This invention relates to an angular velocity profile generator which is adjustable to provide output angular velocity profiles to suit various machine drive applications and to a transmission machine including the angular velocity profile generator.
Many infinitely variable transmission (IVT) machines have over the years been proposed and developed in attempts to produce, from a constant input velocity, an acceptable linear continuously variable output angular velocity and torque.
The basic approach to these machines has been initially to apply a single input angular velocity to a number of parallel stages of the machines which by means of angular velocity generators such as cams, slotted plates, linkages, off-centred sun gears, non-circular gears, orbital devices, universal joints and so on produced pulsed or cycled angular velocities (angular acceleration and deceleration cycles) in each of the stages which are appropriately phased to the input angular velocity. The pulsed or cycled angular velocities from the machine stages are then used to drive selective extraction devices, such as overrunning or sprag clutches and/or differentials which extract the maximum portions of the driven cycles of the parallel stages to provide modulated angular velocity outputs. These outputs are then recombined in an output stage of the machine to provide the output angular velocity of the machine. Examples of these machines are disclosed in the specifications of the following publications: WO82/02233, WO89/11604, WO90/01648, WO91/18225, WO94/11652, WO02/14715, FR916850A, U.S. Pat. No. 1,916,283A, U.S. Pat. No. 3,114,273, BE444789A and FR1071870A
Common problems which are typically associated with IVT machines of the prior art are that:
they are capable of transmitting power in only one direction of rotation, which cannot be reversed,
their cyclic angular velocity generating devices generate, in each parallel stage of the machine, a full cycle of a periodic motion on each revolution of their input shafts with their single drive direction overrunning clutch extraction devices being capable of clipping only the single maximum velocity peak from each cycle. The consequence of this is that the angular velocity output arrangements of the machines, such as planetary gear systems, are largely incapable of fully modulating the coarsely rippled output of the extraction devices to an acceptable purely or nearly so theoretically constant linear output velocity. The majority of the cyclic angular velocity generating devices which are employed in the IVT machines, and which include oscillating components such as the slotted plates, linkages which drive or are driven by off-centre gears, cams and the like suffer from balancing and other vibration problems which are principally caused mainly by shock loads generated by the direction changing mechanisms. The above are complex machines not suitable for practical implementation with the necessary level of reliability.
An angular velocity profile generator according to the invention comprises;
a first shaft,
a second shaft,
a universal joint in which the first and second shafts are joined to each other by pivot pins which lie on two axes which are fixed relatively to and intersect each other and the axes of the first and second shafts at a static point in the joint with the radially outer ends of the pivot pins on each of the pivot pin axes, in use, being rotatable in first and second circular paths about the static point,
a first control arrangement for moving one of the shafts relatively to the other to vary the angular relationship between them at the universal joint,
means in the universal joint which enables the path of rotation of the first universal joint pivot pin axis to be varied, in use, relatively to the path of rotation of the second pivot pin axis about the static point in the universal joint, and
a second control arrangement, external to the universal joint, which is connected to the first pivot pin path varying means and is activated by the first control arrangement to cause, in use, as the first control arrangement is moved, the angular relationship between the first and second shafts and the first pivot pin path varying means to be adjusted in a predetermined relationship to achieve an output angular velocity profile to suit a specific application of the angular velocity profile generator.
The profile generator conveniently includes spaced formations which are fixed to the second shaft and with which the pivot pins of the second pivot pin axis are pivotally engaged, a support frame including spaced first and second frame members in each of which one of the profile generator shafts is journaled for rotation and the first control arrangement is means for moving one of the frame members relatively to the other to vary the angular relationship of the two shafts in a common plane.
The first pivot pin path varying means may include a housing which is pivotally mounted in the support frame for pivotal movement on an axis which is normal to and intersects, at the static point, the common plane in which the profile generator shafts are relatively movable to each other, a bore through the housing with the axis of the bore intersecting the static point and a circular path guide in the bore in which the ends of the pivot pins on the first universal joint pivot axis are engaged for rotation.
The pivot pin circular path guide may be a ring which is trapped in the housing bore for rotation only, relatively to the housing, about the housing axis with the ends of the pivot pins on the first universal joint pivot axis pivotally engaged in diametrically opposite formations on the ring.
