JP2007247752A - Rolling bearing, rolling bearing for tenter clip, tenter clip, and film drawing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing suitable for a tenter clip in particular with a longer lifetime, and process a tenter clip and a film drawing machine in long lifetime. <P>SOLUTION: The film drawing machine comprises the tenter clip comprising the rolling bearing for the above-mentioned tenter clip. The rolling bearing for the tenter clip which consists of the rolling bearing which comprises a plurality of rolling elements arranged to be freely rolled between an inner ring and an outer ring, and is filled with a grease compound containing a base oil containing a specific branch alkyl side-chain diphenyl ether oil, and a thickener. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rolling bearing. The present invention also relates to a rolling bearing for a tenter clip, a tenter clip and a film stretching machine to which the rolling bearing is applied.

  Conventionally, fluorine grease made of fluorine oil and polytetrafluoroethylene resin (PTFE) powder has been widely used for rolling bearings for tenter clips. As such a grease, for example, a Varielta series manufactured by NOK Crububa Co., Ltd. is known.

  In a film stretching machine, a film is stretched by attaching the film to a tenter clip, placing it in a high-temperature (for example, about 220 ° C.) tenter oven, and running the tenter clip along a guide rail. Since the tenter clip is thus exposed to high temperatures, only fluorine grease can be used as the grease filled in the rolling bearing for the tenter clip.

  When the tenter clip travels, the tenter clip rolling bearing provided on the tenter clip rolls on the guide rail (rotating the outer ring). The outer ring of the tenter clip rolling bearing and the guide rail The contact portion was lubricated by spraying ester oil. A rolling bearing used as a tenter clip rolling bearing is often a small-diameter ball bearing having an inner diameter of 17 mm and an outer diameter of about 40 mm, and often has a metal shield.

  As for conventional rolling bearings for tenter clips, for example, the following patent documents can be referred to.

JP-A-6-344437 Japanese Utility Model Publication No. 62-183131 JP 2000-289773 A Japanese Patent Publication No.7-113374 JP 11-294461 A JP 2000-273478 A JP 2000-230184 A JP-A-11-199886

  However, since ester oil has an ester group, it has a stronger affinity for metals compared to fluorine oil. Therefore, if ester oil enters the rolling bearing for tenter clips, the adhesion of fluorine grease to the metal decreases. As a result, the fluorine grease may leak out of the bearing. Therefore, the problem that the life of the rolling bearing for a tenter clip is reduced may occur.

  In particular, when the rolling bearing for the tenter clip is disposed below the guide rail, the ester oil falling along the guide rail easily enters the inside of the rolling bearing for the tenter clip. Therefore, the rolling bearing for the tenter clip tends to have a shorter life. This leakage of fluorine grease is not caused by the centrifugal force generated by the rotation of the bearing, but is considered to be caused by vibration caused by the outer ring coming into contact with the guide rail.

  If fluorine oil is used instead of ester oil, even if it enters the rolling bearing for the tenter clip and is mixed with fluorine grease, the above-mentioned problems will hardly occur to the extent that the fluorine grease softens. Seem. However, since fluorine oil is expensive and cannot be discarded as it is, it is desirable that the amount used is small.

  Fluorine grease is expected to leak from the labyrinth between the seal device attached to the bearing and the outer peripheral surface of the inner ring. If a contact-type seal device is used for the rolling bearing for the tenter clip, grease leakage will occur. It can be suppressed. However, the contact-type sealing device cannot often be used due to a torque problem. That is, hundreds to thousands of tenter clips are used for a normal film stretching machine, and therefore, there are cases where the number of rolling bearings for tenter clips that are normally provided for each tenter clip is tens of thousands. is there. This is because when a contact-type sealing device is used for a large number of tenter clip rolling bearings, the torque generated when the tenter clip travels may increase.

  Accordingly, an object of the present invention is to solve the above-described problems of the prior art and to provide a rolling bearing that has a longer life and is particularly suitable for a tenter clip. Moreover, it aims at extending the lifetime of a tenter clip and a film stretching machine.

In order to solve the above problems, the present invention provides the following rolling bearing, rolling bearing for tenter clip, tenter clip, and film stretching machine.
(1) a base oil containing a branched alkyl side chain diphenyl ether oil represented by the general formula (I), and a plurality of rolling elements that are rotatably arranged between the inner ring and the outer ring; A rolling bearing filled with a grease composition containing an agent.

