ZA200809032B - Transmission drive chain belt - Google Patents

Description

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FIELD OF THE INVENTION

[0001] This invention relates to a belt chain for driving a continuously or infinitely variable transmission (IVT) and more particularly to an improved drive belt for a number of the IVT embodiments disclosed in the specification of South African patent application No. 2007/07626. The full description of the relevant IVT embodiments which are described in South African patent application No. 2007/07626 are incorporated herein by reference.

SUMMARY OF THE INVENTION

[0002] An endless IVT transmission drive chain belt according to the invention comprises a chain belt of a predetermined width with the end portions of the link pins extending from and free of the edges of the belt with their ends flattened at an angle to the axes of the pins.

[0003] The link pins of the belt may each be identical two component composite pins with each component having an arcuate face with the arcuate faces of the two components facing and in line contact with each other over the length of the pin, in use, and a flat face opposite the arcuate face.

[0004] The link pin holes in the link plates may be substantially circular with flattened circumferential portions of the holes, towards the ends of the link plates, on which the flat face of one of the pin components bears in use.

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[0005] A circle which circumscribes a composite link pin of the belt may have a d diameter equivalent to the hole in the link plates in which it is located, in use, with - the pin diameter being adequate for resisting bending moments applied to it, in use.

[0006] The projecting end portions of the composite link pins may be coned onto the pin axis with the apex of the cone ends being flattened at an angle to the axes of the pins. The cone angle of the link pins may be 40° and the angle of the flat ends of the pins may be 27°.

[0007] The belt may be a composite belt composed of two chain belt components which are located on common link pins with a cylindrical spacer on the link pins bearing on and separating the two belt components. The spacers are preferably made from a suitable lightweight plastics material.

[0008] The link plates in each chain row of each chain belt component may include projecting tooth-like projections on a common upper or lower side of the belt link plates to collectively, in each row, define composite teeth for engagement with a compatible chain belt drive sprocket.

[0009] The term “chain belt” in this specification is to be taken to mean a chain which includes a large number of chain link plates which are arranged side by side in transverse rows in the belt with the end portions of the link plates of each row interleaved with those of adjacent rows and, link pins which pass through

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) aligned holes in the overlapped portions of the link plates in each row. An

J example of the link plate arrangement of such a chain belt is illustrated in Figure - 1 of the drawings of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Embodiments of the invention are now described by way of non-limiting examples only with reference to the drawings in which :

Figure 1 is an isometric view of the transmission drive chain belt of the invention shown driving the dual drive and belt tensioning arrangement of Figures 40 to 45 of South African patent application No. 2007/07626,

Figure 2 is a front elevation of one of the chain links of Figures 5 to 7,

Figure 3 is a front elevation of one of two link pin components of the composite link pins illustrated in Figures 1 and 5 to 7,

Figure 4 is an end elevation as seen from the right in Figure 3 of the Figure 3 link pin component,

Figure 5 is a front elevation of a fragment of the length of the Figure 1 chain illustrating the composite link pins of the chain, :

Figure 6 is a plan view of the Figure 5 chain fragment,

Figure 7 is an isometric view from above and one side of the chain fragment of

Figures 5 and 6,

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Figure 8 is a front elevation of one of the two dual drive chain pulleys for use with

J the chain of the invention, d Figure 9 is a side elevation of the Figure 8 chain drive pulley shown sectioned on the line 9-9 in Figure 8,

Figure 10 is an isometric view from above and one side of the pulley of Figures 8 and 9,

Figure 11 is an enlargement of the circled portion of the chain pulley of Figure 10,

Figure 12 is a front elevation of one of the two types of chain link used in a second embodiment of the drive chain of the invention,

Figure 13 is a front elevation of the second type of chain link used with the second embodiment of the chain,

Figure 14 is an isometric view from above and one side of the chain fragment of the second embodiment of the chain of the invention, .

Figure 15 is an isometric view from one side and below of the chain fragment of

Figure 14,

Figure 16 is an isometric view of one of the two chain drive pulleys for use with the second embodiment of the drive chain of the invention,

Figure 17 is a front elevation of the drive pulley of Figure 16 shown in engagement with a fragment of the second embodiment of the drive chain of the invention,

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Figure 18 illustrates a fragment of a ratio changing disc as used with the second d embodiment of the drive chain shown in its low ratio position between the discs, d Figure 19 is a view similar to that of Figure 18 with the chain fragment shown in its high ratio position between the ratio changing discs,

Figure 20 is substantially the same as that of Figure 18 with the chain shown in its low ratio position between the ratio changing discs,

Figure 21 is a side elevation of a side portion of the second embodiment of the chain with its link pin engaged in a groove on the ratio changing disc of an IVT, and

Figure 22 is a plan view shown sectioned on the line 22-22 of Figure 20 of two of the composite chain links of the invention shown engaged in chain grooves on the ratio changing disc of Figure 20.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The dual drive IVT shown schematically in Figure 1 is fully described with reference to Figures 40 to 45 of South African patent application No. 2007/07626.