In a preferred form of the profile generator of the invention the pivot pins on the first pivot pin axis are engaged with the first shaft by an arrangement which enables the pivot pins on the first pivot pin axis to oscillate during rotation of the first and second shafts, in use, in a path of rotation about the static point in the universal joint with the path of rotation of the pivot pins being fixed and angled relatively to the first shaft axis at a predetermined angle relatively to a line which is normal to the first shaft axis at the static point in the universal joint. The second control arrangement preferably includes a profiled ramp formation in the support frame and a ramp follower which is connected to the housing and is adapted to move over and follow the profile of the ramp formation to cause the path of rotation of the first pivot pin axis to be angularly varied relatively to that of the second pivot pin axis with the profile of the ramp formation and the position of the ramp follower on it, in use, determining the profile of the cyclic angular velocity output of the profile generator.
In one form of the invention the first pivot pin axis pivot pin engaging arrangement includes a second ring which is located in the first ring on a common centre at the static point with diametrically opposite pivot pins of the second pivot pin axis projecting from its outer surface to be pivotally located in the spaced formations on the second shaft, and the first pivot pin axis pivot pin first shaft connecting arrangement is a pivot shaft which is fixed to the first shaft with its axis passing through the static point in the universal joint and is angled at a predetermined angle relatively to a line, which passes through the static point, which is normal to the axis of the first shaft and a rotor on the pivot shaft which carries the pivot pins on the first pivot pin axis which is normal to the pivot shaft axis and passes through the static point in the universal joint.
In a second form of the invention the universal joint pivot pins are continuous pins which are fixed to each other in the form of a crucifix and the first universal joint axis pivot pin engaging arrangement includes two spaced arms which are fixed to the first shaft, an elongated slot in each of the arms with the longitudinal centres of the slots being situated in a common plane which includes the static point in the universal joint which is angled at a predetermined angle relatively to a line which passes through the static point and which is normal to the first shaft axis with the pivot pins on the first universal joint pivot axis passing through the slots with their ends pivotally located in apertures in the first ring.
Further according to the invention there is provided an infinitely variable transmission machine which comprises;
an angular velocity input member,
an angular velocity output member,
a plurality of angular velocity transmission stages which each include a cyclic angular velocity generator,
an input divider arrangement with which the angular velocity input member is engaged for applying the input angular velocity, in use, to the cyclic angular velocity generator in each of the transmission stages in a fixed ratio of rotation relatively to each other,
an extraction device in each transmission stage which is driven by a cyclic angular velocity generating device in that stage to extract an absolute maximum angular velocity pulse section from the output of the angular velocity generating device during each revolution of the machine input member,
an output collector arrangement which is adapted to sum the extracted outputs of each of the extraction devices in each of the transmission stages and to apply the summed extraction device outputs to the machine output member,
preferably the cyclic angular velocity generating device in each transmission stage is the preferred form of the angular velocity profile generator with the first shaft of each of the profile generators being connected to the angular velocity input member of the machine through the input divider and their second shafts each engaged with an extraction device.
The preferred form of the profile generator may be the first form of the angular velocity profile generator of the invention.
Alternatively, the preferred form of the profile generator may, however, be the second form of the angular velocity profile generator of the invention.
The path of rotation of the pivot pins on the first universal joint pivot axis in each of the profile generators of the transmission machine may be angularly variable relatively to and include the second universal joint pivot axis and the second control arrangement may be adjusted to provide an angular velocity output profile which includes a section of linear angular velocity.
Each revolution of the machine input member may cause each profile generator to produce at the input to the extraction device of each transmission stage a single, substantially sinusoidal, angular velocity which includes the section of linear angular velocity with the number of transmission stages of the machine being dependent on the number of linear velocity section durations which are required together to provide a continuous linear velocity at the output member for each revolution of the machine input member.
Preferably each transmission stage includes two of the profile generators which are connected to each other in series with the second shaft of the first profile generator being connected to the first shaft of the second profile generator to provide an intermediate shaft between the two profile generators. Conveniently, one of the shafts of the intermediate shaft is linearly splined and the other includes a splined bore in which the splined portion of the splined shaft is telescopically slidable.
The transmission stages of the machine may be located in a common support frame with a first frame member carrying the input divider arrangement with which the first shafts of the first profile generators in each transmission stage are rotatably engaged and a second frame member which carries the extraction devices with which the second shafts of the second profile generators are engaged with the frame members being movable relatively to each other. The second frame member may be the first control arrangement of each of the profile generators in each transmission stage and is movable relatively to the first frame member.
