Upper sub guide, upper wire guide, lower sub guide, and lower wire guide

Abstract

To provide a sub guide which can stably hold a wire electrode and inhibit vibration and positional deviation.SOLUTION: An upper sub guide 33 is provided including: a holding part having a bore diameter larger than a bore diameter of an upper main guide 35; an introduction wall surface which gradually narrows toward the holding part; and a lead-out wall surface which gradually widens from the holding part. In the upper sub guide 33, a cross section of at least a part of the introduction wall surface has a polygonal shape or a shape in which each side of the polygonal shape is curved inward in an arc shape. Alternatively, a lower sub guide 45 is provided including: a holding part having a bore diameter larger than a bore diameter of a lower main guide 43; an introduction wall surface which gradually narrows toward the holding part; and a lead-out wall surface which gradually widens from the holding part. In the lower sub guide 45, a cross section of at least a part of the lead-out wall surface has a polygonal shape or a shape in which each side of the polygonal shape is curved inward in an arc shape.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an upper sub-guide and an upper wire guide including the upper sub-guide, and a lower sub-guide and a lower wire guide including the upper sub-guide, both of which are used in a wire electric discharge machine. [Background technology]

[0002] In electric discharge machining using a wire electric discharge machine, first, a wire electrode is inserted into a pair of wire guides that sandwich the workpiece, and the wire electrode is tensioned. This operation is called wiring. The wire guides guide and position the wire electrode as it is gradually unwound and travels. A voltage is supplied to the tensioned wire electrode via an electric current. Hereinafter, with reference to the workpiece, the wire guide located upstream in the traveling direction of the wire electrode is referred to as the upper wire guide, and the guide located downstream in the traveling direction of the wire electrode is referred to as the lower wire guide. In addition, the member of the wire guide that directly holds the wire electrode is referred to as the guide body. In general, the guide body is made of an insulator with excellent wear resistance, such as diamond or sapphire.

[0003] As disclosed in Patent Document 1, it is known that the through hole of the guide body is composed of a holding portion having a hole diameter slightly larger than the diameter of the wire electrode, an inlet wall surface having a generally inverted conical shape that gradually narrows from the inlet side of the wire electrode toward the holding portion, and an outlet wall surface having a generally conical shape that gradually widens from the holding portion toward the outlet side of the wire electrode. Since the conventional inlet wall surface and outlet wall surface both have circular cross sections, the wire electrode is supported at one point on a certain cross section of the inlet wall surface and at one point on a certain cross section of the outlet wall surface.

[0004] Furthermore, two guide bodies may be provided in each of the upper wire guide and the lower wire guide, as disclosed in Patent Document 2. By guiding the wire electrode with a main guide having a hole diameter slightly larger than the diameter of the wire electrode and a sub-guide having a hole diameter larger than that of the main guide, the wire electrode can be held more stably. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2007-283423 A [Patent Document 2] Japanese Patent Application Publication No. 03-234421 Summary of the Invention [Problem to be solved by the invention]

[0006] One possible way to improve the stability of the wire electrode retention and achieve high-precision machining is to reduce the diameter of the hole in the guide body. However, this would make it difficult to insert the wire electrode, making connection more likely to fail, and would also have the disadvantage of making the wire more likely to break due to the increased contact area with the wire electrode. Therefore, there is a limit to how small the diameter of the guide body can be.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a sub-guide that can stably hold a wire electrode and suppress vibration and misalignment without significantly affecting the wire connection rate or breakage rate. [Means for solving the problem]

[0008] According to the present invention, in a wire electric discharge machine, an upper sub-guide is provided which is located upstream of the workpiece in the traveling direction of the wire electrode and guides the wire electrode together with a main guide, the upper sub-guide having a holding portion having a hole diameter larger than the hole diameter of the upper main guide, an introduction wall surface which gradually narrows from the introduction side of the wire electrode toward the holding portion, and an introduction wall surface which gradually widens from the holding portion toward the introduction side of the wire electrode, and at least a portion of the cross section of the introduction wall surface has a polygonal shape or a shape in which each side of the polygonal shape is curved inward in an arc shape.

