WO1998036191A1

WO1998036191A1 - Stepless transmission mechanism

Info

Publication number: WO1998036191A1
Application number: PCT/KR1998/000025
Authority: WO
Inventors: Hyung Ik Son; Chul Hyung Cho
Original assignee: Kuku Industries, Ltd.
Priority date: 1997-02-14
Filing date: 1998-02-11
Publication date: 1998-08-20

Abstract

In a stepless transmission, a driving axis (1) receives a rotational force from an engine, a motor or a rotating apparatus. A first speed-changing portion (110) primarily changes a rotational velocity transferred from the driving axis (1). A second speed-changing portion (120) provides a driving power of various rotation ratios to a driven axis (24) by combining the rotational velocity transferred from the first speed-changing portion (110) with the rotational velocity transferred from the driving axis (1).

Description

STEPLESS TRANSMISSION MECHANISM

Technical Field

The present invention relates to a stepless transmission capable of transmitting different rotational velocities from an engine or motor without shifting, and more particularly, to a stepless transmission capable of transmitting different rotational velocities including a reverse rotational velocities using the frictional force of rotating balls.

Background Art

In a conventional lever-type transmission, since a driver manually changes speed using a shift lever, the transmission mechanism does not operates smoothly. Further, since other necessary mechanisms such as a clutch are required, the structure of the transmission complicated and thus costs for manufacture thereof are high.

In addition to the above problems, since the velocity ratios are defined into several steps, transfer of rotational force is required to be temporarily discontinued. Also, the complicated transmission means increases the defect rate.

To overcome the above disadvantages, an automatic clutchless transmission using a fluid has been developed. However, the automatic clutchless transmission has problems of its own. First, there is a great loss in the engine output while climbing elevated slopes. The clutchless transmission is large and heavy increasing the total weight of a vehicle adopting the same, which has an adverse effect on fuel efficiency. Also, the structure of the clutchless transmission is complicated and the parts thereof are expensive.

Disclosure of the Invention

To solve the above problems, it is a first object of the present invention to provide a stepless transmission in which a temporary separation of an engine from a transmission for changing speed, is not required.

It is a second object of the present invention to provide a stepless transmission capable of changing speeds and/or the direction of rotation with an odd- or even- number of rotating balls linearly assembled in a cylinder and a frictional force between a driving plate and a driven plate.

It is a third object of the present invention to provide a stepless transmission that is lightweight and has a simple structure so that a loss in an engine output can be prevented.

To achieve the above objects there is provided a stepless transmission comprising a driving axis receiving a rotational force from an engine or a motor, a first speed-changing portion for changing the rotational velocity of a driving plate combined to said driving axis, and a second speed-changing portion for providing a driving power of various rotation ratios to a driven axis by combining the rotation speed transferred from the first speed-changing portion with the rotation speed transferred from the driving axis.

The first speed-changing portion comprises a driving plate having a groove of which an arc-shaped profile is formed on the inner surface of the driving plate around the driving axis, in the first and second preferred embodiments, and spline-coupled to a driving plate confining groove formed on an appropriate position of the driving axis, a driven plate having the same groove as that of the driving plate and disposed to face the inner surface of the driving plate, a cylinder installed between the driving plate and the driven plate, rotating balls assembled together to stay together and rotate with friction inside the cylinder and roll on the surface of the groove formed on the inner surfaces of the respective driving plate and the driven plate, a coupling ring adjusting means for changing the rotation velocity of the driving axis by controlling the inclination or position of the cylinder with respect to the driving axis, an elastic supporting means, installed between the driving plate and a first fixed plate, which is fixed to the driving axis between the engine and the driving plate, for elastically supporting the driving plate, and a second fixed plate fixed to a driven axis contacting the outer surface of the driven plate by means of bearings interposed therebetween.

In a first preferred embodiment, the elastic supporting means is a leaf spring, having one end contacting fixed plate and the other end contacting the side surface of a supporting plate which will be described later, for elastically supporting the driving plate. Also, the supporting plate is disposed in a circular indentation formed on the outer surface of the driving plate. Here, the surface of the supporting plate does not contact the surface of the indentation so that a chamber is formed therebetween. The chamber is sealed by a seal ring interposed between the outer circumferential surface of the supporting plate and the inner circumferential surface of the indentation. An inlet for injecting oil for generating a hydraulic pressure is formed at the supporting plate so that oil can be supplied to the inside of the chamber from the outside. Since a seal member acting as a check valve for allowing a flow of oil in one direction is provided at the inlet, oil for generating a hydraulic pressure can be supplied from the outside. The oil together with the leaf spring supports by pressing the driving plate in the chamber.

