Flexure chain blank sheet for disk drive suspension

A flexure chain blank sheet includes a plurality of frame units. Each of the frame units includes a frame portion, and a plurality of flexure elements arranged within the frame portion. The frame portion includes lengthwise frames extending in a longitudinal direction of the flexure elements, and lateral frames extending in a width direction of the flexure elements. A slit that extends along the lateral frames, a connection portion, and recesses are formed between adjacent frame units. An opening width of the recesses is greater than an opening width of the slit. The connection portion includes a portion-to-be-cut which is to be cut by a cutter. The recesses allow insertion of the cutter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2014-210683, filed Oct. 15, 2014, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a flexure chain blank sheet for a disk drive suspension used for manufacturing a flexure of a disk drive suspension.

2. Description of the Related Art

A hard disk drive (HDD) is used in an information processing apparatus, such as a personal computer. The hard disk drive comprises a magnetic disk rotatable about a spindle, a carriage turnable about a pivot, etc. On an arm of the carriage, a disk drive suspension (which will be hereinafter simply referred to as a suspension) is provided. The suspension comprises elements such as a load beam, and a flexure disposed to overlap the load beam. A magnetic head including a slider is mounted on a gimbal portion formed near a distal end of the flexure. The magnetic head is provided with elements for accessing data, that is, for reading and writing data. The load beam and the flexure, etc., constitute a head gimbal assembly.

Various types of flexures have been put to practical use according to the required specification. As an example of a flexure, a flexure with conductors is known. The flexure with conductors includes a metal base made of a thin stainless steel plate, an insulating layer made of an electrically insulating material, such as polyimide, which is formed on the metal base, a plurality of conductors formed on the insulating layer, etc. The flexure includes a proximal portion which overlaps the load beam, and a tail portion (a flexure tail) which extends toward the rear of a baseplate.

Conventionally, as a means for enhancing the manufacturing efficiency of the flexure, a flexure chain blank sheet disclosed in, for example, JP 5,273,271 B (Patent Literature 1) and JP 5,365,944 B (Patent Literature 2) is known. In order to manufacture the flexure chain blank sheet, a number of flexure elements having the same shape are formed by etching a stainless steel plate, for example. An example of the flexure chain blank sheet is constituted by arranging a plurality of frame units longitudinally relative to the flexure elements. Each of the frame units is constituted by a frame portion and a number of flexure elements arranged at a predetermined pitch within the frame portion.

The frame portion of the flexure chain blank sheet commonly includes a pair of lengthwise frames that agrees with the longitudinal direction (dimension) of the flexure element, and a pair of lateral frames that agrees with the lateral direction (dimension) of the flexure element. In these lengthwise frames or lateral frames, positioning holes to be used in positioning the flexure chain blank sheet in the manufacturing process of the flexure may be formed at several places. For example, when a positioning hole is formed in the lateral frame, the width of the lateral frame (the dimension which is orthogonal to the longitudinal dimension of the lateral frame) must be made greater than the outside diameter of the positioning hole. However, the greater the width of the lateral frame is, the greater the length of the flexure chain blank sheet becomes. In order to reduce the width of the lateral frame, the positioning hole may be made smaller, but in that case, the positioning pin must also be made small. Reduction in the size of the positioning pin has a limit.

Depending on an apparatus or a jig to be used in the manufacturing process of the flexure, the size (outer dimensions) of a single flexure chain blank sheet may be restricted. Accordingly, if the length of the flexure chain blank sheet is increased in even the slightest terms, the number of frame units which can be formed in a flexure chain blank sheet must be reduced by one. In one frame unit, since a number of (several tens of to several hundreds of) flexure elements which are formed by etching are arranged at a predetermined pitch, reducing the frame unit by one means reducing several tens of to several hundreds of flexures per flexure chain blank sheet. Accordingly, there arises a problem that the manufacturing efficiency of flexures is drastically reduced.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the object of the present invention is to provide a flexure chain blank sheet for a disk drive suspension which can keep the number of frame units as it is even if the length of a flexure is slightly increased by enabling the frame portion of the frame unit to be compact.

