WO2012085416A1

WO2012085416A1 - Improvement in the sealing of an electromechanical device and actuator benefiting from this improvement

Info

Publication number: WO2012085416A1
Application number: PCT/FR2011/053032
Authority: WO
Inventors: Danilo Falchi; Dominique Dupuis
Original assignee: Valeo Systemes De Controle Moteur
Priority date: 2010-12-22
Filing date: 2011-12-16
Publication date: 2012-06-28
Also published as: FR2970371B1; FR2970371A1

Abstract

The invention relates to a device having a casing (9), an electronic control circuit (14) for the device, produced on at least one support (15) fixed to the device, and a cover (40) intended to protect said electronic circuit (14), characterized in that the support (15) of the electronic circuit (14) has a face (50) for fixing to the casing (9), comprising first sealing means (54) and a cover face (47) opposite the fixing face (50) and intended to receive the cover (40), the cover face (47) comprising second sealing means (51).

Description

Improved sealing of an electromechanical device and actuator benefiting from this

improvement

BACKGROUND OF THE INVENTION

The invention relates to the production of electromechanical actuators and in particular the protection of these actuators in severe environments.

The most common motorization systems generally comprise an internal combustion engine comprising an engine block delimiting combustion chambers having one end closed by a cylinder head and an opposite end closed by a piston slidably received in the engine block. The pistons are connected by a connecting rod to a crankshaft arranged to convert the reciprocating sliding movement of the pistons into a continuous rotational movement communicated to the driving wheels of the vehicle via the clutch and the gearbox. The cylinder head includes connecting pipes of the combustion chambers to an air supply circuit and a exhaust gas exhaust system. In four-stroke thermal engines, these connecting means comprise valves movable between a closed position of the ducts and an open position of the ducts.

In order to optimize the efficiency of the engine, the purely mechanical members, such as the camshaft for actuating the valves, are frequently replaced by electromagnetic actuators controlled by an electronic circuit. These electronic circuits are located closer to the actuators to limit the cables between the control members and the actuators.

The actuators are controlled by an electronic control circuit integrating a calculation electronics, a power electronics, sensors, interfaces ... Thus, the circuits, which are made on a flat rigid support, can be bulky and occupy an important place given the integrated functions. To protect them, in particular from the surrounding oil, rollovers are conventionally made bearing on the housing and completely covering the electronic circuit.

When the electronic circuit is in several parts distributed over several sides of the housing, the cowling then comprises several covers. It is then very difficult to achieve a seal when several parts are in contact.

The protection of the electronic circuits therefore involves producing on the casing of the actuator machining for fixing the cowling and machining allowing the establishment of sealing means. All these machining prove to be numerous and difficult to achieve, so expensive.

In addition, the housing face must be large enough to accommodate the electronic circuits and the cowling, which involves making either a larger housing or a smaller body.

The proposed invention simplifies the production of organs while allowing optimal use of the housing surface.

OBJECT OF THE INVENTION

The invention relates to a device comprising a housing, an electronic control circuit of the device made on at least one support fixed to the device and a cover for protecting said electronic circuit, characterized in that the support of the electronic circuit comprises a face of fixing on the housing comprising first sealing means and a cowling face, opposite to the fixing face and intended to receive the cowling, the cowling face comprising second sealing means. The sealing means are carried on a single piece, which facilitates the manufacture and assembly of the device.

Advantageously, the support of the electronic circuit comprises a lateral face adjacent to the fastening and cowling faces and comprising third sealing means arranged so that the sealing means of the fixing, cowling and lateral faces form a sealing bead. continued.

The first and second sealing means are joined by a third sealing means to form a continuous sealing bead isolating the electronic circuit and allowing the use of a complex angle-shaped cowling.