In the second preferred embodiment, a coil spring is used as the elastic supporting means. Also, in the first preferred embodiment, the coupling ring adjusting means comprises a cylinder coupling ring, a coupling ring adjustment nut coupled to the outer circumference of the cylinder coupling ring, a coupling ring adjustment screw screw-coupled to the coupling ring adjustment nut, an outside gear coupled to the inner circumferential surface of the cylinder coupling ring, and an inside gear of a cylindrical shape having a geared portion formed on its outer circumferential surface, centered about the driving axis by being supported by bearings with respect to the outer circumferential surface of the driving axis to face the outside gear. The outside gear and the inside gear are separated to face each other by a cylinder interposed therebetween. The cylinder has a cylinder rotation gear and a circular gear on its outer circumferential surface so as to be engaged with the outside gear and the inside gear, respectively. Also, the coupling ring adjusting means according to the second preferred embodiment comprises a cylinder coupling ring, a coupling ring adjustment nut coupled to the outer circumference of the cylinder coupling ring, a coupling ring adjustment screw screw-coupled to the coupling ring adjustment nut, a connection pin coupling piece having a slot and extending from the inner circumferential surface toward the driving axis, and a connection pin inserting into the slot of the connection pin coupling piece to be capable of moving. The connection pin connects the connection pin coupling piece and a cylinder guide member formed on the outer circumferential surface of the cylinder.

A second speed-changing portion according to the first preferred embodiment comprises a sun gear fixed to the driving axis, a ring gear coupled to the driven plate of the first speed-changing portion to thereby rotate at varying speeds, and planetary pinion and planetary carrier for connecting the sun gear and the ring gear.

A second speed-changing portion according to the second preferred embodiment comprises a planetary gear portion for converting the speed of the driven plate of the first speed-changing portion, and a differential gear box for combining the rotational speed of the driving axis. Hereinafter, the present invention will be explained in detail with reference to the attached drawings.

Brief Description of the Drawings

FIG. 1 is a sectional view illustrating the cylinder of the first speed- changing portion, in a decelerating state, in the stepless transmission according to the present invention;

FIG. 2 is a sectional view illustrating the cylinder of the first speed- changing portion, in an accelerating state, in the stepless transmission according to the present invention;

FIG. 3 is a sectional view illustrating the supporting means of the driven plate and the second speed-changing portion according to the first preferred embodiment of the present invention; FIG. 4 is a sectional view illustrating the supporting means of the driven plate and the second speed-changing portion according to the second preferred embodiment of the present invention;

FIG. 5 is a partial sectional view illustrating the stepless transmission according to the first embodiment of the present invention;

FIG. 6 is a partial sectional view illustrating the stepless transmission according to the second preferred embodiment of the present invention;

FIG. 7 is a sectional view illustrating the stepless transmission according to the first embodiment in which the cylinder coupling ring and the cylinder are assembled;

FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7; FIG. 9 is a view for explaining the state in which the cylinder pivot axis connecting the cylinder and the cylinder casing and the leaf spring shown in FIG. 7 are assembled; FIG. 10 is a perspective view illustrating the double-sided cross gear;

FIGS. 11 and 12 are views for explaining the rotation of the cylinder shown in FIG. 7 when the driving plate and the driven plate are rotated;

FIG. 13 is a sectional view for explaining the state in which the cylinder and the cylinder coupling ring for adjusting the stepless speed- changing range in the stepless transmission according to the second preferred embodiment of the present invention are connected;

FIG. 14 is a sectional view illustrating the connection pin shown in FIG. 13 which is coupled to the connection pin coupling piece;

FIG. 15 is a sectional view illustrating the cylinder of the first speed- changing portion, in an accelerating state, in the stepless transmission according to the third preferred embodiment of the present invention;

FIG. 16 is a sectional view illustrating the cylinder of the first speed- changing portion, in a decelerating state, in the stepless transmission according to the third preferred embodiment of the present invention; FIG. 17 is a partial sectional view illustrating the stepless transmission according to the third preferred embodiment of the present invention;

FIG. 18 is a partial sectional view illustrating the cylinder of the first speed-changing portion, in a decelerating state, in the stepless transmission according to the fourth preferred embodiment of the present invention; and

FIG. 19 is a partial sectional view illustrating the cylinder of the first speed-changing portion, in an accelerating state, in the stepless transmission according to the fourth preferred embodiment of the present invention

Best mode for carrying out the Invention

FIGS. 1 and 2 show the cylinder 8 of the first speed-changing portion of the stepless transmission in a decelerating state and in an accelerating state, respectively, according to the first and second preferred embodiments of the present invention.