[0012] One embodiment of the drive chain belt 10 of the invention is shown in

Figure 1 to be engaged with and on the chain engaging components of the IVT 12 shown in Figure 1.

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[0013] The chain engaging components include a pair of facing ratio changing : discs 14, only one of which is shown in the drawing, a pair of chain drive pulleys

J 16, a chain tensioning idler roller 18 and a pair of chain throat defining idler rollers 20.

[0014] The drive chain is composed of identical link plates 22, which are shaped as shown in Figure 2, and composite two-component link pins 24 as most clearly seen in Figure 7. Figure 5 illustrates a variation of the pins 24 which is discussed below.

[0015] The composite link pins 24 comprise two identical components of which one is shown in Figures 3 and 4. Each of the components has an arcuate face and an opposite flat face as shown in Figure 4. The ends 30 of the pin : components are, when the components are arranged with their arcuate faces 26 in abutment on the centreline of the composite pins 24, as shown in Figure 7, coned onto the centreline of the composite pin at an angle of 40°, as shown in

Figure 3. The cone tips 32 are then flattened to an angle of 27°, as shown in

Figure 3, with this angle corresponding to the taper angle of the ratio changing discs 14 and the bases of the series of grooves 34 in their facing faces.

The grooved faces of the ratio changing discs 14 are of the type which are : described with reference to Figures 22 and 23 of the dual drive IVT shown schematically in Figure 1 and are fully described with reference to Figures 40 to 45 of South African patent application No. 2007/07626.

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[0016] Returning to Figure 2, it is seen that the drive chain link plates 22 each - carry two substantially circular holes 36 which have flattened circumferential . portions opposite each other. The link pin plates 22 are overlapped with each other over the length of the chain as shown in Figures 5 to 7 and the composite link pins are slid through the aligned link plate holes 36 with their arcuate faces 26 in line contact with each other and their flattened surfaces 28 bearing on the flattened circumferential portion of one of the link plate holes 36.

[0017] The coned ends of the link pins 24 project outwardly from and free of the outer surfaces of the link plates 22 to define ratio changing disc 14 drive pins ; which are releasably engageable in the ratio changing discs 14 series 34 pin engaging grooves. The projecting coned ends of the pins are crucial to the drive chain of this invention.

[0018] In use, as the radius of a curved portion of the drive chain 10 as it passes over the facing tapered faces of the ratio changing discs 14, the chain drive pulley 16, the chain tensioning roller 18 and the chain throat idler rollers 20 the radius of curvature of the chain over these components varies considerably, as shown in Figure 1. Additionally the chain curvature problem is compounded by its various radius of curvature over the components being in opposite directions.

This obviously requires that the drive chain 10 must be capable of folding through a large number of various radii in opposite directions during operation of the IVT which is driven by the chain 10.

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[0019] The above chain flexation is achieved by the arcuate faces of the : composite link pins 24 rocking on each other and the angle of inclination of the d flattened surfaces of the chain link holes 36 being more or less inclined to a greater or lesser degree relatively to each other. Additionally the arcuate faces 26 could be made to have a greater or lesser degree of curvature than the portion of the faces above or below the pin axes. This is illustrated in Figure 5 where it is shown that the lower portions of the link pins have a lesser radius of curvature than that above the pin axis to enable the chain to fiex into a far tighter radius than shown in Figure 5 and a lesser degree of curvature while flexing in the opposite direction.

[0020] It is seen from Figure 2 that the upper surface of the link plate 22 is curved at a radius of R1 while the lower surface is curved at a radius of R2. The purpose of these curves is to ensure that in whichever way the Figure 5 chain is folded, for example downwardly as shown in the drawing, the combined R2 radii 15 . of the link plates will provide a large R2 radius degree of curvature while when the link plates are folded upwardly in the opposite direction a combined curvature of R1 will be provided for the entire portion of that belt passing over the particular rotatable component in the system. The flattened 27° portion 32 of the end cones on opposite ends of the pin 24 will provide a small contact area of the pin end with the base of the groove in which it is engaged on the ratio changing discs : 14. The full contact of the pin 24 ends with the ratio changing discs 14 is

P.21928/bit oy described below in connection with the second embodiment of the drive chain iE belt of the invention. : [0021] The dual drive chain drive pulley 16 as shown in Figures 8 and 9 correspond in function to the drive pulleys 14 and 14" of Figures 40 to 45 of 2007/07626.

