die 1 that supports the workpiece W, a holding member 2 that holds the workpiece W on the die 1, a punch 3 that punches the workpiece W by shearing to form a hole, and a work manipulation mechanism 4 that manipulates the workpiece W during drilling.

[0026] The punch 3 is configured to be movable in the vertical direction in Fig. 5 by an elevating mechanism (not shown) or the like. Therefore, the punch 3 moves forward (down) or backward (up) relative to the workpiece W held on the die 1. The punch 3 also has an inverted tapered portion 3a that becomes thicker toward the tip in the forward direction.

[0027] The holding member 2 is a member that presses and holds the workpiece W on the die 1. In the example of Fig. 5, the holding member 2 has a claw-shaped engaging portion 2a that engages with the workpiece W, but the holding member 2 may be any member that can hold the workpiece W so that it does not move relative to the workpiece W.

[0028] The workpiece operating mechanism 4 has a cam member 5 that moves in conjunction with the punch 3 as it advances or retreats. When the punch 3 advances or retreats, the cam member 5 moves in conjunction with the punch 3, moving forward (down) or retreating (up). The tip of the cam member 5 is provided with a pressing portion 5a that presses the pressed portion 2c provided in the recess 2b of the holding member 2. When the cam member 5 advances in conjunction with the punch 3, the pressing portion 5a of the cam member 5 enters the recess 2b of the holding member 2 and presses the pressed portion 2c. Here, the pressing portion 5a and the pressed portion 2c are formed in a convex curved shape, such as an arc-shaped cross section.

[0029] <Drilling method> Next, a drilling method using the shear drilling device according to this embodiment will be described.

[0030] First, as shown in Fig. 5, the workpiece W is placed on the die 1 and held by the holding member 2. In this case, the workpiece W has a through hole 14 formed therein in advance, the through hole 14 being smaller than the tip diameter of the punch 3.

[0031] 6, the punch 3 is advanced (depressed) relative to the workpiece W, and the tip of the punch 3 enters the through hole 14. At this time, the cam member 5 also advances (descends) in conjunction with the advancing punch 3, causing the pressing portion 5a of the cam member 5 to enter the recess 2b of the holding member 2. Then, the pressing portion 5a presses the pressed portion 2c, thereby pushing the holding member 2 in an outward direction (a direction away from the punch 3) that intersects with the advancing direction of the punch 3, and the workpiece W is operated so as to be pushed outward based on the abutment portion of the punch 3. As a result, the through hole 14 expands outward, and the tip of the punch 3 (reverse tapered portion 3a) enters the expanding through hole 14, and the inner surface of the through hole 14 is sheared by the reverse tapered portion 3a of the punch 3.

[0032] 7, when the tip of the punch 3 (reverse tapered portion 3a) passes through a position halfway through the thickness of the workpiece W, the apex of the pressing portion 5a of the cam member 5 passes through the apex of the pressed portion 2c of the holding member 2, and the pressing force of the pressing portion 5a on the holding member 2 is released. This causes the holding member 2 to move back inward (toward the punch 3), opposite the outward direction, and the workpiece W is also operated to contract inward. Therefore, when the tip of the punch 3 passes through a position halfway through the thickness of the workpiece W, the through hole 14 of the workpiece W changes so as to contract inward, and the punch 3 enters the contracting through hole 14, and the inner surface of the through hole 14 is sheared by the reverse tapered portion 3a of the punch 3.

[0033] The punch 3 further advances, and when the tip of the punch 3 (reverse tapered portion 3a) passes through the through-hole 14 as shown in Figure 8, a sheared hole 10 is formed in the workpiece W. At this point, the pressure applied by the pressing portion 5a of the cam member 5 is released, and the holding member 2 is returned to its original position (the state before the pressure was applied).

[0034] As described above, in this embodiment, when drilling a hole in the workpiece W, the punch 3 enters the through hole 14 while pushing the workpiece W outward using the cam member 5 that operates in conjunction with the punch 3, and then, halfway through before the punch 3 penetrates the workpiece W, the punch 3 returns the workpiece W inward as the punch 3 penetrates the workpiece W, thereby forming a hole 10 with a cross-sectional shape that protrudes inward, as shown in Figure 8. In other words, with the shear punching device of this embodiment, the punch 3 is inserted into the expanding and contracting through hole 14, and the operation of inserting the punch 3 into the through hole 14 and the operation of expanding and contracting the through hole 14 are performed simultaneously, thereby forming a hole 10 with a shear surface that protrudes inward.

