JPH0192048A - Motor built-in type main spindle device equipped with cooling means - Google Patents

Abstract

PURPOSE:To reduce the thermal expansion of a main shaft and obtain the small-sized high speed title device having a high output by installing a stator cooling means for cooling a stator and a rotor cooling means for cooling a rotor from the inner peripheral side by the cooling liquid which circulates in the main shaft. CONSTITUTION:A spiral cooling liquid passage 68 is formed on the outer periphery of a stator 62, and cooling liquid is allowed to flow from an outside cooling liquid source 66 through an inlet hole 102, and cools a stator 62 from an outer peripheral side and is recovered into the cooling liquid source 66, passing through an outlet 104. Further, the cooling liquid is allowed to flow into a cooling liquid feeding hole 70 from the cooling liquid source 66, and the cooling liquid which flows into a cooling liquid feeding ring 72 turns together with a main shaft 10, and is applied with a centrifugal force, and the cooling liquid is allowed to flow in the left direction to the part having a large inside diameter. Then, the liquid flows into an annular space in which a belleville spring 38 is arranged. While, in the main shaft 10, a cooling liquid return conduit 78 communicates to the above-described annular space closely to the left edge of a rotor 64, and in said conduit 78, the radius position gradually increases in the direction (rightward direction) of flow of the cooling liquid, and the cooling liquid flows smoothly, and the rotor 64 is cooled from the inside.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spindle device with a built-in motor, and more particularly to a spindle device with a built-in motor provided with cooling means for increasing the efficiency of the motor.

[Conventional technology]

Generally, in machine tools, built-in motors are used for the purpose of downsizing the spindle head, reducing spindle inertia, increasing speed, reducing spindle vibration and noise, and reducing the number of parts. A spindle device with a spindle is used. For example, JP-A-62-107903 discloses a spindle device with a built-in motor, the spindle of which is rotatable relative to the spindle head and slidable in the axial direction. 0 This publication does not disclose motor cooling, but cooling is generally essential for high-output built-in motors, and conventionally cooling fluid is used in the housing that houses the stator or in the cooling pipes buried inside the stator. It was cooled by circulating the water. Alternatively, if the amount of heat generated was small, cooling was done by natural heat radiation using fins or forced air cooling.

[Problem that the invention seeks to solve]

The higher the output and the smaller the motor, the greater the amount of heat generated.In recent years, small-sized built-in motors with high output have become so powerful that the conventional liquid cooling of only the outside of the stator does not provide sufficient cooling effect. It's starting to be demanded. In order to meet these demands, for example, even if we apply the technology disclosed in Japanese Utility Model Application Publication No. 62-78245 in which a heat pipe is embedded in the main shaft for heat absorption in the main shaft bearing part, the amount of heat generated by a high-output motor is low. In the case of a large value, a sufficient endothermic effect cannot necessarily be obtained.

Therefore, in order to solve these problems, the present invention cools the inside of the motor sufficiently, thereby reducing the thermal expansion of the spindle and improving the machining accuracy of the workpiece. The purpose is to provide a small, high-speed, high-output spindle device with a built-in motor.

[Means for solving problems]

In view of the above object, the first invention is such that a rotor is attached to the outer periphery of a main shaft which is rotatably supported by a housing, and a stator is attached to the inner periphery of the housing to face the rotor and rotate the main shaft. In the motor built-in spindle device, a stator cooling means for cooling the stator;
Provided is a motor built-in spindle device having a cooling means, characterized in that the rotor is cooled from the inner circumferential side of the rotor using a cooling liquid circulated within the main spindle.

The second aspect of the present invention is such that a gas cooling means is added to the first aspect of the present invention for flowing pressurized cooling gas into the opposing gap between the stator and the rotor.

A third aspect of the present invention is the second aspect of the present invention in which an end cooling means for flowing another cooling liquid to cool the ends of the stator and rotor is added.

[For production]

In the first invention, the motor is cooled by liquid not only from the stator side but also from the inner peripheral side of the rotor, so that the heat absorption effect of the motor is enhanced. In the second invention, since the cooling effect is added to the inner periphery of the stator and the outer periphery of the rotor, the cooling effect of the motor is further enhanced. Furthermore, in the third invention, the end portions of the stator and rotor are also cooled by the liquid, so that the cooling effect is further enhanced. Although the liquid flowing at the ends of the stator and rotor according to the third aspect of the invention tends to enter the opposing gap between the stator and rotor, this entry can be prevented by the outflow action of the pressurized cooling gas.

