FR3130470A1 - Device for disconnecting a generator driven by a rotor, generator-motor assembly and associated disconnection method. - Google Patents

Abstract

This disconnection device (2) of a generator (1) comprises an internal shaft (6), coupling means (7) of the internal shaft to a drive rotor (5) of the generator, means of disengagement (8) of the coupling means which can be activated in the event of a malfunction of the generator (1), the internal shaft (6) being mounted axially movable between an engagement position in which the internal shaft (6) is coupled to the rotor drive (5) and a disengagement position in which the internal shaft (6) is disengaged from the drive rotor (5) under the action of the disengagement means (8). Figure for the abstract: Fig 1

Description

Device for disconnecting a generator driven by a rotor, generator-motor assembly and associated disconnection method.

The invention relates, in general, to engines equipped with rotating machines.

More particularly, the invention relates to a system for disconnecting a generator driven by an engine, in the event of a malfunction in the generator.

Prior techniques

More and more frequently, rotating machinery such as generators or electric motors are mounted on engines such as aircraft engines. These rotating machines are mounted so that the gearbox or the motor shaft drives the rotating machines in rotation. Aircraft engines are thus supplied with electricity by generators which are driven by the engine. More precisely, the generators are driven via the transmission box, also called gearbox, or directly by the motor shaft.

In the event of a malfunction of one of the elements of the generator, it is necessary to disconnect the generator from the engine in order to protect the engine. Indeed, an additional resistive load can be produced, for example by the short-circuiting torque or by a blocking of the generator, which can cause a risk of fire and/or damage the generator as well as the engine nacelle.

Existing disconnection devices include a shear section at the level of the generator drive shaft capable of breaking from a certain torque threshold transmitted to the generator. However, the design of such a section is only appropriate for a generator rotating at constant speed and whose failure produces a determined torque. Indeed, the breaking torque of the shear section is calibrated well beyond the maximum operational torque transmitted to the generator.

Also, until recently, most generators were wound rotor generators, which allowed a short circuit to be suppressed by cutting off the field current to the rotor.

However, current generators are variable frequency and operate over wider ranges of rotational speeds. In addition, generators are increasingly permanent magnet generators, and shorting them produces a torque that cannot be suppressed as with wound rotor generators. Moreover, the torque of this short-circuiting depends on the speed and the type of short-circuiting.

It is therefore essential to adapt the disconnection systems to current generators.

Some disconnection systems have adapted the shear section technique at the motor drive shaft by making it active with a controlled disconnection system after detection of the malfunction, and include a torque amplification system up to at the level of the breaking torque of the shaft, which makes it possible to cover cases of malfunction over wider ranges of speeds and torques.

In addition, shear section devices, due to their very nature consisting of breaking an axis, are not reusable and must be changed following a malfunction resulting in the activation of the device.

The object of the present invention is therefore to overcome the aforementioned drawbacks and to propose a disconnection device suitable for current and reusable generators.

The present invention therefore relates to a device for disconnecting a generator comprising an internal shaft, means for coupling the internal shaft to a drive rotor of the generator, means for disengaging the coupling means which can be activated in generator malfunction, the inner shaft being mounted axially movable between an engagement position in which the inner shaft is coupled to the drive rotor and a disengagement position in which the inner shaft is disengaged from the drive rotor drive under the action of the disengagement means, the disconnection device comprising automatic locking means and unlocking means controlled remotely from the disengaged position of the internal shaft.

Thus, the disconnection device allows the disconnection and re-engagement of the generator on the drive rotor.

Advantageously, the coupling means comprise teeth or curved splines engaged axially with the drive rotor of the generator when the internal shaft is in the engagement position, and disengaged from the drive rotor when the internal shaft is in disengagement position.

The curved teeth or splines make it possible to disengage the generator by a simple axial displacement greater than the engaged length of the teeth.

Preferably, the disengagement means comprise means for locking in translation and means for braking the rotation of a threaded nut engaged on a thread of the internal shaft.

Thus, it is possible to immobilize the nut, which will cause the axial displacement of the internal shaft which will continue to be driven by the drive rotor until disconnection.

