CA2027902C - Flexible coupling for joining a driving member to a driven member - Google Patents
Flexible coupling for joining a driving member to a driven member Download PDFInfo
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- CA2027902C CA2027902C CA 2027902 CA2027902A CA2027902C CA 2027902 C CA2027902 C CA 2027902C CA 2027902 CA2027902 CA 2027902 CA 2027902 A CA2027902 A CA 2027902A CA 2027902 C CA2027902 C CA 2027902C
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Abstract
A flexible coupling mechanism for joining a driving shaft to a driven shaft includes first and second coupling members attachable to the shafts with each coupling member having an apparatus for connection to a disc or a disc pack. Such disc or disc pack may be attached to a solid intermediate coupling member, if desired. Each disc comprises a flexible member having a plurality of substantially symmetrical lobes which are affixed by a connector element joining each lobe to a torque transmitting member. The lobes are substantially symmetrical, having a pair of arms joined together adjacent a connector portion and means at the free ends of the arms are employed for connecting the lobes selectively to the driving, driven and intermediate (where such is employed) coupling members.
Description
FLEXIBLE COUPLING FOR JOINING A
DRIVING MEMBER TO A DRIVEN MEMBER
FIELD OF THE INVENTION
This invention relates in general to flexible couplings for joining a driving shaft to a driven Shaft, which may be misaligned relative to each other. More particularly, it relates to a coupling of the type employing one or more flexible disc elements which allow high axial and/or angular displacement between the shafts with increased torque transfer capability.
BACKGROUND OF THE INVENTION
When the axes of rotation of a driving and a driven shaft are not in alignment, there are a number of possible categories of such misalignment. One may be considered parallel offset, that is, where the axes are parallel to each other but spaced from one another in a transaxial dir~ction. Another may be considered angular offset, which is where ~tha axes are not parallel but intersect at an angle, although the axes may lie in parallel planes. The third is misalignmant in the axial direction.
Numerous coupling devices have been developed to transmit power from ar between two such shafts.
United States Patent No. 3,625,024 to Kikuchi, which issued December 7, 1971, and United States Patent No.
4,321,805, which issued to Bossler, Jr. on March 30, 1982, disclose such coupling devices (also known in the art as a "delta-flex°' coupling), but they are limited in their torque carxying capabilities because the arms of ' the °'delta°' used to txansmi~t torque are long and are subject to column buckling. Each of the ccauplings includes an element having a single beam or column with V-shaped elements at each of their ends for connection to driving and driven elements, such as xotatable shafts or _2_ hubs on such shafts. In each of these coupling elements, a beam or column which connects the "v", is susceptible to buckling under high torque loadings. This limits torque carrying capability.
Another type of coupling provided to transfer loads to accommodate axial misalignment or displacement between a driving and a driven shaft or displacement between a driving and a driven shaft is found in a series of patents currently assigned to the Assignee of the present invention. These are: United States Patents Nos. 4,282,723: 4,317,339 and 4,331,004, which issued on August 11, 1981, March 2, 1982 and May 25, 1982, respect~.vely, to Richard Schmidt.
In the Schmidt devices the actual coupling element, which is attached to hubs on each of a driving arid a driven shaft, includes an annular portion and two pairs of parallel arms. Whereas the arms themselves are parallel, the pairs are not symmetrical. The arms are sufficiently flexible to provide good axial and/or angular displacement to compensate for the misalignment.
However, there are inherent limitations in the design resulting in a limited ability to transfer high torque loads. This results from the fact 'that regardless of the direction of rotation, at least one pair of arms at all times is in compression without any compensating tensile component. The result is that under high torque conditions, the arm under compression is susceptible to buckling which, therefore, limits the load carrying capacity of the entire coupling element. The Schmidt type of device is also known as an open-end arm ar apen-link type of coupling.
Diaphragm-type couplings are known which permit large torque transmission, but are able only to handle slight angular misalignment on the order of 1/4 degrees to 1/3 degrees.
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Flat metal discs, such as the Formsprag type, are also well known, which offer high torque transmission, but are not capable of handling severe misalignments of driving and driven shafts. Also, in flat disc couplings, the phenomenon of °'fretting" occurs.
There are two types of "fretting", i.e. (a) nuta~ting around the bolt bearing washer, and (b) linear fretting, which occurs by the rubbing together of one disc on another (generating a shearing action) away from the connection area of the disc. As the disc material rubs, it oxidizes and disturbs the substrate, eventually propagating a fatigue crack. This is especially prevalent in discs having a thickness on the order of .015" to .090". Coating on such discs may extend their life, but they also deteriorate under the rubbing action.
I~t is an object of the present invention to provide a coupling mechanism capable of transmitting high torque loads whale compensating fax axial and/or angular misalignment.
Tt is another object of the present invention to provide a coupling mechanism which is capable of 'transferring torque loads in shear rather than either tension or compression alone, to approximate a diaphragm--type performance, while permitting higher angular misalignment, and axial displacement, both continuous and intermittent.
Still another object of the present invention is to provide a coupling mechanism which is capable of offsetting compression loads in each torque transmitting member by a tensian load.
A still further abject is to provide a coupling which eliminates fretting effects and being fatigue adjacent to the means of attachment.
An added object is to provide a coupling which can, in unidirectional applications, be assembled to minimize fretting by placing all attachment elements such as lobes in compressionp or alternatively to maximize torque carrying capacity by placing all lobes in tension.
An additional object is to provide a constant velocity coupling of a non-lubricated type.
SUMMARY OF THE TNVENTTON
The coupling device of the invention includes a flexible coupling disc element or elements for use in joining a driving member to a driven member, which members may be misaligned. Each flexible coupling disc element is formed into a plurality of lobes which are interconnected by connector elements, which can take various forms. In one preferred form, the lobes are spaced from an inner ring (or hub portion) or outer ring by generally radially extending connector elements. Each lobe has a pair of arms joined together adjacent the connector. They extend away from the connector in opposite circumferential directions, and terminate in free finds. This type of structure can be connected to driving and driven members in such manner as to cause force or torque transmission through the disc with shear loading on the connector element or tensile or compressive loading between the free ends of the lobes.
There are means at the free ends for connecting the lobes selectively either to the driving and/or 'the driven members.
The coupling device may include a first and a second coupling member, respectively mounted to driving and driven shafts. At least one intermediate flexible disc element is preferably located between the coupling members in the preferred embodiment, to which members the other flexible disc members are also mounted. In one form of the invention each coupling member has a plurality of radially extending arms. At the free ends of the arms of the lobes on the flexible disc element are means for connecting the arms selectively to radially ~~~~~~v~
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extending arms of the driving and driven coupling members, respectively.
The above and other features of the invention including various and novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that 'the particular misalignment compensating and high torque transmission coupling device embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in varied and numerous embodiments without departing from the spirit and scope of the invention.
BFtTEF DES(;RIPTION OF TIE DRAWINGS
Figure 1 is a coupling mechanism representing the prior art as taught in U.S. Patent 4,331,04 to Schmidt.
Figure 2 is an end view thereof as viewed from the left side of Figure 1.
Figure 3 is a flexible coupling member employed in the prior art Schmidt device.
Figure 3A is a view of a typical Formsprag type of flexible coupling member employed in the prior art.
Figure 4 is a flexible coupling member employed in the coupling mechanism of the invention.
Figure 5 is the same form of flexible coupling member as shown in Fig. 4 which can be employed in an alternative attachment arrangement of the coupling mechanism of the invention.
Figure 6 is another form of flexible coupling member which can be employed in the coupling mechanism of the invention.
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Figure 7 is a preferred form of flexible coupling member which can be employed in the coupling mechanism of the invention.
Figure 8 is an end view of a preferred form of the coupling mechanism of the invention employing the flexible coupling member shown in Figure 7.
Figure 9 is a side view of the coupling mechanism of Figure 8.
Figure l0 is an exploded perspective view of a l0 preferred form of the coupling mechanism of the invention employing an intermediate hub member.
Figure 11 is a view of a further form of flexible coupling member of the invention which eliminates the use of an inner ring element.
Figure 11A is a view of a further form of flexible coupling member of the invention which eliminates the use of an inner ring element.
Figure 12 is a view of a still further form of flexible coupling member of the invention in which there are two pairs of lobes used, and Figure 13 is a view of a still further form of flexible caupling member of t~ha invention in which twa connector elements are used per lobe.
DETAI:GED DESCRIPTION OF THE INVENTION
Referring to Figs. 1, 2 and 3, the prior art as represented by U.S. Patent 4,282,723 to Schmidt will now be described. The Schmidt device comprises a flexible coupling mechanism generally indicated as l0, which connects a first shaft 12, which can be a driving shaft (hereinafter sometimes referred to as Shaft A), to a second shaft 14, which can be a driven shaft (hereinafter sometimes referred to as Shaft B). Whereas the axis of rotation 16 of the shaft 12 and the axis of rotation 18 of shaft 14 appear to be aligned, they may suffer from w ~~ ~ ~~ aJ
-any one or combination of the misalignments described previously.