BRIEF DESCRIPTION OF THE INVENTION

Reference will be made to the appended drawings, among which:

Figure 1 is a perspective view of a motorization system;

- Figure 2 is a perspective view of an actuator, shown in Figure 1 without its cowling;

- Figure 3 is a perspective view of an actuator, shown in Figure 1 with its cowling according to a first embodiment of the invention;

- Figures 4 and 4a respectively illustrate an actuator with a portion of said cowling, a complementary portion of the cowling being removed from the actuator;

FIG. 5 is a schematic side view of an actuator according to the invention comprising a cowling according to a second embodiment

- Figure 6 is a rear perspective view of the electronic control circuit of the actuator;

FIG. 7 is a front perspective view of the electronic control circuit of the actuator;

FIG. 8 is a perspective view of the cord sealing ring surrounding the electronic circuit according to the invention;

- Figure 9 is a perspective view of the complete sealing bead protecting the actuator according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a motorization system comprising a four-stroke internal combustion thermal engine. The engine 1 is formed of an engine block (not shown) and a cylinder head 2 mounted on the engine block and covered with a cylinder head cover 5 delimiting with the cylinder head 4 a housing for a group of valve actuators 3 . The actuators 3 are fixed to the yoke 4 and rest on it each by a sole 4. The cylinder head cover 5 is here shown transparent to give a glimpse of the actuators 3. The general structure and operation of such a heat engine are known in themselves and will not be more detailed here.

The valve actuators 3 allow one actuation of the intake and exhaust valves to replace a camshaft. It is thus possible to control each valve individually and to achieve complex and optimized combustion cycles. The actuators are made as autonomous units. They comprise valve displacement members, generally an actuating sliding rod having an end cooperating with the valve and an integral end of a pallet received in electromagnetic coils able to exert an attraction force on the pallet in directions. opposed. The coils are connected to an integrated electronic circuit controlling and powering the displacement members of the valves.

FIG. 2 more particularly illustrates one of the actuators seen in FIG. In this embodiment, the actuator comprises a housing 9, metal, enclosing the displacement members of the valves. In addition, on a lower face 10 of the casing 9 there is a valve actuating rod 11 and its return spring protruding from the casing 9 and intended to be inserted into the cylinder head 2. The actuator 3 also comprises a plug 8 connection arranged on the front panel and which connects the electronic circuit 14 to a power source and an engine management unit or ECU (Engine Control Unit English).

More specifically, the electronic circuit bearing the reference 14 comprises a support 15, split into a first support portion 17 and a second support portion 18, and electronic components distributed on each support portion 17, 18. The support portions 17 , 18 are each respectively fixed on one face of the housing 9, here on the upper face 21 and on the front face 20. The electronic circuit 14 thus comprises two parts 14a and 14b which electrically connected together by electrical connections 24 in a zone The circuit portions 14a and 14b are thus electrically connected by rigid connections 24, arranged in two parallel combs. The connections 24 are formed of two connectors 25a and 25b, respectively connected to the circuit portions 14a and 14b, which are mechanically and rigidly connected to each other.

These connections 24 make it possible to better withstand the vibrations and the temperature than the cables and tablecloths that are usually used.

The connection zone 35 is located substantially at the junction of the front face 20 and the upper face 21. This position and the fact that the connections 24 is particularly sensitive to pollution, involves a particular cowling to protect not only the electronic circuit 14 but also the connection zone 35.

The actuator illustrated in FIG. 3 comprises a cowling 40 (shown partially in transparency) covering the electric circuit 14 and the connection zone 35. The cowling 40 has no openings, which makes it possible to ensure complete sealing of the circuit 14 and the connection area 35.

The cowling 40 comprises an upper cowl 41 fixed on the upper face 21 of the housing 9 and a front cowl 42 fixed on the front face 20 of the housing 9. The fastenings of the cowls 41 and 42 on the housing 9 are provided by clip systems. and notches 45. Each cover 41 and 42 has an open side, respectively 41 'and 42'.

Figure 4 illustrates an actuator 3 which has only the top cover 41 in place. On the actuator 3 is distinguished the support portion 18 screwed to the front face 20 of the housing 9 and the electronic circuit portion 14b has been removed.

The edges of the cover 41 delimiting the open side

41 'of the upper cover 41 bear directly on the upper face 21 of the housing 9 and therefore completely cover the support portion 17 and the circuit portion 14a. The upper cover 41 has on an adjacent side 41 '' to the open side 41 ', an opening 50 which is arranged to allow access to the interior of the upper cover 41 when the latter is fixed on the actuator. The support portion 18 fixed on the front face 20 of the actuator is a soleplate of which a fixing face 50 is fixed on the casing 9 and whose casing face 47, opposite to the fixing face 50, receives the portion of electronic circuit 14b. The adjacent side 41 '' of the cover 41 and the cowling face 47 of the support portion 18 are arranged so as to form a flat contact surface 48 adapted to receive the cover 42. The front cover 42 illustrated in FIG. 4a is arranged to rest on the contact surface 48 and to cover the second portion of the electronic circuit 14b while providing a protected cavity containing the connection zone 35. The open side 42 'of the cover 42 and the contact surface 47 have substantially the same shape and dimensions.

