JPH0763916B2 - Machining center - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a machining center that performs various types of machining on a workpiece automatically and at high speed.

[Conventional technology]

In recent years, from the viewpoint of rationalization and unmanned production line, a machining center (multi-function machine tool) capable of automatically and highly efficiently performing various machining processes such as milling, tap cutting, and boring has been widely used. The machining center usually has a positioning function of automatically positioning a workpiece, and a machining function of performing necessary processing such as milling, tap cutting, and boring on a processing portion of a target workpiece. A wide variety of processing tools for performing the necessary processing are connected and fixed to the tool holder and built-in.
Necessary tools are automatically selected from them, taken out together with the tool holder, and attached to the lower end of the spider itself to perform machining.

FIG. 10 shows a state in which a machining tool is mounted together with a tool holder on such a machining center. The figure is a vertical cross-sectional view of the periphery of a machining spindle of a machining center. In the figure, 1 is a spindle for giving a rotary motion to a machining tool when machining a workpiece, 2 is a tool holder mounted on the lower end of the spindle 1, and 3 is a machining tool connected and fixed to the tip of the tool holder 2. Is. The tool holder 2 will be described in detail. The tool holder 2 has a truncated cone-shaped fitting portion 4 that fits into the tapered inner wall 3 near the lower end of the spindle, and the center of the upper end surface of the fitting portion 4. A gripped portion 6 that projects in a bolt shape and engages with the chuck portion 5 in the spindle, and an engagement that engages with a tool detaching arm (not shown) of the machining center formed at the bottom of the fitting portion 4 The arm gripping portion 8 having the groove portion 7 and the tool connecting shaft 9 extending downward from the center of the lower end surface of the arm gripping portion 8 are provided. Then, the machining tool 3a is inserted into the lower end of the tool connecting shaft 9 of the tool holder 2 and is connected and fixed by a fixing screw 10.

In such a state, the machining work of the machining center is performed as follows. That is, first, a workpiece is placed on a workpiece placing table (not shown) provided below the spindle 1. The table is adapted to slide in the XY directions in accordance with a pre-input instruction, and positions the work at the machining start point (origin) of the work. Then, the spindle 1 is rotationally driven to rotate the machining tool 3a together with the tool holder 2, and at the same time, the table is raised (in some cases, the spindle 1 side is lowered) so that the cutting edge of the machining tool 3a is covered with the workpiece. It presses against the machining area and starts machining the workpiece. As a result, the pressure contact position (processing point) is caused by the movement of the table or the movement of the spindle 1 in accordance with the instruction inputted in advance.
Changes from moment to moment and a constant machining shape is imparted to the workpiece. In this way, a series of machining work is completed,
The pressure contact between 3a and the workpiece is released, and the processed workpiece is taken out from the table. When performing the same machining on multiple workpieces, the machined workpieces are taken out of the table, new workpieces are supplied to the table at the same time, and continuous machining is performed by repeating the above series of operations. Is done automatically.

By the way, even in automatic machining by such a machining center, it is necessary to inject water such as cutting fluid or grinding fluid as in the case of normal machining work.Therefore, a water injection nozzle for discharging cutting fluid or grinding fluid is provided in the machining center. ing.

[Problems to be solved by the invention]

However, even though the machining direction of the tool with respect to the workpiece is regulated by the relative positional relationship between the table on which the workpiece is placed and the spindle as described above, the pouring of cutting fluid or grinding fluid is not possible. Usually, it is performed from a water injection nozzle fixed to a part completely unrelated to the movement of the table and spindle in the machining center, and it is independent of the movement of the table, that is, the machining direction of the tool with respect to the workpiece. Is the reality. Therefore, in spite of the fact that it is desirable to cool the contact point where the blade of the tool enters the workpiece, which is the point that generates the most heat during cutting, grinding, etc. The heat generated during machining cannot be adequately cooled and cutting chips cannot be properly removed, resulting in severe tool damage.

Therefore, as shown in FIG. 11, it is assumed that the water injection nozzle can be extended and the direction can be changed with fingers, and a person can appropriately move the nozzle 50 while observing the processing state. However, the unmanned work, which is a characteristic of machining centers, is impaired. Therefore, it is desired to realize a machining center equipped with a mechanism such that water injection is always aimed at the heat generation point, but it is not yet practically used.

