EP0116034A1 - Dispositif de transmission de mouvement - Google Patents

Dispositif de transmission de mouvement

Info

Publication number
EP0116034A1
EP0116034A1 EP19820902364 EP82902364A EP0116034A1 EP 0116034 A1 EP0116034 A1 EP 0116034A1 EP 19820902364 EP19820902364 EP 19820902364 EP 82902364 A EP82902364 A EP 82902364A EP 0116034 A1 EP0116034 A1 EP 0116034A1
Authority
EP
European Patent Office
Prior art keywords
elements
wheel
profiles
transmitting device
motion transmitting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19820902364
Other languages
German (de)
English (en)
Inventor
John Craven Carden
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GAUNTGLEN Ltd
Original Assignee
GAUNTGLEN Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by GAUNTGLEN Ltd filed Critical GAUNTGLEN Ltd
Publication of EP0116034A1 publication Critical patent/EP0116034A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H1/00—Toothed gearings for conveying rotary motion
    • F16H1/28—Toothed gearings for conveying rotary motion with gears having orbital motion
    • F16H1/32—Toothed gearings for conveying rotary motion with gears having orbital motion in which the central axis of the gearing lies inside the periphery of an orbital gear

Definitions

  • MOTION TRANSMITTING DEVICE This invention relates to motion transmitting devices of the kind known as quadrant drive devices.
  • Quadrant drive motion transmitting devices which may be used for speed changing, torque conversion and the like, are described for example in U.S. Patent Specifications Nos. 4,023,440 and 4,194,415 (U.K. Nos.1519588 and 1585961) and in U.K. Application No.8011061.
  • engagement is provided normally only by one tooth at a time.
  • meshing elements are employed which may remain in driving engagement with wheel means through a substantial fraction of a cycle; drive may be effective over nearly a quadrant of arc on the wheel means.
  • Such devices essentially comprise eccentric means, wheel means and independently movable meshing elements the movement of which is controlled by movement limiting means so that the ⁇ meshing elements move in and out of engagement with portions of the wheel means.
  • the meshing elements may comprise links with two or more teeth, these being links of a chain.
  • the present invention is directed to an improved form of quadrant drive motion transmitting device in which the meshing elements are independently movable and need not be linked in a chain but in which it is still possible to retain the high efficiency arising from pure rolling motion between relatively moving load-transmitting elements.
  • the present invention has particular advantages using a wheel with close-pitched teeth or a frictionally-driven wheel and hence enabling high torque or speed ratios to be obtained.
  • a motion transmitting device including eccentric means, wheel means, non-linked and non-rotatable independently movable elements adapted to engage said wheel means and movementlimiting means including a datum member with first profiles, second profiles in said independently movable elements and individual connector elements each engaging a first profile and a second profile to be held in captive dependency thereby wherein rotation of the eccentric means causes said movable elements sequentially to become engaged with a portion of the wheel means and subsequently to become disengaged therefrom, said independently movable elements being individually guided by said movement-limiting means within predetermined limits of orbital motion relative to said datum member such that a plurality of said independently movable elements are always simultaneously in engagement with and stationary relative to a respective portion or portions of the wheel means whilst drivingly engaged, said first and second profiles constraining the independently movable elements to move into engagement with the wheel means and to remain in engagement therewith over an arc of less than a semicircle and disengaging means constraining the independently movable elements to disengage from and to remain dis
  • the independently movable elements are not linked in a chain. These elements are made non-rotatable, that is to say, they are prevented from any substantial rotational movement or tilting with respect to the datum member about any axis through the element parallel to the axis of the wheel means. This ensures that the elements, when out of engagement, cannot tilt and foul the wheel means, and, when engaged, are not tilted by the torque reaction of the wheel means. As will be described later, there are a number of ways in which this non-rotatability can be achieved. Very conveniently, it is obtained by providing two of said individual connector elements for each of said independently movable elements.
  • Said independently movable elements may be arranged around the outside of the wheel means in what will be referred to as a male configuration or they may be inside the wheel means in what will be referred to as a female configuration.
  • disengaging means may be employed, for example, springs between adjacent ones of said independently movable elements.
  • any one of these three integers may be used as the input to the motion transmitting device and any other one may be used as the output.
  • the third integer may be a second input or a second output but, in general, is fixed.
  • a male configuration it is convenient to use the eccentric as the input and the wheel means as the output with the datum member fixed, assuming a speed reduction is required.
  • the input and output are interchanged if a speed step-up ratio is required.
  • a female configuration it is convenient to use the eccentric as the input (or output) and the datum member as the output (or input), the wheel means being fixed.
  • the meshing elements are further linked, for example by being formed as links of a chain as in the arrangements of the specifications referred to above, where the further linking serves to help control the movement of the links.