There are three basic members comprising the coupling mechanism 10. They include a first coupling member 20 (Fig. 1) and a second coupling member 22 which are adjustably secured to shafts 12 and Z4 respectively by set screws 24 or their equivalents. ~.n intermediate flexible membex, generally indicated at 26, is located between the first and second coupling members 20 and 22.
The first and second coupling members 20 and 22 are substantially identical to each other, consequentially, only one will be described here. Coupling member 20 includes a ring-shaped annular portion 28 having element receiving portions in the form of spider-like arms 30 Z5 extending radially outwardly and approximately 120 degrees apart, Whereas the first coupling member 20 has been described in general and shown in Figure 2 in salid lines, the companion coupling member 22 is shown for the most part in dotted lines.
The prior art intermediate flexible coupling member 26 will best be seen in Figure 3. It includes a generally ring-shaped annular portion 32 which has a cylindrical interior opening 34.
The intermediate member 26 also includes a first air of opposed generally para11e1 arm portions 36, 36' having attached ends 38, 38' respectively connected to the annular partion 32. each arm 36, 36' also has a free end 40, 40', respectively, provided with the openings 42, 42' respectively therein to receive a bolt to attach the arms 36, 36' to two of the three projecting spider-like arms 30 of the driving coupling member 20 as shown in Figures 1 and 2. The pair of free ends 40, 40' on the arms 36, 36°, respectively, are each connected to the spider arms as shown in the upper right and lower left quadrants of Figure 2, the connection being G 2 i , i ~~J~ ~~.~~;~~1~
-g_ accomplished by bolts 44. The remaining arm 30 (lower right quadrant of Figure 2) remains unconnected.
The intermediate member 26 further has a second pair of opposed generally parallel arm portions 56, 56', having attached ends 57, 57' respectively connecting such arm portions to the annular portion 32. Each arzn 56, 5E>' also has a free end 54, 54' respectively, provided with the openings 52, 52' respectively, therein to receive a bolt to attach the arms 56, 56' to two of the three projecting spider-like arms 33 of the driven coupling member 22, as shown in Figures Z and 2. The pair of free ends 54, 54' on the arms 56, 56' respectively, are each connected to the spider arms 33 as shown in the lower right and upper left quadrants of Figure 2, the connection being accomplished by bolts 43. The remaining arm 33 (upper right quadrant of Figure 2) of the driven coupling member remains unconnected.
Tn operation, the driving shaft 12 transmits torque through coupling member 20, the arm 30, to arm portion 3~ of the intermediate member 26 (assuming a counter-clockwise rotation as shown in figures 2 and 3) through the bolt connection. Tha torque is then transmitted through the halt connection. The torque is than transmitted through the attached ends 38 and 57 to arm 56 and via arm 33 of the driven coupling member 22 to the shaft 14. At the same time, torque is also transmitted through arm 30 to arm 36 and end 38' to ring portion 32 and via end 57' to arm 56' and via another arm 33 and second coupling member 22 to shaft 14.
With the direction of rotation being counter-clockwise as viewed in Figures 2 and 3, as indicated by the arrows, the arm is in tension and the arm 36' is in compression, as indicated respectively by the letters "T"
and "~'° in Figure 3. Also, the arm 55 is in tension and the arm 56° is in compression as indicated by the letters T and C in Figure 3. xn other words, the coupling member ~7 a .
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20 pulls the arm 36 and pushes the arm 36' by means of the bolts which pass through the free ends 40, 40' of the arms 36, 36', respectively. This renders arm 36' susceptible to columnar buckling, and thus limits high torque transmission. Also, the arm 56 is in tension and the arm 56' being in compression is also susceptible to columnar buckling. The foregoing shortcoming of the Schmidt coupling is one of the aspects which the present invention intends to improve upon.
While only a sketchy description of the apparatus and function disclosed by Schmidt has been given reference should be had to the patent cited for a more complete description of the function as well as haw it behaves in transmitting torque between misaligned .
shafts. Tt should be noted that as described above the spider arm 30 in the lower right-hand quadrant of Figure 2 is unconnected to the intermediate coupling member.
The spider arm 33, which is part of the second coupling member 22 and shown in the upper right-hand quadrant of Figure 2, is also coupled.
As shown in Figure 3A, another type of prior art device is the Formsprag type of intermediate flexible member which can be used singly or in a pack. The flexible member may be in the form of a metal flexible disc 26' having a circular opening 34' and provided with four holes 42'°, 42 " ', 52'° and 52 " ' for receiving bolts to be mounted to a driving and driven shaft coupling element. The convention mentioned abave is used, i.e. the connection to the driving shaft is shown by the letter "A" and the connection to the driven shaft is shown by the letter "B". Portions of the disc 26' are respectively placed in tension and in compression, assuming a counter-clockwise driving motion as shown by the arrow in Figure 3A. The tensile and compressive forces are indicated by the letters '°T°' and "C".
Although in such a type of device the sides in tension E
~S ~~ N 3 restrain the sides in compression from collapsing because of the geometry to obtain good torque transmission, there is very limited ability to accept angular misalignment.
This is another feature found in the prior art which the invention is intended to overcome.
In applicant's invention the use of lobes as shown in Schmid~t is also found to be advantageous, but there is provided in connector element to each lobe to interconnect them which is positioned between the ends of the lobes to reduce the column length. ~bviously a halfway positioning is optimum. This provides a buckling constraint. The column length is the distance between the connecting bolt or washer outer diameter, and the inner end of the connector neck, instead of the entire length of the lobe arm as shown in the Schmidt device.
This effectively reduces the column length subject to buckling by 2/3rds, but reduces the effective flexing ram by only 50%. A lobe/connector arrangement is thus preferred to abtain more torque. It is thus found that the shorter the length of the column arm, the more torque can be transmitted. Another feature of the invention is the use of an annular ring element to provide load sharing by distributing the torque transmittal forces.
As shown in :Figure 4 the teachings of the invention may be applied to a flexible coupling disc 126 which has two lobes 130 and 140 connected to an inner hub or force transmission ring 131 by connector portions 133 and 143, respectively. Although a ring is shown as the shape of hub 131 other shapes can be used, e.g. a diamond shape, as long as the function of force transmission between lobes is obtained. A third connector element is provided in the form of lug portions 135 and 137; also connected to the force transmission ring 131. Lobe 130 has bolt holes 136 and 13~ at its ends, and lobe 140 has bolt holes 142 and 144 at its ends. Lug 135 is provided with bolt hole 134 and lug 137 is provided with bolt hale 139. The connection of the flexible coupling is shown by convention as being to driver shaft A and driven shaft B
by placement of the letters "A" and ''B" in the bolt holes as shown in Figure 4. With the direction of rotation of the coupling member being clockwise as indicated in Figure 4, both ends of lobe 130 are placed in compression and both ends of lobe 140 are placed in tension, The lugs 135 arid 137 are placed in shear. Forces are thus balanced out to obtain higher torque transmission, i.e.
the shear and tension forces in lobe 140 and lugs 135 and 137 balance out the compression forces in lobe 130 to prevent column buckling.
To eliminate columnar loading entirely~an intermediate coupling member can be used (as described in more detail hereafter), which is illustrated in Figure 5.
Flexible coupling disc 126' has two lobes 130° and 140°, which are connected by connector portions 133' and 143' respectively to the inner force transmission ring 131'.
Lobe 130' is provided with bolt holes 136' and 138° at its ends and lobe 140' is provided with bolt holes 142' and 144' at its ends. Lugs 135' and 137' are provided with bolt holes 134' and 139', respectively, and are connected to an intermediate hub as shown by the convention "I" placed in these bolt holes. By using an intermediate hub member at least one flexible coupling disc must be placed on each side of such intermediate hub for connection respectively to the driving and to the driven coupling member. Figure 5 shows a disc which has both of its lobes 130' and 140° connected to the driving member A, and another identical flexible coupling disc will have both of its lobes connected to the driven member B. These will be mounted on either side of the intermediate hub member and the lugs 135° and 137' of both of such discs would be affixed to the intermediate hub. Such an arrangement increases torque transmission still further since it is accomplished all in shear ~C~' ro ~ a~ rs similar to a diaphragm type of coupling. Tt is the shear forces generated at the connector portions 133' and 143' which cause force transmission and the disc lobes are not column loaded since they function essentially as "dead°' elements. The use of the intermediate hub allows for more misalignment, and misalignment conditions.