[Wherein, one of R1, R2 and R3 is a hydrogen atom, and the remaining two are branched alkyl groups having 10 to 26 carbon atoms, which may be the same or different. ]
(2) The base oil contains the branched alkyl side chain diphenyl ether oil represented by the general formula (I) at a ratio of 50 to 100% by mass, and the kinematic viscosity at 40 ° C. is 20 to 500 mm ² / s. The rolling bearing according to (1) above, characterized in that
(3) The rolling bearing according to the above (1) or (2), wherein the grease composition has a penetration of 220 to 385.
(4) A tenter clip rolling bearing provided on a tenter clip that travels along a guide rail of a film stretching machine while holding a film, and that rolls on the guide rail, the above (1) to (3) A rolling bearing for a tenter clip, comprising the rolling bearing according to any one of the above.
(5) In a tenter clip including a holding unit for holding a film and a rolling bearing that rolls on a guide rail of a film stretching machine, the rolling bearing is the rolling bearing for a tenter clip described in (4) above. Features a tenter clip.
(6) A film stretching machine comprising a tenter clip for holding a film and a guide rail for guiding the travel of the tenter clip, wherein the tenter clip is the tenter clip according to (5) above. Machine.

  Since the base oil of the grease composition to be filled contains a specific alkyl side chain diphenyl ether oil, the rolling bearing of the present invention has a higher lubricating performance. Therefore, the tenter clip rolling bearing of the present invention comprising the rolling bearing, the tenter clip of the present invention further including the tenter clip rolling bearing, and the film stretching machine of the present invention also have a long life.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  The structure of the rolling bearing of the present invention is not limited, and for example, a ball bearing shown in FIG. 1 can be exemplified. The ball bearing shown in the figure holds an inner ring 1, an outer ring 2, a plurality of balls 3 that are rotatably arranged between both wheels 1 and 2, and a plurality of balls 3 between both wheels 1 and 2. A cage 4 and non-contact type rubber seals 5 and 5 are provided. A gap 6 surrounded by the inner ring 1, the outer ring 2, and the rubber seals 5 and 5 is filled with a grease composition G shown below and sealed inside the bearing by the rubber seal 5. The grease composition G lubricates the contact surfaces between the raceways 1a and 2a of the wheels 1 and 2 and the balls 3. The rubber seal 5 has an annular shape, and the outer peripheral edge of the rubber seal 5 is inserted into seal grooves 2b, 2b having a substantially V-shaped cross section provided at both ends of the inner peripheral surface of the outer ring 2 over the entire circumference of the outer ring 2. It is fixed. The inner peripheral edge of the rubber seal 5 is close to the outer peripheral surface of the inner ring 1 (non-contacting), and the rubber seals 5 and 5 almost cover the opening between the outer peripheral surface of the inner ring 1 and the inner peripheral surface of the outer ring 2. ing. As a result, the grease composition G and the generated dust existing in the gap 6 (where the balls 3 are installed) formed between the inner ring 1 and the outer ring 2 leak to the outside or float to the outside. Dust is prevented from entering the gap 6.

  In the grease composition, the base oil contains a branched alkyl side chain diphenyl ether oil represented by the general formula (I) as an essential component.

  In the formula (I), one of R1, R2 and R3 is a hydrogen atom, and the other two are branched alkyl groups, which may be the same or different. Moreover, in a branched alkyl group, carbon number is 10-26, Preferably it is 12-24. A branched alkyl group having more than 26 carbon atoms has a high pour point and poor fluidity at low temperatures, which causes a problem in use. When the branched alkyl group has less than 10 carbon atoms, the amount of evaporation increases, which causes a problem in use. Of the branched alkyl groups, a branched decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group and the like are preferable.

  Moreover, it is preferable that branched alkyl side chain diphenyl ether oil is 50-100 mass% of the base oil whole quantity. As the lubricating oil that can be mixed, a linear alkyl side chain diphenyl ether oil represented by the following general formula (II) is preferable.