  • the independently movable elements conveniently are meshing elements having teeth adapted to mesh with teeth on said wheel means.
  • the independently movable elements and wheel means may be adapted for frictional engagement when the elements are moved into contact with the wheel means.
  • Each of the independently movable elements has to engage the wheel means for torque transmission but must be capable of being moved radially with respect J:o the wheel so that the element can be moved into and out of engagement with the wheel. When in engagement, there is no relative motion between the wheel means and the element.
  • the elements and wheel mean ? preferably have complementary mating surfaces to give a large rigid contact when in engagement.
  • the wheel means may be a toothed wheel with evenly spaced teeth. In a male configuration, these are outwardly directed teeth whereas, in a female configuration, they are inwardly directed teeth.
  • Each independently, movable element meshes with these teeth when in engagement with such a toothed wheel and i.s conveniently referred to as a meshing element.
  • Such a meshing element may extend around an arcuate portion of the wheel embracing several teeth on the wheel.
  • each meshing element is shaped so as to engage with all the teeth in the arc over which the element extends but, as will be apparent from the following description, the device would be operative even if the meshing element only had one tooth engaging the wheel in that arc. Multi tooth engagement is preferred to share the load.
  • the teeth on the meshing elements and wheel means are not gear teeth and do not transmit any load whilst in relative motion.
  • the teeth on the meshing elements are conveniently of inverted dovetail shape, facing radially inwardly of the wheel means and with the narrower end of the dovetail radially innermost and the wheel means has recesses complementary to the teeth on the meshing elements, these recesses being evenly spaced around the periphery of the wheel. If the meshing element has a plurality of teeth, these are positioned to face inwardly for a male configuration or outwardly for a female configuration in appropriate radial directions with respect to the centre of the wheel so that when one of the meshing elements is pressed against a circumference of the wheel, it forms a perfect fit around an arc of the wheel and becomes in effect part of the wheel.
  • the inverted dovetails serve to provide a perfect joint between the meshing elements and the wheel means in a similar manner to wooden joints made by machine tools where the dovetail is inverted (as distinct from hand-made dovetail joints where the dovetail has its larger end outermost to cause the joint to lock).
  • the inverted dovetails are used in the present case so that the meshing elements and wheel means may move in and out of engagement during each cycle.
  • the inverted doyetail joint provides full area contact between the adjoining flanks of adjacent dovetails, unlike meshing gear teeth, it becomes possible to make the dovetail pitches very fine yet retaining considerable strength in the joint.
  • This is in addition to the inherent advantage of a plurality of dovetails being meshed at any one time. It is thus possible to have very high ratios handling high torques with small unit size.
  • the meshing elements are under no load while engaging and disengaging from the wheel means and, because of the very small radius of gyration of the eccentric, 1 mm in the example described above, very high efficiencies are possible.
  • the meshing elements are maintained in engagement with the wheel means only in the radially implosive portions of the driving and reverse driving cycle.
  • the driving portion is within approximately an octant and the reverse driving portion, of generally similar arcuate extent, lies over an adjacent arc of approximately an octant.
  • the meshing elements are positioned by said movement-limiting means to be out of engagement with the wheel means.
  • a quadrant drive apparatus having teeth on meshing elements engaging a toothed wheel
  • the device forms a speed changing or torque conversion system as is described in the aforementioned specifications.
  • a very high ratio may be obtained. It is convenient, in describing the present invention, to consider a specific example.
  • the movement-limiting means may comprise a datum plate having 20 holes constituting first profiles, through which pass rollers, constituting the aforementioned connector elements, which rollers also each pass through a hole in a meshing element this hole constituting the aforementioned second profile.
  • the pitch of the teeth on the wheel means (and on the meshing elements) might be
  • the holes in the datum member would be disposed around the circumference of a circle with the pitch of the holes being 16 mm, plus an amount represented by the radially outward disposition of these holes from the arc on the meshing elements at which the 4 mm tooth pitch is measured.
  • This arc corresponds to the radius of the circle of the wheel means. It is desirable that the eccentric means effecting eccentric motion between the datum plate and the wheel means has a pitch of one quarter of the pitch of the teeth and thus the eccentricity would be 1 mm.
  • the side flanks of the meshing element are straight and form radii to the centre of the wheel means when drivingly engaged to have firm engagement with their neighbouring elements in the implosive portion of the power cycle and the reverse power cycle, that is to say when the meshing elements are in engage ment with the wheel.
  • the elements can then support one another as in the stones of a circular arch.
  • the radially inward forces acting on the elements in this implosive portion of the power cycle are very similar to the forces imposed by gravity on the stones of an arch. These inward forces hold the meshing elements in engagement with the wheel means.
  • the meshing elements When the meshing elements are out of engagement, they move radially outwardly and will separate from one another.
