JPS6278783A - Oscillating dual actuator - Google Patents

Abstract

PURPOSE:To attain the assembly of a head arm with no attachment/detachment of a bearing having the severe coupling conditions, by using a fixed shaft that can be attached to an detached from a housing. CONSTITUTION:The head arms 13 and 13' and arm spacers 29 and 29' are fixed in lamonation to an assembly composed of rotary cylinders 11and 11' to a fixed shaft 10. Then the coil supporters 14 and 14; are connected to the assembled. Thus an oscillating matter is assembled. This assembly is set into a housing 19 consisting of a member 9, a sub-base 21 and a top plate 20 so that the coils 15 and 15' are inserted into the gaps of permanent magnets 16 and 16' respectively. Then the lower and upper ends of the shaft 10 are fixed to the base 21 and the plate 20 respectively. In such a way, the assembly of a dual actuator is through. Thus it is possible to assemble a head arm with no attachment/detachment of a bearing.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention compactly implements two oscillating actuators. The present invention relates to a swing type actuator for a magnetic disk device.

[Conventional technology]

In most conventional magnetic disk drives, one actuator corresponds to one disk spindle to write and read information. However, i&Ken's large-capacity magnetic disk device has been proposed in which two actuators are provided for one disk spindle to improve the device's processing capacity, and it has not been put into practical use. It is provided.

[Problem that the invention seeks to solve]

There is a dual actuator configuration in which multiple actuators are placed on one disk spindle, in which individual actuators are placed around the disk spindle, but in this configuration, the area occupied by the actuator becomes large and the device becomes difficult to operate. It has a serious drawback of being large.

On the other hand, Japanese Patent Application Laid-Open No. 58-23362 discloses a structure in which a plurality of swing actuators are arranged with high mounting density by comprising a plurality of rotary carriages that are independently rotatably supported around a common fixed shaft. The structure of an oscillating dual actuator is disclosed. This structure is shown in Figure 4 (-)
, shown in (b). To explain this simply, reference numeral 10 is a fixed shaft whose lower end is fixed to the subspace 21, and is relative to the fixed shaft 10.

Rotary carriages 11 and 11'K, head arms 13 and 13', and flat coils 15 and 15', each supported independently and swingably by bearings 12 and 12'.
The coil supports 14 and 14' that supported the 2
It constitutes a set of rocking bodies. Since this type of oscillating dual actuator shares a shaft, the bearing is inevitably used with the inner ring fixed and the outer ring rotating. A preload is equally applied to the four bearings 12 and 12' by a preload spring 22 via a spacer 23 between the upper bearing 12' and the lower bearing 12. 16, 16' are permanent magnets,
17, 17', and 18 are yokes that form a magnetic circuit. Reference numeral 19 denotes a magnetic circuit housing, and this housing 19 is composed of the sub-space 21, a top plate 20 that supports the upper end of the fixed shaft 10, and a box-shaped member 9 interposed between the top plate 20 and the sub-space 21. has been done. 25, 26, 25' and 28' are stopper mechanism assemblies that define the swinging range of each swinging body. The head arms 13 and 13' are connected to the rotary carriages 11 and 11' by draw bolts 24.

By the way, in order to improve the dynamic positioning performance of a swing actuator for magnetic disks, it is necessary to improve the transfer function (mechanical impedance , S) are required to be constant up to high frequencies. In other words, in the structure shown in FIG. 4, the coil supports 14, 14', the rotary carriages 11, 11', and the head arms 13, 1
It is necessary that the 3' bonded body including the bonded portion has high rigidity. In addition, the head arms 13 and 13' are required to have high dimensional stability in the swing direction (Fig. 4 (in-plane direction of the pass) and in the height direction (axial direction).
, 13' is equipped with a dedicated servo head (not shown) that reads position signals written in advance on the magnetic disk surface, and each oscillator moves based on this position information. 2 positioning, but the other head arm is displaced relative to the arm on which the servo head is mounted (hereinafter referred to as servo arm) in the swinging direction due to swinging or thermal strain.

The magnetic head that performs reading will no longer be positioned at an accurate position. In addition, if the dimensional accuracy in the height direction of the head arms 13 and 13' is poor, the flying characteristics of the floating magnetic head, which flies up to a submicron flying clearance with respect to the magnetic disk surface mounted on the tip and rotating nine times, may be affected. There is a risk that the high-speed rotating disk and magnetic head may come into contact and destroy the recorded information.

