JPH05296232A - Guide roller for timing belt - Google Patents

Abstract

PURPOSE:To provide a timing belt guide roller which can prevent the occurrence of a shocking foreign sound and can reduce the number of parts. CONSTITUTION:One end of a fitting material 2 is fixed on an engine 1 by means of a bolt 3, and a fulcrum axis bolt 4 is fitted to the other end side of the fitting material 2, and a free rotary body 5 consisting of a lubricous rubber composite is rotatably provided at this fulcrum axis bolt 4. The combination of the lubricous rubber composite is made up of thermoplastic fluororesin as a first indispensable element, fluoric rubber as a second indispensable element and a fluoric polymer of a low molecular weight as a third indispensable element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a timing belt guide roller, and more particularly to a timing belt guide roller for guiding a timing belt used in a valve operating system for power of an engine or the like.

[0002]

2. Description of the Related Art The inventor of the present application has proposed a timing belt damping device in Japanese Patent Application No. 3-304857. In this damping device, a free rotating body, which the outer surface of the timing belt comes into contact with when the vibration of the timing belt is generated, is arranged at a position on the pulling side of a timing belt used for a valve operating system of an engine. A thrust washer and a ring-shaped elastic body such as rubber are interposed between the head and the head of the fulcrum shaft bolt, and when the timing belt starts to vibrate, the belt comes into contact with the free rotating body to suppress the vibration. However, although this method could realize the measure to prevent the generation of the abnormal noise due to the unnecessary vibration, it had the drawback of increasing the number of parts and increasing the cost.

Therefore, a main object of the present invention is to provide a guide roller for a timing belt which can prevent the generation of impact noise and reduce the number of parts.

[0004]

According to a first aspect of the present invention, there is provided a timing belt guide roller for guiding a timing belt used in a power drive system, wherein the timing belt is provided at a position on the tension side of the timing belt. Is provided with a free rotating body that the outer surface of the timing belt contacts when the vibration occurs, and the contact surface or the whole of the free rotating body is formed of the lubricating rubber composition. The lubricating rubber composition contains a thermoplastic fluororesin which is a first essential component, a fluororubber which is a second essential component, and a low molecular weight fluoropolymer which is a third essential component.

In the present invention, the fluororubber is a polymer or copolymer of unit monomers containing an average of one or more fluorine atoms, has a glass transition point of room temperature or lower, and has rubber-like elasticity at room temperature. There is no particular limitation as long as it has the following, and a wide range can be exemplified.

Examples of the polymerization method of fluororubber include bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization, catalyst polymerization, ionizing radiation polymerization, and redox polymerization. The molecular weight of fluororubber is usually 50,000.
A polymer having a molecular weight of 0 or more is desirable, and a polymer having a molecular weight as high as possible gives good results.
Above all, it is particularly preferable to use one having a size of about 100,000 to 250,000.

Typical examples corresponding to the above conditions are tetrafluoroethylene / propylene copolymer Afras manufactured by Asahi Glass Co., Ltd., vinylidene fluoride / hexafluoropropylene copolymer DuPont / Showa Denko Viton, and fluorine. Fluorovinylidene / hexafluoropropylene / tetrafluoroethylene copolymer Technofluon made by Montefluos, fluorosilicone elastomer Dow Corning Silastic LS, perfluoroelastomer Daikin Industrial Co., Ltd. Can be mentioned.

In the present invention, the thermoplastic fluororesin which is the first essential component has a carbon chain in the main chain,
A polymer having a fluorine bond in its side chain, such as a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (hereinafter abbreviated as PFA) and a tetrafluoroethylene / hexafluoropropylene copolymer (hereinafter referred to as FEP). Abbreviated) and tetrafluoroethylene / ethylene copolymer (hereinafter abbreviated as ETFE). Any of the above resins can be produced by various polymerization methods such as catalyst emulsion polymerization, suspension polymerization, catalyst solution polymerization, gas phase polymerization and ionizing radiation irradiation polymerization. The molecular weight is preferably 50,000 or less, more preferably more than 5,000 and almost 20,000 or less.

