JP2017155787A - 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: Oil is accumulated at a bottom of a unit case 4, and a part of a first flange member 31 and a part of a second flange member 35 are immersed in the oil sump. Therefore, when the first flange member 31 and the second false member 35 rotate accompanied by the rotation of a drive pinion shaft 2, the oil accumulated at the bottom of the unit case 4 is scooped up by the first flange member 31 and the second flange member 35. The scooped-up oil is scattered into an oil receiving chamber 14A between an outer wall part 11 and the insertion part 12. The oil receiving chamber 14A communicates with a space 22 which is sandwiched by two pieces of bearings 21 between the drive pinion shaft 2 and the insertion part 12 via a first communication route 23 which penetrates the insertion part 12.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. 3 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 that projects radially from the outer periphery thereof, and a ring gear 105 formed of a bevel gear is provided on 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 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. 3 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, if the amount of oil in the unit case 103 is large, the rotational resistance (stirring resistance) that the differential case 104 and the ring gear 105 receive from the 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 lubrication structure, there is provided a scraping section that rotates with the rotation of the rotating body and scrapes up the oil stored in the power transmission unit. An oil receiving part for receiving the oil scooped up by the scooping part is formed above the body, and an oil passage for supplying the oil received by the oil receiving part to at least one of the two bearings is formed. Yes.

  According to this configuration, the scraping part rotates as the rotating body rotates, and the oil stored in the power transmission unit is scraped up by the scraping part. The oil scooped up is received by an oil receiving part formed above the rotating body. And the oil received by the oil receiving part is supplied to at least one of the two bearings through the oil passage. Therefore, the bearing can be lubricated with oil without immersing the bearing in oil, and the occurrence of seizure due to insufficient lubrication of the bearing 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.

  A space in which two bearings are interposed between the rotating body and the inner peripheral surface of the insertion portion through which the rotating body is inserted, and sandwiched between the two bearings between the rotating body and the inner peripheral surface of the shaft insertion portion. The oil passage is formed so as to communicate the space and the oil receiving portion, and the individual bearings are rollers (rollers) inclined so as to move away from the rotation axis of the rotating body toward the outside with respect to the space. It is preferable that the taper roller bearing has.

  In this configuration, when the rotating body rotates, a negative pressure is generated in the space between the two bearings, and the negative pressure causes the oil received in the oil receiving portion to enter the space between the two bearings through the oil passage. Inhaled. Therefore, oil can be made to actively flow into the space between the two bearings, and the oil that has flowed in can be supplied to 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 which concerns on one Embodiment of this invention. It is the figure which looked at the power transmission unit from the one side of the rotating shaft direction. 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. FIG. 2 is a view of the power transmission unit 1 viewed from one side (power input side) in the rotation axis direction.

  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 includes an outer wall portion 11 that forms an outer shell of the power transmission unit 1, a cylindrical insertion portion 12 that is located inside the outer wall portion 11 and can be inserted through the drive pinion shaft 2, and the outer wall portion 11. A plurality of partition wall portions 13 extending between the portion 12 and extending radially around the insertion portion 12 are formed. Thereby, between the outer wall part 11 and the insertion part 12 is divided by the partition wall part 13, and between the outer wall part 11 and the insertion part 12, as shown in FIG. The same number of spaces 14 are formed around the insertion portion 12.

  Two spaces 14 </ b> A and 14 </ b> B of the plurality of spaces 14 are located above the insertion portion 12. The spaces 14A and 14B are adjacent to each other with the partition wall 13 interposed therebetween, and one space 14A is located upstream of the other space 14B in the rotational direction of the drive pinion shaft 2.

  The drive pinion shaft 2 is inserted through the insertion portion 12. As shown in FIG. 1, 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.

  A first communication passage 23 that communicates the space 14 </ b> A and the space 22 is formed in the insertion portion 12 so as to penetrate in the rotational radial direction. Further, the insertion portion 12 is formed with a second communication passage 24 that communicates the space 14B and the space 22 so as to penetrate in the rotational radial direction.

  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 first flange member 31 is fitted on the end portion of the drive pinion shaft 2 on the transmission side. The first flange member 31 is integrally formed with an outer fitting portion 32 that is fitted on the drive pinion shaft 2 and a flange portion 33 that protrudes outwardly from the transmission-side end portion of the outer fitting portion 32. Has been. The outer fitting portion 32 of the first flange member 31 is fitted on the drive pinion shaft 2, and the nut 34 is screwed onto the drive pinion shaft 2 protruding from the outer fitting portion 32, whereby the first flange member 31 is driven. The pinion shaft 2 is fixedly attached.

  A second flange member 35 is provided on the transmission side with respect to the first flange member 31. The second flange member 35 is attached to a rotary shaft 36 that is rotated by the power output from the transmission, and has a cylindrical portion 37 and a cylindrical portion 37 on the first flange member 31 side. And a flange portion 38 projecting in a shape. The flange portion 38 is in surface contact with the flange portion 33 of the first flange member 31. The flange portions 33 and 38 are fixed to each other by a bolt 39 that passes through them.