As shown in the drawing, when the rotational velocity of the driven plate 9 is low or decreasing, one of the rotating balls 7 in the cylinder 8 which contacts the driving plate 4 approaches the driving axis 1 along the arc-shaped surface of the inner surface of the driving plate 4. Contrarily, when the rotational velocity of the driven plate 9 is high or increasing, the rotating ball contacting the driving plate 4 is separated far from the driving axis 1 by the coupling ring adjusting means. The coupling ring adjusting means is operated by a manipulation of a user using a common controlling device. When the cylinder 8 is horizontally positioned by the coupling ring adjustment screw 12 (see FIGS. 5 and 6) operated by the controlling device, the cylinder 8 is disposed parallel to the driving axis 1. Thus, the rotational velocity of the driving plate 4 is transferred to the driven plate 9 at a ratio of about 1 :1. As a result, in FIGS. 1 and 2, the distance (Ra/2 and Ra72) between the left rotating ball contacting the driving plate 4 by the coupling ring adjusting means and the driving axis 1 and the distance (Rb/2 and Rb72) between the right rotating ball contacting the driven plate 9 and the driving axis 1 vary. Accordingly, it can be seen that the rotational velocity of the driven plate 9 is changed. Thus, according to the present invention, there is little loss in the output of an engine compared to the conventional automatic transmission using the frictional force of a fluid.

The output of an engine transmitted to the driving axis 1 is transmitted to the driving plate 4 rotating with the driving axis 1 and is further transmitted to the driven plate 9 via the rotating balls 7 contacting and pressing the inner surface of the driving plate 4. The radius (R₂/2) of each arc formed on the opposite surfaces of the driving plate 4 and the driven plate 9 equals the sum of the radii (R/2) of the rotating balls 7 in the cylinder 8.

The rotational speed v of the rotating balls 7 is V₄ (rotational velocity of the driven plate) x (Ra/R₁ or Ra'/R, ) and the rotational velocity V_g of the driven plate 9 is V₇ (rotational velocity of the rotating balls) x (R/Rb or R Rb'). Consequently, the rotational velocity of the driven plate 9 varies according to a change in the angle of disposition of the cylinder 8 with respect to the driving axis 1 as the cylinder 8 having the rotating balls 7 moves along the arc surface, and the value thereof can be calculated by V₄ x (Ra/Rb or RaVRb') which is expressed in Equation (1)

Vy - = V₄ x (RalR. or Ra'/R.)

-- V₇ (RJRb or RJRb¹) (1 )

= V₄ x (Ra/Rb or Ra'IRb')

FIG. 3 shows the supporting means of the driven plate 109 and the second speed-changing portion 120 according to the first preferred embodiment of the present invention. As shown in the drawing, the second speed-changing portion 120 includes a sun gear 123 fixed to the driving axis 1 , a ring gear 121 coupled to the driven plate 109 of the first speed-changing portion 110 and rotating at varying rotational velocities, and a planetary pinion 122 and a planetary carrier 124 for connecting the sun gear 123 and the ring gear 121.

The driven gear 109 transmits a rotational force received via the rotating balls 7 in the cylinder 8 to the ring gear 121 of the second speed- changing portion 120 connected to the driven plate 109. Then, the driven gear 109 combines the rotational velocity of the ring gear 121 with the rotational velocity of the sun gear 123 coupled to the driving axis 1 to rotate the planetary carrier 124 supporting the planetary pinion 122. The number of rotations of the planetary carrier 124, N_c, can be calculated by Equation (2). N_c = ( N_s Z_{s +} N_R Z_R) l( Z_{s +}Z_R) (2)

Here, N_s and Z_g are the number of rotations and the number of gears of the sun gear 123, respectively, and N_R and Z_R are the number of rotations and the number of gears of the ring gear, respectively.

FIG. 4 shows the supporting means of the driven plate 9 and the second speed-changing portion 120 according to the second preferred embodiment of the present invention. Referring to FIG. 4, the second speed-changing portion 120 of the second preferred embodiment includes a planetary gear portion 130 for changing the speed of the driven plate 9 of the first speed-changing portion and a differential gear box for combining the rotational velocity of the driving axis 1.

The rotational force of the driven plate 9 rotated by the rotational force received via the rotating balls 7 is transmitted to the planetary gear portion 130 and rotates a casing 20 having a differential gear and confining a speed converting gear axis 26 . Then, the driven plate 9 rotates the driven axis 24 having the driven gear 23 as the speed-changing gear 21 rotates by the difference between the number of rotations of the driving gear 22 coupled to the driving axis 1 and the number of rotations of the differential gear casing 20. Since the driven gear 23 rotates at a speed equivalent to a value determined by deducting the number of rotations of the driving gear 22 from twice the rotational velocity of the casing 20 (refer to Equation (3)), the driven gear 23 reversely rotates when the number of rotations of the driving gear 22 is twice the number of rotations of the casing 20. Thus, the driven axis 24 connected to the driven gear 23 can move a vehicle in a backward direction.