As a typical example corresponding to the above conditions, the above-mentioned PFA manufactured by Mitsui DuPont Fluorochemical Co., Ltd. is used.
Examples include MP10 and FEP, Teflon FEP100 manufactured by Mitsui DuPont Fluorochemicals, and ETFE, Aflon COP manufactured by Asahi Glass.

The composition obtained by mixing the above-mentioned fluororubber and thermoplastic fluororesin has characteristics as an elastic body. In the present invention, the low molecular weight fluoropolymer, which is the third essential component, is blended in order to impart even more excellent sliding properties to such an elastic body.

In the present invention, the low molecular weight fluorine-containing polymer means tetrafluoroethylene (TFE), a fluoropolyether having a main structural unit —C _n F _2n —O— (n is an integer of 1 to 4), Structural unit

[0012]

[Chemical 1]

Among the polyfluoroalkyl group-containing compounds (having 2 to 20 carbon atoms) having, for example, those having a molecular weight of 50,000 or less. In order to give excellent sliding properties,
It is particularly desirable that the low molecular weight fluoropolymer has a molecular weight of 5,000 or less. Among such low molecular weight fluorinated polymers, those having an average particle size of 5 μm or less of the tetrafluoroethylene polymer represented by the following formula are particularly preferable.

[0014]

[Chemical 2]

Examples of such materials include Bydax AR manufactured by DuPont and Furuon Lubricant L169 manufactured by Asahi Glass Co., Ltd.

[0016] Next, as -C _n F _2n -O _(n is an integer from 1 to 4) average molecular weight of 50,000 or less fluoropolyethers having a main structural unit of,

[0017]

[Chemical 3]

The following can be exemplified. Such polymers are those having a structural unit containing a functional group such as an isocyanate group, a hydroxyl group, a carboxyl group, and an ester group in order to improve the affinity (adhesion) with other compounding materials and additives. desirable.

Specific examples of such a fluoropolyether include the following.

[0020]

[Chemical 4]

These fluoropolyethers may be used alone or in combination. Further, a fluoropolyether having activated hydrogen as a functional group and an isocyanate compound having no polyfluoropolyether group may be used in combination. Further, a fluoropolyether having an isocyanate group, diamines not containing various fluoropolyether groups, triamines, or diols not containing various fluoropolyether groups,
A method of using triols together may be adopted.

Particularly, it is desirable to use a combination of fluoropolyethers in which functional groups react with each other to increase the molecular weight. As such, it is likewise desirable to combine, for example, those having units containing isocyanate groups with those having units containing hydroxyl groups.

Examples of the polyfluoroalkyl group-containing compound include compounds having a polyfluoroalkyl group as shown below.

[0024]

[Chemical 5]

The above-mentioned polyfluoroalkyl group (having 2 to 20 carbon atoms) having an average molecular weight of 50,000 or less is

[0026]

[Chemical 6]

And the like, a polymer of a reaction product of a compound having a reactive group and a polyfluoroalkyl group with an ethylenically unsaturated compound having a group which reacts with the reactive group (for example, fluoroalkyl acrylate), and Examples thereof include a reaction product of a compound having a reactive group and a polyfluoroalkyl group with various polymers having a group that reacts with the reactive group, or a polycondensation product of the above compound.

Like the above-mentioned fluoropolyether, the polyfluoroalkyl group-containing compound is a functional group having a high affinity for improving the affinity (adhesion) with other compounding materials and additives, such as an isocyanate group, A compound having a unit containing a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an amino group, a sulfone group and the like is preferable.

These polyfluoroalkyl group-containing compounds may be used alone or in combination. In addition, a polyfluoroalkyl group-containing compound having a reactive group having activated hydrogen and an isocyanate compound not having a polyfluoroalkyl group may be used in combination. Also,
Adopting a method such as combining a polyfluoroalkyl group-containing compound having an isocyanate group with various polyfluoroalkyl group-free diamines, triamines or various polyfluoroalkyl group-free diol groups and triols. May be.

