MODULAR DEVICE FOR JOINING A TRANSDUCER TO A BUMPER

D e s c r i p t i o n

The present invention relates to a modular device for joining transducers to car bumpers.

In particular, the new disclosure relates to a modular element of new conception adapted to enable engagement between a transducer, an ultrasonic transducer for example, and a vehicle's bumper.

It is known that nowadays a plurality of ultrasonic transducers are mounted on many cars presently on the market at least at the front and rear bumpers, which ultrasonic transducers are part of a sensor system adapted to automatically facilitate/allow car parking, i.e. to signal the presence of obstacles in the vicinity of the car.

Generally, transducers are secured to the bumper by suitable modular elements acting as adapters, in engagement, on one side, with the inner surface of the bumper by a suitable plate and receiving the true transducer device, on the other side.

One of the most felt requirements on the market is the possibility of concealing both the modular engagement element and the transducer as much as possible to the sight, so that the whole sensing system may have a minimum aesthetic impact for the user.

To this aim, another requirement concerning the aesthetic aspect is linked to the planar character of the transducer head relative to the outer surface of

the bumper .

In order to meet the above mentioned requirements, in accordance with US Patent No. 6039367 a device is known which shows a bumper provided with a plurality of sensors secured to the bumper itself by use of an ^• interface consisting of a plate directly welded or glued to the inner surface of the bumper, which plate is able to receive the suitable ultrasonic transducer at a tubular rear portion thereof, said transducer, once coupled to the modular element, being in a substantially planar configuration with the outer surface of the bumper itself.

While this type of devices can very well accomplish the tasks for which they are intended, they however have some limits and drawbacks.

First of all, a portion of _ the modular element can be seen from the outside of the bumper and in addition in the engagement system of the transducer with the ' modular element it is contemplated that a circular front surface of the transducer shall particularly abut against a corresponding annular portion of the modular ^' element itself, at the hole formed on said bumper.

Moreover, the ultrasonic transducer is retained at the rear region by suitable elastic tabs and corresponding engagement teeth.

The above involves that possible errors or tolerances on the -axial sizing of the transducer may possibly give rise to slack engagements of the transducer itself so that it can be submitted to axial displacements during operation. It is clear that these displacements involve

subsequent measuring errors and, as a result, a less reliable operation of the sensor.

Vice versa, in the opposite condition, problems of engagement could occur, due to the excessive length of the transducer relative to the modular interface element .

Also known from the European patent No. EP981763 is a transducer coupling system applicable to inner surfaces of bumpers in which the .external aesthetic impact of the transducer is reduced to the minimum, said transducer being exclusively visible at a cylindrical head portion substantially positioned in a flat configuration with the outer surface of the bumper.

From an operating point of view this device has the same drawbacks set out above as regards the engagement configuration of the transducer to the modular structure and also has some problems for coupling of the ultrasonic signal due to the vicinity of the transducer head to the bumper body.

The present invention aims at substantially solving the above mentioned drawbacks.

Accordingly, it is a first aim of the invention to make available a joining element for ultrasonic transducers having the smallest possible aesthetic impact, while at the same time ensuring an optimal reliability in operation.

It is a further aim of the invention to make available an engagement system between modular element and transducer different from those in accordance with the

known art, which is capable of ensuring an optimal reliability and of compensating for possible tolerances and design errors.

The foregoing and further aims are substantially achieved by a joining system for transducers in accordance with the present invention.

Further features and advantages will become more apparent from the detailed description of a preferred but not exclusive embodiment in accordance with the appended claims .

The invention will be hereinafter described with reference to the accompanying drawings, given by way of non-limiting example, in which:

- Fig. 1 is a cross-sectional view of a joining system for transducers in ' accordance with the present invention; and - Fig. 2 shows the device seen in Fig. 1 in section in a plane rotated through 90°;

- Fig. 3 shows an advantageous alternative embodiment of the device in Fig. 1;

- Figs. _. 4a and 4b diagrammatically show the variations

_Y* ..- -• in the exit angle of the ultrasonic signal at different operating configurations of the device in accordance with the invention; and

- Figs. 5a, 5b and 5c are a perspective view, a front view and a sectional view respectively, of the transducer head and packing in an advantageous configuration according to the invention.

With reference to the drawings, generally denoted at 1 is a joining system for transducers according to the present embodiment.

As can be seen from the figures, the transducer assembly device comprises two main elements, at least one transducer 2, generally an ultrasonic transducer, capable of emitting and receiving the suitable signal to be then subsequently processed for determining the proximity information concerning an obstacle, to be sent to the driver, and at least one modular element 3 adapted to enable transducer 2 to be joined to the bumper .

The modular element 3, generally made of plastic material and by moulding, first of all comprises a fastening portion 3a designed to be joined to the inner surface Ia of a bumper.

