JP2737235B2 - Facing unit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a facing unit used for a machine tool for performing cutting such as boring and plane cutting.

(Prior Art) In a boring machine tool, a facing unit is mounted on a drive spindle rotatably mounted on a headstock, and a slider on which a tool for cutting a workpiece is mounted is attached to a main body of the facing unit. Is mounted so that it can slide in the radial direction. When performing boring or planar processing using such a machine tool, use a rack shaft that is slidably built in the drive spindle in the axial direction, and move this axial direction by moving the slider in the radial direction. And the blade is fed. The blade is attached to the slider via a blade holder, and in order to convert the movement of the rack shaft to the radial movement of the slider, the unit main body usually includes a gear train transmission mechanism including a rack and a pinion. Is built-in.

(Problems to be Solved by the Invention) However, as described above, when the blade holder is sent via the slider in a direction perpendicular to the rotation center of the drive spindle, that is, in the radial direction, the movement of the slider and the blade holder is performed. Accordingly, the center of gravity of the slider and the blade holder also moves, and the center of gravity of the slider and the blade holder is added to the position of the center of gravity when the center of rotation of the drive shaft shifts from one region to the other region. A phenomenon occurs in which the direction of action of the centrifugal force is reversed. Due to this phenomenon, the direction of the load applied to the gear train transmission mechanism having the meshing portion between the rack and the pinion is switched in the opposite direction during cutting.

Therefore, the slider, that is, the blade holder, suddenly shifts to the opposite side due to the backlash in the meshing portion between the rack and the pinion.
At this time, there is a problem that a change occurs in the feed operation of the blade holder, the cutting state is suddenly changed, and the uniform state of the cutting surface is not maintained, and there is a possibility that a streak or a scratch is generated on the cutting surface of the work. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a facing unit capable of constantly maintaining a feed operation of a blade holder and forming a uniform cut surface.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a unit main body fixed to a hollow driving main shaft, comprising a slider movably in a radial direction with respect to a rotation center axis of the driving main shaft. A gear train transmission mechanism that mounts, attaches a cutting tool for cutting a workpiece to the slider, and converts a sliding motion slidably mounted in the drive spindle into a radial movement of the slider. The slider is incorporated in the unit main body, and the slider is configured such that the center of gravity of the slider to which the blade is attached can move from a region on one side of the rotation center of the drive spindle to a region on the opposite side. In a facing unit mounted on a main body, a spring force is applied between the slider and the unit main body in a direction parallel to a rotation center of the drive main shaft. A facing unit, characterized in that a suppressing spring member centrifugal force applied to the center of gravity of the slider by the braking force based on the friction force between the slider abuts against the end surface of the slider while.

(Function) In the present invention having such a configuration, a braking force based on a frictional force is applied to the slider supporting the blade by a spring member that applies a spring force in a direction parallel to the rotation center of the driving main shaft. By moving the slider to move the blade, the center of gravity of the slider including the blade moves, and even if the load direction applied to the gear train transmission mechanism is reversed during cutting, the Even if there is a backlash, the moving speed of the blade or holder does not suddenly change. Therefore, the feed operation of the blade is made constant in the entire feed stroke.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 1 to 3 show a facing unit according to an embodiment of the present invention. The facing unit 1 of this embodiment is a hollow drive spindle that is rotatably mounted on a headstock 2 of a machine tool. 3 attached. A bearing 4 is incorporated between the headstock 2 and the drive spindle 3. A unit main body 5 is fixed to the tip of the drive main shaft 3, and a slider 6 is mounted on the front end surface of the unit main body 5 movably in the radial direction with respect to the rotation center axis of the drive main shaft 3. I have. A blade 8 is attached to the slider 6 via a blade holder 7.

In order to guide the slider 6 to which the blade holder 7 is attached in the radial direction, a second main body is provided.
As shown in the figure, a sliding groove 9 having a T-shape as a whole is formed. In order to drive the slider 6 along the sliding groove 9, a rack shaft 10 is mounted in the hollow driving main shaft 3 so as to be reciprocally movable in the axial direction. This rack tooth 11 is formed 11
A pinion 12 is rotatably mounted on the unit body 5, and a pinion (not shown) directly connected to the pinion 12 is formed to mesh with the rack 13.
The rack shaft 10, the pinion 12, and the like constitute a gear train transmission mechanism 14 for driving the slider 6.

