machine tool

Abstract

Machine tool, including: a main shaft head (2) which holds a main shaft (7) so that it is freely rotatable and moves vertically; a turret tool exchange device (3) having several holders around its circumference and being able to hold several tools (4), each attached to the main shaft (7), by means of the holders, and being held in a manner freely rotatable about a predetermined axis of rotation, the predetermined axis of rotation of the turret tool exchange device (3) being inclined relative to the main shaft (7); and a unit (16) for attaching a rotary tool holder (17), which attaches a rotary tool holder (17), which rotary tool holder (17) holds a rotary tool, in such a way that the rotary tool holder (17) is removable; wherein the unit (16) for attaching the rotary tool holder (17) is fixed in such a way that it does not change its position and attitude in relation to the main shaft head (2), and the unit (16) for mounting the rotary tool holder (17) is provided in an area where no disruptive interference is caused during the tool exchange carried out by the turret tool exchange device (3).

Description

GENERAL STATE OF THE ART1. Field of the invention

[0001] The present invention relates to a machine tool, and in particular to a machine tool which is provided with a unit for attaching a rotary tool holder. 2. Description of the state of the art

[0002] Fig. Figure 1 illustrates a turret-type table-type machine tool. A main shaft head 2, held in such a way that it is movable in one axial direction (a Z-direction, a perpendicular direction in the drawing) of a main shaft 7, is mounted on a column 1 via a linear motion guide 9. A main axis unit 8 is attached to the main shaft head 2. Various types of tools 4, which can be exchanged by a tool changer (a turret) 3, are mounted on the main shaft 7, which is provided by the main shaft unit 8. The tool 4 rotates at different speeds together with the main shaft 7 and performs various relative movements with respect to a workpiece 6, which is fixed to a table 5, according to a type of machining operation (see JP 2004-74335 A).The table 5 is held in such a way that it is movable in two directions which are orthogonal to one direction of the main shaft 7 and orthogonal to each other (X and Y directions, a horizontal direction in the drawing and a direction perpendicular to the plane of the drawing).

[0003] While the tool 4 cuts the workpiece 6, a hinged door 11, provided on a splash guard 10, is closed. Cutting fluid, supplied by a cutting fluid pump 13 through a cutting fluid hose 12 from a cutting fluid tank 13b, is discharged from a nozzle 12b, attached to an end section of the cutting fluid hose 12, to the tool 4, which is mounted on the main shaft 7 and rotates. The cutting fluid, which flows in liquid form from a machined section, runs down an inner wall of the splash guard 10 and is collected in a cutting fluid tank (not shown).The cutting fluid in the form of a fine mist is sent, together with air that is drawn into the splash guard from an opening section provided on a lower section of the machine, to a line 14 provided on an upper section of the machine.

[0004] There is a case where turning and grinding are performed using a turret machine tool. In this case, a procedure is generally used whereby a rotary device, which rotates the workpiece 6, is mounted on the table 5, and a turning tool is mounted on the main shaft 7 of the turret machine tool to machine the workpiece.

[0005] On the other hand, JP 2012-210681 A discloses a technique in which turning can be performed in such a way that, in a turret-type traveling column machine tool capable of moving a main shaft head to any position in the X, Y, and Z directions based on the control of the drive by respective motors, a turning tool is fixed to the main shaft head, which moves synchronously with a main shaft, without the turning tool being attached to the main shaft. The machine tool disclosed in JP 2012-210681 A is provided with a base arranged on a bottom surface, a slide provided on the base via a Y-direction movement device, a column provided on the slide via an X-direction movement device, and a main shaft head provided on a front surface of the column via a Z-direction movement device.

[0006] The machining process using a turning tool on a main shaft is generally employed for turning on a turret lathe, and recently, along with advances in turning tools, the feed rate has been increased. However, when performing high-speed machining, the problem arises that machining with a turning tool attached to a main shaft is limited to light cutting.

[0007] Furthermore, in the turret machine tool disclosed in JP 2012-210681 A, a turning tool is fixed to the main shaft head by a clamping device, and the clamping device moves relative to the main shaft head to prevent interference between the turning tool and a workpiece and to prevent a reduction in the machining area. However, the machine tool has the drawbacks of a complex design and the inability to supply cutting fluid to the tip of the turning tool.

[0008] Furthermore, JP 2012-210681 A (paragraph "0047") describes the use of a holding tool that holds a rotary tool in such a way that the rotary tool is removable. However, the specific design is not described, and there is the problem that cutting fluid cannot be supplied to the tip of the rotary tool.

