JP2017155863A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently lubricate a sliding portion between a third transmission member and a differential case while taking an advantage of a differential device, in the differential device including a first transmission member applying a first axis as a central axis, an eccentric rotary member to which a first output boss rotatable around the first axis and an eccentric shaft portion applying a second axis eccentric from the first axis as a central axis, are integrally connected, a second transmission member opposed to the first transmission member and rotatably supported by the eccentric shaft portion, the third transmission member having a second output boss rotatable around the first axis and opposed to the second transmission member, a first transmission mechanism between the first and second transmission members, and a second transmission mechanism between the second and third transmission members.SOLUTION: A spiral groove 19 capable of drawing-in a lubricant in a mission case 1, is formed on one of fitting faces of a second hub HB2 of the differential case C and a second drive shaft S2 fitted and supported to the hub, and oil passages P2i, P2m connecting a groove outlet to a thrust washer TH2, are formed between the differential case C and the third transmission member 9.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a differential device capable of distributing and transmitting a rotational force input to a differential case to first and second drive shafts via a differential mechanism in the differential case.

  As the differential device, for example, as shown in Patent Document 1, a differential mechanism is used in which a differential gear made of a bevel gear supported by a differential case is engaged with a pair of side gears sandwiched from both sides in the axial direction of the differential case. In this structure, there is a problem that the differential mechanism, and hence the differential case, increases in size in the axial direction.

  Further, for example, as in the transmission device disclosed in Patent Document 2, a first transmission member having a first axis as a central axis, a main shaft connected to the first shaft and rotatable about the first axis, and a first An eccentric rotation member integrally connected with an eccentric shaft portion having a second axis line eccentric from the axis as a central axis, and a second transmission member disposed opposite to the first transmission member and rotatably supported by the eccentric shaft portion; A third transmission member disposed opposite to the second transmission member and connected to the second shaft and capable of rotating about the first axis, and a second gear capable of transmitting torque while shifting between the first and second transmission members. There is provided a reduction gear having a structure in which a first transmission mechanism and a second transmission mechanism capable of transmitting torque while shifting between the second and third transmission members are configured to be decelerated from one of the first and second shafts to the other. Are known. And this thing of this patent document 2 is compact between the 1st, 3rd transmission member, and the 2nd transmission member in the axial direction of a case with the 1st, 2nd speed change mechanism (for example, a ball and this roll). There is an advantage that the case can be easily made flat and small in the axial direction by interlocking with a rolling ball type transmission mechanism having a pair of annular corrugated transmission grooves.

JP 2012-67889 A Japanese Patent No. 4814351

  Although the transmission device of Patent Document 1 is a differential device, it is originally difficult to flatten the differential case in the axial direction as described above.

  On the other hand, although the transmission device of Patent Document 2 has a structure that can be easily flattened in the case axial direction, a technical idea for making this structure usable as a differential device (for example, the first and second transmission mechanisms). There is no technical idea of setting each gear ratio to a specific ratio. Therefore, for example, even if a rotational force is input to the case, the rotational force cannot be distributed to the first and second shafts. Further, the transmission device of Patent Document 2 is provided with technical means for efficiently supplying lubricating oil to a narrow internal space of a flattened case, for example, a sliding portion between the third transmission member and the case. Not.

  The present invention has been made in view of such circumstances, and makes it possible to effectively utilize this as a differential device while taking advantage of the above-described advantage of the transmission device as disclosed in Patent Document 2, and further, a narrow internal space of the differential case. In particular, it is an object of the present invention to provide a differential device that can efficiently supply lubricating oil to a sliding portion between a third transmission member and a differential case.

  In order to achieve the above object, the present invention has first and second hubs arranged on the first axis on both sides and is arranged in the transmission case, and receives the rotational force and rotates around the first axis. A differential case, a first transmission member that can rotate about the first axis together with the differential case, a first output boss that can rotate about the first axis, and an eccentric shaft that has a second axis that is eccentric from the first axis as a central axis An eccentric rotating member having portions integrally connected thereto, a second transmission member disposed so as to face the first transmission member and rotatably supported by the eccentric shaft portion, and a second output rotatable around the first axis. A third transmission member having a boss and disposed opposite to the second transmission member, a first transmission mechanism capable of transmitting torque while shifting between the first and second transmission members, and the second and third A second transmission mechanism capable of transmitting torque while shifting between transmission members; A thrust washer interposed between opposing surfaces of the outer surface of the third transmission member and the inner surface of the differential case and allowing relative rotation therebetween; and the first and second speed change mechanisms include the eccentric A differential device configured to drive the third transmission member from the first transmission member with a double speed increasing ratio when the rotating member is fixed, wherein the first output boss includes: A first drive shaft that is rotatably fitted and supported on the first hub is connected to the second output boss, and a second drive shaft that is rotatably fitted and supported on the second hub is connected to the second hub. On one of the fitting surfaces of the second drive shaft and the second hub, the lubricating oil in the transmission case is applied from the outer end side of the second hub by the relative rotation of the second hub and the second drive shaft. A spiral groove that can be pulled in is provided on the inner end side, Wherein the outlet of the spiral groove oil passage for communicating the thrust washer, the first, characterized in that provided between the third transmission member and the differential case.

  The present invention also includes a differential case having first and second hubs arranged on both sides on the first axis and disposed in the transmission case and receiving a rotational force to rotate about the first axis, together with the differential case. The first transmission member that can rotate about one axis, the first output boss that can rotate about the first axis, and the eccentric shaft portion that has the second axis that is eccentric from the first axis as the central axis are integrally connected. An eccentric rotating member; a second transmission member disposed opposite to the first transmission member and rotatably supported by the eccentric shaft portion; and a second output boss rotatable about a first axis. 2. A third transmission member disposed opposite to the transmission member, a first transmission mechanism capable of transmitting torque while shifting between the first and second transmission members, and a transmission between the second and third transmission members. A second transmission mechanism capable of transmitting torque, and an outer side of the third transmission member; And a thrust washer interposed between opposing surfaces of the differential case and the inner surface of the differential case, and the first and second speed change mechanisms when the eccentric rotating member is fixed, A differential device configured to drive the third transmission member from the first transmission member with a double speed increasing ratio, wherein the first output boss is rotatably fitted to the first hub. The first drive shaft to be supported and the second output boss are coupled to the second output boss, respectively, and the second drive shaft rotatably fitted and supported to the second hub is coupled to the second output boss. A cylindrical shaft that is rotatably fitted to and supported by the second hub is integrally provided, and the second hub and the second drive shaft are provided on one of the fitting surfaces of the cylindrical shaft and the second hub. The lubricating oil in the transmission case is removed from the second hub A spiral groove that can be pulled in from the end side to the inner end side is provided, and an oil passage that communicates an outlet of the spiral groove with the thrust washer is provided between the differential case and the third transmission member. Two features.

