JPH055304U - Built-in tailstock sub headstock - Google Patents

Abstract

(57) [Abstract] [Purpose] A hydraulic tailstock shaft is incorporated into the sub headstock of the facing spindle lathe so that it can be moved in and out of the retracted position and the workpiece support area, and the tailstock shaft can be clamped with a power chuck as necessary. Supports heavy cutting by supplementing rigidity. [Structure] The hole of the draw tube 13 for opening and closing the chuck, which is inserted in the second spindle 7 of the sub headstock 4 so as to be movable in the axial direction, and the hole of the second power chuck 9 have the same size, and the hydraulic pressure is applied to both holes. The tailstock shaft 15 is fitted so as to be able to move smoothly in the axial direction without a gap, the tailstock shaft is retracted during chuck work processing, and is advanced to the support area during center work to hydraulically press the center hole of the workpiece W1. It is pressed and supported so that it can exert a damper effect on the elongation of the work piece due to cutting heat. If necessary, the tailstock shaft is gripped by the second power chuck to increase the rigidity and enable heavy cutting.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a sub headstock which incorporates a tailstock shaft which can be freely taken in and out of an opposed main spindle NC lathe.

[0002]

[Prior Art]

 Conventionally, there is a technique disclosed in JP-A-64-40204 for an opposed main spindle lathe having a structure in which a center of a chuck on a sub-spindle side is gripped to support a tip of a shaft workpiece. As shown in FIGS. 3 and 4, the center unit 103, which can be moved in and out of the retracted position and the workpiece support position, is held by the collet chuck 102 at the tip of the sub spindle 101 to support the tip of the workpiece. It was done like this.

[0003]

[Problems to be solved by the device]

 In the lathe disclosed in JP-A-64-40204 described in the prior art, since the center unit is gripped by the collet chuck, there is no damper effect on the elongation of the work piece due to processing heat and the like, which causes bending. However, even if the center unit is axially movable by means of a spring and it is modified to have a built-in spring, it is difficult to achieve both sufficient thrust and the damper effect, which makes it unsuitable for heavy cutting. Remains. The present invention has been made in view of these problems of the prior art, and its purpose is to be able to follow the elongation of the work piece due to cutting heat and clamp the tailstock shaft as necessary. It is intended to provide a sub-headstock with an inner tailstock shaft that can increase rigidity.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, a sub headstock with a tailstock shaft according to the present invention is a sub headstock lathe having a sub headstock arranged so as to be movable in the Z-axis direction facing the main headstock. A power spindle is provided at the front end of the second spindle concentric with the first spindle of the main spindle stock that is rotatably supported by the spindle stock, and the fluid pressure cylinder piston member for opening and closing the power chuck is provided at the rear end thereof. A draw tube for connecting with the fluid pressure cylinder piston member is provided in the center hole of the second main shaft so as to be smoothly movable in the axial direction without a gap, and a center is provided at the tip of the inner diameter of the draw tube and the center hole of the power chuck. A detachable tailstock shaft is provided so as to be smoothly movable only in the axial direction without a gap, and fluid pressure driving means for driving the tailstock shaft in the axial direction is provided. It is obtained to perform the clamping of tailstock by the power chuck.

[0005]

[Action]

 While holding the left end of the work piece on the first power chuck of the main headstock and advancing the tailstock shaft on the sub-headstock side, the center comes into contact with the center hole on the right end of the work piece, and the tailstock shaft is stopped. The work piece is supported by the thrust of the fluid pressure drive means. In this state, the general shaft work is cut, but in the case of a heavy work heavy work, the second power chuck grips the tailstock shaft to increase the rigidity and then the cutting work. I do.

[0006]

【Example】

 An embodiment will be described with reference to FIGS. In an opposed spindle lathe, a main spindle stock 2 is fixed to the left side of a bed 1, a first spindle 3 is rotatably supported on the main spindle stock 2, and a first power chuck 10 is fitted to the tip of the first spindle. Has been done. The bed 1 has two sets of Z-axis direction guides on the upper surface, and the sub headstock 4 is movably mounted on one of the guides. It is moved and positioned via. A second spindle 7 is rotatably supported by the sub spindle stock 4 concentrically with and facing the first spindle, and the second spindle 7 is rotated by a built-in motor 8.

A second power chuck 9 is fitted to the tip of the second main shaft 7, and a rotary double cylinder having a first hydraulic cylinder 11 and a second hydraulic cylinder 12 concentrically and integrally is fixed to the rear end. Has been done. The hollow piston rod integrated with the piston of the first hydraulic cylinder 11 is connected to a plunger (not shown) in the power chuck by a draw tube 13 which is fitted into the center hole of the second main shaft 7 so as to be smoothly movable in the axial direction. By switching the pressure oil supplied from the rotary joint 14, the grip claw 9a of the power chuck 9 is opened and closed.

The inner diameter of the draw tube 13 and the hole diameter of the power chuck 9 are formed to have the same size, and the tailstock shaft 15 can be smoothly moved in the axial direction without a gap in the holes of the draw tube 13 and the power chuck 9. Relative rotation is blocked by a key (not shown) that is inserted and is provided in the hole of the power chuck. A center 16 is detachably fitted to the tip of the tailstock shaft 15, and one end of a piston rod 17 integral with the piston of the second hydraulic cylinder 12 is fixed to the rear end. Then, the tailstock shaft 15 switches the pressure oil to the second hydraulic cylinder 12 supplied from the rotary joint 14, and thereby the retracted position at the retracted end shown in FIG. 2 and the workpiece support region near the advanced end shown in FIG. The work piece is supported by the thrust of the second hydraulic cylinder 12 while being put in and out.