Further, the sliding groove 9 provided in the unit main body 5 is provided.
On the bottom surface of the device, two mounting holes 15 opening toward the slider 6 are formed. In the mounting holes 15, a disc spring 16 as a spring member is mounted. Belleville spring 16
Is mounted so as to protrude from the mounting hole 15, and the protruding portion is pressed against the bottom surface of the slider 6. In addition, the said mounting hole 15 is formed in the slider 6,
The disc spring 16 may be stored in this.

The center axis of rotation of the drive spindle 3 is indicated by O in FIG.
Assuming that the center of gravity of the slider 6 including the blade holder 7 at the illustrated position is at the position indicated by the symbol G, when the drive main shaft 3 is rotated under this state,
As indicated by the arrow S, a centrifugal force is applied to the slider 6 in a direction to return the blade 8. In this state, when the slider 6 further moves below the position shown in FIG. 1 and the position of the center of gravity G moves past the central axis O, the centrifugal force reverses to the above and the blade 8 Acts in the direction toward.

Since the disc spring 16 is in contact with the bottom surface of the slider 6, a braking force is applied to the slider 6 based on a frictional force with the slider 6, whereby the slider 6 including the blade holder 7 is moved. Centrifugal force applied to the center of gravity G is suppressed. Thus, the slider 6 and the blade holder 7 are not moved in a direction perpendicular to the driving main shaft 3 by the centrifugal force.

When boring or surface machining is performed by such an embodiment, the entire facing unit 1 is rotated at a predetermined speed integrally with the facing drive unit 3 by the rotational driving force of the drive spindle 3, and the slider 6 and the blade holder 7 are moved together. The gear train transmission mechanism 14 integrally moves in the radial direction of the drive main shaft 3, that is, in the direction perpendicular to the center axis. Thus, the cutting operation is performed while the blade 8 is being fed at a predetermined speed.

In this case, the centrifugal force applied to the center of gravity G of the slider 6 and the blade holder 7 is canceled out by the braking force based on the frictional force between the disc spring 16 and the slider 6 pressed against the slider 6, and the slider 6 and the blade holder 7 are offset. Is prevented from moving in the direction perpendicular to the drive spindle 3 by the centrifugal force. Therefore, even when the centrifugal force acts in the opposite direction when the center of gravity G of the blade holder 7 and the slider 6 is shifted from one area of the main shaft 3 to the opposite area, the rack 11 and the pinion Even if the load direction to the gear train transmission mechanism 14 meshed with 13 etc. is reversed during cutting, it is always constant without being affected by backlash at the meshing part with the rack 11 and pinion 13 Tool 8 with high accuracy while maintaining the speed of
Will be sent.

(Effect of the Invention) As described above, according to the present invention, the centrifugal force applied to the slider on which the blade is mounted is changed in a direction parallel to the rotation of the drive spindle so that the blade feed operation is always constant. A spring member for urging a spring force along the slider is brought into contact with the end face of the slider and is suppressed by a braking force based on a frictional force between the slider and the slider. Therefore, the center of gravity of the slider 6 to which the blade is attached is mounted. When the direction of the centrifugal force is reversed when the gear is shifted from one side of the rotation center of the drive main shaft to the other side, the gear train transmission mechanism for driving the slider Even if the load direction is reversed in the middle of cutting, the blade will operate reliably with a constant stroke without being affected by backlash in the gear train transmission mechanism, and it will be uniform to the workpiece A highly accurate cut surface can be formed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a facing unit according to an embodiment of the present invention, FIG. 2 is a view taken along the line II-II in FIG. 1, and FIG. 3 is a left side view of FIG. . 1 ... facing unit, 2 ... headstock,
3 ... drive spindle, 5 ... unit body, 6 ... slider, 7 ... blade holder, 8 ... blade, 10 ... rack shaft, 14 ... gear train transmission mechanism, 16 ... disc spring (spring member) ).

Claims (1)

(57) [Claims] A slider is mounted on a unit body fixed to a hollow drive spindle so as to be movable in a radial direction with respect to a rotation center axis of the drive spindle, and a blade for cutting a workpiece is attached to the slider. A rack shaft slidably mounted in the drive main shaft in the axial direction and a gear train transmission mechanism for converting a sliding motion into a radial movement of the slider, wherein the gear train transmission mechanism is incorporated in the unit main body; A facing unit mounted on the unit body such that the center of gravity of the slider to which the blade is attached can be freely shifted from a region on one side of the center of rotation of the drive spindle to a region on the opposite side; Between the unit and the unit body, while applying a spring force along a direction parallel to the rotation center of the drive main shaft and abutting against the end face of the slider. A facing member provided with a spring member for suppressing a centrifugal force applied to the center of gravity of the slider by a braking force based on a frictional force with the slider.