In one form of the machine the transmission stages may be arranged in a side by side relationship in the common support frame with the first shafts of the first profile generators being journaled for rotation in the first frame member with the input divider comprising an input gear on each of the profile generator first shafts with the gears being meshed together in a 1:1 ratio of rotation with the angular position of each of the first profile generator shafts being rotatably phased from each other by the angular duration of the linear velocity output sections of the extraction devices. The second frame member may be the first control arrangement of the profile generators in each transmission stage and is vertically movable on a guide arrangement which is fixed to the common support frame with the extraction devices being fixed to the second frame member with the second shafts of each of the second profile generators passing through the second frame member to be engaged with an extraction device and the machine includes, means for moving the second support frame between a first position in which all of the shafts of the profile generators in a transmission stage are aligned and a second position on the guide arrangement in which the axis of the second shaft of the second profile generator of each transmission stage is parallel to and displaced from the axis of the first shaft of the first profile generator with all of the profile generator shafts in each transmission stage, in all positions of movement of the second frame member, being situated in a common plane.
The first pivot pin path varying means housing of each first profile generator in each transmission stage may include an arm which is fixed to and extends from the housing and operates in the plane including the axes of all of the shafts of the profile generator and carries on it the first profile generator ramp follower which follows the profile of a ramp formation which is attached to the second frame member as the second frame member is moved between its two positions of operation.
The first pivot pin path varying means housing of each second profile generator in each transmission stage may include an arm which extends from the housing and operates in a plane including all of the axes of the shafts of both profile generators with the ramp follower on it following the profile of a ramp formation which is fixed to the support frame as the second frame member is moved between its two positions of operation.
The angular velocity output collector comprises an output gear which is attached to and index rotated once by a transmission stage extraction device during each revolution of the machine input member with the output gears being meshed with one another so that sequentially phased indexed rotation of the gears by the extraction devices will together provide a continuously linear output velocity at the machine output member for each single rotation of the machine input member.
The extraction devices may each be a one-way clutch such as a sprag clutch or the like. Preferably, the output gear of each transmission stage is an externally toothed outer race of the one-way clutch.
The extraction devices may, however, each include a first clutch plate, a second clutch plate which is fixed to the machine output gear which it index rotates and an actuator which is engaged with the second shaft of the second profile generator in the transmission stage which is connected to the extraction device for moving the clutch plates on the common axis between a first position in which they are disengaged from each other to a second position in which they are engaged with one another to index drive the second clutch plate and so the transmission stage output gear. The clutch plates are conveniently rings of dog clutch teeth with the second clutch ring being fixed to a side of the output gear, which is continuously rotated, in use, in the machine output collector, with the first ring being movable towards and away from the second ring by the actuator against and with the bias of a biasing spring between the clutch plates.
Each extracting device actuator may include a synchronisation arrangement which, in use, is slidably located on and continuously rotated by the second profile generator second shaft and which on movement by the actuator of the first clutch, ring towards its second position of movement synchronously aligns the dog clutch teeth of the two clutch rings, prior to engagement, for perfect mesh of the dog teeth of the independently rotating clutch plate rings. The actuator of the extraction device of each transmission stage may include a cam arrangement which includes fixed and rotatable lobed annular cam members which surround and are free of the second shaft of the second profile generator, a drive ring for rotating the rotatable cam members with lobes on the fixed cam member acting on lobes on the rotatable cam members to cause, in use, the first clutch ring to be moved by the rotatable cam members from its first to its second position of movement for a fractional period of rotation of the second shaft of the second profile generator of each transmission stage.
The drive rings of the extraction device in each of the transmission stages are meshed together for concomitant rotation and the machine includes a drive arrangement for driving the coupled drive rings directly from the machine input divider.
The embodiment of the transmission machine wherein the extraction devices are one-way clutches could include an arrangement for reversing the direction of rotation of the output shaft of the machine including a driven gear which is engaged with and driven by the machine output collector gears, a ratio varying planetary gear arrangement, a suitable transmission arrangement which is driven by the drive gear to drive a drive gear which in turn drives the first sun gear of the planetary system with the second sun gear being driven by an extended machine input shaft while the cage of the planetary system is connected to the machine output member. The same arrangement could be employed to extend the ratio range of the machine.
An embodiment of the invention, as adjusted for producing a linear output angular velocity, is now described by way of example only with reference to the drawings in which:
b) is, for clarity, an enlargement of the profile generators of
The IVT machine of the invention is shown in
Each of the four angular velocity transmission stages 16 includes coupled profile generators 22 and 24 of the invention and an angular velocity extraction device 26 the outputs of which are fed to the output shaft 12 through the output collector 18.
