JPH1043902A - Drum processing device and processing method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a drum processing apparatus and method capable of improving roundness. SOLUTION: A rotation angle detector 24 which holds a workpiece (fixed drum 2) and detects a rotation angle of a main shaft 21 which rotates integrally, and a cutting tool 39 is brought into contact with a peripheral surface of the workpiece to be processed. A cutting mechanism 30 for machining the peripheral surface of the workpiece;
And a run-out detector 41 for detecting run-out of the cutting peripheral side surface of the workpiece with respect to the workpiece, and issues a command to correct the circumferential run-out of the primary-turned workpiece at each rotation angle.
In order to eliminate machining errors due to circumferential runout.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for cutting a drum used in a rotary head drum apparatus for magnetically recording / reproducing a signal on a magnetic tape with a DAT or VTR. is there.

[0002]

2. Description of the Related Art In a DAT, a VTR or the like, a rotary head drum device is used as means for magnetically recording and reproducing signals on a magnetic tape.

FIG. 8 shows an example of a general rotary head drum device for performing helical scan recording by using a rotating magnetic head 1. This rotary head drum device,
A fixed drum 2 attached to an apparatus body (not shown);
Rotating drum 3 attached to magnetic head 1 and integrally rotated
It is composed of Also, on the outer periphery of the fixed drum 2,
A lead surface 4 for guiding the tape is provided along the direction in which the magnetic tape T runs. In this rotary head drum device, a part of the magnetic tape T is wound around the rotary drum 3 and the tape running surface 8 of the fixed drum 2 along the lead surface 4 and is run obliquely. The magnetic head 1 performs helical scanning of the magnetic tape T to record and reproduce information.

As shown in FIG. 9, a shaft hole 2a is formed at the center of the fixed drum 2, and a bearing bore 7a for fixing the bearing 6 above and below the shaft hole 2a is provided. 7b is formed. The rotating shaft 5 is rotatably attached to the shaft hole 2a via a bearing 6 fixed to the bearing inner diameter portions 7a and 7b. In this structure, high precision coaxiality is required between the bearing inner diameter portion 7a and the tape running surface 8 in order to realize stable tape running. For this reason, the fixed drum 2 is usually
In the final turning step of the drum alone, accuracy is obtained by simultaneously turning the bearing inner diameter portion 7a and the tape running surface 8.

[0005]

However, as shown in FIGS. 10 and 11, for example, a motor component for rotating the rotary drum 3 is mounted on the fixed drum 2 in the rotary head drum device described above. In addition to the hole 9, the counterbore hole 10, and the tap 11, a notch 12 for drawing out wiring is formed, and most of them have a structure in which the balance is poor during turning. For this reason, in the thin part and the thick part, the amount of springback of elastic deformation due to cutting resistance is not uniform,
Further, the roundness of the tape running surface 8 deteriorates due to the intermittent cutting by the notch.

FIG. 12 is a view schematically showing a configuration of a conventional general drum lead processing machine for processing a fixed drum. The drum lead processing machine 50 is an NC machine tool (Numerical Control Machinetool). The X slider 52 is moved in a direction along the X axis (horizontal direction on the paper) by the driving of a motor 51, and the Z slider is driven by a motor 53. A Z-slider 54 that is moved together with the X-slider 52 in a direction along an axis (a vertical direction on the paper surface);
Tool holders 55 and 5 mounted on slider 52
6, a turning unit 57, and a motor 58 for sliding the turning unit 57 vertically at high speed in synchronization with the rotation angle of the fixed drum 2. Cutting tools 59, 60, 61 are attached to the tool holders 55, 56 and the turning unit 57, respectively.

In this drum lead processing machine 50, the fixed drum 2 is connected to the spindle 2 on the drum lead processing machine 50 side.
When the center is held at 1, and then the motor 63 attached to the main shaft 21 is rotated, the fixed drum 2 rotates integrally with the main shaft 21. In addition, when the turning unit 57 is slid at high speed in synchronization with the rotation angle of the fixed drum 2, turning on the peripheral surface of the fixed drum 2 can be performed.

