JP2012241721A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential device that can suppress displacement or detachment of a seal plug.SOLUTION: The differential device includes a pair of side gears 5 and 7, and a pinion gear 9 which causes the side gears 5 and 7 to bite each other for coupling so that a differential case 3 and the side gears 5 and 7 are synchronously rotated, and allows relative rotation between the side gears 5 and 7. The pinion gear 9 is rotatably supported by a pinion shaft 49 which is supported by the differential case 3 and arranged between end parts of the side gears 5 and 7. The side gears 5 and 7 include through-holes 33 and 35 containing inner splines 37 and 39 in which a power transmission shaft is inserted in a shaft core part from an outer end for coupling. Closing plugs 45 and 47 are inserted in plug engagement parts 41 and 43 of the through-holes 33 and 35. The plugs 45 and 47 are caused to abut with or face the pinion shaft 49, for limiting movement of the plugs 45 and 47.

Description

  The present invention relates to a differential device used for an automobile or the like.

  As a conventional differential device, for example, there is one described in Patent Document 1. This differential device is a bevel gear type comprising a pinion shaft fixed to a differential case, a pinion gear rotatably supported by the pinion shaft, and a pair of side gears meshing with the pinion gear. A differential gear mechanism is provided.

  The side gear has a through hole formed in the axial center portion of the cylindrical portion, and spline teeth are formed in the through hole. A drive shaft is inserted into the spline teeth from the outer end to be fitted to the spline when assembled to the vehicle. A seal plug is attached to the inner end of the cylindrical portion by fitting, and the through hole is closed.

  This differential device is supported by a transmission case, has a completed structure in which a gap between the transmission case and the differential case is sealed, and lubricating oil is previously stored therein. The seal plug of the side gear prevents the lubricating oil previously stored in the transmission case from flowing out from the through hole of the cylindrical portion.

  When assembling to a vehicle, attach the transmission case that supports the differential unit to the vehicle body, insert the drive shaft from the outer end of the cylindrical part of the side gear, and replace the spline teeth of the drive shaft with the spline teeth of the cylindrical part. The spline is fitted to complete the assembly.

  However, when the drive shaft is inserted into the vehicle, when the spline teeth begin to engage with each other, the inside of the cylindrical portion of the side gear tends to become a sealed space between the seal plug and the drive shaft. When the shaft is forcibly inserted, the seal plug may move from the inner end of the cylindrical portion to cause an axial position shift exceeding the predetermined value or to be detached.

  Even if such a seal plug is detached, there is no means for confirmation, and an improvement has been desired.

JP 2007-146886 A

  The problem to be solved is that when the drive shaft is inserted into the side gear and connected to the side gear, the seal plug causes the axial position displacement exceeding the predetermined value or the separation due to the insertion pressure. There was a fear of doing.

  The present invention provides a case-like first rotating member that is rotatably supported and a relative rotation within the first rotating member in order to suppress axial displacement and separation of the seal plug exceeding a predetermined value. A pair of second rotating members that are freely supported and face each other in a direction along the axis of rotation, and a first rotating member that is rotatably supported by the first rotating member and meshes and couples the second rotating members. A third rotating member that rotates the second rotating members in conjunction with each other and allows relative rotation between the second rotating members, and the third rotating member is supported by the first rotating member and is configured to perform the second rotation. The second rotation member is supported by a support shaft disposed between the end portions of the member so as to freely rotate, and the second rotation member has a through hole having an engagement portion for inserting and coupling the power transmission shaft from the outer end to the shaft core portion. A plug for closing is fitted to the inner end of the through hole, The lugs abut or face the support shaft and limits the movement of the plug.

  Since the differential apparatus of the present invention has the above-described configuration, when the power transmission shaft is inserted from the outer end of the second rotating member and coupled to the engaging portion of the through hole, the inner end plug is connected to the power transmission shaft. Even if the plug is about to move, the movement is restricted by contact with the support shaft of the third rotating member, and the displacement or detachment in the axial direction exceeding the predetermined value of the plug can be suppressed. Therefore, it is possible to reliably prevent the lubricating oil from flowing out from the plug mounting portion.

It is sectional drawing of a differential apparatus. Example 1 It is an expansion perspective view of a plug. Example 1 It is sectional drawing of a differential apparatus. (Example 2)

  The purpose of suppressing the displacement or detachment of the seal plug is realized by bringing the plug into contact with or facing the support shaft of the third rotating member.

[Configuration of differential device]
1 is a cross-sectional view of a differential apparatus according to a first embodiment of the present invention.

  The differential device 1 of FIG. 1 is disposed, for example, between left and right front wheels, and is configured as a front differential device.

  The differential device 1 is rotatably supported in a transmission case on the vehicle body side.

  The differential device 1 is coupled to one end side of the left and right axle shafts, which are power transmission shafts, and the other end side of the axle shaft is coupled to the left and right front wheel sides.

  Therefore, when torque is transmitted to the differential device 1 by the driving force of the engine, torque is transmitted from the differential device 1 to the left and right front wheels via the left and right axle shafts, and driving is performed by the left and right front wheels. it can.

