The present invention relates to an air-distributor box for a heating or air-conditioning system of motor vehicles, and more particularly, to an air-distribution box with a first air-outflow orifice for connection of a lateral nozzle arranged laterally in a motor vehicle, a second air-outflow orifice arranged below the first air-outflow orifice for ventilating a motor vehicle foot space, and an air flap controlling an air stream to the second air-outflow orifice.
In the air-distributor box described, for example, in DE 3,925,726 A1, the arrangement of the second air-outflow orifice for ventilating the foot space underneath the first air-outflow orifice for the lateral nozzle presents the problem that, with the air flap opened, air is supplied to the foot space to only an insufficient extent when the air supply to the lateral nozzles is not throttled on the outside at the lateral nozzles by flaps present there. This insufficient air supply to the foot space becomes noticeable particularly when the heating is in operation.
Although such insufficient ventilation of the foot space could possibly be rectified by making the orifice cross-section of the first air-outflow orifice to the lateral nozzle substantially smaller than the orifice cross-section of the second air-outflow orifice for ventilating the foot space, such a reduction in cross section is nevertheless forbidden on account of the air requirement of the lateral nozzle in the event of maximum ventilation or cooling of the passenger compartment.
An object on which the present invention is based is to provide an air-distributor box in which there is no need for the outer throttling of the lateral nozzle for the purpose of a sufficient heating of the foot space when the air flap is open.
The foregoing object has been achieved according to the present invention by providing that the first air-outflow orifice is associated with a throttle diaphragm arranged to control an orifice cross-section of the first air-outflow orifice, and the throttle diaphragm and air flap are positively coupled such that the throttle diaphragm maximally throttles the orifice cross-section of the first air-outflow orifice in the open position of the air flap allowing a full air stream to the second air-outflow orifice and exposes the orifice cross section of the first air outflow orifice completely in a closing position of the air flap shutting off the air stream to the second air-outflow orifice.
An advantage of the air-distributor box according to the present invention is that, as a result of the throttle diaphragm at the air-outflow orifice to the lateral nozzle and its coupling to the air flap for ventilating the foot space, when the air flap is opened for ventilating the foot space, the orifice cross-section of the air outflow orifice to the lateral nozzle is automatically throttled correspondingly. Thus, a sufficient ventilation of the foot space is ensured, without the need for additional manipulations on the lateral nozzle. When the air flap is closed, the throttle diaphragm exposes the first air-outflow orifice completely, and when it is opened completely the orifice cross-section of the first air-outflow orifice is reduced to the maximum extent. Between these two end positions, i.e., "foot-space air flap closed" and "foot-space air flap fully open", a continuous closing of the air-outflow orifice by the throttle diaphragm is obtained for the supply of air to the lateral nozzle.
In one preferred embodiment of the present invention, the throttle diaphragm is configured so that maximum throttling does not create a total air shut-off relative to the lateral nozzle, but there is still a residual cross section for a minimum air flow in the air-outflow orifice. This residual cross-section is preferably selected so that the residual air stream corresponds approximately to that which would flow out via the lateral nozzle in the event of an outer throttling of the lateral nozzle to less than half.
A simple constructive implementation of the throttle diaphragm is achieved by using as a throttle diaphragm a plate-shaped rotary slide which is rotatable parallel to the plane of the first air-outflow orifice about a pivot axis oriented at right angles thereto. The rotary slide preferably has the form of a circular segment, and its pivot axis is arranged near one edge of the first air-outflow orifice of rectangular configuration. If the first air-passage orifice is, for example, made square and the form of a segment of a circle of the rotary slide has a segment angle of approximately 90.degree. and a circle radius which is a little smaller than the side length of the square air-outflow orifice, then approximately the above-defined maximum throttling of the air passage cross-section in the first air-outflow orifice is achieved.
A coupling rod invention is used for the positive coupling of the throttle diaphragm and air flap, which coupling rod, with the pivot axes of the throttle diaphragm and air flap oriented in parallel, is articulated on the air flap and on the throttle diaphragm of joint axes parallel to the pivot axes.