JP2017141929A - Transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To axially position a transmission shaft relatively to a casing without providing special positioning means while making the casing thin and lightweight by receiving a thrust load that is generated in a transmission mechanism, as a tension load of a single transmission shaft in a transmission device comprising: a first transmission member defining a first axis as the center axis; a shaft member in which a first transmission shaft, which is rotated around the first axis, and an eccentric shaft part, defining a second axis eccentric from the first axis as the center axis, are connected together; a second transmission member which is supported in a freely rotatable manner by the eccentric shaft part; a third transmission member which is coaxially connected to a second transmission shaft which is rotated around the first axis; 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 first transmission member 5 is adjacently disposed on one sidewall Ca of a casing C, and first to third transmission members 5, 8 and 9 are held together with the one sidewall Ca of the casing C by first and second hold members that are fixed on a first transmission shaft.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transmission device, in particular, a first transmission member having a first axis as a central axis, a first transmission shaft rotating around the first axis, and an eccentric having a second axis eccentric from the first axis as a central axis. A shaft member integrally connected to the shaft portion, a second transmission member that is rotatably supported by the eccentric shaft portion and that faces the first transmission member, and a second transmission shaft that has the first axis as the central axis. And a third transmission member that is coupled to the second 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. In addition, a second transmission mechanism capable of transmitting torque while accommodating the first to third transmission members so as to be rotatable about the first axis, and a casing to which the first transmission member is connected so as not to be relatively rotatable. It relates to a transmission device.

  The transmission device is conventionally known as disclosed in, for example, Patent Document 1. In this device, the first speed change mechanism is located on a surface of the first transmission member facing the second transmission member, and the first axis is arranged. A second corrugated annular first transmission groove and a second transmission member on a surface facing the first transmission member, the second transmission member being a corrugated annular centered on the second axis and having a wave number different from the first transmission groove. A plurality of first transmission gears and a plurality of first transmission gears that are interposed at a plurality of intersecting portions of the first and second transmission grooves and perform the transmission between the first and second transmission members while rolling the first and second transmission grooves. A third transmission groove that is on the surface of the second transmission member facing the third transmission member and that is centered on the second axis, and the second transmission mechanism has a first rolling element. A fourth wave member having a wave shape centered on the first axis and having a wave number different from that of the third transmission groove is on the surface of the member facing the second transmission member. A plurality of second transmission gears that are interposed at a plurality of intersections of the driving groove and the third and fourth transmission grooves, and that perform transmission transmission between the second and third transmission members while rolling the third and fourth transmission grooves. 2 rolling elements. And in this structure, there exists an advantage which can attain flat miniaturization of the axial direction of a transmission device, for example by comprising each transmission member in plate shape.

JP 2003-172419 A JP 2009-24765 A

  By the way, in the conventional transmission apparatus as shown by patent document 1, it becomes a structure which supports the thrust load which generate | occur | produces in a 1st, 2nd transmission mechanism with the both side walls of the casing which accommodates a 1st-3rd transmission member. Yes. For this reason, it is necessary to set the thickness of each part to be thick enough to withstand the thrust load, and there is a disadvantage in that the casing, and thus the entire transmission device, is increased in weight.

  In the rolling ball type transmission shown in FIG. 9 of Patent Document 2, the thrust load generated by the ball transmission mechanism between the transmission members is supported on one transmission shaft. The casing of the mechanism simply supports the input / output shafts connected to the input / output transmission members in the casing so as to be rotatable on both side walls, and the axial positioning of the input / output shafts relative to the casing A special positioning means for performing the above is required. Therefore, not only the structure of the transmission device is complicated, but also there is a possibility that some amount of axial backlash occurs between the casing and the input / output shaft, which may cause noise.

  The present invention has been made in view of such circumstances, and is capable of firmly receiving the thrust load generated by the first and second transmission mechanisms as a tensile load of a single shaft member (first transmission shaft). Accordingly, it is an object of the present invention to provide a transmission device capable of accurately positioning the transmission shaft with respect to the casing in the axial direction without providing any special positioning means while reducing the thickness and weight of the casing.

  To achieve the above object, the present invention is centered on a first transmission member having a first axis as a central axis, a first transmission shaft rotating around the first axis, and a second axis eccentric from the first axis. A shaft member integrally connecting an eccentric shaft portion serving as an axis, a second transmission member rotatably supported by the eccentric shaft portion and opposed to the first transmission member, and a first axis having the first axis as a central axis A third transmission member that is coaxially connected to the two transmission shafts and faces the second transmission member; a first transmission mechanism that is capable of transmitting torque while shifting between the first and second transmission members; A second transmission mechanism capable of transmitting torque while shifting between the second and third transmission members, and the first and second transmission shafts so as to be rotatable about a first axis, and the first transmission member is relatively rotated. A casing that is impossiblely connected, and the first speed change mechanism A corrugated annular first transmission groove on the surface facing the second transmission member of the first transmission member and centering on the first axis, and a surface facing the first transmission member of the second transmission member The second transmission groove 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 intersecting portions of the first and second transmission grooves. A plurality of first rolling elements that perform transmission transmission between the first and second transmission members while rolling the two transmission grooves, and the second transmission mechanism includes the third transmission member of the second transmission member. A wavy annular third transmission groove on the surface facing the transmission member and centering on the second axis, and a surface of the third transmission member on the surface facing the second transmission member and centering on the first axis And a fourth transmission groove having a wave number different from that of the third transmission groove and a plurality of intersecting portions of the third and fourth transmission grooves. And a plurality of second rolling elements for performing transmission transmission between the second and third transmission members while rolling the third and fourth transmission grooves, and performing transmission transmission between the first and second transmission shafts. Or a transmission device that distributes rotational torque from the casing to the first and second transmission shafts, wherein the first transmission member is disposed adjacent to one side wall of the casing, and the first transmission The first feature is that the first, second, and third transmission members are clamped together with the one side wall of the casing by first and second clamping members fixed on the shaft.

