Machine tool

Abstract

To provide a machine tool that is configured so that consumptions of compressed air can be reduced.SOLUTION: The machine tool is provided with: various types of machining devices that machine work-pieces in a machining chamber; a coolant device that supplies coolants fed out from a coolant tank by a pump into the machining chamber by controlling a valve; a circuit for air purge through which pressure of compressed air from an air supply source is regulated by an electropneumatic regulator and then is fed to device covers provided to cover the machining devices; and a control device that drives and controls the various types of machining devices, the coolant device and the circuit for air purge. The control device makes the electropneumatic regulator regulate the pressure in response to supply of coolants to the machining chamber by the coolant device.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a machine tool configured to reduce the consumption of compressed air used to prevent the intrusion of coolant.

Background Art

[0002] In a machine tool, coolant is used for cooling a machining part and flushing chips and the like, and is vigorously jetted into the machining chamber during machining. Therefore, the spindle device and the like have a structure for gripping and rotating a workpiece, and the spindle chuck is located in the machining chamber, but the rotating drive part where bearings such as bearings are present is covered by a cover. However, since there is a slight gap in the rotating drive part, a configuration for preventing the intrusion of coolant is adopted. In particular, since the coolant may contain chips and the like and requires attention, Patent Document 1 below also discloses a configuration for preventing the intrusion of machining fluid and dust into the inside of the rotating shaft.

[0003] The conventional example described in the same document is a spindle device that prevents the intrusion of chips and the like. Specifically, an annular groove is formed on the outer peripheral surface of the housing over the entire circumference, and one end of an air purge hole formed by bending through the housing is connected. A pump is connected to the other end side of the air purge hole, and compressed air is supplied. The compressed air is supplied over the entire circumference of the annular groove, and the pressure of the labyrinth seal is made uniform in the circumferential direction. By introducing external compressed air from the air purge hole into the labyrinth seal in this way, the pressure of the labyrinth seal becomes higher than that outside the spindle device, and an air curtain is formed, preventing the coolant falling on the spindle device from entering the front bearing side when machining a workpiece.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, these days, energy conservation is required from both aspects of ensuring stable energy supply and preventing global warming, and the same applies to machine tools. As described above, compressed air is used in machine tools to prevent coolant from entering the bearing parts and the like. If compressed air is supplied to a narrow place as in the conventional example, the consumption amount is small, so the power consumption can be suppressed. However, a large amount of compressed air is required to create a pressure difference with the machining chamber by supplying compressed air to a device cover that surrounds the spindle device and the like, which will be accompanied by corresponding power consumption. On the other hand, in order to maintain stable driving of the machine tool, it is essential to prevent the intrusion of coolant.

[0006] Therefore, an object of the present invention is to provide a machine tool that reduces the consumption amount of compressed air in order to solve such problems.

Means for Solving the Problems

[0007] The machine tool according to the present invention includes various processing devices that execute processing of a workpiece in a machining chamber, a coolant device that supplies coolant sent out from a coolant tank by a pump to the machining chamber by valve control, an air purge circuit that adjusts the pressure of compressed air from an air supply source by an electro-pneumatic regulator and sends it into a device cover provided to cover the processing device, and a control device that drives and controls the various processing devices, the coolant device, and the air purge circuit. The control device performs the pressure adjustment in the electro-pneumatic regulator in correspondence with the supply of coolant to the machining chamber by the coolant device.

Effects of the Invention

[0008] According to the above configuration, by sending compressed air into the device cover that covers the processing device and increasing the pressure inside the device cover from the processing chamber side, it is possible to prevent the coolant from entering the device cover. Moreover, by adjusting the flow rate of the compressed air sent into the device cover with an electro-pneumatic regulator, the amount of compressed air consumed can be suppressed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0010] An embodiment of the machine tool according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the machine tool of this embodiment, and in particular, it is a perspective view showing the internal structure of the machine body. The machine tool 1 of this embodiment is a small-sized NC lathe in which various processing devices for processing a workpiece are assembled on a slant-type bed 6. The bed 6 has an inclined upper surface as the assembly surface 601 of the device, and various processing devices are assembled there. The machine tool 1 is provided with, as processing devices, a first workpiece spindle device 3 that rotatably holds a workpiece, a second workpiece spindle device 4 that is arranged opposite to the first workpiece spindle device 3 and rotatably holds a workpiece, and a turret device 5 having a plurality of turret tools T.

[0011] The first work spindle device 3 installed at the front left part of the bed 6 is assembled such that the center line of its spindle is in the machine width direction and horizontal. The second work spindle device 4 is arranged coaxially with the first work spindle device 3. In this embodiment, the direction parallel to the spindle of the first work spindle device 3 (the left - right width direction of the bed 6) will be described as the Z - axis. And the second work spindle device 4, which is coaxial with the first work spindle device 3, is configured to move in the machine width direction parallel to this Z - axis.

