JP2006064035A - Double row thrust roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double row thrust roller bearing complying with high speed rotation at a low torque, and excellent in retainer formability, roller retaining force and roller incorporation performance. <P>SOLUTION: This double row thrust roller bearing is provided with an outer roller arranged on the radial outside of a bearing, an inner roller arranged on the radial inside of the bearing, and a synthetic resin retainer 403 storing and retaining the outer roller and inner roller in a pocket 405. The height H of the pocket claw 405a of the retainer 403 is not less than 0.1 mm nor more than 0.25 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thrust needle roller bearing used for an air conditioner compressor of an automobile, an automatic transmission, a manual transmission, a continuously variable transmission, an electric brake of various vehicles such as an automobile and a motorcycle. This thrust needle roller bearing is installed in the rotating part of these parts or devices, and is used to support the thrust load applied to the rotating part.

  A thrust needle roller bearing, which is a typical example of a thrust roller bearing, includes a plurality of needle rollers disposed between a pair of opposed raceway members and a cage, and has a simple structure and a high load capacity and high load. It is known that it can achieve rigidity. Further, thrust needle roller bearings have advantages such as a small axial height (thickness), and are therefore widely used in applications that require space saving.

  The main application where thrust needle roller bearings are used is compressors for automotive air conditioners. Japanese Patent Laid-Open No. 2003-97562 (Patent Document 1) discloses various types of compressors. For example, as shown in FIG. 1, a double swash plate type in which the piston 510 is reciprocated by a double-sided inclined plate 509 fixed to the input rotating shaft 508, and as shown in FIG. 2, a single-sided inclined plate 612 fixed to the input rotating shaft 611 A single swash plate type in which the piston 614 is reciprocated through the rod 613, and a variable in which the piston 718 is reciprocated through the rod 717 by a swash plate 716 attached to the input rotating shaft 715 in a variable angle as shown in FIG. There is a capacity swash plate type.

  As a specific bearing use example, in the case of the both swash plate type of FIG. 1, a needle roller bearing 519 with a cage and a thrust needle roller bearing 520 are used. The swash plate type in FIG. 2 uses a shell needle roller bearing 621 and a thrust needle roller bearing 622. Further, the variable capacity swash plate type of FIG. 3 uses a needle roller bearing 723 with a cage and a thrust needle roller bearing 724. As described above, the thrust needle roller bearing has advantages such as a low cross-sectional height, and therefore is used for applications such as compressors that require space saving.

  Another application in which thrust needle roller bearings are used is electric brakes. Electric brakes for various vehicles are disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-247576 (Patent Document 2) and Japanese Patent Application Laid-Open No. 2000-238628 (Patent Document 3).

  In the electric brake disclosed in Japanese Patent Application Laid-Open No. 2003-247576, an advance / retreat operation mechanism is provided for advancing / retreating by the driving force of the electric motor to generate a pressing force on the pressing member of the friction pad. Is pressed and slid to perform braking. The electric brake includes a reduction gear mechanism that decelerates the driving force of the electric motor and transmits it to the advance / retreat operation mechanism. A reduction gear mechanism is disposed between the electric motor and the friction pad.

  In the electric brake described above, the reduction gear mechanism includes a planetary arm that is rotationally driven by an electric motor, a planetary gear that is rotatably supported on the outer periphery of the planetary arm, and a sun gear that has external teeth that mesh with the planetary gear. And a reduction gear disposed so as to face the sun gear, and a ball screw nut that rotates integrally with the reduction gear. A thrust needle roller bearing is disposed between the sun gear and the reduction gear on which the thrust load acts.

Japanese Patent Application Laid-Open No. 2000-238628 discloses a brake force holding device that can hold and release a brake force under certain conditions such as a temporarily stopped state of a vehicle and a parking brake operation. Also in the device disclosed in this publication, bearings are arranged at portions that relatively rotate while receiving a thrust load.
JP 2003-97562 A JP 2003-247576 A JP 2000-238628 A

  In the thrust needle roller bearing, differential slip occurs between the roller and the raceway because of its basic structure. More specifically, in the case of a thrust needle roller bearing, a cylindrical needle roller is arranged as a rolling element on a raceway having a flat raceway surface, and the roller and the raceway surface are in line contact. It has become. The center of rotation of the bearing coincides with the center of revolution of the roller. Although the roller has a predetermined length in the radial direction of the bearing, the peripheral speed on the rolling surface of the roller is the same speed. On the other hand, the circumferential speed of the raceway surface of the race which is in rolling contact with the roller increases from the center of rotation of the bearing toward the outer diameter direction. Therefore, the peripheral speed difference between the roller and the raceway surface of the raceway is maximized at both ends of the roller.

