JP2007245286A - Device for cooling main spindle of machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To furthermore uniformly cool the whole of a main spindle provided inside a main spindle casing of a machine tool. <P>SOLUTION: In the main spindle casing 9 of a machining center, a main spindle cooling cylinder 60 is closely fixed inside a housing 25. A closed space formed by multiple-thread groove portions formed on the main spindle cooling cylinder 60 and the inside peripheral surface of the housing 25 functions as a first cooling passage 53 and a second cooling passage 54 for making cooling air flow from an air supplying portion 100. The first cooling passage 53 and the second cooling passage 54 are formed so as to have a multiple-thread shape along the axial direction of a main spindle 27, and are formed at an interval so as not to overlap with each other. In the first cooling passage 53, the cooling air flows from the rear end side of the main spindle 27 toward its front end side. In the second cooling passage 54, the cooling air flows from the front end side of the main spindle 27 toward its rear end side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a spindle cooling device for a machine tool that cools a spindle provided inside a spindle of the machine tool.

  Conventionally, in a machining center which is an example of a machine tool, a workpiece (work) is machined by a tool attached to a spindle (for example, “boring”, “milling”, “drilling”, “cutting”, etc.) Has been given. And in order to rotate the tool attached to the main shaft by the power of the main shaft motor, a driving system is used in which a spindle provided inside the main shaft is connected to the main shaft motor for rotation.

  In such a machine tool, in order to maintain the machining accuracy, it is necessary to suppress an increase in the temperature of the spindle so that an error due to thermal displacement does not occur. Therefore, in a conventional machine tool, a cooling medium such as water or air is supplied into the main shaft, and the cooling medium flows through a spiral cooling path provided inside the main shaft, thereby cooling the heat generation of the spindle. Is known (see, for example, Patent Document 1).

Further, the spindle is rotatably supported in the housing of the main shaft, and a cooling path for cooling the spindle from the inside is provided, and a multiple helix such that the coolant reciprocates along the spindle axis in the cooling path. A groove. As a result, since the coolant flowing through the cooling path reciprocates along the spindle axis direction, a spindle cooling device that can cool the spindle uniformly in the axial direction is known (for example, see Patent Document 2).
Japanese Utility Model Publication No. 64-50036 JP-A-8-71888

  However, in a conventional machine tool, when a cooling medium is supplied to a helical cooling path provided inside the main shaft, the heat generated by the spindle is gradually absorbed as the cooling medium flows in the cooling path. It will be warmed up. Then, the part closer to the inlet of the cooling path to which the cooling medium is supplied has a higher cooling effect by the cooling medium, while the part closer to the outlet of the cooling path from which the cooling medium is discharged has a lower cooling effect by the cooling medium. . Therefore, in a conventional machine tool, the spindle is cooled by the cooling medium flowing in the cooling path, but unevenness occurs to the extent that it is cooled by the part of the spindle, and it is difficult to cool the entire spindle uniformly. There was a problem.

  SUMMARY An advantage of some aspects of the invention is to provide a spindle cooling device for a machine tool that can cool the entire spindle provided inside the spindle of the machine tool more uniformly.

  To achieve the above object, a spindle cooling device for a machine tool according to a first aspect of the present invention includes a spindle rotatably supported through a bearing inside a housing, and a cooling medium for cooling the spindle. A cooling medium supply means for supplying, a plurality of cooling paths which are flow paths of the cooling medium provided in the outer peripheral direction of the spindle, and the cooling medium from the outside of the housing to one end side of the cooling paths, respectively A spindle cooling device for a machine tool, comprising: a plurality of cooling medium inflow portions for inflowing; and a plurality of cooling medium outflow portions for allowing the cooling medium to flow out from the other end side of the plurality of cooling paths to the outside of the housing. At least one of the plurality of cooling paths is a flow path through which the cooling medium flows from one end side to the other end side of the spindle. , The cooling medium toward the one end side from the other end of the spindle, characterized in that a flow path for flowing.

  The spindle cooling device for a machine tool according to a second aspect of the present invention has the configuration according to the first aspect, wherein the plurality of cooling paths are formed in a multiple spiral shape along the axial direction of the spindle. The cooling paths are formed at intervals so as not to overlap each other.

  According to a third aspect of the present invention, there is provided a spindle cooling device for a machine tool according to the first or second aspect, wherein at least one of the plurality of cooling paths is configured to receive the cooling medium in the cooling path. It is characterized in that each flow passage area is gradually increased from the portion toward the cooling medium outflow portion of the cooling passage.

  According to a fourth aspect of the present invention, there is provided a spindle cooling device for a machine tool according to any one of the first to third aspects, wherein the spindle is housed inside the housing. A plurality of multiple spiral grooves are formed along the axial direction on the outer surface of the spindle cooling member, and the plurality of cooling paths are formed between the spindle cooling member and the housing. It is formed in a gap.

  According to a fifth aspect of the present invention, there is provided a spindle cooling device for a machine tool according to the fourth aspect, in addition to the configuration according to the fourth aspect, wherein the plurality of cooling passages flow in the gap between the spindle cooling member and the housing. A plurality of packing members for preventing leakage of the cooling medium are respectively provided along the plurality of cooling paths.

  In addition to the configuration of the invention according to any one of claims 1 to 5, the spindle cooling device for a machine tool of the invention according to claim 6 has a tool attached to and detached from one end of the spindle, A motor is connected to the other end of the spindle, and a workpiece is processed by rotating a tool fitted to the spindle by the motor. A flow path of the cooling medium for allowing the cooling medium to flow in from one end side or the other end side of the spindle, respectively, and the plurality of cooling medium outflow portions pass the cooling medium from the other end side or one end side of the spindle. It is the flow path of the said cooling medium for each flowing out, It is characterized by the above-mentioned.

  According to a seventh aspect of the present invention, there is provided a spindle cooling device for a machine tool, in addition to the configuration of the sixth aspect of the invention, wherein one end of the spindle has an inner peripheral surface of a ring-shaped lid that prevents foreign matter from entering. And at least one of the plurality of cooling medium outflow portions supplies the cooling medium to a gap between an outer peripheral surface of one end of the spindle and an inner peripheral surface of the lid, The cooling medium is discharged through a gap formed at one end of the spindle.

  In addition to the configuration of the invention according to claim 6 or 7, the spindle cooling device for a machine tool of the invention according to claim 8 is characterized in that the cooling medium supply means is based on the amount of current supplied to the motor. Controlling at least one of a supply amount and a supply pressure of the cooling medium.

  According to a ninth aspect of the present invention, there is provided a spindle cooling apparatus for a machine tool according to the sixth aspect, in addition to the configuration of the sixth aspect of the present invention. The cooling medium supply means includes a predetermined time during the operation of the machine tool and after the operation stop, and a predetermined time during the injection of the coolant liquid by the tool cleaning means and after the injection stop. The cooling medium is supplied to at least one of them.

  In addition to the configuration of the invention according to any one of claims 6 to 9, the spindle cooling device for a machine tool of the invention according to claim 10 is characterized in that the cooling medium supply means is based on the temperature of the spindle. It is characterized by controlling at least one of the supply amount and supply pressure of the cooling medium.

  In the spindle cooling device for a machine tool according to the first aspect of the present invention, a plurality of cooling media are provided in the outer peripheral direction of the spindle for cooling the spindle rotatably supported on the inner peripheral surface of the housing via a bearing. At least one of the plurality of cooling paths is a flow path through which the cooling medium flows from one end side to the other end side of the spindle, and the rest of the plurality of cooling paths is This is a flow path through which the cooling medium flows from the other end side of the spindle toward the one end side. Therefore, even if the temperature of the cooling medium flowing in the plurality of cooling paths gradually increases in the flow direction, the cooling medium flowing in the plurality of cooling paths flows in opposite directions, so that the machine tool The entire spindle provided inside the main shaft can be cooled more uniformly.

