JP4827959B2 - Machine tool feed shaft cooling system - Google Patents

Description

  The present invention relates to a feed shaft cooling device for a machine tool driven by a linear motor.

  Patent Document 1 is disclosed as an example of a conventional apparatus to which a moving mechanism using a linear motor is applied. As described in paragraph No. 0006 of Patent Document 1, the invention described in Patent Document 1 provides an apparatus for removing heat generated by a linear motor by cooling a coil of the linear motor. It is aimed. Paragraph 0007 describes the configuration of the invention, that is, “In the present invention, in a linear motor having a coil and a jacket that covers the coil and is supplied with a refrigerant in the internal space, the jacket is divided into an inner side and an outer side. It has a heavy structure, and two types of refrigerants having different properties are allowed to flow through the inner jacket and the outer jacket of the coil. In paragraph 0009, a description for explaining the operation of the invention, that is, “an inert refrigerant is used for the coil inner jacket to prevent damage to the insulating layer on the coil surface. The lack of cooling capacity due to the use of an inert refrigerant having generally poor cooling capacity for the jacket can be compensated by flowing a refrigerant with good cooling efficiency through the outer jacket of the double jacket. According to this, the heat generated from the linear motor coil is absorbed without damaging the insulation layer on the coil surface, eliminating the influence on accuracy, thermal deformation of the structure, measurement error of the laser interferometer, etc. Excellent stage apparatus, exposure apparatus, device manufacturing method, etc. can be provided. "

JP 2001-25227 A

  In Patent Document 1, in order to increase the cooling capacity, the jacket has a double structure of an inner side and an outer side, and the refrigerant supplied to the space between the inner jacket and the outer jacket is surrounded by the inner jacket. A refrigerant having a higher cooling capacity than the refrigerant supplied to the space is supplied, heat generated from the linear motor is absorbed by the refrigerant, and thermal deformation due to the temperature of the structure changing to the high temperature side is prevented. It has become. However, the use of a refrigerant having a high cooling capacity causes a problem that the structure is supercooled and heat deformation occurs due to the temperature of the structure changing to the low temperature side. That is, the structure expands and deforms when the temperature of the structure is higher than the reference temperature, and contracts and deforms when the temperature of the structure is lower than the reference temperature. Since deformation due to lowering is not taken into consideration, thermal deformation of the structure cannot be sufficiently suppressed. For this reason, in order to suppress thermal deformation of the structure and perform high-precision processing, it is necessary to keep the temperature of the structure at a constant temperature.

  An object of the present invention is to provide a cooling device for a feed shaft of a machine tool that can cool a coil portion that is a heat source of a linear motor without overcooling a structure located in the vicinity of the linear motor. To do.

  In order to achieve the above object, according to the present invention, in a feed shaft cooling device for a machine tool driven by a linear motor, a first coolant passage provided in a coil portion of the linear motor and for circulating a coolant. A second coolant passage that is provided in an outer peripheral portion of the linear motor and allows the coolant to flow; and a coolant adjusted to a temperature lower than a body temperature is supplied to the first coolant passage; There is provided a feed shaft cooling device for a machine tool, characterized in that a coolant supply means for supplying a coolant adjusted to the temperature of the machine body is provided in the passage.

  According to the invention, the machine tool has three feed shafts that are respectively driven by a linear motor but are orthogonal to each other, and each feed shaft has the first coolant passage and the second coolant passage. , And the coolant supply means is provided with a feed shaft cooling device for a machine tool that supplies the coolant whose temperature is individually adjusted to each coolant passage of each feed shaft.

  Further, according to the present invention, the machine tool has a thermal deformation preventing means for circulating the liquid filled in the machine main body, and the cooling liquid supply means is the liquid at the center of the machine main body. There is provided a machine tool feed shaft cooling device that detects the temperature of a block immersed therein as the body temperature and adjusts the temperature of the coolant.

  According to the present invention, the air cooled by exchanging heat with the coolant adjusted to a temperature lower than the airframe temperature is supplied to the space around the magnet and the coil portion of the linear motor. A machine feed shaft cooling system is provided.

  According to the present invention, the cooling liquid supply means includes a first liquid temperature adjusting unit that adjusts the temperature of the first cooling liquid, and a second liquid temperature adjustment that adjusts the temperature of the second cooling liquid. And a feed shaft cooling device for a machine tool.

  As described above, according to the cooling device for the feed shaft of the machine tool of the present invention, the coil portion of the linear motor is adjusted to a temperature lower than the body temperature without cooling the outer periphery of the linear motor to a temperature lower than the body temperature. Since it cools with the made refrigerant | coolant, the coil part which is a heat generation source of a linear motor can be rapidly cooled, without overcooling the structure located in the vicinity of a linear motor.