Preferably, the translation locking means are angular contact bearings and the rotation braking means is an electromechanical braking device.

The angular contact bearings are arranged in such a way as to block the translation of the nut.

In one embodiment, the means for locking the disengaged position comprise a stop element able to move radially between an axial locking position of a shoulder of the internal shaft and an axial unlocking position of the shoulder.

Advantageously, the unlocking means comprise a means for lifting the abutment element and a means for returning the internal shaft to the engagement position.

Advantageously, the unlocking means can be activated at zero speed of the drive rotor and cause the re-engagement of the shaft internal to the drive rotor.

In one embodiment, the lifting means is an electromagnet.

Advantageously, the disconnection device according to the invention comprises a monitoring device triggering the disengagement means of the coupling means on the occurrence of a malfunction of the generator.

In one embodiment, the generator is a wound rotor or permanent magnet generator.

The invention also relates to an assembly comprising a motor and a generator, the motor driving the generator in rotation, the generator being equipped with a disconnection device as described above.

Finally, the invention also relates to a method for disconnecting a generator equipped with a connection device as described above and connected to an engine comprising the following steps:

• Detection of an incident;
• Activation of the means of disengagement and increase of the torque delivered by the drive rotor to the internal axis;
• Locking of the internal shaft in the disconnected position.

Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

illustrates a view in longitudinal section of a generator equipped with a disconnection device according to the invention in the engagement position on a drive rotor; And

illustrates a view in longitudinal section of a generator equipped with a disconnection device according to the invention in the locked disengagement position with respect to the drive rotor; And

illustrates a method of disconnecting a generator from a drive rotor according to the invention.

Detailed description of at least one embodiment

We represented on the a view in longitudinal section of a generator 1 equipped with a disconnection device 2 according to the invention.

The generator 1 comprises a rotor 3 and a stator 4. It can be a wound rotor or permanent magnet generator.

In operation, the generator 1, and more particularly the rotor 3 of the generator 1 is driven in rotation by a drive rotor of the generator 5. The drive rotor 5 is more precisely an output shaft of an engine. This engine is for example an engine of a vehicle such as an aircraft.

Nevertheless, the invention is not limited to this configuration, and also relates to a device for disconnecting a generator driven by a gearbox, or transmission box.

The disconnection device 2 comprises an internal shaft 6, means 7 for coupling the internal shaft 6 to the drive rotor 5, a monitoring device and means 8 for disengaging the coupling means.

The internal shaft 6 extends axially in the generator 1 and is fixed to the rotor 3 of the generator 1. More precisely, the rotor 3 is fixed axially on the internal shaft 6. On the other hand, the internal shaft 6 is able to be secured to the drive rotor 5 and to disengage.

More specifically, the internal shaft 6 is mounted axially movable between an engagement position in which it is coupled to the drive rotor 5 and a disengagement position of the drive rotor 5.

On the , the generator 1 is in the operating position and is therefore driven by the drive rotor 5 via the internal shaft 6, which is in the engagement position on the drive rotor 5.

At one of its ends 6a opposite the drive rotor 5, the internal shaft 6 comprises coupling means 7. These coupling means 7 are able to secure the internal shaft 6 to the drive rotor 5. More particularly, these coupling means 7 comprise teeth or curved splines engaged axially with the drive rotor 5. Thus, their disengagement is possible by a simple translation of the internal shaft 6 so as to move it away axially of the drive rotor 5 over a distance greater than the length in engagement of the coupling means 7 on the drive rotor 5.

In the position of the device 2 illustrated on the , the drive rotor 5 is capable of rotating the internal shaft 6 secured to the rotor 2. The generator 1 is therefore in the normal operating position.

The disconnection device 2 comprises a monitoring device not shown in the figures. This monitoring device comprises sensors capable of detecting a malfunction in the generator 1, such as a short-circuit or a blockage of the generator. The monitoring device is also capable of triggering the disengagement means 8 of the coupling means 7, when a malfunction occurs.

