JPH0725908Y2 - Rotating roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a plastic rotating roller rotatably supported by a shaft.

[Outline of the Invention] In the present invention, an inner cylinder portion, an outer cylinder portion, and a connecting portion for connecting them are integrally formed by injection molding, and are rotatably supported by a shaft inserted in a shaft insertion hole of the inner cylinder portion. In the rotating roller, the diameter of the shaft insertion hole corresponding to the inner side of the connecting portion is formed to be larger than that of the other portion, which is caused by a weld line or the like generated on the surface of the shaft insertion hole by injection molding. Rotation noise can be prevented.

[Prior Art] A high-track-density tape cassette has been proposed as an external recording medium for a computer (US Pat. No. 4,198,013).
See the specification). In this tape cassette, a tape running path is formed between a pair of reels, and a tape running on the tape running path is wound around each of the pair of reels.
An endless drive belt is pressed against the outermost circumference of the tape wound around a pair of reels, and this drive belt is hung on one drive roller and two driven rollers for a total of three rotating rollers. There is. When the drive belt travels due to the rotation of the drive roller, the tape receives a frictional force at a position where it is pressed against the drive belt, and the frictional force causes the tape to travel. A conventional example of a driven roller which is a rotating roller is shown in FIG.

In FIG. 5, the driven roller 16 is integrally formed by injection molding, and the inner cylindrical portion 30 and the outer cylindrical portion 31 are connected to each other.
It consists of 32 and. The drive belt 25 is hung on the outer contact surface 31a of the outer cylinder portion 31. A straight shaft insertion hole 34 is formed in the inner cylinder portion 30, and the shaft 18 is inserted into the shaft insertion hole 34. Grease 24 is provided between the shaft insertion hole 34 and the shaft 18.
Are intervened to prevent wear of the both and to give a constant tension to the drive belt 25 by viscous resistance of the grease 24.

[Problems to be Solved by the Invention] Here, the driven roller 16 has the inner tubular portion 30 and the outer tubular portion 31 as described above.
And the connecting portion 32, and the thinning grooves 33 are formed on the upper and lower sides of the connecting portion 32 to prevent deformation due to thermal contraction after injection of swelling oil. However, since the thickness of the connecting portion 32 is still thick in the width direction, the shaft insertion hole that contacts the inside of the connecting portion 32.
There was a high possibility that weld lines and the like would be formed on the surface of 34 due to thermal contraction after the injection of swelling oil. When the weld line is formed, the weld line comes into contact with the shaft 18 to cause problems such as rotation noise and unstable tension of the drive belt 25.

Therefore, an object of the present invention is to provide a rotary roller that prevents rotation noise and the like due to weld lines and the like generated on the surface of the shaft insertion hole by injection molding.

[Means for Solving the Problems] In the rotating roller of the present invention for achieving the above object, the inner cylindrical portion, the outer cylindrical portion, and the axially central portions of the inner cylindrical portion and the outer cylindrical portion are connected to each other. The connecting portion is integrally formed by injection molding, is rotatably supported by the shaft inserted into the shaft insertion hole of the inner tubular portion, and is rotated by an external force from another member that comes into contact with the external contact surface of the outer tubular portion. In the rotating roller, a region of at least the width of the connecting portion of the shaft insertion hole is formed in a large diameter portion having a larger radial dimension than both ends of the shaft insertion hole.

[Operation] In the rotary roller, both ends of the shaft insertion hole are held with a constant space dimension with respect to the shaft, and even if there is a weld line on the surface of the shaft insertion hole which is the inner part of the connecting portion, this weld line Does not touch the shaft.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment in which the present invention is applied to a driven roller of a tape cassette.

In FIGS. 1 and 2, a case 1 is composed of an upper case part 2 made of plastic and a lower case part 3 made of metal, and a lower surface of a side wall part 4 provided at a peripheral edge of the upper case part 2 is a case part. It is attached to the periphery of 3. A supply reel 5 and a take-up reel 6 are rotatably provided in the case 1. A tape running path 8 for running the tape 7 is formed between the supply reel 5 and the take-up reel 6.
The tape running path 8 has two guide pins 9 and 10 near the front surface of the case 1, between the supply reel 5 and the guide pin 9, between the guide pin 9 and the guide pin 10, and between the guide pin 10 and the winding. Pins 11, 12, and 13 are respectively provided upright on the lower case portion 2 between the reel 6 and the reel 6. The tape 7 is wound around the supply reel 5 at one end and the tape running path 8 at the other end.
Is wound around the take-up reel 6 after traveling.
That is, the tape 7 guided from the supply reel 5 is wound around the guide pin 9 at a predetermined angle, the direction of the tape 7 is changed, and the tape 7 is run near the front surface of the case 1 in parallel with the front surface. And the guide pin
It is wound around a predetermined angle 10 and is redirected again to be guided to the take-up reel 6.