It is sectional drawing which shows the principal part of one Embodiment of the feed shaft cooling device of a machine tool. It is sectional drawing cut | disconnected along the II-II line | wire of FIG. It is sectional drawing cut | disconnected along the III-III line of FIG. It is sectional drawing which shows the mode inside the machine main body filled with the liquid. It is a block diagram of a cooling device.

  The machine tool feed shaft cooling device of the present invention is limited to being applied to a vertical machining center (hereinafter referred to as “vertical M / C”) having a vertical main shaft shown in FIG. 4 of the present specification. The present invention can be applied to a horizontal machining center having a horizontal main shaft having a feed shaft driven by a linear motor, a turning center, and other machine tools.

  A feed shaft cooling device 10 of a machine tool according to the present embodiment is a cooling device that cools linear motors 15, 25, and 35 that drive linear feed shafts X, Y, and Z, and is provided in a movable coil portion 18 of the linear motor. The first coolant passage 17 that circulates the liquid (first coolant) 50 that is adjusted to a temperature lower than the body temperature of the vertical M / C1 and absorbs heat from the movable coil portion 18, and the movable coil A liquid (second liquid) that is provided in a machine body portion that supports the magnet 19 of the linear motor, which is a portion around the portion 18, and is adjusted to a temperature approximately equal to the machine body temperature to prevent the machine body from being overcooled. A cooling liquid supply means for adjusting the temperature of the liquid 50 passing through the first cooling liquid passage 17 and the temperature of the liquid 51 passing through the second cooling liquid passage 21; It has. The coolant supply means adjusts the temperature of the liquid 50 passing through the first coolant passage 17 and adjusts the temperature of the liquid 51 passing through the second coolant passage 21 and adjusts the temperature of the liquid 51 passing through the second coolant passage 21. Part 23. Thereby, the movable coil part 18 of a linear motor can be forcedly and intensively cooled, without the surrounding part of the movable coil part 18 being cooled to temperature lower than body temperature. That is, the second coolant passage 21 acts to prevent the heat from being transferred to the outer peripheral portion even when the movable coil portion 18 is supercooled.

  FIG. 1 is a diagram for explaining an embodiment of a feed shaft cooling device of the present invention. The illustrated feed shaft is represented by a vertical feed shaft Y of the vertical M / C1 shown in FIG. The Y-axis linear motor 25 is a motor that linearly moves a movable-side moving body 16 (which contacts the table 7) having the movable coil portion 18 with respect to the fixed base 14 (which contacts the bed 4) that supports the magnet 19. It is. The base 14 on the fixed side is a machine body portion having high rigidity, and hits the column 5 on the X axis and the saddle 8 on the Z axis. The movable body 16 on the movable side is a portion that moves along the linear motion guide 26, and corresponds to the saddle 8 on the X axis and the spindle head 9 on the Z axis.

  As shown in FIG. 1, in this embodiment, a pair of opposing magnets 19 is provided on the base 14 via a magnet support portion 14b. One surface of the plate-like magnet 19 is fixedly supported on the inner surfaces of the pair of magnet support portions 14b. A movable coil portion 18 that is suspended from the lower surface of the moving body 16 is disposed between a pair of opposing magnets 19. The movable coil portion 18 includes a coil support portion 18a that is suspended from the center of the movable body 16 in the width direction, and electromagnetic coils 18b that are fixed to the left and right sides of the coil support portion 18a. The base 14 having a pair of magnets 19 and the moving body 16 having a pair of electromagnetic coils 18b are symmetrical. Since the magnets 19 are configured by alternately arranging magnets 19 having different polarities in the feed axis direction, by changing the current flowing through the electromagnetic coil 18b, the magnets 19 are separated between the individual magnets 19 having different polarities and the electromagnetic coil 18b. Thus, a driving force for moving the moving body 16 in the feed axis direction is generated. As a result, the moving body 16 is guided by the linear motion guide 26 and can move at high speed.

  In general, a feed shaft using a linear motor has a problem that the temperature around the electromagnetic coil increases due to heat generated from the electromagnetic coil. When the temperature of the machine main body becomes high, the machine main body is thermally expanded (thermal deformation), and the processing accuracy is lowered. In such a case, the electromagnetic coil of the linear motor is cooled. Similarly, in the feed shaft cooling device 10 of the present embodiment, the first cooling fluid passage 17 through which the liquid 50 flows is provided in the electromagnetic coil 18b as a configuration for removing heat from the electromagnetic coil 18b. However, when the electromagnetic coil 18b is cooled, the structure portion existing around the electromagnetic coil 18b is also cooled at the same time, and the base 14 and the moving body 16 may be deformed by overcooling. In view of this, the feed shaft cooling device 10 of the present embodiment is provided with a magnet support portion 14b and a moving body 16 that support the magnet 19 in order to prevent overcooling of the base 14 and the moving body 16 that are portions around the electromagnetic coil 18b. A second coolant passage 21 is provided for flowing the liquid 51 adjusted to substantially the body temperature.