  Further, in the spindle cooling device for a machine tool according to the second aspect of the invention, in addition to the effect of the first aspect, the plurality of cooling paths are formed in a multiple spiral shape along the axial direction of the spindle. The cooling paths are formed at intervals so as not to overlap each other. Therefore, a plurality of cooling paths having different flow directions can be formed on the entire circumference of the spindle, and the entire spindle can be uniformly cooled from the outer circumferential direction.

  Further, in the spindle cooling device for a machine tool according to the third aspect of the present invention, in addition to the effect of the first or second aspect, at least one of the plurality of cooling paths is changed from the cooling medium inflow portion to the cooling medium outflow portion. Each channel was formed so that its channel area gradually increased. Therefore, even if the temperature of the cooling medium flowing in the plurality of cooling paths gradually increases in the flow direction, the contact area of the cooling medium gradually increases in the flow direction, so that the entire spindle is uniform. Can be cooled to.

  Further, in the spindle cooling device for a machine tool according to a fourth aspect, in addition to the effect of the third aspect, a plurality of multiple helical grooves are formed in the housing along the axial direction thereof. A spindle cooling member that houses the spindle is provided, and a plurality of cooling paths are formed in the gap between the spindle cooling member and the housing. Therefore, if a spindle cooling member is provided inside the housing, a plurality of cooling paths for cooling the spindle can be formed.

  Further, in the spindle cooling device for a machine tool according to the fifth aspect of the present invention, in addition to the effect of the fourth aspect of the invention, leakage of the cooling medium flowing in the plurality of cooling paths is provided in the gap between the spindle cooling member and the housing. A plurality of packing members are provided along the plurality of cooling paths. Therefore, leakage of the cooling medium flowing through the plurality of cooling paths can be reliably prevented, and the spindle cooling effect by the cooling medium can be improved.

  In addition, in the spindle cooling device for a machine tool according to the sixth aspect of the invention, in addition to the effect of the invention according to any one of the first to fifth aspects, the machine tool is provided with a motor connected to the other end of the spindle. A workpiece is machined by rotating a tool fitted to one end of a spindle, and a plurality of cooling medium inflow portions are used to inject the cooling medium from one end side or the other end side of the spindle, respectively. The cooling medium flow path is a cooling medium flow path for allowing the cooling medium to flow out from the other end side or one end side of the spindle. Therefore, a cooling medium for cooling the spindle can be appropriately introduced from the outside of the housing from the other end of the spindle, and can be appropriately discharged from the one end of the spindle to the outside of the housing.

  In the spindle cooling device for a machine tool according to the seventh aspect of the invention, in addition to the effect of the invention according to the sixth aspect, one end of the spindle is rotatably supported on the inner peripheral surface of the lid. At least one of the cooling medium outlets supplies the cooling medium to a gap between the outer peripheral surface of one end of the spindle and the inner peripheral surface of the lid, and the cooling medium passes through a gap formed at one end of the spindle. Is discharged. Therefore, since the cooling medium that has flowed through the cooling path can be discharged from the gap formed at one end of the spindle, foreign matter can be purged from one end of the spindle.

  Further, in the spindle cooling device for a machine tool according to the eighth aspect of the present invention, in addition to the effect of the sixth aspect of the present invention, the supply amount and supply pressure of the cooling medium based on the amount of current supplied to the motor. Control at least one of Therefore, it is possible to appropriately adjust the supply amount and supply pressure of the cooling medium according to the heat generation amount of the spindle that increases and decreases with the drive amount of the motor.

  Further, in the spindle cooling device for a machine tool according to the ninth aspect of the invention, in addition to the effect of the invention according to any one of the sixth to eighth aspects, a predetermined time during and after the operation of the machine tool, and coolant liquid The cooling medium is supplied only during at least one of the predetermined time after the injection and the stop of the injection. Therefore, it is possible to appropriately adjust the supply timing of the cooling medium corresponding to the time when the operation of the machine tool and the cleaning operation of the tool that are easily heated by the spindle are executed.

  In the spindle cooling device for a machine tool according to the tenth aspect, in addition to the effect of the invention according to any one of the sixth to ninth aspects, at least the supply amount and supply pressure of the cooling medium based on the temperature of the spindle. Control one. Therefore, the supply amount and supply pressure of the cooling medium can be appropriately adjusted based on the temperature of the spindle.

  Hereinafter, a machining center 1 according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view of the machining center 1. FIG. 2 is an overall perspective view of the machining center 1 excluding the splash cover 3. FIG. 3 is a front view of the machining center 1 centering on the tool change mechanism 20 and the spindle head 7.

  First, the overall configuration of the machining center 1 will be described. As shown in FIG. 1, the machining center 1 moves a workpiece (not shown) and a tool 6 (see FIG. 3) relative to each other to perform desired machining (for example, “boring”, “milling”) on the workpiece. It is a machine tool that can perform cutting, drilling, cutting and the like. The machining center 1 includes a machine body that processes a workpiece, a bed 2 that serves as a base of the machine body, a box-shaped splash cover 3 that is provided on the bed 2 and surrounds the periphery of the machine body. It is mainly composed.

  As shown in FIG. 2, the bed 2 is an iron base, and leg portions 2a are respectively provided at the lower four corners thereof, and these four leg portions 2a are installed on a floor surface of a factory or the like. Thus, the machining center 1 is installed at a predetermined location. Furthermore, the core part of the bed 2 is so-called cut-out molding (frame structure with ribs) in order to reduce weight and increase strength.

  As shown in FIG. 1, the splash cover 3 is formed in a substantially rectangular parallelepiped box shape, and a machining area in which a workpiece is machined by a machine body is provided inside thereof. On the front surface of the splash cover 3, slide type opening and closing doors 4 and 5 for opening and closing the opening are provided. In addition, glass windows 4a and 5a are provided in the approximate center of the doors 4 and 5, respectively, a handle 4b is provided in the vicinity of the right end of the door 4, and in the vicinity of the left end of the door 5. Is provided with a handle portion 5b. Therefore, the openings are opened by opening these handle portions 4b and 5b away from each other. Then, the operator attaches / detaches the workpiece to / from the table 10 disposed inside the splash cover 3 through the opening.

  Although not shown, a maintenance inspection hatch is detachably provided on each of the left and right side wall portions of the splash cover 3. And the splash cover 3 having the above configuration surrounds the periphery of the machine body and protects it from the outside, and blocks the chips discharged from the machine body and splashes of the cutting fluid from scattering to the outside. It prevents the external environment from being polluted.

  On the other hand, on the front right side of the splash cover 3, an operation panel 11 having a substantially rectangular shape in front view for operating the machining center 1 is provided. A keyboard 11a having various keys is provided on the front surface of the operation panel 11, and a CRT (display) 11b for displaying a setting screen or an execution operation is provided above the keyboard 11a.

  Next, the machine body of the machining center 1 will be described. As shown in FIG. 2, the machine body of the machining center 1 is housed inside the splash cover 3, is mounted and fixed on the upper surface of the column seat portion 17 a of the bed 2, and extends substantially vertically upward. A prismatic column 17b, a spindle head 7 provided so as to be movable up and down along the front surface of the column 17b, a spindle 9 projecting vertically downward from the lower front side of the spindle head 7, and a right side of the spindle head 7. A tool exchange mechanism (ATC) 20 for exchanging a tool 6 (described later) attached to the tip of the main shaft 9 with another tool 6, a table 10 provided on the upper portion of the bed 2 for detachably holding a workpiece, and a column A control panel 19 is provided mainly on the back side of 17b and incorporates each device such as a power supply device and a control board. A control device (not shown) that controls the machining center 1 is disposed inside the control panel 19.

