JP2008101673A - Rolling bearing and rolling bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent losing pre-load due to temperature rise of a rolling bearing device by impelling an outer ring by a pressure supply means in a pre-load apply direction. <P>SOLUTION: When axial pre-load is applied to a tapered roller bearing 9, the outer ring 42 receives a component of force on a tilted rolling contact surface of a tapered roller 43 and displaces in a radial direction, and the first outer circumference surface 42b and a second outer circumference surface 42c of the outer ring 42 are pressed against an inner circumference surface of a bearing housing 40 to support the pre-load. If the temperature of the tapered roller bearing 9 rises, light metal bearing housing 40 expands more greatly than a steel main rotary shaft 4 having the tapered roller bearing 9 attached thereto. However, since pre-load is applied to the outer ring 42, an inner circumference raceway surface 42a of the outer ring 42 does not separate from a rolling contact surface of the tapered roller 43. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a rolling bearing and a rolling bearing device, and more particularly to a rolling bearing and a rolling bearing device that are used with a preload, such as a tapered roller bearing and an angular ball bearing.

In a rolling bearing used with preload such as a tapered roller bearing and an angular ball bearing, an inner ring and an outer ring are fitted into a shaft and a bearing housing, respectively, and then the preload is adjusted. If the shaft and the bearing housing are made of the same material, the dimensional change with temperature is the same and there is no significant change in the preload, and operation is performed with the preload set at the time of assembly.

For example, in a transmission for an automobile, a tapered roller bearing is adopted at its main point (for example, a final reduction gear portion). The tapered roller bearing has an advantage that it can be used with a large capacity while being compact, and also has an advantage of excellent durability against an impact load at the time of gear change or the like. However, the tapered roller bearing requires a preload for regulating the axial gap because the rolling surface of the tapered roller is inclined. By setting the axial clearance of the tapered roller bearing to be negative by preloading, the gear meshing accuracy is also improved.

By the way, in recent years, as a part of weight reduction, a transmission case is made of a light metal such as an Al alloy. Al has the highest linear expansion coefficient among the constituent materials (about 23.5 × 10 ⁻⁶ / ° C. at room temperature: hereinafter, the unit of linear expansion coefficient is abbreviated as ppm / ° C.), and steel constituting the rotating shaft (Fe-based) There is a considerable difference from the linear expansion coefficient of the material (about 12 ppm / ° C. at room temperature). Considering the possibility of usage environment of automobiles, the temperature environment to which the tapered roller bearings supporting the transmission and the rotating shaft are exposed is -40 ° C or more and 150 ° C or less at the maximum. The relative dimensional change range is also quite large. In this case, in a normal use environment other than a cold region, the temperature of the transmission is raised to a temperature range higher than room temperature, for example, 50 ° C. or higher and 80 ° C. or lower during traveling. When it is operated, the temperature rises from the time of installation, and due to the temperature increase during operation, the dimensional change of the bearing housing of the tapered roller bearing is larger than that of the rotating shaft, and the preload may be lost.

For example, as shown in FIG. 6, in the tapered roller bearing 109 in the conventional rolling bearing device, the outer ring 142 has an outer peripheral surface 142b made of a material having a larger linear expansion coefficient than that of the constituent material of the main rotary shaft 104. Is in contact with the inner peripheral surface 140a. Specifically, the main rotating shaft 104 is made of steel (for example, low alloy steel for machine structure), and the bearing housing 140 is made of light metal (for example, die cast Al alloy).

As shown in FIG. 6, when a preload in the axial direction (arrow a direction) is applied to the tapered roller bearing 109, the outer ring 142 receives a component force on the inclined rolling surface of the tapered roller 143 and also in the radial direction. The right end surface 142c and the outer peripheral surface 142b are pressed against the inner peripheral surface 140a and the inner end surface 140c of the bearing housing 140 to support the preload. However, when the bearing housing 140 is made of light metal as described above, as shown in FIG. 7, when the transmission is heated, the light metal bearing housing 140 is more than the main rotating shaft 104 to which the tapered roller bearing 109 is attached. Since it expands greatly, the inner circumferential raceway surface 142a of the outer ring 142 is separated from the rolling surface of the tapered roller 143 in the direction of arrow b. That is, there is a problem that the temperature change of the axial gap and the radial gap of the tapered roller bearing 109 in the preload state is large, and the preload is insufficient at the time of temperature rise, and noise due to rattling of the gear tends to occur.

For this reason, Patent Document 1 proposes a rolling bearing device including a preload mechanism including a plurality of pistons disposed in a bearing housing or a member provided in the bearing housing and abutted in the axial direction.

Further, in Patent Document 2, a rolling bearing device including a preload mechanism including a hydraulic chamber surrounded by a shaft (output shaft) and an inner ring, and a hydraulic pump that supplies lubricating oil to the hydraulic chamber via a lubricating oil passage. Has been proposed.
JP-A-57-33216 (page 16, FIG. 6) JP 2003-184873 (page 5-6, FIG. 4)

When the rolling bearing device described in Patent Document 1 is used in an application in which the temperature change in the axial length of the shaft is smaller than the temperature change in the axial length of the bearing housing, the oil pressure is released because the piston is pushed by the outer ring. When the hydraulic pressure is applied again, the contact point between the piston and the outer ring may change, and by pushing it axially with the hydraulic pressure as it is, the outer ring tends to tilt, and the inner ring raceway surface of the outer ring and the tapered roller come into contact with each other, The inner raceway surface of the outer ring and the tapered roller may be damaged.