  Theoretically, pure rolling motion is performed only on the pitch circle of the bearing, and the peripheral speed difference between the roller and the raceway surface increases from the point on the pitch circle toward both ends of the roller, and differential slip increases. . This differential slip increases in proportion to the length of the roller.

  The differential sliding in thrust needle roller bearings is large compared to other types of bearings. Therefore, due to differential slip, edge stress is likely to occur between the roller edge and the bearing ring, and surface-origin separation is likely to occur at the edge of the roller rolling part of the bearing ring. .

  Further, when a differential slip occurs in the needle roller, the oil film is cut, and the roller and the race are in metal contact and generate heat. This heat generation tends to cause surface damage and surface-origin peeling. Such a tendency becomes more remarkable as the rotation speed becomes higher. As a result, it is recognized that the bearing life is shortened.

  As a measure for alleviating the effect of differential slip between the roller and the raceway surface of the raceway, it is conceivable to shorten the length of the roller. However, if the length of the roller is simply shortened, the contact area of the roller becomes small, so that the contact surface pressure of the roller increases and there is a possibility that problems such as early peeling occur on the outer surface of the roller.

  Conventional cages for thrust needle roller bearings include a steel type and a resin type. In the case of the steel cage, since the weight is large, the inertia weight (inertial mass) of the cage that rotates while holding the roller is increased, and for example, torque loss of a compressor for an air conditioner is increased. As a result, fuel consumption is reduced. Moreover, since the friction between the steel cage and the needle rollers is large, torque and noise when the needle rollers roll are increased.

  Resin cages are generally made by injection molding. When the height of the pocket claw of the cage is small, good cage moldability can be obtained, but the holding force of the rollers becomes inferior. On the other hand, when the height of the pocket claw is large, the roller holding force is excellent, but the cage moldability and the roller assembling property are inferior.

  An object of the present invention is to provide a double-row thrust roller bearing that can cope with high-speed rotation with low torque, and that is excellent in cage formability, roller holding force, and roller incorporation.

  A double-row thrust roller bearing according to the present invention accommodates an outer roller disposed on the outer side in the radial direction of the bearing, an inner roller disposed on the inner side in the radial direction of the bearing, and the outer roller and the inner roller in a pocket. And holding the synthetic resin cage, the pocket claw height of the cage being 0.1 mm or more and 0.25 mm or less.

  Synthetic resin cages are lighter and more self-lubricating than steel cages. Therefore, the double row thrust roller bearing provided with the synthetic resin cage has lower torque and lower noise than the bearing provided with the steel cage. Further, by arranging double rows of rollers in the radial direction, differential sliding can be suppressed and the torque of the bearing can be reduced. In the present invention, since the pocket claw height of the synthetic resin cage is 0.1 mm or more and 0.25 mm or less, it is excellent in cage moldability, roller holding force, and roller mounting property. If the pocket claw height is less than 0.1 mm, the roller holding force is inferior. On the other hand, if the pocket claw height exceeds 0.25 mm, the cage moldability and the roller mounting property are inferior.

  In one embodiment, the retainer includes a plurality of pockets provided at intervals in the circumferential direction, and an outer roller and an inner roller are accommodated in each of the plurality of pockets.

  In another embodiment, the cage is spaced circumferentially at a plurality of outer pockets spaced circumferentially at a radially outer position of the bearing and at a radially inner position of the bearing. A plurality of inner pockets, outer rollers are accommodated in each of the plurality of outer pockets, and inner rollers are accommodated in each of the plurality of inner pockets.

  Preferably, the cage is made of a synthetic resin mainly composed of polyphenylene sulfide and including glass fibers. In this case, more preferably, the cage includes 20% or more glass fiber by weight.

