NON-REVERSE COUPLING DEVICE WITH ACTIVE AERODYNAMICS

Description

FIELD OF THE INVENTION

[0001] The present invention relates to an active aerodynamic system comprising a deflector and being driven by an actuator with a non-back drivable cluthced module.BACKGROUND OF THE INVENTION

[0002] Design a device that can transfer a torque applied from the input drive to the output drive but not transfer torque from the output drive back to the input drive. The output drive should also be able to decouple itself from the input drive for large torque input to protect the system. Additionally, the device should also transfer output shaft vibration and impact loads to the device structure and not through the input drive, protecting the actuator. During an impact, the output shaft would decouple, once the load is removed, the device should return to a designated position through mechanical solutions and not require electrical position sensors.

[0003] US 2019 / 0010997 A1 discloses a torque limiting assembly comprising: an input shaft, an output shaft and spring having a first end coupled to the input shaft and a second end coupled with the output shaft. In a low torque mode, when the input shaft is rotated, the spring is compressed by a low amount and transmits a force to drive rotation of the output shaft, whereas in a high torque mode the spring is compressed by a high amount such that the input shaft rotates relative to the output shaft. This relative rotation moves or urges an engagement member so as to either disconnect the input shaft from the output shaft or engage a housing to prevent or inhibit rotation of the input shaft relative to the housing.

[0004] WO 2016 / 028196 A1 is a generically remote document which discloses a vibration absorber provided in a transmission path of a brush-cutter, including an input-side transmission shaft that receives the rotary driving force from the engine; an output-side transmission shaft that is disposed on the same axis as that of the input-side transmission shaft and is rotatable relative to the input-side transmission shaft to output the rotary driving force to the cutter blade; a bushing provided on the axis and is rotatable relative to the input-side transmission shaft and the output-side transmission shaft; a helical torsion coil spring disposed on the axis and having a first end attached to the bushing and a second end attached to the output-side transmission shaft; and a power transmission switching unit that switches a transmission state of the rotary driving force between the input-side transmission shaft and the bushing between a first state and a second state, the first state allowing the transmission of the rotary driving force so that the helical torsion coil spring is deformed in a diameter-reducing range, the second state restricting the transmission of the rotary driving force through the helical torsion coil spring.SUMMARY OF THE INVENTION

[0005] The present invention is directed to an active aerodynamic system with the features of claim 1. Embodiments thereof are defined in the

[0006] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. The detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention as defined by the appended claims.

[0007] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: Fig. 1 is an exploded isometric top view of a non-backdrivable clutched module for a bidirectional actuator. Fig. 2 is second exploded isometric top view of the non-backdrivable clutched module for a bidirectional actuator. FIG. 3 is a cross-sectional side isometric view of the non-back drivable clutched module. FIG. 4 is a cross-sectional side plan view of the non-back drivable clutched module. FIG. 5 is a side isometric view of a clutch cog according to the present invention. FIG. 6 is a side isometric view of a clutched output shaft with spring element connected according to the present invention. Fig. 7 is a side perspective view of a clutch cog connected to an actuator of a device. Fig. 8 is an overhead plan view of a clutch cog connected to an actuator of a device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Referring to the Figures, the present invention is directed to a non-backdrivable clutched module or module 10 for a bi-directional actuator. The module 10 includes a housing with a body piece 12 and a cover piece 11 each having mounting flanges 14, 14' to connect to the housing to the bi-directional actuator 13 that is external to the components of the module 10. While the module 10 is described as separate from the actuator 13, it is within the scope of this invention for the module to be integrated into an actuator 13. The body piece 12 includes an inside surface 16 that forms a cavity 18 for containing portions of the other components of the module 10.

[0009] Partially disposed in the cavity 18 of the housing 12 is an input shaft cog 20 with a shaft portion 22 extending out of the housing 12 and connected to the actuator 13 external to the housing 12. The input shaft cog 20 also has a cog portion 24 rotatably positioned in the housing 12. The cog portion 24 includes a plurality of bearing recesses 26, 28 and a plurality of drive recesses 30, 32 each having a first side 34a-d, second side 36a-d, third side 38 and fourth side 40a, 40b. The first side 34a-d and second side 36a-d of each of the plurality of bearing recesses 26, 28 and plurality of drive recesses 30, 32 are formed by one of a plurality of teeth 42, 42', 42", 42‴ extending from the surface of the cog portion 24 and the third side 38 is defined by the inside surface 16 of the housing 12.

