magnetic disk drive

Abstract

The object of the present invention is to provide a magnetic disk drive that has excellent performance in removing gas molecules having a predetermined effective diameter. [Solution] The magnetic disk device of the embodiment has a housing, a rotatable disk provided inside the housing, a head provided inside the housing that can write and read information to the disk, a voice coil motor provided inside the housing that drives the head, and a filter structure provided inside the housing that has a porous body including a first porous body having an average pore diameter of 0.4 nm or more and 1.0 nm or less.

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a magnetic disk drive. [Background technology]

[0002] A hard disk drive (HDD) is equipped with a magnetic disk that rotates at high speed and a head that reads and writes information from the magnetic disk. If a large amount of gas molecules exist inside the HDD housing, it may become difficult to control the distance between the head and the disk, which may shorten the lifespan of the HDD. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 1,163,1436 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to provide a magnetic disk drive that has excellent performance in removing gas molecules having a predetermined effective diameter. [Means for solving the problem]

[0005] The magnetic disk device of the embodiment has a housing, a rotatable disk provided inside the housing, a head provided inside the housing that can write and read information to the disk, a voice coil motor provided inside the housing that drives the head, and a filter structure provided inside the housing that has a porous body including a first porous body having an average pore diameter of 0.4 nm or more and 1.0 nm or less. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a perspective view showing a magnetic disk device according to a first embodiment. [Figure 2] FIG. 1 is a schematic plan view showing a magnetic disk device according to a first embodiment. [Figure 3] FIG. 10 is a schematic plan view showing a modified example of the magnetic disk device according to the first embodiment. [Figure 4] FIG. 3 is a top view showing an example of the structure of a first filter. [Figure 5] FIG. 3 is a perspective view showing an example of the structure of a first filter. [Figure 6] FIG. 3 is a schematic plan view showing an example of the structure of a first filter. [Figure 7] FIG. 10 is a schematic cross-sectional view showing a magnetic disk drive according to a second embodiment. [Figure 8] FIG. 4 is a diagram illustrating an example of the structure of a second filter. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0008] The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Furthermore, even when the same part is shown, the dimensions and ratios may be different depending on the drawing.

[0009] In the present specification and the drawings, elements similar to those described above with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0010] For the sake of explanation, the direction from the base 11 of the housing 10 to the top cover 12 will be referred to as "up," and the direction from the top cover 12 to the base 11 will be referred to as "down." However, the "up" and "down" directions are not limited to the direction of gravity or the directions when the magnetic disk drive is installed.

[0011] (First embodiment) FIG. 1 is a perspective view showing a magnetic disk device 100 according to this embodiment.

[0012] The magnetic disk drive 100 has a housing 10, which has a box-shaped base 11 and a top cover 12. The base has a bottom surface 11b and a side surface 11w that rises along the edge of the bottom surface 11b and is integrally formed with the bottom surface 11b. The housing 10 is sealed by combining the top cover 12 with the base 11 using a plurality of connecting parts. For example, the connecting parts may be screws or the like, or an adhesive or a fitting mechanism may also be used. FIG. 1 shows an example in which the housing 10 is connected using a plurality of screws 13. Possible materials for the base 11 and the top cover 12 include, for example, a metal containing Al or Fe.

[0013] The base 11 is provided with a disk 20 for recording data, a spindle motor 21, and an actuator 30. The spindle motor 21 holds the disk 20 so that it can rotate. The actuator 30 also has a head 31 that scans the surface of the disk 20 and reads and writes information. The actuator 30 also has an arm 32 to which the head 31 is attached, and a voice coil motor 33 that controls the position of the arm 32.

[0014] A substrate 40 is provided on the base 11. The substrate 40 is electrically connected to the actuator 30 via an FPC (Flexible Printed Circuit) substrate 41. The substrate 40 controls the operations of the head 31 and the voice coil motor 33.