  A pair of guide rails (not shown) extending in the vertical direction and guiding the spindle head 7 are fixed in the vertical direction on the front surface of the column 17b. A Z motor (not shown), which is a servo motor, is provided on the upper surface of the column 17b, and a feed screw (not shown) extending below the Z motor is selectively driven in the forward and reverse directions. Thus, the spindle head 7 moves in the vertical direction.

  A spindle 9 corresponding to a machining axis is rotatably mounted on the spindle head 7 and a spindle motor 8 for rotating the spindle 9 is provided at the top. A tool 6 (described later) is detachably attached to the tip of the main shaft 9, and the tool 6 is rotated by rotating the main shaft 9 by the main shaft motor 8, so that a workpiece fixed on the table 10 is processed. It has become.

  On the other hand, a table 10 is disposed below the main shaft 9. The table 10 has a work detachably fixed thereto, and is controlled to move in the X-axis direction (left-right direction) and the Y-axis direction (depth direction) by an X motor and a Y motor (not shown) that are servo motors. . A substantially rectangular parallelepiped support base 12 is provided below the table 10, and a pair of X-axis feed guides (not shown) extending along the X-axis direction are provided above the support base 12. Thus, the table 10 is movably supported on the X-axis feed guide. Further, the support 12 is supported on a pair of Y-axis feed guides extending along the longitudinal direction of the bed 2 so as to be movable. In this state, the table 10 is moved in the X-axis direction along the X-axis feed guide by the X motor provided on the bed 2, and the Y-axis feed is also provided by the Y motor provided on the bed 2. It moves in the Y-axis direction along the guide.

  As shown in FIG. 3, the tool change mechanism 20 includes a tool magazine 30 having a substantially oval shape in side view for storing a plurality of tool holders 13 to which the tools 6 are attached, and a tool holder 13 attached to the spindle 9. And a tool change arm 40 for gripping and transporting the tool holder 13 and the other tool holder 13.

  The tool exchange arm 40 is an arm provided with gripping portions 41 and 41 capable of gripping the tool holder 13 at both ends at a lower end portion of a cylindrical arm turning shaft 43 that is rotatably and vertically movable. The part 42 is configured to be fixed. The arm turning shaft 43 is parallel to the Z-axis direction, and the arm portion 42 is rotatable about the arm turning shaft 43. A tool change motor 24 is provided above the tool change arm 40, and the tool change arm 40 is turned and moved up and down by the rotational drive of the tool change motor 24.

  In addition, the tool magazine 30 is provided with a transfer mechanism (not shown) in which a plurality of tool pots 31 each capable of storing a plurality of tools 6 are arranged. The attached tool 6 is maintained in a state (stored state) oriented in the lateral direction. A magazine motor 26 is provided on the upper part of the tool magazine 30, and a plurality of tool pots 31 are conveyed by a transfer mechanism by the rotation of the magazine motor 26.

  Further, a split outlet 32 is formed on the lower end side of the tool magazine 30 and the tool pot 31 extends from the retracted state to the state in which the tool 6 faces downward (changeable state) only at the position where the split outlet 32 is formed. It can be turned. A pot lifting mechanism (not shown) that is driven by an air cylinder (not shown) and rotates the tool pot 31 to a retracted state or a replaceable state is disposed at the tool change position.

  When the tool 6 mounted on the spindle 9 is exchanged, the tool exchange arm 40 first turns in a state where the tool exchange arm 40 is raised to the origin, and the tool holder 13 and the spindle 9 on the tool magazine 30 side are turned. The mounted tool holder 13 is gripped by gripping portions 41 and 41, respectively. Next, the tool change arm 40 is lowered and a tool removal operation is performed. Thereafter, the tool change arm 40 is turned, and the tool holder 13 on the spindle 9 side and the tool holder 13 on the tool magazine 30 side are switched. At this time, the tool change arm 40 rotates 180 degrees. Thereafter, the tool change arm 40 is raised, and the tool 6 held by the tool change arm 40 is mounted on the tool pot 31 or the spindle 9 on the tool magazine 30 side. Then, the tool changing arm 40 turns by a predetermined angle, the tool holder 13 is released from the gripping portions 41, 41, and one cycle of the arm turning operation of the tool changing arm 40 is completed.

  Next, the configuration of the spindle head 7 will be described. FIG. 4 is an enlarged side cross-sectional view of the spindle head 7 as viewed from the right direction. FIG. 5 is an enlarged side cross-sectional view of the main shaft 9 as viewed from the right direction. Note that FIG. 4 shows only the housing 25 as a cross-sectional view in order to represent each member arranged on the axis of the spindle head 7 in the center for easy understanding. Further, in FIG. 5, for easy understanding, the upper end of the groove portion 63 (that is, the cooling path 51) formed in the spindle cooling cylinder 60 is positioned at the right end of the front view, and the lower end thereof is positioned at the left end of the front view. It represents a thing.

  As shown in FIG. 4, a spindle motor 8 for rotating and driving a spindle 27 included in the spindle 9 is provided on the spindle head 7. A motor shaft 8 a that is an output shaft that protrudes downward from the lower surface of the spindle motor 8 is coupled to a spindle shaft 27 a that is an input shaft that protrudes upward from a spindle 27 provided inside the spindle 9 via a coupling 50. Are connected. With this configuration, when the motor shaft 8a rotates about the axis by driving the main shaft motor 8, the spindle shaft 27a also rotates through the coupling 50, so the spindle 27 of the main shaft 9 is driven to rotate about the axis.

  Although not shown, the spindle motor 8 has a configuration in which a braking unit and a driving unit are housed in a cylindrical motor frame. The drive unit of the main shaft motor 8 is an inner rotor type induction motor, and the motor shaft 8a is fixed to the inner peripheral surface of the rotor. The braking portion of the spindle motor 8 is a mechanical disc brake that applies a braking force to the motor shaft 8a.

  As shown in FIGS. 4 and 5, the above-described main shaft 9 is provided below the main shaft head 7. The main shaft 9 includes a substantially cylindrical housing 25 that is long in the vertical direction. A spindle cooling cylinder 60 having a vertically long cylindrical shape when viewed from the front is closely fixed inside the housing 25. The spindle cooling cylinder 60 is a cylindrical member that houses the spindle 27 therein and cools the heat generated by the spindle 27, and will be described in detail later.

  A spindle 27 is provided inside the spindle cooling cylinder 60. Specifically, bearing bearings 30 and 31 for rotatably supporting the spindle 27 are provided on the outer peripheral surface of the spindle 27 in the axial direction front end side (lower end side). Similarly, bearing bearings 32 and 33 for rotatably supporting the spindle 27 are provided on the outer peripheral surface on the rear end side (upper end side) in the axial direction of the spindle 27. A vertically long cylindrical outer cylinder 36 that holds the outer periphery of the spindle 27 is provided at a position between the bearing bearings 30 and 31 on the lower end side and the bearing bearings 32 and 33 on the upper end side. The spindle cooling cylinder 60 accommodates the spindle 27 coaxially inside the spindle cooling cylinder 60 so as to closely surround the outer periphery of the spindle 27 provided with the bearing bearings 30 to 33 and the outer cylinder 36. Therefore, the spindle 27 is rotatably supported through the bearing bearings 30 to 33 along the inner peripheral surface of the spindle cooling cylinder 60.

  A holder mounting hole 29 having a tapered inner peripheral surface is bored along the axis of the spindle 27 at the center of the tip of the spindle 27. And the taper-shaped outer peripheral surface of the shank part 14 of the tool holder 13 fits closely with the inner peripheral surface of the holder mounting hole 29. Furthermore, a wide diameter portion 34 that is continuous with the inner peripheral surface of the holder mounting hole 29 and has a slightly larger diameter is provided on the upper portion of the holder mounting hole 29 where the diameter is reduced. The upper portion of the wide-diameter portion 34 is continuous with the inner peripheral surface of the wide-diameter portion 34, and is oil mist (mixed with a small amount of coolant in high-pressure air in a mist shape) toward the tool holder 13 side. A flow path 35 is provided for supplying the liquid. The flow path 35 is provided inside an axial core 28 slidable in the axial direction, and the axial core 28 is urged upward by a disc spring 38 wound around the outer periphery thereof.