[0035] As described above, the shear drilling device according to the embodiment of the present invention can form holes 10 having shear surfaces that protrude inward, and therefore, by using the shear drilling device according to the embodiment, the cross-sectional shapes of the side surfaces 550, 560 of the guide grooves 55, 56 can be formed into shapes that protrude inward even in the plate member 51 and weight member 52 described above. Therefore, the shear drilling device according to the embodiment can form the side surfaces 550, 560 of the guide grooves 55, 56 into a convex shape using an inexpensive processing method, ensuring good pendulum motion of the weight member 52.

[0036] As shown in Figure 8, after the punch 3 has penetrated the workpiece W and formed the hole 10, the punch 3 can be retracted (raised) so that the hole 10 is pushed outward by the pressure of the cam member 5 which moves in conjunction with (retracts) the retracting punch 3, thereby allowing the punch 3 to be pulled out while avoiding interference between the punch 3 and the hole 10.

[0037] 9, the reverse tapered portion 3a of the punch 3 preferably has an R-chamfered portion 3b in which the corners of the tip are chamfered in a curved shape, or a C-chamfered portion 3c in which the corners of the tip are chamfered in a linear shape, as shown in FIG. 10. By providing the chamfered portions 3b and 3c on the reverse tapered portion 3a in this manner, wear on the tip of the reverse tapered portion 3a can be suppressed. Furthermore, when the punch 3 has such chamfered portions 3b and 3c, the chamfered portions 3b and 3c can effectively press against the edges of the through hole 14 when the punch 3 enters the through hole 14 in the workpiece W (see FIG. 6). This makes it easier to push the through hole 14 outward and allows the punch 3 to enter the through hole 14 more easily.

[0038] The workpiece W is not limited to a workpiece with a through hole 14 formed therein in advance, and may not have a through hole 14. Even in a workpiece W without a through hole 14, according to the present invention, when the punch 3 advances, the punch 3 advances into the workpiece W while spreading the workpiece W outward, and then the workpiece W is operated so as to return inward, thereby forming a hole 10 whose inner surface protrudes inward, as in the above-described embodiment. However, if the through hole 14 is formed in advance, it is easier to spread the workpiece W, and therefore the load acting on the cam member 5 when spreading the workpiece W can be reduced, making it easier to perform hole drilling with the punch 3.

[0039] The above describes an embodiment of the shearing and drilling device of the present invention, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0040] In the above-described embodiment, the switching when the workpiece W is pushed outward and then returned inward is performed at the timing when the tip of the punch 3 (reverse tapered portion 3a) passes through a position half the thickness of the workpiece W, but the timing of this switching does not necessarily have to be the timing when the tip of the punch 3 passes through a position half the thickness of the workpiece W. Therefore, the timing when the workpiece W is pushed outward and then returned may be before or after the tip of the punch 3 passes through a position half the thickness of the workpiece W.

[0041] Furthermore, the workpiece manipulation mechanism 4 that is operated to spread the workpiece W may be a cam member 5 that interlocks with the punch 3, or an actuator that is driven independently of the punch 3. On the other hand, if the workpiece manipulation mechanism 4 is a cam member 5 that interlocks with the punch 3, there is no need to provide a separate actuator, which has the advantage of simplifying the configuration and reducing costs.

[0042] Furthermore, the shear drilling device according to the present invention can be used not only to form guide grooves 55, 56 in the plate member 51 and weight member 52 of the pendulum damper device 50, but also to drill holes in other parts. [Explanation of symbols]

[0043] 1 die 2. Retaining member 3 Punch 4 Work operation mechanism 5 Cam member 10 holes 100 Shear drilling device double work

Claims

[Claim 1] A die for supporting the workpiece; a holding member for holding the workpiece on the die; a punch that advances toward the workpiece held by the holding member and punches the workpiece by shearing to form a hole; a workpiece manipulation mechanism that manipulates the workpiece so as to push it outward in a direction intersecting the forward movement direction of the punch, or to return it in an inward direction opposite to the outward direction, based on the portion of the workpiece where the punch abuts; A shear drilling device comprising: The punch has a reverse tapered portion that becomes thicker toward the tip in the forward direction, A shear drilling device characterized in that, when the punch advances to form a hole in the workpiece, the workpiece operating mechanism pushes the workpiece apart in the outward direction while the punch enters the workpiece, and the punch advances and penetrates the workpiece while the workpiece operating mechanism operates the workpiece to return in the inward direction midway before the punch penetrates the workpiece.

Images