〔Example〕

The present invention will be described in more detail below based on embodiments shown in the accompanying drawings. FIG. 1 is a longitudinal cross-sectional view of the spindle device according to the present invention, FIG. 2 is a cross-sectional view taken along arrow line nn in FIG. 1, and FIG.
The figure shows another embodiment of the spindle device according to the present invention.

First, referring to FIG. 1, a main shaft 1° of a machine tool is housed and held in a rotatable housing 14 via a front bearing 12 and a rear bearing 36. The front bearing 12 is separated by an inner ring collar 18 and an outer ring collar 20, and the front and rear ends of the bearing 12 are fixed by a bearing retainer 16 and a bearing retainer napft 22 so as not to move in the front and rear direction (longitudinal direction). has been done. Furthermore, the rear bearing 36 is secured against longitudinal movement by a similar bearing retaining nut 23. A tapered hole 24 is provided at the tip of the main spindle 10 rotatably supported in this manner, into which a tool holder 26 having a tapered shank 28 can be drawn and rotated integrally with the main spindle 10. A drawbar 34 is inserted into the center through-hole 41 of the main shaft 10, and the drawbar 34 is screwed into a stopper 40 that is slidable in the longitudinal direction within the center through-hole 41, so that the center axis of the drawbar 34 can be adjusted. is held centered so that it coincides with the central axis of the main shaft 10. This drawbar 34 allows the tool holder 26 holding a tool (not shown) to be integrated with the main shaft 10 by pulling in the pull stand 32 fixed to the rear end of the taper shank 28 via the ball collet 30. A fixing disc spring 38 is disposed in the outer circumferential space of the drawbar 34 (the space of the center through hole 41) in order to apply a force for drawing the tool holder 26. One end of the disc spring 38 has a stopper 4
0, and the other end presses a sleeve 33, which holds the ball collet 30. To unclamp the tool holder 26, a tool unclamp piston 58 provided at the rear of the main shaft 10 is used.
use.

That is, the drawbar 34 is moved forward together with the ball collet 30 by pushing the catch 40 forward (to the left in the figure) against the spring force of the disc spring 38 by the hydraulic pressure from the hydraulic source 52, and the tool is moved forward. Release the pull stand 32 portion of the holder 26. In this way, the tool can be removed together with the tool holder 26, and can be replaced with a new tool holder 26 to which a new tool is fixed. Behind the above-mentioned clasp 40 is the main shaft 10.
A collar 74 fixed to the inner periphery is disposed.

A spindle penetrating pipe 42 having a through hole 44 for supplying cutting fluid is disposed along the central axis of the spindle device configured as described above. Further, a conduit 46 is provided at the center of the pull stud 32 and the tool holder 26 for cooperating with the spindle penetrating vibrator 42 to guide cutting fluid to the tool tip. Such cutting fluid is supplied from a cutting fluid source 50 via a rotary shaft 48 to a main shaft penetrating pipe 42 that rotates together with the main shaft 10. While the tool is held on the main shaft 1o, the main shaft penetrating pipe 42 is constantly pressed leftward by the coil spring 56 via the radial thrust bearing 57, and is in contact with the end surface of the pull stud 32. In this way, it is possible to supply cutting fluid to the tool tip. When changing tools, use the aforementioned hydraulic power source 52.
The piston 54 for advancing and retracting the pipe is moved back to the right by the hydraulic pressure of the head, and the main shaft penetrating pipe 42 is retreated from the contact position with the pull stand 32, so that the pull stand 32 and the main shaft penetrating pipe 42 collide when exchanging tools. prevent

In the spindle device described above, a motor is incorporated in the spindle bag device in order to rotate the spindle 1o. A rotor 64 is fixed to the outer periphery of the main shaft 10 at an appropriate position, and the rotor 64 is
A stator 62 is fixed to the inner periphery of the halo ring 14 so as to face the stator 4 . Cooling is an important issue in such built-in motors, and countermeasures will be explained below.

