JPH0766635B2 - Magnetic disk unit - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device including a plurality of magnetic disks and a plurality of magnetic heads respectively provided for the plurality of magnetic disks.

[Prior Art] In general, in order to reduce the size of a magnetic disk device or increase the packing density of magnetic disks, the distance between the magnetic disks is narrowed.

However, in a commonly used bulk head using a ferrite material, when the distance between the magnetic disks is narrowed to a predetermined value or more, signal interference occurs between the servo head for positioning and the data head for reading and writing data. May occur, and reading and writing of data may be hindered.

Since this signal interference occurs because the head itself is formed of a magnetic material, it can be eliminated by using a thin film head for all the heads, but if all the heads are thin film heads, the manufacturing cost increases.

[Problems to be Solved by the Invention] Therefore, as a reference example, as shown in FIG. 11, a magnetic disk device using a thin film head 1a as a servo head and a bulk head 1b as a data head is conceivable.

A plurality of magnetic disks 8a and 8b are laminated on the same spindle 9 at a predetermined interval.

The thin film head 1a and the bulkhead 1b made of a ferrite material include a guide arm 5 extending from the carriage 11 in the direction of the spindle 9, and elastic load arms 3a and 3b and a gimbal via spacers 4a and 4b.
Supported by 2,2.

As shown in FIG. 12, the load arms 3a and 3b are fixed to the guide arm 5 by bolts 7 and 7 via spacers 4a and 4b, respectively.

The guide arm 5 includes a thin film head 1a and a bulk head.
An FPC (flexible printed circuit) 6 for transmitting an electric signal from 1b to an external circuit (not shown) is provided.

The thin film head 1a and the bulk head 1b have the same distance from the carriage 11 to the ends 21a, 21b of the heads 1a, 1b on the spindle 9 side so that the drive range of the carriage 11 is not narrowed. It is provided.

However, the thin film head 1a and the bulk head 1b have different positions of the cores 22a and 22b in the track width direction due to their structures.

In such a magnetic disk device, the magnetic disks 8, 8, ...
Of the magnetic disk 8, the heads 1a, 1b, the load arms 3a, 3b, etc.
When thermally expanded, mainly due to the difference in the positions of the cores 22a and 22b of the servo thin film head 1a and the data bulkhead 1b,
Thermal off-track will occur.

This thermal off-track generation mechanism will be described with reference to FIG.

In the figure, since the gimbals 2 and 2 are made of the same material as the load arms 3a and 3b, they can be considered to be a part of the load arms 3a and 3b in calculating the thermal off-track, and thus omitted. I am doing it.

When the dimension of each member is written as R or l and the linear expansion coefficient of each member is written as α, the thermal off-track amount δ when the temperature change is ΔT ° C is δ = {(Rsα _di −l ₁ α _{t + l 2 α sa + l} 3 α gu) - (Rdα di -l 6 α d + l 5 α sb + l 4 α gu)} × ΔT ... (1) and represented.

It is assumed that each member is made of aluminum for the magnetic disks 8a and 8b and the guide arm 5, the thin film head 1a is made of ZrO ₂ , the bulk head 1b is made of MnZn, and the load arms 3a and 3b and the gimbal are made of SUS304.

The linear expansion coefficient and dimensions of each member are shown below.

α _di ＝ 23.5 × 10 ^-6 ℃ ^-1 α _t ＝ 7.8 × 10 ^-6 ℃ ^-1 α _d = 10.8 × 10 ^-6 ℃ ^-1 α _sa ＝ α _sb = 16.8 × 10 ^-6 ℃ ^-1 α _gu ＝ 23.5 × 10 ^-6 ℃ ^-1 Rs-Rd ＝ 1.3mm, l ₁ ＝ 2.9mm, l ₂ ＝ l ₅ ＝ 25mm l ₃ ＝ l ₄ , l ₆ ＝ 1.6mm… (2) ΔT ＝ 40 ℃ Therefore off From the equation (1), the track δ is δ = {(Rs−Rd) α _di −l ₁ α _t + l ₆ α _d } ΔT = (1.3 × 23.5 × 10 ⁻⁶ −2.9 × 7.8 × 10 ⁻⁶ +1. 6 × 10.8 × 10 ^-6 ) × 40 = 1.01 × 10 ^-3 mm = 1.01 μm.

