JP2017141857A - Differential gear, and sealing method in the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential gear capable of easily connecting an interval between a bottomed boss and an extension boss in a sealing state, irrespective of whether the extension boss is made of synthetic resin or metal.SOLUTION: A differential gear includes: a stepped engaging hole 38 provided in the inner periphery of one of a bottomed boss 29 and an extension boss 31; an engaging cylindrical part 37 provided on the other of the bottomed boss 29 and the extension boss 31, engaged with the stepped engaging hole 38, and abutting a tip part 37a on a bottom surface 38a of the engaging hole 38; a first accumulation part 45 defined between the bottom surface 38a of the stepped engaging hole 38 and the tip part 37a of the engaging cylindrical part 37, and having an annular shape and a closed cross section; a second accumulation part 46 defined between the bottom surface 38a of the stepped engaging hole 38 and the tip part 37a of the engaging cylindrical part 37, and having an annular shape and the inner peripheral surface opened to drive shafts 14a and 14b; and a sealant 43 filling the first and second accumulation parts 45 and 46.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a differential device including a differential case having a bearing boss that is rotatably supported by a mission case, and a differential mechanism that is accommodated in the differential case.

  Such a differential device is disclosed in Patent Document 1. In this differential device, since the bottom boss of the side gear as the output portion can be shortened by the extension boss, there is an advantage that the output member can be easily manufactured by making the output portion smaller. Moreover, the lubricating oil injected into the transmission case after the differential device is attached to the transmission case does not flow out of the transmission case and the differential case due to the oil seal or the seal portion. This means that the oil in the transmission case and differential case will still not flow out even if the drive shaft spline-fitted to the bottom boss of the output part is pulled out through the extension boss. There is an advantage that the assemblability and maintainability are improved.

Japanese Patent No. 5404727

  However, in the one described in Patent Document 1, when connecting the bottom boss of the output portion and the extension boss, a female hook-like engagement portion is provided at the outer end portion of the bottom boss of the output portion. Both bosses are connected by forming male hook-shaped engaging portions at the ends and engaging them with each other. In this connection structure, it is necessary to elastically bend the male hook-shaped engaging portion radially inward immediately before the engagement of both bosses. For this purpose, there is a restriction that the extension boss is made of synthetic resin.

  The present invention makes it possible to easily connect the bottom boss and the extension boss in a sealed state regardless of whether the extension boss is made of synthetic resin or metal while maintaining the above-mentioned advantages. An object is to provide a differential device.

  According to a first aspect of the present invention, the boss includes a differential case having a bearing boss rotatably supported by a transmission case, and a differential mechanism accommodated in the differential case, and a boss with a bottom of an output portion of the differential mechanism In addition, an extension boss inserted into the bearing boss is connected, and an oil seal is interposed between the outer end portion of the extension boss protruding from the bearing boss and the transmission case, A differential device in which a drive shaft inserted into the extension boss is fitted in a relatively non-rotatable manner, and is provided between the output portion and the extension boss, and connects both at least in the rotation direction of the output portion. A stepped fitting hole provided on one inner periphery of the bottomed boss and the extension boss, and the stepped fit provided on the other of the bottomed boss and the extension boss. A fitting cylinder portion that fits into the hole and abuts the tip portion with the bottom surface of the stepped fitting hole, and is defined between the bottom surface of the stepped fitting hole and the tip portion of the fitting cylinder portion. A first reservoir portion having an annular cross-sectional shape, a bottom surface of the stepped fitting hole, and a distal end portion of the fitting cylinder portion, the annular inner circumferential surface facing the drive shaft A differential device is provided that includes an open second reservoir and a sealing agent that fills the first and second reservoirs.

  According to the second aspect, in addition to the configuration of the first side surface, the differential device is provided on at least one of the inner peripheral surface of the stepped fitting hole and the outer peripheral surface of the fitting cylindrical portion and extends over the entire circumference. An annular groove extending is provided, and the sealing agent is introduced into the annular groove.

  According to the third aspect, in addition to the configuration of the second side surface, the extension boss has an air hole that communicates the annular groove with the outer peripheral surface of the extension boss.

  According to the fourth aspect, in addition to the configuration of any one of the first to third aspects, the differential mechanism meshes with the plurality of planetary gears housed in the differential case through the work window and the planetary gears. A side gear integrated with the bottom boss, and provided between the bearing boss and the extension boss inserted into the bearing boss from the inside of the differential case. A stopper is provided to prevent the slipping out.