[0009] In addition, according to the present invention, there is provided a lower sub-guide for a wire electric discharge machine, which is located downstream of the workpiece in the traveling direction of the wire electrode and guides the wire electrode together with the lower main guide, the lower sub-guide having a holding portion having a hole diameter larger than the hole diameter of the lower main guide, an introduction wall surface that gradually narrows from the introduction side of the wire electrode toward the holding portion, and an introduction wall surface that gradually widens from the holding portion toward the introduction side of the wire electrode, and at least a portion of the cross section of the introduction wall surface has a polygonal shape or a shape in which each side of the polygonal shape is curved inward in an arc shape. Effect of the Invention

[0010] According to the upper subguide of the present invention, the wire electrode is guided along two surfaces of a polygonal shape or a polygonal shape with each side curved inwardly in an arc shape on the introduction wall surface. That is, in a cross section of the introduction wall surface of the upper subguide, the wire electrode is supported at two points. According to the lower subguide of the present invention, the wire electrode is guided along two surfaces of a polygonal shape or a polygonal shape with each side curved inwardly in an arc shape on the introduction wall surface. That is, in a cross section of the introduction wall surface of the lower subguide, the wire electrode is supported at two points. This allows the wire electrode to be stably held, thereby suppressing the occurrence of vibration and positional deviation. Ultimately, machining with higher precision can be achieved. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view of an upper guide unit and a lower guide unit. [Diagram 2] 4 is a cross-sectional view of an upper guide unit and a lower guide unit. FIG. [Diagram 3] FIG. 2 is a side view of the upper wire guide and the lower wire guide. [Figure 4] 4 is a cross-sectional view taken along line IV-IV of FIG. [Diagram 5] 13 shows the first lower guide holder and the second lower guide holder separated. [Figure 6] FIG. [Figure 7]FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. [Figure 8] 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7, showing a state in which the wire electrode has been inserted. [Figure 9] FIG. 4 is a side cross-sectional view of the upper main guide. [Figure 10] FIG. 4 is a side cross-sectional view of the lower main guide. [Figure 11] FIG. [Figure 12] 12 is a cross-sectional view taken along line XII-XII of FIG. 11. [Figure 13] 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12, showing a state in which the wire electrode has been inserted. [Figure 14] FIG. 11 is a top cross-sectional view of an upper sub-guide of a modified example. [Figure 15] FIG. 11 is a bottom cross-sectional view of a lower sub-guide of a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Various modified examples described below can be implemented in any combination.

[0013] 1 and 2 show an upper guide unit 1 and a lower guide unit 2 of a wire electric discharge machine of this embodiment. A workpiece W is placed between the upper guide unit 1 and the lower guide unit 2, and a voltage of the opposite polarity to that applied to the wire electrode E is applied. The wire electrode E, which is stretched between the upper guide unit 1 and the lower guide unit 2, is moved relative to the workpiece W, whereby the workpiece W is electric discharge machined into a desired shape. A machining gap, which is a small gap between the wire electrode E and the workpiece W, is supplied with machining fluid during electric discharge machining. The machining fluid is a dielectric fluid whose main component is pure water or oil.

[0014] The upper guide unit 1 includes a housing 11, a conducting member 13, an upper wire guide 3, and a jet nozzle 15. The housing 11 accommodates the conducting member 13 and the upper wire guide 3 inside. The jet nozzle 15 is attached to the lower surface of the housing 11. The conducting member 13 contacts the wire electrode E upstream of the upper wire guide 3, and a voltage is applied to the wire electrode through the conducting member 13. The conducting member 13 presses the wire electrode E, so that the wire electrode E upstream of the upper wire guide 3 is inclined. The conducting member 13 is configured to be able to move forward and backward, and during wire connection, it moves backward so as not to obstruct the path of the wire electrode E, and after connection is completed, it moves forward and contacts the wire electrode E. The upper wire guide 3 guides and positions the inserted wire electrode E. The jet nozzle 15 sprays machining fluid into the machining gap during electric discharge machining. During connection, the jet nozzle 15 guides the wire electrode E by jetting machining fluid downward.

