JPH0588851U - Spindle device with built-in motor - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a spindle device with a built-in motor capable of efficiently and effectively cooling the rotor and the like of a spindle motor while ensuring the rigidity of the spindle shaft. A coil spring 21 for urging a drawbar 16 for locking a tool holder 2 inserted into a spindle shaft 1 is arranged inside a rotor 10 of a spindle motor 8, and a fluid passage 21a is formed by the coil spring 21. To form. A machining fluid supply passage 43 for supplying the machining fluid of the tool holder 2 is formed from the rear portion to the tip portion of the spindle shaft 1, and the fluid passage 21a is used as a part of the machining fluid supply passage 43. A cooled machining fluid is used as the machining fluid supplied to the machining fluid supply path 43.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a spindle device for a machine tool, and more particularly to a motor-incorporated spindle device having a cooling structure for a spindle motor.

[0002]

[Prior Art]

 Conventionally, as a spindle device for a machine tool, for example, one disclosed in Japanese Utility Model Laid-Open No. 60-194452 is known.

In this spindle device, a tapered hole is formed at the tip of a spindle shaft rotatably supported by a housing via a bearing, and the rear part of the tool holder is inserted into this tapered hole by taper fitting. It was done like this. Then, the spindle shaft is rotationally driven via a gear inserted in the middle portion of the spindle shaft.

Further, this spindle device is provided with a rod-shaped drawer which is slidably inserted from a rear end portion thereof toward the taper hole in a through hole formed in an axial center portion of the spindle shaft. , The drawbar locks the tool holder in a disengageable manner.

More specifically, the tool holder is provided with a pull stud at the rear end thereof, and the pull stud is concentric with the through hole from the tapered hole of the spindle shaft when the tool holder is attached to the spindle shaft. It is designed to be inserted into.

On the other hand, the draw bar is provided with a fitting insertion hole into which the pull stud can be removably fitted and inserted only when it is advanced toward the taper hole to a predetermined advance position. When the drawbar is retracted to a predetermined retracted position while the pull stud is inserted, the pull stud is locked irremovably through a plurality of balls attached to the peripheral wall of the insert hole. Is configured. The drawbar is inserted into the through hole and is biased to the retracted position by a coil spring externally inserted in the drawbar, and is slid forward and backward by a cylinder connected to the rear end of the drawbar. It is designed to be driven and driven.

Therefore, in such a spindle device, when inserting the tool holder onto the spindle shaft, first, with the draw bar advanced to the above-mentioned advance position by the cylinder, the rear part of the tool holder is placed in the tapered hole of the spindle shaft. The pull stud of the tool holder is inserted into the insert hole of the draw bar while being inserted. Then, the draw bar is retracted to the retracted position by the biasing force of the coil spring together with the operation of the cylinder, whereby the tool holder is firmly taper-fitted to the spindle shaft and the draw bar is pulled through the pull stud. Be locked.

In this spindle device, a plurality of machining liquid supply passages are formed inside the spindle shaft from the rear end portion to the front end portion, and cutting oil is supplied to the tool holder via the machining liquid supply passages. I am trying to supply. In this case, the machining fluid is introduced from the outside into the machining fluid supply path through a rotary joint connected to the rear end of the machining fluid supply path. Inside the hole, it communicates with the machining fluid passage formed inside the tool holder.

On the other hand, in this type of spindle device, in recent years, a spindle device with a built-in motor has been put into practical use in which a housing for supporting the spindle shaft is internally provided with a spindle motor for rotationally driving the spindle shaft. Is becoming more common.

This motor-incorporated spindle device is one in which the rotor of the spindle motor is integrally provided on the spindle shaft, and by adopting such a configuration, a gear or the like for driving the spindle shaft is unnecessary. Therefore, the structure of the drive mechanism can be simplified.

Also in this type of motor-incorporated spindle device, normally, as described above, a drawbar mechanism for locking the tool holder inserted into the spindle shaft and the working liquid are supplied to the tool holder. A machining liquid supply path and the like are provided inside the spindle shaft.

By the way, in the spindle device with a built-in motor of this kind, the heat of the spindle motor is directly transmitted from the rotor to the spindle shaft, so that the spindle shaft is apt to have a relatively high temperature. When the spindle shaft becomes hot in this way, due to thermal expansion and the like, an excessive preload is applied to the bearing that rotatably supports the spindle shaft in the housing, and the durability and operability of the bearing are increased. There is a risk that it will be significantly impaired.

