JPH0343122A - Bent hole processing device - Google Patents

Abstract

PURPOSE:To process a deep bent hole by providing a holder insertable in a processing hole, axes slidably supported for the holder, a driving means having an actuator, and a means clamping the holder and an electrode tool. CONSTITUTION:Driving parts 21a, 21b, and 21c are composed of voltage actuators 3a, 3b, and 3c, elastic bodies 2a and 2b, and axes 4. The elastic bodies 2a and 2b are pressed to proceed solidly with the axes 4 in a holder 1 or only the elastic bodies 2a and 26 proceed by relative movement to the axes 4 by the variation of voltage applied respectively to the actuators 3a, 3b, and 3c. By this the axes 4 successively proceeds in the holder 1, and an electrode 6a diggingly proceeds in the tip of a processing hole 8 while an electrode tool 6 is proceeding via spherical hearings 5a and 5b. Next when driving means 21a, 21b, and 21c are actuated with the proceeding of the electrode tool 6 stopped, and with the electrode tool 6 clamped and the holder 1 unclamped to the processing hole 8, the holder 1 moves in a direction approaching the electrode tool 1.

Description

[Detailed description of the invention] Industrial application field> The present invention relates to a curved hole machining device that enables the machining of a hole having an arbitrary curvature in a workpiece, even a deep hole. It is suitable for machining coolant passages such as.

<Prior art> When designing a plastic mold, it is important to consider the thermal deformation of the mold during plastic molding and the cooling effect of the molded plastic. The technology involved is the know-how for designing high-precision plastic molds and achieving high-precision plastic molding using these molds.

Therefore, conventionally, in order to reduce this thermal deformation and improve the cooling effect of the molded plastic, cooling holes through which a cooling liquid is forced have been provided in the mold. The cooling liquid in this cooling hole prevents thermal deformation of the mold, and also removes the heat held by the molding plastic injected into the mold in a molten state, rapidly cooling and solidifying the plastic, increasing molding efficiency. It is intended to improve That is, the cooling holes are for cooling the mold and uniformly cooling the plastic molded product to obtain a highly accurate plastic molded product with little distortion.

Conventionally, cooling holes are generally formed in the vicinity of the plastic molding surface in a mold, and are often formed into straight holes by drilling or curved holes by combining straight holes by drilling.

Therefore, if it is possible to machine a curved hole with a flexible curvature inside the mold near the plastic molding surface, it will be possible to
The degree of freedom in designing the cooling holes, which are cooling fluid passages, is increased, making it possible to reduce thermal deformation of the mold and allowing more rapid and uniform cooling of the plastic molded product.

<Problems to be Solved by the Invention> Since cooling holes in conventional plastic molding molds are usually processed by drilling, flexible curved holes cannot be formed, and only straight holes can be formed. Further, in hole machining by electric discharge machining, it is only possible to machine a shallow curved hole near the mold surface using a curved electrode, and it is difficult to machine a curved hole at a deep position within the mold.

Therefore, it is not possible to machine a cooling hole with a curved hole shape deep within the mold, making it impossible to effectively prevent thermal deformation of the mold and cooling the plastic, making it difficult to design a mold with high precision. However, it is also difficult to improve the shape accuracy of the molded plastic.

Ku section! ! Means for Solving Problem 1〉 The curved hole machining device according to the first aspect of the present invention includes a machining tool for machining a hole, and a machining tool that is assembled to the machining tool and fixed to the inner wall of the machined hole. a holder located on the rear end side of the processing tool and capable of being inserted into the hole; a plurality of shafts slidably supported in the front and rear directions with respect to the holder; a plurality of universal joints that respectively connect the rear end side of the machining tool and the front end of the shaft; multiple drive units that can freely change the direction;
The present invention is characterized by comprising holder clamping means that is assembled to the holder and operates alternately with the tool clamping means to fix the holder to the inner wall of the hole.