[0015] The lower guide unit 2 includes a housing 21, a jet nozzle 25, a lower wire guide 4, and a conductor 23. The housing 21 accommodates the lower wire guide 4 and the conductor 23 inside. The jet nozzle 25 is attached to the upper surface of the housing 21. The jet nozzle 25 jets machining fluid into the machining gap during electric discharge machining. The lower wire guide 4 guides and positions the inserted wire electrode E. The conductor 23 contacts the wire electrode E downstream of the lower wire guide 4, and a voltage is applied to the wire electrode through the conductor 13. The conductor 23 presses the wire electrode E, so that the wire electrode E downstream of the lower wire guide 4 is inclined. The conductor 23 is configured to be able to move forward and backward, and during connection, it moves backward so as not to obstruct the path of the wire electrode E, and after connection is completed, it moves forward and contacts the wire electrode E.

[0016] 3 and 4, the upper wire guide 3 includes an upper guide holder 31, an upper sub-guide 33, and an upper main guide 35. The upper guide holder 31 accommodates the upper sub-guide 33 via a support member 337, and accommodates the upper main guide 35 via a support member 357. The upper sub-guide 33 and the upper main guide 35 are guide bodies that directly hold the wire electrode E, and are made of an insulator with excellent wear resistance, such as diamond or sapphire. The support members 337 and 357 are made of an insulator, such as ceramic.

[0017] 3 and 4, the lower wire guide 4 includes a lower guide holder 41, a lower main guide 43, and a lower sub-guide 45. The lower guide holder 41 accommodates the lower main guide 43 via a support member 437, and accommodates the lower sub-guide 45 via a support member 457. The lower main guide 43 and the lower sub-guide 45 are guide bodies that directly hold the wire electrode E, and are made of an insulator having excellent wear resistance, such as diamond or sapphire. The support members 437, 457 are made of an insulator, such as ceramic.

[0018] The upper guide holder 31 may include a side hole 311 for supplying machining fluid between the upper sub-guide 33 and the upper main guide 35. The lower guide holder 41 may include a side hole 413 for supplying machining fluid between the lower main guide 43 and the lower sub-guide 45. When the wire electrode E slides against the upper wire guide 3 and the lower wire guide 4, wire powder may be generated due to scraping off of the surface. By supplying machining fluid to the side hole 311, wire powder accumulated inside the upper wire guide 3 can be discharged from the upper sub-guide 33 side. By supplying machining fluid to the side hole 413, wire powder accumulated inside the lower wire guide 4 can be discharged from the lower sub-guide 45 side. The supply of machining fluid to the side holes 311, 413 may be always performed during electric discharge machining.

[0019] 2 and 4, the conductive member 13, upper sub-guide 33, upper main guide 35, workpiece W, lower main guide 43, lower sub-guide 45, and conductive member 23 are arranged in this order from the upstream side in the traveling direction of the wire electrode E. The upper sub-guide 33 and the upper main guide 35 are located upstream of the workpiece W in the traveling direction of the wire electrode E and guide the wire electrode E. The lower main guide 43 and the lower sub-guide 45 are located downstream of the workpiece W in the traveling direction of the wire electrode E and guide the wire electrode E.

[0020] The guide holder that accommodates the main guide and the guide holder that accommodates the sub-guide may be integrally formed or may be separably formed. In this embodiment, the upper sub-guide 33 and the upper main guide 35 are accommodated in the upper guide holder 31 that is integrally formed. The lower main guide 43 and the lower sub-guide 45 are accommodated in the first lower guide holder 411 and the second lower guide holder 412, respectively, and the first lower guide holder 411 and the second lower guide holder 412 constitute the lower guide holder 41. As shown in FIG. 5, the first lower guide holder 411 and the second lower guide holder 412 are separable. Of course, the upper sub-guide 33 and the upper main guide 35 may be accommodated in different guide holders, and the lower main guide 43 and the lower sub-guide 45 may be accommodated in a guide holder that is integrally formed.

[0021] Although not shown, a thread may be formed on a portion of the upper guide holder 31 and the lower guide holder 41 to facilitate attachment and detachment. A male screw may be formed on the upper portion of the upper guide holder 31 to screw into the housing 11 of the upper guide unit 1. A female screw and a male screw may be formed inside the first lower guide holder 411 and on the upper portion of the second lower guide holder 412 to screw into each other. A male screw may be formed on the lower portion of the second lower guide holder 412 to screw into the housing 21 of the lower guide unit 2.

