JP4935340B2 - Rolling bearing device - Google Patents

Description

  The present invention relates to a rolling bearing device incorporating a rolling bearing used with a preload 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, a gear-type drive transmission unit for an automobile such as a transmission unit employs a tapered roller bearing at its main point (for example, a final reduction gear portion in the transmission unit), as shown in FIG. The rotary shaft 115 is press-fitted into the inner ring 133 of the tapered roller bearing 111, the outer ring 132 is press-fitted into the bearing housing 125 of the transmission case, and then a preload is applied toward one axial side (arrow a). Yes. When the preload is applied, 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 its right end surface 132c and outer peripheral surface 132b are the inner end surface of the bearing housing 125. The preload is supported by being pressed against 125c and the inner peripheral surface 125a.

On the other hand, in recent years, as a part of weight reduction, a transmission case (bearing housing) is made of a light metal such as an Al alloy. Al has the highest linear expansion coefficient among structural materials (approximately 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 (about 12 ppm / ° C. at room temperature) of steel (Fe-based material).

When the rotating shaft and the bearing 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 bearing housing is made of a light metal, the bearing 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 bearing housing 125 and the rotating shaft 115 expand, but due to the difference in dimensional change due to the expansion, the inner peripheral raceway surface 132a of the outer ring 132. Is separated 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 bearing housing, and an outer ring is fitted in the cylinder so as to be slidable in the axial direction, and a disk-shaped preload that abuts against the outer end of the outer ring in the axial direction. A member is provided, and oil is supplied by a hydraulic pump to a hydraulic chamber surrounded by the cylinder inner surface and the preload member. Further, a compression coil spring that urges the preload member inward in the axial direction is provided in the hydraulic chamber.

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

  However, since the preloading member of Patent Document 1 is formed in a disk shape and is only in contact with the outer surface in the axial direction of the outer ring, the outer ring and the preloading member when the inner peripheral surface of the bearing housing is expanded by thermal expansion. May incline individually, and the relative positions of the two may shift. When the outer ring and the preload member rub against each other due to this positional shift, wear occurs, resulting in a decrease in durability, or wear powder causing a rolling contact portion between the rolling element and the inner ring and the outer ring.

  In addition, if an axial impact load is applied from the rotating shaft to the tapered roller bearing, the pressure in the hydraulic chamber may increase excessively, causing oil to leak between the bearing housing, the preload member, and the outer ring. There is a problem that oil consumption increases.

  The present invention has been made in view of such circumstances, and is a rolling bearing device capable of preventing the occurrence of wear due to the relative displacement between a preload member on which a liquid pressure such as hydraulic pressure acts and an outer ring. The purpose is to provide.

A rolling bearing device according to the present invention includes a rolling element, an inner ring having a raceway surface on which the rolling element rolls, an outer ring, a radial load from the rolling element and an axial direction one of the rolling element. A rolling bearing provided with an outer ring having a raceway surface on the inner periphery for receiving a load directed to the side and having a first linear expansion coefficient;
A preload member having a second linear expansion coefficient, comprising: a cylindrical portion into which an outer peripheral surface of the outer ring is fitted; and a closing portion that closes an inner peripheral side opening on the one axial side of the outer ring;
A bearing housing having an inner peripheral surface with which the cylindrical portion of the preload member is fitted, and having a third linear expansion coefficient larger than the first and second linear expansion coefficients;
A rotating shaft that fits to the inner peripheral surface of the inner ring and has a fourth linear expansion coefficient smaller than the third linear expansion coefficient;
A preload application mechanism that applies a preload directed to the other side in the axial direction by the liquid pressure ,
The preload member includes a flange portion that faces the end surface on the other axial side of the bearing housing and is capable of contacting the end surface .

  According to this, since the outer ring is fitted to the cylindrical portion of the preload member to which the preload is applied by the liquid pressure, the inner peripheral surface of the bearing housing expands due to the temperature rise, and between the outer peripheral surface of the cylindrical portion. Even if the gap is generated, the outer ring and the preload member are not individually inclined, and the relative displacement between the outer ring and the preload member is less likely to be caused by the displacement.

