JP2008215485A - Tapered roller bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tapered roller bearing device for making both of torque reduction and seizure resistance compatible, by preventing the occurrence of seizure of a large collar part, even if a lubricating oil quantity inside of a tapered roller bearing is largely reduced. <P>SOLUTION: This tapered roller bearing device 1 has an outer ring 2 installed in a housing, an inner ring 3 installed on a rotary shaft 10, a plurality of tapered rollers 4 arranged between both rings 2 and 3, a cage 4 holding the tapered rollers 4, and a cylindrical heat radiating member 6 installed on the rotary shaft 10 and releasing heat of the inner ring 3 to the rotary shaft 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tapered roller bearing device, and more particularly, a tapered roller that supports a pinion shaft in an automobile final reduction gear (differential device) and the like and is lubricated by using lubricating oil contained in the device. The present invention relates to a bearing device.

  A tapered roller bearing (see Patent Document 1) having a plurality of tapered rollers disposed between an outer ring, an inner ring, and both wheels, and a cage that holds these tapered rollers (see Patent Document 1) is compact and supports large radial loads and axial loads. In addition, since it can be used at high speed rotation, as shown in Patent Document 2, it is widely used in a pinion shaft support device for vehicles.

  FIG. 4 shows an example of a differential gear device to which the tapered roller bearing device according to the present invention is applied. The differential gear device is rotatably supported by a housing (41) and has a pinion gear at the rear end. A pinion shaft (42) provided with (43), a ring gear (44) meshed with the pinion gear (43), and an inner / outer pair for rotatably supporting the pinion shaft (42) on the housing (41) Tapered roller bearings (45) and (46), and a drive shaft coupling flange joint (47) provided at the outer end of the pinion shaft (42).

In this differential gear device, the lubricating oil splashed with the rotation of the ring gear (44) is passed through the lubricating oil passage (48) in the housing (41), and a pair of tapered roller bearings (45) (46). ). When the tapered roller bearing (45) (46) rotates, fluid flow (pump action) from the inner ring small flange side to the large flange side occurs, so the tapered roller bearing (45) (46) for the differential gear unit Then, a lubrication method in which oil is supplied from the small collar side of the inner ring and oil is discharged to the large collar side using this pump action is generally applied.
JP 2004-76766 A JP 2000-170775 A

  In the above conventional lubrication method, the lubricating oil can be easily introduced into the tapered roller bearing. However, since most of the oil flows to the outer ring side by centrifugal force at high speed, the lubricating oil is near the large collar portion of the inner ring. It does not spread, and heat is generated at the sliding contact part with the large end of the inner ring, and the generated heat is difficult to remove, so seizure is likely to occur (local temperature rise is likely to occur). .

  On the other hand, in pinion shaft support devices for vehicles and the like, reduction of the rotational torque of tapered roller bearings has become a global issue in order to reduce loss. In order to reduce the rotational torque, it is effective to reduce the amount of lubricating oil passing through the bearing and suppress the stirring resistance due to the lubricating oil. However, if the amount of the lubricating oil is reduced, the risk of seizure of the large collar portion described above increases, so that a large amount of lubricating oil is currently supplied to the tapered roller bearing.

  An object of the present invention is to provide a tapered roller bearing device that achieves both low torque and seizure resistance, assuming that seizure of the large collar portion is unlikely to occur even if the amount of lubricating oil inside the tapered roller bearing is significantly reduced. It is to provide.

  The tapered roller bearing device according to the present invention includes an outer ring, an inner ring, a plurality of tapered rollers disposed between the two rings, and a retainer for holding these tapered rollers, and the tapered roller bearing in which the inner ring is attached to a rotating shaft. The apparatus further includes a heat dissipating member made of a material that is in contact with both the large flange side end of the inner ring and the rotating shaft and has a higher thermal conductivity than the rotating shaft.

  The large flange portion of the inner ring of the tapered roller bearing becomes hotter than the rotating shaft due to frictional heat generated between the inner ring large flange surface and the end surface, and the heat of the inner ring is released to the rotating shaft side by the heat radiating member. Sticking is suppressed. The heat dissipating member is formed in a cylindrical shape whose inner peripheral surface is in contact with the rotating shaft, and is brought into contact with at least a part of the large flange side end surface (back surface) of the tapered roller bearing inner ring.