  • the disengagement of the meshing element is controlled by the aforementioned profiles which are engaged by the connector elements.
  • These connector elements conveniently are roller pins.
  • the profiles are conveniently holes which are suitably shaped . As is explained in U.S . 4 ,194 , 415 , these profiles are theoretically ovoid holes. The ovoid shape is required only however over part of the circumference of each hole. Since the radially inward portion of each hole on the datum is not being used Csince only the implosive portion of a power cycle is Being used! it is convenient to form this non-used portion of the hole in the shape of a semicircle .
  • the base locus line of the holes forming the first and second profiles is constructed for an eccentricity of 1 mm and for 4 mm pitch teeth, and also since the arrangement described above is a double ovoid configuration with profiles in the meshing elements and in the datum member, so that the base loci in each case are halved compared with a single ovoid configuration of U.S.4,023,440, and furthermore since the roller pin is the size required for a 16 mm chain loop, the base loci content of the ovoid hole becomes very small relative to the circular content of the hole caused by the comparatively large radius of the roller pin. This means that the hole is necessarily much closer to circular form.
  • a further advantage of this configuration is that, although the pitching of the roller pins or other connector elements is large compared with the pitch of the teeth on the wheel and meshing elements, because of the small eccentricity the radius of gyration is small. Thus the difference in the circumference of the roller pin and the holes is small which results in very low rolling speeds of the roller pins in their holes.
  • each profile may be larger than the connector element (usually a pin) which engages it, thereby giving a "double-ovoid” form of operation analagous in some respects to the double-ovoid construction of the aforementioned U.S.No.4,194,415.
  • each element has a tongue extending into a groove in the next adjacent element so as to limit tilting as the elements move apart.
  • Other movement limiting means may be used.
  • light compression springs may be located between the flanks of the meshing elements to ensure that they do not tilt and that all remain radially outwardly disposed away from the axis of the wheel means. Such springs also serve to ensure that the elements move apart in the disengaged portion of the cycle.
  • the invention includes within its scope a quadrant drive motion transmitting device having eccentric means, wheel means with portions shaped to engage with independently movable meshing elements and movement limiting means including a datum member, the eccentric means being arranged to cause the meshing elements sequentially to enter into and subsequently move out of engagement with portions of said wheel means, said meshing elements being individually guided by said movement limiting means through independent connector elements and wherein, of the three integers comprising the eccentric means, the wheel means, the datum member, one is connected to a rotational input, another is connected to a rotational output and a third is fixed characterised in that the wheel means comprises a wheel with (mn - 1) evenly spaced stations for engaging meshing elements and in that there are m meshing elements, each having an inwardly facing portion adapted to engage with the wheel over an arcuate extent of n stations on the wheel, where m is an integer equal to or greater than 8 (and preferably equal to or greater than 16), n is an integer equal to or greater than 2 (and preferably equal to or greater than
  • the movement-limiting means preferably includes, for each meshing element, a connector pin adapted to roll around a closed profile on the datum member and a closed profile on the meshing element.
  • the profiles may be shaped so that each meshing element is held out of engagement from the wheel means over an arc greater than 180o by suitably shaping the radially inward portions of the profiles on the datum member and the radially outward portions of the profiles on the meshing elements.
  • each meshing element has n teeth or is shaped to engage with n teeth on the wheel. It is desirable but not necessary for all stations on the wheel in the power octant and reverse power octant to be filled. However the device will operate even if some stations are not occupied.
  • Figure 1 is a front elevation showing diagrammatically a datum plate, wheel means, some of the meshing elements and the associated connector elements of a motion transmitting device forming one embodiment of the invention
  • Figures 2, 3 and 4 are each a front elevation, similar to part of Figure 1 but showing respectively three modified constructions of meshing elements;
  • Figure 5 is a front elevation illustrating two meshing elements of another construction
  • Figure 6 is a side view partly in section, of part of the device of Figure 5;
  • Figure 7 is a front elevation, similar to part of Figure 1 but showing a modified construction;
  • Figure 8 is a cross-section, along the line 8-8 of Figure 9, of a two-stage device according to the invention, in which the second stage is a planocentric device;
  • Figure 9 is a cross-section along the line 9-9 of Figure 8;
  • Figure 10 is a diagram illustrating a simple mechanical construction for the experimental determination of an ovoid profile
  • Figure 11 shows typical traces drawn by the construction of Figure 10
  • Figure 12 illustrates a graphical determination of an ovoid profile for accommodating a cylindrical pin of a predetermined diameter
  • Figure 13 illustrates a profile such as might be used in an embodiment of the present invention
  • Figures 14 and 15 illustrate another embodiment of the invention
  • Figure 16 is a front elevation illustrating a modification of the construction of Figure 14;