A curved hole machining device according to a second aspect of the present invention includes a machining tool for machining a hole, a tool clamping means that is assembled to the machining tool and can fix the machining tool to the inner wall of the machined hole, and a holder located on the rear i side of the machining tool and capable of being inserted into the hole; a plurality of shafts slidably supported in the front and rear directions with respect to the holder; and a rear end side of the machining tool; a plurality of universal joints that respectively connect the front ends of the shafts, and a plurality of universal joints that independently feed and drive the plurality of shafts in the front-rear direction and can freely change the relative orientation of the machining tool with respect to the holder. a drive unit,
holder clamping means that is assembled into the holder and can operate alternately with the tool clamping means to fix the holder to the inner wall of the hole; an elastic body that fits loosely against the shaft when compressive force is applied and tightly fits against the shaft when no compressive force is applied; A pair capable of compressing the elastic body in the front-rear direction and sliding the elastic body in the front-rear direction in an integrally fitted state with the shaft or in a loosely fitted state separated from the shaft by a potential difference of an applied voltage. The present invention is characterized by comprising: piezoelectric actuators; and control means for controlling voltage applied to these piezoelectric actuators to select sliding in the fitted state and sliding in the loosely fitted state.

Function> With the holder fixed in the hole by the holder clamping means, by feeding and driving each of the plurality of axes supported by the holder with the drive section, the processing tool is fed through the universal joint. While moving forward, the machining tool performs hole machining. Next, with the machining tool fixed in the hole by the tool clamping means, each of the plurality of axes is fed and driven in the opposite direction to the feed drive using the drive unit, so that the holder moves inside the hole via the universal joint. Advance.

By repeating the above operations, the curved hole machining device moves forward within the machined hole while machining the hole.

At this time, since the shaft and the machining tool are connected via the universal joint, the relative orientation of the machining tool with respect to the holder can be freely changed by the drive unit, and even curved holes can be machined. The curved hole machining device advances along this hole.

Note that the shaft feeding drive by this drive unit is performed by repeating the following operations.

When voltages having a voltage difference are applied to a pair of piezoelectric actuators by the control means, the elastic body moves within the holder due to pressure from the piezoelectric actuator on the high voltage side, and as a result, the shaft fitted with the elastic body moves inside the holder. It slides as one.

Next, when a high voltage with a voltage difference is applied to the pair of piezoelectric actuators by the same control means, the elastic body is compressed by the piezoelectric actuator, and the elastic body and the shaft fit loosely, and the piezoelectric actuator on the high voltage side Only the elastic body moves within the holder when pressed.

Embodiment An embodiment of the curved hole machining apparatus according to the present invention will be described in detail with reference to FIGS. 1 to 7.

FIG. 1 shows a cross-sectional view of machining a curved hole in a mold using the curved hole machining device of the present invention. A boulder 1 is located in the machined hole 8.

Three shafts 4 that slidably pass through the holder 1 over the front and rear ends of the holder 1 are attached to the holder 1 in parallel to each other at equidistant positions on the circumference.

A cylindrical elastic body 2a made of S is provided at the portion of the shaft 4 located on the front end side of the holder 1, and the elastic body 2a is located opposite to the elastic body 2a through a sliding gap and sandwiching the elastic body 2a. A pair of piezoelectric actuators 3a and 3b are fitted into each other. Further, in the portion of the shaft 4 located on the rear end side of the holder 1, there is similarly a cylindrical steel elastic body 2b, and a piezoelectric actuator 3C that comes into contact with the rear end side of this elastic body 2b.
are fitted respectively.

FIGS. 4 and 5 are enlarged and detailed views of the elastic bodies 2a and 2b. A center hole 17 is provided on the inner peripheral side of the elastic bodies 2a, 2b, and a small hole 1 having an inner diameter d smaller than the outer diameter of the shaft 4 is located in the axial center of the center hole 17.
One perforated step 12 is provided.

