JPH11335571A - Oil-impregnated resin composition and oil-impregnated resin bearing using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a function having a smooth surface, a function of preventing an increase in sliding resistance due to intrusion of fine powder such as toner, and a high mechanical strength for use under high load and high speed conditions. To provide an oil-impregnated resin composition for a bearing and an oil-impregnated resin bearing 1 using the oil-impregnated resin composition. An oil-containing resin bearing is formed using an oil-containing resin composition containing a lubricating oil, a polynorbornene-based elastomer as a lubricating oil carrier, a zinc oxide whisker as a reinforcing filler, and a polyacetal as a self-lubricating resin. . This oil-impregnated resin bearing 1 has high strength due to the reinforcing effect of zinc oxide whiskers. Further, since the surface smoothness of the sliding portion 2 is high and the surface hardness is low, the friction and wear characteristics are also excellent. It is preferable that a metal powder is blended as another reinforcing filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-containing resin composition used for a sliding member of an electrophotographic apparatus such as a copying machine, a printer and a facsimile, and an oil-containing resin bearing using the oil-containing resin composition.

[0002]

2. Description of the Related Art A self-lubricating engineering plastic having a low coefficient of friction is used as a supporting and sliding member for a movable portion of an electrophotographic apparatus using a toner with a low friction coefficient for the purpose of reducing the weight and size and simplifying maintenance and inspection such as lubrication. Oil-free bearings are widely used. In addition, as an improvement of such a bearing, a very flexible resin such as polynorbornene resin is mixed with a plastic composition as a lubricating oil carrier, and the lubricating oil is carried on this to allow the lubricating oil to ooze to the sliding portion. In addition, there has been proposed a device in which friction and wear characteristics are improved (for example, Japanese Patent Application Laid-Open No. 56-47495).
Reference). In this bearing, even if the fine powder penetrates into the sliding part by being used in the part where the fine powder such as toner exists,
Since the fine powder is taken in and buried in the sliding surface of the bearing, it is possible to effectively prevent an increase in sliding resistance.
Further, a bearing has been proposed in which dimensional accuracy is improved by blending a metal powder and thermal conductivity is improved to prevent the toner from melting (for example, Japanese Patent Publication No. 7-30).
347).

[0003]

However, since the soft resin and metal powder contained in these bearings exist as foreign substances in the matrix, so to speak, a reduction in the mechanical strength of the bearing itself is inevitable. It becomes brittle and easily broken. Therefore, there is an inconvenience that it is not suitable for use in a high-load, high-speed region.

[0004] Reinforcing fibers such as glass fiber and carbon fiber,
Means for compensating for a decrease in the mechanical strength of these bearings by adding a reinforcing filler such as whiskers may be considered.
However, the addition of a reinforcing fiber, a reinforcing filler, or the like causes a decrease in smoothness of a sliding portion, thereby increasing the wear amount of the shaft member. Further, since the hardness of the bearing increases due to the addition of the reinforcing fiber, the reinforcing filler, or the like, there is a problem that the sliding resistance is increased due to the intrusion of the fine powder such as the toner and the rotational torque of the shaft is increased. .

The present invention has been made in view of these problems, has a smooth surface, has a function of preventing an increase in sliding resistance due to intrusion of fine powder such as toner, and has a mechanical strength. It is an object of the present invention to provide an oil-impregnated resin composition for a sliding portion such as a bearing and an oil-impregnated resin bearing using the oil-impregnated resin composition, which can be used under high load and high speed conditions. It is.

[0006]

Means for Solving the Problems The present invention made to solve the above-mentioned problems is directed to an oil-containing resin composition containing a lubricating oil, a lubricating oil carrier, a reinforcing filler and a self-lubricating resin. An oil-containing resin composition using zinc oxide whiskers (claim 1).

