GB2449916A - Variable ratio belt drives - Google Patents

Variable ratio belt drives Download PDF

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Publication number
GB2449916A
GB2449916A GB0711030A GB0711030A GB2449916A GB 2449916 A GB2449916 A GB 2449916A GB 0711030 A GB0711030 A GB 0711030A GB 0711030 A GB0711030 A GB 0711030A GB 2449916 A GB2449916 A GB 2449916A
Authority
GB
United Kingdom
Prior art keywords
pulley
belt
drive
compound
diameter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB0711030A
Other versions
GB0711030D0 (en
Inventor
Brian Jay Hollatz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AGCO do Brasil Comercio e Industria Ltda
Original Assignee
AGCO do Brasil Comercio e Industria Ltda
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by AGCO do Brasil Comercio e Industria Ltda filed Critical AGCO do Brasil Comercio e Industria Ltda
Priority to GB0711030A priority Critical patent/GB2449916A/en
Publication of GB0711030D0 publication Critical patent/GB0711030D0/en
Publication of GB2449916A publication Critical patent/GB2449916A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H9/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members
    • F16H9/02—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion
    • F16H9/04—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes
    • F16H9/12—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members
    • F16H9/14—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members using only one pulley built-up out of adjustable conical parts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H9/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members
    • F16H9/02—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion
    • F16H9/04—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes
    • F16H9/12—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H9/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members
    • F16H9/02—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion
    • F16H9/04—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes
    • F16H9/12—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members
    • F16H9/16—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members using two pulleys, both built-up out of adjustable conical parts

Abstract

A variable ration belt drive, e.g. for a combine harvester, comprises a first belt 11, a compound double pulley 13 having a first variable diameter pulley 14 engaged by the first belt 11 and a second variable diameter pulley 15 engaged by a second drive belt 16.The compound double pulley 15 is arranged such that increases in an effective diameter of one pulley produces corresponding reductions in effective diameter of the other pulley. The belt drive further comprises a third spring-loaded variable diameter pulley 17 which also engages the second drive belt 16, and a control actuator 24 for varying the effective diameters of the first and second drive pulleys 14, 15 thus varying an overall ratio of the belt drive.