  • Figure 17 is a further front elevation illustrating a modification of the construction of Figure 1;
  • Figure 18 is a view similar to Figure 15 but illustrating a modification
  • Figures 19 and 20 illustrate respectively further modifications of a datum plate and of connector elements .
  • FIG. 1 there is shown diagrammatically a, motion transmitting device having a datum member 1 with an input shaft 2 and eccentric 3.
  • the centres of the input shaft and of the eccentric are indicated at 4 and 5 respectively.
  • the eccentricity is the distance ⁇ .
  • a wheel 6 is free to rotate about the eccentric, that is to say on the centre 5.
  • This wheel in this particular embodiment "has 79 teeth 7.
  • the spaces between the teeth are of inverted dovetail form, that is to say they have straight sloping sides which diverge in a radially outward direction symmetrically about the radius through the centre of the space.
  • the device has 20 keystone-shaped meshing elements 8 of which only some are shown in the drawings. The shape of these meshing elements is such that their flanking surfaces abut one another when the meshing elements are in contact with the wheel means forming a circular arc about the centre of the wheel.
  • Each meshing element has four radially inwardly extending teeth 9, the shape of these teeth Being complementary to the gaps between the teeth on the wheel means.
  • the datum plate 1 has 40 holes 10 constituting the aforementioned first profiles, these holes being evenly spaced on a circle around the centre of rotation of the input shaft.
  • Each meshing element has two holes 11, each constituting one of the aforementioned second profiles.
  • the inverted dovetail-shaped spaces between the teeth on the wheel 6 lie on a pitch circle 13 which is centred on the centre 5 of rotation of the wheel.
  • the holes 10 in the datum plate have design centres on a pitch circle 15 which is centred on the centre of rotation 4 of the input shaft 2.
  • the pins 12 are roller pins which roll around the peripheries of the profiles of the holes 10 and 11 and serve to control the position of the meshing elements.
  • the meshing elements are constrained over part of the arc to lie out of engagement with the wheel.
  • the pins 12, under gravity rest on the lower periphery of the holes 10 in the datum member 1 and the elements 8, under gravity, rest on the pins 12.
  • the shaping of the holes 10 and 11 positively hold the elements 8 in or out of engagement with the wheel 6 as necessary.
  • the meshing elements 8 in the upper part of Figure 1 are in the implosive portion of the power cycle and the reverse power cycle.
  • This portion comprises approximately an octant (on the upper left side of the figure for the directions of rotation shown by the arrows A and B) forming the driving cycle and another adjacent octant (towards the upper right of the figure) constituting the reverse driving cycle.
  • the elements shown at 18 in the lower part of the figure are in the disengaged portion of the cycle.
  • the profiles are shaped so that the meshing elements are positively moved out of engagement from the wheel over the disengaged portion of the cycle, the lower half in the condition shown in Figure 1. Because they are positively disengaged in this way, there is no need to link the elements 8 into a continuous loop, as in the arrangements of the aforementioned U.S.Specifications Nos.4,023,440 and 4,194,415 (U.K. Nos. 1519588 and 1585961) and European Published Application No. 0037387 (U.K.Application No.8011061), where endless chain constructions are employed. This considerably simplifies the construction and assembly of the device.
  • the elements 8, being non- linked, are independently movable.
  • the meshing elements are made non-rotatable, that is to say means are provided for preventing any element 8 from substantial rotational movement about an axis through the element parallel to the axis of the wheel.
  • substantial rotation of elements 8 is prevented by the use of two pins 12 engaging separate holes 11 in each meshing element.
  • These pins 12 in conjunction with the profiles in the datum plate thus serve not only to guide and hold the meshing elements in engagement with the wheel during part of the cycle and to disengage the meshing elements and hold them disengaged during another part of the cycle but also to prevent any substantial rotation of the meshing elements.
  • the two pins 12 for each element 8 need not necessarily be located on a common circle about the centre of the wheel in order to prevent the element 8 from tilting. In principle, the two pins may be located at any two points spaced apart on the element.
  • the meshing elements 8 furthermore cannot tilt when in the engaged position because they abut one another over their flanking faces.
  • the elements 8 form a rigid arch with the whole group of elements over this arc acting as one unit transmitting torque between the datum member and the wheel.
  • the elements 8 cannot tilt, as is ensured by the provision for example of two pins 12 for each element, it is not essential that, in abutting one another, the elements 8 should have area contact.
  • the elements might be shaped as shown at 18 in Figure 2, having contact at 19 when they are in engagement with the wheel 6. More generally however, provided the elements cannot tilt, it is not essential that they should abut.
  • Figure 3 is a view, similar to part of Figure 1, showing non-abutting elements 8a which are generally similar in other respects to those of Figure 1, being prevented from tilting by the provision of two pins.
  • each element 8 has only one hole 11 and pin 12 and each element 8 has a tongue 22 on one "side flank of the element extending into a corresponding groove 23 on the next adjacent element.
  • the tongues and grooves have sufficient length that the tongues do not completely disengage from the grooves even in the fully relaxed portions of the quadrant drive cycle, that is to say corresponding to the lower part of Figure 1.