The combination of functional groups is preferable from the viewpoint of increasing the strength, and specifically has a polyfluoroalkyl group having 2 to 20 carbon atoms and is selected from a hydroxyl group, a mercapto group, a carboxyl group and an amino group. A combination with a fluoropolymer containing at least one kind, or a fluoropolymer having a polyfluoroalkyl group having 2 to 20 carbon atoms and having a unit containing an isocyanate group, and polyfluoroalkyl having 2 to 20 carbon atoms Examples thereof include a combination with a fluorine-containing polymer having a group and a unit containing a reactive group having activated hydrogen.

Among these low molecular weight fluoropolymers,
It has been found that the use of fluoroolefin polymers or fluoropolyethers gives excellent results in lubricity, and the use of tetrafluoroethylene polymers having an average particle size of 5 μm or less gives the most desirable results.

In the present invention, the mixing ratio of the fluororubber, the thermoplastic fluororesin and the low molecular weight fluoropolymer is such that the weight ratio of the fluororubber to the thermoplastic fluororesin is 5.
It is desirable that the ratio be 0:50 to 95: 5. If the blending weight ratio of the thermoplastic fluororesin exceeds 50/100,
The desired composition does not have sufficient elastic properties, and the ratio is 5/100.
This is because if it is less than this, sufficient abrasion resistance cannot be obtained.

The low molecular weight fluoropolymer is preferably 5 to 50 parts by weight based on 100 parts by weight of the fluororubber and the thermoplastic fluororesin in total. This is because if the compounding ratio of the low molecular weight fluoropolymer is less than 5 parts by weight, sufficient sliding properties cannot be obtained, and if it exceeds 50 parts by weight, the rubber-like elastic properties are impaired.

In addition, with respect to the above-mentioned lubricating rubber composition, 3
Abrasion resistance can be improved by adding a cured powder of a thermosetting resin that does not melt at 00 ° C. or a heat-resistant resin powder having a glass transition point of 300 ° C. or higher.

The thermosetting resin powder is a fine powder of a phenol resin, an epoxy resin or the like after thermosetting, and the heat-resistant resin having a glass transition temperature of 300 ° C. or higher is a polyimide resin or an aromatic aramid resin. A powder is mentioned.

Among the commercially available resin powders, the hardened and ground product of the phenol resin is manufactured by Kanebo Ltd .: Bell Pearl H30.
0, as a cured pulverized product of polyimide resin: PWA20 manufactured by Mikasa Sangyo Co., Ltd .; as a pulverized product of aromatic aramid resin: MP-P manufactured by Asahi Kasei Co., as a thermosetting resin powder having a glass transition point Tg of 300 ° C. or higher. Manufactured by Ube Industries, Ltd .: Upilex S (Tg> 500).

The particle size of such thermosetting resin powder is 1
A resin having a particle size of ˜15 μm is preferable from the viewpoint of maintaining rubber elasticity and easiness of kneading process. The thermosetting resin powder is preferably added in an amount of 5 to 20% by weight with respect to the first to third essential components. If it is less than 5% by weight, the effect of improving wear resistance is not obtained and 2
A large amount exceeding 0% by weight is not preferable because the rubber elasticity decreases.

In addition to the above components, various additives may be added within the range not impairing the object of the present invention. For example, as a vulcanizing agent for fluororubber, isocyanurate, organic peroxide, etc., antioxidants such as sodium stearate, magnesium oxide, and calcium hydroxide, or acid acceptors, antistatic agents such as carbon, silica, alumina, etc. It goes without saying that the above-mentioned fillers, other metal oxides, colorants, flame retardants and the like may be appropriately added.

The method of mixing the various raw materials described above is not particularly limited, and the generally-used methods can be used for mixing. For example, the elastomer as the main raw material and the other raw materials may be individually mixed sequentially or simultaneously by a roll mixer or other mixer. At this time, it is desirable to provide a temperature controller to prevent heat generation due to friction.

When a roll mixer is used,
For finishing mixing, it is more preferable to tighten the roll interval to about 3 mm or less and perform thin threading.

The thrust washer material according to the present invention does not require any specially limited means in the molding process, and the primary vulcanization (140-17
After performing a pressure of 5 to 10 kgf / cm ² for 10 to 30 minutes at 0 ° C., secondary vulcanization (for example, 2 to 2 at 200 to 300 ° C.)
It may be molded into a seal by applying no pressure for 0 hours.