Therefore, in this type of motor-incorporated spider device, a cooling structure for cooling the rotor of the spindle motor or the spindle shaft is usually provided. The one disclosed in Japanese Patent Laid-Open No. 142142 is known. This cooling structure forms a plurality of air passages extending in the axial direction inside the spindle motor inside the spindle motor, and supplies air to the air passages to cool the rotor of the spindle motor. It was done.

However, such a cooling structure has the following disadvantages.

That is, as described above, the drawbar mechanism is usually provided inside the spindle shaft, and the working liquid supply passage is also provided. Therefore, as described above, if a plurality of cooling passages such as air passages are further formed inside the spindle shaft, the rigidity of the spindle shaft is significantly reduced. If the diameter of the spindle shaft is increased in order to secure the rigidity of the spindle shaft, the spindle device becomes larger, and if the number of cooling passages is reduced, a sufficient cooling effect cannot be obtained. ..

Further, in particular, in the one disclosed in Japanese Patent Application Laid-Open No. 3-142142, air for cooling the rotor of the spindle motor is supplied from the space inside the housing that houses the rotor and the stator of the spindle motor. Since the air is supplied to the air passage in the spindle shaft, air heated to some extent by the heat generated by the stator is supplied to the air passage, making it difficult to efficiently cool the rotor and spindle shaft. ..

[0017]

[Problems to be solved by the device]

 It is an object of the present invention to eliminate such inconvenience and to provide a motor-incorporated spindle device capable of efficiently and effectively cooling the rotor and the like of the spindle motor while ensuring the rigidity of the spindle shaft.

[0018]

[Means for Solving the Problems]

 In order to achieve such an object, the present invention provides a spindle shaft having a tapered hole at a tip end thereof for inserting and removing a tool holder by taper fitting, and a spindle shaft enclosing an outer peripheral portion of the spindle shaft. A housing for rotatably supporting the spindle, and a spindle motor having a rotor mounted inside the housing to rotate the spindle shaft and integrally rotatably mounted on an outer peripheral surface of an intermediate portion of the spindle shaft. A through hole concentrically extending from the rear end of the spindle shaft toward the taper hole; and a through hole slidably inserted from the rear end of the spindle shaft toward the taper hole. The tool holder can be freely inserted into and removed from the taper hole at the sliding position, and the tool holder inserted into the taper hole at the other predetermined sliding position is irremovably locked. A rod-shaped drawbar having a locking portion at its tip, a coil spring that is inserted into the through hole and externally inserted into the drawbar, and biases the drawbar to the locking position of the tool holder, and the taper. A spindle device provided with a machining fluid supply path formed through the inside of the spindle shaft from a rear portion to a tip portion of the spindle shaft in order to supply the machining fluid to the tool holder inserted in the hole, The coil spring is provided inside the rotor of the spindle motor so as to extend in the axial direction thereof, and has a spiral fluid between the inner peripheral surface of the through hole of the spindle shaft and the outer peripheral surface of the drawbar. A cooling fluid is used as the machining fluid, and the machining fluid supply channel is formed with the spiral fluid passage in the middle thereof. .

The spindle shaft has a spiral groove formed on the outer peripheral surface supported by the housing, and a cylindrical body that covers the spiral groove and is fixed to the outer peripheral surface of the spindle shaft is provided. It is characterized in that it is rotatably supported by a bearing provided inside the housing via the above, and the machining liquid supply path is formed with the spiral groove in the middle thereof.

Further, a cooling jacket, which encloses the stator of the spindle motor fixed to the inner peripheral surface of the housing and is formed in a spiral shape in the housing, and supplies / discharges a cooling liquid to / from the cooling jacket. In order to do so, a cooling liquid supply passage and a cooling liquid discharge passage that are in communication with and connected to the cooling jacket are provided.

[0021]

[Action]

 According to the present invention, when performing a machining operation, the tool holder is inserted into the taper hole of the spindle shaft and taper-fitted like the conventional spindle device. By sliding the tool holder to the locking position, the tool holder is locked via the locking portion of the draw bar.

During machining, the cooled machining fluid is introduced from the rear portion of the spindle shaft into the machining fluid supply passage, and further passes through the machining fluid supply passage to be attached to the tip portion of the spindle shaft. And is supplied to the tool holder. At this time, the working fluid flowing in the working fluid supply passage is in the spiral fluid passage formed by the coil spring for urging the draw bar to the locking position inside the rotor of the spindle motor. Through a spiral flow, which cools the rotor. The machining fluid also cools the spindle shaft itself while passing through the machining fluid supply passage.

