FR2478750A1 - MECHANISM FOR CONTROLLING THE FLAT PITCH OF AERODYNAMIC AIR PRESSURE TURBINE - Google Patents

Abstract

THE INVENTION RELATES TO A PERFECTED MECHANISM FOR CONTROL OF THE PITCH OF A TURBINE VANE DRIVEN BY AERODYNAMIC AIR PRESSURE. THIS MECHANISM INCLUDES A CONTROL ELEMENT 23 MOUNTED SO AS TO BE ABLE TO EXECUTE AN ALTERNATIVE MOVEMENT ALONG THE CENTRAL AXIS 17 OF A HUB ASSEMBLY 12. A CONTROL UNIT 24 IS ATTACHED TO ONE END OF ELEMENT 23 AND A SEAT 32 OF SPRINGS 47, 48 IS ATTACHED TO THE OTHER END. A COUNTERWEIGHT 56 IS FIXED TO THE FIN 11 AND INCLUDES A PIN 59 WHICH IS ENGAGED WITH THE CONTROL CALIPER 24. A SPRING 63, PLACED BETWEEN THE ASSEMBLY 12 AND THE CALIPER 24, PLACES THE FIN 11 IN THE LARGE PITCH POSITION WHEN IT IS AT REST. A MASSELOTTE 39, MOUNTED ON THE HUB ASSEMBLY 12, BEARING AGAINST A SLIDING ELEMENT 41 IN ORDER TO MOVE IT TO MOVE WING 11 FROM THE LARGE PITCH POSITION TO A SMALL PITCH POSITION WHEN THE IMPELLER IS PLACED IN A FLOW AIR. FIELD OF APPLICATION: EMERGENCY EQUIPMENT FOR AIRCRAFT.

Description

The invention relates to an improvement made to the control of

  fins of a turbine with aerodynamic air pressure. For many years, aircraft have normally provided backup equipment that provides power and is used in the event of a power supply failure, such equipment being in the form of turbines or air-driven fans lowered in the air. airflow to use the relative speed of the aircraft relative to the ambient air to rotate the turbine blades or propellers. The rotation imparted to the fins under the effect of their displacement in the air is then used for driving an electrical generating equipment or for supplying hydraulic power to the hydraulic circuit of the aircraft during the aforementioned periods lack of energy. These air-driven propeller devices typically comprise regulating mechanisms which are intended to regulate the rotational speed transmitted from the propellers to electrical or hydraulic devices which are designed to operate with optimum efficiency at a desired speed.

given speed or setting.

  U.S. Patent Nos. 3,003,613 and 2,876,847 describe examples of the best embodiments designed for this purpose in US Pat.

the prior art.

  The above-mentioned patent NI 3,013,613 describes a device in which the regulator control mechanism comprises, as shown in FIGS. 1 and 3 of the aforementioned patent, regulator weights 64 which are connected, by two axes 74, 78 and a connecting rod. 76, respectively, to a feeder 67 and to a slide assembly 42. This assembly 42 comprises two axes 80 which are connected to the inner ends of rods 82 whose outer ends are articulated on crank pins 84. The latter are carried by crank arms 86 which are connected to a

  trunnion 60 fixed to the blade whose pitch must be controlled.

  Auxiliary counterweights 70 are also fixed rigidly

  60. The mechanism according to the invention, described in more detail below, eliminates practically all the axes and all the linkages necessary for the device described in the above-mentioned patent NI 3,013,613, which makes it possible to obtain a much more efficient mechanism, by design, to control the pitch of blades or fins

according to their speed.

  The above-mentioned patent NI 2,876,847 is particularly

  interesting by the fact that it emits the idea of positioning the blades of the propeller used at large when the entire device is in a fixed position or storage. The device described in this patent realizes the positioning in large pitch of a propeller blade 31 by means of a coil spring 56 which is wound around the foot of the blade and which is fixed to pins 55, 63 of so that when the device is in a fixed position, the coil spring 56 contracts and rotates the blades 31 to a position of large pitch. The mechanism according to the invention, described below, avoids having to bend a helical coil spring, but it uses direct transmission and in a straight line, to the blade or blade to be controlled, energy stored in a spring compressed, this transmission being effected by

  via a device with axis and stirrup.

