CAM-CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION SYSTEMS
20230313866 · 2023-10-05
Inventors
Cpc classification
B62M9/16
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
An arrangement for balancing axial forces in driver and driven clutches of a continuously variable transmission system that may include but is not limited to a pulley, a sheave mechanism, a driver clutch mechanism, or driver clutch, a driven pulley mechanism, a driven clutch mechanism, or driven clutch, and a shifting mechanism, servo, actuator mechanism, or actuator. The torque transmitted by the continuously variable transmission system is converted to axial forces acting upon belt. The forces in driver and driven clutches are balanced to minimize the force required for speed changes by shifting mechanism.
Claims
1. A cam-controlled continuously variable transmission system comprising: a driver clutch, wherein the driver clutch comprises: a driver shaft; a first driver sheave fixed to the driver shaft; a second driver sheave moveable parallel to an axis of rotation of the driver shaft; the first driver sheave locked in a rotating relation with the first driver sheave by a member cooperatively engaged with a second driver sheave receiving member, the driver sleeve having at least one driver slot disposed at a driver slot angle with respect to the axis of rotation of the driver shaft; a driven clutch connected by a belt to said driver clutch, wherein the belt trained around the driver clutch and the driven clutch positioned between the first driver sheave, the second driver movable sheave, the first driven sheave, and the second driven movable sheave, wherein the driven clutch comprises: a driven shaft; a first driven sheave fixed to the driven shaft; a second driven sheave moveable parallel to an axis of rotation of the driven shaft; the second driven sheave locked in rotating relation with the first driven sheave by a member cooperatively engaged with a second driven sheave receiving member, the driven sleeve having at least one driven slot disposed at a driven slot angle with respect to the axis of rotation; an actuator engaged with a carrier, wherein the carrier is rotatably journaled with a bearing, wherein the bearing is rotatably journaled with the second driver sheave for axially displacing the second driver sheave, wherein the contact radii between belt and first and second driven and driver sheaves in the are changed in response to input from the actuator causing driven clutch speed up or slow down versus driver clutch in a controlled manner; at least one driver pin contacting the side of at least one driver slot optimizing force transmission from the belt; and at least one driven pin contacting the side of at least one driven slot optimizing force transmission from the belt.
2. The cam-controlled continuously variable transmission system of claim 1, wherein the carrier is a driver carrier.
3. The cam-controlled continuously variable transmission system of claim 1, wherein the carrier is a driven carrier.
4. The cam-controlled continuously variable transmission system of claim 1, wherein the bearing is a thrust bearing.
5. The cam-controlled continuously variable transmission system of claim 1, wherein the driver slot angle and the driven slot angle are constant.
6. The cam-controlled continuously variable transmission system of claim 1, wherein the driver slot angle and the driven slot angle have a variable angle.
7. The cam-controlled continuously variable transmission system of claim 5, wherein the starting angle in the driver clutch is approximately 16 degrees at a first end of at least one driver slot and gradually increases to an angle in the range of 38 degrees at a second end of the at least one driver slot, and the starting slot angle in the at least one driven slot is in the range of generally 60 degrees at a first end and gradually decreases to an angle in the range of 35 degrees at a second end of the at least one driven slot.
8. The cam-controlled continuously variable transmission system of claim 1, wherein the first portion of the at least one driver slot is parallel to axis of rotation.
9. The cam-controlled continuously variable transmission system of claim 1, wherein the actuator is engaged with the carrier by a link rotatably journaled with the carrier.
10. The cam-controlled continuously variable transmission system of claim 1, wherein the actuator is engaged with the carrier by an eccenter, wherein said eccenter is rigidly attached to an output shaft of the actuator and cooperatively engaged with the carrier.
11. The cam-controlled continuously variable transmission system of claim 1, wherein the actuator comprises a screw for force multiplication.
12. The cam-controlled continuously variable transmission system of claim 1, wherein the actuator actuates the second driver sheave.
13. The cam-controlled continuously variable transmission system of claim 1, wherein the actuator is configured to move the second driven sheave axially along the driven shaft.