[0012] In the first work spindle device 3, a spindle is rotatably supported by bearings within a casing 11. A chuck mechanism 12 is fixed to the end of the spindle. When the spindle rotates by a first spindle motor, rotation is imparted to the work held by the chuck mechanism 12. Similarly, in the second work spindle device 4, a spindle is rotatably supported by bearings within a casing 15. A chuck mechanism 16 is fixed to the end of the spindle. When the spindle rotates by a second spindle motor, rotation is imparted to the work held by the chuck mechanism 16.

[0013] In the first work spindle device 3, a spindle base 13 integrated with the casing 11 is fixed to the bed 6. In the second work spindle device 4, the casing 15 is integrated with a spindle base 14 that is slidable and is configured to move in the Z - axis direction. Two guide rails 18 parallel to the Z - axis are fixed to the mounting surface 601 of the bed 6, and a linear guide is configured such that a spindle table 17 carrying the spindle base 14 slides. Also, a ball screw mechanism is configured to linearly move the spindle table 17 along the guide rails 18 by a screw shaft 19 parallel to the Z - axis, and the rotation shaft of a Z - axis servo motor 20 is connected to the screw shaft 19.

[0014] The turret device 5 has a plurality of turret tools T attached to a disk-shaped tool rest 21 at equal intervals in the circumferential direction, and a rotating shaft that rotatably supports the tool rest 21 is rotatably supported by bearings. The rotation of a indexing servo motor 22 is transmitted to the rotating shaft via a rotation transmission mechanism. The turret device 5 is configured such that a turret main body 28 including the tool rest 21 moves in the Z-axis direction, in a vertical direction orthogonal to the Z-axis, and in a direction of 45 degrees, which is the same as the inclination of the mounting surface 601. In the present embodiment, the vertical direction will be described as the Y-axis, and the direction of the inclination of the mounting surface 601 will be described as the X-axis.

[0015] The turret device 5 is also provided with a linear guide by two guide rails 23 parallel to the Z-axis, and is configured to be capable of linear movement in the Z-axis direction by a ball screw mechanism including a screw shaft 25 and a Z-axis servo motor 26. Further, a turret X-axis slide 27 is similarly assembled to the turret table 24 so as to be capable of linear movement in the X-axis direction, and the turret main body 28 is also assembled to the turret X-axis slide 27 so as to be capable of linear movement in the Y-axis direction.

[0016] The workpiece processing of the machine tool 1 can be the first processing on the workpiece on the side of the first workpiece spindle device 3 and the second processing on the workpiece on the side of the second workpiece spindle device 4. In the first processing, with respect to the workpiece held by the chuck mechanism 12, the turret tool T indexed by the turret device 5 moves in each axial direction by drive control of the Z-axis servo motor 26. Then, external diameter processing using a tool bit on the rotating workpiece, drilling using a drill on the workpiece with the phase determined, and the like are performed. In the second processing, the second workpiece spindle device 4 moves to the side of the first workpiece spindle device 3, and the workpiece is switched from the chuck mechanism 12 to the chuck mechanism 16, and predetermined processing such as turning similar to the first processing is performed on the back surface of the workpiece.

[0017] During such workpiece machining, coolant is used to cool the machined portion of the workpiece where the tool contacts the workpiece and to wash away the chips generated by the workpiece machining. The machine tool 1 is provided with a coolant device 7 (see Fig. 4) for supplying coolant to the machining portion and the like. Although not shown in detail, the coolant device 7 is provided with a coolant tank having a discharge conveyor in the lower space 605 of the bed 6. The used coolant collected in the coolant tank is filtered through a filter and sent again to the machining portion and the like by a coolant pump. Then, the supply of the coolant is performed by valve control of an electromagnetic on-off valve in the coolant device 7.

[0018] Here, Fig. 2 is a perspective view showing a partial structure constituting the machining chamber with respect to the internal structure of the machine tool 1 shown in Fig. 1. The machining chamber 30 where workpiece machining is performed is configured as a closed space surrounded by a cover member so that the coolant supplied in a jet state does not adhere to the drive portions inside the machine and does not leak outside the machine. Further, the entire second workpiece spindle device 4 moving inside the machining chamber 30 except for the spindle chuck 16 is covered by the spindle cover 31, and the turret device 5 such as the turret body 28 except for the tool rest 21 is covered by the turret cover 32. Note that the first workpiece spindle device 3 shown in Fig. 2 is surrounded by a larger closed space but is omitted in the drawing.