However, this drum lead processing machine 5
At 0, since the Y-axis slider 65 of the turning unit 57 is slid at high speed in synchronization with the rotation angle of the fixed drum 2, as shown in FIG. The abrupt change in the force vector reduces the roundness of the tape running surface 8. FIG. 13 is a developed view of the peripheral side surface of the rotary drum 2, and FIG. 14 shows values obtained by actually measuring the roundness S1 of the tape running surface 8. In FIG. 14, one graduation is 0.4 μm, and reference numeral (A) in FIG. 14 denotes an uncut bulge 66 range, and (B) denotes an outermost diameter range. From this measured value, it can be seen that in the conventional fixed drum 2, during one rotation, the distance from the rotation center to the tape running surface 8 shows a lot of variation at each part, and the roundness is reduced. I understand.

In the tape running surface 8, the position of the slider 65 of the turning unit 57 is constant at each rotation angle. Therefore, as shown in FIG. If not straight (usually,
It is not completely straight and has a runout of about 1 μm or less.)
Means that the deviation from straightness is transferred as deviation from a perfect circle. That is, when the tape running surface 8 of the fixed drum 2 shown in FIG.
The straightness of the shaft slider 65 in the axial direction is not completely straight, and the tool 61 moved via the tool holder 37 is the same as FIG.
In the case where a movement causing undulation δ occurs in the portion indicated by the reference numeral 5 so as to expand outward with respect to the portion indicated by the reference numeral 5, the circumferential surface of the fixed drum 2 also
17 and the shifts corresponding to the portions indicated by the same reference numerals in FIG. 17 are transferred. In FIG. 15, the X-axis trajectory 67 of the cutting tool 61 is shown in an enlarged manner in the left part. FIG. 16 is a development view of the fixed drum 2, and FIG. 17 is an upper end view of the rotating drum 2.

Further, in the fixed drum assembling step, after press-fitting the bearing 6 on the press-fit side shown in FIG. 9, the adhesive is poured into the loose fit side, and thereafter, the adhesive is hardened by heating and holding at a certain temperature for a certain time. There is a process, but at this time, residual stress at the time of cutting is released, distortion may occur, and concentricity may deteriorate. In addition, due to any of the above or a combined action thereof, the apparent coaxiality is reduced, and the magnetic tape T sticks to the tape running surface 8 to cause hunting, which may adversely affect the running of the magnetic tape T. .

Although the above-mentioned phenomenon has high reproducibility in the same work (fixed drum 2), the deformation amount and the deformation direction between the works are not always constant. As means for solving the above problem, in the general drum lead processing machine shown in FIG. 12, the X slider 52 is reciprocated in the radial direction in synchronization with the rotation angle of the fixed drum 2 so that the X slider 5
What is necessary is to offset in the opposite direction the amount of deviation from a perfect circle when cutting is performed with 2 fixed. In other words, a hatched portion 9 in FIG. 18 is a portion where a deviation from a perfect circle occurs when cutting is performed with the X slider 52 fixed. Therefore, when the displacement of the portion 9 is offset in the opposite direction, as shown in FIG.
Can be obtained. The hatched portion 10 in FIG. 19 is a portion in which the displacement amount of the portion 9 is numerically corrected by the X slider 52, and the corrected portion 10 corresponds to the portion 9.

However, in the conventional drum lead processing machine, there is no detecting means on the processing machine for detecting the displacement. For this reason, if the offset amount is fixed, the deformation amount and the deformation direction are not always constant, so that satisfactory accuracy may not be obtained depending on the work. In addition, since the X slider 52 is mounted with the turning unit 57 and other tool holders which reciprocate in the rotation axis direction of the main shaft 21 in synchronization with the rotation angle of the main shaft 21, the inertia is increased due to the heavy weight. For this reason, it is difficult to perform high-speed machining by rotating the mechanism at, for example, 120 rotations or more per minute.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a drum processing apparatus capable of improving roundness. Another object is to provide a drum processing method that can improve the roundness. Further, other objects will be clarified sequentially in the contents described below.

[0015]

In order to achieve the above object, the present invention is characterized in that the following technical means are taken as a drum processing apparatus. That is, a workpiece holding and rotating unit having a main shaft that holds the workpiece and rotates integrally and a drive unit that applies a rotational force to the main shaft, and a rotation angle detector that detects a rotation angle of the main shaft. Cutting tool means having a blade at its tip for cutting the peripheral surface of the workpiece in contact with the peripheral surface of the workpiece and capable of reciprocating in a direction perpendicular to the rotation axis; and the main spindle. Detecting means for detecting the runout of the cutting peripheral side surface in the workpiece with respect to, and giving to the cutting tool means a command to correct the circumferential runout of the workpiece detected by the detecting means for each rotation angle, A control unit for reciprocating the cutting tool means in a direction orthogonal to the main shaft in synchronization with the rotation angle of the main shaft and giving a command to cut the workpiece again. .

