JPH07164207A - Guide bush device of spindle traveling lathe - Google Patents

Abstract

PURPOSE:To provide a guide bush device which can support a rod material so as to rotate through a fixed micro clearance all the time even if any dimensional error exists in the outside diameter of the rod material. CONSTITUTION:A guide bush adjusting gear 22 is thread-engaged with the rear end of a guide bush 18 for supporting a rod material 1 so as to rotate, and the guide bush adjusting gear 22 is rotated by a servo motor 26, thereby moving the guide bush 18 in the axial direction to a guide bush sleeve 17 which holds the guide bush to increase or decrease the inside diameter of the guide bush. At the time of inserting the rod material 1 in the guide bush 18, the servo motor reduces the diameter of the guide bush 18 once to make its inner surface an original point by pressing it against the outer surface of the rod material. The servo motor 26 is controlled by a controller so as to change the inside diameter of the guide bush 18 to such a value that increases by a required amount from the original point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guide bush device for supporting a bar member held on a main shaft in the vicinity of a cutting position in a main shaft moving type lathe.

[0002]

2. Description of the Related Art Conventionally, in a main spindle moving type lathe, a guide bush is arranged in front of the main spindle so as to be positioned on the same axis as the main spindle, and the rod held by the main spindle is supported near the cutting position. It is configured to prevent flexural deformation of the bar during processing. Here, the guide bush is usually non-rotatably provided for a small-diameter material (fixed guide bush), and holds the bar material held by the main shaft rotatably and axially movably. . Therefore, the inner diameter of the guide bush is set to be slightly larger than the outer diameter of the bar. Generally, a bar processed by a spindle moving type lathe is a drawn bar, so that the dimensional accuracy is good. For example, for a bar having an outer diameter of 10 mm, the tolerance is H6 (+0 mm, −
0.009 mm) ~ H7 (+0 mm, -0.015 m
m) and the difference in outer diameter between the rods is about 15 μ at maximum. The inner diameter of the guide bush is about 3 to 5μ larger than that of the maximum diameter of the rods with the tolerance so that it can be rotatably held regardless of which rod comes in. The clearance is set to about 3 to 5 μ at the minimum.

[0003]

However, in such a conventional structure, when the outer diameter of the bar is the upper limit within the predetermined tolerance range, the clearance between the guide bush and the bar is 3 to. Although it is as small as 5 μ, when the lower limit is within the predetermined tolerance range, the clearance becomes as large as 18 to 20 μ, and there is a problem that the machining accuracy is affected when ultra-high-precision finishing is performed.

Therefore, in order to perform ultra-high precision processing, it is desirable that the clearance between the guide bush and the bar is small, for example, about 3 to 5 .mu. If there is a dimensional difference of about 15 μm and the guide bush inner diameter is constant, such a request cannot be achieved. Conventionally, in such a case, the clearance is manually adjusted every time the bar material changes, which is extremely troublesome.

The present invention has been made in view of the above problems, and always automatically sets the clearance between the bar and the guide bush to a minute constant value even if the bar has a dimensional difference. It is an object of the present invention to provide a guide bush device for a spindle moving type lathe that enables the above.

[0006]

DISCLOSURE OF THE INVENTION The present invention, which has been made to achieve the above-mentioned object, is arranged in front of a main shaft so as not to rotate on the same axis as the main shaft, and rotatably supports a bar member held by the main shaft. A guide bush, a guide bush inner diameter adjusting mechanism that adjusts the inner diameter of the guide bush, a servo motor that drives the guide bush inner diameter adjusting mechanism, and a controller for the servo motor. When the rod is inserted into the guide bush, the inner diameter of the guide bush is reduced to tighten the rod, and then the inner diameter of the guide bush is enlarged by a predetermined amount from the inner diameter when the rod is tightened. A guide bush device for a spindle moving type lathe is characterized in that it has a function of controlling the servo motor so that the value becomes a value.

