Electric actuator for heating, ventilation and / or air conditioning systems

Abstract

The invention relates to an electric actuator (50) suitable for driving a movable element of a heating, ventilation and / or air conditioning system for a motor vehicle, comprising: an electric motor (2) comprising: a stator (3), a rotor (4) extending along an axis (X), a pinion (5) rigidly connected to the rotor (4), a drive mechanism (6) comprising: a planet carrier (7), at least one planet gear (8) held by the planet carrier (7), the planet gear (8) being adapted to be rotated by the pinion (5), an output ring gear (11) adapted to be rotated by the at least one planet gear (8), a drive sleeve (12) rigidly connected to the output ring gear (11) and adapted to drive the movable element, the drive sleeve (12) having a distance to the electric motor (2) in a direction along the axis (X) of the rotor (4).

Description

Technical Field

[0001] This invention relates to an electric actuator for heating, ventilation, and / or air conditioning systems. A particular application relates to a heating, ventilation, and / or air conditioning system for a motor vehicle, incorporating such an actuator. Background Technology

[0002] The temperature inside the passenger compartment of a motor vehicle is controlled by a heating, ventilation, and / or air conditioning system. This system includes different heat exchangers through which different airflows pass before reaching the passenger compartment. These heat exchangers can heat or cool the different airflows before they enter the passenger compartment. The temperature is controlled by varying the flow rates of the different airflows. To this end, the system includes several movable dampers that can adjust the flow rate of each airflow. The position of each movable damper is controlled by an electric actuator.

[0003] An electric actuator refers to an actuator that includes an electric motor and an actuation mechanism driven by that electric motor. The actuation mechanism allows adjustment of the rotational speed of the electric motor, thereby regulating the force available at the drive socket of the actuator. The airflow speed control damper is rotatable. In this case, the damper is rigidly connected to a rotating shaft, and the electric actuator drives this rotating shaft. The electric actuator must have the smallest possible size to facilitate its integration into heating, ventilation, and / or air conditioning systems.

[0004] A known practice is to propose an electric actuator whose actuation mechanism includes a planetary gear set. This mechanism can achieve a beneficial gear reduction ratio between the electric motor and the actuator's drive sleeve.

[0005] Another known practice is to propose an electric actuator with a hollow electric motor, allowing the damper's shaft to pass through the motor. Therefore, the axial dimension of the actuator is particularly reduced.

[0006] However, this design has a drawback: the hollow drive wheel must have a sufficiently large diameter to allow the damper shaft to pass through. This limits the ratio between the diameter of the outer ring gear of the planetary gear set and the diameter of the drive wheel, which acts as the planetary pinion. Consequently, the gear reduction ratio achievable with this design may be insufficient to provide adequate driving force, or overcoming this deficiency may result in an excessively large electric motor. This increases the cost and size of the electric motor. Summary of the Invention

[0007] This invention proposes to improve this situation by providing an element arrangement for the actuator's drive mechanism that allows for an increase in the gear reduction ratio. Therefore, actuators capable of actuating dampers can be supplied, offering higher strength while maintaining a compact size.

[0008] The present invention therefore provides an electric actuator suitable for driving movable elements of heating, ventilation and / or air conditioning systems for motor vehicles, comprising:

[0009] Electric motor, comprising:

[0010] stator,

[0011] Rotor extending along the axis,

[0012] The pinion rigidly connected to the rotor

[0013] The drive mechanism includes:

[0014] Planetary support,

[0015] At least one planetary gear held by a planet carrier, the planetary gear being adapted to be rotated by a pinion, and an output gear ring adapted to be rotated by said at least one planetary gear.

[0016] A drive sleeve rigidly connected to the output gear ring and adapted to drive movable elements.

[0017] The drive sleeve is at a certain distance from the electric motor along the direction of the rotor axis.

[0018] Therefore, movable components of the heating, ventilation, and / or air conditioning systems do not pass through the electric motor. The electric motor can be sized to optimize the magnetic circuit, as there is no longer a need for a hollow section.

[0019] According to one embodiment, the at least one planetary gear is translatably connected to the planet carrier and rotates freely relative to the planet carrier.

[0020] According to one embodiment, the drive sleeve extends along the rotation axis of the electric motor.

[0021] According to a preferred embodiment of the electric actuator, a pinion rigidly connected to the rotor faces the drive sleeve along the axial direction.