  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.

  A breather 5 for releasing the pressure in the unit case 4 to the atmosphere is provided on the upper part of the unit case 4. As shown in FIG. 2, the breather 5 is inserted from the outside of the unit case 4 into a through hole 61 that penetrates the outer wall portion 11 of the unit case 4. The breather 5 communicates a breather chamber (hereinafter, referred to as “breather chamber 14 </ b> B”) formed of a space 14 </ b> B between the outer wall portion 11 and the insertion portion 12 and the outside of the unit case 4.

  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. For example, when the drive pinion shaft 2 is stationary, the oil amount in the unit case 4 is provided, for example, at the position where the oil level of the oil reservoir is indicated by a two-dot chain line in FIGS. 1 and 2, that is, the differential gear Assy 3. The differential side gear (not shown) is set so as to be positioned at substantially the same height as the lower end.

<Effect>
According to the above configuration, when the rotating shaft 36 is rotated by the power output from the transmission, the rotation is transmitted to the drive pinion shaft 2 via the first flange member 31 and the second flange member 35. The drive pinion shaft 2 rotates. When the drive pinion shaft 2 rotates, 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.

  Oil is collected at the bottom of the unit case 4, and a part of the first flange member 31 and the second flange member 35 are immersed in the oil reservoir. Therefore, when the first flange member 31 and the second flange member 35 rotate with the rotation of the drive pinion shaft 2, the first flange member 31 and the second flange member 35 accumulate at the bottom of the unit case 4. Oil is raked up.

  The scooped up oil jumps into the space 14 </ b> A between the outer wall portion 11 and the insertion portion 12. This space 14A functions as an oil receiving chamber (hereinafter referred to as “oil receiving chamber 14A”) that receives oil scooped up from the bottom of the unit case 4, and the oil that has entered the oil receiving chamber 14A 14A is stored.

  The oil receiving chamber 14 </ b> A communicates with the space 22 sandwiched between the two bearings 21 between the drive pinion shaft 2 and the inner peripheral surface of the insertion portion 12 via the first communication passage 23 that penetrates the insertion portion 12. ing. Therefore, the oil accumulated in the oil receiving chamber 14 </ b> A flows into the space 22 between the drive pinion shaft 2 and the inner peripheral surface of the insertion portion 12 through the first communication path 23, and the space 22 rotates the drive pinion shaft 2. It is supplied to two bearings 21 sandwiched from both sides in the axial direction.

  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 first flange member 31 and the second flange member 35 that rotate with the rotation of the drive pinion shaft 2 and other members (such as the differential case 51) The rotational resistance (stirring resistance) received from oil 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.

  The bearing 21 is a taper roller bearing, and the roller 27 is inclined so as to move 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. It is provided in the direction to do. Thereby, as the drive pinion shaft 2 rotates, oil and air are discharged from the space 22 sandwiched between the two bearings 21 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 in the space 22. Due to this negative pressure, the oil received in the oil receiving chamber 14 </ b> A is sucked into the space 22 sandwiched between the two bearings 21 through the first communication passage 23. Therefore, oil can be made to actively flow into the space 22 sandwiched between the two bearings 21, and the introduced oil can be supplied to the two bearings 21. Therefore, the two bearings 21 can be further lubricated with oil, and the occurrence of seizure due to insufficient lubrication of the two bearings 21 can be further suppressed.

  Further, a breather chamber 14B is formed above the insertion portion 12. The breather chamber 14 </ b> B communicates with the outside of the unit case 4 via a breather 5 attached to the unit case 4. Further, the breather chamber 14B has a space 22 sandwiched between the two bearings 21 between the drive pinion shaft 2 and the inner peripheral surface of the insertion portion 12 via the second communication path 24 formed in the insertion portion 12. Communicate. Therefore, the oil that has entered the breather chamber 14 </ b> B can be discharged to the space 22 through the second communication path 24. As a result, the amount of oil in the breather chamber 14B can be reduced, and the ejection of oil from the breather 5 can be suppressed.

  Further, since oil is also supplied to the space 22 from the breather chamber 14B, the two bearings 21 can be made to be in a better lubrication state by the oil, and the occurrence of seizure due to insufficient lubrication of the two bearings 21 is further increased. Can be suppressed.

<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)
14A Oil receiving chamber (oil receiving part)
21 Bearing 23 First communication passage (oil passage)
31 First flange member (scraping part)
35 Second flange member (scraping part)

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.
Rotating with the rotation of the rotating body, provided with a scooping section that scoops up the oil stored in the power transmission unit,
Above the rotating body, an oil receiving portion for receiving the oil scraped up by the scraping portion is formed,
A bearing lubrication structure in which an oil passage for supplying oil received in the oil receiving portion to at least one of the two bearings is formed.

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