The tape running path 8 is provided with a tape exposing portion 20 for exposing a part of the running tape 7 to the outside of the case 1.
The exposed tape portion 20 is used for the tape 7 when the drive device is mounted.
The tape exposing portion 20 is opened and closed by a cover 23 at a position where the tape is pressed against the head. The cover 23 has a shape covering the space formed by the cutout portion 21, is rotatably supported by the shaft 26 of the lower case portion 3, and is biased to the closed position by the spring force of the coil spring 29. There is.

The tape running drive mechanism 14 includes a drive roller 15 at the center of the front of the case 1 and a pair of driven rollers 1 at the rear left and right corners.
It has 6 and 17 respectively. The drive roller 15 is rotatably supported by a shaft 18 provided upright on the lower case portion 3,
Grease for preventing wear is interposed between the shaft 15 and the shaft 18. An upper portion of the drive roller 15 is formed in a large diameter portion 15a, and a part of the large diameter portion 15a is exposed to the outside of the case 1 through the hole 28 of the upper case portion 2. Further, the pair of driven rollers 16 and 17 are provided on the lower case portion 3 as shown in FIG. 3 (only the sectional view of one driven roller 16 is shown in FIG. 3). The shafts 18 and 18 are rotatably supported by the shafts 18 and 18, and the stoppers 19 and 19 are fixed to the upper ends of the shafts 18 and 18 to prevent the movement in the thrust direction. Grease 24 is interposed between each driven roller 16 and 17 and the outer surface of each shaft 18 and 18. This grease has a temperature between -10 ° C and 60 ° C and a viscosity coefficient of 50 poise to 500 poise.

An endless drive belt 25 is wound around the drive roller 15 and the pair of driven rollers 16 and 17. The drive belt 25 is flexible and includes the drive roller 15 and each driven roller.
Supply reel 4 and take-up reel 6 are located between 16 and 17.
It is pressed against the outermost circumference of the tape 7 wound around.

Reference numeral 27 in the figure is a mirror body for detecting the tape end.

FIG. 3 shows a sectional view of one driven roller 16. In FIG. 3, the driven roller 16 is integrally formed by injection molding, and includes an inner tubular portion 30, an outer tubular portion 31 coaxial with the inner tubular portion 30, and a connecting portion 32 for connecting them at a central portion in the axial direction thereof. The thinned groove 33 is formed above and below the connecting portion 32. A gentle mountain-shaped convex portion is formed at the center of the outer peripheral surface of the outer cylindrical portion 31, and the outer peripheral surface of the outer cylindrical portion 31 is configured as an external contact surface 31a on which the drive belt 25 is hung. A shaft insertion hole 34 is formed in the center of the inner tubular portion 30,
The shaft 18 is inserted into the shaft insertion hole 34. Connecting part 33
Inside of the connecting portion 33, the location of the shaft insertion hole 34, which is at least the region (L) of the width (d) or more, is larger than the radius (r ₀ ) of both ends of the shaft insertion hole 34 (r). Is formed in the large diameter portion 34a. In this embodiment, the large-diameter portion 34a is formed so that the radius gradually decreases from the center toward the upper and lower ends, but the radius between the large-diameter portion 34a and the other portions suddenly changes in radius dimension. You may form in step shape. However, if it is formed as in this embodiment, there is an advantage that die cutting becomes easy.

The large diameter portion 34a can be easily formed in the shaft insertion hole 34 by forming the large diameter portion 34a of the mold into a gentle convex shape. Alternatively, it may be formed by utilizing heat shrinkage (so-called sink mark) after the injection of the swelling oil.

The other driven rollers 17 have the same structure, and the drive roller 15 has substantially the same shaft insertion hole.

FIG. 4 shows another embodiment of the driven roller 16, which differs from the above embodiment in that a spiral groove 35 is formed on the surface of the shaft insertion hole 34. Since the configuration is the same as that of the above-mentioned embodiment, the same reference numerals are given and the description thereof is omitted. The driven roller 16 of this embodiment is used when it is configured as a driven roller having a smaller size than that described above, and since the grease is retained in the spiral groove 35, the absolute amount of grease between the shaft and the shaft insertion hole 34 is reduced. Since the amount is a predetermined amount or more, it is possible to provide a small driven roller with excellent durability.