Description

Belt Drives Present invention relates to belt drives and rn particular,
though not exclusively, to belt drives for use in combine harvesters to drive such devices as cleaning/separating fans It is an object of the present invention to provide an improved form of belt drive which provides a high overall drive ratio range and in which the operative drive ratio can easily be varied.
Thus, according to the present invention, there is provided a variable ratio belt drive comprising:- -a first drive belt; -a compound double pulley having a first variable diameter pulley engaged by the first drive belt and a second variable diameter pulley engaged by a second drive belt, increases in the effective diameter of one pulley producing corresponding reduction in the effective diameter of the other pulley; -a third spring-loaded variable diameter pulley also engaging the second drive belt, and -a control actuator for varying the effective diameters of the first and second drive pulleys thus varying the overall ratio of the belt drive.
The compound pulley is moved by the control actuator in an arc.
Where the diameter of the third pulley is similar to the diameter to the first and second pulleys then the compound pulley preferable moves in an arc so that the distance between the axes of rotation of the compound pulley and the third pulley remains substantially constant.
However if the third pulley is significantly different in diameter to the first and second pulleys (sometimes necessary to achieve a particular speed ratio) then the axis about which the compound pulley is moved in the arc is advantageously offset from a line joining the axes of rotation of the compound pulley and the third pulley to take into account changes in the angle or wrap of the second belt around the second and third pulleys and disparity in the changes in the diameter of the pulleys as the compound pulley moves in the arc.
In such an arrangement, as the effective diameter of, for example, the first pulley increases the effective diameter of the second pulley decreases and the effective diameter of the third pulley increases in order to maintain the tension in the second drive belt.
Conveniently the compound pulley is pivotally mounted on an arm which is moved by the control actuator.
The control actuator is preferably a screw-threaded actuator which is rotated by an electric motor although other forms of actuation could be used.
To allow fine adjustments of the belt tension and pulley positions etc the mounting points of the control actuator andJor the pivotally mounted arm may be adjustable. Such adjustment can conveniently be provided by an actuator mount or arm which is screw-threadedly
adj ustable.
As indicated previously, a belt drive in accordance with the present invention is particularly suitable for driving a cleaning/separating fan in a combine harvester and the invention thus provides a combine harvester using a belt drive in accordance with the present invention to drive such a fan or for any other purpose.
One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:-Figure I shows a perspective view of a belt drive for a combine harvester cleaning/separating fan in accordance with the present invention; Figure 2 shows a cross-section through a compound variator pulley used in the drive of Figure I; Figure 3 shows a cross-section through a spring-load pulley used in the drive of Figure 1, and Figure 4 shows a cross-section through a combine cleaning/separating fan driven by the belt drive of the present invention.
Referring to the drawings a belt drive 10 in accordance with the present invention has a first drive belt II which is driven from a pulley shown in dotted detail 12 Drive belt II also engages a compound double pulley or variator 13 which has a first pulley 14 engaged by belt II and a second pulley IS engaged by a second drive belt 16. Second drive belt 16 also engages a third spring-loaded pulley 17 which is rotatable about an axis 18 and which acts as the output pulley for the belt drive.
Cross-sectional details of the compound double pulley 13 are shown in Figure 2. The pulley has two outer flanges 19 and 20 and a central moveable flange 21. The flanges 19 and 21 form the first pulley 14 and the flanges 20 and 21 the second pulley 15. The compound pulley 13 rotates about an axis 22 which is moveable along an arc A shown in Figure 1 50 that the distance between the axes of rotation 18 and 22 remains substantially constant as the distance between the axis 22 and the axis of rotation 23 of the pulley 12 varies. This movement of the pulley axis 22 about the arc A is achieved by a control actuator 24 which is connected with an arm 25 on which the compound pulley is mounted. The arm 25 pivots on a mounting plate 26 about an axis of pivoting 27 which lies generally on a line joining axes 18 and 22 The actuator 24 comprises a screw-thread actuator 28 having a rod 29 an end portion of which is screw-threaded and engaged by a nut located in a housing 30. This nut is in turn rotated by a gear wheel located in a housing 3 I and driven by an electric motor 32. Thus as the electric motor is rotated the rod 29 can be driven in and out of the housing 30 thus pivoting the arm 25 and the compound pulley I 3 about the arc A. Referring to Figure 2, with the first drive belt II occupying an outer position on the pulley 14, the second drive belt 16 occupies a smaller effective diameter position on the second pulley 15. As will be appreciated, if the compound pulley is moved along the arc A towards the actuator 24 by the electric motor 32 this forces the first drive belt to adopt a smaller effective diameter on pulley 14 as indicated by the arrow X in Figure 2 which in turn displaces the central flange 21 in the direction Z to force the second drive belt 16 radially outwardly to occupy a larger diameter effective position on the pulley 15 as indicated by the arrow Y. Similarly movement of the compound pulley 13 away from the actuator 24 using the electric motor 32 produces the reverse effect with the first drive belt II being moved to a larger effective diameter position and the second drive belt 16 thus being forced to a smaller effective diameter position.
As indicated previously, the third drive pulley 17 is spring loaded and has a fixed flange 33 and a moveable flange 34 against which a heavy coil spring 35 acts. This spring 35 is chosen to maintain a desired belt tension in the second drive belt 16 Thus when the effective diameter of the second pulley IS decreases the effective diameter of the third drive pulley 17 increases and vice versa in order to maintain the desired belt tension under the action of spring 35.
Since the compound pulley 13 is rotating about arc A, so that the axes of rotation 18 and 22 reniain substantially the same distance apart as the compound pulley moves along the arc A, this movement of the compound pulley has no effect on the belt tension so that the third pulley 17 responds by changing its effective pulley diameter solely in response to changes in the effective diameter of the second pulley 15 As will be appreciated, the lowest overall ratio of the belt drive is obtained when the first pulley 14 is operating at its largest possible effective diameter and the second pulley 15 at its smallest effective diameter with the third pulley 17 therefore again operating at a large effective diameter to maintain the belt tension. Similarly, highest possible ratio is obtained when the first pulley 14 is operating at its smallest effective diameter and the second pulley at its largest effective diameter with the third pulley 17 operating at a corresponding small effective diameter.
To provide for fine adjustments of the overall belt drive (e.g for belt tension, the relative position of the pulleys and manufacturing tolerances)the actuator 24 is adjustabty mounted on a mounting bracket 40 by nuts 41 which engage screw threaded portions 42 of rod 29 to allow adjustment of the effective length of the actuator 24. Also the effective length of arm is adjustable by a bolt 43 carried on an outer arm sleeve 25a which engages a peg 44 carried on an inner arm member 25b which slides in sleeve 25a. Peg 44 slides in a slot 45 in sleeve 25a so that turning of bolt 43 moves inner member 25b in and Out of sleeve 25a.
Screws 46 which engage inner member 25b via slots 47 in sleeve 25a can be used to firmly secure inner member 25b relative to sleeve 25a after adjustment with bolt 43.
Both the length of actuator 24 and arm 25 require adjustment to achieve the maximum speed range of the belt drive.
Figure 4 shows a cross-section through a so-called transverse fan for use in the combine harvester to clean and/or separate harvested grain. Typically the air produced by the fan 50 is directed through a stream of falling grain/chaff etc and blows off the lighter chaff/straw thus leaving the required grain.
The fan basically consists of a central drive shaft 51 on which the pulley I 7 is mounted. This drive shaft 51 carries a plurality of fan blades 52 which are supported from the shaft 51 on spaced support discs 53. The shaft 51 is itself supported from bearing blocks 54 earned in the side panelling of the combine. This type of transverse fan is the subject of the applicant's co-pending application number (case 7724) to which the reader is directed if further details are required.
As can be seen from figure 4, the moving flange 21 of compound pulley 13 aligns with the fixed flange 33 the third pulley 17. This is necessary if the alignment of belt 16 is to be maintained as the effective diameters of pulleys 14 and 17 vary throughout the speed range of the belt drive.
Typically the belt drive of the present invention can provide an output speed range of say 500r.p.rn to 1450rpm. an input speed of say 640r.p.m.
The above arrangement in which the compound pulley is moved in an arc A about a pivot axis 27 which lies on a line joining the pivot axes 18 and 22 in order to ensure that the distance between axes 18 and 22 remains substantially constant is suitable for belt drives in which the pulleys 14,15 and 17 are all of substantially the same diameter.
If the pulleys are forced to be of significantly different diameters (some times necessary in order to obtain a required overall drive ratio) the axis 27 about which the compound 13 is pivoted can advantageously be offset from the line joining the axes of rotation of the compound pulley and the third pulley so that as the compound pulley is pivoted the distance between axes 18 and 22 varies, This will compensate for the changes in the angle of wrap of the second belt 16 around pulleys 14 and 17 as the pulley 13 is pivoted and the fact that as the compound pulley is moved through its speed range the belt will change diameter on one pulley more than the other As will be appreciated, since the fan speed is varied solely by movement of the compound pulley by actuator 24 this variation in fan speed can easily and economically be obtained thus allowing adjustment of the combine for a wide range of different crops and conditions without requiring any assembly/disassembly of the belt drive. This contrasts with may current conibine belt drives which require, for example, a different pulley and/or belt to be fitted for very low speeds and/or have two positions for the belt on the drive pulley.