According to the present invention, in addition to the first or second feature, the first transmission mechanism is a wave-shaped annular member that is located on a surface of the first transmission member that faces the second transmission member and that is centered on the first axis. A first transmission groove and a second transmission groove on a surface of the second transmission member facing the first transmission member and having a wave shape centered on the second axis and having a wave number different from that of the first transmission groove; And a plurality of first rolling elements that are respectively interposed at a plurality of intersecting portions of the second transmission groove and that are involved in the transmission transmission between the first and second transmission members while rolling the first and second transmission grooves. The second transmission mechanism is provided on a surface of the second transmission member facing the third transmission member and has a wave-shaped third transmission groove centered on the second axis, and the third transmission member A fourth transmission groove on the surface facing the transmission member and having a wave shape centered on the first axis and having a wave number different from that of the third transmission groove; and third and fourth transmissions And a plurality of second rolling elements that perform speed change transmission between the second and third transmission members while rolling in the third and fourth transmission grooves, the first transmission. When the wave number of the groove is Z1, the wave number of the second transmission groove is Z2, the wave number of the third transmission groove is Z3, and the wave number of the fourth transmission groove is Z4, the following equation (Z1 / Z2) × (Z3 / Z4) = 2
The third characteristic is that is established.

  According to the present invention, in addition to the second feature, an end of a connecting hole provided on the second output boss and connecting the second output boss to the second drive shaft is opposite to the second drive shaft. A fourth feature is that the portion is closed and a seal member is interposed between the cylindrical shaft and the transmission case.

  According to the first aspect of the present invention, the first transmission member that is rotatable about the first axis together with the differential case that is arranged in the transmission case and receives rotational force, and the first output boss that is rotatable about the first axis. , And an eccentric rotating member integrally connected to an eccentric shaft portion having a second axis line eccentric from the first axis as a central axis, and a first rotating member disposed so as to face the first transmission member and rotatably supported by the eccentric shaft portion. 2 transmission members, a third output member having a second output boss rotatable around the first axis and disposed opposite to the second transmission member, and torque transmission while shifting between the first and second transmission members And a second transmission mechanism capable of transmitting torque while shifting between the second and third transmission members. When the first and second transmission mechanisms fix the eccentric rotating member, the first transmission mechanism is provided. Drive 1 to 3rd transmission member with double speed ratio Because the configuration, it is possible to provide a differential device capable of easily flattened compact in the axial direction. In addition, since a thrust washer is interposed between the opposing surfaces of the third transmission member and the differential case, the axial play between the first and third transmission members can be reduced by adjusting the thickness of the thrust washer. This eliminates the good transmission function of the first and second transmission mechanisms, and also ensures smooth sliding between the opposing surfaces of the third transmission member and the differential case. Further, one of the fitting surfaces of the second drive shaft and the second hub has a spiral groove that can draw the lubricating oil in the transmission case from the outer end side to the inner end side of the second hub by the relative rotation of the second drive shaft and the second hub. Since an oil passage is provided between the differential case and the third transmission member, the lubricating oil is drawn from the transmission case side to the differential case side through the spiral groove. Lubricating oil is scattered radially between the differential case and the third transmission member by the action of centrifugal force and can be efficiently supplied to the thrust washer side. Between the thrust washer, the third transmission member and the differential case, The sliding surface can be effectively lubricated.

  In particular, according to the second feature, it is possible to achieve an effect equivalent to the above-described effect of the first feature.

  In particular, according to the third feature, the plurality of first and second rolling elements can be involved in transmission at the same time, so that the transmission torque is distributed in the circumferential direction of the transmission members on both sides of the rolling element. Thus, it is possible to provide a differential device that is lightweight and highly durable.

  According to the fourth feature, the end of the connecting hole provided on the second output boss and connecting the second output boss to the second drive shaft is closed on the side opposite to the second drive shaft, Since a sealing member is interposed between the transmission case and the second drive shaft, the lubricating oil in the transmission case and the differential case can be prevented from leaking out even when the second drive shaft is pulled out from the cylinder shaft, thus improving maintenance workability. .

1 is a longitudinal front view of a differential gear according to a first embodiment of the present invention. Exploded perspective view of the main part (differential mechanism) of the differential device 3-3 arrow sectional view of FIG. 4-4 cross-sectional view of FIG. Sectional view along arrow 5-5 in FIG. Enlarged longitudinal sectional view showing the main part (differential mechanism) of the differential device together with the flow of lubricating oil Longitudinal front view of the differential according to the second embodiment of the present invention (corresponding to FIG. 1)

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  First, a first embodiment of the present invention shown in FIGS. 1 to 6 will be described. In FIG. 1, a differential device D as a transmission device is housed in a transmission case 1 of an automobile together with a transmission.

  In the differential device D, the left and right drive axles S1, S2 (in which the rotation of the ring gear Cg that rotates in conjunction with the output side of the transmission device is arranged on the central axis of the differential device D, that is, the first axis X1, are relatively rotatable. That is, the first and second drive shafts) are distributed while allowing differential rotation between the drive axles S1 and S2. The drive axles S1, S2 and the transmission case 1 are sealed with seal members 4, 4 '.

  The bottom of the mission case 1 is configured as an oil pan (not shown) that can store a predetermined amount of lubricating oil. The stored lubricating oil in the oil pan is vigorously stirred by rotating a rotating portion in the mission case 1, for example, a differential case C described later, and scattered widely in the internal space of the case 1, and the scattered lubricating oil makes the case Each part in 1, that is, a lubricated part can be lubricated. In addition to (or instead of) the above-described lubrication structure, the lubricating oil pumped by pump means such as an oil pump may be forcibly fed to each part in the mission case 1.

