JPH09242752A - Capstan bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capstan bearing by which reduction in the part number and facilitation of assembling can be promoted further. SOLUTION: An area having a length not more than almost half of the circumferential direction in the circumferential direction of a circumferential surface of a capstan, is rotatably supported by one first capstan bearing surface area 10c of mutually different two positions running in the lengthwise direction of the capstan 14, and an area having a length not more than almost half of the circumferential direction positioned on the almost exact opposite side of the one first capstan bearing surface area 10c in the circumferential direction of the circumferential surface, is rotatably supported by the other second capstan bearing surface area 10d of the two positions, and the rotational center line 14a of the capstan is regulated in parallel to the rotational center line 16a of a pinch roller 16 to be contacted with and separated from the capstan.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capstan bearing that rotatably supports a capstan.

[0002]

2. Description of the Related Art In recent years, capstan bearings have been formed integrally with a chassis in order to reduce the number of parts and facilitate assembly, and synthetic resin is used as the material. There is. In this case, since the synthetic resin has lower rigidity than metal, in order to rotate the capstan with desired eccentricity, the capstan's peripheral surface can be rotated within a relatively long range along the longitudinal direction of the capstan. Must support. However, when the capstan bearing is made of synthetic resin, the draft angle of the injection molding type is necessary, so the bearing hole of the capstan bearing is made into a truncated truncated cone shape, and the capstan bearing is formed deep in the bearing hole with a small diameter. A bearing that rotatably supports a part of the circumferential surface along the longitudinal direction of the capstan, and the capstan is inserted near the entrance of the bearing hole having a large diameter to rotatably support the capstan. An annular fitting member having a hole is fitted therein.

[0003]

Since the injection molding die has a draft angle, it is unavoidable to adopt a truncated truncated cone bearing hole.
As a result, in the conventional capstan bearing as described above, which uses the annular fitting member to rotate the capstan with a desired eccentricity accuracy, the annular fitting member is different from the capstan bearing and the chassis. The work of independently forming the body and incorporating it into the truncated truncated cone-shaped bearing hole is an obstacle to the reduction of the manufacturing cost and the assembly cost of the capstan bearing.

The present invention has been made under the above circumstances, and an object of the present invention is to provide a capstan bearing which can further reduce the number of parts and facilitate assembly.

[0005]

In order to achieve the objects of the invention as described above, a first capstan bearing according to the invention comprises: two different positions along the length of the capstan. On the other hand, a predetermined region in the circumferential direction in the circumferential direction of the capstan is rotatably supported, and at the other of the two positions, the one predetermined region in the circumferential direction of the circumferential surface is substantially the same. A predetermined region in the circumferential direction located on the diametrically opposite side is rotatably supported, and the rotation center line of the capstan is regulated to be parallel to the rotation center line of the pinch roller that is brought into contact with and separated from the capstan, It is characterized by that.

In the second capstan bearing according to the present invention, the first capstan bearing having the above-mentioned structure is integrated with the chassis provided with the first capstan bearing by a synthetic resin. Form.

According to the third capstan bearing according to the present invention, in the first or second capstan bearing characterized by being configured as described above, two different capstan bearings along the longitudinal direction of the capstan are provided. One of the positions is located on the side receiving the pressure of the pinch roller in the circumferential direction of the capstan, and the other is located on the side opposite to the side receiving the pressure of the pinch roller, and the contact area of the one is larger than the contact area of the one on the capstan. Increase the contact area on the other side.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the capstan bearing of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1A is a schematic vertical cross-sectional view showing a state in which a pinch roller is pressed against a capstan while one embodiment of the capstan bearing of the present invention rotatably supports the capstan. FIG. 1B is a schematic plan view showing one embodiment of FIG. 1A with the capstan removed; FIG. 2A is a drawing. 1 (A) is a schematic vertical sectional view showing a state of splitting of a split mold for injection molding of one embodiment of FIG. 1 (A); and FIG. 2 (B) is of FIG. 1 (A). It is a schematic plan view which shows the modification of one Embodiment in the state which removed the capstan.

As shown in FIGS. 1A and 1B, a capstan bearing 10 according to one embodiment of the present invention.
Is integrally molded with a chassis 12 of a tape recorder using a capstan bearing 10 and a synthetic resin. The capstan bearing 10 has a cylindrical outer cylindrical portion 10b protruding downward from the lower surface of the chassis 12 around an insertion hole 10a through which the capstan 14 is inserted. The outer peripheral surface of the outer cylindrical portion 10b is provided with a draft having a diameter that decreases as the distance from the lower surface of the chassis 12 increases.

