JPH10156661A - Machine tool incorporating clean tank for cutting fluid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent thermal displacement of machine tool which is caused by a difference in temperature between a cutting fluid and a machine body and increase machining precision by providing a controller which controls a cooling device in such a manner that temperature of the cutting fluid supplied from a clean tank coincides with temperature of the machine body substantially. SOLUTION: MC is activated, and pumps P1 to P3 , a filtration device 26, and a cooling device 22 are activated to make a coolant flow in a circulation flow passage on shaft core side 30 and a circulation flow passage on outer cylinder side 31, respectively, for circulation. Temperature of coolant Tc is detected by a coolant temperature sensor S1 , and reference temperatures Ts is detected by a reference temperature sensor S2 . A controller 23 in which each signal of these detected temperatures Tc , Ts is input controls the cooling device 22 so that temperature of coolant Tc supplied into a machine body 14 coincides with temperature Ts of the machine body 14 substantially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine tool such as a machining center (hereinafter, referred to as MC), and more particularly to a machine tool having a built-in clean tank for storing a cutting oil (hereinafter, referred to as a coolant).

[0002]

2. Description of the Related Art There is a machine tool having a spindle device such as a spindle head in an MC for processing a workpiece in a cutting area by rotating a spindle on which a tool is mounted. When processing, heat is generated in the cutting portion.
Therefore, in many cases, a coolant is supplied to a cutting portion to cool a tool or a workpiece, and chips generated by the cutting process are removed. The coolant is stored in a coolant tank, supplied from the tank to the cutting section by a pump, and then collected in the tank and used for circulation.

[0003] In a conventional machine tool, there is a machine in which this tank is built in a bed of the machine body, and the circulating coolant is always heated in a cutting portion. Therefore, as the time elapses, the temperature of the coolant in the tank increases, and as a result, the bed is also heated and thermally deformed. For example, Japanese Unexamined Utility Model Publication No. 4-112755 discloses a technology in which a tank for a coolant is built in a base frame of a machine tool so that a stable temperature state is achieved in a short time.

[0004]

However, in the technology described in this publication, the coolant stored in the tank in the base frame is not cooled. Therefore, the temperature of the coolant gradually rises as the cutting process progresses due to the heat flowing into the coolant from the chips generated in the cutting section, and it is difficult to stabilize the coolant thermally. However, there was a possibility that the temperature was increased and the heat was greatly deformed.

If the machine tool is stopped for a long time (for example, several days) in summer or the like when the temperature is high, the coolant may rot. In such a case, the coolant must be replaced and the inside of the tank must be cleaned. However, bases such as beds and base frames have many partitions and ribs inside to increase their rigidity and reduce weight, so maintenance work such as cleaning tanks built into the base is complicated. Had become.

Since the above-mentioned problems such as the thermal deformation of the machine body and the complicated maintenance work are required, the thermal effect on the machine body is reduced by installing the coolant tank in a separate place away from the machine tool body. Often do not give. For example, Japanese Utility Model Laid-Open No. 4-130146 discloses a machine tool in which a tank for coolant is set apart from the machine body. Then, the collected coolant is filtered and cleaned, stored in a clean tank, and cooled by a cooling device.

However, in this conventional technique, the temperature of the coolant in the tank and the temperature of the machine body are not related, so that there is a temperature difference between the two. Therefore, when the coolant squirts into the cutting portion, the body may be thermally deformed and the machining accuracy may be reduced. Further, this publication does not disclose a technical idea of the present invention that controls a cooling device during cutting to make the temperature of the coolant supplied to the cutting portion substantially match the temperature of the machine body. .

By the way, if the coolant tank is set apart from the machine body, for example, when the machine tool which has been stopped during the night is operated in the next morning to start the machining work, the heat capacity and heat conduction between the machine body and the coolant are required. At the start of the machining operation, there is a temperature difference between the temperature of the machine body and the temperature of the coolant due to a difference in the rate. Especially in winter morning when the temperature is falling, the temperature of the metal body is low, but the liquid coolant is hard to cool down compared to metal, so there is a considerable temperature difference between the two. Occurs.

