JP2008190652A - Rolling bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing device enabling the saving of energy when a preload is applied thereto by using a fluid pressure such as an oil pressure. <P>SOLUTION: When a fluid pressure in a fluid supply passage is higher than a first set pressure, a fluid in the fluid supply passage 48 is supplied to a pressure chamber 45 via a check valve 44, and when the pressure in the pressure chamber 45 becomes lower than the first set pressure, the fluid is supplied from a hydraulic pump 49 to the pressure chamber 45 via the check valve 44. When the pressure in the pressure chamber 45 becomes higher than a second set pressure, the fluid is discharged from the pressure chamber 45 via a relief valve 50, and also when the pressure in the pressure chamber becomes higher than a third set pressure which is higher than the first set pressure but is lower than the second set pressure, the supply of the fluid is stopped by a fluid supply control part 60. With this system, the pressure in the pressure chamber 45 is maintained at a level between the first and second set pressures without always supplying the fluid from the hydraulic pump 49 into the pressure chamber 45. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rolling bearing device that is used with a preload applied, such as a conical roller bearing or an angular ball bearing.

  Tapered roller bearings and angular contact ball bearings are used with axial preload applied. For example, in a gear-type drive transmission unit for an automobile such as a transmission unit, a tapered roller bearing is adopted at its main point (for example, a final reduction gear portion in the transmission unit). As shown in FIG. 3 (a), the tapered roller bearing 111 press-fits the rotating shaft 115 into the inner ring 133, fits the outer ring 132 into the bearing housing 125 of the transmission case, and then axially one side ( Preload is applied in the direction of arrow a). When the preload is applied in this manner, the outer ring 132 receives a component force on the inclined rolling surface of the tapered roller 134 and is displaced in the axial direction and the radial direction, and the left end surface 132 c and the outer peripheral surface 132 b are connected to the housing 125. The preload is supported by being pressed against the inner end face 125c and the inner peripheral face 125a.

On the other hand, as a part of weight reduction in recent years, a transmission case is made of a light metal such as an aluminum (Al) alloy. Al has the highest linear expansion coefficient among structural materials (about 23.5 × 10 ⁻⁶ / ° C. at room temperature: hereinafter, the unit of linear expansion coefficient is abbreviated as ppm / ° C.) and constitutes a rotating shaft and a tapered roller bearing. There is a considerable difference from the linear expansion coefficient of steel (Fe-based material) (about 12 ppm / ° C. at room temperature).

When the rotating shaft and the housing are made of the same material, the dimensional change due to temperature is the same, so there is no significant change in the preload applied to the tapered roller bearing. However, if the housing is made of a light metal, the housing may change in size more than the rotating shaft due to temperature rise, and the preload may be lost.
Specifically, as shown in FIG. 3B, when the temperature of the transmission rises, the housing 125 and the rotating shaft 115 expand, but due to the difference in dimensions due to the expansion, the inner circumferential raceway surface 132a of the outer ring 132 changes. It moves away from the rolling surface of the tapered roller 134 in the direction of arrow b. That is, the axial gap and the radial gap of the tapered roller bearing 111 vary greatly depending on the temperature, resulting in insufficient preload. Such a shortage of preload causes gear rattle and causes noise.

  In order to solve such a problem, Patent Document 1 below discloses a rolling bearing device in which a preload is applied to an outer ring by hydraulic pressure or a spring. Specifically, a cylindrical cylinder with a bottom is formed in the housing, and an outer ring is slidably fitted in the cylinder in the axial direction, and the opening of the outer end is opened at the axial outer end of the outer ring. A disc-shaped preload member that closes the cylinder is disposed, and hydraulic oil is supplied to a pressurization chamber surrounded by the cylinder inner surface and the preload member by a hydraulic pump. Further, a compression coil spring that biases the preload member inward in the axial direction is provided in the pressurizing chamber.