  According to a fifth aspect of the present invention, there is provided a sealing method for the differential device according to the first aspect, wherein an inner corner formed by an inner peripheral surface and a bottom surface of the stepped fitting hole is provided with the first reservoir portion. Applying the sealing agent in an amount greater than or equal to the volume, pressurizing the sealing agent while fitting the fitting cylinder into the stepped fitting hole, and forming the first and second reservoirs; There is provided a sealing method comprising a step of filling the first reservoir with the sealing agent and simultaneously filling the second reservoir with the sealing agent overflowing from the first reservoir, and a step of drying the sealing agent. .

  According to the first aspect, when the bottomed boss and the extension boss are connected, the fitting tube portion provided on the other is fitted into the stepped fitting hole provided on one of the bottomed boss and the extension boss. The first boss and the second reservoir defined between the bottom surface of the fitting hole and the tip of the fitting tube portion are filled with a sealing agent, so that the space between the bottomed boss and the extended boss can be sealed. Therefore, regardless of whether the material of the extension boss is synthetic resin or metal, a special sealing member such as an O-ring is not necessary for sealing, and the bottom boss and the extension boss can be easily configured. Sealing performance can be ensured between.

  According to the second aspect, the overflowing sealing agent can escape into the annular groove. In this way, the sealing agent can be kept well.

  According to the third aspect, the sealing agent in the annular groove can touch the air introduced from the air holes. Thus, drying of the sealant is accelerated.

  According to the fourth aspect, when the planetary gear rotates in the differential case during power transmission, the side gear meshing with the planetary gear rotates. At this time, a force that pushes the extended boss outward acts on the side gear from the planetary gear. The stopper prevents the extension boss from coming out of the bearing boss of the differential case. Moreover, the fitting cylinder part provided in any one of the bottomed boss | hub and the extension boss | hub is pushed into the stepped fitting hole provided in the other, and the sealing performance of a sealing agent is maintained favorable.

  According to the fifth aspect, the amount of the sealing agent applied to the bottom surface of the stepped fitting hole or in the vicinity thereof is more than the volume of the first pool part is fitted into the stepped fitting hole of the fitting cylindrical part. By the operation, the first and second reservoirs can be filled, and the sealing work is simple. In addition, since the sealing agent overflowing from the first reservoir portion to the second reservoir portion can be visually recognized from the inside of the extension boss, it is possible to confirm whether the state of the sealing agent spread to the first and second reservoir portions is good. .

It is sectional drawing which shows roughly the whole structure of the mission unit which concerns on one Embodiment of this invention. It is sectional drawing of a differential case. It is sectional drawing which shows schematically the structure of the differential gear which concerns on other embodiment. It is sectional drawing which shows schematically the structure of the differential gear which concerns on other embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 schematically shows the overall configuration of a mission unit MU according to an embodiment of the present invention. The vehicle mission unit MU includes a differential device D and a transmission (only the output gear shown) T accommodated in the mission case 11. The differential device D according to the first embodiment includes a differential case 12. The mission case 11 incorporates a pair of bearings 13a and 13b that are arranged coaxially with the axis X and spaced apart from each other. The differential case 12 is fitted into the bearings 13a and 13b. Thus, the differential case 12 is supported by the transmission case 11 so as to be rotatable about the axis X. Drive shafts 14a and 14b are inserted into the differential case 12 coaxially with the axis X from the shaft tip. The drive shafts 14a and 14b are connected to left and right axles (not shown), respectively.

  The differential case 12 has an annular flange 15 coaxial with the axis X. A ring gear 17 that meshes with the output gear 16 of the transmission T is connected to the annular flange 15. The ring gear 17 is fixed to the annular flange 15 by fastening bolts 18.

  The differential case 12 includes a spherical shell 21, and a first bearing boss 22 a and a second bearing boss 22 b that are integrally formed with the spherical shell 21 and project on the axis X in opposite directions. The spherical shell 21 defines a spherical space 23 having a center C on the axis X. The first bearing boss 22a and the second bearing boss 22b are formed in a cylindrical shape coaxial with the axis X. The first bearing boss 22a and the second bearing boss 22b are individually fitted into the corresponding bearings 13a and 13b on the outer peripheral surface. Drive shafts 14a and 14b are inserted into the first bearing boss 22a and the second bearing boss 22b, respectively.