^₂₃ = 2 \ ₂₀- V ₂₂ (3)

FIG. 5 shows an assembled stepless transmission according to the first preferred embodiment of the present invention. As shown in the drawing, the coupling ring adjusting means includes a cylinder coupling ring 111 , a coupling ring adjustment nut 11 coupled to the outer circumference of the cylinder coupling ring 111 , a coupling ring adjustment screw 12 screw- coupled to the coupling ring adjustment nut 11 , an outside gear 200 coupled to the inner circumferential surface of the cylinder coupling ring 111 , and an inside gear 113 of a cylindrical shape having a geared portion formed on its outer circumferential surface, centered about the driving axis 1 by being supported by bearings 17 with respect to the outer circumferential surface of the driving axis 1 to face the outside gear 200. The outside gear 200 and the inside gear 113 are separated to face each other by a cylinder 8 interposed therebetween. The cylinder 8 has a cylinder rotation gear 312 and a circular gear 113a on its outer circumferential surface so as to be engaged with the outside gear 200 and the inside gear 113, respectively.

When the coupling ring adjustment screw 12 is rotated by a common controller manipulated by a driver, the cylinder coupling ring 111 moves forward and backward in the longitudinal direction of the driving axis 1 as indicated by arrow "b". Accordingly, the outside gear 200 formed on the inner circumferential surface of the cylinder coupling ring 111 pivots a double-sided cross gear 309 engaged with the outside gear 200 in a direction indicated by arrow "a" as the outside gear moves. Thus, the rotation ratio of the driivng plate 304 and the driven plate 109 are changed by changing the inclination of the cylinder 8. That is, the inside gear 113 supported by the bearings 17 and encompassing the driving axis 1 and the outside gear 200 provided on the inner circumferential surface of the cylinder coupling ring 111 are respectivley engaged with the double-sided cross gear 309 and the circular gear 113a provided on the upper and lower portions of the cylinder 8, respectively. Thus, when the cylinder coupling ring 111 is moved by the rotation of the coupling ring adjustment screw 12 in the directions indicated by "b", the double-side cross gear 309 and the circular gear 1 13a engaged with the outside gear 200 and the inside gear 113, respectivley, pivot in the directions indicated by arrow "a" so that the inclination of the cylinder 8 varies. Therefore, the speed of the driven plate 109 with respect to that of the driving plate 304 can be adjusted.

Also, as the driven plate 109 rotates, the ring gear 121 coupled to the driven plate 109 rotates and the sun gear 123 coupled to the driving axis 1 rotates according to the rotation of the driving axis. As mentioned above, the planetary pinion 122 is installed between the ring gear 121 and the sun gear 123 and the axis of the planetary pinion 122 is coupled to the planetary carrier 124 capable of rotating. The planetary carrier 124 is connected to the driven axis 24. Thus, by appropriately combining the speeds of the sun gear 123 and the ring gear 121 , varying rotational velocities of the driven axis 24 can be obtained.

FIG. 6 shows an assembled stepless transmission according to the second preferred embodiment of the present invention. The coupling ring adjusting means according to the second embodiment includes a cylinder coupling ring 5, a coupling ring adjustment nut 11 coupled to the outer circumference of the cylinder coupling ring 5, a coupling ring adjustment screw 12 scew-coupled to the coupling ring adjustment nut 11 , a connection pin coupling piece 25 having a slot and extending from the inner circumferential surface toward the driving axis 1 , and a connection pin 6 inserting in the slot of the connection pin coupling piece 25 to be capable of moving. The connection pin 6 connects the connection pin coupling piece

25 and a cylinder guide member 37 formed on the outer circumferential surface of the cylinder 8 and moves in the connection pin coupling piece 25.

When the coupling ring adjustment screw 12 is rotated by a common controller manipulated by a vehicle operator, the cylinder coupling ring 5 moves forward and backward in the longitudinal direction of the diriving axis 1. Accordingly, as the connection pin 6 being inserted into the slot of the connection pin coupling piece 25 extending toward the driving axis 1 moves in the longitudinal direction of the connection pin coupling piece 25, the ratio of the rotational velocities between the driving plate 4 and the driven plate 9 varies by changing the angle of disposition of cylinder 8. Since the cylinder 8 pivots in the directions indicated by arrows "c" as the cylinder coupling ring 5 moves forward or backward, the contact position of the rotating balls 7 with respect to the arc inner surfaces of the driving plate 4 and the driven plate 9 changes, thereby changing the speed.

