JP2017110730A - Differential gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable both transmission mechanisms to be individually machined for a second transmission member, to improve productivity and small-sized device to be attained for a transmission case comprising: a first transmission member having a first axis line as a central axis line; an eccentric rotation member having a main shaft part rotatable around a first axis line and an eccentric shaft part having a second axis line as a central axis line connected to each other; a second transmission member oppositely arranged against the first transmission member and rotatably supported at the eccentric shaft part; a third transmission member oppositely arranged against the second transmission member and rotatable around the first axis line; 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 second transmission member 8 comprises a first half-body 8a supported at an eccentric shaft part 6e, a second half body 8b oppositely faced against the first half body 8a while holding a space SP therein and a connecting member 8c between both half bodies 8a, 8b, a first transmission mechanism T1 is arranged between the first half-body 8a and the first transmission member 5 and a second transmission mechanism T2 is arranged between the second half body 8b and the third transmission member 9, and a first spline boss SB1 is arranged to cause an inner end part 6ja to expand into the space SP.SELECTED DRAWING: Figure 1

Description

  The present invention includes a first transmission member that is supported by a differential device, particularly a differential case so as to rotate with the differential case, and that can rotate about a first axis, a main shaft that can rotate about the first axis, and a first axis. An eccentric rotating member in which an eccentric shaft portion having the eccentric second axis as a central axis is integrally connected; a second transmission member that is disposed to face the first transmission member and is rotatably supported by the eccentric shaft portion; A third transmission member disposed opposite to the second transmission member and supported by the differential case and capable of rotating about the first axis, and a first transmission mechanism capable of transmitting torque 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.

  In the above-described differential device, the first and second speed change mechanisms are configured to drive the third transmission member from the first transmission member with a double speed increase ratio when the eccentric rotation member is fixed, for example. The rotational force of the differential case (first transmission member) can be distributed while allowing differential rotation to the first and second drive shafts connected to the eccentric rotation member and the third transmission member, respectively. In such a differential device, the first drive shaft is connected to the first spline boss integrated with the main shaft portion of the eccentric rotating member, and the second drive shaft is connected to the second spline boss integrated with the third transmission member. Applicants have already filed applications for connecting the eccentric rotating member and the third transmission member to the first and second drive shafts in a spline-fitted manner (see Patent Document 1 below).

PCT / JP2015 / 066461

  In the differential device of Patent Document 1, since the second transmission member is formed as a single piece, the first and second transmission mechanisms are provided on one side and the other side of the second transmission member of the single piece. However, it was not advantageous from the viewpoint of productivity.

  Further, when it is attempted to sufficiently secure the fitting depth of the first and second spline bosses with the first and second drive shafts, both spline bosses are elongated in the axial direction outside the second transmission member. This is necessary and is not advantageous from the viewpoint of reducing the size of the apparatus in the axial direction.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a differential device that can solve the above problems all at once.

  In order to achieve the above object, the present invention provides a first transmission member that is supported by the case so as to rotate with the differential case and is rotatable about the first axis, a main shaft portion that is rotatable about the first axis, An eccentric rotating member integrally connected with an eccentric shaft portion having a second axis that is eccentric from one axis as a central axis, and a first member that is opposed to the first transmission member and is rotatably supported by the eccentric shaft portion. 2 transmission members, a third transmission member disposed opposite to the second transmission member, supported by the differential case and rotatable about the first axis, and torque while shifting between the first and second transmission members A first transmission mechanism capable of transmitting and a second transmission mechanism capable of transmitting torque while shifting between the second and third transmission members; and a first drive shaft is spline-fitted to the main shaft portion. 1 spline boss The transmission member includes differential gears each including a second spline boss for spline-fitting a second drive shaft, wherein the second transmission member is rotatably supported by the eccentric shaft portion and A first half facing the transmission member; a second half facing the first half with a space; and a connecting member for integrally connecting the first and second halves. The first transmission mechanism is provided between the first half and the first transmission member, and the second transmission mechanism is provided between the second half and the third transmission member. The first feature of the first spline boss is that the inner end of the first spline boss is disposed so as to project into the space between the first and second halves.

  Further, according to the present invention, in addition to the first feature, the space has a center of gravity opposite to the total center of gravity of the eccentric shaft portion and the second transmission member and is coupled to the first spline boss. The second feature is that the balance weight is arranged.