  The basic shape of the heat radiating member is a cylindrical body, but may be various shapes, and the shape of the rotating shaft and / or inner ring may be partially changed in accordance with the shape of the heat radiating member. The area where the heat radiating member is in contact with the rotating shaft is preferably larger than the area where the heat radiating member is in contact with the inner ring. The heat radiating member may be composed of, for example, a cylindrical portion, an inward flange portion provided at one end inner diameter of the cylindrical portion, and an annular projecting portion provided at one end outer diameter of the cylindrical portion, There may be a cylindrical portion, an inward flange portion provided on an inner diameter of one end portion of the cylindrical portion, and an annular projecting portion protruding in the axial direction from the inward flange portion. In the latter case, the inner ring is provided with an annular notch for accommodating the annular protrusion of the heat dissipation member.

  The heat radiating member is preferably formed of an aluminum alloy or a magnesium alloy.

  The rotating shaft is usually made of steel such as carbon steel, and the inner ring is usually made of steel such as bearing steel. The thermal conductivity of carbon steel is 42 W / m · k (Watts / meter x Kelvin). When the rotating shaft is carbon steel, the material of the heat radiating member has a thermal conductivity greater than 42 W / m · k. Is used. Regarding thermal conductivity, for example, brass is 60 W / m · k, copper is 170 W / m · k, pure magnesium is 156 W / m · k (specific heat capacity is 1020 J / kg · K), and pure aluminum is 237 W / m · k. k (specific heat capacity is 900 J / kg · K), magnesium alloy AZ91 is 72 W / m · k, magnesium alloy AM60 is 62 W / m · k, aluminum alloy (die cast) 380 is 100 W / m · k, aluminum The alloy (die-cast) ADC12 is 92 W / m · k, and the aluminum alloy (die-cast) 6063 is 220 W / m · k. Therefore, all the materials exemplified above can be used as the material of the heat dissipation member. Of these, magnesium alloys are suitable as heat-dissipating materials because of their superior resistance to deformation, good vibration and shock absorption characteristics, and small dimensional changes, and aluminum alloys are suitable for heat conduction. It is suitable as a heat dissipating material because of its large point.

  According to the tapered roller bearing device of the present invention, the heat dissipating member in contact with the large collar part of the inner ring makes it easy for the frictional heat generated in the large collar part that is easily seized to escape to the rotating shaft, and seizure of this part is suppressed. Therefore, the amount of lubricating oil can be reduced, and the friction loss of the bearing can be reduced. Therefore, both low torque and seizure resistance can be achieved.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the left and right refer to the left and right in the figure.

  FIG. 1 shows a first embodiment of a tapered roller bearing device according to the present invention. The tapered roller bearing device (1) is disposed between an outer ring (2) attached to a housing (not shown), an inner ring (3) attached to a rotating shaft (10), and both wheels (2) (3). A plurality of tapered rollers (4), a cage (5) that holds the tapered rollers (4), and a cylindrical shape that is attached to the rotating shaft (10) and releases the heat of the inner ring (3) to the rotating shaft (10). And a heat dissipating member (6).

  The inner ring (3) is provided at the left end portion of the tapered raceway surface (3a) and provided at the right end portion and a small flange portion (3b) for restricting axial movement of the tapered roller (4). A large collar portion (3c) for restricting the axial movement of the tapered roller (4) is provided.

  The outer ring (2) has a conical raceway surface (2a), its right end surface is inward of the right end surface of the inner ring (3), and its left end surface is the left end of the inner ring (3). It is said to be flush with the surface.

  The cage (5) has a large-diameter end (5a) projecting to the right of the tapered roller (4) and a small-diameter end (5b) projecting to the left. The end (5b) is bent inward in the radial direction, and faces the small collar part (3b) of the inner ring (3) with a slight gap.

  The rotating shaft (10) has a small diameter part (10a) in which the inner ring (3) is fitted, and a large diameter part (10b) connected to the right side of the small diameter part (10a) via a step part (10c). And the right end surface of the inner ring (3) is received by the step portion (10c).

