JP2010000708A - Guide roller bearing for tenter clip of film stretcher - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a guide roller bearing for a tenter clip of a film stretcher which can improve wear resistance and corrosion resistance while inhibiting the deterioration of a life resulting from a high Young's modulus. <P>SOLUTION: The guide roller bearing 1 is arranged in contact with a guide rail between the tenter clip of the film stretcher and a guide rail disposed opposite to the tenter clip, and guides the tenter clip along the guide rail. The constituent ball 13 of the guide roller bearing is constituted of a sintered body composed mainly of β sialon which can satisfy 0.1≤z≤3.5 as represented by composition formula of Si<SB>6-Z</SB>Al<SB>Z</SB>O<SB>Z</SB>N<SB>8-Z</SB>and the rest of impurities. Furthermore, the Young's modulus of the ball is not smaller than 180 GPa to not larger than 270 GPa. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a guide roller bearing for a film stretching machine tenter clip, and more particularly to a guide roller bearing for a film stretching machine tenter clip provided with a component composed of a sintered body mainly composed of β sialon. is there.

  A film stretcher is a sheet of resin raw material extruded by a melt extruder, and is continuously sandwiched between tenter clips, and the sheet of resin raw material is pulled with a tenter clip. Stretch by applying stress. A guide roller serving as a wheel is fixed to the tenter clip. When the guide roller circulates on the guide rail, the tenter clip moves on the guide rail along the guide rail. Here, by arranging the guide rails so that the resin material formed into a sheet shape can be stretched, the tenter clip can form the resin material into a film shape having a desired size.

  In the above-described step of stretching the resin raw material, the tenter clip is exposed to a high temperature atmosphere of 150 to 250 ° C., so that the rolling bearing used for the guide roller of the tenter clip is required to have heat resistance. Therefore, fluorine rubber or silicone rubber is employed as a seal used to prevent leakage of the lubricant to be sealed in order to increase the lubricity of the rolling bearing and prevent foreign matter from entering the inside of the rolling bearing. In addition, grease with excellent heat resistance is also applied to the grease sealed in the rolling bearing, and in general, fluorine grease is often employed.

However, when a rolling bearing is used in a high-temperature atmosphere such as a tenter clip of a film stretching machine, the viscosity of the grease enclosed inside the rolling bearing is reduced even if grease having excellent heat resistance is used. . As a result, the grease sealed inside the rolling bearing is likely to leak. If the grease leaks, the amount of grease inside the rolling bearing decreases, so that there is a high possibility of causing damage to the rolling bearing. Therefore, Patent Document 1 discloses a method for suppressing the leakage of grease during use of a rolling bearing by devising a region where grease is initially charged.
JP 2007-321882 A

  Although the invention according to Patent Document 1 can suppress a decrease in the amount of grease inside the rolling bearing, there remains a problem with respect to the quality of the grease inside the rolling bearing. As will be described later, when a resin raw material formed into a sheet shape using a film stretching machine is stretched, a step of subjecting the raw material to immersion in water and subjecting it to a humidity conditioning treatment is performed before the raw material is put into the film stretching machine. Do. After the humidity conditioning treatment, a treatment for removing water droplets on the surface of the raw material is performed. Even when the treatment is performed, when the raw material is sandwiched between tenter clips of the film stretching machine, water droplets remaining on the surface of the raw material are dripped. Sometimes. Then, water droplets may be mixed in the grease inside the rolling bearing of the film stretching machine, and the quality of the grease as a lubricant may deteriorate. As a result, there is a possibility of affecting the wear resistance and corrosion resistance of the ball as a rolling element used in the rolling bearing.

  By the way, although the specific description about the kind of ball | bowl as a rolling element used for a rolling bearing is not made | formed in patent document 1, it is nitrided as a rolling element of the rolling bearing used in the environment where corrosion resistance is a problem. Silicon rolling elements may be employed. Since silicon nitride is superior in wear resistance and corrosion resistance as compared with steel generally used as a rolling element material, in recent years, silicon nitride is increasingly used to improve reliability. By using silicon nitride, it is possible to eliminate the problem of deterioration of the wear resistance and corrosion resistance of the rolling elements accompanying the deterioration of the quality of the grease as the lubricant.

  However, silicon nitride has a characteristic that it has a Young's modulus larger than that of steel and is less likely to be elastically deformed. For this reason, the contact area between the rolling element made of silicon nitride and the raceway member is smaller than the rolling element made of steel, and the contact surface pressure tends to increase. Therefore, when a rolling element made of silicon nitride is employed as the rolling element of the rolling bearing, for example, when an impact is applied to the rolling bearing when driving the film stretching machine, it becomes easy to promote wear and damage to the race member. Therefore, as a result, there is a problem that the life of the raceway member may be reduced due to the promotion of damage.

  Accordingly, an object of the present invention is to provide a guide roller bearing for a film stretching machine tenter clip capable of improving wear resistance and corrosion resistance while suppressing a decrease in life due to a high Young's modulus.

  A guide roller bearing for a film stretching machine tenter clip according to the present invention is disposed in contact with a guide rail between a tenter clip of a film stretching machine and a guide rail disposed opposite to the tenter clip. Is a guide roller bearing for a film stretching machine tenter clip. The guide roller bearing includes a raceway member that is disposed in contact with the guide rail and has an annular shape, and a rolling element that is in contact with the raceway member and disposed on the annular raceway. And the rolling element consists of ceramics which can suppress the impact with respect to a track member compared with the case where it consists of silicon nitride. More specifically, for example, the rolling element is made of ceramics having a Young's modulus smaller than that of silicon nitride.

  According to the guide roller bearing for the film stretching machine tenter clip of the present invention, wear and damage in the raceway member are suppressed even when an impact is applied, so that the wear resistance and the corrosion resistance are improved while improving the impact resistance. Guide roller bearings can be provided.

  A guide roller bearing for a film stretching machine tenter clip according to one aspect of the present invention is disposed in contact with the guide rail between a tenter clip of the film stretching machine and a guide rail disposed to face the tenter clip. A film roller tenter clip guide roller bearing for guiding the tenter clip along the guide rail. Specifically, the track member is disposed in contact with the guide rail and has an annular shape, and a rolling element in contact with the track member and disposed on the annular track. This is a guide roller bearing for a tenter clip for a film stretching machine, which is composed of a sintered body containing sialon as a main component and the remaining impurities.