Claims (9)

  1. Claims A variable ratio belt drive comprising- -a first drive belt; -a
    compound double pulley having a first variable diameter pulley engaged by the first drive belt and a second variable diameter pulley engaged by a second drive belt, increases in the effective diameter of one pulley producing corresponding reductions in the effective diameter of the other pulley; -a third spring-loaded variable diameter pulley also engaging the second drive belt, and -a control actuator for varying the effective diameters of the first and second drive pulleys thus varying the overall ratio of the belt drive.
  2. 2. A drive according to claim I in which the diameter of the pulleys is similar and the compound pulley is moved by the control actuator in an arc so that the distance between the axes of rotation of the compound pulley and the third pulley remains substantially constant.
  3. 3 A drive according to claim I in which the diameter of the third pulley is significantly different to that of the first and second pulleys and the compound pulley is moved in an arc about an axis which is offset from a line joining the axes of rotation of the compound pulley and the third pulley to take into account changes in the angel or wrap of the second belt around the second and third pulleys and disparity in the changes in the diameter of the pulleys as the compound pulley moves in the arc.
  4. 4. A drive according to claim 2 or 3 in which the compound pulley is pivotally mounted on an arm which is moved by the control actuator.
  5. 5. A drive according to any one of claims I to 4 in which the control actuator is a screw-thread actuator which is rotated by an electric motor.
  6. 6. A drive according to any one of claims 2 to 5 in which the mounting of the control actuator and/or the pivotally mounted arm is adjustable to adjust the belt tension and pulley positions of the belt drive.
  7. 7 A combine harvester which includes a belt drive according to aiiy one of claims I to 6.
  8. 8. A combine according to claim 7 in which the belt drive drives a cleaning/separating fan
  9. 9. A belt drive constructed and arranged substantially as hereinbefore described with reference to and as shown in the accompanying drawings
GB0711030A 2007-06-08 2007-06-08 Variable ratio belt drives Withdrawn GB2449916A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0711030A GB2449916A (en) 2007-06-08 2007-06-08 Variable ratio belt drives

