The present invention relates to a powered actuating device for a closure panel of a vehicle, such as a hood or a rear lift gate for a trunk, to which the following description refers purely by way of example.

As is known, vehicles normally have a rear access opening to a luggage compartment, and a door assembly for closing the access opening.

More specifically, door assemblies are known, as described for example in Patent US6516567, comprising a lift gate hinged to a fixed horizontal axis of the vehicle; one or more actuating devices interposed between the lift gate and a rear portion of the vehicle body distinct from said axis and delimiting the luggage compartment; and a motor for selectively controlling the actuating devices.

Known door assemblies can normally be set to a first and second operating configuration, in which the rear access opening of the vehicle is fully open and closed respectively.

More specifically, when the door assembly is in the fully-open configuration, the lift gate is detached from the rear portion of the vehicle body and fully raised with respect to its hinge axis so that the access opening is completely clear; and, in the closed configuration, the lift gate is lowered with respect to its hinge axis, and rests against the rear portion of the vehicle body defining the access opening to the luggage compartment, so that the access opening is fully closed.

Known door assembly actuating devices each comprise a telescopic arm and a gas spring, which are interposed between, and connected to separate parts of, the lift gate and the rear portion of the vehicle body, so as to extend side by side. More specifically, the telescopic arm comprises a first and second member fixed to the rear portion of the vehicle body and to the lift gate respectively, and provides for moving the door assembly from one operating configuration to the other.

The first member of the telescopic arm is fitted with a screw connected functionally to the motor, and the second member is fitted with a nut screw integral with the lift gate and connected to the screw to permit slide of the second member with respect to the first member and extension/contraction of the telescopic arm.

The door assembly is moved from the closed to the open configuration by

operating the motor in a first rotation direction.

The motor rotates the screw on the first member, so that the nut screw translates with respect to the screw in such a direction as to move the second member away from the first member and so extend the telescopic arm. The lift gate, hinged to the fixed axis of the vehicle and connected to the second member of the telescopic arm, is therefore raised with respect to its hinge axis to move the door assembly into the fully-open configuration.

The door assembly is moved from the fully-open to the closed configuration in the same way, by operating the motor in a second rotation direction to contract the telescopic arm.

Contraction of the telescopic arm lowers the lift gate with respect to its hinge axis, so as to move the door assembly into the closed configuration.

The gas spring provides for maintaining equilibrium of the lift gate, when the motor is deactivated and the door assembly is in the fully-open configuration, by counteracting the weight of the lift gate.

Operation of the telescopic arm, in fact, requires that the screw and nut screw be connected reversibly, which means provision must be made to prevent the lift gate being lowered with respect to its hinge axis under its own weight when the motor is deactivated. Known actuating devices require separate attachment points for the gas spring and the telescopic arm.

As a result, known devices are bulky, and limit access to the luggage compartment when loading large-size objects.

It is an object of the present invention to provide a powered actuating device for a closure panel of a vehicle, designed to eliminate the aforementioned drawback typically associated with known devices.

According to the present invention, there is provided a powered actuating device for a closure panel of a vehicle, as claimed in Claim 1.

A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a rear view in perspective of a vehicle comprising two lift gate actuating devices in accordance with the present invention;

Figures 2 and 3 show enlarged axial sections of one of the Figure 1 actuating devices in two different operating positions.

Number 1 in Figure 1 indicates as a whole a door assembly for closing an access opening 2 to a rear luggage compartment 3 of a vehicle 4. Assembly 1 can be set to two distinct operating configurations fully opening

(Figure 1) and fully closing access opening 2, and substantially comprises a lift gate 5 hinged about a horizontal axis A to one end 7 of the body of vehicle 4; one or more devices 6 - two in the example shown - interposed between end 7 and lift gate 5 to move lift gate 5 into said operating configurations; and a known motor 11 for selectively controlling devices 6.

In the fully-open configuration (Figure 1) of assembly 1, lift gate 5 is detached from end 7 and raised with respect to axis A, so that access opening 2 is completely clear; and, in the fully-closed configuration (not shown) of assembly 1, lift gate 5 is lowered with respect to axis A and rests against end 7, so that access opening 2 is closed completely.

