JPH07106534B2 - Spindle device with cooling liquid flowing through the spindle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a spindle device including a cooling means in a machine tool,
Particularly, the present invention relates to a spindle device in which a cooling liquid is circulated in the spindle in order to cool the spindle itself and efficiently cool the bearing portion from the inner ring side.

[Conventional technology]

Generally, a bearing of a main shaft of a machine tool or the like generates heat due to rotation, and therefore, lubricating oil that also serves as a cooling action is usually injected and supplied. However, in the case of a high-output, high-speed rotating spindle, a sufficient cooling effect cannot be obtained only by the cooling action of the lubricating oil.
Therefore, in order to supplement this cooling action, a method is generally used in which a cooling liquid is circulated through a housing supporting the bearing to cool the outer ring side of the bearing. Further, Japanese Utility Model Laid-Open No. 62-78245 discloses a technique in which a heat pipe is embedded in the main shaft to absorb heat generated from the bearing.

[Problems to be solved by the invention]

However, in recent years, there has been an increasing demand for faster spindles, and in some cases the above cooling methods are still insufficient.

Therefore, in order to solve such a problem, the present invention efficiently cools the bearing portion of the spindle of a machine tool or the like, increases the limit speed due to seizure of the bearing, and also cools the spindle itself to reduce the temperature of the spindle. This is intended to reduce the rise as much as possible and reduce the thermal expansion of the spindle.

[Means for solving problems]

In view of the above object, the present invention is a spindle device in which a spindle is rotatably supported by a housing via a bearing, and a cooling liquid supply means for supplying a cooling liquid from an externally provided cooling liquid source into the main shaft, The cooling liquid supplied into the main shaft is circulated in the axial direction of the main shaft to cool the main shaft itself and cooling means for cooling the bearing from the inner ring side of the bearing, and the cooling liquid flowing in the main shaft. There is provided a spindle device in which a cooling liquid is circulated in a spindle having a configuration including a cooling liquid recovery means for recovering a cooling liquid source provided outside.

[Action]

By circulating the cooling liquid in the main shaft, heat generated from the bearing inner ring can be efficiently absorbed, and the main shaft itself can be cooled, so that the thermal expansion of the main shaft can be minimized.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the accompanying drawings. 1 is a longitudinal sectional view of a spindle device according to the present invention, FIG. 2 is a transverse sectional view taken along the line II-II of FIG. 1, and FIG. 3 is another embodiment of the spindle device according to the present invention. .

First, referring to FIG. 1, the spindle 10 of the machine tool is a front bearing.
It is rotatably accommodated and held in the housing 14 via the 12 and the 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 nut 22 so as not to move in the front and rear direction (longitudinal direction). Has been done. Further, the rear bearing 36 is fixed by a similar bearing pressing nut 23 so as not to move in the longitudinal direction. The tip end of the main shaft 10 rotatably supported in this way is provided with a taper hole 24 that allows the tool holder 26 having the taper shank 28 to be drawn therein so as to rotate integrally with the main shaft 10. Center through hole 41 of spindle 10
A drawbar 34 is inserted through the drawbar 34, and the drawbar 34 is screwed into a stopper plate 40 that is slidable in the longitudinal direction in the center through hole 41, so that its central axis coincides with the central axis of the main shaft 10. Is centered and held. The draw bar 34 is configured such that the pull stud 32 fixed to the rear end of the taper shank 28 is pulled in through the ball collet 30 to integrally fix the tool holder 26 holding a tool (not shown) with the spindle 10. To do. The disc spring 38 is arranged in the outer peripheral space of the draw bar 34 (the space of the central through hole 41) in order to exert a force to pull in the tool holder 26. One end of the disc spring 38 presses the stopper plate 40 and the other end of the disc spring 38 presses the sleeve 33, and the sleeve 33 holds the ball collet 30. To unclamp the tool holder 26, a tool unclamp piston 58 provided behind the spindle 10 is used.

That is, the drawbar 34 is moved forward together with the ball collet 30 by pushing the stopper plate 40 forward (leftward in the drawing) against the spring force of the disc spring 38 by the hydraulic pressure from the hydraulic pressure source 52, and the tool holder Release 32 pieces of 26 pull studs. In this way, the tool can be removed together with the tool holder 26, and a new tool can be replaced with the fixed tool holder 26. A collar 74 fixed to the inner circumference of the main shaft 10 is disposed behind the stopper plate 40 described above.