  The differential device D includes a differential case C as a transmission case that is rotatably supported by the transmission case 1 around the first axis X1, and a differential mechanism 3 described later that is housed in the differential case C. The differential case C includes a ring gear Cg made of a helical gear having oblique teeth Cga provided on the outer periphery of a short cylindrical gear body, and a pair of left and right first and first pairs whose outer peripheral ends are joined to both axial ends of the ring gear Cg. Two side wall plate portions Ca and Cb are provided. At least one of the side wall plate portions Ca and Cb is provided with a drain hole (not shown) capable of appropriately discharging excess lubricating oil in the differential case C by centrifugal force or the like in the vicinity of the outer peripheral end thereof.

  The first and second side wall plate portions Ca and Cb integrally have cylindrical first and second hubs HB1 and HB2 arranged on the first axis X1 at their inner peripheral end portions, respectively. The outer peripheral portions of the hubs HB1 and HB2 are rotatably supported by the mission case 1 via bearings 2 and 2 '. The first and second drive axles S1 and S2 are fitted and supported on the inner peripheral portions of the first and second hubs HB1 and HB2 so as to be rotatable about the first axis X1, respectively. At least one of the fitting surfaces (in the illustrated example, the inner peripheral surfaces of the hubs HB1 and HB2) includes at least the hubs HB1 and HB2 and the drive axles S1 when the vehicle is moving forward (ie, when the drive axles S1 and S2 are rotating forward). The first and second spiral grooves 18 and 19 for drawing the scattered lubricating oil in the mission case 1 into the differential case C are formed along with the relative rotation with S2. The outer ends of the spiral grooves 18 and 19 are opened in the mission case 1 and the inner ends thereof are opened in the differential case C, respectively. On the outer end surfaces of the hubs HB1 and HB2, guide portions HB1a and HB2a that can efficiently guide and guide the inflow of lubricating oil from the inside of the transmission case 1 to the outer end openings (that is, the inlets) of the spiral grooves 18 and 19 protrude. Established.

  In the present embodiment, the spiral grooves 18 and 19 are exemplified as the lubricating oil supply means for supplying the lubricating oil in the mission case 1 into the differential case C. In addition to the spiral grooves 18 and 19, (Or instead), as another lubricating oil supply means, for example, an oil passage (not shown) provided with lubricating oil pumped by pump means such as an oil pump in the drive axles S1, S2 and / or the differential case C It may be supplied into the differential case C via Alternatively, as still another lubricating oil supply means, a through hole that directly communicates the inside and the outside may be formed in at least one of the side wall plates Ca and Cb of the differential case C. The spiral grooves 18 and 19 may be formed on the outer peripheral surfaces of the drive axles S1 and S2.

  Next, the structure of the differential mechanism 3 in the differential case C will be described. The differential mechanism 3 is provided integrally with the first side wall plate portion Ca and can be rotated around the first axis X1 and is spline-fitted 16 to the first drive axle S1 to be coupled to the first axis. A hollow main shaft portion 6j that integrally includes a cylindrical first spline boss SB1 (that is, a first output boss) that can rotate around X1, and a second axis X2 that is eccentric from the first axis X1 by a predetermined eccentricity e. An eccentric rotating member 6 in which an eccentric shaft portion 6e serving as a central axis is coupled and integrated, and one side portion of the eccentric rotating member 6 is disposed to face the first transmission member 5, and the eccentric shaft portion 6e is rotatable via a bearing 7 formed of a ball bearing. The annular second transmission member 8 supported by the second transmission member 8 and the other side of the second transmission member 8 are arranged opposite to each other and are spline fitted 17 to the second drive axle S2 so as to be rotatable around the first axis X1. An annular third transmission member 9 and first and second transmission members 5 A first transmission mechanism T1 which transmit the torque while shifting between 8, and a second transmission mechanism T2 which transmit the torque while shifting between the second and third transmission members 8,9.

  Thus, the second transmission member 8 is rotatably supported around the second axis X2 by the second transmission member 8 being rotatably supported on the eccentric shaft portion 6e of the eccentric rotation member 6 that rotates about the first axis X1. Can revolve around the first axis X1 relative to the main axis 6j while rotating around the second axis X2 relative to the eccentric axis 6e of the eccentric rotating member 6 around the first axis X1. .

  The second transmission member 8 has an annular first half 8a that is rotatably supported by the eccentric shaft portion 6e of the eccentric rotating member 6 via a bearing 7, and an interval between the first half 8a. An opposed annular second half 8b and a basically cylindrical connecting member 8c for integrally connecting the two halves 8a, 8b are provided. The first transmission mechanism T1 is provided between the first half 8a and the first transmission member 5, and the second transmission mechanism T2 is provided between the second half 8b and the third transmission member 9. It is done. A hollow portion SP of the second transmission member 8 is defined between the first and second half bodies 8a and 8b and the connecting member 8c.

  The connecting member 8c is provided with a plurality of first oil circulation holes 11 that communicate between the internal space IC of the differential case C and the hollow portion SP of the second transmission member 8 at equal intervals in the circumferential direction. Lubricating oil scattered in the internal space IC can be introduced into the hollow portion SP through the first oil circulation hole 11. Further, the second half body 8b is formed with a second oil circulation hole 12 that communicates the hollow portion SP with the inner peripheral side of the second transmission mechanism T2 in a circular shape with the second axis X2 as the center.

  Further, the third transmission member 9 is a cylindrical second spline boss SB2 (that is, can be rotated around the first axis X1 by being spline fitted 17 to the second drive axle S2 in the hollow portion of the third transmission member 9 (that is, the third transmission member 9). A main shaft portion 9j integrally including a second output boss) and a disc portion 9c coaxially connected to the inner end portion of the main shaft portion 9j are combined and integrated.

  Further, the first half body 8a and the second half body 8b are respectively fitted in the inner peripheral surfaces of the one end portion and the other end portion of the connecting member 8c, and the fitting portions are appropriately fixed by welding, caulking or the like. It is fixed by means.

  A first thrust washer TH1 that allows relative rotation between the inner surface of the first side wall plate portion Ca of the differential case C and the eccentric rotating member 6 is interposed between the inner surface and the first spiral. A first oil passage P1 is formed that connects the inner end opening (that is, the outlet) of the groove 18 to the inner peripheral side of the first transmission mechanism T1 through the back surface of the first thrust washer TH1. The first oil passage P1 includes an annular inner circumferential oil passage portion P1i facing the outlet of the first spiral groove 18, a plurality of concave grooves 40 provided on the inner side surface of the first side wall plate portion Ca, and a first thrust washer. An intermediate oil passage portion P1m defined between the rear face of TH1 and an annular outer peripheral oil passage portion P1o communicating directly with the inner peripheral side of the first transmission mechanism T1. Not only the inner peripheral side of the first transmission mechanism T1 but also the bearing 7 faces the outer peripheral oil passage portion P1o, and the lubricating oil flowing through the first oil passage P1 is shifted from the outer peripheral oil passage portion P1o to the first speed change. Both the mechanism T1 and the bearing 7 can be supplied.