[0015] A plurality of disks 20 may be mounted on the spindle motor 21. For example, two, three, or four disks may be mounted, or five or more disks may be mounted.

[0016] A first filter 51 is provided on the base 11 and in the vicinity of the disk 20. The first filter 51 is provided at a position through which at least a portion of the airflow generated by the rotation of the disk 20 passes. The first filter 51 includes a porous body PM. Details of the porous body PM will be described later.

[0017] Furthermore, a hole 12h may be provided in the top cover 12. A second filter 52 may be further provided inside the housing 10 at a position corresponding to the hole 12h. The second filter 52 will be described later with reference to FIGS.

[0018] FIG. 2 is a plan view of the magnetic disk device 100 shown in FIG.

[0019] A first filter 51 is provided on the base 11. FIG. 2 illustrates an example in which the base 11 has four corners. FIGS. 1 and 2 illustrate an example in which the first filter 51 is disposed between a first corner 11c1 of the base 11 and the disk 20. The corner is a portion of the side surface 11w of the base 11 that has a curvature. The first corner 11c1 is one of the corners located on the opposite side of the disk 20 from the actuator 30 or the substrate 40. In the X direction, the disk 20 is located between the first corner 11c1 and the actuator 30 or the substrate 40.

[0020] FIG. 3 illustrates an example of a modification of the magnetic disk device 100 according to the first embodiment, in which the first filter 51 is provided between the disk 20 and the actuator 30. Of the multiple corners of the base 11, the corner closest to the actuator 30 is referred to as the second corner 11c2. FIG. 3 illustrates an example in which the first filter 51 is provided near the second corner 11c2. Near means closer than the other corners.

[0021] Furthermore, the first filter 51 may be provided, for example, between the disk 20 and the substrate 40. The first filter 51 may be provided near any of the multiple corners of the base 11.

[0022] In both the cases of FIG. 2 and FIG. 3, the first filter 51 is provided on the side of the disk 20, and the airflow generated around the disk 20 passes through at least a part of the first filter 51.

[0023] Next, an example of the structure of the first filter 51 will be described with reference to FIGS.

[0024] FIG. 4 is a plan view showing an example of a structure for holding the porous body PM included in the first filter 51. As shown in FIG.

[0025] The first filter 51 has a surrounding body 60 that covers the porous body PM. In Fig. 4, the porous body PM is not exposed, but is surrounded and held by the surrounding body 60. The surrounding body 60 is made of a breathable material. The surrounding body 60 includes, for example, a nonwoven fabric.

[0026] 5 is a perspective view of the enclosure 60 shown in FIG. 4. The enclosure 60 contains a porous body PM, and the periphery is sealed to surround the porous body PM. An airflow passing through the porous body PM flows from the first main surface 60a of the enclosure 60 toward the second main surface 60b opposite the first main surface 60a, or in the opposite direction. The porous body PM adsorbs and removes gas molecules and the like contained in the airflow.

[0027] In order to reduce resistance when air flows through the enclosure 60 , it is desirable that the first main surface 60 a or the second main surface 60 b of the enclosure 60 be oriented in a direction facing the disk 20 .

[0028] The structure for fixing the enclosure 60 included in the first filter 51 to the base 11 may be, for example, by fitting it into a part having a recess, or may be a structure in which the enclosure 60 is sandwiched.

[0029] Furthermore, it is desirable that the first filter 51 has a mechanism for controlling the flow path of the airflow. FIG. 6 is a diagram schematically illustrating an enclosure 60 and an airflow control unit 62 provided in the first filter 51. The structure of the first filter 51 provided on the side of the disk 20 is shown. The first filter 51 has an enclosure 60 containing a porous material PM, and an airflow control unit 62 provided upstream of the enclosure 60 in the direction of the airflow generated by the rotation of the disk 20. FIG. 6 shows an example in which the first main surface 60a of the enclosure 60 is provided in a direction facing the disk 20. At least a portion of the airflow control unit 62 is provided farther from the disk 20 than the enclosure 60.