The grip claw 9a of the second power chuck 9 has an outer workpiece gripping portion and an inner tailstock shaft gripping portion, and the first power chuck 10 grips the center work shaft workpiece W1. When the right end is supported by the center 16 of the tailstock shaft 15 and the rigidity of the tailstock shaft is insufficient due to weight or heavy cutting, the tailstock shaft 15 is gripped by the tailstock shaft grip portion of the grip claw 9. It is designed to be clamped. On the other hand, on the other guide on the upper surface of the bed 1, a tool rest 18 is placed via a not-shown carriage so that it can be moved and positioned in the Z-axis and X-axis directions. The tool bit T is detachably attached to a plurality of tool attachment stations provided on the outer circumference of the turret 19.

Next, the operation of this embodiment will be described. When the center work shaft work W1 is cut, the sub headstock 4 is positioned at a predetermined Z-axis position based on the entire length of the work W1, and the tip of the work W1 is moved by the first power chuck 10. Gripping and supplying pressure oil to the rear chamber of the second hydraulic cylinder 12 to advance the tailstock shaft 15 via the piston rod 17, and the center 16 comes into contact with the center hole of the right end surface of the workpiece W1. The workpiece is supported by the thrust of the second hydraulic cylinder 12 in the stopped state. Then, the first main spindle 3 and the second main spindle 7 are simultaneously rotated to perform the outer diameter cutting by cutting the tool rest in the X-axis direction and cutting feed in the Z-axis direction.

If the rigidity of the tailstock shaft 15 side is insufficient because the workpiece W1 is heavy and heavy cut, the gripper claws 9a of the second power chuck 9 are closed to grip the tailstock shaft 15. , Increase the rigidity of the tailstock shaft side for heavy cutting. In this case, if there is a concern that the workpiece W1 will bend due to the elongation of the workpiece W1 due to the cutting heat, the grasping pawl 9a is opened at the cutting edge to absorb the elongation due to the damper effect of the thrust of the second hydraulic cylinder, and then again. By closing the gripping pawl 9a and continuing the cutting, it is possible to perform strong cutting without worrying about a processing accuracy defect due to bending.

Next, when cutting the workpiece W2 for chuck work, the material of the workpiece W2 is held by the first chuck 10 of the first spindle 3 to perform the primary machining on the front side, and then the tailing shaft is In the retracted state, the sub headstock 4 is moved to the Z-direction main headstock 2 side, and the processed portion of the workpiece W to be gripped by the first chuck 10 is gripped by the gripping claws 9a of the second chuck 9. The sub headstock 4 is moved to the Z-axis direction anti-main headstock side and positioned at a predetermined position, and the secondary processing of the back surface is performed.

[0013]

[Effect of the device]

 Since the present invention is configured as described above, it has the following effects. The second spindle, which has the power chuck of the sub-headstock, is provided with a tailing shaft that can be moved in and out of the retracted position and the workpiece support area by fluid pressure drive, so that chuck work and center work can be easily switched. Also, due to the damper effect on the elongation of the workpiece due to the cutting heat during machining of the center work, machining accuracy will not be lost due to bending, and if necessary, the tailstock will be gripped and clamped by the power chuck to supplement the rigidity on the tailstock side. Since it is set, heavy cutting is possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a tailstock spindle built-in type sub headstock during machining of a center work according to the present embodiment.

FIG. 2 is a partial view of a tailstock spindle built-in type sub headstock during machining of a chuck work according to the present embodiment.

FIG. 3 is a sectional view of a sub headstock in a state in which a center is retracted according to a conventional technique.

FIG. 4 is a partial view of a sub headstock in a state where a center of a conventional technique is held by a collet.

[Explanation of symbols]

 2 Main headstock 3 First spindle 4 Sub headstock 7 Second spindle 9 Second power chuck 10 First power chuck 11 First hydraulic cylinder 12 Second hydraulic cylinder 13 Draw tube 15 Tailstock shaft 16 Center

Claims (1)

[Claims for utility model registration] Claims: 1. In an opposed spindle lathe having a sub-headstock arranged so as to be movable in the Z-axis direction facing the main headstock, the sub-headstock is rotatably supported by the sub-headstock. The main spindle of the main spindle stock is provided with a second spindle concentric with the first spindle, and a power chuck is provided at the front end thereof and the power chuck opening / closing fluid pressure cylinder piston member is provided at the rear end thereof, and the power chuck and the fluid pressure cylinder piston member are provided. A tail tube having a draw tube for connecting to the second spindle is provided in the center hole of the second main shaft so that the draw tube can be smoothly moved in the axial direction without a gap, and a center is detachably attached to the inner diameter of the draw tube and the center hole of the power chuck. A fluid pressure drive means for driving the tailstock shaft in the axial direction is provided so as to be smoothly movable only in the axial direction without a gap,
A sub spindle stock with a built-in tailstock shaft, characterized in that the tailstock shaft is clamped by a power chuck as needed.