[0022] Therefore, the diameter of the drive pinion rigidly connected to the rotor can be selected to increase the gear reduction ratio between the rotor and the drive sleeve. In particular, the diameter of the drive pinion can be smaller than the diameter of the drive sleeve.

[0023] According to one embodiment of the electric actuator, the drive sleeve includes a recess arranged to receive a protrusion of a movable element, the recess being at least partially closed by a base.

[0024] According to a preferred embodiment, the pinion rigidly connected to the rotor faces the base of the recessed portion of the drive sleeve.

[0025] According to a preferred embodiment, the rotor is outside the stator.

[0026] Advantageously, the at least one planetary gear includes a first gear stage and a second gear stage rigidly connected to the first gear stage, the two gear stages being coaxial and having different diameters.

[0027] As a variant, the at least one planetary gear includes a first gear stage and a second gear stage rigidly connected to the first gear stage, the two gear stages being coaxial and having the same diameter.

[0028] Preferably, the two gear stages of the at least one planetary gear form an integral assembly.

[0029] According to a preferred embodiment, the electric actuator includes an external gear ring fixed relative to the stator.

[0030] According to a preferred embodiment, the first gear stage is adapted to mesh with an external gear ring.

[0031] According to a preferred embodiment, the second gear stage is adapted to mesh with the output gear ring.

[0032] Advantageously, the electric drive includes a housing that accommodates the electric motor and drive mechanism.

[0033] Advantageously, the housing is configured to be fastened to a heating, ventilation and / or air conditioning system.

[0034] Preferably, the stator is received in a cylindrical cavity with a closed base.

[0035] Preferably, the rotor is received in a cylindrical cavity.

[0036] According to one embodiment, the electric actuator includes at least two planetary gears, each planetary gear being translatably connected to a planet carrier and freely rotatable relative to the planet carrier.

[0037] According to a preferred embodiment, the electric actuator includes three planetary gears, each of which is translatably connected to the planet carrier and rotates freely relative to the planet carrier.

[0038] This design allows for satisfactory distribution of internal forces within the actuator and can limit the forces acting on the planetary gear teeth.

[0039] According to another embodiment, the electric actuator includes four planetary gears, each of which is translatably connected to the planet carrier and rotates freely relative to the planet carrier.

[0040] Advantageously, the drive sleeve is radially positioned between the axes of the planetary gears.

[0041] Therefore, the dimensions along the rotation axis of the electric motor are limited.

[0042] According to a preferred embodiment, the drive sleeve and the output gear ring form an integral assembly.

[0043] Preferably, the output gear ring is molded.

[0044] Advantageously, the drive sleeve is adapted to rotate the axis of the movable element.

[0045] The drive sleeve thus has a shape complementary to the shape of the end of the rotating shaft of the movable element. During assembly, the end of the shaft must be simply inserted into the drive sleeve to rigidly connect the two parts for joint rotation.

[0046] According to one embodiment, the drive sleeve includes a spline.

[0047] According to another embodiment, the drive sleeve includes a polygonal periphery.

[0048] Preferably, the drive sleeve includes a shoulder, and the orifice of the actuator housing surrounds the shoulder.

[0049] This shoulder allows for centering and guiding of the drive sleeve within the actuator housing.

[0050] According to one embodiment, the rotor includes a cylindrical wall extending along the axis and a flange extending transversely to the axis.

[0051] Advantageously, the cylindrical wall of the rotor includes the inner surface on which magnets are positioned.

[0052] According to one embodiment, the flange is disc-shaped. The flange can be solid or perforated.

[0053] Advantageously, the pinion and magnet, which are rigidly connected to the rotor, are axially positioned on both sides of the flange.

[0054] According to one embodiment, the stator includes an electromagnetic coil positioned on a printed circuit board.

[0055] Preferably, the printed circuit board is positioned on the substrate of the cylindrical cavity.

[0056] According to one embodiment, the rotor includes a guide shaft that is inserted into a central hole in the stator.

[0057] Therefore, the rotor components are simplified. The axial dimension of the electric motor is reduced.

[0058] According to one embodiment, the stator includes at least three coils arranged in a star shape around a central hole.

[0059] Advantageously, the rotor is made of plastic or metal.

[0060] According to one embodiment, each planetary gear is made of plastic or metal.

