Description

The present invention relates to a fan for a lighting device of a motor vehicle, at least comprising an impeller, a frame, and a housing, wherein the impeller is rotatably mounted on the frame, and wherein the housing is mountable on the lighting device.

PRIOR ART

Active cooling of lighting devices of motor vehicles, especially of headlights, is typically performed by means of fans generating a directional airflow inside the lighting device, especially around heat sink bodies in thermal contact with the light sources. The fan comprises a motor-operated impeller rotatably mounted on a frame, and the frame is attached to a fan housing, which is dedicated to being mounted in the lighting device, or which represents a section of the lighting device housing.

In the prior art, the attachment of the frame to the housing is typically set up by means of several screw joints. The screw joints establish a rigid coupling between the frame and the housing, so that during operation of the fan, i.e., during rotation of the impel ler, any occurrent vibrations are exhaustively transmitted from the frame to the hous ing. Such transmission of vibrations yields undesirable generation of noise, which is a disturbing factor during vehicle operation. Especially in the case of electric vehicles generating only negligible engine noise, distinct fan noise may become particularly disturbing for passengers and/or passers-by.

DISCLOSURE OF THE INVENTION

It is thus an object of the present invention to provide a fan for a lighting device of a motor vehicle, which is fixed in a robust way and allows for a basically noise-free fan operation.

This object is achieved by a fan as taught by claim 1 of the present invention. Advan tageous embodiments of the invention are defined in the subclaims. The invention discloses the technical teaching that the frame is form-lockingly fas tened to the housing, wherein the housing features compliance elements, which are in pre-loaded contact with the frame, and which are designed for damping of vibrations of the frame along three spatial axes.

The core of the invention lies in the introduction of compliance elements featuring ded icated elastic flexibility, which allow for absorption and thus damping of vibrational ex citations. Vibrations released by the impeller and/or the related motor during fan oper ation can be dissipated as mechanical work for the elastic deformation of the compli ance elements without being transmitted to the residual sections of the housing. Therefore, noise generation can be significantly suppressed with the inventive fan.

The frame is form-lockingly fastened to the housing, and in this fastened position the compliance elements form preloaded contacts with the frame to enable elastic resili ence upon vibrational movement of the frame. Especially, the compliance elements are designed for robust fixing of the frame within the housing, i.e., the preloaded con tacts with the frame contribute a significant share to the retention force holding and fix ing the frame within the housing. The compliance elements each act along different spatial directions, so that the entire set of compliance elements allows for fixation and vibration damping along three spatial axes.

Advantageously, the three spatial axes are oriented mutually perpendicular, wherein a first axis and a second axis lay in a plane perpendicular to the rotation axis of the im peller, and wherein a third axis lays parallel to the rotation axis. Such a setup allows for a comprehensive damping of vibrational excitations.

As a preferred embodiment of the inventive fan, a first compliance element yielding compliance along the first axis features an arc-shaped rack split into two halves by a gap around the apex, so that the two halves are bendable, wherein the frame is in contact to the first compliance element around the apex. The contact with the fastened frame yields a slight bending of the two halves and the elastic energy thus stored in the first compliance element exerts a pre-load on the contact with the frame. Furthermore, a second compliance element yielding compliance along the second axis advantageously features a beam with a free end section and a concave bending to wards the frame, wherein the frame is in contact to the second compliance element at the free end section. The beam exerts an elastic, inward directed force on the fas tened frame.

Moreover, a third compliance element yielding compliance along the third axis fea tures a beam with a protruding contact section, wherein the frame is in contact to the third compliance element at the contact section.

Exemplarily, the housing features at least one latch arm engaging with a correspond ing receiving section of the frame, so that the frame is fastened along the first axis. Additionally, the housing advantageously features at least two opposite notch sections enclosing corresponding tongue sections of the frame, so that the frame is fastened along the second axis and the third axis. Such a setup yields a form-locking and easy to assemble fastening of the frame with the housing without any rigid screw joints.

Preferably, the housing features a thermoplastic polymer, especially polypropylene. Thermoplastic polymers offer convenient mechanical properties yielding the desired elastic flexibility of the inventive compliance elements.

PREFERRED EMBODIMENT

Additional details, characteristics, and advantages of the object of the invention are disclosed in the following description of the respective figures - which in an exemplary fashion - shows a preferred embodiment of the fan according to the invention.

Fig. 1 a - 1 c front views of the preferred embodiment,

Fig. 2a - 2c perspective views of the preferred embodiment, and Fig. 3a - 3c rear views of the preferred embodiment. The Figures show the preferred embodiment of the inventive fan 100 in front (Figs. 1 a - 1 c), perspective (Figs. 2a - 2c) and rear view (Figs. 3a - 3c), wherein Figs. 1 a, 2a, 3a each show the isolated frame 2, Figs. 1 b, 2b, 3b each show the isolated housing 3, and Figs. 1 c, 2c, 3c each show the entire assembled fan 100.

The impeller 1 is mounted in the frame 2 rotatably around the rotation axis R likewise representing the third axis Z. The central body of the impeller 1 contains an electric motor, which is accessible for power and control signals via the electrical connection 21 . The frame 2 features four peripheral holes being originally intended for screw joints according to the prior art, two of which here serve as the receiving sections 24 for the snap-connection with the latch arms 34, i.e., with the detent lugs at the free ends of the latch arms 34 engaging with the receiving sections 24. In this way, the frame 2 is fastened to the housing 3 mainly along the first axis X. Fastening of the frame 2 along the second axis Y and the third axis Z is provided by the tongue sec tions 25 engaging with the corresponding notch sections 35 of the housing 3. This de sign accounts for a very convenient assembly process of the inventive fan 100, wherein the tongue sections 25 are inserted into the open ends of the notch sections 35 (from the upper side in the Figures) and the frame is afterwards shifted along the first axis X (from top to bottom in the Figures) until the latch arms 34 engage with the receiving sections 24.

The first compliance element 31 yielding compliance along the first axis X features an arc-shaped rack split into the two halves 31 a, 31 b by the gap around the apex, so that the two halves 31 a, 31 b are bendable, wherein the frame 2 is in contact to the first compliance element 31 around the apex. The second compliance element 32 yielding compliance along the second axis Y features a beam with a free end section and a concave bending towards the frame 2, wherein the frame 2 is in contact to the second compliance element 32 at the free end section. The third compliance element 33 yield ing compliance along the third axis Z features a straight beam with a protruding con tact section, wherein the frame 2 is in contact to the third compliance element 33 at the protruding contact section. In the idle position of the frame 2 relative to the housing 3, all three compliance ele ments 31 , 32, 33 are slightly bent outwards, i.e., elastically deformed, and thus exert a force towards the frame 2, i.e., yield preloaded contacts with the frame 2. Upon vibra tion of the frame 2 during operation of the impeller 1 , the preloaded compliance ele ments 31 , 32, 33 maintain their contacts with the frame 2 and impose a resistance against the vibrational movement of the frame 2, which yields an effective damping. The transmission of vibrations from the frame 2 to the housing 3 is thereby largely suppressed and a very low noise operation of the inventive fan 100 enabled.

The present invention is not limited by the embodiment described above, which is rep resented as an example only and can be modified in various ways within the scope of protection defined by the appending patent claims.

List of Numerals

100 fan

1 impeller

2 frame

21 electrical connection

24 receiving section

25 tongue section

3 housing

31 first compliance element 31a, b rack half

32 second compliance element

33 third compliance element

34 latch arm

35 notch section

R rotation axis

X first axis

Y second axis

Z third axis