  A guide roller bearing for a film stretching machine tenter clip according to another aspect of the present invention is disposed in contact with the guide rail between a tenter clip of the film stretching machine and a guide rail disposed to face the tenter clip. A film roller tenter clip guide roller bearing for guiding the tenter clip along the guide rail. Specifically, the track member is disposed in contact with the guide rail and has an annular shape, and a rolling element in contact with the track member and disposed on the annular track. This is a guide roller bearing for a film stretching machine tenter clip, which is composed of a sintered body containing sialon as a main component and the remaining sintering aid and impurities.

In the guide roller bearing for a film stretching machine tenter clip in one aspect of the present invention, a β sialon sintered body (sintered body containing β sialon as a main component) that is an insulator is employed as a rolling element. The β sialon sintered body has a lower Young's modulus than a sintered body made of a general ceramic such as silicon nitride (Si ₃ N ₄ ) or alumina (Al ₂ O ₃ ). Therefore, it is possible to suppress a decrease in the life of the track member due to an impact or the like due to an increase in contact surface pressure with the track member due to a high Young's modulus of the rolling element. In addition, by using a sialon sintered body, the effect of improving the wear resistance and corrosion resistance of the rolling element is obtained as in the case of using silicon nitride instead of steel as the rolling element. As described above, according to the guide roller bearing for a film stretching machine tenter clip in one aspect of the present invention, it is possible to improve wear resistance and corrosion resistance while suppressing a decrease in life due to a high Young's modulus. A guide roller bearing for a tenter clip can be provided.

  A guide roller bearing for a film stretching machine tenter clip according to another aspect of the present invention has basically the same configuration as the guide roller bearing for a film stretching machine tenter clip according to one aspect of the present invention. Has the effect of. However, in the guide roller bearing for a film stretching machine tenter clip according to another aspect of the present invention, the guide roller bearing for a film stretching machine tenter clip according to one aspect of the present invention described above in that the sintered body contains a sintering aid. Is different. According to the guide roller bearing for a film stretching machine tenter clip in another aspect of the present invention, the use of a sintering aid makes it easy to lower the porosity of the sintered body and ensures sufficient durability stably. It is possible to easily provide a guide roller bearing for a film stretching machine tenter clip.

  As the sintering aid, at least one of magnesium (Mg), aluminum (Al), silicon (Si), titanium (Ti), rare earth element oxide, nitride, and oxynitride is employed. be able to. In order to achieve the same effect as the guide roller bearing for a film stretching machine tenter clip in one aspect of the present invention, the sintering aid is preferably 20% by mass or less of the sintered body. .

In the guide roller bearing for a film stretching machine tenter clip, the β sialon is preferably expressed by a composition formula of Si _6-Z Al _Z O _Z N _8-Z and satisfies 0.1 ≦ z ≦ 3.5.

  The inventor has investigated in detail the relationship between the rolling fatigue life of a rolling element made of a β sialon sintered body and the composition of β sialon. As a result, the following knowledge was obtained. By adopting a production process including combustion synthesis, β sialon can be produced inexpensively with various compositions having a value of z (hereinafter referred to as z value) of 0.1 or more. In general, the hardness that greatly affects the rolling fatigue life hardly changes in the range of the z value of 4.0 or less that is easy to manufacture. However, when the relationship between the rolling fatigue life of the rolling element made of β sialon sintered body and the z value is investigated in detail, when the z value exceeds 3.5, the rolling fatigue life of the rolling element may decrease. I understood.

  More specifically, when the z value is in the range of 0.1 or more and 3.5 or less, the rolling fatigue life is substantially the same, and if the operation time of the rolling bearing exceeds a predetermined time, the surface of the rolling element is peeled off. Occurs and breaks. On the other hand, if the z value exceeds 3.5, the rolling elements are likely to be worn, resulting in a decrease in the rolling fatigue life. That is, it becomes clear that the failure mode of the rolling element made of β sialon changes with the composition having the z value of 3.5 as a boundary, and the rolling fatigue life decreases when the z value exceeds 3.5. It was. Therefore, in the rolling element made of β sialon sintered body, the z value is preferably set to 3.5 or less in order to ensure a stable and sufficient life. As described above, by providing the β sialon satisfying 0.1 ≦ z ≦ 3.5, it is possible to provide a guide roller bearing for a film stretching machine tenter clip that is inexpensive and excellent in durability. .

In the guide roller bearing for a film stretching machine tenter clip, the β sialon is preferably represented by a composition formula of Si _6-Z Al _Z O _Z N _8-Z and satisfies 0.5 ≦ z ≦ 3.0.

  Thereby, the durability of the guide roller bearing for the film stretching machine tenter clip when a vibration or impact is applied can be further improved.

  In the guide roller bearing for a film stretching machine tenter clip, preferably, the rolling element has a Young's modulus of 180 GPa or more and 270 GPa or less.

  When the Young's modulus of the rolling element increases, the strength of the material (β sialon sintered body) constituting the rolling element tends to increase. However, when the Young's modulus of the rolling elements is increased, the rolling elements are less likely to be elastically deformed, so that the contact area between the rolling elements is reduced and the contact surface pressure is increased. As a result, the counterpart member is likely to be damaged. On the other hand, when the Young's modulus of the rolling elements becomes low, the rolling elements are easily elastically deformed, so that the contact area between the rolling elements increases and the contact surface pressure decreases. However, on the other hand, when the Young's modulus of the rolling element becomes low, the strength of the material constituting the rolling element tends to decrease. Therefore, it is necessary for the Young's modulus of the rolling elements to be in a range that can ensure a balance between the strength of the material constituting the rolling elements and the reduction of the contact surface pressure between the rolling elements.

  More specifically, when the Young's modulus of the rolling element made of β sialon sintered body is less than 180 GPa, the influence of the strength reduction of the material constituting the rolling element exceeds the effect of reducing the contact surface pressure, and the rolling element rolling Dynamic fatigue life is reduced. Further, as the contact area between the rolling elements increases, the frictional force acting between the rolling elements increases to increase the bearing torque, and the temperature of the rolling elements easily rises during use. Therefore, the Young's modulus of the rolling element made of the β sialon sintered body is preferably 180 GPa or more, and more preferably 220 GPa or more.

  On the other hand, when the Young's modulus of the rolling element made of β sialon sintered body exceeds 270 GPa, the effect of increasing the contact surface pressure exceeds the effect of increasing the strength of the material constituting the rolling element, and damages the rolling surface of the mating member. Is likely to occur. As a result, the life of the guide roller bearing for the film stretching machine tenter clip is reduced. Therefore, the Young's modulus of the rolling element made of the β sialon sintered body is preferably 270 GPa or less, and preferably 260 GPa or less.

