JP2017155784A - Lubrication structure of bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubrication structure of a bearing which can make a bearing lubricant by oil without immersing the bearing into the oil.SOLUTION: A drive pinion shaft 2 is held at two pieces of bearings 21 which are interposed between the drive pinion shaft 2 and an internal peripheral face of an insertion part 12. A space 22 sandwiched by the two pieces of the bearings 21 is formed between the drive pinion shaft 2 and the internal peripheral face of the insertion part 12. A spacer 28 which rotates together with an inner race 25 is interposed between the two pieces of the bearings 21 and each inner race 25, and a plurality of blades 31 extending to a rotation radial direction are arranged at an external peripheral face of the spacer 28. A suction pipe 14 is inserted into a position being a lower end of the insertion part 12. Oil is accumulated at a bottom of a unit case 4, and a lower end of the suction pipe 14 is immersed in the oil sump.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bearing lubrication structure in a power transmission unit such as a transmission or a differential gear that transmits power from a drive source.

  In vehicles such as automobiles, power from a drive source is input to a transmission (transmission), and power shifted by the transmission is transmitted to drive wheels via a differential gear (differential device) or the like.

  FIG. 2 is a cross-sectional view showing a configuration in the vicinity of the drive pinion shaft 102 that inputs power to the differential gear Assy 101.

  The differential gear assembly 101 and the drive pinion shaft 102 are accommodated in the unit case 103.

  The differential gear Assy 101 includes a differential case 104. The differential case 104 is rotatably held by the unit case 103. The differential case 104 is formed with a flange portion extending radially from the outer periphery of the differential case 104, and a ring gear 105 formed of a bevel gear is fixed to the flange portion so as not to be relatively rotatable.

  The drive pinion shaft 102 is rotatably held by the unit case 103 via two tapered roller bearings (tapered roller bearings) 106 and 107. The drive pinion shaft 102 is disposed at a position offset downward with respect to a straight line extending in the axial direction of the drive pinion shaft 102 through the center of the ring gear 105 (the center of the differential case 104). A drive pinion gear 108 formed of a bevel gear is provided at the end of the drive pinion shaft 102 on the differential gear Assy 101 side. Drive pinion gear 108 meshes with ring gear 105.

  When the drive pinion shaft 102 rotates, the rotation is transmitted from the drive pinion gear 108 to the ring gear 105, and the ring gear 105 and the differential case 104 rotate.

  In the unit case 103, oil (lubricating oil) for lubricating each part is enclosed. An oil reservoir is generated at the bottom of the unit case 103. The amount of oil in the unit case 103 is set so that, for example, the oil level of the oil reservoir is at a position indicated by a two-dot chain line in FIG. 2 when the differential gear Assy 101 is stationary. Thereby, a part of taper roller bearing 106,107 can be immersed in an oil reservoir, and the occurrence of seizure of taper roller bearing 106,107 can be suppressed.

JP2013-122260A

  However, in the structure in which the drive pinion shaft 102 is disposed above the center axis of the differential gear Assy 101, when the taper roller bearings 106 and 107 are lubricated with oil, it is necessary to increase the oil level (oil amount). If the amount of oil in the unit case 103 is large, the rotational resistance (stirring resistance) of the differential case 104 and the ring gear 105 due to oil increases, and there is a concern about an increase in mechanical loss.

  An object of the present invention is to provide a lubrication structure for a bearing in which the bearing can be lubricated with oil without immersing the bearing in oil.

  To achieve the above object, a bearing lubrication structure according to the present invention includes a rotating body and two bearings that rotatably hold the rotating body, and transmits a power through the rotating body. In this lubricating structure, an insertion portion through which the rotating body is inserted is formed, and the two bearings are disposed between the rotating body and the inner peripheral surface of the insertion portion. A space interposed between the two bearings is formed between the rotating body and the inner peripheral surface of the insertion portion, and a negative pressure generated in the space as the rotating body rotates, A suction path for sucking oil stored in the space into the space is formed.

  According to this configuration, the rotating body is inserted into the insertion portion and is rotatably held by the two bearings interposed between the rotating body and the inner peripheral surface of the insertion portion. A space sandwiched between two bearings is formed between the rotating body and the inner peripheral surface of the insertion portion. When the rotating body rotates, negative pressure is generated in the space between the two bearings, and the oil stored in the power transmission unit is sucked up into the space between the two bearings through the suction path due to the negative pressure. . Therefore, the oil can be satisfactorily flowed into the space between the two bearings, and the inflowed oil can be supplied to the two bearings.