In this configuration, preload is applied to the preload member by the hydraulic pressure and the compression coil spring, and when the housing changes in size more greatly than the rotation shaft and the outer ring due to temperature rise, the outer ring is moved via the preload member by the action of the compression coil spring and the hydraulic pressure. It is possible to eliminate the shortage of preload by moving inward in the axial direction and suppressing changes in the axial gap and radial gap of the tapered roller bearing.
JP 2006-153090 A

  However, according to the technique of Patent Document 1, it is necessary to always supply hydraulic oil from the hydraulic pump to the pressurizing chamber in order to maintain the hydraulic pressure in the pressurizing chamber at a constant pressure, which means that energy consumption is large. There was a problem. In particular, when the mechanism for eliminating the preload shortage is employed in an automatic transmission, it is conceivable to supply a part of the hydraulic oil used for hydraulic control of the transmission to the pressurizing chamber. Since it is necessary to increase the discharge amount of the hydraulic pump by the amount of hydraulic oil supplied to the pressure chamber, there is a problem that extra energy is required.

  The present invention has been made in view of such problems, and provides a rolling bearing device capable of saving energy when applying a preload to a rolling bearing using fluid pressure such as hydraulic pressure. Objective.

  A rolling bearing device according to the present invention has a rolling element and a raceway surface on the inner periphery that receives the rolling element and a radial load from the rolling element and a load directed to one side in the axial direction. An outer ring having a first linear expansion coefficient, a raceway surface on which the rolling element rolls, and an inner ring incorporated in the outer ring via the rolling element in a state where a preload is applied; A housing having a second linear expansion coefficient larger than a linear expansion coefficient of the outer ring, and a second outer expansion surface fitted to the inner peripheral surface of the inner ring; A rotating shaft having a third linear expansion coefficient smaller than the linear expansion coefficient, a pressurizing chamber configured as a space that can be sealed between the end member on the one axial side of the outer ring and the housing; Fluid pressure is applied to the pressurizing chamber to move the outer ring to the other side in the axial direction. A preload holding means for suppressing a decrease in the preload associated with thermal expansion of the housing, wherein the preload holding means is connected to the pressurizing chamber via a fluid supply path. And a check valve that is provided in a fluid supply path between the pressurizing chamber and the pressure source and that allows the fluid to flow into the pressurizing chamber when the fluid pressure is equal to or higher than a first set pressure. A relief valve provided in a discharge passage for discharging the fluid from the pressurization chamber at a second set pressure higher than the first set pressure, and the pressurization chamber being the first set When the pressure is less than the pressure, the fluid is supplied from the pressure source to the pressurizing chamber through the check valve, and when the pressure is higher than the first set pressure and less than the second set pressure, the fluid is supplied. And a fluid supply control unit for stopping the operation.

  According to the rolling bearing device having such a configuration, when the fluid pressure in the fluid supply path is equal to or higher than the first set pressure, the fluid in the fluid supply path can be supplied to the pressurizing chamber through the check valve. When the pressure chamber becomes equal to or lower than a first set pressure, the fluid supply control unit can supply fluid from the pressure source to the pressure chamber through a check valve. In addition, after the temperature has been raised once, when the pressure chamber becomes equal to or higher than the second set pressure due to cooling accompanying the stop of the operation of the rolling bearing device, the fluid can be discharged from the pressure chamber through the relief valve. And when the said pressurization chamber becomes more than the said 3rd setting pressure, the supply of the said fluid can be stopped by the said fluid supply control part. Therefore, without always supplying fluid from the pressure source to the pressurizing chamber, the pressure in the pressurizing chamber can be maintained between the first set pressure and the third set pressure when the temperature is raised. The outer ring can be moved to the other side in the axial direction by the pressure in the pressurizing chamber, and a decrease in the preload due to thermal expansion of the housing can be suppressed. Further, it is possible to prevent the pressure in the pressure chamber from rising excessively during cooling or the like.

  Moreover, it is preferable that the end part member which comprises the said pressurization chamber has block | closed the edge part opening of the said axial direction one side of the said outer ring | wheel. In this case, it is possible to increase the contact area when the fluid urges the outer ring, and it is possible to prevent the occurrence of uneven fluid pressure when the fluid is supplied and to prevent the outer ring from tilting.

