JP4579099B2 - Magnetic tape take-up reel, method of manufacturing the same, and tape cartridge - Google Patents

Description

  The present invention relates to a magnetic tape take-up reel, a method for manufacturing the same, and a tape cartridge using the magnetic tape take-up reel.

  In recent years, means for transmitting information at high speed, such as an optical fiber, has remarkably developed, and an information recording medium capable of recording / reproducing the data has been required while transferring a large amount of data. Examples of the information recording medium include a flexible disk, a magnetic drum, a hard disk, and a magnetic tape cartridge with a built-in magnetic tape. Among them, the magnetic tape cartridge has a large recording capacity per volume, so that information recording for data backup is possible. Widely used as a medium.

  The magnetic tape is usually used in a state of being wound around a reel and housed in a cartridge. As shown in FIG. 10, the reel 100 is welded and fixed to the hub portion 400, for example, a hub portion 400 on which a magnetic tape can be wound, a disc-shaped first flange 300 integrally formed with the hub portion 400, and the hub portion 400. The disc-shaped second flange 200 is provided. The hub portion 400 has a bottomed cylindrical shape, and gear teeth 401 that engage with drive teeth of the drive shaft of the tape drive are formed in an annular shape on the bottom surface, and a stepped portion 402 is formed around the gear teeth 401. Is formed.

  The second flange 200 has an opening 201 through which the gear teeth 401 can be inserted in the central portion, and the second flange 200 stands around the opening 201 toward the side opposite to the first flange 300 side. An annular wall 201a is provided. As shown in FIG. 11 and FIG. 12, a plurality of welding ribs 403 and the height direction of the second flange 200 (the same direction as the height direction of the hub portion) are provided on the end surface of the annular wall 201 a on the first flange 300 side. And a plurality of pedestals 404 for determining the position of (). These are alternately arranged along the inner periphery of the second flange 200, and when the second flange 200 and the hub are welded using ultrasonic vibration, they become a flat surface, and the step 402 (see FIG. 10).

  In addition, since the second flange 200 is formed using a mold having a plurality of gates arranged at equal intervals in the circumferential direction, for example, on the inner circumferential surface of the annular wall 201a, A plurality of gate traces 405 protruding in the direction are formed (see, for example, Patent Documents 1 to 3).

By the way, at present, there is a demand for higher recording capacity of magnetic tape cartridges along with improvement in technical level. As a means for increasing the recording capacity of the magnetic tape cartridge, for example, there is a method of increasing the width of the magnetic tape. However, from the viewpoint of ensuring compatibility with the conventional recording / reproducing apparatus, the width of the magnetic tape cannot be increased without limitation. Therefore, the gap between the magnetic tape wound around the hub portion 400 and the first flange 300 or the second flange 200 is set as narrow as possible. The main surfaces of the first flange 300 and the second flange 200 facing the magnetic tape side are required to have small surface waviness (surface amplitude), that is, good flatness (see FIG. 10).
JP-A-11-66811 JP-A-11-203825 JP 11-53862 A

  However, when the second flange 200 is molded, the resin density differs between a portion relatively near the gate and a portion far from the gate. Therefore, the degree of resin shrinkage after molding also differs between a portion near the gate mark 405 and a portion far from the gate mark 405. In particular, since the resin density is high near the gate mark 405, the degree of resin shrinkage is very large. Therefore, as shown in FIG. 12, a raised portion 407 in which the resin swells is formed at a position located almost directly above the gate mark 405 in the end surface 406 of the annular wall 201a (see FIG. 12).

  When welding the second flange 200 and the hub portion 400, the welding horn 800 is pressed against the end surface 406 of the annular wall 201a. At the beginning of oscillation, the welding horn 800 is brought into contact with the raised portion 407 due to the presence of the raised portion 407. Only touch. Therefore, at the beginning of oscillation, the vibration 900 is propagated with the raised portion 407 as a starting point, so that a time difference occurs at the start of melting of each melting rib 403. Further, the difference in resin density also causes a time difference at the start of melting of each melting rib 403.