  According to the present invention, in addition to the first feature, an outer surface of the third transmission member disposed so as to be rotatable relative to the first transmission shaft is supported by the second clamping member via a thrust bearing, The second transmission shaft is splined to the third transmission member, and a space for accommodating the thrust bearing and the second clamping member is provided between the second transmission shaft and the third transmission member. The second feature.

  According to the present invention, in addition to the first or second feature, a motor case for housing and supporting a stator of an electric motor is integrally connected to the one side wall of the casing, and the rotor of the electric motor is connected to the first side. A third feature is that the first clamping member is fixed to one transmission shaft.

  According to the present invention, in addition to the third feature, the second transmission shaft is supported on the other side wall of the casing via the first bearing, and is axially inward from the first bearing. A wheel is attached to a portion of the second transmission shaft that extends outward from the first bearing and is supported by an inner wall of the intermediate portion of the casing via a second bearing spaced apart from the first bearing. Features.

  According to the present invention, in addition to the fourth feature, the second transmission shaft includes a cylindrical shaft that is spline-fitted to the third transmission member, and an inner end portion is press-fitted into an inner peripheral surface of the cylindrical shaft. A fifth feature is that a mounting portion of the wheel is provided in a portion of the shaft main body that extends outward from the first bearing.

  According to the first feature of the present invention, the first and second clamping members are disposed adjacent to one side wall of the casing that houses the first to third transmission members, and are fixed on the first transmission shaft. Since the first to third transmission members are held together with the one side wall of the casing by the member, the tensile load generated by the first and second transmission mechanisms is applied to the single shaft member (particularly the first transmission shaft) as a tensile load. As such, it can be taken firmly by itself. As a result, the thrust load does not act to separate the side walls of the casing, and the load on the casing is reduced accordingly. can do. In addition, the one side wall of the casing adjacent to the first transmission member is clamped by the first and second clamping members on the first transmission shaft together with the first to third transmission members, so that the axial direction of the first transmission shaft with respect to the casing Positioning can be performed accurately without play without providing any special positioning means, which can contribute to simplification of the structure of the transmission and prevention of noise generation.

  According to the second feature of the present invention, the outer surface of the third transmission member that can rotate relative to the first transmission shaft is supported by the second clamping member via the thrust bearing. A thrust load from the third transmission member can be supported by the second clamping member while ensuring a smooth relative rotation between the third transmission members. In addition, the second transmission shaft is spline-fitted to the third transmission member, and a space for accommodating the thrust bearing and the second clamping member is provided between the second transmission shaft and the third transmission member. 2 With the transmission shaft separated from the third transmission member, the thrust bearing and the second clamping member can be easily attached to and detached from the first transmission shaft. And since the spline fitting of the second transmission shaft to the third transmission member becomes possible without being obstructed by the second clamping member, the assembly workability is good.

  According to the third aspect of the present invention, a motor case for housing and supporting the stator of the electric motor is integrally connected to the one side wall of the casing, and the rotor of the electric motor is first connected to the first transmission shaft. Since it is fixed with the clamping member, a transmission device is obtained in which the electric motor that drives the first transmission shaft is unitized. In this case, since the first clamping member is also used as a fixing means for fixing the rotor of the electric motor to the first transmission shaft, it can contribute to further simplification of the structure of the apparatus.

  According to the fourth feature of the present invention, the second transmission shaft is supported on the other side wall of the casing via the first bearing, and is separated from the first bearing inward in the axial direction. Since the wheel is attached to a portion of the second transmission shaft that extends outward from the first bearing, supported by the inner wall of the casing through the bearing 2, the compact wheel using an electric motor as a drive source A drive transmission is obtained. In this case, the second transmission shaft functions as an axle and is supported by the casing via the first and second bearings spaced apart from each other (that is, with a long support span). 2 Support rigidity of the transmission shaft can be increased.

  According to a fifth aspect of the present invention, the second transmission shaft includes a cylindrical shaft that is spline-fitted to the third transmission member, and a shaft main body whose inner end is press-fitted into the inner peripheral surface of the cylindrical shaft. And the wheel mounting portion is provided in a portion of the shaft main body that extends outward from the first bearing, so that the spline on the second transmission shaft side is a separate component from the shaft main body and relatively It is formed on a cylindrical shaft that is a small part, and the workability of the spline is good. Further, since the cylinder shaft and the shaft main body are press-fitted and coupled, when an overload is applied to the wheel, the electric motor can be protected from the overload by causing the press-fit portion to slip.