Further, in the elastic bodies 2a and 2b, as shown in FIG. 4, grooves 13 are formed, respectively, to form an elastically deformable portion 15a extending from the upper left end toward the lower center and an elastically deformable portion 15b extending from the upper right end toward the lower center. a, 13 b, 13 a, 13
d, a groove 13e that separates the upper half of the center portion into left and right sides, and a groove 1113f that separates the stepped portion 12 vertically, are formed by, for example, wire-cut electric discharge machining.

Therefore, normally the shaft 4 and the elastic bodies 2m, 2b are tightly fitted, but when a compressive force is applied to the ends 14a, 14b of the elastic bodies 2a, 2b, the center lower side in FIG. The located chuck portion 16 moves vertically in FIG. 4, and the shaft 4 and the elastic bodies 2m, 2b are loosely fitted.

On the other hand, the piezoelectric actuators 3a and 3b.

3c is fitted with the shaft 4 in a loosely fitted state, and is made of barium titanate or the like which generates strain in the axial direction of the shaft 4 in proportion to the applied voltage when a voltage is applied. has been done.

Therefore, each piezoelectric actuator 3 m.

3b and 3c are piezoelectric actuators 3a and 3b that freely apply voltage from an external power source (not shown).

An actuator control means is connected via wiring (not shown) so as to apply a voltage to 3C.

That is, these elastic bodies 2a and piezoelectric actuators 3
a, 3b, etc. constitute a driving section, and the elastic body 2b, piezoelectric actuator 30, etc. constitute a fixed section, and these driving section, fixed section, and shaft 4 constitute a set of driving means 21a.

From the above, the pair of piezoelectric actuators 3a.

When no voltage is applied to the piezoelectric actuators 3m and 3b, both ends 14a and 1 of the elastic body 2a sandwiched between the piezoelectric actuators 3m and 3b
No compressive force is applied to piezoelectric actuator 4b, and piezoelectric actuator 3a, 3
b and the shaft 4 are in a clamped state in which they are tightly fitted. Therefore, the elastic body 2a and the shaft 4 can slide integrally with respect to the holder 1.

When a voltage is applied to both the pair of piezoelectric actuators 3m and 3b, both piezoelectric actuators 3a and 3b extend in the axial direction of the shaft 4 by an amount greater than the gap between the elastic body 2a and the piezoelectric actuators 3a and 31). Therefore, the elastic body 2a
The piezoelectric actuators 3a and 3b come into contact with each other, and compressive force is applied to both ends 14a and 14b of the elastic body 2a. Therefore, due to this compressive force, the upper half of the central part of the separated elastic body 2a shown in FIG.
5a and 15b bend upward and downward in FIG. 4, the chuck portion 16 is displaced and the stepped portion 12 releases the shaft 4, resulting in an unclamped state in which the shaft 4 and the elastic body 2a fit loosely. Therefore, the elastic body 2a and the shaft 4 can be slid relative to each other.

A state where voltage is applied only to either one of the pair of piezoelectric actuators 3a and 3b, for example, the piezoelectric actuator 3
When voltage is applied only to b, this piezoelectric actuator 3
Since only b extends in the axial direction, the shaft 4 together with the elastic body 2a is slid toward the piezoelectric actuator 3a side, which is the front end side of the holder 1, by the gap needle between the elastic body 2a and the piezoelectric actuator 3a.

When different voltages are applied to the piezoelectric actuators 3m and 3b, for example, if the voltage of the piezoelectric actuator 3a is set high and the voltage of the piezoelectric actuator 3b is set low, the elastic body 2a is pressed and the shaft 4 and the elastic body 2a are loosely fitted, and only the elastic body 2a moves toward the rear end of the holder 1.