The connector portions and the central hub can be combined in mechanical function by the use of a series of connector bars as elements connecting the lobes. As shown in Figure 6 a flexible coupling disc 226 is formed with three lobes 230, 240 and 250 which are interconnected by three connector bars 235, 245 and 255, arranged in the form of a delta connection. In this arrangement radial bending due to torque transmission is eliminated. Obviously, other forms could be used, such as a Y shape, or even only two bars being joined at one lobe, or also a spoked type with bars joined at the center. The lobes are provided with bolt holes 232, 242 and 252 for connection to a driving hub, and holes 234, 244, and 254 for connection to a driven hub. With rotation in the counter-clockwise direction as shown in Figure 6 each of the lobes will be in tension and subjected to radial bending from torque. The bars function as torsion beams due to actions caused by angular and axial misalignment of the coupling hubs.
A preferred form of applicant's invention is shown in Figures 7, 8 and 9 in which a flexible coupling disc member 58 is used. As shown in Fig. 7 the disc 58 includes an inner hub portion 60, which is illustrated as being essentially circular in shape. As indicated previously the shape may be other forms such as for example, triangular, without departing from the scope of the invention. There are shown a plurality of symmetrical outer lobes 62, 63 and 64, respectively connected to the inner hub 60 via connector portions 65, 67 and 69. The lobe 62 has a pair of arms 75, 77 joined .
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together adjacent the radial connector 65 and extending away therefrom in opposite circumferential directions.
Similarly, the lobe 63 is provided with the arms 86, 87 adjacent the radial connector 67; and the lobe 64 is provided with the arms 96, 97 adjacent the radial connector 69. Each labs terminates in symmetrically arranged arms provided with mounting holes for bolts.
Thus lobe 62 has belt hales 7~, 70' in arms 75, 77 respectively; lobe 63 has bolt hales 80, 80' in arms 86, 87 respectively; and lobe 64 has bolt holes 90, 90° in arms 96, 97 respectively.
As will be seen in Figure 9 the discs 58 are used in a plurality to form a disc pack. Each of these discs may be relatively thin or thick, and are flat upon assembly. They may be made of any appropriate similar or dissimilar metallic or nonmetallic material. Also, as seen in Figures 9 the disc pack 158 serves as an intermediate coupling member (four individual flexible discs being shown, although any number can be used) which is bolted together between the first and second axially arranged coupling members 74 and 76 (shown as slightly misaligned 3n Figure 9).
As shown in Figure 8 the coupling member 74 is formed with three spider-like arms 102, 104 and 106 extending from a central hub 100 which contains a bore to accommodate the driver shaft 12. A set screw 82 is employed to secure the coupling member 74 to the driving shaft 112. In a similar manner, the driven coupling member 76 is formed with three spider-like arms 202, 204 and 206 extending from a central hub 200 containing a bore to accommodate the driven shaft 114. Bet screw 182 is provided to secure the coupling member 76 to the driven shaft 114. Although not shown, keyways and keys may be used in a well understood manner with the set screws lacking onto the keys themselves. Also, although a coupling member with "spider-like'° arms is shown, other i~ -.
shapes, e.g. round, could be employed, while still coming within the spirit and scope of the invention.
Figures 8 and 9 show the bolting arrangement.
A series of identical bolts 108 are used as described hereafter. A bolt 108 secures the arm 87 of lobe 63 to the arm 102 of the driving member 74 (as shown at the one oarlock position of Figure 8). Another bolt 108 secures the arm 75 of lobe 62 to the arm 104 of the driving member 74 {as shown at the 9 o'clock position of Figure 8). Still another bolt 108 secures the arm 97 of lobe 64 to the arm 106 of the driving member 74. Similarly, the arms 202, 204 and 206 of the driven member 76 are bolted to the arms 77, 96 and 86 of the lobes 63, 62 and 64, respectively. Thus, each lobe is attached to both the Z5 driver and the driven coupling members and is flexed in the process of being driven as shown in Figure 9.
Assuming a counter-clockwise direction Of rotation as shown by the arrow in Figure 8, lobes 62, 63 and 64 are all placed tn tension because their respective 2,0 arms 75, 87 and 97 are being pulled by the respective spider arms 104, 102 and 106. The respective connector portions 65, 67 and 69 (see Figure 7) are placed in shear. No columnar buckling can occur in this arrangement. If a cloc7twise direction of rotation were 25 chosen in Figure 8, the lobes 62, 63 and 64 would all be placed in compression because their respective arms 75, 87 and 97 are being pushed by the respective spider arms 104, 102 and 106. Fretting is inhibited due to the effect of compressive forces on the substrate of the 30 material.
In the preferred embodiment of the invention an intermediate hub is preferably used, as suggested lay the discussion attendant with the description of Figure 5.
The arrangement is shown in the exploded perspective view 35 of Figure 10. A driving shaft 312 has mounted to it the first coupling member 374, which has an outwardly ~~,~~'~~~f 3'J
extending hub 300 affixed to the shaft 312 by means of a key and set screw in a well known manner. A series of four (only three being seen in Figure 10) access holes 305 pass through the coupling member 374. Four bolts 308 are arranged to pass through the coupling member through appropriate holes for fastening to a first disc pack 358.
A11 of the bolts are assembled by means of a spacer washer 306 and nut 304: Each individual disc is formed in the manner shown in Figure 7. although four such discs are shown in Figure 10 for each disc pack, any number can be used. Each disc may be separated from the next one by means of a spacer (not shown). Disc pack 360 is constructed similar to disc pack 358. Three lobes 362, 363 and 364 are formed by the disc pack 358. Lobe la 362 is formed with through holes 370 and 372 at the ends of its arms; lobe 363 is formed with through holes 380 and 382 at the ends of its arms; arid lobe 364 is formed with through holes 390 and 392 at the ends of its arms.
Holts 308 pass through the holes 392, 390, 380 and 382 to fasten the lobes 363 and 364 to the driving coupling member 374. The lobo 362 is fastened to an intermediate hub 320. The hub 320 is generally square shaped and has a central opening 330. Formed on the outer surface of the hub 320 axe four bosses 322, 324, 326 and 328, each of which has a through hole to receive a bolt 308. The lobe 362 is fastened to the intermediate hub 320 by bolts passing through bosses 324 and 326 and through the holes 372 and 370, respectively. Tn a similar manner the lobe 462 of disc pack 360 is fastened to the intermediate hub 320 by bolts 308 passing through the bosses 322 and 328 , and through the holes in the ends of the arms of lobe 462. The lobes 463 and 464 of the disc pack 360 are fastened to the second coupling member 376 by means of bolts 308 passing through holes 307 in member 376 and through the appropriate holes in the lobes. The coupling member is in turn fastened to a driven shaft 314.
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>J i t3 fc4 Although only one intermediate hub is shown in this preferred embodiment, a series of intermediate hubs (associated with a series of flexible disc packs) may be employed to accommodate greater misalignments.
~'ith the coupling device of the invention as shown in Figure 10 employing an intermediate hub, the disc packs function in the manner of a "wish-bone°°, i.e.
flexing occurs in the active inner ring portions adjacent the lobes which are fastened to the intermediate hub.
ZO Fluxing in this manner greatly increases the flexing length, resulting in lower side forces, greater angular misalignment capability and predominately high axial displacements. These are permitted without compromising the torque transmitting ability of the device when compared to convoluted diaphragm and disc coupling. In Figures 5 and 12 the disc packs function in a manner of a "double wish-bona flex". The lobes which are fastened to the intermediate hub arc therefore either pulled or pushed when the coupling device is in operation, and their connector portions to the inner ring are subjected to shear forces. The lobes which are fastened to the driving or driven coupling member essentially are "dead'°
elements in 'the flex mode, but are a part of the torque transmission system since both ends of each lobe are fastened to the same member. 'there is essentially no flexure in these lobes and they do not bend. There is by this arrangement a greater ability to handle misalignment and greater ability to transfer torque, because it is handled in shear. Fretting action is eliminated as well as fatigue problems at the bolts because there is no bending of the arms of the lobes at the lobe end attachment points. None of the lobes are subject to column buckling.
Still other forms of discs may be used where an intermediate hub is employed. For example, in Figure 11, instead of an inner ring, the disc 558 is provided with .a, ~~''~~~~i an outer ring 560 having inwardly arranged lobes 562, 563 and 564. Lobes 562 and 563 are shown as being connected to the driving coupling member while the lobe 564 is connected t0 the intermediate hub. Companion discs or disc packs on the other side of the intermediate hub would have their lobes 562 and 563 connected to the driven coupling member. Tn such a coupling device there is no column buckling in the arms of the lobes, the majority of the torque load is carried in shear at the connecting portions of the lobes to the outer ring. 3n Figure Z2 there are four lobes 662, 663, 664 and 665 shown as being connected to an inner torque reaction ring 660 in the disc 658. With lobes connected as shown to the driving and the driven coupling members, the disc functions as a solid hinged gimbal and large angular misalignment is allowed. Where an intermediate hub is employed two of the lobes (e.g. the lobes ~.ndicated as being connected to ''B") would.be connected to the intermediate hub, and another disc or disc pack would be employed an the other side of 'the intermediate hub which would have two opposed lobes connected to the driving coupling member. This arrangement would allow for parallel misalignment as wall as angular misalignment.