  From the above, if the pressurization and oscillation by the welding horn 800 are continued until all the welding ribs 403 are sufficiently melted, the welding ribs 403 disposed closest to the gate mark 405 are melted more than necessary. This causes a phenomenon that the height is lower than other welding ribs, so-called “sinking”. This “sinking” reduces the flatness of the surface of the second flange 200 facing the magnetic tape, and the magnetic tape is bent such that the surface contacts the edge of the magnetic tape and the edge of the magnetic tape is bent. There was a risk of bringing about.

  Therefore, the present invention provides a magnetic tape take-up reel with a flat surface of the flange facing the magnetic tape.

  The method for manufacturing a reel for winding a magnetic tape according to the present invention includes a cylindrical hub portion on which a magnetic tape can be wound on an outer periphery, a disk-like shape projecting radially from the outer periphery of the hub portion, and having an opening at a central portion. A reel for winding a magnetic tape comprising a step of welding the hub and the flange using ultrasonic vibration, the flanges alternately along the inner periphery thereof A plurality of welding ribs and a plurality of pedestals arranged, and a gate mark forming a part of an inner peripheral surface of the flange, and disposed closest to the gate mark among the plurality of welding ribs. When the welding rib is a welding rib α, the height of the pedestal A arranged on both sides of the welding rib α among the plurality of pedestals is higher than the height of the other pedestals B. And

  According to the method for manufacturing a reel for winding a magnetic tape of the present invention, the height of the pedestals arranged on both sides of the welding rib arranged closest to the gate mark is higher than the height of the other pedestals. The “sinking” of the welding rib can be suppressed. Therefore, according to the present invention, it is possible to provide a magnetic tape take-up reel with a good flatness of the surface of the flange facing the magnetic tape.

  Hereinafter, an example of the present invention will be described with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1, a magnetic tape take-up reel 1 manufactured by the manufacturing method of the present embodiment includes a hub portion 4 around which a magnetic tape can be wound and a pair of flanges 2 and 3. ing. The shape of the hub portion 4 is, for example, a bottomed cylindrical shape, and gear teeth 41 are formed in an annular shape on the bottom surface, and a stepped portion 42 is formed in an annular shape around the gear teeth 41. The gear teeth 41 engage with the drive teeth of the drive shaft of the tape drive when the tape cartridge incorporating the reel 1 is set in the tape drive.

  Each of the pair of flanges 2 and 3 protrudes radially from both longitudinal ends of the hub portion. The shapes of the flanges 2 and 3 are both disk-shaped with openings 21 and 31 at the center. The flange 3 (hereinafter also referred to as “first flange”) is integrally formed with the hub portion 4 when the hub portion 4 is formed, and the flange 2 (hereinafter also referred to as “second flange”) is formed as the hub portion 4. Separately, after being molded by an injection molding method or the like, it is welded to the stepped portion 42 of the hub portion 4 using ultrasonic vibration. The second flange 2 includes an annular wall 21 a erected around the opening 21 toward the side opposite to the first flange 3 side.

  2 is a plan view of the second flange 2 before being welded to the hub portion 4 as seen from the hub portion 4 side, and FIG. 3 is a plan view showing a part X of the inner peripheral surface of the second flange 2. It is a conceptual diagram.

  As shown in FIG. 2, on the end surface of the annular wall 21a on the first flange 3 side, a plurality of welding ribs 12 and the height direction of the second flange 2 (the thickness direction of the reel for winding the magnetic tape and the hub portion) A plurality of pedestals 15 for determining the position in the same direction as the longitudinal direction) are provided so as to project. These are alternately arranged along the inner periphery of the second flange 2. The plurality of welding ribs 12 and the plurality of pedestals 15 each have an arc shape and are arranged at substantially equal intervals.