1 is a longitudinal sectional view showing an example of a power unit for a motorcycle including a transmission device (reduction gear) according to an embodiment of the present invention. The principal part expanded sectional view of the said embodiment (2 arrow part enlarged view of FIG. 1) 3-3 arrow sectional view of FIG. 4-4 cross-sectional view of 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 4 will be described. In FIG. 1, a power unit P of a motorcycle includes an electric motor M as a drive source and a speed reducer R as a transmission device that decelerates the driving force and transmits it to the wheels (rear wheels W). The power unit P is mounted on the rear end of a swing arm (not shown) that is pivotally supported on the motorcycle body so as to swing up and down so that it can swing together with the swing arm.

  In the power unit P, the speed reducer R decelerates the rotation of the first transmission shaft S1 that also serves as the output shaft of the electric motor M via the first and second transmission mechanisms T1 and T2 and transmits the reduced speed to the second transmission shaft S2. In this case, the rear wheel W is coupled to the second transmission shaft S2 so as to rotate integrally. The first and second transmission shafts S1 and S2 rotate around the first axis X1 through the pair of first and second bearings B1, B1 '; B2, B2' in the unit case Pc of the power unit P, respectively. Supported as possible.

  The electric motor M includes a motor case 1, a stator 2 fixed to the inner surface of the outer peripheral wall of the case 1, and a rotor 3 located inside the stator 2 and fixed to the first transmission shaft S <b> 1. The motor case 1 is divided into two parts, for example, a bottomed cylindrical case body and a lid that closes its open end.

  The speed reducer R cooperates with the motor case 1 to form a hollow casing C that constitutes a unit case Pc of the power unit P, and first, second, and second housings that are accommodated in the casing C in an axial state in series. 3 transmission members 5, 8, 9; shaft member J integrally including the first transmission shaft S1 and the eccentric shaft portion 6e protruding integrally from the outer periphery of the intermediate portion of the shaft S1, and the first and second transmission members 5 , 8 is a first transmission mechanism T1 capable of transmitting torque while shifting, and a second transmission mechanism T2 capable of transmitting torque while shifting between the second and third transmission members 8 and 9 is a main component. .

  In particular, in the present embodiment, the electric motor M is coupled to the speed reducer R on the same axis (first axis X1), and the casing C and the motor case 1 of the speed reducer R are combined and integrated. The adjacent end portions of each other are fastened by a plurality of bolts 10. In this fastened state, one side wall 1a of the motor case 1 separates the internal spaces of the speed reducer R and the electric motor M, and also functions as one side wall Ca of the casing C of the speed reducer R. Then, both end portions of the first transmission shaft S1 are rotatably supported by one side wall Ca of the casing C and the other side wall 1b of the motor case 1 via first bearings B1 and B1 ′ (for example, ball bearings), respectively. The

  The first bearing B1 near the speed reducer R is engaged and supported at the inner end of the outer race 4o in the axial direction by an annular engagement step 55 projecting from the inner periphery of the one side wall Ca of the casing C. . The inner race 4i of the first bearing B1 is adjacent to the rotor 3 of the electric motor M with the collar 40 interposed therebetween, and the first bearing B1, the collar 40, and the rotor 3 are intermediate steps of the first transmission shaft S1. 56 and the first nut N1 screwed into the outer end of the shaft S1 is clamped and fastened. The first nut N1 constitutes a first clamping member. An annular seal member 11 is interposed between one side wall Ca of the casing C and the outer periphery of the collar 40. An annular seal member 41 is also interposed between the inner periphery of the collar 40 and the first transmission shaft S1.

  The first transmission member 5 is disposed adjacent to the inner surface of the one side wall Ca of the casing C with the first axis X1 as the central axis. The outer peripheral portion of the first transmission member 5 is connected to the inner peripheral surface of the outer peripheral wall of the casing C so as to rotate integrally (spline fitting SP1). In addition, as a connection means between the 1st transmission member 5 and the casing C, it may replace with spline fitting like this embodiment, and may use meshing means, such as a dog tooth and a clutch tooth. Further, a gap adjusting shim 12 is interposed between the opposing surfaces of the inner surface Ca of the casing C and the outer surface of the first transmission member 5.

  The shaft member J has a first transmission shaft S1 which is a main portion of the shaft member J, the first axis X1 being a central axis, and an eccentric shaft portion 6e integrally projecting from the outer periphery of the intermediate portion of the first transmission shaft S1. The second axis line X2, which is offset from the first axis line X1 by the amount of eccentricity e, is arranged as the central axis line. The eccentric shaft portion 6e supports the inner peripheral portion of the annular second transmission member 8 via the third bearing B3 (for example, a ball bearing) so as to be rotatable around the second axis X2, and the second One side surface of the second transmission member 8 faces the inner side surface of the first transmission member 5.

  The third transmission member 9 is coaxially connected to the second transmission shaft S2 that rotates about the first axis X1, as will be described later. The inner side surface of the third transmission member 9 faces the other side surface of the second transmission member 8.