  In the guide roller bearing for a film stretching machine tenter clip, the raceway member may be made of steel. In this case, the surface hardness of the track member is preferably HV680 or more. Thereby, damage to the track member when vibration or impact is applied can be suppressed.

  Preferably, in the guide roller bearing for the film stretching machine tenter clip, the rolling element has a dense layer that is a layer having higher density than the inside in a region including a rolling surface that is a surface in contact with the raceway member. ing.

  In the rolling element made of the above-described β sialon sintered body, the denseness greatly affects the rolling fatigue life. On the other hand, according to the said structure, a rolling fatigue life improves because the dense layer which is a layer denser than the inside is formed in the area | region containing a rolling surface. As a result, it is possible to provide a guide roller bearing for a film stretching machine tenter clip capable of stably ensuring sufficient durability.

  Here, the high-density layer is a layer having a low porosity (high density) in the sintered body, and can be investigated as follows, for example. First, the rolling element is cut in a cross section perpendicular to the surface of the rolling element made of β sialon sintered body, and the cross section is mirror-wrapped. Thereafter, the mirror-wrapped cross section is photographed with oblique light (dark field) of an optical microscope at, for example, about 50 to 100 times and recorded as an image of 300 DPI (Dot Per Inch) or more. At this time, the white region observed as a white region corresponds to a region with high porosity (low density). Therefore, a region where the area ratio of the white region is low is denser than a region where the area ratio is high. The recorded image is binarized using a luminance threshold using an image processing apparatus, and then the area ratio of the white area is measured, and the density of the photographed area can be known from the area ratio. .

  That is, in the guide roller bearing for a film stretching machine tenter clip, preferably, the sintered body is formed with a dense layer that is a layer having a lower area ratio of the white region than the inside in the region including the rolling surface. In addition, it is preferable to perform the said imaging | photography at 5 or more places at random, and to evaluate the said area ratio by the average value. Moreover, the area ratio of the said white area | region inside the said sintered compact is 15% or more, for example. In order to further improve the rolling fatigue life of the rolling element made of β sialon sintered body, the dense layer preferably has a thickness of 100 μm or more.

  In the guide roller bearing for a film stretching machine tenter clip, preferably, when the cross section of the dense layer is observed with oblique light of an optical microscope, the area ratio of the white region observed as a white region is 7% or less.

  By improving the denseness of the dense layer to such an extent that the area ratio of the white region is 7% or less, the rolling fatigue life of the rolling element made of the β sialon sintered body is further improved. Therefore, the durability of the guide roller bearing for the film stretching machine tenter clip of the present invention can be further improved by the above configuration.

  In the guide roller bearing for a film stretching machine tenter clip, preferably, a highly dense layer that is a denser layer than the other regions in the dense layer is formed in the region including the surface of the dense layer.

  By forming a dense layer with a higher density in the region including the surface of the dense layer, the durability of the rolling element made of β sialon sintered body against rolling fatigue is further improved, and the life of the rolling bearing is further increased. Can be improved.

  In the guide roller bearing for the film stretching machine tenter clip, preferably, the area ratio of the white region observed as a white region is 3.5% or less when the cross section of the high-density layer is observed with oblique light of an optical microscope. .

  By improving the denseness of the highly dense layer to such an extent that the area ratio of the white region is 3.5% or less, the rolling fatigue life of the rolling element made of the β sialon sintered body is further improved. Therefore, the durability of the guide roller bearing for the film stretching machine tenter clip of the present invention can be further improved by the above configuration.

  As is clear from the above description, according to the guide roller bearing for a film stretching machine tenter clip of the present invention, it is possible to improve wear resistance and corrosion resistance while suppressing a decrease in life due to a high Young's modulus. A guide roller bearing for a tenter clip can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  FIG. 1 is a schematic configuration diagram of a film stretching machine in which a rolling bearing according to an embodiment of the present invention is used. Hereinafter, with reference to FIG. 1, a film stretching machine in which a rolling bearing according to an embodiment of the present invention is used will be described.

  Referring to FIG. 1, a film stretching machine 21 in the present embodiment includes an extruder 24 that melts a thermoplastic polymer compound 22 and extrudes it as an unstretched film 23, and a cooling drum that receives the extruded film 23. 25 and means for performing the following steps. That is, a feed roller 26 that feeds the film 23 cooled by the cooling drum 25, a water tank 27 that performs humidity conditioning on the film 23 that is fed by the feed roller 26, and the film 23 that has been humidity-conditioned by the water tank 27 are sandwiched. And a water draining device 28 for removing water droplets on the surface of the film 23. Further, a biaxial stretching machine 29 that biaxially stretches the film 23 after the draining process in the longitudinal direction and the lateral direction, and a collection roller 30 that winds up the film 23 formed by the biaxial stretching machine 29 are provided. In the following, the resin raw material formed into a sheet shape in the above-described unstretched state is also defined as the film 23 as in the case of the stretched film.

  FIG. 2 is a schematic cross-sectional view showing the configuration of the transverse stretching apparatus in one embodiment of the present invention. The transverse stretching apparatus 40 shown in FIG. 2 is a component of the biaxial stretching machine 29 and is an apparatus that stretches the film 23 after the draining process in the transverse direction.

  In FIG. 2, if the unstretched film 23, which is a resin raw material formed in a sheet shape, proceeds perpendicularly to the paper surface, for example, from the back side to the front side of the paper surface, the lateral stretching device 40 is As shown in FIG. 2, a plurality of units are installed on both the left and right sides of the film 23 that is proceeding (sent). Then, the grip portions 32 of the plurality of tenter clips 31 provided in the left and right lateral stretching devices 40 sandwich the left and right sides of the sent film 23 at regular intervals. With the tenter clip 31 sandwiching the film 23, along the guide rails 33A, 33B, 33C, 33D, 34A and 34B provided from the back side to the front side of the paper surface, perpendicular to the paper surface of FIG. The tenter clip 31 is guided along each of the guide rails by continuing to proceed from the back side to the front side. As a role of a wheel for advancing (guiding) the tenter clip 31 along each guide rail, for example, guide roller bearings 1 and 2 which are deep groove ball bearings are used as shown in FIG.