[0030] The airflow control section 62 has a curved surface 62c. At least a portion of the curved surface 62c is formed along an arc. Here, the arc may be a circular arc or an elliptical arc. For example, the curved surface 62c is formed along a circle of curvature Cc having a predetermined radius of curvature. The center of curvature Oc of the circle of curvature Cc is located in the same direction as the direction in which the disk 20 is placed relative to the airflow control section 62. In other words, the curved surface 62c is curved in the same direction as the arc that is the shape of the edge of the circular disk 20.

[0031] The porous body PM provided in the first filter 51 includes at least a first porous body. The average diameter of the pores of the first porous body is preferably smaller than the average diameter of the pores of the activated carbon or silica gel. Here, the average diameter of the pores is obtained by measuring the diameters of at least two or more pores and taking the average. Alternatively, it may be the median or mode of the diameters measured for at least two or more pores. The average diameter of the pores of the activated carbon or silica gel is, for example, greater than 1.0 nm.

[0032] The first porous body has an average pore diameter of, for example, 0.4 nm to 1.0 nm. To adsorb gas molecules with an effective diameter of, for example, 0.4 to 0.7 nm, the average pore diameter is preferably 0.7 nm to 1.0 nm. Here, the effective diameter of gas molecules is estimated as the substantial diameter when gas molecules collide with each other, assuming a spherical shape.

[0033] The first porous body is, for example, a porous body containing zeolite. Hereinafter, the term "zeolite" includes synthetic zeolite. The first porous body is, for example, a zeolite belonging to the skeleton code FAU. The first porous body is, for example, an X-type zeolite. The first porous body is, for example, a 13X-type zeolite.

[0034] Furthermore, the first filter 51 may contain activated carbon in addition to the first porous body, or may contain silica gel.

[0035] The first filter 51 may have a second porous body P2 in addition to the first porous body. The second porous body has an average pore diameter of, for example, 0.1 nm or more and 0.4 nm or less. Preferably, it may be 0.2 nm or more and 0.4 nm or less. The second porous body is, for example, a porous body containing zeolite. The second porous body is, for example, a zeolite belonging to the skeletal code LTA. The second porous body is, for example, an A-type zeolite. The second porous body is, for example, a 3A-type zeolite.

[0036] The operation of the magnetic disk device 100 will now be described.

[0037] The disk 20 is rotated by the spindle motor 21. Based on a signal transmitted from the substrate 40, the voice coil motor 33 is driven to control the position of the head 31 relative to the rotating disk 20. The magnetic disk device 100 operates by writing or reading magnetic information at various positions on the disk 20 while changing the position of the head 31 in various ways.

[0038] The rotation of the disk 20 causes an air flow around the disk 20. Here, the air is not limited to air with the same composition as the atmosphere, but may contain various types of gas molecules. The air flow on the surface of the disk 20 controls the distance between the disk 20 and the head 31.

[0039] Meanwhile, a circular air flow also occurs on the side of the disk 20. The first filter 51 is located on the side of the disk 20, and at least a portion of the air flowing around the disk 20 passes through the first filter 51. As the air passes through the first filter 51, gas molecules having an effective diameter of a predetermined size are adsorbed by the porous body PM.

[0040] An example of the flow path of the airflow passing through the first filter 51 will be described with reference to Figure 6. As the disk 20 rotates, an airflow AF0 flows into the first filter 51. At least a portion of the airflow AF0 flows along the airflow control section 62 as an airflow AF1. At least a portion of the airflow AF0 may flow on the side of the first main surface 60a of the enclosure 60, as shown as an airflow AF2.

[0041] The direction of the airflow AF1 changes along the curved surface 62c of the airflow control section 62. The angle at which the airflow AF1 flows into the second main surface 60b of the enclosure 60 is controlled by the shape of the curved surface 62c of the airflow control section 62. As the airflow AF1 passes through the enclosure 60 in the direction from the second main surface 60b to the first main surface 60a, the porous body PM contained in the enclosure 60 adsorbs gas molecules contained in the airflow.