  Further, it is preferable that the outer ring and the end member are integrally formed. In this case, since the rigidity of the outer ring can be increased, the roundness of the raceway surface of the outer ring is deteriorated even though the outer ring is fitted to the housing so as to be movable in the axial direction. Can be suppressed. For this reason, it can prevent that a bearing vibrates or a lifetime falls.

  According to the present invention, since the fluid can be supplied from the pressure source only when the fluid supply to the pressurizing chamber is necessary, energy saving can be achieved as compared with the case where the fluid is always supplied from the pressure source. Can do.

  FIG. 1 is a cross-sectional view showing a transmission that constitutes a rolling bearing device 10 according to a first embodiment of the present invention. The transmission includes a case 12, a gear box 13 incorporated in the case 12, and an input shaft 14 and an output shaft (rotary shaft) 15 provided in parallel to each other with the gear box 13 being passed therethrough. ing. The input shaft 14 and the output shaft 15 are rotated in conjunction with a transmission gear 16 in the gear box 13.

  The transmission gear 16 is, for example, a manual type, and the input shaft 14 is provided with a plurality of input gears 18 having different numbers of teeth, and the output shaft 15 is provided with output gears 19 having different numbers of teeth. Shifting is possible by switching the combination of the meshing of the gear 18 on the input shaft 14 and the gear 19 on the output shaft 15 according to the speed ratio or the distinction between forward and reverse. As the input gear 18 and the output gear 19, a spur gear or a helical gear is used. The transmission gear 16 may be an automatic type using a planetary gear mechanism or the like.

  Both ends of the input shaft 14 are rotatably supported by cylindrical roller bearings 21 and ball bearings 22 fixed inside the case 12. Both ends of the output shaft 15 are supported by a first tapered roller bearing 11 on one axial side (left side) and a second tapered roller bearing 23 on the other axial side (right side). The first tapered roller bearing 11 is fitted into a first housing 25 integral with the case 12, and the second tapered roller bearing 23 is fitted and fixed to a second housing 26 integral with the case 12. The first tapered roller bearing 11 is preloaded by the preload holding means 30 in the axially inward (rightward) direction. The preload holding means 30 will be described in detail later.

  FIG. 2 is an enlarged cross-sectional view showing the main part of the present invention. As shown in the figure, the first tapered roller bearing 11 includes an outer ring 32, an inner ring 33, and a plurality of tapered rollers (rolling elements) 34 disposed between the outer ring 32 and the inner ring 33. An outer peripheral surface of the outer ring 32 is fitted to an inner peripheral surface of the first housing 25, and an inner peripheral raceway surface 32 a is formed on the inner peripheral surface of the outer ring 32. On the outer peripheral surface of the inner ring 33, an outer peripheral raceway surface 33 a on which the tapered rollers 34 roll obliquely is formed, and the output shaft 15 is fitted on the inner peripheral surface of the inner ring 33. The contact angle between the inner ring 33 and the tapered roller 34 and the contact angle between the tapered roller 34 and the outer ring 32 are set so as to increase in diameter from the axially inner side (right side) toward the axially outer side (left side). Here, the contact angle conforms to the nominal contact angle defined in JIS B0104-1991.

The outer ring 32 of the first tapered roller bearing 11 is provided with a closing member (end member) 36. The closing member 36 is formed integrally with the outer ring 32 so as to close the opening of the outer ring 32 at the axially outer end (left end) of the outer ring 32. Therefore, the outer ring 32 has a solid structure in the outer end portion in the axial direction, and has a shape in which only the inner end portion in the axial direction is opened.
Further, the outer peripheral side of the outer ring 32 is reduced in diameter in the axial outer end portion, and a seal member 38 is fitted to the outer peripheral surface of the reduced diameter portion 32c.

  The seal member 38 is a pressure-resistant seal made of reinforced rubber, and has a cylindrical portion 38a fitted to the outer peripheral surface of the reduced diameter portion 32c, and a lip portion 38b protruding radially outward from the cylindrical portion 38a. . The rubber material used for the seal member 38 is preferably a rubber capable of achieving both mechanical strength and oil resistance, such as nitrile rubber (particularly hydrogenated nitrile rubber), acrylic rubber, silicon rubber, and fluorine rubber.