14. The cam-controlled continuously variable transmission system of claim 1, wherein the force applied by the actuator generally coincides with the area of contact between the belt and the second driver sheave and the second driven sheave, thereby countering the force of the belt acting on the second driver sheave and the second driven sheave.
15. The cam-controlled continuously variable transmission system of claim 1, wherein more than one pin is cooperatively engaged with at least one driver slot and at least one driven slot.
16. The cam-controlled continuously variable transmission system of claim 1, wherein the position of the at least one driver slot and at least one driven slot are shifted axially in relation to each other.
17. The cam-controlled continuously variable transmission system of claim 1, wherein the at least one driver slot and at least one driven slot have sides not parallel to each.
18. The cam-controlled continuously variable transmission system of claim 1, wherein at least one side of at least one driver slot and at least one driven slot is open.
19. The cam-controlled continuously variable transmission system of claim 1, wherein the driver shaft is connected to a bicycle crank.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Non-limiting and non-exhaustive embodiments of the disclosed technology are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
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[0031] It should be understood that the drawings are not necessarily to scale, and various dimensions may be altered. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.
TABLE-US-00001 A1—angle FR2—force radial S51—side of slot A2—angle FX2—force axial S52—side of slot SA—angle TFX1—total axial force S53—side of slot SA1—angle TFX2—total axial force 2—shaft SA2—angle BF—belt force 4—driver sleeve AX—axis of rotation BFX1—belt axial force 8—fixed sheave AX1—axis BFX2—belt axial force 10—movable sheave AX2—axis R—cam radius 12—pin D1—direction of rotation S1—slot 12X—axis D3—direction S2—slot 14—bearing FN1—force normal S3—slot 16—carrier FR1—force radial S4—slot 16B—carrier FX1—force axial S3B—slot start 16C—cavity FN2—force normal S5—slot 18—retaining ring 20—bushing/bearing 34—sheave fixed 42—actuator arm 22—retaining ring 36—shaft output 43—shaft 24—O-Ring/sealing ring 36B—flange 44—link 30—speed sensor 38—spring 46—housing 32—sheave movable 39—driven sleeve 48—bolt 33—pin S39—slot 50—belt 33X—axis 40—actuator 52—eccenter
DETAILED DESCRIPTION
[0032] As indicated above, the present description provides relates to continuously variable transmission controlled through the use of a cam system for balancing axial forces in driver and driven clutches and systems and methods of making the same. The present application More specifically the present application relates to CVT cam-controlled systems for automotive, industrial, and personal mobility, such as bicycles, and the like applications.
[0033] In the following description, reference is made to the accompanying drawing that forms a part hereof and in which is shown by way of illustration at least one specific implementation. The following description provides additional specific implementations. These embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that other implementations are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense. While the present disclosure is not so limited, an appreciation of various aspects of the disclosure will be gained through a discussion of the examples, including the figures, provided below. In some instances, a reference numeral may have an associated sub-label consisting of a lower-case letter to denote one of multiple similar components. When reference is made to a reference numeral without specification of a sub-label, the reference is intended to refer to all such multiple similar components.
[0034] As shown in
[0035] In some embodiments, the driver clutch 100 may be connected with driven clutch 200 via a belt 50. The belt 50 may be of the type of an endless belt, a segmented belt, or the like. The belt 50 may transmit power from the driver clutch to the driven clutch. Speed sensors 30 are fixedly attached to the housing 46 (attachment not shown) to monitor the rotational speed of the driven and driver clutches.
[0036] In some embodiments, as shown if
[0037] Sealing rings 24, such as but not limited to O-rings, sit in grooves formed on the inside diameter of driver sleeve 4 positioned close to each end of driver sleeve 4. The sealing rings prevent grease (not shown) that may fills slots S4 from purging outside which may cause accelerated wear of the system.