As mentioned above, in the swing type multi-actuator shown in FIG. 4, the head arm 13,
13' is coupled to the rotary carriages 11 and 11', the rigidity of the coupling portion is insufficient and the mechanical impedance of the swinging punch cannot be sufficiently increased. Further, the head arms 13, 13' are pressed against the reference surfaces of the rotary carriages 11, 11' by the tension of the draw bolts 24, but the draw bolt tension to ensure the bonding force is act as component forces applied to each reference plane in the swing direction, arm longitudinal direction, and height direction, respectively. These component forces are ideal.

It is only necessary to apply vertical force to each reference plane.

In reality, it is a complex system that includes frictional force, and strain perpendicular to the surface and shear strain caused by the frictional force occur on the bonding surfaces. If an impact force that exceeds the frictional force is applied to the head arm in this coupled state, there is a risk that the head arm will deviate from the reference position and not return to its original position. In addition, the head arm may deviate from its normal position due to changes in the strain produced on the reference surface due to changes in ambient temperature, or due to deformation of the reference surface itself. There is no problem with this kind of change in the position of the Hiko head arm if the change is quantitatively the same as that of the servo head arm, but due to variations in the two parts, variations in the draw bolt tension, etc., a minute relative displacement occurs, and the servo head Even if the recording/reproducing head is accurately positioned, the recording/reproducing head may deviate from the original recording track, resulting in poor operation as a storage device.

Furthermore, the height component of the draw bolt tension is:

It joins the height direction reference plane of the carriages 11, 11' and defines the height of the head arms 13, 13'.

In other words, the draw bolt tension and the reaction force from the carriage reference plane are applied to the head arms 13, 13' and balanced. To explain in more detail, the draw bolt tension is the fourth
As shown in the figure, the reaction force is applied at a constant angle to the longitudinal direction of the head arms 13, 13', and is received from the reference planes on two substantially orthogonal sides of the rotary carriages 11, 11'. That is, since an asymmetrical force is applied to the longitudinal direction of the head arms 13, 13', the head arm having a thickness of approximately 3 to 4 mm undergoes warping or twisting deformation. Therefore, the draw bolt tension must be strictly controlled so that this head arm deformation does not exceed a certain amount. If there are two magnetic heads mounted on the tip of the head arm (one magnetic head corresponds to the disk surface), it is relatively easy to pull the magnetic head as you only need to manage the height of one place on the magnetic head mounting surface at the tip. However, in the case of a structure in which four magnetic heads are mounted at the tip of the head arm (two magnetic heads correspond to the disk surface) as shown in Figure 4, it is possible to manage the heights of the two tips at the same time. If deformation accompanied by twisting occurs, it becomes impossible to control the dimensions of the head arm in the height direction.

On the other hand, examples of the structure of a swing type actuator that does not use the draw bolt coupling method include Japanese Patent Application Laid-open No. 55-67975, Japanese Utility Model Application No. 56-9582, or Japanese Patent Application No. 55-59965.
There is a structure disclosed in the issue.

FIG. 5 shows a structural diagram thereof, and elements having the same functions as those in FIG. 4 are given the same numbers, and their explanations are omitted.

This is achieved by stacking and fixing a flat head arm 13 having a circular hole that fits into a rotary cylinder 11 that is rotatably supported with respect to a fixed shaft 10 and sequentially fitting it into the rotary cylinder 11. A multi-head arm 13 that constitutes a swinging body and is different from the draw bolt connection method.
It has a structure that does not apply stress that would cause zero warping or torsional deformation. Furthermore, since the coil support body 14 can be directly connected to the head arm 13, there is an advantage that the rigidity of the rocking body is also improved. but.

An example in which this structure is applied to an oscillating multi-actuator is not disclosed. A rotary cylinder 11 is rotatably supported via bearings 12 and 12' with respect to a fixed shaft 10 which is fixed to a sub-base 21 by a method such as press fit or shrink fit.