  Further, a chuck mechanism portion 37 that holds the pull stud portion 15 formed on the upper end portion of the tool holder 13 via a plurality of steel balls (not shown) is disposed on the lower inner peripheral surface of the flow path 35. . A substantially ring-shaped lid in plan view that holds the tip of the spindle 27 and prevents chips and the like during cutting from entering the bearings 30 and 31 at the tip (lower end) of the housing 25. The body 39 is fixed to the spindle cooling cylinder 60 with a bolt (not shown).

  Further, an air inflow hole 25a, which is a through hole formed perpendicularly from the outer peripheral direction toward the axis, is provided on the side surface of the housing 25 on the rear end side (upper end side) in the axial direction. On the other hand, an air outflow hole 25b, which is a through hole formed perpendicularly from the outer peripheral direction toward the axis, is provided on the side surface of the housing 25 on the front end side (lower end side) in the axial direction. The air inflow hole 25 a and the air outflow hole 25 b are at the upper and lower ends of a spiral groove-shaped sealed space (cooling path 51 in FIG. 7) formed in the gap between the inner peripheral surface of the housing 25 and the outer peripheral surface of the spindle cooling cylinder 60. The details are described later. Note that an air supply unit 100 including a blower fan (not shown) for sending compressed air (cooling air) to the inside of the air inflow hole 25a is formed at a portion where the air inflow hole 25a is formed on the outer peripheral surface of the housing 25. Is provided. In the air supply unit 100, the supply amount and supply pressure of the cooling air are controlled by a control device (not shown) provided in the control panel 19.

  Next, the spindle cooling cylinder 60 will be described. FIG. 6 is a front view of the spindle cooling cylinder 60. As shown in FIG. 6, the spindle cooling cylinder 60 has a cylindrical main body 61 that is vertically long when viewed from the front. A through hole (not shown) that can accommodate the spindle 27 to which the bearings 30 to 33 are attached is formed in the cylindrical body 61 in the axial direction (that is, the vertical direction). Moreover, the flange part 62 protruded in the outer peripheral direction from the perimeter of the opening edge part is formed in the lower end part of the cylindrical main body 61 in front view. The upper surface side of the flange portion 62 is a portion to which the lower end of the housing 25 is joined, and the lower surface side of the flange portion 62 is a portion to which the upper surface of the lid 39 is joined.

  Further, on the outer peripheral surface of the cylindrical main body 61, a groove portion 63 having a substantially semicircular cross-sectional shape formed in a multiple spiral shape along the axial direction is formed. In the present embodiment, the groove portion 63 is formed so as to communicate about five turns along the axial direction, and the groove portion for each turn is referred to as a groove portion 63a, 63b, 63c, 63d, 63e from the upper side in front view. The upper end of the groove 63 (that is, the upper end of the groove 63a) is an air inflow portion 64 into which cooling air, which will be described later, flows, and the lower end of the groove 63 (that is, the lower end of the groove 63e), It is the air outflow part 65 which flows out.

  The groove 63 is formed such that the interval (so-called pitch) at which the adjacent grooves 63 a to 63 e are formed gradually narrows from the air inflow portion 64 toward the air outflow portion 65. That is, the distance (pitch) between the adjacent groove portions 63a to 63e is gradually reduced from the upper side to the lower side of the cylindrical main body 61 as viewed from the front. Therefore, in this embodiment, the gap between the groove 63e and the groove 63d is narrower than the gap between the groove 63d and the groove 63c, and the gap between the groove 63d and the groove 63c is narrower than the gap between the groove 63c and the groove 63b. The gap between the groove 63c and the groove 63b is narrower than the gap between the groove 63b and the groove 63a.

  Further, the groove portion 63 is formed such that the cross-sectional area of the substantially semicircular groove shape in the groove portions 63 a to 63 e for each turn gradually increases from the air inflow portion 64 toward the air outflow portion 65. That is, when viewed from the front, from the upper side to the lower side of the cylindrical main body 61, the substantially semicircular cross-sectional shape of the groove portions 63a to 63e for each turn gradually increases. Therefore, in the present embodiment, the sectional area of the groove 63e is larger than the sectional area of the groove 63d, the sectional area of the groove 63d is larger than the sectional area of the groove 63c, and the sectional area of the groove 63c is larger than the sectional area of the groove 63b. The cross-sectional area of the groove 63b is larger than the cross-sectional area of the groove 63a.

  Here, a cooling structure of the spindle 27 using the spindle cooling cylinder 60 will be described. FIG. 7 is an enlarged side cross-sectional view of the main shaft 9 viewed from the right direction for explaining the flow of cooling air in the first embodiment. FIG. 7 shows only the housing 25 as a cross-sectional view, and the flow of cooling air is indicated by arrows. Further, in FIG. 7, for easy understanding, the upper end of the groove 63 (that is, the cooling path 51) formed in the spindle cooling cylinder 60 is positioned at the right end of the front view, and the lower end thereof is positioned at the left end of the front view. Is shown.

  As shown in FIG. 7, when the spindle cooling cylinder 60 is firmly fixed inside the housing 25, the opening of the groove 63 is closed by the inner peripheral surface of the housing 25. A spiral groove-like sealed space is formed in the gap. The spiral groove-shaped sealed space functions as a cooling air flow path (cooling path 51). In this embodiment, since the groove 63 is formed by communicating about five rounds (grooves 63a to 63e), when the spindle cooling cylinder 60 is closely fixed inside the housing 25, each groove 63a to 63a. The sealed spaces formed in 63e function as cooling paths 51a, 51b, 51c, 51d, and 51e, respectively.

  And the cooling path 51 (cooling paths 51a-51e) has the following characteristics by the shape of the groove part 63 (groove parts 63a-63e) mentioned above. That is, in the cooling path 51, the interval at which the cooling paths 51a to 51e adjacent to each other are formed gradually narrows from the upper end (ie, the air inflow portion 64) toward the lower end (ie, the air outflow portion 65). ing. Further, the flow passage areas (cross-sectional areas of the respective cooling passages) in the cooling passages 51 a to 51 e for each turn gradually increase from the air inflow portion 64 toward the air outflow portion 65. The air inflow portion 64 communicates with the air inflow hole 25a, and the air outflow portion 65 communicates with the air outflow hole 25b.

  With this structure, when the air supply unit 100 supplies cooling air from the outside of the housing 25 to the inside of the air inflow hole 25a, the cooling air flows from the air inflow unit 64 to the air outflow unit 65 in the cooling path 51, The air is discharged out of the housing 25 through the air outflow hole 25b. That is, since the cooling air flowing in the cooling path 51 flows from the upper side to the lower side so that the outer periphery of the spindle 27 turns around the spindle 27, the cooling air flows from the spindle 27 during the flow. Heat generation is absorbed by the cooling air.

  Since the machining center 1 of the present embodiment has the cooling mechanism for the spindle 27 as described above, it has the following operations. That is, in the cooling path 51, the interval between the cooling paths 51a to 51e formed adjacent to each other is gradually narrower in the cooling air flow direction. Long air flow distance (flow time). Therefore, as the cooling air moves in the cooling path 51, the cooling air gradually absorbs the heat generated from the spindle 27, while the cooling air flow distance (flow time) gradually increases. Is compensated by an increase in the flow distance (flow time).