  Thus, the second transmission member 8 rotates about the second axis X2 relative to the eccentric shaft 6e as the shaft member J (particularly the first transmission shaft S1) rotates about the first axis X1, while rotating about the second axis X2. Revolve around the first axis X1 with respect to one transmission shaft S1.

  By the way, in this embodiment, the position of the total gravity center of the shaft member J and the 2nd transmission member 8 is unevenly distributed in the position spaced apart from the 1st axis line X1 to the 2nd axis line X2. Therefore, when the second transmission member 8 revolves while rotating as described above, the centrifugal force of the eccentric rotation system acts in a specific direction (on the offset side of the second axis X2) with respect to the first axis X1. The rotation of the eccentric rotation system is in an unbalanced state, but in order to eliminate or reduce the unbalanced state, a rotation radius that is opposite in phase to the total center of gravity and larger than the rotation radius of the total center of gravity. The balance weight 7 is connected to the first transmission shaft S1 integrally.

  The second transmission shaft S2 includes a long shaft main body 13 that also serves as an axle in the present embodiment, and a cylindrical shaft 14 that is fixed (press-fitted in the present embodiment) to the outer periphery of the inner end portion of the shaft main body 13. The outer end portion 13o of the shaft body 13 is a wheel mounting portion having a spline groove on the outer periphery, and a wheel hub Wh of the rear wheel W is detachably coupled to the wheel body Wh by fastening means such as a nut n and the like so as not to be relatively rotatable. Has been.

  The second transmission shaft S2 has a first axis line through a pair of second bearings B2 and B2 '(for example, a ball bearing and a roller bearing) on the inner wall of the casing C in the intermediate portion of the shaft body 13 and the cylindrical shaft 14. It is supported rotatably around X1. Of the second bearings B2 and B2 ′, the outer second bearing B2 is mounted on the inner peripheral portion of the other side wall Cb of the casing C, and the inner second bearing B2 ′ is the outer second bearing B2 ′. It is mounted on the inner peripheral wall of the intermediate part of the casing C at a position spaced inward in the axial direction from the bearing B2. Accordingly, the outer end portion 13o of the shaft body 13 extending outward from the outer second bearing B2 is the wheel mounting portion. An annular seal member 15 is interposed between the inner periphery of the casing C and the outer periphery of the shaft body 13 between the second bearings B2 and B2 ′.

  Further, the outer periphery of the inner end portion of the cylindrical shaft 14 is spline-fitted SP2 so as to be freely movable in the radial direction on the inner peripheral surface of the connecting cylindrical portion 9a projecting cylindrically on the outer surface of the third transmission member 9. In addition, in this spline fitting SP2 part, in order to permit the said smooth movement in the radial direction, some play is also set in the circumferential direction (that is, the rotational direction) within a range that does not hinder torque transmission. In addition, as a connecting means between the third transmission member 9 and the second transmission shaft S2, meshing means such as dog teeth and clutch teeth may be used instead of the spline fitting as in the present embodiment.

  The inner end portion 50 of the first transmission shaft S1 extending inward in the axial direction from the eccentric shaft portion 6e is between the opposing surfaces of the inner end surface of the second transmission shaft S2 and the outer surface of the third transmission member 9. The second nut N2 as the second clamping member is screwed onto the outer periphery of the protruding portion. In the space 51, the outer surface of the third transmission member 9 that can rotate relative to the first transmission shaft S1 (the inner end portion 50) is supported by the second nut N2 via the thrust bearing B4.

  A thrust washer 52 is provided between the second nut N2 and the thrust bearing B4. The thrust washer 52 is engaged with the inner end 50 of the first transmission shaft S1 and engages with the outer peripheral step of the inner end 50. Is done. Thus, the thrust bearing B4, the thrust washer 52, and the second clamping member N2 are accommodated in the space 51.

  Thus, the first and second transmission members 5, 8, 9 are made to be the first transmission member by the first and second nuts (N 1, N 2) fixed (screwed) on the first transmission shaft S 1. 5 is sandwiched together with one side wall Ca of the casing C adjacent to 5.

  Next, the first and second transmission mechanisms T1 and T2 will be described in order.

  On the inner surface of the first transmission member 5 facing the second transmission member 8, a wavy annular first transmission groove 21 centering on the first axis X <b> 1 is formed, and the first transmission groove 21 is illustrated in the illustrated example. Then, it extends in the circumferential direction along a hypotrochoid curve having a virtual circle centered on the first axis X1 as a base circle. On the other hand, a corrugated annular second transmission groove 22 centering on the second axis X2 is formed on one side surface 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 different from the wave number Z1 of the first transmission groove 21. Crosses the first transmission groove 21 at a plurality of locations with a wave number Z2 (for example, small). A plurality of first 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 of the first balls 23 is a first one. And the inner surface of the 2nd transmission grooves 21 and 22 can roll freely.

  Between the opposing surfaces of the first transmission member 5 and the second transmission member 8, an annular flat first holding member H1 is interposed. The first holding member H1 can maintain the engaged state of the plurality of first balls 23 in both the transmission grooves 21 and 22 at the intersections of the first and second transmission grooves 21 and 22. A plurality of circular holding holes 31 are provided to hold the plurality of first balls 23 in a freely rotating manner while keeping their mutual intervals constant.

