EP0976902A1 - Electric lock module for the boot lid of a vehicle - Google Patents

Abstract

The lock has a bolt (20) pivoting about an axis (21) to engage with a striker, and a catch (30) with a return spring (36) turning about a pivot (31) to lock the bolt in its closed position. The catch and bolt are released by an electrical actuator (40) with at least one motor (41) and a cylindrical cam (45) with a spiral control groove (46) for a carriage (70). The carriage is coupled directly to the catch by a loop (72) and has at least one follower for the cam groove in the form of a spiral projecting rail. The length of the loop is greater than the thickness of the protruding portion of the catch it engages with to allow for play on engagement.

Description

The present invention relates to an electric lock module for a trunk motor vehicle comprising at least one bolt pivoting about an axis and arranged to close on a keeper, a pawl pivoting about an axis and arranged to lock the bolt in the closed position on the strike, the pawl being subject to a return device towards the bolt, and electrical actuation means of the ratchet to unlock said bolt, these electrical actuation means comprising at least one electric motor rotating a cam cylindrical carrying at least one helical control groove and on which is mounted a carriage movable in translation, this carriage being mechanically coupled to said pawl, the cylindrical cam being arranged to rotate in one direction under the action of the electric motor and in the opposite direction under the action of a return device.

There are many embodiments of electrically operated locks for the trunk of a vehicle. Generally, the actuation means are external to the lock and require significant space in the trunk of the vehicle. These actuating means generally comprise an electric motor and a device of transverse mechanical transmission of the ratchet movement by trains gears, lever systems or others. The effort to exert on the ratchet at the time of its opening is important because it depends on the thrust exerted by the joint between the boot and the body. Therefore, the engine must be sufficiently powerful and appropriately sized. On the other hand, the transmission of the movement being done transversely, the motor must turn in the two directions respectively to open and to close the pawl. This implies heard suitable engine control electronics.

Another concept has been developed in order to simplify this electronic ordered. These are actuation means comprising a worm and a train gears, the last pinion carrying an eccentric trigger finger and arranged to press the pawl and open it during the rotation of said pinion. The return in closed position of the pawl is, in this embodiment, ensured by a return spring. However, after opening the pawl, it is necessary to precisely position the trigger finger to return to its original position. This operation is not not easy to perform given the inertia of the engine. The risk is that the finger of trip is positioned, when the engine is stopped, at a location which prevents the ratchet to return to its closed position allowing it to lock the latch on the spoils. To solve this problem, the bolt has been extended upwards to block the trigger finger in a fixed and stable position after opening the pawl and until the engine stops. However, this blocking principle generates efforts important in terms of the worm and the motor, which causes problems wear and premature fatigue of the actuating means.

Yet another concept has been developed to provide a technical solution different. These are actuation means as defined in the preamble and described in the publications DE-A-195 01 493, DE-A-195 45 722 and EP-A-119 133, these means being reversible under the action of a specific spring member. In these embodiments, the actuating means comprise a motor driving a screw without end by a gear train, this screw being coupled to a carriage movable in translation controlling the bolt locking pawl. However, the ratchet control is not performed directly, the carriage being coupled to an intermediate lever which even is coupled to the ratchet, which complicates the kinematic chain and the transmission some efforts. In addition, the spring member which allows the return of the kinematic chain in initial position consists of a specific spiral spring provided directly on the worm at the reducer, which makes these realizations complex and expensive because of the multiplicity of parts.

The purpose of the present invention is to overcome the drawbacks mentioned above by offering much simpler, economical means of actuation, reliable. safe and ensuring correct positioning of the pawl without generating other disadvantages.

This goal is achieved by the lock module as defined in the preamble and characterized in that the carriage is directly coupled to the pawl and in that said device recall consists only of the pawl recall device.

The carriage advantageously comprises at least one follower element of the groove helical control, this follower element being able to comprise at least one rail protruding helical having a profile complementary to that of the helical groove control.

In a preferred embodiment of the invention, the carriage has a loop coupling arranged to receive the upper end section of the pawl. This coupling loop preferably has a length greater than the thickness of the section upper end of the pawl so as to provide sufficient clearance for allow the deflection of said pawl when locking the bolt.

In the preferred embodiment, the carriage comprises guide means in translation to prevent its rotation and at least one stop arranged to rest against at least one stop wall formed in the lock module defining a initial position of the pawl corresponding substantially to the locked position of the bolt.

Advantageously, the angle of inclination of the helical groove for controlling by relative to the axis of the cylindrical cam is judiciously chosen to allow the reversibility of the actuating means in a range of about 45 ° to 60 °. Drug cylindrical preferably comprises two helical grooves parallel to each other and shifted by half a step.