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. Furthermore, a pipe line 46 for guiding the cutting fluid to the tool tip portion in cooperation with the spindle penetrating pipe 42 has a pull stud 32.
And is provided at the center of the tool holder 26. Such cutting fluid is supplied from the cutting fluid source 50 through the rotary joint 48,
It is supplied to a spindle penetrating pipe 42 that rotates together with the spindle 10.
While the tool is held on the spindle 10, the spindle penetrating pipe 42 is constantly pressed to the left 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, the cutting fluid can be supplied to the tip of the tool. When exchanging tools, the pipe advancing / retreating piston 54 is retracted to the right by the hydraulic pressure from the hydraulic pressure source 52 to retract the spindle penetrating pipe 42 from the contact position with the pull stud 32, and the tool exchanging is performed. Sometimes, the pull stud 32 and the main shaft penetrating pipe 42 are prevented from colliding with each other.

In the spindle device described above, a motor is incorporated in the spindle device in order to rotate the spindle 10. Rotor 64
Is fixed to the outer periphery of the main shaft 10 at an appropriate position, and the stator 62 is fixed to the inner periphery of the housing 14 so as to face the rotor 64.
Cooling of such a built-in type motor is an important issue, and its countermeasure will be described below.

First, a spiral cooling liquid passage 68 is provided on the outer periphery of the stator 62, and a cooling liquid is caused to flow from an external cooling liquid source 66 via an inlet hole 102 to cool the stator 62 from the outer peripheral side and through an outlet 104, Collect to the cooling liquid source 66. Next, rotor cooling means for cooling the rotor 64 will be described. A cooling liquid supply ring 72 is fixed inside the housing 14 near the rear end of the main shaft 10. A cooling liquid supply hole 70 is provided in the radial direction across the ring 72 and the housing 14, and the cooling liquid source described above is provided.
Coolant is introduced from 66. This cooling liquid does not necessarily have to be the same as the cooling liquid that cools the stator 62 described above, but the same cooling liquid is used in this embodiment.

The collar 74 fixed to the rear end portion of the main shaft 10 has an inner peripheral hole formed in a tapered shape, and the inner diameter increases as it goes to the left in the drawing. Therefore, the cooling liquid flowing from the cooling liquid supply ring 72 rotates together with the main shaft 10 and receives a centrifugal force, so that the cooling liquid is swept to the left with a large inner diameter. The stopper plate 40 is provided with a notch 75 at an appropriate position, communicates with the inner peripheral hole of the collar 74, and is a space in the center through hole 41 of the main shaft 10 described above, which is a drawbar.
It also communicates with the outer peripheral annular space 76 of 34. Therefore, the cooling liquid that has passed through the collar 74 flows into the annular space 76 in which the disc spring 38 is arranged. On the other hand, in the main shaft 10, the rotor
An appropriate number of cooling liquid return conduits 78 are formed near the inner circumference of the rotor 64, and communicate with the annular space 76 near the left end of the rotor 64. It is preferable that the return line 78 has a radial position that gradually increases as the return line 78 advances in the direction in which the cooling liquid flows (to the right). With such a configuration, the cooling liquid smoothly flows to the right under the action of centrifugal force caused by rotation. Due to the action of this cooling liquid, the rotor 64 is efficiently cooled from its inner peripheral side. The cooling liquid that has cooled the rotor 64 in this way is
It flows outward from an outlet hole 79 which is provided in the radial direction of the main shaft 10 and communicates with the return conduit 78, flows into a hole 80 of a bracket member 81 fixed to the housing 14, and finally a cooling liquid source 66. Will be collected. At this time, if the cooling liquid is sucked outward from the outlet hole 79, it becomes easy to circulate.

Pressurized air is supplied from an air pressure source 82 through an air sealing hole 84 in order to prevent liquid leakage when the cooling liquid flows out from the rotating main shaft 10 to the stationary housing 14. The pressurized air also serves to prevent the cooling liquid supplied from the hole 98R described later from entering between the bracket member 81 and the rotary main shaft 10.

Next, the cooling means for the front bearing 12 will be described. Although not shown, the outer ring side of the front bearing 12 is cooled by a cooling liquid flow path means provided in a stationary housing 14 supporting the outer ring. The supply source of this cooling liquid may be the above-mentioned cooling liquid source 66, the flow path means may be the same as the above-mentioned spiral cooling liquid passage 68, and an appropriate number of flow paths provided in the longitudinal direction. May be included. Although not shown, the lubricating oil is supplied between the outer ring and the inner ring of the front bearing 12 for cooling as well.