  Although there is no restriction | limiting in particular about the shape of each welding rib 12, From a viewpoint of welding efficiency improvement, for example, the shape of a cross section (cross section seen when each welding rib 12 is cut | disconnected in the same direction as the radial direction of the 2nd flange 2). Is preferably formed to be substantially triangular. On the other hand, since the pedestal 15 has a role of determining the position of the second flange 2 in the height direction, for example, it is preferable that the pedestal 15 includes a plane parallel to the surface of the opposing hub portion.

  Since the 2nd flange 2 is shape | molded using the metal mold | die provided with the some gate arrange | positioned at equal intervals in the circumferential direction, it protruded radially inward on the internal peripheral surface of the annular wall 21a. A plurality of gate traces 5 are formed. That is, a part of the inner peripheral surface of the first flange 2 is formed after the plurality of gates.

  In the present application, among the plurality of welding ribs 12, the welding rib arranged closest to each gate mark 5 is the welding rib α12a, and the other welding ribs are the welding ribs 12b. Is a distinction for convenience of explanation, and there is no difference between the welding rib α12a and the welding rib 12b with respect to the shape or the like of the welding rib itself (see FIGS. 2 and 3).

  On the other hand, the plurality of bases 15 include two or more kinds of bases having different heights, and the height of the bases A15a arranged on both sides of each welding rib α12a is higher than the heights of the other bases B15b. It is set (see FIG. 3). In FIG. 2, a plurality of pedestals 15 are denoted by a to l. In this example, pedestals a, b, d, e, g, h, j, and k are the pedestals A, and pedestals c, f, i, and l are pedestals B.

  As shown in FIG. 3, a resin after molding is provided at a position located almost directly above each gate mark 5 on the end surface 16 on the opposite side of the end surface of the annular wall 21 a on the welding ribs 12 a and 12 b side. There is a ridge 17 caused by the contraction.

  As mentioned above, although the example of the 2nd flange 2 used for the manufacturing method of the reel for magnetic tape winding of this embodiment was demonstrated using FIG. 2 and FIG. 3, the structure of the 2nd flange 2 is not limited to this. In the example shown in FIGS. 2 and 3, the number of bases B15b arranged between a pair of gate traces 5 adjacent in the circumferential direction is one, but a plurality of bases B15b may be provided. In this case, it is preferable that the heights of the plurality of bases B become lower as the distance from the gate mark 5 in the circumferential direction decreases. This is because in the magnetic tape take-up reel manufactured using the second flange, the planarity of the main surface of the second flange 2 facing the magnetic tape becomes better.

  As for the number of gate marks 5, as long as the condition that “the height of the pedestal A arranged on both sides of the welding rib α is higher than the height of the other pedestal B” is satisfied for each gate mark 5. There is no restriction | limiting in particular and 1 or more may be sufficient. Also in this case, it is preferable that the height of the pedestal B15b is lower as it is farther from the gate mark 5 along the circumferential direction. This is because in the magnetic tape take-up reel manufactured using the second flange, the planarity of the main surface of the second flange 2 facing the magnetic tape becomes better.

  As for the position of the gate trace 5, the gate trace 5 forms a part of the inner peripheral surface of the second flange, and “the height of the pedestal A arranged on both sides of the welding rib α is equal to that of the other pedestal B. As long as the condition “higher than the height” is satisfied, there is no particular limitation. However, as in the example shown in FIGS. 2 and 3, the center of the circumferential length of the welding rib and the center of the gate trace 5 Are preferably arranged so as to substantially correspond to each other. Since the top of the raised portion 17 is located almost directly above the center of the gate mark 5, when the second flange 2 and the hub portion 4 are welded, ultrasonic vibration energy is applied to the entire welding rib α with good uniformity. This is because the second flange 2 and the hub portion 4 can be favorably welded.

  In the example shown in FIGS. 2 and 3, each gate mark 5 forms a portion corresponding to a predetermined welding rib 12 (welding rib α12a) in the inner peripheral surface 21b of the second flange 2. Therefore, the second flange has a structure in which two welding ribs 12b are arranged between the gate traces 5 adjacent in the circumferential direction. However, the number of the welding ribs 12b arranged between the gate traces 5 adjacent to each other in the circumferential direction is not particularly limited, and “the height of the pedestal A arranged on both sides of the welding rib α is the other pedestal B. As long as the condition “higher than the height of” is satisfied, two or more may be used.