  The differential device 1 includes a differential case 3 as a first rotating member, side gears 5 and 7 as a pair of second rotating members, and a pinion gear 9 as a third rotating member.

  The differential case 3 includes a main body portion 11 and an end plate portion 13. The main body part 11 and the end plate part 13 have flanges 15 and 17 fastened with screws. Nuts are fastened to the flanges 15, 17 by bolts (not shown) inserted through the fastening holes 21, 23, and a ring gear (not shown) is fastened together. The differential case 3 is formed with lubricating windows 3a and 3b. Boss portions 25 and 27 are provided on the inner peripheral side of the main body portion 11 and the end plate portion 13.

  The side gears 5 and 7 are bevel gears, and cylindrical portions 29 and 31 are provided on the inner peripheral side. The cylindrical portions 29 and 31 are provided with through holes 33 and 35. The cylindrical portions 29 and 31 are for inserting and coupling the axle shaft from the outer end, and inner splines 37 and 39 are provided as engaging portions for coupling at the axial intermediate portions of the through holes 33 and 35. It has been. The inner splines 37 and 39 are formed with recesses 37a and 39a, respectively, in which the snap ring on the axle shaft side is fitted.

  On the outer end side of the cylindrical portions 29, 31, the inner diameters of the through holes 33, 35 are formed stepwise, and plug fitting portions 41, 43 are provided at the inner ends of the cylindrical portions 29, 31.

  Plug plugs 41 and 43 are fitted with plugs 45 and 47 for closing.

  FIG. 2 is an enlarged perspective view of the plug.

  As shown in FIGS. 1 and 2, the plugs 45, 47 are formed of SPCC, SPCD, SPCE, SPCF, SPCG, resin, or the like, and have outer peripheral fitting walls 45a, 47a, closing walls 45b, 47b, and convex portions 45c, 47c. The convex portions 45c and 47c protrude from the closing walls 45b and 47b, protrude inside the outer peripheral fitting walls 45a and 47a, and protrude slightly in the axial direction from the edges of the outer peripheral fitting walls 45a and 47a. The top portions 45ca and 47ca of the convex portions 45c and 47c are formed in a round shape and are positioned on the rotation axis that is the rotation center side of the side gears 5 and 7.

  The plugs 45 and 47 are fitted into the plug fitting portions 41 and 43 by press-fitting outer peripheral fitting walls 45a and 47a. A sealing rubber may be interposed between the plug fitting portions 41 and 43 and the outer peripheral fitting walls 45a and 47a.

  The pinion gear 9 is formed of a bevel gear in this embodiment, and is rotatably supported by the differential case 3 via a pinion shaft 49 that is a support shaft, and meshes and couples the side gears 5 and 7. ing. The pinion shaft 49 is held against the differential case 3 side by a spring pin and is disposed between the end portions of the side gears 5 and 7.

  The pinion gear 9 rotates the differential case 3 and the side gears 5 and 7 around the rotational axis of the differential case 3 and rotates the pinion gear 9 between the side gears 5 and 7. The relative rotation is allowed.

  The pinion shaft 49 is in contact with the top portions 45 ca and 47 ca of the plugs 45 and 47. The top portions 45ca and 47ca may be configured to face the pinion shaft 49 with a slight gap.

The differential device 1 is rotatably supported in the carrier through bearings at the boss portions 25 and 27 of the differential case 3, and the outer periphery of the cylindrical portions 29 and 31 of the side gears 5 and 7 and the carrier An oil seal is interposed between the two. The carrier contains lubricating oil and completes the lubricating structure.
[Mounting to vehicle]
The carrier is fixed to the vehicle body side, and one end sides of the left and right axle shafts are inserted into the outer ends of the cylindrical portions 29 and 31 of the side gears 5 and 7 from the left and right sides of the carrier.

  By this insertion, the spline of the axle shaft is fitted to the inner splines 37 and 39 of the side gears 5 and 7, and the snap ring pre-mounted on the axle shaft is engaged with the recesses 37a and 39a to prevent the shaft from coming off. Is done.

  When such an axle shaft is inserted, when the axle shaft spline begins to fit into the inner splines 37 and 39 of the side gears 5 and 7, the space between the axle shaft and the plugs 45 and 47 is a sealed space. When the axle shaft is forcibly inserted, the plugs 45 and 47 receive a pressing force in the axial direction through the sealed air.

  When the plugs 45 and 47 are formed in an annular shape with respect to the plug fitting portions 41 and 43 by this pressing force and try to move beyond the axial contact allowance given a predetermined value necessary for sealing, the plugs 45 and 47 Since the convex portions 45c and 47c are in contact with the pinion shaft 49, or are moved and contacted slightly, the movement in the axial direction exceeding the predetermined value is restricted.

  Therefore, even if the axle shaft is installed by forcibly pushing it against the trapped air pressure, the plugs 45 and 47 are displaced from the plug fitting portions 41 and 43 by more than a predetermined value or detached. Assembling can be performed quickly and accurately.