When an oil-impregnated resin bearing is formed using this oil-impregnated resin composition (claim 5), the zinc oxide whisker is used as a reinforcing filler in the oil-impregnated resin composition. And the mechanical properties of the oil-impregnated resin bearing can be improved. The zinc oxide whiskers do not deteriorate the smoothness of the sliding portion. Furthermore, since zinc oxide whiskers do not significantly increase the surface hardness of the oil-impregnated resin bearing as compared with general reinforcing fibers or reinforcing fillers, they maintain the function of preventing the increase in sliding resistance due to penetration of fine powder such as toner. be able to.

[0008] Zinc oxide whiskers have a fiber length of 2
Those having a fiber diameter of from 0.2 μm to 50 μm and a fiber diameter of from 0.2 μm to 3 μm are preferably used.

In the present invention, if a zinc oxide whisker and a metal powder are used in combination as a reinforcing filler and the volume ratio of the zinc oxide whisker to the metal powder is set to 4/6 or more and 6/4 or less, the oil-impregnated resin bearing can be obtained. Thermal conductivity and dimensional stability can be improved (claim 2).

In these inventions, in order to achieve both a reinforcing effect and an effect of preventing an increase in sliding resistance, the content of the reinforcing filler is 0.5% by volume to 100% by volume of the oil-containing resin composition.
It is preferable that the content be not less than 40% by volume (claim 3).

The coefficient of friction of the sliding portion of the oil-impregnated resin bearing thus obtained is 0.20 or less, and the limit PV value is 700.
kgf / cm ² · m / min or more, which is preferable (claim 6).

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing an oil-impregnated resin bearing 1 according to one embodiment of the present invention. The oil-impregnated resin bearing 1 has a substantially cylindrical shape, and its inner wall is a sliding portion 2 that slides on a shaft member.

This oil-impregnated resin bearing 1 is molded from an oil-impregnated resin composition containing polyacetal as a main polymer as a self-lubricating resin. The self-lubricating resin is a resin which has lubricity even when a solid or liquid lubricant is not added and has a relatively low friction coefficient. As the self-lubricating resin applicable to the oil-impregnated resin bearing 1, in addition to the above-mentioned polyacetal, for example, polyolefin resins such as polyethylene and polypropylene, polyamide, polyethylene terephthalate, polybutylene terephthalate, polytetrafluoroethylene and the like can be mentioned.

The amount of the self-lubricating resin in the oil-containing resin composition is preferably 40% by volume or more and 98% by volume or less.
Particularly preferred is 5% by volume to 85% by volume. If the amount of the self-lubricating resin is less than the above range, the mechanical strength required as a sliding member decreases, and the amount of wear may increase. Conversely, if the amount of the self-lubricating resin exceeds the above range, the hardness of the oil-containing resin composition increases, and the sliding resistance may increase due to the penetration of fine powder such as toner.

The oil-containing resin bearing 1 contains a lubricating oil. By doing so, the lubricating oil seeps into the sliding portion 2 during use, and the sliding friction resistance between the oil-containing resin bearing 1 and the shaft material is reduced. Therefore, the oil-containing resin bearing 1 can be continuously used without lubrication. The amount of the lubricating oil is from 1% by volume to 40% by volume based on 100% by volume of the oil-containing resin composition used.
It is preferably at most 10% by volume, particularly preferably at least 10% by volume and at most 30% by volume. If the amount is less than the above range, the sliding friction resistance may not be sufficiently reduced. Conversely, if the compounding amount exceeds the above range, excessive lubricating oil oozes out into the sliding portion 2 and the fine powder such as toner intervening on the sliding surface tends to solidify, thereby increasing the sliding resistance. There is.

As the lubricating oil to be used, any lubricating oil that is generally used as a lubricating oil may be used. For example, (a) aromatic lubricating oils such as spindle oil, turbine oil, machine oil, and dynamo oil; (B) naphthenic lubricating oil,
(C) paraffin-based lubricating oils, and (d) synthetic oils such as hydrocarbons, esters, polyglycols, and silicones.