The pinch roller 16 is selectively contacted with the upper end of the capstan 14 which is inserted through the insertion hole 10a and protrudes upward from the capstan bearing 10, and the lower end of the capstan 14 which protrudes downward from the capstan bearing 10 is contacted. A flywheel 18 is concentrically fixed to the portion, and a rotational force transmission belt 20 for transmitting rotational force from a motor (not shown) is wound around the flywheel 18.

The upper end of the inner peripheral surface of the outer tubular portion 10b is in contact with the capstan 14 on the peripheral surface of the capstan 14 on the side opposite to the side receiving the pressure of the pinch roller 16. The bearing surface region 10c is formed, and the first capstan bearing surface region 10c has a length that is substantially half or less in the circumferential direction of the capstan 14.

At the lower end, which is a position different from the first capstan bearing surface region 10c along the longitudinal direction of the capstan 14 on the inner peripheral surface of the outer tubular portion 10b, the capstan 14 is provided with respect to the capstan 14. A second capstan bearing surface region 10d is formed on the peripheral surface, which is in contact with the side on which the pinch roller 16 is pressed. The second capstan bearing surface region 10d has a length that is substantially half or less in the circumferential direction of the capstan 14. And the pinch roller 1
6 is closer to the second capstan bearing surface area 10d than the second capstan bearing surface area 10d.
Larger than the contact area of the capstan.

An area 10e on the inner peripheral surface of the outer cylindrical portion 10b, which is located below the first capstan bearing surface area 10c and is approximately half the length of the capstan 14 in the circumferential direction, on the side opposite to the pinch roller pressing portion 10e is the first area. There is a draft having a diameter that increases as it moves downward from the capstan bearing surface region 10c.

The pinch roller pressing side region 10f which is located above the second capstan bearing surface region 10d on the inner peripheral surface of the outer cylindrical portion 10b and which is half the length of the capstan 14 in the circumferential direction has a second capping region. There is a draft having a diameter that increases with increasing distance from the stun bearing surface region 10d.

1 having the above-mentioned structure
In the capstan bearing 10 according to one embodiment, the first and second capstan bearing surface regions 10c at two different positions along the longitudinal direction of the capstan 14 are provided.
10d rotatably supports the capstan 14.
Then, as shown in FIG. 1A, when the pinch roller 16 comes into contact with the upper end of the capstan 14 and presses the capstan 14 in the direction indicated by the arrow I, this pressing force is applied to the capstan 14 by the first capping. A moment is generated with the stun bearing surface region 10c as the center of rotation, and the capstan 14
Presses the first capstan bearing surface region 10c in the direction indicated by the arrow I and presses the second capstan bearing surface region 10d in the direction opposite to the direction indicated by the arrow I.

Therefore, the pressing force is stably supported by the first and second capstan bearing surface regions 10c and 10d, and the pressing force is leveraged by the capstan 14 to cause the second capstan bearing surface region 10d. The capstan contact area of the first capstan bearing surface area 10c that is loaded more than the second capstan bearing surface area 10d
Is larger than the contact area of the capstan of the first and second capstan bearing surface regions 10c, 1
0d has a greater rigidity with respect to the pressing force and can support the capstan 14 more stably, that is, with a smaller eccentricity, so as to be freely rotatable.

As described above, the first and second capstan bearing surface regions 10c and 10d of the capstan bearing 10 of the above-described one embodiment are aligned with the rotation center line 16a of the pinch roller 16 which is brought into contact with and separated from the capstan 14. On the other hand, the rotation center line 14a of the capstan 14 is regulated in parallel.

In FIG. 2A, the capstan bearing 10 of one embodiment having the above-mentioned structure is used together with the chassis 12 when injection molding is performed with synthetic resin. Two split molds 22a, 22b are 2
The two split dies 22a, 22
b is vertically divided from each other.