  • the tongues and grooves serve to prevent any tilting of the meshing elements in the disengaged part of the cycle.
  • Figures 5 and 6 illustrate the provision of compression springs 20 between the elements 8, these being located in holes 21 in the lateral flanks of the elements and serving to keep these elements apart in the disengaged portion of the cycle. These springs 20 moreover assist in preventing any tilting of the meshing elements. The springs 20 also cause disengagement of these elements from the wheel.
  • Figure 6 is a side view of the device taken along a section plane extending arcuately through the connector pins 12. As seen in Figure 5, the datum member 1 lies on both sides of the wheel 6. The pins 12 extend into both parts of the datum member and pass through the elements 8. The springs 20 are seen in Figure 4 extending between the locating holes 21 in adjacent elements 8.
  • the individual elements 8 or 8a are multi-tooth elements extending, when in the engaged position, around an arc of the wheel 6 embracing several teeth.
  • the movement-limiting means constituted by pins 12 and holes 10, 11 cause the elements to effect orbital movements giving a relative movement between the element and wheel of one tooth per cycle. This can be achieved even if the elements 8 are not multi-tooth elements.
  • Figure 7 illustrates the extreme condition where the elements 8b each have only one tooth 24.
  • the elements 8b are shown spaced apart in the engaged part of the cycle and each is prevented from tilting or rotation relative to the datum plate 1 by two pins 25 which engage in ovoid or circular holes 26 in the element 8b and in ovoid or circular holes 27 in the datum plate 1.
  • the holes in each element are spaced radially, instead of circumferentially as in Figure 1.
  • This construction is particularly advantageous with motion transmitting devices with lower torque ratios than that of Figure 1, for example with twenty elements engaging nineteen teeth 28 on the wheel. It will be noted that such a device, unlike the quadrant drive devices of U.S.Patent Specifications Nos.
  • any one of these three components may be used as the input, any other one as the output and the third may be fixed.
  • the speed and torque ratios will depend on the choice of the input and output. Referring to Figure 1, if the output is taken from a rotating and gyrating element such as the wheel 6, it will often be desirable to provide means for bringing the rotary output back to an axis co-linear with or concentric with the axis of the input shaft. Known forms of "back-to-centre" couplings may be used for this purpose.
  • the eccentricity can be very small and it may often be possible to use a very simple "back-to-centre" coupling such as a flexible shaft.
  • a preferred form of coupling, having a high efficiency will be described with reference to Figures 8 and 9.
  • FIGs 8 and 9 a motion transmitting device in which the torque converter is essentially similar to that illustrated in Figure 1, as previously described in considerable detail, together with a double planocentric device which brings back to centre the eccentrically rotating output of the first stage.
  • the first stage includes the input shaft 2 which is formed with an eccentric portion 3 about which bearingly rotates a toothed wheel 6.
  • Datum plates 40 and 42 are fixedly supported on the frame 41 of the device.
  • the wheel 6 and the datum plates 40 and 42 are similar to those previously described in connection with Figure 1, and they interengage through the meshing elements 8 and pins 12 as also previously described.
  • the wheel 6 is further fixedly attached to cylindrical member 47 to which, in turn, are fixedly attached two first planocentric discs 36, which are therefore also eccentrically rotating.
  • the first planocentric discs 36 and the second planocentric disc 33 have all the same number of holes 37, which have a circular profile.
  • the holes 37 of first planocentric discs 36 and of the second planocentric disc 33 are coupled to one another by means of roller pins 34 which are thus captive within their respective sets of holes.
  • the centres of all holes 37 on first planocentric discs 36 are equidistantly arranged about axis O'-O', while the centres of all holes 37 on second planocentric disc 33 are equidistantly arranged about axis O-O, the distance between these two axes being the eccentricity ⁇ .
  • Diameter of hole 37 diameter of pin 34 + ⁇ .
  • a counterweight 46 conveniently counterbalances the forces caused by the eccentrically rotating masses. This counterweight would be positioned at other locations along the eccentric 3, the most obvious being between the frame and the wheel 6, however the location shown in Figure 8 is a better choice because it is located between the gyrating masses, which makes possible almost perfect dynamic balancing.
  • this double planocentric arrangement provides not simply a constant velocity, back-to-centre, coupling means, but a very superior one, in fact, vastly superior to a conventional planocentric arrangement (having a single plate with holes) in that since this novel arrangement makes possible a pure rolling motion of the captive rollers 34 within the holes 37, it reduces friction to a (theoretical) value of zero.
  • the holes 10 and 11 of Figure 1 in the datum plate 40,42 and meshing elements 8 respectively have theoretically to be of ovoid form in order to get pure rolling motion of the roller pins 12 around these holes during the operation of the device and also to obtain multitooth engagement.
  • the shape of the ovoids depends on the eccentricity but this shape has to be imposed on a larger shape required by the pin diameter. It will be shown later that, in certain embodiments of this invention, it is practical to depart from this theoretical shape and have circular holes.
  • Figure 10 is a "draughting machine" on which the shapes of such "profiles" will be determined and their parameters explored.
  • disc 49 is the