The oil-impregnated resin bearing 1 contains a polynoribone-based elastomer as a lubricating oil carrier. By doing so, the polynoribone-based elastomer absorbs the lubricating oil, so that a large amount of the lubricating oil can be contained in the oil-impregnated resin bearing 1 and that the amount of the lubricating oil that oozes out on the sliding surface can be stabilized. Become like The blending amount of the polynoribone-based elastomer is preferably from 0.1% by volume to 20% by volume, particularly preferably from 5% by volume to 15% by volume, based on 100% by volume of the oil-containing resin composition used. If the amount is less than the above range, it may not be possible to mix a large amount of lubricating oil into the oil-containing resin bearing 1. Conversely, if the compounding amount exceeds the above range, the properties of the self-lubricating resin which is the main polymer will be lost, for example, the mechanical strength of the oil-impregnated resin bearing 1 will decrease, or the heat resistance will decrease. Sometimes.

The lubricating oil carrier applicable to the oil-containing resin bearing 1 may be, for example, butadiene rubber, isoprene rubber, EPD, in addition to the above-mentioned polynoribone-based elastomer.
M, styrene butadiene rubber and the like. Among these lubricating oil carriers, a polynoribone-based elastomer is preferred, which has a porous structure and thus has a high lubricating oil absorption capacity, and therefore requires a small amount of contaminant to exhibit a predetermined lubricating ability.

The oil-containing resin bearing 1 contains zinc oxide whiskers as a reinforcing filler. Here, a zinc oxide whisker is a fine single crystal mainly composed of zinc oxide. By incorporating zinc oxide whiskers, the oil-impregnated resin bearing 1 is reinforced, and high mechanical strength can be obtained even for the oil-impregnated resin bearing 1 in which foreign substances such as a lubricating oil carrier are present.

Since zinc oxide whiskers are fine short fibers and have a tetrapod-like crystal structure, even if they are blended, the smoothness of the sliding portion 2 of the oil-impregnated resin bearing 1 can be deteriorated. Therefore, the amount of wear of the shaft member can be suppressed. In addition, zinc oxide whiskers do not increase the surface hardness of the oil-impregnated resin bearing 1 much compared to general reinforcing fibers or reinforcing fillers, probably because of the low surface hardness of the whiskers themselves. Therefore, the toner or the like that has entered the sliding portion 2 is taken into the inside, and it is possible to effectively prevent the sliding friction resistance of the sliding portion 2 from increasing.

The fiber length of the zinc oxide whiskers is preferably 2 μm or more and 50 μm or less, particularly preferably 30 μm or more and 40 μm or less. If the fiber length is less than the above range, a sufficient reinforcing effect cannot be obtained, resulting in insufficient mechanical strength or increased wear. Conversely, if the fiber length exceeds the above range, the surface smoothness of the sliding portion 2 may be impaired.

The fiber diameter of zinc oxide whiskers is 0.2 μm
Not less than 3 μm and preferably not less than 0.5 μm and 2.5 μm
The following are particularly preferred. If the fiber diameter is less than the above range,
The reinforcing effect may be insufficient and the strength of the oil-containing resin bearing 1 may be reduced. Conversely, if the fiber diameter exceeds the above range, the surface smoothness of the sliding portion 2 may be impaired.

The oil-impregnated resin bearing 1 may be constituted by using a metal powder as another reinforcing filler together with the zinc oxide whisker. Since a metal generally has higher thermal conductivity than a polymer, the thermal conductivity of the oil-containing resin bearing 1 can be increased by blending the metal powder. Therefore, the temperature rise of the sliding portion 2 during operation can be suppressed, and the melting of the entering toner can be prevented. Also, by blending the metal powder, the coefficient of thermal expansion of the oil-impregnated resin bearing 1 can be reduced, and the oil-impregnated resin bearing 1 having excellent dimensional stability, which is an extremely important physical property as a bearing, can be obtained.