As shown in FIG. 2A, the first capstan bearing surface region 10c located at the upper end of the inner peripheral surface of the outer cylindrical portion 10b and the lower end portion of the inner peripheral surface of the outer cylindrical portion 10b. The pinch roller pressing side region 10f, which is located above the second capstan bearing surface region 10d and whose diameter increases as it goes upward, is formed by the upper split mold 22a. The second capstan bearing surface region 10 located at the lower end of the inner peripheral surface of the outer tubular portion 10b.
d and a pinch roller pressing which is located below the first capstan bearing surface region 10c at the upper end portion on the inner peripheral surface of the outer cylindrical portion 10b and has a downward slope that increases in diameter downwardly. The opposite side region 10e is formed by the lower split mold 22b.

In the above-described one embodiment, the first and second capstan bearing surface regions 10c and 10d of the capstan bearing 10 have a substantially semicircular concentrically arranged plane shape. If the capstan 14 can be stably and rotatably supported with an eccentricity of not more than a predetermined value, it may have a substantially triangular shape as shown in FIG.
It can be a polygonal shape having more corners. Then, in FIG. 2B, components equivalent to the various components in the one embodiment shown in FIGS. 1A and 1B are the same as those in FIGS. 1A and 1B. The reference numerals used are 10, 10b, 10c, 10d, 10e,
Each of the 10f is indicated by a reference numeral with a dash "'".

Further, although the capstan bearing 10 of the above-described embodiment projects downward from the surface of the chassis 12 along the longitudinal direction of the capstan 14,
On the contrary, the capstan 14 may be projected upward and along the longitudinal direction of the capstan 14. In this case, the outer cylindrical portion 10b is projected upward from the surface of the chassis 12, and the draft of the outer peripheral surface of the outer cylindrical portion 10b is opposite to the surface of the chassis 12 contrary to the case of the one embodiment described above. The diameter is reduced so that it goes upward.

[0022]

According to the capstan bearing of the invention described in claim 1, it is possible to obtain a shape suitable for integral molding. According to the invention described in claim 2, in addition to the effect of the capstan bearing of claim 1, the manufacturing cost of the capstan bearing can be further reduced, and the assembling can be facilitated.

According to the third aspect of the present invention, the first aspect is provided.
Alternatively, in addition to the effect of the capstan bearing of claim 2, the parallelism between the rotation center line of the pinch roller and the rotation center line of the capstan can be further improved.

[Brief description of drawings]

FIG. 1A is a schematic view showing a state in which a pinch roller is pressed against a capstan while an embodiment of the capstan bearing of the present invention rotatably supports the capstan. FIG. 3B is a vertical cross-sectional view; FIG. 3B is a schematic plan view showing one embodiment of FIG. 3A with the capstan removed.

2 (A) is a schematic vertical cross-sectional view showing a state of splitting of a split mold for injection molding of one embodiment of FIG. 1 (A); FIG. It is a schematic plan view which shows the modification of one Embodiment of (A) in the state which removed the capstan.

[Explanation of symbols]

10 ... Capstan bearing, 10a ... Insertion hole, 10b ... Outer cylinder part, 10c ... 1st capstan bearing surface area, 10d
... second capstan bearing surface region, 10e ... region opposite to pinch roller pressing side, 10f ... pinch roller pressing side region,
12 ... Chassis, 14 ... Capstan, 14a ... Rotation center line, 16 ... Pinch roller, 16a ... Rotation center line, 18
... flywheel, 20 ... rotational force transmission belt, 22a,
22b ... Split type.

Claims (3)

[Claims] 1. A capstan bearing for rotatably supporting a capstan: at two different positions along the longitudinal direction of the capstan, at one of the two positions that are different from each other in the circumferential direction of the circumferential surface of the capstan. Is rotatably supported, and at the other of the two positions, the predetermined region in the circumferential direction located on the side substantially opposite to the predetermined region on the one side in the circumferential direction of the circumferential surface is freely rotatable. The capstan bearing is characterized in that the center of rotation of the capstan is supported so as to be parallel to the center of rotation of the pinch roller that is brought into contact with and separated from the capstan. 2. The capstan bearing according to claim 1, wherein the capstan bearing is integrally formed with a chassis provided with the capstan bearing by a synthetic resin. 3. One of the two mutually different positions along the longitudinal direction of the capstan is located on the side that is pressed by the pinch roller in the circumferential direction of the capstan, and the other is the side that is pressed by the pinch roller. Is located on the opposite side, and the contact area of the other side is larger than the contact area of the other side with respect to the capstan. 3. The capstan bearing according to claim 1 or 2, wherein