In a magnetic disk device having a magnetic head with different core positions in the track width direction, such as a thin-film head for servo and a bulk head for data, when the temperature changes, thermal off-track occurs and the error rate increases. However, there is a problem in that the data becomes expensive and the information cannot be read out reliably.

In particular, when the temperature change exceeds 40 ° C., the thermal off-track amount δ = 1.01 μm as described above, and the error rate is extremely high in the current magnetic disk device with a track interval of 10 μm to 20 μm. It becomes too high and normal information cannot be read.

An object of the present invention is to provide a magnetic disk device having magnetic heads having different core positions in the track width direction, the thermal off-track amount can be reduced even if the temperature of the magnetic disk device changes, and information can be read reliably. Another object of the present invention is to provide a magnetic disk device capable of performing the above.

[Means for Solving the Problems] A first invention relating to a magnetic disk device for achieving the above object is to provide a plurality of magnetic disks and a plurality of magnetic heads respectively provided for the plurality of magnetic disks. In a magnetic disk device including: a core of the predetermined magnetic head due to thermal expansion; and a core of the predetermined magnetic head between a support member that supports a predetermined magnetic head among the plurality of magnetic heads and a member joined to the support member. Compensate for the difference between the change in the track width direction distance from a predetermined magnetic head to the magnetic disk and the change in the track width direction distance from the core of another magnetic head to the other magnetic head due to thermal expansion. It is characterized in that it is provided with a compensating member.

Here, the support member means a load arm, a guide arm,
A gimbal or the like is provided to support the magnetic head from a carrier that drives the magnetic head.

A second aspect of the present invention relates to a magnetic disk device, wherein a predetermined magnetic head of a plurality of the magnetic heads is supported, and a core of the predetermined magnetic head due to thermal expansion is tracked to a magnetic disk with respect to the predetermined magnetic head. A support whose length is set so as to be able to compensate for the difference between the change in the width direction and the change in the track width direction distance between the core of another magnetic head and the magnetic disk with respect to the other magnetic head due to thermal expansion. It is characterized by having a member.

A third invention relating to a magnetic disk device supports a predetermined magnetic head of a plurality of the magnetic heads, and tracks a core of the predetermined magnetic head by thermal expansion and a magnetic disk for the predetermined magnetic head. A support member having a linear expansion coefficient capable of compensating for the difference between the change in the width direction and the change in the track width direction distance between the core of the other magnetic head and the magnetic disk with respect to the other magnetic head due to thermal expansion. It is characterized by that.

According to a fourth aspect of the present invention relating to a magnetic disk device, among a plurality of the magnetic heads, a predetermined magnetic head has two or more cores in the track width direction, and the predetermined magnetic head has two or more cores. Of the two or more cores of the predetermined magnetic head among the cores, a change in a track width direction distance between the core of the predetermined magnetic head and the magnetic disk with respect to the predetermined magnetic head due to thermal expansion; The core having the smaller difference between the core of the other magnetic head and the change in the distance in the track width direction between the magnetic disk and the other magnetic head due to expansion is set to be capable of reading or writing information. It is a thing.

Either one of the predetermined magnetic head and the other magnetic head may form a bulk head, and the other may form a thin film head.

[Operation] When the magnetic disk device is driven, various motors and the like are driven, and the temperature of the magnetic disk device rises. Moreover, if the environmental temperature rises, the temperature further rises.

A magnetic disk, a magnetic head, a support member that supports the magnetic head, and the like thermally expand due to temperature rise.

The relative distance in the track width direction between the magnetic disk and the core of the predetermined magnetic head and the other magnetic head changes.

However, a change in the track width direction distance between the core of the predetermined magnetic head and the magnetic disk with respect to the predetermined magnetic head due to thermal expansion, and the core of another magnetic head due to thermal expansion and the magnetic disk with respect to the other magnetic head. And the change in the distance in the track width direction are compensated by the compensating member or the supporting member whose length and linear expansion coefficient are appropriately set.

Further, the common change amount in each change in the distance in the track width direction can be compensated by the carrier that drives the magnetic head in the track width direction.

Therefore, since it is possible to compensate for the change in the distance in the track width direction, it is possible to reduce the thermal off-track amount in the magnetic disk device having the magnetic heads having different core positions in the track width direction.

