JP2015224654A - Differential gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply a sufficient amount of lubricant to a slide contact portion of a pinion gear and a pinion shaft, in a differential gear of a structure including a cylindrical projecting portion substantially closing an inner opening edge of a shaft insertion hole of a pinon gear, on the pinion shaft.SOLUTION: In a differential gear including a differential case 30, a side gear 42 disposed coaxially with a rotating shaft O1 of the differential case 30, a pinion gear 41 orthogonally engaged with the side gear 42, and a pinion shaft 43 inserted into a shaft insertion hole 38 of the pinion gear 41 and fitted to the differential case 30, the pinion shaft 43 has a through hole 24 penetrating in a direction of the rotating shaft O1, and including a cylindrical projecting portion 45 projecting from a peripheral face of the pinion shaft 43 and substantially closing an inner opening edge 38A of the shaft insertion hole 38. A lubricant supply hole 3 one end of which faces a hole inner face of the through hole 24, and the other end of which faces the inner opening edge 38A of the shaft insertion hole 38, is formed on the cylindrical projecting portion 45.

Description

  The present invention relates to a differential device.

  An automobile final reduction device is generally a device that decelerates again the power generated by the prime mover, decelerated by the transmission and transmitted through the propulsion shaft, and distributes it to the left and right rear wheels. The final reduction gear is composed of a drive pinion gear that rotates integrally with the propulsion shaft, a ring gear that meshes with the drive pinion gear at a right angle, a differential that rotates integrally with the ring gear, a housing that accommodates these devices, and the like. .

  The differential device includes a differential case that rotates integrally with the ring gear, a side gear that is disposed inside the differential case and rotates integrally with the drive shaft (drive shaft), a pinion gear that meshes with the side gear and is disposed inside the differential case, and a pinion gear It is comprised from the pinion shaft etc. which are inserted in the shaft insertion hole of this, and are fitted to a differential case.

  When a rotation difference occurs between the left and right rear wheels, the pinion gear rotates with respect to the pinion shaft, thereby corresponding to the rotation difference. Therefore, a slight gap is formed in the sliding contact portion formed between the inner surface of the shaft insertion hole of the pinion gear and the outer peripheral surface of the pinion shaft. In general, in order to prevent seizure of the sliding contact portion, the lubricating oil in the differential case flows outward by centrifugal force, so that the lubricating oil flows from the opening of the pinion gear hole facing the inner center of the differential case. It flows in and is supplied to the sliding contact portion.

As a technique for improving the lubricity of the sliding contact portion, Patent Document 1 describes a technique in which a spiral groove is provided in a pinion shaft and lubricating oil is supplied to the sliding contact portion through the spiral groove.
On the other hand, Patent Document 2 describes a structure in which a relatively large joint member protruding from the peripheral surface of the pinion shaft is provided at a substantially central portion in the axial direction of the pinion shaft.

JP 2007-51668 A JP-A-10-159940

  According to the structure described in Patent Document 2, the joint member is formed so as to protrude from the peripheral surface of the pinion shaft, so that the joint member is positioned so as to substantially block the inner opening edge of the shaft insertion hole. Therefore, the lube lubricating oil supplied to the sliding contact portion along the surface of the pinion shaft is blocked by the joint member, and there is a possibility that a predetermined amount of lubricating oil supplied to the sliding contact portion cannot be secured.

  The present invention was created to solve such problems, and in a structure in which a pinion shaft is provided with a cylindrical protrusion that substantially closes the inner opening edge of the shaft insertion hole of the pinion gear, the pinion gear and the pinion shaft An object of the present invention is to provide a differential device capable of supplying a sufficient amount of lubricating oil to the sliding contact portion.

  In order to solve the above problems, the present invention provides a differential case, a side gear disposed coaxially with the rotation shaft of the differential case, a pinion gear that is orthogonally engaged with the side gear, and a shaft insertion hole of the pinion gear to be inserted into the differential case. In the differential including the pinion shaft to be fitted, the pinion shaft is formed with a through hole along the rotation axis direction, and protrudes in a radially outward direction of the pinion shaft from the peripheral surface of the pinion shaft. Lubricating oil supply hole provided with a cylindrical protrusion that substantially closes the inner opening edge of the shaft insertion hole, one end facing the inner surface of the through hole and the other end facing the inner opening edge of the shaft insertion hole Is formed.