The support part 31 is required for stacking and fixing the head arm 13, that is, a step is required at the bottom to serve as a reference surface for the stacked arms. Therefore, even if this structure is simply configured in two steps, the rotary This is because the head arm 13 having a circular hole that fits into the cylinder 11 cannot be fitted into the lower rotary cylinder. To make this possible, the rotary cylinder 11 can be easily attached and detached, and a rocking body in which the head arm 13 is stacked and fixed to the rotary cylinder 11 can be set on the fixed shaft 10, but highly accurate fitting conditions are required. It is extremely difficult to insert the inner or outer rings of the bearings 12, 12' each time the head arm 13 is attached or detached. Rather, the inner and outer rings of the bearings 12 and 12' are all press-fitted or bonded, except for the mating surfaces (the inner ring of the bearing 12' in Figure 5), which must necessarily be loosely fitted in order to provide preload. Since fitting conditions without backlash must be achieved by methods such as these, it is difficult to configure the rotary cylinder 11 so that it can be easily attached and detached.

In addition, in FIG. 5, 27 is a screw for fixing the laminated arm 13 to the rotary cylinder 11.

28 is a connecting bottle for connecting and fixing each arm to each other;
29 indicates the distance between the head arms 13 as v! This is an arm spacer that regulates and regulates 4 positions.

[Means for solving problems]

The oscillating dual actuator according to the present invention has been developed to solve the above-mentioned problems, and is independently rotatably supported with respect to a fixed shaft.

and two rotary cylinders disposed symmetrically with respect to a road surface with respect to a virtual center plane perpendicular to the fixed axis.

The head arm is fitted into each rotary cylinder and fixed in a layered manner, a driving coil and a coil support body that provide driving force to the head arm, and a member forming a magnetic circuit, and the fixed shaft is connected to the nozzling. It is configured to be detachable.

Another aspect of the present invention provides two rotary cylinders rotatably supported on a fixed shaft and disposed symmetrically with respect to a road surface with respect to a virtual center plane orthogonal to the fixed shaft, and each rotary cylinder It is equipped with a head arm that is fitted into the cylinder and fixed in a stacked manner, a driving coil and a coil support body that provide driving force to the head arm, and a member that forms a magnetic circuit, and the fixed shaft is detachable from the nozzle. A servo arm equipped with a servo head for reading positional information written on the magnetic disk surface is arranged in a plane symmetrical position with respect to a virtual center plane perpendicular to the fixed axis. It is.

[Effect]

In the present invention, since the fixed shaft is configured to be detachable from the nozzle, the head arm can be assembled without attaching or detaching the bearing, which has strict fitting conditions.

Further, in another aspect of the present invention, the two rotary cylinders and the servo arm are arranged in plane-symmetrical positions with respect to a virtual central plane perpendicular to the fixed axis.
The inertia of each rocking body can be made almost the same.

Therefore, the drive system parameters of each rocking body are substantially the same, ensuring the sameness as a dual actuator.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a partially cutaway side view showing an embodiment of a swing type dual actuator according to the present invention, and FIG. 2 is a partially cutaway side view of the same actuator. In these figures, components having the same functions as those shown in FIGS. 4 and 5 are designated by the same reference numerals.

Reference numeral 10 denotes a fixed shaft that is removably fixed to the sub-base 21 and the top plate 20 that together with the member 9 constitute the nine-piece ring 19, and 11 and 11' (however, 11 is not shown) are fixed to the fixed shaft 10. Bearings 1za, 1zb, t2'
Rotary cylinders 13° and 13' are rotary cylinders 11 and 11' that are rotatably supported via pins m and 1z'b and arranged symmetrically to a virtual central plane A- perpendicular to the fixed axis 10. A flat head arm having a circular hole that fits into the rotary cylinders 11 and 11'.
The arm spacers 29 and 29' are stacked and fixed together with the arm spacers 29 and 29'.

27, 27' are screws for fixing the laminated arms 13, 13' to the rotary cylinders 11, 11', 2B
.

28' is a connecting pin that connects and fixes each head arm 13, 13' and arm spacer 29, 29' to each other. 15 and 15' are flat drive coils fixed to the coil supports 14 and 14';
4, 14' are spacer arms 29a, 29' located almost at the center of the rocking body! It is coupled and fixed to a protrusion provided on the magnetic circuit side of L, and provides a driving force to the oscillator. Bearing 12
Preload is applied to m, 12b, 11a, and l2'b by preload springs 22 and 22', respectively.

