JP2014009764A - Lubrication structure for rotary shaft device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubrication structure for a rotary shaft device in which stirring resistance of lubricating oil is suppressed and a rolling bearing can be prevented from being seized.SOLUTION: An oil introduction space 63 is formed between a pair of rolling bearings 20, 30 and the oil introduction space 63 is communicated to an oil storage space 13 only through a gap between an outer ring 31 and an inner ring 32 of the rolling bearing 30 closer to an oil storage space 13 between the pair of rolling bearings 20, 30. In the inner circumference of the outer ring 31 of the rolling bearing 30 closer to the oil storage space 13 between the pair of rolling bearings 20, 30, a slope 31a for the outer ring which is inclined to an outer radial side, is formed from the oil introduction space 63 to the oil storage space 13. In the outer circumference of the inner ring 32 of the rolling bearing 30 closer to the oil storage space 13 between the pair of rolling bearings 20, 30, a slope 32a for the inner ring which is inclined to an outer radial side, is formed from the oil introduction space 63 to the oil storage space 13. In a housing 11, an oil supply passage 70 is provided of which one side is opened on a bottom face of the oil introduction space 63 and of which the other side is opened lower than the liquid level of lubricating oil in the oil storage space 13.

Description

  The present invention relates to a lubrication structure for a rotating shaft device that supplies lubricating oil stored in an oil sump space to a rolling bearing that rotatably supports a rotating shaft.

  As shown in FIG. 3, the differential apparatus 100 for an automobile scrapes the lubricating oil in the oil reservoir 102 provided in the differential case 101 with the ring gear 110, and feeds the scraped lubricating oil to the oil supply passage 103 of the differential case 101. Furthermore, it leads to a pair of tapered roller bearings 130 and 131 through the inlet 121 of the bearing case 120 and the oil introduction space 122.

JP 2008-115971 A

  The rotational speed of the ring gear 110 changes according to the vehicle speed. When the rotation speed of the ring gear 110 is high, the lubricating oil swept up by the ring gear 110 is scattered over a wide angular range, and when the rotation speed of the ring gear 110 is low, the lubricating oil swept up by the ring gear 110 is narrow in an angular range. Spatter over. In the angle range, there is a direction in which the largest amount is scattered, and the direction changes according to the rotation speed of the ring gear 110. When the direction in which the oil is scattered in a large amount matches the direction of the oil supply passage 103, more lubricating oil than necessary is supplied to the tapered roller bearings 130 and 131, and the stirring resistance increases. On the other hand, if the direction in which a large amount of splashes do not match the direction of the oil supply passage 103, the amount of lubricating oil supplied to the tapered roller bearings 130 and 131 becomes less than necessary, and seizure of the tapered roller bearings 130 and 131 occurs. Likely to happen.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a lubrication structure for a rotary shaft device that suppresses the stirring resistance of the lubricating oil and prevents seizure of the rolling bearing.

  According to the first aspect of the present invention, an oil sump space and a bearing space are formed inside the housing, a pair of rolling bearings is provided in the bearing space, and a rotary shaft is rotatable on the housing via the pair of rolling bearings. The bearing and the pair of rolling bearings include a ring-shaped outer ring, a ring-shaped inner ring disposed inside the outer ring, and a plurality of rolling elements that roll between the outer ring and the inner ring, In the lubricating structure of the rotary shaft device, in which the lubricating oil is stored in a part of the oil reservoir space, and the lubricating oil is supplied between the outer ring and the inner ring to lubricate the rolling bearing, the pair of rolling bearings Are spaced apart from each other in the axial direction of the rotary shaft, and an oil introduction space is formed between the pair of rolling bearings, and the oil introduction space is defined as the oil reservoir space of the pair of rolling bearings. The oil reservoir space is communicated only through the outer ring and the inner ring of the rolling bearing, and from the oil introduction space to the inner periphery of the outer ring of the rolling bearing on the oil reservoir space side of the pair of rolling bearings. An inclined surface for the outer ring inclined toward the outer diameter side toward the oil reservoir space is formed, and the oil reservoir space is formed from the oil introduction space to the outer periphery of the inner ring of the rolling bearing on the oil reservoir space side of the pair of rolling bearings. An oil supply passage that forms an inclined surface for an inner ring that is inclined toward the outer diameter toward the outer surface, one of which opens on the lower surface of the oil introduction space and the other of which opens below the liquid level of the lubricating oil in the oil reservoir space. Is provided in the housing, and the level of the lubricating oil injected into the oil sump space is set to be equal to or higher than the lowest position of the inclined surface for the outer ring.