  Further, on the other side surface of the second transmission member 8 facing the third transmission member 9, a wavy annular third transmission groove 24 centering on the second axis X2 is formed, and the third transmission groove 24 is In the illustrated example, it extends in the circumferential direction along an epitrochoid curve having a virtual circle centered on the second axis X2 as a basic circle. On the other hand, on the inner surface of the third transmission member 9 facing the second transmission member 8, a wavy annular fourth transmission groove 25 centering on the first axis X <b> 1 is formed. In the illustrated example, the fourth transmission groove 25 extends in the circumferential direction along a hypotrochoid curve having a virtual circle centered on the first axis X1 as a base circle, and is different from the wave number Z3 of the third transmission groove 24. It intersects with the third transmission groove 24 at a plurality of locations with a wave number Z4 (for example, less). A plurality of second balls 26 as second rolling elements are interposed at the intersecting portion (overlapping portion) of the third transmission groove 24 and the fourth transmission groove 25, and each second ball 26 has a third and a third one. 4 The inner surfaces of the transmission grooves 24 and 25 can roll freely.

  Between the opposing surfaces of the third transmission member 9 and the second transmission member 8, an annular flat second holding member H2 is interposed. The second holding member H2 can maintain the engagement state of the plurality of second balls 26 to the transmission grooves 24 and 25 at the intersections of the third and fourth transmission grooves 24 and 25. The plurality of second balls 26 are provided with a plurality of circular holding holes 32 for holding the second balls 26...

  Thus, the first transmission groove 21, the second transmission groove 22, and the first ball 23 constitute a first transmission mechanism T1 that cooperates with each other to perform a first-stage speed change (deceleration), and a third transmission. The groove 24, the fourth transmission groove 25, and the second ball 26 constitute a second transmission mechanism T2 that cooperates with each other to perform a second-stage speed change (deceleration).

  Next, the operation of the embodiment will be described.

  When the vehicle travels, an on-vehicle electronic control unit controls energization to the electric motor M (and hence rotation of the motor M) based on the accelerator operation of the driver. When the first transmission shaft S1 is rotationally driven by the electric motor M, the eccentric shaft portion 6e integrated therewith revolves around the first axis X1, and accordingly, the second transmission on the eccentric shaft portion 6e. The member 8 also revolves around the first axis X1. According to this revolution, both the first transmission groove 21 of the first transmission member 5 and the second transmission groove 22 of the second transmission member 8, both of which are spline-fitted into the casing C and are restricted in rotation, are connected to each other. The first balls 23 engaged at the intersections of the grooves 21 and 22 roll on the grooves 21 and 22, so that the second transmission member 8 is rotated about the second axis X2 on the eccentric shaft portion 6 e. Rotate.

  According to the rotation and revolution of the second transmission member 8, the intersection of the grooves 24 and 25 between the third and fourth transmission grooves 24 and 25 on the second and third transmission members 8 and 9. As the second balls 26 that engage with each other roll on the grooves 24 and 25, the third transmission member 9 is driven to rotate about the first axis X1. The rotation driving force is transmitted to the second transmission shaft S2 that is spline-fitted SP2 to the third transmission member 9.

  Thus, the rotation of the first transmission shaft S1 driven by the electric motor M is transmitted to the second transmission shaft S2 by decelerating to the second transmission shaft S2 through the first and second transmission mechanisms T1 and T2 in sequence, and thus the second transmission shaft S2. The wheel W can be driven to decelerate by the electric motor M.

In the rolling ball type speed reducer R as in this embodiment, 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, When the wave number of the transmission groove 25 is Z4, the reduction ratio ε between the first transmission shaft S1 (input shaft) and the second transmission shaft S2 (output shaft) is
ε = 1 − {(Z1 × Z3) / (Z2 × Z4)}
Represented as:

  In the rolling ball type reduction gear R as in the present embodiment, torque transmission between the first transmission member 5 and the second transmission member 8 is performed by the first transmission groove 21, the plurality of first balls 23, and the second transmission groove. 22, and torque transmission between the second transmission member 8 and the third transmission member 9 is performed via the third transmission groove 24, the plurality of second balls 26, and the fourth transmission groove 25. Thereby, between each of the 1st transmission member 5 and the 2nd transmission member 8, and the 2nd transmission member 8 and the 3rd transmission member 9, torque transmission is carried out to a plurality of places where the 1st and 2nd balls 23 and 26 exist. Since it is performed in a distributed manner, the strength and weight of each transmission element such as the first to third transmission members 5, 8, 9 and the first and second balls 23, 26 can be increased. Moreover, according to the transmission structure of the present embodiment, the first to third transmission members 5, 8, and 9 are each formed in a plate shape and arranged in the axial direction so that the transmission can be easily flattened in the axial direction (reduction gear R). Can be provided.