An embodiment relates to a flexure chain blank sheet for a disk drive suspension comprising a plurality of frame units, and each of the frame units comprises a frame portion made of a stainless steel plate, and a plurality of flexure elements arranged at a predetermined pitch within the frame portion. Each of the flexure elements includes a metal base formed of a stainless steel plate, which is the same material as the frame portion, and a conductive circuit portion formed on the metal base. The frame portion includes a first lengthwise frame and a second lengthwise frame extending in a longitudinal direction of the flexure elements, and a first lateral frame and a second lateral frame extending in a width direction of the flexure elements. Also, the frame portion comprises a slit which is formed between the first lateral frame of one of adjacent frame units and the second lateral frame of the other frame unit, a connection portion which connects between the first lateral frame of the one of the frame units and the second lateral frame of the other frame unit, and recesses which are formed on both sides of the connection portion. The slit has a first opening width. The connection portion includes a portion-to-be-cut which is to be sheared by a cutter. The recesses each have a second opening width greater than the first opening width, and allow the cutter to be inserted therein.

According to this embodiment, the lateral frames of the frame portions of the respective frame units which constitute a single flexure chain blank sheet can be made compact. Accordingly, even if the length of a flexure is slightly increased, the number of frame units formed on one flexure chain blank sheet can be kept as it is. Therefore, when a flexure is manufactured by using the flexure chain blank sheet, it becomes possible to use a flexure chain blank sheet including more flexure elements, and production of the flexures can be carried out efficiently.

In one embodiment, the flexure chain blank sheet comprises a first positioning hole which is formed at a place different from the connection portion of the first lateral frame, and also from the recesses. The connection portion may comprise a first connection portion and a second connection portion which are formed to be spaced apart from each other in a width direction of the frame portion, and the first positioning hole may be formed between the first connection portion and the second connection portion. The flexure elements comprise rear ends of tail portions, respectively, which are mutually connected by the first lateral frame. An example of the second lateral frame includes a distal end linking portion which connects distal end portions of the flexure elements to each other. A second positioning hole may be formed in the distal end linking portion.

DETAILED DESCRIPTION OF THE INVENTION

A flexure chain blank sheet according to one embodiment will be hereinafter described with reference toFIGS. 1 to 8.

A hard disk drive (HDD)10shown inFIG. 1comprises a case11, disks13rotatable about a spindle12, a carriage15turnable about a pivot14, and a positioning motor16for turning the carriage15. The case11is sealed by a lid (not shown).

FIG. 2is a cross-sectional view schematically showing a part of the disk drive10. The carriage15is provided with arms17. At a distal end portion of each arm17, a disk drive suspension (hereinafter simply referred to as a suspension)20is mounted. At a distal end of the suspension20, a slider21which serves as a magnetic head is provided. As each disk13rotates at high speed, an air bearing is formed between the disk13and the slider21.

If the carriage15is turned by the positioning motor16, the suspension20moves radially relative to the disk13, and the slider21thereby moves to a desired track of the disk13. The slider21is provided with a magnetic coil for recording data on the disk13, a magneto resistive (MR) element for reading data recorded on the disk13, etc. The MR element converts a magnetic signal recorded on the disk13into an electrical signal.

FIG. 3shows an example of the suspension20. The suspension20comprises a baseplate30, a load beam31, a hinge portion32, and a flexure40with conductors. The flexure40with conductors may be simply referred to as the flexure40. A boss portion30aof the baseplate30is secured to the arm17(FIGS. 1 and 2) of the carriage15.

FIG. 4shows the flexure40. The flexure40includes a proximal portion40aoverlapping the load beam31(FIG. 3), and a tail portion40bextending toward the back (i.e., in the direction indicated by arrow R inFIG. 3) of the baseplate30from the proximal portion40a. The proximal portion40aof the flexure40is secured to the load beam31by fixing means such as laser welding. A tongue41is formed near a distal end portion40cof the flexure40. The slider21(FIGS. 2 and 3) is mounted on the tongue41. A plurality of tail electrodes42are formed in the tail portion40b.