For maximum torque transmission, the inner hub opening can be reduced to a small bore, to allow the solid clamping (as by means of a bolt) of the flexible disc (or disc pack) to the intermediate member. The attachment of the flexible disc in this manner acts as a constraint on plate buckling, which permits very high torque transmission at very high transient and continuous forms of misalignment. In still another arrangement a disc 758 could be employed as shown in Figure 13. The disc 758 is formed with an outer torque reaction ring 760 and an inner torque reaction ring 740. Three lobes 762, 763 and 764 are connected between the inner and outer rings.
When used with an intermediate hub the bolt connection is %Y, '3 7~ ~~ (~
~18-as shown in Figure 13, it being understood that a similar disc or disc pack would be located on the other side of the intermediate hub and be connected to the B or driven coupling member instead of the driving coupling member A.
Very high angular misalignment may be accommodated as well as at very high torc~ues. The connector portions of the label are subjected to double shear because of the use of inner and outer torsion rings. The °'wishpbone"
flexing as above described occurs at both the inner and outer ring connectians to the lobes.
It is clear that other arrangements of discs, and different combinations employing intermediate hubs may be employed, all within the spirit and scope of the present invention. For example, in those configurations which position the discs at the outside ands of the coupling (i.e, with the driver and driven hubs adjacent ane another), a part of the ring portions adjacent such lobes may be eliminated so that the ring assumes a '°C"
shape, i.e., with open ends (the lobes may also be shortened in length adjacent to the open part of the "C"). This allows the disc pack to be readily removed from the coupling device for easy replacement of discs without having to disassemble the driving or driven coupling member from the respective shafts to which they are coupled. Obviously this could be done with discs having an inner ring such as in Figs. 5, 7 and 12, an outer ring such as in Fig. 11, or where both inner and outer rings are used as in Fig. 13. Such a configuration is showm for example in Fig. 11A, wherein the disc 558 is provided with an outer ring 560, and an opening 559 is provided by shortening the lobes 563 and 562, thus forming the ring 560 into a "C°' shape.
DRIVING MEMBER TO A DRIVEN MEMBER
FIELD OF THE INVENTION
This invention relates in general to flexible couplings for joining a driving shaft to a driven Shaft, which may be misaligned relative to each other. More particularly, it relates to a coupling of the type employing one or more flexible disc elements which allow high axial and/or angular displacement between the shafts with increased torque transfer capability.
BACKGROUND OF THE INVENTION
When the axes of rotation of a driving and a driven shaft are not in alignment, there are a number of possible categories of such misalignment. One may be considered parallel offset, that is, where the axes are parallel to each other but spaced from one another in a transaxial dir~ction. Another may be considered angular offset, which is where ~tha axes are not parallel but intersect at an angle, although the axes may lie in parallel planes. The third is misalignmant in the axial direction.
Numerous coupling devices have been developed to transmit power from ar between two such shafts.
United States Patent No. 3,625,024 to Kikuchi, which issued December 7, 1971, and United States Patent No.
4,321,805, which issued to Bossler, Jr. on March 30, 1982, disclose such coupling devices (also known in the art as a "delta-flex°' coupling), but they are limited in their torque carxying capabilities because the arms of ' the °'delta°' used to txansmi~t torque are long and are subject to column buckling. Each of the ccauplings includes an element having a single beam or column with V-shaped elements at each of their ends for connection to driving and driven elements, such as xotatable shafts or _2_ hubs on such shafts. In each of these coupling elements, a beam or column which connects the "v", is susceptible to buckling under high torque loadings. This limits torque carrying capability.
Another type of coupling provided to transfer loads to accommodate axial misalignment or displacement between a driving and a driven shaft or displacement between a driving and a driven shaft is found in a series of patents currently assigned to the Assignee of the present invention. These are: United States Patents Nos. 4,282,723: 4,317,339 and 4,331,004, which issued on August 11, 1981, March 2, 1982 and May 25, 1982, respect~.vely, to Richard Schmidt.
In the Schmidt devices the actual coupling element, which is attached to hubs on each of a driving arid a driven shaft, includes an annular portion and two pairs of parallel arms. Whereas the arms themselves are parallel, the pairs are not symmetrical. The arms are sufficiently flexible to provide good axial and/or angular displacement to compensate for the misalignment.
However, there are inherent limitations in the design resulting in a limited ability to transfer high torque loads. This results from the fact 'that regardless of the direction of rotation, at least one pair of arms at all times is in compression without any compensating tensile component. The result is that under high torque conditions, the arm under compression is susceptible to buckling which, therefore, limits the load carrying capacity of the entire coupling element. The Schmidt type of device is also known as an open-end arm ar apen-link type of coupling.
Diaphragm-type couplings are known which permit large torque transmission, but are able only to handle slight angular misalignment on the order of 1/4 degrees to 1/3 degrees.
~~~~~ ~i~~~~
Flat metal discs, such as the Formsprag type, are also well known, which offer high torque transmission, but are not capable of handling severe misalignments of driving and driven shafts. Also, in flat disc couplings, the phenomenon of °'fretting" occurs.
There are two types of "fretting", i.e. (a) nuta~ting around the bolt bearing washer, and (b) linear fretting, which occurs by the rubbing together of one disc on another (generating a shearing action) away from the connection area of the disc. As the disc material rubs, it oxidizes and disturbs the substrate, eventually propagating a fatigue crack. This is especially prevalent in discs having a thickness on the order of .015" to .090". Coating on such discs may extend their life, but they also deteriorate under the rubbing action.
I~t is an object of the present invention to provide a coupling mechanism capable of transmitting high torque loads whale compensating fax axial and/or angular misalignment.
Tt is another object of the present invention to provide a coupling mechanism which is capable of 'transferring torque loads in shear rather than either tension or compression alone, to approximate a diaphragm--type performance, while permitting higher angular misalignment, and axial displacement, both continuous and intermittent.
Still another object of the present invention is to provide a coupling mechanism which is capable of offsetting compression loads in each torque transmitting member by a tensian load.
A still further abject is to provide a coupling which eliminates fretting effects and being fatigue adjacent to the means of attachment.
An added object is to provide a coupling which can, in unidirectional applications, be assembled to minimize fretting by placing all attachment elements such as lobes in compressionp or alternatively to maximize torque carrying capacity by placing all lobes in tension.
An additional object is to provide a constant velocity coupling of a non-lubricated type.
SUMMARY OF THE TNVENTTON
The coupling device of the invention includes a flexible coupling disc element or elements for use in joining a driving member to a driven member, which members may be misaligned. Each flexible coupling disc element is formed into a plurality of lobes which are interconnected by connector elements, which can take various forms. In one preferred form, the lobes are spaced from an inner ring (or hub portion) or outer ring by generally radially extending connector elements. Each lobe has a pair of arms joined together adjacent the connector. They extend away from the connector in opposite circumferential directions, and terminate in free finds. This type of structure can be connected to driving and driven members in such manner as to cause force or torque transmission through the disc with shear loading on the connector element or tensile or compressive loading between the free ends of the lobes.
There are means at the free ends for connecting the lobes selectively either to the driving and/or 'the driven members.
The coupling device may include a first and a second coupling member, respectively mounted to driving and driven shafts. At least one intermediate flexible disc element is preferably located between the coupling members in the preferred embodiment, to which members the other flexible disc members are also mounted. In one form of the invention each coupling member has a plurality of radially extending arms. At the free ends of the arms of the lobes on the flexible disc element are means for connecting the arms selectively to radially ~~~~~~v~
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extending arms of the driving and driven coupling members, respectively.
The above and other features of the invention including various and novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that 'the particular misalignment compensating and high torque transmission coupling device embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in varied and numerous embodiments without departing from the spirit and scope of the invention.
BFtTEF DES(;RIPTION OF TIE DRAWINGS
Figure 1 is a coupling mechanism representing the prior art as taught in U.S. Patent 4,331,04 to Schmidt.
Figure 2 is an end view thereof as viewed from the left side of Figure 1.
Figure 3 is a flexible coupling member employed in the prior art Schmidt device.
Figure 3A is a view of a typical Formsprag type of flexible coupling member employed in the prior art.
Figure 4 is a flexible coupling member employed in the coupling mechanism of the invention.
Figure 5 is the same form of flexible coupling member as shown in Fig. 4 which can be employed in an alternative attachment arrangement of the coupling mechanism of the invention.
