This invention relates to a ventilation device for a motor vehicle. This invention furthermore relates to a mold for producing such ventilation device and a method for producing the ventilation device by means of the mold.
In a motor vehicle, a ventilation device serves to relieve an excess pressure in the interior of the vehicle, as it can occur when a door is slammed, a fan is running, an airbag deploys, etc. The ventilation device usually has a housing with an outer frame as well as longitudinal and transverse beams. One or more ventilation flaps are attached to the housing and in the closed position rest on the frame and/or on the longitudinal and transverse beams of the housing. The ventilation device is inserted into an opening of the vehicle body, the frame being provided with a circumferential seal.
Ventilation devices in which the ventilation flaps are mounted to the housing involve a high mounting effort. As regards the thickness of the ventilation flaps, it was found that thinner ventilation flaps cause less rattling noise. Eventually, the ventilation flaps should be rather flat, in order to ensure a sufficient tightness in the closed position.
A ventilation device comprising a housing made of plastics and at least one ventilation flap molded to the housing is known from European patent EP 0 912 357 B1. During production of the ventilation device, the ventilation flap is molded to the housing in the open position in an injection mold, starting from the free end of the ventilation flap.
Published German Patent Application DE 100 52 003 A1 discloses a ventilation device, in which the ventilation flap is molded, but not molded directly to the housing. Rather, a purely mechanical connection of the ventilation flap to the housing is desired, in that a sealing lip of the ventilation flap extends through a fixing slot in the longitudinal beam of the housing, the cross-section of the sealing lip being thickened on both sides of the slot.
It is an object of the invention, to provide for an efficient series production of a simply designed ventilation device, which can meet the usual requirements in terms of functionality.
According to the invention, a ventilation device for a motor vehicle comprises a housing made of plastics and at least one ventilation flap molded to the housing. The housing has an opening in the connecting region of each ventilation flap. This design allows to directly mold the ventilation flap to the frame or to a longitudinal beam in a simple manner from the back of the ventilation device.
The invention also provides a mold for producing a ventilation device in accordance with the invention. The mold has two cores, which in an injection position define the contour of a ventilation flap and in a demolding position provide for demolding the molded part formed in the mold. An opening is formed in the injection position between the two cores in the connecting region of the ventilation flap. After molding the housing, such mold can be used to introduce the plastic compound through the opening in the housing between the two cores to form the ventilation flap.
To provide for first molding the housing in the same mold, a sealing element is provided for optionally sealing the opening. This ensures that no plastic compound can enter between the cores while molding the housing.
What is particularly advantageous for an efficient series production of the ventilation device is a mold which includes a first part having a plurality of cavities and an opposite second part having nozzles for injecting various plastic compounds. The first part is transferable relative to the second part from a first injection position into a second injection position. Thus, various injection processes can be performed with the same mold for simultaneously producing a plurality of ventilation devices.
Preferably, the cavities are arranged such that in the second injection position first cavities take the same position as second cavities in the first injection position. This provides for a cyclic operation with successive injection processes without having to remove the intermediate products from the mold.
Finally, the invention also provides a method for producing a ventilation device according to the invention by means of a mold according to the invention. The method includes the step of molding the ventilation flap to the housing through the opening in the housing.
According to a particularly efficient embodiment the method includes the following steps:
the two steps being performed in parallel in the first injection position of the mold.
a shows an enlarged view of the detail Z from
The elongated housing 12 is made of a rigid plastic material (a first injection molding component) and includes an outer frame 18, a longitudinal beam 20 and a plurality of transverse beams 22. Other embodiments with a different number of longitudinal or transverse beams are, however, also possible.
The very thin, flat and straight-edge ventilation flaps 14 are made of a softer plastic material (a second injection molding component) and are (injection)-molded to the frame 18 and/or to the longitudinal beam 20 such that they adhere to the same. To provide for molding the ventilation flaps 14 from the back of the housing 12, which will be explained in detail below, the frame 18 and the longitudinal beam each have a rear slot 24, as shown in
The seal 16 circumferentially molded to the frame 12 can be formed of the same material as the ventilation flaps 14 or of a third injection molding component.
In
In the following, the process of manufacturing the ventilation device by a multi-component injection molding method will first be described with reference to a single ventilation device 10, and subsequently the cyclic series production of a plurality of ventilation devices 10 will be described.
As shown in
In
For demolding (removing from the mold) the finished ventilation device 10, the second contour-forming core 28 is advanced from the injection position as shown in
At the beginning of the series production, the housings 12 are molded (first injection molding component) in the closed position of the mold with the nozzles 34 of the nozzle-side part 42 in the first two cavities 44a, 44b of the ejection-side part 40 by using the sealing elements 30. Then, the housings 12 are cooled. The mold is opened, the sealing elements 30 are removed from the first cavities 44a, 44b and the ejection-side part 40 is rotated through 180°. Upon closing the mold, the ventilation flaps 14 and the seals 16 now are molded (second and, possibly, third injection molding components) in the first cavities 44a, 44b. Parallel thereto, i.e. at the same time (in the same working step), the housings 12 are molded (first injection molding component) in the second cavities 46a, 46b by using the sealing elements 30.
After cooling the ventilation flaps 14 and the seals 16 in the first cavities 44a, 44b and the housings 12 in the second cavities 46a, 46b, the mold is opened. In the first cavities 44a, 44b, the second cores 28 are advanced into the demolding position, the ventilation flaps 14 are released and the molded parts are demolded by the ejectors. Thereafter, the ejectors and the second cores 28 are again returned into the injection position.
The ejection-side part 40 is rotated back into its starting position through 180°, so that again, as described above, housings 12 can be molded in the first cavities 44a, 44b and ventilation flaps 14 and seals 16 can be molded in the second cavities 46a, 46b. This cycle now can be repeated any number of times.
Number | Date | Country | Kind |
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10 2007 026 385.8 | Jun 2007 | DE | national |