The transmission stage 16 of
The angular velocity profile generators 22 and 24 in the transmission stage are identical and are shown in
The swivel arrangement 49 is fixed to an end of the drive shaft 46 and includes a housing 60 which is cup-shaped and carries an axially located pivot pin 62 which projects upwardly from the centre of the base of the cup with its axis 64 at an angle λs relatively to an axis 66 which is normal to the axis 47 of rotation of the drive shaft 46, a rotor 68 which is rotatable about the pivot pin 62 and includes diametrically opposite trunnion pins 70. The sides of the swivel housing 60 are cut away to provide space for free oscillatory movement of the trunnion pins 70 about the pivot pin 62 axis 64. The housing includes a cap 72 for trapping the rotor 68 in the housing.
The gimbal ring 50 includes diametrically opposite trunnion holes 74, the ring 52 includes diametrically opposite trunnions 76 and trunnion holes 78 with the trunnion and hole axes being at an angle δ to each other. The gimbal yoke 54 includes trunnion holes 80. The adjuster ring 58 carries trunnions 82 with their axis 83 being normal to and intersecting a plane which passes centrally through the length of a control lever 84 which is made integral with the ring 58. The ring 58 additionally includes an inner diametrical recess in which the gimbal ring 50 is located to be rotatable about its axis but is held by the recess against other movement relatively to the angle adjuster ring 58.
The profile generator is shown assembled in the
In
With the profile generators 22 and 24 of
The regulation of θ1 and λ1 for the profile generator 22 is accomplished by the control arm 84 of the profile generator 22 moving its shaft 88 in the slot 38 of the sliding frame with the curvature of the slot 38 being such as to ensure the correct values of θ1 and λ1 for the profile generator 22 as the sliding frame 32 is moved upwardly or downwardly on the guide rails 30 of the transmission stage framework.
The regulation of θ2 and λ2 of the profile generator 24 is achieved by its control arm 84 moving the shaft 90 in the slot 44 in the frame member 42. The curvature of the slot 44 is such as to ensure the correct values of θ2 and λ2 for the profile generator 24 as the sliding frame is moved upwardly or downwardly on the guide rails 30. The angle β, not shown in the drawings, between the axis 81 of trunnion holes 80 of gimbal yoke 54 of the connecting shaft 92 and the plane in which λs of the input shaft 46, of the profile generator 24, is measured, may be 0°.
The various components of the two profile generators 22 and 24 in
In
The derivation of the linear velocity of the angular velocity curves of a single angular velocity profile generator 22 or 24 of
If the adjuster ring 58 is rotated about its pivot axis 83 such that its front face is normal to the output shaft 56 axis 57 (
When non-zero values of θ and λ exist the values may be chosen so that the combined effect will include a constant angular velocity section (c) (see
From the above it is seen that this invention relies on the fact that for certain combinations of the variables for a single profile generator or n profile generators in series, the variables (θ1,λ1,λs1,θ2,λ2,λs2,β1,δ1 . . . θn−1,λn-1, λs(n-1),θn,λn,λs(n),βn-1,δn-1) can be chosen (by suitable configuration of the slots 38 and 44 and positioning of the angle adjuster rings 58) to produce a perfect constant angular velocity section. It is to be noted that
In the graphs of
The output unit 94 and extraction device 26 of each transmission stage 16, in this embodiment of the invention, are combined in a single unit, as shown in
The output unit 94, as shown in
The radial positioning devices 124 in the output gear 120 are circumferentially spaced on the wall of the recess in the gear to provide slots 126 between them.
The gear 120 additionally includes a rearwardly facing integral ring 130 of dog clutch teeth.
The axial displacer 96 is essentially a disc which carries on its forward face an annular ring 132, see
The rim portions 136 of the axial displacer 96 are engageable in the slots 126 in the output gear 120 and are dimensioned to permit limited rotation of the displacer relatively to the output gear. One edge of each of the positioning devices 124 in the output gear 120 and the axial displacer 96 rim portions 136 are suitably profiled to engage the displacer springs 118 between them in the assembled unit. The circumferential dimensions of the slots 126 and the displacer rim portions 136 in fact limited the degree of spring 118 loaded relative rotation of the output gear and the axial displacer to less than the width of one tooth on either of the toothed rings.