As the metal material used for the metal powder,
For example, copper-based metals such as bronze, phosphor bronze, white metal, lead bronze, and kelmet (copper-lead alloy), which are excellent in wear resistance, may be used.

When zinc oxide whiskers and metal powders are used in combination, the volume ratio is preferably from 4/6 to 6/4. If the volume ratio is less than the above range, the surface smoothness of the sliding portion 2 may be impaired. Conversely, if the volume ratio exceeds the above range, the thermal conductivity and dimensional stability of the oil-impregnated resin bearing 1 may decrease.

The total content of these reinforcing fillers is 0.5% by volume with respect to 100% by volume of the oil-containing resin composition used.
It is preferably from 40% by volume to 40% by volume, and particularly preferably from 10% by volume to 30% by volume. If the content is less than the above range, the strength of the oil-containing resin bearing 1 may be insufficient or the thermal conductivity may be reduced. Conversely, if the content exceeds the above range, the oil-impregnated resin bearing 1 may be embrittled or the surface smoothness of the sliding portion 2 may be reduced.

The coefficient of friction of the sliding portion 2 of the oil-containing resin bearing 1 is preferably 0.20 or less, particularly preferably 0.15 or less. If the friction coefficient exceeds the above range, the degree of abrasion of the shaft member may increase. Since the smaller the friction coefficient is, the smaller the friction coefficient is, the lower limit of the friction coefficient is not particularly set in the present invention. Here, the friction coefficient is defined as S45C
(No quenching) Load 5kgf, Sliding speed 1
It means the coefficient of friction at 1.3 m / sec.

The limit P of the sliding portion 2 of the oil-containing resin bearing 1
V value is preferably not less than ^{700kgf / cm 2 · m / min} , 800kgf / cm 2 · m / min or more is particularly preferable. If the limit PV value is less than the above range, a high load
Under high speed conditions, the sliding portion 2 may be melted by frictional heat. Since the larger the limit PV value is, the more preferable it is, the present invention does not particularly set the upper limit of the limit PV value, but the upper limit of the generally obtained limit PV value is 1000 kg.
It is about f / cm ² · m / min. Here, the limit PV value means a product of the load P and the speed V at a point where the sliding portion 2 melts due to frictional heat and the friction coefficient and wear increase rapidly.

The oil-impregnated resin composition used in the oil-impregnated resin bearing 1 is prepared, for example, by mixing a lubricating oil carrier and a lubricating oil to prepare a muddy material in which both are uniformly dissolved, and powdery self-lubricating material. It is obtained by adding a water-soluble resin and zinc oxide whiskers and mixing them. When molding the oil-impregnated resin bearing 1 from this oil-impregnated resin composition, various known molding methods can be employed, but generally, an injection molding method is employed.

The oil-impregnated resin composition used in the oil-impregnated resin bearing 1 includes, in addition to the aforementioned lubricating oil, lubricating oil carrier, reinforcing filler and self-lubricating resin, if necessary, for example, an ultraviolet absorber, An inhibitor, a colorant, an antistatic agent, a flame retardant and the like can be added.

[0032]

Hereinafter, the present invention will be described in detail with reference to Examples.
Of course, the present invention should not be construed as being limited based on the description of this embodiment.

Example 1 8% by volume of a polynorbornene-based elastomer (trade name "Norsolex" of Nippon Zeon Co., Ltd.) as a lubricating oil carrier and a mineral oil (trade name "Dafney" of Idemitsu Oil Co., Ltd.) as a lubricating oil Super Mechanic Oil 100 ") and 30% by volume were mixed with a Henschel mixer and allowed to stand at room temperature for 12 hours to obtain a mud-like mixture in which both were uniformly compatible. 42% by volume of a polyacetal resin powder (trade name “DURACON M90-02” of Polyplastics Co., Ltd.) as a self-lubricating resin
And 20% by volume of zinc oxide whiskers (trade name “Panatetra” of Matsushita Amtech Co., Ltd.) were added and mixed again with a Henschel mixer to obtain an oil-containing resin composition.

