FR2490766A1 - Variable inertial flywheel with centrifugal clutches - having masses mounted on torsion bars of different rigidity to engage successive units to increase inertia as speed increases - Google Patents

Abstract

The flywheel is coupled to the output shaft of a motor and stabilises its speed by absorbing overspeed energy and returning the energy when the speed falls. Multiple units are used with masses mounted so they act as centrifugal clutches to engage the next unit at different speeds, so increasing the flywheel inertia as speed increases. The flywheel is mounted on a hollow shaft coaxial with the motor shaft, and is coupled to it by a clutch. The first unit is fixed to the hollow shaft and carries a mass mounted on a torsion bar. As the speed rises the mass moves outwards and engages the drum of the next unit, which has the torsion bar mounted mass assembly coupled to the hollow shaft through a free wheel mechanism. Successive units are similarly coupled and control of the torsion bar characteristics allow successive units to be automatically engaged at successively higher speeds.

Description

 The present invention relates to inertial rotary devices, of the energy recovery type, intended to be coupled at will to a motor shaft so as to store energy during accelerations and to restore it during decelerations in order to regulate the speed of 11 shaft.

 In this field, there are currently known numerous devices comprising at least one flywheel which is associated with a drive shaft, either directly or via a centrifugal clutch device operating for a speed predetermined tree. There are also known devices comprising several different flywheels which are successively coupled, electromechanically or electromagnetically, depending on the speed detected on the shaft. However, these devices are generally fragile and complicated and require constant and delicate maintenance.

 The invention aims to remedy these drawbacks by providing a rotary inertia device which is simple, reliable and easy to maintain.

 According to the invention, a rotary inertia device, of the energy recovery type, comprising a first shaft connecting a motor and a user device, further comprises a second shaft coupled to the first via a clutch and a series of flywheels arranged coaxially and side by side on the second shaft and comprising a first flywheel integral with said second shaft and comprising a first centrifugal clutch device intended to cooperate, for a first critical speed, with at least one flywheel bell-type intermediate wheel surrounding the first flywheel, this intermediate flywheel being mounted on said second shaft by means of a freewheel device and comprising a second centrifugal clutch device intended to cooperate, for a second critical speed, with a last flywheel of the bell type surrounding the intermediate flywheel, the latter flywheel being mounted on said second shaft by means of a freewheel device .

 In other words, the rotary device according to the invention comprises a series of intermediate flywheels associated with the first and last flywheels, all these flywheels each comprising a centrifugal clutch device except the last flywheel, each being of the bell and device type. freewheel except the first steering wheel, and cooperating two by two for critical speeds going from the first to the last steering wheel.

According to other peculiarities
each centrifugal clutch device comprises identical peripheral weights, each of which is pivotally mounted on a cheek of the flywheel considered, is provided with an elastic return member, which may be a torsion bar, and has a cylindrical surface of complementary shape that of an internal wall of the bell of the next steering wheel of the series
- For each steering wheel, either the weights have an increasing mass, or the return members of the weights have an increasing elastic power, or the pivot axes of the weights are arranged according to a circumference whose radius decreases, depending the row of the steering wheel considered, from the first to the penultimate steering wheel in the series
- The first and second shafts are coaxial, the second shaft being tubular and mounted for free rotation around the first.

Other characteristics and advantages of the present invention will emerge more clearly from the description which follows, given with reference to the appended drawings in which
FIG. 1 represents a schematic longitudinal view of an embodiment of the inertial rotary device according to the invention, with partial sections and cutaway showing certain elements of the centrifugal clutch devices and of the freewheel devices, and
2 shows a schematic cross-sectional view along the broken line II-II of Figure 1, with sections and partial cutaway of certain clutch devices according to different planes.

 In these drawings, the same references designate the same elements.

 Referring to FIGS. 1 and 2, an inertial rotary device, of the energy recovery type, essentially comprises a first shaft 1, a second shaft 2 coupled at will to the first shaft by means of a conventional clutch 3, and a series of flywheels mounted on the second shaft 2. the first shaft 1 is generally a motor shaft connecting a motor and a device for use, for example the transmission shaft of a road vehicle or the shaft of a wind turbine. the second shaft 2 can be arranged in any way with respect to the first shaft 1 but, according to a possible embodiment of the invention, the two shafts are coaxial, the second shaft 2 being tubular and mounted for free rotation around the first, for example on ball or needle bearings.

 According to the invention, the flywheels are arranged coaxially and side by side on the second shaft 2, so as to be able to rotate with respect to each other on the latter.