  A second thrust washer TH2 that allows relative rotation between the inner surface of the second side wall plate portion Cb of the differential case C and the outer surface of the third transmission member 9 is interposed. At the same time, the inner end opening (that is, the outlet) of the second spiral groove 19 communicates with the internal space of the differential case C (in the illustrated example, around the outer periphery of the second transmission mechanism T2) via the back surface of the second thrust washer TH2. Two oil passages P2 are formed. The second oil passage P2 includes an annular inner peripheral oil passage portion P2i facing the outlet of the second spiral groove 19, a plurality of concave grooves 46 provided on the inner side surface of the second side wall plate portion Cb, and a second thrust washer. An intermediate oil passage portion P2m defined between the rear surface of TH2 and an outer peripheral oil passage portion P2o that directly communicates with the internal space of the differential case C. Thus, the inner peripheral oil passage portion P2i and the intermediate oil passage portion P2m of the second oil passage P2 communicate the outlet of the second spiral groove 19 as the spiral groove with the second thrust washer TH2 as the thrust washer. The oil passage of the invention is configured.

  Further, the differential mechanism 3 is opposite in phase to the eccentric shaft portion 6e of the eccentric rotating member 6 and the total center of gravity G of the second transmission member 8 across the first axis X1, and larger than the rotational radius of the total center of gravity G. And a balance weight W attached to the main shaft portion 6j of the eccentric rotating member 6. The balance weight W is composed of a disk-shaped attachment base Wm and a weight part Ww fixed to a specific region in the circumferential direction of the attachment base Wm.

  The hollow portion SP of the second transmission member 8 (connecting member 8c) is used as an accommodation space for accommodating the balance weight W. That is, the main shaft portion 6j of the eccentric rotating member 6, especially the first spline boss SB1, has an inner end portion 6ja extending to the hollow portion SP, and an extension end portion (the inner end portion 6ja) is opened. The mounting base portion Wm of the balance weight W is fitted and fixed to the end, and the opening portion on the inner end side of the hollow main shaft portion 6j (first spline boss SB1) is closed by the mounting base portion Wm. As fixing means for the mounting base Wm, conventionally known fixing means such as welding, caulking, press-fitting, and adhesion can be appropriately selected. The balance weight W (mounting base Wm) may be formed integrally with the main shaft portion 6j.

  Further, the eccentric rotating member 6 (main shaft portion 6j) has lubricating oil that has flowed into the spline fitting portion 16 between the first drive axle S1 and the main shaft portion 6j (ie, the first spline boss SB1) from the outlet of the first spiral groove 18. Is formed so as to penetrate the main shaft portion 6j in the radial direction. As shown in FIG. 3, the inner end opening of the oil hole 45 communicates directly with the spline missing tooth portion 43 on the outer periphery side of the first drive axle S1, and the lubricating oil flowing through the spline missing tooth portion 43 is efficiently obtained. The oil is supplied to the oil hole 45 and can be smoothly guided from there to the inner peripheral side of the first transmission mechanism T1.

  As shown in FIGS. 1 to 3, the first transmission member 5 has a waveform centered on the first axis X <b> 1 on the inner surface facing the one side portion (first half 8 a) of the second transmission member 8. An annular first transmission groove 21 is formed, and the first transmission groove 21 extends in the circumferential direction along a hypotrochoid curve having a virtual circle centered on the first axis X1 in the illustrated example. On the other hand, a corrugated annular second transmission groove 22 centering on the second axis X2 is formed on one side portion (first half 8a) of the second transmission member 8 facing the first transmission member 5. . In the illustrated example, the second transmission groove 22 extends in the circumferential direction along an epitrochoid curve having a virtual circle centered on the second axis X2 as a base circle, and is smaller than the wave number of the first transmission groove 21. It has a wave number and intersects the first transmission groove 21 at a plurality of locations. A plurality of first rolling balls 23 as first rolling elements are interposed at intersections (that is, overlapping portions) of the first transmission groove 21 and the second transmission groove 22, and each first rolling groove is provided. The ball 23 can roll on the inner surfaces of the first and second transmission grooves 21 and 22.

  Between the opposing surfaces of the first transmission member 5 and the second transmission member 8 (first half 8a), an annular flat first holding member H1 is interposed. The first holding member H1 can maintain the engagement state of the plurality of first rolling balls 23 with both the transmission grooves 21 and 22 at the intersections of the first and second transmission grooves 21 and 22. In addition, a plurality of circular first holding holes 31 that hold the plurality of first rolling balls 23 in a freely rotating manner while keeping their mutual spacing constant are provided at equal intervals in the circumferential direction.

  As shown in FIGS. 1, 2, and 4, a corrugated annular third transmission groove 24 centering on the second axis X <b> 2 is formed on the other side (second half 8 b) of the second transmission member 8. In the illustrated example, the third transmission groove 24 extends in the circumferential direction along a hypotrochoidal curve having a virtual circle centered on the second axis X2 as a base circle. On the other hand, on the surface of the third transmission member 9 facing the second transmission member 8, that is, on the inner side surface of the disc portion 9c, a corrugated annular fourth transmission groove 25 centering on the first axis X1 is formed. In the illustrated example, the fourth transmission groove 25 extends in the circumferential direction along an epitrochoidal curve having a virtual circle centered on the first axis X1 as a base circle, and is smaller than the wave number of the third transmission groove 24. It has a wave number and intersects with the third transmission groove 24 at a plurality of locations. A plurality of second rolling balls 26 as second rolling elements are interposed at intersections (overlapping portions) of the third transmission groove 24 and the fourth transmission groove 25, and each second rolling ball is disposed. 26 can roll on the inner surfaces of the third and fourth transmission grooves 24 and 25. In the present embodiment, the trochoidal coefficients of the first and second transmission grooves 21 and 22 and the trochoidal coefficients of the third and fourth transmission grooves 24 and 25 are set to different values.