  According to this differential device, when the differential case rotates, a part of the lubricating oil in the differential case enters the inside of the through hole of the cylindrical protrusion. Lubricating oil adhering to the inner surface of the through hole flows through the lubricating oil supply hole to the inner opening edge of the shaft insertion hole by centrifugal force accompanying rotation of the differential case, and the outer peripheral surface of the pinion shaft and the inner surface of the shaft insertion hole To the sliding contact portion. Thereby, a sufficient amount of lubricating oil can be efficiently supplied to the sliding contact portion, and seizure of the sliding contact portion due to lack of lubricating oil can be prevented.

  Further, the present invention is characterized in that a concave lubricating oil reservoir portion communicating with the lubricating oil supply hole is formed on the inner surface of the through hole.

  According to this differential device, the lubricating oil adhering to the inner surface of the through hole accumulates in the lubricating oil reservoir that is formed in a concave shape with respect to the inner surface of the hole. Therefore, the accumulated lubricating oil efficiently flows into the lubricating oil supply hole due to the centrifugal force accompanying the rotation of the differential case. Thereby, a sufficient amount of lubricating oil can be efficiently supplied to the sliding contact portion.

In the present invention, the lubricating oil reservoir may be formed of an arc groove formed in an arc shape with the rotation axis as a center.
The lubricating oil reservoir may be formed of an annular recess formed in an annular shape around the pinion shaft axis.

  Further, according to the present invention, the pinion shaft is connected to the first shaft and the second shaft, which are inserted through the shaft insertion holes of the pinion gear, and fitted into the differential case, and one ends of the first shaft and the second shaft. And a cylindrical protrusion formed with a shaft connection hole for forming the lubricating oil supply hole, wherein the lubricating oil supply hole is formed by a groove formed on an inner surface of the shaft connection hole. To do.

  According to this differential device, in the divided pinion shaft, the lubricating oil supply hole can be easily formed simply by forming a groove on the inner surface of the shaft connecting hole using the shaft connecting hole.

  The present invention is characterized in that a shaft lubricating oil groove is formed in the first shaft and the second shaft so as to communicate with the shaft connecting hole.

  According to this differential device, the lubricating oil can be efficiently supplied through both the lubricating oil supply hole and the shaft lubricating oil groove.

  According to the present invention, in the pinion shaft, even when the cylindrical protrusion is formed so as to substantially close the inner opening edge of the shaft insertion hole of the pinion gear, a sufficient amount of lubricating oil is supplied to the outer periphery of the pinion shaft. It can be supplied to the sliding contact portion between the surface and the hole inner surface of the shaft insertion hole.

1 is a cross-sectional plan view of a differential device according to the present invention. It is a plane sectional view of an important section of a differential concerning a 1st embodiment of the present invention, and shows a state before jig conclusion. It is a plane sectional view of an important section of a differential concerning a 1st embodiment of the present invention, and shows a state after jig conclusion. (A), (b) is an exploded perspective view of the pinion shaft which concerns on 1st Embodiment of this invention, (b) shows the state which fractured | ruptured a part of connection member. It is II sectional drawing in FIG. 1 in 1st Embodiment. FIG. 6 is a cross-sectional view taken along line II-II in FIG. It is a disassembled perspective view of the pinion shaft which concerns on 2nd Embodiment of this invention. It is II sectional drawing in FIG. 1 in 2nd Embodiment. It is II-II sectional drawing in FIG. It is a disassembled perspective view of the pinion shaft which concerns on 3rd Embodiment of this invention. It is II sectional drawing in FIG. 1 in 3rd Embodiment. FIG. 12 is a cross-sectional view taken along the line II-II in FIG. It is II sectional drawing in FIG. 1 in 3rd Embodiment, Comprising: The example which inclined the circular arc surface of the circular arc recessed part is shown. It is drawing of 4th Embodiment, and is an external appearance perspective view at the time of forming a pinion shaft by integral molding. It is a plane sectional view of the important section of the differential concerning a 5th embodiment, and shows the state before jig fastening. FIG. 16 is a cross-sectional view taken along line I I I-I I I in FIG. 15.

“First Embodiment”
In FIG. 1, the power of a prime mover (not shown) arranged on the front side of the four-wheeled vehicle is input to a drive pinion shaft 10 via a transmission (not shown), a propulsion shaft (not shown), and a viscous joint 100. The The final reduction gear 1 includes a drive pinion gear 12 formed at the rear end of the drive pinion shaft 10, a ring gear 20 that is orthogonally engaged with the drive pinion gear 12, a differential device 2 that rotates integrally with the ring gear 20, and these devices. It is comprised from the housing etc. which accommodate. The final reduction gear 1 deflects the power input to the drive pinion shaft 10 by 90 ° and transmits it to the left and right rear wheels.