The oil-containing resin composition is extruded and cut,
A resin pellet was obtained. Then, injection molding is performed using the resin pellet, and the outer diameter (indicated by D in FIG. 1) is 12
The oil-impregnated resin bearing of Example 1 having an mm, an inner diameter (indicated by d in FIG. 1) of 6 mm, and a length (indicated by L in FIG. 1) of 4 mm was obtained.

Example 2 The procedure of Example 1 was repeated except that the blending amount of zinc oxide whiskers was 10% by volume, and 10% by volume of kelmet powder (manufactured by Fukuyama Metal Foil Co.) as another reinforcing filler was blended. Thus, an oil-impregnated resin bearing of Example 2 was obtained.

[Comparative Examples 1 to 4] The blending amount of mineral oil was 20
% By volume, no polynorbornene-based elastomer and zinc oxide whiskers were blended at all, and the blending amount of the polyacetal resin was 80% by volume.
An oil-impregnated resin bearing of Comparative Example 1 was obtained.

The amount of the mineral oil was 8% by volume, the amount of the polynorbornene-based elastomer was 5% by volume, no zinc oxide whiskers were mixed, 30% by volume of kelmet powder was mixed, and the polyacetal resin was mixed. Comparative Example 2 was performed in the same manner as in Example 1 except that the blending amount was 57% by volume.
An oil-impregnated resin bearing was obtained.

An oil-impregnated resin bearing of Comparative Example 3 was obtained in the same manner as in Example 1, except that 10% by volume of kelmet powder and 10% by volume of glass fiber were mixed without any zinc oxide whiskers. Was.

Also, no zinc oxide whiskers were added, 10% by volume of kelmet powder was added, and 10% by volume of potassium titanate whisker (trade name "Toficar Y" of Nihon Whisker Co.), which is a needle-like crystal, was added. Other than the above, an oil-impregnated resin bearing of Comparative Example 4 was obtained in the same manner as in Example 1.

Reference Examples 1 and 2 For comparison with the oil-impregnated resin bearing of the present invention, a commercially available oil-impregnated bearing made of a porous sintered body was prepared and referred to as Reference Example 1. In addition, a commercially available rolling bearing using a metal bearing was prepared as Reference Example 2.

[Evaluation of Bearing Characteristics] First, the surface smoothness (tactile sensation) and surface hardness (Shore D) of the oil-impregnated resin bearings of Examples and Comparative Examples were measured. These results are shown in Table 1 below.

Next, the sliding characteristics of the bearings of the respective examples, comparative examples and reference examples were evaluated using a test device shown in FIG. In this test apparatus, the shaft 4 is connected to the motor 3. The material of the shaft 4 is S45C (no quenching), and its surface roughness is 3S. The shaft 4 is inserted into the box 5. The lower part of the box 5 has a bearing 6 for evaluation.
The shaft 6 is received by the bearing 6. The upper part of the box 5 is a toner chamber 7 in which a two-component toner 8 is stored. A weight 9 is connected to the box 7 via a string-shaped body 11, and the weight 9 causes the box 7 to receive a load in a direction indicated by an arrow A. Since the box 7 is supported by the rollers 10, an equivalent load is applied between the shaft 4 and the bearing 6.

In this evaluation, the load of the shaft 4 was 5 kgf,
Under a condition of a rotation speed of 600 rpm for 48 hours. Then, the sliding resistance (motor current value) 24 hours after the start of operation, the amount of wear of the bearing 6 at the end of operation (the amount of increase in inner diameter), and the temperature increase of the bearing 6 from the start of operation to the end of operation are shown. It was measured. These results are shown in Table 1 below.