[0007]

In the guide bush device of the present invention having the above structure,
When a new rod is held on the spindle and the rod is inserted into the guide bush, the controller drives the servo motor to drive the guide bush inner diameter adjustment mechanism to reduce the inner diameter of the guide bush. Tighten the bar once. Next, the control device controls the servo motor again to change the inner diameter of the guide bush and set the inner diameter when the rod is tightened as the origin, and only a predetermined small fixed amount (for example, 2 to 2) from the origin. 3 μ), and set to an enlarged value. Thus, the guide bush can support any of the rods with a constant small clearance even if the rods inserted into the guide bush have different outer diameters. In addition, after the guide bush tightens the rod, the procedure of setting the guide bush to a value in which the inner diameter is enlarged by a certain amount with respect to the rod may simply enlarge the inner diameter of the guide bush by a certain amount. By temporarily enlarging the guide bush inner diameter to a value larger than the predetermined amount and then reducing it, a method of obtaining a desired inner diameter can be obtained, which can eliminate the influence of the backlash of the guide bush inner diameter adjusting mechanism. preferable.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention shown in the drawings will be described below. FIG. 1 is a schematic sectional view showing a spindle moving type lathe equipped with a guide bush device according to an embodiment of the present invention, FIG. 2 is an enlarged schematic sectional view showing an essential part of the guide bush device, and FIG. It is a front view. 1 to 3, 1 is a bar to be processed, 2 is a spindle device that holds the bar, and 3 is a bed that holds the spindle device 2. The spindle device 2 includes a spindle stock 5 and a spindle 6 which is rotatably held by the spindle stock 5 and has a chuck mechanism for gripping the rod 1.
And a built-in motor (not shown) for rotationally driving the spindle 6, and the headstock 5 is held so as to be movable in the spindle axis direction with respect to the bed 3. Reference numeral 8 denotes a headstock moving device that reciprocates the headstock 5 in the axial direction of the main shaft 6, and includes a screw shaft 9 provided rotatably in the bed 1 in parallel with the main shaft 6, and attached to the headstock 5. A nut 10 that meshes with the shaft 9 and a Z-axis servomotor 11 connected to the screw shaft 9 are provided. Thus, the headstock 5 and the spindle 6 can be moved forward and backward in the axial direction by the forward rotation and the reverse rotation of the Z-axis servomotor 11, and therefore,
The bar 1 held by the main shaft 6 can be moved forward and backward.

Reference numeral 13 is a guide bush device, which is attached to a support base 14 attached to the bed 3 and has a main shaft 6
A guide bush holder 15 having a through hole having the same axis as the axis of the above, a sleeve chuck 16 having a hollow structure inserted in the through hole of the guide bush holder 15 so as to be movable in the axial direction, and the inside of the sleeve chuck 16. A hollow guide bush sleeve 17 inserted axially movably into the guide bush sleeve 17 and a guide bush 18 axially movably inserted into the guide bush sleeve 17.
And so on. The guide bush 18 includes a support surface 18a that rotatably supports the bar 1 on its inner surface.
The sleeve chuck 16, the guide bush sleeve 17, and the guide bush 18 are prevented from rotating by appropriate means, and thus cannot rotate.

The guide bush holder 15 has a tapered surface 15a at the tip of the through hole, while the sleeve chuck 16 inserted therein has a tapered surface 16a on the outer surface which is substantially the same slope as the tapered surface 15a. . A slit 16b is formed at the tip of the sleeve chuck 16 so that the sleeve chuck 16 can be easily elastically deformed inward and outward, and the sleeve chuck 1 is also provided.
When the outer periphery of 6 is not constrained by the guide bush holder 15, the dimensions are determined so that the elastic force of the guide bush holder deforms outward in the radial direction from the illustrated state. Further, an outer screw 16c is formed at the rear end of the sleeve chuck 16,
A nut 20 is attached to the outer screw 16c. Thus, by screwing the nut 20 and pulling the sleeve chuck 16 to the right in FIG. 2 (toward the main shaft 6), the sleeve chuck 16 is deformed inward and the guide bush sleeve 17 is fixed so as not to move. On the contrary, the guide bush sleeve 17 can be moved by loosening the nut 20.

