Actuated element assembly

ACTUATED ELEMENT ASSEMBLY

Field of the invention

The present invention generally relates to an actuated element assembly. Background of the invention

Such an actuated element assembly is typically found in a car's Heating, Ventilation and Air Conditioning module (or HVAC module), the module which allows to control air flow and temperature within the car.

An HVAC module generally takes the form of a casing, which is connected to a fresh air inlet and which comprises the various elements needed to control air temperature and air flow, such as e.g. regulating electronics, blower motor, fan, heater, etc. The HVAC module is further connected to air ducts leading to air nozzles in the car. Dispatching of heated or cooled air between the various air ducts is achieved by means of pivotable flaps mounted in the casing.

Typically such flaps comprise two shaft portions which are rotatably supported in plain bearings in the walls of the casing. Actuation of a flap is carried out by means of an actuator having an output shaft that is inserted into a recess in one of the shaft portions from the outside of the casing, the output shaft and the recess in the shaft portion having interlocking shapes so as to obtain a rotational coupling. The actuator is further provided with e.g. two fixing tabs, which are to be aligned with two stays on the casing and screwed thereto in order to fix the actuator to the casing.

A disadvantage of such a structure is that its assembly is difficult, in particular when the dimensional tolerances of the various elements are not close enough. Indeed, the output shaft of the actuator must be aligned with the cavity in the shaft portion of the flap, while it is also necessary to align the fixing tabs with the stocks so as to fix the actuator. However, it often happens that once the output shaft has been inserted into the shaft portion of the flap, the tabs are not properly aligned with the stocks on the casing.

Object of the invention

The object of the invention is to provide a simpler assembly for an actuatable element, in which alignment problems are alleviated. This object is achieved by an actuated element assembly as claimed in claim 1.

Summary of the invention

An actuated element assembly in accordance with the invention comprises an actuatable element mounted in a casing, the actuatable element comprising a first shaft portion rotatably mounted in the casing and a second shaft portion. The casing has an opening essentially coaxial with a central axis of the second shaft portion. The assembly further includes an actuator having a housing, in which an output shaft is rotatably mounted, for actuating the actuatable element. The actuator is mounted on the casing in such a way that the second shaft portion and the output shaft are coupled together and that the second shaft portion is supported by the output shaft.

In the assembly of the invention, the shaft portion of the actuatable element, which is coupled to the output shaft of the actuator is thus also supported by the latter, whereas in conventional structures this shaft portion of the actuatable element is individually supported in a bearing in the casing wall. The suppression of this bearing simplifies the structure of the assembly, which also means a simplified assembly process and reduced manufacturing costs. Moreover, as the shaft portion which is to be coupled to the actuator output shaft is not maintained in a bearing in the casing wall, it can be more easily aligned with the output shaft of the actuator. The mounting of the actuator to the casing is thus simplified, and the range of dimensional tolerance of the various elements of the assembly can be wider.

As mentioned above, the output shaft of the actuator achieves a double function which is to support and actuate the actuatable element. One way of doing this is by rigidly joining the output shaft and shaft portion by means of e.g.

a coupling element. It is also possible to arrange a recess in the shaft portion, in which the output shaft can be inserted. However, the output shaft is preferably configured in such a way that the second shaft portion is at least partially received in the output shaft.

It is clear that in the present assembly, the actuator should preferably be fixed to the casing. The latter is thus advantageously provided with first fixing means and the actuator with cooperating second fixing means. Preferably the cooperating first and second fixing means are configured in such a way as to provide a fast-locking means, such as e.g. a twist-lock or a snap-fit, which simplifies the fixing of the actuator to the casing.

Referring more particularly to the actuator, the output shaft is preferably supported in a sleeve, the sleeve having an inner end fixedly connected to the actuator and an outer end extending towards the casing. In such a case, the first fixing means may be advantageously provided about the opening in the casing and the second fixing means about the sleeve.

Preferably, the fast-locking means is a twist-lock. In a preferred embodiment, in order to mount the actuator to the casing by means of a twist-lock, at least one radially extending gap is provided in the casing at the periphery of the opening. Moreover, the sleeve of the actuator is provided at its outer end with a radially projecting element dimensioned to be inserted through the gap in the casing and locked behind the casing wall by rotation of the actuator. This allows for an easy mounting of the actuator to the casing, without screws or any other additional fixing elements.