Since the preload member includes a flange portion that faces the end surface on the other axial side of the bearing housing and is capable of contacting the end surface, an impact load or the like directed from the rotary shaft to the one axial side is a rolling bearing. When the preload member is applied, the flange portion abuts against the end face of the bearing housing, thereby receiving the impact load and preventing the liquid pressure acting on the preload member from excessively rising. Therefore, it is possible to prevent liquid leakage due to an increase in liquid pressure and reduce the amount of liquid consumption.

  According to the present invention, it is possible to prevent the occurrence of wear due to the relative displacement between the preload member on which a liquid pressure such as hydraulic pressure acts and the outer ring.

  FIG. 1 is a side cross-sectional view showing a rolling bearing device according to a first embodiment of the present invention. This rolling bearing device is configured by incorporating a rolling bearing 11 in the transmission 10. The transmission 10 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 with each other so as to penetrate the gear box 13. Yes. 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 meshing of the gear 18 on the input shaft 14 and the gear 19 on the output shaft 15 in accordance with the speed ratio or forward / reverse distinction. 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 tapered roller bearings 11 and 23, respectively. The tapered roller bearing 11 on one side (left side) in the axial direction is fitted into a bearing housing 25 integral with the case 12, and the tapered roller bearing 23 on the other side (right side) in the axial direction is fitted into a bearing housing 26 integral with the case 12. The stopper is fixed. The left tapered roller bearing 11 is given a preload from the preload application mechanism 30 in the axially inward direction (right direction). The preload applying mechanism 30 will be described in detail later.

FIG. 2 is an enlarged cross-sectional view showing the main part of the present invention. The left 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. The outer peripheral surface of the outer ring 32 is fitted to the inner peripheral surface of the preload member 36, 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.
These configurations also apply to the right tapered roller bearing 23 (FIG. 1) except that the inner side in the axial direction is the left side, the outer side in the axial direction is the right side, and the outer ring is directly fitted to the bearing housing 26. Is the same.

  The preload member 36 includes a cylindrical portion 36b into which the outer ring 32 of the left tapered roller bearing 11 is fitted, a closed portion 36a provided at an axially outer end (left end portion) of the cylindrical portion 36b, and a cylindrical portion 36b. A flange portion 36c provided at the inner end (right end) in the axial direction, and the cylindrical portion 36b, the closing portion 36a and the flange portion 36c are integrally formed by, for example, pressing a metal plate material. ing.

  The cylindrical portion 36b extends in the direction of the axis X of the rotary shaft 15, and is fitted to the inner peripheral surface of the bearing housing 25 so as to be slidable in the direction of the axis X. The blocking portion 36a is formed in a disk shape and is disposed so as to block the entire inner peripheral opening at the outer end portion (left end portion) in the axial direction of the outer ring 32. The flange portion 36 c is formed in an annular shape, protrudes radially outward from the cylindrical portion 36 b, and faces the end surface 25 a on the inner side in the axial direction of the bearing housing 25. The preload member 36 is restricted from moving outward in the axial direction (rightward) by the flange portion 36c coming into contact with the end face 25a of the bearing housing 25.

  A plurality (two in the illustrated example) of circumferential grooves 52 are formed on the inner peripheral surface of the bearing housing 25 at intervals in the axial direction. Reinforced rubber O-rings 53 are fitted in the respective circumferential grooves 52, and the O-rings 53 are pressed against the outer peripheral surface of the cylindrical portion 36b of the preload member 36 and elastically deformed. The material of the rubber used for the O-ring 53 is a rubber capable of achieving both mechanical strength and oil resistance in consideration of contact with the oil of the preload imparting mechanism 30, such as nitrile rubber (particularly hydrogenated nitrile rubber), Acrylic rubber, silicon rubber, fluorine rubber and the like are suitable.