The guide bush sleeve 17 also has a tapered surface 17a on the inner surface of the tip thereof, while the guide bush 18 inserted therein has a tapered surface 18b on the outer surface thereof, which is inclined almost the same as the tapered surface 17a. The guide bush 18 is also attached to the tip of the guide bush 18.
Is formed with a slit 18c so that it can be easily elastically deformed inward and outward, and when the outer periphery of the guide bush 18 is not constrained by the guide bush sleeve 17, the elastic force of the slit 18c causes the outer side in the radial direction more than the illustrated state. It is dimensioned to transform into Thus, by pulling the guide bush 18 to the right in FIG. 2 (toward the main shaft 6), the guide bush 18 is deformed inward and the inner diameter of the support surface 18a can be reduced, and the guide bush 18 can be moved in the opposite direction. Thereby, the inner diameter of the support surface 18a can be increased.

In order to move the guide bush 18 in the axial direction with respect to the guide bush sleeve 17, an outer screw 18d is formed at the rear end portion of the guide bush 18, and the outer screw 18d is used to adjust the guide bush. The internal screw 22a formed on the gear 22 is meshed. Further, a thrust bearing 23 and a spacer 24 are arranged between the guide bush adjusting gear 22 and the rear end of the guide bush sleeve 17 to keep the positional relationship between the thrust bearing 23 and the spacer 24 constant in the axial direction. Thus, by rotating the guide bush adjusting gear 22 in one direction, the guide bush 18 can be pulled rightward in FIG. 2 to reduce the inner diameter of the guide bush 18, and by rotating in the opposite direction, the guide bush 18 The inner diameter can be enlarged. These tapered surfaces 17a and 18b, the guide bush adjusting gear 22 and the like constitute a guide bush inner diameter adjusting mechanism for adjusting the inner diameter of the guide bush.

Reference numeral 26 is a servomotor for rotationally driving the guide bush adjusting gear 22, 27 is a drive gear attached to the shaft of the servomotor 26, and 28 is a drive gear 2.
It is an intermediate gear that transmits the rotation of 6 to the guide bush adjusting gear 22. A control device (not shown) is connected to the servo motor 26. The control device used here has a function of automatically setting the inner diameter of the guide bush 18 by the procedure described later. In the present specification, the guide bush 18 is included in the rotation of the guide bush adjusting gear 22 and the servo motor 26 that drives the guide bush adjusting gear 22.
The rotation in the direction of decreasing the inner diameter of is the normal rotation, and the opposite is the reverse rotation.

Reference numeral 31 is a tool stand, and 32 is a blade held by the tool stand. The tool base 31 is configured to move in a vertical direction and a horizontal direction in a plane perpendicular to the spindle axis, so that the bar 1 supported by the guide bush 18 can be moved in the vicinity of the guide bush 18. It is possible to perform processing such as cutting by one of 32.

Next, the operation of the guide bush device having the above structure will be described with reference to the operation flowchart shown in FIG. In the standby state in which the bar 1 is not inserted into the guide bush 18, the guide bush 18 is in a diameter-expanded state. When a bar material feeder (not shown) inserts a new bar material 1 into the main shaft 6 from the rear of the main shaft 6, the main shaft 6 clamps and fixes the bar material 1, and holds the bar material 1 to move forward. Then
The tip of the rod 1 is inserted into the guide bush 18.

When the bar 1 is inserted into the guide bush 18 and stopped at a predetermined position, the servo motor 26 of the guide bush device 13 rotates in the forward direction, and the guide bush adjusting gear 2
2 is rotated in the forward direction to reduce the inner diameter of the guide bush 18 and pressed against the bar 1 (tighten the bar 1). When the tightening force of the guide bush 18 with respect to the bar 1 reaches a preset value, that is, when the tightening torque of the servo motor 26 reaches a set value, the torque from the current value to the servo motor 26 is set to the set value. When the servo motor 26 is stopped, the servo motor 26 is stopped and the position is stored and set as the origin.

Next, the servo motor 26 is rotated at a predetermined rotation speed n.
_The bar 1 is opened by rotating the guide bush 18 in the reverse direction by 1 and expanding the inner diameter of the guide bush 18 by a predetermined amount. Here, the enlargement amount of the inner diameter of the guide bush 18 is set to be larger than the desired clearance between the bar 1 and the guide bush 18, and is about 50 μ, for example. Next, the servo motor 26 is rotated forward by a predetermined rotation speed n ₂ (<n ₁ ) to reduce the inner diameter of the guide bush 18 by a predetermined amount. Here, the reduction amount of the inner diameter of the guide bush 18 is set so that the clearance between the guide bush 18 and the bar 1 has a desired value, for example, 2 μ or 3 μ. Thus, the clearance between the guide bush 18 and the bar 1 is always a desired value at the time when the servomotor 26 is positively rotated by the predetermined rotation speed n ₂ and stopped, regardless of the dimensional accuracy of the bar 1. (For example, 2μ or 3μ).