The present invention has been made in view of such circumstances, and an object thereof is to provide a machining center having a function such that water injection in a machining center is aimed at a contact point where a blade of a tool constantly enters a workpiece. It is what

[Means for solving problems]

In order to achieve the above-mentioned object, the machining center of the present invention drives a spindle in which a tool holder to which a water injection nozzle and a holder to which a water injection pipe is attached are rotatably fitted can be fitted into the lower end of the spindle. A machining center provided with a spindle drive means, the connecting means being detachably fitted to the water injection pipe attached to the holder of the tool holder, and connecting and integrating with the water injection pipe at the time of fitting, and the connecting means. A supply means for supplying a water injection liquid to the holder, an auxiliary drive means for driving the holder through the connecting means, and a water injection port of a water injection nozzle attached to the holder at the time of processing so that the water injection port of the holder faces the processing point. And a control means for controlling the drive by the auxiliary drive means.

[Action]

That is, in order to add a function to the machining center such that the water injection in the machining center is always aimed at the contact point where the blade of the tool enters the workpiece, the inventor of the present invention controls the water injection nozzle itself with a constant control. I thought that it had to be linked with the movement of the work under. Therefore, as a result of investigating whether to attach the water injection nozzle that is linked to the movement of the work piece to the machining center body or to the tool holder equipped in the machining center, when the water injection nozzle is attached to the machining center body, drive control and water injection are performed. Although it is easy to form a path, etc., it is difficult to accurately determine the water injection direction due to the distance between the machining point and the water injection nozzle mounting position being too long. It is selected and set on the spindle of the main body of the machining center, but the height of the machining point changes depending on the size and type of tool, so the height of the water injection nozzle must be adjusted each time. It turned out to be. On the other hand, if a water injection nozzle is attached to the tool holder and drive control and water injection are performed from the machining center body side, it is necessary to connect the machining center body side and the water injection nozzle when the tool holder is attached. Although necessary, it is not necessary to adjust the height of the water injection nozzle each time the tool is changed, and accurate water injection can always be performed toward the machining point. From such a standpoint, a series of researches were conducted on mounting the water injection nozzle on the tool holder side. As a result, a holder for preventing water splashing is attached to the tool connecting shaft of the tool holder attached to the machining center, a water injection nozzle is attached to this holder, and the holder protrudes from the holder and is detachably fitted to the machining center body side. If you install a water injection pipe and rotate or stop the holder via the water injection pipe so that it interlocks with the movement of the tool with respect to the workpiece, and perform water injection while directing the water injection port of the water injection nozzle toward the processing point, They have found that they have achieved their intended purpose and have arrived at this invention.

〔Example〕

Next, the present invention will be described in detail based on examples.

FIG. 1 shows an embodiment of the machining center of the present invention, in which the tool holder 14 is mounted.

