JP6151978B2 - Small hole electric discharge machine - Google Patents

Description

  The present invention relates to a fine hole electric discharge machining apparatus. More specifically, the present invention relates to a small hole electric discharge machining apparatus that uses a pipe or a rod-like electrode to machine a tapered hole having a hole diameter that increases from the machining hole inlet toward the outlet.

  As a narrow hole electric discharge machining apparatus for machining a tapered hole whose hole diameter increases from the machining hole entrance to the exit, for example, Patent Document 1 discloses a lower part that pivotally supports the lower end of a rod-like electrode in the vicinity of the upper part of the workpiece. An electric motor provided with an electrode guide and an upper electrode guide (eccentric guide means) for providing circular motion with the lower electrode guide as a fulcrum to the electrode above the lower electrode guide, and disposed adjacent to the upper electrode guide Discloses a configuration for rotationally driving the upper electrode guide.

  Note that in a fine hole electric discharge machining apparatus using a pipe or a rod-like electrode, water or pure water is usually used as a high-pressure machining fluid for discharging and cooling machining scraps.

JP 2010-131688 A

  As described above, in Patent Document 1, an electric motor is conventionally used as the rotational drive means of the upper electrode guide (eccentric guide means) that gives the electrode a circular motion with the lower electrode guide as a fulcrum above the lower electrode guide. ing.

  However, as shown in Patent Document 1, in a narrow hole electric discharge machining apparatus that uses water as a machining fluid, an electric motor that is a drive source adjacent to an upper electrode guide (eccentric guide means) located near the machining fluid is scattered. Has a problem that water easily penetrates into the electric motor or the electric wiring part, and a failure due to poor insulation or the like is likely to occur.

  Moreover, if waterproofing measures are applied to the electric motor and the electric wiring section, the apparatus becomes larger and the manufacturing cost increases. In addition, there is a problem in that the loss of the electrode increases because the length of the electrode that exists in the electrode guide portion and cannot be used for processing becomes long.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to process a tapered hole that uses a pipe or a rod-like electrode and whose hole diameter increases from the processing hole inlet to the outlet. In a small hole electric discharge machining apparatus that uses high-pressure water as the machining fluid in the above, a more compact rotation drive means that does not use an electric motor that causes a failure due to water intrusion in the rotation drive means of the upper electrode guide (eccentric guide means) It is to provide a fine hole electric discharge machining apparatus.

The thin hole electric discharge machining apparatus according to claim 1 is a thin hole electric discharge machining apparatus for machining a tapered hole whose hole diameter increases from the upper surface to the lower surface of the workpiece, as a means for solving the above-described problem, An electrode holder that is rotatable by holding the upper end of a rod-shaped or pipe-shaped electrode on a positionable spindle, a housing disposed below the electrode holder, and a machining center provided on the lower surface of the housing coaxial and the lower electrode guide, Oite between the lower electrode guide and the electrode holder, with respect to the housing, and an upper electrode guide rotatably disposed at a position eccentric from the processing center by a bearing , provided below the bearing, and a rotation driving means for pivoting the upper electrode guide around the processing center, said pivot drive means comprises a high pressure It is characterized in that a turbine that is rotated by application liquid.
The thin hole electric discharge machining apparatus according to claim 1 , further comprising a hole for dropping a machining fluid obtained by rotating the turbine .
Further, a small hole electric discharge machining apparatus according to claim 1 or claim 2, wherein the having the eccentricity adjusting mechanism for adjusting the eccentricity amount before Symbol upper electrode guide.

  According to the present invention, since the high-pressure machining fluid used for discharging and cooling the machining waste is used as the driving force of the turbine that rotates the upper guide member around the machining center, There is no need for a waterproof mechanism for the rotary drive.

  Further, since the driving force for the turning drive can be obtained from the high-pressure machining fluid, there is no waste, and a compact thin hole electric discharge machining apparatus with reduced manufacturing costs can be provided.