  The viscous joint 100 is a silicone oil sealed inside when there is a difference between the rotational speed of the outer plate 130 that rotates in conjunction with the front wheel and the rotational speed of the inner plate 140 that rotates in conjunction with the rear wheel. The power is transmitted between the outer plate 130 (propulsion shaft) and the inner plate 140 (drive pinion shaft 10) using the shearing force. In addition, about the specific structure of the viscous coupling 100, since it remove | deviates from the meaning of this invention, the description is abbreviate | omitted.

"Differential gear 2"
The differential device 2 is inserted through the differential case 30, two side gears 42 arranged coaxially with the rotational axis O <b> 1 of the differential case 30, two pinion gears 41 that are orthogonally engaged with the side gears 42, and the shaft insertion hole 38 of the pinion gear 41. And a pinion shaft 43 fitted to the differential case 30.

  The differential case 30 is rotatably supported by the case 50 via two tapered roller bearings 80. The case 50 is configured by combining a first case 60 and a second case 70 as will be described later.

  In FIG. 2, the differential case 30 rotates about a rotation axis O <b> 1 extending in the left-right direction, and includes a spherical shell-shaped differential case body 31, and cylindrical boss portions 32 formed at both ends of the differential case body 31, respectively. 32 and a ring-shaped flange portion 33. An opening 36 is formed at the end of the boss 32. The ring gear 20 is fastened to the flange portion 33 by bolts 34. Thereby, the ring gear 20 and the flange part 33 (difference case 30) rotate integrally. However, the ring gear 20 and the differential case 30 may be integrally cast, or the ring gear 20 and the differential case 30 may be joined by friction welding or laser welding.

  The differential case body 31 has a gear housing chamber for housing the pinion gear 41 and the side gear 42 therein. A pinion shaft 43 is attached to the differential case body 31 so as to extend in the direction of the axis O2 orthogonal to the rotation axis O1. A shaft insertion hole 38 penetrating in the direction of the axis O2 is formed in the pinion gear 41, and the pinion gear 41 is attached rotatably around a pinion shaft 43 that passes through the shaft insertion hole 38. Each side gear 42 is rotatably arranged around the rotation axis O1 on the left side or the right side of the pinion shaft 43 and meshes with the two pinion gears 41 and 41. A thrust washer 44 is interposed between the back surface (axial outer surface) of each side gear 42 and the differential case body 31.

  A drive shaft (not shown) that rotates in conjunction with the left or right rear wheel is inserted into the back surface of each side gear 42, and the side gear 42 and the drive shaft are splined together. Thereby, the side gear 42 and the drive shaft rotate integrally. The left or right drive shaft is inserted through the hollow portion of each boss portion 32. A spiral oil guide groove 35 (FIG. 1) is formed on the inner peripheral surface of each boss portion 32. The oil guide groove 35 is a groove that guides oil present outside the tapered roller bearing 80 to the center (center in the vehicle width direction) of the differential case 30.

"Pinion shaft 43"
2 and 4 to 6, the pinion shaft 43 is formed with a through-hole 24 that penetrates in the direction of the rotation axis O <b> 1, and protrudes radially outward of the pinion shaft 43 from the peripheral surface of the pinion shaft 43. A cylindrical protrusion 45 that substantially closes the inner opening edge 38 </ b> A of the insertion hole 38 is provided. The inner opening edge 38 </ b> A is formed in a tapered shape so as to increase in diameter toward the hole end of the shaft insertion hole 38. In the present embodiment, the pinion shaft 43 includes the first shaft 21 and the second shaft 22 that are fitted and fixed in the fitting holes 37 and 37 formed in the differential case 30, and the first shaft 21 and the second shaft. 22 is divided into a connecting member 23 as the cylindrical protrusion 45 in which a shaft connecting hole 26 for connecting one end of each is formed.
As will be described later, the cylindrical protrusion 45 is formed through the through hole 24 for the purpose of passing a jig 200 (FIG. 2) for suppressing the expansion of the shim 90 when the differential device 2 is assembled. It is.