  In the formula (II), one of R 4, R 5 and R 6 is a hydrogen atom, and the other two are straight chain alkyl groups, preferably 8 to 20 carbon atoms, more preferably a straight chain having 12 to 14 carbon atoms. A chain alkyl group. In the case of a linear alkyl group having more than 20 carbon atoms, the pour point is increased and the fluidity at low temperature is poor, which causes a problem in use. In the case of a linear alkyl group having less than 8 carbon atoms, the amount of evaporation becomes large, which causes a problem in use.

  In addition to the above-mentioned linear alkyl side chain diphenyl ether oil, an ester synthetic oil and a polyalphaolefin oil may be mixed with the base oil. Examples of ester synthetic oils include diesters such as di-2-ethylhexyl sebacate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, polyol esters such as trimethylolpropane caprylate, pentaerythritol-2-ethylhexanoate, and trioctyl. Examples include trimellitic acid esters such as trimellitate and tridecyl trimellitate, and aromatic ester oils of pyromellitic acid esters such as tetraoctyl pyromellitate. The polyalphaolefin oil is preferably represented by the following general formula (III).

  R7 in the formula (III) is an alkyl group, and different alkyl groups may be mixed in the same molecule, but is preferably an n-octyl group. N is preferably an integer of 3 to 8.

The base oil preferably has a kinematic viscosity at 40 ° C. of ²⁰ to 500 mm ² / s. If the kinematic viscosity at 40 ° C. exceeds 500 mm ² / s, the torque will increase too much, and the fluidity at low temperatures will be insufficient, which may cause abnormal noise when starting at low temperatures. Further, if the kinematic viscosity at 40 ° C. is less than 20 mm ² / s, there is a concern about evaporation loss and lubricity problems. For example, sufficient lubrication to avoid metal contact between the raceway surface and the rolling element during rotation of the bearing at high temperature. Oil film formation may be difficult. From such a point, the kinematic viscosity at 40 ° C. of the base oil is more preferably 30 to 400 mm ² / s.

  The thickener can be used without limitation as long as it is a substance that is colloidally dispersed in the above base oil to make the base oil semi-solid or solid. Examples of such a thickener include lithium soap, calcium soap, sodium soap, aluminum soap, lithium complex soap, calcium complex soap, sodium complex soap, barium complex soap, and aluminum complex soap. And metal based soaps, bentonite, clay based inorganic compounds, monourea based, diurea based, triurea based, tetraurea based, urethane based, sodium terephthalate based organic compounds, and the like. Among these, a urea system can be preferably used. These thickeners may be used alone or in combination of two or more.

  The content of the thickener is 3 to 40% by mass of the total amount of grease, and preferably 5 to 25% by mass is dispersed in the base oil. If the amount is less than 3% by mass, it is difficult to maintain the grease state, and if it exceeds 40% by mass, the grease composition becomes too hard to exhibit a sufficient lubrication state.

  The penetration is preferably in the range of 220 to 385, more preferably in the range of 265 to 350 in terms of penetration. If the penetration is less than 220, the grease composition becomes too hard and a sufficient lubricating effect cannot be expected. If it is greater than 385, the grease composition is too soft and may leak from the bearing.

  In order to further improve the various performances, the grease composition may be mixed with various additives as desired. For example, antioxidants such as amines such as phenyl-1-naphthylamine, phenols such as 2,6-di-tert-dibutylphenol, sulfurs and zinc dithiophosphate; organic sulfones such as alkali metals and alkaline earth metals Rust preventive agents such as acid, alkyl, alkenyl succinic acid esters such as alkyls, alkenyl succinic acid derivatives, partial esters of polyhydric alcohols such as sorbitan monooleate; extreme pressure agents such as phosphorus, zinc dithiophosphate and organic molybdenum Oiliness improvers such as fatty acids and animal and vegetable oils; metal deactivators such as benzotriazole and the like can be added alone or in admixture of two or more. In addition, the addition amount of these additives will not be specifically limited if it is a grade which does not impair the objective of this invention.

  In addition, the manufacturing method of a grease composition is not specifically limited.

  As the rolling bearing, in addition to the ball bearing, for example, a radial rolling bearing such as an angular ball bearing, a self-aligning ball bearing, a cylindrical roller bearing, a tapered roller bearing, a needle roller bearing, or a self-aligning roller bearing. Thrust-type rolling bearings such as bearings, thrust ball bearings, thrust roller bearings and the like can be mentioned, and the above grease composition is similarly encapsulated.