A planetary carrier fixing means 14 is for fixing the planetary carrier 13. Thus, when a vehicle operator operates an accelerator of a vehicle or a braking means, the planetary carrier fixing means 14 fixes the planetary carrier 13 by a well-known controller so that the planetary pinion 15 rotates to transmit a rotational force received from the driven plate 9 to a ring gear 19. When the vehicle operator wants to stop the vehicle temporarily without completely stopping the engine of the vehicle, i.e., in an idle state, the planetary carrier 13 rotates in a state in which the planetary carrier fixing means 14 is maintained being separated by a predetermined distance from the planetary carrier 13. Accordingly, the planetary pinion 15 rotate idly so that the rotational force of the driven plate 9 is not transmitted to the ring gear 19. Thus, there is no rotational force transmitted to the driven axis 24 5 of the second speed-changing portion 120.

In the first and second preferred embodiments of the present invention, it is preferable that there are between 3-6 cylinders 8 and between 2-7 rotating balls 7 in each cylinder 8. The number of the rotating balls 7 becomes even- or odd-numbered to secure a smooth speed-chaning o manipulation according to the shape of the driving plates 4 and 304 and the driven plates 9 and 109. Although the rotating balls 7 in the cylinder 8 are linearly arranged in the drawings, the present invention is not limited to the embodiments shown in the drawings. When the number of rotating balls 7 is odd-numbered, the rotational direction of the driven plates 9 and 109 is 5 opposite to that of the driving plates 4 and 304.

FIGS. 7 through 12 show the first speed-changing portion according to the first preferred embodiment of the present invention.

As shown in FIG. 7, in the first speed-changing portion 110 of the present embodiment, the inside gear 113 is supported by the bearings 17 0 capable of moving freely on the outer circumferential surface of the driving axis 1 and the gear formed on the outer circumferential surface of the inside gear 113 is engaged with the circular gear 113a provided on the outer circumferential surface of a cylinder casing 314. The geared portion of the circular gear 113a is a rounded surface having a bulged center portion. In the circular gear 113a shown in FIG. 7, the center point of the partially arc shaped gear 113a positioned at the center point of the cylinder 8. Thus, although the cylinder 8 and the cylinder casing 314 rotate in directions indicated by arrows "d", the gear engagement between the inside gear 113 and the circular gear 113a is stably maintained.

Also, a cylinder rotation gear 312 having teeth in a direction perpendicular to the teeth of the circular gear 113a is installed on the outer circumferential surface of the cylinder casing 314 disposed opposite the circular gear 113a with respect to the cylinder 8. The surface of the cylinder rotation gear 312 is a partial arc shape corresponding to a circle centered about the cylinder 8. The cylinder rotation gear 312 is engaged with the double-sided cross gear 309 and a slip prevention pin 310 for preventing the engaged gears from slipping is interposed between the cylinder rotation gear 312 and the double-sided cross gear 309.

The double-sided cross gear 309 is a gear having geared portions formed on the respective upper and lower surfaces of a rectangular planar member in which the directions of the upper gear teeth and the lower gear teeth are perpendicular to each other. Also, the lower geared surface of the double-sided cross gear 309 engaged with the cylinder rotation gear 312 is a partial arc shape centered about the driving axis 1. The upper geared surface is a round shape of a partial arc of an imaginary circle having a center at the center of the cylinder 8 like the above-described circular gear 1 13a.

A cylinder rotation prevention member 311 is provided on the inner circumferential surface of the cylinder coupling ring 111. The cylinder rotation prevention member 311 has an end portion extending toward the center of the cylinder coupling ring 111 to a predetermined length to prevent rotation of the cylinder casing 314 over a predetermined range. Also, reference numeral 315 indicates a cylinder pivot axis. A leaf spring 313 provides an elastic force so that the cylinder casing 413 can be elastically coupled to the cylinder 8.

FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7. In the drawing, the upper surface of the double-sided cross gear 309 is engaged with the outside gear 200 and simultaneously the lower surface thereof is engaged with the cylinder rotation gear 312. Also, a slip prevention pin 310 is interposed between the cylinder rotation gear 312 and the double-sided cross gear 309.

FIG. 9 shows the cylinder pivot axis 315 and the leaf spring 313 coupled to the cylinder 8. FIG. 10 shows the double-sided gear 309 in which the upper surface and the lower surface thereof are engaged with the outside gear 200 and the cylinder rotation gear 312, respectively.

FIG. 11 shows a state in which the center line "u" of the cylinder pivot axis315 forms a caster angle "θ" with respect to a tangent line "v" at the tangent point at which the driving plate 304 or the driven plate 109 contacts the rotating balls 7 while the driving plate 304 and the driven plate 109 rotate in a direction indicated by arrow "e" to transmit a rotational force.