  In the present embodiment, the first, second, and third transmissions are performed by the first and second nuts N1, N2 as first and second clamping members fixed (screwed) on the first transmission shaft S1. Since the members 5, 8, and 9 are sandwiched together with the one side wall Ca of the casing C adjacent to the first transmission member 5, a single shaft member is used to generate thrust loads generated by the first and second transmission mechanisms T1 and T2. J (that is, the first transmission shaft S1) can be firmly received as a tensile load alone. That is, the outward (leftward in FIG. 2) thrust load generated by the first speed change mechanism T1 passes through the engaging step 55, the first bearing B1, the collar 40, and the rotor 3 in order from the casing one side wall Ca. On the other hand, the outward (rightward in FIG. 2) thrust load generated by the second transmission mechanism T2 is transmitted to the second nut N2 through the third transmission member 9, the thrust bearing B4, and the thrust washer 52 sequentially. Therefore, both the thrust loads act as tensile loads on both ends of the shaft member J (particularly, the first transmission shaft S1) via both nuts N1 and N2.

  As a result, the thrust loads do not act so as to separate the both side walls Ca and Cb of the casing C, and the load burden on the casing C is reduced accordingly. A reduction in size and weight of the transmission (reduction gear R) can be achieved. In addition, the casing one side wall Ca is clamped by the first and second transmission members 5, 8, and 9 by the first and second nuts N1 and N2 on the shaft member J (that is, the first transmission shaft S1). The axial positioning of the first transmission shaft S1 with respect to C can be accurately performed without play without providing any special positioning means, which is effective in simplifying the structure of the transmission device (reduction gear R) and preventing noise generation. .

  In this embodiment, since the outer surface of the third transmission member 9 is supported by the second nut N2 via the thrust bearing B4, smooth relative rotation between the first transmission shaft S1 and the third transmission member 9 is ensured. However, the thrust load from the third transmission member 9 can be received by the second nut N2. In addition, the second transmission shaft S2 is splined SP2 to the third transmission member 9, and the thrust bearing B4 and the second nut N2 are accommodated between the second transmission shaft S2 and the third transmission member 9. Since the space 51 is provided, the thrust bearing B4 and the second nut N2 are attached to and detached from the first transmission shaft S1 (inner end portion 50) with the second transmission shaft S2 separated from the third transmission member 9. Work can be easily performed, and in the mounted state, the spline fitting SP2 of the second transmission shaft S2 to the third transmission member 9 is possible without being interrupted by the thrust bearing B4 and the second nut N2. Therefore, the assembly workability is very good.

  Further, in the present embodiment, a motor case 1 that accommodates and supports the stator 2 of the electric motor M is integrally connected to the one side wall Ca of the casing C, and the rotor 3 of the motor M is first connected to the first transmission shaft S1. Since it is fixed with the nut N1, a power unit P is obtained in which the electric motor M that drives the first transmission shaft S1 and the transmission device (reduction gear R) are unitized together. In this case, since the first nut N1 is also used as a fixing means for fixing the rotor 3 of the electric motor M to the first transmission shaft S1, the structure of the device can be further simplified.

  In addition, the second transmission shaft S2 of the present embodiment is supported on the other side wall Cb of the casing C via the outer second bearing B2, and is axially inward from the outer second bearing B2. The outer end portion 13o of the second transmission shaft S2 that is supported by the inner wall of the intermediate portion of the casing C via the inner second bearing B2 'that is spaced apart from the outer end of the second transmission shaft S2 extends outward from the outer second bearing B2. Wheels W are attached. Thereby, a compact wheel driving power unit P using the electric motor M as a driving source is obtained. In this case, the second transmission shaft S2 functions as an axle, and is supported by the casing C via a pair of second bearings B2 and B2 'spaced apart from each other (that is, with a long support span). The support rigidity of the second transmission shaft S2 as the axle is increased.

  In particular, the second transmission shaft S2 includes a cylindrical shaft 14 that is spline-fitted SP2 to the third transmission member 9, and a shaft main body 13 in which an inner end portion is press-fitted into the inner peripheral surface of the cylindrical shaft 14. An outer end portion 13o extending outward from the second bearing B2 is a wheel mounting portion. Thereby, since the spline groove on the second transmission shaft S2 side is formed in the cylindrical shaft 14 which is a small component separate from the shaft main body 13, workability is good. In addition, since the cylindrical shaft 14 and the axle, that is, the shaft main body 13 are press-fitted and connected, when the wheel W is overloaded, the electric motor M can be protected from overload by causing the press-fitted portion to slip. It becomes.

  By the way, in the previous embodiment, the reduction gear R was exemplified as the transmission device, but another embodiment (not shown) is used for the rolling ball type differential device using the basic structure of the reduction gear R as it is. The assumed structure is briefly described below. In this description, the same reference numerals used in the previous embodiment are used for the same components as in the previous embodiment.

