JP3349588B2 - Guide bush adjustment method for NC automatic lathe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting a guide bush in an NC automatic lathe for processing a bar which adjusts a gap between the bar and a guide bush.

[0002]

2. Description of the Related Art Adjustment of a guide bush is an indispensable step in order to guarantee high machining accuracy in an NC automatic lathe for machining a bar, and in order to maintain machining accuracy and prevent seizure. Although it is necessary to adjust the gap to an appropriate value, there has been no known method for automatically adjusting the gap.
The conventional method of adjusting the guide bush is to insert the bar into the guide bush, slide the bar in the axial or rotational direction while tightening the adjustment nut, and intuitively check the resistance between the bar and the guide bush It is determined whether the gap between the bar and the guide bush is appropriate, and is adjusted so that the gap is appropriate while taking into account the material, dimensions (diameter), and maximum number of revolutions of the bar. Was.

[0003]

In the above-mentioned prior art, the adjustment is made by human sense so as to obtain an appropriate frictional resistance while taking into account the material, dimensions (diameter), maximum number of revolutions and the like of the bar, so that it is troublesome. In addition to this, there are problems such as the need for special and advanced skills based on many years of experience, and large variations in adjustment due to differences in the skill levels and senses of workers.

SUMMARY OF THE INVENTION An object of the present invention is to provide a guide bush adjusting method for an NC automatic lathe which can be adjusted quickly and always so as to have an appropriate gap without any variation in adjustment by an operator.

[0005]

According to the present invention, there is provided a guide bush for guiding a bar, and the gap between the bar and the guide bush is adjusted by screwing the guide bush. In an NC automatic lathe equipped with an adjustment nut, an adjustment pin is provided on a cap nut of the spindle.
At the same time, the adjusting pin is inserted into the adjusting nut.
The adjusting pin and the adjustment are provided by providing a aligning pin hole and rotating the spindle with a servomotor that drives the spindle.
Rotating the adjusting nut through the pin hole, the servo
The torque of the motor is measured by the torque measuring
The predetermined tongue input in advance to the determination means and stored in the determination means
Is determined reaches or torque, the servo motor is temporarily stopped driving by the servo motor upon reaching a predetermined torque, after the adjustment pin removed from the adjusting pin hole, gripping the bar in the collet chuck Measure the frictional resistance between the bar and the guide bush by driving the spindle in the rotation direction or the axial direction, and terminate the adjustment of the adjustment nut when detecting that the resistance value of the frictional resistance has reached a predetermined value. It is characterized by.

[0006]

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. As shown in the headstock moving type NC automatic lathe shown in FIG. 1, a spindle 2 for gripping a bar 1 is rotatably supported by a headstock 3, and the headstock 3 is a bed 4.
It is provided so as to be slidable in the main shaft center line direction. As is well known, a chuck sleeve 5 is inserted into the front end side of the main shaft 2 so as to be rotatable together with the main shaft 2 and slidable in the direction of the main shaft center line. A collet chuck 6 for gripping the bar 1 is inserted into the front end of the chuck sleeve 5, and the collet chuck 6 is urged forward by a compression coil spring (not shown) mounted in the chuck sleeve 5. Have been. A cap nut 7 for receiving the front end of the collet chuck 6 is screwed to the leading end of the main shaft 2.

On a bed 4 in front of the spindle 2, a guide bush support 1 which is integrated with a tool rest support (not shown)
0 is fixed, and the guide bush support 10
The guide bush holder 11 is fixed on an extension of the main shaft center line. A guide bush 12 (in this embodiment, a fixed guide bush) that guides and supports the bar 1 is fitted inside the front end side of the guide bush holder 11. In the guide bush 12, the tip of a key pin 13 fixed to the guide bush holder 11 is inserted into a key groove 12a formed in the outer peripheral portion so as not to rotate. Is performed. An adjusting nut 15 is screwed into a threaded portion at the rear end of the guide bush 12, and the gap between the guide bush 12 and the bar 1 can be adjusted by the adjusting nut 15. The above is the known structure of the headstock moving type NC automatic lathe for bar machining.