  In the example described with reference to FIGS. 1 to 3, the first flange 3 is integrally formed with the hub portion 4 when the hub portion 4 is formed. After being molded separately, it may be welded to the hub portion 4 using ultrasonic vibration and integrated with the hub portion 4. In this case, if the structure of the first flange 3 is the same as that of the second flange 2, the flatness of the main surface of the first flange 3 facing the magnetic tape will be good.

  Further, the magnetic tape take-up reel of this embodiment does not necessarily have to include both the second flange 2 and the first flange 3, and either one of the flanges is used as a hub portion by using ultrasonic vibration. If it is welded, the other flange may be omitted.

  Next, an example of a method for manufacturing the magnetic tape take-up reel of this embodiment will be described with reference to FIG. The manufacturing method of the magnetic tape take-up reel of this embodiment includes a step of welding the hub portion and the second flange using ultrasonic vibration. This step is performed as follows, for example.

  First, as shown in FIG. 4A, the second flange 2 and the hub portion 4 are overlapped so that the welding ribs 12 a and 12 b are in contact with the stepped portion of the hub portion 4. The welding horn 8 is brought into contact with the side opposite to the 4 side. At this time, since the welding horn 8 is in contact with only the raised portion 17 disposed immediately above the gate mark 5, there is a gap between a part of the end surface 16 of the annular wall including the raised portion 17 and the welded horn 8. Arise.

  As shown in FIG. 4B, when ultrasonic waves are oscillated from the welding horn 8, vibration is propagated to the second flange 2 starting from the raised portion 17. At the start of oscillation, the welding horn 8 is in contact with only the raised portion 17 and the resin density of the relatively close portion of the gate mark 5 in the second flange 2 is higher than that of the distant portion, so that the gate portion 5 is relatively. There is a time difference that cannot be ignored at the start of melting between the welding ribs 12a disposed near the other and other welding ribs 12b disposed far away.

  Therefore, when the conventional second flange having the same height of the plurality of pedestals is used, if pressurization and oscillation by the welding horn 8 are continued until all the welding ribs are sufficiently melted, they are arranged near the gate trace 5. As for the welding ribs, a phenomenon of melting more than necessary and lowering the height of the other parts, that is, so-called “sinking” occurs. As a result, the flatness of the surface of the second flange 2 facing the magnetic tape is impaired.

  However, in the manufacturing method of the present embodiment, the second flange 2 includes the pedestal 15a and the pedestal 15b having different heights. Therefore, when the melting of the melting rib 12a proceeds, among the pedestals, the pedestal 15b Only the pedestal 15 a having a high height contacts the hub portion 4. The pedestal 15a in contact with the hub portion 4 functions as a resistance against a load by the welding horn 8, and suppresses “sinking” of the welding rib 12a on both sides of the welding rib 12a (welding rib α).

  Thus, while the position of the second flange in the height direction is held by the pedestal 15a, melting of the welding rib 12b that is slower than the welding rib 12a at the start of melting proceeds. Then, as shown in FIG. 5A, the end face 16 of the annular wall 21a facing the welding horn 8 is also flattened. Finally, as shown in FIG. 5B, the plurality of welding ribs 12a and 12b and the plurality of bases 15a and 15b (see FIG. 4A) become flat surfaces, and the plurality of welding ribs 12a and 12b are formed. The hub portion 4 is welded to the step portion 42.

  As described above, according to the manufacturing method of the present embodiment, “sinking” of the welding rib disposed near the gate trace 5 can be suppressed. Therefore, the flatness of the surface of the second flange 2 facing the magnetic tape is good.

  Next, the planarity of the second flange of the obtained magnetic tape take-up reel was evaluated as follows.