  Furthermore, in the cooling path 51, the flow area in the cooling paths 51 a to 51 e for each round is gradually increased toward the flow direction of the cooling air, so that the cooling air is lower on the lower side than the upper side of the spindle 27. The flow area (contact area with heat generation of the spindle 27) is large. Therefore, as the cooling air moves in the cooling path 51, the cooling air gradually absorbs heat generated from the spindle 27, while the cooling air flow area (contact area) gradually increases. Is compensated by an increase in the flow area (contact area).

  As described above, according to the machining center 1 according to the first embodiment, the cooling air for cooling the spindle 27 flows into the cooling path 51, and the cooling path 51 extends along the axial direction of the spindle 27. It was formed in multiple spirals. In the cooling path 51, the interval between the cooling paths 51a to 51e adjacent to each other gradually decreases from the air inflow part 64 toward the air outflow part 65, and the flow path area in the cooling paths 51a to 51e gradually increases. It was formed to be large. Therefore, even if the temperature of the cooling air flowing in the cooling passage 51 gradually increases in the flow direction, the flow distance (flow time) and the flow area (contact area) of the cooling air move in the flow direction. Since it gradually increases, the entire spindle 27 can be cooled uniformly.

  The housing 25 has a substantially cylindrical shape that houses the spindle 27 therein, and a spindle cooling cylinder 60 in which multiple spiral groove portions 63 (groove portions 63a to 63e) are formed along the axial direction on the outer peripheral surface thereof. Was provided. The cooling path 51 (cooling paths 51 a to 51 e) was formed in the gap between the outer peripheral surface of the spindle cooling cylinder 60 and the inner peripheral surface of the housing 25. Therefore, if the spindle cooling cylinder 60 is provided inside the housing 25, the cooling path 51 for cooling the spindle 27 can be formed.

  Further, the machining center 1 performs workpiece machining by rotating the tool 6 by the spindle motor 8. In order to allow cooling air to flow from the rear end side of the spindle 27, the machining center 1 and the lower end of the spindle 27 are used. An air outflow hole 25 b for allowing cooling air to flow out from the side (front end side) was formed on the side surface of the housing 25. Therefore, cooling air for cooling the spindle 27 is appropriately introduced from the outside of the housing 25 from the upper end side (rear end side) of the spindle 27 and from the lower end side (front end side) of the spindle 27 to the outside of the housing 25. Can be drained properly.

  Next, the machining center 1 which is the 2nd Embodiment of this invention is demonstrated based on drawing. The machining center 1 according to this embodiment is basically the same as that of the first embodiment, but the structure of the spindle cooling cylinder 70 and the cooling air discharge site are different. The following description will focus on differences from the first embodiment.

  First, the spindle cooling cylinder 70 will be described. FIG. 8 is a front view of the spindle cooling cylinder 70. As shown in FIG. 8, the spindle cooling cylinder 70 has a cylindrical main body 71, a flange portion 72, and a groove portion 73, similarly to the spindle cooling cylinder 60 (FIG. 6). However, in this embodiment, the groove portion 73 is formed so as to communicate about six turns along the axial direction, and the groove portions for each turn are formed as groove portions 73a, 73b, 73c, 73d, 73e, 73f from the upper side in front view. And The upper end of the groove 63 (that is, the upper end of the groove 73a) is an air inflow portion 74 into which cooling air described later flows, and the lower end of the groove 73 (that is, the lower end of the groove 73f) corresponds to cooling air described later. It is the air outflow part 75 which flows out.

  Then, in the groove portion 73, as in the spindle cooling cylinder 60 (FIG. 6), the interval at which the adjacent groove portions 73 a to 73 f are formed gradually narrows from the air inflow portion 74 toward the air outflow portion 75. Is formed. Further, in the groove portion 73, the substantially semicircular groove-shaped cross-sectional area of the groove portions 73 a to 73 f for each turn is formed so as to gradually increase from the air inflow portion 74 toward the air outflow portion 75. Further, the cylindrical main body 71 is formed with an air outflow hole 76 which is a through hole formed vertically from the lower surface thereof and communicates with the air outflow portion 75.

  Next, the cooling structure of the spindle 27 using the spindle cooling cylinder 70 will be described. 9 and 10 are enlarged side cross-sectional views of the main shaft 9 as seen from the right direction for explaining the flow of cooling air in the second embodiment. 9 represents only the housing 25 as a cross-sectional view, FIG. 10 represents the housing 25 and the spindle cooling cylinder 70 as a cross-sectional view, and the flow of cooling air is represented by arrows. 9 and 10, for easy understanding, the upper end of the groove 73 (that is, the cooling path 52) formed in the spindle cooling cylinder 70 is positioned at the right end in front view, and the lower end is the left end in front view. What is located in FIG.

  As shown in FIGS. 9 and 10, when the spindle cooling cylinder 70 is closely fixed inside the housing 25, the opening of the groove 73 is closed by the inner peripheral surface of the housing 25. A sealed space having a spiral groove shape is formed in the gap with 25. The spiral groove-shaped sealed space functions as a cooling air flow path (cooling path 52). In the present embodiment, since the groove portion 73 is formed so as to communicate about six rounds (groove portions 73a to 73f), when the spindle cooling cylinder 70 is closely fixed inside the housing 25, the groove portions 73a to 73a. The sealed spaces formed at 73f function as cooling paths 52a to 52f, respectively.

  As in the first embodiment, in the cooling path 52, the interval at which the cooling paths 52a to 52f adjacent to each other are formed is from the upper end (that is, the air inflow portion 74) to the lower end (that is, the air outflow). It becomes gradually narrower toward the portion 75). Further, the flow passage areas in the cooling passages 52 a to 52 f for each turn gradually increase from the air inflow portion 74 toward the air outflow portion 75.

  In the present embodiment, the housing 25 is provided with only the air inflow hole 25a (the air outflow hole 25b is not provided). The air inflow portion 74 communicates with the air inflow hole 25a, while the air outflow portion 75 communicates with the air outflow hole 76 described above. The air outflow hole 76 communicates with one end of an air outlet passage 39 a that is a through hole formed in the upper surface of the lid 39, and the other end of the air outlet passage 39 a communicates with the inner peripheral surface of the lid 39. ing. That is, the air outflow portion 75 communicates with the gap between the outer peripheral surface on the front end side (lower end side) in the axial direction of the spindle 27 and the inner peripheral surface of the lid 39 through the air outflow hole 76 and the air outlet passage 39a. .

  With this structure, when the air supply unit 100 supplies cooling air from the outside of the housing 25 to the inside of the air inflow hole 25a, the cooling air flows from the air inflow unit 74 to the air outflow unit 75 in the cooling path 52, It is led out to the gap between the outer peripheral surface on the lower end side of the spindle 27 and the inner peripheral surface of the lid 39 through the air outlet hole 76 and the air outlet path 39a. The derived cooling air is discharged downward from the spindle 27 through the gap between the spindle 27 and the lid 39. That is, the cooling air flowing in the cooling path 52 flows from the upper side to the lower side so that the cooling air flows around the spindle 27 from the upper side to the lower side. Heat generation is absorbed by the cooling air.

  Since the machining center 1 of the present embodiment has the cooling mechanism for the spindle 27 as described above, it has the following operations. That is, as in the first embodiment, as the cooling air flows in the cooling passage 52, the cooling air gradually absorbs heat generated from the spindle 27, while the cooling air flow distance (flow time) gradually increases. The cooling air flow area (contact area) gradually increases.

  Further, the cooling air flowing in the cooling passage 52 is discharged from the gap between the outer peripheral surface on the lower end side of the spindle 27 and the inner peripheral surface of the lid 39 through the air outflow hole 76 and the air outlet passage 39a. That is, since the cooling air is discharged from the gap formed at the lower end of the spindle 27, the entry of dust and dirt into the gap between the spindle 27 and the lid 39 is prevented.