The synchroniser unit 98 includes an annular ring plate 138 which has an outer diameter equal to that of the toothed ring 134, as shown in
The radially extending serrated teeth on the toothed rings 122, 132, 134 and 140 are, as shown in
A bendix-like helically splined sleeve 142 is integral with and projects from the rear face of the synchroniser unit 98. The sleeve bore is linearly splined to receive the splines on the output shaft 56 extension piece to enable the synchroniser unit 98 to be slidable on the shaft in its axial direction, in use. The outer surface of the sleeve 142 carries helical male splines which are slidably engaged with complementally helixed female splines in a bore in a boss 114 on the rear of the inner coupling hub 104 and a rearwardly facing pressure ring 145.
In the assembly of the synchronisation unit 98 and the coupling hub 104, the spring 100 is located over the spline sleeve 142, as shown in
The forwardly directed skirt of the coupling hub 104 is castellated by circumferentially spaced slots 148 which, in the assembled output unit 94, are slidably engaged with rectangular keying formations 150, see
The outer coupling hub 106 carries a ring of dog clutch teeth 151 which are complementally shaped to and engageable with those on the ring 130 of the output gear 120.
The four hub springs 116, as shown in
The inner cam unit 110 carries diametrically opposite peripheral driver formations 160 which are slidably engaged in slots 162 in the bore of the outer cam unit 108. The rear face of the cam unit 110 carries two cam lobes 164 which, in use, ride on the front face of the cam profile unit 112 which includes four cam lobes 166, 168, 170 and 171, as seen in
In the assembled extraction device the cam lobes 166 and 168 bear against the rear face of the outer cam unit 108 to interact with its cam lobes 154, in use, and the lobes 170 and 171 bear against the rear face of the cam unit 110 to interact with its lobes 164.
A ring bearing 153 is in the assembled unit located on the cam profile unit 112 up against a rear flange on the unit, as shown in
The entire extraction device 26 and the output unit 94, as shown in
During operation of the transmission stage 16 the cam driver 114 gear 172 and so the cam units 108 and 110 which are engaged with it are rotated by the
The arrangement of the outer cam unit 108 lobes 154 and the outer cam profiles 166 and 168 of the cam profile unit 112 is such that when operated the outer cam unit 108 is forced away from cam profile unit 112 for a duration of 45° of a single revolution which results in a 90° duration of rotation on the input shaft 10 because of the above mentioned 2:1 ratio of rotation on the cam driver 114 between them. This action will therefore occur twice for each revolution of cam driver 114 or once for each revolution of the input shaft 10.
The arrangement of the inner cam lobes 170 and 171 of the cam profile unit 112 and the inner cam profiles 164 of the inner cam unit 110 is such that when operated the inner cam unit 110 is forced away from cam profile unit 112 for a duration greater than 45° which results in a greater than 90° duration on the input shaft 10 again because of the above mentioned 2:1 ratio. This action will occur twice for each revolution of cam driver 114 or once for each revolution of the input shaft 10.
As the cam driver 114 is rotated by the synchronising drive arrangement 20, the inner cam lobes 170 and 171 first come into contact with the inner cam unit lobes 164 on the cam profile unit 112 and ride onto the lobes 164 to cause the inner cam unit 110 to move forwardly against the pressure ring 145 of the inner coupling hub 104 to force the inner coupling hub 104 together with the synchronisation unit 98 forward toward the output gear 120 against the bias of the second coil spring 102 until the serrated teeth of the toothed rings 140 of the synchroniser unit and rear toothed ring 134 of the axial displacer 96 engage with each other.
Should the engagement of the serrated teeth on the toothed rings 140 and 134 result in a complete mesh the dog clutch teeth 130 on the output gear 120 and the teeth 151 on the outer coupling hub 106 will be synchronised and with further rotation of the cam driver 114 the outer cam unit lobes 154 on the outer cam unit 108 will come into contact with the outer cam lobes 168 and 166 on the cam profile unit 112 and ride onto the lobes to bring the forward smooth face of the outer cam unit 108 into pressure bearing contact with the pressure ring 155 of the outer coupling unit to force the coupling hub 106 and its ring of dog clutch teeth 151 forwardly into full mesh with dog clutch teeth 130 on the output gear 120 and so to cause the output gear 120 to rotate for the 45° duration of the cam dwell time while holding the four hub springs 116 compressed.
If, however, the engagement of the teeth of the toothed rings 140 and 134 result in an incomplete mesh, i.e. the sloping ramps of the teeth are engaged and not their parallel radial saw tooth driving faces, the forward motion of the synchronisation unit 98 will tend to be arrested and the dog clutch teeth 130 and 151 will not be synchronised in engaging alignment. The unrelenting forward cam induced force will override the biasing force of compression spring 100 and cause the inner coupling hub 104 to be moved forwardly and simultaneously to be twisted in rotation on the helically splined sleeve 142 of the synchronisation unit 98.