In the rolling bearing device described in Patent Document 2, since a hydraulic chamber is formed between the shaft (output shaft) and the inner ring, the O-ring is in contact with the shaft on the inner peripheral surface of the inner ring, and thermal expansion is performed. With this, there is a risk of pressure oil leaking easily due to a clearance inward in the radial direction. Furthermore, by the thermal expansion of the O-ring on the inner peripheral surface of the inner ring, the inner diameter of the O-ring increases, so that the inner ring tends to tilt in the axial direction, and the inner ring tilts when moving in the axial direction by pressure oil, Friction may occur due to the contact between the inner ring and the shaft being inclined and the inner ring pressing the roller end face.

An object of the present invention is to form a hydraulic chamber by an outer ring of a rolling bearing and a bearing housing, and to supply a liquid pressure medium (oil) to the hydraulic chamber by pressure supply means, thereby preventing preload loss due to a temperature rise during operation. An object of the present invention is to provide a rolling bearing and a rolling bearing device which are prevented.

Means for Solving the Problems and Effects of the Invention

The rolling bearing according to claim 1 includes an inner ring, a rolling element, an inner circumferential raceway surface capable of applying a load in one axial direction from the rolling element, and a first outer circumferential surface formed on the other axial side. An outer ring having a second outer peripheral surface formed on one side in the axial direction and having a smaller diameter than the first outer peripheral surface, and a first connection surface connecting the first outer peripheral surface and the second outer peripheral surface; And a circumferential groove is formed on the first outer peripheral surface and the second outer peripheral surface. According to the rolling bearing of the first aspect, since a space (hydraulic chamber) into which the liquid pressure medium (oil) can be injected can be constituted only by the outer ring and the bearing housing, pressure is supplied to the space (hydraulic chamber). By injecting the liquid pressure medium (oil) from the means (hydraulic pump), the outer ring is urged in the preload application direction, and preload loss can be prevented even if the bearing housing is thermally expanded due to temperature rise. Further, since the O-ring can be disposed in the circumferential groove on the first outer circumferential surface and the circumferential groove on the second outer circumferential surface of the outer ring, the space (hydraulic chamber) can be sealed at two O-rings, and the temperature rises. Even if the bearing housing is thermally expanded, the radial gaps between the first inner peripheral surface and the second inner peripheral surface of the bearing housing and the first outer peripheral surface and the second outer peripheral surface of the outer ring can be closed. The pressure medium (oil) hardly leaks and the outer ring is less likely to tilt with respect to the bearing housing.

The rolling bearing according to claim 2 is characterized in that, in the rolling bearing according to claim 1, the rolling element is a tapered roller, and both end faces of the tapered roller do not contact the inner circumferential raceway surface of the outer ring. . According to the rolling bearing of the second aspect, since the rolling element is a tapered roller, the axial load can be sufficiently received, and when the bearing housing is thermally expanded, the outer ring is caused by the radial gap between the outer ring and the bearing housing. Since there is no wrinkle even if it tries to incline with respect to the tapered roller, the wrinkle and the end surface of the tapered roller do not wear abnormally and wear.

The rolling bearing device according to claim 3 includes a housing having a first linear expansion coefficient, a shaft having a second linear expansion coefficient smaller than the first linear expansion coefficient, an inner ring fitted to the shaft, A rolling bearing having a third linear expansion coefficient smaller than that of the outer ring fitted into the housing, and a rolling element interposed between the inner ring and the outer ring to roll. The two rolling bearing devices are arranged so that the contact angle increases from the axially inner side toward the axially outer side, wherein the outer ring of at least one of the rolling bearings is formed on the inner side in the axial direction. The first outer peripheral surface, the second outer peripheral surface formed smaller in diameter than the first outer peripheral surface on the axially outer side, and the first outer peripheral surface and the second outer peripheral surface are connected to each other. A first connecting surface, and a circumferential groove is formed in the first outer peripheral surface and the second outer peripheral surface; An O-ring having a fourth linear expansion coefficient larger than a third linear expansion coefficient is fitted in each of the peripheral groove on the first outer peripheral surface and the peripheral groove on the second outer peripheral surface, and the housing A first inner peripheral surface formed on the inner side in the axial direction and radially opposed to the first outer peripheral surface, and formed on the outer side in the axial direction and having a smaller diameter than the first inner peripheral surface. A second inner peripheral surface opposed to the outer peripheral surface in the radial direction, and a second connecting surface connecting the first inner peripheral surface and the second inner peripheral surface, the first inner peripheral surface; A hole that opens to a space that can be formed by the second outer peripheral surface, the first connection surface, and the second connection surface and that communicates with the pressure supply means is formed. According to the rolling bearing device of the third aspect, the liquid pressure medium (oil) is supplied between the second outer peripheral surface and the first connection surface of the outer ring and the first inner peripheral surface and the second connection surface of the bearing housing. Since an injectable space (hydraulic chamber) can be configured, a liquid pressure medium (oil) is injected from the pressure supply means (hydraulic pump) into the space (hydraulic chamber), so that the outer ring is attached in the preloading direction. Thus, even if the bearing housing is thermally expanded due to a temperature rise, it is possible to prevent preload loss. In addition, since the O-rings are disposed in the circumferential grooves on the first outer peripheral surface and the second outer peripheral surface of the outer ring, the space (hydraulic chamber) can be sealed at two O-rings, and the bearing rises due to temperature rise. Even if the housing is thermally expanded, the radial gaps between the first inner peripheral surface and the second inner peripheral surface of the bearing housing and the first outer peripheral surface and the second outer peripheral surface of the outer ring can be closed. There are advantages that the medium (oil) is less likely to leak and the outer ring is less likely to tilt with respect to the bearing housing. The contact angle is defined by the contact angle [nominal contact angle] described in Japanese Industrial Standards JISB 0104-1991 “Rolling Bearing Terms”.