[0022] The following describes in detail the configuration of the guide body, that is, the upper sub-guide 33, the upper main guide 35, the lower main guide 43, and the lower sub-guide 45. In this specification, unless otherwise specified, the cross section of the guide body refers to a cross section perpendicular to the insertion direction of the wire electrode E, in other words, a cross section perpendicular to the center line of the through hole through which the wire electrode E is inserted.

[0023] As shown in Figs. 6 and 7, the upper sub-guide 33 has a holding portion 331, an introduction wall surface 333, and an exit wall surface 335, and the holding portion 331, the introduction wall surface 333, and the exit wall surface 335 form a through hole. The holding portion 331 has a hole diameter larger than that of the upper main guide 35. The hole diameter of the holding portion 331 may be larger than that of the upper main guide 35, and is, for example, about 0.4 mm. The introduction wall surface 333 has a shape that gradually narrows from the introduction side of the wire electrode E toward the holding portion 331. The exit wall surface 335 has an approximately conical shape that gradually widens from the holding portion 331 toward the exit side of the wire electrode E. The exit wall surface 335 has a circular cross section.

[0024] As shown in FIG. 8, at least a part of the cross section of the introduction wall surface 333 has a polygonal shape. The polygonal shape is preferably a regular polygon. If there are too few vertices, the upper sub-guide 33 becomes large. If there are too many vertices, the interior angles become large, so that the wire electrode E is easily displaced. Therefore, the polygonal shape is preferably any one of a regular hexagon, a regular heptagon, a regular octagon, a regular nonagon, and a regular decagon. According to the upper sub-guide 33 of this embodiment, the wire electrode E tilted by the conductive member 13 is guided along two faces of the polygonal shape of the introduction wall surface 333, so that the wire electrode E is stably held.

[0025] As shown in FIG. 9, the upper main guide 35 has a holding portion 351, an introduction wall surface 353, and an exit wall surface 355, and the holding portion 351, the introduction wall surface 353, and the exit wall surface 355 form a through hole. The holding portion 351 has a hole diameter slightly larger than the diameter of the wire electrode E. The hole diameter of the holding portion 351 is larger than the diameter of the wire electrode E, for example, in a range of about 5 μm to about 20 μm. Depending on the diameter of the wire electrode E, an upper wire guide 3 having an appropriate hole diameter is used. The introduction wall surface 353 has a substantially inverted cone shape that gradually narrows from the introduction side of the wire electrode E toward the holding portion 351. The exit wall surface 355 has a substantially cone shape that gradually widens from the holding portion 351 toward the exit side of the wire electrode E. The introduction wall surface 353 and the exit wall surface 355 have a circular cross section.

[0026] As shown in FIG. 10, the lower main guide 43 has a holding portion 431, an introduction wall surface 433, and an exit wall surface 435, and the holding portion 431, the introduction wall surface 433, and the exit wall surface 435 form a through hole. The holding portion 431 has a hole diameter slightly larger than the diameter of the wire electrode E. The hole diameter of the holding portion 431 is larger than the diameter of the wire electrode E, for example, in a range of about 5 μm to about 20 μm. A lower wire guide 4 having an appropriate hole diameter is used according to the diameter of the wire electrode E. The introduction wall surface 433 has a substantially inverted cone shape that gradually narrows from the introduction side of the wire electrode E toward the holding portion 431. The exit wall surface 435 has a substantially cone shape that gradually widens from the holding portion 431 toward the exit side of the wire electrode E. The introduction wall surface 433 and the exit wall surface 435 have a circular cross section.

[0027] As shown in FIG. 11 and FIG. 12, the lower sub-guide 45 has a holding portion 451, an introduction wall surface 453, and an exit wall surface 455, and the holding portion 451, the introduction wall surface 453, and the exit wall surface 455 form a through hole. The holding portion 451 has a hole diameter larger than that of the lower main guide 43. The hole diameter of the holding portion 451 may be larger than that of the lower main guide 43, and is, for example, about 0.6 mm. The introduction wall surface 453 has a substantially inverted cone shape that gradually narrows from the introduction side of the wire electrode E toward the holding portion 451. The exit wall surface 455 has a shape that gradually widens from the holding portion 451 toward the exit side of the wire electrode E. The introduction wall surface 453 has a circular cross section.

