JPS6150205A - Cylinder device for fluid bearing - Google Patents

Abstract

PURPOSE:To prevent the stack of foreign matters or the wear powder and to ensure the normal revolutions of a cylinder device for fluid bearing, by providing a deformed herringbone type group at a fixed side of a shaft or a sleeve with the middle folded parts of each group having a wedge shape set with a shaft given from the same circumference of a circle. CONSTITUTION:A deformed herringbone type group 14 is provided at two areas on the vertical outer circumferential surface of the core of a fixed shaft 12 with the middle folded parts 13a of each group 13 of a wedge shape shifted alternately toward the axial core from the same circumference of a circle. When a rotary part including a sleeve is revolved, a cylinder device can keep normal revolutions with centripetalism secured by a pumping function. The foreign matters or the wear powder staying at a mixmum pressure generating part are ejected out toward the side of low pressure with evolutions since the parts 13a are set with mutual shifts secured toward the axial core. This prevents a burning fault to maintain the normal revolutions of a cylinder device for fluid bearing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fluid bearing cylinder device used in video tape recorders and the like.

Conventional configuration and its problems FIG. 3 is a sectional view of a conventional hydrodynamic bearing cylinder device.

Figure 4 (a) is an enlarged view of the main part, Figure 4 (b) is Figure 4 (
It is a pressure distribution diagram at the intermediate bending part of (a).

In Fig. 3, (1) is a fixed cylinder that guides the magnetic tape, (2) is a fixed cylinder that guides the magnetic tape, and (2) is an intermediate bent part (3a) of each group (3) on the same circumference at two places on the upper and lower outer peripheral surface in the axial direction. It is a fixed shaft having a bellingbone type group (4) arranged therein, and is press-fitted coaxially into the center of the fixed cylinder (1). (5) is a sleeve that is rotatable coaxially with the fixed shaft (2) and has a shaft shaft P (6) at a position opposite to the herringbone group (4); (7) is a sleeve that is rotatable coaxially with the fixed shaft (2); ) and the inner surface of the bearing (6).

The operation of the hydrodynamic bearing cylinder device configured as described above will be described below. When the rotating part including the sleeve (5) of this hydrodynamic bearing cylinder device rotates, the herringbone type group (4), the bearing inner diameter surface (6), and the lubricant (
The pumping action of the radial bearing constituted by 7) maintains the centripetal nature and maintains normal rotation.

However, in the above-mentioned configuration, each group (3) of the herringbone group (4) has an intermediate bend (3).
3a) has a rounded shape rather than an acute angle microscopically due to processing limitations. As a result, as shown in FIG. 2, the entire pressure distribution becomes flat at the maximum pressure generating portion (8). For this reason, foreign matter that is initially contained in the bearing part, which is made up of the herringbone group (4), the inner surface of the bearing (6) of the sleeve (5), and the lubricant (7), and the occurrence of foreign matter when starting or stopping rotation. If the wear powder exists in this flat maximum pressure generating part (8), it will not move elsewhere because the pressure gradient is small.
It rotates on the circumference of this maximum pressure generating part (8), and as this phenomenon progresses, the lubricant (7) is expelled from the bearing part, accumulates, and eventually seizes and becomes unable to rotate. had.

OBJECT OF THE INVENTION The object of the present invention was to solve the above-mentioned conventional drawbacks, and to provide a hydrodynamic bearing cylinder device that prevents the accumulation of foreign matter and abrasion powder on the bearing part and maintains normal rotation. The purpose is to provide the following.

Structure of the Invention The present invention comprises a shaft, a sleeve provided coaxially with the shaft, and a lubricant interposed in a minute gap between the shaft and the sleeve, and the lubricant is interposed in a minute gap between the shaft and the sleeve. On the fixed side defined on one side.

This is a modified herringbone type group in which the intermediate bent portions of each wedge-shaped group are staggered from the same circumference, which prevents the accumulation of foreign matter and wear particles and maintains normal rotation. It is something that can be done.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the main parts of the hydrodynamic bearing cylinder device according to the present invention, FIG. 1(a) is a plan view of a modified herringbone type group provided on the outer peripheral surface of the shaft, and FIG. It is a pressure distribution diagram at the intermediate bending part of figure (a). Fig. 2 shows another embodiment of the present invention, Fig. 2(a) is a plan view of a modified herringbone type group provided on the outer peripheral surface of the shaft, Fig. 2(b)
) is a pressure distribution diagram at the intermediate bending portion in FIG. 2(a).

The basic configuration of the hydrodynamic bearing cylinder device according to the present invention is the same as that shown in FIG. 3 except for the herringbone type group (4), and the same symbols are used for the same members.