Further, when the spiral groove is provided in the middle of the machining liquid supply path, the bearing that pivotally supports the spindle shaft is made of the cooled machining liquid that flows in the spiral groove, and Cooled through the body. Therefore, the bearing is efficiently cooled in the vicinity thereof.

When the spiral cooling jacket is formed on the housing, the cooling liquid introduced into the cooling jacket from the cooling liquid supply passage spirals around the stator of the spindle motor in the cooling jacket. And the stator of the spindle motor is efficiently cooled.

[0025]

【Example】

 An example of the motorized spindle device of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory side view showing the housing of the spindle device in a broken manner, FIGS. 2 and 3 are longitudinal sectional views of a front portion and a rear portion of the spindle device, and FIG. 4 is a view showing the housing of the spindle device. FIG. 5 is an explanatory side view showing a broken view at a position different from FIG. 1, and FIG. 5 is a partially enlarged view showing an enlarged main part of FIG.

In FIG. 1, 1 is a spindle shaft, 2 is a tool holder inserted in the tip of the spindle shaft 1, and 3 is a housing that encloses the outer peripheral portion of the spindle shaft 1 over substantially its entire length.

The spindle shaft 1 is provided with a plurality of bearings 5 whose front portion is concentric with the spindle shaft 1 between the front spindle portion 4 of the housing 3 and the spindle shaft 1 and is axially spaced. (Hereinafter referred to as front bearing 5) is rotatably supported by the support shaft portion 4, and its rear portion is concentric with the spindle shaft 1 between the rear support shaft portion 6 of the housing 3 and the support shaft portion 6. It is rotatably supported on the support shaft portion 6 via an interposed bearing 7 (hereinafter, referred to as a rear bearing 7).

In this case, the front part of the spindle shaft 1 is supported by the front bearings 5 via the cylindrical bodies 49 inserted therein as described later, and the rear part of the spindle shaft 1 is The outer peripheral surface is directly supported by the rear bearing 6.

A spindle motor 8 for rotationally driving the spindle shaft 1 is installed inside the housing 3 corresponding to the intermediate portion of the spindle shaft 1. The spindle motor 8 includes a rotor 9 integrally rotatably attached to an outer peripheral surface of an intermediate portion of the spindle shaft 1, and a rotor 9 that covers the rotor 9 and is fixed to an inner peripheral surface of the housing 3. A stator 10 and a coil 11 wound around the stator 10 are provided, and the coil 11 is energized to rotate and drive the spindle shaft 1 together with the rotor 9 as in a normal motor.

As shown in FIGS. 2 and 3, a through hole 12 is formed in the axial center of the spindle shaft 1, and the tip of the through hole 12 extends from the inside to the tip. A taper hole 13 having a diameter is formed. The tool holder 2 has a tapered portion 14 having a shape corresponding to the tapered hole 13 at the rear portion thereof. By inserting the tapered portion 14 into the tapered hole 13 and taper-fitting the both, the spindle shaft 1 Is concentrically attached to the tip of the. At this time, the tool holder 2 has a drawbar 16 provided inside the spindle shaft 1 with a pull stud 15 concentrically projecting from the rear end of the tapered portion 14 to the inside of the through hole 12 as described below. The spindle shaft 1 is fixed to the spindle shaft 1 by this, and is rotatable together with the spindle shaft 1.

The draw bar 16 is a rod-shaped member slidably inserted into the through hole 12 of the spindle shaft 1 from its rear end toward the pull stud 15 of the tool holder 2, and has a tool holder at its tip. A fitting insertion hole 17 into which the tip portion of the pull stud 15 can be fitted and inserted at the time of insertion of the second member 2 is formed. Further, a plurality of holes 18 are bored in the radial direction from the inner peripheral surface to the outer peripheral surface of the draw bar 16 at a position near the opening end of the fitting hole 17, and a spherical body 19 is fitted into each of these holes 18. There is. Each spherical body 19 is capable of projecting and retracting on the inner surface side or outer surface side of the fitting hole 17.