  The differential device D has a differential gear mechanism 24 as a differential mechanism housed in the differential case 12. The differential gear mechanism 24 includes a pinion shaft 25 that is held by the differential case 12 with an axis that passes through the center C while being orthogonal to the axis X, and a pair of planetary gears that are rotatably supported by the pinion shaft 25. And a pair of geared bosses 28 having side gears 27 meshing with the pinion gear 26. Each geared boss 28 defines an entry space 29a of the drive shafts 14a, 14b that is closed on the tip side of the drive shafts 14a, 14b, and has a bottomed boss 29 as an output connected to the drive shafts 14a, 14b. And a sleeve 31 as an extension boss that is connected to the bottom boss 29 in the axial direction of the drive shafts 14a and 14b and is formed in a cylindrical shape surrounding the drive shafts 14a and 14b.

  The side gear 27 is formed and integrated on the outer periphery of the bottomed boss 29. The side gear 27 is provided with a sliding surface 27a that is received by the partial spherical surface of the spherical shell 21 around the drive shafts 14a and 14b. The sleeve 31 is fitted into the first and second bearing bosses 22a and 22b so as to be rotatable around the axis X. Helical lubricating grooves 32 are formed on the inner peripheral surfaces of the first and second bearing bosses 22a and 22b. The drive shafts 14 a and 14 b are fitted into the corresponding sleeves 31 and are splined to the bottom boss 29 in an entry space 29 a defined by the bottom boss 29. In this way, the drive shafts 14a and 14b inserted into the sleeve 31 are fitted into the bottomed boss 29 so as not to be relatively rotatable. The outer end of the sleeve 31 protrudes from the first and second bearing bosses 22a and 22b, respectively. An oil seal 33 is interposed between the sleeve 31 and the transmission case 11 outside the differential case 12.

  The spherical shell 21 of the differential case 12 is formed with a pair of support holes 34 on a straight line passing through the center C and perpendicular to the axis X with the spherical space 23 interposed therebetween. Both ends of the pinion shaft 25 are fitted into the support holes 34. The spherical shell 21 is formed with a pin hole 35 penetrating the spherical shell 21 across the one support hole 34 in parallel with the axis X. A retaining pin 36 is press-fitted into the pin hole 35. When the retaining pin 36 penetrates the pinion shaft 25, the retaining pin 34 is prevented from being detached from the support hole 34.

  The bottomed boss 29 is provided with a fitting cylinder portion 37 that defines a passage space for the drive shafts 14a and 14b. At the inner end of the sleeve 31, a stepped fitting hole 38 that defines a space that is shaped like the fitting cylinder portion 37 is provided. The fitting cylinder portion 37 of the bottomed boss 29 is fitted into the stepped fitting hole 38.

  A connecting portion 39 is provided between the bottom boss 29 and the sleeve 31 to connect the bottom boss 29 and at least the bottom boss 29 in the rotational direction. The connecting portion 39 is provided on a first spline 39a provided at the inner end of the sleeve 31, and on a surface facing the inner end of the sleeve 31 around the fitting cylinder portion 37, and a second spline 39b engaged with the first spline 39a. Is provided. Relative rotation between the bottomed boss 29 and the sleeve 31 around the axis X is prevented according to the meshing of the first spline 39a and the second spline 39b. In addition, the connecting portion 39 may be bonded.

  During operation of the differential device D, the rotational torque of the side gear 27 is transmitted to the drive shafts 14a and 14b via the splines. At the same time, the rotation of the bottom boss 29 is transmitted to the sleeve 31 via the connecting portion 39, so that the side gear 27, the drive shafts 14a and 14b, and the sleeve 31 rotate integrally.

  Between the sleeve 31 and the first and second bearing bosses 22a and 22b, when the sleeve 31 is inserted into the first and second bearing bosses 22a and 22b from the inside of the differential case 12, the outer side of the sleeve 31 is removed. A stopper portion 41 is provided for preventing the slipping out. The stopper portion 41 is formed on the inner peripheral surface of the flange 41a provided at the inner end of the sleeve 31 and the first and second bearing bosses 22a and 22b, and has a stepped surface having an inner diameter smaller than the outer diameter of the flange 41a. 41b. When a load is applied to the sleeve 31 outward, the flange 41a is received by the stepped surface 41b, preventing the sleeve 31 from coming out outward and ensuring integral rotation with the bottom boss 29 of the sleeve 31. Is done.