The angular displacement of this twisted motion is related to the magnitude of the incomplete mesh of the teeth of the toothed rings 140 and 134 and is sufficient to bring the dog clutch teeth 130 and 151 into synchronised register for full mating on further rotation of the cam driver 114. This will occur when the outer cam lobes 154 come into contact with the outer cam lobes 168 and 166 on the cam profile unit 112 and ride onto the lobes while forcing the outer coupling hub 106 and its dog clutch teeth 151 forward into full mesh with the dog clutch teeth 130 on the output gear 120 to drive the rotating output gear only for the duration of the 45° cam dwell time while holding the four hub springs 116 compressed.
Because of the time lag between the operation of the inner cam unit 110 and the outer cam unit 108 a situation might arise where, during this time lag, the teeth of the toothed rings 140 and 134 might become fully engaged and tend to drive one another. When this situation arises the tooth ramps of the synchronisation plate 132 and the tooth ramps of the synchronisation plate 122 will ride on each other to compress the four displacer springs 118 to keep the dog clutch teeth 151 and 130 synchronised and ready for smooth meshing on the action of the cams 154 of the outer cam unit 108 at the end of the time lag.
Thus far in the specification the operation of only one angular velocity stage 16 has been described.
From
The drive synchronisation arrangement 20 is shown in
The input divider gears 48, as are the cam driver gears 172 and the output collector 18 gears 120, coupled together in each gear set in a ratio of 1:1. The machine output shaft 12 is attached to a cage which is fixed to an output gear 120. The transmission machine's input and output shafts 10 and 12 respectively rotate in a common direction.
The gears 48 of the input divider are, as indicated by the lines on the ends of the input shafts which they drive, meshed at 90° with respect to each other whereas the cam driver gears 172 of the extraction devices 26 are meshed at 45°.
The amplitude of the transmission stage 16 output angular velocities and so the output range of the machine is varied, as mentioned above, by moving the ganged slide frames 32 upwardly and downwardly on the guide rails 30. In practice, the composite frame 32 may be movably controlled by a conventional servo motor leadscrew arrangement, not shown.
Additionally as the output shaft 12 of the machine is, in use, moving relatively to the framework of the machine the output shaft 12 will need to be coupled through a suitable coupling such as a universal joint arrangement, similar to the synchronisation drive arrangement 176, to a static remotely supported output shaft.
In use, using as an example the angular settings of
The input/output ratio R of the machine which is defined as
depends on the vertical height of the sliding frame 32 which determines the operating angle φ and with the correct values of θ1, λ1, θ2 and λ2 determined by the guiding slots 38 and 44 respectively together with the fixed values of λs=45°, β=0° and δ=90°, produces a constant ripple free output angular velocity (d) at the machine output shaft 12, as illustrated in
The above serves only as an example and is not limited to the above values for θ1, λ1, θ2, λ2, λs, φ, δ1, δ2 and β. Any combination of these values may be used to obtain a selected output angular velocity profile which may not necessarily, in other applications, be limited to a constant output angular velocity.
To vary the ratio range of the IVT machine of the invention, which is described above the machine of the invention with a ratio K that may vary from 1:1 to 1:1.4, as shown in
With Y=1, a typical equation governing the system in
Gout=0.5·X·Gin (1−K·C)
From the above equation it can be seen that the neutral point, where the IVT output is zero, is reached when K·C=1. By calculating the scaling factors C and X for a specific variable gearbox with ratio K, the desired ranges (forward and reverse) for the IVT can be set. For example if C=0.83 and K may vary from 1 to 1.4 the following is true:
X can be any fixed gear ratio while Gin may be any angular velocity input.