The electrical actuation means may also include a train of gear coupling the shaft of the electric motor to the cylindrical cam, this train gear being chosen to increase the speed of said motor. It comprises advantageously at least two toothed pinions of which at least one is made of synthetic materials to reduce the coefficient of friction.

The electric motor is also chosen to have a low residual torque when it is not powered.

In the preferred embodiment, the cam and the carriage are made in different synthetic materials arranged to reduce their coefficient of friction, one of the parts can be made of polyamide 66 and the other part of polyoxymethylene.

Preferably, the pivot axis of the bolt, the pivot axis of the pawl and the fulcrum between the hook and the notch are judiciously positioned by relation to the strike axis so as to obtain an optimized force diagram, in which the force of the pawl is less than the force of the keeper supported by the bolt, for a given strike force, the force of the pawl being substantially equal to a third of the effort of waste.

• la figure 1 est une vue de face du module serrure en position verrouillée,
• la figure 2 est une vue de dessus du module de la figure 2,
• la figure 3 est une vue en perspective du cliquet,
• la figure 4 est une vue en perspective du chariot,
• les figures 5A et 5B représentent schématiquement le module de serrure respectivement en position verrouillée et en position déverrouillée, et
• la figure 6 représente le diagramme d'efforts entre le pêne et le cliquet.

The present invention and its advantages will be better understood in the following description of an embodiment given by way of nonlimiting example and with reference to the appended drawings, in which:

• FIG. 1 is a front view of the lock module in the locked position,
• FIG. 2 is a top view of the module of FIG. 2,
• FIG. 3 is a perspective view of the pawl,
• FIG. 4 is a perspective view of the carriage,
• FIGS. 5A and 5B schematically represent the lock module respectively in the locked position and in the unlocked position, and
• Figure 6 shows the force diagram between the bolt and the pawl.

With reference to FIGS. 1 to 4, the electric lock module 10 according to the invention and intended to equip the boot of a motor vehicle mainly comprises a bolt 20 pivoting about an axis 21 and arranged to close on a keeper, whose axis is shown in point G, mounted on the vehicle body, a pawl 30 pivoting around an axis 31, parallel to the axis 21, and arranged to lock the bolt 20 in position closed on the keeper and electrical actuating means 40 arranged to open the pawl 30 and unlock the bolt 20 to release the strike. These main elements are gathered in a box 60 constituting a compact module and intended to be directly mounted on the flap of a trunk (not shown). Box 60 comprises a drain 61 intended to receive said keeper. This case 60 will not described in more detail.

The bolt 20 comprises, in known manner, at its base, a hook 22 adapted to receive said keeper and, on its right side, at least one notch 23 intended to cooperate with the pawl 30. The bolt 20 is subject to a return device consisting of a spring return 24 coaxial with its pivot axis 21 and having two free ends, one 24a being supported on the housing 60 on the left side of the drain 61 and the other 24b being supported on the right side of the bolt 20 so as to create a torque clockwise tending to open the bolt 20. The pivot axis 21 of the bolt 20 is advantageously offset to the left of the axis G of the keeper. In the upper part of the bolt 20, a finger 25 is provided which is arranged to cooperate with a microswitch 26, when the bolt 20 is in the locked position, to control for example the light safe, alarm, etc.

The pawl 30 comprises, in a known manner and with particular reference to the Figure 3, a lower arm 32 terminated by a hook 33 arranged to be housed in the notch 23 of the bolt 20 and an upper arm 34 terminated by an end section upper 35 curved and intended to cooperate with the actuating means electric 40. This pawl 30 is subject to at least one return device constituted a spring 36 coaxial with its axis 31 and having two free ends, one 36a being supported on the housing 60 on the right side and the other 36b being supported on the side left of the pawl 30 above its axis 31 so as to create a couple of clockwise rotation tending to bring the pawl 30 closer to the bolt 20. The axis of pivoting 31 of the pawl 30 is advantageously offset to the right of the fulcrum between the hook 33 and the notch 23 of the bolt 20, this fulcrum also being offset at right of the G axis of the strike.

The actuating means 40 include an electric motor 41, a train gear 42 comprising two toothed pinions 43, 44, an endless screw called by the following cylindrical cam 45 movable in rotation and a carriage 70 movable in translation mechanically and directly coupled to the pawl 30. The toothed pinions 43, 44 may have straight, angled or helical teeth but are arranged to be able to turn in one direction as well as the other. The electric motor 41 is chosen to have a low residual torque when it is not powered to facilitate its reversibility.