The outer ring 32 of the tapered roller bearing 11 has a first linear expansion coefficient, and the preload member 36 has a second linear expansion coefficient. On the other hand, the bearing housing 25 has a third linear expansion coefficient larger than the first and second linear expansion coefficients. The output shaft 15 has a fourth linear expansion coefficient that is smaller than the third linear expansion coefficient.
For example, in the tapered roller bearing 11, the outer ring 32, the inner ring 33, and the rolling element 34 are all made of steel (for example, bearing steel, case-hardened steel, carburized steel), and the preload member 36 is also made of steel. It is formed. The bearing housing 25 is made of, for example, light metal (made of metal containing either Al or Mg as a main component (content of 50% by mass or more)), and the output shaft 15 is made of steel (for example, a mechanical structure). For low alloy steel).

Preferably, the bearing housing 25 is made of Al or an Al alloy from the viewpoint 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 bearing housing 25 is integrated with the inner surface of the case 12.
The linear expansion coefficient (second linear expansion coefficient) of Al that is a main component of the bearing housing 25 is 23 to 24 ppm / ° C., and the Fe wire that is the main component of the output shaft 15, the tapered roller bearing 11, and the preload member 36. The expansion coefficient (first and third linear expansion coefficients) is 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.).

  As shown in FIG. 1, the preload applying mechanism 30 applies a preload in the axial direction to the tapered roller bearing 11, and a bottomed cylindrical cylinder 43 provided in the bearing housing 25, and this cylinder 43, and pressure supply means 44 for supplying hydraulic pressure (liquid pressure) into the cylinder 43. A preload member 36 is fitted in 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 closed portion 36a of the preload member 36 is a hydraulic chamber (liquid pressure chamber). 45.

  The outer peripheral surface of the cylindrical portion 36b of the preload member 36 is coated with a solid lubricant for smooth sliding. As the solid lubricant, for example, a fluororesin such as polytetrafluoroethylene, molybdenum disulfide, graphite, molybdenum, or a dispersion of these in a resin can be used. The pressure supply means 44 includes an oil passage (flow passage) 47 connected to the inside of the hydraulic chamber 45 through a through hole 46 formed in the bottom wall of the cylinder 43, and a hydraulic pump 48 for flowing oil through the oil passage 47. I have.

  When oil is supplied to the hydraulic chamber 45 through the oil passage 47 and the through hole 46 by the operation of the hydraulic pump 48, the outer ring 32 is axially inward (rightward) via the preload member 36 as shown in FIG. 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 outer circumferential surface of the outer ring 32 is pressed against the inner circumferential surface of the cylindrical portion 36b. The outer peripheral surface of the cylindrical portion 36b is supported by being pressed against the inner peripheral surface of the bearing housing 25. The preload applied to the outer ring 32 can be adjusted according to the pumping pressure of the hydraulic pump 48.

  As shown in FIG. 1, the preload applying mechanism 30 also includes a pressure discharge means 50. The pressure discharge means 50 is for discharging the oil in the hydraulic chamber 45 and releasing the preload when an excessive preload is generated in the tapered roller bearing 11 due to an increase in the pressure in the hydraulic chamber 45. The discharged oil is configured to flow into a hydraulic tank or a discharge container for the hydraulic pump. In the case where the oil is the same as the lubricating oil of the transmission 10, the oil may be discharged into the transmission 10 by the pressure discharging means 50.

  As the pressure discharge means 50, for example, an on-off valve such as an electromagnetic valve or a relief valve, or a means for holding a differential pressure such as an orifice or a needle is used. In the case of a solenoid valve, a pressure sensor for monitoring the internal pressure of the pressure supply means 44 (the internal pressure of the hydraulic chamber 45 and the through hole 46, the pressure of the hydraulic pump 48) is provided, and when the internal pressure rises excessively, the pressure sensor By opening the solenoid valve provided in the oil passage 47 based on the detected value, the oil is discharged and the internal pressure is made appropriate. In the case of a relief valve, the pressure is set in advance so that it opens and discharges oil when the internal pressure of the hydraulic chamber 45 exceeds a certain pressure. In the case of an orifice or a needle, it is set so that an appropriate internal pressure can be obtained.