As shown in the drawing, when the driving plate 304 and the driven plate 109 rotate in a direction indicated by arrow "e", the rotating balls 7 being in a frictional contact with the plates receive pressure to rotate the cylinder 8 in a direction indicated by arrow "f" until stopped by the rotation prevention member 311. Thus, the angle "θ" is formed with respect to a tangent line "v" at the tangent point at which the driving plate 304 or the driven plate 109 contacts the rotating balls 7 so that the leaf spring 313 confining the cylinder 8 shares the rotational force applied to the respective rotating balls 7. That is, most of the rotational force generated by the driving plate 304 is transmitted to the driven plate 109 through the rotating balls 7 and a part thereof is used as a force for maintaining the cylinder 8 by rotating the same by the angle "θ" in the direction "f . Here, the rotating ball in the cylinder 8 rotating in contact with the driving plate 304 or the driven plate 109 located away from the driving axis 1 receives more pressure than the rotating ball in the cylinder 8 rotating in contact with the driving plate 304 or the driven plate 109 located closer to the driving axis 1 due to a difference in the angular velocity Accordingly, as the cylinder 8 rotates by the operation of the caster of the cylinder pivot axis 315, the rotating ball is pulled toward the driving axis 1 so that the distances Ra, Ra', Rb and Rb' between the other opposite rotating balls (see FIGS 1 and 2) becomes equal and the leaf spring 313 confining the cylinder 8 receives a greater pressure Contranly, since the rotating ball having shorter distances Ra, Ra', Rb and Rb' than the other rotating balls receives less pressure, the load of the rotational force to the leaf spring 313 decreases Then, as the cylinder 8 rotates due to the above operation of the caster, the rotating ball is pushed away from the driving axis 1 and thus the distances Ra, Ra', Rb and Rb' between the other opposite rotating balls (see FIGS 1 and 2) becomes equal

FIG 12 shows a state in which the center line "u" of the cylinder pivot axis 315 forms a caster angle "θ" with respect to a tangent line "v" at the tangent point at which the driving plate 304 or the driven plate 109 contacts the rotating balls 7 while the driving plate 304 and the driven plate 109 rotate in a direction indicated by arrow "g" The operational principle is the same as the above descriptions with reference to FIG 11 FIG 13 shows the cylinder 8 and the cylinder coupling ring 5 according to the second preferred embodiment of the present invention, and FIG 14 shows the connection pin 6 inserted in the slot formed in the connection pin coupling piece 25 The same reference numerals indicate elements having the same functions FIGS 15 and 16 show a third preferred embodiment of the present invention, in which FIG 15 is for showing the position of the cylinder 8 in a high speed or accelerating state and FIG 15 is for showing the position of the cylinder 8 in a low speed or decelerating state

As shown in the drawings, in the stepless transmission according to the present embodiment, the driving plate 27 has a bulged portion different from the shapes of the first and second preferred embodiments In this embodiment, the number of rotating balls 7 in the cylinder 8 is two FIG. 17 shows an assembled state of the stepless transmission according to the third preferred embodiment of the present invention. Here, the same reference numerals indicate the elements having the same functions. As shown in the drawing, in the planetary gear 130 interacting with the first speed-changing portion 110, the ring gear fixing device 34 fixes the ring gear 19 and the planetary carrier 13 and the casing 20 of the second speed- changing portion 120 are fixed by a combining means 36 such as bolts, different from FIG. 4. The structure and operation of the second speed- changing portion 120 is the same as those of the second speed-changing portion of FIGS. 4 or 6. Here, the arrangement of the planetary gear 130 and the second speed-changing portion 120 can be positioned reversely, and In this case, the rotation direction of the driven plate 24 is reversed accordingly. Also, the rotational velocity can be changed by adjusting the combination of the number of gears of the planetary gear 130.

In the present embodiment shown in FIG. 17, the coupling ring adjusting means, different from the structure shown in FIG. 6, includes a cylinder adjustment rod 30 connected to the cylinder 8, an adjustment rod guide ring 29 for guiding the cylinder adjustment rod 30, an adjustment rod ring gear 31 engaged with a gear formed on the cylinder adjustment rod 30, an adjustment ring gear fixing device 32 for fixing the adjustment rod ring gear 31 , and an adjustment gear 33 engaged with said adjustment rod ring gear 31. As in the above embodiments, when the adjustment rod ring gear 31 moves the cylinder adjustment rod 30 by a well-known controller by manipulation of an operator, the cylinder 8 moves in a space between a driving plate 27 and a driven plate 28 so that the rotational velocity of the driving plate 27 is transmitted to the driven plate 28.