FIG. 5is a plan view showing a part of a flexure chain blank sheet50used in a process of manufacturing the flexure40.FIG. 6is a partial enlarged view of the flexure chain blank sheet50. The flexure chain blank sheet50includes a plurality of frame units511to51n. Each of these frame units511to51nincludes a frame portion60formed by etching a metal plate (for example, a stainless steel plate), and a plurality of (several tens to several hundreds of) flexure elements40′ formed at a predetermined pitch within the frame portion60. An example of the metal plate is formed of austenitic stainless steel, and an example of the thickness is 18 μm (12 to 25 μm).

The frame units511to51ninclude the frame portions60formed around the frame units511to51n, respectively, and a number of (several tens to several hundreds of) flexure elements40′ arranged at a predetermined pitch within their respective frame portions60. Each of the flexure elements40′ includes a metal base65obtained by etching the metal plate (stainless steel plate), and a conductive circuit portion66formed on the metal base65. The conductive circuit portion66includes an insulating layer formed on the metal base65, a plurality of conductors made of copper which are formed on the insulating layer, and an electrically insulating cover layer covering these conductors.

The frame portion60includes a first lengthwise frame71and a second lengthwise frame72, and a first lateral frame75and a second lateral frame76. Each of the first lengthwise frame71and the second lengthwise frame72extends longitudinally relative to the flexure element40′ (i.e., in a longitudinal direction as indicated by double-headed arrow X inFIG. 5). Each of the first lateral frame75and the second lateral frame76extends laterally relative to the flexure element40′ (i.e., in a width direction as indicated by double-headed arrow Y inFIG. 5). By these pairs of lengthwise frames71and72and lateral frames75and76, the frame portion60which is continuous all around each of the frame units is formed. In each of the frame units, rear ends40dof the tail portions40bof the flexure elements40′ are connected to each other by the first lateral frame75.

A slit80, a connection portion81, and recesses82and83are formed between the frame units511and512which are adjacent longitudinally relative to the flexure chain blank sheet50(as indicated by double-headed arrow X inFIG. 5). The slit80has a first opening width G1(FIG. 6). The slit80is formed between the first lateral frame75of the frame unit511, which is one of the adjacent frame units, and the second lateral frame76of the other frame unit512. The slit80extends longitudinally along the lateral frames75and76.

The connection portion81and the recesses82and83are formed in the first lateral frame75. The connection portion81connects the first lateral frame75of the frame unit511on one side and the second lateral frame76of the frame unit512of the other side to each other. The connection portion81is also represented as a first connection portion81aand a second connection portion81bformed to be spaced apart from each other laterally relative to the frame portion60(as indicated by double-headed arrow Y inFIG. 5). The first connection portion81aand the second connection portion81beach have a portion-to-be-cut91which is to be cut by a cutter90(FIG. 8).

Recesses82and83are formed on both sides of the first connection portion81a. Recesses82and83are also formed on both sides of the second connection portion81b. Each of these recesses82and83has a second opening width G2. The second opening width G2is greater than the first opening width G1. Moreover, the second opening width G2is greater than thickness T (FIG. 8) of the cutter90. The first opening width G1is less than thickness T of the cutter90. That is, the recesses82and83have the shape and size which allow the cutter90to be inserted therein.

Further, at positions different from where the connection portion81is formed, a plurality of circular first positioning holes100are formed in the first lateral frame75. Part of the first positioning holes100is formed between the first connection portion81aand the second connection portion81b, as shown inFIG. 5. Width W1(FIGS. 6 and 7) of the first lateral frame75is greater than the outside diameter of the first positioning hole100. Width W1in this specification refers to a width dimension which is orthogonal to the longitudinal dimension of the first lateral frame75. In the manufacturing process of the flexure40, in order to keep the flexure chain blank sheet50at a predetermined position, a first positioning pin may be inserted into the first positioning hole100.