[0042] It is known that gas molecules with an effective diameter of 1.0 nm or less are difficult to remove using activated carbon or silica gel because the average pore diameter is large. Furthermore, the greater the viscosity of the gas molecules, the more difficult they are to remove when they adhere to a disk or other surface. The higher the boiling point of the gas molecules, the less volatile they are, making them more difficult to desorb by heat. When using only activated carbon or silica gel, there is a risk that gas molecules with an effective diameter of 1.0 nm or less, as well as high viscosity and boiling point, could shorten the lifespan of magnetic disk drives.

[0043] Examples of gas molecules with an effective diameter of 1.0 nm or less include glycol ethers and glycol esters. Glycol ethers and glycol esters have larger molecular weights and stronger intermolecular forces than, for example, ethanol. Because glycol ethers and glycol esters have higher viscosities and boiling points than ethanol, they have been found to be more difficult to remove when attached to a disk or the like.

[0044] Examples of glycol ethers include ethylene glycol monomethyl ether (2-methoxyethanol), diethylene glycol monomethyl ether (2-(2-methoxyethoxy)ethanol), ethylene glycol monoethyl ether (2-ethoxyethanol), diethylene glycol monoethyl ether (2-(2-ethoxyethoxy)ethanol), ethylene glycol monobutyl ether (2-butoxyethanol), diethylene glycol monobutyl ether (2-(2-butoxyethoxy)ethanol), propylene glycol monomethyl ether (1-methoxy-2-propanol), and dipropylene glycol monomethyl ether ((2-methoxymethylethoxy)propanol). Examples of glycol ethers include those with an effective diameter of 0.4 nm or more and 0.7 nm or less.

[0045] The glycol ether may include those having a boiling point of 120° C. or higher and 240° C. or lower. Included are glycol ethers having a boiling point higher than that of alcohols such as ethanol.

[0046] The glycol ether may have a viscosity of 4 cP or more and 8 cP or less at room temperature and normal pressure. Included are glycol ethers with a higher viscosity than alcohols such as ethanol.

[0047] Examples of glycol esters include ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate. Examples of glycol esters include those having an effective diameter of 0.4 nm or more and 0.7 nm or less.

[0048] The glycol ester may include those having a boiling point of 120° C. or higher and 240° C. or lower. Included are glycol esters having a boiling point higher than that of alcohols such as ethanol.

[0049] The glycol ester may have a viscosity of 4 cP or more and 8 cP or less at room temperature and normal pressure. Included are glycol esters with a higher viscosity than alcohols such as ethanol.

[0050] According to the magnetic disk drive 100 of this embodiment, the porous body PM including the first porous body provided in the first filter 51 has excellent performance in adsorbing predetermined contaminants, as will be described later, and the life of the magnetic disk drive can be extended. The first porous body has pores with an average diameter of, for example, 0.4 nm or more and 1.0 nm or less, and has excellent performance in adsorbing and removing gas molecules with an effective diameter of 1.0 nm or less. For example, it has excellent performance in removing glycol ethers and glycol esters. Contamination inside the housing 10 can be suppressed, and the life of the magnetic disk drive 100 can be extended.

[0051] Glycol ethers and glycol esters, which have higher boiling points and viscosities than alcohols such as ethanol, tend to adhere to HDDs and are difficult to remove, potentially shortening the lifespan of the HDD. The magnetic disk drive 100 according to this embodiment has excellent performance in removing gas molecules, including glycol ethers and glycol esters, with an effective diameter of 1.0 nm or less, thereby extending the lifespan of the magnetic disk drive 100.