  As another embodiment, the cage is made of a synthetic resin mainly composed of polyphenylene sulfide and including carbon fibers. In this case, more preferably, the cage includes 20% or more of carbon fiber by weight.

  The inventor of the present application investigated the amount of drilling wear of the cage by changing the material of the resin forming the cage, the glass fiber amount, and the carbon fiber amount. As a result, it has been found that a cage mainly composed of polyphenylene sulfide has a lower drilling wear amount than a cage mainly composed of other synthetic resins (for example, polyethersulfone, nylon 66). Furthermore, in cages mainly composed of polyphenylene sulfide, those containing 20% or more glass fiber or 20% or more carbon fiber on a weight basis were found to exhibit better resistance to drilling wear.

  If the synthetic resin forming the cage further contains polytetrafluoroethylene, drilling wear is further reduced. The inventors of the present application have also found that drilling wear is small even in the case of a cage mainly composed of polyetheretherketone.

  When a double-row thrust roller bearing with the above configuration is used in an air conditioner compressor, transmission (automatic / manual), continuously variable transmission, electric brake of a vehicle, etc., a plurality of rollers are arranged in the radial direction of the bearing. Therefore, differential sliding of the roller can be suppressed, and metal contact between the roller and the raceway member is prevented, and heat generation of the bearing portion is suppressed. Thus, it is possible to cope with high speed rotation. Further, since surface damage and surface-originating peeling can be prevented, the durability of the bearing can be improved. In addition to these advantages, low torque and low noise can be realized by using a cage made of synthetic resin as described above.

  Paying attention to the end face shape of the roller, the outer roller has an F end face (plane) or an A end face (round face), and the inner roller has an F end face or an A end face. Accordingly, there are four combinations of the end face of the outer roller and the end face of the inner roller: F end face and F end face, A end face and A end face, A end face and F end face, and F end face and A end face.

  Paying attention to the length of the roller, the length of the outer roller and the inner roller may be the same, the outer roller may be longer than the inner roller, or the outer roller may be shorter than the inner roller. .

  Double row thrust roller bearings as described above can improve peeling life and bearing durability compared to conventional single row roller type thrust bearings, so the size of the rollers can be reduced and the number of rollers can be reduced. You can make it. When a plurality of rollers are arranged in one pocket of the cage, the number of rollers is not reduced, but the number of pockets is reduced. Accordingly, it is possible to reduce the weight and size of the bearing. In other words, as long as the bearings have the same size, the double row roller type thrust bearing can cope with a higher load condition than the conventional single row roller type thrust bearing.

  Preferably, the end face runout accuracy of the outer roller and the inner roller is 30 μm or less. With such end face accuracy, the frictional resistance between the roller and the cage is reduced. Further, when the inner and outer rollers are accommodated in one pocket of the cage, the frictional resistance between the outer roller and the inner roller is reduced. Therefore, drilling wear due to friction at the time of contact is less likely to occur, and the bearing sound is also reduced. Drilling wear means abnormal wear that occurs when the end face of the needle roller is pressed against the wall surface of the pocket of the cage by centrifugal force, and contact by the rotation of the needle roller is added.

  The double-row thrust roller bearing according to the present invention is used for an air conditioner compressor of an automobile, a transmission (automatic / manual), a continuously variable transmission, an electric brake of various vehicles such as an automobile and a motorcycle. In the case of the swash plate type compressor shown in FIG. 1, the double-row thrust roller bearing according to the present invention is used as the thrust needle roller bearing 520. In the case of the swash plate type compressor shown in FIG. 2, a double row thrust roller bearing according to the present invention is used as the thrust roller bearing 622. The raceway surface of the thrust roller bearing 622 is directly formed on the surfaces of the single-side inclined plate 612 and the rod support member 615. In the case of the variable displacement swash plate type compressor shown in FIG. 3, a double row thrust roller bearing according to the present invention is used as the thrust needle roller bearing 724.

  FIGS. 4 and 5 show embodiments of double-row thrust roller bearings used for a compressor for an air conditioner, a transmission (automatic / manual), a continuously variable transmission, an electric brake, and the like, respectively. Moreover, FIGS. 6-20 has each shown the arrangement | positioning form of a different roller. In these drawings, the same reference numerals indicate the same or corresponding elements. Further, in these drawings, the bearing ring or the bearing member of the bearing is not shown.