  As described above, according to the machining center 1 according to the second embodiment, the cooling path 52 formed in the gap between the spindle 27 and the spindle cooling cylinder 70 corresponds to the groove portion 73 formed in the spindle cooling cylinder 70. The number of turns, the formation width, the flow path area, and the like can be arbitrarily changed. As in the first embodiment, even if the temperature of the cooling air flowing in the cooling passage 52 gradually increases in the flow direction, the cooling air flow distance (flow time) and flow area ( The contact area is gradually increased in the flow direction, so that the entire spindle 27 can be uniformly cooled.

  Further, in the machining center 1, the lower end portion (front end portion) of the spindle 27 is rotatably supported on the inner peripheral surface of the lid 39, and the air outflow hole 76 and the air outlet passage 39 a are arranged at the lower end portion (front end portion) of the spindle 27. The cooling air is supplied to the gap between the outer peripheral surface of) and the inner peripheral surface of the lid 39. Therefore, since the cooling air that has flowed through the cooling path 52 can be discharged from the gap formed at the lower end portion (front end portion) of the spindle 27, foreign matter can be purged from the spindle 27 with air.

  Next, the machining center 1 which is the 3rd Embodiment of this invention is demonstrated based on drawing. The machining center 1 according to the present embodiment is basically the same as the first and second embodiments, but the structure of the spindle cooling cylinder 80 and the cooling air discharge site are different. The following description will focus on differences from the first and second embodiments.

  First, the spindle cooling cylinder 80 will be described. FIG. 11 is a front view of the spindle cooling cylinder 80. As shown in FIG. 8, the spindle cooling cylinder 80 has a cylindrical main body 81 and a flange portion 82, similarly to the spindle cooling cylinder 60 (FIG. 6). In the present embodiment, two first groove portions 83 and second groove portions 86 having a substantially semicircular cross-sectional shape formed in a multiple spiral shape along the axial direction are formed on the outer peripheral surface of the cylindrical main body 81. Is formed. The first groove 83 is formed so as to communicate about 5 turns along the axial direction, and the second groove 86 is formed so as to communicate about 4 turns along the axial direction. And on the outer peripheral surface of the cylindrical main body 81, each turn of the 1st groove part 83 and each turn of the 2nd groove part 86 are alternately formed in the up-down direction.

  In addition, let the groove part for every round in the 1st groove part 83 be 1st groove part 83a, 83b, 83c, 83d, 83e from the front view upper side. The upper end of the first groove 83 (that is, the upper end of the first groove 83a) is the first air inflow portion 84 into which the cooling air flows, and the lower end of the first groove 83 (that is, the lower end of the first groove 83e). ) Is the first air outflow portion 85 through which the cooling air flows out. On the other hand, the groove part for each round in the 2nd groove part 86 is made into 2nd groove part 86a, 86b, 86c, 86d from the front view lower side. The lower end of the second groove portion 86 (that is, the lower end of the second groove portion 86a) is the second air inflow portion 87 into which the cooling air flows, and the upper end of the second groove portion 86 (that is, the upper end of the second groove portion 86d). ) Is the second air outflow portion 88 through which the cooling air flows out.

  Then, in the first groove portion 83, first groove portions 83a to 83e adjacent to each other are formed from the first air inflow portion 84 toward the first air outflow portion 85 in the same manner as the spindle cooling cylinder 60 (FIG. 6). The interval between the first groove portions 83a to 83e for each turn is gradually increased, and the cross-sectional area of the substantially semicircular groove shape is gradually increased. Similarly, in the second groove portion 86, the intervals at which the second groove portions 86a to 86d adjacent to each other are formed from the second air inflow portion 87 to the second air outflow portion 88 are gradually narrowed. The cross-sectional area of the substantially semicircular groove shape in each of the second groove portions 86a to 86d is gradually increased. That is, the first groove portion 83 and the second groove portion 86 are alternately formed in the opposite direction without overlapping each other, the formation intervals are gradually reduced, and the respective cross-sectional areas are gradually increased. It is getting bigger. The cylindrical body 81 is formed with an air outflow hole 89 which is a through hole formed perpendicularly from the upper surface and communicates with the second air outflow portion 88.

  Next, the cooling structure of the spindle 27 using the spindle cooling cylinder 80 will be described. 12 and 13 are enlarged side sectional views of the main shaft 9 as viewed from the right direction for explaining the flow of cooling air in the third embodiment. 12 shows only the housing 25 as a cross-sectional view, FIG. 13 shows the housing 25 and the spindle cooling cylinder 80 as a cross-sectional view, and the flow of cooling air is indicated by arrows. 12 and 13, in order to facilitate understanding, the upper end of the first groove portion 83 (that is, the first cooling path 53) formed in the spindle cooling cylinder 80 is positioned at the right end in front view, and the lower end thereof. Is positioned at the left end of the front view, and the upper end of the second groove 86 (that is, the second cooling passage 54) is positioned at the left end of the front view, and the lower end thereof is positioned at the left end of the front view. .

  As shown in FIGS. 12 and 13, when the spindle cooling cylinder 80 is closely fixed inside the housing 25, the first groove 83 and the second groove 86 are closed by the inner peripheral surface of the housing 25. Therefore, two independent spiral groove-shaped sealed spaces are formed in the gap between the spindle cooling cylinder 80 and the housing 25. The two spiral groove-shaped sealed spaces function as cooling air flow paths (first cooling path 53 and second cooling path 54). In the present embodiment, since the first groove 83 is formed by communicating about five rounds (grooves 83a to 83e), when the spindle cooling cylinder 80 is closely fixed inside the housing 25, each first groove 83 is formed. The sealed spaces formed in the first groove portions 83a to 83e function as first cooling passages 53a to 53e, respectively. Further, since the second groove portion 86 is formed so as to communicate about four rounds (second groove portions 86 a to 86 d), when the spindle cooling cylinder 80 is closely fixed inside the housing 25, each second groove portion 86 a. To 86d function as sealed cooling spaces 54a to 54d, respectively.

  As described above, the first cooling path 53 and the second cooling path 54 are formed in a multiple spiral shape along the axial direction of the spindle 27, and the first cooling path 53 and the second cooling path 54 do not overlap each other. In this way, they are alternately formed at intervals. That is, on the outer peripheral surface of the housing 25, the first cooling passages 53a to 53e are sequentially formed from the rear end side (upper end side) in the axial direction toward the front end side (lower end side) in the axial direction, and the first cooling paths 53a to 53e are formed in the opposite direction. Two cooling paths 54a to 54d are formed in order, and the first cooling paths 53a to 53e and the second cooling paths 54a to 54d are formed in parallel at intervals. Therefore, the first cooling passage 53 and the second cooling passage 54 formed on the outer peripheral surface of the housing 25 form independent cooling air passages without contacting (crossing) each other.

  As in the first embodiment, in the first cooling passage 53, the first cooling passages 53 a to 53 e that are adjacent to each other are gradually formed from the first air inflow portion 84 toward the first air outflow portion 85. The flow passage area in the first cooling passages 53a to 53e for each turn is gradually increased. Further, in the second cooling path 54, the formation intervals of the second cooling paths 54a to 54d adjacent to each other are gradually narrowed from the second air inflow portion 87 to the second air outflow portion 88. The flow passage areas in the two cooling passages 54a to 54d are gradually increased.

  In the present embodiment, in addition to the air inflow hole 25a and the air outflow hole 25b, the side surface of the housing 25 is formed perpendicular to the axial direction front end side (lower end side) from the outer peripheral direction to the axis line. An air inflow hole 25c which is a through hole is provided. An air supply portion 110 is provided at a portion where the air inflow hole 25c is formed on the outer peripheral surface of the housing 25, similarly to the air supply portion 100 provided in the air inflow hole 25a. The first air inflow portion 84 communicates with the air inflow hole 25a, while the first air outflow portion 85 communicates with the air outflow hole 25b. The second air inflow portion 87 communicates with the air inflow hole 25c, while the second air outflow portion 88 communicates with the air outflow hole 89 described above. The air outflow hole 89 communicates with a gap between the rear end surface (upper surface) in the axial direction of the spindle cooling cylinder 80 and the inner peripheral surface of the housing 25.