  The tapered roller bearing portion and the rotating shaft (10) other than the heat dissipating member (6) are known, and the tapered roller bearing is made of, for example, bearing steel, and the rotating shaft (10) is made of, for example, carbon steel. The

  The left end surface of the heat dissipating member (6) is brought into contact with the large collar side end surface (rear surface) of the inner ring (3), and the inner peripheral surface thereof is brought into contact with the outer peripheral surface of the rotating shaft (10). . The heat radiating member (6) is made of a material (aluminum alloy, magnesium alloy, etc.) having a higher thermal conductivity than the rotating shaft (10).

  According to this tapered roller bearing device (1), the large collar part (3c) of the inner ring (3) is more than the rotating shaft (10) by frictional heat generated between the inner ring (3) large collar surface and (4) end surfaces. When the temperature of the inner ring (3) is increased and the heat of the inner ring (3) is released to the rotating shaft (10) side by the heat radiating member (6), seizure is suppressed.

  FIG. 2 shows a second embodiment of the tapered roller bearing device according to the present invention. In the tapered roller bearing device (11), the shape of the heat radiating member (16) is different from that of the first embodiment, and the shape of the rotating shaft (10) is also slightly different. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The heat radiating member (16) of this embodiment includes a cylindrical portion (16a), an inward flange portion (16b) provided on the inner diameter of the left end portion of the cylindrical portion (16a), and an outer diameter of the left end portion of the cylindrical portion (16a). Are formed from a material (aluminum alloy, magnesium alloy, etc.) having a higher thermal conductivity than the rotating shaft (10).

  The rotating shaft (10) has a stepped portion (10d) on the basis of the first embodiment in order to form a space in which the inward flange portion (16b) of the heat radiating member (16) is just inserted. It has been moved to the right. The left end surface of the cylindrical portion (16a) of the heat radiating member (16) and the left surface of the inward flange portion (16b) are brought into contact with the large end surface (back surface) of the inner ring (3). The inner peripheral surface of the cylindrical portion (16a) of 16) is the outer peripheral surface of the large-diameter portion (10b) of the rotary shaft (10), and the inner peripheral surface of the inward flange portion (16b) is the small-diameter portion of the rotary shaft (10). (10a) is brought into contact with the outer circumferential surface, and the inner circumferential surface of the annular protrusion (16c) of the heat dissipating member (16) is brought into contact with the radially outer circumferential surface of the large collar portion (3c) of the inner ring (3). ing.

  According to the tapered roller bearing device (11) of the second embodiment, as in the first embodiment, the heat of the inner ring (3) is released to the rotating shaft (10) side by the heat radiating member (16). Seizure is suppressed. Compared with the heat dissipation member (6) of the first embodiment, the heat dissipation member (16) has a larger area in contact with the inner ring (3) and an area in contact with the rotary shaft (10). A high heat dissipation effect can be obtained.

  In addition, the heat dissipating member (16) is located near the sliding contact part of the large collar (3c), which is the main heat source, so that heat is not dissipated from the heat dissipating member (16) without staying in the inner ring (3). Is done.

  FIG. 3 shows a third embodiment of the tapered roller bearing device according to the present invention. In this tapered roller bearing device (21), the shape of the heat dissipating member (26) is different from that of the first embodiment, and the shapes of the inner ring (3) and the rotating shaft (10) are also slightly different. ing. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The heat radiating member (26) of this embodiment includes a cylindrical portion (26a), an inward flange portion (26b) provided on the inner diameter of the left end portion of the cylindrical portion (26a), and a left surface of the inward flange portion (26b). It consists of a provided annular protrusion (26c) and is made of a material (aluminum alloy, magnesium alloy, etc.) having a higher thermal conductivity than the rotating shaft (10).