  Between the opposing surfaces of the third transmission member 9 and the second transmission member 8 (second half 8b), an annular flat second holding member H2 is interposed. The second holding member H2 can maintain the engaged state of the plurality of second rolling balls 26 in both the transmission grooves 24 and 25 at the intersections of the third and fourth transmission grooves 24 and 25. In addition, a plurality of circular second holding holes 32 for holding the plurality of second rolling balls 26 rotatably while restricting the mutual interval between them are provided at equal intervals in the circumferential direction.

  Further, in this embodiment, a part of each of the first and second transmission grooves 21 and 22 is always open on the inner peripheral side or the outer peripheral side of the first holding member H1, and the first and second transmission grooves 21 and 22 pass through the openings IN1 and IN2. The shapes of the first holding member H1 and the first and second transmission grooves 21 and 22 are set so that the lubricating oil flow into the two transmission grooves 21 and 22 is allowed. Further, a part of each of the third and fourth transmission grooves 24, 25 is always open on the inner peripheral side or the outer peripheral side of the second holding member H2, and the third and fourth transmission grooves 24, 25 are opened through the openings IN3, IN4. The shapes of the second holding member H2 and the third and fourth transmission grooves 24 and 25 are set so that the lubricating oil flow into the 25 is allowed.

In the present embodiment described above, the wave number of the first transmission groove 21 is Z1, the wave number of the second transmission groove 22 is Z2, the wave number of the third transmission groove 24 is Z3, and the wave number of the fourth transmission groove 25 is Z4. The first to fourth transmission grooves 21, 22, 24, and 25 are formed so that the following expression is established.
(Z1 / Z2) × (Z3 / Z4) = 2
Desirably, Z1 = 8, Z2 = 6, Z3 = 6, Z4 = 4, or Z1 = 6, Z2 = 4, Z3 = 8, and Z4 = 6 as shown in the illustrated example.

  In the illustrated example, the eight-wave first transmission groove 21 and the six-wave second transmission groove 22 intersect at seven locations, and seven first rolling balls are formed at the seven intersections (overlapping portions). 23, and the 6-wave third transmission groove 24 and the 4-wave fourth transmission groove 25 intersect at five locations, and five second rolling motions at the five intersections (overlapping portions). A ball 26 is interposed.

  Thus, the first transmission groove 21, the second transmission groove 22, and the first rolling ball 23 cooperate with each other and can transmit torque while shifting between the first transmission member 5 and the second transmission member 8. The first transmission mechanism T1 is configured, and the third transmission groove 24, the fourth transmission groove 25, and the second rolling ball 26 cooperate with each other while shifting between the second transmission member 8 and the third transmission member 9. A second transmission mechanism T2 capable of transmitting torque is configured.

  Next, the operation of the first embodiment will be described.

  Now, for example, in a state where the eccentric rotary member 6 (and hence the eccentric shaft portion 6e) is fixed by fixing the right first drive axle S1, the ring gear Cg is driven by the power from the engine, and the differential case C and therefore the first When the transmission member 5 is rotated about the first axis X 1, the eight-wave first transmission groove 21 of the first transmission member 5 passes through the six-wave second transmission groove 22 of the second transmission member 8 to the first rolling ball 23. Therefore, the first transmission member 5 drives the second transmission member 8 with a speed increasing ratio of 8/6. According to the rotation of the second transmission member 8, the six-wave third transmission groove 24 of the second transmission member 8 replaces the four-wave fourth transmission groove 25 of the disk portion 9 c of the third transmission member 9. Since it is driven via the two rolling balls 26, the second transmission member 8 drives the third transmission member 9 with a speed increasing ratio of 6/4.

After all, the first transmission member 5 is
(Z1 / Z2) × (Z3 / Z4) = (8/6) × (6/4) = 2
The third transmission member 9 is driven with the speed increasing ratio.

  On the other hand, when the differential case (and hence the first transmission member 5) is rotated in the state where the third transmission member 9 is fixed by fixing the left second driving axle S2, the rotational driving force of the first transmission member 5 Due to the driving reaction force of the second transmission member 8 against the stationary third transmission member 9, the second transmission member 8 rotates while rotating about the eccentric shaft portion 6 e (second axis X 2) of the eccentric rotation member 6. Revolving around one axis line X1 drives the eccentric shaft portion 6e around the first axis line X1. As a result, the first transmission member 5 drives the eccentric rotating member 6 with a double speed increasing ratio.

  Thus, when the loads of the eccentric rotating member 6 and the third transmission member 9 are balanced with each other or change with each other, the amount of rotation and the amount of revolution of the second transmission member 8 change steplessly, and the eccentric rotation The average value of the rotational speeds of the member 6 and the third transmission member 9 is equal to the rotational speed of the first transmission member 5. Thus, the rotation of the first transmission member 5 is distributed to the eccentric rotation member 6 and the third transmission member 9, so that the rotational force transmitted from the ring gear Cg to the differential case C can be distributed to the left and right drive axles S1, S2. it can.

  At that time, Z1 = 8, Z2 = 6, Z3 = 6, Z4 = 4, or Z1 = 6, Z2 = 4, Z3 = 8, Z4 = 6 to ensure the differential function. Simplification of the eaves structure can be achieved.

  By the way, in this differential device D, the rotational torque of the first transmission member 5 is applied to the second transmission member 8 via the first transmission groove 21, the plurality of first rolling balls 23 and the second transmission groove 22, and The rotational torque of the second transmission member 8 is transmitted to the third transmission member 9 via the third transmission groove 24, the plurality of second rolling balls 26 and the fourth transmission groove 25, respectively. Torque transmission between the second transmission member 8 and the second transmission member 8 and the third transmission member 9 is performed at a plurality of locations where the first and second rolling balls 23 and 26 exist. Thus, the strength and weight of each transmission element such as the first to third transmission members 5, 8, 9 and the first and second rolling balls 23, 26 can be increased.

  In the torque transmission process of the differential device D, as described above, the stored lubricating oil at the bottom of the mission case 1 is stirred by the differential case C or the like and scattered in the mission case 1 over a wide range. As shown in FIG. 6, a part of the scattered lubricating oil is brought into the differential case C by the pulling action of the spiral grooves 18 and 19 accompanying the relative rotation between the hubs HB1 and HB2 of the differential case C and the drive axles S1 and S2. Actively supplied.