In this case, the draw bar 16 is slidable between the position shown by the solid line (retracted position) and the position shown by the phantom line (advanced position) in FIG. The outer peripheral surface of the tip end portion of the draw bar 16 is slidably contacted with the inner wall of the through hole 12 over almost the entire surface thereof so that the projecting portion protrudes toward the inside of the fitting insertion hole 17. In this state, the tip of the pull stud 15 fitted into the fitting hole 17 cannot be removed by the sphere 19. An annular groove 20 is formed on the inner peripheral surface of the through hole 12 facing the hole 18 at the advance position of the draw bar 16, and at this advance position, each sphere 19 is located inside the fitting insertion hole 17. It is buried in each hole 18 and can project into the annular groove 20. In this state, the pull stud 15 of the tool holder 2 is inserted into and removed from the fitting insertion hole 17.

Therefore, the tool holder 2 is inserted into the spindle shaft 1 by inserting the taper portion 14 of the tool holder 2 into the taper hole 13 of the spindle shaft 1 while the drawbar 16 is moved to the forward position. The pull stud 15 of the tool holder 2 is fitted into the fitting hole 17 of the drawbar 16, and then the pull stud 15 of the tool holder 2 is moved to the retracted position. 15 is locked in the fitting hole 17 of the drawbar 16 via the sphere 19 so as not to be pulled out.

As shown in FIGS. 2 and 3, inside the through hole 12 of the spindle shaft 1, inside the rotor 9 of the spindle motor 8, the coil spring 21 externally fitted to the draw bar 16 is housed. Has been done. This coil spring 21 is compressed between a jaw portion 22 provided on the inner wall of the front portion of the through hole 12 and a jaw portion 23 provided on the outer peripheral surface of the rear portion of the drawbar 16 to move the drawbar 16 to the retracted position side. Is urged to. The coil spring 21 is formed to have a rectangular cross section, and forms a fluid passage 21a spirally extending inside the rotor 9 between the inner peripheral surface of the through hole 12 and the outer peripheral surface of the drawbar 16. ..

As shown in FIGS. 3 and 5, the drawbar drive mechanism 24 that drives the drawbar 16 as described above is provided at the rear portion of the housing 3.

The drawbar driving mechanism 24 is integrally formed on a cylindrical body 25 inserted into the through hole 12 in the rear portion of the spindle shaft 1 toward the drawbar 16 and an outer peripheral surface of an intermediate portion of the cylindrical body 25. A piston 26 and a spool valve 27 slidably inserted in the rear portion of the tubular body 25 are provided.

As shown in FIG. 5, the tip of the tubular body 25 is concentrically screwed to the rear end of the drawbar 16, and is slidable in the through hole 12 of the spindle shaft 1 integrally with the drawbar 16. Has been done.

The piston 26 is slidably inserted in an annular groove 28 formed in the inner peripheral surface of the through hole 12 of the spindle shaft 1, and the flow defined by the piston 26 is formed in the annular groove 28. The body chambers 29 and 30 are formed.

The spool valve 27 is of a bottomed tubular shape having a bottom portion 27 a at its tip, and a large diameter portion 27 b formed from its rear end to an intermediate portion is slidably contacted with the inner peripheral surface of the tubular body 25. The tip end of the spool valve 27 is formed to have a small diameter with a gap from the inner peripheral surface of the tubular body 25. A spring 31 is externally inserted between the spool valve 27 and the inner peripheral surface of the tubular body 25 at the tip portion formed to have a small diameter, and the spring 31 is provided in front of the spool valve 27 on the inner peripheral surface of the tubular body 25. The spool valve 27 is urged rearward by being compressed between the annular jaw portion 32 formed on the above and the tip surface of the large diameter portion 27b of the spool valve 27.

In the normal state, the spool valve 27 is retracted by the biasing force of the spring 31 as shown by the solid line in FIG. 5, and the rear end of the spool valve 27 is fixed to the inner peripheral surface of the tubular body 25. Is abutted against and locked. When the spool valve 27 is moved to the front end side against the biasing force of the spring 31, the front end portion of the spool valve 27 comes into contact with the annular jaw portion 32 as shown by a phantom line in FIG. There is.

The fluid chamber 30 behind the piston 26 is communicated with the inside of the tubular body 25 through a plurality of communication holes 34 which are opened in the fluid chamber 30 and are bored in the tubular body 25 in the radial direction. It communicates with the inside of the spool valve 27 via a plurality of communication holes 35 formed in the peripheral wall portion of the tip end portion of 27 in the radial direction. In this case, the communication holes 34 and 35 are separated from each other in the axial direction of the tubular body 25 and the spool valve 27 when the spool valve 27 is retracted to the position where the spool valve 27 comes into contact with the snap ring 33 by the urging force of the spring 31. However, when the spool valves 27 are advanced to the position where they come into contact with the annular jaw portion 32, they face each other.