For limiting air leakage, the assembly is advantageously provided with sealing means that surround the opening in the casing and extend between the casing and the actuator. Such sealing means may comprise a protruding annular lip on the casing, which bears against a cooperating sealing surface of the actuator. Alternatively, the sealing means may comprise a protruding annular lip on the actuator, which bears against the casing. Furthermore, the annular lip may be replaced by an O-ring. It is to be noted that such sealing means, sandwiched between casing and actuator, also provide a kind of spring tension, which increases the robustness of the formerly described twist-lock.

Generally, the actuator will be connected to a control unit, which will activate the actuator when an actuation of the actuatable element is desired. Connection of the actuator to the wire network of the control unit may be done by means of plug and socket. This kind of connection however has the drawback that a plug may be inserted into the wrong socket. In order to avoid such connection errors, it is possible to use differing plug/socket sets for each element that is to be connected to the control unit. This would however increase manufacturing costs.

A preferred way of achieving this connection is to use, instead of the conventional wire bunch ending with a plug, a flexible printed circuit attached to the casing surface and to provide the actuator with contact terminals. The flexible printed circuit comprises conductive tracks which face the actuator. In this case, the flexible printed circuit and the terminals should be arranged in such a way that, by fixing the actuator to the casing, the contact terminals come into contact with the conductive tracks of the flexible printed circuit. The actuator is thus automatically connected to the control unit once mounted to the casing. Moreover, this avoids connection errors during assembly, since the electrical network formed by the flexible printed circuit is already at the right place before the actuator is mounted. In case the actuator is provided with a twist-lock, the contact terminals should of course be arranged on the actuator in such a way as to come into contact with the conductive tracks of the flexible printed circuit after activation of the twist lock, i.e. after rotation of the actuator into a locked position.

It is further to be noted that some of the tracks of the flexible printed circuit may be used for a binary coding of the actuator, in case a number of actuators are mounted to the casing. This is particularly interesting for control units using a bus system for individually controlling the different actuators. When wire bunches and plugs are used, if no precautions are taken, connection errors may arise during assembly. When using flexible printed circuits, the connection network is already at the correct location before the actuators are mounted.

Moreover, when some of the tracks are used for codification, the actuator is automatically connected and given a codified identification as a result of assembly.

Brief description of the drawings

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Fig.1: is a sectional view through a preferred embodiment of an assembly in accordance with the invention, wherein an actuator is mounted onto a casing;

Fig.2: is a partial three-dimensional view of the casing in the vicinity of the opening; and

Fig.3: is a three-dimensional view of the actuator of Fig.1.

In the Figures, same reference numbers indicate similar or identical elements.

Detailed description of a preferred embodiment A preferred embodiment of an assembly 10 in accordance with the invention is shown in sectional view in Fig.1. Reference sign 12 indicates a casing wall, having an inner side 14 and an outer side 16. This casing may e.g. be that of a heating, ventilation and air conditioning module, within which a flap is mounted. Such a flap has two shaft portions, a first (not shown) of these shaft portions being rotatably mounted in the casing wall. The second shaft portion, indicated 18 in Fig.2 (the second shaft portion 18 is not shown in Fig.1), is coaxially aligned with an opening 19 in the casing wall 12. In order to actuate this flap, an actuator 20 is mounted onto the casing wall 12. This actuator 20 has an actuator housing 22, in which an output shaft 24 is rotatably mounted. The output shaft 24 is supported in a sleeve 26 of the actuator 20, which has an inner end 28 integral with the actuator housing 22 and an outer end 30 towards the casing. Within the actuator housing 22, the output shaft 24 is coupled to a motor 32 by means of a reducing gear system comprising a gearwheel 34 integral with the output shaft 24 and two other gearwheels 36.

It shall be appreciated that the actuator 20 is mounted onto the casing wall 12 in such a way that the second shaft portion 18 of the flap is supported by the output shaft 24. In the present embodiment, the second shaft portion 18 is received in a recess 38 in the output shaft 24. Moreover, as can be seen on Fig.2, the end 40 of the second shaft portion 18 has a profiled outer shape with a flat part 42 for orientation. The recess 38 in the output shaft 24 has a similar inner shape, whereby the second shaft portion 18 of the flap and the output shaft 24 of the actuator 20 are rotationally coupled together. The actuator 20 used in the present assembly 10 thus allows to support and actuate the flap located within the casing from the exterior thereof.