  A stepped fitting hole 38 is provided on the inner periphery of the sleeve 31. On the other hand, the bottomed boss 29 is provided with a fitting cylinder portion 37 that fits into the stepped fitting hole 38. When the front end portion 37 a of the fitting tube portion 37 is brought into contact with the bottom surface 38 a of the stepped fitting hole 38, there is an annular shape between the bottom surface 38 a of the stepped fitting hole 38 and the front end portion 37 a of the fitting tube portion 37. A first reservoir 45 having a closed cross-sectional shape and a second reservoir 46 having an annular inner surface opened toward the drive shafts 14a and 14b are defined. The first reservoir portion 45 and the second reservoir portion 46 are arranged concentrically on the inner and outer periphery of the distal end portion 37 a of the fitting cylinder portion 37.

  By filling the first reservoir 45 and the second reservoir 46 with the sealing agent 43, the gap between the bottomed boss 29 and the sleeve 31 can be sealed. The sealing agent 43 is, for example, a curable resin material, and a liquid gasket is preferably used. When the liquid gasket is applied to the joint surface, it dries after a certain time and has an appropriate elasticity after drying, and thus allows slight deviation in the rotational direction and the axial direction between the bottomed boss 29 and the sleeve 31. Therefore, the sealed state between the bottomed boss 29 and the sleeve 31 can be maintained for a long time. The sealing agent 43 may be an adhesive.

  According to the configuration of the present embodiment, it does not matter whether the material of the sleeve 31 is a synthetic resin or a metal. In addition, a special sealing member such as an O-ring is not required for sealing, and not only can the number of parts be reduced, but even if there is a sealing failure in the sealing agent 43 in one reservoir, The other normal sealing agent 43 can secure the sealed state between the bottomed boss 29 and the sleeve 31 and can improve the reliability of the seal.

  Further, at least one of the inner peripheral surface of the stepped fitting hole 38 and the outer peripheral surface of the fitting cylindrical portion 37 is provided with annular grooves 42a and 42b extending over the entire circumference. In FIG. 1, an example in which annular grooves 42 a and 42 b are provided in both the stepped fitting hole 38 and the fitting cylindrical portion 37 is illustrated. The annular grooves 42a and 42b are arranged at positions facing each other. The sealing agent 43 overflowing from the first reservoir 45 is introduced into the annular grooves 42a and 42b, and functions as a sealing agent reservoir. The sealing agent 43 overflowing from the annular grooves 42 a and 42 b seals between the inner peripheral surface of the stepped fitting hole 38 and the outer peripheral surface of the fitting cylindrical portion 37.

  The sleeve 31 has an air hole 48 that communicates the annular groove 42 a with the outer peripheral surface of the sleeve 31. The air hole 48 is formed in the outer peripheral surface of the sleeve 31 and extends in the radial direction to open into the annular groove 42a, and promotes drying of the sealing agent 43 in the annular grooves 42a and 42b.

  As shown in FIG. 2, a pair of work windows 49 are provided in the spherical shell 21 of the differential case 12. The work window 49 is disposed at a position facing one diameter line orthogonal to the axis X.

  In assembling the differential device D, the sleeve 31 is first introduced into the differential case 12 from the work window 49. The sleeve 31 is inserted from the tip into the first bearing boss 22a or the second bearing boss 22b. Similarly, the other sleeve 31 is inserted into the remaining first or second bearing bosses 22a and 22b. Subsequently, the bottomed boss 29 having the side gear 27 is introduced from the work window 49. The bottomed bosses 29 are fitted into the corresponding sleeves 31 in order. The fitting cylinder portion 37 of the bottomed boss 29 is inserted into the stepped fitting hole 38 of the sleeve 31. At this time, the first spline 39a and the second spline 39b mesh with each other, and integral rotation of the sleeve 31 and the bottomed boss 29 is ensured. Subsequently, the pinion gear 26 is introduced from the work window 49. The pinion gear 26 is meshed with the side gear 27. Thereafter, the pinion shaft 25 is inserted into the support hole 34 of the differential case 12. The retaining pin 36 is press-fitted. According to the configuration of this embodiment, the boss 29 with the bottom of the side gear can be shortened by the sleeve 31. Therefore, even if the differential case 12 is a compact integrated type, the inside of the differential case 12 is narrow from the work window 49 of the differential case 12. It is possible to incorporate side gears etc.