Further, in the case where one of the predetermined magnetic head and the other magnetic head forms the bulk head and the other forms the thin film head, the thermal off-track amount can be reduced and the bulk head and Since the thin film heads and the thin film heads do not interfere with each other even if they operate at the same time, the heads can be narrowed and miniaturization can be achieved.

[Examples] Various examples of the present invention will be described below with reference to Figs. 1 to 8.

In the various embodiments and the reference example, the same parts are designated by the same reference numerals, and the description thereof will be omitted.

A first embodiment of the magnetic disk device will be described with reference to FIGS.

As shown in FIG. 4, the magnetic disk device includes magnetic disks 8a, 8b, ... Stacked at predetermined intervals, and a spindle 9 for supporting and rotating the magnetic disks 8a, 8b.
A motor 10 for driving a spindle, head assemblies 20a and 20b in which magnetic heads 1a, 1b, ... Are incorporated, and a magnetic head 1
A linear type carriage 11 that moves a, 1b, ... In the track width direction of the magnetic disks 8a, 8b, a guide rail 13 that regulates the moving direction of the carriage 11, and a carriage 11 moves smoothly on the guide rail 13. Bearings for 12
And a coil that forms a linear motor for driving the carriage
14 and a magnetic circuit 15, a base 16 on which the various devices are placed, and a cover 17 that covers the various devices.

A servo magnetic disk 8a is mounted on the top of the spindle 9, and a data magnetic disk 8b is mounted below.

Further, a head assembly 20a in which a servo thin film head 1a and a data bulkhead 1b are incorporated is provided at the top of the carriage 11, and only the data bulkhead 1b is incorporated below. A head base body 20b is provided.

As shown in FIGS. 1 and 2, the head assembly 20a includes a thin film head 1a, a bulkhead 1b, and gimbals 2,2.
, The load arms 3a, 3b, the guide arm 5, the spacers 4a, 4b, 4c interposed at the joints between the load arms 3a, 3b and the guide arm 5, and the transmission of signals between the magnetic heads 1a, 1b and the outside. And an FPC 6 for performing.

The thin film head 1a is fixed to the main part of the gimbal 2 having elasticity. The gimbal 2 is an elastic load arm.
Fixed to the end of 3a, the load arm 3a is
It is fixed to the guide arm 5 with bolts 7 and 7 via c. The guide arm 5 is fixed to the main part of the carriage 11.

Further, the bulkhead 1b is fixed to the main part of the elastic gimbal 2 like the thin film head 1a, and the gimbal 2 is fixed to the end of the elastic load arm 3b. The load arm 3b is fixed to the guide arm 5 with a bolt 7 via a spacer 4b.

A change in the track width direction distance between the core 22a of the thin film head 1a and the servo magnetic disk 8a due to thermal expansion, and the core 22b of the bulk head 1b and the data magnetic disk 8 due to thermal expansion.
The compensating spacer 4c for compensating the difference in the change in the distance from b is
As shown in FIG. 3, it is provided between the load arm 3a supporting the thin film head 1a and the guide arm 5.

The compensating spacer 4c is provided with two bolt holes in the track width direction.

The load arm 3a and the compensating spacer 4c are connected by a bolt 7 screwed into a bolt hole on the spindle 9 side of the compensating spacer 4c.

The compensating spacer 4c and the guide arm 5 are connected by a bolt 7 inserted through a bolt hole on the carriage 11 side of the compensating spacer 4c.

The thin film head 1a and the bulk head 1b have the same distance from the carriage 11 to the ends 21a and 21b of the heads 1a and 1b on the spindle 9 side so that the driving range of the carriage 11 is not narrowed. Is provided.

Thus, although the thin film head 1a and the bulk head 1b have the same mounting position in the track width direction, the positions of the cores 22a and 22b in the track width direction are different due to their structures.

Each member is made of aluminum for the magnetic disk 8 and the guide arm 5, ZrO ₂ for the thin film head 1a, MnZn for the ferrite head 1b,
The load arms 3a, 3b, the gimbals 2, 2 and the spacers 4a, 4b, 4c are made of SUS304.

In this embodiment, the supporting member is the gimbal 2, the load arms 3a and 3b, and the guide arm 5.

Next, the setting of the distance between the bolt holes of the compensating spacer 4c will be described with reference to FIG.