[0061] Advantageously, each planetary gear is molded.

[0062] According to a preferred embodiment, the diameter of the second gear stage is smaller than the diameter of the first gear stage.

[0063] The gear reduction ratio between the pinion of the electric motor and the drive sleeve of the actuator depends on the difference in diameter between the two gear stages. The closer the diameters of the two gear stages are, the higher the gear reduction ratio. In other words, the closer the diameters of the two gear stages are, the slower the drive sleeve rotates for a given electric motor speed. This allows for high drive torque, ensuring that the moving parts do not lock up, even under extreme operating conditions.

[0064] The present invention also relates to a heating, ventilation and / or air conditioning system for a motor vehicle, comprising at least one air flow duct and a movable baffle configured to control airflow in the duct, the baffle being configured to be driven by the electric actuator described above. Attached Figure Description

[0065] Further features and advantages of the invention will become apparent upon reading the detailed description of the embodiments, which are given by way of non-limiting examples, in conjunction with the following accompanying drawings. In the drawings:

[0066] Figure 1 This is an overall perspective view of the electric actuator according to the present invention.

[0067] Figure 2 yes Figure 1 Cross-sectional view of the actuator.

[0068] Figure 3 This is a first cross-sectional view of the actuator, which shows the drive mechanism.

[0069] Figure 4 This is a second cross-sectional view of the actuator, which shows the drive mechanism.

[0070] Figure 5 This is a partial perspective view of the stator of an electric motor with an actuator.

[0071] Figure 6 This is a first perspective view of the rotor of the electric motor with actuator.

[0072] Figure 7 This is a second perspective view of the rotor of the electric motor with actuator.

[0073] To make the accompanying drawings easier to read, different elements are not necessarily shown to scale. Detailed Implementation

[0074] Figure 1An electric actuator 50 suitable for driving movable elements of heating, ventilation, and / or air conditioning systems for motor vehicles is shown. The movable element is, for example, a rotary damper, which can distribute the respective flow rates of two airflows that are mixing. Therefore, the temperature of the passenger compartment can be controlled, i.e., adjusted to a desired value. Adjusting the position of the damper allows for adjustment of the distribution between hot and cold air generated by the heating, ventilation, and / or air conditioning system.

[0075] The damper may be a rotary damper mounted on a shaft. The shaft is rotated by an electric actuator 50. An electronic control unit (not shown) controls the position of the movable damper by controlling the current supplying power to the actuator 50. Well-known heating, ventilation, and / or air conditioning systems are not shown.

[0076] Figure 1 This is an overall view of the electric actuator 50. The electric actuator 50 includes a housing 18 that houses the electric motor 2 and the drive mechanism 6. The housing 18 is configured to be fastened to a heating, ventilation, and / or air conditioning system. For this purpose, the housing 18 includes fastening lugs (not shown), through which screws can pass into threaded holes in the heating, ventilation, and / or air conditioning system. Thus, the actuator 50 is fastened to the heating, ventilation, and / or air conditioning system. The housing 18 includes an upper housing 33 and a lower housing 34. The two housings 33 and 34 are rigidly connected, for example, by welding.

[0077] Figure 2 The electric actuator 50 shown in detail includes:

[0078] Electric motor 2, comprising:

[0079] Stator 3,

[0080] Rotor 4 extending along axis X,

[0081] The pinion 5 is rigidly connected to the rotor 4.

[0082] Drive mechanism 6, which includes:

[0083] Planetary Carrier 7,

[0084] At least one planetary gear 8 is held by the planet carrier 7, and the planetary gear 8 is adapted to be rotated by the pinion 5.

[0085] The output gear ring 11 is adapted to be rotated by the at least one planetary gear 8.

[0086] A drive sleeve 12, rigidly connected to the output gear ring 11 and adapted to drive movable elements,

[0087] The drive sleeve 12 is at a certain distance from the electric motor 2 in the direction along the axis X of the rotor 4.

[0088] In other words, there is an axial clearance between the electric motor 2 and the drive sleeve 12. Figure 2 The 'j' symbol is used to mark the 'j'.

[0089] Therefore, the movable elements of the heating, ventilation, and / or air conditioning systems do not pass through the electric motor 2. The electric motor 2 can be sized to optimize the magnetic circuit, since it is no longer necessary to have hollow sections in the rotor and stator to allow the shaft of the movable element to pass through the rotor and stator.