  According to the first aspect, the lubricating oil in the oil reservoir space can be pumped up to the oil introduction space through the oil supply passage by the pumping action by the rotation of the inclined surface for the inner ring. As the number of rotations of the inclined surface for the inner ring increases, the amount of lubricating oil pumped up increases, so there is no need to supply lubricating oil more than necessary or there is no shortage of lubricating oil, reducing the stirring resistance of the lubricating oil and reducing the rolling bearings. Can prevent sticking.

  According to a second aspect of the present invention, the rolling bearing on the oil reservoir space side of the pair of rolling bearings is a tapered roller bearing using a tapered roller as the rolling element, and the inclined surface for the outer ring is the tapered surface. The outer ring raceway surface on which the roller rolls is formed, and the inner ring inclined surface is an inner ring raceway surface on which the tapered roller rolls.

  According to the second aspect, since the raceway surface for the inner ring is a straight surface inclined with respect to the axis of the inner ring, the lubricating oil flows smoothly, the stirring resistance of the lubricating oil is suppressed, and the seizure of the rolling bearing can be further prevented. .

  According to the present invention, the lubricating oil in the oil reservoir space can be pumped up to the oil introduction space through the oil supply passage by the pumping action by the rotation of the inclined surface for the inner ring. As the number of rotations of the inclined surface for the inner ring increases, the amount of lubricating oil pumped up increases, so there is no need to supply lubricating oil more than necessary or there is no shortage of lubricating oil, reducing the stirring resistance of the lubricating oil and reducing the rolling bearings. Can prevent sticking.

The longitudinal cross-sectional view of the differential apparatus in one Embodiment of this invention 1 is a partially enlarged longitudinal sectional view of FIG. 1 according to an embodiment of the present invention. Longitudinal sectional view of a conventional differential device

  An embodiment as an example of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a longitudinal sectional view of a differential device for an automobile, and FIG. 2 is a partially enlarged sectional view of FIG.

  In FIG. 1, a differential device 10 for an automobile includes a differential case 11, a ring gear 50 rotatably supported on the differential case 11, and a substantially cylindrical bearing case 60 provided integrally with the differential case 11. The pair of tapered roller bearings 20 and 30 held by the bearing case 60 and the pinion shaft 40 rotatably supported by the pair of tapered roller bearings 20 and 30 are provided. The rotation axis of the ring gear 50 and the rotation axis of the pinion shaft 40 cross each other three-dimensionally.

  The bearing case 60 is formed with a through hole 61 penetrating in the axial direction of the pinion shaft 40. The through hole 61 is formed in order from the ring gear 50 side, a second holding hole 62, an oil introduction space 63, a first holding hole. A hole 64 is provided. A second step 66 is provided between the second holding hole 62 and the oil introduction space 63, and a first step 67 is provided between the first holding hole 64 and the oil introduction space 63.

  The first tapered roller bearing 20 is fitted and held in the first holding hole 64 up to a position where it abuts on the first stepped portion 67. The first tapered roller bearing 20 includes the outer ring 21, the inner ring 22, and the tapered roller 23. Have The second tapered roller bearing 30 is fitted and held in the second holding hole 62 until it comes into contact with the second step portion 66. The second tapered roller bearing 30 includes an outer ring 31, an inner ring 32, and a tapered roller 33. Have

  An outer ring raceway surface 21 a on which the tapered roller 23 rolls is formed on the inner circumference of the outer ring 21, and an inner ring raceway surface 22 a on which the tapered roller 23 rolls is formed on the outer circumference of the inner ring 22. The outer ring raceway surface 21 a has a straight surface inclined with respect to the axis of the inner ring 22, and the inner ring raceway surface 22 a has a straight surface inclined with respect to the axis of the inner ring 22. The inclination angle of the inner ring 22 with respect to the axis is larger on the outer ring raceway surface 21a than on the inner ring raceway surface 22a.

  An outer ring raceway surface 31 a on which the tapered roller 33 rolls is formed on the inner circumference of the outer ring 31, and an inner ring raceway surface 32 a on which the tapered roller 33 rolls is formed on the outer circumference of the inner ring 32. The outer ring raceway surface 31 a has a straight surface inclined with respect to the axis of the inner ring 32, and the inner ring raceway surface 32 a has a straight surface inclined with respect to the axis of the inner ring 32. The inclination angle of the inner ring 32 with respect to the axis is larger on the outer ring raceway surface 31a than on the inner ring raceway surface 32a.

  The first tapered roller bearing 20 is arranged so that the small diameter side of the inner ring 22 is on the oil introduction space 63 side, and the second tapered roller bearing 30 is arranged so that the small diameter side of the inner ring 32 is on the oil introduction space 63 side. Has been.