[0028] As shown in FIG. 13, at least a part of the cross section of the lead-out wall surface 455 has a polygonal shape. The polygonal shape is preferably a regular polygon. If there are too few vertices, the lower sub-guide 45 becomes large. If there are too many vertices, the interior angles become large, so that the wire electrode E is easily displaced. Therefore, the polygonal shape is preferably any one of a regular hexagon, a regular heptagon, a regular octagon, a regular nonagon, and a regular decagon. According to the lower sub-guide 45 of this embodiment, the wire electrode E tilted by the conductive member 23 is guided along two faces of the polygonal shape of the lead-out wall surface 455, so that the wire electrode E is stably held.

[0029] The present invention is not limited to the configurations of the embodiments described above, and various modifications and applications are possible without departing from the technical spirit of the present invention.

[0030] For example, as shown in Fig. 14, at least a part of the cross section of the introduction wall surface 333 of the upper sub-guide 33 may have a shape in which each side of the polygonal shape is curved inwardly in an arc shape, instead of a polygonal shape. Also, as shown in Fig. 15, at least a part of the cross section of the extraction wall surface 455 of the lower sub-guide 45 may have a shape in which each side of the polygonal shape is curved inwardly in an arc shape, instead of a polygonal shape. Even in this case, the wire electrode E is guided along two surfaces, so that the wire electrode E is stably held.

[0031] In the present embodiment, the guide bodies have direct contact between the outlet wall surfaces, and the holding portion is a planar circular hole that has substantially no height. The holding portion may be configured as a cylindrical hole, but from the viewpoint of preventing breakage of the wire electrode E, it is preferable that the contact area with the wire electrode E is as small as possible, and therefore the holding portion is preferably a planar hole. [Explanation of symbols]

[0032] 3 Upper Wire Guide 31 Upper guide holder 311 Side hole 33 Upper sub guide 331 Holding part 333 Introduction wall 335 Outlet Wall 35 Upper main guide 4 Lower Wire Guide 41 Lower guide holder 413 Side hole 43 Lower main guide 45 Lower sub guide 451 Holding part 453 Introduction wall 455 Outlet wall E Wire Electrode W Workpiece

Claims

1. In a wire electric discharge machine, an upper sub-guide is located upstream of a workpiece in a traveling direction of a wire electrode, and guides the wire electrode together with an upper main guide, a holding portion having a hole diameter larger than the hole diameter of the upper main guide; an introduction wall surface that gradually narrows from an introduction side of the wire electrode toward the holding portion; a lead-out wall surface that gradually widens from the holding portion toward the lead-out side of the wire electrode, An upper sub-guide, wherein a cross section of at least a portion of the introduction wall surface has a polygonal shape or a shape in which each side of the polygonal shape is curved inwardly in an arc shape.

2. The upper subguide according to claim 1 , wherein the polygonal shape is any one of a regular hexagon, a regular heptagon, a regular octagon, a regular nonagon, and a regular decagon.

3. An upper sub-guide according to claim 1 ; The upper main guide; and an upper guide holder that houses the upper sub-guide and the upper main guide.

4. The upper wire guide according to claim 3 , wherein the upper guide holder includes a side hole for supplying machining fluid between the upper sub-guide and the upper main guide.

5. In a wire electric discharge machine, a lower sub-guide is located downstream of a workpiece in a traveling direction of a wire electrode, and guides the wire electrode together with a lower main guide, a holding portion having a hole diameter larger than the hole diameter of the lower main guide; an introduction wall surface that gradually narrows from an introduction side of the wire electrode toward the holding portion; a lead-out wall surface that gradually widens from the holding portion toward the lead-out side of the wire electrode, A lower sub-guide, wherein a cross section of at least a portion of the outlet wall surface has a polygonal shape or a shape in which each side of the polygonal shape is curved inwardly in an arc shape.

6. The lower subguide according to claim 5 , wherein the polygonal shape is any one of a regular hexagon, a regular heptagon, a regular octagon, a regular nonagon, and a regular decagon.

7. A lower sub-guide according to claim 5; The lower main guide; a lower guide holder that houses the lower main guide and the lower sub-guide.

8. The lower wire guide according to claim 7 , wherein the lower guide holder includes a side hole for supplying machining fluid between the lower main guide and the lower sub-guide.

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