JPH04161834A - Torque measuring system - Google Patents

Abstract

PURPOSE:To remove the effect of disturbance in the torque measurement of an arm for supporting a magnetic head by computing the value of the torque with a transfer-function measuring device based on the output of a torque measuring device. CONSTITUTION:An arm 6a is held with a positioning pin 14 in one of specified base positioning holes 16a-16c. Under this state, the output signal from a transfer-function measuring device 17 is made to flow through a coil 7a by way of an amplifier 187, and the arm 6a is shaked. The acceleration at this time is detected with a piezoelectric acceleration type vibration pickup 11 which is fixed to the arm 6a and outputted into the device 17 through a charge amplifier 19. The device 17 leads out the equivalent mass force constants of the specified positioning holes 16a-16c based on the outputs of the amplifiers 18 and 19. The torque constants are computed based on the mass force constants.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a torque measurement method, and particularly to a torque measurement method for an arm supporting a magnetic head of a magnetic disk device.

[Conventional technology]

In the conventional torque measurement method, as shown in FIGS. 4 and 5, an arm 6b having the same moment of inertia as the arm supporting the magnetic head is driven, and a tension gauge 40 is used to measure the load F. Torque was being detected.

The arm 6b is attached to the base 1b by the arm holder mechanism 30.
A driving coil 7b is fixed to the end opposite to the end supporting the magnetic head with a screw 10c. The coil 7b has a hook 60 fixed at the center of the end opposite to the end fixed to the arm 6b with an adhesive or the like, and is moved by a magnetic circuit 12 fixed to the base 1b with a screw 10b. It is clamped as much as possible.

The arm holder mechanism 30 includes a shaft 5 attached to a base 1b, bearings 2a and 2b whose inner rings are fixed to the shaft 5, and an arm holder 4 attached to the shaft 5 via the bearings 2a and 2b. , the bearing 2 is penetrated by the shaft 5 inside the arm holder 4.
a and the arm holder 4; a spacer 8 that fixes the arm 6b and the coil 7b to the arm holder 4; 4 & an arm clamper <9 fixed with screws 10a. The arm holder 4 has a cylindrical shape and includes an annular spring holding part 4a on the inside of the lower part and a collar-shaped arm holding part 4 on the outside of the lower part.
b). The coil spring 3 is attached to the arm holder 4
It is penetrated by the shaft 5 inside the bearing 2a and is attached between the outer ring of the bearing 2a and the spring holding part 4a. In the bearings 2a and 2b, forces are applied to the inner and outer rings in opposite directions and parallel to the shaft 5 in order to eliminate rattling.

In the bearing 2a, the outer ring has a gap between it and the arm holder 4 and receives an upward force from the coil spring 3, and the inner ring is fixed above the shaft 5 and the outer ring receives an upward force. It is receiving force downward. In the bearing 2b, the inner ring is fixed below the shaft 5, and the outer ring is fixed to the arm holder 4. Therefore, due to the weight of the arm holder 4, arm 6b, etc., the outer ring receives force downward and the inner ring receives force upward. ing. The spacer 8 has a cylindrical shape that covers the outer diameter of the arm holder 4, and includes the arm 6b and the coil 7b.
In order to press the coil 7b, it has a notch corresponding to the cross section of the coil 7b. The arm clamper 9 has an annular shape with a hole the same size as the inner diameter of the arm holder 4.

When measuring torque, a current value i is applied to the coil 7b. As a result, the arm 6b to which the coil 7b is fixed rotates in the rotation direction C0 around the shaft 5 of the arm holder mechanism 30, and the coil 7b also rotates in the rotation direction C2. . The tension gauge 40 is hooked onto the hook 60 of the coil 7b, pulled to a specified position in the tensioning direction of the tension language gauge in the direction opposite to the rotational movement direction C2, and the load F in that state is measured using the tension gauge 40. next,(
4) As shown in the formula, the load F is multiplied by the application point distance rl from the center point E of the shaft 5 to the application point G of the tension gauge, which is the installation position of the hook 60, and divided by the current value i. Torque constant Kt was calculated.

[Problem to be solved by the invention]

In the conventional torque measurement method described above, the value varies greatly depending on the pulling position, angle, direction, nonlinear components of the spring, etc., so in order to increase the speed of the device and reduce power consumption, it is necessary to There is a problem in measuring the torque linearity of a magnetic disk device, where the value is a problem, because there is a large error.

In addition, the torque when the coil is energized is the load F due to the attraction and repulsion caused by the magnetic flux of the magnet and the magnetic flux generated in the coil.
It is determined by the distance r1 of the point of application of the tension gauge, and minute irregularities and curvatures due to changes in the point of force due to the movement of the coil and changes in the linkage magnetic path length are eliminated within the variation when measured with the tension gauge. There is a problem with this.

SUMMARY OF THE INVENTION An object of the present invention is to provide a torque measurement method that can calculate a torque value close to the true value with little error, regardless of the influence of other disturbances.

[Means to solve the problem]

The torque measurement method of the present invention includes a torque measurement device that measures torque, and a transfer function measurement device that outputs a measurement signal to the torque measurement device and calculates a torque value from the output of the torque measurement device. .

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention. The same embodiment uses a torque measurement wave 220 for measuring the torque of the arm.
, a transfer function measurement wave 217 that outputs a measurement signal to the torque measurement device 20 and calculates a torque value from the output, and a transfer function measurement wave [17 that amplifies the measurement signal outputted by It is comprised of an amplifier 18 that outputs the output to the transfer function measuring device 17 again, and a charge amplifier 19 as a preamplifier that amplifies the output of the torque measuring device 20.