  First, the basic structure of a double row thrust roller bearing will be described with reference to FIGS. The double-row thrust needle roller bearing is disposed between a stationary side race ring (track member) (not shown), a rotation side race ring (track member) (not shown), and both race rings by a cage 301. A plurality of rollers 302 and 303 are provided. A plurality of rollers 302 and 303 are arranged in the radial direction of the bearing. The roller 302 is disposed inside as viewed in the radial direction, and the roller 303 is disposed outside as viewed in the radial direction. Therefore, in the following description, they are referred to as an inner roller 302 and an outer roller 303. In the embodiment shown in FIG. 4, the inner roller 302 and outer roller 303 are housed in a common pocket of the cage, and in the embodiment shown in FIG. 5, the inner roller 302 and outer roller 303 are in separate pockets of the cage. Contained.

  In one embodiment, the cage 301 is made of a synthetic resin mainly composed of polyphenylene sulfide and including glass fibers. A preferable content of the glass fiber is 20% or more based on weight. In another embodiment, the cage 301 is made of a synthetic resin mainly composed of polyphenylene sulfide and including a carbon fiber. A preferable content of the carbon fiber is 20% or more by weight. In yet another embodiment, the cage is made of polyetheretherketone.

  In the illustrated embodiment, the cage 301 is preferably guided by the rolling elements 302 and 303 so as not to contact a pair of track surfaces (track members) (not shown). In other words, the outer roller 303 and the inner roller 302 hold the retainer 301 so as not to contact the pair of raceway surfaces. A raceway having a raceway surface may be used as a component part of a double row thrust roller bearing, or a counterpart member that is supported by rolling as shown in FIG. 2 may have a raceway surface directly.

Focusing on dimensional relationships, to the retainer 301 and the rolling element guide, preferably, a height dimension T ₁₀ of the retainer 301 along the rotation axis direction of the bearing, the diameter of the inner roller 302 and outer roller 303 smaller than the T _20.

  Thus, by using the cage 301 as a rolling element guide so that the cage 301 and the raceway surface (track member) do not come into contact with each other, the heat generation of the bearing portion can be more effectively suppressed.

  In the roller arrangement form shown in FIG. 6, the cage 301 includes a plurality of pockets 311 provided at intervals in the circumferential direction, and an inner roller 302 and an outer roller 303 are arranged in each pocket 311. .

  With reference to FIGS. 21 to 25, the detailed structure of a double-row thrust roller bearing used in a compressor for an air conditioner, a transmission (automatic / manual), a continuously variable transmission, an electric brake, etc. of an automobile will be described as an example. .

  FIG. 21 shows a double row thrust roller bearing 401 provided with a resin cage 403. The cage 403 has a plurality of rectangular pockets 405 longer than the radial length L of the rollers 402. On both side edges of each pocket 405, pocket claws (roller holding portions) 405a and 405b projecting in opposite directions are formed. The rollers 402 are held by these pocket claws (roller holding portions) 405a and 405b. When assembling the rollers 402 a and 402 b into the cage 403, the rollers get over the pocket claw 405 a on the outer diameter surface side from the outside of the cage 403 and are mounted in the pocket 405.

  22 is an enlarged plan view of the pocket portion of FIG. 21, and FIG. 23 is a cross-sectional view taken along line IV-IV of FIG. The needle rollers 402 are configured by needle rollers 402 a on the outer diameter side and needle rollers 402 b on the inner diameter side, and are arranged in double rows in the pocket 405.

  Here, the length La in the radial direction of the pocket claws (roller holding portions) 405a and 405b is formed shorter than the roller length L, so that the pocket claws (roller holding portions) 405a and 405b are formed at both ends. Lubricating oil can be easily passed through the recess 405c.