  FIG. 6 is a diagram schematically showing a cross section of the magnetic tape take-up reel of the present embodiment. The tip of the probe (probe) of the measuring device (Mitutoyo Co., Ltd., 519-322) is located at a location C where the main surface 2a of the second flange 2 on the hub portion 4 side and the outer peripheral surface 4a of the hub portion 4 communicate with each other. As described above, the tip of the probe was applied to the main surface 2a of the second flange 2 on the hub portion side. In this state, the deflection width of the probe was measured while rotating the magnetic tape take-up reel 1. The measurement was performed at intervals of 8 degrees, and 45 positions were measured so as not to overlap each other. The measurement was performed in a state where the gear teeth of the magnetic tape take-up reel were engaged with a metal reference gear that can be engaged with the gear teeth. The reference gear or the drawing thereof is provided by the corresponding recording / reproducing apparatus manufacturer for standardization, and is made with high accuracy. Therefore, when the above measurement is performed in a state where the magnetic tape take-up reel of this embodiment is engaged with this, surface waviness can be accurately measured.

  It should be noted that the smaller the difference between the maximum value and the minimum value of the measured value, that is, the smaller the amplitude of the probe, the smaller the degree of surface undulation (surface amplitude), and the better the flatness.

  FIG. 7 shows the measurement results (circles) of the magnetic tape take-up reel manufactured by the manufacturing method of the present embodiment, and FIG. 8 uses the second flange in which the heights of the plurality of bases are all equal. The measurement result (circle) about the conventional reel for magnetic tape winding produced by FIG.

  As shown in FIGS. 7 and 8, the surface waviness is 0.06 mm or less in the conventional magnetic tape take-up reel, whereas the magnetic tape take-up reel manufactured by the manufacturing method of the present embodiment. Then, it was 0.03 mm or less.

  Further, the probe tip is similarly applied to the main surface 2a of the second flange 2 on the hub portion 4 side so that the tip of the probe is along the outer periphery of the second flange 2. The width was measured. The measurement results (square marks) are also shown in FIGS. In this case, the surface waviness is 0.10 mm or less in the conventional magnetic tape take-up reel, whereas it is 0.06 mm or less in the magnetic tape take-up reel manufactured by the manufacturing method of this embodiment. It was.

  From the above results, according to the manufacturing method of the present embodiment, a magnetic tape take-up reel is provided in which the flatness of the surface of the second flange facing the magnetic tape is better than that of the conventional magnetic tape take-up reel. I was able to confirm that In addition, since the degree of surface undulation tends to increase toward the outer periphery of the second flange, according to the manufacturing method of the present embodiment, the undulation of the main surface on the hub portion side of the second flange is 0.06 mm. It was confirmed that the following reels for winding a magnetic tape could be provided.

(Embodiment 2)
In the second embodiment, a tape cartridge using the magnetic tape take-up reel described in the first embodiment will be described. In the tape cartridge of the present embodiment, the constituent members other than the magnetic tape take-up reel may be the same as the conventional one, and are not limited to the following.

  As shown in FIG. 9, the tape cartridge 20 of this embodiment includes the above-described magnetic tape take-up reel 1, a magnetic tape 25 wound around the magnetic tape take-up reel, and a case 24 containing these. Contains. The case 24 is formed, for example, by fastening an upper lid 24a and a lower lid 24b with screws or the like. The magnetic tape take-up reel 1 is rotatably accommodated in the case 24 and is pressed and urged downward in this figure by a compression coil spring 28 acting via a component 27. This prevents the magnetic tape take-up reel 1 from spinning when not in use.

  An opening 29 is formed at the center of the lower lid 24b. When the tape cartridge 20 of the present embodiment is set in a corresponding recording / reproducing apparatus (drive), the gear teeth 41 exposed from the opening 29 are The drive teeth of the drive shaft of the drive are engaged, and the magnetic tape 25 is pulled out of the case by the tape pull-out mechanism of the drive, and data recording / reproduction is performed.

  The tape cartridge 1 shown in FIG. 9 is a single reel type that houses one reel. However, the tape cartridge 1 of this embodiment is not limited to this, and is a double reel type that contains two reels. May be.