This machining center has the same basic structure as a conventional machining center (see FIG. 10), but a special tool holder 14 described later is mounted and a part thereof is modified to drive and control it. That is, this machining center comprises a ring gear 30 that rotates along the circumference of the lower end surface of the outer cylinder 1a of the spindle 1, a worm gear 31 that meshes with the ring gear 30 and drives the ring gear 30 in the circumferential direction, and an intermittent worm gear 31. The auxiliary drive means including a pulse motor 32 such as a stepping motor that gives various rotations is provided, and the ring gear 30 is rotated completely independently of the rotary drive system of the spindle 1. Reference numeral 30a is a guide ring that rotatably holds the ring gear 30 on the lower end surface of the outer cylinder 1a of the spindle 1, and a portion corresponding to a portion where the ring gear 30 and the worm gear 31 engage with each other is cut out. A connection pipe 33 is attached to one portion of the lower end surface of the ring gear 30, and a water injection tube (not shown) is in communication therewith. Spindle 1 in this machining center
A tool holder 14 having a special structure including a holder 16, a water injection nozzle 17 attached and fixed to the holder 16, and a water injection pipe 18 communicating with the water injection nozzle 17 is inserted and fixed therein. In this case, the holder 16 is adapted not to be affected by the rotation of the tool holder 14 itself, and the connecting pipe 33
Via the water injection pipe 18 connected to the ring gear
It is designed to rotate with the rotation of 30. As a result, the directing direction of the nozzle port of the water injection nozzle 17 also changes. In this machining center, the nozzle port of the water injection nozzle 17 is automatically directed to a processing point, and the water injection liquid is automatically projected to the processing point. Therefore, the pulse motor 32 is connected to a control means (not shown) for controlling the drive of the ring gear 30 based on the output.
As the control means, for example, a reading means for reading the position of the processing point and outputting a signal, and a holder 16 such that the water injection port of the water injection nozzle 17 faces the processing point based on the output signal from the reading means. An example is a combination of an arithmetic processing unit that calculates a rotation angle and outputs the rotation angle, and an energization unit that energizes the pulse motor 32 based on the output. In such a combination, the reading means reads, for example, the movement of the workpiece placement table that moves the workpiece in order to appropriately perform machining, using X and Y coordinates, and adjusts to the movement of the workpiece placement table. This utilizes the characteristic of a machining center that a machining point moves. In the above reading, the position of the table of the machining start point is the origin (0,0), the position after t ₁ seconds is (x ₁ , y ₁ ), the position after t ₂ seconds is (x ₂ , y ₂ ) ... It is performed by continuously reading as. The data signal obtained by the reading means is input to arithmetic processing means such as a computer. The arithmetic processing means receives Δt when receiving the data signal.
From the displacement of the table in
The rotation angle of is calculated and output. However, the calculation formula for calculating the rotation angle of the holder 16 from the displacement of the table differs depending on the shape of the workpiece to be ground.Therefore, the calculation formula should be input in advance at the presetting stage of the machining center, or already input. It is necessary to select from multiple arithmetic expressions. Then, a signal is sent to the auxiliary drive means based on the output from the arithmetic processing means, and the ring gear 30 is rotated by a required angle. Here, the special tool holder 14 will be described in detail. The tool holder 14 was developed in accordance with the modification of the machining center, and is constructed as shown in FIG. That is, the tool holder 14 has a truncated cone-shaped fitting portion 4 that fits into the tapered inner wall 3 near the lower end of the spindle 1 and a bolt-like projection from the center of the upper end surface of the fitting portion 4. An arm having a gripped portion 6 that engages with the chuck portion 5 in the spindle 1 and an engagement groove portion 7 that engages with a tool attaching / detaching arm (not shown) of the machining center formed at the bottom of the fitting portion 4. It has a gripped portion 8 and a tool connecting shaft 9 extending downward from the center of the lower end surface of the arm gripped portion 8. Reference numeral 16 denotes a holder that is attached to the tool connecting shaft 9 via a ball bearing 15 and can hold a stationary state without being affected by the rotation of the tool connecting shaft 9. The holder 16 has a shape of a heavenly cylinder in which a part of the side surface is cut, and the outer periphery of the holder 16 is integrally formed with a pair of left and right water injection nozzles extending along the side surface of the holder 16. The holders 17 are attached from the left and right edges of the cut portion of the holder 16 with the nozzle openings facing the processing points. Reference numeral 18 is a water injection pipe, the lower end of which is connected to the root of the water injection nozzle 17 and the upper end of which is removably fitted to the connecting pipe 33 of the auxiliary drive system of the machining center. A slider 19 loosely fitted to the tool connecting shaft 9 is fitted inside the ball bearing 15 of the holder 16, and a compression spring member coaxially mounted under the slider 19 is supported by a spring pad 21. The spring force of 20 pushes it up in the direction of arrow A to urge it. Due to this pushing-up urging force, the water injection pipe 18 is firmly fitted to the connecting pipe 33, and the fitting portion has a watertight structure (see FIG. 1). Reference numeral 22 denotes a stopper having a hemispherical tip end, which is provided at an appropriate position on the lower end surface of the arm gripped portion 8 when the holder 16 is removed from the spiddle 1 of the machining center, as shown in FIG. It fits in the conical groove portion 23 and exerts the effect of positioning the water injection pipe 18 at an appropriate position. Reference numeral 13 is a grinding wheel which is a working tool, and is attached to the tip of the tool connecting shaft 9 as shown by the two-dot chain line in the figure.