The front view of the lower electrode guide apparatus 1 of the fine hole electric discharge machining apparatus which concerns on this invention. AA sectional drawing in FIG. The bottom view of FIG. BB sectional drawing in FIG. Explanatory drawing of eccentric amount adjustment of the upper electrode guide 20. FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  Referring to FIGS. 1 and 2, the housing 3 of the lower electrode guide device 1 is provided on a support plate 4 provided at the lower end of a slide base (not shown) of the narrow hole electric discharge machining apparatus.

  Above the lower electrode guide device 1, an electrode holder that holds the upper end of a rod-like or pipe-like electrode 5 on a spindle (not shown) that can be positioned in the vertical direction and feeds it downward while rotating the electrode 5. 7 is provided.

A cylindrical drive shaft 9 extending from the upper portion of the housing 3 to the lower end portion is rotatably supported by the housing 3 of the lower electrode guide device 1 by a pair of bearings 11 (a, b). A spacer 13 is provided between the pair of bearings 11a and 11b, and the upper bearing 11a is fixed to the housing 3 by a C-shaped retaining ring 15. Further, in the cylinder of the drive shaft 9, the drive shaft 9 A bottomed cylindrical eccentric rotary shaft 19 having a rotational center O ₂ (see FIG. 5) at a position eccentric by a distance “e” from the rotation center (processing center) 17 (= O ₁ , see FIG. 5) is the drive shaft. 9 is rotatably inserted into the cylinder.

The eccentric rotation shaft 19 is provided with an upper electrode guide 20 at a position eccentric by a distance “e” from the rotation center O ₂ (see FIG. 5). The tip of the upper electrode guide 20 is provided so as to protrude downward through a hole provided in the bottom of the eccentric rotating shaft 19.

Further, a flange 21 concentric with the rotation center O ₂ is provided at the upper part of the eccentric rotation shaft 19, and a ring 23 fitted to the outer periphery of the flange 21 is a recess provided in the flange 25 at the upper part of the drive shaft 9. 27 is rotatably engaged.

  The ring 23 is pressed and fixed to the flange 21 by a C-shaped retaining ring 33 through a wave washer 29 and a washer 31.

  The upper electrode guide 20 is detachably pressed from the nut member 37 to the bottom of the eccentric rotary shaft 19 with a cylindrical intermediate member 35a, 35b through which the electrode 5 can pass.

  Further, the nut member 37 is provided with a funnel 39 for preventing a water jet when the electrode 5 is inserted and guided into a lower electrode guide 53 to be described later from being scattered and for guiding it downward.

  A knob 41 knurled on the outer periphery is attached to the upper end of the eccentric rotating shaft 19.

  The rotation of the flange 25 of the drive shaft 9 and the ring 23 above the eccentric rotation shaft 19 is regulated by a plurality of set screws 43. Therefore, in this state, the eccentric rotation shaft 19 and the upper electrode guide 20 rotate integrally.

When it is necessary to adjust the amount of eccentricity of the upper electrode guide 20 from the processing center O _1, by loosening the set screw 43 and rotating the eccentric rotation shaft 19 with respect to the drive shaft 9 as appropriate, The amount of eccentricity can be adjusted in the range of 0 to 2e (see FIG. 5).

  A scale 45 indicating the amount of eccentricity is provided on the outer periphery of the flange 25 so that the amount of eccentricity can be visually recognized. A reference line 47 for zero adjustment of the amount of eccentricity is provided on the outer periphery of the ring 23, and By providing a viewing window 49 for viewing the line 47, the set eccentricity can be confirmed.

  A lower electrode guide holder 51 is attached to the lower surface of the housing 3 with bolts 52. The lower electrode guide holder 51 has a holding portion 51 a that is opened in a concave shape downward to hold the lower electrode guide 53, and the holding portion 51 a is inserted into the lower end portion of the cylindrical drive shaft 9. It is fixed to the housing 3.

The holding portion 51 a of the lower electrode guide holder 51 is provided with a lower electrode guide 53 coaxial with the rotation center 17 (O ₁ ) of the drive shaft 9 so as to be attachable / detachable with a fixing screw 55.