[0010] The module 10 also has a clutched output shaft 44 having a shaft 46 portion extending out of the housing 12 and connected to a device 45 being driven by the actuator 13. As shown in Figs. 7 and 8 the device 45 being driven is an active aerodynamic system, more specifically an air dam and the shaft 46 connects to a torque transfer tube 43 that connects to a linkage 47 then moves a deflector 49 between a deployed position and undeployed position. While the device 45 is shown part of an active aerodynamic system it is within the scope of this invention for the module 10 to be used in any aerodynamic system where there is concern damage from back driving forces. Examples of devices include, moveable spoiler actuators, and active air dam actuators.

[0011] The clutched output shaft 44 also has a clutch cog receiving portion 48 rotatably positioned within the cavity 18 of the housing 12.

[0012] The module 10 further includes a clutch cog 50 positioned between the input shaft cog 20 and the clutched output shaft 44. The clutch cog 50 has both a resilient connection 52 and a detent connection with the clutch cog receiving portion 48 of the clutched output shaft 44. The resilient connection 52 is depicted as a spring that has a first end 58 that connects to a slot 60 in the clutch cog receiving portion 48 and a second end 62 that is connected to a hole 64 in the clutch cog 50. The type of spring used can vary depending on the particular application. In the current embodiment of the invention the spring is a coil spring. However, it is within the scope of the invention for other springs to be used such as wave spring, coil spring and combinations thereof. The detent connection is provided by detent projections 66 on the clutch cog 50 that engage detent recesses 68 formed on the surface of the thereof. The detent connection is provided by detent projections 66 on the clutch cog 50 that engage detent recesses 68 formed on the surface of the clutch cog 50 receiving portion 48 of the clutched output shaft 44. The clutch cog 50 also includes a plurality of teeth 70, 70' of the clutch cog 50. Each one of the plurality of teeth 70, 70' are configured to mate with and engage one of the plurality of drive recesses 30, 32 of the input shaft cog 20. When the input shaft cog 20 rotates in response to torque from the actuator through the shaft portion 22, the plurality of teeth 42, 42', 42", 42‴ of the input shaft cog 20 will press against the plurality of teeth 70, 70' to transfer rotational force that gets transmitted to the clutched output shaft 44.

[0013] A plurality of flat surfaces 72, 72' of the clutch cog 50 also had a plurality of flat surfaces 72, 72' configured to form the fourth side 40a, 40b of a respective one of the plurality of bearing recesses 26, 28. A bearing 74, 74' is positioned in each one of the plurality of bearing recesses 26,28. The figures depicts a ball bearing however, it is within the scope of this invention for the bearing 74, 74' to be a different type of bearing such as a cylindrical roller bearing, conical bearing or double end tapered bearing.

[0014] The module 10 has a stopper mode and a clutch mode. The stopper mode occurs where upon a first back drive force being applied to the clutched output shaft 44. The clutch cog 50 is stopped from transmitting backdriving force to the actuator through the input shaft cog 20. This happens by forces acting on the clutched output shaft 44 rotating the clutched cog 50 so that the plurality of teeth 70, 70' of the clutch cog 50 rotate away and disengage the plurality of teeth 42, 42', 42", 42‴ of the input shaft cog 20. During this rotational movement the plurality of flat surfaces 72, 72' forming the fourth wall 40a, 40b of the respective plurality of bearing recesses 26, 28, act against the bearing 74, 74' in the respective bearing stop recess 26, 28 so that each bearing 74, 74' in the plurality of bearing recesses 26, 28 is locked between the fourth wall 40a, 40b and the third wall 38, which is the inside surface 16 of the housing 12, thereby preventing the back drive force from being transmitted to the input shaft cog 20. Thus, the back-driving force is diverted away from the input shaft cog 20 to the housing 12, which prevents the actuator from back driving and acts to stop or hold the clutched output shaft 44 in place.

[0015] The input shaft cog 20 and clutched output shaft 44 have geometry that allow for a friction locking when the torque is applied from the input shaft cog 20. The friction force is generated between the output shaft cog and the bearing which can be a cylinder, sphere, conical roller, sprocket or other suitable element that gets locked up against the inside surface or outer race wall of the housing. Once the friction force is equal to the normal force between the output shaft cog generated by the angle produced during the rotation caused by the applied torque, the system is unable to be back driven. Geometry on the input shaft cog does not allow the cylinder to create such friction forces on the outer race and thus transfers the torque to the output shaft. Various shapes and springs can be used to tune performance such as to limit the free play or backlash of the system or to tune the engagement timing of the various functions.

[0016] However, if the second driving force that is greater than the first back driving force acts on the clutched output shaft 44 is too great, the module 10 has a clutch mode. Clutch mode will occur when the second back drive force connection between the clutched output shaft and clutch cog and the clutched output shaft will move freely against the force of the resilient connection, wherein upon cessation of the second back drive force the resilient connection causes the detent connection to reengage.