If the coolant is circulated for a while before the machining operation is started and the machine tool is warmed up by warming up the machine tool, the temperature difference is reduced.
However, in recent years, in many cases, the working operation is started immediately after the start of the operation without warming up to improve the efficiency of the working operation. Therefore, at the start of the machining operation, a coolant having a higher temperature is supplied to a low-temperature machine body, so that the machine body is partially thermally deformed, and as a result, machining accuracy is reduced.

As described above, conventionally, there is a temperature difference between the temperature of the machine body of the machine tool and the temperature of the coolant at the start of the machining operation or during the machining operation. The processing accuracy was reduced by the displacement.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and the temperature of the cutting oil is almost always equal to the temperature of the body of the machine tool during the entire working time including the starting time of the working operation. Another object of the present invention is to provide a machine tool having a built-in clean tank for cutting oil, which can prevent a thermal displacement of the machine tool caused by a temperature difference between the two and can increase a machining accuracy.

[0012]

In order to achieve the above-mentioned object, a machine tool incorporating a clean tank for cutting fluid according to the present invention is a machine tool which circulates cutting fluid and supplies it to a cutting section. A dirty tank that is installed outside the machine tool body away from the machine, collects and stores the cutting fluid supplied to the cutting section, and is built into a base under the machine body and is transferred from the dirty tank. And a clean tank that stores the cleaned cutting fluid, and a cutting fluid temperature detecting unit that detects the temperature of the cutting fluid at a predetermined position after being ejected to the cutting section and before flowing into the clean tank. A reference temperature detecting means attached to a predetermined portion of the body to detect a reference temperature, provided in the clean tank; A cooling device for cooling the oil coolant, and the cutting supplied from the clean tank based on the cutting oil temperature detected by the cutting oil temperature detecting means and the reference temperature detected by the reference temperature detecting means. A control device for controlling the cooling device so that the temperature of the oil agent substantially matches the temperature of the body.

Preferably, the cutting fluid temperature detecting means detects the temperature of the clean cutting fluid flowing out of the dirty tank and flowing into the clean tank.

The reference temperature detecting means is attached to a predetermined position of the base such that the influence of a change in room temperature is small and the heat conduction from the cutting fluid inside and outside the clean tank is small. Preferably, the temperature of the base is detected as the reference temperature.

The reference temperature detecting means is mounted at a predetermined position of the body which is located above the base and is susceptible to a change in room temperature, and detects the body temperature at the predetermined position as the reference temperature. May be.

[0016] The cutting oil supplied from the clean tank is supplied to an axis side cutting oil circulation path passing through the inside of the main shaft of the main spindle device, and an outer cylinder passing through the inside of a main spindle support for rotatably supporting the main spindle. The cooling fluid circulation path is always supplied to the cooling fluid circulation side, and the vicinity of the inside and outside of the heating portion of the spindle device is cooled, and the cooling fluid after the cooling of the heating portion flows. It is preferable that the cutting fluid is ejected to the cutting portion by opening one or both of the flow path and the outer cylinder side cutting fluid circulation path.

Note that the cutting fluid that has flowed out of the dirty tank flows into the clean tank after fine foreign matters have been removed by a filtering device and is cleaned, and one of the cutting fluids stored in the clean tank is removed. It is preferable that the part always overflows into the dirty tank, and a floating substance floating in the cutting fluid in the clean tank is discharged to the dirty tank.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 are a schematic front view and a schematic side view of a machine tool according to an embodiment of the present invention, and FIG. 3 is a circuit diagram showing a flow path of a coolant (cutting oil).

A machine tool rotates a spindle equipped with a tool or a spindle provided with a work attachment such as a chuck for attaching a workpiece through a bearing in a spindle device such as a spindle head or a headstock. Then, the workpiece is cut in the cutting area. In the present embodiment, a vertical M is used as a machine tool.
Although the case of C (machining center) is shown, other types of machine tools such as a horizontal MC, a turning center, and an NC lathe may be used.

As shown in FIGS. 1 to 3, a column 3 is erected on the bed 2 below the body 14 of the MC 1 and the column 3 moves on the bed 2 in the Y-axis direction. A spindle head 4 as a spindle device is attached to the column 3 so as to be movable in a vertical direction (Z-axis direction). Spindle head 4
, A spindle 5 is provided in the Z-axis direction, and a tool 6 is detachably attached to a tip of the spindle 5. The axis direction of the main shaft 5 is defined as a Z-axis, and directions orthogonal to the Z-axis and forming an orthogonal coordinate system are defined as an X-axis and a Y-axis.