[0038] A movable second driver sheave 10 is fixedly attached to driver sleeve 4 so it moves in unison with driver sleeve 4. Inside diameter of a thrust bearing 14 is fixedly attached to an outside diameter of a stem of movable second driver sheave 10. A retaining ring 18 prevents bearing 14 from sliding out of movable second driver sheave 10. A carrier 16 is fixedly attached to the outside diameter of bearing 14. In one embodiment, bearing 14 may be a ball bearing type bearing, but may also be a roller or needle type bearing. In yet other embodiments bearing 14 may be a coated busing configured to act as a ball bearing would.
[0039] Driver shaft 2, the fixed first driver sheave 8, movable second driver sheave 10, driver sleeve 4, and pins 12 may be made of steel alloys, however, in some embodiments, these components may be manufactured from other metals such as aluminum alloys titanium alloys; polymers such as but not limited to ABS or HDPE; or composite materials, such as but not limited to carbon fiber reinforced composites. In some embodiments, two pins 12 spaced approximately 180 degrees apart may be beneficial. In other embodiments, more pins and corresponding slots may be used to transmit high torque in applications where this is needed.
[0040] As shown in
[0041] As shown if
[0042] In some embodiments, a compression spring 38 is slidingly journaled over the stem of the movable sheave 32. One end of spring 38 pushes sheave 32 towards fixed first driven sheave 32 while the other end of spring 38 rests against flange 36B formed at the end of shaft 36. Shaft 36, fixed first driven sheave 34, movable second driven sheave 32, driven sleeve 39, and pins 33 may be made of steel alloys, however, in some embodiments, these components may be manufactured from other metals such as but not limited to aluminum alloys titanium alloys; polymers such as but not limited to ABS or HDPE; or composite materials, such as but not limited to carbon fiber reinforced composites. In some embodiments, the CVT Cam system may include three pins 33 spaced 120 degrees apart. In other embodiments, more pins may be used to transmit higher torque.
[0043] As shown in
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[0045] As shown in
[0046] As shown in
[0047] The sum of all axial forces FX1 is designated TFX1 and is shown in
TFX1=2×FX1
[0048] AS shown in
ΣFX2=TFX2
TFX2+SF=BFX2
[0049] The amount of force SF is small compared to the axial forces TFX2. In one embodiment the spring force SF may fluctuate between 1/20 to 1/10 of the force TFX2. In some embodiments, the function of spring 38 may be to assure maintained contact between the belt 50 and second driven sheave 32 and a the first driven sheave 34 before torque is applied to shaft 2 to enable the CVT system of the present invention to start transmitting torque without belt slip. Once torque is applied, axial forces generated on surface of slot S4 and on surface of slot S39 may be optimally proportional to torque and therefore adequate to transmit torque via belt 50 without belt slip. In one embodiment the spring 38 may be a coil-type spring, a torsion-type spring, a wave spring, or the like. In some embodiments of the cam-controlled continuously variable transmission system, the force applied by the actuator may generally coincide with the area of contact between the belt and the second driver sheave and the second driven sheave, thereby countering the force of the belt acting on the second driver sheave and the second driven sheave.
[0050] The contact radii between the belt and the sheaves in the driver and driven clutch changes in response to input from the actuator mechanism 300 causing the driven clutch to speed up or slow down in comparison to the driver clutch altering the speed ratio. Change of the contact radius between the belt and the sheaves is realized by moving the second driver sheave 10 along axis of rotation AX1. As shown in
[0051] As shown in
[0052] In some embodiments angle A2 is such that the sum of forces FX2 generated on surface of slots S39 by all pins 33 generally balance axial belt force BFX2.
[0053] In some embodiments of the cam-controlled continuously variable transmission system it may be beneficial for the driver slot angle and the driven slot angle to be constant. In others it may be beneficial for the driver slot angle and the driven slot angle to have a variable angle. In some embodiments the may be accomplished by having a starting angle in the driver clutch that is approximately 16 degrees at a first end of at least one driver slot and gradually increases to an angle in the range of 38 degrees at a second end of the at least one driver slot, and the starting slot angle in the at least one driven slot is in the range of generally 60 degrees at a first end and gradually decreases to an angle in the range of 35 degrees at a second end of the at least one driven slot.