Each device 6 substantially comprises a telescopic arm 10 powered by motor 11 to move lift gate 5 into the operating configurations of assembly 1; and a gas spring 12 for maintaining equilibrium of lift gate 5 in the open configuration.

With particular reference to Figures 2 and 3, each telescopic arm 10 has an axis B, and comprises two hollow members 13, 14 connected in axially-sliding manner to each other, and integral with end 7 of the body of vehicle 4 and with lift gate 5 respectively.

More specifically, member 14 is located radially inwards of member 13, and is slidable axially with respect to member 13 to vary the length of telescopic arm 10, as described in detail later on.

Member 13 substantially comprises a hollow, substantially cylindrical casing 15 fixed to end 7 of the body of vehicle 4; and a screw 17 powered by motor 11, as described in detail later on, housed inside casing 15, and engaging a nut screw 16 formed on member 14. More specifically, casing 15 has a closed first axial end 18 fixed to end 7 of the body of vehicle 4; and a cylindrical tubular portion 19 housing screw 17 and defining an open axial end 20, opposite end 18, for connection to member 14.

Screw 17 comprises a substantially cylindrical stem 26 housed loosely inside tubular portion 19 of casing 15, and having a threaded outer surface 33 engaging nut screw 16; and a smaller-diameter end portion 25, which is supported in axially fixed and rotary manner by an inner annular rib of tubular portion 19, and is driven by motor 11 as described in detail later on.

More specifically, stem 26 of screw 17 and tubular portion 19 of casing 15 define between them an annular-section cylindrical seat 27 for receiving member 14.

Member 14 is defined by a hollow, substantially cylindrical casing 29 comprising a closed first end 30 fixed to lift gate 5, and an open second end 31, opposite end 30, having a radially inner, threaded surface 32.

More specifically, end 31 of member 14 engages seat 27, and is interposed between tubular portion 19 of casing 15 and stem 26 of screw 17, so that threaded surfaces 32 and 33 engage mutually.

The threads of threaded surfaces 32 and 33 are shaped and proportioned in known manner to permit reversible relative motion between stem 26 of screw 17 and end 31 of member 14.

According to an important aspect of the present invention, gas spring 12 is housed inside telescopic arm 10 and connected to members 13 and 14.

Advantageously, screw 17 defines an axial through cavity, and spring 12 comprises a hollow cylindrical jacket 35 containing gas, fitted inside stem 26 of screw 17, and fixed to screw 17; and a plunger 36 sliding in fluidtight manner inside jacket 35 and connected to casing 29 of member 14.

More specifically, jacket 35 comprises a cylindrical tubular wall 35a; and opposite ends 35b, 35c, from one of which (35b), facing end 18, a pin 38 projects axially and is connected prismatically to end portion 25 to connect screw 17 and jacket 35 angularly integral with each other.

Plunger 36 comprises a piston 40 sliding in fluidtight manner along the inner wall of jacket 35; and a smaller-diameter rod 39 projecting from piston 40, extending in fluidtight manner through end 35c, and having one end, opposite piston 40, connected to casing 29, close to end 30.

Piston 40 divides jacket 35 into two separate chambers 41, 42, each bounded by piston 40 and a relative end 35b, 35c; and piston 40 has at least one hole 43

permitting two-way gas flow between chambers 41, 42.

Motor 11 and each device 6 are connected functionally by means of a transmission 34 comprising a flexible connecting member, e.g. a flexible Bowden cable, and a known reducer 24 not shown in detail. In a preferred embodiment of the present invention, reducer 24 is housed at least partly inside casing 15 of member 13, and has an input shaft (not shown) connected by flexible cable 37 to motor 11, and an output shaft 21 connected to screw 17.

More specifically, reducer 24 is housed inside a cylindrical seat 28 having an axis C perpendicular to axis B and formed inside casing 15, close to end 18; and output shaft 21 extends coaxially with axis B and is fitted prismatically inside end portion 25 of screw 17.