The table 7 provided on the bed 2 moves on the bed 2 in the X-axis direction. The body 14 includes a bed 2 as a base, a column 3, a spindle head 4, a table 7, and the like. Inside the spindle support 9 of the spindle head 4, the hollow spindle 5 rotating at a high speed is rotatably supported by bearings 10 and 11 constituting a bearing portion.

The main shaft 5 is driven to rotate by a built-in motor 12 provided between the main shaft 5 and the main shaft support 9. The bearings 10 and 11 and the built-in motor 12 are the main heat generating portions in the spindle head 4. Instead of the built-in motor 12, a motor that transmits driving force to the main shaft via a transmission member such as a belt, a pulley, and a gear may be provided outside the main shaft support to rotate the main shaft. When the workpiece 8 placed on the table 7 and the rotating tool 6 move relatively, the workpiece 8 is cut by the tool 6.

In the MC 1, the coolant L is circulated and supplied to the cutting section 13. MC1 is a small-sized dirty tank 2 that is installed outside of the machine body 14 and separates from the machine body 14 to collect and store the coolant supplied to the cutting unit 13.
0, built in the bed 2 constituting the lower part of the fuselage 14,
A large-capacity clean tank 21 for storing the clean coolant L transferred from the dirty tank 20 is provided. In the present embodiment, the inside of the bed 2 itself is used as the clean tank 21.

Further, the MC 1 is provided with a cutting oil temperature detecting means S ₁ for detecting the temperature of the coolant at a predetermined position after it is jetted to the cutting portion 13 and before flowing into the clean tank 21, and at a predetermined position of the machine body 14. a reference temperature detection means S ₂ for detecting the temperature of the mounted by reference, provided a clean tank 21, a cooling device 22 for cooling the coolant L clean tank 21, cutting fluid temperature detecting means S
₁ at the detected cutting fluid temperature (hereinafter, the coolant temperature indicated) on the basis of the reference temperature T _s detected by T _c and the reference temperature detecting means S _2, the temperature of the coolant L supplied from the clean tank 21 And a control device 23 for controlling the cooling device 22 so as to substantially match a predetermined position of the body 14 or the entire temperature.

The coolant L ₀ stored in the dirty tank 20 and containing foreign matter such as fine chips is transferred to the transfer pump P _1.
After the foreign matter is removed by the filtration device 26 and becomes a clean coolant L, it flows through the pipe 24, flows into the clean tank 21 and is stored therein. The height position of the liquid surface D ₁ of the clean tank 21 is higher than the height position of the liquid surface D ₂ of the dirty tank 20. Therefore, part of the coolant L stored in the clean tank 21 is removed from the clean tank 21 and the dirty tank 20.
As shown by an arrow E, the dirty tank 20 always overflows through the guide plate 25 provided between the dirty tank 20. Thereby, the floating matter floating in the coolant in the clean tank 21 is discharged to the dirty tank 20.

The coolant temperature sensor S ₁ as a cutting fluid temperature detecting means is preferably provided at a location where the temperature of the coolant after cooling the spindle head 4, the tool 6, the workpiece 8, etc., significantly changes. Therefore, in the present invention is provided at a predetermined position of the coolant temperature sensor S _1, until flowing into and clean the tank 21 after ejected into cutting portion 13.

The mounting position of the coolant temperature sensor S ₁ includes a collecting path 37 provided on the bed 2 for collecting the coolant in the cutting area, the dirty tank 2, and the like.
0, filtration device 26, or may be a clean tank 21, etc. in the vicinity of the outlet pipe 24, but in the present embodiment, the coolant temperature sensor S _1, the pipe 24 between the filtration device 26 and the clean tank 21 Provided. Accordingly, the coolant temperature sensor S ₁ detects the temperature _Tc of the clean coolant flowing out of the dirty tank 20 and flowing into the clean tank 21.