The rolling bearing device according to claim 4 is the rolling bearing device according to claim 3, wherein the rolling bearing is a tapered roller bearing, and both end surfaces of the rolling element are not in contact with an inner circumferential raceway surface of the outer ring. Features. According to the rolling bearing device of the fourth aspect, since the rolling bearing is a tapered roller bearing, the axial load can be sufficiently received, and when the bearing housing is thermally expanded, the radial clearance between the outer ring and the bearing housing is used. Even if the outer ring is inclined with respect to the tapered roller, there is no wrinkle, so that the wrinkle and the end surface of the tapered roller do not wear abnormally and wear.

The problem that the dimensional change of the bearing housing is larger than that of the shaft due to the temperature rise during operation of the rolling bearing and the preload is released is that the outer ring of the rolling bearing and the bearing housing form a hydraulic chamber, and the pressure supply means The problem was solved by supplying a liquid pressure medium (oil) to the hydraulic chamber.

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

FIG. 1 is a cross-sectional view of an essential part showing an example of a transmission 1 in which a rolling bearing device according to Embodiment 1 of the present invention is arranged. The transmission 1 has a case 1M in which a gear box 7 is disposed. In the case 1M, an input shaft (rotation axis O2) 3 and a main rotation shaft (output shaft: rotation axis O1) 4 are arranged so as to penetrate the gear box 7, and the respective axes in the gear box 7 are arranged. Gears 30 and 31 arranged on the top mesh with each other. The rotation of the input shaft 3 is transmitted to the main rotating shaft 4 in both forward and reverse directions via gears 30 and 31. Both ends of the input shaft 3 are respectively supported by a cylindrical roller bearing 5 and a ball bearing 6 fixed inside the case 1M. On the other hand, both ends of the main rotating shaft 4 are supported by tapered roller bearings 8 and 9. Among these, the tapered roller bearing 8 on the one axial side is fixed to a bearing housing 20 integrated with the case 1M. On the other hand, the tapered roller bearing 9 on the other side in the axial direction is inserted into a bearing housing 40 integral with the case 1M, and is pre-biased in the outer ring 42 toward the one side in the axial direction. The bearing housing 40 is also integrated with the bearing housing 20 as a result of being integrated with the case 1M of the transmission 1.

In the transmission 1, the gears arranged in the gear box 7 are a plurality of input-side gears (reference numeral 31 side) arranged on the input shaft 3 and having the same number of teeth on the main rotating shaft 4. Output side gear (reference numeral 30 side), and the combination of meshes can be switched in accordance with the speed ratio to be obtained or the forward / reverse distinction (for example, in the case of a manual transmission vehicle, on the other hand). In the case of an automatic vehicle, the gears 30 and 31 may be divided into a planetary gear and a sun gear of a planetary gear mechanism).

The tapered roller bearing 8 includes a bearing housing 20 integral with the case 1M of the transmission 1, a main rotating shaft 4, an inner ring 14 fitted to the main rotating shaft 4, an outer ring 15 fitted to the bearing housing 20, The main part is composed of a plurality of tapered rollers 16 inserted so as to roll between the inner ring 14 and the outer ring 15. The tapered roller bearing 8 is disposed such that the contact angle between the tapered roller 16 and the outer ring 15 increases from the axially inner side toward the axially outer side.

In the tapered roller bearing 8, the outer peripheral surface of the outer ring 15 is in contact with the inner peripheral surface of the bearing housing 20 made of a material having a larger linear expansion coefficient than the constituent material of the main rotary shaft 4. Specifically, the main rotating shaft 4 is made of steel (for example, low alloy steel for machine structure), and the bearing housing 20 is made of light metal. The light metal is a metal containing either Al or Mg as a main component (content of 50% by mass or more), but Al or Al alloy is used from the viewpoint of workability and corrosion resistance. Specifically, an Al alloy for die casting is used as the Al alloy. In the first embodiment, the case 1M is also made of an Al alloy, and the bearing housing 20 is integrated with the inner surface of the case 1M. In the tapered roller bearing 8, the rolling elements (the tapered rollers 16) and the races (the outer ring 15 / the inner ring 14) are both made of steel (for example, bearing steel, case-hardened steel, carburized steel). Yes. The environmental temperature of the bearing in the automobile transmission 1 is in the range of −40 ° C. or higher and 150 ° C. or lower (normally reached temperature excluding cold regions and high-speed continuous operation is 50 ° C. or higher and 80 ° C. or lower). The linear expansion coefficient (first linear expansion coefficient) of Al which is a constituent main component is 23 to 24 ppm / ° C., and the linear expansion coefficient of Fe which is a main constituent constituent of the main rotary shaft 4 and the tapered roller bearing 8 (second linear expansion coefficient). (Expansion coefficient) is 12-13 ppm / ° C.

2 and 3 are enlarged cross-sectional views of a main part of the tapered roller bearing 9 in the rolling bearing device according to the first embodiment.

The tapered roller bearing 9 includes a bearing housing 40 made of a light metal (for example, an aluminum alloy for die casting) having a first linear expansion coefficient, and a steel having a second linear expansion coefficient smaller than the first linear expansion coefficient ( For example, a main rotating shaft 4 made of a low alloy steel for machine structure), an inner ring 41 fitted to the main rotating shaft 4, and a third coefficient smaller than the first linear expansion coefficient fitted to the bearing housing 40. From an outer ring 42 made of steel having a linear expansion coefficient (for example, bearing steel, case-hardened steel, carburized steel), and a plurality of tapered rollers 43 that are inserted between the inner ring 41 and the outer ring 42 and roll. Its main part is composed. The tapered roller bearing 9 is arranged so that the contact angle between the tapered roller 43 and the outer ring 42 increases from the axially inner side toward the axially outer side.