  In this other embodiment, for example, the casing C separated and independent from the motor case 1 is made to function as a differential case, which is rotatably supported by a transmission case (not shown), and a rotational driving force is input to the differential case from a drive source. For example, a pair of left and right wheels are linked to the outer ends of the first and second transmission shafts S1 and S2. The structure of the first and second speed change mechanisms T1 and T2 of this other embodiment is basically the same as the structure of the first and second speed change mechanisms T1 and T2 of the previous embodiment. Unlike the first embodiment, the transmission groove 24 is a groove extending in the circumferential direction along the hypotrochoid curve. Unlike the first embodiment, the fourth transmission groove 25 is also circumferential along the epitrochoid curve. It is a groove extending in the direction. Further, in order to use the transmission device as a differential device, when the first and second transmission mechanisms T1 and T2 rotate the casing C with the shaft member J (first transmission shaft S1) fixed, The first transmission member 5 to the third transmission member 9 are configured to be driven with a double speed increasing ratio. That is, when 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 following equation is established. As described above, the first to fourth transmission grooves 21, 22, 24, and 25 are formed.

(Z1 / Z2) × (Z3 / Z4) = 2
In this case, desirably, for example, Z1 = 8, Z2 = 6, Z3 = 6, Z4 = 4, or Z1 = 6, Z2 = 4, Z3 = 8, and Z4 = 6.

  For example, in the former case, the eight-wave first transmission groove 21 and the six-wave second transmission groove 22 intersect at seven locations, and seven first balls are formed at the seven intersection portions (overlapping portions). 23, and the six-wave third transmission groove 24 and the four-wave fourth transmission groove 25 intersect at five locations, and five second balls 26 are formed at the five intersections (overlapping portions). Is installed.

In the former case, for example, in a state where the shaft member J (and hence the eccentric shaft portion 6e) is fixed by fixing the first transmission shaft S1, the casing C (and hence the first transmission member 5) is driven by the power from the engine. When rotating around one axis X1, the eight-wave first transmission groove 21 of the first transmission member 5 drives the six-wave second transmission groove 22 of the second transmission member 8 via the first ball 23. The first transmission member 5 drives the second transmission member 8 with a speed increasing ratio of 8/6. Then, according to the rotation of the second transmission member 8, the six-wave third transmission groove 24 of the second transmission member 8 passes the four-wave fourth transmission groove 25 of the third transmission member 9 via the second ball 26. Therefore, the second transmission member 8 drives the third transmission member 9 with a speed increasing ratio of 6/4. Therefore, the first transmission member 5 is (Z1 / Z2) × (Z3 / Z4) = (8/6) × (6/4) = 2.
Thus, the third transmission member 9 (second transmission shaft S2) 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 second transmission shaft S2, the rotational driving force of the first transmission member 5 and the second Due to the driving reaction force of the transmission member 8 against the stationary third transmission member 9, the second transmission member 8 rotates about the first axis X1 while rotating about the second axis X2 relative to the eccentric shaft portion 6e of the shaft member J. And the eccentric shaft portion 6e is driven around the first axis X1. As a result, the first transmission member 5 drives the shaft member J (first transmission shaft S1) with a double speed increase ratio.

  Thus, when the loads of the shaft member J and the third transmission member 9 are balanced or changed with each other, the amount of rotation and the amount of revolution of the second transmission member 8 change steplessly, and the shaft member J And the average value of the rotation speed of the 3rd transmission member 9 becomes equal to the rotation speed of the 1st transmission member 5. FIG. Thus, the rotation of the first transmission member 5 is distributed to the shaft member J and the third transmission member 9, so that the rotational force transmitted to the differential case C can be distributed to the left and right transmission shafts S1, S2.

  Thus, according to the transmission structure of another embodiment described above, a differential device that can be easily flattened in the axial direction can be provided, and the same effects as the previous embodiments can be achieved.

  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 illustrated embodiment, as the transmission device, the one implemented in the vehicle reduction gear R for driving the motorcycle wheel (rear wheel W) with the electric motor M to reduce the speed is illustrated, but the transmission device of the present invention is exemplified. May be used for driving wheels of vehicles other than motorcycles, for example, four-wheeled vehicles, or may be used as a speed reducer for various mechanical devices other than vehicles. In either case, the drive source may be an engine or a hydraulic motor in addition to the electric motor, and the drive source case and the transmission casing are coupled as shown in the illustrated embodiment. You may integrate, or you may comprise separately. Further, when used for rear wheel driving of a motorcycle, for example, as shown in the illustrated embodiment, the drive source (electric motor) is not directly connected to the transmission device (reduction gear R), but is spaced forward from the rear wheel. The drive source may be linked to the transmission device (reduction gear R) via an endless transmission mechanism such as a chain transmission mechanism, a drive shaft mechanism, or the like.

  In the illustrated embodiment, the reduction gear R having the first transmission shaft S1 as an input shaft and the second transmission shaft S2 as an output shaft is shown as a transmission device. However, for example, the transmission device may be a first transmission shaft S1. By using the second transmission shaft S2 as the input shaft as the output shaft, the speed increasing device may be used.

  Moreover, in the said another embodiment, although the differential gear D as a transmission device is accommodated in the mission case 1 of a motor vehicle, the differential gear D is not limited to the differential gear for motor vehicles, Various The present invention can be implemented as a differential for a mechanical device.

  In the other 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, 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 embodiment, the first and second holding members H1 and H2 are configured by an annular ring having inner and outer peripheral surfaces each having a perfect circle, but the shape of the first and second holding members is as follows. The present invention is not limited to the above embodiment, and any annular body that can hold at least a plurality of first and second balls 23 and 26 at regular intervals may be used. For example, an elliptical annular body or an annular body curved in a waveform There may be. If the first and second 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 may be omitted. Good.