  As in the second embodiment, the rotating shaft (10) is based on that of the first embodiment in order to form a space in which the inward flange portion (26b) of the heat radiating member (26) is just inserted. Thus, the step portion (10d) is moved to the right. Further, an annular notch (3d) into which the annular protrusion (26c) of the heat radiating member (26) is just fitted is provided on the inner diameter of the large collar (3c) of the inner ring (3). The left end surface of the cylindrical portion (26a) of the heat dissipating member (26) is brought into contact with the large flange side end surface (rear surface) of the inner ring (3) and the inner end of the cylindrical portion (26a) of the heat dissipating member (26) The peripheral surface is brought into contact with the outer peripheral surface of the large-diameter portion (10b) of the rotating shaft (10), and the inner peripheral surface of the inward flange portion (26b) is brought into contact with the outer peripheral surface of the small-diameter portion (10a) of the rotating shaft (10). Furthermore, the outer peripheral surface and the left surface of the annular protrusion (26c) of the heat radiating member (26) are on the surface forming the notch (3d) of the inner ring (3), and the inner peripheral surface is the rotating shaft (10). The small diameter portion (10a) is in contact with the outer peripheral surface.

  According to the tapered roller bearing device (11) of the third embodiment, as in the first embodiment, the heat of the inner ring (3) is released to the rotating shaft (10) side by the heat radiating member (26). Seizure is suppressed. Compared with the heat radiating member (6) of the first embodiment, the heat radiating member (26) has a larger area in contact with the inner ring (3) and an area in contact with the rotating shaft (10). A high heat dissipation effect can be obtained.

  The tapered roller bearing devices (1), (11), and (21) of the present invention are suitable as bearing devices that rotatably support the pinion shaft (42) on the housing (41) in the differential gear device of the automobile shown in FIG. Used for. The tapered roller bearing devices (1), (11), and (21) are lubricated by using lubricating oil contained in the housing (41), and at this time, pass through the tapered roller bearing to reduce rotational torque. The amount of lubricating oil is reduced, and the stirring resistance due to the lubricating oil is suppressed. Reducing the amount of lubricating oil increases the risk of seizure of the large collar part (3c) of the inner ring (3), but the heat dissipating members (6) (16) (26) cause the heat of the large collar part (3c) to (10) Since it is released to the pinion shaft (42 in Fig. 4), even if the amount of lubricating oil inside the tapered roller bearing is greatly reduced, seizure of the large collar part (3c) is difficult to occur, and low Both torque and seizure resistance are achieved.

  In FIG. 4, the flange joint (47) is in contact with the inner ring of the tapered roller bearing (46) on the right side of the figure. This flange joint (47) is more heated than the pinion shaft (42). Such as the heat dissipating members (6), (16), (26), which are made of a material (aluminum alloy, magnesium alloy, etc.) having low or the same conductivity and higher thermal conductivity than the rotating shaft (10) It does not have a heat dissipation effect.

  Needless to say, the configuration including the heat dissipating member of the present invention can also be applied to a device using a ball bearing, a cylindrical roller bearing or the like other than a tapered roller bearing.

FIG. 1 is a longitudinal sectional view of an upper half portion showing a first embodiment of a tapered roller bearing device of the present invention. FIG. 2 is a longitudinal sectional view of an upper half portion showing a second embodiment of the tapered roller bearing device of the present invention. FIG. 3 is a longitudinal sectional view of an upper half portion showing a third embodiment of the tapered roller bearing device of the present invention. FIG. 4 is a longitudinal sectional view showing a differential gear device as an example in which the tapered roller bearing device of the present invention is used.

Explanation of symbols

(1) Tapered roller bearing device
(2) Outer ring
(3) Inner ring
(4) Tapered rollers
(5) Cage
(6) (16) (26) Heat dissipation member
(10) Rotating shaft

Claims (2)

In the tapered roller bearing device that includes an outer ring, an inner ring, a plurality of tapered rollers disposed between the two rings, and a cage that holds these tapered rollers, and the inner ring is attached to the rotating shaft.
A tapered roller bearing device, further comprising a heat dissipating member made of a material that is in contact with both the large flange side end of the inner ring and the rotating shaft and has a higher thermal conductivity than the rotating shaft.   2. The tapered roller bearing device according to claim 1, wherein the heat dissipating member is made of an aluminum alloy or a magnesium alloy.

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