  The guide roller bearing 1 that rolls on the guide surfaces of the guide rails 33A, 33B, 33C, and 33D extending in the direction along the horizontal direction is installed on the fixed shaft 37 in the direction along the horizontal direction (lateral posture). . The fixed shaft 37 may be a component fixed to the tenter clip 31, or a part of the tenter clip 31 may form the fixed shaft 37. The guide roller bearing 2 that rolls on the guide surfaces of the guide rails 34A and 34B extending in the direction along the vertical direction is installed on the fixed shaft 38 in the direction along the vertical direction (vertical posture). The fixed shaft 38 may be a component fixed to the tenter clip 31, or a part of the tenter clip 31 may form the fixed shaft 38. Therefore, the outer rings of the guide roller bearing 1 and the guide roller bearing 2 roll with respect to the fixed shaft 37 and the fixed shaft 38 by rotating on the guide surfaces of the respective guide rails like wheels.

  Here, the distance between the guide rail 33 </ b> A and the guide rail 33 </ b> B in the left-right direction in FIG. 2 continuously increases as the tenter clip 31 (that is, the film 23) travels in the traveling direction. Similarly for the distance between the guide rail 33C and the guide rail 33D and the distance between the guide rail 34A and the guide rail 34B, the distance in the left-right direction in FIG. 2 advances in the traveling direction of the tenter clip 31 (that is, the film 23). As it widens continuously.

  As the distance between the guide rail 34A and the guide rail 34B increases continuously, stress is applied to the tenter clips 31 on both the left and right sides so that the respective distances continuously increase. The guide roller bearing 1 can move along the guide rails 33A, 33B, 33C, and 33D so that the distances 31 are continuously increased. As a result, the film 23 is stretched according to the distance between the guide rail 33A and the guide rail 33B, for example, which becomes continuously wide.

  Next, the guide roller bearing 1 that is the deep groove ball bearing will be described. FIG. 3 is a schematic cross-sectional view showing a configuration of a grease-filled deep groove ball bearing as the guide roller bearing in the first embodiment. FIG. 4 is a schematic partial cross-sectional view showing an enlarged main part of FIG. 3 and 4, the guide roller bearing 1 is depicted, but the guide roller bearing 2 has the same mode.

  3 and 4, a guide roller bearing 1 which is a deep groove ball bearing includes an outer ring 11 as a first race member, an inner ring 12 as a second race member, and balls 13 as a plurality of rolling elements. The cage 14 and the seal member 15 are provided. An outer ring rolling surface 11 </ b> A as an annular first rolling surface is formed on the inner peripheral surface of the outer ring 11. On the outer peripheral surface of the inner ring 12, an inner ring rolling surface 12A as an annular second rolling surface facing the outer ring rolling surface 11A is formed. In addition, a plurality of balls 13 is formed with a ball rolling surface 13A (the surface of the ball 13) as a rolling element rolling surface. Then, the balls 13 are in contact with each of the outer ring rolling surface 11A and the inner ring rolling surface 12A at the ball rolling surface 13A, and are arranged at a predetermined pitch in the circumferential direction by the annular retainer 14, It is rotatably held on an annular track.

  The pair of seal members 15 are arranged so as to close the outer ring 11 and the inner ring 12 so as to close the space between the outer ring 11 and the inner ring 12, more specifically, the raceway space that is the space between the outer ring rolling surface 11A and the inner ring rolling surface 12A. Between the inner ring 12 and the inner ring 12, the outer ring 11 and the inner ring 12 are arranged at both ends in the width direction. With the above configuration, the outer ring 11 and the inner ring 12 of the guide roller bearing 1 are rotatable relative to each other. Moreover, the grease composition 16 is enclosed in the orbital space. 2 and 3, the guide roller bearings 1 and 2 are depicted with the cage 14 applied to only the ball 13 on one side. However, this is a convenience for explaining the sectional view and the external view. Actually, all of the sectional views are provided with a retainer 14.

Here, the balls 13 as rolling elements in the first embodiment are mainly β sialon represented by a composition formula of Si _6-Z Al _Z O _Z N _8-Z and satisfying 0.1 ≦ z ≦ 3.5. It is composed of a sintered body composed of the remaining impurities as components, and the Young's modulus is 180 GPa or more and 270 GPa or less.

  Furthermore, referring to FIG. 4, a ball dense layer 13 </ b> B that is a layer having a higher density than the inside 13 </ b> C is formed in a region including a ball rolling surface 13 </ b> A that is a rolling surface of the ball 13. When the cross section of the dense ball layer 13B is observed with oblique light from an optical microscope, the area ratio of the white region observed as a white region is 7% or less. Therefore, the guide roller bearing 1 in the present embodiment is a guide roller bearing for a film stretching machine tenter clip capable of improving wear resistance and corrosion resistance while suppressing a decrease in life due to a high Young's modulus. ing. The impurities include inevitable impurities including those derived from raw materials or those mixed in the manufacturing process.

  In the present embodiment, the balls 13 constituting the guide roller bearing 1 may be composed of a sintered body containing β sialon as a main component and the remaining sintering aid and impurities. By including a sintering aid, it is easy to provide a guide roller bearing for a film stretching machine tenter clip that can easily reduce the porosity of the sintered body and can ensure sufficient durability stably. be able to. The impurities include inevitable impurities including those derived from raw materials or those mixed in the manufacturing process.

  Furthermore, referring to FIG. 4, in the region including the ball rolling surface 13 </ b> A that is the surface of the ball dense layer 13 </ b> B, the ball high density that is a layer having a higher density than the other regions in the ball dense layer 13 </ b> B. Layer 13D is formed. When the cross section of the ball height dense layer 13D is observed with oblique light from an optical microscope, the area ratio of the white region observed as a white region is 3.5% or less. Thereby, the durability with respect to rolling fatigue of the balls 13 is further improved, and the durability of the guide roller bearing for the film stretching machine tenter clip is further improved.

  Next, a method for manufacturing a guide roller bearing for a film stretching machine tenter clip in the present embodiment will be described. FIG. 5 is a diagram showing an outline of a method for manufacturing a guide roller bearing for a film stretching machine tenter clip in an embodiment of the present invention. Moreover, FIG. 6 is a figure which shows the outline of the manufacturing method of the rolling element which consists of (beta) sialon sintered compact in embodiment of this invention.

  Referring to FIG. 5, in the method for manufacturing a guide roller bearing for a film stretching machine tenter clip in the present embodiment, first, a track member manufacturing process for manufacturing a track member, and a rolling element manufacturing process for manufacturing a rolling element, Is implemented. Specifically, in the race member manufacturing process, the outer ring 11, the inner ring 12, and the like are manufactured. On the other hand, in the rolling element manufacturing process, balls 13 and the like are manufactured.

  And the assembly process of assembling the guide roller bearing for a film stretching machine tenter clip is carried out by combining the track member manufactured in the track member manufacturing process and the rolling element manufactured in the rolling element manufacturing process. Specifically, the guide roller bearing 1 is assembled by combining, for example, the outer ring 11 and the inner ring 12 and the ball 13. And a rolling element manufacturing process is implemented using the manufacturing method of the sintered compact which consists of the following (beta) sialon sintered compact, for example.