  At this time, in particular, a part of the lubricating oil that has reached the outlet of the first spiral groove 18 is the first oil passage P1 (that is, the inner oil passage portion P1i → the intermediate oil passage portion P1m → the outer periphery side) due to the centrifugal force. It flows to the bearing 7 on the inner peripheral side of the first transmission mechanism T1 and the eccentric shaft portion 6e via the oil passage portion P1o), and lubricates the first thrust washer TH1, the first transmission mechanism T1, and the bearing 7. Further, the remaining portion of the lubricating oil that has reached the outlet of the first spiral groove 18 passes through the oil hole 45 from the spline fitting portion 16 (particularly, the aforementioned spline toothless portion 43) to the outer peripheral oil passage of the first oil passage P1. Joining the portion P1o, the first transmission mechanism T1 and the bearing 7 are lubricated. In this case, in this embodiment, since the opening on the inner end side of the hollow main shaft portion 6j of the eccentric rotating member 6 is closed by the balance weight W, the passage of the lubricating oil in the main shaft portion 6j is restricted. The oil that has passed through the first transmission mechanism T1 flows into the internal space IC of the differential case C.

  On the other hand, a part of the lubricating oil that has reached the outlet of the second spiral groove 19 is subjected to the centrifugal force by the second oil passage P2 (that is, the inner oil passage portion P2i → the intermediate oil passage portion P2m → the outer oil passage). It flows into the internal space IC of the differential case C (particularly near the outer periphery of the second transmission mechanism T2) via the portion P2o), and lubricates the second thrust washer TH2 and the second transmission mechanism T2. Further, the remaining portion of the lubricating oil that has reached the outlet of the second spiral groove 19 is introduced into the inner space of the third transmission member 9 through the spline fitting portion 17, and further through the second oil circulation hole 12 to the second transmission member 8. The hollow portion SP is also introduced. The introduced lubricating oil flows radially outward by centrifugal force, flows toward the inner peripheral side of the second transmission mechanism T2 and the bearing 7 on the eccentric shaft portion 6e, and lubricates them. The oil that has passed through the second speed change mechanism T2 flows into the internal space IC of the differential case C.

  Further, since the plurality of first oil circulation holes 11 provided in the second transmission member 8 (the connecting member 8 c) are widely opened in the internal space IC of the differential case C, the internal space of the differential case C through the first oil circulation hole 11. Lubricating oil can smoothly enter and exit between the IC and the hollow portion SP of the second transmission member 8. Accordingly, part of the lubricating oil that flows into and diffuses into the internal space IC of the differential case C is also returned from the first oil circulation hole 11 to the hollow portion SP of the second transmission member 8.

  Thus, in the torque transmission process of the differential device D, the sliding portions such as the first and second transmission mechanisms T1 and T2, the bearing 7 and the thrust washers TH1 and TH2 are effectively lubricated in the differential case C. .

  In particular, according to the present embodiment, the flat first transmission member 5 that can rotate about the first axis X1 and the hollow main shaft portion 6j that can rotate about the first axis X1 (that is, the first output boss as the first output boss). An eccentric rotating member 6 integrally having an eccentric shaft portion 6e having a central axis that is a second axis X2 that is eccentric from the first axis X1 and a spline boss SB1), and an eccentric shaft portion 6e that is opposed to the first transmission member 5. And a second transmission member 8 that is rotatably supported by the second transmission member 8 and a second spline boss SB2 as a second output boss that can rotate about the first axis X1, and is flattened to be opposed to the second transmission member 8. Torque transmission while shifting between the third transmission member 9, the first transmission mechanism T1 capable of transmitting torque while shifting between the first and second transmission members 5 and 8, and the second and third transmission members 8 and 9. A second speed change mechanism T2 capable of both speed change mechanisms T1, 2 is configured to drive the first transmission member 5 to the third transmission member 9 with a double speed increasing ratio when the eccentric rotating member 6 is fixed, and thus the difference that can be easily flattened in the axial direction. A moving device D is obtained.

  In addition, in the present embodiment, since the second thrust washer TH2 as a thrust washer is interposed between the opposing surfaces of the third transmission member 9 and the differential case C (second sidewall plate portion Cb), the thrust washer TH2 By adjusting the thickness, the axial play between the first and third transmission members 5 and 9 can be easily and accurately eliminated, and a good transmission function of the first and second transmission mechanisms T1 and T2 is ensured. In addition to this, smooth sliding between the opposing surfaces of the third transmission member 9 and the differential case C can be ensured. Furthermore, the lubricating oil in the transmission case 1 can be drawn into the inner end side from the outer end side of the second hub HB2 to one of the fitting surfaces of the second drive axle S2 and the second hub HB2 by their relative rotation. The second spiral groove 19 as a spiral groove is provided, and an oil passage (that is, an inner peripheral oil passage portion P2i and an intermediate oil passage portion of the second oil passage P2) that communicates the outlet of the spiral groove 19 with the thrust washer TH2. P2m) is provided between the third transmission member 9 and the differential case C (second side wall plate portion Cb), so that the lubricating oil drawn into the differential case C side from the transmission case 1 side through the spiral groove 19 is Due to the action of centrifugal force, the oil passages P2i, P2m can be scattered radially outward and efficiently supplied to the thrust washer TH2, the thrust washer TH2, the third transmission member 9, the differential case C, Sliding surfaces between each becomes possible to effectively lubricated.

  Next, a second embodiment of the present invention will be described with reference to FIG. A first cylindrical shaft 41 rotatably fitted to and supported by the first hub HB1 of the differential case C is coaxially and integrally formed on the main shaft portion 6j (first spline boss SB1) of the eccentric rotating member 6 of the second embodiment. The second cylindrical shaft 42 is coaxially and integrally provided on the main shaft portion 9j (second spline boss SB2) of the third transmission member 9 and rotatably fitted to and supported by the second hub HB2 of the differential case C. Connected continuously.

  One of the fitting surfaces of the first hub HB1 and the first cylinder shaft 41 (the first hub HB1 in the illustrated example) has a relative rotation between the first cylinder shaft 41 and the first hub HB1 so that the inside of the transmission case 1 A first spiral groove 18 capable of drawing lubricating oil from the outer end side to the inner end side of the first hub HB1 is provided, and an outlet of the first spiral groove 18 is passed through the back surface of the first thrust washer TH1. A first oil passage P <b> 1 communicating with the inner peripheral side of the first transmission mechanism T <b> 1 is provided between the differential case C and the eccentric rotating member 6.