  • reaction element on which the desired profiles will be traced. These profiles will have “design centres” on pitch circle C p (having its centre at O) .
  • Pitch circle C s is smaller than pitch circle C p and the two circles are displaced from one another by the eccentricity ⁇ .
  • the centres O and O' are "fixed to earth", i.e. they are axes (fixed and stationary) about which C p
  • C s may freely rotate, separately and Independently from one another.
  • C p and C s to be discs, or pulleys, freely rotatable about 0 and O' respectively.
  • a belt is placed around C p and another belt around C s both belts encircling a common idler disc I, the spindle of which is also "fixed to earth", and a stylus is attached at point A on the periphery of C s (point A being at the greatest overlap between C p and C s above axis X'-X).
  • point A being at the greatest overlap between C p and C s above axis X'-X.
  • curves include a number of ovoid shapes, such number depending solely on the ratio of the two radii of C p and C s while the size of the ovoid (the ovoid area shown cross-hatched) depends on the eccentricity ⁇ .
  • the angle ⁇ p (see Figure 11) depends on the ratio of the two radii of circles
  • the shape of the "profile" we are seeking is an ovoid locus.
  • the stylus (connecting meshing element, or pin, having a diameter equal to zero) on C s will engage such an ovoid on C p during a selected (design choice) fraction of a full rotation (360°). 3. If such a stylus on C s is "withdrawn” during the remaining portion of the above-noted selected fraction of a full rotation (i.e. during the angle equivalent to the b-b trace), this withdrawal could in practice correspond to a disengagement cycle, during which the stylus, i.e. the meshing connecting element, could "jump over" (i.e. advance by) one, or more, teeth, thereby obtaining considerable speed reduction.
  • disengagement must occur before 90°, i.e.
  • the eccentricity may be made much less than and hence the base locus of the ovoid is small, as shown at the right hand side of Figure 11.
  • the base locus ovoidal content of the ovoid hole becomes smaller in relation to the circular content created by the roller pin which has to be superimposed upon the base locus, but has not been correspondingly reduced in diameter since, in the example given, one pin works for four tooth pitches.
  • the pin diameter is quite large, being suitable for a 16 mm pitch chain loop but the eccentricity is only 1 mm.
  • the base loci for the ovoid holes is halved compared with a single ovoid arrangement. Because of these factors the base loci content of the ovoid hole in the construction of the present invention becomes very small relative to the circular content of the hole caused by the comparatively large radius of the roller pin.
  • the exact shape of the hole is an ovoid departing only very, very slightly from a true circular hole.
  • chain line curve 50 shows, in the upper half of the figure, an ovoid profile determined as described above from a base locus 51 representing the radially implosive portion of the power cycle which is to be used.
  • Curve 54 represents the radially explosive portion which is not used and is substituted by semicircular profile 55.
  • the working profile 50 is completed around the bottom part by a semicircular arc 52 since the shape of this part of the profile is not being used in the power cycle, but for disengagement purposes as previously described.
  • a semicircle 53 is shown as a full line around the upper part of the figure. This shows how small is the deviation from a circle and thus why a circular hole can be used.
  • a further advantage arising from the small difference in the circumference of the roller pins compared with that of the holes in the datum plates and the holes in the meshing elements is that this greatly reduces the Hertzian stress load (that is to say stress loads due to repetitive reversal of load pressure on the surface) on the surfaces of the walls of the holes and on the surfaces of the roller pins. This in turn reduces the chances of brinelling on these surfaces.
  • FIGs 14 and 15 are diagrams explaining such a device using a V-pulley and V-shaped frictional elements.
  • Figure 14 is a sectional elevation and Figure 15 is a transverse section of a V-pulley 60 freely rotatable on a needle-bearing (shown only in Figure 15 for clarity) on an eccentric 61 carried on an input shaft 62.
  • a plurality of wedge-shaped segments 63 are arranged around the pulley.
  • Each segment has an ovoid or circular hole 64 through which passes a pin 65 of cylindrical section, the pin being in rolling engagement with the profile of the ovoid or circular hole 64 and also with the profiles of ovoid or circular holes 66 in a pair of datum plates 67, one on each side of the pulley.
  • These datum plates are rigidly secured together to form the capturing plate assembly of a double ovoid quadrant drive in which the segments 63 move cyclically into and out of engagement with the pulley 60.
  • the segments in Figures 14 and 15 each have a single hole 64 and pin 65 and each has a tongue 68 engaging a groove 69 to prevent relative tilting, as has been described with reference to Figure 4. Furthermore the segments abut one another when they are in engagement with the pulley. Other arrangements may be employed to prevent tilting, for example by using two pins per segment as in the construction of Figure 1.
  • roller pins 65 provide positive outward pull for positive disengagement of the segments in the appropriate part of the cycle.
  • the choice of the number of segments, the size of the roller pins and the radius of the pulley can be made as a function of the torque to be transmitted and may be independent of the ratio required. With very high ratios, the eccentricity becomes small and the back-to-centre coupling can be of simple construction. Because of the small eccentricity, circular profiles can usefully be employed in this application for the reasons already given.