The central bearings 12b, 12'b are positioned using the step 31 provided at the center of the fixed shaft 10 as a reference plane, and are fixed by press fitting or adhesive, and the shaft end bearings 128, 12'
The inner ring of & is fitted with a loose fit in order to stably apply preload. This play in the inner ring is absorbed by applying radial preload by springs 32 and 32' built into the fixed shaft 10.

Note that a similar play absorption mechanism may be provided by making the inner rings of the bearings 12b and 12'b on the center side of the shaft loose. 16°16
' is a permanent magnet, 1γ, 17', and 18 are yokes, which form a magnetic circuit. 37°37' is an arm presser.

This dual actuator is assembled in the following steps. First, the rotary cylinders 11, 11 are attached to the fixed shaft 10.
After the head arms 13, 13' and the arm spacers 29, 29' are stacked and fixed on the assembly in which the coil supports 14, 14' are connected, the assembly of the oscillator is completed. This assembly is arranged in a housing 19 consisting of the member 9, the sub-base 21 and the top plate 20 so that the coils 15 and 1da are inserted into the gap between the permanent magnets 16 and 16'. The upper ends are each sub-base 21. The assembly of the dual actuator is completed by fixing it to the top plate 20.

Note that 30 and 30' are holding plates for fixing the fixed shaft 10 to the sub-base 21° and the top plate 20. The method of fixing the fixed shaft 10 is not limited to this embodiment, and the sub-base 21. As long as it can be stably fixed to the reference plane provided on the top plate 20,
A variety of methods are available, including direct screw fixing and fixing methods that utilize the wedge effect.

Since the present invention has the structure as explained above,
There is no warpage or twisting deformation of the head arms 13, 13'.
The coupling portion that causes bending vibration of the oscillator is the coil support 1.
4. Joint part 1 between 14' and arm spacer 29°29'
This makes it possible to realize a dual-arm oscillating actuator with a highly rigid oscillating body. In addition, in the nine embodiments shown in FIGS. 1 and 2, each rocking body has four head arms 13 and 13', so the central arm is arranged so that the driving force is applied to the center of gravity of the rocking body. Spacer 2
9a.

The structure is such that the coil supports 14 and 14' are connected to the tortoise 29', but if the number of head arms of each oscillator is an odd number, the coils are similarly connected to the magnetic circuit side of the head arm located in the center. Mounting surfaces for the supports 14, 14' are provided and bonded. Not only in oscillating actuators but also in linear actuators, the center of gravity of the movable part, the point of application of the driving force, and the center of the movable part support point (in Fig. 2, the bearing 1
21-12b.

It is well known among those skilled in the art that by matching the center of 12/a - 12'b, it is possible to suppress the achieved vibrations that adversely affect positioning performance.

Furthermore, the most important characteristic regarding the vibration of the magnetic disk actuator is the vibration transfer function between the servo head that reads the positioning reference signal and the coil supports 14 and 14' that support the coil that provides the driving force. It is necessary that this remains constant up to the high frequency range. Therefore, the servo arm is required to be more vibrationally stable than other data arms. To achieve this, it is effective to make the servo arm a different structure and size from the data arm by making the plate thicker or strengthening the frame structure. In this case as well, it is important that the center of gravity of the oscillator is configured to coincide with the center of the point of application of the driving force and the point of support of the oscillator. As mentioned above, in the embodiment of the present invention shown in FIGS. 1 and 2, the movable parts are arranged symmetrically with respect to the virtual central figure, so the center of gravity of both rocking bodies is also at A-. Be in a symmetrical position with respect to the plane. Figure 2 shows the case where the servo arm has the same structural dimensions as the data arm, so in this case, the servo arm may be placed at any position 2, for example, the second from the bottom of each oscillator. .

FIG. 3 shows another embodiment of the invention. head arm 13
, 13', 13m and 13'a are servo arms, and the structure is shown when the plate thickness is thicker than that of the other head arms. Other structural elements are similar to the structure of the above embodiment. For the upper rocking body, servo arm 13a' is placed second from the bottom, and for the lower rocking body, servo arm 1 is placed second from the bottom.
1 is placed third from the bottom, that is, they are placed in a plane symmetrical position with respect to the virtual central figure -N, so that the center of gravity of each rocking body is in a symmetrical position with respect to the A-A1 plane. ing. Therefore, when the center of gravity 1-, the point of application of the driving force, and the center of the support point of each oscillating body of the oscillating dual actuator are made to coincide with each other, this can be achieved by performing exactly the same operation for each of the upper and lower oscillating bodies.