  Referring to FIG. 6, in the method for manufacturing a rolling element made of a β sialon sintered body in the present embodiment, first, a β sialon powder preparation step of preparing β sialon powder is performed. In the β sialon powder preparation step, β sialon powder can be produced at low cost by, for example, a production step employing a combustion synthesis method.

  Next, a mixing step is performed in which a sintering aid is added to and mixed with the β sialon powder prepared in the β sialon powder preparation step. This mixing step can be omitted if no sintering aid is added.

  Next, referring to FIG. 6, a forming step is performed in which the β sialon powder or a mixture of β sialon powder and a sintering aid is formed into a schematic shape of a rolling element. Specifically, by applying a molding technique such as press molding, cast molding, extrusion molding, rolling granulation, or the like to the above β sialon powder or a mixture of β sialon powder and a sintering aid, the ball 13 Thus, a molded body formed into a general shape such as is produced.

  Next, a pre-sintering processing step is performed in which the surface of the molded body is processed so that the molded body is shaped to be closer to the shape of the desired rolling element after sintering. Specifically, by applying a processing method such as green body processing, the molded body is processed to have a shape closer to the shape of the ball 13 or the like after sintering. This pre-sintering processing step can be omitted when a shape close to the shape of the desired rolling element is obtained after sintering at the stage where the molded body is formed in the forming step.

  Next, referring to FIG. 6, a sintering step is performed in which the molded body is sintered. Specifically, for example, the molded body is heated and sintered by a heating method such as heating with an electromagnetic wave using microwaves or millimeter waves under a pressure of 1 MPa or less, so that the rough shape of the ball 13 or the like is obtained. A sintered body having the same is produced. Sintering is performed by heating the molded body to a temperature range of 1550 ° C. or higher and 1800 ° C. or lower in an inert gas atmosphere or a mixed gas atmosphere of nitrogen and oxygen. As the inert gas, helium, neon, argon, nitrogen, or the like can be employed, but nitrogen is preferably employed from the viewpoint of reducing manufacturing costs.

  Next, a finishing process for completing the rolling elements is performed by performing a finishing process in which the surface of the sintered body produced in the sintering process is processed and a region including the surface is removed. Specifically, the balls 13 as rolling elements are completed by polishing the surface of the sintered body produced in the sintering step. Through the above steps, the rolling element made of the β sialon sintered body in the present embodiment is completed.

  Here, as a result of sintering in the above-described sintering step, a region having a thickness of about 500 μm from the surface of the sintered body is denser than the inside, and when the cross section is observed with oblique light of an optical microscope, a white region is obtained. A dense layer in which the area ratio of the observed white region is 7% or less is formed. Furthermore, the region having a thickness of about 150 μm from the surface of the sintered body has a higher density than the other regions in the dense layer, and is observed as a white region when the cross section is observed with an oblique light of an optical microscope. A highly dense layer in which the area ratio of the white region is 3.5% or less is formed. Therefore, in the finishing step, it is preferable that the thickness of the sintered body to be removed is 150 μm or less particularly in a region to be a rolling surface. Thereby, a highly dense layer can remain in the region including the ball rolling surface 13A, and the rolling fatigue life of the ball 13 can be improved.

  The sintering step is preferably performed under a pressure of 0.01 MPa or higher in order to suppress the decomposition of β sialon, and more preferably performed under a pressure of atmospheric pressure or higher in consideration of cost reduction. Moreover, in order to form a dense layer while suppressing manufacturing costs, the sintering process is preferably performed under a pressure of 1 MPa or less. Further, in order to adjust the Young's modulus of the rolling element made of the β sialon sintered body to a desired value of 180 GPa or more and 270 GPa or less, for example, the z value of the β sialon powder prepared in the β sialon powder preparation step is set to 0. What is necessary is just to adjust in the range of 1 <= z <= 3.5. More specifically, the Young's modulus of the β sialon sintered body can be decreased by increasing the z value.

  Moreover, as materials of the outer ring 11 and the inner ring 12 in the first embodiment, for example, high carbon chromium bearing steel such as JIS standard SUJ2, alloy steel for machine structure such as SCM420, steel such as carbon steel for machine structure such as S53C, and the like. Can be adopted.

  In the above embodiment, the deep groove ball bearing has been described as an example of the guide roller bearing for the film stretching machine tenter clip of the present invention. However, the rolling bearing of the present invention is not limited to this, and various types such as an angular ball bearing, a needle roller bearing, etc. It can be used for a type of rolling bearing. In the above embodiment, the case where the outer ring and the inner ring are employed as the race members of the rolling bearing of the present invention has been described. However, the race member is a shaft used so that the rolling elements roll on the surface. Or a member such as a housing. That is, the raceway member should just be a member in which the rolling surface for a rolling element to roll was formed.

  Embodiment 1 of the present invention will be described below. Rolling bearings having rolling elements made of β sialon sintered bodies having various z values were produced, and tests for investigating the relationship between the z value and the rolling fatigue life (durability) were conducted. The test procedure is as follows.

  First, a method for producing a test bearing to be tested will be described. First, a β sialon powder prepared by a combustion synthesis method with a z value in the range of 0.1 to 4 is prepared, and is basically the same as the rolling element manufacturing method described in the above embodiment based on FIG. The rolling element whose z value is 0.1-4 by the method was produced. A specific manufacturing method is as follows. First, β sialon powder refined to submicron, aluminum oxide (manufactured by Sumitomo Chemical Co., Ltd., AKP30) and yttrium oxide (manufactured by HC Starck Co., Ltd., Yttrium oxide grade C) as a ball mill Were mixed by wet mixing. Then, granulation was performed with a spray dryer to produce granulated powder. The granulated powder was molded into a sphere with a mold and further pressurized by cold isostatic pressing (CIP) to obtain a spherical molded body.

  Subsequently, after performing atmospheric pressure sintering as primary sintering for the molded body, the sintered spheres are obtained by performing HIP (Hot Isostatic Press) in a nitrogen atmosphere at a pressure of 200 MPa. Manufactured. Next, lapping was performed on the sintered spheres to obtain 3/8 inch ceramic spheres (JIS grade G5). And the bearing of the JIS standard 6206 model number was produced in combination with the bearing ring made from bearing steel (JIS standard SUJ2) prepared separately (Example AJ). For comparison, a rolling element made of silicon nitride, that is, a rolling element having a z value of 0 was also produced in the same manner as the rolling element made of β sialon, and similarly assembled to a bearing (Comparative Example A).