The front bearing 12 is also cooled from the inner ring side by the means described below. A part of the cooling liquid that has flowed into the annular space 76 is arranged near the inner periphery of the front bearing 12 described above (four in this embodiment) at an equal angle, and the bearing cooling liquid pipeline is provided.
It is flowing into 86 (outward route). As can be seen from FIG. 2, the bearing coolant liquid conduit 86 communicates with the bearing coolant liquid return conduit (return passage) 88 having a large radial position at the front end portion of the main shaft 10 via the connection passage 110. is doing. Since the radial position dimension of the connection passage 110 increases in the direction in which the cooling liquid flows, the cooling liquid smoothly flows by the action of the centrifugal force. Not only the above-mentioned connecting passage, but also the bearing cooling liquid conduit 86 and the bearing cooling liquid return conduit 88 preferably have a configuration in which the radial position dimension of the conduit gradually increases along the direction in which the cooling liquid flows. In this way, the cooling liquid that has cooled the front bearing 12 from the inside thereof is recovered by the aforementioned cooling liquid source 66. Also at this time, if it is sucked, it becomes easy to collect. Then, as in the case of collecting the cooling liquid of the rotor 64 described above, pressurized air is supplied from the air pressure source 82 through the air sealing hole 108 to prevent the cooling liquid from leaking. In addition, this pressurized air is
The coolant supplied from 98L is also prevented from entering between the bracket member 106 and the rotary main shaft 10.

Further, in order to cool the motor efficiently, pressurized air is made to flow from the air pressure source 82 into the facing gap 94 between the rotor 64 and the stator 62. Therefore, an appropriate number of radial holes 90 are circumferentially provided 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 is formed by forming a center portion of the rotor 64 facing the hole 90 as a bottom portion having the smallest radius, and having a tapered surface 92 whose outer diameter gradually increases as it goes in the left and right end surface directions of the rotor 64. ing. Therefore, the cross-sectional area of the facing gap 94 between the roller 64 and the stator 62 becomes smaller as approaching each end face of the rotor 64, and the flow velocity of the pressurized air gradually increases. This pressurized air is applied to the outer peripheral portion of the rotor 64 and the stator.
A seal is provided not only to cool the inner peripheral portion of 62 but also to prevent the cooling liquid flowing to cool both ends of the motor, which will be described later, from entering into the facing gap 94 between the rotor 64 and the stator 62 from both ends 96 of the gap 94. Also has the effect of doing. In order to increase the sealing effect, the outer diameter of the rotor 64 is formed by the tapered surface 92 so that the outflow speed is maximized at both ends 96 of the gap 94 as described above.

Next, cooling liquid is supplied from the cooling liquid source 66 through the radial holes 98L and 98R provided in the housing 14 to cool the ends of the stator 62 and the rotor 64, and the ends of the stator 62 and the rotor 64 are cooled. After that, the cooling liquid source 66 is recovered from the outlet holes 100L and 100R. At this time, in order to prevent the cooling liquid from entering the inside of the motor, in addition to causing the pressurized air to flow out from the facing gap 94 between the rotor 64 and the stator 62 to seal the stator 62 and the rotor 64 as described above. Is impregnated with epoxy resin. At this time, the cooling liquid flowing in from the radial holes 98L, 98R directly contacts the outer periphery of the main shaft 10 and helps prevent the heat generation of the main shaft.

As described above, the front bearing 12 and the motor are not only cooled from the outside by providing a cooling liquid flow path in the housing in a stationary state,
By positively flowing the cooling liquid into the rotating spindle 10, not only the bearing and the motor can efficiently absorb heat, but also the spindle 10 itself can be directly cooled.

In contrast to the first embodiment described above, FIG. 3 shows a second embodiment. In the second embodiment, the cutting fluid to be supplied to the machining area is not structured to pass through the spindle 10, and for example, a cutting oil nozzle piped outside the spindle head or other not shown supply means. Supplied by. Therefore, there is no pipe 46 that penetrates the spindle penetrating pipe 42 for supplying cutting fluid and the tool holder 26 shown in FIG. Instead of the spindle penetrating pipe 42 for supplying the cutting fluid, in FIG. 3, a conduit 142 for supplying the cooling fluid is provided.
Is arranged at the center of the main shaft 10 penetrating the drawbar 34, and sends the cooling liquid supplied from the cooling liquid source 66 to the conduit 142 via the rotary joint 48. The cooling liquid sent to the conduit 142 passes through a hole 116 that radially penetrates the conduit 142 and the drawbar 34, and a collar 112 having a hole communicating with the hole 116, and the first embodiment Into the same coolant return line 78 as described above. Further, a part of the cooling liquid in the conduit 142 flows into the same bearing cooling liquid conduit 86 as that described in the first embodiment from the tip of the conduit 142 via the conduit 114 fixed in the radial direction. To do.