  The lip portion 38b has an annular portion 38d extending radially outward from the axially inner end portion (right end portion) of the cylindrical portion 38a, and an axially outward portion from the radially outer end portion of the annular portion 38d ( And a contact portion 38c extending to the left. The outer peripheral surface of the contact portion 38c has a mountain shape that is tapered outward in the radial direction. The lip portion 38b is in pressure contact with the inner peripheral surface of the first housing 25 by elastically deforming radially inward. The shape of the lip portion 38b is not limited to this, and may be a shape that extends obliquely substantially linearly from the cylindrical portion 38a outward in the radial direction and outward in the axial direction.

The outer ring 32 of the first tapered roller bearing 11 has a first linear expansion coefficient. In contrast, the first housing 25 has a second linear expansion coefficient larger than the first linear expansion coefficient. The output shaft 15 has a third linear expansion coefficient smaller than the second linear expansion coefficient.
For example, in the first tapered roller bearing 11, the outer ring 32, the inner ring 33, and the rolling element 34 are all formed of steel (for example, bearing steel, case hardened steel, carburized steel), and the first housing 25 is a light metal. The output shaft 15 is formed of steel (for example, carbon steel for machine structure). . Preferably, the first housing 25 is made of Al or an Al alloy from the viewpoints of workability and corrosion resistance. As the Al alloy, for example, an Al alloy for die casting is used. In the present embodiment, the case 12 (FIG. 1) is also made of an Al alloy, and the first housing 25 is integrated with the inner surface of the case 12.

  The linear expansion coefficient (second linear expansion coefficient) of Al that is the main component of the first housing 25 is 23 to 24 ppm / ° C., and the linear expansion coefficient of Fe that is the main component of the output shaft 15 and the first tapered roller bearing 11 ( The first and third linear expansion coefficients are about 12 to 13 ppm / ° C. In general, the bearing use environment temperature in the automobile transmission is in the range of −40 ° C. to 150 ° C. (normally reached temperature excluding cold regions and high-speed continuous operation is 50 ° C. to 80 ° C.).

The preload holding means 30 applies axially inward preload to the first tapered roller bearing 11, and is connected to the cylinder 43 with a bottomed cylindrical cylinder 43 provided in the first housing 25. The hydraulic oil supply mechanism A for supplying the hydraulic oil into the cylinder 43 and the hydraulic oil discharge mechanism B for discharging the hydraulic oil in the cylinder 43 are provided.
A large diameter portion 32b of the outer ring 32 is fitted to the inner periphery of the cylinder 43 so as to be slidable in the axial direction, and a space formed between the inner surface of the cylinder 43 and the closing member 36 of the outer ring 32 is a seal member. The pressurizing chamber 45 is a space that can be sealed by the pressure chamber 38. A solid lubricant is coated on the outer peripheral surface of the outer ring 32 in order to make sliding smoothly. As the solid lubricant, for example, a fluororesin such as polytetrafluoroethylene, molybdenum disulfide, graphite or molybdenum, or a dispersion of these in a resin can be used.

The hydraulic oil supply mechanism A includes a fluid supply path 48, a hydraulic pump 49 serving as a pressure source connected to the pressurizing chamber 45 through the fluid supply path 48, and the hydraulic pump 49 and the pressurizing chamber 45. A check valve 44 provided in the fluid supply path 48 and a fluid supply control unit 60 for controlling supply and stop of supply of the fluid by the hydraulic pump 49.
In this embodiment, the check valve 44 is disposed on the bottom wall 43a of the cylinder 43, and a first check ball 44b that can move along an internal space (first internal space) 44d along the flow path. And a first urging member 44c that urges the first check ball 44b axially outward with a first set pressure.