Next, test conditions will be described. Maximum contact surface pressure P _max : 3.2 GPa, bearing rotational speed: 2000 rpm, lubrication: circulating oil supply of turbine oil VG68 (clean oil), test temperature: room temperature for the JIS standard 6206 model bearing manufactured as described above A fatigue test was performed under the conditions of The vibration of the bearing during operation is monitored by the vibration detection device, and the test is stopped when the rolling element is damaged and the vibration of the bearing exceeds a predetermined value. Recorded as bearing life. In addition, after the test was stopped, the bearing was disassembled to confirm the damaged state of the rolling elements.

  Table 1 shows the test results of this example. In Table 1, the life in each Example and Comparative Example is expressed as a life ratio with the life in Comparative Example A (silicon nitride) as 1. The damage form is described as “peeling” when peeling occurs on the surface of the rolling element, and “wearing” when the surface is worn without peeling and the test is stopped.

  Referring to Table 1, Examples A to H of the present invention in which the z value is 0.1 or more and 3.5 or less have a life comparable to that of silicon nitride (Comparative Example A). Yes. Further, the form of breakage is “peeling” as in the case of silicon nitride. On the other hand, in Example I in which the z value exceeds 3.5, the life is shortened and wear is observed on the rolling elements. That is, in Example I in which the z value is 3.8, it is considered that although the rolling element finally peeled off, the life of the rolling element was affected by the wear of the rolling element. Furthermore, in Example J in which the z value is 4, the wear of the rolling elements proceeds in a short time, and the durability of the rolling bearing is further reduced.

  As described above, when the z value is in the range of 0.1 to 3.5, the rolling bearing provided with the rolling element made of β sialon sintered body has the durability of the rolling element made of the silicon nitride sintered body. It is almost equivalent to a rolling bearing with On the other hand, if the z value exceeds 3.5, the rolling elements are likely to be worn, resulting in a decrease in the rolling fatigue life. Furthermore, it has been clarified that when the z value increases, the cause of breakage of the rolling element made of β sialon changes from “peeling” to “wear”, and the rolling fatigue life is further reduced. Thus, it was confirmed that a rolling element made of a β sialon sintered body that is inexpensive and excellent in durability can be obtained by setting the z value to 0.1 or more and 3.5 or less.

  In addition, with reference to Table 1, in Example H in which the z value exceeds 3.5, a slight amount of wear has occurred in the rolling elements, and the service life has also decreased compared to Examples A to G. ing. From this, it can be said that the z value is desirably 3 or less in order to ensure sufficient durability more stably.

  From the above experimental results, the z value is preferably 2 or less, and more preferably 1.5 or less, in order to obtain durability (life) equal to or greater than that of a rolling element made of silicon nitride. On the other hand, in view of the ease of production of β sialon powder by a production process employing combustion synthesis, it is preferable to employ a z value of 0.5 or more at which a reaction due to self-heating can be sufficiently expected.

  Embodiment 2 of the present invention will be described below. A test for producing a rolling bearing having rolling elements made of β-sialon sintered bodies having various z values and investigating the relationship between the z value and the rolling fatigue life in an environment in which an impact is applied to the rolling bearing. Was done. The test procedure is as follows.

  First, a method for producing a test bearing to be tested will be described. First, β sialon powder prepared by a combustion synthesis method with a z value in the range of 0.1 to 3.5 is prepared, and the z value is 0.1 to 3.5 by the same method as in Example 1 above. A rolling element was produced. And the bearing of the JIS standard 6206 model number was produced in combination with the bearing ring produced using the various steel materials prepared separately as a raw material (Examples AJ). As steel constituting the race, JIS standards SUJ2, SCM420, SCr420, S53C, S45C, S40C and AISI standard M50 were adopted. For comparison, a rolling element made of silicon nitride, that is, a rolling element having a z value of 0 was also produced in the same manner as the rolling element made of β sialon, and similarly assembled to a bearing (Comparative Example A).

Next, test conditions will be described. For the bearing of the JIS standard 6206 model number manufactured as described above, the maximum contact surface pressure P _max : 2.5 GPa, the bearing rotation speed: 500 rpm, lubrication: turbine oil VG68 circulating oil supply, vibration conditions: 2500 N (50 Hz), Test temperature: An excitation shock fatigue test was performed under the condition of room temperature. The vibration of the bearing during operation is monitored by the vibration detection device, and the test is stopped when the bearing is damaged and the vibration of the bearing exceeds a predetermined value. Recorded as the lifetime of. In addition, after the test was stopped, the bearing was disassembled to confirm the damaged state of the bearing.

  Table 2 shows the test results of this example. In Table 2, the life in each example and comparative example is shown in the upper part of each column as a life ratio with the life of Comparative Example A (silicon nitride) as 1 when the material of the bearing ring is SUJ2. Yes. Moreover, the damaged part (bearing ring or ball) of the bearing is described in the lower part of each column.

  Referring to Table 2, Examples C to H of the present invention having a z value of 0.5 or more and 3.0 or less clearly have a longer life than silicon nitride (Comparative Example A). Yes. Here, as shown in Table 2, the damaged part was a track member (track ring) as in the case of silicon nitride, and the damaged form was delamination. On the other hand, in Examples I and J in which the z value exceeds 3.0, the life is shortened and the rolling element (ball) is damaged (peeled) first. That is, in Example I in which the z value is 3.25, it is considered that the bearing part (ball) made of the β sialon sintered body is damaged due to the impact and the life is shortened. Furthermore, in Example J in which the z value is 3.5, the rolling elements are peeled off in a shorter time, and the durability of the rolling bearing is further reduced.

  On the other hand, in Examples A and B in which the z value is smaller than 0.5, the lifetime is reduced to substantially the same level as in Comparative Example A, and the raceway member is preceded by breakage (peeling). That is, in Example B in which the z value is 0.25, the difference in physical properties from Comparative Example A in which the z value is 0 (silicon nitride) is reduced. Therefore, the collision between the ball made of the β sialon sintered body and the race member facing the ball unilaterally causes damage on the race member side, and the same as Comparative Example A employing the ball made of the silicon nitride sintered body. It is thought that the lifetime was reduced to

  Furthermore, referring to Table 2, even when the z value is 0.5 or more and 3.0 or less, when the hardness (surface hardness) of the opposite bearing ring is less than HV680, The life tends to be shorter than when the hardness is HV680 or higher. This is thought to be because when the hardness of the raceway is low, damage to the raceway member is likely to occur due to the collision between the ball made of β sialon sintered body and the raceway member facing the ball.