The tool holder 14 will be described in more detail with reference to FIG. 3 showing a cross section taken along the line BB '.
Has a cylindrical shape with a part of the side surface cut, and the nozzle openings of the water injection nozzle 17 are located on the left and right edges of the cut portion, and the top 13a of the grinding surface of the grinding wheel 13 (ground) It is adjusted in the preset stage so that it will become a point).

In order to mount and drive such a tool holder 14,
The connecting pipe 33 provided on the ring gear 30 on the machining center side of the present invention and the water injection pipe 18 on the tool holder 14 side are automatically fitted when the tool holder 14 is mounted. This utilizes the characteristic that when the tool holder 14 is automatically removed from or mounted on the spindle 1 of the machining center, the tool holder 14, the spindle 1 and the machining center are kept in the same positional relationship with each other. This is what you do. That is, when the tool holder 14 is removed, the spindle 1 is always at the same position with respect to the machining center (stop position in the circumferential direction).
And the tool holder 14 is removed while maintaining the same positional relationship with the spindle 1. Then, even when the tool holder 14 is mounted, the same positional relationship is maintained as described above. Therefore, when the tool holder 14 is mounted, the water injection pipe 18 automatically faces the connection pipe 33 and is connected thereto. More specifically, in this tool holder 14, as described above, the holder 16 is placed in an appropriate position with respect to the tool holder 14 by fitting the stopper 22 and the conical groove 23 on the bottom surface of the arm gripped portion 8. Because it is positioned. After all, the holder 16, and thus the water injection pipe 18 are always in a fixed position in the circumferential direction of the tool holder 14 with respect to the tool holder 14. Therefore, when the tool holder 14 is mounted on the spindle 1, the water injection pipe 18 is always mounted at a fixed position with respect to the machining center. In addition,
The length of the water injection pipe 18 at the time of fitting needs to be adjusted so that the stopper 22 does not fit into the conical groove portion 23 when the tool holder 14 is mounted on the machining center. That is, the holder 16 is rotated and stopped in the circumferential direction in accordance with the movement of the ring gear 30 arranged on the lower end surface of the outer cylinder 1a of the spindle 1 of the machining center at the time of starting the grinding work after mounting the tool holder 14. This is because if the stopper 22 is fitted in the groove 23, this becomes impossible. At this time, the integrated water injection pipe 18 and the connection pipe 33 not only serve as passages for the water injection liquid, but also serve to transmit the drive of the ring gear 30 on the machining center side to the holder 16. Above ring gear
The drive of 30 is a pulse motor via a worm wheel 31.
Given by 32. The drive of this pulse motor 32 is
The holder is controlled by the drive control system as the grinding point of the grinding wheel 13 relative to the workpiece moves.
16 is rotated or stopped and fixed to the holder 16 so that the nozzle port of the water injection nozzle 17 is positioned at an appropriate position.

In this way, at the same time when the tool holder 14 is mounted, the holder 16 is connected to the drive from the auxiliary drive means provided in the machining center via the water injection pipe 18 attached to the holder 16, and the grinding process is started. To be done. In this case, the workpiece to be ground is positioned and moved in the same manner as in a normal machining center. However,
In the grinding using the above machining center, the pouring of the grinding fluid is not the water pouring from the fixed position as in the conventional machining center, but the pouring nozzle 17 attached to the holder 16 that rotates and stops according to the movement of the grinding point. Since it is water injection,
Water can be constantly aimed at the grinding point. This is the greatest feature of this invention. This will be described in detail. FIG. 4 shows that the tool holder 14 is attached to the machining center of the present invention, and the plane shape thereof has four apex angles A, B, C, D.
4 is a schematic plan view for explaining water injection when grinding four side surfaces of a quadrangular workpiece 40 having a groove. FIG. The grindstone 13 is rotated in the direction of arrow P from an upper spindle (not shown), and the grinding is now being performed from the vertical angle A to the vertical angle B of the workpiece 40. At this time, the water injection nozzle 17
Since the water injection is aimed at the grinding point as indicated by arrows Q and Q ', heat generation at the grinding point can be suppressed, and at the same time, grinding debris can be removed appropriately and an excellent ground surface can be obtained. Next, grinding is performed from the vertical angle B to the vertical angle C of the workpiece 40. This state is shown in FIG. At this time, the relative movement of the grindstone 13 with respect to the workpiece can be indicated by an arrow R. On the other hand, since the holder 16 only follows the movement of the grindstone 13 and becomes the arrangement shown by the chain double-dashed line 16 ', in order to always perform water injection aiming at the grinding point, The tool 16 must be further rotated 90 ° in the circumferential clockwise direction. Such 90 ° rotation of the holder 16 causes the ring gear 30 (first
(Fig.). The drive control of the ring gear 30 is performed by the control system built in the machining center as described above. Therefore, the vertical angle B,
Also in the grinding between C, as shown in FIG. 5, water injection is always performed aiming at the grinding point. Also between the apex angles C and D, and between D and A, water injection is always performed aiming at the grinding point as described above.