  The synthetic resin cage 403 is manufactured by injection molding. FIG. 25 is a diagram showing an injection molding process. In this figure, the left half of the figure shows a state in which synthetic resin is injected between the fixed mold 421 and the mold 420 and solidified. The right half of the figure shows a state in which the mold 420 has been extracted upward after the synthetic resin forming the cage 403 has solidified. As is clear from this figure, the mold 420 is forcibly removed by overcoming the pocket pawl 405a on the outer diameter surface side of the cage 403. When the height H of the pocket claw 405a is small, the shape of the pocket claw 405a is not impaired even if the mold 420 is forcibly removed. However, when the height H of the pocket claw 405a is small, the holding force of the rollers accommodated in the pocket 405 becomes inferior. On the other hand, if the height H of the pocket claw 405a is increased, the roller retainability is improved, but when the mold 420 is forcibly removed, the shape of the pocket claw 405a is destroyed. That is, the moldability of the cage 403 is impaired. If the height H of the pocket claw 405a is too large, the roller cannot be easily assembled into the pocket 405.

  The inventors of the present invention made a plurality of synthetic resin cages having different heights H of the pocket claws 405a, and investigated their cage moldability, roller holding force, and roller mounting property. The results are shown in Table 1 below.

  When the height H of the pocket claw 405a was less than 0.1 mm, the cage moldability was particularly excellent, and no problem was found in the roller assemblability. However, the holding power of the roller accommodated in the pocket 405 was inferior.

  When the height H of the pocket claw 405a exceeds 0.25 mm, the roller holding force is particularly excellent, but when the mold 420 is forcibly removed, the shape of the pocket claw 405a collapses. Also, the roller cannot be easily assembled.

  When the height H of the pocket claw 405a was set to 0.1 mm or more and 0.25 mm or less, no problem was found in cage moldability, roller mounting property, and roller holding force. Therefore, the optimum height H of the pocket claw 405a is not less than 0.1 mm and not more than 0.25 mm.

  FIG. 24 is a partial cross-sectional view for explaining a use state of the double row thrust roller bearing in one embodiment of the present invention. The double row thrust roller bearing 401 has a clearance with the inner end 403a of the cage 403 as a guide surface so that the roller 402 rolls between the raceway surface 409a of the rotating shaft 409 and the raceway surface 410a of the fixed shaft 410. Fit. When the rotating shaft 409 rotates, the cage 403 also rotates with the rotating shaft 409, and the roller 402 rolls between the track surface 409a of the rotating shaft 409 and the track surface 410a of the fixed shaft 410. Here, the lubricating oil is supplied into the double row thrust roller bearing 401 via an oil passage from a hydraulic supply source (not shown).

  After the lubricating oil passes through the oil passage as indicated by arrow a, it is between the raceway surface 410a of the fixed shaft 410 and the radially inner portion with respect to the pocket pawl (roller holding portion) 405b on the lower side of the cage 403. Through as shown by arrow b. Thereafter, the lubricating oil passes through the periphery of the roller 402 and the space formed by the cage 403 as indicated by an arrow c, so that the side surface of the roller 402 and the pocket claws (roller holding portions) 405a and 405b of the cage 403 are formed. And between the end surfaces of the rollers 402 and between the side surfaces of the rollers 402 and the raceway surfaces 409a and 410a. And between the raceway surface 410a of the fixed shaft 410 and the outer portion in the radial direction with respect to the pocket claw (roller holding portion) 405b of the cage 403, and between the raceway surface 409a of the rotary shaft 409 and the pocket claw of the cage 403. (Roller holding portion) 405a is discharged between the radially outer portions as indicated by an arrow d.

  In one embodiment, the cage 403 is made of a synthetic resin containing glass fiber in polyphenylene sulfide. Polyphenylene sulfide does not hydrolyze, so when thrust roller bearings are used in a moisture-rich atmosphere, the cage is difficult to absorb moisture, preventing dimensional changes and strength reduction of the cage. Is done. Moreover, since glass fiber has high mechanical strength, the strength and heat resistance of the cage can be improved by including the glass fiber. In addition, a synthetic resin containing glass fibers in polyphenylene sulfide is easily melted by heating and is easily solidified by cooling, and thus is suitable for manufacturing a cage by injection molding. Furthermore, since synthetic resin including glass fibers in polyphenylene sulfide is excellent in chemical resistance and oil resistance, it becomes possible to use a thrust needle roller bearing in an atmosphere where chemicals or oil adheres.