  Therefore, the two bearings can be lubricated with oil without immersing the bearings in oil, and the occurrence of seizure due to insufficient lubrication of the two bearings can be suppressed. As a result, it is possible to reduce the amount of oil in the power transmission unit, and it is possible to reduce the rotational resistance (stirring resistance) received from the oil by the scraping portion and other members that rotate as the rotating body rotates. . By reducing the stirring resistance, the mechanical loss in the power transmission unit is reduced, and the traveling fuel consumption of the vehicle equipped with the power transmission unit can be improved.

  The individual bearings may be tapered roller bearings having rollers (rollers) that are inclined away from the rotation axis of the rotating body toward the outside with respect to the space between the two bearings.

  Thereby, a negative pressure can be generated in the space between the two bearings as the rotating body rotates.

  A spacer that rotates integrally with the inner race may be interposed between the inner races of the two bearings, and a blade that extends in the rotational radial direction may be provided on the outer peripheral surface of the spacer.

  With the rotation of the rotating body, the spacer provided with the blades rotates, so that a negative pressure can be generated in the space between the two bearings. As a result, the negative pressure can be increased in the space between the two bearings, and the oil can be sucked up well into the space between the two bearings. Therefore, the two bearings can be further lubricated with oil, and the occurrence of seizure due to insufficient lubrication of the two bearings can be further suppressed.

  According to the present invention, the bearing can be lubricated with oil without immersing the bearing in oil. Therefore, the reduction in the amount of oil in the power transmission unit can reduce the mechanical loss in the power transmission unit, and as a result, the traveling fuel consumption of the vehicle on which the power transmission unit is mounted can be improved.

It is sectional drawing which shows the structure of the power transmission unit 1 which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure of the conventional power transmission unit.

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

<Configuration of power transmission unit>
FIG. 1 is a cross-sectional view showing a configuration of a power transmission unit 1 according to an embodiment of the present invention.

  The power transmission unit 1 includes a drive pinion shaft 2 and a differential gear Assy 3 and is a unit for transmitting power output from a transmission (not shown) to a drive shaft (not shown).

  The drive pinion shaft 2 and the differential gear Assy 3 are accommodated in the unit case 4. The unit case 4 is, for example, an aluminum casting that is cast by die casting. The unit case 4 is formed with an outer wall portion 11 that forms an outer shell of the power transmission unit 1 and a cylindrical insertion portion 12 that is positioned inside the outer wall portion 11 and through which the drive pinion shaft 2 can be inserted. A through hole 13 is formed in the insertion portion 12 at a position that is a lower end of the insertion portion 12 so as to penetrate in the vertical direction. A suction pipe 14 is inserted into the through hole 13.

  The unit case 4 contains oil (lubricating oil) for lubricating each part. An oil reservoir is generated at the bottom of the unit case 4. The amount of oil in the unit case 4 is, for example, in the state where the drive pinion shaft 2 is stationary, for example, the position where the oil level of the oil sump is indicated by the two-dot chain line in FIG. 1, that is, the differential gear assembly 3 It is set so as to be located at a position substantially the same as the lower end of the side gear (not shown). The suction pipe 14 extends into the accumulated oil, and the lower end of the suction pipe 14 is disposed at a position where the suction pipe 14 is always immersed in the oil even during operation.

  The drive pinion shaft 2 is inserted through the insertion portion 12. Two bearings 21 are interposed between the drive pinion shaft 2 and the inner peripheral surface of the insertion portion 12. The two bearings 21 are arranged at an interval in the rotation axis direction of the drive pinion shaft 2. Thus, a space 22 sandwiched between the two bearings 21 is formed between the drive pinion shaft 2 and the inner peripheral surface of the insertion portion 12.

  As the bearing 21, a tapered roller bearing (tapered roller bearing) is employed. The inner race 25 of the bearing 21 is externally fitted to the drive pinion shaft 2 and is fixed to the drive pinion shaft 2. The outer race 26 of the bearing 21 is fitted into the insertion portion 12 and is fixed to the insertion portion 12. A plurality of rollers (conical rollers) 27 are interposed between the inner race 25 and the outer race 26, and the bearings 21 move away from the rotation axis of the drive pinion shaft 2 toward the outside of the space 22. It is provided in the direction which inclines. Further, spacers 28 are interposed between the inner races 25 of the two bearings 21, and the spacers 28 are fixed to the inner races 25.

  A plurality of blades 31 are provided on the outer peripheral surface of the spacer 28. The blades 31 extend in the radial direction from the outer peripheral surface of the spacer 28, extend in the rotational axis direction, and are formed in a substantially V shape that is pointed toward the downstream side in the rotational direction of the drive pinion shaft 2 at the center in the rotational axis direction. Has been.