  One of the fitting surfaces (second hub HB2 in the illustrated example) between the second hub HB2 and the second cylinder shaft 42 is placed in the transmission case 1 by relative rotation between the second cylinder shaft 42 and the second hub HB2. Of the second hub HB2 from the outer end side to the inner end side is provided, and the outlet of the second spiral groove 19 is routed through the back surface of the second thrust washer TH2. A second oil passage P2 communicating with the internal space of the differential case C (in the illustrated example, around the outer periphery of the second speed change mechanism T2) is provided between the differential case C and the third transmission member 9. The configurations of the first and second spiral grooves 18 and 19 and the first and second oil passages P1 and P2 are the same as those in the first embodiment. If the first and second cylinder shafts 41 and 42 are sufficiently thick, the first and second spiral grooves 18 and 19 are formed on the first and second cylinder shafts 41 and 42 side. May be.

  And between the outer periphery of the outer end portions 41a and 42a extending outward from the first and second hubs HB1 and HB2 of the first and second cylindrical shafts 41 and 42, and the transmission case 1, Annular seal members 4 and 4 ′ for sealing the gap are interposed.

  Further, the inner peripheral surface of the hollow main shaft portion 9j (second spline boss SB2) of the third transmission member 9 on which the spline teeth are engraved rotates integrally with the second drive axle S2 as the second drive shaft. A blocking wall that constitutes the connecting hole of the present invention to be connected and closes the inner end side of the connecting hole (and hence the hollow portion of the main shaft portion 9j), that is, the opening opposite to the second drive axle S2. 44 is formed integrally with the main shaft portion 9j (second spline boss SB2). The blocking wall 44 may be formed separately from the main shaft portion 9j and fixed to the main shaft portion 9j by retrofitting.

  Further, the eccentric rotating member 6 of the second embodiment is not formed with a hole corresponding to the oil hole 45 of the first embodiment.

  Since the other configuration is the same as that of the first embodiment, the same reference numerals as those of the first embodiment are assigned to the respective components, and the description thereof is omitted.

  Thus, according to the second embodiment, an effect equivalent to the above-described effect of the first embodiment can be achieved.

  In addition, in the second embodiment, the opening on the inner end side of the hollow main shaft portion 6j (first spline boss SB1) of the eccentric rotating member 6 is not only closed by the balance weight W, but also the third transmission member. 9 because the opening on the inner end side of the hollow main shaft portion 9j (second spline boss SB2) 9 is closed by the closing wall 44, and the eccentric rotation member 6 does not have the oil hole 45 of the first embodiment. Even when the driving axle S1 is pulled out from the main shaft portion 6j (first cylindrical shaft 41) of the eccentric rotating member 6, the second driving axle S2 is pulled out from the main shaft portion 9j (second cylindrical shaft 42) of the third transmission member 9. Even in this case, external leakage of the lubricating oil in the transmission case 1 and the differential case C can be prevented, and the maintenance workability is improved.

  As mentioned above, although embodiment of this invention was described, this invention can perform a various design change in the range which does not deviate from the summary.

  For example, in the above-described embodiment, the differential device D is accommodated in the transmission case 1 of the automobile. However, the differential device D is not limited to the differential apparatus for automobiles, and is used for various mechanical devices. It can be implemented as a differential device.

  In the above-described embodiment, the differential device D is applied to the left / right wheel transmission system to distribute power while allowing differential rotation to the left and right drive axles S1, S2. In the present invention, the differential device may be applied to a front / rear wheel transmission system in a front / rear wheel drive vehicle to distribute power while allowing differential rotation to the front and rear drive wheels.

  Moreover, although the 2nd transmission member 8 of the said embodiment was comprised from the 1st, 2nd half bodies 8a and 8b, and the connection member 8c, the 2nd transmission member 8 is the 1st on one surface of one member. The second transmission groove 22 may be provided, and the third transmission groove 24 may be provided on the other surface.

  In the above-described embodiment, the first and second transmission mechanisms T1, T2 are both configured using a rolling ball type transmission mechanism, but are not limited to the structure of the above-described embodiment. That is, various transmission mechanisms including at least an eccentric rotating member and a second transmission member capable of rotating around the second axis and revolving around the first axis X1 in conjunction with the rotation thereof, for example, an internal planetary gear You may make it apply a mechanism, a cycloid reduction gear (speed increaser) of various structures, or a trochoid reduction gear (speed increase gear) to any one or both of a 1st or 2nd transmission mechanism.

  Moreover, in the said embodiment, although each transmission groove 21,22; 24,25 of 1st, 2nd transmission mechanism T1, T2 is made into the corrugated cyclic | annular wave groove along a trochoid curve, these transmission grooves are embodiment. For example, it may be a wave-shaped wave groove along a cycloid curve.

  Moreover, in the said embodiment, it is a ball-shaped rolling element between the 1st and 2nd transmission grooves 21 and 22 and the 3rd and 4th transmission grooves 24 and 25 of 1st, 2nd transmission mechanism T1, T2. Although the first and second rolling balls 23 and 26 are interposed, the rolling element may be a roller or a pin. In this case, the first and second transmission grooves 21 and 22, and The 3rd and 4th transmission grooves 24 and 25 are formed in the inner side surface shape where a roller-like or pin-like rolling element can roll.

  In the above-described embodiment, the eccentric rotating member 6 and the third transmission member 9 are connected to the drive axles S1 and S2 supported by the differential case C (spline fittings 16 and 17), and the drive axles S1 and S2 are interposed therebetween. In the present invention, the eccentric rotation member 6 and the third transmission member 9 may be directly supported by the differential case C.

  In the above-described embodiment, the first and second holding members H1 and H2 are configured by circular rings having inner and outer peripheral surfaces each having a perfect circle. The shape is not limited to the above-described embodiment, and may be any annular body that can hold at least a plurality of first and second rolling balls 23 and 26 at regular intervals, for example, an elliptical annular body or a waveform. A curved annular body may be used.