  The first urging member 44c is composed of a compression coil spring, and the first set pressure is set according to the specifications such as the volume and shape of the pressurizing chamber 45, the type and size of the bearing. The first check ball 44b is pushed outward in the axial direction by the first urging member 44c to close the left end portion (the hole of the fluid supply path 48) of the first internal space 44d. When the hydraulic oil is supplied from the hydraulic pump 49 at a pressure equal to or higher than the first set pressure, the first check ball 44b moves inward in the axial direction against the urging force of the first urging member 44c. The first internal space 44d and the fluid supply path 48 on the hydraulic pump 49 side communicate with each other, and hydraulic oil flows into the pressurizing chamber 45. In other words, the first urging member 44c moves the first check ball 44b inward in the axial direction by losing the hydraulic pressure of the hydraulic oil loaded from the hydraulic pump 49 to the check valve 44 from the first set pressure. The maximum hydraulic pressure on the pressurizing chamber side that can be generated, substantially the fluid pressure of the hydraulic oil supplied from the hydraulic pump 49, and the minimum differential pressure a required when the check valve 44 is communicated Based on the difference.

  In this way, when hydraulic oil is supplied to the pressurizing chamber 45 by the hydraulic pump 49 via the fluid supply path 48 and the check valve 44, the outer ring 32 slightly moves inward in the axial direction and preload is applied. The outer ring 32 receives a component force from the inclined rolling surface of the tapered roller 34 and is displaced in the axial direction and the radial direction, and the preload in the radial direction is such that the outer peripheral surface of the outer ring 32 is pressed against the inner peripheral surface of the cylinder 43. Supported by.

  The hydraulic oil discharge mechanism B includes a relief valve 50 disposed on the bottom wall 43 a of the cylinder 43, and a discharge passage 51 that connects the pressurizing chamber 45 and the oil tank 52 via the relief valve 50. . The relief valve 50 has a second check ball 50b that can move in the internal space (second internal space) 50d, and urges the second check ball 50b inward in the axial direction with a second set pressure. And a second urging member 50c. That is, the relief valve 50 has the same basic structure as the check valve 44 and is disposed in a state in which the hydraulic oil discharge direction and the inflow direction are reversed from side to side.

The second set pressure is set to a pressure higher than the first set pressure. The second check ball 50b is pressed by the second urging member 50c and is pushed inward in the axial direction to close the right end portion (the hole of the discharge passage 51) of the second inner space 50d. Further, when the pressure in the pressurizing chamber 45 becomes equal to or higher than the second set pressure, the second check ball 50b moves outward in the axial direction, and the pressurizing chamber 45 and the second internal space 50d communicate with each other. The hydraulic oil in the pressurizing chamber 45 is collected in the oil tank 52 through the discharge passage 51. In other words, the second set pressure loses the pressure of the hydraulic oil loaded from the pressurizing chamber 45 to the relief valve 50, and the second urging member 50c moves the second check ball 50b outward in the axial direction. This is the minimum pressure on the pressurizing chamber 45 side that can be made, and substantially makes the fluid pressure on the discharge side (in this embodiment, the pressure in the oil tank 52 and atmospheric pressure) communicate with the relief valve 50. Sometimes based on the sum of the minimum differential pressure b required. When the hydraulic oil is the same as the lubricating oil for the transmission, the hydraulic oil may be discharged into the transmission by the hydraulic oil discharge mechanism B. In this case, naturally, the second set pressure is based on the sum of the pressure in the transmission and the minimum differential pressure b required when the relief valve 50 is communicated.
Since the second set pressure is set to a pressure equal to or higher than the first set pressure, the pressure in the pressurizing chamber 45 is set to the first set pressure by the functions of the check valve 44 and the relief valve 50 described above. It is maintained between the second set pressure.