The disengagement means 8 of the coupling means are able to deactivate the coupling means 7. More particularly, the disengagement means 8 when they are activated cause an axial translation of the internal shaft 6 so that the means of coupling 7 disengage from the drive rotor 5, which disconnects the generator 1 from the drive rotor 5 and therefore from the motor.

The disengagement means 8 comprise a nut 9, translation locking means 10 and a means 11 for braking the rotation of the nut 9.

The nut 9 comprises an internal thread by which it is secured to an external thread 6b of the internal shaft 6. The external thread 6b is for example located on the end 6c of the internal shaft 6 opposite the end 6a comprising the coupling means 7.

The translation locking means 10 of the nut 9 are secured to the stator 4 of the generator 1. The translation locking means 10 are in contact with the nut 9 and block its axial translation, without blocking its rotation. For example, the translation locking means 10 of the nut 9 comprise angular contact bearings fixed on the one hand to the stator 4 and on the other hand arranged on the nut 9 so as to lock its axial translation without blocking its rotation driven by the rotation of the internal shaft 6.

The braking and blocking means 11 of the rotation of the nut 9 is capable of braking the rotation of the nut 9 driven by the rotation of the internal shaft 6, preferably until the total blocking of the rotation of the nut 9. The braking and locking means 11 is for example an electromechanical braking device capable of delivering a braking torque opposite to the torque transmitted by the drive rotor 5 and the internal shaft 6 to the nut 9 and to the short-circuiting torque in the event of a malfunction.

The translation locking means 10 are permanently activated while the braking and locking means 11 is only activated in the event of a malfunction. Thus, when the generator 1 operates and is driven in rotation by the drive rotor 5 via the internal shaft 6, the nut 9 also undergoes a rotational movement driven by the internal shaft 6, but does not translate axially. .

On the other hand, in the event of a malfunction, the nut 9 is able to be immobilized in rotation and in translation, the braking and locking means 11 then also being activated.

When it detects a malfunction, the monitoring device activates the disengagement means 8 of the coupling means. The disengagement means 8 then block the rotation and the translation of the nut 9, which is then immobilized. The immobilized nut 9 then exerts a resistance force on the rotating shaft 6 which causes an axial translation of the internal shaft 6 so that the shaft 6 moves axially away from the drive rotor 5. The axial translation of the internal shaft 6 causes the disengagement of the coupling means 7 from the drive rotor 5 once the axial translation length of the internal shaft 6 is greater than the length in engagement of the coupling means 7 on the drive rotor 5.

The disconnection device 2 also comprises locking means 12 and unlocking means 13 of the internal shaft 6 in the disengaged position, intended to prevent unwanted re-engagement of the internal shaft 6, after its disengagement from the rotor 5.

The locking means 12 are automatic and the unlocking means 13 are remote controlled.

The locking means 12 make it possible to maintain the disconnected position of the generator 1 and to avoid any re-engagement. These locking means 12 can only be engaged after disengagement over a stroke corresponding to the overall relative displacement between the drive rotor 5 and the internal shaft 6, in order to ensure complete disengagement in all operating cases. .

The locking means 12 of the disengaged position comprise an abutment element 12a and a shoulder 12b of the internal shaft 6.

This stop element 12a is able to move radially between an axial locking position of the shoulder 12b of the internal shaft 6 represented on the and an axial release position of the shoulder 12b. More particularly, the stop element 12a is arranged in the generator 1 so as to be on the path of the shoulder 12b of the internal shaft 6 in axial translation during its disengagement movement. The stop element 12a is then in the position of axial blocking of the shoulder 12b. The stop element 12a is also arranged in the generator 1 so as not to be in the path of the shoulder 12b of the internal shaft 6 in axial translation when it is reengaged. The stop element 12a is then in the axial unlocking position.

The stop element 12a comprises a face 12c positioned opposite the shoulder 12b of the internal shaft 6 in the engaged position on the drive rotor 5.

The stop element 12a further comprises a face 12d positioned facing the shoulder 12b of the internal shaft 6 in the disengaged position of the locked rotor 5. The face 12d extends substantially radially relative to the axis of translation of the internal shaft 6.

The shoulder 12b comprises a face 12e and a face 12f. The 12e face extends substantially radially as far as a free radial end which is connected to the 12f face.