  As described above, when the z value exceeds 3.0, the bearing part itself made of the β sialon sintered body is easily damaged, whereas when the z value is less than 0.5, the contact surface pressure between the mating member is low. It increases, and damage to the mating member is likely to occur. And by making z value 0.5 or more and 3.0 or less, the balance of the intensity | strength of the raw material which comprises a rolling element and the reduction of the contact surface pressure between track members is ensured. As a result, it was confirmed that the life of a rolling bearing including a rolling element made of a β sialon sintered body is improved in an environment in which an impact is applied to the bearing. In particular, when the race member is made of steel, the physical properties of the race member and the physical properties of the rolling elements are well matched, and the occurrence of damage due to impact, vibration, or the like can be suppressed. Thus, it was confirmed that the durability of the rolling bearing when vibration or impact is applied can be improved by setting the z value of β sialon constituting the rolling element to 0.5 or more and 3.0 or less. It was.

  In addition, when the race member is made of steel, it was confirmed that the surface hardness of the race member is preferably HV680 or more in order to suppress damage to the race member.

  Embodiment 3 of the present invention will be described below. A test was conducted to investigate the formation state of the dense layer and the highly dense layer of the rolling element made of β sialon constituting the rolling bearing for the CT scanner of the present invention. The test procedure is as follows.

First, a β sialon powder (product name: Melamix manufactured by Isman Jay Co., Ltd.) having a composition of Si ₅ AlON ₇ prepared by a combustion synthesis method was prepared, and the rolling element described in the above embodiment based on FIG. A cubic test piece having a side of about 10 mm was produced in the same manner as in the manufacturing method. A specific manufacturing method is as follows. First, a β sialon powder refined to submicron, aluminum oxide (manufactured by Sumitomo Chemical Co., Ltd., AKP30) and yttrium oxide (manufactured by HC Starck Co., Ltd., Yttrium oxide grade C) as a ball mill Were mixed by wet mixing. Then, granulation was performed with a spray dryer to produce granulated powder. The granulated powder was molded into a predetermined shape with a mold and further pressed by cold isostatic pressing (CIP) to obtain a molded body. Subsequently, the cube test piece was manufactured by heating and sintering the molded body at 1650 ° C. in a nitrogen atmosphere having a pressure of 0.4 MPa (atmospheric pressure sintering).

  Thereafter, the test piece was cut, and the cut surface was lapped with a diamond lapping machine, and then mirror lapping with a chromium oxide lapping machine was performed to form a cross section for observation including the center of the cube. And the said cross section was observed with the oblique light of the optical microscope (the Nikon Corporation make, Microphoto-FXA), and the 50-times-magnification instant photograph (Fujifilm Corporation FP-100B) was image | photographed. Thereafter, the obtained photographic image was taken into a personal computer using a scanner (resolution: 300 DPI). And the binarization process by a brightness | luminance threshold value was performed using the image processing software (Mitani Corporation WinROOF) (binarization separation threshold value in a present Example: 140), and the area ratio of the white area | region was measured.

  Next, test results will be described. FIG. 7 is a photograph of the cross section for observation of the test piece taken with oblique light from an optical microscope. FIG. 8 is an example showing a state in which the image of the photograph of FIG. 7 is binarized using a luminance threshold using image processing software. FIG. 9 shows an area (evaluation area) for image processing when the image of FIG. 7 is binarized by the luminance threshold value using the image processing software and the area ratio of the white area is measured. FIG. In FIG. 7, the upper side of the photograph is the surface side of the test piece, and the upper end is the surface.

  Referring to FIGS. 7 and 8, in the test piece in this example manufactured by the same manufacturing method as in the above embodiment, a layer having a white area smaller than the inside is formed in the area including the surface. I understand. Then, as shown in FIG. 9, the photographed photograph image is divided into three regions according to the distance from the outermost surface of the test piece (the region having a distance from the outermost surface within 150 μm, the region exceeding 150 μm and within 500 μm, When the area ratio of the white area was calculated by performing image analysis for each area and obtaining the area ratio of the white area, the results shown in Table 3 were obtained. Table 3 shows the average value and the maximum value of the area ratio of the white area in five fields of view obtained from five photographs taken at random with each field shown in FIG. 9 as one field of view. Yes.

  Referring to Table 3, the area ratio of the white region in the present example was 18.5% inside, whereas it was 3.7% in the region having a depth of 500 μm or less from the surface. It was 1.2% in the region where the depth from the region was 150 μm or less. From this, in the test piece in the present example produced by the above manufacturing method similar to the above embodiment, a dense layer and a highly dense layer having a white region less than the inside are formed in the region including the surface. It was confirmed.

  Embodiment 4 of the present invention will be described below. A test was conducted to confirm the rolling fatigue life of the rolling element made of a β sialon sintered body constituting the rolling bearing for the CT scanner of the present invention. The test procedure is as follows.

First, a method for producing a test bearing to be tested will be described. First, a β sialon powder (product name: Melamix manufactured by Isman Jay Co., Ltd.) having a composition of Si ₅ AlON ₇ prepared by a combustion synthesis method was prepared, and the rolling element described in the above embodiment based on FIG. A 3/8 inch ceramic sphere having a diameter of 9.525 mm was produced in the same manner as the production method described above. A specific manufacturing method is as follows. First, a β sialon powder refined to submicron, aluminum oxide (manufactured by Sumitomo Chemical Co., Ltd., AKP30) and yttrium oxide (manufactured by HC Starck Co., Ltd., Yttrium oxide grade C) as a ball mill Were mixed by wet mixing. Then, granulation was performed with a spray dryer to produce granulated powder. The granulated powder was molded into a sphere with a mold, and further pressurized by cold isostatic pressing (CIP) to obtain a spherical molded body.

  Next, the green body is processed so that the processing allowance after sintering becomes a predetermined dimension, and the green body is subsequently heated to 1650 ° C. in a nitrogen atmosphere at a pressure of 0.4 MPa. By sintering, sintered spheres were produced. Next, lapping was performed on the sintered spheres to obtain 3/8 inch ceramic spheres (rolling elements; JIS grade G5). And the bearing of the JIS standard 6206 model number was produced in combination with the bearing ring made from bearing steel (JIS standard SUJ2) prepared separately. Here, the thickness (processing allowance) of the sintered sphere removed by the lapping process on the sintered sphere was changed in eight stages, and eight types of bearings were produced (Examples A to H). On the other hand, for comparison, lapping is performed on sintered spheres (EC 141 manufactured by Nippon Special Ceramics Co., Ltd.) sintered by pressure sintering using raw material powders composed of silicon nitride and a sintering aid in the same manner as described above. Processing was performed, and a bearing of JIS standard 6206 model number was manufactured in combination with a bearing ring (JIS standard SUJ2) prepared separately (Comparative Example A). The machining allowance for lapping was 0.25 mm.