  The fluid supply control unit 60 includes a sensor 61 that detects the hydraulic pressure of the pressurizing chamber 45, and can drive or stop the hydraulic pump 49 based on a detection signal from the sensor 61. That is, when the sensor 61 detects that the hydraulic pressure in the pressurizing chamber 45 has become less than the first set pressure, the fluid supply control unit 60 drives the hydraulic pump 49 and passes through the check valve 44 to pressurize the chamber 45. When the sensor 61 detects that the hydraulic pressure in the pressurizing chamber 45 is equal to or higher than the third set pressure that is equal to or higher than the first set pressure and lower than the second set pressure, the hydraulic pump 49 is supplied. Is stopped and the supply of hydraulic oil to the pressurizing chamber 45 is stopped. In this case, the hydraulic pressure of the hydraulic oil loaded from the hydraulic pump 49 to the check valve 44 is equal to or greater than the sum of the third set pressure and the minimum differential pressure a required for communicating the check valve 44. Good. As a result, the hydraulic pressure of the hydraulic oil in the pressurizing chamber 45 becomes substantially equal to or higher than the third set pressure. If the pressure of the hydraulic oil in the pressurizing chamber 45 is larger than the second set pressure, the hydraulic oil is discharged from the relief valve 50, and the sensor 61 sets the hydraulic pressure in the pressurizing chamber 45 below the second set pressure. Since it is detected that the pressure exceeds the set pressure of 3, the drive of the hydraulic pump 49 is stopped. For this reason, it is preferable that the maximum value of the pressure of the hydraulic oil loaded on the check valve 44 of the hydraulic pump 49 is smaller than the second set pressure in order to eliminate excessive driving of the hydraulic pump 49. Further, the third set pressure may be the same value as the first set pressure.

  In the rolling bearing device 10 having the above-described configuration, when the temperature of the transmission in which the rolling bearing device 10 is incorporated is kept relatively constant at a relatively low temperature, the first housing 25, the outer ring 32, and the output shaft 15 are thermally expanded. The difference in dimensional change does not occur so much and the preload is kept constant. At this time, hydraulic oil is supplied to the pressurizing chamber 45, and the hydraulic pressure is maintained between the first set pressure and the second set pressure, and the hydraulic pump 49 is connected to the fluid supply control unit 60. The drive is stopped by.

When the transmission rises in temperature, the linear expansion coefficients of the transmission, the first housing 25 and the second housing 26 are larger than the linear expansion coefficient of the output shaft 15, so that the transmission, the first housing 25 and the second housing 26 are axial. The outer ring 32 tends to be separated from the tapered roller 34.
Further, since the first housing 25 has a larger linear expansion coefficient than the first tapered roller bearing 11, the inner peripheral surface of the first housing 25 (cylinder 43) expands, and tries to separate from the outer peripheral surface of the outer ring 32. To do. That is, the support position of the outer peripheral surface of the outer ring 32 by the inner peripheral surface of the first housing 25 changes radially outward, and the reaction force to the outer ring 32 by the first housing 25 decreases.

  Then, the outer ring 32 is pressed inward in the axial direction by the hydraulic pressure in the pressurizing chamber 45, and moves to a position where the preload applied to the outer ring 32 and the reaction force from the first housing 25 are balanced. As a result, even if the support position of the outer peripheral surface of the outer ring 32 moves due to a temperature rise, the preload on the outer ring 32 is kept substantially constant. When the hydraulic pressure in the pressurizing chamber 45 drops below the first set pressure as the outer ring 32 moves, the fluid supply control unit 60 drives the hydraulic pump 49 to supply hydraulic oil into the pressurizing chamber 45. When the hydraulic pressure in the pressurizing chamber 45 reaches the third set pressure, the hydraulic pump 49 is stopped to stop supplying hydraulic oil.

  As described above, the rolling bearing device 10 drives the hydraulic pump 49 only when the pressure in the pressurizing chamber 45 is reduced, and the pressure in the pressurizing chamber 45 is changed between the first set pressure and the third set pressure. Since the pressure is maintained in between, the energy required for driving the hydraulic pump 49 can be reduced as compared with the case where the hydraulic pump 49 is always driven to maintain the pressure in the pressurizing chamber 45.

  Further, as shown in FIG. 2, when the inner peripheral surface of the first housing 25 is expanded in diameter and separated from the outer peripheral surface of the outer ring 32, the lip portion 38 b of the seal member 38 provided on the outer ring 32 is formed inside the first housing 25. The elastic recovery is performed following the peripheral surface, and the pressure contact (adhesion) state is maintained. Therefore, the hydraulic oil hardly leaks from the gap between the inner peripheral surface of the first housing 25 and the outer peripheral surface of the outer ring 32, and the preload can be maintained.