They comprise a first flywheel 4, at least one intermediate flywheel or a series of intermediate flywheels of which only four are represented and designated by 5, 6, 7 and 8, and a last flywheel 9. All these flywheels, except the last flywheel 9, each comprise a centrifugal clutch device which is designated as a whole by 10 and all these flywheels, except the first flywheel 4, are each of the bell type surrounding the previous flywheel or, more precisely, the mobile parts of the centrifugal clutch 10 which is associated with the previous flywheel in the series. Consequently, all the flywheels can cooperate two by two via the centrifugal clutch device 10 and the bell 11 which are respectively associated with them.

 According to a preferred embodiment, each centrifugal clutch device 10 comprises identical peripheral weights 12 each of which is pivotally mounted on a cheek 13 of the flywheel considered and is provided with an elastic return member. Preferably, each counterweight 12 has a cylindrical surface 14 having a shape complementary to that of an internal wall 15 of the bell 11 of the steering wheel according to the series. In the simplest case, the bell II is produced without a solution of continuity with the cheek 13 and is in the form of a cylindrical crown whose internal wall 15 is parallel to the second shaft 2 and to the pivot axis 16 of each of the weights 12.

 The elastic return member which is associated with each counterweight 12 may be a simple spring, spiral or not, or else a torsion bar 17, one end 18 of which is secured to the counterweight 12 and the other end of which is secured to the cheek of the steering wheel considered. According to a variant limiting the bending forces of the torsion bar 17, its end 18 secured to the counterweight 12 is extended by a shaft end 20 freely rotating in a housing formed in the cheek 13, while its other end 19 is secured to a cheek piece 21 forming part of the steering wheel and making it possible to obtain better balancing of each steering wheel during its rotation.

 According to the above, when the first flywheel 4 or one of the intermediate flywheels 5 to 8, that is to say each of the flywheels provided with a centrifugal clutch device 10, is rotated until that its speed reaches and then exceeds a critical clutch speed for which the centrifugal force acting on each counterweight 12 outweighs the restoring force exerted by the associated torsion bar 17, it follows that said counterweight pivots around its axis 16 until its cylindrical surface 14 comes to bear against the internal wall 15 of the bell it associated with the following flywheel of the series, the counterweight thus engaged occupying the position which is shown in phantom for two opposite counterweights in the figures 1 and 2.

it is obvious that when the speed of the flywheel considered decreases to be less than the aforementioned critical speed, the restoring force exerted by each torsion bar 17 outweighs the centrifugal force acting on the associated counterweight 12 and the latter resumes its disengaged position, which is shown in solid lines in FIGS. 1 and 2, by releasing the bell 11 from the following steering wheel in the series.

 it should be noted that the clutch and declutching operation as described so far can be carried out for one or the other direction of rotation of each of the flywheels provided with a centrifugal clutch device. However, given that the center of gravity of each counterweight 12 is necessarily offset relative to its pivot axis of pi 16, it is generally preferable to use such an offset forward rather than rearward in order to obtain a clutch and disengagement in principle drier and more precise.

For example, in the case shown in FIG. 2, it is preferable for the flywheels to be flown counterclockwise rather than clockwise, so that most of the body and the center of gravity of each counterweight 12 are offset forwardly relative to the pivot axis 16 of said counterweight.

 Furthermore, according to another feature of the invention, all the flywheels are mounted on the second shaft 2 by means of a freewheel device 22, with the exception of the first flywheel 4, which is made integral with said second shaft 2, for example by means of a key 23. In principle, the freewheel devices 22 are all identical and are mounted so as to operate identically for the same direction of relative rotation relative to the second shaft 2.

 These freewheeling devices can be locking devices with wedging of a known type and each comprise, for example, one or more sets of identical asymmetrical shims 24 uniformly distributed at a determined inclination in a cavity concentric with the second shaft 2 and connected together by a spring (not shown) tending to straighten them. In the simplest case, the cavity is formed in a hub 25 connecting the cheek 23 and the counter cheek 21 of each flywheel and it is in the form of an annular groove whose bottom wall 26 is concentric with the outer surface of the second shaft 2.

 it is obvious that in all the freewheel devices 22 respectively associated with each of the intermediate flywheels 5 to 8 and the last flywheel 9, the shims 24 are all inclined on the same side, that is to say that each shim has substantially the same inclination relative to a respective reference diametral plane. it follows that all of the flywheels 5 to 9 have the same blocked direction of rotation and the same opposite direction of rotation which is not locked or free relative to the second shaft 2. Taking into account the inclination which is shown by way of example for the wedges 24 visible in FIG. 2, a rotary movement of the second shaft 2 taking place clockwise relative to the flywheels 5 to 9 determines a blocking of the related freewheel devices 22 and a drive of said flywheels, while a movement the relative rotation of the second shaft 2 taking place counterclockwise does not determine any drive of the flywheels. Conversely, a relative rotary movement of one of the flywheels 5 to 9 taking place counterclockwise determines a blocking of the freewheel device associated and entralanement of the second shaft 2, while a relative rotary movement of said flywheel taking place clockwise does not cause the second shaft 2.