Hereinafter, the feed shaft cooling device 10 of this embodiment will be described in detail.
As shown in FIG. 1, the first coolant passage 17 through which the liquid 50 adjusted to a temperature lower than the body temperature flows passes through the inside of the pair of electromagnetic coils 18 b. Thereby, a pair of electromagnetic coil 18b is forcedly cooled. The second coolant passage 21 through which the liquid 51 adjusted to a temperature substantially equal to the body temperature passes through the magnet support portion 14 b of the base 14 and the wall portion of the moving body 16. The heat flow between the outside and the inside of the second coolant passage 21 is blocked by the second coolant passage 21, and the base 14 and the moving body 16 are prevented from being overcooled.

  FIG. 2 shows a thick coolant passage 17d and a narrow coolant passage 17a as the first coolant passage 17 for cooling the electromagnetic coil 18b. The liquid 50 adjusted to a temperature lower than the airframe temperature flows into the coolant passages 17a and 17d from one inlet, and the liquid 50 that has absorbed heat flows out from the other outlet. For example, an oily liquid can be used as the liquid 50.

  FIG. 3 shows the second coolant passage 21 that passes through the magnet support portion 14 b of the base 14 and the wall portion of the moving body 16 together with the telescopic cover 2. The telescopic cover 2 is a cover having a structure in which the overlapped sheet metal members extend and contract in the feed axis direction, and slides with the moving body 16 while covering the linear motor to prevent intrusion of dust and adhesion of dust to the linear motor. The liquid 51 adjusted to a temperature substantially equal to the temperature of the machine body flows into the second coolant passage 21 from one inlet and flows out from the other outlet. The cooled air 52 is introduced into the moving body 16 and ejected from below the moving body 16 into the gap of the linear motor, and the air 52 that has absorbed the heat of the electromagnetic coil 18b is discharged from the open ends of the both ends of the telescopic cover 2. Then, air stagnation in the internal space surrounded by the telescopic cover 2 is removed. As the liquid 51, the same oily liquid 50 as the liquid 50 flowing in the first coolant passage 17 can be used except that the temperature is different.

  FIG. 4 shows a vertical M / C1 having linear feed axes X, Y, and Z driven by linear motors 15, 25, and 35 as an embodiment of a machine tool to which the feed shaft cooling apparatus of the present invention is applied. It is shown. The vertical M / C 1 includes a table 7 supported so as to be horizontally movable with respect to the bed 4, a saddle 8 supported so as to be movable in a direction perpendicular to the paper surface with respect to the column 5, and up and down with respect to the saddle 8. And a spindle head 9 supported so as to be movable. The saddle 8 is driven by an X-axis linear motor 15, the table 7 is driven by a Y-axis linear motor 25, and the spindle head 9 is driven by a Z-axis linear motor 35. Each of the three linear motors 15, 25, and 35 is individually cooled by the cooling device 10.

  The vertical M / C 1 has thermal deformation preventing means for circulating the liquid 6 filled in the bed 4 and the column 5. The thermal deformation prevention means includes a pump 27 that fills and circulates the liquid 6 in the cavities inside the bed 4 and the column 5, and a circulation time control unit that starts and stops the liquid circulation unit to control the circulation time of the liquid 6. 28. By means of the thermal deformation prevention means, the temperature of each part of the machine body can be kept substantially uniform even if there is a difference in temperature distribution at room temperature. Further, the machine main body includes a metal block 11 that is immersed in the liquid 6 and has a temperature sensor 11a therein. The block 11 is supported by a stay 12 made of a material having low thermal conductivity and having a small mounting area so as not to be affected by heat from the machine body 3. Further, the block 11 is immersed in the liquid 6 so as to be located in the vicinity of the center position of the machine body at the substantially center between the top and bottom of the bed 4 and the column 5, and approximately the center of the left and right and front and back of the column 5. By positioning the temperature sensor 11 in the vicinity of the center position of the machine body, the averaged temperature of the machine body can be detected as the machine temperature. Based on the airframe temperature detected by the temperature sensor 11a, the temperature of the liquid 50 in the first coolant passage 17 and the temperature of the liquid 51 in the second coolant passage 21 are determined, and the temperature of the machine body is under a certain condition. Thus, high-precision processing is performed. The airframe temperature can be set to room temperature as an example. Further, in a machine tool in which the machine main body is not filled with liquid, an average value of temperature sensors attached to several places of the machine main body may be used as the body temperature. The temperature of the liquid 50 in the first coolant passage is set to a value that is a predetermined temperature lower than the body temperature.