  In addition, the magnetic tape take-up reel of the present embodiment is not limited to one used by being housed in a tape cartridge case. For example, the magnetic tape take-up reel is preliminarily built in a recording / reproducing apparatus (drive) and is It may be a magnetic tape take-up reel for temporarily taking up the magnetic tape fed in.

  According to the method for manufacturing a magnetic tape take-up reel of the present invention, a magnetic tape take-up reel having a good flatness on the surface of the flange facing the magnetic tape can be provided. Useful as.

1 is an exploded perspective view showing an example of a magnetic tape take-up reel of the present invention. The top view of the 2nd flange used for an example of the manufacturing method of the reel for magnetic tape windings of this invention Schematic diagram representing the portion X of the second flange shown in FIG. (A) And (B) is process drawing explaining an example of the manufacturing method of the reel for magnetic tape windings of this invention. (A) And (B) is process drawing explaining an example of the manufacturing method of the reel for magnetic tape windings of this invention. Schematic cross-sectional view showing an example of a magnetic tape take-up reel of the present invention The graph which showed the measurement result of the surface waviness about an example of the reel for magnetic tape winding of this invention The graph which showed the measurement result of the surface waviness about an example of the reel for magnetic tape winding of this invention Schematic sectional view showing an example of the tape cartridge of the present invention An exploded perspective view showing an example of a conventional reel for winding a magnetic tape The top view of the 2nd flange used for an example of the manufacturing method of the conventional reel for magnetic tape winding Schematic diagram representing the portion Y of the second flange shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reel for magnetic tape winding 2 2nd flange 3 1st flange 4 Hub part 5 Gate trace 8 Welding horn 12,12a, 12b Welding rib 15,15a, 15b Base 17 Raised part 20 Tape cartridge 24 Case 25 Magnetic tape

Claims (5)

Manufacturing method of magnetic tape take-up reel having cylindrical hub portion on which magnetic tape can be wound on outer periphery, and disk-shaped flange projecting radially from the outer periphery of hub portion and having an opening in the central portion Because
Including welding the hub portion and the flange using ultrasonic vibration,
It said flange has a gate mark forming part of the inner peripheral surface of the flange, the step wherein the hub portion and facing said flange surface inner periphery a plurality of bonding ribs and a plurality of which are arranged alternately along the in With a pedestal ,
In the step, the welding rib and the hub are welded,
When the welding rib arranged closest to the gate mark among the plurality of welding ribs is the welding rib α,
Among the plurality of pedestals, the height of the pedestal A arranged on both sides of the welding rib α is the same as the height of the welding rib α welded to the hub portion in the above step. A method of manufacturing a reel for winding a magnetic tape, characterized in that it is set higher than the height of another pedestal B so as to prevent the height of the magnetic tape from being lowered . The flange includes a plurality of the gate marks,
The magnetic tape winding according to claim 1, wherein a condition that the height of the pedestal A arranged on both sides of the welding rib α is higher than the height of the pedestal B is satisfied for each gate mark. Manufacturing method for reels. A plurality of the pedestals B are arranged between a pair of adjacent gate traces,
3. The method of manufacturing a magnetic tape take-up reel according to claim 2, wherein the height of the plurality of bases B is lower as the distance from the gate mark along the circumferential direction is lower.   The magnetic tape take-up reel manufacturing method according to claim 1, wherein the gate mark is disposed at a position corresponding to the welding rib α. The hub portion has a bottomed cylindrical shape, and gear teeth are formed on the bottom surface thereof.
The flange includes an annular wall formed around the opening;
The plurality of welding ribs and the plurality of pedestals are formed on one end face of the annular wall and facing the hub portion in the step ,
The hub portion is formed in an annular shape around the gear teeth because the outer diameter of the portion close to the bottom surface is smaller than the other portion, and faces the welding rib and the plurality of bases in the step. Including steps,
The manufacturing method of the reel for magnetic tape winding of Claim 1 in which the said welding rib and the said level | step-difference part of the said hub part are welded in the said process.

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