The IVT machine described with reference to
The IVT machine illustrated in
The simpler IVT machine of
Example of Ratio Range Extension of the
The machine of
The range variation arrangement of the
The drive arrangement 20 is driven by a gear 194 which is coupled in a 1:1 ratio to the meshed output collector gears 120 and drives, through the drive arrangement 20 a synchronisation gear 178. The gear 178, drives an idler gear 196 and a drive gear 198 of the planetary arrangement 192. Thus gear 194, 178, 196 and 198 represents scaling factor C in
The planetary gear arrangement 192 is shown in
In this example of the range extension method of the invention the number of teeth on the various gears are as follows:
In this example it is assumed that a constant input angular velocity of 1000 rpm is applied to the input shaft 10 of the machine in the positive direction of the arrow in
where
Solving for Vel 200 in equation A results in the following:
1:1 Variable Position
With the ratio between the input shaft 10 and the output gears 120 being 1:1 gear 198 and thus also gear 212 will be rotating at:
Gear 206, being connected via shaft 204 and gears 48 to the input shaft 10, will rotate at 1000 rpm. Using equation B the output angular velocity Vel 200 and so at the output shaft 202 is calculated as:
1:1.4 Variable Position
With the ratio between the input shaft 10 and the output gears 120 being 1:1.4 the gear 198 and thus also the gear 212 will be rotating at:
Gear 212, being connected via shaft 204 and gears 48 to the machine input shaft 10, will rotate at 1000 rpm. Using equation B the output angular velocity Vel 200 and so at the output shaft 202 is calculated as:
Thus the variation in ratio between the input shaft 10 and output shaft 202 is calculated as
Thus the range of the IVT have been extended from 1:1.4 to 1:2.33 by using above method incorporating a suitable planetary system.
Direction Changing Example
If the gear 206 contained 12 teeth and the gear 212 13 teeth then the e value of the planetary system becomes as follows with the use of equation A:
Solving for Vel 200 in equation A results in the following:
With all of the other gears remaining unchanged the following is true for different ratios of the variable unit:
1:1 Variable Position
With the ratio between the input shaft 10 and the output gears 120 being 1:1 the gear 198 and thus also the gear 212 will be rotating at:
Gear 206 being connected via shaft 204 and gears 48 to the input shaft will rotate at 1000 rpm. Using equation D the output angular velocity Vel 200 and so at the output shaft 202 is calculated as:
1:1.4 Variable Position
With the ratio between the machine input shaft 10 and the output gears 120 being 1:1.4 gear 198 and thus also the gear 212 will be rotating at:
Gear 212, being connected via shaft 204 and gears 48 to the input shaft 10, will rotate at 1000 rpm. Using equation D the output angular velocity Vel 200 and so at the output shaft 202 is calculated as:
It can thus be seen that the output range of the machine is now 46.66 rpm to −126.66 rpm and thus includes two ranges in different directions with a neutral point, where the cage 200 is stationary and locked. The angular velocity of gear 212 at this point can be calculated by setting equation D equal to zero with Vel 200=1000 rpm and solving for Vel 212 as follows:
The embodiment of the IVT machine of the invention which is illustrated in
The machine of
The ramped cams on the cam plates 222 and 228 corresponds in function to that of the slots 44 and 38 of the angular velocity profile generators of
The angle θ and λ adjuster rings 58 of the angular velocity profile generators 22 and 24 of this embodiment of the invention are controlled to compensate for operational rotation of the input divider 14 by spring biased cam followers 232 which ride on the cams 38 and 44 to suitably vary the plane of operation of the angle adjuster rings 58 and so the gimbal rings 50 which they carry.
The extraction device 26 cam driver gears 172 are, in this embodiment of the invention, driven by a continuous toothed drive belt 234 (not shown in
A gear 238 on the input shaft 10 is meshed with and drives the four gears 48 of the input divider 14 and a gear 240 which is attached to a tubular output shaft 12 is engaged with and driven by the output collector 18 gears 120.
The invention is not limited to the precise details as herein described. For example,
The slots 248 are not restricted to being located in a plane which includes the line 249 and instead of being linear, as shown in
In a further embodiment of the profile generator, which is related to that of
The applications of the angular velocity profile generator of the invention are not, as mentioned above, limited to the use in IVT machines which produce only constant linear output angular velocity profile sections but may find other applications requiring specified velocity profiles which do not necessarily include constant angular velocity sections. The following is an example explaining, with reference to
The graphs of
In another example the two angular velocity profile generators 22 and 24 of
Additionally in the case of the
In yet a further example the two angular velocity profile generators of the
Obviously a single angular profile generator may be used in the above applications in place of the two in series but it will limit the angular velocity profile variability and require the input and output shafts to be operated at an angle to each other.
A Mathematical Model of the
The following, together with
The profile generator components and centreline reference numbers have been omitted from
The following are, as seen in
The plane of great circle LKx intersects the input shaft 46 axis 47 and is also perpendicular to the plane in which λs is measured. The input shaft 46 angle, αout, is measured between the planes of great circles LKk and HI.