In this embodiment, a plurality of (six in this embodiment) adjustment pin insertion holes 7a are provided on the same circumference at the front end of the main shaft 2 inside the cap nut 7. In the insertion hole 7a, the same number of adjustment pins 20 are slidable in the axial direction, and the tips are disposed so as to protrude toward the adjustment nut 15. And, in the adjustment pin insertion hole 7a,
A spring 21 is mounted so as to urge the adjustment pin 20 toward the adjustment nut 15, and a screw 22 is screwed into a screw formed in the adjustment pin insertion hole 7 a of the cap nut 7. The adjustment nut 15 is provided with the same number of adjustment pin holes 15a into which the adjustment pins 20 are inserted.

FIG. 2 shows a control device of a spindle servomotor 30A for driving the spindle 2 in rotation and a headstock servomotor 30B for driving the headstock 3 in the direction of the spindle center line in the present embodiment. The control device is a servo motor 30A, 30B
A torque measuring means 31A, 31B for measuring the rotational torque of these servomotors 30A, 30B; and a torque setting means 33 for presetting the rotational torque of the servomotors 30A, 30B to a predetermined rotational torque by an input means 32 such as a keyboard. And determination means 35A, 35B for determining whether the measurement results of the torque measurement means 31A, 31B have reached the rotation torque set in the torque setting means 33.
And The servo motors 30A, 30B and the constant torque output means 34A, 34B are automatically controlled according to a procedure preprogrammed in the control means 36, and the judgment results of the judgment means 35A, 35B are inputted to the control means 36. At the same time, it is input to the display means 37 of the display,
The completion of the adjustment is displayed on the display means 37 of the display, as well as by an alarm sound, a lamp, and the like.

Next, a method of adjusting the guide bush 12 according to the present embodiment will be described with reference to FIG. Input means 32
When the guide bush adjustment mode of the control means 36 is selected and started 40, the headstock 3 moves 41 to the origin position of the adjustment cycle. That is, when the headstock 3 is at the most advanced position (at a position where the headstock 3 can be advanced most at the time of machining, the adjustment pin 20 is in the adjustment pin hole 15 of the adjustment nut 15).
(a position away from a), and the collet chuck 6 of the spindle 2 is opened. Here, the bar 1 is inserted into the main shaft 2 and the unadjusted guide bush 12. In this state, the start signal 4 by the push button switch or the control device
2 to input an adjustment start signal.

The guide bush adjustment process is controlled by a procedure programmed in the control means 36 in accordance with the input of the adjustment start signal. First, the bar 1 is gripped by closing the collet chuck 6 of the spindle 2. Then the main spindle 2, for example 10~50min-1 as low speed adjusting nut 15 rotates Shinano grounds headstock 3 in clamping direction, that the adjustment pin inserting step 43 of the main shaft 2 is slowly advanced in the direction of the guide bush 12 is Done. Here, the advance of the main shaft 2 is further about 1 mm from the position where the adjustment pin 20 contacts the adjustment nut 15.
Move forward about. As the main shaft 2 advances, the adjustment pin 2
0 is temporarily pushed back toward the cap nut 7 by contacting the rear end face of the adjusting nut 15, but is adjusted by the urging force of the spring 21 when the adjusting pin hole 15 a of the adjusting nut 15 and the adjusting pin 20 coincide with each other due to the low speed rotation of the main shaft 2. Pin 20
Engages with the adjustment pin hole 15a. After rotating the main shaft 2 by 60 ° or more (when the number of the adjusting pins 20 is six), the main shaft 2 is rotated so that the adjusting pins 20 are sufficiently engaged with the adjusting pin holes 15a.
Advance further.