[0022] The dual drive pulleys 16 each include a cylindrical body 44, a splined bore 46 and chain belt 10 engaging side walls 48. The inner surfaces of the side walls 48 are upwardly and outwardly tapered at an angle of 27° which corresponds to the angle of taper of the faces of the ratio changing discs and the flattened tips 32 of the composite link pins 24. As is shown in Figure 9 the inner faces 50 of the side walls 48 of the drive pulley 16 are outwardly stepped at 52.

The radius of the outer surface of the cylindrical body 44 of the pulley has a radius R2, as shown in the drawings.

[0023] The portions of the side walls 48 of the pulley 16 below the steps 52 include recesses 54 which extend downwardly from the step, as shown in Figure 11. The recesses 54 are shaped as shown in the drawing to include two downward lobes in which the spread inner curved surfaces of the drive chain belt 10 composite link pin components 24 are engageable to be driven by the pulley 16. It is obviously necessary, that the recesses 54 be separated from each other by a fixed distance P2 as shown in Figure 11 which corresponds to the P2 pitch distance separating the composite link pins from each other as shown in Figure

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5. As mentioned above, the curved lower surfaces of the chain links are curved : on a radius R2 which corresponds to the radius of curvature of the outer surface - of the cylindrical body 44 of the pulley.

[0024] On a portion of the chain drive belt 10 entering the pulley between its side walls 48 the 27° angle tips of the link pins ride over the inner surfaces of the outwardly stepped upper portions of the side walls until the spread inner portions of the link pins nest in the chain engaging recesses 54 in the pulley 16 to be positively driven by the pulley 16 and so the ratio changing discs 14 which are engaged positively by the chain belt 10 composite link pins 24.

[0025] The chain tensioning idler roller 18, as seen in Figure 1, includes a purely cylindrical body over which the drive chain belt 10 is moved on the radius R1 of the roller, as shown in Figure 1, the R1 radius of the roller corresponds to the upper curved surface R1 of the link plates 22 as shown in Figure 2. The throat defining idler rollers 20 include, as seen in Figure 1, upwardly and outwardly tapered side walls which hold the two bites of the drive chain belt 10 in register with each other as portions of the chain enter and leave the ratio changing disc between the rollers 20. The outer diameter of the throat defining rollers 20 has the same R1 outer diameter as that of the chain tensioning idler 18.

[0026] The second embodiment of the drive chain belt 10 is illustrated in Figures 12 to 15.

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[0027] In this embodiment of the chain of the invention the drive chain belt 10

J includes two differently shaped link plates 56 and 58 as shown in Figures 12 and . 13. Features of these link plates which are common to the link plate 22 of the first embodiment of the chain are their R1 upper surfaces and the composite link pin holes 36 in which their flattened portions are parallel to each other as opposed to the inclined flattened portions of the link plates 22 of the first embodiment. The link plate 58 of Figure 13 varies from that of Figure 12 in that it includes a downwardly directed tooth-shaped formation 60.

[0028] As is shown in Figures 14 and 15, this embodiment of the chain belt of - : the invention consists of two belt portions 62 and 64 which are held together by connecting pins 66. The outer link plates of each chain portion are those of

Figure 12 which, as seen in Figure 15, provide end walls which hold the chain on dual drive sprockets as will be explained below. The belt portions 62 and 64 are held in their parallel spaced relationship by cylindrical spacers 68 which are located over the composite drive link pins 24. The chain link portion spacers 68 are conveniently made from a lightweight suitable plastics material such as nylon or the like to significantly reduce the weight of the chain which would otherwise be substantially heavier than that shown in the drawings by the links 58 extending from one outer edge of the chain to the other. The chain of the second embodiment of the invention is driven by dual drive sprockets, one of which is shown in Figures 16 and 17. The double sprocket 70 is composed of two sprockets 72 and 74 which are identically shaped as shown in the drawings and

P.21928/bjt are held in a spaced relationship which corresponds to the distance separating

J the two chain portions of the chain of Figures 14 and 15, by spacers 76 which are < located over pins, not shown, which pass through and are attached in one way or another to the sprockets 72 and 74 to hold them in their spaced relationship. The width of each of the sprockets correspond to the length of a portion of the stacked link plates 58 of the chain with the outer plates 56, as shown in Figure 15, riding on the outside of each of the sprockets 72 and 74.