The outer ring 42 includes an inner circumferential raceway surface 42a with which the rolling surface of the tapered roller 43 abuts, a first outer circumferential surface 42b formed on the axially inner side, and a first outer circumferential surface 42b on the axially outer side. A second outer peripheral surface 42c formed with a smaller diameter, a first connecting surface 42d connecting the first outer peripheral surface 42b and the second outer peripheral surface 42c, and a right end surface 42e continuous with the second outer peripheral surface 42c. With. Further, circumferential grooves 42f and 42g are formed in the first outer circumferential surface 42b and the second outer circumferential surface 42c of the outer ring 42, respectively, and the circumferential grooves 42f and the second outer circumferential surface 42c of the first outer circumferential surface 42b are formed. In the groove 42g, rubber O-rings 44 and 45 having a fourth linear expansion coefficient larger than the third linear expansion coefficient are fitted and arranged in a compressed form.

The bearing housing 40 has a first inner peripheral surface 40a formed on the inner side in the axial direction and radially opposed to the first outer peripheral surface 42b of the outer ring 42, and a first inner periphery formed on the outer side in the axial direction. A second inner peripheral surface 40b having a smaller diameter than the surface 40a and radially opposing the second outer peripheral surface 42c of the outer ring 42, and a second inner peripheral surface 40b connecting the first inner peripheral surface 40a and the second inner peripheral surface 40b. A connection surface 40c and an inner wall surface 40d facing the right end surface 42e of the outer ring 42 are provided.

By fitting the outer ring 42 to the bearing housing 40, the first inner peripheral surface 40 a of the bearing housing 40, the first connection surface 42 d of the outer ring 42, the second outer peripheral surface 42 c of the outer ring 42, and the bearing housing 40 A hydraulic chamber 46 that is an annular space surrounded by the second connecting surface 40c is formed.

Further, the bearing housing 40 has a hole 51 forming a part of the injection path of the oil F so as to penetrate the bearing housing 40 (the right side wall as viewed in FIG. 1) in order to inject the oil F into the hydraulic chamber 46. Is formed. A plurality of holes 51 may be formed at predetermined intervals in the circumferential direction. The hydraulic chamber 46 is communicated with a hydraulic pump 52 (see FIG. 1) through a hole 51. The injection pressure (hydraulic pressure) of the oil F into the hydraulic chamber 46 by the hydraulic pump 52 becomes a preload applied to the outer ring 42, and the level of the preload can be adjusted according to the pumping pressure of the hydraulic pump 52. The hydraulic chamber 46, the hole 51, and the hydraulic pump 52 constitute a pressure supply means 50.

In the hydraulic chamber 46, the bearing housing 40 is made of an Al alloy, while the outer ring 42 is made of steel. For this reason, when the temperature rises, the first inner peripheral surface 40a and the second inner peripheral surface 40b of the bearing housing 40 and the outer peripheral surface of the outer ring 42 are caused by the difference in coefficient of linear expansion between the bearing housing 40 and the outer ring 42. This increases the axial gap and radial gap. Accordingly, the radial gap is made of rubber that seals the first inner peripheral surface 40a and the second inner peripheral surface 40b of the bearing housing 40 and the first outer peripheral surface 42b and the second outer peripheral surface 42c of the outer ring 42. The O-rings 44 and 45 are fitted and arranged in the circumferential grooves 42f and 42g in a compressed form. When the dimension of the radial gap changes due to the temperature history, the O-rings 44 and 45 can keep their close contact with the seal surface at all times by changing their elastic compression deformation amount following the change in dimension. Is possible. Thereby, even if the radial gap increases due to the thermal expansion of the bearing housing 40, the oil F is prevented from leaking from the hydraulic chamber 46 due to the arrangement of the O-rings 44 and 45. The material of the rubber used for the O-rings 44 and 45 is a rubber capable of achieving both mechanical strength and oil resistance in consideration of contact with the oil F, such as nitrile rubber (particularly hydrogenated nitrile rubber), acrylic rubber, Silicon rubber, fluorine rubber and the like are preferable.

On the other hand, in the pressure supply means 50, an excessive preload of the outer ring 42 may occur due to the temperature history. Specifically, the support positions of the first outer peripheral surface 42b and the second outer peripheral surface 42c of the outer ring 42 by the first inner peripheral surface 40a and the second inner peripheral surface 40b of the bearing housing 40 are increased in diameter by increasing the temperature. If it moves in the direction, the preload is insufficient as it is, and the axial gap and the radial gap of the tapered roller bearing 9 increase. Therefore, as described above, injection of the oil F into the hydraulic chamber 46 causes the outer ring 42 to be displaced in a direction in which the axial gap and the radial gap are reduced, that is, in a direction in which the hydraulic chamber 46 is enlarged. However, when the temperature decreases in this state, the bearing housing 40 having a linear expansion coefficient smaller than that of the main rotating shaft 4 contracts, and the volume of the hydraulic chamber 46 filled with the oil F also decreases.

