JPH07174201A - Friction wheel type continuously variable transmission - Google Patents

Abstract

PURPOSE:To retain the contact position between a friction wheel supporting member and a link unvariably even at the time of occurrence of a crossing angle between them to reduce the hysteresis of a speed-change characteristic. CONSTITUTION:The delivery of power is performed between the input and output cone disks on a main shaft 2 by power rollers 3. The stroke of a trunnion 4 by a piston 13 causes the oscillation-rotation of the power roller 3 to make it perform continuously variable speed change. The relative tilting between the trunnion 4 and links 5, 6 following the stroke of the trunnion 4 is performed with projections 5c and 6c as fulcrums, and the hysteresis of a speed-change control characteristic can be reduced with the contact position of both the sides retained unvariable even at the time of occurrence of the crossing angle between the trunnion 4 and the links 5, 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement proposal of a friction wheel type continuously variable transmission aiming at improvement of shift control accuracy.

[0002]

2. Description of the Related Art Generally, a friction wheel type continuously variable transmission, as described, for example, in Japanese Patent Laid-Open No. 173552/1989, uses an input / output disk coaxially opposed to each other and a frictional engagement between the input / output disks to generate power. A plurality of friction wheels arranged around the axis of rotation of the input / output disk, a friction wheel support member that rotatably supports each friction wheel, and adjacent end portions of these friction wheel support members are arranged so as to be delivered. Mutually, the friction wheel supporting member is provided with a link connected through a spherical joint so that the friction wheel supporting member is stroked in synchronization with the swing axis direction orthogonal to the rotation axis of the friction wheel. It is usual that the shift is performed by causing a tilt around the swing axis of the.

[0003]

However, in the conventional friction wheel type continuously variable transmission represented by the above, since the friction wheel supporting member and the link are correlated as shown in FIG. 8, the following problems occur. It was happening. In this figure, a indicates a friction wheel support member and b indicates a link. The friction wheel support member a is rotatably supported by a bearing c fitted to the link b, and further fitted on the bearing c. The spherical joint d is connected so as to be tiltable with respect to the link b. Incidentally, e is a link support for tiltably supporting the link b in the center of the transmission case at the center.

By the way, as shown by f in FIG. 8A, the friction wheel support member a and the link b are in plane contact with each other at a neutral position where gear shifting is not performed, so that FIGS. When the friction wheel supporting member a is stroked to perform the upshift shift or the downshift shift as shown in FIG. 5, the friction wheel supporting member a has an angle of intersection with the link b and hits the link b at the point g or h. The edge hits g and h similarly occur at the opposite end of the link b, but asymmetrically, and also occur at another link.

For this reason, the arm length between each edge contact point and the link support e is different, and this arm length also changes, and the friction wheel support member a between the spherical joint d and the link b is changed. Causes sliding in the axial direction. The resistance associated with this sliding increases the hysteresis of the gear shift control characteristic and reduces the gear shift control accuracy, as is clear from FIG. 7A showing the change state of the gear ratio with respect to the gear shift command.

According to the present invention, the contact position between the friction wheel support member and the link is kept unchanged during the stroke of the friction wheel support member, and the arm length between the contact position and the link support is made constant. Then, it aims at solving the above-mentioned problem.

[0007]

To this end, the first invention is directed to an input / output disk which is coaxially opposed to the input / output disk, and to transfer power by frictional engagement between the input / output disk. A plurality of friction wheels arranged around the axis of rotation, a friction wheel support member that rotatably supports each friction wheel, and mutually adjacent end portions of the friction wheel support member,
The friction wheel supporting member is provided with a link connected through a spherical joint so that the friction wheel supporting member is stroked in synchronization with the swing axis direction orthogonal to the rotation axis of the friction wheel. In a friction wheel type continuously variable transmission in which tilting about a swing axis is generated to perform gear shifting, a friction angle between the friction wheel supporting member and the link is maintained during a stroke of the friction wheel supporting member. Instead, the link is provided with a protrusion for keeping the contact position between the friction wheel support member and the link unchanged.

A second aspect of the invention is the same as the first aspect of the invention.
The above-mentioned projection is arranged on the outermost peripheral edge of the spherical joint on the side farthest from the adjacent friction wheel support member.