  With this structure, when the air supply unit 100 supplies cooling air from the outside of the housing 25 to the inside of the air inflow hole 25a, the cooling air is supplied from the first air inflow unit 84 to the first air outflow unit in the first cooling path 53. It flows to 85 and is discharged to the outside of the housing 25 from the air outflow hole 25b. That is, the cooling air flowing in the first cooling path 53 flows from the upper side to the lower side in the first cooling path 53a to 53e so as to turn around the outer periphery of the spindle 27. The heat generated from 27 is absorbed by the cooling air.

  Further, when the air supply unit 110 supplies cooling air from the outside of the housing 25 to the inside of the air inflow hole 25 c, the cooling air flows from the second air inflow portion 87 to the second air outflow portion 88 in the second cooling path 54. It flows to the gap between the upper surface of the spindle 27 and the inner peripheral surface of the housing 25 through the air outflow hole 89. The derived cooling air is discharged upward from the gap between the spindle 27 and the housing 25. That is, the cooling air flowing in the second cooling path 54 flows from the lower cooling path 54a to 54d from the lower side to the upper side so as to turn on the outer periphery around the spindle 27. The heat generated from 27 is absorbed by the cooling air.

  Since the machining center 1 of the present embodiment has the cooling mechanism for the spindle 27 as described above, it has the following operations. That is, along the axial direction of the spindle 27, the first cooling passage 53 and the second cooling passage 54, which are two multi-spiral air passages, are formed at intervals so as not to overlap each other. The cooling air flows from the first air inflow portion 84 toward the first air outflow portion 85 in the first cooling passage 53, and from the second air inflow portion 87 to the second air outflow portion 88 in the second cooling passage 54. The cooling medium flows toward it. Therefore, the cooling air flows spirally from both sides of the spindle 27 in the axial direction (that is, in the vertical direction) toward the opposing direction of the outer periphery thereof.

  Further, as in the first embodiment, as the cooling air flows in the first cooling path 53 and the second cooling path 54, the cooling air gradually absorbs heat generated from the spindle 27, while the cooling air The flow distance (flow time) is gradually increased and the flow area (contact area) of the cooling air is gradually increased.

  The cooling air flowing in the second cooling path 54 is discharged from the gap between the upper surface of the spindle 27 and the inner peripheral surface of the housing 25 through the air outflow hole 89. That is, since the cooling air is discharged from the gap formed at the upper end portion of the spindle 27, entry of dust, dust and the like into the gap between the spindle 27 and the housing 25 is prevented, and is discharged from the rear end portion of the spindle 27. The cooled air is led out from the opening 25d of the housing 25 to the outside.

  As described above, according to the machining center 1 according to the third embodiment, the cooling air for cooling the spindle 27 is caused to flow into the first cooling path 53 and the second cooling path 54. In 53, the cooling air flows from the rear end side of the spindle 27 toward the front end side, and in the second cooling path 54, the cooling medium flows from the front end side of the spindle 27 toward the rear end side. Further, the first cooling path 53 and the second cooling path 54 are formed in a multiple spiral shape along the axial direction of the spindle 27, and are formed at intervals so as not to overlap each other. Therefore, even if the temperature of the cooling air flowing in the first cooling path 53 and the second cooling path 54 gradually rises in the flow direction, the first flow direction formed in the entire circumference of the spindle 27 is different. Since the cooling air flows in the opposing direction in the cooling path 53 and the second cooling path 54, the entire spindle 27 can be uniformly cooled.

  A plurality of cooling paths (first cooling path 53 and second cooling path 54) formed in the gap between the spindle 27 and the spindle cooling cylinder 80 are the first groove 83 and the second groove formed in the spindle cooling cylinder 80. Depending on the groove portion 86, the number of turns, the formation width, the flow path area, and the like can be arbitrarily changed, and the formation number (here, two) can be arbitrarily changed. As in the first and second embodiments, even if the temperature of the cooling air flowing in the first cooling path 53 and the second cooling path 54 gradually increases in the flow direction, the cooling air Since the flow distance (flow time) and the flow area (contact area) gradually increase in the flow direction, the entire spindle 27 can be cooled uniformly.

  In the machining center 1, the upper end (rear end) of the spindle 27 is attached to the inner peripheral surface of the housing 25, and the air outflow hole 89 is formed between the upper surface (rear end surface) of the spindle 27 and the inner peripheral surface of the housing 25. Supply cooling air to the gap. Therefore, since the cooling air that has flowed through the second cooling path 54 can be discharged from the gap formed at the upper end (rear end) of the spindle 27, foreign matter can be purged of air from the main shaft 9.

  In the first to third embodiments, the machining center 1 corresponds to the “spindle cooling device for a machine tool” according to the present invention, and the cooling air corresponds to the “cooling medium” according to the present invention. The spindle cooling cylinders 60, 70, 80 correspond to the “spindle cooling member” of the present invention. The air supply units 100 and 110 correspond to the “cooling medium supply unit” of the present invention. The air inflow holes 25a and 25c correspond to the “cooling medium inflow portion” of the present invention, and the air outflow holes 25b, the air outflow hole 76, and the air outlet passage 39a correspond to the “cooling medium outflow portion” of the present invention.

  In addition, this invention is not limited to the said embodiment, Of course, various improvement and deformation | transformation are possible within the range which does not deviate from the summary of this invention. FIG. 14 is a front view of a modified example of the spindle cooling cylinder 60. FIG. 15 is an enlarged side cross-sectional view around the holder mounting hole 29 of the main shaft 9 provided with the annular holder 90.

  For example, as shown in FIG. 14, a packing member (packing 69) that is a rubber packing may be provided along the edge of the groove 63 on the outer peripheral surface of the cylindrical main body 61 of the spindle cooling cylinder 60. When the spindle cooling cylinder 60 is attached to the inside of the housing 25, the outer peripheral surface of the spindle cooling cylinder 60 and the inner peripheral surface of the housing 25 are more closely fixed by the packing 69, so that the cooling air flowing through the cooling path 51 is Thus, leakage into the gap between the spindle cooling cylinder 60 and the housing 25 is prevented. Therefore, leakage of the cooling air flowing through the cooling path 51 can be reliably prevented, and the cooling effect of the spindle 27 by the cooling air can be improved. It should be noted that a similar “packing member” can be provided for the spindle cooling cylinders 70, 80.

  As shown in FIG. 15, an annular holder 90 may be provided at the lower end of the lid 39 at the front end (lower end) in the axial direction of the main shaft 9. The annular holder 90 has a substantially ring shape in plan view, and is formed with a plurality of integral nozzles 91 and nozzle holes 92. When the tool 6 attached to the main shaft 9 is replaced, the coolant liquid supplied from the coolant hose (not shown) to each integrated nozzle 91 is sprayed from each nozzle hole 92 directly below the holder mounting hole 29, The tool holder 13 (tool 6) is cleaned. The control device (not shown) in the control panel 19 is only for at least one of a predetermined time during the operation of the machining center 1 and after the operation stop and a predetermined time during the injection of the coolant in the annular holder 90 and after the injection stop. In addition, the air supply unit 100 may be controlled to supply cooling air. Thereby, the supply timing of the cooling air can be appropriately adjusted in response to the operation of the machining center 1 and the cleaning operation of the tool 6 where the spindle 27 easily generates heat.