Thus, in grinding using the above machining center,
Along with the movement of the grinding point, the holder 16 linked with the movement
Due to the movement of, the water injection will always be aimed at the grinding point. In particular, the holder 16 is attached to the tool holder 14 side, not to the machining center body side, and since the water injection nozzle 17 extends from the vicinity of the grindstone 13, the direction of water injection to the processing point can be made very accurately. Can be set. Further, since the holder 16 is attached to each tool holder (the type of machining tool is different) equipped in the machining center, the tool is replaced every time the tool is exchanged (replacement of the tool holder) in the actual machining work. The pre-positioned injection nozzle is set together with the tool according to the processing, and it is not necessary for each person to manually readjust the height and direction of the nozzle.

In the above embodiment, the fitting portion of the water injection pipe 33 has a small outer diameter at the tip of the water injection pipe 18 as shown in FIG. Although it has been expanded so as to facilitate the fitting, this relationship may be reversed.

Further, when water is injected at high pressure, water leaks from the fitting portion and the fitting of the two easily separates. Therefore, as shown in FIG. 7, a rubber packing 33a is adhered to the inner wall of the connecting pipe 33. The tip of the water injection pipe 18 may be inserted into the gap between the rubber packing 33a and the inner wall of the connection pipe 33. By doing this, even if high-pressure water injection is performed, the rubber packing
Since 33a receives the water pressure and pushes the inner wall of the fitting portion from the inside to the outside, the boundary between the two is kept in close contact with each other and is not separated.

Further, in the above grinding process, the workpiece to be ground is not limited to the square shape as described above, but any shape such as a hexagonal shape, an octagonal shape, a polygonal shape, a circular shape, a special shape, or the like. You may be This is because it is sufficient to convert the arithmetic expression for control input to the auxiliary drive control system at the preset stage of the machining center as described above.

Further, the machining tool to be attached to the machining center of the present invention is not limited to the above-mentioned grinding wheel 13, but can be selected from various machining tools normally equipped in machining centers such as milling cutters and drills. Therefore, it can be used for various processing operations. However,
The machining center of the present invention is characterized by being able to always perform water injection by aiming at a processing point, and it is optimal from the point of view of its effect that the machining center has conventionally been subjected to grinding, which has many problems. it is conceivable that.

Further, in the machining center, as shown in FIG. 8, in order to increase the number of water injection nozzles 17 by providing two (a) or three (b) water injection pipes 18, respectively, a connecting pipe of the lower end surface of the ring gear 30 is provided. 33 may be increased to 2 or 3. By doing so, it is possible to perform more precise water injection by appropriately combining low-pressure water injection and high-pressure water injection.

Further, in the above machining center, the ring gear 30
Since the water injection pipe 18 that transmits the rotational drive of the above to the holder 16 receives the rotational drive only at its upper end portion (the connection portion with the connection pipe 33), a load is applied in the rotation direction, which may cause damage. . Therefore, as shown in FIG. 9, the cylinder 35 is provided at a position opposite to the rotation direction of the ring gear 30 with respect to the water injection pipe 18, and the rotation of the ring gear 30 is started as shown by the arrow and at the same time, The outer wall surface of the water injection pipe 18 may be pressed by the piston rod tip 36 of the cylinder 35.