If the room temperature T of the place where the MC1 is installed changes, the temperature of the body 14 also changes gradually. Therefore, depending put focus on any aircraft temperature and room temperature T as the reference temperature T _s, the mounting location of the reference temperature sensing means is different. In the present embodiment, the reference temperature sensor S ₂ of the reference temperature sensing means, less affected by changes in ambient temperature T, and so heat conduction from the internal and external coolant clean tank 21 is small, from the clean tank 21 It mounted in a predetermined position distant bed 2, and detects the temperature of the bed 2 as the reference temperature T _s.

In this embodiment, the main object is the body temperature.
May be detected reference temperature T _s focuses room temperature T.
In this case, the reference temperature sensor S ₃ as the reference temperature sensing means, located above the base is attached to a predetermined position of the sensitive body the influence of changes in ambient temperature T, the body temperature of the predetermined position it may be detected as the reference temperature T _s. Specifically, for example, the column 3 located above the bed 2
Mounted on the central rear portion upper may detect the temperature of the column 3 as the reference temperature T _s. Temperature sensors S _{1 to} S ₃
May be any type, but a thermistor temperature sensor which is strong against disturbance is desirable.

In the MC 1, the coolant supplied from the clean tank 21 is supplied to a cutting oil circulation path (hereinafter referred to as an axis-side circulation path) 30 on the axis side passing through the inside of the spindle 5 of the spindle head 4. , And is always supplied to a cutting oil circulation path (hereinafter, referred to as an outer cylinder side circulation path) 31 on the outer cylinder passing through the inside of the spindle support 9 that rotatably supports the spindle 5. The vicinity of the inside and the vicinity of the outside of the heat generating portion are cooled, respectively. Then, by opening one or both of the axial-side circulation flow path 30 and the outer cylinder-side circulation flow path 31 through which the coolant after cooling the heat-generating portion flows, the coolant is jetted to the cutting portion 13. .

The coolant L stored in the clean tank 21 and cooled by the cooling device 22 in the axial-side circulation flow path 30 is continuously drawn out by the axial flow path pump P ₂ , and then the main shaft is cooled. 5 through an internal flow path formed inside. As a result, the coolant L is supplied to the main shaft 5, the bearing 1
The shaft cooling 32 is performed by flowing through the inner ring sides 0 and 11 and the inner peripheral side of the built-in motor 12.

After the axial cooling 32 has been performed, the flow path is branched into two branches, and one branch flow path 30a is provided with a mechanical switching valve 33. Mechanical switching valve 33
Is provided in the main shaft 5 and has a tool 6 having an internal flow path.
Is opened when it is mounted on the tool mounting portion at the tip of the spindle 5. The coolant that has passed through the mechanical switching valve 33 is
The DIN through coolant (or center through coolant) 38 is jetted to the cutting portion 13 on the table 7.

When the tool 6 is not mounted on the main shaft 5,
Alternatively, when the tool 6 has no internal flow path, the mechanical switching valve 33 is closed, so that the internal pressure of the axial-side circulation flow path 30 increases, and the check valve 34 of the other branch flow path 30b. Opens. As a result, the coolant L that has undergone the shaft center cooling 32 passes through the check valve 34 and passes through the dirty tank 20.
Will be collected.

[0034] In the outer cylinder side circulating passage 31, the coolant L clean tank 21 is continuously withdrawn by the outer cylinder flow channel pump P _3, internal flow passage formed inside the main shaft support 9 Through the outer ring side of the bearings 10 and 11 and the outer peripheral side of the built-in motor 12 to perform outer cylinder cooling 35. On the downstream side of the outer cylinder cooling 35, there are branch flow paths 31a and 31b that are divided into two branches. One branch channel 31
a is provided with a check valve 35, and the other branch flow path 31
b is provided with an electromagnetic switching valve 36.

If the electromagnetic switching valve 36 is open, the coolant L that has performed the outer cylinder cooling 35 is collected in the dirty tank 20 through the electromagnetic switching valve 36. On the other hand, the electromagnetic switching valve 3
When the internal pressure of the outer cylinder side circulation channel 31 is increased by closing the valve 6, the check valve 35 is opened. Then, the coolant L flows through the check valve 35 in the open state, and is ejected as a flood coolant 39 from the ejection portion provided at the tip of the spindle support member 9 to the cutting portion 13. In this manner, the coolant that has flowed through one or both of the mechanical switching valve 33 and the check valve 35 and jetted to the cutting portion 13 is dirty from the cutting region through the recovery path 37 provided in the bed 2 or the like. Collected in the tank 20.