Next, the rotation of the spindle 2 is gradually increased, and the adjustment nut 15 is rotated in a direction in which the gap between the rod 1 and the guide bush 12 is reduced (the spindle servo motor 30A is driven).
44. As a result, the rotation of the main shaft 2 is transmitted to the adjustment nut 15 via the adjustment pin 20, and the adjustment nut 15 is rotated so that the gap between the rod 1 and the guide bush 12 is reduced. In this case, the torque of the spindle servomotor 30A when the spindle 2 rotates the adjustment nut 15 via the adjustment pin 20 is measured by the torque measurement unit 31A and input to the determination unit 35A. Then, it is determined 45 whether or not the torque measured by the torque measuring means 31A has reached the predetermined torque stored in the determining means 35A beforehand input to the torque setting means 33. Here, the predetermined torque previously input to the torque setting means 33 is determined and input in advance by experimentally investigating the material, dimensions (diameter), and maximum rotation speed of the bar 1. Then, when the determining means 35A determines that the driving torque of the spindle servomotor 30A has reached a predetermined torque, the control means 36 stops the rotation of the spindle servomotor 30A according to the determination result.
6 The display means 37 displays the completion of the torque adjustment.

Normally, the adjustment may be completed as it is. However, when the gap is to be adjusted with higher precision, it is determined whether the gap between the guide bush 12 and the bar 1 adjusted as follows is appropriate. Check and readjust.

If the adjusted clearance between the guide bush 12 and the bar 1 is confirmed and readjusted, the spindle 2, ie, the headstock 3, is retracted after the first adjustment step. 50, the adjustment pin 20 is separated from the adjustment pin hole 15a. Then, the normal cutting state, that is, the adjusting pin 2
0 is separated from the adjustment pin hole 15a of the adjustment nut 15 and the barstock 1 is gripped by the collet chuck 6 of the spindle 2, and either the sliding of the headstock 3 in the forward or backward direction or the rotation of the spindle 2 or these The determination 51 is made by measuring the frictional resistance between the bar 1 and the guide bush 12 in the combination of. The frictional resistance is determined by the torque of the servomotor 30A or 30B when the headstock 3 is moved forward or backward or the spindle 2 is rotated without inserting the rod 1 through the spindle 2 and the guide bush 12, and the rod 1 Is inserted into the main shaft 2 and the guide bush 12, and the bar 1 is gripped by the main shaft 2 to slide the main shaft 2 forward or backward, or the torque of the servo motors 30A and 30B when the main shaft 2 is rotated. Can be determined by comparing. As a result of the determination 51, if the frictional resistance is within the predetermined range, it is determined that the adjustment has been properly performed, and the adjustment is completed 52. The headstock 3 is moved 53 to the origin, and the guide bush adjustment process is completed 54.
Then, the guide bush adjustment mode is canceled.

If the frictional resistance is not within the predetermined range,
If the frictional resistance is insufficient, the process returns to the adjusting pin inserting step 43, and the subsequent adjusting step is repeated. If the frictional resistance is too large, the adjustment nut 15 is once loosened sufficiently and the adjustment process is repeated again. That is, when the frictional resistance is insufficient, the main shaft 2 advances again, and the adjustment pin 20 provided on the cap nut 7 of the main shaft 2 is inserted into the adjustment pin hole 15a of the adjustment nut 15, and the guide described above. Guide bush 1 by the gap adjustment method of bush 12
Readjust the gap between 2 and bar 1. In this case, in order to insert the adjustment pin 20 into the adjustment pin hole 15a, the adjustment nut 1
5 adjustment pin hole 15a and cap nut 7 adjustment pin 2
Since it is only necessary to match the phase with 0, a complicated operation such as the first step is unnecessary.

The torque for turning the adjusting nut 15 is compared by the judging means 35A with a torque larger by a small amount α than the torque set in the first guide bush adjusting step as a set torque value. If the frictional resistance is too large, as described above, the adjusting nut 15 is once loosened sufficiently and the adjusting step is repeated again. The set torque value at this time is a small amount α from the set torque in the first adjustment process.
Is subtracted. After the second adjustment step is completed, the main shaft 2 is retracted again, and the frictional resistance between the bar 1 and the guide bush 12 is measured. This is repeated, and the process ends when a predetermined frictional resistance is reached. Also, the torque setting means 33
, The torque corrected as described above is automatically set, and thereafter, the corrected torque is used.

The above description is directed to an optimum embodiment in which a servomotor is used as a drive source for rotating the spindle 2 or slidingly driving the headstock 3. If the drive source is a servo-controlled hydraulic cylinder, the stop of the headstock 3 may be detected using the constant torque output 34B instead of the torque measuring means 31B and the judging means 35B. Can be implemented.