  When a check valve is provided in the oil passage 47 or the through hole 46 to prevent the backflow of oil from the hydraulic chamber 45 to the hydraulic pump 48, another oil passage is connected to the hydraulic chamber 45 and the above-mentioned An electromagnetic valve or a relief valve may be provided, and when the pressure in the hydraulic chamber 45 exceeds a predetermined pressure, the electromagnetic valve or the relief valve may be opened to discharge oil from the other oil passage.

Hereinafter, the operation of the rolling bearing device according to the present embodiment will be described.
As described above, axial pressure is applied to the outer ring 32 of the tapered roller bearing 11 through the preload member 36 by supplying hydraulic pressure from the hydraulic pump 48 to the hydraulic chamber 45. Since the preload member 36 receives the hydraulic pressure from the pressure supply means 44 by the large-area closed portion 36a, a large force can be applied to the outer ring 32 even with a small hydraulic pressure. Accordingly, a hydraulic pump having a small capacity can be used, and the preload applying mechanism 30 can be reduced in size and cost.

When the temperature of the transmission 10 is kept relatively constant at a relatively low temperature, the difference in dimensional change due to thermal expansion of the bearing housing 25, the preload member 36, the outer ring 32, and the output shaft 15 does not occur so much, and the preload is also kept constant. It is.
When the temperature of the transmission 10 rises, the transmission 10 and the bearing housings 25 and 26 have a larger linear expansion coefficient than the output shaft 15, so that the transmission 10 and the bearing housings 25 and 26 expand greatly in the axial direction, and the outer ring 32 has a conical shape. Trying to move away from the roller 34.

  In addition, since the bearing housing 25 has a larger linear expansion coefficient than the tapered roller bearing 11 and the preload member 36, the inner peripheral surface of the bearing housing 25 (cylinder 43) expands and is separated from the outer peripheral surface of the cylindrical portion 36b. And That is, the support position of the outer peripheral surface of the cylindrical portion 36b by the inner peripheral surface of the bearing housing 25 changes radially outward, and the reaction force of the bearing housing 25 on the preload member 36 decreases.

  At this time, the preload member 36 and the outer ring 32 are pressed inward (rightward) in the axial direction by the hydraulic pressure from the hydraulic pump 48, the preload applied to the preload member 36 and the outer ring 32, and the reaction force from the bearing housing 25. Move to a position where and balance. As a result, even if the support position of the outer peripheral surface of the cylindrical portion 36b is moved by the inner peripheral surface of the bearing housing 25 due to the temperature rise, the preload on the preload member 36 and the outer ring 32 is kept substantially constant.

  Further, as shown in FIG. 2, when the inner peripheral surface of the bearing housing 25 is enlarged in diameter and separated from the outer peripheral surface of the cylindrical portion 36b, the O-ring 53 provided in the bearing housing 25 is elastically restored and the outer periphery of the cylindrical portion 36b is recovered. Maintain the state of pressure contact (contact) with the surface. Since the O-ring 53 is made of rubber and has a larger linear expansion coefficient (fourth linear expansion coefficient) than the bearing housing 25, the O-ring 53 expands larger than the bearing housing 25 due to a temperature rise and becomes a cylindrical portion. It adheres more closely to the outer peripheral surface of 36b. Therefore, oil leakage from the gap between the inner peripheral surface of the bearing housing 25 and the outer peripheral surface of the cylindrical portion 36b can be prevented, and the preload can be maintained.

Furthermore, since a plurality of O-rings 53 are provided apart from each other in the axial direction, oil leakage can be prevented more reliably and the operation of the hydraulic pump 48 can be suppressed to save energy. Further, by providing a plurality of O-rings 53 that are spaced apart in the axial direction, it is possible to prevent the preload member 36 from being inclined when the inner peripheral surface of the bearing housing 25 is expanded in diameter.
The outer ring 32 is increased in rigidity by being fitted to the preload member 36, and as the transmission 10 rises in temperature, a gap is formed between the inner peripheral surface of the bearing housing 25 and the outer peripheral surface of the cylindrical portion 36b. Even if it occurs, the deterioration of the roundness of the raceway can be suppressed and the bearing performance can be maintained.