The distance between the bolt holes is l ₂ s, and the distances from the spindle-side ends 21a, 21b of the magnetic heads 1a, 1b to the cores 22a, 22b are l ₁ , l ₆ .

The dimensions of each member are shown in equation (4) Rs-Rd = 1.3 mm, l ₁ = 2.9 mm, l ₂ = l ₅ = 25 mm, l ₂ s + l ₃ = l ₄ (4) The linear expansion of each member The coefficient is the same as that of the equation (2) described above.

When the temperature change amount is ΔT, the thermal off-track amount δ is δ = {(Rsα _di −l ₁ α _t ＋ l ₂ α _sa ＋ l ₂ sα _sa ＋ l ₃ α _gu ) − (Rdα _di −l ₆ α _d ＋ l ₅ α _sb + l ₄ α _gu )} × ΔT (5)

In order to satisfy δ = 0 for all values of ΔT, the following equation (6) may be established.

_{(Rsα di -l 1 α t +} l 2 α sa + l 2 sα sa + l 3 α gu) - (Rdα di -l 6 α d + l 5 α sb + l 4 α gu) = 0 ... (6) (4), ( When the value of l ₂ s at which δ = 0 is obtained in consideration of the equation 6), the following is obtained.

Therefore, if the load arm and the guide arm are connected using a compensating spacer with a bolt hole spacing of 3.8 mm,
Even if the temperature changes, the thermal off-track amount is always 0.
Can be

Although the example of SUS304 has been described as the material of the compensating spacer 4c, it is needless to say that the thermal off-track amount can be set to 0 with other materials as well by setting the dimensions in the same manner.

Next, a second embodiment of the present invention will be described with reference to FIGS.

In the head assembly 20c of this embodiment, the load arm 3c on the side of the thin film head 1a is made longer than the load arm 3b on the side of the bulkhead 1b, and other parts have the same structure as that of the reference example. There is.

As shown in FIG. 7, the load arm 3c on the thin film head 1a side extends toward the carriage 11 side by a predetermined dimension with respect to the load arm 3b on the bulk head 1b side, and the end of the load arm 3c is bolted through the spacer 4d. It is fixed to the guide arm 5 by 7.

The material of each member is the same as that of the reference example and the first embodiment.

Next, setting of the length of the load arm 3c will be described with reference to FIG.

The dimensions of each member are shown in equation (7).

_{Rs-Rd = 1.3mm, l 1} = 2.9mm, l 2 + l 3 = l 4 + l 5, l 6 = 1.6mm ... (7) linear expansion coefficient is identical to that of (2).

Thermal off-track amount when the temperature change of [Delta] T ° C. [delta] is _{δ = {(Rsα di -l 1} α t + l 2 α sa + l 3 α gu) - (Rdα di -l 6 α d + l 5 α sb + l 4 α _gu )} × ΔT (8)

To satisfy δ = 0 for all values of ΔT, the following equation (9) should be established.

_{(Rsα di -l 1 α t +} l 2 α sa + l 3 α gu) - (Rdα di -l 6 α d + l 5 α sb + l 4 α gu) = 0 ... (9) (7), equation (9) Considering this, thin film head 1a with δ = 0
Side load arm 3c and bulkhead 1b side load arm
When the difference in length from 3b (l ₂ -l ₅ ) is calculated, it becomes as follows.

Therefore, if the load arm 3c, which is 3.8 mm longer in the track width direction than the load arm 3b on the bulkhead 1b side, is used to support the thin film head 1a, the thermal off-track amount is always 0 even if the temperature changes. be able to.

In the present embodiment and the first embodiment, the thermal off-track amount can always be set to 0, so that the temperature application range is widened even in the magnetic disk device having the magnetic head having different core positions in the track width direction. be able to.

Next, a third embodiment of the present invention will be described with reference to FIG.

This embodiment is structurally the same as that of the reference example, but the amount of thermal off-track is made almost zero by appropriately selecting the material.

The material settings of the load arm 3a on the thin film head 1a side and the load arm 3d on the bulk head 1b side will be described.

The thermal off-track amount δ in the head assembly 20d that is structurally the same as the reference example is δ = {(Rsα _di −l _{1 if} the amounts other than the load arms 3a and 3b are the same as those in the equation (2). _{α t + l 2 α sa +} l 3 α gu) - (Rdα di -l 6 α d + l 5 α sb + l 4 α gu)} × ΔT ... (1) and represented.