Therefore, in the pressure supply means 50, the pressure discharge means 55 branches off from the injection path between the hydraulic pump 52 and the hydraulic chamber 46. The pressure discharge means 55 is connected to a tank or a discharge container (not shown) for storing the oil F supplied to the hydraulic pump 52. When the oil F supplied to the hydraulic chamber 46 is the same as the lubricating oil used in the transmission 1, the oil F can be discharged into the transmission 1. As the pressure discharge means 55, for example, an opening / closing means such as an electromagnetic valve or a check 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 (not shown) for monitoring the internal pressure in the pressure supply means 50 (the internal pressure of the hydraulic chamber 46 and the hole 51, the pumping pressure of the hydraulic pump 52) is further provided, and the internal pressure rises excessively. When this occurs, the solenoid valve is opened by the output of the pressure sensor, so that the oil F is discharged and the internal pressure is made appropriate. In the case of a check valve, it is set in advance so that it opens when the internal pressure in the pressure supply means 50 exceeds a certain pressure. In the case of an orifice or needle, it is set so that an appropriate internal pressure can be obtained. Further, instead of the check valve, a stop valve constituted by an electromagnetic valve or the like is provided, and on the other hand, a pressure sensor is disposed in the hydraulic chamber 46, and the reverse thrust is detected by the internal pressure of the hydraulic chamber 46 detected by the pressure sensor. Generation may be detected, and a stop valve may be operated to block outflow of oil F from the injection path. Furthermore, a method of changing the pressure of the oil F fed by the hydraulic pump 52 in accordance with the internal pressure of the hydraulic chamber 46 detected by the pressure sensor is also possible. In this case, when reverse thrust is generated, the pumping pressure of the oil F is increased to block outflow of the oil F from the injection path. Therefore, a check valve or a stop valve is not necessary.

Of course, the pressure discharge means 55 can be disposed on the injection path of the oil F connecting the hydraulic pump 52 and the hydraulic chamber 46, or the hydraulic pump 52 itself has a built-in check valve. If so, you can use it. However, if the elastic deformation allowance of the injection path of the oil F and the oil pumping space of the hydraulic pump 52 is large, the backflow of the oil F is allowed by the deformation allowance, and the effect of positioning the outer ring 42 may be impaired. There is also. Therefore, it can be said that the pressure discharge means 55 is desirably provided as close as possible to the hydraulic chamber 46.

Next, operation | movement of the rolling bearing apparatus based on Example 1 comprised in this way is demonstrated.

A preload in the axial direction is applied to the outer ring 42 through the hydraulic chamber 46 by the hydraulic pressure from the hydraulic pump 52. In this state, as shown in FIG. 2, the outer ring 42 receives a component force on the inclined rolling surface of the tapered roller 43 and is displaced in the axial direction and the radial direction. The first outer peripheral surface 42b and the second outer peripheral surface 42d are pressed against and supported by the first inner peripheral surface 40a and the second inner peripheral surface 40b of the bearing housing 40, respectively.

The main rotating shaft 4 rotates in the forward direction during forward driving and in the reverse direction during backward driving. The direction in which the preload is applied from the bearing housing 40 to the outer ring 42 is made to coincide with the thrust direction of the gears 30 and 31 when rotating in the forward direction. As a result, the outer ring 42 receives the thrust from the gears 30 and 31 as a forward thrust that coincides with the preload application direction when the main rotating shaft 4 is rotated forward, while the outer ring 42 receives from the gears 30 and 31 when the main rotating shaft 4 is rotated reversely. This thrust is received as a reverse thrust opposite to the preload application direction. For this reason, when the main rotating shaft 4 rotates reversely, such as when the automobile is moving backward, the thrust of the gears 30 and 31 is applied in the opposite direction to the preload application direction. Then, the outer ring 42 is pushed back in the direction opposite to the preload application direction by the reverse direction thrust. In order for the outer ring 42 to move backward, the volume of the hydraulic chamber 46 must be reduced, and the oil F in the hydraulic chamber 46 needs to flow out from the hole 51 to the hydraulic pump 52 side. The oil F about to flow back to the hydraulic pump 52 is discharged from an injection path through a pressure discharge means 55 to a tank or a discharge container (not shown) and stored.

If the temperature of the transmission 1 is kept relatively constant at a relatively low temperature, the position of the outer ring 42 in the preload application direction does not change much, and the level of the preload applied to the outer ring 42 by the hydraulic pressure from the hydraulic pump 52 is also substantially constant. Kept.

When the temperature of the transmission 1 rises, the linear expansion coefficient of the bearing housing 40 is larger than the linear expansion coefficient of the main rotary shaft 4, so that the bearing housing 40 expands in the radial direction, and the first inner peripheral surface 40 a and the second The inner peripheral surface 40b of the outer peripheral surface of the tapered roller bearing 9 is increased in diameter, and tends to be separated from the first outer peripheral surface 42b and the second outer peripheral surface 42c of the outer ring 42 which is the bearing outer diameter surface of the tapered roller bearing 9. That is, the support positions of the first outer peripheral surface 42b and the second outer peripheral surface 42c of the outer ring 42 by the first inner peripheral surface 40a and the second inner peripheral surface 40b of the bearing housing 40 change radially outward, The reaction force applied to the outer ring 42 by the bearing housing 40 is reduced. Then, the outer ring 42 moves to a position where the preload that is the hydraulic pressure by the hydraulic pump 52 and the reaction force from the bearing housing 40 are balanced. As a result, even if the support positions of the first outer peripheral surface 42b and the second outer peripheral surface 42c of the outer ring 42 move due to the temperature rise, the preload on the outer ring 42 is kept substantially constant. For this reason, the first outer peripheral surface 42b of the outer ring 42 formed by the first inner peripheral surface 40a and the second inner peripheral surface 40b of the bearing housing 40 is derived from the difference in linear expansion coefficient between the bearing housing 40 and the main rotary shaft 4. And the temperature change of the support position of the 2nd outer peripheral surface 42c is absorbed. That is, even if the temperature change of the axial gap and the radial gap of the tapered roller bearing 9 in the preload state is large, the preload does not become insufficient when the temperature rises, and the inner circumferential raceway surface 42a of the outer ring 42 rolls the tapered roller 43. There is no separation from the surface, and noise caused by rattling of the gears 30 and 31 is also suppressed.

