JP2009107037A - Spindle structure of lathe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixture structure capable of enhancing productivity by increasing the rotational speed of a spindle and improving the working accuracy of cylindrical workpiece. <P>SOLUTION: This spindle structure of a lathe having a fixture unit 20 comprises a cylinder mechanism M which is disposed on the same axis as the spindle 14 of the lathe and which unclamps the fixture by a pressure fluid and unclamps the workpiece by a spring force, a fluid supply means P for supplying the pressure fluid to the cylinder mechanism M through the inside of the spindle of the lathe, and a fixture mechanism N for clamping the workpiece W. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a main spindle structure of a lathe provided with a Yatoi unit.

FIG. 5 is a cross-sectional view showing a spindle structure of a conventional lathe equipped with a Yatoi unit, and FIG. 6 is an enlarged view of the spindle tip.
As shown in FIGS. 5 and 6, the spindle 1 of the NC lathe is rotatably held inside the spindle stock via a plurality of bearings 2. In the center of the main shaft 1, there is a work clamp draw bar 6 for holding a plug 5 for clamping the work 3 with a yatoe 4 at its tip, and a rear end of the work clamp draw bar 6. And a work clamping cylinder 7 which is connected to the cylinder piston 8 and advances and retracts in the axial direction. Further, a chuck clamp draw bar 9 is provided in the main shaft 1 so as to surround the work clamp draw bar 6 and is provided in a tube concentric with the work clamp draw bar 6. And a chuck clamp cylinder 10 which is connected to the cylinder piston 11 at the rear end of the chuck clamp draw bar 9 and advances and retracts in the axial direction.

  Accordingly, in order to unclamp, the cylinder piston 8 of the work clamping cylinder 7 is operated, and the work clamping draw bar 6 is advanced in the right direction in the drawing. Then, the plug 5 moves forward in the right direction of the drawing, and the opening yatoy 4 remains in its original position, so that the opening yatoy 4 is reduced in diameter by elasticity. In this state, the workpiece 3 is extracted in the right direction of the drawing. In this state, a new work 3 is fitted on the opening yatoy 4 whose diameter is reduced from the right side of the drawing. The cylinder piston 8 of the cylinder 7 is actuated to retract the work clamp draw bar 6 in the left direction of the drawing. Then, the stopper 5 moves backward in the left direction of the drawing, and the opening yatoy 4 remains at the original position, so that the opening yatoi 4 is expanded in diameter by the stopper 5. As a result, the outer periphery of the large-diameter cylindrical portion 4 of the opening yatoy 4 is pressed against the inner peripheral surface of the workpiece 3, the workpiece 3 is clamped to the opening yatoy 4, and the opening yatoy 4 is automatically detachable from the front end portion of the spindle 1. Is configured to hold.

JP 2001-170802 (FIGS. 1 and 2)

However, in the conventional Yatoi unit, in order to attach and detach a cylindrical workpiece to and from the tip of the main shaft, the draw bar 6 is passed through the through hole of the main shaft 1, and the draw bar 6 is supported in the main shaft, and always in the axial direction by the draw bar 6. Always had to be pulled to.
For this reason, there is a problem that the draw bar 6 is bent in the radial direction during high-speed rotation to generate vibrations, causing chatter marks on the workpiece, affecting the machining accuracy and not improving the quality.
SUMMARY OF THE INVENTION In order to solve these problems, it is an object of the present invention to provide a Yatoi unit that has a high machining accuracy for a cylindrical workpiece and that is capable of high-speed rotation of a spindle to improve productivity. To do.

A main spindle structure of a lathe according to the first aspect of the present invention, wherein a Yatoi unit is attached to the front end of the main spindle and grips a cylindrical workpiece W from the inside, and penetrates from the rear end to the front end of the main spindle. A lathe spindle structure comprising a drilled hollow hole and a fluid supply device for supplying compressed air from the rear end to the hollow hole,
The Yatoi unit includes a disk-shaped flange fixed to the tip of the main shaft, a cylindrical cylinder fixed to the flange, a base fixed to the tip of the cylinder and having a through hole in the center; A piston having a boss portion that is slidably supported on an inner peripheral surface of the cylinder and is protruded by being inserted through a through hole of the base, and is sandwiched between the base and the piston, and the piston is attached to the main shaft Fixed to the boss, a spring that is biased to the side, a gripping portion that is fixed to the base and is provided on the outer peripheral surface to grip the inner peripheral surface of the workpiece, a tapered hole whose tip end is enlarged in diameter, and And a taper guide that engages with the taper hole and expands the diameter of the grip portion.
It should be noted that the best mode used for the fluid supply apparatus can use air or hydraulic oil as the fluid, and operates the Yatoi unit using pneumatic pressure or hydraulic pressure.