Thereafter, in order to determine whether the clearance between the guide bush 18 and the bar 1 is proper, the spindle 6
Is rotated, the Z-axis servomotor 11 of the headstock moving device 8 is rotated, and the rod 1 held on the spindle 6 is guided by the guide bush 18
The control device checks the current value of the servo motor 11 at that time while moving it in the axial direction while rotating it. If this current value is equal to or less than the preset allowable value, it is determined that the clearance between the guide bush 18 and the bar 1 is appropriate, the adjusting operation of the inner diameter of the guide bush 18 is completed, and the machining operation is started. On the other hand, if this current value exceeds the above-mentioned allowable value, it is determined that the clearance between the guide bush 18 and the bar 1 has become too small, and an error signal is output.

After the operation of adjusting the inner diameter of the guide bush 18 is completed, the bar bush 1 is cut while the inner diameter of the guide bush 18 is maintained at the adjusted value (the servo motor 26 remains stopped). Is done. That is, the main shaft 6 rotates the rod 1, the guide bush 18 rotatably supports the rod 1, and the cutting work is performed by the blade 32 in the vicinity thereof. Here, since the clearance between the guide bush 18 and the bar 1 is set to be extremely small (for example, about 2 to 3 μ), the deflection of the bar 1 at the processing position is extremely small, and high-precision machining is possible. Is possible. The inner diameter of the guide bush 18 is maintained at the previously set value while machining the entire length of the rod 1 set on the spindle 6, but the dimensional accuracy in the longitudinal direction of the rod 1 is extremely good. There is no problem. When a new rod 1 is set on the main shaft 1, the above-described inner diameter adjusting operation of the guide bush 18 is performed to adjust the inner diameter of the guide bush to be appropriate for the rod.

When machining such as cutting while rotating the bar 1, as described above, the guide bush 18 rotatably holds the bar 1 through a very small clearance, but the bar 1 is rotated. There are also cases where processing is performed without allowing it. For example, machining may be performed with a cross drill, a milling machine, or the like while the rod 1 is not rotated. In this case, the processing may be performed with a predetermined clearance left between the guide bush 18 and the bar 1 as described above, but the diameter of the guide bush 18 may be reduced and the bar 1 may be processed.
It is better to tighten and to process in that state.

[0021]

As described above, according to the present invention, the inner diameter of the guide bush can be adjusted so as to always form a constant small clearance with respect to the rod member inserted into the guide bush. Therefore, even if there is a dimensional error between the rods, any rod can be supported through a certain minute clearance, high precision machining can be performed, and continuous machining of high precision parts is possible. The effect of doing is obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a spindle moving type lathe equipped with a guide bush device according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing an enlarged main part of the guide bush device.

FIG. 3 is a schematic front view thereof.

FIG. 4 is an operation flowchart for explaining the operation of the above embodiment.

[Explanation of symbols]

 1 Material 2 Spindle device 3 Bed 5 Spindle base 6 Spindle 13 Guide bush device 15 Guide bush holder 16 Sleeve chuck 17 Guide bush sleeve 18 Guide bush 22 Guide bush adjusting gear 26 Servo motor 31 Tool rest 32 Tool

Claims (1)

[Claims] 1. A guide bush, which is arranged in front of the main shaft so as to be non-rotatable on the same axis as the main shaft and rotatably supports a bar member held by the main shaft, and a guide bush inner diameter for adjusting an inner diameter of the guide bush. An adjusting mechanism, a servo motor for driving the guide bush inner diameter adjusting mechanism, and a controller for the servo motor are provided, and the controller is the inner diameter of the guide bush when a bar is inserted into the guide bush. Is provided to tighten the bar, and then the guide bush inner diameter has a function to control the servo motor so that the inner diameter of the guide bush is enlarged by a predetermined amount from the inner diameter when the bar is tightened. A guide bush device for a spindle-moving type lathe.