[0090] The electric motor 2 extends along axis X. The drive sleeve 12 extends along the rotation axis X of the electric motor 2. The pinion 5, rigidly connected to the rotor 4, faces the drive sleeve 12 in the axial direction.

[0091] The drive sleeve 12 includes a recess 13 arranged to receive a protrusion of a movable element. The recess 13 is at least partially closed by a base 14. A pinion 5, rigidly connected to the rotor 4, faces the base 14 of the recess 13 of the drive sleeve 12. A gap exists between the pinion 5 and the base 14 along the X-axis. This gap... Figure 2 The 'j' symbol is used to mark the 'j'.

[0092] Because of this arrangement, the diameter of the drive pinion 5, which is rigidly connected to the rotor 4, can be selected to increase the gear reduction ratio between the rotor 4 and the drive sleeve 12. In particular, the diameter of the drive pinion 5 can be selected to be smaller than the diameter of the drive sleeve 12, which facilitates obtaining a high gear reduction ratio.

[0093] Here, the rotor 4 is outside the stator 3. In other words, the stator 4 is located at the center of the electric motor 2. The rotor 4 surrounds the stator 3.

[0094] The drive mechanism 6 of the electric actuator 50 includes a planetary gear set. A pinion 5 forms a planetary pinion in the planetary gear set, which drives the other elements of the planetary gear set. The pinion 5 meshes with at least one planetary gear 8, which is movably connected to a planet carrier 7 and is freely rotatable relative to the planet carrier 7. Advantageously, the electric actuator includes at least two planetary gears 8 and 9, each of which is translatably connected to the planet carrier 7 and is freely rotatable relative to the planet carrier 7.

[0095] In the example described here, the electric actuator 50 includes three planetary gears 8, 9, and 10, each of which is translatably connected to a planet carrier 7 and rotates freely relative to the planet carrier 7. The configuration with three planetary gears allows for satisfactory distribution of internal forces within the actuator and limits the forces acting on the teeth of the planetary gears 8, 9, and 10. Each planetary gear has an axis of rotation. The axes of rotation are parallel to each other.

[0096] The electric actuator 50 also includes an external gear ring 17 fixed relative to the stator 3. The external gear ring 17 has internal teeth. Figure 2 As shown in the figure. The at least one planetary gear 8 includes a first gear stage 15 and a second gear stage 16 rigidly connected to the first gear stage 15, the first gear stage 15 and the second gear stage 16 being coaxial and having different diameters D1 and D2.

[0097] In the scenario described herein, the drive mechanism 6 includes a plurality of planetary gears, each of the planetary gears 8, 9, and 10 including a first gear stage 15 and a second gear stage 16 rigidly connected to the first gear stage 15, the first gear stage 15 and the second gear stage 16 being coaxial and having different diameters D1 and D2.

[0098] Figure 3 and Figure 4 Details of the components of drive mechanism 6 are shown, with particular attention to the planetary gear set. For simplicity, the planet carrier is not shown. As is well known, the planet carrier holds the planetary gears, which are translationally fixed relative to each other, and allows the planetary gears to rotate freely about their respective axes. Each of planetary gears 8, 9, and 10 meshes with the teeth of the outer ring gear 17.

[0099] More specifically, the first gear stage 15 is adapted to mesh with the outer gear ring 17. Because the gear ring 17 is fixed, the rotational motion of the pinion 5 of the electric motor 2 causes the planetary carrier 7 to rotate about the axis X. Figure 3 The point marked 38 represents the contact point between the first gear stage 15 and the outer gear ring 17. The second gear stage 16 is adapted to mesh with the output gear ring 11. The output gear ring 11 has internal teeth.

[0100] Since the first gear stage 15 and the second gear stage 16 of the at least one planetary gear have different diameters, the speed at the contact point between the output gear ring 11 and the second gear stage 16 is non-zero. Figure 4 The point marked with 40 represents the contact point between the second gear stage 16 and the output gear ring 11. Therefore, when the pinion 5 rotates, the output gear ring 11 rotates.

[0101] The output gear ring 11 has a drive sleeve 12. More specifically, the drive sleeve 12 here forms an integral assembly with the output gear ring 11. The output gear ring 11 is molded. The body, teeth, and drive sleeve of the output gear ring 11 form parts of the same component obtained by molding.