A third aspect of the invention is the same as the first aspect of the invention.
It is characterized in that the protrusion is arranged on a swing center that does not cause relative displacement between the link and the spherical joint even during a change in an intersection angle between the friction wheel support member and the link due to a stroke of the friction wheel support member. It is a thing.

[0010]

In the first aspect of the present invention, the plurality of friction wheels transfer power by frictional engagement between the input and output disks. In addition, friction wheel support members that rotatably support each friction wheel are individually
When the friction wheel is stroked in the direction of the swing axis perpendicular to the rotation axis of the friction wheel, the friction wheel is caused to swing and the transmission ratio between the input and output disks can be continuously changed. During this gear shift, the link functions to synchronize the stroke of the friction wheel support member, so that gear shift control can be accurately performed.

By the way, during the stroke of the friction wheel supporting member, a protrusion for keeping the contact position between the friction wheel supporting member and the link unchanged regardless of the angle of intersection between the friction wheel supporting member and the link. Since the friction wheel supporting member is provided on the link, the link and the link are constantly in contact with each other by the above protrusion during the stroke of the friction wheel supporting member to keep the contact position unchanged, and the arm length between the contact position and the link support is fixed. Can be

Therefore, it is less likely that the friction wheel supporting member slides in the axial direction between the spherical joint and the link during gear shifting, which has occurred in the conventional friction wheel type continuously variable transmission. It is possible to reduce the hysteresis of the shift control characteristic.

Further, in the second invention, since the protrusion in the first invention is arranged on the outermost peripheral edge of the spherical joint on the side farthest from the adjacent friction wheel supporting member, the protrusion is a spherical surface to be formed on the link. It is possible to eliminate the adverse effect that the workability of the hole is deteriorated due to the presence of the projection when the spherical joint fitting hole is processed, without affecting the joint fitting hole.

Further, in a third aspect of the present invention, the swing center on which the relative displacement between the link and the spherical joint does not occur even when the angle of intersection between the friction wheel supporting member and the link changes with the stroke of the friction wheel supporting member, Since the protrusion in the first invention is arranged, the invariable contact position between the friction wheel supporting member and the link provided by the protrusion exists on the swing center, and as a result, theoretically, the spherical surface. The sliding of the friction wheel supporting member in the axial direction between the joint and the link is completely eliminated, and the hysteresis of the shift control characteristic can theoretically be zero.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 to 3 show an embodiment of a friction wheel type continuously variable transmission according to the present invention. In FIG. 1, 1 is a transmission case, 2 is a main shaft, 3 is a main shaft 2, and the main shaft 2 is sandwiched between them. It is a pair of power rollers (friction wheel) arranged as.

Although not shown, an input / output cone disk (disk) is rotatably supported on the main shaft 2 so as to face each other, the input cone disk is drivingly coupled to the power source, and the output cone disk is drivingly coupled to the output shaft. To do. Power roller 3
Transmits the power by frictional engagement between the input and output cone disks, which supports each power roller 3 rotatably on each trunnion (friction wheel support member) 4.

Each trunnion 4 is supported on the transmission case 1 by an upper link 5 and a lower link 6. Therefore, a through hole 5a is formed in the center of the upper link 5 as shown in FIGS. 2 (a) and 2 (b), and the upper link 5 is swingably supported on the transmission case 1 by a link support 7 that is spherically fitted into the through hole 5a. Then, a through hole 6a is formed in the center of the lower link 6 as shown in FIGS. 3 (a) and 3 (b), and spherical fitting is performed on the through hole 6a so that the lower link 6 can be swung on the transmission case 1 by the link support 8. To support.

Then, through holes 5b are bored at both ends of the upper link 5 as shown in FIGS. 2 (a) and 2 (b), respectively, and a spherical joint 9 spherically fitted therein and a bearing 10 fitted in the spherical joint. The upper ends of both trunnions 4 are swingably and rotatably supported on both ends of the upper link 5, respectively, via.

Further, both ends of the lower link 6 are shown in FIG.
As shown in (a) and (b), the through holes 6b are bored, and the lower ends of both trunnions 4 are connected to the lower links 6 via a spherical joint 11 spherically fitted to these and a bearing 12 fitted inside the spherical joint.
Both ends of each are supported swingably and rotatably.

The rotation axis of each trunnion 4 defined by the bearings 10 and 12 is orthogonal to the rotation axis of the power roller 3.