 When using the inertial rotary device as described so far, when the first and second shafts 1 and 2 are coupled via the clutch 3, the second shaft 2 is normally driven in the non-direction blocked vis-à-vis the freewheel devices 22, that is to say counterclockwise in the case shown in FIG. 2.

 Under these conditions, the first flywheel 4, which is integral with the second shaft 2, is driven directly by the latter in a counterclockwise direction. When the speed of the dry shaft 2 and of the first flywheel 4 reaches then exceeds the value of the critical clutch speed, the weights 12 of the centrifugal clutch device 10 associated with this first flywheel 4 come into engagement with the bell 11 of the second flywheel or first intermediate flywheel 5, which is then driven and rotates at the same speed as the first flywheel 4 and the second shaft 2. Therefore, if it is assumed that the centrifugal clutch devices of the intermediate flywheels 5 to 8 are identical to the centrifugal clutch device of the first flywheel 4, the weights 12 associated with the intermediate flywheels 5 to 8 will successively come into engagement with the bells 11 respectively secured to the following flywheels of the series, that is to say the flywheels intermediaries 6 to 8 and the last flywheel 9. All the flywheels are thus coupled 2 to 2 and form with the second shaft an assembly rotating at a speed greater than the critical clutch speed.

 When the speed of the second shaft 2 begins to decrease, this reduction in speed is obviously reduced or limited by said rotating assembly, which initially behaves like a single composite flywheel restoring part of the kinetic energy stored during the acceleration phase. When the speed of the second shaft 2 decreases until it reaches and then exceeds the declutching threshold, which corresponds approximately to the critical clutch speed, the weights 12 of each of the centrifugal clutch devices 10 fall back into the disengaged position, thereby freeing all the flywheels 4 to 9 relative to each other, while the flywheel 4 keyed to the second shaft 2 continues to restore its energy. However, as soon as the speed of the second shaft 2 decreases more rapidly than that of the released flywheels 5 to 9, the freewheel devices 22 of these flywheels enter the locked state with respect to the second shaft 2 and the flywheels 5 to 9 restore their energy again to the second tree by reducing its decrease in speed.

 According to the above, in the case where the centrifugal clutch devices 10 of the flywheels 4 to 8 are identical, said flywheels are successively engaged two by two, from the first flywheel 4 to the last flywheel 9, as soon as the speed of the second shaft exceeds the critical clutch speed. On the other hand, the declutching takes place almost simultaneously for all these flywheels as soon as the decreasing speed of the second shaft reaches a value less than a declutching speed assumed to be approximately equal to the critical clutch speed. the flywheels 4 to 9 thus being released with respect to each other, the speed of the second shaft 2 must also be sufficiently lower than the proper speed of each of the flywheels 5 to 9 so that their associated freewheel device 22 switches to blocked state.

Consequently, while the speed of the second shaft 2 decreases, the flywheels pass substantially together from the engaged state to the disengaged and free state, then from the free state to the blocked state, thus determining two zones of - blows in the operation of the second shaft 2.

 Under these conditions, it is desirable that the centrifugal clutch devices 10 respectively associated with the flywheels 4 to 8 operate for different critical speeds, which makes it possible to eliminate a large part of the jolts and, moreover, to extend the range of operating speeds of the entire inertia rotary device. More specifically, according to an essential feature of the invention, all the flywheels 4 to 9 cooperate two by two for critical speeds going from the first to the last flywheel, that is to say that the critical speeds of the clutch and disengage of the centrifugal clutch devices 10 go up according to the row of the flywheel considered, from the first flywheel 4 to the last flywheel with a clutch device or the penultimate flywheel 8 of the series.

 This can be done in a number of ways. For example, the flyweights associated with each flywheel may have a mass going up according to the rank of the flywheel considered, or the return members of the flyweights associated with each flywheel may have an elastic power going up according to the rank of the flywheel considered, or the pivot axes of the peripheral weights associated with each flywheel can be arranged along a circumference whose radius decreases according to the rank of the flywheel considered.

 According to a particularly simple embodiment, it is possible to modify the mass of the weights 12, respectively associated with each of the flywheels 4 to 8, by simply increasing their thickness, from the first flywheel 4 to the penultimate flywheel 8 of the series . In FIG. 1, a relative increase in thickness is shown schematically, affecting the weights 12 respectively associated with the flywheels 4, 5, 7 and 8.

 According to the above, the first flywheel 4 comprises a first centrifugal clutch device intended to cooperate, for a first critical speed, with the bell of the first intermediate flywheel 5, the latter comprising a second centrifugal clutch device intended to cooperate, for a second critical speed greater than the first, with the bell of the second intermediate flywheel 6, the latter comprising a third clutch device intended to cooperate, for a third critical speed greater than the second, with the bell of the third flywheel intermediate 7, and so on, the last intermediate flywheel 8 comprising a last centrifugal clutch device intended to cooperate, for a last critical speed greater than the previous one, with the bell of the last flywheel 9.

