JPS58191321A - Bearing - Google Patents

Abstract

PURPOSE:To improve bearing characteristics in a high temperature and humidity condition or in a low temperature by providing a slide bearing bush formed of a high-polymer material to which at least a kind of pulverized powder among MoS2, graphite and BN is added at 5-60wt%. CONSTITUTION:In a bearing for a shutter screen of a focal-plane shutter in a camera, a shutter screen rotary shaft 2 is rotatably mounted on a fixing base plate 3 through a bearing 1. The bearing 1 is formed of a high-polymer material to which at least a kind of pulverized powder among MoS2, C (graphite) and BN is added at 5-60wt%. As a high-polymer material, used is a thermosetting resin such as an epoxy resin or the like, or a thermoplastic resin such as a polyethylene resin or the like. A slide bearing formed of the above material provides a good lubrication even in a high temperature and humidity condition or in a low temperature condition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bearing suitable for use as a sliding bearing for supporting the front and rear curtain shafts of a focal plane shutter mechanism of a camera, for example.

Conventionally, the bearings used in the focal plane shutter mechanism of cameras are porous oil-impregnated bearings, which are oil-less bearings that require fewer lubrications due to the difficulty of lubricating them. , #II It had the disadvantage that oil becomes difficult to seep out at high humidity and low temperatures, making it difficult for the shaft to rotate smoothly, and as a result, the shutter speed becomes unstable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bearing that can avoid the drawbacks of unstable shutter speeds at high humidity and low temperatures caused by the conventional porous oil-impregnated bearings.

In the bearing of the present invention, the contact portion with the shaft to be supported is formed by adding fine powder of at least one of Mo82, C (Graphai), and BN to the molecular material at a weight ratio of 5 to bO-. It is characterized by being formed from a composition consisting of: .

The above molecular materials include thermosetting resins such as epoxy resins, noaryl phthalate resins, polyethylene terephthalate resins, polyester resins, furan resins, mequin street resins, thunol resins, polyamide resins, and polyester resins. Or modified substances thereof, or thermoplastic resins such as cellulose, /IJ styrene resin, polyvinyl chloride resin, I-dimethyl methacrylate resin, I-liquor nate resin, 4-lyacetal resin, etc. Polyethylene resin, polynolopyrene resin, 4-reaod resin, MuB8 resin,
Fluororesin (PTFE), polyphenylene oxide resin (PPO), or modified substances thereof can be used.

Bearings whose contact parts with the shaft are formed using the above composition have much better lubrication than conventional porous oil-impregnated bearings, which cause oil oozing and worsening, even at high temperatures, high humidity, or low temperatures. It has been found that when used as a bearing for the shutter curtain shaft of a camera, the instability of shutter speed can be greatly reduced and shutter accuracy can be improved.

In the present invention, CXBN or FiMo 8 in the polymer material
The reason why the amount of fine powder in No. 2 is set at a weight ratio of 5 to 60 is that if it is less than 5%, the above purpose cannot be achieved, and if it exceeds 60%, the resin viscosity will be extremely high and molding will be difficult. It's for a reason.

An example of a specific form of a bearing according to the present invention is shown in the drawings. 1st
The figure shows the shutter curtain bearing of a focal gray 7 shutter of a general camera for reference.
2 is a bearing, 2 is a shutter curtain rotating shaft, and 3 is a mounting board. As an embodiment of the present invention, the bearing 1 in FIG. 1 may be formed entirely of the above-mentioned composition (FIG. 2), or only the portion 5 of the bearing 1 that is attached to the shaft may be formed of the above-mentioned composition. (
(Fig. 3). In addition, in the figure, 4 is a shaft hole.

Hereinafter, the effects of the present invention will be explained by showing examples.

As a comparative example, a conventional porous oil-impregnated bearing was used, and as an example of the present invention, C (graphite) was added in a weight ratio of epoxy resin, which is a thermosetting resin as a polymer material.*59
Bearings formed in the shape shown in Fig. 2 using four types of compositions containing 120% and 40-160% of the above were respectively attached to an eye reflex camera with a focal plane shutter as shown in Fig. 1. After confirming the shutter accuracy at a shunter speed of 1000 seconds, ■ As a high temperature and high humidity test, we left the shutter charged for 4 hours in an air with a temperature of 45 degrees Celsius and a humidity of 85 degrees Celsius, and fired the first shot after mourning. ”/1000
Measuring shutter accuracy at shutter speeds of seconds,
In addition, as a low-temperature test, the first shot "710" after leaving the shutter open for 4 hours in air at -20℃.
The shutter accuracy at 00 seconds was measured. The exposure time and exposure unevenness in the cases (1) and (2) above are as shown in the table below.90 The exposure time and exposure unevenness in the above cases are as follows.

1. Exposure time: The error in the exposure time was calculated by dividing the actual exposure time v2 by the reference value V and fitting it with a logarithm with the base of 2, and EV was used as the unit of the value Δ. In other words, mI is the reference value, and QE with a large deviation from it
The V value increases. In addition, the EV value of the above-mentioned fit tml@e
If you rewrite it yourself, you will get the following passage.

2. Exposure time unevenness (abbreviated as exposure unevenness in the table above):
In the above experiment, the obtained shutter speed value at the center of the screen divided by the shutter speed value at the end of the screen is expressed as a logarithm with a base of 2, and the maximum absolute value is t - output time. expressed.

As is clear from the above table, it was found that bearings for Kamef/Yanotar made of epoxy resin with graite added in the respective ratios had significantly improved shutter accuracy at high temperature, high humidity, or low temperature.

Similar effects can be expected when MO82 and BN t-, which are solid repellents, are used in addition to C (graphite) as a substance added to the molecular material.

As explained above, when the bearing according to the present invention is used as a shutter curtain bearing for a camera, smooth rotation of the first shaft of the shutter is prevented due to deterioration of oil leakage at high temperature and high humidity or low temperature. It does not have the drawback of conventional porous oil-impregnated bearings, such as poor accuracy, and allows accurate estimation of shutter performance.

The bearing according to the present invention can be used not only as a bearing for a naori shutter but also as a general sliding bearing.

[Brief explanation of drawings]

Figure 1 is a sectional view of the camera shaft bearing structure, Figure 2 is
The figure generally shows an example of the form of a camera shutter curtain bearing embodying the present invention, and FIG. 3 is a diagram showing another example of the camera shutter curtain bearing embodying the present invention. l: Bearing, 2: Shaft, 3: Substrate, 4: Shaft hole, 5: Contact part with shaft. -12″. Figure 1 Figure 2 Figure 3

Claims (3)

[Claims] (1) The contact part with the shaft to be supported is made of Me in a polymer material.
A bearing characterized in that it is formed from a composition in which at least one fine powder of S2, C (graphite), and BNO is added at a weight ratio of 5 to 60. (2) The bearing according to item 1, wherein the polymer material is a thermosetting resin. (3) The bearing according to Paragraph 1 of Section 1i28, when the polymeric material is a thermoplastic resin.