Further, only the lip-shaped portion or the portion of the lip-shaped portion which is the seal portion of the thrust washer material and which is in contact with the shaft is molded with the lubricating component composition containing the above-mentioned first to third essential components, Other parts may be composite-molded with general synthetic rubber, plastic or metal.

As the general synthetic rubber at this time, vulcanized rubber such as nitrile rubber, chloroprene rubber, butadiene rubber, urethane rubber, styrene rubber, butyl rubber, acrylic rubber, silicone rubber, ethylene rubber, and fluorine rubber, or urethane, polyester. , Thermoplastic elastomers such as polyamide, vinyl chloride, polybutadiene, and soft nylon, and liquid elastomers such as liquid urethane and liquid butadiene.

[0044]

In the timing belt guide roller according to the present invention, the contact surface or the whole of the free rotating body is the thermoplastic fluororesin as the first essential component, the fluororubber as the second essential component and the low content as the third essential component. When the belt is subjected to string vibration, it is possible to suppress the vibration of the belt by coming into contact with the free rotation body when the belt is vibrated. At this time, the free rotating body rotates, the frictional resistance between the belt and the rotating body is reduced, and wear can be prevented. At the same time, when the belt is vibrated such as twisting, the belt is subjected to an axial impact load on the free rotating body, but the impact force is absorbed by forming the free rotating body with the lubricating rubber composition. Prevent the generation of impact noise.

[0045]

1 is a sectional view of an embodiment of the present invention.
Referring to FIG. 1, one end of mounting material 2 is fixed on engine 1 by tightening bolt 3, and fulcrum shaft bolt 4 is mounted on the other end of mounting material 2. A free rotating body 5 is provided on the fulcrum shaft bolt 4 so as to be rotatable with respect to the fulcrum shaft bolt 4. The free rotating body 5 is formed of a lubricating rubber composition.

FIG. 2 is a sectional view showing another embodiment of the present invention. In the embodiment shown in FIG. 2, the thrust washer 7 is caulked to the root of the fulcrum shaft bolt 4 which is screwed and fixed to the engine 1, and the head 8 of the bolt 6 and the thrust washer 7 are fixed.
A free rotating body 9 is rotatably provided between and. The free rotating body 9 is also made of a lubricious rubber composition.

The raw materials used in Examples and Comparative Examples are collectively shown below. The mixing ratios of the respective components are all% by weight, but for the raw materials shown in (3) to (9), the total weight of the raw materials shown in (1) and (2) is 10
% By weight with respect to 0.

(1) Vinylidene fluoride / fluoropropylene copolymer (Technoflon FOR4 manufactured by Asahi Monte Corporation)
20) (2) Tetrafluoroethylene / ethylene copolymer
(Aflon COP manufactured by Asahi Glass Co., Ltd.) (3) Low molecular weight fluoropolymer (low molecular weight TFE)
(Lubricant L169 manufactured by Asahi Glass Co., Ltd.) (4) Low molecular weight fluoropolymer (low molecular weight PFPE)
(Japan Anymont Fomblin Z-DISO
C) (5) Carbon (MT carbon manufactured by Fadelbilt) (6) Sodium stearate (general industrial material) (7) Magnesium oxide (general reagent) (8) Calcium hydroxide (general reagent) (9) Phenolic resin (Kanebo) Belpearl H300) (10) Nitrile-butadiene copolymer (NBR)
(General industrial materials hardness JIS-A70) (11) Dimethyl silicone polymer (silicon rubber)
(General industrial material hardness JIS-A70) (12) Polyimide molding (Vespel SP21 manufactured by DuPont) First, the fluororubber (1) is wound around a roll mixer having a roll interval of about 5 to 10 mm, and shown in Table 1. MT carbon, sodium stearate, Mg
O and Ca (OH) ₂ were added and kneaded. Then, the roll interval was adjusted to 1 mm, and mastication was performed about 10 times. For the purpose of preventing frictional heat at this time, cooling water was constantly passed through the roll to keep the roll temperature at 60 ° C or lower. Next, cooling water is stopped, steam is passed through the rolls, the rubber temperature is adjusted to 70 ° C or higher and 90 ° C or lower, and then the roll interval is returned to about 5 to 10 mm to obtain a low molecular weight fluoropolymer. Was added little by little and kneaded at the compounding ratio of each example shown in Table 1. After that, set the roll interval to 1 again.
It narrowed to mm and masticated 10 times.