C... Differential case D... Differential HB1, HB2 .. First and second hubs P2i; P2m ... Inner circumferential oil passage of second oil passage constituting oil passage Part; intermediate oil passage part S1, S2,... First and second drive axles SB1, SB2 as first and second drive shafts, first and second spline bosses T1, as first and second output bosses T2, first and second transmission mechanism TH2, second thrust washer X1, X2 as thrust washer, first and second axis 1, transmission case 4 ' Seal members 5, 8, 9 .. First, second and third transmission members 6... Eccentric rotating member 6j... Main shaft portion 6e. First and second spiral grooves 21 and 22. First and second transmission grooves 23... First rolling ball 24 as a first rolling element. 25 ... third, second cylindrical shaft as a fourth transmission groove 26 ..... second rolling ball 42 ----- cylinder axis of the second rolling element

Claims (4)

The first and second hubs (HB1, HB2) arranged on the first axis (X1) are arranged in the mission case (1) on both sides and receive the rotational force around the first axis (X1). A rotating differential case (C);
A first transmission member (5) rotatable around the first axis (X1) together with the differential case (C);
The first output boss (SB1) rotatable around the first axis (X1) and the eccentric shaft portion (6e) having the second axis (X2) eccentric from the first axis (X1) as the central axis are integrally connected. An eccentric rotating member (6),
A second transmission member (8) disposed opposite to the first transmission member (5) and rotatably supported by the eccentric shaft portion (6e);
A third transmission member (9) having a second output boss (SB2) rotatable around the first axis (X1) and disposed opposite to the second transmission member (8);
A first transmission mechanism (T1) capable of transmitting torque while shifting between the first and second transmission members (5, 8);
A second transmission mechanism (T2) capable of transmitting torque while shifting between the second and third transmission members (8, 9);
A thrust washer (TH2) interposed between opposing surfaces of the outer surface of the third transmission member (9) and the inner surface of the differential case (C) and allowing relative rotation therebetween,
When the first and second speed change mechanisms (T1, T2) fix the eccentric rotation member (6), the first transmission member (5) to the third transmission member (9) are doubled. A differential configured to be driven with a ratio,
The first output boss (SB1) has a first drive shaft (S1) rotatably fitted and supported on the first hub (HB1), and the second output boss (SB2) has the first drive boss (SB2). The second drive shaft (S2) that is rotatably fitted and supported by the two hubs (HB2) is connected to each other,
On one of the fitting surfaces of the second drive shaft (S2) and the second hub (HB2), the transmission case (by the relative rotation of the second hub (HB2) and the second drive shaft (S2)). 1) A spiral groove (19) capable of drawing the lubricating oil in the second hub (HB2) from the outer end side to the inner end side is provided, and the outlet of the spiral groove (19) is connected to the thrust washer (TH2). ) Is provided between the differential case (C) and the third transmission member (9). The first and second hubs (HB1, HB2) arranged on the first axis (X1) are arranged in the mission case (1) on both sides and receive the rotational force around the first axis (X1). A rotating differential case (C);
A first transmission member (5) rotatable around the first axis (X1) together with the differential case (C);
The first output boss (SB1) rotatable around the first axis (X1) and the eccentric shaft portion (6e) having the second axis (X2) eccentric from the first axis (X1) as the central axis are integrally connected. An eccentric rotating member (6),
A second transmission member (8) disposed opposite to the first transmission member (5) and rotatably supported by the eccentric shaft portion (6e);
A third transmission member (9) having a second output boss (SB2) rotatable around the first axis (X1) and disposed opposite to the second transmission member (8);
A first transmission mechanism (T1) capable of transmitting torque while shifting between the first and second transmission members (5, 8);
A second transmission mechanism (T2) capable of transmitting torque while shifting between the second and third transmission members (8, 9);
A thrust washer (TH2) interposed between opposing surfaces of the outer surface of the third transmission member (9) and the inner surface of the differential case (C) and allowing relative rotation therebetween,
When the first and second speed change mechanisms (T1, T2) fix the eccentric rotation member (6), the first transmission member (5) to the third transmission member (9) are doubled. A differential configured to be driven with a ratio,
The first output boss (SB1) has a first drive shaft (S1) rotatably fitted and supported on the first hub (HB1), and the second output boss (SB2) has the first drive boss (SB2). The second drive shaft (S2) that is rotatably fitted and supported by the two hubs (HB2) is connected to each other,
Further, a cylindrical shaft (42) that is rotatably fitted to and supported by the second hub (HB2) is integrally connected to the second output boss (SB2).
One side of the fitting surface between the cylindrical shaft (42) and the second hub (HB2) has a relative rotation between the cylindrical shaft (42) and the second hub (HB2) so that the inside of the transmission case (1) A spiral groove (19) capable of drawing lubricating oil from the outer end side to the inner end side of the second hub (HB2) is provided, and an outlet of the spiral groove (19) is communicated with the thrust washer (TH2). An oil passage (P2i, P2m) is provided between the differential case (C) and the third transmission member (9). The first transmission mechanism (T1) is located on a surface of the first transmission member (5) facing the second transmission member (8) and has a corrugated annular first transmission groove centered on the first axis (X1). (21) and the second transmission member (8) on the surface facing the first transmission member (5) and having a corrugated annular shape centered on the second axis (X2) and having a wave number of the first transmission groove (21) Different from the second transmission groove (22) and the plurality of intersecting portions of the first and second transmission grooves (21, 22), and rolls through the first and second transmission grooves (21, 22). While having a plurality of first rolling elements (23) involved in the transmission transmission between the first and second transmission members (5, 8),
The second transmission mechanism (T2) is located on the surface of the second transmission member (8) facing the third transmission member (9) and has a wave-shaped third transmission groove centered on the second axis (X2). (24) and the third transmission member (9) on the surface facing the second transmission member (8) and having a corrugated annular shape centered on the first axis (X1) and having a wave number of the third transmission groove (25) Different from the fourth transmission groove (25) and a plurality of intersections of the third and fourth transmission grooves (24, 25), and rolls on the third and fourth transmission grooves (24, 25). A plurality of second rolling elements (26) for performing transmission transmission between the second and third transmission members (8, 9),
The wave number of the first transmission groove (21) is Z1, the wave number of the second transmission groove (22) is Z2, the wave number of the third transmission groove (24) is Z3, and the wave number of the fourth transmission groove (25) is Z4. Then, the following formula (Z1 / Z2) × (Z3 / Z4) = 2
The differential device according to claim 1, wherein:   An end of the connecting hole provided on the second output boss (SB2) for connecting the second output boss (SB2) to the second drive shaft (S2) on the side opposite to the second drive shaft (S2) 3. The differential device according to claim 2, wherein a sealing member (4 ′) is interposed between the cylindrical shaft (42) and the transmission case (1).

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