[0029] Figure 17 illustrates the mating of the tooth-like formations 60 of the = stacked link plates 58 of each of the chain portions 62 and 64 of the chain belt with each of the sprockets 72 and 74,

[0030] Figures 18 and 19 illustrate the operation of the composite link pins in moving between the low range position of the chain on the ratio changing discs of Figure 1 and the high range position of the chain in Figure 19. In these drawings the 27° tapered nose 32 of the composite link pins 24 ride on the base portion 78 of the ratio changing disc grooves between the Figures 18 and 19 positions of the chain. From these drawings it will be seen that in the low range position of the chain in Figure 18 in moving to the Figure 19 high range position the link pin 24 components rock on each other as the chain moves down the grooves to separate the lower ends of the link pin components until they are as fully spread from each other, as shown in Figure 15, by the radius of curvature of the abutting faces of the link pins and the flattened portions of the link pin holes in which they are located. The base portion of the grooves 78 are conveniently

P.21928/bjt made to widen as the chain is moved from the low to high ratio positions on the

J ratio changing discs 14. g [0031] Figure 20 is merely a repeat of Figure 18. Figure 21 is a side elevation of the chain and the ratio changing disc 14. Figure 21 is a side elevation illustrating fragments of the ratio changing disc 14 and chain 10 sectioned on the line 21-21 in Figure 20 with Figure 22 being a plan view of the chain fragment sectioned on the line 22-22 in Figure 20. Figure 21 lustrates the 27° flattened end of the drive portion of the composite link pin 24 engaged in a groove 80 on the ratio changing disc with its 27° flattened nose bearing on the 27° angle of taper of the ratio changing disc and the base 78 of its groove 80. From Figure 22 it is seen that with the flattened noses 32 of the composite link pins 24 bearing on the bases 78 of the grooves 80 the coned ends of the pins bear up against the 40° side walls of the grooves thus optimizing maximum force transfer from the composite driver links 24 to the ratio changing discs 14 during operation of the IVT.

[0032] The bases 78 of the ratio changing disc grooves 80 are coplanar with the ungrooved portion of the discs 14 so that the composite link pins 24 which are not engaged with grooves merely ride with their 27° noses resting on the 27° ungrooved surface of the ratio changing discs.

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Claims (1)

1. I : cL _ oe Page 15 CLAIMS

   1. An endless IVT transmission drive chain belt comprising a chain belt of a predetermined width with the end portions of the link pins extending from and free of the edges of the belt with their ends flattened at an angle to the axes of the pins,

   2. A drive chain belt as claimed in claim 1 wherein the link pins of the belt are each identical two component composite pins with each component having an arcuate face with the arcuate faces of the two components facing and in line contact with each other over the length of the pin, in use, and a flat face opposite the arcuate face. 3 A drive chain belt as claimed in claim 2 wherein the link pin holes in the link plates are substantially circular with flattened circumferential portions of the holes, towards the ends of the link plates, on which the flat face of one of the pin components bears in use.

   4. A drive chain belt as claimed in claim 3 wherein a circle which circumscribes a composite link pin of the belt has a diameter equivalent to the hole in the link plates in which it is located, in use, with the pin diameter being adequate for resisting bending moments applied to it, in use.

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   . : A drive chain belt as claimed in claim 4 wherein the projecting end - - portions of the composite link pins are coned onto the pin axis with the . apex of the cone ends being flattened at an angle to the axes of the pins.

   8. A drive chain belt as claimed in claim 5 wherein the cone angle of the link 5 pins is 40°.

   7. A drive chain belt as claimed in claim 5 wherein the angle of the flat ends of the pins is 27°.

   8. A drive chain belt as claimed in any one of the above claims wherein the belt is a composite belt composed of two chain belt components which are located on common link pins with a cylindrical spacer on the link pins bearing on and separating the two belt components.

   9. A drive chain belt as claimed in claim 8 wherein the spacers are made from a suitable lightweight plastics material.

   10. A drive chain belt as claimed in either one of claims 8 or 9 wherein the link : plates in each chain row of each chain belt component include projecting tooth-like projections on a common upper or lower side of the belt link plates to collectively, in each row, define composite teeth for engagement with a compatible chain belt drive sprocket.

   11. An endless IVT drive chain belt substantially as herein described with reference to and as illustrated in Figures 1 to 11.

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   . ~R_ ¥ 2008709032

   12. A endless IVT drive chain belt substantially as herein described with J reference to and as illustrated in Figures 12 to 22. DATED this 22" day of 5 2008 McCALLUM RADEMEYER & FREIMOND Patent Agents for the Applicant

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