  The first shaft 21 and the second shaft 22 have the same shape. The first shaft 21 is a cylindrical member, and is fixed to the differential case 30 by fitting the other end side into the insertion hole 37. On one end side of the first shaft 21, a flat portion 25 is formed along the axial center of the first shaft 21 by cutting a part of the outer peripheral surface. A pair of flat portions 25 are formed so as to face, for example, the direction of the rotation axis O1.

  The connecting member 23 is a cylindrical member, and when the connecting member 23 is incorporated into the differential case 30, its axis coincides with the rotation axis O <b> 1. In the peripheral wall of the connecting member 23, shaft connecting holes 26 and 26 for inserting respective one ends of the first shaft 21 and the second shaft 22 are formed penetrating in the radial direction of the connecting member 23. The shaft coupling holes 26 and 26 are formed at positions opposite to each other by 180 degrees across the axis (rotation axis O1) of the coupling member 23. Each shaft connecting hole 26 is formed with a flat portion 27 corresponding to the flat portion 25 of the first shaft 21 and the second shaft 22. By combining the flat portion 25 and the flat portion 27, the first shaft 21 and the second shaft 22 are not rotatable relative to the connecting member 23 around the axis O <b> 2.

  Since the connecting member 23 is disposed so as to be surrounded by the two pinion gears 41 and the two side gears 42 as can be seen from FIG. 2, the connecting member 23 has a size that does not interfere with the pinion gears 41 and the side gears 42. That is, the outer diameter dimension of the connecting member 23 is smaller than the distance dimension between the pinion gears 41, 41, and the height dimension of the connecting member 23 is smaller than the distance dimension between the side gears 42, 42. The outer diameter of the connecting member 23 is larger than the diameter of the first shaft 21 (second shaft 22). From the viewpoint of securing strength, it is desirable that the connecting member 23 has a shape as large as possible within a range that does not interfere with the pinion gear 41 and the side gear 42.

"Case 50, taper roller bearing 80, shim 90"
1 and 2, the tapered roller bearing 80 is a circle that rolls in a state sandwiched between an inner ring 81 that is externally fitted to the boss portion 32, an outer ring 82 that is internally fitted to the case 50, and the inner ring 81 and the outer ring 82. And a plurality of columnar rollers 83. The outer peripheral surface of the inner ring 81 and the inner peripheral surface of the outer ring 82 are truncated conical tapered surfaces. Further, the inner peripheral surface of the inner ring 81 is in contact with the outer peripheral surface of the boss portion 32, and the inner end surface of the inner ring 81 is in contact with the differential case body 31. The inner side means the center side in the vehicle width direction.

  As shown in FIG. 1, the case 50 has an outer fitting portion 51 that is fitted on the tapered roller bearing 80 and extends in the circumferential direction. An opening 54 is formed at the end of the outer fitting portion 51. The outer fitting portion 51 is a hole for fitting an oil seal (not shown), has a substantially L shape, and has an axial direction portion 52 extending in the axial direction (left-right direction) in the plan sectional view, and an axial direction portion 52. A radial portion 53 extending radially inward from the outer portion. The axial direction portion 52 is externally fitted to the outer ring 82. The radial direction portion 53 is disposed outside the outer ring 82 in the axial direction. A shim 90 is interposed between the radial portion 53 and the outer ring 82, and the shim 90 is sandwiched between the radial portion 53 and the outer ring 82 in the axial direction. The thickness of the shim 90 is set based on the processing accuracy of the differential case 30 and the case 50 and the size of the preload to be applied to the tapered roller bearing 80.

  The width (diameter length) of the shim 90 is set to a length in which the shim 90 projects inward from the radial portion 53 in the radial direction. That is, in FIG. 2, the inner edge portion 91 of the shim 90 faces the outside in the axial direction (left-right direction). Thus, since the inner edge 91 of the shim 90 protrudes from the radial portion 53 and faces the outside, the jig 200 and the radial portion 53 are pressed while pressing the inner edge 91 with the jig 200 described later. It is possible to combine the first case 60 and the second case 70 without causing interference. The first case 60 and the second case 70 are combined, and at the same time, the radial portion 53 sandwiches the shim 90 with the outer ring 82.

  In FIG. 1, the case 50 is divided along a plane parallel to the rotation axis O1. In this embodiment, it is divided by a dividing surface which is a vertical surface passing through the rotation axis O1, and is configured by combining a first case 60 on the front side and a second case 70 on the rear side. Accordingly, the outer fitting portion 51 is a part of the first case 60 and is a semicircular first outer fitting portion 61, and a part of the second case 70 is a semicircular second outer fitting portion 71. Will be divided. After the first case 60 and the second case 70 are combined, they are fastened and fixed to each other by bolts (not shown).