When the transmission 1 is heated, the bearing housing 40 is thermally expanded in the axial direction, and the internal pressure of the hydraulic chamber 46 is reduced. When a reduction in the internal pressure of the hydraulic chamber 46 is detected by a pressure sensor provided in the hydraulic chamber 46, the oil F in the hydraulic chamber 46 is pressurized by the hydraulic pump 52. When the oil F in the hydraulic chamber 46 is pressurized to a predetermined pressure, it is detected by the pressure sensor, and the pressurization of the oil F in the hydraulic chamber 46 by the hydraulic pump 52 is stopped.

On the other hand, when the temperature of the transmission 1 is lowered, the bearing housing 40 is thermally contracted in the axial direction and the radial direction, the hydraulic chamber 46 is contracted, and the oil F in the hydraulic chamber 46 is pressurized. When the oil F in the hydraulic chamber 46 is pressurized, the pressure discharge means 55 including a check valve is operated, and the oil F is discharged and stored in a tank or a discharge container (not shown).

2, when an impact load or the like in the direction opposite to the preload application direction (see arrow c in FIG. 3) is applied to the main rotating shaft 4 via the inner ring 41 and the tapered roller 43. When the outer ring 42 moves in the axial direction against the hydraulic pressure by the hydraulic pump 52, an impact load or the like is buffered and suppressed. At this time, the oil F in the hydraulic chamber 46 flows out from the hole 51 to the hydraulic pump 52 side, and is discharged and stored in a tank or a discharge container (not shown) through the pressure discharge means 55 from the injection path. Further, even in the worst case where an excessive impact load exceeding the moving range of the outer ring 42 is applied, as shown in FIG. 3, the right end surface 42e of the outer ring 42 is formed on the inner wall surface 40d of the bearing housing 40 (case 1M). The impact load or the like is received by contact.

According to the first embodiment, the oil F can be injected by the second outer peripheral surface 42c and the first connecting surface 42d of the outer ring 42 and the first inner peripheral surface 40a and the second connecting surface 40c of the bearing housing 40. Since the hydraulic chamber 46 is formed and oil F is injected into the hydraulic chamber 46 from the hydraulic pump 52 to urge the outer ring 42 in the preload application direction, the preload is applied even if the bearing housing 40 is thermally expanded due to a temperature rise. Omission can be prevented.

Further, the O-rings 44 and 45 are fitted and arranged in a compressed form in the peripheral grooves 42f and 42g of the first outer peripheral surface 42b and the second outer peripheral surface 42c of the outer ring 42, so that the hydraulic chamber 46 has two O-rings. The outer ring 42 can be hardly tilted with respect to the bearing housing 40. In addition, even if the bearing housing 40 is thermally expanded due to a temperature rise, the first inner peripheral surface 40a and the second inner peripheral surface 40b of the bearing housing 40 and the first of the outer ring 42 are restored by elastic recovery of the O-rings 44 and 45. Since the radial gap between the outer peripheral surface 42b and the second outer peripheral surface 42c can be closed, the effect that the oil F hardly leaks is obtained.

Further, since the rolling bearing is the tapered roller bearing 9, it can sufficiently receive an axial load, and when the bearing housing 40 is thermally expanded, the outer ring 42 is tapered by the radial gap between the outer ring 42 and the bearing housing 40. However, since there is no wrinkle even if it tries to incline, there is an advantage that the wrinkle and the end face of the tapered roller 43 do not wear abnormally.

FIG. 4 is a cross-sectional view of a main part showing a tapered roller bearing 9 ′ in the rolling bearing device according to the second embodiment of the present invention. In the rolling bearing device according to the first embodiment, the hydraulic pump 52 communicating with the hydraulic chamber 46 through the hole 51 is provided as the pressure supply means 50 to the tapered roller bearing 9. However, the rolling bearing device according to the second embodiment is provided. In the bearing device, a compression coil spring 53 for urging the outer ring 42 in the preload application direction is added as a pressure supply means 50 to the tapered roller bearing 9 ′.

The compression coil spring 53 is disposed in the hydraulic chamber 46, and one end thereof is in contact with the first connection surface 42 d of the outer ring 42 and the other end is in contact with the second connection surface 40 c of the bearing housing 40. The compression coil spring 53 urges the outer ring 42 in the preload application direction in cooperation with the hydraulic pressure from the hydraulic pump 52. By disposing the compression coil spring 53 in the hydraulic chamber 46, the pressure supply means 50 is greatly reduced in size. That is, in the configuration in which the hydraulic chamber 46 and the compression coil spring 53 are used together as the pressure supply means 50, when a predetermined preload is obtained, the hydraulic pressure by the hydraulic pump 52 is increased by the amount of the spring repulsion force of the compression coil spring 53. The pressure can be reduced (a small hydraulic pump 52 can be used), and the pressure supply means 50 can be made compact as a whole. In particular, since the compression coil spring 53 is disposed in the hydraulic chamber 46, there is no space in appearance, and space can be saved from this point. Considering that the compression coil spring 53 is disposed in a state where it is always in contact with the oil F in the hydraulic chamber 46, it is preferable to use spring steel or beryllium copper rather than rubber or plastic that may swell due to oil absorption. It is more advantageous from the viewpoint of durability to use a metal material for springs.