The operation of the tape cassette will be described below.

When the tape cassette is attached to the drive device, the cover 23 rotates against the spring force of the coil spring 29 during this loading process. When the cover 23 is rotated to the open position, the head of the drive device is brought into pressure contact with the tape 7 located in the tape exposed portion 20 and the drive roller 15 is attached to the roller of the drive device.
Is pressed. When the drive roller 15 rotates due to the rotation of the roller of the drive device, the driven rollers 16 and 17 also rotate and the drive belt 25 travels in the direction of the arrow in FIG. When this drive belt 25 runs, the tape 7 will be the drive belt 25.
A frictional force is received at a pressure contact point with and the vehicle travels in the direction of the arrow in FIG. 2 by this frictional force.

When the drive belt 25 runs, the drive roller 15 and the two driven rollers 16 and 17 rotate together. Further, these rotary rollers are held at both end portions (positions where the radial dimension is small) of the shaft insertion hole 34 with a constant space dimension with respect to the shaft 18, and the large diameter portion 34a of the shaft insertion hole 34 is Even if there is a weld line, etc., it does not come into contact with the shaft 18, so rotation noise due to the weld line, etc. does not occur, and the driven rollers 16, 17
The running resistance exerted on the drive belt 25 does not become unstable.

When the drive belt 25 travels, each driven roller 1
Since 6 and 17 rotate against the viscous resistance of the grease 24, the drive belt 25 has a small tension (a small extension amount) at a portion between the drive roller 15 and one driven roller 16, and the drive belt 25 and the other driven roller 16 have a small tension. The tension between the driven rollers 17 is large (the amount of expansion is large), and a belt tension difference occurs. When traveling in the opposite direction, the magnitude of tension is reversed. Since the tape 7 travels while the tension proportional to the belt tension difference acts on the tape 7, the tape tension proportional to the belt tension difference acts on the tape 7.

Therefore, this tape tension is obtained by the running resistance of the driven rollers 16 and 17 to the drive belt 25. Here, if the gap dimension between the shaft 18 and the shaft insertion hole 34 is too large, the running resistance becomes unstable (fluctuating) due to rattling or the like, and the gap dimension is too small (compared to the conventional one). As described above, when the weld line protrudes from the other surface) and the running resistance corresponding to the viscous resistance of the grease 24 cannot be obtained, it is necessary to set the above gap size within a predetermined range.
In this embodiment, since the driven rollers 16 and 17 are held at both end portions of the shaft insertion hole 34 with a constant gap size with respect to the shaft 18, the running resistance is stabilized, and there is a weld line. However, since it is a portion where the gap size is wide, a running resistance corresponding to the viscous resistance of the grease 24 can be sufficiently obtained, and from the above, a stable tape tension with a predetermined value can be obtained.

[Advantages of the Invention] As described above, according to the present invention, the inner tubular portion, the outer tubular portion, and the connecting portion that connects them are integrally formed by injection molding and inserted into the shaft insertion hole of the inner tubular portion. In the rotary roller rotatably supported by the shaft, the diameter of the shaft insertion hole, which corresponds to the inner side of the connecting portion, is larger than that of the other parts, so that it is generated on the surface of the shaft insertion hole by injection molding. This has the effect of preventing rotation noise and the like due to weld lines and the like.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention, FIG. 1 is an exploded perspective view of a tape cassette, FIG. 2 is a plan view of the tape cassette excluding an upper case portion, and FIG. 3 is a driven roller. A sectional view and FIG. 4 are partial sectional views of a driven roller of another embodiment, and FIG. 5 is a sectional view of a conventional driven roller. 15 ... Drive roller (rotating roller), 16, 17 ... Followed roller (rotating roller), 30 ... Inner cylinder part, 31 ... Outer cylinder part, 31a ... External contact surface, 32 ... Connection part, 34 ... Shaft insertion hole, 34a … Large diameter part.

Claims (1)

[Scope of utility model registration request] 1. An inner tubular portion, an outer tubular portion, and a connecting portion that connects the inner tubular portion and the outer tubular portion at axially central portions thereof are integrally formed by injection molding, and the inner tubular portion is axially inserted. A rotating roller that is rotatably supported by a shaft inserted in a hole and that is rotated by an external force from another member that comes into contact with the external contact surface of the outer cylinder part, wherein the region is at least the width of the connecting part of the shaft inserting hole. Is formed in a large diameter portion having a larger radial dimension than both ends of the shaft insertion hole.