  When torque is transmitted from the ring gear to the differential case 3 in this assembled state, torque is transmitted to the both side gears 5 and 7 via the pinion shaft 49 and the pinion gear 9, and both side gears are transmitted. 5 and 7 rotate together with the differential case 3. As a result, torque can be transmitted to the left and right wheels via the left and right axle shafts.

  When the left and right front wheels are differentially rotated, the differential rotation of the side gears 5 and 7 is allowed by the rotation of the pinion gear 9, and the turning and the like can be performed smoothly.

  At this time, the plugs 45 and 47 are rotated together with the side gears 5 and 7 and are rotated relative to the pinion shaft 49.

The plugs 45 and 47 are in contact with the pinion shaft 49 at the tops 45 ca and 47 ca. The top portions 45ca and 47ca are formed in a round shape and are located at the rotational axis of the side gears 5 and 7. For this reason, the frictional force due to the relative rotation between the pinion shaft 49 and the top portions 45ca and 47ca is extremely small, and there is no problem of durability.
[Effect of Example]
A differential apparatus 1 according to an embodiment of the present invention includes a differential case 3 that is rotatably supported, and a pair of side gears that are relatively rotatably supported in the differential case 3 and face each other along a rotational axis. 5 and 7 are rotatably supported by the differential case 3 and meshed and coupled with the side gears 5 and 7 to rotate the differential case 3 and the side gears 5 and 7 together and between the side gears 5 and 7. And a pinion gear 9 that allows relative rotation of the pinion gear 9. The pinion gear 9 is supported by the differential case 3 and is freely rotated by a pinion shaft 49 disposed between the end portions of the side gears 5 and 7. The supported side gears 5 and 7 are provided with through holes 33 and 35 having inner splines 37 and 39 into which the power transmission shaft is inserted and coupled to the shaft core portion from the outer end, and plugs of the through holes 33 and 35 are provided. Fitting part 41 43 is fitted a plug 45, 47 for closure, the plug 45 and 47 is abutted against or opposed to the pinion shaft 49 to limit movement of the plug.

  For this reason, even if the axle shaft is forcibly pushed in against the trapped air pressure, the plugs 45 and 47 abut against the pinion shaft 49 and are fixed to the plug fitting portions 41 and 43. Assembling can be performed quickly and accurately without exceeding the value and being displaced or disengaged in the axial direction.

  The plugs 45, 47 are provided with convex portions 45 c, 47 c that contact or face the pinion shaft 49 on the rotation center side of the side gears 5, 7.

  For this reason, even if the plugs 45 and 47 rotate relative to the pinion shaft 49, wear of the plugs 45 and 47 can be suppressed and durability can be maintained.

  FIG. 3 is a cross-sectional view of the differential apparatus according to the second embodiment. The basic configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals, the corresponding components are denoted by A, and redundant description is omitted.

  As shown in FIG. 3, in the differential device 1A of the present embodiment, the shapes of the plugs 45A and 47A are changed.

  The plugs 45A and 47A include outer peripheral fitting walls 45Aa and 47Aa, closing walls 45Ab and 47Ab, and convex portions 45Ac and 47Ac. Unlike the first embodiment, the convex portions 45Ac and 47Ac are provided so as to protrude on the opposite side of the outer peripheral fitting walls 45Aa and 47Aa of the closing walls 45Ab and 47Ab.

In this embodiment, the same effects as those of the first embodiment can be obtained.
[Others]
In each embodiment, the differential device can be configured as a rear differential device, a center differential device, or the like.

1,1A differential device 3 differential case (first rotating member)
5,7 Side gear (second rotating member)
9 Pinion gear (third rotating member)
33, 35 Through hole 37, 39 Inner spline (engagement part)
45, 45, 45A, 47A Plugs 45c, 47c, 45Ac, 47Ac Convex 49 Pinion shaft (support shaft)

Claims (3)

A case-shaped first rotating member that is rotatably supported;
A pair of second rotating members which are supported in the first rotating member so as to be relatively rotatable and which face each other in a direction along the rotation axis;
The second rotating member is rotatably supported by the first rotating member, and the second rotating member is meshed and coupled to rotate the first rotating member and the second rotating member in conjunction with each other and allow relative rotation between the second rotating members. A third rotating member that
The third rotating member is supported by the first rotating member and supported by a support shaft disposed between ends of the second rotating member so as to freely rotate.
The second rotating member includes a through-hole having an engaging portion for inserting and coupling the power transmission shaft from the outer end to the shaft core portion,
A plug for closing is fitted to the inner end of the through hole,
Restricting the movement of the plug by bringing the plug into contact with or facing the support shaft;
A differential device characterized by that. The differential device according to claim 1, wherein
The plug includes a convex portion that contacts or faces the support shaft on the rotation center side of the second rotating member.
A differential device characterized by that. A differential device according to claim 1 or 2,
The first rotating member is a differential case;
The second rotating member is a pair of left and right side gears;
The third rotating member is a pinion gear;
A differential device characterized by that.