B2 ... Outside second bearing (first bearing)
B2 '... Inward second bearing (second bearing)
C ··· Casing Ca ··· One side wall of the casing Cb ··· The other side wall of the casing J ··· Shaft member M ··· Electric motors N1 and N2・ First and second nuts (first and second clamping members)
R ... Reducer (transmission device)
S1, S2 ··· First and second transmission shafts SP2 ··· Spline fitting T1, T2 ··· First and second transmission mechanisms W ··· Rear wheels (wheels)
X1, X2 ··· First and second axis 1 ··· Motor case 2 ··· Stator 3 ··· Rotor 5, 8, 9 ··· First, second and second 3 Transmission member 6e ··· Eccentric shaft portion 13 ··· Shaft body 13o ··· Outer end portion (part, wheel mounting portion)
14... Cylindrical shafts 21, 22... First and second transmission grooves 23, 26... First and second balls (first and second rolling elements)
24, 25 ... 3rd and 4th transmission groove

Claims (5)

A first transmission member (5) having a first axis (X1) as a central axis;
The first transmission shaft (S1) having the first axis (X1) as the central axis, and the eccentric shaft portion (6e) having the second axis (X2) eccentric from the first axis (X1) as the central axis are integrally connected. Shaft member (J),
A second transmission member (8) that is rotatably supported by the eccentric shaft portion (6e) and faces the first transmission member (5);
A third transmission member (9) which is coaxially connected to the second transmission shaft (S2) having the first axis (X1) as a central axis and which faces 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 casing (C) that supports the first and second transmission shafts (S1, S2) so as to be rotatable about a first axis (X1), and the first transmission member (5) is connected in a relatively non-rotatable manner; With
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 wave-shaped first shape centered on the first axis (X1). A first wave number is transmitted in a wave shape centered on the second axis (X2) on the surface of the transmission groove (21) and the second transmission member (8) facing the first transmission member (5). A second transmission groove (22) different from the groove (21) and a plurality of intersecting portions of the first and second transmission grooves (21, 22) are interposed between the first and second transmission grooves (21, 22). And a plurality of first rolling elements (23) that perform transmission transmission between the first and second transmission members (5, 8) while rolling
The second transmission mechanism (T2) is located on a surface of the second transmission member (8) facing the third transmission member (9) and has a waveform-shaped third centered on the second axis (X2). The wave number of the third transmission is a wave-shaped ring centered on the first axis (X1) on the surface of the transmission groove (24) and the third transmission member (9) facing the second transmission member (8). A fourth transmission groove (25) different from the groove (24) and a plurality of intersecting portions of the third and fourth transmission grooves (24, 25) are interposed between the third and fourth transmission grooves (24, 25). A plurality of second rolling elements (26) that perform transmission transmission between the second and third transmission members (8, 9) while rolling)
Transmission that performs transmission transmission between the first and second transmission shafts (S1, S2) or distributes rotational torque from the casing (C) to the first and second transmission shafts (S1, S2). A device,
The first transmission member (5) is disposed adjacent to one side wall (Ca) of the casing (C),
The first, second and third transmission members (5, 8, 9) are moved to the casing (C) by the first and second clamping members (N1, N2) fixed on the first transmission shaft (S1). ), And the one side wall (Ca). An outer surface of the third transmission member (9) disposed so as to be rotatable relative to the first transmission shaft (S1) is supported by the second clamping member (N2) via a thrust bearing (B4),
The second transmission shaft (S2) is spline fitted (SP2) to the third transmission member (9), and the thrust bearing is interposed between the second transmission shaft (S2) and the third transmission member (9). The transmission device according to claim 1, wherein a space (51) for accommodating (B4) and the second clamping member (N2) is provided.   A motor case (1) for accommodating and supporting the stator (2) of the electric motor (M) is integrally connected to the one side wall (Ca) of the casing (C), and the rotor (3) of the electric motor (M) is integrally provided. ) Is fixed to the first transmission shaft (S1) with the first clamping member (N1). The transmission device according to claim 1 or 2, wherein the first transmission shaft (S1) is fixed to the first transmission shaft (S1). The second transmission shaft (S2) is supported on the other side wall (Cb) of the casing (C) via the first bearing (B2), and is axially inward from the first bearing (B2). Supported on the inner wall of the intermediate part of the casing (C) via a second bearing (B2 ') spaced apart on the side,
4. The transmission according to claim 3, wherein a wheel (W) is attached to a portion (13 o) of the second transmission shaft (S <b> 2) that extends outward from the first bearing (B <b> 2). apparatus. The second transmission shaft (S2) has a cylindrical shaft (14) that is spline-fitted (SP2) to the third transmission member (9), and an inner end is press-fitted into the inner peripheral surface of the cylindrical shaft (14). A shaft body (13)
The attachment part (13o) of the said wheel (W) is provided in the part extended outward from the said 1st bearing (B2) of the axis | shaft main body (13), The characterized by the above-mentioned. Transmission device.

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