FIGS. 18 and 19 show a fourth preferred embodiment of the present invention, in which FIG. 18 is for showing the position of the cylinder 8 in a high speed or accelerating state and FIG. 19 is for showing the position of the cylinder 8 in a low speed or decelerating state.

As shown in the drawings, in the present embodiment, a driving plate 47 has a cone shape and a driven plate 48 has an inner circumferential surface formed to be parallel to the outer circumferential surface of the driving plate 47 so that the cylinder 8 moves perpendicular to both the outer circumferential surface of the driving plate 47 and the inner circumferential surface of the driven plate 48. Also, the number of rotating balls 7 in the cylinder 8 is two or even-numbered. It is preferable that there are 3-6 cylinders 8.

The structures and operations of the planetary gear 130 and the second speed-changing portion 120 in the present embodiment are the same as those of the third embodiment. Also, the above Equations (1) through (3) can be applied to the present embodiment.

Industrial Applicability

As described above, according to the present invention, a speed change is possible without disengaging the engine and the transmission. Also, the structure of the transmission is simplified, the transmission is light, and there is little loss in the engine output.

Claims

What is claimed is: ι 1. A stepless transmission comprising:

2 a driving axis (1) receiving a rotational force from an engine, a motor

3 or a rotating apparatus; a first speed-changing portion (110) for primarily changing a rotational

5 velocity transferred from said driving axis (1); and

6 a second speed-changing portion (120) for providing a driving power

7 of various rotation ratios to a driven axis (24) by combining the rotational

8 velocity transferred from said first speed-changing portion (110) with the

9 rotational velocity transferred from the driving axis (1).

ι 2. The stepless transmission of claim 1 , wherein said first speed-

2 changing portion (110) comprises:

3 a driving plate having a ring-type groove of which the profile is arc-

4 shaped formed on the inner surface of the driving plate around said driving

5 axis (1) and spline-coupled to a driving plate confining groove (10) formed

6 on said driving axis (1);

7 a driven plate having the same groove as that of said driving plate

8 and disposed to face the inner surface of said driving plate;

9 a cylinder (8) installed between said driving plate and said driven ιo plate; ιι rotating balls (7) assembled together inside said cylinder (8) to not be

12 separated and rotate with friction and roll on the surface of the groove

13 formed on the inner surfaces of said driving plate and said driven plate;

1 a coupling ring adjusting means for changing the speed of rotation of

15 said driving axis (1) by controlling the angle of disposition of said cylinder (8)

16 with respect to said driving axis (1);

17 elastic supporting means (3) and (103), installed between said driving is plate and first fixed plates (2) and (102) which are fixed to said driving axis

19 (1) between said engine and said the driving plate, for elastically supporting

20 said driving plate; and

21 second fixed plates (18) and (118) installed to the rear of bearings 2 (17) which are interposed between said driving axis (17) and said driven 3 plate.

ι 3. The stepless transmission of claim 2, wherein said coupling

2 ring adjusting means comprises:

3 a cylinder coupling ring (111);

4 an outside gear (200) provided on the inner circumferential surface of

5 said cylinder coupling ring (111);

6 a double-sided cross gear (309) having one side surface engaged

7 with said outside gear (200);

8 a cylinder rotation gear (312) engaged with the other side surface of

9 said double-sided cross gear (309); ιo a slip prevention pin interposed between said cylinder rotation gear ιι (312) and said double-sided cross gear (309);

12 an inside gear (113) of a cylindrical shape having a geared portion

13 opposite said outside gear (200) and encompassing a portion of said driving

14 axis (1) and simultaneously being supported by bearings (17) on the outer is circumferential surface of said driving axis; and

16 a circular gear (113a) installed on the outer circumferential surface of

17 said cylinder (8) and engaged with said inside gear (113).

1 4. The stepless transmission of claim 3, wherein said circular gear

2 (113a) engaged with said inside gear (113) has a partial arc profile and said

3 double-sided cross gear (309) of a rectangular plane has a geared portion

4 on each of both sides in directions perpendicular to each other, the profile

5 of the upper surface gear portion of said double-sided cross gear (309) is an

6 approximate partial arc and that of the lower surface gear portion thereof is

7 a partial arc perpendicular to the direction of the upper surface of said gear

8 portion.