Further, the following technical means is adopted as a drum processing method. That is, a rotation angle detector that detects the rotation angle of the main shaft that rotates together with the main shaft while holding the work together with the main shaft, and the blade is brought into contact with the peripheral surface of the main body that rotates with the main shaft so that the processing is performed. Cutting tool means for machining the peripheral surface of the workpiece, and detection means for detecting runout of the cutting peripheral side surface of the workpiece with respect to the main spindle, and the peripheral runout of the workpiece primarily turned by the cutting tool means Is given to the cutting tool means for each rotation angle so as to eliminate machining errors due to the circumferential runout.

According to this, after the workpiece is firstly turned first, the main shaft is then slowly rotated at, for example, about 20 rpm, and the circumferential runout of the firstly turned portion is detected at each rotation angle by the detecting means. Next, the cutting tool unit is controlled based on the detection result detected by the detection unit, and the primary turning is performed while correcting the peripheral surface of the workpiece for each rotation angle. As a result, it is possible to obtain a highly accurate rotary drum that eliminates processing errors due to circumferential runout.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall arrangement diagram of a VTR drum lead processing machine shown as an embodiment of the present invention. Note that, in FIG. 1, components denoted by the same reference numerals as those in FIGS. 8 to 19 correspond to FIGS. 8 to 19.

In FIG. 1, a fixed drum 2 to be processed is held at its center by a main shaft 21 on the drum lead processing machine side, and is rotated integrally with the main shaft 21. The main shaft 21 is connected to a motor 23 via a toothed timing belt 22, and the main shaft 21 and the fixed drum 2 are rotated by the rotation of the motor 23.
Rotate together. The main shaft 21 has a rotation angle detector 2.
4 is attached.

Next, the configuration of the lead processing machine will be described. This lead processing machine incorporates a computer (CNC) which numerically controls the entire processing machine.
zedNumerical Control) 25, a signal processing unit 26 which receives a rotation angle position signal of the main shaft 21 detected by the rotation angle detector 24 via the CNC 25, and synchronizes with the position signal to output a synchronization command signal; A driver 27 for amplifying a command signal from the unit 26 and outputting a voltage to the piezo element 28, and command data for calculating data from a shake detector 41 to be described later and instructing the signal processing unit 26 to cancel the circumferential runout of the fixed drum 2. A high-level device 29 such as a personal computer (PC), which sends a signal, a mechanical mechanism 30 for minutely displacing the cutting tool by the expansion and contraction of the piezo element 28, and a deflection of the peripheral surface of the fixed drum 2 held by the main shaft 21. And the like. In addition, although the shake detector 41 in the present embodiment uses an eddy current displacement meter, it does not matter if it is not an eddy current displacement meter. The signal detected by the shake detector 41 is amplified by the detector amplifier 42 and input to the host device 29. And the host device 2
Reference numeral 9 starts reading of shake data in response to a detection start signal from the CNC 25.

3 to 5 show the details of the mechanical mechanism 30. FIG. 3 is a side view, FIG. 4 is a partially cutaway top view, and FIG. 5 is a partially cutaway front view. is there. FIG.
5 to 5, the mechanical mechanism 30 has a base 32 mounted on the tip of a slider 65 of a turning unit 57 of a lead processing machine, and small slide guides 33 and 34 are mounted on the base 32. ing. When the piezo element 28 receives a command signal from the signal processing unit 26 via the driver 27 and expands / contracts, the displacement is changed by the leaf spring 3 fixed to the driving unit of the piezo actuator.
The slide guide 33,
The cutting tool 39 is transmitted in the order of the plate 40, the tool holder 37, and the cutting tool 39 on the cutter 34, and reciprocates the cutting tool 39 as a cutting blade at high speed. At this time, since the driving frequency of the piezo element 28 is high and the inertia of the driving part is small, it is possible to follow and process even when the main shaft 21 rotates at a high speed of, for example, 300 revolutions per minute or more. A cutting tool 39 is mounted on the tool holder 37, and the peripheral surface of the fixed drum 2 is turned with the tool 39. Thus, the running surface 8 of the fixed drum 2 in the rotary drum device of the VTR can be machined while finely adjusting in the radial direction with respect to the rotation axis.

FIG. 2 is a flowchart showing the operation of the main part in the apparatus of this embodiment. Therefore, using the flowchart of FIG.
The operation of the drum lead processing machine for a VTR according to the embodiment shown in FIGS. 3 to 5 will now be described.

