JP2001310210A - Delivery shaft cooling system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain demanded working precision even when manual after- processing is not applied by restraining thermal expansion due to cutting heat generated at the time of working. SOLUTION: This delivery shaft cooling system is furnished with a cooling liquid supply means to supply cooling liquid to the inside of a delivery shaft 32 from a cooling liquid source 34 provided outside, a cooling means to cool the delivery shaft 32 itself by circulating the cooling liquid supplied to the delivery shaft 32 in the axial direction of the delivery shaft 32 and a cooling liquid recovery means to recover the cooling liquid circulated in the inside of the delivery shaft 32 in the cooling liquid source 34 provided outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle cooling device for cooling a pay-out shaft in a main shaft of a horizontal boring machine of a machine tool. More particularly, a cooling liquid is passed through the pay-out shaft in order to cool the pay-out shaft from the inside. It relates to a cooling device.

[0002]

2. Description of the Related Art In general, a horizontal boring machine is mainly composed of a housing 1, a main shaft 2 as shown in FIG.
The housing 1 is fixed, the main shaft 2 is rotatable only, and the payout shaft 3 is rotatable and payable. 5, 16 and 17 are rotary bearings, 7 is a ball screw, 8 is a motor, 9 is a hydraulic unit, 10 is a key that feeds out the rotational force of the main shaft 2 to the shaft 3, 11 is a key groove,
Reference numeral 12 denotes a spur gear with two rotations of the main shaft.

At the time of processing the workpiece 13 shown in FIG. 4, a not-shown table moving and feeding shaft 3 is extended, rotates together with the main shaft 2, and performs a predetermined processing. At this time, the cutting heat generated is removed by the cutting fluid discharged from the cutting fluid nozzle 4 at the tip of the housing.

[0004]

However, since the machining point 15 is located deep inside the workpiece 13, it is difficult to properly apply the cutting fluid to the tool 14 and the machining point 15 at the tip of the feeding shaft 3, and the cutting heat Thereby, the workpiece 13 and the feeding shaft 3 thermally expand. Regarding the pay-out shaft 3, an elongation of about 200 μm occurs at a rotation speed of 2500 / min. For this reason, a step is formed in the workpiece 13 in the feeding axis direction, and the workpiece 13 cannot be used for mold processing requiring accuracy, and requires post-processing by hand or another machine. In order to obtain the required processing accuracy, it is necessary to reduce the elongation of the feeding shaft 3 to about 1/10. Thus, the current situation always requires human resources,
It is not said to be an easy-to-use machine and cannot respond to voices that require high-speed rotation and high precision.

[0005] Accordingly, in view of the conventional disadvantages, the present invention suppresses thermal expansion due to cutting heat generated during processing, and enables a feed shaft capable of maintaining required processing accuracy without performing a manual post-process. It is intended to provide a cooling device.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a spindle cooling device having a pay-out shaft in a main shaft rotatably supported by a housing via a bearing.
Cooling liquid supply means for supplying a cooling liquid into the pay-out shaft from a cooling liquid source provided outside, and flowing the cooling liquid supplied to the pay-out shaft in the axial direction of the pay-out shaft to cool the pay-out shaft itself Cooling means, and a cooling liquid collecting means for collecting the cooling liquid flowing in the feeding shaft to a cooling liquid source provided on the outside, and circulating the cooling liquid in the feeding shaft. This is an extension shaft cooling device.

In a second aspect of the present invention, in the first aspect, the payout shaft has a cooling groove dug in an axial direction along a circumferential direction of a front end surface portion.

By using such an apparatus, the thermal expansion of the feeding shaft caused by the cutting heat generated during processing can be suppressed, so that the required processing accuracy can be maintained almost without any post-processing. This makes it possible to provide a proper spindle cooling device.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 is an overall view including a spindle head 31 of a machine tool to which an extension shaft structure according to the present invention is applied, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. 3 shows a positional relationship between a workpiece and an extension shaft. FIG. In each drawing, the same parts as those in FIGS. 4 and 5 described above are denoted by the same reference numerals.

In FIG. 1, reference numeral 32 denotes a pay-out shaft in which the structure of the present invention is applied to the pay-out shaft 3 described in the prior art, 33 denotes a bush for fitting the outside of the pay-out shaft 32, and 34 denotes a coolant in the pay-out shaft 32. A cooling device having a cooling liquid source to be supplied, 35 is a cooling liquid supply passage which linearly penetrates the inside of the payout shaft 32, and 36 is a cooling liquid discharge passage which penetrates linearly inside the payout shaft 32 similarly to 35. . Reference numeral 37 denotes a spiral groove dug in the axial direction along the circumferential direction of the cylindrical tip surface portion of the payout shaft 32. The bush 33 is fitted around the outer periphery of the spiral groove 37, and the coolant flows through this groove. First, the overall configuration will be described in detail with reference to FIG.