Figure 6 is another form of flexible coupling member which can be employed in the coupling mechanism of the invention.
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Figure 7 is a preferred form of flexible coupling member which can be employed in the coupling mechanism of the invention.
Figure 8 is an end view of a preferred form of the coupling mechanism of the invention employing the flexible coupling member shown in Figure 7.
Figure 9 is a side view of the coupling mechanism of Figure 8.
Figure l0 is an exploded perspective view of a l0 preferred form of the coupling mechanism of the invention employing an intermediate hub member.
Figure 11 is a view of a further form of flexible coupling member of the invention which eliminates the use of an inner ring element.
Figure 11A is a view of a further form of flexible coupling member of the invention which eliminates the use of an inner ring element.
Figure 12 is a view of a still further form of flexible coupling member of the invention in which there are two pairs of lobes used, and Figure 13 is a view of a still further form of flexible caupling member of t~ha invention in which twa connector elements are used per lobe.
DETAI:GED DESCRIPTION OF THE INVENTION
Referring to Figs. 1, 2 and 3, the prior art as represented by U.S. Patent 4,282,723 to Schmidt will now be described. The Schmidt device comprises a flexible coupling mechanism generally indicated as l0, which connects a first shaft 12, which can be a driving shaft (hereinafter sometimes referred to as Shaft A), to a second shaft 14, which can be a driven shaft (hereinafter sometimes referred to as Shaft B). Whereas the axis of rotation 16 of the shaft 12 and the axis of rotation 18 of shaft 14 appear to be aligned, they may suffer from w ~~ ~ ~~ aJ
-any one or combination of the misalignments described previously.
There are three basic members comprising the coupling mechanism 10. They include a first coupling member 20 (Fig. 1) and a second coupling member 22 which are adjustably secured to shafts 12 and Z4 respectively by set screws 24 or their equivalents. ~.n intermediate flexible membex, generally indicated at 26, is located between the first and second coupling members 20 and 22.
The first and second coupling members 20 and 22 are substantially identical to each other, consequentially, only one will be described here. Coupling member 20 includes a ring-shaped annular portion 28 having element receiving portions in the form of spider-like arms 30 Z5 extending radially outwardly and approximately 120 degrees apart, Whereas the first coupling member 20 has been described in general and shown in Figure 2 in salid lines, the companion coupling member 22 is shown for the most part in dotted lines.
The prior art intermediate flexible coupling member 26 will best be seen in Figure 3. It includes a generally ring-shaped annular portion 32 which has a cylindrical interior opening 34.
The intermediate member 26 also includes a first air of opposed generally para11e1 arm portions 36, 36' having attached ends 38, 38' respectively connected to the annular partion 32. each arm 36, 36' also has a free end 40, 40', respectively, provided with the openings 42, 42' respectively therein to receive a bolt to attach the arms 36, 36' to two of the three projecting spider-like arms 30 of the driving coupling member 20 as shown in Figures 1 and 2. The pair of free ends 40, 40' on the arms 36, 36°, respectively, are each connected to the spider arms as shown in the upper right and lower left quadrants of Figure 2, the connection being G 2 i , i ~~J~ ~~.~~;~~1~
-g_ accomplished by bolts 44. The remaining arm 30 (lower right quadrant of Figure 2) remains unconnected.
The intermediate member 26 further has a second pair of opposed generally parallel arm portions 56, 56', having attached ends 57, 57' respectively connecting such arm portions to the annular portion 32. Each arzn 56, 5E>' also has a free end 54, 54' respectively, provided with the openings 52, 52' respectively, therein to receive a bolt to attach the arms 56, 56' to two of the three projecting spider-like arms 33 of the driven coupling member 22, as shown in Figures Z and 2. The pair of free ends 54, 54' on the arms 56, 56' respectively, are each connected to the spider arms 33 as shown in the lower right and upper left quadrants of Figure 2, the connection being accomplished by bolts 43. The remaining arm 33 (upper right quadrant of Figure 2) of the driven coupling member remains unconnected.
Tn operation, the driving shaft 12 transmits torque through coupling member 20, the arm 30, to arm portion 3~ of the intermediate member 26 (assuming a counter-clockwise rotation as shown in figures 2 and 3) through the bolt connection. Tha torque is then transmitted through the halt connection. The torque is than transmitted through the attached ends 38 and 57 to arm 56 and via arm 33 of the driven coupling member 22 to the shaft 14. At the same time, torque is also transmitted through arm 30 to arm 36 and end 38' to ring portion 32 and via end 57' to arm 56' and via another arm 33 and second coupling member 22 to shaft 14.
With the direction of rotation being counter-clockwise as viewed in Figures 2 and 3, as indicated by the arrows, the arm is in tension and the arm 36' is in compression, as indicated respectively by the letters "T"
and "~'° in Figure 3. Also, the arm 55 is in tension and the arm 56° is in compression as indicated by the letters T and C in Figure 3. xn other words, the coupling member ~7 a .
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20 pulls the arm 36 and pushes the arm 36' by means of the bolts which pass through the free ends 40, 40' of the arms 36, 36', respectively. This renders arm 36' susceptible to columnar buckling, and thus limits high torque transmission. Also, the arm 56 is in tension and the arm 56' being in compression is also susceptible to columnar buckling. The foregoing shortcoming of the Schmidt coupling is one of the aspects which the present invention intends to improve upon.
While only a sketchy description of the apparatus and function disclosed by Schmidt has been given reference should be had to the patent cited for a more complete description of the function as well as haw it behaves in transmitting torque between misaligned .
shafts. Tt should be noted that as described above the spider arm 30 in the lower right-hand quadrant of Figure 2 is unconnected to the intermediate coupling member.
The spider arm 33, which is part of the second coupling member 22 and shown in the upper right-hand quadrant of Figure 2, is also coupled.
As shown in Figure 3A, another type of prior art device is the Formsprag type of intermediate flexible member which can be used singly or in a pack. The flexible member may be in the form of a metal flexible disc 26' having a circular opening 34' and provided with four holes 42'°, 42 " ', 52'° and 52 " ' for receiving bolts to be mounted to a driving and driven shaft coupling element. The convention mentioned abave is used, i.e. the connection to the driving shaft is shown by the letter "A" and the connection to the driven shaft is shown by the letter "B". Portions of the disc 26' are respectively placed in tension and in compression, assuming a counter-clockwise driving motion as shown by the arrow in Figure 3A. The tensile and compressive forces are indicated by the letters '°T°' and "C".
Although in such a type of device the sides in tension E
~S ~~ N 3 restrain the sides in compression from collapsing because of the geometry to obtain good torque transmission, there is very limited ability to accept angular misalignment.
This is another feature found in the prior art which the invention is intended to overcome.
In applicant's invention the use of lobes as shown in Schmid~t is also found to be advantageous, but there is provided in connector element to each lobe to interconnect them which is positioned between the ends of the lobes to reduce the column length. ~bviously a halfway positioning is optimum. This provides a buckling constraint. The column length is the distance between the connecting bolt or washer outer diameter, and the inner end of the connector neck, instead of the entire length of the lobe arm as shown in the Schmidt device.
This effectively reduces the column length subject to buckling by 2/3rds, but reduces the effective flexing ram by only 50%. A lobe/connector arrangement is thus preferred to abtain more torque. It is thus found that the shorter the length of the column arm, the more torque can be transmitted. Another feature of the invention is the use of an annular ring element to provide load sharing by distributing the torque transmittal forces.
As shown in :Figure 4 the teachings of the invention may be applied to a flexible coupling disc 126 which has two lobes 130 and 140 connected to an inner hub or force transmission ring 131 by connector portions 133 and 143, respectively. Although a ring is shown as the shape of hub 131 other shapes can be used, e.g. a diamond shape, as long as the function of force transmission between lobes is obtained. A third connector element is provided in the form of lug portions 135 and 137; also connected to the force transmission ring 131. Lobe 130 has bolt holes 136 and 13~ at its ends, and lobe 140 has bolt holes 142 and 144 at its ends. Lug 135 is provided with bolt hole 134 and lug 137 is provided with bolt hale 139. The connection of the flexible coupling is shown by convention as being to driver shaft A and driven shaft B
by placement of the letters "A" and ''B" in the bolt holes as shown in Figure 4. With the direction of rotation of the coupling member being clockwise as indicated in Figure 4, both ends of lobe 130 are placed in compression and both ends of lobe 140 are placed in tension, The lugs 135 arid 137 are placed in shear. Forces are thus balanced out to obtain higher torque transmission, i.e.
the shear and tension forces in lobe 140 and lugs 135 and 137 balance out the compression forces in lobe 130 to prevent column buckling.
To eliminate columnar loading entirely~an intermediate coupling member can be used (as described in more detail hereafter), which is illustrated in Figure 5.