  • a "double ovoid" arrangement has been employed having ovoids in the meshing elements or segments and in the datum means. Because of the small eccentricity which is used with high ratio devices of the present invention, it may, in many cases, be preferred to use single ovoid or circular profile arrangements.
  • the pins such as pins 12 of Figure 1 or the pins 65 of Figures 14 and 15, might be journalled in either the datum means or the meshing elements and roll around the periphery of an ovoid or circular hole in the other of these elements.
  • the meshing elements comprise a plurality of segments. It is not essential that all the segments in any one embodiment should be identical.
  • any one of the meshing elements 8 of Figure 1 might be replaced by two or more adjacent elements, each with its pin and ovoid or circular hole or holes.
  • Friction elements such as have been described with reference to Figures 14 and 15 need not necessarily abut one another although abutting elements, forming a rigid arch around the sector where they engage the wheel are generally preferred.
  • Figure 16 illustrates a modification of the construction of Figure 14 but employing non-abutting elements 80 which frictionally engage the wheel 60,
  • each element has two apertures 81 receiving separate pins 82 to prevent the elements 80 from tilting.
  • Other means such as those previously described, may be employed to prevent tilting of the elements 80 with respect to the datum plate 67.
  • the capturing plate or corresponding element will still be referred to as the datum member.
  • this capturing plate or datum member is used as the output.
  • the movable elements corresponding to the elements 8 of Figure 1 are moved into and out of engagement with a surrounding female member which is referred to as the stator and which corresponds with the wheel means of Figure 1 in that it engages the elements but would usually be fixed.
  • an input shaft 2 drives an eccentric 3 rotatably carrying a capturing plate 90 in which there are a plurality of ovoid or circular apertures 10 in which are pins 12. These pins engage circular or ovoid holes 11 in movable elements 92.
  • the elements 92 have outwardly directed teeth 93, conveniently of inverted dovetail form, which mesh with corresponding inwardly directed teeth 94 on a fixed plate or stator 95.
  • the elements 92 when in mesh with the stator 95 , are sufficiently far apart that they can be withdrawn inwardly to a disengaged position. Orbital movement of the elements 93 is effected, by rotation of the eccentric 3 relative to the capturing plate 90, causing the latter to gyrate and so effecting the required orbital movement of the elements 93.
  • the ovoid or circular holes have profiles as previously described to give positive engagement and disengagement in the appropriate parts of the cycle.
  • the arrangement thus constitutes a "one-tooth differential" driving the capturing plate 90 with a speed reduction ratio of 1:80.
  • two pins 12 are used for each element 92 to prevent tilting but one pin per element may be used if tilting is prevented by other means.
  • a friction drive arrangement may also be constructed with a female configuration as shown in Figure 18. This may conveniently be compared with Figure 15 showing a corresponding male construction.
  • an input shaft 62 drives an eccentric 61 on which is rotatably mounted a capturing plate assembly 100 incorporating two parallel plates 101 lying one on each side of the movable elements 102.
  • Pins 103 extend each through an ovoid or circular hole 104 in each of the plates 101 and through an ovoid or circular hole 105 in the elements 102.
  • the elements 102 have side surfaces shaped to engage conical surfaces 106 in the stator.
  • the elements must, when engaged, be spaced circumferentially to permit of them moving radially inwardly when so guided in their individual orbital paths by the pins 103 and holes 104,105.
  • the magnitude of the orbital movement of the elements 102 determines the amount of movement relative to the member (in this case the stator) with which these elements engage. This orbital movement will be small compared with the arcuate spacing of the elements and hence high speed ratios are readily possible.
  • Female constructions may have back-to-centre couplings as in male arrangements.
  • each hole has a profile with two portions, one portion being shaped for moving the elements into engagement and holding them there and the second portion moving the elements out of engagement and holding them out of engagement, that is to say preventing them from moving into engagement in this part of the cycle.
  • the second portions of the profiles provided they ensure proper movement out of engagement, are not critical and, as previously explained are conveniently circular arcs. It is possible to use “open-loop" profiles (as distinct from “closed-loop” profiles) so long as alternative disengaging means (such as springs) is provided in place of said second portions which have been removed to form the open loop.
  • the profiles may be circular arcs.
  • Figure 19 illustrates an arrangement similar to Figure 1 but with open-loop profiles 110 on meshing elements 111 but closed-loop profiles 112 on a capturing plate (i.e. datum member) 113.
  • Connector pins 114 engage with and are retained by the profiles 110, 112.
  • Figure 20 illustrates an arrangement similar to Figure 1 but with open-loop profiles 120 on a datum plate 121 and closed-loop profiles 122 on meshing elements 123.
  • Connector elements 124 engage with and are retained by the profiles 120, 122.
  • Such open-loop profiles may facilitate manufacture and assembly of the device.
  • Figures 19 and 20 operate, as described with reference to Figure 1, to control the orbital movement of the connector elements with respect to the wheel 6 and also, since there are two pins for each element, to prevent tilting of the elements. in both these configurations springs 125 provide the disengaging means.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Retarders (AREA)