At the lower end of each trunnion 4, a piston 1 is further provided.
3 are coaxially connected, and these pistons are simultaneously stroked in opposite directions by the control valve 14 to perform a well-known speed change control, and the links 5 and 6 compensate for the synchronization of the strokes of both trunnions. And

In this example, as also shown in FIG. 1, as clearly shown in FIGS. 2 and 3, on the periphery of the spherical joint fitting holes 5b, 6b of the upper link 5 and the lower link 6,
The protrusions 5c, 6 are provided on the side opposite to the adjacent spherical joint fitting hole.
c, and these protrusions are shown in FIGS. 2 (b) and 3 respectively.
As shown in (b), the links 5 and 6 are extended in the width direction.

Here, the reason why the projections 5c and 6c are set at such positions is as follows. That is, in the assembled state of the friction wheel type continuously variable transmission, the power roller 3 is pinched between the input and output cone disks, and a force as indicated by α in FIG. 4 is applied to the spherical joints of the links 5 and 6 via the trunnion 4. Holes 5b, 6
b, and as a result, the stress distribution to the spherical joint fitting holes 5b and 6b becomes as shown by β, so that the links 5, 6 and the spherical surface can be changed even when the crossing angle between the trunnion 4 and the links 5, 6 is changed. A swing center that does not cause relative displacement between the joints 9 and 11 exists at a position indicated by δ inside the left and right end positions of the spherical joints 9 and 11 in the figure. In view of the object of the present invention, the projections 5c and 6c are preferably located near the swing center δ.
This is the reason why c and 6c are set to the above positions.

According to the positions of the protrusions 5c and 6c in this example, these protrusions do not hang on the spherical joint fitting holes 5b and 6b, and when the spherical joint fitting holes 5b and 6b are cut,
It is preferable because the workability can be prevented from being lowered.

By the way, such spherical joint fitting holes 5b, 6
When a decrease in the machinability of b is allowed,
Further, as shown in FIG. 6, it is functionally optimal that the projections 5c and 6c are located on the swing center δ in FIG.

The operation of the above embodiment will be described below. In FIG. 1, the power roller 3 is rotated so as to transfer power between input / output cone disks (not shown) on the main shaft 2,
When the trunnion 4 is stroked in the same phase in synchronization with the direction of the swing axis orthogonal to the power roller rotation axis by the transmitting piston 13, the power roller 3 is offset from the main shaft 2 and is divided by the circumference of the swing axis. Receive power,
It is swung about the axis. As a result, the power roller 3 continuously changes the diameter of the frictional engagement circle with respect to the input / output cone disc, and the transmission ratio between the input / output cone discs,
That is, the gear ratio can be changed steplessly. Then, when the gear ratio reaches a predetermined ratio, the piston 13 causes the power roller 3 to return to the stroke position where the offset from the cone disc rotation axis becomes 0 through the trunnion 4 by known feedback control.
The predetermined gear ratio is maintained.

By the way, during the above-mentioned stroke of the trunnion 4 which is carried out during such a shift, regardless of the angle of intersection between the trunnion 4 and the upper link 4 and the lower link 6, they continue to contact at the protrusions 5c, 6c, and these protrusions 5c. , 6c as a fulcrum, it relatively tilts. Therefore, during the above stroke of the trunnion 4, the contact position between the trunnion 4 and the upper link 5 and the lower link 6 is kept unchanged regardless of the intersection angle between the upper link 5 and the lower link 6. The arm length between the contact position and the link supports 7 and 8 can be made constant.
Therefore, during gear shifting, sliding of the spherical joints 9 and 11 and the links 5 and 6 in the trunnion axial direction is less likely to occur, and the positions of the protrusions 5c and 6c can be changed as shown in FIGS. In combination with the determination in the vicinity of the swing center δ in Fig. 7, the hysteresis of the shift control characteristic can be made significantly smaller than that of the conventional one shown in Fig. 7 (a), as shown in Fig. 7 (b). it can.

When the positions of the protrusions 5c and 6c are determined on the swing center δ of FIG. 4 as shown in FIGS. 5 and 6,
Theoretically, the spherical joints 9 and 11 and the link 5,
It is possible to hardly cause sliding between 6 and 6 in the trunnion axis direction, and it is possible to further reduce the hysteresis of the shift control characteristic.