  The invention thus relates to an improved blade pitch or vane control mechanism for an air driven blade or fin or turbine blade and rotatably mounted in a hub assembly. . The control mechanism includes a drive member mounted to reciprocate along the central axis of the hub assembly. In the preferred embodiment of the invention, the drive element comprises a control member fixed at one end, and a support member at the other end. A centrifugal force sensitive device, operatively connected to the blade or fin, has an axis that engages closely with the controller. A spring is mounted between the hub assembly and

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  the control member to give the blade or blade a large pitch position when the blade or fin and the hub assembly are retracted. A slider is mounted on a portion of the hub assembly to reciprocate along the central axis. A spring is disposed between the support member and the sliding member. A flyweight, mounted on the hub assembly, is in contact with the slider. The rotation of the hub assembly acts on the flyweight to move the sliding member and thereby cause the blade or fin to pass from the large pitch to the small pitch, the centrifugal force sensitive device then being able to control the pitch of the

blade or fin.

  In one embodiment of the invention, the centrifugal force-sensitive device is in the form of a counterweight attached to the blade or fin and, in another embodiment of the invention, this device is sensitive to centrifugal force. comprises a mass which is sensitive to centrifugal force and which is pivotably attached to the hub assembly, a part of, this

  mass engaging the control member.

  The subject of the invention is therefore an improved mechanism for controlling the pitch of a blade or fin, in which springs, arranged axially and coinciding with the central axis of the fins of a turbine driven by air, cooperate with a minimum number of mechanical devices in order to perform a very

no fins.

  The invention also relates to an improved mechanism for regulating and controlling the fin pitch, for use with an air driven turbine without the need to implement linkages and transmission shafts. of movements, which makes it possible to obtain a very sensitive mechanism, with losses

  by reduced mechanical hysteresis.

  The mechanism according to the invention allows the wings, when retracted, to remain in the position of large pitch, which increases the ability of the mechanism to withstand sudden shocks applied to the fins in the case where the control mechanism is influenza while it is retracted, or in the event of a governor spring failure. The mechanism according to the invention exerts several control forces of the pitch of fins using, with the counterweights fixed to the vanes, articulated masses, sensitive to the centrifugal force and functionally connected.

  fins whose step is to order.

  For this purpose, the invention relates to an air-driven blade or blade of a propeller or turbine, comprising a hub assembly having a central longitudinal axis and rotatably mounted on a support

  by driving an output shaft to which it is connected.

  The fin or blade to be controlled is rotatably mounted in the hub assembly. A pitch control mechanism of the blade or fin comprises a regulator drive element mounted to

  to be able to turn and perform a reciprocating movement

  around and along the central longitudinal axis. In the preferred embodiment of the invention, the regulator drive member comprises a yoke or a control member at a first end, and a seat or member

  spring support at the other end.

  A centrifugal force sensitive device attached to the blade or vane has an eccentric axis which is also attached to this device. The shaft is engaged closely with the caliper. A spring is placed between a portion of the hub assembly and the yoke to provide the blade or fin with a large pitch position when the blade or fin and the hub assembly are retracted or stored. A governor slider is mounted on a portion of the hub assembly to rotate and reciprocate respectively about and along the longitudinal centerline. A spring is disposed between the seat and the slider of the regulator. A flyweight is rotatably mounted to the hub assembly and a portion of the flyweight engages the governor slider to rotate the hub assembly to act on the flyweight to move the governor slider and thus pass the blade or fin large step to small step, the device sensitive to centrifugal force can then control the pitch of the blade or fin. In another embodiment of the invention, the centrifugal force-sensitive device comprises a counterweight attached to the blade or fin, the axis being attached to the counterweight. In addition, a centrifugal force sensitive mass is rotatably mounted on the hub assembly. Part of this mass engages the stirrup. The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting examples and in which: FIG. 1 is a perspective view of a

  turbine fin assembly with air pressure

  dynamic, comprising the mechanism according to the invention; - Figure 2 is a section along the line 2-2 of Figure 1; and FIG. 3 is a partial diagrammatic section, similar to that of FIG. 2, of a second

  embodiment of the mechanism according to the invention.