  A pinion 41 that meshes with the ring gear 50 is formed at one end of the pinion shaft 40 on the ring gear 50 side, and a flange joint 42 is fixed to the other end of the pinion shaft 40 via a nut 43. A spacer 51 is fitted between the inner ring 22 and the inner ring 32 on the outer periphery of the pinion shaft 40. A step 44 of the pinion shaft 40 abuts on the end surface of the inner ring 32 on the ring gear 50 side, and a spacer 51 abuts on an end surface of the inner rings 22, 32 on the oil introduction space 63 side, opposite to the ring gear 50 of the inner ring 22. A flange joint 42 is brought into contact with the end face of the shaft, and the preload applied to the pair of tapered roller bearings 20, 30 can be adjusted by tightening the nut 43. An oil seal 52 is fitted and fixed in the first holding hole 64, and the lip of the oil seal 52 is in sliding contact with the outer periphery of the flange joint 42.

  A working space 12 in which the ring gear 50 and the pinion 41 rotate is provided inside the differential case 11, and a first oil sump 13 for storing lubricating oil is provided below the working space 12. Below the oil introduction space 63, a second oil reservoir 69 for storing lubricating oil is provided.

  The bearing case 60 is formed with an oil supply passage 70 having one end opened on the side surface of the first oil sump 13 and the other end opened on the lower surface of the second oil sump 69. The bearing case 60 is formed with an oil discharge passage 71 having one end opened on the side surface of the first oil reservoir 13 and the other end opened on the lower surface of the first holding hole 64.

  The differential device 10 is installed in a state where the pinion shaft 40 is inclined with respect to the horizontal axis, that is, in a state where the tapered roller bearing 20 is lifted with respect to the tapered roller bearing 30. The outer ring raceway surface 31a has the lowest angular position in the circumferential direction, and has the lowest position in the axial direction at this lower angular position. Lubricating oil is injected into the first oil reservoir 13 up to a position exceeding the lowest position (FIG. 2). The outer ring raceway surface 31a has the lowest angular position in the circumferential direction, and has the highest position in the axial direction at this lower angular position. Lubricating oil is injected into the first oil sump 13 up to a position that does not reach the highest position. In this way, the lubricating oil can be sent from the oil introduction space 63 to the first oil reservoir 13 through the space between the outer ring 31 and the inner ring 32 by the pumping action of the outer ring raceway surface 31a. The stirring resistance can be reduced.

  Although the agitation resistance of the lubricating oil is increased, the lubricating oil may be injected up to the position described below where the pumping function functions. The outer ring raceway surface 31a has the highest angular position in the circumferential direction, and has the lowest position in the axial direction at this high angular position. It is also possible to inject the lubricating oil into the first oil reservoir 13 up to a position that does not reach the lowest position, that is, a position that does not block the space between the outer ring raceway surface 31a and the inner ring raceway surface 32a.

  The outer ring raceway surface 31a has the lowest angular position in the circumferential direction, and has the highest position in the axial direction at this lower angular position. The outer ring raceway surface 21a has the lowest angular position in the circumferential direction, and has the highest position in the axial direction at this lower angular position. In a state where the pinion shaft 40 is inclined with respect to the horizontal axis, the highest axial position at the lowest angular position of the outer ring raceway surface 31a is the highest axial position at the lowest angular position of the outer ring raceway surface 21a. A pair of tapered roller bearings 20 and 30 are selected so as to be equal. In this way, the lubricating oil level of the second oil reservoir 69 is the highest in the axial direction at the lowest angular position of the outer ring raceway surface 31a and the axial direction at the lowest angular position of the outer raceway raceway surface 21a. Matches the highest position of.

  Next, the operation will be described based on the above-described configuration.

  The differential device 10 is installed in a state where the pinion shaft 40 is inclined with respect to the horizontal axis, that is, in a state where the tapered roller bearing 20 is lifted with respect to the tapered roller bearing 30. Lubricating oil is injected into the first oil reservoir 13 such that the liquid level comes within the range from the lowest position in the axial direction to the highest position at the lowest angular position in the circumferential direction of the outer ring raceway surface 31a. .

  When the pinion shaft 40 rotates in this state, the ring gear 50 meshing with the pinion shaft 40 rotates. A part of the ring gear 50 is immersed in the lubricating oil in the first oil reservoir 13, and the lubricating oil is interposed between the ring gear 50 and the pinion 41, so that the meshing between the ring gear 50 and the pinion 41 becomes smooth.