  2 and 4 together, a turbine 57 for rotationally driving the drive shaft 9 is provided at the lower portion of the cylindrical drive shaft 9 extending to the lower portion of the housing 3. As a means for fixing the turbine 57 to the drive shaft 9, for example, a key groove is provided in the drive shaft 9, and a key that engages with the key groove is provided in the turbine 57 to restrict relative rotation, and the housing 3, a snap ring 58 that supports the lower surface of the turbine 57 may be provided.

  Further, as shown in FIG. 4, the housing 3 is provided with a supply path 59 for supplying high-pressure machining fluid (for example, water or pure water) from a machining fluid supply pump (not shown) to the turbine 57.

  As shown in FIG. 3, the lower electrode guide holder 51 is provided with a plurality of drain holes 61 along the vicinity of the outer periphery of the turbine 57 from which the machining fluid that has lost pressure by rotating the turbine 57 falls. In addition, in the high-pressure machining fluid supplied to the supply path 59, an escape hole 63 is provided at the end portion of the supply path 59 for allowing excess high-pressure machining liquid to escape to rotate the turbine 57.

According to the fine hole electric discharge machining apparatus having the above configuration, the amount of eccentricity of the upper electrode guide 20 from the rotation center (machining center O ₁ ) 17 of the drive shaft 9 is adjusted, and then the lower electrode guide 53 is placed near the upper surface of the workpiece W. When the electric discharge machining is performed while rotating the upper electrode guide 20 by rotating the turbine 57 with the high-pressure machining fluid from the machining fluid supply pump and rotating the upper electrode guide 20, the hole is directed from the machining hole inlet to the outlet. A desired tapered hole having a large diameter can be processed.

  As described above, according to the narrow hole electric discharge machining apparatus of the present invention, the turning drive means of the upper electrode guide 20 is driven by the turbine using the high-pressure machining liquid used in the electric discharge machining. The drive does not require the necessary waterproofing mechanism. Therefore, it is possible to provide a compact thin hole electric discharge machining apparatus with reduced manufacturing costs.

DESCRIPTION OF SYMBOLS 1 Lower electrode guide apparatus 3 Housing 4 Support plate 5 Electrode 7 Electrode holder 9 Drive shaft 11 (a, b) Bearing 13 Spacer 15 C-type retaining ring 17 Rotation center of drive shaft 19 Eccentric rotation shaft 20 Upper electrode guide 21 Flange 23 Ring 25 Drive shaft 9 flange 27 Recess 29 Wave washer 31 Washer 33 C type retaining ring 35 (a, b) Intermediate member 37 Nut member 39 Funnel 41 Knob 43 Set screw 45 Scale 47 Reference line 49 Viewing window 51 Lower electrode guide holder 51a Holding portion 53 Lower electrode guide 55 Fixing screw 57 Turbine 58 Snap ring 59 Supply path 61 Drain hole 63 Relief hole O ₁ Rotation center of drive shaft O ₂ Rotation center of eccentric rotation shaft W Workpiece

Claims (3)

A narrow hole electric discharge machining apparatus for machining a tapered hole whose diameter increases from the upper surface to the lower surface of the workpiece,
An electrode holder that is rotatable by holding the upper end of a rod-like or pipe-like electrode on a spindle that can be positioned in the vertical direction; and
A housing disposed below the electrode holder;
A lower electrode guide provided on the lower surface of the housing and coaxial with the processing center ;
Oite between the lower electrode guide and the electrode holder, with respect to the housing, and an upper electrode guide rotatably disposed at a position eccentric from the processing center via a bearing,
A turning drive means provided below the bearing for turning the upper electrode guide around the processing center ;
With
The small hole electric discharge machining apparatus , wherein the turning drive means is a turbine that is rotationally driven by a high-pressure machining fluid . The fine hole electric discharge machining apparatus according to claim 1, further comprising a hole for dropping a machining fluid obtained by rotating the turbine . Small hole electric discharge machining apparatus before Symbol claim 1 or claim 2, wherein the having the eccentricity adjusting mechanism for adjusting the eccentricity of the upper electrode guide.

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