In particular, the fastening portion 3a has a plate- like body 8 that will be directly secured to the inner surface Ia of said bumper. This plate-like body 8 can be glued or welded to the bumper or possibly also made of one piece construction therewith.

The fastening portion 3a also has a protruding annular element 9 that, under operating conditions, is designed to be inserted into the through cavity 10 of the bumper as shown in the accompanying figures, so as to define a lead-in and guide element during the assembly step.

Also present at the front region of the modular element 3 is a packing 4 (this packing can be made of rubber or any other suitable material) ; packing 4 emerges from the fastening portion 3a on the opposite side relative to an insertion region of the transducer, and at the centre thereof defines a through seat 4a that is substantially circular and is designed to enable passage of the transducer head 7 in the assembled

condition of the modular element 3 and transducer 2.

In detail, packing 4 is irremovably secured to the fastening portion 3a and in particular it is directly secured to the protruding annular element 9.

"Packing 4 can be co-moulded on the protruding element 9 or glued thereto or also mechanically secured thereto in a suitable manner.

Obviously, should the annular element 9 be absent, said packing would be directly secured to the fastening portion 3a at the plate-like body.

Transducer 2 has a head 7 and a central body 11 having a transverse bulkiness greater than the transverse bulkiness of head 7. The difference in the two bulkiness sizes defines a connecting annular surface 11a which is oriented transversely of (in particular orthogonal to) the axial extension direction A of head 7.

At the rear region of transducer 2 there is an electric connector 14 adapted to enable wiring to a suitable card or controller capable of sending and processing the signals generally received from a plurality of said transducers mounted on the bumper itself.

In the embodiment shown in Fig. 2, connector 14 juts out transversely (preferably perpendicularly) relative to the axial extension A _. of transducer 2.

In another embodiment, connector 14 axially juts out along the extension A of the transducer.

At all events other embodiments will be possible.

As shown in the accompanying drawings, in the assembled condition between the modular element 3 and transducer 2, the transducer head juts out relative to the fastening portion 3a on the side opposite to the insertion portion 3b of the modular element 3.

In detail, head 7 has an upper surface 7a that is typically circular and is disposed substantially flat relative to the outer surface of bumper 1. In particular, the upper portion of head 7 crosses said through seat 4a of packing 4 which fully surrounds the transducer at the region turned towards the outside of the vehicle.

Still as shown in the accompanying drawings 1 and 2, the outer surface of bumper 1, packing 4 and upper surface 7a of the transducer are in a substantially flat configuration.

In this manner, packing 4 prevents possible dirt, particles or other matter from penetrating into the device thus hindering correct detection of the signal and/or correct positioning of the transducer.

In addition, packing 4 has the important function of separating the vibrations between transducer 2 (and in particular the transducer head 7) and bumper 1.

Still with reference to the figures, first constraining means 5 is present for securing transducer 2 to the modular element 3, which means is adapted to prevent axial sliding of the transducer relative to the modular element along the axial direction A, in a first way.

In particular, the first constraining means 5 prevents the transducer from slipping off the modular element 3 in a direction away from bumper 1, i.e. from coming out of the insertion end 12 of the modular element.

Generally, this first constraining means 5 is defined by suitable tongues protruding from the side surface of the central body 11 of transducer 2, which tongues are snap-engaged in corresponding slots or seats present in the side surface 13 of the modular element 3, as diagrammatically shown in Fig. 1.

Also present is second constraining means 6 to secure the modular element 3 to transducer 2, which means is adapted to prevent axial sliding of the transducer relative to the modular element along said axial direction A, in the opposite way to that inhibited by the first constraining means 5.

The second constraining means 6 that is placed at said side surface 13 of the insertion portion 3b defines the maximum insertion . point of transducer 2 into the annular element .

Generally, although not necessarily, the second constraining means 6 is placed at a median region of the transducer in close proximity to said first constraining means 5.

The engagement defined by the second constraining means 6 is at least partly of the resilient type along the axial direction A to allow • compensation for possible tolerances during the engagement step of transducer 2 with the modular element 3.

In particular, the second constraining means 6 comprises an abutment body 15, defined by a suitable pin or projection for example, which is designed for insertion into a housing seat 16 present in the side surface 13 of the modular element 3.

In particular, the housing seat 16 has such a conformation that it can receive the abutment body 15 until a position at which said body abuts against the side walls of the housing seat 16.

Since said seat 16 is substantially open towards the rear portion and resiliently deformable, a further pressure in the inserting action of the transducer causes resilient deformation of the seat and allows a more advanced insertion position to be reached by the transducer, due to the resilient deformation of the housing seat 16 itself.

Once inserted in place, the spring-back action due to the housing seat 16 coming back to its undeformed condition generates a thrust towards the insertion end 12 of the modular element of such a nature as to bring the first constraining means 5 safely in abutment against the seat of the modular element 3, thus locking the transducer in place.