To satisfy δ = 0 for all values of ΔT, the following equation (10) should be established.

_{(Rsα di -l 1 α t +} l 2 α sa + l 3 α gu) - (Rdα di -l 6 α d + l 5 α sb + l 4 α gu) = 0 ... (10) (2), the expression (10) Considering this, thin film head 1a with δ = 0
Side load arm 3c and bulkhead 1b side load arm
The difference (α _sa −α _sb ) in the coefficient of linear expansion from 3d is as follows.

Therefore, the difference in the linear expansion coefficient between the load arm 3c on the thin film head 1a side and the load arm 3d on the bulk head 1b side (α _sa
If a material having a value of −α _sb ) as described above is used, the thermal off-track amount can always be 0 even if the temperature changes.

In this example, since SUS304 was used for the load arm 3a and SUS316 was used for the load arm 3d, the linear expansion coefficient of them was α _sa = 16.5 × 10 ^-6 ° C ^-1 α _sb = 15.9 × 10 ^-6 ° C. ^Since it is ⁻¹ , α _sa −α _sb = 0.6 × 10 ⁻⁶ ° C. ⁻¹ , and the thermal off-track amount can be reduced by 60% compared with the head assembly of the reference example.

A fourth embodiment of the present invention will be described with reference to FIG.

The thin film head 1a is generally provided with two cores 22a and 22c in view of the yield at the time of manufacturing, but in this embodiment, the core 22c closer to the spindle 9 is set to be capable of reading data. The other parts have the same structure as that of the reference example.

The thermal off-track amount in this embodiment is calculated.

The coefficient of linear expansion is the same as in equation (2), and the dimensions are shown in equation (11).

_{Rs-Rd = -1.3mm, l 1} = 0.3, the _{l 2 = l 5 = 25mm,} l 3 = l 4, l 6 = 1.6mm ... (11) thermal off-track amount δ in this case, (3) Similarly, δ = {(Rs−Rd) α _di −l ₁ α _t + l ₆ α _d } ΔT = (− 1.3 × 23.5 × 10 ⁻⁶ −0.3 × 7.8 × 10 ⁻⁶ + 1.6 × 10.8 × 10 ⁻⁶ ) × 40 = −0.62 × 10 ⁻³ mm = −0.62 μm.

In this embodiment, the thermal off-track amount δ can be reduced by about 40% as compared with the reference example.

Although the four embodiments have been described in detail above, it is apparent that the thermal off-track amount can be reduced to zero or reduced even when the various embodiments are combined.

Further, in the above-mentioned various embodiments, since an inexpensive bulk head made of a ferrite material is used for the data head and a thin film head is used for the servo head which operates simultaneously with the bulk head, mutual signal Without interference of
The distance between the data head and the servo head can be narrowed, the magnetic disk device can be downsized, and both the data head and the servo head are thin film heads. Therefore, the cost can be reduced.

EFFECTS OF THE INVENTION According to the present invention, in a magnetic disk device having magnetic heads having different core positions in the track width direction, a compensating member, a supporting member having a length or a linear expansion coefficient appropriately set, and the like are provided. Therefore, even if the temperature of the magnetic disk device changes, the thermal off-track amount can be reduced, and the information can be reliably read.

Further, since the amount of thermal off-track can be made small and the thin film head and the bulk head can be mixed, the distance between the heads can be made narrower, the size can be reduced, and the thin film head can be used as a whole. Therefore, it is possible to reduce the cost.

[Brief description of drawings]