Claims

1. An active aerodynamic system (45) comprising a deflector (49) and being driven by a bi-directional actuator (13) with a non-back drivable clutched module (10) between a deployed position and an undeployed position, the non-back drivable clutched module (10) comprising: a housing (12) with an inside surface (16) defining a cavity (18); an input shaft cog (20) with a shaft portion (22) extending out of the housing (12) and connected to an external actuator (13), and a cog portion (24) rotatably positioned in the cavity (18) of the housing (12), wherein the cog portion (24) includes a plurality of bearing recesses (26, 28) and a plurality of drive recesses (30, 32) each having a first side (34a-d), second side (36a-d), third side (38) and a fourth side (40a, 40b), where the first side (34a-d) and second side (36a-d) are each formed by one of a plurality of teeth (42, 42', 42", 42‴) extending from the surface of the cog portion (24) and the third side (38) is defined by the inside surface (16) of the cavity (18) of the housing (12); a clutched output shaft (44) having a shaft portion (46) extending out of the housing (12) and connected to the active aerodynamic system (45) being driven by the actuator (13) through the non-back drivable clutched module (10) and a clutch cog receiving portion (48) rotatably positioned within the cavity (18) of the housing (12); a clutch cog (50) between the input shaft cog (20) and the clutched output shaft (44), where the clutch cog (50) has both a resilient connection (52) and a detent connection (66, 68) to the clutched output shaft (44).

2. The active aerodynamic system (45) of claim 1, further comprising: a plurality of teeth (70, 70') of the clutch cog (50), where each one of the plurality of teeth (70, 70') are configured to mate with and engage one of the plurality of drive recesses (30, 32) of the input shaft cog (20).

3. The active aerodynamic system (45) of claim 1 or 2, further comprising: a plurality of flat surfaces (72, 72') of the clutch cog (50) configured to form the fourth side (40a, 40b) of a respective one of the plurality of bearing recesses (26, 28), and a bearing (74, 74') positioned in each one of the plurality of bearing recesses (26, 28).

4. The active aerodynamic system (45) of claim 3, further comprising: a stopper mode of the non-back drivable clutched module (10) wherein upon a first back drive force being applied to the clutched output shaft (44), the clutch cog (50) is stopped from transmitting back driving force to the actuator (13) through the input shaft cog (20) by moving the plurality of flat surfaces (72, 72') forming the fourth wall (40a, 40b) of the respective plurality of bearing recesses (26, 28) so that each bearing (74, 74') in the plurality of bearing recesses (26, 28) is locked between the fourth wall (40a, 40b) and the third wall (38), which is the inside surface (16) of the housing (12), thereby preventing the back drive force from being transmitted to the input shaft cog (20).

5. The active aerodynamic system (45) of claim 4, further comprising: a clutch mode where upon a second back drive force greater than the first back drive force and the second back drive force being sufficient enough to overcome the resilient connection (52) between the clutched output shaft (44) and the clutch cog (50), the clutched output shaft (44) will disengage the detent connection (66, 68) between the clutched output shaft (44) and clutch cog (50) and the clutched output shaft (44) will move freely against the force of the resilient connection (52), wherein upon cessation of the second back drive force the resilient connection (52) causes the detent connection (66, 68) to reengage.

6. The active aerodynamic system (45) of any one of claims 1 to 3, wherein the clutch cog (50) has a clutch mode that disengages the clutch cog (50) from the clutched output shaft (44) and a stopper mode where the clutch cog (50) acts on at least one bearing member (74, 74') between the clutch cog (50) and the housing (12) and locks the clutch cog (50) to prevent the clutch cog (50) from moving the input shaft cog (20).

7. The active aerodynamic system (45) of claim 6, wherein the clutch mode further includes where upon a second back drive force greater than the first back drive force and the second back drive force being sufficient enough to overcome the resilient connection (52) between the clutched output shaft (44) and the clutch cog (50), the clutched output shaft (44) will disengage the detent connection (66, 68) between the clutched output shaft (44) and clutch cog (50) and the clutched output shaft (44) will move freely against the force of the resilient connection (52), wherein upon cessation of the second back drive force the resilient connection (52) causes the detent connection (66, 68) to reengage.

8. The active aerodynamic system (45) of any one of claims 1 to 7, wherein the at least one bearing member (74, 74') is a ball bearing, roller bearing, conical bearing.

9. The active aerodynamic system (45) of any one of claims 1 to 8, wherein the resilient member (52) is a coil spring having a first end connected to the clutch cog (50) and a second end connected to the clutched output shaft (44).

10. The active aerodynamic system (45) of any one of claims 1 to 9, wherein the resilient member (52) is one selected from the group comprising wave spring, coil spring and combinations thereof.

11. The active aerodynamic system (45) of any one of claims 1 to 10, which is one selected from the group consisting of moveable spoiler actuators and active air dam actuators.