Further, in the above embodiment, the holder 16 is rotatably attached to the tool connecting shaft 9 via the ball bearing 15, but the holder 16
It does not matter which mode is used to rotatably attach the tool to the tool connecting shaft 9.

〔The invention's effect〕

As described above, the machining center of the present invention has an unprecedented superiority in that it is possible to always carry out water injection aiming at the processing point only by attaching several parts to the body and tool holder of the conventional machining center. It is effective. Therefore, when the machining center of the present invention is used and the machining tool is mounted through a predetermined tool holder suitable for this machining, the water is always injected to the machining point which is the contact point between the workpiece and the machining tool. Therefore, heat generation at the processing point can be suppressed, and at the same time, grinding debris can be appropriately removed, and accurate processing can be realized. Further, the damage and wear of the working tool are extremely reduced, and the working efficiency can be improved. In particular, in the machining center of the present invention, since the water injection nozzle is attached to the tool holder equipped in the machining center, water is injected from the vicinity like a tool, and the direction of water injection to the machining point is very accurate. Can be set. Moreover, in the actual machining work, every time the tool is replaced (the tool holder is replaced),
Since the water injection nozzle that is pre-positioned according to the machining is set together with the tool, there is an advantage that it is not necessary for each person to manually readjust the height and direction of the nozzle.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention, FIG. 2 is a front view of a tool holder used in the present invention, and FIG.
FIG. 4 is a cross-sectional view taken along the line BB ′ of FIG. 4, FIGS. 4 and 5 are explanatory views of a machining process using an embodiment of the present invention, and FIG. 6 is an explanatory view of a connecting portion between a machining center and a tool holder of the present invention,
FIG. 7 is an explanatory view of a modified example thereof, FIG. 8 is an explanatory view showing a modified example of a water injection nozzle and a water injection pipe of a tool holder used in the present invention, and FIG. 9 shows a part of another embodiment of the present invention. A front view, FIG. 10 is a vertical cross-sectional view showing a conventional machining center, and FIG. 11 is a partial perspective view showing a water injection mechanism of the conventional machining center. 1 ... spindle, 1a ... spindle outer cylinder, 4 ... fitting part, 5 ... chuck part, 6 ... holding part, 7 ... engaging groove part, 8 ... arm held part, 9 ... Tool connecting shaft, 13 ……
Grinding wheel, 14 …… Tool holder, 15 …… Ball bearing, 16 ……
Holder, 17 …… Water injection nozzle, 18 …… Water injection pipe, 19 ……
Slider, 20 ... compression spring, 21 ... spring contact, 22 ... stopper, 23 ... groove, 30 ... ring gear, 30a ... guide ring, 31 ... worm wheel, 32 ... pulse motor, 33 ... Connecting pipe

Claims (3)

[Claims] 1. A machining center provided with a spindle capable of fitting a tool holder, to which a water injection nozzle and a holder having a water injection pipe are rotatably attached, inside the lower end thereof, and spindle drive means for driving the spindle. A connecting means that is detachably fitted to the water injection pipe attached to the holder of the tool holder so as to communicate with the water injection pipe at the time of fitting, and a supply means for supplying the water injection liquid to the connection means. An auxiliary drive means for driving the holder via the connecting means, and a control for controlling the drive by the auxiliary drive means of the holder so that the water injection port of the water injection nozzle attached to the holder at the time of processing faces the processing point. A machining center having means. 2. The machining center according to claim 1, wherein a ring gear, a worm gear meshing with the ring gear, and a pulse motor for intermittently rotating the ring gear are provided as auxiliary driving means for driving the holder. 3. As a control means for controlling the drive by the auxiliary drive means, a reading means for outputting a signal for reading the position of the processing point and an output signal of the reading means are inputted and attached to the holder based on the signal. And an arithmetic processing means for obtaining and outputting a rotation angle of the holder such that the water injection port of the water injection nozzle faces the processing point, and a signal transmission means for transmitting a signal for controlling the auxiliary drive means based on the output. The machining center according to claim 1 or 2.