FIG. 4 is a graph showing the operation of the cooling device 22, the coolant temperature _{Tc, and the} like. The horizontal axis shows time,
The vertical axis indicates the operating state and the temperature of the start and stop of the cooling device 22 and the temperature. The cooling device 22 repeatedly starts up under the condition of the following expression (1) and stops under the condition of the following expression (2). _{T c> T a (T a} = T s + T v + ΔT) ......... (1) T c <T b (T b = T s + T v) ......... (2)

That is, the cooling device 22 is connected to the graph 40 of FIG.
As shown in, start the coolant temperature T _c is raised to start the temperature T _a, the coolant temperature T _c is stop temperature T _b
Stops when descending. Thereby, the temperature of the coolant L in the clean tank 21 is adjusted. Start temperature T _a value obtained by subtracting the stop temperature T _b from is at a temperature ΔT of the control range. The control range temperature ΔT and the shift temperature T _v are values determined by setting, and the control range temperature ΔT is a value (for example, 0.2 ° C.) specific to the machine tool. Shifting the temperature T _v is the temperature for arbitrarily shifting the temperature i.e. the coolant temperature T _c of the controlled object with respect to the reference temperature T _s, the positive value of the negative or zero is used. The graph of FIG. 4 shows a case where the shift temperature T _v is a positive value.

Next, the operation of the MC 1 according to the present invention will be described. 1 to 4, Start MC1, pump P ₁ to P _3, the filtration device 26, activates the cooling device 22, respectively coolant in the axial side circulation flow path 30 and the outer cylinder side circulation flow path 31 Rinse and circulate. Detecting the coolant temperature T _c by coolant temperature sensor S _1, for detecting the reference temperature T _s by the reference temperature sensor S _2. Then, these detected temperature T _c, the controller respective signals T _s is input 2
3 controls the cooling device 22 to control the temperature of the coolant L.

If the tool 6 has an internal flow path, the coolant that has flowed through the axial-side circulation flow path 30 and cooled the shaft center 32 is ejected to the cutting section 13 through the mechanical switching valve 33. . At this time, the coolant that has flown through the outer cylinder side circulation flow path 31 and cooled the outer cylinder 35 is returned to the dirty tank 20 by opening the electromagnetic switching valve 36, but the electromagnetic switching valve 36 is closed to increase the internal pressure. Then, the gas may be ejected from the check valve 35 to the cutting portion 13.

When the tool 6 has no internal flow path,
The coolant that has flowed through the axial-side circulation passage 30 passes through the check valve 34 due to an increase in the internal pressure, and the dirty tank 20
Flows to In this case, if necessary, the electromagnetic switching valve 36
Is closed, the internal pressure is increased, and the coolant flowing through the outer cylinder side circulation channel 31 can be ejected to the cutting portion 13 as the flood coolant 39 via the check valve 35.

Next, the main shaft 5 is rotated, and the cutting of the workpiece 8 by the tool 6 is started. In the case of a conventional machine tool in which a coolant tank is installed outside the fuselage, the temperature of the fuselage does not match the temperature of the coolant at the start of this cutting, so the coolant with a temperature difference And the machine body is thermally deformed, and the processing accuracy is reduced. On the other hand, in the present invention, since the clean tank 21 having a large capacity is built in the bed 2,
Heat exchange is always performed between the clean tank 21 and the bed 2.

Since the entire body 14 has substantially the same temperature due to heat conduction from the bed 2, the temperature of the entire body 14 and the temperature of the coolant L in the clean tank 21 are equal to M.
Even during the stop of C1, the values almost always match. Therefore, there is almost no temperature difference between the supplied coolant and the entire body 14. As a result, even when the operation of the MC 1 is started and the coolant L in the clean tank 21 is supplied to the machine body 14, the machine body 14 does not thermally deform, so that the workpiece 8 is cut with high machining accuracy from the start of the machining operation. be able to.