First, in order to check the run-out of the fixed drum 2, which is an individual work, with respect to the main shaft 21, the tool holder 3 is used.
7 performs primary turning of the tape running surface 8 in a fixed state (step S1).

When the primary turning is completed, the spindle 21 temporarily stops at a fixed position, and then the spindle 21 is slowly rotated at about 20 rpm. At this time, the shake detector 41 outputs a signal corresponding to the distance from the fixed drum 2 to the detection amplifier 42, and the detection amplifier 42 amplifies the signal. And CN
The host device 29 starts reading the amplified signal in response to the detection start signal from C25. At this time, the host device 29
Detects the position signal of the rotation angle detector 24 attached to the main shaft 21 from the circuit of the CNC 25, fetches the data of the laser displacement meter at this timing, and obtains the amount of shake at each rotation angle (step S2).

Next, the host device 29 immediately calculates the operation amount data of the mechanical mechanism 30 for canceling the shake at each rotation angle with respect to the shake amount, and transfers it to the signal processing unit 26 as correction command data. (Step S3). When the transfer is completed, the signal processing unit 26 outputs a ready signal to CN
Output to C25 and start secondary turning (finish turning) (step S4).

When the secondary turning is started, the signal processing unit 26
Detects the position signal of the rotation angle detector 24 from the circuit of the CNC 25, and outputs a command signal corresponding to the correction command data created and transferred by the host device 29 to the driver 27 in synchronization with this. Then, the driver 27 amplifies the command signal and outputs the amplified command signal to the piezo actuator to expand and contract the piezo element 28. At this time, a strain gauge sensor for detecting the position is built in the piezo actuator, and the deviation from the command value is fed back to the driver 27 and is corrected (step S).
5).

When the piezo element 28 expands and contracts in accordance with a command, the displacement is transmitted to the plate 40 on the slide guides 33 and 34, the bite holder 37, and the joint via a joint using a leaf spring 35 fixed to the driving section of the piezo actuator.
It is transmitted in the order of the cutting tool 39. At this time, since the driving frequency of the piezo element is high and the inertia of the driving portion is small, it is possible to perform processing while following the high-speed rotation of the main shaft 21 at, for example, 300 rpm or more. In addition,
A cutting tool 39 is mounted on the tool holder 37, and the peripheral surface of the fixed drum 2 is turned by the cutting tool 39. Thereby, it is possible to process the tape running surface 8 of the fixed drum 2 in the rotary drum device of the VTR while finely adjusting the tape running surface in the radial direction with respect to the rotation axis. Thus, the roundness of the tape running surface 8 of the rotating drum 2 and
By improving the coaxiality with respect to the bearing inner diameter portion 7a, it becomes possible to manufacture a rotary head drum device that prevents hunting of a video tape.

FIGS. 6 and 7 show a fixed drum 2 processed using the present invention and a fixed drum 2 processed according to the prior art.
3 shows the results of actually measuring the coaxiality between the bearing inner diameter portion 7 and the tape running surface (lead outer diameter). 6 and 7, one scale is 0.4.
In μm, reference numeral 108 denotes the outer diameter of the lead of the fixed drum 2 (the outer diameter of the tape running surface 8), and reference numeral 109 denotes the inner diameter of the bearing of the fixed drum 2 (the inner diameter of the inner diameter portion 7a of the bearing). As can be seen by comparing FIGS. 6 and 7, in the fixed drum 2 shown in FIG. 7 to which the present invention is applied, compared to the conventional fixed drum 2 shown in FIG. It can be seen that there is no variation in the distance to the tape running surface 8 and the coaxiality is improved.

In this embodiment, the unit using the piezo element 28 has been described as the driving means for minutely displacing the cutting tool. However, a giant magnetostrictive material (TERFENOL-D) is used instead of the piezo element 28. However, the same effect can be obtained. In this case, since the displacement amount with respect to the entire length of the actuator is larger than that of the piezo element 28, the unit can be downsized. Also, a case has been described in which an eddy current displacement meter capable of detecting the deflection of the fixed drum 2 with respect to the main shaft 21 is used without contact, but a contact-type detector such as an electric micrometer may be used. It is not a problem.

[0030]

As described above, according to the present invention,
It is possible to expect effects such as obtaining a drum processing apparatus and a processing method capable of improving the coaxiality, that is, the roundness, of the outer peripheral surface of the rotary drum and the inner diameter of the bearing.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a drum processing machine for a VTR shown as an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of a main part of the processing machine;

FIG. 3 is a side view of a mechanical mechanism in the processing machine of the present invention.