In the present embodiment, the actuator is advantageously fixed to the casing wall 12 by means of a twist-lock, which allows a rapid and easy fixation of the actuator 20. Therefore, the opening 19 in the casing wall 12 has three equally spaced peripheral gaps 44, 44' and 44", which extend radially from the periphery of the opening 19, as shown in Fig.2. As for the actuator 20, the output shaft 24 is provided at its outer end 30 with three radially extending ribs 46, 46' and 46". These ribs 46, 46' and 46"are equally spaced at the periphery of the sleeve 26 and are dimensioned so as to be inserted through the gaps 44, 44' and 44" and locked behind the casing wall 12 by rotation of the actuator 20.

For securing the actuator 20 in a locked position, the actuator 20 is advantageously provided with a tab 48, which cooperates with a sliding bar 50 on the casing wall 12. At one of its ends, the sliding bar 50 is provided with a notch 52. When mounting the actuator 20 onto the casing wall 12, the actuator 20 is positioned in such a way that the second shaft portion 18 can be received into the output shaft 24, that the ribs 46, 46' and 46" are aligned with the gaps 44, 44' and 44" in the opening 19, and that the tab 48 is located towards the end of the sliding bar 50 opposite the notch 52. This is approximately the configuration shown in Fig.2. The actuator 20 is then assembled to the casing wall 12 and locked therein by introducing the ribs 46, 46' and 46" of the output shaft 24 into the casing through the gaps 44, 44' and 44", and rotating the actuator 20. The actuator is rotated in a counter clockwise direction so that when the ribs 46, 46' and 46" are locked behind the casing wall 12 next to the gaps 44, 44' and 44", the actuator tab 48 is locked into the notch 52 in the sliding bar 50. The result of this assembly is shown in Fig.1.

It is to be noted that the actuator 20 is very easily mounted to the casing wall, without problems of alignment. Indeed, since in the present embodiment, the fixing means of the actuator 20 are provided about the opening 19 and about the output shaft 24, aligning the second shaft portion 18 with the output shaft 24 automatically leads to the alignment of the fixing means.

Reference sign 54 in Figs.1 and 2 indicates an annular lip surrounding the opening 19 and extending between the casing wall 12 and the actuator 20. This annular lip 54 bears against a conical sealing surface 56 of the actuator 20, which surrounds the sleeve 26. This structure allows an essentially airtight mounting of the actuator 20 to the casing wall 12. Moreover, it provides some kind of elasticity, which increases the robustness of the twist-lock.

Turning again to Fig.2, reference sign 56 indicates a flexible printed circuit attached to the outer side 16 of the casing wall 12 and having conductive tracks 58 facing the actuator 20. This flexible printed circuit 56 is used instead of a conventional wire bunch ending by a plug for connecting the actuator e.g. to the regulating electronics of the HVAC module. As shown in Fig.3, the actuator 20 is provided with a series of contact terminals 60 (one for each track) arranged on the side of the actuator 20 facing the casing wall 12. These contact terminals 60 are connected to a printed circuit board inside the actuator housing 22. The flexible printed circuit 56 and the contact terminals 60 are arranged in such a way that, when the actuator 20 is locked in the opening 19 in the casing wall 12, each contact terminal 60 is in contact with its corresponding conductive track 58. The electrical connection of the actuator 20 thus automatically results from the mounting of the actuator 20 to the casing wall 12.

Although not shown in the Figures, the flexible printed circuit 56 may comprise a number of holes, which cooperate with moulded pins protruding on the outer sides of the casing for attaching the flexible printed circuit 56.

It is to be noted that an HVAC module is generally provided with a number of actuators. In such a case, there must be a way of identifying the different actuators, so that the regulating electronics can actuate them individually. The above described connection means proves very advantageous to achieve this. The flexible printed circuit extends over the whole casing to connect the different actuators. Where a bus system is employed for controlling the actuators, it is possible to use e.g. three tracks of the flexible printed circuit for a binary coding of the actuators. By mounting each actuator to the casing, the former would automatically be given an identification code.

In case conventional connection means, i.e. wire bunches and plugs, are used instead of such a flexible printed circuit, it is however still possible to achieve a coding of the actuators for bus systems. A number of pins could be formed on the casing in such a way as to break some circuits on the printed circuit board inside the actuator, when the latter is mounted to the casing.

Although in the above described embodiment the actuatable element is a flap, it is clear that the present assembly may be adapted for actuating a variety of actuatable elements mounted within a casing.