[0043] After the machining operation starting, over time, the influence of changes in ambient temperature T, and the bearing 10 and 11, by thermal effects or the like generated by such a built-in motor 12, a reference detected by the reference temperature sensor S ₂ temperature T _s is changed gradually as shown in FIG. The coolant flowing through the axial circulation path 30 and the outer cylinder circulation path 31, respectively, is heated by performing the axial cooling 32 and the outer cylinder cooling 35, and then is cooled.
b, 31b and the like, and are collected in the dirty tank 20. On the other hand, the coolant supplied to the cutting portion 13 is:
In a state further heated by high-temperature chips generated in the cutting section 13, the dirty tank 20 passes through the collection path 37.
Will be collected.

The high-temperature coolant L ₀ collected in the dirty tank 20 is extracted by the transfer pump P ₁ , cleaned by the filtration device 26, and then sent to the clean tank 21 through the pipe 24. The temperature T _c of the coolant flowing through the pipe 24 is detected by a coolant temperature sensor S ₁ , and the signal is sent to the control device 23. On the other hand, the reference temperature T _s
, The signal is sent to the control device 23 is detected by the reference temperature sensor S _2.

The control device 23 uses the reference temperature T _s , the coolant temperature T _c , the control range temperature ΔT, and the shift temperature T _v to calculate the start temperature _Ta and the stop temperature T based on the equations (1) and (2). _b is always calculated (see FIG. 4). When the coolant temperature T _c is higher than the activation temperature T _a (formula (1)), the control device 23 the coolant L in the clean tank 21 is cooled so activates the cooling device 22, the temperature-controlled coolant L is It is supplied to the body 14.

The time to the coolant is cooled coolant temperature T _c is below the stop temperature T _b (Equation (2)), the controller 23 stops the cooling device 22. In this way, by controlling the cooling device 22 to be turned on and off, the temperature of the coolant supplied from the clean tank 21 is controlled to be substantially equal to the predetermined position of the body 14 or the entire temperature.

Since the reference temperature sensor S ₂ is attached to the bed 2, the reference temperature sensor S ₂ is relatively insensitive to the outside air.
Since the mass itself is large, the reference temperature T _s does not change much even if the change in room temperature T. Accordingly, to controlling the coolant temperature T _c based on a reference temperature T _s which are stable, the temperature of the coolant supplied to the body 14, it can be substantially matched to the temperature of the body 14. As a result, the processing accuracy becomes high. In this case, since the reference temperature T _s value is relatively low per se, along with this, also the coolant L in the clean tank 21, tends to be more cooled to a low temperature.

On the other hand, when the reference temperature sensor S ₃ is mounted on the column 3, the mass of the column 3 is smaller than that of the bed 2, and the mounting position of the reference temperature sensor S ₃ is higher than the bed 2. because it is in, the reference temperature T _s easy changes influenced by the outside air. As a result, the starting temperature T _a and the stop temperature T _b is relatively large changes, will also vary the temperature of the coolant L in the clean tank 21, there is a possibility that the machining accuracy is slightly lowered. However, since the temperature of the reference temperature T _s itself is relatively high, the temperature of the coolant L in the clean tank 21 is controlled in a state of high. As a result, it is preferable in that the operation time of the cooling device 22 is shortened and energy is saved.

The above operation, the reference temperature T _s based on machine body or room temperature T, the coolant temperature T _c is a tuning operation to control the temperature of the coolant to tune. On the other hand, when the room temperature T is substantially constant, for example, when the MC 1 is installed in a constant temperature factory or the like, a constant temperature operation can be performed instead of the tuning operation.

[0050] In the constant temperature operation, is stored in advance coolant temperature T _c or reference temperature T _s at the time of starting the operation of the MC1, the temperature T _c or T _s and the shift temperature T _v and stored
Preparative and stop temperature T _b plus controls the cooling device 22 as coolant temperature T _c in the range of the activation temperature T _a plus the control range temperature ΔT to the stop temperature T _b enters. If this constant temperature operation, it is not necessary to perform a calculation for calculating a an activation temperature T _a and the stop temperature T _b continuously, the control is simplified.

As described above, in the present invention, for example, the clean tank 21 is built in the bed 2 by making the inside of the bed 2 itself a clean tank 21, and the stored coolant is constantly brought into contact with the body 14. The temperature of the airframe 14 and the temperature of the coolant L were positively matched. Therefore, even if the coolant is supplied to the body 14 such as the spindle head 4, the temperature of the body 14 is maintained substantially equal to the temperature of the coolant L in the clean tank 21,
Airframe 14 does not undergo thermal deformation.