Furthermore, when no voltage is applied to the piezoelectric actuator 3C located on the rear end side of the holder 1, the elastic body 2b and the shaft 4
are tightly fitted, and the shaft 4 is connected to the holder 1 via the elastic body 2b.
When a voltage is applied to the piezoelectric actuator 3C, the elastic body 2b is pressed and the elastic body 2b and the shaft 4 are loosely fitted, resulting in an unclamped state where the shaft 4 is not gripped by the holder 1. Become.

6 and 7 show the piezoelectric actuator 3 shown in FIG. 1.
3b, an elastic body 2a, a piezoelectric actuator 3c, an elastic body 2b, a shaft 4, and the like. Here, FIG. 6 schematically shows the operating principle, and Va is the piezoelectric actuator 3.
2b is the applied voltage of the piezoelectric actuator 3b, and VC is the applied voltage of the piezoelectric actuator 3C.

FIG. 7 shows the applied voltages in the operating states (1), (2), (2) and (2) of FIG. 6, respectively. Therefore, the operating state is as follows.

In the operating state ■, the piezoelectric actuators 3a, 3b
The applied voltage is low, the elastic body 2a is in a clamped state,
The voltage applied to the piezoelectric actuator 3c is high, and the elastic body 2b
is in an unclamped state.

In the operating state ■, the voltage applied to the piezoelectric actuator 3c is high and the elastic body 2b is in the reciprocating state;
The voltage applied to the piezoelectric actuator 3a decreases, the voltage applied to the piezoelectric actuator 3b increases, and the elastic body 2a moves in the clamped state, resulting in the shaft 4 moving in the direction of arrow Z.

In the operating state ■, the piezoelectric actuators 3a, 3b
The voltage applied to the piezoelectric actuator 3C increases and the elastic body 2a becomes unclamped, and the voltage applied to the piezoelectric actuator 3C decreases and the elastic body 2b becomes clamped.

In the operating state (2), the voltage applied to the piezoelectric actuator 3a further increases, the voltage applied to the piezoelectric actuator 3b decreases, and the elastic body 2a retreats while remaining in the unclamped state.During this period, the elastic body 2b remains in the clamped state. Ru.

In this way, by repeating the operating state ■→■pass■→■→■, the shaft 4 is driven to be fed minutely repeatedly.

The holder 1 is further provided with two sets of drive means 21b and 21c having the same configuration as the drive means 21a on each shaft 4. Therefore, these three sets of drive means 21a
, 21 b, and 21 c are to be installed in the holder 1.

On the front end side of the holder, an electrode tool 6 for electrical discharge machining, which is a machining tool, is located in the machining hole 8, facing the holder 1. An electrode 6a is located for this purpose. The electrode 6a has a machining fluid ejection hole (not shown) drilled on the tip side for spouting machining fluid supplied from a machining fluid supply source (not shown), and a current supply line for connecting to an external m source (not shown). connected.

Three spherical bearings 5b, which are universal joints, are provided on the rear end side of the electrode tool 6, facing the three shafts 4, and spherical bearings 5a are also provided at the tips of the shafts 4, respectively. The spherical bearing 5b and the spherical bearing 5a are connected by connecting pins 22, respectively.

Further, as shown in FIG. 2 showing the cross section AA, the electrode tool 6 includes three rotatable ceramic ball bushes 9a and 9b, respectively.

9C is installed at a position that roughly divides the outer periphery of the 1RfIi tool 6 into thirds, and allows the electrode tool 6 to move while being guided within the machined hole 8.

For this purpose, three sets of drive means 21a, 21b are provided.

By driving the respective shafts 21c and repeatedly feeding the respective shafts 4, the electrode tool 6 relative to the holder 1 is moved.
The position and posture of the connecting bottle 22 and the spherical bearing 5a can be adjusted freely.
, 5b. That is, the electrode tool 6 is
While spouting machining fluid and performing electrical discharge machining with the electric fIi6a, the ball bushes 9a and 9b.

It is supported in the machined hole 8 at 9c, and moves forward in the machined hole 8 in an arbitrary direction and at an arbitrary curvature by micro-repetitive feeding of the drive means 21a, 2lb, and 21c.