The face 12f of the shoulder 12b is positioned opposite the face 12c of the abutment element 12a when the internal shaft 6 is in the engaged position on the rotor 5. Thus, the face 12f is capable of coming into contact with the face 12c of the abutment element 12a when the internal shaft 6 is in disengagement translation of the rotor 5 and in disengagement locking movement.

Face 12e is positioned opposite face 12d of stop element 12a when internal shaft 6 is in the disengaged position of rotor 5 and locked. Thus, face 12e is able to come into contact with face 12d of abutment element 12a when internal shaft 6 is disengaged from rotor 5 in the locked position.

The face 12c is configured to allow the locking of the internal shaft 6 in axial translation. More precisely, the face 12c extends between two radial ends and is oblique with respect to the axis of translation of the internal shaft 6 so that the end of the face 12c closest to the axis of translation of the internal shaft 6 is axially closer to the plane perpendicular to the axis of translation of the internal shaft 6 and including the face 12d than the second radial end of the face 12c.

Possibly, the face 12f is also oblique with respect to the axis of translation of the internal shaft 6, so as to be parallel to the face 12c.

In this way, the stop element 12a does not block the axial translation of disengagement of the internal shaft 6, and blocks the axial translation of reengagement of the internal shaft 6 in the disengaged and locked position. Indeed, when the internal shaft 6 is in axial disengagement translation of the rotor 5, the face 12f of the shoulder 12b comes into contact with the oblique face 12c of the stop element 12a, and applies a force which will move radially the stop element 12a and allow the complete passage of the shoulder 12b.

The abutment element 12a is connected to a biasing means 14 such as a compression spring tending to return the abutment element 12a to the axial locking position of the shoulder 12b.

In other words, under the effect of the contact of the faces 12c and 12f due to the axial movement of disengagement of the internal shaft 6 which is against the biasing means 14, the abutment element 12a moves radially to release the axial translational movement of the shoulder 12b up to the locking position, and resumes an axial locking position of the shoulder 12b once the locking position has been reached by the internal shaft 6.

Indeed, once the shoulder 12b has crossed the abutment element 12a axially, the abutment element 12a is returned to the axial locking position by the biasing means 14. This situation is illustrated on the , which illustrates the internal shaft 6 in the disengaged and locked position of the drive rotor 5.

The shoulder 12b on the has passed through the stop element 12a and the internal shaft 6 is locked in the disengaged position. In the event of translational movement in the opposite direction of the internal shaft 6 so that the internal shaft 6 approaches the drive rotor 5, the shoulder 2b is blocked by the stop element 12a in the axial blocking position. , and more particularly by the face 12d of the abutment element 12a perpendicular to the shoulder 12b.

The locking of the internal shaft 6 in the disengaged position of the drive rotor 5 is therefore obtained only after a minimum axial stroke of the internal shaft 6 under the effect of the residual kinetic energy generated by the rotation of the drive rotor 5. Indeed, when the disengagement means 8 are activated, the internal shaft 6 driven in rotation by the drive rotor 5 moves axially then disconnects from the rotor 5 under the effect of the locking in rotation of the nut 9. Once disconnected from the drive rotor 5, the assembly comprising the internal shaft 6 and the rotor 3 continues to be driven in rotation by the rest of the kinetic energy which had been transmitted to it by driving the drive rotor 5.

Thus, the locking means 12 are automatic in that they are mechanically activated independently of the will or action of a user such as a pilot, and caused solely by the movement of the internal shaft 6.

The unlocking means 13 comprise a means 13a for lifting the abutment element 12a and a means 13b for returning the inner shaft 6 to the engagement position.

The unlocking means 13 can be activated at zero speed of the drive rotor 5.

The lifting means 13a is an electromagnet, the activation of which will radially attract the abutment element 12a, the attraction exerted by the electromagnet being greater than the return force of the spring 14. In this way, the stop 12a is moved from its axial locking position to its axial unlocking position by the activation of the lifting means 13a. The return means 13b in the engagement position of the inner shaft can then cause the axial displacement of the inner shaft 6 from the disengagement position to the engagement position on the drive rotor 5. The means 13b is for example a return spring in the engagement position positioned axially in abutment against the internal shaft 6.