The two covers 41 and 42 are fixed together by a system of clips and notches 46.

Such a cowling 40 thus comprises only two covers 41 and 42 of substantially parallelepipedal shape which once assembled on the housing form an "L".

Of course, the rollover is not limited to the embodiment described above.

In particular, the cowling 40 may be disposed on more than two faces of the housing 9 and on faces other than the front and upper faces.

In addition, it is possible to make the cowling 40 using covers of different shapes. FIG. 5 illustrates an actuator 3 seen in profile on which are represented diagrammatically the covers 41 and 42. The front cover is made in the shape of an "L" in order to cover the second circuit portion 14b and a portion of the first circuit portion 14a. The upper cover 41 has only one open side while the front cover 42 has two open sides. The connection zone 35 is then fully protected by the front cover 42.

Fixing the covers 41, 42 on the housing or between them is simply performed by a system of clips and notches 45. However, it is possible to screw these covers 41, 42 on the housing 9 or even to glue.

FIG. 6 illustrates the electronic circuit 14, in a rear view, detached from the housing 9. In this figure, the first support portion 17 is shown whose fixing face 50 and the second support portion 18 are arranged perpendicularly to the first support portion 18. The first support portion 17 has metal tips 52 perpendicular to the rear face 50 and intended to be inserted into the housing 9 to electrically connect the electronic circuit 14 to the valve moving members . The tips 52 pass through the first support portion 17 through openings 53 formed in said support portion 17. The openings 53 are filled by a sealing paste which isolates the attachment face 50 of the cowling face 47.

The first support portion 17 also comprises first sealing means comprising a first sealing segment 51 and a first groove 51 'intended to receive a seal. The first sealing segment 51 is made in a "U" shape, the branches of the "U" extending towards the second support portion 18.

FIG. 7 illustrates the electronic circuit 14, in front view, detached from the housing 9. This figure illustrates in particular the rollover face 47, the electronic components of the circuit 14 having been removed to allow a better readability of the figure.

The cowling face 47 comprises the tips 52 which make it possible to electrically connect the electrical circuit, in particular the first circuit portion 14 a, to the actuating members of the valves.

The roll-over face 47 also comprises second sealing means comprising a second sealing segment 54 and a second groove 54 'which extends substantially along the perimeter of the second support portion 17.

The groove 54 'is intended to receive a seal which will seal the second electronic circuit portion 14a once the front cover 42 fixed.

The second support portion 17 comprises also connectors 25a which are arranged on an adjacent lateral face 55 to the cowling face 47 and to the attachment face 48. The lateral face 55 comprises third sealing means comprising a third sealing segment 56 and a third groove 56 '.

The three bead segments 51, 54 and 56 are arranged to form a continuous bead 59 as shown in FIG.

Thus, the second circuit portion 14b and the connectors 25 are surrounded by the sealing bead 59 and they can be isolated from the engine environment, when the circuit 14 and the cowling 40 are fixed on the housing 9.

The first sealing segment 51 is arranged to create a simple return of the sealing bead 59 on the attachment face 50 so as to isolate the connection zone 35. In fact, it is not possible to make a bead of sealing at the exact intersection between the first support portion 17 and the second support portion 18. This is why this portion of the sealing bead is transferred to the attachment face 50.

When the support 15 is fixed on the housing 9, oil infiltration by capillary action is possible between the attachment face 50 and the housing 9. These infiltrations can not go back to the electronic circuit 14 through the openings 53, because these the last are filled by a sealing paste. The infiltrations can not either go up to the connection zone 35, because they are blocked by the sealing bead segment 51.

When the casing 40 is fixed on the actuator, the upper cover 41 bears on the sealing segment 56 and the front cover 42 bears on the sealing segment 54.

Thus, once the actuator is assembled, the circuit electronics is protected, all the sealing means having been transferred to the second support portion 17.

Referring now to Figures 2, 4, 6 and 7, the sealing bead 59 is completed by sealing segments between the covers 41, 42 and the housing 9.