In other words, although each of the rocking bodies shown in FIGS. 2 and 3 has an asymmetric structure with respect to the axial direction, it is impossible to align the center of gravity of each rocking body with the center plane of the driving force application point and the support point. This can be easily realized by calculating the center of gravity position at the design stage, or by installing balance weights at the arm pressers 3γ and 37', for example. When using the method of installing a balance weight, it is possible to adjust VVS by changing the balance weight υ even if the deviation of the center of gravity of each rocking body is not the same, but depending on the thickness, etc. By arranging the servo arms, including the positions of the servo arms having structures with different dimensions, in plane symmetry with respect to the virtual central plane A-,
The balance weights to be installed in the arm pressers 37 and 37' need only be of approximately the same amount, so that the inertia of each rocking body can be made approximately the same. This makes it possible to make the drive system parameters of each oscillating body almost the same, ensuring the sameness as a dual actuator.

Productivity 2. Stability of positioning characteristics can be improved.

〔Effect of the invention〕

As explained above, the swing type dual actuator according to the present invention is supported so as to be able to swing independently about the fixed axis, and is arranged plane symmetrically with respect to the virtual central plane A- which is orthogonal to the fixed axis. The oscillator is composed of a head arm that is fitted into two rotary cylinders and fixed in a stacked manner, and the fixed shaft is detachably attached to the housing, so the head arm can be assembled without attaching or detaching the bearing. Accordingly, it is possible to realize an oscillating dual actuator with laminated arms, which is free from a decrease in the rigidity of the oscillating body and from recoil and torsional deformation of the head arm due to the draw bolt connection method. K has the advantage that the positioning accuracy of the oscillating dual actuator can be dramatically improved with a compact configuration, the positioning speed can also be increased, and the performance of the magnetic disk drive can be improved.

In addition, in the present invention, the servo arm equipped with the servo head is arranged in a plane symmetrical position with respect to the virtual center plane perpendicular to the fixed axis, so the parameters of the drive system of each oscillator can be set almost the same. This not only ensures the sameness as a dual actuator, but also improves productivity and stability of positioning characteristics.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view showing one embodiment of the swing type dual actuator according to the present invention, FIG. 2 is a partially cutaway side view of the same actuator, and FIG. 3 is another embodiment of the present invention. 4(-) and (b) are a partially cutaway side view and a partially cutaway side view showing a conventional oscillating dual actuator, and FIG. 5 is a conventional arm laminated single actuator. FIG. 3 is a partially cutaway side view showing the actuator. 10--Fixed shaft, 11, 11'...φ rotary carriage or rotary cylinder, 12, 12
', 121L, 12b, 12'&, 12'b -----
Bearing, 13, 13'* 11 @ II to 7 door arm, 131L13'1k-0, Servo arm, 14,1
4'・φ... Coil support, 15.15'... Drive coil, 16°16'... Permanent magnet, 1γ, 11
', 1B...Yoke, 1911111111 housing, 20...Fist top plate, 21...Sub pace. Patent applicant Nippon Telegraph and Telephone Corporation NEC Corporation

Claims (2)

[Claims] (1) Two rotary cylinders that are rotatably supported independently around a fixed axis and arranged symmetrically with the road surface with respect to a virtual center plane orthogonal to the fixed axis, and are fitted into each rotary cylinder and laminated. It is characterized by comprising a fixed head arm, a driving coil and a coil support body that provide a driving force to the head arm, and a member forming a magnetic circuit, and the fixed shaft is configured to be detachable from the housing. Oscillating dual actuator. (2) Two rotary cylinders that are rotatably supported independently of a fixed axis and arranged symmetrically to the road surface with respect to a virtual center plane perpendicular to the fixed axis, and each rotary cylinder is fitted and laminated. The head arm is provided with a fixed head arm, a driving coil and a coil support for applying a driving force to the head arm, and a member forming a magnetic circuit, and the fixed shaft is configured to be detachable from the housing. A rocking motion characterized in that a servo arm equipped with a servo head for reading position information written on the magnetic disk surface is arranged at a position symmetrical to a virtual central plane perpendicular to the fixed axis. Type dual actuator.