First, a spiral coolant passage 68 is provided on the outer periphery of the stator 62, and the coolant flows from an external coolant source 66 through the inlet hole 102 to cool the stator 62 from the outer periphery side and passes through the outlet 104. Collected to coolant source 66 . Next, the rotor cooling means for cooling the rotor 64 will be explained. A coolant supply ring 72 is fixed inside the housing 14 close to the rear end of the main shaft IO. A coolant supply hole 70 is provided in the radial direction between the ring 72 and the housing 14, through which coolant flows from the above-mentioned coolant source 66. Although this cooling liquid does not necessarily have to be the same as the cooling liquid that cools the stator 62 described above, in this embodiment, the same cooling liquid is used.

The above-mentioned collar 74 fixed to the rear end of the main shaft 10 has a tapered inner circumferential hole, and the inner diameter becomes larger toward the left in the figure. Therefore, the coolant flowing in from the coolant supply ring 72 rotates together with the main shaft 10 and is subjected to centrifugal force, so that it is pushed toward the left where the inner diameter is larger. The above-mentioned clasp 40 has a notch 7 at a suitable place.
5, which communicates with the inner circumferential hole of the collar 74, and also communicates with the outer circumferential annular space 76 of the drawbar 34, which is a space within the center through hole 41 of the main shaft 10 mentioned above. . Therefore, the coolant that has passed through the collar 74 is
It flows into the annular space 76 in which the disc spring 38 is arranged. On the other hand, an appropriate number of coolant return pipes 78 are formed in the main shaft 10 in close proximity to the inner periphery of the rotor 64, and communicate with the annular space 76 near the left end of the rotor 64.

It is preferable that the radial position of the return pipe 78 gradually increases as it advances in the direction in which the coolant flows (rightward).

With this configuration, the coolant flows smoothly to the right under the action of centrifugal force that accompanies rotation. Due to the action of this cooling fluid, the rotor 64 is efficiently cooled from its inner peripheral side. The coolant that has cooled the rotor 64 in this manner flows outward from an outlet hole 79 provided in the radial direction of the main shaft 10 and communicating with the return pipe 78, and enters a hole 80 of a bracket member 81 fixed to the housing 14. and is ultimately collected in the coolant source 66. At this time, if the cooling liquid is sucked outward from the outlet hole 79, circulation becomes easier.

A stationary housing 14 from a rotating main shaft 10
Pressurized air is supplied from an air pressure source 82 through an air seal hole 84 in order to prevent liquid leakage when the cooling liquid flows out. This pressurized air is supplied from a hole 98R to be described later, and the cooling liquid is connected to the bracket member 81 and the rotating main shaft l.
It also plays the role of preventing intrusion between O and O.

A portion of the cooling liquid that has flowed into the annular space 76 is distributed in a plurality of (four in this embodiment) near the inner circumference of the front bearing 12.
It flows into equiangularly arranged bearing coolant lines 86 . As can be seen from FIG. 2, the bearing coolant line 86 communicates with a bearing coolant return line 88 having a large radial position at the front end of the main shaft 10 via a connecting passage 110. .

Since the radial position of the connecting passage 110 increases in the direction in which the coolant flows, the coolant flows smoothly due to the action of centrifugal force. It is preferable that not only the above connection passage but also the bearing coolant pipe 86 and the bearing coolant return pipe 88 have a radial position dimension that gradually increases along the direction in which the coolant flows. Thus the front bearing 1
The cooling liquid that cooled the 2 from the inside is supplied to the aforementioned cooling liquid source 66.
will be collected. At this time, suction will also make it easier to collect. As in the case of recovering the coolant from the rotor 64 described above, pressurized air is supplied from the air pressure source 82 through the air seal hole 108 to prevent leakage of the coolant. Furthermore, this pressurized air also prevents the cooling liquid supplied from a hole 98L, which will be described later, from entering between the bracket member 106 and the rotating main shaft IO.