"Jig 200"
An example of the jig 200 used when assembling the differential device 2 will be described with reference to FIG. The jig 200 includes a first jig 201 and a second jig 202.

  The first jig 201 includes a columnar operation portion 210, a columnar insertion portion 220 that protrudes from one end surface of the operation portion 210 on the central axis, and passes through the opening 36 of the differential case 30. A male screw portion 230 formed at the tip, an annular shim holding portion 240 that protrudes from an outer edge portion of one end surface of the operation portion 210 and abuts against an inner edge portion 91 of one of the two shims 90A; It has.

  A hexagonal hole 211 for inserting a tool for rotating the jig 201 is formed on the other end surface of the operation unit 210. The diameter of the insertion part 220 is smaller than the diameter of the through hole 24 of the connecting member 23. The male screw portion 230 is formed so as to be positioned on the rotation axis O. The shim pressing portion 240 is a portion that presses the inner edge portion 91 of the shim 90 toward the outer ring 82 on the inner side in the axial direction. The outer diameter of the pressing portion 240 is set to be equal to or smaller than the inner diameter of the radial portion 53 of the outer fitting portion 51 so as not to interfere with the case 50. The first jig 201 described above is an integrally molded product, and the operation part 210, the insertion part 220, the male screw part 230, and the shim pressing part 240 are integrally molded.

  As for the 2nd jig | tool 202, the shim holding | suppressing part 240 contact | abuts to the inner edge part 91 of the other shim 90B. The second jig 202 has the same configuration as the first jig 201 except that a female screw part 231 is formed at the tip of the insertion part 220 instead of the male screw part 230. The female screw portion 231 is a screw hole that engages with the male screw portion 230. The second jig 202 is also an integrally molded product, and the operation part 210, the insertion part 220, the female thread part 231 and the shim pressing part 240 are integrally molded.

“Assembly method of differential device 2”
In FIG. 2, first, the differential device 2 is assembled by incorporating the pinion gear 41, the side gear 42, and the pinion shaft 43 into the differential case 30. For example, when the differential case 30 is formed integrally, the pinion gear 41 and the side gear 42 are incorporated into the differential case 30 from a window portion (not shown) formed in the differential case 30. With respect to the pinion shaft 43 that is divided, for example, only the connecting member 23 is incorporated into the differential case 30 through the window portion, and the first shaft 21 and the second shaft 22 are incorporated into the differential case 30 through the fitting holes 37. . One end of each of the first shaft 21 and the second shaft 22 is inserted into the shaft connection hole 26 of the connection member 23 and attached to the differential case 30 as an integral pinion shaft 43. The through hole 24 of the connecting member 23 is fixed in a direction along the rotation axis O1.

  If the differential case 30 has a structure that is divided along the direction of the axis O2 with the insertion hole 37 as a boundary, the differential case 30 is previously connected to the first shaft 21 and the second shaft 22 by the connecting member 23. 30 can be incorporated into the interior. In this case, the pinion shaft 43 does not necessarily have to be divided into the first shaft 21, the second shaft 22, and the connecting member 23, and may be integrally formed (see FIG. 14).

  Next, after attaching the tapered roller bearing 80 and the shim 90 to the boss portion 32 of the differential case 30, the insertion portions 220 of the first jig 201 and the second jig 202 are inserted into the opening portion 36 of the differential case 30. Each insertion part 220 also inserts the through hole 24 of the pinion shaft 43. The male screw 230 and the female screw portion 231 are screwed together by rotating the first jig 201 or the second jig 202 using a tool (not shown) inserted into the hexagonal hole 211. As shown in FIG. 3, the shim pressing portion 240 of the first jig 201 presses the inner edge portion 91 of the shim 90 </ b> A against the outer ring 82 of the tapered roller bearing 80 and the shim of the second jig 202. The pressing part 240 presses the inner edge 91 of the shim 90 </ b> B against the outer ring 82 of the tapered roller bearing 80. Thereby, the spreading of the shims 90A and 90B to the outside in the direction of the rotation axis O is suppressed.