  The inner rings 22 and 32 rotate together with the pinion shaft 40, the air is rotated by the inner ring raceway surfaces 22a and 32a, and the air in the oil introduction space 63 is discharged, whereby the pressure in the oil introduction space 63 is changed to the working space. It becomes low compared with the pressure in 12. As a result, the lubricating oil in the first oil sump 13 flows into the second oil sump 69 via the oil supply passage 70, one is returned to the working space 12 through the outer ring 31 and the inner ring 32, and the other is The outer ring 21 and the inner ring 22 are returned to the working space 12 through the oil discharge passage 71.

  Thus, the lubricating oil is supplied to the outer ring raceway surfaces 21a and 31a, and the lubricating oil is supplied to the inner ring raceway surfaces 22a and 32a via the tapered rollers 23 and 33. Wear of the outer ring raceway surfaces 21a and 31a and the inner ring raceway surfaces 22a and 32a due to rolling of the tapered rollers 23 and 33 can be reduced, and temperature rise can be suppressed.

  Since the pump action is caused by the air being driven by the inner ring raceway surfaces 22a and 32a, the lubricating oil does not increase more than necessary, and the stirring resistance of the lubricating oil can be reduced. Further, it is possible to secure more lubricating oil than necessary and prevent seizure of the raceway surface. Since the inner ring raceway surfaces 22a and 32a are straight surfaces inclined with respect to the axes of the inner rings 22 and 32, the lubricating oil flows smoothly, and seizure of the raceway surface can be further prevented.

  The present invention is not limited to these embodiments, and can of course be implemented in various modes without departing from the gist of the present invention.

  In the embodiment described above, an example in which tapered roller bearings are used as the rolling bearings 20 and 30 has been described. As another embodiment, angular ball bearings may be used as the rolling bearings 20 and 30.

  In the above-described embodiment, the example in which the differential device is applied as the rotating shaft device has been described. As another embodiment, a spindle device of a machine tool may be applied as the rotary shaft device.

  11: differential case (housing), 13: first oil sump (oil sump space), 20: first tapered roller bearing (rolling bearing), 21: outer ring, 21a: raceway surface for outer ring (inclined surface for outer ring) 22: Inner ring, 22a: Inner ring raceway surface (inner ring inclined surface), 23: Tapered roller (rolling element), 30: Second tapered roller bearing (rolling bearing), 31: Outer ring, 31a: Outer ring raceway surface (Inclined surface for outer ring), 32: inner ring, 32a: raceway surface for inner ring (inclined surface for inner ring), 33: tapered roller (rolling element), 50: ring gear, 40: pinion shaft, 41: pinion, 60: bearing case (Housing), 61: through hole (bearing space), 63: oil introduction space, 68: introduction port, 69: second oil reservoir, 70: oil supply passage, 71: oil discharge passage

Claims (2)

An oil sump space and a bearing space are formed inside the housing, a pair of rolling bearings is provided in the bearing space, and a rotary shaft is rotatably supported on the housing via the pair of rolling bearings. The pair of rolling bearings A ring-shaped outer ring, a ring-shaped inner ring disposed inside the outer ring, and a plurality of rolling elements that roll between the outer ring and the inner ring. In the lubricating structure of the rotary shaft device that lubricates the rolling bearing by supplying the lubricating oil between the outer ring and the inner ring,
The pair of rolling bearings are spaced apart from each other in the axial direction of the rotary shaft, and an oil introduction space is formed between the pair of rolling bearings. The oil introduction space is formed as the oil reservoir in the pair of rolling bearings. The oil introduction space is communicated with the oil sump space only through the space between the outer ring and the inner ring of the rolling bearing on the space side, and the oil introduction space is provided on the inner periphery of the outer ring of the rolling bearing on the oil sump space side of the pair of rolling bearings. An outer ring inclined surface inclined toward the oil reservoir space from the oil introduction space to the outer periphery of the inner ring of the rolling bearing on the oil reservoir space side of the pair of rolling bearings. An oil that forms an inclined surface for an inner ring that is inclined toward the outer diameter side toward the reservoir space, one opening on the lower surface of the oil introduction space, and the other opening below the liquid level of the lubricating oil in the oil reservoir space. Serving Lubricating structure for rotary shaft device is provided a passage in said housing, characterized in that the liquid level of the lubricating oil injected into the oil reservoir space, and above the lowest position of the inclined surface for the outer ring. Of the pair of rolling bearings, the rolling bearing on the oil reservoir space side is a tapered roller bearing using a tapered roller as the rolling element, and the outer ring inclined surface is an outer ring raceway surface on which the tapered roller rolls. The lubricating structure for a rotary shaft device according to claim 1, wherein the inclined surface for the inner ring is a raceway surface for the inner ring on which the tapered roller rolls.

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