  In another embodiment, the cage 403 is made of a synthetic resin including carbon fiber in polyphenylene sulfide. Even with such a cage, the same effects as described above can be obtained.

  As another form which arrange | positions an inner side roller and an outer side roller, there exists a thing as shown in FIGS. 7 to 20, illustration of the inner roller and the outer roller is omitted. The cage 301 shown in FIG. 7 has a plurality of outer pockets 312 provided at intervals in the circumferential direction at positions outside the bearing in the radial direction, and a gap in the circumferential direction at positions inside the bearing in the radial direction. A plurality of inner pockets 313, outer rollers 303 are accommodated in each of the plurality of outer pockets 312, and inner rollers 302 are accommodated in each of the plurality of inner pockets 313. In the form shown in FIG. 7, the number of inner rollers 302 is the same as the number of outer rollers 303.

  As in the cage shown in FIG. 7, the cage 301 shown in FIG. 8 includes a plurality of outer pockets 312 provided at circumferentially spaced positions in the radial outer position of the bearing, and the radial direction of the bearing. A plurality of inner pockets 313 provided at intervals in the circumferential direction at an inner position of each of the plurality of outer pockets. Each of the plurality of outer pockets 312 accommodates an outer roller 303, and each of the plurality of inner pockets 313 includes an inner roller 302. Is housed. In the form shown in FIG. 8, the number of inner rollers 302 is different from the number of outer rollers 303. Specifically, in the illustrated form, the number of outer rollers 303 is greater than that of inner rollers 302.

  In the cage 301 shown in FIG. 9, the number of outer rollers 303 and the number of inner rollers 302 are the same, and the outer rollers 303 are positioned on a line extending in the radial direction through the center of the adjacent inner rollers 302. Yes.

  In the cage 301 shown in FIG. 10, the number of the outer rollers 303 and the number of the inner rollers 302 are the same, and the outer rollers 303 and the inner rollers 302 are in a positional relationship shifted in the radial direction. Unlike the embodiment shown in FIG. 9, the outer roller 303 is not positioned on a line extending in the radial direction through the center of the adjacent inner roller 302, and the inner roller 302 also has the center of the adjacent outer roller 303. It is not located on a line extending radially through.

  In the cage 301 shown in FIG. 11, the number of the inner rollers 302 is twice the number of the outer rollers 303, and the outer rollers 303 have a positional relationship aligned with the other inner rollers 302 in the radial direction. .

  In the cage 301 shown in FIG. 12, the number of the inner rollers 302 is twice the number of the outer rollers 303, and the line extending in the radial direction through the center of the adjacent outer rollers 303 is a column between the adjacent inner rollers. It passes through the center of the club.

  In the cage 301 shown in FIG. 13, the number of the inner rollers 302 is twice the number of the outer rollers 303, and the outer rollers 303 and the inner rollers 302 have a positional relationship shifted in the radial direction. Unlike the embodiment shown in FIG. 12, the outer roller 303 is not positioned on a line extending in the radial direction through the center of the adjacent inner roller 302, and the inner roller 302 also has the center of the adjacent outer roller 303. It is not located on a line extending radially through.

  In the cage 301 shown in FIG. 14, the number of the outer rollers 303 is twice the number of the inner rollers 302, and the inner rollers 302 have a positional relationship aligned with the other outer rollers 303 in the radial direction.

  In the cage 301 shown in FIG. 15, the number of the outer rollers 303 is twice the number of the inner rollers 302, and the line extending in the radial direction through the center of the adjacent inner rollers 302 is between the adjacent outer rollers 303. It passes through the center of the pillar.

  In the cage 301 shown in FIG. 16, the number of the outer rollers 303 is twice the number of the inner rollers 302, and the inner rollers 302 and the outer rollers 303 are in a positional relationship shifted in the radial direction. Unlike the embodiment shown in FIG. 15, the inner roller 302 is not positioned on a line extending in the radial direction through the center of the adjacent outer roller 303, and the outer roller 303 also has the center of the adjacent inner roller 302. It is not located on a line extending radially through.

  In the cage 301 shown in FIG. 17, double row rollers 302 and 303 accommodated in one pocket and single row rollers 304 are alternately arranged in the circumferential direction. The single row roller 304 has a positional relationship aligned with the outer roller 303 in the circumferential direction.