In addition, since the part which is not mentioned especially is comprised similarly to the rolling bearing apparatus in Example 1, the same code | symbol is attached | subjected to a corresponding part and those detailed description is abbreviate | omitted.

Next, the operation of the rolling bearing device according to the second embodiment configured as described above will be described with a focus on differences from the operation of the rolling bearing device according to the first embodiment.

In the state where the axial ring preload is applied to the outer ring 42 by the hydraulic pressure from the hydraulic pump 52 and the spring repulsive force from the compression coil spring 53, the outer ring 42 has an inclined rolling surface of the tapered roller 43 as shown in FIG. 4. The axial force and the radial direction are displaced in response to the above-described component force, and the first outer peripheral surface 42b and the second outer peripheral surface 42d of the outer ring 42 are displaced in the radial direction by the preload in the radial direction. And supported by being pressed against the second inner peripheral surface 40b.

If the temperature of the transmission 1 is kept relatively constant at a relatively low temperature, the position of the outer ring 42 in the preload application direction does not change so much and is given to the outer ring 42 by the hydraulic pressure by the hydraulic pump 52 and the spring repulsive force by the compression coil spring 53. The level of preload applied is also kept almost constant.

When the temperature of the transmission 1 rises, the linear expansion coefficient of the bearing housing 40 is larger than the linear expansion coefficient of the main rotating shaft 4, so that the first inner peripheral surface 40 a and the second inner peripheral surface 40 b of the bearing housing 40 are expanded. The outer peripheral surface 42b and the second outer peripheral surface 42c of the outer ring 42, which are the outer diameter surfaces of the tapered roller bearing 9 ', are going to be separated from each other. That is, the support positions of the first outer peripheral surface 42b and the second outer peripheral surface 42c of the outer ring 42 by the first inner peripheral surface 40a and the second inner peripheral surface 40b of the bearing housing 40 change radially outward, The reaction force applied to the outer ring 42 by the bearing housing 40 is reduced. Then, the outer ring 42 moves to a position where the preload, which is the sum of the hydraulic pressure by the hydraulic pump 52 and the spring repulsive force by the compression coil spring 53, and the reaction force from the bearing housing 40 are balanced. As a result, even if the support positions of the first outer peripheral surface 42b and the second outer peripheral surface 42c of the outer ring 42 move due to the temperature rise, the preload on the outer ring 42 is kept substantially constant. For this reason, the first outer peripheral surface 42b of the outer ring 42 formed by the first inner peripheral surface 40a and the second inner peripheral surface 40b of the bearing housing 40 is derived from the difference in linear expansion coefficient between the bearing housing 40 and the main rotary shaft 4. And the temperature change of the support position of the 2nd outer peripheral surface 42c is absorbed. That is, even if the temperature change of the axial gap and the radial gap of the tapered roller bearing 9 ′ in the preload state is large, the preload does not become insufficient when the temperature rises, and the inner circumferential raceway surface 42 a of the outer ring 42 does not rotate the tapered roller 43. There is no separation from the moving surface, and noise caused by rattling of the gears 30 and 31 is also suppressed.

When the transmission 1 is heated, the bearing housing 40 is thermally expanded in the axial direction and the radial direction, and the internal pressure of the hydraulic chamber 46 is reduced. When a reduction in the internal pressure of the hydraulic chamber 46 is detected by a pressure sensor provided in the hydraulic chamber 46, the oil F in the hydraulic chamber 46 is pressurized by the hydraulic pump 52. When the oil F in the hydraulic chamber 46 is pressurized to a predetermined pressure, it is detected by a pressure sensor provided in the hydraulic chamber 46, and the pressurization of the oil F in the hydraulic chamber 46 by the hydraulic pump 52 is stopped. .

On the other hand, when the temperature of the transmission 1 is lowered, the bearing housing 40 is thermally contracted in the axial direction and the radial direction, and the oil F in the hydraulic chamber 46 is pressurized. When the oil F in the hydraulic chamber 46 is pressurized, the pressure discharge means 55 including a check valve is operated, and the oil F is discharged and stored in a tank or a discharge container (not shown).

In the state shown in FIG. 2, when an impact load or the like in the direction opposite to the preloading direction is applied to the main rotating shaft 4, the outer ring 42 is hydraulically operated by the hydraulic pump 52 via the inner ring 41 and the tapered roller 43. Further, by moving in the axial direction against the preload which is the sum of the spring repulsion force by the compression coil spring 53, the impact load or the like is buffered and suppressed. At this time, the oil F in the hydraulic chamber 46 flows out from the hole 51 to the hydraulic pump 52 side, and is discharged from the injection path to a tank or a discharge container (not shown) through the pressure discharge means 55 including a check valve. And stored. Even in the worst case where an excessive impact load exceeding the movement range of the outer ring 42 is applied, the right end surface 42e of the outer ring 42 abuts against the inner wall surface 40d of the bearing housing 40 (case 1M) and the impact load or the like is generated. It will be accepted.

According to the second embodiment, in addition to the effects obtained in the first embodiment, since the compression coil spring 53 is disposed in the hydraulic chamber 46, not only the hydraulic pressure by the hydraulic pump 52 but also the compression coil spring 53 is used. Since the spring repulsion force is applied to the outer ring 42 as a preload, even when a strong reverse thrust is applied, an effect that the preload is not insufficient is obtained. In particular, since only the compression coil spring 53 is additionally provided in the hydraulic chamber 46, there is an advantage that the preload applied to the outer ring 42 can be enhanced with a very simple structure.