  The preload member 36 includes a cylindrical portion 36b and a closed portion 36a, and the outer ring 32 is fitted to the cylindrical portion 36b. Therefore, when the inner peripheral surface of the bearing housing is expanded, the outer ring 32 and the preload member 36 are Are not individually inclined, and wear is not caused due to the relative displacement between the two members 32 and 36. Further, since the flange portion 36 c is formed in the preload member 36, the inclination of the preload member 36 can be suppressed by the flange portion 36 c coming into contact with the end surface of the bearing housing 25.

When the temperature of the transmission 10 is lowered, the bearing housing 25 is thermally contracted in the axial direction and the radial direction, and the hydraulic chamber 45 is reduced. Thereby, the oil in the hydraulic chamber 45 is pressurized, and an excessive preload acts on the tapered roller bearing 11. In this case, as shown in FIG. 1, the pressure discharge means 50 functions and discharges oil from the hydraulic chamber 45, whereby the pressure in the hydraulic chamber 45 is properly maintained.
Even 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 the transmission 10 shifting or the clutch (not shown) being connected or disconnected, the inner ring 33 and the tapered roller 34 are also applied. The outer ring 32 and the preloading member 36 move axially outward against the hydraulic pressure by the hydraulic pump 48, and an excessive preload acts on the tapered roller bearing 11, but in this case also, the pressure discharge means 50 functions and the hydraulic pressure is increased. The oil in the chamber 45 is discharged, and the pressure in the hydraulic chamber 45 is maintained appropriately.

Even if the pressure in the hydraulic chamber 45 is instantaneously increased due to the impact load, the outer ring 32 is provided with a plurality of O-rings 53, so that the inner peripheral surface of the bearing housing 25 and the outer periphery of the outer ring 32 are provided. Oil leakage from the gap between the surfaces can be prevented.
Further, since the preload member 36 is restricted from moving outward in the axial direction by a predetermined amount or more by the flange portion 36c coming into contact with the end surface 25a of the bearing housing 25, the hydraulic chamber 45 is set to a predetermined value or more by an impact load or the like. The oil pressure can be reduced and the oil leakage can be more reliably prevented without excessively increasing the pressure in the hydraulic chamber 45.

The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate. For example, the preload member 36 may be configured by only the cylindrical portion 36b and the closed portion 36a without the flange portion 36c. In addition, the preload member 36 can be formed individually without integrally forming the cylindrical portion 36b, the closing portion 36a, and the flange portion 36c, and can be integrally connected by appropriate connecting means (welding, screwing, etc.).
Although the rolling bearing device used for 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 is a 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

10 Transmission (Rolling bearing device)
11 Tapered roller bearings (rolling bearings)
15 Output shaft (rotary shaft)
25 Bearing housing 30 Preloading mechanism 32 Outer ring 33 Inner ring 34 Tapered roller (rolling element)
36 Preload member 36a Closure part 36b Cylindrical part 36c Flange part

Claims (1)

A rolling element, an inner ring having a raceway surface on which the rolling element rolls, and a raceway surface on which the rolling element rolls and receives a radial load from the rolling element and a load directed to one axial direction An outer ring having an inner circumference and a first linear expansion coefficient;
A preload member that integrally includes a cylindrical portion into which the outer peripheral surface of the outer ring fits and a closing portion that closes the inner peripheral side opening on the one axial side of the outer ring and has a second linear expansion coefficient. When,
A bearing housing having an inner peripheral surface with which the cylindrical portion of the preload member is fitted, and having a third linear expansion coefficient larger than the first and second linear expansion coefficients;
A rotating shaft that fits to the inner peripheral surface of the inner ring and has a fourth linear expansion coefficient smaller than the third linear expansion coefficient;
A preload application mechanism that applies a preload directed to the other side in the axial direction by the liquid pressure ,
The rolling bearing device according to claim 1, wherein the preload member includes a flange portion that faces the end surface on the other axial side of the bearing housing and can abut against the end surface .

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