As a result, MC1 for warming the body 14
Even if the processing operation is started immediately without warming up, high processing accuracy can be obtained from the start of the processing operation. If a clean tank is made of a material having a high thermal conductivity such as an iron plate, and the clean tank is housed inside the bed 2 to increase the contact area between the bed 2 and the clean tank, 2
It has the same effect as the case where the inside itself is a clean tank.

Further, even if the machining operation progresses and the machine body temperature and the room temperature T gradually change, the temperature of the supplied coolant is controlled by the temperature so as to substantially match the temperature of the machine body 14, so that the coolant is always related. Cutting can be performed with high processing accuracy. As a result, in the present invention, the temperature of the coolant can be almost always equal to the temperature of the machine body 14 during the entire machining operation time including the start time of the machining operation, so that the MC1 caused by the temperature difference between the coolant and the machine body is caused. , The processing accuracy can be always improved.

In the present invention, the temperature-controlled coolant L
Accordingly, the cooling of the shaft center 32 of the spindle head 4 and the cooling of the outer cylinder 35 are performed, so that the inner and outer peripheral sides of the heat generating portion can always be sufficiently cooled. Therefore, the temperature difference between each part due to heat generation can be reduced, and thermal displacement of the spindle head 4 can be prevented to perform high-precision cutting.

Since the coolant L flows through the flow path inside the spindle head 4 to cool the bearings 10 and 11, the bearing preload applied to these bearings 10 and 11 can be maintained at an appropriate value. Thereby, troubles such as seizure of the bearings 10 and 11 can be prevented, and a long life of the bearings 10 and 11 and a stable operation at high speed rotation can be realized.

In recent years, a built-in motor built in the spindle device is often used as a spindle drive motor, so it has been necessary to cool this motor to prevent thermal displacement of the spindle device. According to the present invention, the built-in motor 12 can be effectively cooled.

Since the coolant supplied to the cutting portion 13 is also used for cooling the heat generating portion of the spindle head 4, there is no need to separately provide a coolant flow path and a tank separate from the coolant. No special cooling device for the cooling liquid is required. Therefore, the installation area can be made compact by reducing the size of the entire tank in MC1.

Further, since the heat generating portion is cooled by using the water-soluble coolant L having a clean and high cooling efficiency whose temperature is controlled as a medium, excellent cooling performance can be exhibited and high cooling efficiency can be obtained. Since it is not necessary to separately provide a flow path for the coolant in the spindle 5 and the spindle support 9 in the spindle head 4, the manufacture of the spindle 5 and the spindle support 9 becomes easy.

In recent years, from the viewpoint of environmental protection and the like, various types of coolants which are excellent in decay resistance and do not need to be replaced for a long period of time have been developed and sold. Even the coolant does not rot. A major cause of coolant contamination is the incorporation of chips, lubricating oil, and the like.
To be eliminated.

On the other hand, floating substances such as lubricating oil rarely enter the clean tank 21 directly, but if they do so, part of the coolant L in the clean tank 21 is transferred from the guide plate 25 to the dirty tank. Since the overflow always occurs on the side of the clean tank 21, the lubricating oil or the like floating in the coolant L in the clean tank 21 is discharged to the dirty tank 20.

As described above, the filtered and clean coolant L is stored in the clean tank 21 and is supplied to the clean tank 2.
1 is configured to minimize mixing of chips and lubricating oil. Therefore, if an appropriate coolant is used, cleanliness of the clean tank 21 is always maintained, and almost no maintenance work such as cleaning of the clean tank 21 is required, and the maintenance becomes substantially maintenance-free.

Conventionally, when a coolant tank is built in a bed, there has been a problem that the temperature of the coolant in the tank gradually rises and a problem that maintenance work is complicated. Both problems were solved by adopting

Since a large amount of coolant having a large heat capacity is stored in the body 14, even if the room temperature T changes rapidly, the temperature of the coolant in the clean tank 21 does not change so much. As a result, the thermal stability of the fuselage 14 is improved. Since the clean tank 21 is stored in the bed 2,
The center of gravity of the entire MC1 is lowered to suppress vibration, thereby improving machining performance and making the entire MC1 compact. The same reference numerals in the drawings indicate the same or corresponding parts.