Next, test conditions will be described. Maximum contact surface pressure P _max : 3.2 GPa, bearing rotational speed: 2000 rpm, lubrication: circulating oil supply of turbine oil VG68 (clean oil), test temperature: room temperature for the JIS standard 6206 model bearing manufactured as described above A fatigue test was performed under the conditions of The vibration of the bearing during operation is monitored by the vibration detection device, and the test is stopped when the rolling element is damaged and the vibration of the bearing exceeds a predetermined value. Recorded as bearing life. The number of tests was 15 in each of the examples and the comparative examples, and after calculating the L ₁₀ life, the durability was evaluated by the life ratio with respect to Comparative Example A.

  Table 4 shows the test results of this example. Referring to Table 4, it can be said that the life of the bearings of the examples is all good considering the manufacturing cost and the like. The life of the bearings of Examples D to G in which the dense layer remains on the surface of the rolling element by setting the machining allowance to 0.5 mm or less is about 1.5 to 2 times the life of Comparative Example A. It was. Furthermore, the life of the bearings of Examples A to C in which the high-density layer remained on the surface of the rolling element by setting the machining allowance to 0.15 mm or less was about three times the life of Comparative Example A. From this, it was confirmed that the rolling bearing for CT scanner of this invention is excellent in durability. In the rolling bearing for CT scanner of the present invention, the machining cost of the rolling element made of β sialon sintered body is set to 0.5 mm or less, and the life is improved by leaving the dense layer on the surface. It was found that the lifetime was further improved by leaving the highly dense layer on the surface at 15 mm or less.

  The embodiments and examples disclosed herein are illustrative in all respects and should not be construed as being restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram of the film extending machine in which the rolling bearing in one embodiment of this invention is used. It is a schematic sectional drawing which shows the structure of the horizontal extending | stretching apparatus in one embodiment of this invention. 2 is a schematic cross-sectional view showing a configuration of a grease-filled deep groove ball bearing as a guide roller bearing in the first embodiment. FIG. FIG. 4 is a schematic partial cross-sectional view showing an enlarged main part of FIG. 3. It is a figure which shows the outline of the manufacturing method of the guide roller bearing for film stretcher tenter clips in embodiment of this invention. It is a figure which shows the outline of the manufacturing method of the rolling element which consists of (beta) sialon sintered compact in embodiment of this invention. It is the photograph which image | photographed the cross section for observation of the said test piece with the oblique light of the optical microscope. It is an example which shows the state which binarized the image of the photograph of FIG. 7 with the brightness | luminance threshold value using image processing software. It is a figure which shows the area | region (evaluation area | region) which performs an image process, when the image of the photograph of FIG. 7 is binarized with a brightness | luminance threshold value using image processing software, and the area ratio of a white area | region is measured.

Explanation of symbols

  1 guide roller bearing, 2 guide roller bearing, 11 outer ring, 11A outer ring rolling surface, 12 inner ring, 12A inner ring rolling surface, 13 balls, 13A ball rolling surface, 13B ball dense layer, 13C inside, 13D ball high dense layer , 14 Cage, 15 Seal member, 16 Grease composition, 21 Film stretcher, 22 Thermoplastic polymer compound, 23 Film, 24 Extruder, 25 Cooling drum, 26 Feed roller, 27 Water tank, 28 Drainer, 29 2 Axial stretching machine, 30 recovery roller, 31 tenter clip, 32 grip part, 33A, 33B, 33C, 33D, 34A, 34B guide rail, 37 fixed shaft, 38 fixed shaft, 40 transverse stretching device.

Claims (12)

A film stretching machine tenter clip that is disposed in contact with the guide rail between a tenter clip of the film stretching machine and a guide rail disposed to face the tenter clip, and guides the tenter clip along the guide rail. Guide roller bearing for
A track member disposed in contact with the guide rail and having an annular shape;
A rolling element that contacts the raceway member and is disposed on an annular raceway,
The rolling element is a guide roller bearing for a tenter clip for a film stretching machine, which is made of a ceramic capable of suppressing an impact on the raceway member as compared with a case where the rolling element is made of silicon nitride.   The guide roller bearing for a film stretching machine tenter clip according to claim 1, wherein the rolling element is composed of a sintered body containing β sialon as a main component and remaining impurities.   2. The guide roller bearing for a film stretching machine tenter clip according to claim 1, wherein the rolling element is composed of a sintered body mainly composed of β sialon and comprising a remaining sintering aid and impurities. The β sialon is represented by a composition formula of Si _6-Z Al _Z O _Z N _8-Z , and satisfies 0.1 ≦ z ≦ 3.5. Guide roller bearing. The β-sialon is represented by a composition formula of Si _6-Z Al _Z O _Z N _8-Z , and satisfies 0.5 ≦ z ≦ 3.0. Guide roller bearing.   The guide roller bearing for a film stretching machine tenter clip according to any one of claims 1 to 5, wherein a Young's modulus of the rolling element is 180 GPa or more and 270 GPa or less.   The guide roller bearing for a film stretching machine tenter clip according to any one of claims 1 to 5, wherein a Young's modulus of the rolling element is 220 GPa or more and 260 GPa or less. The track member is made of steel,
The guide roller bearing for a film stretching machine tenter clip according to any one of claims 1 to 7, wherein the raceway member has a surface hardness of HV680 or more.   9. The rolling element according to claim 1, wherein the rolling element has a dense layer, which is a dense layer than the inside, in a region including a rolling surface that is a surface in contact with the raceway member. A guide roller bearing for tenter clips as described in 1.   The guide roller bearing for a film stretching machine tenter clip according to claim 9, wherein an area ratio of a white region observed as a white region is 7% or less when a cross section of the dense layer is observed with oblique light of an optical microscope. .   The film stretching machine tenter according to claim 9 or 10, wherein a high-density layer, which is a layer having a higher density than other areas in the dense layer, is formed in a region including the surface of the dense layer. Guide roller bearing for clips.   The film stretcher tenter clip according to claim 11, wherein the area ratio of the white region observed as a white region is 3.5% or less when the cross section of the highly dense layer is observed with oblique light of an optical microscope. Guide roller bearing.