  As described above, the rolling bearing of the present invention filled with the grease composition containing the branched alkyl side chain diphenyl ether oil in the base oil has excellent lubricity and has a long life even at high temperatures. Therefore, the rolling bearing of the present invention is suitable as a bearing for a tenter clip. Hereinafter, an embodiment applied to a tenter clip will be described.

  A tenter clip 10 shown in FIG. 2 includes a holding portion 11 that holds a film 18, a plurality of rolling bearings 12, and a tenter clip main body 15 to which the holding portion 11 and the rolling bearing 12 are attached. Each of the rolling bearings 12 attached to the inner ring 12a has an inner ring 12a as a fixed ring and an outer ring 12b as a rotating ring. The tenter clip 10 mounted on the guide rail 19 so that the outer peripheral surface of the outer ring 12b of each rolling bearing 12 contacts the guide rail 19 of a film stretching machine (not shown) causes the rolling bearings 12 to roll. Via the guide rail 19. In order to lubricate the contact portion between the outer peripheral surface of the outer ring 12b and the guide rail 19, lubricating oil such as ester oil is sprayed on the contact portion during traveling.

  In the present invention, a rolling bearing formed by filling the grease composition containing the above branched alkyl side chain diphenyl ether oil in the base oil is used as the rolling bearing 12. Specifically, having a structure shown in FIG. 1, 80% by mass of a base oil composed of 70% by mass of branched alkyl side chain diphenyl ether oil and 40% by mass of poly-α-olefin oil, and a diurea compound An example is a ball bearing (nominal number 6203, an inner diameter of 17 mm, an outer diameter of 40 mm, and a width of 15 mm) filled with a grease composition composed of 20% by mass of a thickener. By using such a rolling bearing, even when lubricating oil such as ester oil is sprayed on the contact portion during traveling, good lubricity can be maintained for a long time.

  Further, the film stretching machine of the present invention includes a large number of such tenter clips 10. And after attaching using the holding | maintenance part 11 to the both right and left sides of the film 18, it is made to drive | work along the two guide rails 19 arrange | positioned in substantially C shape, heating at high temperature (for example, 220 degreeC). As a result, the tenter clips 10 on both the left and right sides of the film 18 are gradually widened as they travel, and the film 18 is stretched because tension in the left-right direction is applied to the film 18. The heating temperature described above may be set according to the material of the film 18 and the degree of stretching. Such a film stretching machine can also maintain good lubricity for a long time.

It is a fragmentary longitudinal cross-section which shows one Embodiment of the rolling bearing which concerns on this invention, and the rolling bearing for tenter clips. It is a side view showing one embodiment of the tenter clip concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Ball 5 Rubber seal 6 Gap part G Grease composition 10 Tenter clip 11 Holding part 12 Rolling bearing 12a Inner ring 12b Outer ring 18 Film 19 Guide rail

Claims (6)

A base oil containing a branched alkyl side chain diphenyl ether oil represented by the general formula (I), a thickener, and a plurality of rolling elements disposed between the inner ring and the outer ring so as to freely roll. A rolling bearing characterized by being filled with a grease composition.

[Wherein, one of R1, R2 and R3 is a hydrogen atom, and the remaining two are branched alkyl groups having 10 to 26 carbon atoms, which may be the same or different. ] The base oil contains a branched alkyl side chain diphenyl ether oil represented by the general formula (I) at a ratio of 50 to 100% by mass, and has a kinematic viscosity at 40 ° C. of ²⁰ to 500 mm ² / s. The rolling bearing according to claim 1.   The rolling bearing according to claim 1 or 2, wherein the grease composition has a penetration of 220 to 385.   A tenter clip rolling bearing provided on a tenter clip that travels along a guide rail of a film stretching machine while holding a film, and that rolls on the guide rail. A rolling bearing for a tenter clip, comprising the rolling bearing described.   A tenter clip comprising a holding unit for holding a film and a rolling bearing that rolls on a guide rail of a film stretching machine, wherein the rolling bearing is a rolling bearing for a tenter clip according to claim 4. clip. 6. A film stretching machine comprising: a tenter clip that holds a film; and a guide rail that guides the travel of the tenter clip, wherein the tenter clip is the tenter clip according to claim 5.

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