  Next, the front half of the differential device 2 in a state where the shim 90 is pressed by the first jig 201 and the second jig 202 is attached to the first case 60 shown in FIG. That is, the tapered roller bearing 80 and the front half of the shim 90 are fitted into the semicircular arc first outer fitting portion 61 of the first case 60. At this time, since the shim 90 is pressed by the first jig 201 and the second jig 202, the rear half of the shim 90 is placed outside in the direction of the rotation axis O after being fitted into the first outer fitting portion 61. It does not spread.

Next, the second case 70 is assembled to the first case 60. That is, the taper roller bearing 80 and the rear half of the shim 90 are fitted into the semicircular arc second outer fitting portion 71 of the second case 70. At this time, since the shim 90 is pressed by the first jig 201 and the second jig 202, the second half 70 and the second case 70 do not collide with each other. The fitting portion 71 can be smoothly fitted. Since the operation part 210 of the 1st jig | tool 201 and the 2nd jig | tool 202 is settled in the opening part 54 of the external fitting part 51, the 1st jig | tool 201, the 2nd jig | tool 202, and the case 50 do not interfere. . Thereafter, the first case 60 and the second case 70 are fastened with bolts (not shown) to complete the assembly of the case 50. Thereafter, the first jig 201 and the second jig 202 are removed.
Note that the first case 60 may be combined with the second case 70 after the rear half of the differential device is first assembled into the second case 70.

  As described above, the cylindrical protrusion 45 (connection member 23) of the pinion shaft 43 is formed for the purpose of passing the jig 200 for suppressing the expansion of the shim 90 through the through hole 24. And since the through-hole 24 is formed, from the point of ensuring the strength as described above, it is desirable that the cylindrical protrusion 45 has an outer shape as large as possible within a range not interfering with the pinion gear 41 and the side gear 42. On the other hand, however, when the cylindrical protrusion 45 has a large outer shape, there is a problem that the cylindrical protrusion 45 substantially closes the inner opening edge 38A of the shaft insertion hole 38 with a slight gap.

  The differential case 30 is filled with lubricating oil, and if the pinion shaft is a straight member having no general protruding portion, the lubricating oil adhering to the surface of the pinion shaft is centrifuged as the differential case 30 rotates. The force smoothly travels along the surface of the pinion shaft and reaches the inner opening edge 38A of the shaft insertion hole 38. As a result, a sufficient amount of lubricating oil is supplied to the sliding contact portion 28 between the outer peripheral surface of the pinion shaft and the inner surface of the shaft insertion hole 38 of the pinion gear 41. However, when the cylindrical protrusion 45 substantially closes the inner opening edge 38 </ b> A of the shaft insertion hole 38, the lubricating oil is difficult to reach the inner opening edge 38 </ b> A, and the outer peripheral surface of the pinion shaft and the shaft insertion hole of the pinion gear 41. There is a possibility that a sufficient amount of lubricating oil cannot be supplied to the sliding contact portion 28 with the inner surface of the hole 38 and seizure occurs.

  4 to 6, the differential device 2 according to the present invention has a cylindrical protrusion 45, one end facing the hole inner surface 24 </ b> A of the through hole 24, and the other end being an inner opening edge of the shaft insertion hole 38. Lubricating oil supply hole 3 facing 38A is formed. The lubricating oil supply hole 3 is formed linearly along the axis O2. Further, the lubricating oil supply hole 3 of the present embodiment is constituted by a groove formed on the inner surface of the shaft coupling hole 26. Specifically, the lubricating oil supply holes 3 are formed as a pair at a substantially central position in the axial direction of the connecting member 23 (in the direction of the rotation axis O1) and at positions opposite to each other by 180 degrees across the shaft connecting hole 26. ing. The groove cross-sectional shape of the lubricating oil supply hole 3 may be a semi-circular shape or a rectangular shape. Further, the number of the lubricating oil supply holes 3 is not particularly limited.

  A shaft lubricating oil groove 4 is formed on each outer peripheral surface of the first shaft 21 and the second shaft 22 so as to communicate with the shaft connecting hole 26. In this embodiment, the shaft lubricating oil groove 4 is formed so as to overlap the lubricating oil supply hole 3. In this case, “so as to overlap” means that the lubricating oil supply hole 3 and the shaft lubricating oil groove 4 are in phase with each other around the axis O2 and have an overlap in the direction of the axis 02. Say. Thus, the lubricating oil flows through both the passages of the lubricating oil supply hole 3 and the shaft lubricating oil groove 4 to the inner opening edge 38A of the shaft insertion hole 38. The shaft lubricating oil groove 4 may be formed without overlapping the lubricating oil supply hole 3, and in this case, the shaft lubricating oil groove 4 has one end facing the hole inner surface 24A of the through hole 24 and the other end being the shaft. It is formed so as to face the inner opening edge 38 </ b> A of the insertion hole 38.