Thus, the unlocking means 13 make it possible, when activated, to return the generator 1 to the operating configuration of the .

The unlocking means are therefore controlled remotely, since they are controlled by a user such as the pilot who issues an activation command, for example by pressing a button, causing the lifting element 13a to be activated. In other words, the unlocking means 13 do not require manual intervention by a user directly on the device 2.

There illustrates the steps of a method for disconnecting the generator 1 equipped with the device 2 for disconnecting the drive rotor 5.

In the initial state, generator 1 is rotated by drive rotor 5 via internal shaft 6.

In a first step 15, the monitoring device detects a malfunction in the generator 1.

In a second step 16, the monitoring device activates the disengagement means 8 so that the internal shaft moves axially away from the drive rotor 5. At the same time, the drive rotor 5 increases the torque it transmits to the internal shaft 6, so as to facilitate and ensure its disengagement by increasing its kinetic energy.

In a third step 17, the internal shaft 6 is disengaged, and retains a residual kinetic energy which allows the continuation of its axial movement until the activation of the locking means 12 from the disengagement position. Step 17 therefore consists of locking the internal shaft in the disconnected position.

In a step 18, the unlocking means 13 are activated the internal shaft is returned to the engagement position on the drive rotor 5.

Claims (12)

Device (2) for disconnecting a generator (1) comprising an internal shaft (6), means (7) for coupling the internal shaft to a drive rotor (5) of the generator, disengagement means (8) coupling means which can be activated in the event of a malfunction of the generator (1), the internal shaft (6) being mounted axially movable between an engagement position in which the internal shaft (6) is coupled to the rotor drive (5) and a disengagement position in which the internal shaft (6) is disengaged from the drive rotor (5) under the action of the disengagement means (8), the disconnection device (2) comprising automatic locking means (12) and unlocking means (13) controlled remotely from the disengaged position of the internal shaft (6). Device (2) according to Claim 1, in which the coupling means (7) comprise crowned teeth or splines engaged axially with the drive rotor (5) of the generator when the internal shaft (6) is in position. engagement, and disengaged from the drive rotor (5) when the inner shaft (6) is in the disengaged position. Device (2) according to Claim 1 or 2, in which the disengagement means (8) comprise means for locking in translation (10) and means for braking the rotation (11) of a threaded nut (9) engaged on a thread (6b) of the internal shaft (6). Device (2) according to claim 3, in which the translation locking means (10) are angular contact bearings and the rotation braking means (11) is an electromechanical braking device. Device (2) according to Claim 4, in which the means (12) for locking the disengaged position comprise an abutment element (12a) able to move radially between an axial locking position of a shoulder (12b) of the internal shaft (6) and an axial release position of the shoulder (12b). Device (2) according to claim 4 or 5, in which the unlocking means (13) comprise a lifting means (13a) of the abutment element (12a) and a means of returning to the engagement position (13b) of the internal shaft (6). Device (2) according to Claim 6, in which the unlocking means (13) can be activated at zero speed of the drive rotor (5) and cause the internal shaft (6) to reengage with the drive rotor (5 ). Device (2) according to claim 6 or 7, wherein the lifting means (13a) is an electromagnet. Device (2) according to one of claims 1 to 8 comprising a monitoring device triggering the disengagement means (8) of the coupling means on the occurrence of a malfunction of the generator (1). Device (2) according to one of Claims 1 to 9, in which the generator (1) is a wound-rotor or permanent-magnet generator. Assembly comprising a motor and a generator (1), the motor driving the generator (1) in rotation, the generator (1) being equipped with a disconnection device (2) according to one of Claims 1 to 10. Method for disconnecting a generator (1) equipped with a connection device (2) according to one of Claims 1 to 11 and connected to an engine, comprising the following steps:

• Detection (15) of a malfunction;
• Activation (16) of the disengagement means and increase of the torque delivered by the drive rotor to the internal shaft;
• Locking (17) of the internal shaft in the disconnected position.