Regarding the difference between the first embodiment and the second embodiment, in addition to the above matters, a pipe advancing / retreating piston 54 for advancing / retreating the spindle penetrating pipe 42 shown in FIG. 1, a coil spring 56, and a radial thrust bearing 57. Etc. are not present in the second embodiment, but both are the same with respect to the other main configuration.

The first and second embodiments have been described above. Among them, the cooling liquid supplied to the main shaft 10 is used not only for cooling the front bearing 12 but also for cooling the rotor 64 of the motor. However, for the purpose of the present invention, it is obvious that the cooling of 64 is not necessarily required, and the structure may be such that only the cooling from the inner ring side of the front bearing 12 is supplied. Furthermore, each of the rear bearing 36 examples is possible as well.

〔The invention's effect〕

As is clear from the above description, according to the present invention, since the cooling liquid is directly circulated in the main shaft, the effect of absorbing heat from the bearing that contacts and supports the main shaft is high, and the limit due to seizure of the bearing It is possible to prevent the speed from decreasing. The main shaft itself can be cooled by circulating the cooling liquid, and the temperature rise of the main shaft can be reduced as much as possible, so that the thermal expansion of the main shaft is suppressed. Therefore, if it is applied to the spindle of a machine tool, the machining accuracy of the work can be improved.

[Brief description of drawings]

1 is a longitudinal sectional view of a spindle device according to the present invention, FIG. 2 is a transverse sectional view taken along the line II-II of FIG. 1, and FIG. 3 is another embodiment of the spindle device according to the present invention. 10 …… spindle, 12 …… front bearing, 14 …… housing, 34…
… Drawbars, 38 …… Disc springs, 62 …… Stator, 64 ……
Rotor, 68 ... spiral cooling liquid passage, 76 ... annular space, 78
...... Coolant return line, 84 …… Air seal hole, 86 …… Bearing coolant line (forward), 88 …… Bearing coolant return line (return line), 94 …… Gap between rotor and stator , 108 ……
Hole for air seal.

Claims (5)

[Claims] 1. A main shaft device in which a main shaft is rotatably supported by a housing via a bearing, and a cooling liquid supply means for supplying a cooling liquid into the main shaft from a cooling liquid source provided outside; Cooling means for circulating the supplied cooling liquid in the axial direction of the main shaft to cool the main shaft itself and also to cool the bearing from the inner ring side of the bearing, and the cooling liquid flowing in the main shaft to the outside are provided. A spindle device in which the coolant is circulated in the spindle, comprising: a coolant recovery means for recovering the coolant in the coolant source. 2. The cooling liquid supply means includes an annular gap extending in an axial direction formed by a tool clamp drawbar inserted into an axis of the main shaft and an inner circumference of the main shaft from a rear side of the main shaft. Supplying the cooling liquid, the cooling means is constituted by a flow path that extends in the main shaft in proximity to the inner peripheral side of the bearing from an intermediate position in the axial direction that communicates with the annular gap,
The spindle device according to claim 1, wherein the cooling liquid recovery means discharges the cooling liquid flowing through the flow path from the end of the flow path to the outside of the main shaft. 3. The cooling liquid supply means supplies the cooling liquid from the rear of the main shaft to an axial flow passage provided in the shaft center of a drawbar for tool clamp inserted in the shaft center of the main shaft, The cooling means is composed of a flow path that extends in the main shaft in proximity to the inner peripheral side of the inner ring of the bearing from the axial direction flow path in communication with the axial flow path, and the cooling liquid recovery means, The spindle device according to claim 1, wherein the cooling liquid that has flowed through the flow path is discharged from the end of the flow path to the outside of the main shaft. 4. The outward path extending in the axial direction of the main shaft, wherein the flow path of the cooling means is in the axial direction of the main shaft for returning the cooling liquid via a connecting path at the end position of the outward path. And a radial path extending from the axial center of the main shaft as the connecting path progresses in a direction in which the connecting path communicates with the return path from the end position of the outward path. A spindle device in which a cooling liquid is circulated in the spindle according to item 2 or 3. 5. The coolant in the spindle according to claim 4, wherein the forward path and the return path are arranged such that their radial positions from the axial center of the spindle move away from each other in the direction in which the cooling fluid flows. Circulated spindle device.