[0049]

[Table 1]

In the compound obtained in the above steps, 150 × 150 × 1t sheet was subjected to primary vulcanization (170
It was manufactured by carrying out secondary vulcanization (230 ° C., 16 hours, free) at 10 ° C. for 10 minutes at a pressing pressure of 7 kgf / cm ² .
For each test piece, a friction test, an abrasion test, a non-stick property and an elastic body property were obtained. The method of each test is as follows.

(1) Test method-friction and wear test The obtained test piece was processed into an inner diameter of φ17 and an outer diameter of φ21, and φ
A ring test piece was obtained by adhering it to a 17 × φ21 × 10 SPCC ring piece. Mating material is SUJ2 (bearing steel) φ6 × φ
A 33 × 6 disc-shaped test piece was prepared and evaluated using a thrust type friction wear tester. The condition is a sliding speed of 128 m / min,
The surface pressure was 3.5 kgf / cm ² . Table 2 shows the friction coefficient and wear coefficient after 500 hours.

(2) Non-adhesion In the obtained test piece, the contact angle to water was measured by a goniometer-type contact angle measuring device, and it was judged that the larger the contact angle, the better the non-adhesiveness. The results are shown in Table 2.

(3) Elastic Body Properties The obtained test piece is compliant with JIS-K6301,
The tensile strength, elongation, and hardness (JIS-A) were investigated. The results are shown in Table 2.

(4) Impact resistance properties The test pieces obtained were tested according to ASTM D256,
The Izod impact strength was investigated. The results are shown in Table 2.

[0055]

[Table 2]

Comparative Example In the comparative example, the raw materials were blended in the proportions shown in Table 1, and kneading, molding and vulcanization were performed in the same manner as in the examples. In addition, the test pieces were adjusted and tested in exactly the same manner as in the examples. The results are shown in Table 2.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols] 1 engine 2 mounting material 3 bolts 4,6 fulcrum shaft bolts 5,9 free rotating body 7 thrust washer 8 head

Claims (7)

[Claims] 1. A timing guide roller for guiding a timing belt used in a power drive system, wherein an outer surface of the timing belt is located at a position on the tension side of the timing belt when vibration of the timing belt occurs. A free rotating body that comes into contact, the contact surface or the whole of the free rotating body is formed of a lubricating rubber composition, and the lubricating rubber composition is a thermoplastic fluororesin which is a first essential component, and a second essential component And a low molecular weight fluoropolymer which is the third essential component,
Guide roller for timing belt. 2. The guide roller for a timing belt according to claim 1, wherein a cured powder of a thermosetting resin or a heat resistant resin powder having a glass transition point of 300 ° C. or higher is added to the lubricating rubber composition. 3. The thermoplastic fluororesin as the first essential component is a tetrafluoroethylene / ethylene copolymer,
The guide roller for a timing belt according to claim 1, which is one or more selected from the group consisting of a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer and a tetrafluoroethylene / hexafluoropropylene copolymer. 4. The second essential component has a molecular weight of 100,0.
A fluororubber of from 00 to 250,000.
Guide roller for timing belt. 5. The fluororubber which is the second essential component,
Group consisting of tetrafluoroethylene / propylene copolymer, vinylidene fluoride / hexafluoropropylene copolymer, vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene copolymer, fluorosilicone copolymer and perfluoro-based copolymer The timing belt guide roller according to claim 1, which is one or more polymers selected from the group consisting of: 6. The low molecular weight fluoropolymer as the third essential component is selected from the group consisting of tetrafluoroethylene polymers having an average molecular weight of 50,000 or less, fluoropolyethers and polyfluoroalkyl group-containing compounds.
The guide roller for a timing belt according to claim 1, which is one or more polymers. 7. The guide roller for a timing belt according to claim 1, wherein the low molecular weight fluoropolymer which is the third essential component is a tetrafluoroethylene polymer having an average particle size of 5 μm or less.