  In the cage 301 shown in FIG. 18, double row rollers 302 and 303 and single row rollers 305 accommodated in one pocket are alternately arranged in the circumferential direction, and the single row rollers 305 are seen in the radial direction. Thus, it is located at the center of the double row rollers 302 and 303.

  In the cage 301 shown in FIG. 19, double row rollers 302 and 303 and single row rollers 306 accommodated in one pocket are alternately arranged in the circumferential direction. And the positional relationship aligned in the circumferential direction.

  In the cage 301 shown in FIG. 20, double row rollers 302 and 303 accommodated in one pocket and double row rollers 307 and 308 accommodated in another pocket are alternately arranged in the circumferential direction.

  6 to 20, two rollers are arranged in the radial direction, but three or more rollers may be arranged in the radial direction. Further, the thrust needle roller bearing does not necessarily have the fixed-side raceway and the rotation-side raceway, and may have a structure having a rolling surface directly on the other side of the member to be incorporated.

  When attention is paid to the end face shapes of the outer roller 303 and the inner roller 302, the outer roller has an F end face (plane) or an A end face (round face), and the inner roller has an F end face or an A end face. Therefore, there are the following four combinations of the end face of the outer roller and the end face of the inner roller.

  (1) The outer roller 303 is an F end surface, and the inner roller 302 is an F end surface.

  (2) The outer roller 303 is an F end surface, and the inner roller 302 is an A end surface.

  (3) The outer roller 303 is the A end surface, and the inner roller 302 is the F end surface.

  (4) The outer roller 303 is the A end surface, and the inner roller 302 is the A end surface.

  When attention is paid to the lengths of the outer roller 303 and the inner roller 302, they are usually set to the same length. However, depending on the use conditions, the lengths of both may be different. Specifically, the length of the inner roller 302 may be longer than that of the outer roller 303 under use conditions where the surface pressure increases. Moreover, the length of the outer side roller 303 may be made longer than the inner side roller 302 on the use conditions in which roller slip becomes large.

  When attention is paid to the shape of the roller holding portion of the cage, it is preferable that the corner portion holding the roller from the side surface is smoothly slid. If the roller is held by such a loose holding portion, the roller can be stably guided and held without cutting the lubricating oil film.

  When attention is paid to the shape of the rollers, crowning may be formed on at least one of the outer roller 303 and the inner roller 302. In this way, the addition of the crowning shape can shorten the effective length of the roller and enhance the differential slip reduction effect. Furthermore, there is an effect of reducing the load on the edge portion in the crowning shape, and the friction torque of the bearing can be reduced.

  The end face runout accuracy of the outer roller and the inner roller is preferably 30 μm or less. If the end face runout accuracy is 30 μm or less, the contact friction resistance between the rollers and the contact friction resistance between the rollers and the cage are reduced, and drilling wear hardly occurs.

If having a double row thrust roller bearing raceway, the bearing ring, at least to a depth of a surface layer 0.1 mm 10000 per unit area particle size 0.6μm or more carbide / mm ² or more and less than 40000 / mm ² You may make it have. In such a race, since carbides act as deformation resistance, the material strength of the surface layer is improved. Furthermore, the occurrence of plastic flow can be suppressed even if the raceway surface generates heat due to differential sliding between the rollers and the raceway or poor lubrication.

  The inventor of the present application investigated the amount of drilling wear of the cage by changing the material of the resin forming the cage, the glass fiber amount, and the carbon fiber amount. The test conditions were as follows.

Load: 3500N
Rotational speed: 7500 r. / Min.
Lubrication: Idemitsu ATF-DX 140 ° C
The test results are shown in FIG. The names of resins and the like abbreviated in FIG. 26 are as follows.

PPS: Polyphenylene sulfide GF: Glass fiber CF: Carbon fiber PTFE: Polytetrafluoroethylene PEEK: Polyetheretherketone PES: Polyethersulfone As is clear from the results of FIG. 26, PPS (polyphenylene sulfide) is mainly held In the case of a vessel, the amount of drilling wear is greatly reduced compared to a cage mainly composed of PES (polyethersulfone) or nylon 66.