  According to the first feature of the present invention, the second transmission member is rotatably supported by the eccentric shaft portion of the eccentric rotation member and faces the first transmission member. A second half that faces the space and a connecting member that integrally connects the first and second halves are provided, and the first half is between the first half and the first transmission member. Since the speed change mechanism and the second speed change mechanism are respectively provided between the second half and the third transmission member, the first and second speed change mechanisms are processed on one side and the other side of the second transmission member. , It is possible to perform individual processing on the first and second halves, which can contribute to productivity improvement. In addition, the first spline boss is disposed so that the inner end portion of the first spline boss projects into the space between the first and second halves (that is, the hollow portion of the second transmission member). Even if the first transmission spline boss does not extend long in the axial direction outside the second transmission member, the first spline boss can be sufficiently fitted with the first drive shaft, and the differential device can be reduced in the axial direction. Is advantageous.

  In particular, according to the second feature, a balance weight connected to the first spline boss having a center of gravity opposite to the total center of gravity of the eccentric shaft portion and the second transmission member is disposed in the space. Therefore, it is possible to effectively suppress the occurrence of vibration due to the eccentric rotation of the eccentric shaft portion and the second transmission member. In addition, as described above, the space between the two halves used for the inward extension of the first spline boss can be used as the installation space for the balance weight, so that the size of the differential device increases due to the installation of the balance weight. It can be avoided.

1 is a longitudinal front view of a differential device as a transmission device according to an 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.

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

  First, an embodiment of the present invention shown in FIGS. 1 to 5 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 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.

  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.

  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 main shaft portion 6j including a cylindrical first spline boss SB1 rotatable around X1 and an eccentric shaft portion 6e having a second axis line X2 eccentric from the first axis line X1 by a predetermined amount of eccentricity e as a central axis line are integrally coupled. The eccentric eccentric member 6 and the annular second transmission member, one side of which is opposed to the first transmission member 5 and rotatably supported by the eccentric shaft portion 6e via a bearing 7 made of a ball bearing. 8, an annular third transmission member 9 that is disposed opposite to the other side of the second transmission member 8 and is spline-fitted 17 to the second drive axle S2 and rotatable about the first axis X1, Torque can be transmitted while shifting between the first and second transmission members 5 and 8 It comprises a first transmission mechanism T1, and a second transmission mechanism that transmit the torque T2 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.

  The third transmission member 9 includes a main shaft portion 9j including a cylindrical second spline boss SB2 that is spline fitted 17 to the second drive axle S2 and is rotatable about the first axis X1, and the main shaft portion 9j. A disk portion 9c provided coaxially with the inner end portion is coupled and integrated.

  In addition, annular step portions 8c1 and 8c2 for fitting the first half body 8a and the second half body 8b respectively into the spigot are formed on the inner peripheral surfaces of the one end and the other end of the connecting member 8c. The fitting portion is fixed by appropriate fixing means such as welding or caulking.

  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 opposed surface of the eccentric rotating member 6 is interposed. Further, a second thrust washer TH2 that allows relative rotation between the inner side surface of the second side wall plate portion Cb of the differential case C and the third transmission member 9 is interposed.

  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. This balance weight W is comprised from the cyclic | annular attachment base Wm and the weight part Ww fixedly provided in the circumferential direction specific area | region 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 outer periphery of the extending end portion (the inner end portion 6ja). A balance weight W is attached to the. The mounting base portion Wm is fitted to the outer periphery of the inner end portion 6ja of the main shaft portion 6j (first spline boss SB1). Between the fitting surfaces, axial sliding therebetween is allowed but relative to each other. A flat engagement surface 14 for preventing rotation that restricts rotation is provided. For fixing the balance weight W to the main shaft portion 6j, a retaining ring 10 such as a circlip as a retaining member for preventing the attachment base portion Wm from being detached from the main shaft portion 6j is detachably attached to the inner end portion 6ja. Is done. For the mounting, a locking groove in which the retaining ring 10 can be resiliently locked is formed in the outer periphery of the inner end 6ja.

  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.

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 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 above-described torque transmission process of the differential device D, 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. A part of the scattered lubricating oil is actively supplied 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. From there, it is further introduced into the internal space of the differential mechanism 3, that is, the hollow portion SP of the second transmission member 8 through the spline fitting portions 16, 17. The introduced lubricating oil flows radially outward by centrifugal force in the hollow portion SP and 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. To do.