The inside of the tip end side of the cylindrical body 25 is connected to a machining liquid supply passage 43, which will be described later, which is formed inside the drawbar 16 or the like so as to supply the machining liquid to the tool holder 2 as described later. The inside of the rear end of the tubular body 25 (the inside of the spool valve 27) communicates with the machining fluid supply pipe 36 (see FIG. 3) provided outside the housing 3 via the rotary joint 37. It is connected.

The fluid chamber 29 in front of the piston 26 communicates with a fluid passage 38 formed inside the spindle shaft 1 from the location of the fluid chamber 29 to the rear end portion of the spindle shaft 1. 38 is connected to and connected to a fluid supply pipe 39 provided outside the housing 3 via a fluid passage 40 (shown in FIG. 3) formed at the rear end of the housing 3. The fluid chamber 29 is also communicated with the inside of the distal end portion of the tubular body 25 through a communication hole 41 that is opened in the fluid chamber 29 and is bored in the tubular body 25 in the radial direction.

An annular projection 42 is concentrically provided on the front end surface of the piston 26, and the piston 26 is moved forward so that the annular projection 42 abuts on the front wall of the annular groove 28. When this is done, the communication hole 41 is shielded from the fluid passage 38 by the annular projection 42.

In the drawbar drive mechanism 24, normally, the coil body 21 biases the drawbar 16 to the retracted position so that the cylindrical body 25 is retracted together with the drawbar 16 and the piston 26 of the cylindrical body 25 is retracted. It contacts the rear wall of the annular groove 28. Further, normally, the spool valve 27 is retracted by the biasing force of the spring 31 to a position where the rear end of the spool valve 27 contacts the snap ring 33. Then, in this state, the machining fluid supply pipe 36 is communicated with the machining fluid supply passage 43 through the rotary joint 37, the inside of the spool valve 27, the communication hole 35, and the inside of the tip end side of the tubular body 25. As a result, the working fluid can be supplied from the working fluid supply pipe 36 to the working fluid supply passage 43.

On the other hand, in the drawbar drive mechanism 24, when the relatively high pressure machining fluid is introduced from the machining fluid supply pipe 36 into the spool valve 27, the spool valve 27 moves forward against the urging force of the spring 31. As a result, the bottom portion 27a of the spool valve 27 abuts on the annular jaw portion 32 of the tubular body 25, whereby the interior of the spool valve 27 is shielded from the interior of the tubular body 25 on the tip end side. At this time, the working fluid flowing into the fluid chamber 30 through the communication hole 35 of the spool valve 27 and the communication hole 34 of the cylindrical body 25 resists the biasing force of the coil spring 21 due to the hydraulic pressure. The piston 26 is advanced together with the tubular body 25, whereby the draw bar 16 is slid to the advanced position.

As shown in FIGS. 2 and 3, a machining liquid supply passage 43 for supplying the machining liquid from the machining liquid supply pipe 36 to the tool holder 2 is formed inside the spindle shaft 1. ..

The machining fluid supply passage 43 communicates with the inside of the tip end side of the tubular body 25 of the drawbar drive mechanism 24, and the first machining fluid passage 44 formed inside the rear portion of the drawbar 16 and the first machining fluid passage 44. The fluid passage 21a formed by the coil spring 21 in communication with the machining fluid passage 44, and the second machining fluid passage 45 formed in the front portion of the drawbar 16 in communication with the fluid passage 21a. And a spiral groove 46 formed on the outer peripheral surface of the front part of the spindle shaft 1 so as to communicate with the second machining liquid passage 45.

In this case, as shown in FIGS. 1 and 2, the spiral groove 46 is formed on the outer peripheral surface supported by the front bearing 5 on the front side of the spindle shaft 1, on the inner ring of the rearmost front bearing 5. An annular groove 47 formed in the outer peripheral surface of the spindle shaft 1 at a position of its leading end and its rear end, which is formed in a spiral shape from a position facing to the inner ring of the frontmost front bearing 5. It is connected to 48. A cylindrical body 49 is attached to the outer peripheral portion of the front portion of the spindle shaft 1 so as to cover the spiral groove 46 and the annular grooves 47, 48, and the spindle body 1 of the spindle shaft 1 is inserted through the cylindrical body 49. The front part is pivotally supported by the inner ring of each front bearing 5. The cylindrical body 49 is fixed to the outer peripheral surface of the spindle shaft 1 by shrink fitting and is integrated with the spindle shaft 1.