[0052] Furthermore, it is desirable that the porous body PM provided in the first filter 51 contains activated carbon in addition to the first porous body. The activated carbon can adsorb molecules of a size that the first porous body cannot adsorb, for example, molecules with an effective diameter of greater than 1.0 nm. This makes it possible to remove a wider variety of contaminants and extend the life of the magnetic disk drive 100. The activated carbon may be substituted with, for example, silica gel.

[0053] By setting the average pore diameter of the first porous body to 1.0 nm or less, the first porous body can improve the efficiency of adsorption by mainly targeting gas molecules that are too small for activated carbon or the like to adsorb. By preventing gas molecules large enough for activated carbon or the like from occupying the adsorption sites of the first porous body, the first porous body can adsorb more small gas molecules that activated carbon or the like cannot adsorb. Therefore, compared to when the average pore diameter of the first porous body is larger, gas molecules with an effective diameter of, for example, 0.4 nm or more and 0.7 nm or less can be adsorbed more efficiently.

[0054] The porous body PM provided in the first filter 51 may further include a second porous body. The second porous body has pores with an average diameter of, for example, 0.2 nm or more and 0.4 nm or less, and has a better ability to adsorb water molecules than the first porous body. Therefore, the humidity inside the housing 10 can be further reduced.

[0055] Furthermore, by providing the first filter 51 on the side of the disk 20, it is possible to efficiently adsorb gas molecules contained in the airflow that is generated on the side of the disk 20 as the disk 20 rotates. Furthermore, if the spindle motor 21 that rotates the disk 20 is a source of gas molecules, providing the first filter 51 near the source of generation can efficiently remove the gas molecules.

[0056] When a source of gas molecules is identified inside the housing 10, the gas molecules can be efficiently removed by providing the first filter 51 near the source of the gas molecules.

[0057] Furthermore, by orienting the first main surface 60a or the second main surface 60b of the enclosure 60 included in the first filter 51 toward the disk 20, it is possible to reduce resistance when the airflow passes through and reduce the effect on the rotation of the disk 20. By reducing the air resistance caused by the enclosure 60, it is possible to suppress a decrease in the rotation speed of the disk 20.

[0058] Furthermore, by orienting the first main surface 60a or the second main surface 60b of the enclosure 60 toward the disk 20, the flow path passing through the porous body PM can be lengthened, improving the efficiency of removing gas molecules compared to when the airflow flows perpendicular to the first main surface 60a or the second main surface 60b.

[0059] Furthermore, the first filter 51 may have an airflow control unit 62, as shown in FIG. 6, which controls the airflow AF1 so that the airflow AF1 flows into the second main surface 60b of the enclosure 60 at an angle smaller than 90 degrees. The airflow control unit 62 can control the angle of the airflow AF1 flowing into the second main surface 60b. The shallower the angle at which the airflow AF1 flows into the second main surface 60b, the longer the length over which the airflow AF1 passes through the enclosure 60. This further increases the efficiency with which the porous body PM contained in the enclosure 60 removes gas molecules.

[0060] Furthermore, the center of curvature Oc of the curved surface 62c of the airflow control section 62 is located in the same direction as the direction in which the disc 20 is placed relative to the airflow control section 62, and by gradually changing the direction of the airflow AF1 and directing it toward the second main surface 60b, the air resistance caused by the airflow control section 62 can be reduced.

[0061] (Second embodiment) FIG. 7 is a schematic cross-sectional view showing a magnetic disk device 200 according to the second embodiment.

[0062] The magnetic disk device 200 includes a disk 20, a spindle motor 21, and an actuator 30 inside a housing 10. The actuator 30 includes a head 31 and an arm 32.

[0063] Furthermore, a hole 12h is provided in the top cover 12 of the housing 10. The hole 12h is not limited to being circular, but may also be rectangular, elliptical, or oblong. Furthermore, the hole 12h is not limited to being provided above the disk 20, and may be located above the substrate 40 or above the actuator 30, as illustrated in FIG. 1 showing the semiconductor device 1 according to the first embodiment.