Flexible cable 37 comprises a sheath 22 fixed at opposite ends to the fixed external parts of motor 11 and reducer 24 respectively; and a core 23 rotatable inside sheath 22 and connected functionally to an output member (not shown) of motor 11 and to the input shaft of reducer 24.

In actual use, on the basis of a user command, assembly 1 is moved selectively by devices 6 between the closed and fully-open operating configurations and vice versa. The fully-open configuration of assembly 1 (Figures 1 and 2) corresponds to a maximum length of arm 10 produced by maximum axial projection of member 14 with respect to member 13; and the closed configuration (Figure 3) of assembly 1 corresponds to a minimum length of arm 10 and therefore minimum axial projection of member 14 with respect to member 13. More specifically, as of the closed configuration (Figure 3), motor 11, on receiving an appropriate control signal, is rotated in a first direction, and in turn rotates screws 17 of respective devices 6 about respective axes B by means of flexible cables 37 and reducers 24.

Rotation of each screw 17 translates casing 29 of member 14 along axis B by means of the connection between threaded surfaces 33 and 32.

Translation of casing 29 moves end 30, integral with lift gate 5, away from end 18 of casing 15 connected to end 7 of the body of vehicle 4.

As a result, member 14 slides inside member 13 to increase the free length of telescopic arm 10 and the extension of the portion of member 13 projecting from member 14.

Consequently, lift gate 5, hinged about axis A to end 7 of the body of vehicle 4 and connected to member 14, is raised with respect to axis A.

At the same time, jacket 35 of spring 12 is rotated integrally with screw 17 by means of the prismatic connection between end portion 25 and pin 38.

As member 14 slides inside member 13, piston 40, connected to casing 29 of member 14, slides axially inside jacket 35, connected to member 13, towards end 30 to extend spring 12.

At this stage, gas flows from chamber 42 to chamber 41 through hole 43 in piston 40 until a condition of equilibrium is established.

On reaching the maximum length of telescopic arm 10 and maximum projection of member 14 from member 13, assembly 1 assumes the fully-open configuration, lift gate 5 is raised completely with respect to axis A, and motor 11 is deactivated.

In this condition, spring 12 maintains lift gate 5 in equilibrium, to prevent the weight of the lift gate from translating casing 29 and so rotating screw 17.

Assembly 1 is moved from the fully-open to the closed configuration in exactly the same way as described above, except that motor 11 is rotated, by means of an appropriate control signal, in a second direction opposite the first, and, at the end of the operation, spring 12 assumes a shortened configuration produced by gas flowing from chamber 41 to chamber 42 through hole 43 in piston 40.

Given the reversibility of the connection between threaded surfaces 32 and 33 of nut screw 16 and screw 17, assembly 1 can also be set to the closed or open configuration without operating motor 11, and by simply acting manually on lift gate 5 to position it resting against or detached from end 7 of the body of vehicle 4 respectively. For which purpose, a known clutch (not shown) is conveniently interposed between motor 11 and transmission 34. The advantages of actuating devices 6 according to the present invention will be clear from the foregoing description.

In particular, devices 6 provide for both moving and sustaining lift gate 5 in

the open position, while only occupying the same overall space as known telescopic arms.

Moreover, devices 6 do not require separate attachment points for springs 12 and telescopic arms 10, thus simplifying use of access opening 2 to luggage compartment 3 and assembly of devices 6 themselves. More specifically, on-vehicle integration cost of gas springs 12 and telescopic arms 10 is much cheaper as compared with that of known devices.

Clearly, changes may be made to actuating devices 6 as described and illustrated herein without, however, departing from the protective scope defined in the accompanying Claims.

In particular, spring 12 may employ air or other types of fluid, or may be replaced by any other type of elastic means, i.e. capable of an elastic variation in length.

Moreover, reducer 24 may be housed inside casing 15 of member 13 and extend coaxially with axis B .

Finally, actuating devices 6 as described and claimed herein may be advantageously used on vehicle closure panels of different type, such as hoods.