[0029]

As described above, the friction wheel type continuously variable transmission according to the first aspect of the present invention, as described in claim 1, during the stroke of the friction wheel supporting member performed at the time of gear shifting, the friction wheel supporting member and these friction wheel supporting members. The protrusions for keeping the contact position between the friction wheel supporting member and the link unchanged regardless of the angle of intersection between the adjacent end portions of the friction wheel supporting member and the link are formed. In the meantime, this and the link are always brought into contact with each other by the above-mentioned projection, and the contact position is kept unchanged, and the arm length between the contact position and the link support can be made constant.

Therefore, during shifting, it is less likely that the friction wheel supporting member slides in the axial direction between the spherical joint and the link, which has occurred in the conventional friction wheel type continuously variable transmission. It is possible to reduce the hysteresis of the shift control characteristic.

Further, in the second invention, since the projection in the first invention is arranged on the outermost peripheral edge of the spherical joint on the side farthest from the adjacent friction wheel supporting member, the projection is formed on the spherical surface. It is possible to eliminate the adverse effect that the workability of the hole is deteriorated due to the presence of the projection when the spherical joint fitting hole is processed, without affecting the joint fitting hole.

Furthermore, a third aspect of the present invention is such that, even during a change in an intersection angle between the friction wheel supporting member and the link due to a stroke of the friction wheel supporting member, a relative displacement between the link and the spherical joint does not occur on a swing center, Since the protrusion in the first invention is arranged, the invariable contact position between the friction wheel supporting member and the link provided by the protrusion exists on the swing center, and as a result, theoretically, the spherical surface. The sliding of the friction wheel supporting member in the axial direction between the joint and the link is completely eliminated, and the hysteresis of the shift control characteristic can theoretically be zero.

[Brief description of drawings]

FIG. 1 is a cross-sectional front view showing an embodiment of a friction wheel type continuously variable transmission according to the present invention.

FIG. 2A is a vertical sectional side view of an upper link in the same example, and FIG. 2B is a bottom view of the same.

3A is a longitudinal side view of a lower link in the same example, and FIG. 3B is a plan view thereof.

FIG. 4 is a plan view of a link showing a stress distribution from the trunnion to the link in the friction wheel type continuously variable transmission.

5A is a vertical sectional side view of an upper link showing another example of the present invention, and FIG. 5B is a bottom view thereof.

FIG. 6A is a longitudinal side view of a lower link in the same example, and FIG. 6B is a plan view thereof.

7A is a diagram showing a shift control characteristic of a conventional friction wheel type continuously variable transmission, and FIG. 7B shows a shift control characteristic of the friction wheel type continuously variable transmission shown in FIGS. It is a diagram.

FIG. 8 is an operation explanatory view of a conventional friction wheel type continuously variable transmission.

[Explanation of symbols]

1 Transmission case 2 Spindle 3 Power roller (friction wheel) 4 Trunnion (friction wheel support member) 5 Upper link 5 _C protrusion 6 Lower link 6 _C protrusion 7 Link support 8 Link support 9 Spherical joint 10 Bearing 11 Spherical joint 12 Bearing 13 piston

Claims (3)

[Claims] 1. An input / output disk that is coaxially opposed to each other, and a plurality of friction wheels that are arranged around a rotation axis of the input / output disk so as to transfer power by frictional engagement between the input / output disks. The friction wheel support member that rotatably supports each friction wheel and the adjacent end portions of the friction wheel support member are synchronized with each other in the swing axis direction orthogonal to the rotation axis of the friction wheel. And a link connected through a spherical joint so that the gear can be shifted by a stroke, and the stroke of the friction wheel supporting member causes a tilt around the swing axis of the friction wheel to perform gear shifting. In a continuously variable transmission, a protrusion for keeping the contact position between the friction wheel support member and the link unchanged during the stroke of the friction wheel support member regardless of the intersection angle between the friction wheel support member and the link. , Friction wheel continuously variable transmission, characterized in that provided in the link. 2. The friction wheel type continuously variable transmission according to claim 1, wherein the projection is arranged on a peripheral edge of the spherical joint farthest from an adjacent friction wheel supporting member. 3. The swing center according to claim 1, wherein a relative displacement between the link and the spherical joint does not occur even during a change in an intersection angle between the friction wheel supporting member and the link due to a stroke of the friction wheel supporting member. A friction wheel type continuously variable transmission characterized in that the protrusions are arranged.