Flexible coupling disc 126' has two lobes 130° and 140°, which are connected by connector portions 133' and 143' respectively to the inner force transmission ring 131'.
Lobe 130' is provided with bolt holes 136' and 138° at its ends and lobe 140' is provided with bolt holes 142' and 144' at its ends. Lugs 135' and 137' are provided with bolt holes 134' and 139', respectively, and are connected to an intermediate hub as shown by the convention "I" placed in these bolt holes. By using an intermediate hub member at least one flexible coupling disc must be placed on each side of such intermediate hub for connection respectively to the driving and to the driven coupling member. Figure 5 shows a disc which has both of its lobes 130' and 140° connected to the driving member A, and another identical flexible coupling disc will have both of its lobes connected to the driven member B. These will be mounted on either side of the intermediate hub member and the lugs 135° and 137' of both of such discs would be affixed to the intermediate hub. Such an arrangement increases torque transmission still further since it is accomplished all in shear ~C~' ro ~ a~ rs similar to a diaphragm type of coupling. Tt is the shear forces generated at the connector portions 133' and 143' which cause force transmission and the disc lobes are not column loaded since they function essentially as "dead°' elements. The use of the intermediate hub allows for more misalignment, and misalignment conditions.
The connector portions and the central hub can be combined in mechanical function by the use of a series of connector bars as elements connecting the lobes. As shown in Figure 6 a flexible coupling disc 226 is formed with three lobes 230, 240 and 250 which are interconnected by three connector bars 235, 245 and 255, arranged in the form of a delta connection. In this arrangement radial bending due to torque transmission is eliminated. Obviously, other forms could be used, such as a Y shape, or even only two bars being joined at one lobe, or also a spoked type with bars joined at the center. The lobes are provided with bolt holes 232, 242 and 252 for connection to a driving hub, and holes 234, 244, and 254 for connection to a driven hub. With rotation in the counter-clockwise direction as shown in Figure 6 each of the lobes will be in tension and subjected to radial bending from torque. The bars function as torsion beams due to actions caused by angular and axial misalignment of the coupling hubs.
A preferred form of applicant's invention is shown in Figures 7, 8 and 9 in which a flexible coupling disc member 58 is used. As shown in Fig. 7 the disc 58 includes an inner hub portion 60, which is illustrated as being essentially circular in shape. As indicated previously the shape may be other forms such as for example, triangular, without departing from the scope of the invention. There are shown a plurality of symmetrical outer lobes 62, 63 and 64, respectively connected to the inner hub 60 via connector portions 65, 67 and 69. The lobe 62 has a pair of arms 75, 77 joined .
x: ~, l~~ ~ 'i i.l ~%
together adjacent the radial connector 65 and extending away therefrom in opposite circumferential directions.
Similarly, the lobe 63 is provided with the arms 86, 87 adjacent the radial connector 67; and the lobe 64 is provided with the arms 96, 97 adjacent the radial connector 69. Each labs terminates in symmetrically arranged arms provided with mounting holes for bolts.
Thus lobe 62 has belt hales 7~, 70' in arms 75, 77 respectively; lobe 63 has bolt hales 80, 80' in arms 86, 87 respectively; and lobe 64 has bolt holes 90, 90° in arms 96, 97 respectively.
As will be seen in Figure 9 the discs 58 are used in a plurality to form a disc pack. Each of these discs may be relatively thin or thick, and are flat upon assembly. They may be made of any appropriate similar or dissimilar metallic or nonmetallic material. Also, as seen in Figures 9 the disc pack 158 serves as an intermediate coupling member (four individual flexible discs being shown, although any number can be used) which is bolted together between the first and second axially arranged coupling members 74 and 76 (shown as slightly misaligned 3n Figure 9).
As shown in Figure 8 the coupling member 74 is formed with three spider-like arms 102, 104 and 106 extending from a central hub 100 which contains a bore to accommodate the driver shaft 12. A set screw 82 is employed to secure the coupling member 74 to the driving shaft 112. In a similar manner, the driven coupling member 76 is formed with three spider-like arms 202, 204 and 206 extending from a central hub 200 containing a bore to accommodate the driven shaft 114. Bet screw 182 is provided to secure the coupling member 76 to the driven shaft 114. Although not shown, keyways and keys may be used in a well understood manner with the set screws lacking onto the keys themselves. Also, although a coupling member with "spider-like'° arms is shown, other i~ -.
shapes, e.g. round, could be employed, while still coming within the spirit and scope of the invention.
Figures 8 and 9 show the bolting arrangement.
A series of identical bolts 108 are used as described hereafter. A bolt 108 secures the arm 87 of lobe 63 to the arm 102 of the driving member 74 (as shown at the one oarlock position of Figure 8). Another bolt 108 secures the arm 75 of lobe 62 to the arm 104 of the driving member 74 {as shown at the 9 o'clock position of Figure 8). Still another bolt 108 secures the arm 97 of lobe 64 to the arm 106 of the driving member 74. Similarly, the arms 202, 204 and 206 of the driven member 76 are bolted to the arms 77, 96 and 86 of the lobes 63, 62 and 64, respectively. Thus, each lobe is attached to both the Z5 driver and the driven coupling members and is flexed in the process of being driven as shown in Figure 9.
Assuming a counter-clockwise direction Of rotation as shown by the arrow in Figure 8, lobes 62, 63 and 64 are all placed tn tension because their respective 2,0 arms 75, 87 and 97 are being pulled by the respective spider arms 104, 102 and 106. The respective connector portions 65, 67 and 69 (see Figure 7) are placed in shear. No columnar buckling can occur in this arrangement. If a cloc7twise direction of rotation were 25 chosen in Figure 8, the lobes 62, 63 and 64 would all be placed in compression because their respective arms 75, 87 and 97 are being pushed by the respective spider arms 104, 102 and 106. Fretting is inhibited due to the effect of compressive forces on the substrate of the 30 material.
In the preferred embodiment of the invention an intermediate hub is preferably used, as suggested lay the discussion attendant with the description of Figure 5.
The arrangement is shown in the exploded perspective view 35 of Figure 10. A driving shaft 312 has mounted to it the first coupling member 374, which has an outwardly ~~,~~'~~~f 3'J
extending hub 300 affixed to the shaft 312 by means of a key and set screw in a well known manner. A series of four (only three being seen in Figure 10) access holes 305 pass through the coupling member 374. Four bolts 308 are arranged to pass through the coupling member through appropriate holes for fastening to a first disc pack 358.
A11 of the bolts are assembled by means of a spacer washer 306 and nut 304: Each individual disc is formed in the manner shown in Figure 7. although four such discs are shown in Figure 10 for each disc pack, any number can be used. Each disc may be separated from the next one by means of a spacer (not shown). Disc pack 360 is constructed similar to disc pack 358. Three lobes 362, 363 and 364 are formed by the disc pack 358. Lobe la 362 is formed with through holes 370 and 372 at the ends of its arms; lobe 363 is formed with through holes 380 and 382 at the ends of its arms; arid lobe 364 is formed with through holes 390 and 392 at the ends of its arms.
Holts 308 pass through the holes 392, 390, 380 and 382 to fasten the lobes 363 and 364 to the driving coupling member 374. The lobo 362 is fastened to an intermediate hub 320. The hub 320 is generally square shaped and has a central opening 330. Formed on the outer surface of the hub 320 axe four bosses 322, 324, 326 and 328, each of which has a through hole to receive a bolt 308. The lobe 362 is fastened to the intermediate hub 320 by bolts passing through bosses 324 and 326 and through the holes 372 and 370, respectively. Tn a similar manner the lobe 462 of disc pack 360 is fastened to the intermediate hub 320 by bolts 308 passing through the bosses 322 and 328 , and through the holes in the ends of the arms of lobe 462. The lobes 463 and 464 of the disc pack 360 are fastened to the second coupling member 376 by means of bolts 308 passing through holes 307 in member 376 and through the appropriate holes in the lobes. The coupling member is in turn fastened to a driven shaft 314.
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>J i t3 fc4 Although only one intermediate hub is shown in this preferred embodiment, a series of intermediate hubs (associated with a series of flexible disc packs) may be employed to accommodate greater misalignments.
~'ith the coupling device of the invention as shown in Figure 10 employing an intermediate hub, the disc packs function in the manner of a "wish-bone°°, i.e.
flexing occurs in the active inner ring portions adjacent the lobes which are fastened to the intermediate hub.