  Figure 1 shows in perspective how the control mechanism of the pitch of the blades of a turbine air pressure aerodynamic, shown in solid lines, is attached to a leg facing downwards and shown in dashed lines. When the aerodynamic air pressure turbine is not used, it is returned to the fuselage of the aircraft (not shown). In Figure 1, the blades or blades 11 and 11a of the turbine are shown

  in their position of great step. The following description

  will indicate in more detail how the fins 11 and 11a are placed in the position of large step for storage purposes, and how the control mechanism according to the invention passes these fins l and liia large step at a small step and then carries controlling the pitch of said fins to produce a constant output speed. The fins 11 and 11a are rotatably mounted in a hub assembly 12 and a hood 15 is attached thereto.

  hub by means of screws, such as that shown in 15a.

  FIG. 2 represents the preferred embodiment of the invention and shows in section the aerodynamic air pressure turbine blade assembly shown in full lines in FIG. 1. In this figure, only the fin 11 and the control mechanism are therefore represented. It is evident that the fin 11 shown in FIG. 1 comprises the same control mechanism as that described hereinafter for the fin 11. The latter is shown as being mounted so as to be able to rotate in a hub assembly 12. This assembly 12 is itself mounted so as to rotate on a support 13 shown in dashed lines. The hub assembly 12 includes a control shaft 14 rotatably mounted in ball bearings 16 and 16a. This

  together 12 rotates about a central longitudinal axis 17.

  It comprises an end plate 18 fixed at its periphery to this assembly by means of bolts such as that represented at 19. The end plate 18 is made in one piece with the control shaft 14 so that the 12 together with the hub 14 and the shaft 14 rotate about the central longitudinal axis 17. The control shaft, although this is not shown in the figures, is coupled to a device to be driven, for example a generator or a hydraulic device. The hub assembly 12 comprises a support portion 21 which is made in one piece with a tubular element 22 for supporting this assembly. A shaft or control member 23 of a regulator is mounted so as to be reciprocable within the tubular member 22. This control member 23 can reciprocate and can also rotate. A yoke 24, attached to the right end of the regulator drive shaft 23 as shown in FIG. 2, includes a plate 26 which is held tightly against a stepped spring seat 27. A self-locking device 15 with nut and washer firmly secures the bracket 24 in position on the control element 23 of the regulator. Shims 28 and 29 are disposed between the stepped seat 27 and a shoulder 31 of the control element 23 of the regulator. A seat 32 of springs is fixed by threads 33 and 34 to the left end of the control shaft 23 of the regulator. The seat 32 is held in place by a self-locking nut 36. A sliding element or slider 41 of the regulator surrounds the tubular element 22 for supporting the hub assembly. This slide 41 can be

  move to the left, as shown in this figure.

  The movement of the slide of the regulator to the right is controlled by a stop lip 42 when the latter comes into contact and abuts against a lip formed at the end of a tubular shaft member 43. This tubular element 43 is shown as being separated from the seat 32 of springs by a shim 44 and the tubular element 22 of the hub support by a shim 44a. The slide 41 of the regulator comprises an annular flange 45 against which coil springs 47 and 48 of compression, as shown. Thrust bearings 51 and 52 are interposed between the left ends of the helical springs 47 and 48 and the seat 32 of the springs. The support portion 21 of the hub assembly 12 comprises a support 20 traversed, as shown, by a pivot axis 25. A flyweight 30, having a contact arm 35, is mounted on the axis 25 in order to pivot with it. It is right to

  note that a rotational movement around the longitudinal axis

  central dinal 17 has the effect of moving the weight 30 outwards, so that the contact arm 35 exerts a certain force on the annular flange 45 which, itself,

  tends to compress the springs 47 and 48, which, through

  middle of the seat 32 of these springs, causes a displacement

  to the left of the control element 23 of the regulator.

  In the upper part of the body, as shown in FIG. 2, it can be seen that the foot 10 of the fin 11 passes through the hub assembly 12 and is fixed to a counterweight assembly 56 by means of a bolt 57. The counterweight assembly 56 is intended to compensate for the torsion moment

  centrifuge of the fin 11 and to produce an additional effort.

  to tend to place the wings in the position of big step.