As shown in FIG. 3, the first working fluid passage 44 is formed in the axial center portion of the drawbar 16 from the rear end portion thereof to the portion facing the rear end portion of the fluid passage 21a, and the tip end portion thereof is drawn. 16 is communicated with the rear end of the fluid passage 21a through a plurality of communication holes 50 bored in the radial direction.

As shown in FIG. 2, the second machining fluid passage 45 is located in the axial center of the drawbar 16 from a portion facing the tip of the fluid passage 21 a to a portion facing the rear end of the spiral groove 46. And a rear end thereof communicates with the tip of the fluid passage 21a through a plurality of communication holes 51 formed in the drawbar 16. The tip portion of the second machining fluid passage 45 is provided with a plurality of communication holes 52 bored in the radial direction from the tip portion to the outer peripheral surface of the drawbar 16 and the spindles in communication with the communication holes 52. A plurality of annular grooves 53 formed in the inner wall of the through hole 12 of the shaft 1 and a plurality of holes formed in the radial direction of the spindle shaft 1 are communicated with the annular groove 53 and the annular groove 48 of the spindle shaft 1. It is communicated with the rear end of the spiral groove 46 through the communication hole 54 in order. In this case, the annular groove 53 extends in the axial direction of the drawbar 16 so that it can communicate with the communication hole 52 even when the drawbar 16 is slid as described above.

A machining liquid supply passage 55 for supplying the machining fluid to the tool 2a held by the tool holder 2 is formed inside the tool holder 2, and the machining fluid supply passage 55 is It communicates with an annular groove 56, which is a machining liquid inlet formed on the outer peripheral surface of the tapered portion 14 of the tool holder 2 that is fitted into the tapered hole 13 of the pindle shaft 1. A communication hole 57 is formed at the tip of the spindle shaft 1 from the annular groove 47 to the inner wall of the taper hole 13 and obliquely forward. The communication hole 57 connects the tool holder 2 to the spindle. It is designed to communicate with the annular groove 56 of the tool holder 2 in a state of being attached to the shaft 1.

With this configuration, the machining fluid introduced from the machining fluid supply pipe 36 through the rotary joint 37 into the cylindrical body 25 of the drawbar drive mechanism 24 is in the state where the spool valve 27 is retracted as described above. Then, the fluid is supplied from the rear end portion of the draw bar 16 to the first machining fluid passage 44 of the machining fluid supply passage 43. Then, the machining fluid supplied to the first machining fluid passage 44 is supplied from the first machining fluid passage 44 to the communication hole 50, the spiral fluid passage 21a, the communication hole 51, the second machining fluid passage 45, It is supplied to the annular groove 56 of the tool holder 2 through the communicating hole 52, the annular groove 53, the communicating hole 54, the annular groove 48, the spiral groove 46, the annular groove 47 and the communicating hole 57 in order, and further from the annular groove 56 to the tool holder. It is supplied to the tool 2a via the two machining liquid supply passages 55.

As shown in FIG. 4, the housing 3 includes a cooling jacket 58 for cooling the stator 10 of the spindle motor 8, a cooling liquid supply passage 59 for supplying a cooling liquid to the cooling jacket 58, and a cooling liquid. A cooling liquid discharge path 60 for discharging the cooling liquid supplied to the jacket 58 is provided. In this case, the cooling jacket 58 surrounds the periphery of the stator 10 and is formed in a spiral shape on the side wall portion 61 in the middle portion of the housing 3.

The cooling liquid supply passage 59 is formed so as to communicate with the rear end of the cooling jacket 58 from the rear part of the housing 3 through the inside of the side wall part 61, and is provided outside at the rear end. The cooling liquid supply pipe 62 is connected and connected. The cooling liquid discharge passage 60 is formed through the inside of the side wall portion 61 from the tip of the cooling jacket 58 to the rear of the housing 3, and the cooling liquid discharge pipe 63 provided outside communicates with the rear end thereof. ·It is connected.

With such a configuration, the cooling liquid supplied from the cooling liquid supply pipe 62 to the cooling liquid supply passage 59 is introduced into the cooling jacket 58 from the cooling liquid supply passage 59, and then, at the rear end of the cooling jacket 58. After being spirally flowed around the stator 10 from the portion to the tip, it is discharged to the cooling liquid discharge pipe 63 through the cooling liquid discharge passage 60.