[0054] In the majority of applications, the magnitude of axial force acting on the belt may depend on the radius at which the belt contacts the sheaves. If too much force is applied, it may result in undue stress on the CVT system and premature belt wear. If too little force is applied, it may result in belt slip followed by belt failure.
[0055] In some embodiments, the angles of slots in driver clutch and slots in driven clutch are calculated to balance belt forces so as to result in optimum belt compression and stable operation of the CVT system. In one embodiment, the slot angle SA3 in the preliminary stage (driver clutch side) is approximpentlyl 6 degrees and slot angle SA2 is approximately 33 degrees. Slots in the driven clutch may have angle SA3 of approximately 60 degrees and slot angle SA2 of approximately 30 degrees. In some embodiments, the approximate angle range may be in the range of plus or minus 5 degrees from the stated value depending on the parameters to be optimized.
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[0057] In yet another embodiment shown in
[0058] As shown in
[0059] In yet another embodiment shown in
[0060] In some embodiments a cam-controlled continuously variable transmission system may include but is not limited to a driver clutch, a driven clutch connected by a belt to said driver clutch, wherein the belt trained around the driver clutch and the driven clutch positioned between the first driver sheave, the second driver movable sheave, the first driven sheave, and the second driven movable sheave; an actuator engaged with a carrier, wherein the carrier is rotatably journaled with a bearing, wherein the bearing is rotatably journaled with the second driver sheave for axially displacing the second driver sheave, wherein the contact radii between belt and first and second driven and driver sheaves in the are changed in response to input from the actuator causing driven clutch speed up or slow down versus driver clutch in a controlled manner; at least one driver pin contacting the side of at least one driver slot optimizing force transmission from the belt; and at least one driven pin contacting the side of at least one driven slot optimizing force transmission from the belt. In some embodiments the driver clutch may include but is not limited to a driver shaft; a first driver sheave fixed to the driver shaft; a second driver sheave moveable parallel to an axis of rotation of the driver shaft; and the first driver sheave locked in a rotating relation with the first driver sheave by a member cooperatively engaged with a second driver sheave receiving member, the driver sleeve having at least one driver slot disposed at a driver slot angle with respect to the axis of rotation of the driver shaft. In some embodiments the driven clutch may include but is not limited to a driven shaft; a first driven sheave fixed to the shaft; a second driven sheave moveable parallel to an axis of rotation of the driven shaft; and the second driven sheave locked in rotating relation with the first driven sheave by a member cooperatively engaged with a second driven sheave receiving member, the driven sleeve having at least one driven slot disposed at a driven slot angle with respect to the axis of rotation.
[0061] From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the scope of the invention. Features or elements from one embodiment may be used or exchanged with features or elements of another embodiment. Accordingly, the invention is not limited except as by the appended claims.
[0062] Although the technology has been described in language that is specific to certain structures and materials, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific structures and materials described. Rather, the specific aspects are described as forms of implementing the claimed invention. Because many embodiments of the invention can be practiced without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.
[0063] Unless otherwise indicated, all number or expressions, such as those expressing dimensions, physical characteristics, etc., used in the specification (other than the claims) are understood as modified in all instances by the term “approximately” or “about.” At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the claims, each numerical parameter recited in the specification or claims which is modified by the term “approximately” or “about” should at least be construed in light of the number of recited significant digits and by applying rounding techniques. Moreover, all ranges disclosed herein are to be understood to encompass and provide support for claims that recite any and all sub-ranges or any and all individual values subsumed therein. For example, a stated range of 1 to 10 should be considered to include and provide support for claims that recite any and all sub-ranges or individual values that are between and/or inclusive of the minimum value of 1 and the maximum value of 10; that is, all sub-ranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less (e.g., 5.5 to 10, 2.34 to 3.56, and so forth) or any values from 1 to 10 (e.g., 3, 5.8, 9.9994, and so forth).