FIGS. 4 and 5 show another embodiment of the present invention. This embodiment is an example in which a rotary guide bush in which the guide bush 12 rotates in synchronization with the main shaft 2 is applied to an NC automatic lathe, and shows an example in which the present invention is applied to an NC automatic lathe disclosed in Japanese Utility Model Publication No. 62-25281. 1 and 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 4, the spindle servomotor 3
The rotation of 0A is transmitted to the first intermediate shaft 61 via the belt 60. The first intermediate shaft 61 is provided in parallel with the main shaft 2, and drives the main shaft 2 to rotate via a timing pulley 62, a timing belt 63, and a timing pulley 64. First
The intermediate shaft 61 is a spline, and a timing pulley 62 is fitted into the spline, transmits rotation, and is slidable in the axial direction. Also slides on the main shaft 2
The driving force is transmitted to the motor. When the main shaft 2 slides in the front-rear direction, the rotation of the headstock servomotor 30B is converted into linear motion by the ball screw 65, and the headstock 3 moves along a guideway (not shown).

FIG. 5 shows the details of the drive system from the first intermediate shaft 61 to the rotary guide bush 70. The rotation guide bush 70 is attached to the guide bush support 10, and includes a guide bush holder 11 rotatably supported by a bearing 72 in an outer sleeve 71 fixed to the guide bush support 10. A gear 11a is formed at the rear end of the guide bush holder 11, and a tapered surface is formed at the inner diameter of the tip. The guide bush 12 is inserted into the gear 11a and fastened and fixed with an adjustment nut 15, and By tightening the adjusting nut 15, the inner diameter of the guide bush 12 is adjusted. A seal 74 is provided at the tip of the rotary guide bush 70 to prevent cutting oil, chips and the like from entering the bearing 72.

A gear 80 is fixed to the end of the first intermediate shaft 61, and a gear 82 provided on the second intermediate shaft 81.
Is engaged. A torque limiter 83 is provided between the second intermediate shaft 81 and the gear 82 as an overload safety device, and detects an overload and stops the machine. Second intermediate shaft 81
Is rotatably supported by the housing 84 and the housing 8
4 is fixed to the guide bush support 10. The above configuration is the same as the conventional configuration.

In this embodiment, a clutch brake means 90 for transmitting or not transmitting the rotation of the second intermediate shaft 81 to the guide bush 12 is provided. Hereinafter, the clutch brake means 90 has a well-known structure, and transmits the driving force of the second intermediate shaft 81 when the clutch is ON.
5 and 11a to the guide bush holder 11, and when the brake is ON (clutch OFF), the second intermediate shaft 8
1 is turned off and the guide bush holder 11
, And the gear 85 is non-rotatably fixed by the brake. The clutch brake means 90 is controlled on / off by the control means 36 shown in FIG.

Therefore, when the clutch of the clutch brake means 90 is used, the second intermediate shaft 81 and the gear 85 are connected. Therefore, the rotation of the servo motor 30A is
And the rotation of the first intermediate shaft 61 is transmitted to the main shaft 2 via the timing pulley 62, the timing belt 63, and the timing pulley 64. The rotation of the first intermediate shaft 61 is performed by the gears 80 and 82 and the second intermediate shaft 81.
And transmitted to the guide bush 12 via the guide bush holder 11 with the gear 11a.

On the other hand, when the clutch is turned off, the brake is turned on, and the second intermediate shaft 81 is separated from the gear 85, so that the rotation of the second intermediate shaft 81 is not transmitted to the guide bush 11, and the gear 85 rotates. Immobilized, gear 85
The guide bush holder 11 that meshes with is also fixed non-rotatably. Therefore, by providing the adjustment pin 20 on the cap nut 7 of the spindle 2 and the adjustment pin hole 15a on the adjustment nut 15 as in FIG. Thereby, the gap between the guide bush 12 and the bar can be adjusted.