  The cooling air supply control by the control device (not shown) is not limited to the above, and various methods can be applied. For example, a control device (not shown) in the control panel 19 controls at least one of the supply amount and supply pressure of the cooling air supplied by the air supply unit 100 based on the amount of current supplied to the spindle motor 8. You may do it. Further, a control device (not shown) in the control panel 19 may control at least one of the supply amount and supply pressure of the cooling air supplied by the air supply unit 100 based on the temperature of the spindle 27. . Thereby, the supply amount and supply pressure of the cooling air can be appropriately adjusted based on the driving of the spindle motor 8 and the temperature of the spindle 27. It is to be noted that the cooling air supply control can be executed similarly for the air supply unit 110.

Further, the machining centers 1 according to the first to third embodiments may be arbitrarily combined or mounted. For example, in the machining center 1 according to the third embodiment,
The cooling air flowing out from the first air outflow portion 85 may be discharged from the front end side (lower end side) of the spindle 27 as in the second embodiment, or outflowing from the second air outflow portion 88. The cooling air may be discharged to the outside from the side surface of the housing 25 as in the first embodiment.

  Further, as exemplified in the third embodiment, when a plurality of cooling paths are provided in the machining center 1, the number, the forming direction, and the shape of the cooling paths can be arbitrarily set. For example, by forming grooves corresponding to the respective cooling paths in the spindle cooling cylinder 80 in advance, three or more cooling paths may be provided in the machining center 1, and the shape of each cooling path becomes a wave shape or a linear shape. You may do it.

  In the above embodiment, compressed air (cooling air) is exemplified as the “cooling medium”, but various media can be used as long as the spindle 27 can be effectively cooled. For example, as the “cooling medium”, another gas such as nitrogen or helium may be used, or a liquid such as water or oil may be used.

  The spindle cooling device for a machine tool of the present invention can be applied to a machine tool that cools a spindle with a cooling medium.

1 is a front view of a machining center 1. FIG. 1 is an overall perspective view of a machining center 1 excluding a splash cover 3. FIG. 2 is a front view of the machining center 1 centering on a tool change mechanism 20 and a spindle head 7. FIG. FIG. 3 is an enlarged side cross-sectional view of the spindle head 7 as viewed from the right direction. FIG. 3 is an enlarged side cross-sectional view of the main shaft 9 as viewed from the right direction. 3 is a front view of a spindle cooling cylinder 60. FIG. It is the side surface sectional enlarged view which looked at the main axis | shaft 9 from the right direction for demonstrating the flow of the cooling air in 1st Embodiment. 3 is a front view of a spindle cooling cylinder 70. FIG. It is the side surface sectional enlarged view which looked at the main axis | shaft 9 from the right direction for demonstrating the flow of the cooling air in 2nd Embodiment. It is the side surface sectional enlarged view which looked at the main axis | shaft 9 from the right direction for demonstrating the flow of the cooling air in 2nd Embodiment. 3 is a front view of a spindle cooling cylinder 80. FIG. It is the side surface sectional enlarged view which looked at the main axis | shaft 9 from the right direction for demonstrating the flow of the cooling air in 3rd Embodiment. It is the side surface sectional enlarged view which looked at the main axis | shaft 9 from the right direction for demonstrating the flow of the cooling air in 3rd Embodiment. It is a front view of the modification of the spindle cooling cylinder 60. FIG. It is a side cross-sectional enlarged view centering on a holder mounting hole 29 of a main shaft 9 provided with an annular holder 90.

Explanation of symbols

1 Machining Center 7 Spindle Head 8 Spindle Motor 9 Spindle 19 Control Panel 25 Housing 25a Air Inflow Hole 25b Air Outflow Hole 25c Air Inflow Hole 25d Opening 27 Spindle 39 Lid 39a Air Derivation Path 51a, 51b, 51c, 51d, 51e Cooling Path 52a, 52b, 52c, 52d, 52e, 52f Cooling path 53a, 53b, 53c, 53d, 53e First cooling path 54a, 54b, 54c, 54d Second cooling path 60 Spindle cooling cylinders 63a, 63b, 63c, 63d, 63e Groove part 64 Air inflow part 65 Air outflow part 69 Packing 70 Spindle cooling cylinders 73a, 73b, 73c, 73d, 73e, 73f Groove part 73a Groove part 74 Air inflow part 75 Air outflow part 76 Air outflow hole 80 Spindle cooling cylinders 83a, 83b, 83c , 83d 83e 1st groove part 84 1st air inflow part 85 1st air outflow part 86a, 86b, 86c, 83d 2nd groove part 87 2nd air inflow part 88 2nd air outflow part 89 Air outflow hole 90 Annular holder 100,110 Air supply Part

Claims (10)

A spindle rotatably supported through a bearing inside the housing, cooling medium supply means for supplying a cooling medium for cooling the spindle, and a flow path for the cooling medium provided in the outer peripheral direction of the spindle A plurality of cooling paths, a plurality of cooling medium inflow portions for allowing the cooling medium to flow into one end of the plurality of cooling paths from the outside of the housing, and the housing from the other end of the plurality of cooling paths. A spindle cooling device for a machine tool, comprising a plurality of cooling medium outflow portions for flowing out the cooling medium to the outside,
At least one of the plurality of cooling paths is a flow path through which the cooling medium flows from one end side to the other end side of the spindle,
The remainder of the plurality of cooling paths is a flow path through which the cooling medium flows from the other end side of the spindle toward the one end side.   The plurality of cooling paths are formed in a multi-spiral shape along the axial direction of the spindle, and the cooling paths are formed at intervals so as not to overlap each other. Cooling system.   At least one of the plurality of cooling paths is formed such that the flow path area gradually increases from the cooling medium inflow part of the cooling path toward the cooling medium outflow part of the cooling path. The spindle cooling device for a machine tool according to claim 1 or 2, wherein A spindle cooling member that houses the spindle inside is provided in the housing.
On the outer surface of the spindle cooling member, a plurality of multiple spiral grooves are formed along the axial direction thereof.
The spindle cooling device for a machine tool according to any one of claims 1 to 3, wherein the plurality of cooling paths are formed in a gap between the spindle cooling member and the housing.   In the gap between the spindle cooling member and the housing, a plurality of packing members for preventing leakage of the cooling medium flowing in the plurality of cooling paths are provided along the plurality of cooling paths, respectively. The spindle cooling device for a machine tool according to claim 4. In the machine tool, a tool is attached to and detached from one end portion of the spindle, and a motor is connected to the other end portion of the spindle, and the tool fitted on the spindle is rotated by the motor to perform workpiece machining. To do,
The plurality of cooling medium inflow portions are flow paths of the cooling medium for allowing the cooling medium to flow from one end side or the other end side of the spindle,
The plurality of cooling medium outflow portions are flow paths of the cooling medium for allowing the cooling medium to flow out from the other end side or one end side of the spindle, respectively. The spindle cooling device for the machine tool described. One end of the spindle is rotatably supported on the inner peripheral surface of a ring-shaped lid that prevents intrusion of foreign matter,
At least one of the plurality of cooling medium outflow portions supplies the cooling medium to a gap between an outer peripheral surface of one end of the spindle and an inner peripheral surface of the lid, and a gap formed at one end of the spindle The spindle cooling device for a machine tool according to claim 6, wherein the cooling medium is discharged via a head.   The machine tool according to claim 6 or 7, wherein the cooling medium supply means controls at least one of a supply amount and a supply pressure of the cooling medium based on an amount of current supplied to the motor. Spindle cooling device. A tool cleaning means for cleaning the tool by spraying a coolant liquid onto the tool attached to and detached from the spindle;
The cooling medium supply means supplies the cooling medium only to at least one of a predetermined time during operation of the machine tool and after operation stop and a predetermined time after injection of the coolant liquid by the tool cleaning means and after injection stop. The spindle cooling device for a machine tool according to any one of claims 6 to 8, wherein the spindle cooling device is supplied. 10. The machine tool according to claim 6, wherein the cooling medium supply means controls at least one of a supply amount and a supply pressure of the cooling medium based on a temperature of the spindle. Spindle cooling device.

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