[0009] From JP H05-92301 A, a machine tool is known that is equipped with a workpiece spindle which holds a workpiece detachably and rotatably, and a spindle head which is movable relative to the workpiece spindle, and which is provided with a tool holder and a unit for mounting the tool holder. JP H06-126571 A is directed to a tool holding device for a machine tool in which rotating tools and cutting tools have separate holding positions and can be exchanged by a single arm. US 3,893,355 A describes a coolant supply system for a machine tool, and JP 2005-040870 A is directed to an improved cleaning mechanism for chips near the turning and milling tools of a machine tool. BRIEF SUMMARY OF THE INVENTION

[0010] In view of the problems of the prior art mentioned above, it is an object of the present invention to provide a machine tool in which a unit for attaching a rotary tool holder to a main shaft head is provided, so that an increase in the weight and number of machining tools attached to a turret tool exchange device can be prevented and a reduction in the machining area in which a workpiece is machined can be prevented.

[0011] Another object of the present invention is to provide a machine tool that is capable of supplying a coolant to the tip of a rotary tool.

[0012] Another object of the present invention is to provide a machine tool that is able to confirm whether a rotary tool holder has been brought into close contact with a unit for mounting the rotary tool holder.

[0013] Furthermore, another object of the present invention is to provide a machine tool in which the unit for attaching the rotary tool holder is able to clamp and release the rotary tool holder by means of a hydraulic pressure control.

[0014] Furthermore, another object of the present invention is the provision of a machine tool in which the activity of replacing a rotary tool can be carried out by a robot.

[0015] Furthermore, another object of the present invention is to provide a machine tool in which the unit for mounting the rotary tool holder does not interfere with a tool that is exchanged during a tool change performed by the turret tool exchange device. These objects are achieved by a machine tool according to claim 1. Further advantageous embodiments are defined in the dependent claims.

[0016] A machine tool according to the present invention comprises a main shaft head which holds a main shaft so that it is freely rotatable and moves vertically, a turret tool exchange device on the circumference of which several holders are provided and which is able to hold several tools, each attached to the main shaft, by means of the holders, and which is held in a manner that allows free rotation about a predetermined axis of rotation, and a unit for attaching a rotary tool holder which attaches a rotary tool holder, which holds a rotary tool, to the main shaft head in such a way that the rotary tool holder is removable, wherein the unit for attaching the rotary tool holder is fixed in such a way that it does not change its position and attitude with respect to the main shaft head.

[0017] According to the present invention, an increase in the weight and number of machining tools attached to the turret tool exchange device can be prevented, and a reduction in the machining area in which a workpiece is machined can be prevented.

[0018] The unit for mounting the rotary tool holder can have hydraulic pressure inlet ports that clamp and release the rotary tool holder. Accordingly, the unit for mounting the rotary tool holder is capable of clamping and releasing the rotary tool holder via hydraulic pressure control.

[0019] The unit for mounting the rotary tool holder can have a coolant inlet port for supplying coolant to the tip of the rotary tool. Accordingly, coolant can be supplied to the tip of a rotary tool.

[0020] The mounting unit for the rotary tool holder can have an air inlet port to confirm the tight contact of the rotary tool holder. This allows confirmation that the rotary tool holder is in tight contact with the mounting unit.

[0021] The rotary tool holder can be attached to and removed from the tool holder mounting unit by a robot or a loader. Accordingly, the robot can perform the task of changing a rotary tool.

[0022] The mounting unit for the rotary tool holder can be positioned in an area where it does not interfere with the tool change performed by the tool changer. This prevents the mounting unit from interfering with a tool being exchanged during the tool change performed by the turret tool changer. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above-described and other objects and features of the present invention will become apparent from the description of the following embodiments with reference to the accompanying drawings. In the drawings illustrative Fig. 1 a turret machine tool; illustrative Fig. 2 a state in which a unit for attaching a rotary tool holder is fixed to a main shaft head; illustrative Fig. 3 a state in which the unit for attaching the rotary tool holder to the main shaft head is fixed, as seen from a side face of the machine tool; illustrative Fig. 4 a piping system connecting the unit for mounting the rotary tool holder and an external device; illustrative Fig. 5 a clamping activity and a release activity of the unit for attaching the rotary tool holder; illustrative Fig. 6. a replacement of a rotary tool holder, which is carried out by a robot; and illustrative Fig. 7 a method for grasping a rotary tool holder with one hand for the purpose of exchanging the rotary tool holder. DETAILED DESCRIPTION OF PREFERRED EXECUTION FORMS

[0024] An embodiment of the present invention will be described below with reference to the accompanying drawings.

[0025] As described in the prior art, examples of a turret machine tool include the moving table turret machine tool described, for example, in Japanese Patent Publication No. JP 2004-74335 A, and the moving column turret machine tool described, for example, in Japanese Patent Publication No. JP 2012-210681 A.

[0026] A turret tool exchange device is provided with several holders around its circumference so that it can hold multiple tools which are attached to the main shaft by respective holders, and is held in a manner that allows it to rotate freely about a predetermined axis of rotation.