[0026]

[0027]

In each of the above embodiments, the guide bush 12
The adjustment is not limited to the case where the bar is replaced, and may be performed each time the bar 1 is replaced. That is, when the bar 1 is replaced, the gap between the guide bushes 12 is loosened, the bar 1 is replaced, and the guide bush 12 is adjusted. In this way, a constant gap can always be ensured even when the outer diameter of the bar 1 varies greatly, and the end surface of the bar 1 is chamfered to be inserted into the guide bush 12. Becomes unnecessary. Also, a headstock fixed type in which a tool post (guide bush) moves can be similarly applied. In addition, the servo actuator is not limited to the servo motor, and may be, for example, a hydraulic motor or a hydraulic cylinder (including a rotary actuator).

[0029]

According to the present invention, there is provided an NC automatic lathe having a guide bush for guiding a bar and an adjusting nut screwed into the guide bush to adjust a gap between the bar and the guide bush. Adjust the adjustment nut on the spindle nut.
And the adjustment pin is inserted into the adjustment nut.
The adjustment pin holes to be input provided by rotating the spindle by a servo motor for driving the spindle, the adjusting pin
And rotating the adjustment nut through the adjustment pin hole ,
The torque of the servomotor is measured by torque measuring means.
Input to the torque setting means in advance and stored in the determination means.
It is determined whether the torque reaches the predetermined torque.When the servo motor reaches the predetermined torque, the drive by the servo motor is temporarily stopped, and the adjusting pin is removed from the adjusting pin hole. The main spindle holding the gripper is driven in the rotation direction or axial direction to measure the frictional resistance between the bar and the guide bush, and when it is detected that the resistance value of the frictional resistance has reached a predetermined value, the adjusting nut is adjusted. Since the adjustment is completed, there is no variation in the adjustment by the operator, and the adjustment can be quickly and always performed so that an appropriate gap is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a guide bush adjusting device for an NC automatic lathe according to the present invention.

FIG. 2 is a block diagram showing a control device of the NC automatic lathe of FIG. 1;

FIG. 3 is a flowchart of control of the NC automatic lathe in FIG. 1;

FIG. 4 is a sectional view showing another embodiment of the guide bush adjusting device of the NC automatic lathe according to the present invention.

FIG. 5 is an enlarged view of a main part of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bar material 2 Main shaft 7 Cap nut 12 Guide bush 15 Adjustment nut 15a Adjustment pin hole 20 Adjustment pin 30A Spindle servomotor 30B Spindlehead servomotor 31A, 31B Torque measurement means 33 Torque setting means 35A, 35B Judgment means 36 Control means

Continuation of the front page (56) References JP-A-7-164207 (JP, A) JP-A-2-83103 (JP, A) JP-A-59-64204 (JP, A) JP-A-5-228703 (JP, A) , A) Japanese Utility Model Showa 58-173402 (JP, U) Japanese Utility Model Showa 59-171002 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B23B 13/12

Claims (2)

(57) [Claims] 1. An NC automatic lathe having a guide bush for guiding a bar and an adjusting nut screwed into the guide bush to adjust a gap between the bar and the guide bush, the cap nut of the main shaft is adjusted. With pins
The adjustment pin into which the adjustment pin is inserted into the adjustment nut
The adjustment pin and the adjustment pin are provided by rotating the spindle with a servo motor that drives the spindle.
Rotating the adjusting nut through the hole, the servomotor
The torque of the motor is measured by the torque measurement
A predetermined torque previously input to the gear and stored in the determination means
Is determined has been reached, once stops driving by the servo motor when the servo motor has reached a predetermined torque,
After removing the adjustment pin from the adjustment pin hole , measure the frictional resistance between the bar and the guide bush by driving the spindle holding the bar with the collet chuck in the rotation direction or the axial direction,
The adjustment of the adjusting nut is terminated when it is detected that the resistance value of the frictional resistance has reached a predetermined value.
Guide bush adjustment method for C automatic lathe. 2. The frictional resistance between the rod and the guide bush is
2. The guide bush adjusting method for an NC automatic lathe according to claim 1, wherein the determination is made based on a torque of a spindle motor that rotates the spindle or a headstock motor that moves the spindle in the axial direction.