ZO Fluxing in this manner greatly increases the flexing length, resulting in lower side forces, greater angular misalignment capability and predominately high axial displacements. These are permitted without compromising the torque transmitting ability of the device when compared to convoluted diaphragm and disc coupling. In Figures 5 and 12 the disc packs function in a manner of a "double wish-bona flex". The lobes which are fastened to the intermediate hub arc therefore either pulled or pushed when the coupling device is in operation, and their connector portions to the inner ring are subjected to shear forces. The lobes which are fastened to the driving or driven coupling member essentially are "dead'°
elements in 'the flex mode, but are a part of the torque transmission system since both ends of each lobe are fastened to the same member. 'there is essentially no flexure in these lobes and they do not bend. There is by this arrangement a greater ability to handle misalignment and greater ability to transfer torque, because it is handled in shear. Fretting action is eliminated as well as fatigue problems at the bolts because there is no bending of the arms of the lobes at the lobe end attachment points. None of the lobes are subject to column buckling.
Still other forms of discs may be used where an intermediate hub is employed. For example, in Figure 11, instead of an inner ring, the disc 558 is provided with .a, ~~''~~~~i an outer ring 560 having inwardly arranged lobes 562, 563 and 564. Lobes 562 and 563 are shown as being connected to the driving coupling member while the lobe 564 is connected t0 the intermediate hub. Companion discs or disc packs on the other side of the intermediate hub would have their lobes 562 and 563 connected to the driven coupling member. Tn such a coupling device there is no column buckling in the arms of the lobes, the majority of the torque load is carried in shear at the connecting portions of the lobes to the outer ring. 3n Figure Z2 there are four lobes 662, 663, 664 and 665 shown as being connected to an inner torque reaction ring 660 in the disc 658. With lobes connected as shown to the driving and the driven coupling members, the disc functions as a solid hinged gimbal and large angular misalignment is allowed. Where an intermediate hub is employed two of the lobes (e.g. the lobes ~.ndicated as being connected to ''B") would.be connected to the intermediate hub, and another disc or disc pack would be employed an the other side of 'the intermediate hub which would have two opposed lobes connected to the driving coupling member. This arrangement would allow for parallel misalignment as wall as angular misalignment.
For maximum torque transmission, the inner hub opening can be reduced to a small bore, to allow the solid clamping (as by means of a bolt) of the flexible disc (or disc pack) to the intermediate member. The attachment of the flexible disc in this manner acts as a constraint on plate buckling, which permits very high torque transmission at very high transient and continuous forms of misalignment. In still another arrangement a disc 758 could be employed as shown in Figure 13. The disc 758 is formed with an outer torque reaction ring 760 and an inner torque reaction ring 740. Three lobes 762, 763 and 764 are connected between the inner and outer rings.
When used with an intermediate hub the bolt connection is %Y, '3 7~ ~~ (~
~18-as shown in Figure 13, it being understood that a similar disc or disc pack would be located on the other side of the intermediate hub and be connected to the B or driven coupling member instead of the driving coupling member A.
Very high angular misalignment may be accommodated as well as at very high torc~ues. The connector portions of the label are subjected to double shear because of the use of inner and outer torsion rings. The °'wishpbone"
flexing as above described occurs at both the inner and outer ring connectians to the lobes.
It is clear that other arrangements of discs, and different combinations employing intermediate hubs may be employed, all within the spirit and scope of the present invention. For example, in those configurations which position the discs at the outside ands of the coupling (i.e, with the driver and driven hubs adjacent ane another), a part of the ring portions adjacent such lobes may be eliminated so that the ring assumes a '°C"
shape, i.e., with open ends (the lobes may also be shortened in length adjacent to the open part of the "C"). This allows the disc pack to be readily removed from the coupling device for easy replacement of discs without having to disassemble the driving or driven coupling member from the respective shafts to which they are coupled. Obviously this could be done with discs having an inner ring such as in Figs. 5, 7 and 12, an outer ring such as in Fig. 11, or where both inner and outer rings are used as in Fig. 13. Such a configuration is showm for example in Fig. 11A, wherein the disc 558 is provided with an outer ring 560, and an opening 559 is provided by shortening the lobes 563 and 562, thus forming the ring 560 into a "C°' shape.
Claims (23)
1. A flexible disc-like coupling element, comprising:
(a) a hub portion at least partially defining and at least partially surrounding a central aperture, the hub portion comprising a radial dimension as defined from the central aperture;
(b) connector portion means for connecting a corresponding lobe to the hub portion;
(c) a plurality of lobes including each of the corresponding lobes which are spaced from the hub portion, each lobe consisting of a pair of substantially arcuate shaped arms joined together adjacent its corresponding connector portion means, extending away from one another in substantially opposite directions, and terminating in free ends; and (d) attachment means, proximate the free ends of the arms, for attaching the disc-like coupling element to a driving member and a driven member of a drive train apparatus, the attachment means being located at a substantially identical radial distance from the central aperture of the disc-like coupling element, the attachment means being configured to connect the disc-like coupling element in one of at least two configurations, a first configuration consisting of connecting the ends of both arms of one lobe to the driving member and connecting the ends of both arms of another lobe to the driven member, a second configuration consisting of connecting the end of one arm of a particular lobe to the driving member and connecting the end of the other arm of the particular lobe to the driven member.
(a) a hub portion at least partially defining and at least partially surrounding a central aperture, the hub portion comprising a radial dimension as defined from the central aperture;
(b) connector portion means for connecting a corresponding lobe to the hub portion;
(c) a plurality of lobes including each of the corresponding lobes which are spaced from the hub portion, each lobe consisting of a pair of substantially arcuate shaped arms joined together adjacent its corresponding connector portion means, extending away from one another in substantially opposite directions, and terminating in free ends; and (d) attachment means, proximate the free ends of the arms, for attaching the disc-like coupling element to a driving member and a driven member of a drive train apparatus, the attachment means being located at a substantially identical radial distance from the central aperture of the disc-like coupling element, the attachment means being configured to connect the disc-like coupling element in one of at least two configurations, a first configuration consisting of connecting the ends of both arms of one lobe to the driving member and connecting the ends of both arms of another lobe to the driven member, a second configuration consisting of connecting the end of one arm of a particular lobe to the driving member and connecting the end of the other arm of the particular lobe to the driven member.
2. The flexible disc-like coupling element of claim 1 wherein the hub portion comprises a radial dimension as defined from the central aperture, the hub portion further comprises means for flexing across the radial dimension within the plane of the disc-like coupling element, and each connector portion means is located and has a radial length between the hub portion and the corresponding lobe such that the corresponding lobe is substantially proximate the hub portion, each connector portion means being substantially circumferentially rigid across the radial dimension of the hub portion.
3. The flexible disc-like coupling element of claim 2 wherein the hub portion means for flexing comprises an arcuate member which forms an open-shaped hub portion.
4. The flexible disc-like coupling element of any one of claims 1, 2 or 3 wherein the hub portion comprises at least two members, each member having a first and a second end, the first end of one member being connected to the first end of the other member, the second ends of the at least two members being separated so that the at least two members form an open shape, and one of the connector portion means is located adjacent the connected first ends of the at least two members and another one of the connector portion means is located adjacent the second end of each member.
5. The flexible disc-like coupling element of claim 1 wherein the hub portion comprises at least three members which form a closed shape surrounding the central aperture, each member having two ends, each end of each member being connected to the end of another member, and one of the connector portion means is located adjacent each pair of connected member ends.
6. The flexible disc-like coupling element of claim 1 wherein the hub portion comprises a closed-shaped annulus member.
7. The flexible disc-like coupling element of claim 1 wherein the hub portion comprises a delta-shaped member.
8. The flexible disc-like coupling element of claim 1 wherein the hub portion comprises an inner hub portion, and the lobes are spaced outward from the inner hub portion outside the central aperture.
9. The flexible disc-like coupling element of claim 1 wherein the hub portion comprises an outer hub portion, and the lobes are spaced inward from the outer hub portion within the central aperture.
10. The flexible disc-like coupling element of claim 1 further comprising at least one lug portion connected to and extending away from the hub portion, each lug portion comprising attachment means for attaching the disc-like coupling element to other elements of the drive train apparatus.
11. A flexible coupling for joining a driving shaft to a driven shaft in a drive train apparatus of the type having a nominal axis of rotation, the flexible coupling comprising:
(a) first and second coupling means for attachment to the driving and the driven shafts, each coupling means including first and second mounting mechanisms located radially from the nominal axis of rotation; and (b) a flexible disc-like coupling element, comprising:
(i) a hub portion at least partially defining and at least partially surrounding a central aperture, the hub portion comprising a radial dimension as defined from the central aperture;
(ii) connector portion means for connecting a corresponding lobe to the hub portion;
(iii) a plurality of lobes including each of the corresponding lobes which are spaced from the hub portion, each lobe consisting of a pair of substantially arcuate shaped arms joined together adjacent its corresponding connector portion means, extending away from one another in substantially opposite directions, and terminating in free ends; and (iv) attachment means, proximate the free ends of the arms, far attaching the disc-like coupling element to the first and second coupling means, the attachment means being configured to connect the disc-like coupling element in a first and a second operational configuration, the first configuration consisting of connecting the ends of both arms of one lobe to the first coupling means and connecting the ends of both arms of another lobe t:o the second coupling means, the second configuration consisting of connecting the end of one arm of a particular lobe to the first coupling means and connecting the end of the other arm of the particular lobe to the second coupling means.