2 and 3, those denoted by reference numeral 64 are a plurality of injection nozzles attached to the front part of the housing 3 to inject and supply oil air to each front bearing 5, Those denoted by reference numerals 65, 66 and 67 are provided in the housing 3 so as to supply oil air from the outside to the injection nozzles 64, the spindle motor 8, the rear bearing 7 and the like, and further to discharge the supplied oil air to the outside. The oil and air passage.

Next, the operation of the spindle device will be described with reference to FIGS. 2 to 4.

In this spindle device, as described above, by supplying the relatively high-pressure working liquid from the working liquid supply pipe 36 into the cylindrical body 25 (the spool valve 27) of the drawbar drive mechanism 24, The drawbar drive mechanism 24 moves the drawbar 16 to the forward position. Then, in this state, as described above, the tool holder 2 is inserted into the tip end portion of the spindle shaft 1 by taper fitting.

Then, the supply of the machining fluid from the machining fluid supply pipe 36 into the spool valve 27 is released, whereby the spool valve 27 of the drawbar drive mechanism 24 is retracted by the urging force of the spring 31, as described above. The working fluid supply pipe 36 is communicated with the working fluid supply passage 43, and the drawbar 16 is retracted to the retracted position by the urging force of the coil spring 21, so that the pull stud 15 of the tool holder 2 is moved to the drawbar 16 as described above. Is locked at the tip of the. As a result, the tool holder 2 cannot be removed from the spindle shaft 1 and is rotatable together with the spindle shaft 1. During machining, the spindle motor 8 rotates the spindle shaft 1 together with the tool holder 2 in this state.

On the other hand, at the time of this machining, the machining fluid is supplied from the cooling fluid supply pipe 36 to the machining fluid supply path 43 through the rotary joint 37 and the inside of the cylindrical body 25 of the drawbar drive mechanism 24. Further, as described above, it is supplied to the tool 2a through the first machining fluid passage 44, the spiral fluid passage 21a, the first machining fluid passage 45, the spiral groove 46, and the machining fluid supply passage 55 of the tool holder 2 in this order. To be done.

At this time, the working fluid is cooled in advance. Therefore, when the working fluid spirally flows in the fluid passage 21a, the rotor 9 of the spindle motor 8 is cooled by the working fluid. Further, at this time, when the working fluid flows through the spiral groove 46, the front bearing 5 is cooled by the working fluid at a position close to the front bearing 5.

At this time, the cooling liquid is supplied from the cooling liquid supply pipe 62 to the cooling jacket 58 through the cooling liquid supply passage 59, and the cooling liquid is supplied to the stator 10 of the spindle motor 8 in the cooling jacket 58. The stator 10 is cooled by spirally flowing around the circumference.

At this time, the cooled oil air is supplied to and discharged from the front bearing 5, the rear bearing 7, and the spindle motor 8 through the injection nozzle 64 and the oil air passages 65 to 67. In addition, the front bearing 5, the rear bearing 7, and the spindle motor 8 are cooled, and the oil air is used as a lubricant for the front bearing 5, the rear bearing 7, and the spindle motor 8.

Therefore, in such a spindle device, the machining liquid supplied to the tool holder 2 through the inside of the spindle shaft 1 is used as the cooling liquid, the spindle shaft 1, the rotor 9 of the spindle motor 8, the front bearing 5 Is efficiently cooled.

In particular, the fluid passage 21 a for cooling the rotor 9 of the spindle motor 8, the cooling jacket for cooling the stator 10 of the spindle motor 8 and the spiral groove 46 for cooling the front bearing 5 are provided. By forming the spiral shape, the rotor 9, the stator 10 and the front bearing 5 are uniformly cooled, and these can be effectively cooled.

Further, the working fluid supply passage 43 is used as a cooling fluid passage for cooling the rotor 10 and the like, and the fluid passage 21a for cooling the rotor 9 is formed by the coil spring 21 related to the drawbar mechanism. Since the spiral groove 46 for cooling the front bearing 5 is formed on the outer peripheral surface of the spindle shaft 1, the volume of the fluid passage formed or formed in the spindle shaft 1 or the draw bar 16 inserted therein is small. As a matter of fact, it is possible to sufficiently secure these rigidity.