When the temperature of the transmission decreases as the transmission stops, the first housing 25 is thermally contracted in the axial direction and the radial direction, and the pressurizing chamber 45 is contracted. As a result, the hydraulic oil in the pressurizing chamber 45 is pressurized, and an excessive preload is applied to the first tapered roller bearing 11. However, when the inside of the pressurizing chamber 45 becomes equal to or higher than the second set pressure, the relief valve 50 of the hydraulic oil discharge mechanism B opens and communicates with the discharge passage 51, and the hydraulic oil is discharged from the pressurization chamber 45. The pressure in the pressurizing chamber 45 is maintained appropriately. In this case, the check valve 44 prevents the hydraulic oil from flowing back to the hydraulic pump 49.
As described above, even when the temperature of the rolling bearing device 10 is lowered, the pressure of the pressurizing chamber 45 is maintained at the second set pressure by the action of the relief valve 50. It is possible to prevent an excessive increase in pressure.

  The first set pressure is a pressure necessary for applying a substantially minimum preload within a predetermined preload range to be applied to the first tapered roller bearing 11, and the second set pressure is the first tapered roller bearing 11. This is a pressure necessary for applying a substantially maximum preload within a predetermined preload range to be applied.

Further, when an impact load or the like is applied to the output shaft 15 in the direction opposite to the preload application direction (axially outward) due to transmission speed change or clutch (not shown) connection / disconnection, the inner ring 33 and the tapered roller 34 are applied. The outer ring 32 moves in the axial direction against the hydraulic pressure in the pressurizing chamber 45 through the shaft, and an excessive preload may be applied to the first tapered roller bearing 11. When B functions and discharges the hydraulic oil in the pressurizing chamber 45, it is possible to prevent the first tapered roller bearing 11 from being given an excessive preload. In this case, the hydraulic pressure in the pressurizing chamber 45 rises momentarily, but the hydraulic oil is prevented from flowing back to the hydraulic pump 49 by the action of the check valve 44.
Further, even if the pressure in the pressurizing chamber 45 is instantaneously increased due to the impact load, the outer ring 32 is provided with the seal member 38 made of a pressure-resistant seal. There is no possibility that the hydraulic oil leaks from the gap between the outer ring 32 and the outer peripheral surface.

  On the other hand, when the rolling bearing device 10 is applied to an automatic transmission and configured to supply a part of hydraulic oil used for hydraulic control of the transmission to the pressurizing chamber 45, the operation to supply the pressurizing chamber 45 is performed. Although it is necessary to increase the discharge amount of the hydraulic pump for transmission by the amount of oil, it is not necessary to supply hydraulic oil to the pressurizing chamber 45 once the hydraulic pressure in the pressurizing chamber 45 has exceeded the third set pressure. Therefore, by restricting the supply by a control valve or the like, the amount of hydraulic oil supplied by the hydraulic pump can be reduced. For this reason, the energy required for driving the hydraulic pump can be reduced.

  The closing member 36 can be configured separately from the outer ring 32. However, since the rigidity of the outer ring 32 is increased by integrally forming the outer ring 32 and the closing member 36 as in this embodiment, the inner peripheral surface of the first housing 25 is increased with the temperature rise of the transmission. Even when a gap is generated between the outer ring 32 and the outer peripheral surface, the deterioration of the roundness of the raceway can be suppressed and the bearing performance can be maintained. Further, when the outer ring 32 and the closing member 36 are separate, the outer ring 32 and the closing member 36 are easily inclined individually when the inner peripheral surface of the first housing 25 is expanded, and the outer ring 32 and the closing member 36 are easily inclined. However, by forming the outer ring 32 and the closing member 36 integrally, such inconvenience does not occur.

  In the above embodiment, the sensor 61 is disposed in the pressurizing chamber 45 to detect the hydraulic pressure of the pressurizing chamber 45. However, the pressurizing chamber 45 is more than the check valve 44, more specifically, the first check ball 44b. It may be disposed in the fluid supply path 48 on the side, or may be disposed in the discharge path 51 on the pressurizing chamber 45 side with respect to the relief valve 50, more specifically, the second check ball 50b. By disposing the sensor 61 at these positions, the hydraulic pressure in the pressurizing chamber 45 can be detected.