[0027] A machine tool equipped with a unit for mounting a rotary tool holder according to the present invention can be configured either as the turret-type moving table machine tool disclosed in Japanese Patent Publication No. JP 2004-74335 A or as the turret-type moving column machine tool disclosed in Japanese Patent Publication No. JP 2012-210681 A. An embodiment of the present invention is described here with reference to the one disclosed in Fig. 1 illustrated turret machine tool of the moving table type described.

[0028] Fig. Figure 2 illustrates a unit for mounting a rotary tool holder, which is fixed to a main shaft head. Furthermore, it illustrates Fig. Figure 3 shows a state in which the unit for mounting the rotary tool holder to the main shaft head is fixed, as seen from a side face of the machine tool. A rotary table 15 is arranged on the table 5. The table 5 is movable in the X and Y directions, which are orthogonal to the axis of the main shaft 7 and orthogonal to each other. The main shaft head 2 is movable in the Z direction, which is the axis of the main shaft 7. In the turret machine tool, the main shaft 7, which is held in such a way that it is movable perpendicular to one axis (the Z direction) of the main shaft 7, is attached to the column 7 via the linear motion guide 9, as shown in Figure 3. Fig. Figure 1 illustrates this. Therefore, the main shaft 7 and the main shaft head 2 move synchronously.

[0029] In the embodiment of the present invention, a unit 16 for mounting the rotary tool holder is attached to the main shaft head 2, which moves synchronously with the main shaft 7. The unit 16 for mounting the rotary tool holder is located on the main shaft head 2 in an area where, during tool changes performed by the tool change device (the turret) 3, no interfering interference occurs with respect to the main shaft 7. The unit 16 for mounting the rotary tool holder is secured by a fixing means, such as a screw, so that its orientation and position relative to the main shaft head 2 do not change. As shown in Fig. 2 and Fig. Figure 3 illustrates that the unit 16 for attaching the rotary tool holder is fixed in the area where no interfering interference is caused during the tool change carried out by the tool change device 3, i.e., fixed in an area located between the main shaft 7 and a front surface of the stator 1 and below the main shaft head 2.

[0030] When a turning tool holder 17 is attached to the unit 16 for mounting the turning tool holder in order to rotate the workpiece 6, the tool 4 is not attached to the main shaft 7. Conversely, when the machining of the workpiece 6 is carried out in such a way that the tool 6 is attached to the main shaft 7, the turning tool holder 17 is not attached to the unit 16 for mounting the turning tool holder.

[0031] The unit 16 for mounting the rotary tool holder is capable of clamping and releasing the rotary tool holder 17. The clamping and releasing operations performed by the unit 16 for mounting the rotary tool holder can be controlled by hydraulic pressure. The design of the unit 16 for mounting the rotary tool holder is described with reference to Fig. 5 described. A turning tool (a turning tool) is attached to one tip of the turning tool holder 17. The workpiece 6, which is mounted on the rotary table 15, can be machined by turning the turning tool attached to the tip of the turning tool holder 17.

[0032] Fig. Figure 4 illustrates a piping arrangement connecting the rotary tool holder mounting unit and an external device. The rotary tool holder 17 can be clamped and released by supplying hydraulic pressure from a hydraulic pressure device (not illustrated) through a clamping hydraulic pressure inlet 19 and a releasing hydraulic pressure inlet 18, respectively, provided on the rotary tool holder mounting unit 16.

[0033] Furthermore, an ultra-high-pressure coolant supply port 20 is provided on the unit 16 for mounting the rotary tool holder, so that a high-pressure coolant fluid can be supplied via the unit 16 for mounting the rotary tool holder to a rotary tool mounted at the tip of the rotary tool holder 17. Therefore, a tube for the high-pressure coolant is provided in the unit 16 for mounting the rotary tool holder so that the cutting fluid (the high-pressure coolant) can be freely supplied to a rotary tool mounted at the tip of the rotary tool holder 17.

[0034] Furthermore, unit 16 for mounting the rotary tool holder has an air inlet opening 21 to confirm whether the tool holder is in close contact, thus verifying whether the rotary tool holder 17 is properly clamped or not. Accordingly, confirmation of close contact can be provided by a detection signal from a pressure sensor (not illustrated).

[0035] Fig. Figure 5 illustrates a clamping operation (the left half of the drawing) and a release operation (the right half of the drawing) of the unit for attaching the rotary tool holder. As shown in Fig. Figure 5 illustrates how the unit 16, used to attach the rotary tool holder, applies pressure from the release hydraulic pressure inlet 18 to move a piston 22 downwards and open a drawbar (release action 24). The rotary tool holder 17 can then be removed. After replacing the rotary tool holder 17, hydraulic pressure is applied from the clamping hydraulic pressure inlet 19 to move the piston 22 upwards and initiate a clamping action 25.