  Prior to the fitting of the bottomed boss 29, the sealing agent 43 in an amount equal to or larger than the volume of the first reservoir 45 is applied to the annular inner corner between the inner peripheral surface of the stepped fitting hole 38 and the bottom surface 38a over the entire circumference. Apply and store. The sealing agent 43 may be applied before the sleeve 31 is introduced into the differential case 12. The sealing agent 43 is pressurized while fitting the fitting cylindrical portion 37 of the bottomed boss 29 into the stepped fitting hole 38 to form the first and second reservoir portions 45 and 46, and the first reservoir. The portion 45 is filled with the sealing agent 43, and at the same time, the second reservoir 46 is filled with the sealing agent 43 overflowing from the first reservoir 45. Further, the sealing agent 43 flows into the annular grooves 42a and 42b through the gap between the inner peripheral surface of the stepped fitting hole 38 and the outer peripheral surface of the bottomed boss 29, and fills the annular grooves 42a and 42b. Thus, the sealing agent 43 is filled and then dried.

  According to the present embodiment, the sealing agent 43 applied to the bottom surface 38 a of the stepped fitting hole 38 and / or the vicinity thereof in an amount equal to or larger than the volume of the first reservoir 45 is stepped on the fitting cylindrical portion 37. By the fitting operation to the fitting hole 38, the first and second reservoirs 45 and 46 can be filled, and the sealing work is simple. In addition, since the sealing agent 43 overflowing from the first reservoir 45 to the second reservoir 46 can be visually recognized from the inside of the sleeve 31, the quality of the state of the sealing agent 43 reaching the second reservoir 46 can be confirmed. Can do.

  In addition, when the bottom boss 29 is assembled, the sealing agent 43 before drying easily flows, so that the resistance during assembly is small, and the cycle time can be reduced.

  Furthermore, since the sealing agent 43 overflowing from the first reservoir 45 can escape to the annular groove 42, the sealing agent 43 can be held well.

  The assembled differential device D is assembled in the mission case 11. An oil seal 33 is interposed between the outer end of the sleeve 31 and the transmission case 11. Thereafter, lubricating oil is injected into the mission case 11. A part of the lubricating oil flows into the differential case 12 through the work window 49 and is used for lubricating each part of the differential gear mechanism 24.

  The lubricating oil injected into the mission case 11 does not flow out of the mission case 11 and the differential case 12 due to the seal portion of the oil seal 33 and the sealing agent 43. This means that the oil in the transmission case 11 and the differential case 12 still does not flow out even when the drive shafts 14a and 14b that are spline-fitted to the bottom boss 29 of the side gear through the sleeve 31 are pulled out. Assembling and maintenance properties can be improved while achieving compactness.

  In the differential device D, a seal between the bottomed boss 29 and the sleeve 31 as an output portion can be achieved without using a special seal member such as an O-ring, and the number of parts can be reduced. When assembling, the fitting cylinder portion 37 of the bottomed boss 29 may enter the stepped fitting hole 38 of the sleeve 31 as it is, and the bottomed boss 29 and the sleeve 31 are connected without deformation of the bottomed boss 29. Is achieved. Therefore, regardless of whether the material of the sleeve 31 is a synthetic resin or a metal, a sealing property can be ensured between the bottomed boss 29 and the sleeve 31. The bottomed boss 29 may be closed by a bottom plate continuous from a cylindrical body based on integral molding as in the present embodiment, or may be one in which one end of the boss is closed by a separate closure cap. There may be.

  When the pinion gear 26 rotates in the differential case 12 during power transmission, the side gear 27 that meshes with the pinion gear 26 rotates. At this time, a force for pushing the sleeve 31 outward acts on the side gear 27 from the pinion gear 26. The stopper portion 41 prevents the sleeve 31 from coming out of the bearing bosses 22 a and 22 b of the differential case 12. The bottomed boss 29 is pushed into the stepped fitting hole 38 of the sleeve 31, and the sealing performance of the sealing agent 43 is maintained well.

  FIG. 3 schematically shows the overall configuration of the differential device D2 according to the second embodiment. The differential device D2 uses a pair of rolling ball type speed change mechanisms, and includes a first half having a first bearing boss 22a and a second half having a second bearing boss 22b. A differential case 52 formed by being coupled to each other is provided. The first and second bearing bosses 22a and 22b are configured in the same manner as described above. The ring gear 17 is fixed to the differential case 52.