[0102] Here, the diameter D2 of the second gear stage 16 is smaller than the diameter D1 of the first gear stage 15. Therefore, the output gear ring 11 has the same direction of rotation as the pinion 5. This arrangement also allows for a reduction in the radial dimension of the actuator at the drive sleeve 12.

[0103] The gear reduction ratio between the pinion 5 of the electric motor and the drive sleeve 12 of the actuator 50 depends on the difference between the diameters D1 and D2 of the first gear stage 15 and the second gear stage 16. The closer the values ​​of the two diameters D1 and D2 are, the higher the gear reduction ratio. In other words, the closer the two diameters are, the slower the drive sleeve 12 rotates for a given speed of the electric motor. Therefore, high drive torque can be obtained, thus ensuring that the movable element does not lock up, even under extreme operating conditions. Figure 3 and Figure 4 In this study, the difference between diameter D1 and diameter D2 was exaggerated.

[0104] In the illustrated example, the first gear stage 15 and the second gear stage 16 of the at least one planetary gear form an integral assembly. Each of the planetary gears 8, 9, and 10 is molded. Each of the planetary gears 8, 9, and 10 is made of plastic. Each of the planetary gears 8, 9, and 10 may also be made of metal.

[0105] from Figure 2 As can be seen, the drive sleeve 12 is radially positioned between the axes of planetary gears 8, 9, and 10. Therefore, the dimensions along the rotational axis X of the electric motor are limited. The incorporation of the actuator is convenient, allowing the same actuator to be used in a wide range of applications.

[0106] The drive sleeve 12 is adapted to rotate the shaft of the movable element. Therefore, the drive sleeve 12 has a shape complementary to the shape of the end of the rotating shaft of the movable element. During assembly, the end of the shaft must be simply inserted into the drive sleeve 12 to rigidly connect the two components for joint rotation. Figure 1 and Figure 2 As can be seen from the image, the drive sleeve 12 includes a polygonal periphery.

[0107] The drive sleeve 12 includes a shoulder 22 around which the aperture 23 of the actuator housing 18 surrounds the shoulder 22. The shoulder allows the drive sleeve 12 to be centered and guided within the actuator housing 18.

[0108] The stator 3 is received within a cylindrical cavity 19 having a closed base 20. Similarly, the rotor 4 is received within the cylindrical cavity 19. The cylindrical cavity 19 forms part of the lower housing 34.

[0109] Figure 5 The stator 3 is shown in detail. The stator 3 includes an electromagnetic coil 28 positioned on a printed circuit board 29. The current flowing in the electromagnetic coil 28 generates a magnetic field that can rotate the rotor 4. The printed circuit board 29 is positioned on a substrate 20 of a cylindrical cavity 19.

[0110] Actuator 50 includes connector 32. Connecting lugs (not shown) of connector 32 can control the flow of current in the coils of stator 3, thereby generating a magnetic field that interacts with the permanent magnet 27 of rotor 4.

[0111] Figure 6 and Figure 7 Details of rotor 4 are shown. Rotor 4 includes a cylindrical wall 24 extending along axis X and a flange 25 extending transversely to axis X. The cylindrical wall 24 of rotor 4 includes an inner surface 26 on which a magnet 27 is positioned. The permanent magnet 27 may, for example, be engaged to the inner surface 26 of rotor 4. The permanent magnet 27 may also be overmolded such that it is incorporated into the material of rotor 4. Flange 25 is disc-shaped. A pinion 5 rigidly connected to rotor 4 and magnet 27 are axially positioned on both sides of flange 25.

[0112] The rotor 4 includes a guide shaft 30 that inserts into a central hole 31 in the stator 3. The central hole 31 is formed in a stack of layers contained in the magnetic circuit of the stator 3. The guide shaft 30 includes a shoulder 36 that abuts against the periphery 37 of the central hole 31 in the stator 3. Therefore, the assembly of the rotor 4 in the stator 3 is simplified. The axial dimension of the electric motor 2 is reduced. The rotor 4 can be made of plastic or metal. The stator 3 includes at least three coils 38 arranged in a star configuration around the central hole 31. Figure 5 In the example shown, the stator includes six coils 28.