  The invention according to claim 2 is the main spindle structure of the lathe according to claim 1, wherein the fluid supply device is provided with a pipe for transferring compressed air so as to contact and separate from a rear end opening of the main spindle. And a drive means for providing a nozzle provided at the tip of the tube and supporting the nozzle so as to advance and retreat.

According to the main spindle structure of the lathe of the present invention, the Yatoi unit can be operated by pneumatic pressure without attaching a draw bar inside the main spindle, as in the past, so that machining accuracy can be reduced while suppressing vibration associated with high-speed rotation of the main spindle. And productivity can be improved.
Further, the Yatoi unit of the present invention can securely clamp the cylindrical workpiece and process the entire circumferential surface of the cylindrical workpiece.
Also, compared to the case where the Yatoi is clamped and unclamped by pneumatic or hydraulic cylinders, it is configured to clamp using a spring on one side as in the present invention. Even when electricity is not supplied to the lathe and the machine is stopped, the workpiece clamping can be continuously maintained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a longitudinal section of a main spindle of a lathe equipped with a Yatoi unit according to the present invention.
As shown in FIG. 1, the lathe headstock 10 is fixed on a bed 11 (not shown), and the main spindle 14 is a long hollow member with a hollow hole 14 c extending in the axial direction. A bearing 10 is supported by a housing 10c and 10d provided at 10a so as to be rotatable and horizontally supported by a bearing 12. The outer periphery of the main shaft 14 is directly connected by a built-in motor 15 constituted by a rotor 15a mounted on the outer peripheral side of the main shaft 14 and a stator 15b fitted to the inner peripheral surface of a cooling sleeve 10b mounted on the main body 10a. It can be rotated. Further, an adapter 14 a is screwed onto the main shaft 14 at the rear end portion of the main shaft 14.

(Yatoi unit)
The Yatoi unit is arranged on the same axis as the lathe spindle 14, the cylinder mechanism M that unclamps the workpiece with the pressure fluid of the yatoi and clamps the workpiece with the spring force, and the cylinder mechanism M that passes through the lathe spindle. It comprises fluid supply means P for supplying pressure fluid to the side and a Yatoi mechanism N for clamping the workpiece W.

In addition, since this Yatoi unit clamps the workpiece | work W from an inner side, generally it is used for the light cutting or light grinding which processes the whole peripheral surface of the cylindrical member made from AL.
In the present embodiment, air is used as the fluid used in the fluid supply device P of the Yato unit 20.

The parts and mechanisms constituting the Yatoi unit 20 will be described in detail with reference to exploded views shown in FIGS. 2 (a) and 2 (b), sectional views showing operating states, and FIGS. 3 and 4. FIG.
(Cylinder mechanism)
The cylinder mechanism M includes a flange 21 fixed to the end face of the main shaft 14 with a bolt 21f, a cylinder 22, a piston 25 having a boss portion 25a fixed with a bolt 25l, and a base 29 fastened to the cylinder 22.
That is, the flange 21 forms one end of the cylinder 22, is formed in a disk shape, and is fixed to the main shaft 14 via the bolt 21f. The side end face of the main shaft 14 is formed with a recess not shown for centering the flange 21 and the main shaft 14, and the recess not shown and the outer peripheral portion of the end face of the main shaft 14 are fitted with each other by a bolt 21f. It is fixed.

The cylinder 22 is formed in a cylindrical shape, and is fixed to the base 29 with bolts 17. As shown in FIGS. 2A and 2B, the piston 25 has eight blind holes 25j for positioning the spring 26, and eight end holes 29j are opposed to the end surface of the base 29, respectively. The spring 26 is provided between the base 29 and the piston 25 by inserting upper and lower ends into the blind hole 25j and the blind hole 29j, and is fastened and fixed by the bolt 16.
In addition, an O-ring groove 25c is formed on the outer periphery of the piston 25, an O-ring 25b is mounted on the O-ring groove 25c, an O-ring groove is omitted on the main shaft 14, and an O-ring 14b is mounted and compressed Air confidentiality can be maintained.

The inner peripheral surface 22a of the cylinder 22 is smoothly finished so that the O-ring 25b of the piston 25 can slide. The cylinder 22 may be configured as a part integrated with the flange 21 by cutting.
The base 29 is fixed to the end surface of the flange 21 with the bolt 16 via the cylinder 22.
Therefore, when the compressed air is stopped, when the workpiece W is clamped, the compressed air on the piston 25 and the hollow hole 14c side is released to the atmosphere. At this time, the piston 25 can move in the direction of the tip opposite to the main shaft 14 by the spring force of the spring 26.