  Further, in the cage mainly composed of PPS (polyphenylene sulfide), it is recognized that the drilling wear amount is further reduced when the glass fiber amount or the carbon fiber amount is 20% or more on the weight basis. In addition, when the cage contains PTFE (polytetrafluoroethylene), it is recognized that the amount of drilling wear is further reduced.

  In the case of an iron cage, a relatively good amount of drilling wear is shown, but because the weight is large, the inertia weight of the cage that rotates while holding the rollers increases, which may increase torque loss and fuel consumption. There is. Further, compared with the resin cage, the friction between the cage and the cage is large, and the torque and noise when the rollers roll are increased.

  In the case of a resin cage mainly composed of PEEK (polyetheretherketone), the amount of drilling wear is relatively small. However, the resin cage mainly composed of PEEK has a disadvantage that the cost becomes very high. For example, it is made of PEK (polyphenylene sulfide), contains 20% or more glass fiber by weight, and contains PTEK (polytetrafluoroethylene). The vessel costs over 4 times.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and changes can be made to the illustrated embodiment within the same range as the present invention or within an equivalent range.

  The present invention can be advantageously applied as a double-row thrust roller bearing used for a compressor for an air conditioner of an automobile, a transmission (automatic / transmission), a continuously variable transmission, an electric brake of a vehicle, and the like.

It is a longitudinal section showing a swash plate type compressor for an air conditioner. It is a longitudinal section showing a swash plate type compressor for an air conditioner. It is a longitudinal section showing a variable capacity swash plate type compressor for an air conditioner. It is sectional drawing which shows one form of the double row thrust roller bearing which concerns on this invention. It is sectional drawing which shows the other form of the double row thrust roller bearing which concerns on this invention. It is a top view which shows an example of the arrangement | positioning form of a some roller. It is a top view which shows the other example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller. It is a principal part perspective view of a holder | retainer. It is the top view which expanded the pocket part of the holder | retainer. It is sectional drawing along the IV-IV line of FIG. It is a fragmentary sectional view explaining the use condition of a double row thrust roller bearing. It is a figure for demonstrating the injection molding process of a holder | retainer. It is a figure which shows the relationship between the material of a holder | retainer, and drilling wear amount.

Explanation of symbols

301 cage, 302 inner roller, 303 outer roller, 311 pocket, 312 outer pocket, 313 inner pocket, 403 cage, 405 pocket, 405a, 405b pocket claw, 420 mold, 421 fixed mold, H pocket claw height.

Claims (9)

An outer roller disposed outside the bearing in the radial direction;
An inner roller disposed inside the bearing in the radial direction;
A synthetic resin cage that holds and holds the outer roller and the inner roller in a pocket;
A double row thrust roller bearing, wherein a pocket claw height of the cage is 0.1 mm or more and 0.25 mm or less. The cage includes a plurality of pockets provided at intervals in the circumferential direction,
The double row thrust roller bearing according to claim 1, wherein the outer roller and the inner roller are accommodated in each of the plurality of pockets. The cage includes a plurality of outer pockets spaced circumferentially at positions radially outside the bearing, and a plurality spaced circumferentially at positions radially inside the bearing. Including the inside pocket,
The outer rollers are accommodated in each of the plurality of outer pockets,
The double row thrust roller bearing according to claim 1, wherein the inner rollers are accommodated in each of the plurality of inner pockets. The double row thrust roller bearing according to any one of claims 1 to 3, wherein the cage is made of a synthetic resin mainly composed of polyphenylene sulfide and including glass fibers. The double row thrust roller bearing according to claim 4, wherein the cage includes 20% or more glass fiber by weight. The double row thrust roller bearing according to any one of claims 1 to 3, wherein the cage is made of a synthetic resin mainly composed of polyphenylene sulfide and including a carbon fiber. The double row thrust roller bearing according to claim 6, wherein the cage includes 20% or more of carbon fiber on a weight basis. The double row thrust roller bearing according to any one of claims 4 to 7, wherein the synthetic resin forming the cage further contains polytetrafluoroethylene. The double row thrust roller bearing according to any one of claims 1 to 3, wherein the cage is made of polyetheretherketone.

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