In each of the above-described embodiments, the pressure supply means 50 including the hydraulic pump 52 and the pressure discharge means 55 (in addition to the compression coil spring 53) is provided only on the tapered roller bearings 9 and 9 'on one axial side of the rolling bearing device. However, as shown in FIG. 5, the tapered roller bearing 8 can be provided with the same pressure supply means 50. Even if it does in this way, it cannot be overemphasized that the effect similar to each Example is acquired. In this case, the hydraulic pump 52 and the pressure discharge means 55 may be provided in the pressure supply means 50 of the tapered roller bearing 8 and the pressure supply means 50 of the tapered roller bearing 9, respectively, or one may be used in common. , One can be common and the other can be separate.

As mentioned above, although each example of the present invention was described, these are only illustrations, the present invention is not limited to these, and the knowledge of those skilled in the art can be used without departing from the spirit of the claims. Various modifications based on this are possible.

For example, in each of the embodiments, the rolling bearing device used for the transmission 1 has been described as an example, but the rolling bearing device used for other devices such as a gear unit for a drive distribution shaft to each wheel of a four-wheel drive vehicle may also be used. Needless to say, the present invention can be similarly applied.

In each embodiment, the rolling bearing used in the rolling bearing device is a tapered roller bearing, but other rolling bearings that are used with a preload such as an angular ball bearing, a deep groove ball bearing, Needless to say, the present invention can be similarly applied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an essential part cross-sectional view illustrating an example of a transmission in which a rolling bearing device according to a first embodiment of the present invention is disposed. FIG. 3 is a cross-sectional view of a main part of the tapered roller bearing in the first embodiment. FIG. 3 is a cross-sectional view of a main part of the tapered roller bearing in the first embodiment. Sectional drawing of the principal part of the tapered roller bearing in the rolling bearing apparatus which concerns on Example 2 of this invention. The principal part sectional drawing which shows the modification of the transmission by which the rolling bearing apparatus which concerns on Example 1 of this invention was arrange | positioned. Sectional drawing of the principal part of the tapered roller bearing in the conventional rolling bearing apparatus. Sectional drawing of the principal part of the tapered roller bearing in the conventional rolling bearing apparatus.

Explanation of symbols

1 Transmission 3 Input shaft 4 Main rotating shaft 8, 9, 9 'Tapered roller bearing (rolling bearing)
40 Bearing housing (housing)
40a First inner peripheral surface 40b Second inner peripheral surface 40c Second connecting surface 40d Inner wall surface 41 Inner ring 42 Outer ring 42a Inner peripheral raceway surface 42b First outer peripheral surface 42c Second outer peripheral surface 42d First connecting surface 42e Right end face 42f, 42g Circumferential groove 43 Tapered roller (rolling element)
44, 45 O-ring 46 Hydraulic chamber (space)
50 Pressure supply means 51 Hole 52 Hydraulic pump 53 Compression coil spring 55 Pressure discharge means F Oil (liquid pressure medium)

Claims (4)

An inner ring, a rolling element, an inner circumferential raceway surface capable of applying a load in one axial direction from the rolling element, a first outer circumferential surface formed on the other axial side, and formed on one axial side A second outer peripheral surface having a smaller diameter than the first outer peripheral surface, and an outer ring provided with a first connection surface connecting the first outer peripheral surface and the second outer peripheral surface;
A rolling bearing, wherein a circumferential groove is formed in the first outer peripheral surface and the second outer peripheral surface. The rolling bearing according to claim 1, wherein the rolling element is a tapered roller, and both end surfaces of the tapered roller do not contact the inner circumferential raceway surface of the outer ring. A housing having a first linear expansion coefficient, a shaft having a second linear expansion coefficient smaller than the first linear expansion coefficient, an inner ring fitted to the shaft, and a third smaller than the first linear expansion coefficient A rolling bearing provided with an outer ring having a linear expansion coefficient and fitted into the housing, and a rolling element that is inserted between the inner ring and the outer ring to roll, the contact angle of the rolling bearing from the inner side in the axial direction. Two rolling bearing devices arranged so as to expand toward the outside in the direction,
The outer ring of at least one rolling bearing has a first outer peripheral surface formed on the inner side in the axial direction, a second outer peripheral surface formed on the outer side in the axial direction with a smaller diameter than the first outer peripheral surface, And a first connecting surface that connects the first outer peripheral surface and the second outer peripheral surface, and a circumferential groove is formed in the first outer peripheral surface and the second outer peripheral surface, An O-ring having a fourth linear expansion coefficient larger than the third linear expansion coefficient is fitted in the peripheral groove on the outer peripheral surface and the peripheral groove on the second outer peripheral surface,
The housing is formed on the inner side in the axial direction and has a first inner peripheral surface facing the first outer peripheral surface in the radial direction, formed on the outer side in the axial direction and having a smaller diameter than the first inner peripheral surface. A second inner peripheral surface opposed to the second outer peripheral surface in the radial direction; and a second connecting surface connecting the first inner peripheral surface and the second inner peripheral surface; A hole that opens to a space that can be formed by a peripheral surface, the second outer peripheral surface, the first connection surface, and the second connection surface and that communicates with the pressure supply means is formed. Rolling bearing device. The rolling bearing device according to claim 3, wherein the rolling bearing is a tapered roller bearing, and both end surfaces of the rolling element do not contact an inner circumferential raceway surface of the outer ring.

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