In Figures 1 and 3, (12) is the fixed cylinder (1
) is coaxially press-fitted into the center of the fixed shaft (12), and the intermediate bent portion (13a) of each of the five wedge-shaped groups (13) is located at two locations on the upper and lower outer circumferential surfaces of the fixed shaft (12) in the fine direction. Deformed herringbone type groups (14) are provided which are arranged alternately shifted in the axial direction from the same circumference, and the herringbone type groups (14) and the groups (14) opposite to the modified herringbone type groups (14) are provided. Bearing inner surface (6) of sleeve (5)
The bearing portion is constituted by the lubricant (7) interposed in the minute gap between the two.

The operation of the hydrodynamic bearing cylinder device configured as described above will be described below. When the rotating part including the sleeve rotates, it maintains centripetal movement due to pumping action.
This also holds true for this modified herringbone type group (14) and maintains normal rotation. Then, the middle corner (13a
) are arranged alternately in the microscopic direction, so that foreign matter and wear particles existing in the maximum pressure generating part (18a) are transferred to the next group (13) where the pressure gradient is steep (19c),
In addition, foreign matter and wear particles existing in the maximum pressure generation part (18b) are removed from the next group (13) where the pressure gradient is steep (19d).
), at which point it is removed to the side with lower pressure. Therefore, foreign matter and wear particles do not accumulate on the group part, preventing seizure.

FIG. 2 shows another embodiment of the present invention, in which modified herringbone type groups are provided at two locations on the upper and lower outer circumferential surfaces of the fixed shaft (22) coaxially press-fitted into the center of the fixed cylinder. (24) represents each wedge-shaped group (2
The intermediate bent portion (23a) of 3) is arranged in a sin curve shape on the circumference, as shown by the dashed line in FIG. 2(a).

The operation of the hydrodynamic bearing cylinder device configured as described above will be described below. When the rotating part including the sleeve rotates, the centripetal property is maintained by the pumping action, which also holds true for this modified herringbone type group (24), and normal rotation is maintained. Since the intermediate bent portions (23a) of each group are arranged in a sin curve shape, the pressure distribution at the intermediate bent portions (23a) is as shown in Fig. 2(b).
), the foreign matter and wear particles existing in the maximum pressure generating part (28) are moved to the part where the pressure gradient is steep due to rotation, and at that point are removed to the part where the pressure is lower. Therefore, foreign matter and wear particles do not accumulate on the group part, preventing seizure.

Effect of invention, Jul! 1521'DL,=7'J:'
>'kZ, *! IIJH::! t+, If, 11
11m: Foreign matter existing in 2gB from the beginning and rotation start-up
It is possible to prevent the build-up of abrasion powder generated by the stoppage and prevent seizure, thereby maintaining the normal rotation of the fluid bearing cylinder device.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view of a modified herringbone type group provided on the outer peripheral surface of the shaft, and FIG. 1(b) is a plan view of a modified herringbone type group provided on the outer peripheral surface of the shaft. Figure (a
) is a pressure distribution diagram of the intermediate bending part. FIG. 2 shows another embodiment of the present invention, FIG. 2(a) is a plan view of a modified herringbone type group provided on the outer peripheral surface of the shaft, and FIG. 2(b) is a plan view of a modified herringbone type group provided on the outer peripheral surface of the shaft. A pressure distribution diagram of the intermediate bending part in one column, Figures 3 and 4 show a conventional hydrodynamic bearing cylinder device, Figure 3 is a cross-sectional view thereof, Figure 4 (a) is an enlarged view of the main part, FIG. 4(b) is a pressure distribution diagram at the intermediate bent portion in FIG. 4(a). (12) (22)...axis, (13) (23)・
... Group, (13a) (23a) ... Intermediate bent part, (14) (24) ... Modified herringbone type group, (5) ... Sleeve, (7) ... Lubrication 41 substitute Yoshihiro Morimoto Figure 1 (N?N Figure 2 and -2) tsB Figure Figure 4

Claims (1)

[Claims] 1. Consisting of a shaft, a sleeve provided coaxially with the shaft, and a lubricant interposed in a minute gap between the shaft and the sleeve, either the shaft or the sleeve. A hydrodynamic bearing cylinder device provided with a modified herringbone group on one fixed side, in which the wedge-shaped intermediate bent portions of each group are arranged offset from the same circumference. 2. The hydrodynamic bearing cylinder device according to claim 1, wherein the modified herringbone type groups are arranged such that their intermediate bent portions are alternately shifted on the circumference. 3. The hydrodynamic bearing cylinder device according to claim 1, wherein the modified herringbone type group has an intermediate bent portion arranged in a sin curve shape on the circumference.