 During operation, as the speed of the second shaft 2 increases, the flyweights 12 associated with each of the flywheels come into engagement with the bell 11 associated with each of the following flywheels in the series for increasing staggered critical speeds.

Conversely, as the speed of the second shaft decreases, the centrifugal clutch devices release the flywheels one after the other - and no longer in a substantially simultaneous manner. Thus, the freewheel device associated with each released flywheel can generally go into the blocked state and restore its energy before the other flywheels still engaged are released. In the event that the speed of the second shaft 2 has not reached a value sufficient to allow the clutch of the last flywheel (s) in the series, these flywheels remain substantially fixed and in the unlocked state during rotation and deceleration of the second shaft 2. Consequently, these non-clutched flywheels do not participate in the operation of the entire rotary inertia device, but do not interfere in any way. To take account of friction, it is however preferable to study the staggering of critical speeds as a function of the range of speeds planned for the second shaft.

 By way of example, the invention is applicable in particular in a road vehicle, the first shaft being constituted by the vehicle transmission shaft. Depending on the type of vehicle, inertial rotary devices can be used in the tractor and / or in the trailer in order to recover energy when the vehicle slows down.

it is clear that the use of one or more devices according to the invention makes it possible to store energy during acceleration of the shaft, in particular when the vehicle is descending, and to recover part of this energy during decelerations of the tree, in particular when the vehicle climbs a hill. Consequently, a certain regulation of the speed of the shaft is obtained and, more generally, an increase in the average speed of the vehicle.

 To avoid the drawbacks of the gyroscopic effects determined by the operation of the assembly of the rotary device as described so far, the latter can be split and include two identical series of flywheels, associated with second shafts which are coupled separately , via synchronized clutches, to a return member associated with the first shaft and determining their simultaneous rotation in opposite directions.

 it is understood that the present invention has only been described and shown for explanatory purposes, but in no way limiting, and that any modification may be made to it, in the field of technical equivalences, without going beyond its ambit.

Claims (10)

 1. Rotary inertia device, of the energy recovery type, comprising a first shaft connecting a motor and a user device, rotary device characterized in that it comprises a second shaft coupled to the first via a clutch and a series of flywheels arranged coaxially and side by side on the second shaft and comprising a first flywheel secured to said second shaft and comprising a first centrifugal clutch device intended to cooperate, for a first critical speed, with at least one intermediate flywheel of the bell type surrounding the first flywheel, this intermediate flywheel being mounted on said second shaft by means of a freewheel device and comprising a second centrifugal clutch device intended to cooperate, for a second critical speed, with a last flywheel of the bell type surrounding the intermediate flywheel, this latter flywheel being mounted on said second shaft by means of a di freewheeling device.  2. Rotary device according to claim 1, characterized in that it comprises a series of intermediate flywheels associated with the first and last flywheels, all these flywheels each comprising a centrifugal clutch device except the last flywheel, each being of the type with bell and freewheel device except the first steering wheel, and cooperating two by two for critical speeds increasing from the first to the last steering wheel.  3. Rotary device according to one of claims 1 or 2, characterized in that each centrifugal clutch device comprises identical peripheral weights each of which is pivotally mounted on a cheek of the flywheel considered, is provided with a elastic return and has a cylindrical surface of shape complementary to that of an internal wall of the bell of the steering wheel according to the series.  4. Rotary device according to claim 3, characterized in that the elastic return member is a torsion bar, one end of which is secured to the flyweight and the other end of which is secured to the cheek.  5. Rotary device according to any one of claims 1 to 4, characterized in that the weights associated with each flywheel have a mass increasing according to the rank of the flywheel considered, from the first to the penultimate flywheel of the series .  6. Rotary device according to any one of claims 1 to 4, characterized in that the return members of the weights associated with each flywheel have an elastic power increasing according to the rank of the flywheel considered, from the first to the front- last steering wheel in the series.  7. Rotary device according to any one of claims 1 to 4, characterized in that the pivot axes of the peripheral weights associated with each flywheel are arranged along a circumference whose radius decreases according to the rank of the flywheel considered, from the first on the penultimate steering wheel in the series.  8. Rotary device according to any one of claims 1 to 7, characterized in that the first and second shafts are coaxial, the second shaft being tubular and mounted for free rotation around the first.  9. Rotary device according to any one of claims 1 to 7, characterized in that it is double and comprises two identical series of flywheels, associated with second shafts QA are coupled separately, via d 'synchronized clutches, to a return member associated with the first shaft and determining their simultaneous rotation in opposite directions.  10. Use of the inertial rotary device according to any one of claims 1 to 9, in particular in a road vehicle, the first shaft being constituted by the transmission shaft of said vehicle.