  The differential device D2 includes a differential mechanism 53 housed in the differential case 52. The differential mechanism 53 is formed integrally with the differential case 52, and includes a first transmission member 54 having the first axis X1 as a central axis, a main shaft portion 55j that rotates about the first axis X1, and the first axis X1. An eccentric rotating member 55 that integrally connects the eccentric shaft portions 55e positioned on the eccentric second axis X2 and a second transmission that is disposed adjacent to the first transmission member 54 and is rotatably supported by the eccentric shaft portion 55e. The first transmission member 56, a third transmission member 57 that is disposed adjacent to the second transmission member 56 and rotates about the first axis X1, and a first gear member that can transmit torque while shifting between the first and second transmission members 54, 56. A first transmission mechanism T1 and a second transmission mechanism T2 capable of transmitting torque while shifting between the second and third transmission members 56 and 57; The first transmission member 54 and the third transmission member 57 define an entry space 29a of the drive shafts 14a and 14b that is closed at the distal end sides of the drive shafts 14a and 14b, and serve as output units connected to the drive shafts 14a and 14b. And a sleeve 31 as an extension boss that is connected to the bottom boss 29 in the axial direction of the drive shafts 14a and 14b and is formed in a cylindrical shape surrounding the drive shafts 14a and 14b. The bottomed boss 29 and the sleeve 31 may be configured in the same manner as described above.

  The first speed change mechanism T1 is formed on the first transmission member 54 while facing the second transmission member 56, and is continuous with the first axis X1 as a center (in the embodiment, a trochoidal shape or a cycloid shape, the same applies hereinafter). The first transmission groove 58 is formed on the second transmission member 56 so as to face the first transmission member 54, and a wave ring is drawn around the second axis X2, which is different from the wave number of the first transmission groove 58. The first and second transmission grooves 59 and 59 are interposed between a plurality of overlapping portions of the second transmission groove 59 having the wave number and the first and second transmission grooves 58 and 59. 2 and a plurality of first rolling elements 61 that perform transmission transmission between the transmission members 54 and 56. The 1st rolling element 61 is comprised by the spherical body of a metal body, for example.

  The second transmission mechanism T2 is formed in the second transmission member 56 while facing the third transmission member 57, and includes a third transmission groove 62 that draws a continuous wave ring around the second axis X2, and the second transmission member. A fourth transmission groove 63 having a wave number different from the wave number of the third transmission groove 62, which is formed in the third transmission member 57 while being faced to 56, draws a continuous wave ring around the first axis X 1, and The third and fourth transmission grooves 62 and 63 are interposed in a plurality of overlapping portions, and shift transmission between the second and third transmission members 56 and 57 is performed while rolling the third and fourth transmission grooves 62 and 63. A plurality of second rolling elements 64 are included. The 2nd rolling element 64 is comprised by the spherical body of a metal body, for example.

  A synchronous rotation mechanism I is connected to the second transmission member 56. The synchronous rotation mechanism I synchronously rotates the eccentric rotation member 55 and the balance weight W while holding the balance weight W at a position opposite to the eccentric shaft portion 55e with respect to the first axis X1. When the wave number of the first transmission groove 58 is Z1, the wave number of the second transmission groove 59 is Z2, the wave number of the third transmission groove 62 is Z3, and the wave number of the fourth transmission groove 63 is Z4, (Z1 / Z2) Each wave number is set so that x (Z3 / Z4) = 2 holds.

  The rotational force input from the in-vehicle engine to the differential case 52 via the transmission T is transmitted to the eccentric rotation member 55 and the third transmission member 57 via the first and second transmission mechanisms T1 and T2, thereby causing the eccentricity to occur. The rotating member 55 and the third transmission member 57 can be rotationally driven while allowing mutual differential rotation. Since the second embodiment is otherwise the same as the first embodiment, portions corresponding to those of the first embodiment are denoted by the same reference numerals, and redundant description is omitted. In the second embodiment, the same operational effects as those of the first embodiment can be basically achieved.

  FIG. 4 schematically shows the overall configuration of the differential device D3 according to the third embodiment. The differential device D3 is different from that of the first embodiment in that the stepped fitting hole 38 is provided in the bottom boss 29, the fitting cylindrical portion 37 is provided in the sleeve 31, and the annular groove 42 is not provided. Different from the differential device D.