[0113] The present invention also relates to a heating, ventilation and / or air conditioning system for a motor vehicle, comprising at least one air flow duct and a movable baffle configured to control airflow in the duct, the baffle being configured to be driven by the electric actuator described above.

[0114] The specific arrangement of the electric motor 2 and the drive mechanism 6 allows for an actuator with an optimized magnetic circuit while maintaining a compact design. The compactness of the electric actuator 50 allows for easy integration into heating, ventilation, and / or air conditioning systems. Furthermore, the resulting high gear reduction ratio allows for significant force to be obtained while using a smaller electric motor. This limits the cost of the electric motor, and therefore the cost of the actuator.

[0115] Heating, ventilation and / or air conditioning systems typically include multiple electric actuators as described above, each actuator managing the position of an individual damper.

[0116] According to an embodiment not shown, the electric motor and the actuator incorporating the electric motor may further include one or more of the following features, considered individually or in combination:

[0117] The drive sleeve 12 may include splines.

[0118] The base 14 of the recess 13 of the drive sleeve 12 may include one or more openings.

[0119] The at least one planetary gear includes a first gear stage and a second gear stage rigidly connected to the first gear stage, the two gear stages being coaxial and capable of having the same diameter.

[0120] The electric actuator may include four planetary gears, each of which is translatably connected to the planet carrier and rotates freely relative to the planet carrier.

[0121] Of course, other modifications and variations will be apparent to those skilled in the art after examining the different embodiments described herein. The invention should not be limited to the embodiments described and illustrated in this application, which are given by way of example and are not intended to limit the scope of the invention.

Claims

1. An electric actuator (50) suitable for driving a movable element of a heating, ventilation and / or air conditioning system for a motor vehicle, said electric actuator comprising: Electric motor (2), comprising: Stator (3), The rotor (4) extends along the axis (X). A pinion (5) rigidly connected to the rotor (4), Drive mechanism (6), including: Planetary support (7), At least two planetary gears (8, 9) are held by the planet carrier (7), each planetary gear (8, 9) being translatably connected to the planet carrier (7) and freely rotatable relative to the planet carrier, the planetary gears (8, 9) being adapted to be rotated by the pinion (5). An output gear ring (11) adapted to be rotated by the at least one planetary gear (8), A drive sleeve (12) rigidly connected to the output gear ring (11) and adapted to drive the movable element, The drive sleeve (12) is at a certain distance from the electric motor (2) in the direction along the axis (X) of the rotor (4); The drive sleeve (12) is radially positioned between the axes of the planetary gears (8, 9).

2. The electric actuator according to claim 1, wherein, The pinion (5), which is rigidly connected to the rotor (4), faces the drive sleeve (12) in the axial direction.

3. The electric actuator according to claim 1 or 2, wherein, The drive sleeve (12) includes a recess (13) arranged to receive a protrusion of the movable element, the recess (13) being at least partially closed by a base (14), and wherein the pinion (5) rigidly connected to the rotor (4) faces the base (14) of the recess (13) of the drive sleeve (12).

4. The electric actuator according to any one of the preceding claims, wherein, The rotor (4) is outside the stator (3).

5. The electric actuator according to any one of the preceding claims, wherein, The at least one planetary gear (8) includes a first gear stage (15) and a second gear stage (16) rigidly connected to the first gear stage (15), the first gear stage (15) and the second gear stage (16) being coaxial and having different diameters (D1, D2).

6. The electric actuator according to claim 5, comprising an external gear ring (17) fixed relative to the stator (3), wherein, The first gear stage (15) is adapted to mesh with the external gear ring (17), and wherein the second gear stage (16) is adapted to mesh with the output gear ring (11).

7. The electric actuator according to any one of the preceding claims, wherein the rotor (4) comprises a cylindrical wall (24) extending along the axis (X) and a flange (25) extending transversely to the axis (X).

8. The electric actuator according to claim 7, wherein, The cylindrical wall (24) of the rotor (4) includes an inner surface (26) on which a magnet (27) is positioned, wherein the flange (25) is disc-shaped, and wherein the pinion (5) rigidly connected to the rotor (4) and the magnet (27) are axially positioned on both sides of the flange (25).

9. A heating, ventilation and / or air conditioning system for a motor vehicle, comprising at least one airflow duct and a movable baffle configured to control airflow in the duct, the baffle being configured to be driven by an electric actuator as described in any of the preceding claims.

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