[0019] As shown in Fig. 2, the machining chamber 30 is configured as a closed space including the floor surface where the guide rails 18 and 23 are located. Further, the machining devices are covered by the spindle cover 31 and the like, and a sealing structure against the coolant is adopted. The floor surface of such a machining chamber 30 is constituted by a combination of a fixed cover and a movable cover because the spindle table 17 and the turret table 24 move in the Z-axis direction. A plurality of movable covers are arranged so as to overlap from the rear side to the front side of the machine body, and are configured such that coolant and chips do not flow down to the front side of the machine body.

[0020] The spindle cover 31 has a spindle 33 to which the spindle chuck 16 is attached protruding therefrom. Therefore, coolant enters through the gap. Thus, the machine tool 1 performs an air purge to prevent the entry of coolant by sending compressed air into the spindle cover 31 to make the air pressure inside the cover higher than that in the machining chamber 30. Such countermeasures against the entry of coolant are taken not only for the second workpiece spindle device 4, but also for the spindle cover provided for the turret cover 32 of the turret device 5 and the spindle cover of the first workpiece spindle device 3 (not shown).

[0021] Figure 3 is a circuit diagram showing an air purge circuit for the spindle cover 31, the turret cover 32, etc. (collectively referred to as the "device cover 35"). An air compressor 41 installed in the factory is used for air purge, and an air pipe 42 extending to a plurality of device covers 35 of the machine tool 1 is connected thereto as an air supply source. A detent-equipped switching valve 43 that can be switched by lever operation is connected to the air pipe 42 in order from the air compressor 41. Since the air purge circuit 8 is for preventing the influence of coolant on bearings, etc. of the spindle in the casing 15, a waste oil mist separator is attached to the switching valve 43, and a filter 44 with a manual discharge function is connected to the secondary side of the switching valve 43.

[0022] Also, an air solenoid on-off valve 45 and a pneumatic regulator 46 are sequentially connected to the secondary side of the filter 44 in the air pipe 42, and further, a branch pipe separated at the secondary side of the pressure gauge 47 is connected to each device cover 35. The air purge circuit 8 is configured such that compressed air is constantly sent from the air compressor 41 into the air pipe 42. Also, when the power of the machine tool 1 is turned on, the switching valve 45 is switched from the normal position where it is closed to the open position. And in this embodiment, the adjustment of the pressure and flow rate of the compressed air supplied from the air compressor 41 is configured to be performed by control of the pneumatic regulator 46.

[0023] Next, FIG. 4 is a block diagram showing a control system for controlling the machine tool 1. A microprocessor (CPU) 51, a ROM 52, a RAM 53, and a non-volatile memory 54 are connected to the control device 10 of the machine tool 1 via bus lines. The CPU 51 comprehensively controls the entire control device. The system program and control parameters executed by the CPU 51 are stored in the ROM 52, and temporary calculation data, display data, etc. are stored in the RAM 53. Further, information necessary for the processing performed by the CPU 51 is stored in the non-volatile memory 54, and the sequence program of the machine tool 1 and the like are stored therein.

[0024] The control device 10 is provided with an I / O port 55. Drive motors such as the first and second work spindle devices 3 and 4 and the turret device 5 are connected to the I / O port 55 via drivers. In addition, the control device 10 is also connected to the air purge circuit 8 via a driver so as to be able to control the switching valve 45 and the pneumatic regulator 46. An operation display device 9 is connected to the I / O port 55. The operation display device 9 is provided with a touch panel type monitor in addition to various operation buttons and switches, and various information such as the display of the operation screen and the operation status is displayed on the monitor. The operation display device 9 also has a function as an input interface.

[0025] Subsequently, in the factory, compressed air is constantly sent from the air compressor 41 to the air pipe 42 to the machine tool 1. In the machine tool 1, since coolant is jetted into the machining chamber 30 during workpiece machining, an air purge is performed so that the coolant does not enter from the gap between a part of various machining devices exposed into the machining chamber 30 and the device cover 35. As shown in FIG. 3, the switching valve 43 is switched from the closed valve state to the open valve state by a lever operation, and compressed air is sent from the air compressor 41 to the machine tool 1.

[0026] The compressed air passing through the switching valve 43 flows through the filter 44 to the secondary side of the air solenoid on-off valve 45 that has been opened, and is sent into the device cover 35 by a predetermined pressure (predetermined flow rate) adjusted by the pneumatic regulator 46. The air solenoid on-off valve 45 is switched and controlled to the open state shown in the figure when the driving of the machine tool 1 is started. The pneumatic regulator 46 can perform adjustment control of air pressure proportional to the input of an electric signal. In this embodiment, adjustment control of high pressure, low pressure, and stop is performed. That is, it is configured to adjust the increase and decrease in the flow rate of the compressed air supplied to the device cover 35 along with the pressure adjustment of the pneumatic regulator 46.