The cylindrical cam 45 is rotated about its axis by the motor electric 41 by means of the gear train 42 which increases the speed of rotation of the motor. The toothed pinions 43, 44 therefore form a reduction gear, the driving pinion 43 being made of metal and the other pinion 44 of synthetic materials, such as by example of polyamide 66, to reduce the coefficient of friction and facilitate reversibility of the reducer. The cylindrical cam 45 comprises, in the example shown, two helical control grooves 46 parallel to each other and inclined relative to the axis of the cam at an angle of inclination judiciously chosen for facilitate its reversibility, and for example in a range of 45 ° to 60 ° relative to the axis of the cam and in the example shown substantially equal to 53 °. This number of grooves helical can be reduced to one or three as required. The tilt angle of the helical groove 46 allows the rotation of the cylindrical cam 45 as well in a direction under the action of the electric motor 41 than in the other direction under the action of the return spring 36 of the pawl 30 as explained below.

The carriage 70 is mounted on this cylindrical cam 45 and is driven in translation the along this cam when the latter is rotating by means of a follower element helical control grooves 46. This follower element is provided in the left section 71 and in this embodiment consists of a double helical rail protuberant having a profile complementary to that of the helical grooves of control 46. To reduce the friction between the cam 45 and the carriage 70, these parts are made of different synthetic materials, such as for example polyamide 66 for cam 45 and polyoxymethylene for carriage 70. In addition, to further reduce this friction, a special plastic grease is interposed between these two parts in the helical grooves.

Referring more particularly to FIG. 4, this carriage 70 comprises the section 71 in engagement with the cylindrical cam 45. It has an elongated shape and ends in a coupling loop 72 arranged to receive the upper end section 35 of the pawl 30. This coupling loop 72 has a length greater than the thickness of the upper end section 35 of the pawl to provide sufficient clearance allowing the movement of said pawl 30 when the latch 20 is locked. The carriage 70 comprises between the section 71 and the coupling loop 72 a central portion 73 formed of two parallel longitudinal walls 74 defining between them a space vacuum 75 intended to receive the end of the cylindrical cam 45. These walls longitudinal 74 each have a rail 76 on their outer face, this rail being intended to slide in a corresponding groove provided in the housing 60 of the lock module 10. These rails 76 provide both guiding in translation of the carriage 70 and prevent it from turning. The longitudinal walls 74 have also upper and lower stops 77 intended to position axially said carriage 70 relative to a stop wall 62 formed in said housing for guarantee correct positioning of the carriage 70 when the pawl 30 is in its initial position corresponding substantially to the locked position of the bolt.

The operation of this lock module is detailed with reference to FIGS. 5A and 5B which schematically illustrate the bolt 20, the pawl 30, the means electric actuator 40 and the housing 60 shown in dotted lines.

In FIG. 5A, the lock module 10 is in the locked position. The bolt 20 is closed on the keeper (not shown) housed in the drain 61 ensuring the locking of the trunk flap. The pawl 30 maintains the bolt 20 in this position by means of its hook 33 in engagement with the notch 23 thanks to its return spring 36 which urges it around its axis 31 clockwise. The electric motor 41 is stopped and the carriage 70 is in the position defined by the stop wall 62 on which the stops 77 are in contact. In this position of the carriage 70, the coupling loop 72 is arranged in such a way that the upper end section 35 of the pawl 30 is close to its front part. The pivot axes 21 and 31 of the bolt 20 and the pawl 30 as well as the fulcrum between the notch 23 and the hook 33 are positioned judiciously relative to the axis G of the keeper to obtain a force diagram optimized, as shown in Figure 6. For a given strike force Fg, we only obtains a ratchet force Fc equal to 1/3 of Fg. This means that only 33% of the vertical force of the keeper is passed on to the pawl implying an effort opening of the pawl weak for a given strike force.

In FIG. 5B, the lock module 10 is in the unlocked position. To pass from the locked position (Figure 5A) to the unlocked position, the electric motor 41 has been activated to rotate the cylindrical cam 45 and move the carriage 70 towards left. During this translational movement, the carriage 70 has driven the section upper end 35 by the coupling loop 72 by pivoting the pawl 30 around its axis 31 in the counterclockwise direction, which compresses the return spring 36. During this rotational movement, the hook 33 is released from the notch 23 releasing the bolt 20, which opens under the effect of its return spring 24 and authorizes the release of the strike plate and opening of the boot lid. Thanks to the diagram optimized effort as described above, the effort required to open the pawl 30 is low, i.e. 1/3 of the strike force, which reduces power and dimensions of the actuation means of the invention and of using an electric motor 41 with low torque.

After unlocking the lock module 10, the electric motor 41 is deactivated. The return spring 36 relaxes by turning the pawl 30 clockwise to bring its lower arm 32 closer to the bolt 20, the latter remaining open under the action of its spring 24. During this rotational movement, the end section upper 35 of the pawl 30 exerts pressure on the front of the coupling loop 72, which has the effect of moving the carriage 70 in translation to the right and until that the stops 77 are in contact with the stop wall 62. The displacement in translation of the carriage 70 drives the cylindrical cam 45, the gear train 42 and the motor 41 in reverse rotation. This return of the pawl 30 to the initial position is permitted because the kinematic chain formed by the electric motor 41, the gear train 42 and the cylindrical cam 45 is reversible as previously explained and thanks to the judicious choice of certain technical characteristics, namely the materials between the parts in contact, the motor, the angle of inclination of the cam and the return spring 36 the pawl which is defined in such a way that it alone resets the electrical actuation means 40. This simple system therefore makes it possible to remove complicated control electronics or a mechanical device unreliable blockage and producing harmful side effects.