[0036] Apart from the hydraulic pressure device mentioned above, any other method for fixing the rotary tool holder 17 to the mounting unit 16 can be used, provided that the method is a known method, such as a clamping method using air pressure or a manual fixing method. By fitting a special cover cap (a dummy tool) to prevent chips from entering the mounting unit 16 after machining with a rotary tool, the ingress of chips into the mounting unit 16 can be blocked, and interfering interference with the machining area can be eliminated during cutting operations performed using the main shaft of the turret machine tool body.

[0037] Fig. Figure 6 illustrates the replacement of a rotary tool holder by a robot. With the rotary tool holder 17, the automatic tool change can be performed using a robot 26, to which a hand 27 is attached for changing the rotary tool holder, or a loader (not illustrated). The robot 26 or the loader is located inside or outside the machine tool.

[0038] Fig.Figure 7 illustrates a method for grasping a rotary tool holder by hand for tool holder exchange. A movable hand claw 28 is attached to the tip of the tool holder exchange hand 27, which is mounted on the robot 26, and the tool holder 17 can be grasped accordingly. That is, the tool holder 17, which is housed in an external storage unit (not illustrated), can be attached to the tool holder by the tool holder exchange hand 27, which is mounted on the robot 26, or by the loader at the tool holder mounting unit 16. After completion of the machining operation, the mounted tool holder 17 is returned to the storage unit by the robot 26 or the loader, and the next rotary tool is selected. Thus, the same operation can be repeated.

[0039] In a rotary device of the turret machine tool according to the embodiment of the present invention, the special unit 16 for attaching the rotary tool holder to the main shaft head 2 is mounted, thus preventing an increase in the weight and number of machining tools mounted on the tool exchange device 3. Furthermore, the rotary tool holder 17 is designed to be removable, thereby "relaxing" the limitation of the machining area.

[0040] Furthermore, unit 16 is attached to the main shaft head 2 for mounting the rotary tool holder, thus increasing the force required to hold the rotary tool holder 17 and enabling high-speed, powerful cutting. Additionally, high-pressure coolant is supplied to the tip of a rotary tool, suppressing heat generation by the machining tool and facilitating chip removal. Furthermore, an automatic tool exchange process, performed by a robot 26 or a loader, is employed, enabling fully unmanned operation.

[0041] As a result, tool life can be extended and machining accuracy increased, leading to a reduction in the cost of a cutting tool for a machine tool (resource savings). In a multi-machine machining process using several machines, as is currently the case with conventional machine tools, machining cannot be performed stably with regard to maintaining machining accuracy due to the use of multiple machines. In contrast, with the machine tool according to the embodiment of the present invention, all machining steps are performed by a single machine, thus reducing machining time, machine setup costs, and labor costs. Furthermore, the machine tool according to the embodiment of the present invention is an environmentally friendly machine tool.

[0042] One embodiment of the present invention has been described above. However, the present invention is not limited to the embodiment described above; rather, the present embodiment can be implemented in other forms by making any desired modifications.

Claims

[1] Machine tool, comprising: a main shaft head (2) which holds a main shaft (7) so that it is freely rotatable and moves vertically; a turret tool exchange device (3) having several holders around its circumference and being able to hold several tools (4), each attached to the main shaft (7), by means of the holders, and being held in a manner freely rotatable about a predetermined axis of rotation, the predetermined axis of rotation of the turret tool exchange device (3) being inclined relative to the main shaft (7); and a unit (16) for attaching a rotary tool holder (17), which attaches a rotary tool holder (17), which rotary tool holder (17) holds a rotary tool, in such a way that the rotary tool holder (17) is removable; wherein the unit (16) for attaching the rotary tool holder (17) is fixed in such a way that it does not change its position and attitude in relation to the main shaft head (2), and the unit (16) for mounting the rotary tool holder (17) is provided in an area where no disruptive interference is caused during the tool exchange carried out by the turret tool exchange device (3). [2] Machine tool according to claim 1, wherein the unit (16) for attaching the rotary tool holder (17) has hydraulic pressure inlet ports (18, 19) which clamp and release the rotary tool holder (17) respectively. [3] Machine tool according to claim 1 or 2, wherein the unit (16) for mounting the rotary tool holder (17) has a coolant supply port (20) for supplying a coolant to a tip of the rotary tool. [4] Machine tool according to one of claims 1 to 3, wherein the unit (16) for attaching the rotary tool holder (17) has an air inlet connection (21) for confirming the tight contact of the rotary tool holder (17). [5] Machine tool according to any one of claims 1 to 4, wherein the rotary tool holder (17) can be attached to and removed from the unit (16) for attaching the rotary tool holder (17) by a robot (26) or a loader.

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