Abstract

Un dispositif de transmission de mouvement du type à entraînement à cadran possède une roue (6), de préférence dentée, une pluralité d'éléments mobiles indépendants (8) s'engageant l'un après l'autre avec la roue, un organe de repérage (1) et un excentrique (3) effectuant un mouvement relatif excentrique entre la roue (6) et l'organe de repérage (1). Des ergots connecteurs (12) mobiles dans des trous ovoïdaux ou circulaires (11, 12) dans la roue (6) et l'organe de repérage (1) guident les éléments mobiles (8) afin que ceux-ci s'engagent avec la roue (6) ou se dégagent de celle-ci. Les éléments mobiles (8) ne sont pas liés, comme dans une chaîne, mais des moyens tels que l'utilisation de deux ergots (12) par élément (8) sont prévus pour empêcher tout basculement des éléments (8) ou toute rotation de ces éléments par rapport à l'organe ou aux organes de repérage. D'autres moyens permettant d'empêcher le basculement sont décrits. Cette construction en particulier facilite l'obtention de vitesse ou de rapport de couple élevés avec un rendement élevé.
EP19820902364 1982-08-05 1982-08-05 Dispositif de transmission de mouvement Withdrawn EP0116034A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/GB1982/000245 WO1984000589A1 (fr) 1982-08-05 1982-08-05 Dispositif de transmission de mouvement

Publications (1)

Publication Number Publication Date
EP0116034A1 true EP0116034A1 (fr) 1984-08-22

Family

ID=10527471

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19820902364 Withdrawn EP0116034A1 (fr) 1982-08-05 1982-08-05 Dispositif de transmission de mouvement

Country Status (2)

Country Link
EP (1) EP0116034A1 (fr)
WO (1) WO1984000589A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007019607A1 (de) * 2007-04-02 2008-10-16 Wittenstein Ag Koaxialgetriebe, insbesondere Hohlwellengetriebe für die industrielle Antriebstechnik

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1339301A (fr) * 1962-11-16 1963-10-04 Appareil de transmission de vitesses de rotation
US3726158A (en) * 1971-02-04 1973-04-10 H Brown Speed-reducing coupling
BE770716A (fr) * 1971-07-30 1971-12-01 Soudure Autogene Elect Reducteur de vitesse sans friction et a grands rapports de reduction.
GB1519588A (en) * 1974-08-02 1978-08-02 Precision Mechanical Dev Motion transmiting devices
US4194415A (en) * 1978-05-08 1980-03-25 Dimitracopoulos Panayotis C Quadrant drive
DK541978A (da) * 1978-11-30 1980-05-31 Roe Ka Teknik Aps Gear
EP0014784B1 (fr) * 1979-02-12 1983-02-16 Precision Mechanical Developments Limited Dispositif de transmission de mouvement
IE51023B1 (en) * 1980-04-02 1986-09-03 Precision Mechanical Dev Motion transmitting devices having a toothed wheel and independently movable meshing elements
US4429595A (en) * 1980-10-23 1984-02-07 Emerson Electric Co. Motion transmitting device
IE820231L (en) * 1981-02-09 1982-08-09 Prec Mechanical Developments L Quadrant drive motion transmitting device - i.e. having¹tooth engagement of more than one tooth

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8400589A1 *

Also Published As

Publication number Publication date
WO1984000589A1 (fr) 1984-02-16

Similar Documents

Publication Publication Date Title
US4449425A (en) Motion transmitting devices
EP0037287B1 (fr) Dispositif pour transmettre un mouvement et roues dentées y étant employées
EP0472683B1 (fr) Systeme d'engrenages
US3435705A (en) Harmonic drive power hinge pins
US4567790A (en) Motion transmitting system
US7086304B2 (en) Roller cam assembly
IE42926B1 (en) Improvements relating to motion transmitting devices
GB1567331A (en) Planetary gesring
JPS6211223B2 (fr)
US4846008A (en) Traction roller transmission
EP0080805A2 (fr) Système de transmission de mouvement
US4995279A (en) Transmission systems
US7028572B2 (en) Pitch transfer gear and transmissions
EP0116034A1 (fr) Dispositif de transmission de mouvement
GB2092706A (en) Epicyclic gearing
EP3177841B1 (fr) Accouplement de couple de un à un
CN212028444U (zh) 一种链带无级变径装置
GB2117474A (en) Improvements in or relating to gear boxes
US6212967B1 (en) Variable gear assembly and method
US6066061A (en) Continuously variable gear transmission
EP0114561B1 (fr) Système transmetteur de mouvement
EP0014784B1 (fr) Dispositif de transmission de mouvement
EP1426659B1 (fr) Transducteur differentiel de vitesse "reducteur - roulement"
US7241245B2 (en) Gear-bearing differential speed transducer
GB1585969A (en) Motion transmitting devices

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): NL SE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 19840907

RIN1 Information on inventor provided before grant (corrected)

Inventor name: CARDEN, JOHN, CRAVEN