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0711030A GB2449916A (en) 2007-06-08 2007-06-08 Variable ratio belt drives

Publications (2)

Publication Number Publication Date
GB0711030D0 GB0711030D0 (en) 2007-07-18
GB2449916A true GB2449916A (en) 2008-12-10

Family

ID=38318973

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0711030A Withdrawn GB2449916A (en) 2007-06-08 2007-06-08 Variable ratio belt drives

Country Status (1)

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GB (1) GB2449916A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9175449B2 (en) 2013-03-13 2015-11-03 Caterpillar Paving Products Inc. Transmission system for transmitting power from engine to milling rotor in cold planer
US20160007526A1 (en) * 2013-03-13 2016-01-14 Husqvarna Ab Slip controlling belt tension system
EP3408550A4 (en) * 2016-01-29 2019-11-13 SRI International Inc. Compact infinitely variable transmission

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2251488A (en) * 1940-05-18 1941-08-05 Hucke Donald Rider Variable speed drive
US2881624A (en) * 1955-09-13 1959-04-14 Carlos J Cardona Variable drive
US2900832A (en) * 1956-01-16 1959-08-25 Allis Chalmers Mfg Co Double drive
US3152490A (en) * 1962-11-13 1964-10-13 Ford Motor Co Infinitely variable drive transmission
US3295384A (en) * 1964-12-23 1967-01-03 Deere & Co Variable speed belt drive for a vehicle
US3863514A (en) * 1973-01-15 1975-02-04 Beatrice Foods Co Belt-drive transmissions of amplified low/high ratio range for self-propelled surface vehicles
EP1172583A2 (en) * 2000-07-14 2002-01-16 Tecumseh Products Company Variable speed transmission and electronic speed control therefor

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2251488A (en) * 1940-05-18 1941-08-05 Hucke Donald Rider Variable speed drive
US2881624A (en) * 1955-09-13 1959-04-14 Carlos J Cardona Variable drive
US2900832A (en) * 1956-01-16 1959-08-25 Allis Chalmers Mfg Co Double drive
US3152490A (en) * 1962-11-13 1964-10-13 Ford Motor Co Infinitely variable drive transmission
US3295384A (en) * 1964-12-23 1967-01-03 Deere & Co Variable speed belt drive for a vehicle
US3863514A (en) * 1973-01-15 1975-02-04 Beatrice Foods Co Belt-drive transmissions of amplified low/high ratio range for self-propelled surface vehicles
EP1172583A2 (en) * 2000-07-14 2002-01-16 Tecumseh Products Company Variable speed transmission and electronic speed control therefor

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9175449B2 (en) 2013-03-13 2015-11-03 Caterpillar Paving Products Inc. Transmission system for transmitting power from engine to milling rotor in cold planer
US20160007526A1 (en) * 2013-03-13 2016-01-14 Husqvarna Ab Slip controlling belt tension system
US9730383B2 (en) * 2013-03-13 2017-08-15 Husqvarna Ab Slip controlling belt tension system
EP3408550A4 (en) * 2016-01-29 2019-11-13 SRI International Inc. Compact infinitely variable transmission
US10774907B2 (en) 2016-01-29 2020-09-15 Sri International Compact infinitely variable transmission

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Publication number Publication date
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Legal Events

Date Code Title Description
S13A Application for inventor to be mentioned (section 13(1)/patents act 1977)

Free format text: APPLICATION ALLOWED; IN A DECISION OF THE COMPTROLLER DATED 30 JULY 2009, THE APPLICATION FILED UNDER RULE 10(2) ON 22 JULY 2009 WAS ALLOWED. THE COMPTROLLER FOUND THAT CHARLES POLLOCK AND HELEN POLLOCK SHOULD ALSO BE MENTIONED AS INVENTORS IN THE PUBLISHED PATENT APPLICATION AND GRANTED PATENT FOR THE INVENTION AND DIRECTED, IN ACCORDANCE WITH RULE 10(1), THAT AN ADDENDUM SLIP MENTIONING THEM AS JOINT INVENTORS BE PREPARED FOR THE PUBLISHED PATENT APPLICATION AND GRANTED PATENT FOR THE INVENTION.

WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)