[0044]

[Table 1]

In Table 1, the oil-impregnated resin bearings of Examples 1 and 2 using zinc oxide whiskers were Comparative Example 2 using only kelmet powder, Comparative Example 3 using kelmet powder and glass fiber in combination, and It has better surface smoothness and lower surface hardness than the oil-impregnated resin bearing of Comparative Example 4 in which kermet powder and potassium titanate whisker are used in combination.
Therefore, the sliding resistance is small, the amount of wear of the sliding portion is small, and the temperature rise due to operation is small. In particular, the sliding resistance is lower than that of the rolling bearing of Reference Example 2, but is at a level comparable to that of the oil-impregnated bearing using the porous sintered body of Reference Example 1.

The oil-impregnated resin bearing of Comparative Example 1 does not contain a lubricating oil carrier, and therefore has a high surface hardness, so that the temperature of the sliding portion is significantly increased, and the lubricating oil oozes out. The toner that has entered the sliding part melts and solidifies,
The motor stopped rotating and could not be evaluated.

The oil-impregnated resin bearing of the first embodiment and the oil-impregnated resin bearing of the second embodiment
In comparison with the oil-impregnated resin bearing of Example 2, Example 2 in which metal powder and zinc oxide whiskers were used in combination as a reinforcing filler was more effective than Example 1 in which only zinc oxide whiskers were used.
Good results were obtained in terms of the sliding resistance, the amount of wear, and the temperature rise. Among them, the reason why the rising temperature of Example 2 was suppressed to be low was to improve the thermal conductivity by the metal powder, and the sliding resistance and the amount of wear were small because the spreadability of the lubricating oil was originally small. It is considered that the spreadability of the lubricating oil is imparted to the bearing surface by the metal powder, and the slidability is also improved.

The present invention has been described above by taking as an example the case where the toner powder is used for a bearing of an electrophotographic apparatus in which the toner powder is interposed. However, the oil-containing resin composition of the present invention can be used in any case where strength and friction / wear characteristics are required. It can be used as a material for members.

[0049]

As described above, according to the present invention,
Oil-impregnated with excellent surface smoothness, despite its increased mechanical strength due to reinforcement, and with a low surface hardness that prevents the sliding resistance from increasing due to penetration of fine powder such as toner. A resin bearing can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an oil-containing resin bearing according to an embodiment of the present invention.

FIG. 2 is a front view schematically showing a test apparatus for evaluating the effect of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oil-impregnated resin bearing 2 ... Sliding part 3 ... Motor 4 ... Shaft 5 ... Box 6 ... Bearing 7 ... Toner chamber 8 ... Toner 9 ... Weight 10 ・ ・ ・ Roller 11 ・ ・ ・ String

Claims (6)

[Claims] 1. An oil-containing resin composition comprising a lubricating oil, a lubricating oil carrier, a reinforcing filler and a self-lubricating resin, wherein zinc oxide whiskers are used as the reinforcing filler. 2. The method according to claim 1, wherein zinc oxide whiskers and metal powder are used as the reinforcing filler, and a volume ratio between the zinc oxide whiskers and metal powder is 4/6 or more and 6/4 or less. An oil-containing resin composition. 3. The content of the reinforcing filler is 0.5% by volume or more and 40% by volume with respect to 100% by volume of the oil-containing resin composition.
The oil-containing resin composition according to claim 1, wherein: 4. The fiber length of the zinc oxide whiskers is 2 μm.
m or more and 50 μm or less, and the fiber diameter is 0.2 μm or more and 3 or more.
The oil-containing resin composition according to any one of claims 1 to 3, wherein the composition is not more than μm. 5. An oil-impregnated resin bearing installed in a portion of an electrophotographic apparatus where toner powder is present, wherein the oil-impregnated resin composition according to claim 1 is used as a material. Features oil-impregnated resin bearings. 6. The sliding part has a friction coefficient of 0.20 or less and a limit PV value of 700 kgf / cm ² · m / min.
The oil-impregnated resin bearing according to claim 5, which is as described above.