  A drive pinion gear 41 formed of a bevel gear is provided at the end of the drive pinion shaft 2 on the differential gear Assy3 side. The drive pinion gear 41 is disposed at a position above the center of the differential case 51 described below, and the drive pinion shaft 2 is offset upward with respect to a straight line extending in the axial direction of the drive pinion shaft 2 through the center of the differential case 51. It is arranged at the position.

  The differential gear Assy 3 includes a differential case 51. The differential case 51 is held in the unit case 4 so as to be rotatable about a rotation axis perpendicular to the rotation axis direction of the drive pinion shaft 2. The differential case 51 is formed with a flange portion 52 that projects radially from the outer periphery thereof. The flange portion 52 is provided with a ring gear (not shown) formed of a bevel gear so as not to be relatively rotatable. The drive pinion gear 41 is engaged with the ring gear.

<Effect>
According to the above configuration, when the drive pinion shaft 2 is rotated by the power output from the transmission, the rotation is transmitted from the drive pinion gear 41 to the ring gear, and the differential case 51 of the differential gear Assy3 rotates integrally with the ring gear. The rotation of the differential case 51 is transmitted to the drive shaft via a differential pinion shaft, a differential pinion gear, and a differential side gear (all not shown) provided in the differential gear Assy3. As a result, the power output from the transmission is transmitted to the drive shaft, and the power is transmitted from the drive shaft to the drive wheels of the vehicle on which the power transmission unit 1 is mounted.

  The drive pinion shaft 2 is inserted into the insertion portion 12 and is rotatably held by two bearings 21 interposed between the drive pinion shaft 2 and the inner peripheral surface of the insertion portion 12. A space 22 sandwiched between two bearings 21 is formed between the drive pinion shaft 2 and the inner peripheral surface of the insertion portion 12.

  The bearing 21 is a taper roller bearing in which the roller 27 is inclined so as to be away from the rotation axis of the drive pinion shaft 2 toward the outside with respect to the space 22 between the drive pinion shaft 2 and the inner peripheral surface of the insertion portion 12. Is provided. Thus, as the drive pinion shaft 2 rotates, air is discharged from the space 22 sandwiched between the two bearings 21 through the space between the inner race 25 and the outer race 26 of the bearing 21 by the action of centrifugal force. A negative pressure can be generated.

  A spacer 28 that rotates integrally with the inner race 25 is interposed between the inner races 25 of the two bearings 21, and a plurality of blades 31 that extend in the rotational radial direction are provided on the outer peripheral surface of the spacer 28. It has been. Therefore, a negative pressure can be generated on the downstream side in the rotation direction of each blade 31 by rotating the spacer 28 provided with the blade 31 along with the rotation of the drive pinion shaft 2. As a result, the negative pressure near the upper end of the suction pipe 14 can be increased.

  A through hole 13 is formed at the lower end of the insertion portion 12, and a suction pipe 14 is inserted through the through hole 13. Oil is collected at the bottom of the unit case 4, and the lower end of the suction pipe 14 is immersed in the oil reservoir. Therefore, when a negative pressure is generated in the space 22 sandwiched between the two bearings 21 as the drive pinion shaft 2 rotates, the oil stored in the unit case 4 passes through the suction pipe 14 due to the negative pressure. Sucked into the space 22. Therefore, oil can be satisfactorily flowed into the space 22, and the inflowed oil can be supplied to the two bearings 21.

  Therefore, the two bearings 21 can be lubricated with oil without immersing the bearings 21 in oil, and the occurrence of seizure due to insufficient lubrication of the two bearings 21 can be suppressed. As a result, the amount of oil in the unit case 4 can be reduced, and the rotational resistance (stirring resistance) received from the oil by the differential case 51 rotating with the rotation of the drive pinion shaft 2 can be reduced. By reducing the stirring resistance, the mechanical loss in the power transmission unit 1 is reduced, and the traveling fuel consumption of the vehicle on which the power transmission unit 1 is mounted can be improved.

<Modification>
As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form.

  For example, the drive pinion shaft 2 may be an output shaft of a transmission, or may be a transfer rotating shaft to which power from the output shaft is transmitted.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

1 Power transmission unit 2 Drive pinion shaft (rotating body)
12 Insertion part 14 Suction pipe (suction path)
21 Bearing 22 Space

Claims (1)

In a power transmission unit that includes a rotating body and two bearings that rotatably hold the rotating body, and transmits power through the rotating body.
An insertion part through which the rotating body is inserted is formed,
The two bearings are interposed between the rotating body and the inner peripheral surface of the insertion portion,
A space sandwiched between the two bearings is formed between the rotating body and the inner peripheral surface of the insertion portion,
A bearing lubrication structure in which a suction path for sucking up oil stored in the power transmission unit into the space is formed by negative pressure generated in the space as the rotating body rotates.

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