  In particular, according to the present embodiment, the second transmission member 8 is divided into the connecting member 8c and the first and second halves 8a and 8b sandwiching the connecting member 8c. The processing of the two speed change mechanisms T1 and T2 can be performed individually for each of the half bodies 8a and 8b, so that the processing is easy and the productivity is improved. Further, the first spline boss SB1 for spline fitting 16 the first drive axle S1 of the main shaft portion 6j of the eccentric rotating member 6 has an inner end portion 6ja of the hollow portion SP of the second transmission member 8 (that is, the first and second transmission members 8). Since the first spline boss SB1 does not extend long in the axial direction outside the second transmission member 8, the main shaft portion is disposed so as to project over the internal space sandwiched between the second half bodies 8a and 8b. It is possible to sufficiently secure the fitting depth with the first driving axle S1 of 6j, which is advantageous in reducing the size of the differential device D in the axial direction.

  In addition, a balance weight W having a center of gravity opposite to the total center of gravity G of the eccentric shaft portion 6e and the second transmission member 8 and connected to the first spline boss SB1 is disposed in the hollow portion SP. Therefore, it is possible to effectively suppress the occurrence of vibration due to the eccentric rotation of the eccentric shaft portion 6e and the second transmission member 8. Moreover, as described above, the space between the halves 8a and 8b used for the inward projection of the main shaft portion 6j (first spline boss SB1), that is, the hollow portion SP can be used as the installation space for the balance weight W. It is possible to avoid an increase in the size of the differential device D due to the installation of the balance weight W.

  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, but the differential device D is not limited to the differential apparatus for automobiles, 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.

  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 speed change 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 in conjunction with the rotation thereof, such as an inscribed planetary gear mechanism Alternatively, a cycloid speed reducer (speed increaser) or a trochoid speed reducer (speed increaser) having various structures may be applied to one or both of the first and second transmission mechanisms T1 and T2.

  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.

  In the above-described embodiment, the first and second ball-shaped first and second transmission grooves 21 and 22 and the third and fourth transmission grooves 24 and 25 of the first and second transmission mechanisms T1 and T2 are provided. Although two rolling elements 23 and 26 are interposed, the rolling elements may be in the form of a roller or a pin. In this case, the first and second transmission grooves 21 and 22, and the third and fourth The transmission grooves 24 and 25 are formed in an inner surface shape so that a roller-like or pin-like rolling element can roll.

  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.

  Further, when the first and second rolling balls 23 and 26 can smoothly roll without the first and second holding members H1 and H2, the first and second holding members H1 and H2 are omitted. May be.

C .... Differential case as transmission case D ... Differential device G as transmission device ... Total center of gravity SB1, SB2 ... First and second spline boss SP ... ... Hollows T1, T2 as spaces, 1st and 2nd transmission mechanisms X1, X2, ... 1st, 2nd axes 5, 8, 9 ... 1st, 2nd and 3rd transmission members 6 ... Eccentric rotating member 6j ... Main shaft part 6ja ... Inner end part 6e ... Eccentric shaft parts 8a, 8b ... First and second half bodies 8c ...・ Connecting member

Claims (2)

A first transmission member (5) supported by the case (C) so as to rotate together with the differential case (C) and rotatable about a first axis (X1);
A main shaft portion (6j) rotatable around the first axis (X1) and an eccentric shaft portion (6e) having a second axis (X2) eccentric from the first axis (X1) as a 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) disposed opposite to the second transmission member (8) and supported around the differential case (C) and rotatable about the first axis (X1);
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);
The main shaft portion (6j) has a first spline boss (SB1) for spline fitting (16) the first drive shaft (S1), and the third transmission member (9) has a second drive shaft ( Differential devices each including a second spline boss (SB2) for spline fitting (17) to S2),
The second transmission member (8) is rotatably supported by the eccentric shaft portion (6e) and is opposed to the first transmission member (5), and a first half (8a) and a first half ( 8a) having a second half (8b) opposed across the space (SP) and a connecting member (8c) for integrally connecting the first and second halves (8a, 8b). The first transmission mechanism (T1) between the first half (8a) and the first transmission member (5), and the second half (8b) and the third transmission member (9). The second speed change mechanism (T2) is provided between
The first spline boss (SB1) is disposed such that its inner end (6ja) projects into the space (SP) between the first and second halves (8a, 8b). Features a differential.   The space (SP) has a center of gravity opposite to the total center of gravity (G) of the eccentric shaft portion (6e) and the second transmission member (8) and is connected to the first spline boss (SB1). The differential device according to claim 1, wherein a balance weight (W) is arranged.

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