Furthermore, a pair of rotatable ball bushes 23a are provided on the outer periphery of the holder 1 facing the machined hole 8.

23b is provided. Furthermore, on the outer circumferences of the electrode tool 6 and the holder 1 facing the machined holes 8 of the electrode tool 6 and the holder 1, pistons 7a and 7b each having a hemispherical tip, which is a clamping means, are provided for the ga electrode tool. With the holder 1 as a cylinder, three pieces are installed on the electric fence tool 6 and two pieces are installed on the holder 1 radially with respect to the respective central axes.

The electrode tool 6 and holder 1 further include pistons 7a and 7.
Hydraulic piping (not shown) is provided to press the proximal end sides of b.

Therefore, when hydraulic oil is supplied through hydraulic piping (not shown), the pistons 7m and 7b protrude from the machined hole 8.
The electrode tool 6 and the holder 1 are respectively fixed to the machined hole 8 in an electrode clamp state and a holder clamp state. If hydraulic oil is not supplied, the piston 7a
, 7b and the machined hole 8 do not come into contact with each other, resulting in an electrode unclamped state and a holder unclamped state in which the 'R electrode tool and the holder 1 can move freely within the machined hole 8, respectively.

Incidentally, the outer peripheral surface of the holder 1 has a plurality of grooves 10a, 10b, 10c toward the front and rear ends of the holder 1.

10e and 10f are provided, and current supply lines for electrical discharge machining (not shown) and piezoelectric actuators 3a and 3 are provided in the groove.
Wiring for applying voltage to the pistons 7a, 7b, etc., hydraulic piping to the pistons 7a, 7b, etc. are provided.

From the above, the driving means 21a shown in FIG.

21b and 21c expand and contract the distance between the holder l and the electrode tool 6 connected to the holder 1, and electrical discharge machining is performed so that the electrode 6a further digs into the machined hole 8 in any direction and with any curvature, The curved hole machining device moves forward within the machined hole 8.

That is, by repeating the following operation cycle (1) → (2) → (3) → (4) with the tool 6 and the holder 1, the device performs an inchworm movement within the machined hole 8. It is said that

(1) In the initial state, it is assumed that the holder 1 is in a holder clamp state with respect to the machined hole 8, and the electrode tool 6 is in an electrode unclamped state with respect to the machined hole 8.

(2) 3 consisting of piezoelectric actuators 3a, 3b, elastic body 2a, piezoelectric actuator 3c, elastic body 2b, and shaft 4
By controlling the number of times each of the driving means 21a, 21b, 21c in the set is operated, the electrode tool 6 changes its position and attitude with respect to the holder 1 while being guided in the machined hole 8 by the ball bushes 9a, 9b, 9c. and move.

(3) Next, the movement of the electrode tool 6 is temporarily stopped, and the electrode tool 6 is brought into an electrode clamp state with respect to the machined hole 8. In this case, since the electrode tool 6 is guided in the machining hole 8 by the ball bushes 9a, 9b, and 9c, the position and posture immediately after machining are maintained. At the same time, the holder 1 is brought into a holder unclamped state with respect to the machined hole 8.

(4) Three sets of driving means 21 a, 21 b, 21
By the operation c, the machined hole 8 is moved so that the holder 1 approaches the electrode tool 6.

In this embodiment, piezoelectric actuators 3a and 3b.

Although barium titanate is used as the material for 3C, other well-known ceramic piezoelectric materials may be used, polymeric materials such as borif, vinylidene dioxide (PVDF), or composite materials of ceramic materials and polymeric materials may be used. . moreover,
Other known materials having piezoelectric effects may also be used.

Furthermore, the same effect can be obtained by using an actuator that drives the shaft 4 by other well-known driving means such as magnetostriction, hydraulic pressure, pneumatic pressure, etc. instead of the piezoelectric actuator.