  The counterweight 56 is keyed on the foot 10, as shown, in order to rotate with it. The fin 11 and its foot 10 are rotatably mounted in the hub assembly 12 and are held in place by a thrust bearing 58. An axis 59, pointing downwards, is fixed eccentrically to the counterweight 56 and has an end portion 61 cam follower. This extreme stretch 61

  is engaged closely with the stirrup 24, as shown.

  A helical compression spring 63 is shown in position between a shoulder 62 of the hub assembly 12 and the stepped spring seat 27. The function of the helical compression spring 63 is, when the device is at rest, to force-rotate, via the stepped seat 27 and the locking pin 59 and its extreme cam follower section 61, the counterweight 56 and

  the fin 11 to a position of large step for storage.

  In use, while the device is in the stored or retracted state, the fin 11 is in the large position not shown. The initial action of the flow of air on the fin 11 is to generate a high starting torque which is transmitted by the foot 10 of the fin to the hub assembly 12. When this set begins to rotate, the weight 30 also turns with him. The flyweight 30 is subjected to a centrifugal force which increases with the speed, so that the contact arm 35 moves the annular flange 45 to the left, as shown in FIG. 2. This movement to the left is transmitted by the helical springs. 47 and 48 of compression, the seat 32 and the control element 23. The stirrup 24, which is fixed to the control element 23 and can slide against the cam follower 61 of the axis 59 of the counterweight, rotates the fin 11, fixed to the counterweight 56, initially to a position step by step. When the entire device reaches its nominal working speed, the counterweight 56 acts to control the pitch of the fin by compressing

the springs 47 and 48.

  Figure 3 shows a partial section another embodiment of the invention. Some members of this embodiment such as bearings, etc., do not

  are not shown, Figure 3 being a schematic view.

  In FIG. 3, the hub assembly 72 and cowl 73 cooperate to center and support a tubular member 74 for supporting the hub assembly, which support member 74 extends along the central longitudinal axis 76. The hub assembly 72 is rotatably mounted on bearings 71. A control shaft 70 is attached to the assembly 72 in the same manner as described for the corresponding member of FIG. shouldered 75 is made in one piece with the cover 73, as shown. The support member 74 has, at its right end, an annular lip 77 constituting a spring seat. A slide member or regulator slide 78 is mounted to reciprocate the tubular support member 74 of the hub assembly. The left end of the slider 78 is made in one piece with an annular flange 79 whose outer edge has a seat profile 81 of a spring. The right end of the regulator slide 78 terminates with an outwardly projecting flange 82 as shown. A helical compression spring 83 is disposed between the annular lip 77 and the flange 82 to

  to act on the slide 78 of the regulator.

  A control element 84, made in one piece with a stirrup 86, is concentrically mounted on the slide 78 of the regulator in order to be able to reciprocate. The stirrup 86 consists of a plate 87, a tubular median section 88 and a spring seat 89. A helical compression spring 91 is fitted between the annular flange 79, which has the seat profile 81, and the seat 89. A flyweight 92 is supported by a pivot axis 93 which is fixed to a portion of the hood 73.

(not shown)

  The turbine blade 101, shown in dashed lines, is attached to a counterweight 102 in the same manner

  that the fin 11 of Figure 2 is fixed to the counterweight 56.

  An eccentric axis 103, comprising a sliding block 104, is made in one piece with the counterweight 102 and is

  slidably adjusted in the caliper 86.

  In the embodiment of the invention shown in Figure 3, an additional centrifugal feeder 106 is mounted on an axis 107 which is attached to the hub assembly 72 by means not shown. The counterweight or counterweight 106 has a contact arm 108 which bears against the plate 87 of the stirrup 86. The role

  centrifugal counterweight 106 will be described in more detail below.

  after. As before, FIG. 3 schematically shows a turbine whose fin 101 is rotatably mounted, with the counterweight 102 and the eccentric axis 103, around the central axis 76. The stirrup 86 is mounted so as to slide on the slider 78 of the regulator and is arranged to engage with the eccentric axis 103 so that axial movement of this stirrup

  86 causes a rotation movement of the fin 101.