(a) first and second coupling means for attachment to the driving and the driven shafts, each coupling means including first and second mounting mechanisms located radially from the nominal axis of rotation; and (b) a flexible disc-like coupling element, comprising:
(i) a hub portion at least partially defining and at least partially surrounding a central aperture, the hub portion comprising a radial dimension as defined from the central aperture;
(ii) connector portion means for connecting a corresponding lobe to the hub portion;
(iii) a plurality of lobes including each of the corresponding lobes which are spaced from the hub portion, each lobe consisting of a pair of substantially arcuate shaped arms joined together adjacent its corresponding connector portion means, extending away from one another in substantially opposite directions, and terminating in free ends; and (iv) attachment means, proximate the free ends of the arms, far attaching the disc-like coupling element to the first and second coupling means, the attachment means being configured to connect the disc-like coupling element in a first and a second operational configuration, the first configuration consisting of connecting the ends of both arms of one lobe to the first coupling means and connecting the ends of both arms of another lobe t:o the second coupling means, the second configuration consisting of connecting the end of one arm of a particular lobe to the first coupling means and connecting the end of the other arm of the particular lobe to the second coupling means.
12. The flexible coupling of claim 11 wherein the flexible disc-like coupling element further comprises at least one lug portion connected to and extending away from the hub portion, each lug portion comprising attachment means for attaching the disc-like coupling element to other elements of the drive train apparatus.
13. The flexible coupling of claim 11 further comprising a plurality of disc-like coupling elements which are assembled to form a disc pack having a closed-shaped hub portion and which are located between the first and second coupling means, each disc-like coupling element overlying another disc-like coupling element of the disc pack such that the attachment means of each disc-like coupling element are substantially aligned with the attachment means of another disc-like coupling element.
14. The flexible coupling of claim 11 further comprising a plurality of disc-like coupling elements which are assembled to form a disc pack having an open-shaped hub portion and which are located between the first and second coupling means each disc-like coupling element overlying another disc-like coupling element of the disc pack such that the attachment means of each disc-like coupling element are substantially aligned with the attachment means of another disc-like coupling element.
15. The flexible coupling of claim 11 connected in the first configuration wherein both arms of a first lobe are connected respectively to the first and second mounting mechanisms of the first coupling means, and both arms of a second lobe are connected respectively to the first and second mounting mechanisms of the second coupling means.
16. The flexible coupling of claim 11 connected in the second configuration wherein one arm of a particular lobe is connected to the first mounting mechanism of first coupling means, and the other arm of the particular lobe is connected to the first mounting mechanism of second coupling means.
17. A flexible coupling for joining a driving shaft to a driven shaft in a drive train apparatus of the type having a nominal axis of rotation, the flexible coupling comprising:
(a) first and second coupling means for attachment to the driving and the driven shafts, each coupling means including first and second mounting mechanisms located radially from the nominal axis of rotation;
(b) intermediate coupling means for providing an intermediate coupling between the first and second coupling means, the intermediate coupling means including first and second mounting mechanisms located radially from the nominal axis of rotation; and (c) a first flexible disc-like coupling element adapted to be operatively located in between the first and the intermediate coupling means and a second flexible disc-like coupling element adapted to be operatively located in between the intermediate and the second coupling means, each flexible disc-like coupling element comprising:
(i) a hub portion at least partially defining and at least partially surrounding a central aperture, the hub portion comprising a radial dimension as defined from the central aperture;
(ii) connector portion means for connecting a corresponding lobe to the hub portion;
(iii) a plurality of lobes including each of the corresponding lobes which are spaced from the hub portion, each lobe consisting of a pair of substantially arcuate shaped arms joined together adjacent its corresponding connector portion means, extending away from one another in substantially opposite directions, and terminating in free ends; and (iv) attachment means, proximate the free ends of the arms, for attaching said each flexible disc-like coupling element to the first and second coupling means, the attachment means being configured to connect the disc-like coupling element in a first and a second operational configuration, the first configuration consisting of connecting the ends of both arms of one lobe to one of the two coupling means and connecting the ends of both arms of another lobe to the other of the two coupling means, the second configuration consisting of connecting the end of one arm of a particular lobe to one of the two coupling means and connecting the end of the other arm of the particular lobe to the other of the two coupling means.
(a) first and second coupling means for attachment to the driving and the driven shafts, each coupling means including first and second mounting mechanisms located radially from the nominal axis of rotation;
(b) intermediate coupling means for providing an intermediate coupling between the first and second coupling means, the intermediate coupling means including first and second mounting mechanisms located radially from the nominal axis of rotation; and (c) a first flexible disc-like coupling element adapted to be operatively located in between the first and the intermediate coupling means and a second flexible disc-like coupling element adapted to be operatively located in between the intermediate and the second coupling means, each flexible disc-like coupling element comprising:
(i) a hub portion at least partially defining and at least partially surrounding a central aperture, the hub portion comprising a radial dimension as defined from the central aperture;
(ii) connector portion means for connecting a corresponding lobe to the hub portion;
(iii) a plurality of lobes including each of the corresponding lobes which are spaced from the hub portion, each lobe consisting of a pair of substantially arcuate shaped arms joined together adjacent its corresponding connector portion means, extending away from one another in substantially opposite directions, and terminating in free ends; and (iv) attachment means, proximate the free ends of the arms, for attaching said each flexible disc-like coupling element to the first and second coupling means, the attachment means being configured to connect the disc-like coupling element in a first and a second operational configuration, the first configuration consisting of connecting the ends of both arms of one lobe to one of the two coupling means and connecting the ends of both arms of another lobe to the other of the two coupling means, the second configuration consisting of connecting the end of one arm of a particular lobe to one of the two coupling means and connecting the end of the other arm of the particular lobe to the other of the two coupling means.
18. The flexible coupling of claims 17 wherein each flexible disc-like coupling element further comprises at least one lug portion connected to and extending away from the hub portion, each lug portion comprising attachment means for attaching said each flexible disc-like coupling element to other elements of the drive train apparatus.
19. The flexible coupling of claim 17 further comprising a plurality of flexible disc-like coupling elements which are assembled to form a disc pack having a closed-shaped hub portion and which are located between the first and second coupling means, each flexible disc-like coupling element overlying another flexible disc-like coupling element of the disc pack such that the attachment means of each flexible disc-like coupling element are substantially aligned with the attachment means of another flexible disc-like coupling element.
20. The flexible coupling of claim 17 further comprising a plurality of disc-like coupling elements which are assembled to form a disc pack having an open-shaped hub portion and which are located between the first and second coupling means each disc-like coupling element overlying another disc-like coupling element of the disc pack such that the attachment means of each disc-like coupling element are substantially aligned with the attachment means of another disc-like coupling element.
21. The flexible coupling of claim 17 connected in the first configuration wherein both arms of a first lobe are connected respectively to the first and second mounting mechanisms of the first coupling means, and both arms of a second lobe are connected respectively to the first and second mounting mechanisms of the second coupling means.
22. The flexible coupling of claim 17 connected in the second configuration wherein one arm of a particular lobe is connected to the first mounting mechanism of one coupling means, and the other arm of the particular lobe is connected to the first mounting mechanism of another coupling means.
23. The flexible coupling of claim 18 connected in a third operational configuration wherein both arms of one lobe of the first disc-like coupling element are connected respectively to the first and second mounting mechanisms of the first coupling means, the at least one lug of the first disc-like coupling element is connected to the first mounting mechanism of the intermediate coupling means, the at least one lug of the second disc-like coupling element is connected to the second mounting mechanism of the intermediate coupling means; and both arms of one lobe of the second disc-like coupling element are connected respectively to the first and second mounting mechanisms of the second coupling means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2027902 CA2027902C (en) | 1990-01-11 | 1990-01-11 | Flexible coupling for joining a driving member to a driven member |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2027902 CA2027902C (en) | 1990-01-11 | 1990-01-11 | Flexible coupling for joining a driving member to a driven member |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2027902A1 CA2027902A1 (en) | 1991-07-12 |
| CA2027902C true CA2027902C (en) | 2001-05-01 |
Family
ID=4146183
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2027902 Expired - Lifetime CA2027902C (en) | 1990-01-11 | 1990-01-11 | Flexible coupling for joining a driving member to a driven member |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2027902C (en) |
-
1990
- 1990-01-11 CA CA 2027902 patent/CA2027902C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2027902A1 (en) | 1991-07-12 |
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| Date | Code | Title | Description |
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| EEER | Examination request | ||
| MKEX | Expiry |