[0064]

Since the present invention is constructed as described above, the temperature of the cutting oil is almost always equal to the temperature of the machine body during the entire working time including the starting time of the working operation, and the difference between the two temperatures is caused by the temperature difference between the two. Therefore, it is possible to improve the processing accuracy by preventing thermal displacement of the machine tool.

[Brief description of the drawings]

FIGS. 1 to 4 show an example of an embodiment of the present invention, and FIG. 1 is a schematic front view of a machine tool.

FIG. 2 is a schematic side view of the machine tool.

FIG. 3 is a circuit diagram showing a flow path of a cutting fluid.

FIG. 4 is a graph showing the operation of the cooling device and the temperature of the cutting oil and the like.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Machining center (machine tool) 2 Bed (base) 4 Spindle head (spindle device) 5 Spindle 9 Spindle support 10, 11 Bearing (heat generation part) 12 Built-in motor (heat generation part) 13 Cutting part 14 Body 20 Dirty tank 21 Clean tank 22 Cooling device 23 Control device 26 Filtration device 30 Shaft side cutting oil circulation channel 31 Outer cylinder side cutting oil circulation channel L, L ₀ Cutting oil S ₁ Coolant temperature sensor (cutting oil temperature detecting means) S ₂ standard Temperature sensor (reference temperature detection means) S ₃ Reference temperature sensor (reference temperature detection means) T Room temperature T _c Temperature of cutting fluid T _s Reference temperature

Claims (6)

[Claims] 1. A machine tool which circulates a cutting fluid and supplies it to a cutting portion, wherein the cutting fluid is supplied to the cutting portion and is provided outside the machine tool and is collected and stored. A dirty tank, a clean tank that is built in a base at the lower part of the body, and stores the cutting fluid that has been transferred from the dirty tank and becomes clean; A cutting oil temperature detecting means for detecting a temperature of the cutting oil at a predetermined position before flowing into the machine; a reference temperature detecting means attached to a predetermined portion of the body to detect a reference temperature; and provided in the clean tank. A cooling device for cooling the cutting fluid in the clean tank; the cutting fluid temperature detected by the cutting fluid temperature detecting means; and the reference temperature. A control device that controls the cooling device so that the temperature of the cutting fluid supplied from the clean tank substantially matches the temperature of the airframe based on the reference temperature detected by the detection unit. Machine tool with a built-in clean tank for cutting fluid. 2. The cutting according to claim 1, wherein the cutting oil temperature detecting means detects a temperature of the clean cutting oil flowing out of the dirty tank and flowing into the clean tank. Machine tool with a built-in oil clean tank. 3. The reference temperature detecting means is mounted at a predetermined position on the base such that the influence of a change in room temperature is small and the heat conduction from the cutting fluid inside and outside the clean tank is small. 3. The machine tool according to claim 1, wherein the temperature of the base is detected as the reference temperature. 4. The reference temperature detecting means is mounted at a predetermined position of the body which is located above the base and is susceptible to a change in room temperature, and detects the body temperature at the predetermined position as the reference temperature. A machine tool having a built-in clean tank for cutting oil according to claim 1. 5. The cutting oil supplied from the clean tank passes through an axis-side cutting oil circulation path that passes through the inside of the spindle of the spindle device, and passes through the inside of a spindle support that rotatably supports the spindle. The shaft-side cutting through which the cutting oil flows after the heating oil is cooled by always supplying the coolant to the outer cylinder-side cutting oil circulation flow path to cool the vicinity of the inside and outside of the heating unit of the spindle device. The cutting oil is ejected to the cutting part by opening one or both of an oil circulation passage and the outer cylinder side cutting oil circulation passage. A machine tool with a built-in clean tank for cutting fluid according to the item. 6. The cutting fluid that has flowed out of the dirty tank is cleaned after fine foreign matters are removed by a filtration device, and then flows into the clean tank, where one of the cutting fluids stored in the clean tank is removed. 6. The apparatus according to claim 1, wherein the part constantly overflows the dirty tank, and discharges a floating substance floating in the cutting fluid in the clean tank to the dirty tank. 7. Machine tool with a built-in clean tank for cutting fluid.