  Also in the differential device D3 of the third embodiment, the first and second reservoir portions 45 and 46 are defined on the bottom surface 38a of the stepped fitting hole 38 and the tip portion 37a of the fitting cylinder portion 37, and these are defined. The sealing agent 43 that fills the first and second reservoir portions 45 and 46 can ensure sealing performance with a simple configuration.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, in the said embodiment, it can replace with the bolt fastening of the ring gear 17 and the flange 15, and can also employ | adopt the coupling | bonding by welding. Further, the inner peripheral surface of the differential case 12 may be a square surface or a cylindrical surface instead of a spherical surface. The two sleeves 31 may have different lengths. Further, the present invention may be applied to only one of the pair of bearing bosses. If the stopper portion 41 is not provided, the bottom boss 29 is assembled into the differential cases 12 and 52, and then the sleeve 31 is passed from the outside of the differential cases 12 and 52 to the first bearing boss 22a or the second bearing boss 22b. The bottom boss 29 may be connected.

  DESCRIPTION OF SYMBOLS 11 ... Mission case, 12 ... Differential case, 14a ... Drive shaft, 14b ... Drive shaft, 22a ... First bearing boss, 22b ... Second bearing boss, 24 ... Differential mechanism (differential gear mechanism), 26 ... Planetary gear ( Pinion gear), 27 ... side gear, 29 ... bottom boss as output part, 31 ... extension boss (sleeve), 33 ... oil seal, 37 ... fitting cylinder part, 38 ... stepped fitting hole, 39 ... connecting part, DESCRIPTION OF SYMBOLS 41 ... Stopper part, 42a ... Annular groove, 42b ... Annular groove, 43 ... Sealing agent, 48 ... Air hole, 49 ... Working window, 52 ... Differential case, 53 ... Differential mechanism, D ... Differential device.

Claims (5)

A differential case having a bearing boss rotatably supported by the transmission case;
A differential mechanism housed in the differential case,
An extension boss fitted to the bearing boss is connected to the bottom boss of the output portion of the differential mechanism, and an oil seal is provided between the outer end portion of the extension boss protruding from the bearing boss and the transmission case. Is installed, and the bottom boss is a differential device in which a drive shaft that is inserted into the extension boss is fitted in a relatively non-rotatable manner,
A connecting portion that is provided between the output portion and the extension boss, and connects both of them in the rotational direction of the output portion;
A stepped fitting hole provided on one inner circumference of the bottomed boss and the extended boss;
A fitting tube portion that is provided on the other of the bottom boss and the extension boss and is fitted into the stepped fitting hole, and a tip portion is brought into contact with the bottom surface of the stepped fitting hole,
A first reservoir portion defined between a bottom surface of the stepped fitting hole and a front end portion of the fitting cylinder portion, and having a circular cross-sectional shape closed;
A second reservoir portion defined between a bottom surface of the stepped fitting hole and a tip portion of the fitting cylinder portion, and having an annular shape and having an inner peripheral surface opened toward the drive shaft;
And a sealing agent that fills the first and second reservoirs. The differential device according to claim 1, further comprising an annular groove that is provided on at least one of an inner peripheral surface of the stepped fitting hole and an outer peripheral surface of the fitting cylindrical portion and extends over the entire circumference.
The differential device according to claim 1, wherein the sealing agent is introduced into the annular groove.   The differential device according to claim 2, wherein the extension boss has an air hole communicating the annular groove with an outer peripheral surface of the extension boss. 4. The differential device according to claim 1, wherein the differential mechanism includes a plurality of planetary gears housed in a differential case through the work window and the bottom boss engaged with the planetary gears. 5. Including a side gear integrated with
A stopper portion is provided between the bearing boss and the extension boss inserted into the bearing boss from the inside of the differential case, and prevents the extension boss from slipping outward. Differential device. A sealing method for a differential device according to claim 1,
Applying a sealing agent in an amount equal to or larger than the volume of the first reservoir to the inner corner formed by the inner peripheral surface and the bottom surface of the stepped fitting hole;
While pressurizing the sealing agent while fitting the fitting tube portion into the stepped fitting hole to form the first and second reservoirs, the first reservoir is filled with the sealing agent, Simultaneously filling the second reservoir with the sealing agent overflowing from the first reservoir,
And a step of drying the sealing agent.

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