The main shaft 2 is rotatably held by the housing 1 via a front rotary bearing 5 and a rear rotary bearing 16. A pay-out shaft 32 is inserted into the main shaft 2, and
The rotational force of the main shaft 2 is also transmitted to the pay-out shaft 32.
The rotational force of the main shaft 2 is generated by rotation of a spur gear 12 meshing with a gear connected to a rotary electric motor (not shown) via a key 10 and a key groove 11. The movement of the feeding shaft 32 is performed by the spindle head 31.
The ball screw 7 is fixed by a ball nut 18 screwed to the ball screw 7 by driving a motor 8 located at the rear end of the ball screw 7. Movement is performed integrally with 19.

The delivery shaft 32 is cooled by a cooling device 34 having a coolant source.
Cooling becomes possible by passing through the coolant supply passage 35, the spiral groove 37, and the coolant discharge passage 36.

The spiral groove 37 is provided so that the coolant can flow even when the feeding length of the feeding shaft 32 from the tip of the main shaft 2 is maximized.
From the tip to the key groove 11 tip, the coolant is dug in the cylindrical surface portion, and flows between the bush 33 and the outer circumference thereof. The transmission of the cutting heat to the portion having the keyway 11 is small, and the heat can be exhausted from this portion by the cooling passages 35 and 36 that pass straight through the inside of the feeding shaft 32.

When the motor 8 is started in the above configuration, the ball screw 7 connected to the motor 8 rotates, and the rotary bearing support 19 moves via the ball nut 18. Thus, the payout shaft 32 integrated with the rotary bearing support 19 can be moved. After the feeding shaft 32 reaches a predetermined position, the tool 14 is loaded on the feeding shaft 32, and then preparations are made to start rotation.

Next, when a rotary motor (not shown) is started, the spur gear 12 meshing with the gear connected thereto rotates, and the main shaft 2 integrated therewith also rotates. Rotation of main shaft 2 is key 10,
It is transmitted to the feed shaft 32 via the keyway 11 and the tool 1
Rotate 4. The feed shaft 32 is cooled by a cooling device 34 having a coolant source, and the coolant passes through a coolant supply passage 35 in the feed shaft 32 and, as shown in FIG. In the circumferential direction, the coolant flows through a spiral groove 37 to the coolant discharge passage 36. With the coolant that has reached the tip of the pay-out shaft 32, the cutting heat generated by the tool 14 of the pay-out shaft 32 at the processing point 15 deep in the workpiece 13 during the processing shown in FIG. 3 is removed through the pay-out shaft 32. can do. At this time, the cutting fluid from the cutting fluid nozzle 4 is also used in parallel.

As an example, when the temperature of the tool raised by cutting heat is 50 degrees, the temperature of the feeding shaft 32 is 20 degrees, but by using the present invention, the temperature can be suppressed to 0 degrees.

[0017]

According to the present invention, in order to suppress the thermal expansion of the pay-out shaft due to the cutting heat generated at the time of machining, it is possible to maintain almost the required machining accuracy without performing a post-process. A pay-out spindle cooling device becomes possible.

[Brief description of the drawings]

FIG. 1 is an overall view including a spindle head of a machine tool to which an extension spindle structure according to the present invention is applied.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a diagram showing a positional relationship between a workpiece and a pay-out shaft;

FIG. 4 is an overall view including a spindle head of an extended spindle structure shown as a conventional technique.

FIG. 5 is a diagram showing a positional relationship between a workpiece and a pay-out shaft according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Main shaft 3 Feeding shaft 4 Cutting fluid nozzle 7 Ball screw 9 Hydraulic unit 10 Key 11 Key groove 32 Feeding shaft 33 Bush 34 Cooling device 35 Coolant supply passage 36 Coolant discharge passage 37 Groove

Claims (2)

[Claims] 1. A spindle cooling device having a pay-out shaft in a main shaft rotatably supported by a housing via a bearing, wherein a cooling liquid is supplied into the pay-out shaft from a cooling liquid source provided outside. A liquid supply unit, a cooling unit that circulates the coolant supplied to the payout shaft in an axial direction of the payout shaft, and a cooling unit that cools the payout shaft itself, and a coolant that circulates inside the payout shaft is provided outside the outside. And a cooling liquid recovery means for recovering the cooling liquid to a cooling liquid source. 2. The delivery shaft according to claim 1, wherein said delivery shaft has a cooling groove dug in an axial direction along a circumferential direction of a front end surface portion. Feeding shaft cooling device that was distributed.