(Fluid supply device)
As shown in FIG. 1, the fluid supply device P passes through the hollow hole 14c of the main shaft 14 from the rear end portion of the main shaft 14, supplies compressed air to the space formed by the cylinder 22 and the piston 25, and is stronger than the spring force. It is a device that moves the piston 25 with the applied pressure.
An attachment stay 38 is fixed to the main body 10a at the rear part of the main shaft 14, an air cylinder 35 as a driving means is supported at the tip thereof, and a nozzle 34 with a cushion 37 is provided at the tip of the piston 35a. The nozzle 34 with the cushion 37 can be moved to and away from the adapter 14a on the rear end surface of the main shaft 14 by the operation of the air cylinder 35.
The material of the cushion 37 is preferably an elastic material such as oil-resistant rubber.

(Yatoi mechanism)
The base 29 is formed in a disk shape and forms the other end of the cylinder 22. In the center of the base 29, a through-hole 29a in which the boss 25a of the piston 25 is slidable is provided, and a recess 29c for centering with the yatoy 30 is formed. The flange 30 f of the yatoy 30 is fitted and fixed by the bolt 18.
The yatoy 30 is a kind of chuck that directly presses the inner peripheral surface of the workpiece W and holds the workpiece W, and is also called an open yatoy. A flange 30 f is formed at the rear end portion of the yatoy 30, and this flange 30 f is fitted into a recess 29 c provided on the end surface of the base 29 to determine the position, and is fixed by a bolt 18. The grip portion 30d of the yatoy 30 is easily deformed by a relief with a narrowed outer diameter until the grip portion 30d provided at the tip portion.
Further, a hole 30g fitted with the boss 25a of the piston 25 is provided at the center, and a tapered hole 30c is formed at the tip.
As shown in FIG. 2, the taper guide 33 has a function of causing the holding portion 30 d formed with the slit groove 30 e of the yatoy 30 to be elastically deformed and expanding the diameter of the holding portion 30 d. Note that a rubber ring may be attached as an elastic body on the outside of the grip portion 30d of the yatoy 30 to improve the frictional force.

A taper angle fine adjustment mechanism C is provided so that the taper angle of the taper guide 33 can be finely adjusted. In this mechanism C, a hole 30f is provided at the center of the taper guide 33, a female screw 33e is threaded into the hole 30f, and a small screw 33f is screwed into this screw. Further, a female screw 25f is formed in the boss portion 25a, and a screw 33g of the taper guide 33 is screwed into the female screw 25f.
Therefore, when the small screw 33d is rotated with a screwdriver tool, the tapered surface of the head of the small screw 33f comes into contact with the tapered hole 30c, and the diameter of the gripping portion 30d is increased by adjusting the tapered portion of the taper guide 33. It can be adjusted.

(Operation of Yatoi unit)
Next, the attaching / detaching operation of the cylindrical workpiece W by the Yatoi unit 20 will be described in detail below.
As shown in FIG. 3A, the work W is mounted on the main shaft 14 by switching the direction switching valve 39 shown in FIG. 1, and as shown in FIG. It is in close contact with the end surface of the adapter 14a provided at the end, and compressed air is supplied into the hollow hole 14c of the main shaft 14 from the rear end side of the main shaft 14, and the piston acts against the spring force of the spring 26 by the pressure of this compressed air. Advance 25. Then, the piston 25 advances rightward, following the movement of the piston 25, the engagement between the taper hole 30c and the taper guide 33 is released, the grip portion 30d is reduced in diameter by elastic force, and the workpiece W can be mounted. Put it in a state.