[0027] The workpiece machining performed by the machine tool 1 is, for example, continuous machining of the same workpiece in a lot number from several to several tens. The same process is repeated, and the loading and unloading of the workpiece by the autoloader and the transfer of the workpiece between the autoloader and the spindle chuck are performed. Therefore, since coolant is not always supplied (sprayed) into the machining chamber 30, there are also differences in the degree of the situation where coolant can enter the device cover 35. Therefore, in this embodiment, as shown in FIG. 5, pressure adjustment control linked to the timing of supplying coolant into the machining chamber 30 is performed.

[0028] FIG. 5 is a diagram simply showing the ON / OFF timing of the coolant solenoid on-off valve for supplying coolant and the pressure control timing of the pneumatic regulator 46 related to the valve control. The pneumatic regulator 46 is switched and controlled to be at a high pressure during machining when coolant is sprayed and to be at a low pressure at the timing when machining in which the spraying of coolant stops ends. Therefore, the switching of the pneumatic regulator 46 is performed in relation to the energization of the coolant solenoid on-off valve that controls the spraying of coolant.

[0029] When the coolant is vigorously injected into the machining chamber 30, the pressure inside the device cover 35 must already be increasing. Also, when the machining of the workpiece is completed, the injection of the coolant stops, but even then, inside the machining chamber 30, the coolant after injection is flowing down vigorously along the device cover 35 and the like. Therefore, even immediately after the injection of the coolant stops, the pressure inside the device cover 35 must still increase so that the coolant flowing down through the machining chamber 30 does not enter through gaps or the like.

[0030] Therefore, the pneumatic regulator 46 is switched to a high pressure a certain time earlier than the opening of the electromagnetic on-off valve for the coolant and is switched to a low pressure a certain time later than the closing of the electromagnetic on-off valve for the coolant. Furthermore, the pneumatic regulator 46 cuts off the flow of compressed air by stop control and stops the supply into the device cover 35. Such stop control by the pneumatic regulator 46 is performed when the drive of the machine tool 1 is stopped, that is, when the first workpiece spindle device 3, the second workpiece spindle device 4, and the turret device 5 are in a stopped state. For example, it is during setup such as replacing the spindle chuck or tools due to a change in the machined workpiece, or during maintenance for tool collisions or the like.

[0031] Thus, the machine tool 1 of the present embodiment can prevent the intrusion of the coolant by increasing the pressure inside the device cover 35 from the machining chamber 30 side by sending compressed air into the device cover 35 that covers the machining device. Thereby, it is possible to avoid the malfunction of bearings and the like that make up the machining device due to the influence of the coolant. Conventionally, a large amount of compressed air was consumed to obtain such an effect, but according to the present embodiment, energy saving can be realized by suppressing the flow rate of the compressed air supplied to the device cover 35 by the pneumatic regulator 46.

[0032] In particular, in the case where spaces such as the first work spindle device 3 that should be in a high-pressure state, like the machine tool 1, are a plurality of device covers 35 such as the first work spindle device 3 and each of their volumes is large, the amount of compressed air consumed will become large. As a result, for the air purge performed on a plurality of machine tools installed in the factory, an even larger amount of compressed air is used, and the power consumption of the compressor has become large. In contrast, in the present embodiment, as described above, by appropriately adjusting the flow rate of the compressed air with the electropneumatic regulator 46, it becomes possible to reduce the power consumption of the compressor associated with the reduction in the flow rate of the compressed air.

[0033] As described above, one embodiment of the present invention has been described. However, the present invention is not limited to this, and various modifications are possible without departing from the spirit thereof. For example, the machine tool 1 of the above-described embodiment is an example, and it may be a lathe, a machining center, or a boring machine having other configurations.

Description of Reference Numerals

[0034] 1... Machine tool 3... First work spindle device 4... Second work spindle device 5... Turret device 7... Coolant device 8... Circuit for air purge 10... Control device 12, 16... Spindle chuck 21... Turret tool post 31... Spindle cover 32... Turret cover 35... Device cover 46... Electropneumatic regulator 41... Air compressor

Claims

1. Various processing devices for performing processing of a workpiece in a processing chamber, a coolant device that supplies coolant sent out from a coolant tank by a pump to the processing chamber by valve control, an air purge circuit that adjusts the pressure of compressed air from an air supply source by an electro-pneumatic regulator and sends it into an equipment cover provided to cover the processing device, a control device that drives and controls the various processing devices, the coolant device, and the air purge circuit, characterized by comprising a machine tool in which the control device performs pressure adjustment in the electro-pneumatic regulator in correspondence with the supply of coolant to the processing chamber by the coolant device.

2. The machine tool according to claim 1, wherein the control device raises the adjustment pressure in the electro-pneumatic regulator during the supply of coolant to the processing chamber by the coolant device and lowers it when the supply of coolant to the processing chamber by the coolant device is stopped.

3. The machine tool according to claim 2, wherein the control device shuts off the flow of compressed air in the electro-pneumatic regulator when the driving of the various processing devices is stopped.

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