[0064] A second filter 52 is provided on the inner wall of the housing 10 in an area covering the hole 12h. The upper surface of the second filter 52 (the surface facing the base 11 is the lower surface) is in contact with the inner wall of the housing 10. The second filter 52 is provided with a porous body PM including a first porous body. Note that the porous body PM may further include at least one of activated carbon, silica gel, and a second porous body.

[0065] 8 is a schematic diagram showing an example of the structure of the second filter 52. The second filter 52 has a frame 70 having a hollow portion 70v, a porous body PM provided in the hollow portion 70v of the frame 70, and an air-permeable membrane 80 provided on the lower surface of the frame 70 at the opening of the hollow portion 70v.

[0066] The frame 70 has a hole 70h on its upper surface. The hole 70h is provided at a position corresponding to the hole 12h shown in Figure 7. The hole 70h may have a shape similar to that of the hole 12h. Alternatively, the hole 70h may have the same shape as the hole 12h.

[0067] The porous body PM including the first porous body is covered by the frame 70 from above and on the sides, and is covered by the gas permeable membrane 80 at least in part from below.

[0068] The second filter 52 may further include a mechanism for controlling the airflow that flows between the holes 70h and the porous body PM.

[0069] The frame 70 includes, for example, a plastic resin. The breathable membrane 80 is a breathable membrane, and includes, for example, a nonwoven fabric. The porous body PM provided in the second filter 52 may include at least one of activated carbon, silica gel, and a second porous body in addition to the first porous body.

[0070] The magnetic disk drive 200 according to this embodiment can seal a predetermined gas inside the housing 10 and efficiently remove gas molecules with an effective diameter of 1.0 nm or less. For example, when He is sealed inside the housing 10, He is sufficiently smaller than the average diameter of the pores of the first porous body and can pass through without being adsorbed, so the inside of the housing 10 is filled mainly with He. On the other hand, the first porous body can remove gas molecules with an effective diameter larger than He, such as glycol ethers and glycol esters. Therefore, the concentration of gas molecules with high viscosity and boiling points inside the housing 10 can be reduced, thereby extending the life of the HDD.

[0071] First, the second filter 52 and the hole 12h will be described. First, as an example, a case where He is sealed inside the housing will be described. Generally, sealing He reduces the air resistance caused by gas molecules inside the housing and can suppress the up and down movement of the head.

[0072] When He is injected from the outside of the housing 10 into the inside of the housing 10 through the hole 12h, there is a risk that other types of gas molecules may be mixed in at the same time. By providing the second filter 52 having the porous body PM including the first porous body in the flow path of the gas molecules that are sealed in the housing 10 from the outside, it is possible to prevent other types of gas molecules from being mixed in when He is sealed in.

[0073] As in the first embodiment, the first porous body has pores with an average diameter of, for example, 0.4 nm to 1.0 nm. Therefore, it has excellent performance in adsorbing gas molecules with an effective diameter of 1.0 nm or less. Furthermore, when the average pore diameter is 0.7 nm to 1.0 nm, the intrusion of gas molecules with an effective diameter of approximately 0.4 nm to 0.7 nm can be further suppressed. For example, the intrusion of glycol ethers, glycol esters, etc. can be suppressed.

[0074] Furthermore, even when air is present inside the housing 10, the gas molecules adsorbed in the porous body PM of the second filter 52 are discharged through the hole 70h and the hole 12h to the outside of the housing 10, enabling the second filter 52 to further adsorb pollutants.

[0075] The above describes an example in which the second filter 52 is provided so as to contact the top cover 12. The position at which the second filter 52 is provided is not limited to a position in contact with the top cover 12, and various arrangements are possible in a position in contact with the inner wall of the housing 10. However, the opening of the cavity 70v and the ventilation membrane 80 are provided on the surface opposite to the surface in contact with the inner wall of the housing 10.