[0068]

[Effect of the device]

 As is apparent from the above description, according to the present invention, the coil spring for urging the draw bar to the locking position of the tool holder is arranged inside the rotor of the spindle motor integrally attached to the spindle shaft. A spiral fluid passage is formed by the coil spring, and the fluid passage is provided in the machining fluid supply passage as a part of the machining fluid supply passage for supplying the machining fluid to the tool holder. By using the cooling fluid, the number of fluid passages formed in the spindle shaft is reduced, and the rigidity of the spindle shaft is sufficiently ensured, while the rotor of the spindle shaft and spindle motor is made efficient. Cools well and effectively, which in turn reduces the load on the bearings that support the spindle shaft and improves its durability. It can be.

Then, the spindle shaft is supported by the bearing through a cylindrical body that covers the spiral groove formed on the outer peripheral surface of the spindle shaft and is fixed to the spindle shaft, and also serves as a part of the machining liquid supply path. By providing the spiral groove in the machining liquid supply path, the rigidity of the spindle shaft can be secured and the bearing can be efficiently cooled, and the durability of the bearing can be improved.

In addition, since the cooling jacket formed by enclosing the stator of the spindle motor in the housing is formed in a spiral shape, the stator can be efficiently and effectively cooled, and the rotor using the fluid passages can be cooled. It is possible to efficiently suppress the heat generation of the spindle motor together with the above cooling.

[Brief description of drawings]

FIG. 1 is an explanatory side view showing a housing of an example of a spindle device of the present invention broken away.

FIG. 2 is a vertical sectional view of a front portion of the spindle device.

FIG. 3 is a longitudinal sectional view of a rear portion of the spindle device.

FIG. 4 is an explanatory cross-sectional view showing the housing of the spindle device broken away at a position different from that of FIG.

5 is a partially enlarged view showing an enlarged main part of FIG.

[Explanation of symbols]

1 ... Spindle shaft, 2 ... Tool holder, 2a ... Tool, 3
… Housing, 5… Bearing, 14… Taper hole, 1
6 ... Drawbar, 21 ... Coil spring, 21a ... Fluid passage, 43 ... Machining liquid supply passage, 46 ... Spiral groove, 49 ... Cylindrical body, 58 ... Cooling jacket, 59 ... Cooling liquid supply passage, 60
… Coolant drain.

Claims (3)

[Scope of utility model registration request] Claim: What is claimed is: 1. A spindle shaft having a taper hole at a tip end thereof for removably inserting a tool holder by taper fitting, and an outer peripheral portion of the spindle shaft is covered to rotatably support the spindle shaft. A housing, a spindle motor internally mounted in the housing for rotationally driving the spindle shaft, and having a rotor integrally rotatably mounted on an outer peripheral surface of an intermediate portion of the spindle shaft; and a rear end portion of the spindle shaft. Through a through hole concentrically extending from the taper hole toward the tapered hole, and slidably inserted into the through hole from the rear end toward the tapered hole, and at a predetermined sliding position of the tool holder, Can be freely inserted into and removed from the tapered hole,
And at another predetermined sliding position, a rod-shaped draw bar having a locking portion at the tip portion for locking the tool holder inserted into the taper hole in a non-removable manner, and being inserted into the through hole, A coil spring externally attached to the drawbar and biasing the drawbar to the locking position of the tool holder, and a rear end of the spindle shaft to supply a working fluid to the tool holder inserted in the tapered hole. In a spindle device having a machining liquid supply path formed through the inside of the spindle shaft, the coil spring is provided inside the rotor of the spindle motor so as to extend in the axial direction thereof, and A spiral fluid passage is formed between the inner peripheral surface of the through hole of the spindle shaft and the outer peripheral surface of the draw bar, and the machining fluid supply passage has the spiral fluid passage in the middle thereof. Formed with a body passageway, a motor built-in spindle device characterized by using the cooled working fluid as the working fluid. 2. The spindle shaft is provided with a spiral groove formed on an outer peripheral surface supported by the housing, and a cylindrical body covering the spiral groove and fixed to the outer peripheral surface of the spindle shaft is interposed. 2. The machining fluid supply path is rotatably supported by a bearing provided inside the housing, and the machining fluid supply path is formed with the spiral groove in the middle thereof. Spindle device with built-in motor. 3. A cooling jacket, which encloses the stator of the spindle motor fixed to the inner peripheral surface of the housing and is formed in a spiral shape in the housing, and a cooling liquid is supplied to and discharged from the cooling jacket. The spindle device with a built-in motor according to claim 1, further comprising a cooling liquid supply passage and a cooling liquid discharge passage that are connected to and connected to the cooling jacket.