In this embodiment, the elastic bodies 2a and 2b are formed into grooves 13a.

13 b, 13 c, 13 d, 13 e, 1
Although the elastic body is made of a steel column with 3 f engraved, other well-known elastic materials that can form a similar structure may also be used.
Any material having a similar function may be used regardless of the shape, such as other well-known elastic materials such as rubber.

Although the electrode i6a is used as an m-pole for electrical discharge machining, the same effect can be obtained as an electrode for electrolytic machining. Furthermore, the same effect can be obtained by using other well-known drilling tools instead of the electrode 6a.

Although the clamping and unclamping means in the electrode tool 6 and the machined hole 8 of the holder 1 are hydraulic in this embodiment, other well-known hydraulic, pneumatic, or electric means may be used.

<Effects of the Invention> According to the curved hole machining device of the present invention, the curved hole can be machined while moving the hole machined by the device itself by remote control from the outside, so deep curved holes can be machined freely.

As a result, for example, the cooling hole of the mold can be bent to any desired curvature, which increases the effect of suppressing thermal deformation of the mold and increases the cooling effect of the plastic molded product, making it possible to stably perform high-precision plastic molding. I can do it.

Therefore, it becomes easy to design and manufacture a mold, and also facilitates plastic molding, thereby improving productivity and quality.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of a curved hole machining device according to the present invention, FIG. 2 is a view taken along the line A-A in FIG. 1, and FIG. 4 is a side view of the elastic body of the bent hole processing device according to the present invention, FIG. 5 is a view taken along the line C-C in FIG. 4, and FIG.
FIG. 7 is an explanatory diagram of the operation of the driving means, and FIG. 7 is an explanatory diagram showing the voltage applied to the piezoelectric actuator in the operating state of FIG. 6. In the drawings, 1 is a holder, 2a, 2b are elastic bodies, 3a, 3b, 3c are piezoelectric actuators, 4 is a shaft, 5a, 5b are spherical bearings, 6 is an electrode tool, 7a, 7b are pistons, 8 is processing It's a hole. Patent applicant Mitsubishi Heavy Industries, Ltd. Agent

Claims (2)

[Claims] (1) A processing tool for drilling a hole, a tool clamping means that is assembled to the processing tool and capable of fixing the processing tool to the inner wall of the processed hole, and a tool clamping means located on the rear end side of the processing tool. and a holder that can be inserted into the hole, a plurality of shafts that are slidably supported in the front and rear directions with respect to the holder, and a rear end side of the processing tool and a front end of the shafts are respectively connected. a plurality of universal joints that are assembled to the holder; A curved hole machining device comprising: a holder clamping means which is configured to clamp the holder to the inner wall of the hole by alternately operating with the tool clamping means to fix the holder to the inner wall of the hole. (2) a processing tool for drilling a hole; a tool clamping means that is assembled to the processing tool and capable of fixing the processing tool to the inner wall of the processed hole; and a tool clamping means located on the rear end side of the processing tool. and a holder that can be inserted into the hole, a plurality of shafts that are slidably supported in the front and rear directions with respect to the holder, and a rear end side of the processing tool and a front end of the shafts are respectively connected. a plurality of universal joints that are assembled to the holder; and a holder clamping means that can be operated alternately with the tool clamping means to fix the holder to the inner wall of the hole, and the driving section is incorporated in the holder and acts on the compressive force in the longitudinal direction. an elastic body that fits loosely against the shaft and tightly fits against the shaft when no compressive force is applied; a pair of piezoelectric actuators that can be compressed in the longitudinal direction and that can slide the elastic body in the longitudinal direction in a fitted state integrally with the shaft or in a loosely fitted state separated from the shaft by a potential difference of applied voltages; A curved hole machining device comprising: a control means for controlling voltages applied to these piezoelectric actuators to select sliding in the fitted state and sliding in the loosely fitted state.