[0076] Naturally, the magnetic disk drive may have both the first filter 51 described in the first embodiment and the second filter 52 described in this embodiment. By having both the first filter 51 and the second filter 52, it is possible to further improve the performance of removing predetermined gas molecules.

[0077] According to at least one of the first and second embodiments of the semiconductor device described above, by having a filter structure including the first filter 51 or the second filter 52 having the porous body PM including the first porous body, it is possible to provide a magnetic disk drive having an effective diameter of 1.0 nm or less and excellent performance in removing molecules with high viscosity and boiling point, such as glycol ethers and glycol esters, and to extend the life of the magnetic disk drive.

[0078] The above describes the embodiments with reference to specific examples. However, the embodiments are not limited to these specific examples. In other words, designs that are appropriately modified by a person skilled in the art from these specific examples are also included within the scope of the embodiments as long as they have the characteristics of the embodiments. The elements, as well as their arrangement, materials, conditions, shapes, diameters, etc., of the above-described specific examples are not limited to those exemplified and can be modified as appropriate.

[0079] Furthermore, the elements of each of the above-described embodiments can be combined to the extent technically possible, and combinations of these are also included within the scope of the embodiments as long as they include the features of the embodiments. In addition, within the scope of the concept of the embodiments, a person skilled in the art may conceive of various modifications and alterations, and it is understood that these modifications and alterations also fall within the scope of the embodiments.

[0080] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0081] 100, 200... Magnetic disk drive 10. Housing 11...Base 11c1...1st corner 11c2...Second corner 12 Top cover 12h...hole 13 Screw 20 disks 21. Spindle motor 30 Actuator 31...head 32 Arm 33 Voice coil motor 40... board 41...FPC board 51 First filter 52 Second filter 60 Enclosure 60a...First principal surface 60b...2nd main surface 62 Airflow control section 62c...Curved surface PM...Porous body 70...Frame body 70h...hole 80....Ventilated membrane

Claims

1. The housing and a rotatable disk disposed inside the housing; a head provided inside the housing and capable of writing and reading information to and from the disk; a filter structure provided inside the housing and having a first porous body with an average pore diameter of 0.4 nm or more and 1.0 nm or less; A magnetic disk device having:

2. The first porous body is a zeolite belonging to the skeleton code FAU.

2. The magnetic disk drive according to claim 1.

3. The filter structure further comprises activated carbon.

3. The magnetic disk drive according to claim 2.

4. The filter structure further comprises silica gel.

3. The magnetic disk drive according to claim 2.

5. The filter structure further includes a second porous body containing a zeolite having an average pore diameter of 0.2 nm or more and 0.4 nm or less and belonging to the skeleton code LTA.

5. The magnetic disk drive according to claim 1.

6. the first porous body has pores that adsorb at least one glycol ether or glycol ester having a viscosity of 4 cP or more and 8 cP or less; 5. The magnetic disk drive according to claim 1.

7. the first porous body has pores capable of adsorbing at least one glycol ether or glycol ester having a boiling point of 120°C or higher and 240°C or lower; 5. The magnetic disk drive according to claim 1.

8. The glycol ether includes at least one molecule selected from ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether.

7. The magnetic disk drive according to claim 6.

9. The glycol ether has an effective diameter of 0.4 nm or more and 0.7 nm or less.

9. The magnetic disk drive according to claim 8.

10. The filter structure further includes an enclosure covering the first porous body and provided on a side of the disk.

5. The magnetic disk drive according to claim 1.

11. the filter structure further includes an airflow control portion that is provided upstream of the first porous body in the airflow flowing through the filter structure and has a curved surface whose center of curvature is located in the same direction as the direction in which the disk is provided.

11. The magnetic disk drive according to claim 10.

12. an upper surface of the filter structure contacting an inner wall of the housing; a frame body having a hollow portion; a ventilation membrane provided on the lower surface of the frame body at the opening of the hollow portion; and The first porous body is provided in the hollow portion of the frame body.

5. The magnetic disk drive according to claim 1.

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