Great circle HE represents the path followed by the gimbal yoke 54 centre line B Bp (the plane of great circle HE is thus normal to the output shaft 56 axis 57) and the great circle FE represents the path followed by the swivel rotor 68 trunnion 70 centre line A Ap. Great circle FE thus represents the plane in which the adjuster ring 58 operates while rotating (for the adjustment of θ and λ) around the trunnions 82 axis 83 line between points E and Ep. The plane of great circle AJ presents the rotation of the input shaft 46 and thus rotates around the input shaft 46 axis 47 while intersecting with the rotor 68 trunnion pins 70 axis line A Ap. The plane of the great circle IE is normal to the input shaft 46 axis 47 and thus intersects the stationery adjuster ring 58 trunnions 82 axis 83 swivel points E and Ep. Great circle HI lies in the plane created by the input shaft 46 axis 47 and output shaft 56 axis 57. The plane of great circle AKs is normal to the swivel arrangement 49 pivot pin 62 axis 64 or line C S (See
The following derives the input shaft 46 angle, αout, as a function of the output shaft 56 angle α while assuming δ=90°: (See
If point A on the rotor 68 trunnion pins 70 axis is initially at point E then the yoke axis 81 of the output shaft 56 at point Bp will lag this point by 90° (δ=90°), and is shown as point F. The reason for this being the 90° (δ=90°) angle between the axis 79 of ring 52 trunnion holes 78 and the axis 75 of the ring 52 trunnions 76. As point B on the yoke 54 swivel axis 81 of the output shaft 56 moves from point E to B through an angle of α, point A on the rotor 68 trunnion pins 70 axis moves from F to A through an angle β. Locate a point D on great circle FE in such a way that angle DCE is equal to β. Thus angle ACD is a right angle, as constructed. Also angle ACB is a right angle because of the 90° (δ=90°) angle between the axis 79 of ring 52 trunnion holes 78 and the axis 75 of the trunnions 76. Consequently spherical angles ABD and ADB will be right angles. This in turn implies that spherical angle EDB is a right spherical angle. For right spherical angles the following is true:
cos(θ)=tan(β)·cot(α)
λ is measured from the normal of the input shaft 46 axis 47 thus the angle between great circles IE and FE illustrates the plane in which the adjuster ring 58 operates. Similarly θ is measured between the plane in which the adjuster ring 58 operates and the normal to the output shaft 56 axis 57 thus the θ angle between great circles FE and HE. The operating angle, φ, the angle between the input shaft 46 axis 47 and output shaft 56 axis 57, is equal to the sum of λ and θ.
λs illustrates the angle between the swivel pivot pin 62 axis line CS (
Thus the following relations exist:
From ΔEDB
tan(β)=cos(θ)·tan(α)
From ΔAEJ
From ΔAKxJ
From ΔEAK
The input shaft 46 angle is presented by αout. (See
Solving for αout by using the above equations with the mathematical software package MathCad (or similar software package for example MatLab, Mathematica) results in the following input shaft 46 angle function from which it may be determined:
The above equation presents the angular position of the input shaft 46, αout, of a single angular velocity profile generator 22 or 24 joint where:
The above equation can be differentiated with respect to α by use of a mathematical software package such as MathCad, MatLab or Mathematica to obtain the angular velocity function of the input shaft 46. Alternatively above equation can be numerically differentiated by incremental plot of above equation to obtain the input shaft angular velocity profile. This can easily be done on any spreadsheet such as Microsoft Excell or Lotus.
Theoretical Explanation of Output Velocity Profile
If the output shaft 56, in the case of
It is further noted that the plane of operation of the adjuster ring 58 may be any plane and thus not necessarily one that only pivots around axis 83 as is modelled in the mathematical derivation of the profile generator.
Number | Date | Country | Kind |
---|---|---|---|
2002-0066 | Jan 2002 | ZA | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/ZA02/00137 | 9/11/2002 | WO | 00 | 9/4/2003 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO03/056212 | 7/10/2003 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
1516070 | Amedee-Mannheim | Nov 1924 | A |
1916283 | Pressler | Jul 1933 | A |
2379454 | Nowka | Jul 1945 | A |
20040089085 | Naude | May 2004 | A1 |
20050097974 | Espinosa | May 2005 | A1 |
Number | Date | Country |
---|---|---|
750 690 | Aug 1933 | FR |
916 850 | Dec 1946 | FR |
WO 0214715 | Feb 2002 | WO |
Number | Date | Country | |
---|---|---|---|
20040089085 A1 | May 2004 | US |