  Moreover, in the said Example, although the non-return valve 44 was comprised by the 1st check ball | bowl 44b, the 1st biasing member 44c, and the 1st internal space 44d, you may comprise by an electromagnetic valve. In this case, when the sensor 61 detects that the pressure is less than the first set pressure, the hydraulic pressure in the pressurizing chamber 45 can be maintained at the first set pressure or higher by driving the hydraulic pump 49 and opening the electromagnetic valve. . Furthermore, if the solenoid valve is closed when at least the first set pressure or more, preferably the third set pressure or more is detected, an impact load or the like is applied and an excessive preload is applied to the first tapered roller bearing 11. When the hydraulic pressure in the pressurizing chamber 45 increases momentarily, the hydraulic oil can be prevented from flowing back to the hydraulic pump 49.

The present invention is not limited to the embodiment described above, and can be appropriately changed in design. For example, although the rolling bearing device used in the transmission is shown in the above embodiment, the present invention can be applied to other devices such as a gear unit for a drive distribution shaft of a four-wheel drive vehicle.
Further, the rolling bearing is not limited to the tapered roller bearing, but may be another rolling bearing using a preload such as an angular ball bearing or a deep groove ball bearing.

It is sectional drawing which shows the transmission which comprised the rolling bearing apparatus which concerns on embodiment of this invention. It is an expanded sectional view of the principal part of a rolling bearing device. It is an expanded sectional view of the principal part of the conventional rolling bearing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rolling bearing apparatus 11 1st tapered roller bearing (rolling bearing)
15 Output shaft (rotary shaft)
25 First housing (housing)
30 Preload holding means 32 Outer ring 32a Inner raceway surface 33 Inner ring 33a Outer raceway surface 34 Tapered roller (rolling element)
36 Closure member (end member)
44 Check valve 45 Pressurizing chamber 48 Fluid supply path 49 Hydraulic pump (pressure source)
50 Relief valve 51 Drain path A Hydraulic oil supply mechanism B Hydraulic oil discharge mechanism

Claims (3)

Rolling elements,
An outer ring having a raceway surface on the inner periphery that receives a radial load from the rolling element and a load directed to one side in the axial direction, and has a first linear expansion coefficient;
An inner ring that has a raceway surface on which the rolling element rolls on the outer periphery and is incorporated in an outer ring via the rolling element in a state in which a preload is applied;
A housing having a second linear expansion coefficient larger than a linear expansion coefficient of the outer ring, and an outer peripheral surface of the outer ring is fitted so as to be movable in the axial direction;
A rotating shaft fitted to the inner peripheral surface of the inner ring and having a third linear expansion coefficient smaller than the second linear expansion coefficient;
A pressurizing chamber configured as a sealable space between the end member on one axial side of the outer ring and the housing;
And a preload holding means for suppressing a decrease in the preload accompanying thermal expansion of the housing by applying fluid pressure to the pressurizing chamber to move the outer ring to the other side in the axial direction. And
The preload holding means is
A pressure source connected to the pressurizing chamber via a fluid supply path;
A check valve provided in a fluid supply path between the pressurizing chamber and a pressure source and allowing fluid to flow into the pressurizing chamber when the fluid pressure is equal to or higher than a first set pressure;
A relief valve provided in a discharge path for discharging the fluid from the pressurizing chamber at a pressure equal to or higher than a second set pressure higher than the first set pressure;
When the pressurizing chamber is less than the first set pressure, a fluid is supplied from the pressure source to the pressurizing chamber through the check valve, and the third set pressure is not less than the first set pressure and less than the second set pressure. A rolling bearing device comprising: a fluid supply control unit that stops supply of the fluid when the pressure exceeds a set pressure.   The rolling bearing device according to claim 1, wherein an end member constituting the pressurizing chamber closes an end opening on the one axial side of the outer ring.   The rolling bearing device according to claim 1, wherein the outer ring and the end member are integrally formed.

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