Thus, the upper face 21 of the housing 9 comprises a fourth sealing segment 61 comprising a fourth groove 61 'surrounding the first portion of the circuit portion 14a, that is to say that the fourth groove 61 extends substantially along the outer perimeter of the upper face 21. This groove 61 is intended to receive a seal to seal between the upper cover 41 and the upper face 21.

Similarly, the adjacent side 41 '' of the cover 41 comprises a fourth sealing segment 65 comprising a fifth groove 65 'which, after adding a seal, makes it possible to seal between the upper cover 41 and the front cover 42.

FIG. 9 illustrates the complete sealing bead 70, that is to say the bead 59 and the sealing segments 61 and 65 respectively formed by the fourth groove 61 'and the fifth groove 65'.

This complete bead 70 comprises a first pair of convergence points 66a and 66b between the sealing bead 59 and the bead segment issuing from the groove 61. The complete bead 70 comprises a second pair of convergence points 67a and 67b between the sealing bead 59 and the bead segment of the groove 65.

Each point of convergence is defined as the meeting point between the ends of at least two sealing segments.

The sealing means are arranged to form a single sealing means when the actuator is assembled. The assembly of the actuator is made in several successive stages comprising the steps of:

producing the sealing bead 59 on the first support portion 17;

- Fix the first support portion 17 on the housing 9;

attaching the second support portion 18 to the housing 9;

electrically connecting the circuit portions 14a and 14b by soldering the connections 25;

producing the sealing bead portion 61 on the top cover 41 and fixing the latter on the housing 9;

forming the sealing bead segments on the attachment face 47 and the adjacent side 41 '';

secure the front cover 42 on the attachment face 47 and the top cover 41.

The sealing segments comprise elastomer seals whose ends are joined by a polymer adhesive provided for this purpose in order to form the points of convergence.

Of course, the embodiment of the invention is not limited to the embodiment described above.

In addition, it is possible to make the cowling 40 using covers of different shapes. FIG. 5 illustrates an actuator 3 seen in profile on which are represented diagrammatically the covers 41 and 42. The front cover 42 is made in the shape of an "L" in order to cover the second circuit part 14b and a part of the first part of circuit 14a. The upper cover 41 has only one open side while the front cover 42 has two open sides. The connection zone 35 is then fully protected by the front cover 42.

Each point of convergence has three branches, but it is possible for a convergence point to have more than three branches. Thus, in the embodiment illustrated in FIG. 5, the front cover 42 is in the form of an angle so that the fifth segment of cord 65 comes to connect on the points of convergence 66a and 66b, thus creating points of convergence with four branches. .

At the same time, the points of convergence 67a and 67b only have two branches.

The sealing means may simply comprise a bead of adhesive-seal deposited in the liquid state in the grooves 51 ', 54' and 56 'or directly on the second support portion 17.

The seal is then polymerized by contact with ambient air, ultraviolet radiation or heat treatment.

This embodiment is particularly interesting because the deposit of a seal in the liquid state is easy and guarantees to fill all the grooves. In addition, this type of seal makes it possible to increase the adhesion between the pieces.

Although the electromagnetic actuator 3 of the present example is an actuator directly controlling the movement of the valve, the invention also applies to an electromagnetic actuator cylinder deactivation adapted to temporarily cut the link between the cam and the valve.

Claims

1. Device comprising a housing (9), an electronic circuit (14) for controlling the device made on at least one support (15) fixed on the device and a cover (40) for protecting said electronic circuit (14), characterized in that the support (15) of the electronic circuit (14) has a fixing face (50) on the housing (9) comprising first sealing means (54) and a covering face (47), opposite to the fixing face (50) and intended to receive the cowling (40), the cowling face (47) comprising second sealing means (51).

2. Device according to claim 1, wherein the support (15) of the electronic circuit (14) has a side face (55) adjacent to the fixing faces (50) and cowling (47) and having third sealing means (56) arranged so that the sealing means of the fastening, cowling and lateral faces form a continuous sealing bead (59).

3. Device according to one of claims 1 and 2, wherein the cowling (40) is arranged to cover the cowling face (47) and the side face (55).

4. Device according to one of claims 1 to 3, wherein the sealing means (51, 54, 56) are formed by the application of a liquid seal.

5. Device according to one of claims 1 to 4, wherein the sealing means (51, 54, 56) comprise a groove receiving a seal.

Electromagnetic actuator comprising a device according to one of claims 1 to 5.