Further, in order to efficiently cool the motor, pressurized air is caused to flow from the air pressure source 82 into the opposing gap 94 between the rotor 64 and the stator 62. For this purpose, an appropriate number of radial holes 90 are provided in the circumferential direction across the housing 14 and the stator 62 so as to face the center position of the rotor 64. The outer periphery of the rotor 64 has a tapered surface 92 whose outer diameter gradually increases toward the left and right end surfaces of the rotor 64, with the bottom having the smallest radius located at the center of the rotor 64 facing the hole 90. ing. Therefore, the cross-sectional area of the opposing gap 94 between the rotor 64 and the stator 62 becomes smaller as it approaches each end face of the rotor 64, and the flow velocity of the pressurized air gradually increases. This pressurized air not only cools the outer periphery of the rotor 64 and the inner periphery of the stator 62, but also coolant flowing to cool both ends of the motor, which will be described later, flows into the opposing gap 94 between the rotor 64 and the stator 62. It also acts as a seal to prevent intrusion from both ends 96 of the gap 94. In order to enhance this sealing effect, the outer diameter of the rotor 64 is configured with a tapered surface 92 so that the outflow velocity is maximum at both ends 96 of the gap 94 as described above.

Next, radial holes 98L and 98R are provided in the housing 14 to cool each end of the stator 62 and rotor 64.
coolant is supplied from a coolant source 66 through the stator 6.
2 and each end of the rotor 64, the outlet hole 100L is
and 100R to the cooling liquid source 66. At this time, in order to prevent the coolant from entering the inside of the motor, pressurized air is flowed out from the opposing gap 94 between the rotor 64 and the stator 62 to seal the gap 94 between the stator 62 and the rotor 64 as described above. is impregnated with epoxy resin. At this time, the coolant flowing in from the radial holes 98L and 98R directly covers the outer periphery of the main shaft 10, thereby helping to prevent the main shaft from generating heat.

As described above, the motor is cooled from the outer periphery, the inner periphery, and both ends with the cooling liquid, and furthermore, the entire motor is cooled by flowing pressurized air, which also serves as a seal, into the opposing gap 94 between the rotor 64 and the stator 62. Can be done.

In contrast to the first embodiment described above, a second embodiment is illustrated in FIG. In the second embodiment, the cutting fluid supplied to the machining area is not structured to pass through the spindle 10, but other supply means (not shown) such as a cutting oil nozzle piped outside the spindle head, etc. are used. Supplied by Therefore, there is no pipe line 46 that passes through the spindle penetrating vibe 42 and tool holder 26 for supplying cutting fluid as shown in FIG. In place of the spindle penetrating vibrator 42 for supplying cutting fluid, in FIG. The coolant is passed through the rotary joint 48 to the conduit 142.
send to. The cooling liquid sent into the conduit 142 flows through the hole 1 that passes through the conduit 142 and the drawbar 34 in the radial direction.
16, and a collar 112 having a hole communicating with the hole 116.
and into the same coolant return line 78 as described in the first embodiment. A portion of the coolant in the conduit 142 is routed from the tip of the conduit 142 through a radially fixed conduit 114 to the same bearing coolant conduit 86 as described in the first embodiment. Inflow.

Regarding the differences between the first embodiment and the second embodiment, in addition to the above-mentioned matters, there are a piston 54 for advancing and retreating the pipe for advancing and retreating the main shaft penetrating vibe 42 shown in FIG. 1, a coil spring 56, and a radial thrust bearing 57. etc. are not present in the second embodiment, but the other main structures are the same.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a main shaft device with a built-in motor, not only the stator is cooled, but also the cooling liquid is circulated around the main shaft to cool the rotor from the inner periphery. The heat absorption rate from the motor is high, and by directly liquid cooling the motor's stator and the end of the rotor, and by flowing cooling gas into the gap between the rotor and stator, the outer circumference of the rotor and the inner part of the stator can be cooled. Since it can also be cooled from the periphery, the heat absorption rate from the negative stage and the motor increases.