FIG. 4 is a top view of a mechanical mechanism in the processing machine of the present invention.

FIG. 5 is a front view of a mechanical mechanism in the processing machine of the present invention.

FIG. 6 is a diagram showing the coaxiality without correction compared with the effect of the present invention.

FIG. 7 is a view showing the coaxiality of the fixed drum after correction by cutting with the lead processing machine of the present invention.

FIG. 8 is a side view showing an example of a general rotary head drum device.

FIG. 9 is a vertical sectional side view of a fixed drum in a general rotary head drum device.

FIG. 10 is a top view of a fixed drum in a general rotary head drum device.

FIG. 11 is a side view of a fixed drum in a general rotary head drum device.

FIG. 12 is a configuration layout diagram of a general lead processing machine.

FIG. 13 is a developed view of a peripheral surface of a fixed drum in a general rotary head drum device.

FIG. 14 shows measurement data of roundness of a fixed drum formed by a conventional processing method.

FIG. 15 is a diagram illustrating a process in which a processing deviation occurs in a conventional fixed drum.

FIG. 16 is a view illustrating a process in which a processing deviation occurs in a conventional fixed drum.

FIG. 17 is a diagram illustrating a process in which a processing deviation occurs in a conventional fixed drum.

FIG. 18 is a diagram illustrating a conventional method for correcting a processing deviation in a fixed drum.

FIG. 19 is a diagram illustrating a conventional method for correcting a processing deviation in a fixed drum.

[Explanation of symbols]

 2 Fixed Drum (Workpiece) 3 Rotary Drum 4 Lead Surface 7 Bearing Inner Diameter 8 Tape Running Surface 21 Spindle 24 Rotation Angle Detector 28 Piezo Element 30 Mechanical Mechanism (Cutting Tool Means) 37 (Bite) Holder 39 Cutting Byte 41 Runout detector

Claims (9)

[Claims] 1. A workpiece holding / rotating means having a main shaft which holds a workpiece and rotates integrally therewith, and a drive unit which applies a rotational force to the main shaft, and a rotation angle which detects a rotation angle of the main shaft. Detector, Cutting tool means having a blade at its tip for cutting the peripheral surface of the workpiece abutting on the peripheral surface of the workpiece and capable of reciprocating in a direction orthogonal to the main axis, Detecting means for detecting a run-out of the cutting peripheral side surface of the workpiece with respect to the rotation axis; and a command for correcting the circumferential run-out of the workpiece detected by the detecting means for each rotation angle to the cutting tool means. And a controller for giving a command to re-cut the workpiece by reciprocating the cutting tool means in a direction orthogonal to the spindle in synchronization with the rotation angle of the spindle. And drum processing equipment. 2. The drum processing apparatus according to claim 1, wherein a piezo element is used as driving means for reciprocating the cutting tool means in a direction orthogonal to the main axis. 3. The drum processing apparatus according to claim 1, wherein a giant magnetostrictive material is used as a driving means for reciprocating the cutting tool means in a direction orthogonal to the main axis. 4. The drum processing apparatus according to claim 1, wherein an eddy current displacement meter is used as the rotation angle detector. 5. A rotation angle detector for detecting a rotation angle of a main shaft that rotates integrally with holding a workpiece, and a blade that abuts a peripheral surface of the workpiece that rotates together with the main shaft. Cutting tool means for processing the peripheral surface of the workpiece; and detecting means for detecting runout of a cutting peripheral surface of the workpiece with respect to the main shaft, wherein the workpiece is primarily cut by the cutting tool means. A drum correction method for giving a command to correct the circumferential runout for each rotation angle to the cutting tool means to eliminate the circumferential runout. 6. A piezo element is used as driving means for bringing the blade of said cutting tool means into contact with said workpiece.
2. The drum processing method according to 1. 7. The drum machining method according to claim 5, wherein a giant magnetostrictive material is used as a driving unit for bringing a blade of the cutting tool unit into contact with the workpiece. 8. The drum processing apparatus according to claim 5, wherein an eddy current displacement meter is used as the rotation angle detector. 9. The magnetic head according to claim 5, wherein a rotary head drum for a magnetic recording / reproducing machine having a lead surface for guiding a magnetic tape and a tape running surface on a peripheral side surface is processed as the workpiece. Drum processing method.