ι 5. The stepless transmission of claim 3, further comprising:

2 a cylinder casing (314) for confining the rotation of said cylinder (8); 3 a cylinder pivot axis (315) installed on the side portion of said cylinder

4 casing (314); and

5 a leaf spring (313) installed on the outer circumferential surface of

6 said cylinder (8) for controlling the rotation of said cylinder (8) by the

7 operation of a caster of said cylinder pivot axis (315), when the distances

8 from said driving axis to the contact points between said rotating balls and

9 said driving plate (304) and said driven plate (109) which are rotating, are ιo not coincident, ιι wherein said cylinder pivot axis (315) as said cylinder (8) rotates

12 forms a caster angle of a predetermined number of degrees with respect to

13 the tangent at the contact point between said rotating balls (7) and said

14 driving plate (304) or said driven plate (109).

1 6. The stepless transmission of claim 3, further comprising a

2 cylinder rotation prevention member (311) for allowing said cylinder pivot

3 axis (315) to form a caster angle with respect to the tangent at the contact

4 point between said rotating balls (7) and said driving plate (304) or said

5 driven plate (109) by controlling the rotation of said cylinder (8) due to

6 pressure generated to said rotating balls (7) rotating respectively in contact

7 with the inner surfaces of said driving plate (304) and said driven plate (109)

8 at a predetermined position on the inner circumferential surface of said

9 cylinder coupling ring (111).

ι 7. The stepless transmission of claim 2, wherein said coupling

2 adjusting means comprises:

3 a cylinder coupling ring (5);

4 a coupling ring adjustment nut (1 ) provided on the outer

5 circumferential surface thereof;

6 a coupling ring adjustment screw (12) screw-coupled to said coupling

7 ring adjustment nut (11);

8 a connection pin coupling piece (25) extending toward the center of

9 said cylinder coupling ring (5) and having a slot formed thereon; and 10 a connection pin (6) inserted in the slot of said connection pin ιι coupling piece (25),

12 wherein said connection pin (6) connects the connection pin coupling

13 piece (25) and a cylinder guide member (37) provided on the outer

14 circumferential surface of said cylinder (8) and simultaneously moves up and is down in the slot so that the angle of disposition of said cylinder (8) with 16 respect to said driving axis (4) is changed.

ι 8. The stepless transmission of claim 2, wherein said coupling

2 ring adjusting means comprises:

3 a cylinder adjustment rod (30) one end thereof connected to the outer

₄ circumferential surface of said cylinder (8) and having a shape of a partial

5 arc of a predetermined width, a geared portion being formed on the outer

6 side of said partial arc;

7 an adjustment rod guide ring (29) for guiding said cylinder adjustment

8 rod (30);

9 an adjustment rod ring gear (31) engaged with a gear formed on said ιo cylinder adjustment rod (30); ιι an adjustment ring gear fixing device (32) for fixing the adjustment rod

12 ring gear (31); and

13 an adjustment gear (33) engaged with said adjustment rod ring gear

14 (31 ).

ι 9. The stepless transmission of claim 1 , wherein said second

2 speed-changing portion (120) is connected to ring gears (19) and (121) via

3 a planetary pinion (15) and sun gears (16) and (123) coupled to said driving

4 axis (1) are coupled to said planetary pinion (15).

ι 10. The stepless transmission of claim 1 , wherein said second

2 speed-changing portion (120) adjusts the rotational velocity of said casing

3 (20) confining a speed converting gear axis (26) relatively to the rotational

4 velocity of said driving gear (22) so that the rotational velocity of a driven 5 gear (23) equals the a value obtained by deducting the velocity of said

6 driving gear (22) from twice the the rotational velocity of said casing (20).

ι 11. The stepless transmission of claim 2, wherein the profiles of the

2 inner surfaces of driving plates (4) and (304) and said driven plates (9) and

3 (109) facing each other is concave.

ι 12. The stepless transmission of claim 2, wherein the profile of the

2 inner surface of a driving plate (27) is convex and the profile of the inner

3 surface of said driven plate (27) is concave.

ι 13. The stepless transmission of claim 2, wherein the outer

2 circumferential surface of a driving plate (47) has a cone shape and a driven

3 plate (48) has the inner circumferential surface formed to be parallel to the

4 outer circumferential surface of said driving plate (47) so that said cylinder

5 (8) moves substantially perpendicular to both the outer circumferential

6 surface of said driving plate (47) and the inner circumferential surface of said

7 driven plate (48).

ι 14. The stepless transmission of claim 2, wherein the radius of the

2 arc surface of said driving plates (4) and (304) or said driven plates (9) and

3 (109) equals to the sum of the radii of the respective rotating balls (7).

ι 15 The stepless transmission of claim 2, wherein an indentation

2 is formed on the outer surface of said driving plate (304) and a supporting

3 plate (301) is installed in said indentation so that oil can be injected in a

4 chamber (306) formed in a spacing between said indentation and said

5 supporting plate (301), and said supporting plate (301) is urged by said leaf

6 spring (103) installed at said fixed plate (102).