When the heat absorption rate increases in this way, the usable limit of the motor improves, it becomes possible to use a small and compact motor, and furthermore, it becomes possible to reduce the thermal expansion of the main shaft. In turn, the machining accuracy when machining the spindle device Mowork of the present invention is improved. Furthermore, by downsizing the motor, not only the spindle device as a whole becomes more compact, but also the rotational inertia of the spindle is reduced, resulting in a spindle device that is agile in the rise and fall of rotation, and improves workpiece machining efficiency.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a spindle device according to the present invention, FIG. 2 is a cross-sectional view taken along arrow line nn in FIG. 1, and FIG. 3 is another embodiment of the spindle device according to the present invention. lO...Main shaft, 12...Front bearing, 14
...Housing, 34...Drawbar, 38.
... Disc spring, 62... Stator, 64...
Rotor, 68... Spiral coolant passage, 76...
- Annular space, 78...Cooling liquid return pipe, 84...
・Air seal hole, 86... Bearing coolant pipe, 88... Bearing coolant return pipe, 94... Opposing gap between rotor and stator, 108...
・Air seal hole.

Claims (1)

[Scope of Claims] 1. A built-in motor type in which a rotor is attached to the outer periphery of a main shaft rotatably supported by a housing, and a stator is attached to the inner periphery of the housing to face the rotor and rotate the main shaft. A cooling means for a main shaft device, comprising: a stator cooling means for cooling the stator; and a rotor cooling means for cooling the rotor from an inner circumferential side using a cooling liquid circulated within the main shaft. Spindle device with built-in motor. 2. The rotor cooling means supplies the cooling liquid from the rear of the main spindle to an annular gap between the tool clamp drawbar inserted into the axial center of the main spindle and the inner periphery of the main spindle, and Cooling according to claim 1, characterized in that the cooling liquid is circulated through a return conduit provided outside the annular gap and in the main shaft adjacent to the inner peripheral side of the rotor. A spindle device with a built-in motor. 3. The rotor cooling means supplies the cooling liquid from the rear of the main spindle to an axial hole provided in the axial center of a tool clamp drawbar inserted into the axial center of the main spindle, and 2. A motor-built-in spindle device comprising a cooling means according to claim 1, wherein said cooling liquid is circulated through a return conduit provided in said spindle adjacent to an inner peripheral side of said rotor. 4. The rotor cooling means is configured such that the radial position of the rotor cooling means becomes farther away from the axis of the main shaft as the pipe line for circulating the cooling liquid advances in the direction in which the cooling liquid flows. A built-in motor type spindle device equipped with the cooling means described in 2. 5. A built-in motor type spindle device in which a rotor is attached to the outer periphery of a main shaft rotatably supported by a housing, and a stator is attached to the inner periphery of the housing facing the rotor to rotate the main shaft, wherein the stator a stator cooling means for cooling the rotor from an inner circumferential side of the rotor using a cooling liquid circulated within the main shaft; What is claimed is: 1. A spindle device with a built-in motor, comprising: a gas cooling means that cools the inner periphery of the stator and the outer periphery of the rotor by flowing gas. 6. The gas cooling means is configured to provide a pressurized gas supply hole opening on the inner peripheral surface of the stator toward the gap between the stator and the rotor, and reduce the outer diameter of the rotor in the vicinity of the pressurized gas supply hole. A built-in motor spindle device comprising a cooling means as set forth in claim 5, wherein the outer diameter of the rotor increases as it approaches the end face of the rotor. 7. In a motor-built-in spindle device in which a rotor is attached to the outer periphery of a main shaft rotatably supported by a housing, and a stator is attached to the inner periphery of the housing to face the rotor and rotates the main shaft, the stator a stator cooling means for cooling the rotor from an inner circumferential side of the rotor using a cooling liquid circulated within the main shaft; It is characterized by comprising: a gas cooling means for cooling the inner periphery of the stator and the outer periphery of the rotor; and an end cooling means for causing another cooling liquid to flow along the end surfaces of the stator and rotor. A built-in motor spindle device with cooling means. 8. A motor built-in spindle device equipped with a cooling means according to claim 7, wherein the stator and rotor are both impregnated with resin to prevent the other cooling liquid from entering. 9. The gas cooling means is configured to provide a pressurized gas supply hole opening on the inner peripheral surface of the stator toward the gap between the stator and the rotor, and reduce the outer diameter of the rotor in the vicinity of the pressurized gas supply hole. A built-in motor spindle device comprising a cooling means according to claim 7 or 8, wherein the outer diameter of the rotor increases as it approaches the end face of the rotor.