"Action"
When the differential case 30 rotates around the rotation axis O <b> 1, a part of the lubricating oil in the differential case 30 enters the through hole 24 of the connecting member 23. The lubricating oil adhering to the inner surface 24A of the through hole 24 passes through the lubricating oil supply hole 3 by the centrifugal force accompanying the rotation of the differential case 30, and also passes through the shaft lubricating oil groove 4 to the first shaft 21 and the second shaft 22. It flows to the outer peripheral surface and is supplied to the sliding contact portion 28. Accordingly, a sufficient amount of lubricating oil can be efficiently supplied to the sliding contact portion 28, and seizure of the sliding contact portion 28 due to lack of lubricating oil can be prevented.

“Second Embodiment”
The second embodiment will be described with reference to FIGS. The second embodiment and the third embodiment to be described later are forms in which a concave lubricating oil reservoir 5 communicating with the lubricating oil supply hole 3 is formed on the inner surface of the through hole 24 of the connecting member 23. The lubricating oil reservoir 5 of the second embodiment is configured by an arc groove 6 formed in an arc shape with the rotation axis O1 as the center. The arc groove 6 is formed at a substantially central position in the axial direction of the connecting member 23 (in the direction of the rotation axis O1). The cross-sectional shape of the arc groove 6 may be rectangular, semicircular, or the like.

  According to this embodiment, the lubricating oil adhering to the hole inner surface 24A of the through hole 24 is accumulated in the lubricating oil reservoir 5 (arc groove 6) formed in a concave shape with respect to the hole inner surface 24A. Therefore, the accumulated lubricating oil efficiently flows into the lubricating oil supply hole 3 due to the centrifugal force accompanying the rotation of the differential case 30, flows to the outer peripheral surfaces of the first shaft 21 and the second shaft 22, and is supplied to the sliding contact portion 28. . Accordingly, a sufficient amount of lubricating oil can be efficiently supplied to the sliding contact portion 28, and seizure of the sliding contact portion 28 due to lack of lubricating oil can be prevented.

“Third Embodiment”
A third embodiment will be described with reference to FIGS. In the third embodiment, the lubricating oil reservoir 5 is configured by an annular recess 7 formed in an annular shape around the axis O <b> 2 of the pinion shaft 43. That is, the annular recess 7 is formed in a concave shape on the inner surface 24A of the through hole 24 like a so-called counterbore hole with respect to the shaft coupling hole 26.

  According to the present embodiment, the lubricating oil attached to the hole inner surface 24A of the through hole 24 is accumulated in the lubricating oil reservoir 5 (annular recess 7) formed in a concave shape with respect to the hole inner surface 24A. Therefore, the accumulated lubricating oil efficiently flows into the lubricating oil supply hole 3 due to the centrifugal force accompanying the rotation of the differential case 30, flows to the outer peripheral surfaces of the first shaft 21 and the second shaft 22, and is supplied to the sliding contact portion 28. . Accordingly, a sufficient amount of lubricating oil can be efficiently supplied to the sliding contact portion 28, and seizure of the sliding contact portion 28 due to lack of lubricating oil can be prevented.

  The annular surface of the annular recess 7 may be formed as a surface orthogonal to the rotation axis O2, or may be formed as a surface inclined with respect to the rotation shaft 02 as shown in FIG.

“Fourth Embodiment”
When the differential case 30 has a structure divided as described above, the pinion shaft 43 is formed by integrally molding the cylindrical protrusion 45 with respect to the first shaft 21 and the second shaft 22 as shown in FIG. Can be formed. Even in such a structure, the lubricating oil supply hole 3 is formed in the cylindrical protrusion 45 so that one end faces the hole inner surface 24A of the through hole 24 and the other end faces the inner opening edge 38A of the shaft insertion hole 38. Can do.

“Fifth Embodiment”
A fifth embodiment will be described with reference to FIGS. 15 and 16. In the fifth embodiment, a female screw hole 46 is formed in the connecting member 23.