In each of the frame units, a distal end linking portion110which connects distal end portions40cof the flexure elements40′ to each other is formed. The distal end linking portion110constitutes the second lateral frame76. In the flexure elements40′, second positioning holes120are formed, respectively, at intervals laterally relative to the frame portion60(as indicated by double-headed arrow Y inFIG. 5).

Width W2(FIGS. 6 and 7) of the second lateral frame76is greater than the outside diameter of the second positioning hole120. Width W2in this specification refers to a width dimension which is orthogonal to the longitudinal dimension of the second lateral frame76. In the manufacturing process of the flexure40, in order to keep the flexure elements40′ at predetermined positions, a second positioning pin may be inserted into the second positioning hole120.

FIG. 8shows a part of the cutter90for cutting the connection portion81, and the flexure chain blank sheet50. An example of the cutter90comprises a pair of heels130and131, and a blade132formed between the heels130and131. When the connection portion81is cut, in a state in which the heels130and131are inserted into the recesses82and83, and supported by a blade receiving jig, the connection portion81is cut (sheared) by the blade132.

The connection portion81may be cut by a one-sided-heel-type cutter90′ having a heel130on one side, as shown by the cutter90′ of another embodiment illustrated inFIG. 9. Alternatively, the connection portion81may be sheared by a cutter which does not have a heel.

The connection portion81, the recesses82and83for cutter insertion, and the positioning holes100are formed in the first lateral frame75of the frame portion60of the flexure chain blank sheet50. The connection portion81and the recesses82and83are formed at places different from where the positioning holes100are formed. The recesses82and83are shaped into such a form that they are recessed by the second opening width G2at an interior side of width W1(FIGS. 6 and 7) of the first lateral frame75.

The first opening width G1of the slit80formed in the flexure chain blank sheet50is less than thickness T (FIG. 8) of the cutter90. However, since the recesses82and83having the second opening width G2are formed on both sides of the connection portion81, the space to allow the heels130and131of the cutter90to be inserted can be secured by the recesses82and83. Moreover, a cutting allowance to be cut by the blade132of the cutter90can be secured by the connection portion81between the recesses82and83.

In contrast, in a conventional flexure chain blank sheet, a slit having an opening width greater than the thickness of a cutter and a connection portion are formed alternately along the entire length of space between a pair of adjacent lateral frames. Further, by inserting the cutter into the slits, the connection portions are cut. When a lateral frame has the positioning holes, there is a limit on reducing the width of the lateral frame (the dimension which is orthogonal to the longitudinal dimension of the lateral frame). Accordingly, the greater the opening width of the slit is, the greater the outer dimensions (in particular, the length) of the flexure chain blank sheet becomes.

Depending on an apparatus or a jig to be used in the manufacturing process of the flexure, the size (outer dimensions) of a single flexure chain blank sheet may be restricted. In that case, once the length of the flexure chain blank sheet exceeds a permissible value if only a little, the number of frame units which can be formed in a flexure chain blank sheet must be reduced by one. In one frame unit, several tens of to several hundreds of flexure elements formed by etching are arranged at a predetermined pitch. Accordingly, reducing the frame unit by one means reducing several tens of to several hundreds of flexures per flexure chain blank sheet. Accordingly, there arises a problem that the manufacturing efficiency of flexures is drastically reduced.

However, according to the flexure chain blank sheet50of the present embodiment, even if the length of the flexure element is slightly increased according to the change in the specification of the flexure, it is possible to secure the same number of frame units as the conventional frame units within an allowable dimension of a single flexure chain blank sheet50. That is, it is possible to prevent the number of flexure elements40′ formed on a single flexure chain blank sheet from being reduced. It is possible to form as many flexure elements40′ as possible on a single flexure chain blank sheet50, and flexure40can be manufactured efficiently.

Also, needless to say, in carrying out the present invention, as well as the specific shape of the flexure and flexure element, each of the elements which constitute the flexure chain blank sheet may be modified variously, such as modifying the number and arrangement of the frame unit and flexure element, and the shape of the slit, connection portion, and recess. Also, a plurality of frame units may be formed in a row not only longitudinally but also laterally relative to the flexure chain blank sheet.