It is apparent that due to deformability of the housing seat 16, possible production tolerances can be compensated for, so that a reliable engagement of the transducer with the modular element can be always and at all events ensured, the transducer being always maintained in place and reliability of the signal detection being increased.

In a preferred embodiment, the first constraining means 5 and second constraining means 6 can be defined by a single constraining element, capable of performing the functions as said means 5 and 6.

Still from a construction point of view it is also to be pointed out that said connecting surface 11a in the assembled condition is spaced apart from the modular element 3. In other words, surface 11a is not designed to come in abutment on any portion of the modular element 3. The space defined between said surface and the modular element can possibly be used for housing a further packing, should it be necessary.

It will be recognised that the described configuration appears to be very advantageous because packing 4 is exactly positioned relative to transducer 2, due to the fact that it is irremovably secured to the modular element 3 in a precise manner. This not only allows positioning of packing 4 to be determined with the greatest accuracy, but also enables the angular position of same to be exactly established, on mounting. In fact the packing has a cylindrical tubular shape that, if merely arranged on the transducer head, would lose any type of angular reference. Vice versa, in. the present situation, positioning of. each portion of packing 4 can be easily controlled during the mounting step of the device.

The embodiment shown in Fig. 3 illustrates a packing 4 having a suitable material relief 4c.

It is to be noted that the relative positioning between the outer surface 4b of packing 4 (surface facing outwards of bumper 1) and the upper surface 7a of the

transducer head. 7 has an influence on the exit angle α of the ultrasonic wave beam S.

In fact, as shown in Figs. 4a and 4b, a more rearward positioning of surface 4b of packing 4 relative to surface 7a of head 7 will give rise to an amplitude decrease in the exit angle of the ultrasonic signal (or, in other words, α > α' ) .

It is therefore possible to utilise this particular geometric arrangement for varying the exit angle α of the ultrasonic wave beam S in a controlled (and possibly asymmetric) manner.

By way of example only, the lower portion of packing 4 could have said relief 4c (Figs. 5a-5c) in such a manner that the ultrasonic wave beam S directed to the ground has an exit angle smaller that the upper exit angle (Figs. 3 and 5c) and is therefore less affected by the reflections of the ground (for instance, let us think of the presence of manholes or small obstacles when going into reverse that often give a false positive) .

In another case it will be also possible to ^' position said material relief 4c at a side end sensor of the bumper, and suitably turn it outwardly.

In this manner all risks of a false positive at detection regions of small interest will be reduced, as they are external to the side bulkiness of the vehicle.

It is also apparent that by suitably modulating this depth it will be also possible to correspondingly modulate the width α of the exit angle of the

ultrasonic wave beam S from transducer 2. In other words, the inventive concept is linked to the fact that the soft material used for separating the vibrations between the transducer and bumper (in both directions) can be closer .to the transmission surface 7a or farther from the transmission surface 7a depending on the requirements of the designer who therefore can decide on how to influence the shape of the ultrasonic pulse train that is transmitted.

Differently said, the designer can decide to have a narrower beam, in the vertical plane and in the lower region for example, in order to avoid sound flexures, and/or can decide to also reduce the beam at the side portions so as to better cover the regions of interest of the vehicle. In fact, not only it is possible to move packing 4 fully backward as shown in Fig. 4b, but it is also possible ■ to suitably modify the geometry thereof (Fig. 5a) in such a manner that the distance d between the profiles p_ of the outer surface 4b of packing 4 can vary as a function of an angular coordinate θ defined in a Cartesian plane centred oh axis A and positioned in the plane of the transducer surface 7a.

Fig. 5a shows a situation in which if θ=0°, d=0, while if θ=180°, d≠O . Obviously, profiles of any kind depending on requirements can be generated.

The invention achieves important advantages.

First of all, the assembly or joining device in accordance with the invention allows a simple and reliable engagement between the ultrasonic transducer and bumper, with the whole structure substantially

concealed to the eyes, except for packing 4 and the transducer head.

Transducer 2 is removably in engagement with the modular element and therefore it can be replaced in case of breaking or failure.

In addition said transducer can be connected for insertion to the modular element 3 at the end 12 opposite to the. fastening portion 3a, i.e. from the inside of the vehicle in such a manner that it cannot be easily removed under normal use conditions of the vehicle .

.Due to the presence of packing 4, no accumulation of dust or dirt occurs at the inside of the modular element, so that the operating reliability of same is increased and the risks of damaging it are reduced.

Furthermore, the constraining means herein adopted always allows a reliable engagement of the transducer, irrespective of the presence of possible tolerances.

Moreover, quite advantageous is the fact of adopting a packing that can have a surface surrounding the transducer having portions placed to a greater or smaller distance from the transmission surface of the transducer itself, so that the width of the ultrasonic wave beam can be modulated at will in the selected directions.