  Regarding the jig 200 used in the fifth embodiment, the first jig 201 and the second jig 202 are members having the same shape, for example, and a columnar-shaped operation unit 210 and an operation unit 210, respectively. The cylindrical insertion part 220 which protrudes from the one end surface of this to the center axis line, penetrates the opening part 36 of the differential case 30, the external thread part 230 formed in the front-end | tip of the insertion part 220, and the outer edge part of the end surface of the operation part 210 And an annular shim pressing portion 240 that abuts against the inner edge portion 91 of the shim 90.

  As described above, each insertion portion 220 of the first jig 201 and the second jig 202 is inserted into the opening 36 of the differential case 30, and the first jig 201 or the second jig is inserted using a tool (not shown) inserted into the hexagonal hole 211. By rotating the jig 202, the male screw portions 230 of the first jig 201 and the second jig 202 are screwed into the female screw holes 46 of the pinion shaft 43. By the tightening action of the screw, the shim pressing portion 240 of the first jig 201 presses the inner edge portion 91 of the shim 90A against the outer ring 82 of the tapered roller bearing 80, and the shim pressing portion 240 of the second jig 202 is shim 90B. Is pressed against the outer ring 82 of the tapered roller bearing 80. Thereby, the spreading of the shims 90A and 90B to the outside in the direction of the rotation axis O is suppressed. Thereafter, the first case 60 and the second case 70 are assembled in the same manner.

  In this way, the lubricating oil supply hole 3 is formed in the cylindrical projection 45 so that one end faces the inner surface of the female screw hole 46 and the other end faces the inner opening edge 38A of the shaft insertion hole 38 with respect to the female screw hole 46. be able to. Thereby, when the differential case 30 rotates around the rotation axis O <b> 1, a part of the lubricating oil in the differential case 30 enters the inside of the female screw hole 46 of the connecting member 23. The lubricating oil adhering to the inner surface of the female screw hole 46 flows through the lubricating oil supply hole 3 to the outer peripheral surface of the first shaft 21 and the second shaft 22 by the centrifugal force accompanying the rotation of the differential case 30 and is supplied to the sliding contact portion 28. Is done. Accordingly, a sufficient amount of lubricating oil can be efficiently supplied to the sliding contact portion 28, and seizure of the sliding contact portion 28 due to lack of lubricating oil can be prevented.

DESCRIPTION OF SYMBOLS 1 Final reduction gear 2 Differential gear 3 Lubricating oil supply hole 4 Shaft lubricating oil groove 5 Lubricating oil pool part 6 Circular groove 7 Annular recessed part 21 1st shaft 22 2nd shaft 23 Connecting member 24 Through-hole 24A Hole inner surface 26 Shaft connecting hole 28 Sliding contact portion 30 Differential case 38 Shaft insertion hole 38A Inner opening edge 41 Pinion gear 42 Side gear 43 Pinion shaft 45 Cylindrical protrusion

Claims (6)

Differential case,
A side gear disposed coaxially with the rotation shaft of the differential case;
A pinion gear orthogonally meshing with the side gear;
A pinion shaft that is inserted through the shaft insertion hole of the pinion gear and fitted into the differential case;
A differential device comprising:
The pinion shaft is formed with a through hole along the rotation axis direction, and protrudes radially outward from the peripheral surface of the pinion shaft so as to substantially close the inner opening edge of the shaft insertion hole. With
2. A differential gear according to claim 1, wherein a lubricating oil supply hole is formed in the cylindrical projection so that one end faces the inner surface of the through hole and the other end faces the inner opening edge of the shaft insertion hole.   2. The differential device according to claim 1, wherein a concave lubricating oil reservoir portion communicating with the lubricating oil supply hole is formed on an inner surface of the through hole.   The differential device according to claim 2, wherein the lubricating oil reservoir is configured by an arc groove formed in an arc shape with the rotating shaft as a center.   The differential device according to claim 2, wherein the lubricating oil reservoir is configured by an annular recess formed in an annular shape around the axis of the pinion shaft. The pinion shaft is
The first shaft and the second shaft that are respectively inserted through the shaft insertion holes of the pinion gear and are fitted into the differential case, and the shaft connection holes for connecting the respective ends of the first shaft and the second shaft are formed. A cylindrical projection, and
5. The differential device according to claim 1, wherein the lubricating oil supply hole includes a groove formed in an inner surface of the shaft coupling hole. 6.   6. The differential device according to claim 5, wherein a shaft lubricating oil groove is formed in the first shaft and the second shaft so as to communicate with the shaft connection hole.

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