1 to 5 show a first embodiment. FIG. 1 is a front view of a head assembly, FIG. 2 is a side view of the head assembly, and FIG. Partial sectional view, FIG. 4 is a sectional view of a magnetic disk device, FIG. 5 is an explanatory view for explaining thermal off-track, and FIGS. 6 to 8 show a second embodiment. The figure shows the side view of the head assembly, No. 7.
FIG. 8 is a sectional view of a main part of the head assembly, FIG. 8 is an explanatory view for explaining thermal off-track, and FIG. 9 is an explanatory view for explaining thermal off-track of the third embodiment.
FIG. 10 is an explanatory view for explaining the fourth embodiment, and FIGS.
FIG. 13 shows a reference example, FIG. 11 is a side view of the head assembly, FIG. 12 is a sectional view of a main part of the head assembly, and FIG. 13 is an explanatory view for explaining thermal off-track. is there. 1a, 1c …… thin film head, 1b …… bulkhead, 2 …… gimbal, 3a, 3b, 3c, 3d …… load arm, 4a, 4b …… spacer, 4c …… compensating spacer (compensating member), 5 …… Guide arm, 6 …… FPC, 7 …… Bolt, 8a …… Servo magnetic disk, 8b …… Data magnetic disk, 9 …… Spindle, 11 …… Carriage, 12 …… Bearing, 13…
… Guide rails, 17 …… covers, 20a, 20b, 20c, 20d ……
Head assembly.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Takahashi 2880 Kokuzu, Odawara, Kanagawa Stock company Hitachi Ltd. Odawara factory (72) Inventor Atsushi Naruse 2880, Kokuzu, Odawara, Kanagawa Hitachi Odawara factory (72) Inventor Kawakami ▲ Syu ▼ 2880 Kokufu, Odawara-shi, Kanagawa Hitachi Ltd. Odawara Plant (72) Inventor Shoichi Setone 2880, Kokuzu, Odawara, Kanagawa Hitachi Ltd. Odawara Plant ( 72) Inventor Hiroshi Daito 2880, Kozu, Odawara-shi, Kanagawa Stock company Hitachi Ltd. Odawara factory (56) Reference JP 63-244378 (JP, A) JP 63-317991 (JP, A) JP 56-11663 (JP, A) JP-A-63-136365 (JP, A)

Claims (4)

[Claims] 1. A plurality of magnetic disks and a plurality of magnetic heads respectively provided for the plurality of magnetic disks, wherein at least one of the plurality of magnetic heads is a thin film magnetic head and the rest are bulk. In a magnetic disk device that is a magnetic head, of the thin film magnetic head and the bulk magnetic head,
Between the support member that supports one magnetic head and the member that is joined to the support member, the core of the one magnetic head due to thermal expansion and the distance in the track width direction between the magnetic disk and the one magnetic head are provided. A magnetic disk device comprising a compensating member for compensating for a difference between a change and a change in a track width direction distance between the core of the other magnetic head and the magnetic disk with respect to the other magnetic head due to thermal expansion. . 2. A plurality of magnetic disks and a plurality of magnetic heads respectively provided for the plurality of magnetic disks, at least one of the plurality of magnetic heads being a thin film magnetic head, and the rest being bulk. In a magnetic disk device that is a magnetic head, of the thin film magnetic head and the bulk magnetic head,
A change in the track width direction distance between the magnetic disk and the core of the one magnetic head supporting one magnetic head due to thermal expansion, and the core of the other magnetic head due to thermal expansion and the other 2. A magnetic disk drive, comprising: a supporting member whose length is set so as to be able to compensate for a difference between the magnetic head and the magnetic disk and a change in the distance in the track width direction. 3. A plurality of magnetic disks, and a plurality of magnetic heads respectively provided to the plurality of magnetic disks, at least one of the plurality of magnetic heads being a thin film magnetic head, and the rest being bulk. In a magnetic disk device that is a magnetic head, of the thin film magnetic head and the bulk magnetic head,
A change in the track width direction distance between the magnetic disk and the core of the one magnetic head supporting one magnetic head due to thermal expansion, and the core of the other magnetic head due to thermal expansion and the other 2. A magnetic disk device, comprising: a support member having a linear expansion coefficient capable of compensating for a difference between the magnetic head and the magnetic disk and a change in the distance in the track width direction. 4. A magnetic disk device comprising a plurality of magnetic disks and a plurality of magnetic heads respectively provided for the plurality of magnetic disks, wherein a predetermined magnetic head among the plurality of magnetic heads is The magnetic head has two or more cores in the track width direction, and among the two or more cores of the predetermined magnetic head, the track of the core of the predetermined magnetic head due to thermal expansion and the magnetic disk for the predetermined magnetic head. Reading or writing information from the core having a smaller difference between the change in the distance in the width direction and the change in the distance in the track width direction between the core of another magnetic head and the magnetic disk with respect to the other magnetic head due to thermal expansion. A magnetic disk device characterized by being set to be possible.