FIG. 2(a) is a front view of the torque measurement wave 20 of the same embodiment, and FIG. 2(b) is a sectional view taken along line BB in FIG. 2(a).

The torque measurement wave W20 of the same embodiment is the base 1b of the conventional example.
The arm 6b and coil 7b are replaced with the base 1a, arm 6a and coil 7a of the same embodiment, and a positioning pin 14 is also provided. Arm 6a having the same moment of inertia as the arm carrying the magnetic head
The piezoelectric acceleration type vibration pickup 11 is fixed with adhesive or the like in the circumferential direction of the arm 6a at the same position as the read/write point of the magnetic head, and the piezoelectric acceleration type vibration pickup 11 is fixed to the arm 6a in the circumferential direction. An arm positioning hole 15 opened on the side of the arm holder mechanism 30 from the B-7 cup 11;
It has an O-ring 13 for wL force inserted into the arm positioning hole 15. The base 1a to which the arm holder mechanism 30 is rotatably attached has an arm positioning hole 1 centered around the position where the arm holder mechanism 30 is attached.
The base positioning holes 16a, 16b, and 16c are circumferentially bored and aligned with the base positioning holes 16a, 16b, and 16c. The positioning pin 14 is connected to the O-ring 13 of the arm positioning hole 15,
Any one of base positioning holes 16a, 16b, 16c
The end portion of the arm 6a is fixed by penetrating through the two holes. In addition, in FIG. 2(a), the positioning pin 14 is inserted into the base positioning hole 16.
However, the base positioning hole 16b is not shown because it is hidden by the arm 16a.

Next, the operation of this embodiment will be explained using FIG. 1 and FIG. 2. The arm 6a is held in one of the predetermined positioning holes 16a, 16b, and 16c by a positioning pin 14.

In this state, the transfer function measuring device 17 outputs the measurement signal 17a, and the output signal 18a is sent to the coil 7 via the amplifier 18.
a to vibrate the sink arm 6a. At this time, the piezoelectric acceleration type vibration pickup 11 fixed to the arm 6a converts the generated acceleration A into a charge 11a, and the charge amplifier 1
Output to 9. The charge amplifier 19 amplifies the charge and outputs it as an output signal 19a to the transfer function measuring device f17. In the transfer function measurement wave [17, the output signal 19a and the output signal 18a when the current i is passed from the amplifier 18 to the coil 7a are input, and the output signal 18a is inputted to the predetermined positioning holes 16a, 16
b, derive a force constant (hereinafter referred to as equivalent mass force constant) K F / m that includes the equivalent mass (mass of arm 6) m of 16C.

Figure 3 shows the equivalent mass force constant K derived as described above.
It is an explanatory diagram showing p/m. In the transfer function measuring device 17, the equivalent mass force constant KF/m is expressed by the logarithm of equation (1).

KFA −= −= Y ,,... (1) m
i Here, using the flat frequency position (Xs+z) of the curve of the equivalent mass-force constant Kr/m as a reference, monitor the level (Yo) of the equivalent mass-force constant Kp/m at this time, and calculate this value by formula (2). Convert to an exponent as shown in .

Here, the torque constant ↑ is determined by the force constant KF and the distance from the center point E of the shaft 5 to the force point H of the coil 7 (hereinafter referred to as force point distance), 2, so the second half of formula (3) is established. do.

K = Kp , the torque constant is calculated.

〔Effect of the invention〕

As explained above, the present invention measures the torque generated by a coil and a magnetic circuit using a piezoelectric acceleration converter, thereby reducing the influence of other disturbances and achieving a torque that is close to the true value with little error. It has the effect that the value can be calculated.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2(a)
is a front view of the torque measuring device 20 of the same embodiment, and FIG.
) is a cross-sectional view taken along line B-B in FIG. It is a sectional view taken along the line A-A in the figure. la, lb...Base, 6a, 6b...
・Arm, 7a, 7b...Coil, 11...
...Piezoelectric acceleration type vibration big a tube, lla...
...Charge, 12...Magnetic circuit, 13...
...O-ring, 14...Positioning pin, 15
...Arm positioning holes, 16a, 16b, 16
c...Base positioning hole, 17...Transfer function measuring device, 17a...Measurement signal, 18.
...Amplifier, 18a... Output signal, 19
...Charge amplifier, 19a...Output signal, 20-...Torque measuring device, 30...
...Arm holder mechanism. Agent Patent Attorney Uchihara Sound No. 7 Sen (b) ffi21J (Hz) χ 3 Zue 4 Figure

Claims (1)

[Claims] 1. A torque measuring device that measures torque, and a transfer function measuring device that outputs a measurement signal to the torque measuring device and calculates a torque value from the output of the torque measuring device. Torque measurement method. 2. The torque measuring device includes an arm having the same moment of inertia as the arm supporting the magnetic head, an arm holder mechanism that rotatably holds the arm, and a base to which the arm holder mechanism is attached. an acceleration-type vibration pickup fixed at the same position as the read/write point of the head of the arm; and an arm positioning hole opened on the arm holder mechanism side from the fixed acceleration-type vibration pickup of the arm. , a buffer O-ring inserted into the arm positioning hole, and a circumference centered on the position where the arm holder mechanism of the base is attached, aligned with the arm positioning hole on the base. a plurality of drilled base positioning holes; a positioning pin that passes through the O-ring of the arm positioning hole and the base positioning hole and fixes the end of the arm to the base; and the acceleration type of the arm. It is characterized by having a coil fixed to an end opposite to the end to which the vibration pickup is fixed, and a magnetic circuit movably sandwiching the coil and fixed to the base. Torque measurement method.