As shown in FIG. 3 (b), the work W is mounted on the spindle 14, after the work W is mounted on the gripping portion 30d, the direction switching valve 39 is switched to separate the nozzle 34 from the end of the adapter 14a. The supply is shut off, and the compressed air in the hollow hole 14c in the main shaft 14 is released to the atmosphere. As a result, the piston 25 moves left due to the spring force of the spring 26. Following the movement of the piston 25, the taper hole 30c and the taper guide 33 are engaged with each other at the taper surface, the gripping portion 30d expands in the radial direction, and the workpiece W is clamped from the inside.
Accordingly, the workpiece W is clamped by the grip portion 30d at the tip of the yatoe 30. When the processing of the outer peripheral surface of the workpiece W is completed, the workpiece W is removed.
After the workpiece W is processed, the removal is performed in the state shown in FIG. 1 by switching the direction switching valve 39 and, as shown in FIG. 3B, through the cushion 37 provided in the nozzle 34, the end of the main shaft 14 The compressed air is supplied into the hollow hole 14c of the main shaft 14, and the piston 25 is advanced against the spring 26 by the pressure of the compressed air. Then, when the piston 25 moves to the right, the taper guide 30 moves to the right via the spring 26, and the engagement between the taper hole 30c and the taper guide 33 is released following the movement of the piston 25. The portion 30d is reduced in diameter by the elastic force, and the workpiece W is unramped. In this state, the workpiece W is extracted rightward in the drawing, and all operations are completed.

The configuration and operation of one embodiment of the present invention have been described above, but the present invention is not limited to this embodiment.
For example, in the above embodiment, the compressed air supply means that closes the yatoy and unruns the workpiece W may be provided with an air pressure or hydraulic circuit that applies air pressure or oil pressure.
Moreover, in the said embodiment, although compressed air supplied compressed air in the hollow hole 14c of the main axis | shaft 14 from the rear part of the main axis | shaft 14, as another aspect, the air supply means P is a cylinder part from a side surface, It is also possible to connect a pneumatic circuit or a hydraulic circuit for energizing pneumatic pressure or hydraulic pressure.
Furthermore, the piston 25 provided in the cylinder mechanism M may be passed through a hollow hole from the front side surface of the main shaft 14, supplied with compressed air from the rear portion of the main shaft 14, and operated by its pressure.
In addition to this, the above-described yatoy can be applied to other chucks such as a closing yatoy or a sandwich clamp type chuck. The closing yatoy is usually called a collet chuck, and is a chuck for attaching a tool such as a drill or a reamer.

It is sectional drawing which shows the spindle structure of the lathe which mounted | wore with the Yatoi unit which concerns on this invention. (A) is an exploded view showing the Yato unit according to the present invention. (B) represents the AA arrow line view of Fig.2 (a). BRIEF DESCRIPTION OF THE DRAWINGS It is an expanded sectional view which shows the main-axis front-end | tip part of the lathe which can mount | wear with the Yatoi unit of this invention, (a) shows the clamped state of a Yatoi unit. (B) also shows the unclamped state of the Yatoi unit. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged cross-sectional view showing a main spindle structure rear end portion of a lathe capable of being mounted with a Yatoi unit of the present invention, and FIG. (B) shows the connection state of the air cylinder and the pneumatic circuit on the spindle side. It is sectional drawing showing FIG. 1 shown in patent document 1. FIG. FIG. 3 is an enlarged view showing FIG. 2 shown in Patent Document 1.

Explanation of symbols

M Cylinder mechanism N Yatoi mechanism P Fluid supply means 10 Main shaft base 10a Main body 14 Main shaft 14c Hollow hole 15 Built-in motor 20 Yatoi unit 21 Flange 22 Cylinder 22a Inner peripheral surface 25 Piston 25a Boss portion 26 Spring 29 Base 30 Yato 30c Tapered hole 30d Grip part 30f Flange 33 Taper guide 35 Air cylinder drive means

Claims (2)

A Yatoi unit that is attached to the front end of the main shaft and grips the cylindrical workpiece W from the inside, a hollow hole that penetrates from the rear end portion to the front end portion of the main shaft, and the rear end in the hollow hole A lathe main spindle structure comprising a fluid supply device for supplying compressed air from a section,
The Yatoi unit is
A disc-shaped flange fixed to the tip of the spindle;
A cylindrical cylinder fixed to the flange;
A base fixed to the tip of the cylinder and having a through hole in the center;
A piston having a boss portion that is slidably supported on the inner peripheral surface of the cylinder and is protruded by being inserted into a through hole of the base;
A spring sandwiched between the base and the piston and biasing the piston toward the main shaft;
A yatoy fixed to the base and having a gripping portion provided on the outer peripheral surface for gripping the inner peripheral surface of the workpiece, and a tapered hole having an enlarged diameter on the tip side;
A taper guide fixed to the boss portion and engaged with the taper hole to expand the grip portion;
A lathe spindle structure characterized by comprising The fluid supply device includes:
A pipe for transferring compressed air so as to be in contact with and away from the rear end opening of the main shaft, and a nozzle provided at the tip of the pipe;
Driving means for supporting the nozzle so as to be movable forward and backward;
The main spindle structure of a lathe according to claim 1, comprising:

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