  FIG. 5 shows a block diagram of the feed shaft cooling device 10 of the present embodiment. The linear motors 15, 25, and 35 of the three linear feed axes X, Y, and Z serve as first coolant passages 17a and Y for the X axis as first coolant passages through which the liquid 50 having a temperature lower than the body temperature passes. A first coolant passage 17b for the shaft and a first coolant passage 17c for the Z-axis are provided. The temperature of the liquid 50 passing through the first cooling fluid passage 17a for the X axis, the first cooling fluid passage 17b for the Y axis, and the first cooling fluid passage 17c for the Z axis is determined by the X axis first liquid temperature adjusting unit 22a, The Y-axis first liquid temperature adjusting unit 22b and the Z-axis first liquid temperature adjusting unit 22c can be individually set to different temperatures at a temperature lower than the body temperature. This temperature adjustment is performed by a temperature sensor 31a for detecting the temperature of each return liquid in the first coolant passage 17a for the X axis, the first coolant passage 17b for the Y axis, and the first coolant passage 17c for the Z axis. The temperatures detected by 31b and 31c are taken in by the X-axis first liquid temperature adjusting unit 22a, the Y-axis first liquid temperature adjusting unit 22b, and the Z-axis first liquid temperature adjusting unit 22c, respectively, and are detected by the temperature sensor 11a. The temperature is controlled to be lower by a predetermined value. Thereby, the cooling capacity of the linear motors 15, 25, and 35 can be changed according to the magnitude of the load.

  Further, the three linear feed axes X, Y, and Z are based on the air temperature detected by the air temperature sensor 11a and the temperature of the second coolant detected by the tank temperature sensor 13 of the second coolant. A common second coolant passage 21 is provided for flowing the liquid 51 adjusted to a temperature substantially equal to the airframe temperature by the second liquid temperature adjusting unit 23 common to the axes. The liquid 51 adjusted to a temperature substantially equal to the body temperature and the liquid 50 having a temperature lower than the body temperature are partitioned by the partition plate 30 in the tank. Liquids 50 and 51 are supplied to the respective coolant passages 17a, 17b, 17c and 21 by a pump 20.

  The liquid 50 in the tank is circulated to the heat exchanger 24 by the pump 20. The air supplied from the air supply source 29 is cooled by the heat exchanger 24 and is ejected into the space near the linear motor of each feed shaft to remove air stagnation and to cool the linear motor and remove dust. .

  As described above, according to the feed shaft cooling device 10 of the machine tool of this embodiment, the linear motors 15, 25, 35 of the linear motors 15, 25, 35 are not supercooled without overcooling the structures located in the vicinity of the linear motors 15, 25, 35. The heat generated by the electromagnetic coil 18b can be removed. Thereby, a deformation | transformation of a machine tool is suppressed and a highly accurate process can be performed.

1 Vertical M / C
DESCRIPTION OF SYMBOLS 10 Feed shaft cooling device 11 Block 13 Tank temperature sensor 14 Base 14b Magnet support part 15 X-axis linear motor 16 Moving body 17 1st cooling fluid path 18 Movable coil part 18b Electromagnetic coil 19 Magnet 21 2nd cooling fluid path 22 First liquid temperature adjustment unit 23 Second liquid temperature adjustment unit 25 Y-axis linear motor 35 Z-axis linear motor

Claims (5)

In a machine tool feed shaft cooling device driven by a linear motor,
A first coolant passage that is provided in the coil portion of the linear motor and allows the coolant to flow;
A second coolant passage provided in an outer peripheral portion of the linear motor for circulating the coolant;
A coolant supply means for supplying a coolant adjusted to a temperature lower than the airframe temperature to the first coolant passage, and a coolant supply means for supplying a coolant adjusted to the airframe temperature to the second coolant passage;
A machine tool feed shaft cooling device comprising:   The machine tool has three feed shafts that are respectively driven by a linear motor but are orthogonal to each other. Each feed shaft is provided with the first coolant passage and the second coolant passage, and the coolant supply The feed shaft cooling device for a machine tool according to claim 1, wherein the means supplies the coolant whose temperature is individually adjusted to each coolant passage of each feed shaft.   The machine tool has a thermal deformation prevention means for circulating the liquid filled in the machine body, and the cooling liquid supply means is a temperature of a block immersed in the liquid at a central portion of the machine body. The machine tool feed shaft cooling device according to claim 1, wherein the temperature of the coolant is adjusted by detecting the temperature as the machine temperature.   4. The air cooled by exchanging heat with the coolant adjusted to a temperature lower than the temperature of the airframe is supplied to a space existing around the magnet and the coil portion of the linear motor. The feed axis cooling device for the machine tool according to the item.   5. The cooling liquid supply unit according to claim 1, further comprising: a first liquid temperature adjusting unit that adjusts a temperature of the first cooling liquid; and a second liquid temperature adjusting unit that adjusts the temperature of the second cooling liquid. The machine tool feed shaft cooling apparatus according to any one of the preceding claims.

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