  The control member 84, the stirrup 86, the spring 91 and the regulator slide 78 form an assembly which is slidably mounted on the tubular support member 74 of the hub assembly. The helical compression spring 83 maintains this assembly, as indicated above, against the abutment 75 in order to maintain the fin 101 in the large step position when the aerodynamic air pressure turbine is in the rest or storage position. During the ejection, the feeder 92 begins to apply a pressure, via the contact arm 94, to the annular flange 79 of the slider 78 of the regulator and, as the speed increases, it moves the stirrup 86 towards the right, through the spring 91, which has the effect of moving the eccentric axis 103 and the sliding block 104 to the right, in an arc, so that the fin 101 is brought into the small step position. The coil spring 83 compression tends to oppose the movement to the right indicated above. The effect of this movement of the flyweight 92 is such that the fin 101 is placed in its position of smaller step at a speed

  less than the nominal speed of regulation.

  When the speed increases, the centrifugal feeder 106 or, alternatively, the counterweight 102 which exerts a force of the same direction, or these two members, are used together when the speed reaches the nominal value of regulation.-The effect of these The masses, when subjected to the action of the centrifugal force, is to produce a force which exceeds the force required for the compression of the helicoidal spring 91 and which thus brings the fins into a position corresponding to a balanced rotation. When the flow of air on the fin 101 of the turbine stops, the latter stops and the compression coil spring 83 then brings the entire assembly, including the fin 101, in the position of large not

for startup.

  It follows from the previous description that the

  improved mechanism for pitch control of a fin or blade according to the invention comprises axially disposed springs aligned with the central axis of the fins of the aerodynamic air pressure turbine, and cooperating with a minimum number of mechanical members, in order to very effectively adjust the pitch of the fins. The reduced number of mechanically connected members ensures, by its nature, losses by mechanical hysteresis lower than those

  producing in the corresponding prior devices.

  It goes without saying that many modifications can be made to the mechanism described and represented without

depart from the scope of the invention.

he

Claims (10)

  A mechanism for controlling the pitch of a turbine blade (11) driven by aerodynamic air pressure, said fin being rotatably mounted in a hub assembly (12), the mechanism being characterized in that it comprises a control element (23) mounted so as to be reciprocable along a central axis (17) and comprising a control member (24) and a seat (32) attached to said control element, a device (56) responsive to the centrifugal force and comprising an axle (59) interlocked closely with said control member (24), being operably connected to said fin, a return member (63) acting between the hub assembly and the control member to give the vane a large pitch position when said fin and the hub assembly are in the retracted position, a sliding member (41) being mounted on a portion of the assembly (12) at hub in order to be able to execute a move alternating along said central axis, resilient members (47, 48) being disposed between the seat (32) and said sliding member, and a flyweight (30) being mounted on the hub assembly and engaged with the sliding member a rotation of the hub assembly acting on said feeder to move the slider and thereby move the vane from its large step position to a small step position, and then thereafter allow the centrifugal force to control the no fin.   2. Control mechanism according to claim 1, characterized in that the central axis is longitudinal, the hub assembly being rotatably mounted on a support (22) and being coupled to an output shaft (14). . 3. Control mechanism according to claim 2, characterized in that the control member is a stirrup (24) which cooperates with said axis (59) to form a mechanism of motion transformation.   4. Control mechanism according to claim 3, characterized in that said return member and said   resilient members are springs (63, 47, 48). 13 2478750   5. Control mechanism according to claim 4, characterized in that the centrifugal flyweight is   supported by means of a hinge (25).   6. Control mechanism according to claim 5, characterized in that the control member is attached to a first end of said control element (23) and in that the seat (32) is fixed at the other end thereof element control.   7. Control mechanism according to claim 6, characterized in that the return member is disposed between   the hub assembly and said controller (24).   8. Control mechanism according to claim 3, characterized in that the force-sensitive device centrifugal is a counterweight (56).   9. Control mechanism according to the claim   8, characterized in that said axis (59) is attached to the counter   weight and is arranged eccentrically with respect to the axis of rotation of the fin.   10. Control mechanism according to claim 1, characterized in that the centrifugal force-sensitive device comprises a counterweight (102) fixed to the fin (101), said axis (103) being fixed to the counterweight, and a mass ( 106), being responsive to the centrifugal force, being articulated on the hub assembly (72), a portion (108) of this mass   being in contact with said control member (86).