It is clear from this description that the invention achieves the planned objectives. The electrical actuation means 40 are particularly simple, efficient, inexpensive, compact and allow automatic repositioning of the pawl 30 in its initial position ready to lock the bolt 20.

The present invention is not limited to the embodiment described but extends to any modification and variant obvious to a person skilled in the art. The shape, the dimensions and arrangement of the different parts making up the lock module 10 may vary depending on the shape of the trunk of the vehicle, the main thing being respect the ratchet control principle 30 by a movable carriage 70 in translation as well as the choice of different characteristics allowing reversibility of the kinematic chain. Return springs 36 and 24 can be replaced by a single spring if the construction of the lock allows it. However, in this case, it the spring must be dimensioned to provide a necessary effort and sufficient to reset the actuating means.

Claims (16)

Electric lock module (10) for a motor vehicle trunk comprising at least one bolt (20) pivoting about an axis (21) and arranged to be close on a keeper, a pawl (30) pivoting about an axis (31) and arranged to lock the bolt (20) in the closed position on the keeper, the pawl being subject to a return device (36) in the direction of the bolt, and actuation means electric (40) of the pawl to unlock said bolt, the actuation means electric (40) comprising at least one electric motor (41) driving in rotation a cylindrical cam (45) carrying at least one helical control groove (46) and on which is mounted a carriage (70) movable in translation, this carriage being coupled mechanically at said pawl (30), the cylindrical cam (45) being arranged to turn in one direction under the action of the electric motor (41) and in the opposite direction under the action of a return device, characterized in that the carriage (70) is coupled directly to the pawl (30) and in that said return device consists only the return device (36) of the pawl (30). Lock module according to claim 1, characterized in that the carriage (70) comprises at least one follower element of the helical control groove (46). Lock module according to claim 2, characterized in that the follower element comprises at least one protruding helical rail having a profile complementary to that of the helical control groove (46). Lock module according to any one of the preceding claims, characterized in that the carriage (70) has a coupling loop (72) arranged to receive the upper end section (35) of the pawl. Lock module according to claim 4, characterized in that the buckle coupling (72) has a length greater than the thickness of the end section upper (35) of the pawl so as to provide sufficient clearance to allow the deflection of said pawl (30) when the bolt (20) is locked. Lock module according to any one of the preceding claims, characterized in that the carriage (70) comprises guide means (76) in translation to prevent its rotation. Lock module according to any one of the preceding claims, characterized in that the carriage (70) has at least one stop (77) arranged to lean against at least one stop wall (62) formed in a module housing lock (10) defining an initial position of the corresponding pawl (30) substantially in the locked position of the bolt (20). Lock module according to any one of the preceding claims, characterized in that the angle of inclination of the helical control groove (46) relative to the axis of the cylindrical cam (45) is carefully chosen to allow the reversibility of the actuating means (40) in a range of about 45 ° to 60 °. Lock module according to any one of the preceding claims, characterized in that the electrical actuation means (40) comprise a train gear (42) coupling the shaft of the electric motor (41) to the cylindrical cam (45), this gear train (42) being chosen to increase the speed of said motor. Lock module according to claim 9, characterized in that the train gear (42) comprises at least two toothed pinions (43, 44) of which at least one is made of synthetic materials to reduce the coefficient of friction. Lock module according to any one of the preceding claims, characterized in that the cylindrical cam (45) has two helical grooves of control (46) parallel to each other and offset by half a step. Lock module according to any one of the preceding claims, characterized in that the electric motor (41) is chosen to have a residual torque weak when not powered. Lock module according to any one of the preceding claims, characterized in that the cam (45) and the carriage (70) are made of materials different synthetics arranged to reduce their coefficient of friction. Lock module according to claim 13, characterized in that one of the parts (45, 70) is made of polyamide 66 and the other part (70, 45) is made of polyoxymethylene. Lock module according to any one of the preceding claims, characterized in that the pivot axis (21) of the bolt, the pivot axis (31) of the ratchet and the fulcrum between the hook (33) and the notch (23) are positioned judiciously relative to the axis (G) of the strike so as to obtain a diagram of optimized forces, in which the force of the pawl (Fc) is less than the force of strike (Fg) supported by the bolt, for a given waste effort. Lock module according to claim 15, characterized in that the force of the ratchet (Fc) is substantially equal to one third of the strike force (Fg).

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