GB2303205A - Air vent for motor vehicles - Google Patents

Abstract

An air vent 30 has an air grill 33 to direct the supply of air 32-38 within the passenger compartment 35 of a motor vehicle. An air duct 39 carries a flow of air towards the grill 33 which is formed from a set of parallel vanes which define channels 42-47 for directing the air. The vanes are rotatable about a common axis 48 to vary the direction of the air supplied by the vent. Each end vane 53,54 is supplied with a lip 51,52 to restrict the flow of air through an end channel 42,47 when that flow would be directed towards an inner wall 49,59 of the duct. This allows the remaining air flows to be substantially undeflected. A second set of rotatable vanes at right angles to those in the air grill may be provided, with the endmost vanes of the second set also having air spoilers or lips.

Description

Air Vent The present invention relates to an air vent for a motor vehicle passenger compartment, and in particular to a barrel air vent with an air spoiler to help direct the flow of air at the extremes of movement of the vent.

Air vents for a motor vehicle passenger compartment generally have adjustable louvres, vanes or other means to direct the flow of air supplied through an air duct.

Often, the adjustment may be made independently in two orthogonal directions. At the extremes of adjustment, the louvres nearest the duct wall may not direct the air efficiently, particularly if the louvres are recessed and directed air impinges on and is deflected by the wall of the duct.

According to the present invention, there is provided an air vent for directing the supply of air within the passenger compartment of a motor vehicle, the air vent comprising an air duct for carrying a flow of air towards a downstream portion of the duct within which is housed a set of substantially parallel vanes defining therebetween channels for directing air into the passenger compartment, the vanes being movable to direct air supplied by the vent, wherein a vane has a lip to restrict the flow of air through a channel when that flow would be directed towards a wall of the duct.

It is pry'arable if the restriction of the flow through the chaw eel increases progressively as the vanes are rotated, so that there is no sudden change in the supply of air from the air vent, and also so that the degree of restriction can be matched to the degree to which the air flow would otherwise impinge on the inner wall of the duct.

In a preferred embodiment of the invention, the air vent has vanes which are rotatable about a common pivot axis in which case the set of vanes may be held in a fixed orientation with respect to each other, for example in a barrel or cylinder fixture. The pivot axis may advantageously be provided at a mid point through the set of vanes, in which case as the set is pivoted, some of the vanes may rotate outwards from the duct, and the others may rotate inwards into the duct.

In order to maximise the air flow to the passenger compartment, it is preferred if the lip does not substantially restrict the flow of air through the channel when that flow is not directed towards a wall of the duct.

The lip may be provided at an upstream end of the channel, in which case the lip may act as an air dam, reducing the flow of air entering the channel.

Since the pair of vanes closest to a duct wall will generally be the ones which define a channel which may be directed at the wall, it is advantageous if the vane next to the inner wall of the duct is provided with the lip.

In general therefore, two vanes may have a lip, with each vane at an opposite side of the set of vanes. Other vanes further from the wall may also be provided with a lip if these vanes would otherwise direct air at the wall.

It is often desirable for motor vehicle air vents to be adjustable to vary the direction of the air supply entering the passenger compartment in more than one plane.

Therefore the air vent may have towards the downstream portion of the duct a second adjustable set of substantially parallel vanes at an angle to the first set of vanes and defining therebetween channels for directing air into the passenger compartment. The second set is preferably adjustable by rotating the vanes, which may be behind or in front of the first set of vanes with respect to the direction of the air flow. Alternatively, the two sets of vanes may be interlacing with, for example, the second set riding on the first set so that the first set of vanes provides a primary independent adjustment and the second set of vanes provides a secondary adjustment dependent on the first adjustment.

A vane from the second set of vanes may also have a lip to restrict the flow of air through a channel when that flow would otherwise be directed towards an inner wall of the duct.

In order to have a wide and easily varied adjustment range for the direction of air leaving the air vent, the first and second sets of vanes may have adjustments which are orthogonal to each other.

The air vent may advantageously be formed from a plastics material or materials with, for example, the duct being formed from a tubular extrusion of PVC, and the set of vanes being formed in ABS from an injection mould.

The invention will now be described further by way of example with reference to the accompanying drawings, in which: Figure 1 is a side view in cross section of a prior art barrel air vent with a set of vanes inside the downstream end of an air duct, showing the air flow through the air vent at one extreme of adjustment; Figure 2 is a side view in cross section through a barrel air vent according to the invention, showing the air flow through the vent at one extreme of adjustment; and Figure 3 is a side view in cross section through the barrel air vent of Figure 2, showing the air flow through the vent at a median adjustment.

Referring to Figure 1, the prior art air vent 1 is set inside a component 6 which may, for example, be an automobile instrument panel. The vent comprises an air duct 2 towards a downstream end of which is housed a plastic air grill 3 composed of a set of parallel vanes 4 held between end supports, one of which 7 is visible in the drawing. The air grill 3 is pivotally mounted about a central axis within the terminal portion of the duct 2, and may be manually adjusted by a passenger or driver to direct the supply of air. The two pivot points, just one of which 8 may be seen, are in the gap between the end support 7 of the grill 3 and duct wall. The air grill may rotate between two end stops 9,10 which protrude from the inner wall of the duct 2.

The downstream portion of the duct 2 may be a terminal portion, or if the duct provides air to more than one air vent or other outlet, then the downstream portion may be one of several branches in the duct.

A flow of air along the duct 2 passes through the grill 3 into the passenger compartment 5, as shown schematically by the arrows. Reference numerals 12 to 17 represent six streams of air that have been directed by the six grill channels 22-27 between the vanes 4, and reference numerals 11 and 18 represent two streams of air than have passed through two peripheral channels or gaps 21,28 between the air grill 3 and the walls of the duct 2.

The air grill 3 is shown in an extreme adjustment so that the air flow entering the passenger compartment is directed downwards. Because the grill rotates about the central pivot point 8, the lower half of the grill rotates inwards and the upper half of the grill rotates outwards with respect to the face of the surrounding component 6.

As can be seen from Figure 1, the end air flow 12 through the lowermost grill channel 22 is first directed towards the duct end wall section 29, and is then deflected to flow roughly parallel to this wall until the flow 12 enters the passenger compartment. (The term 'deflected' is used throughout the description to mean 'directed away from the intended direction'.) This effect may be increased by the peripheral air flow 11 between the air grill 3 and the end wall section 29, although generally both peripheral air flows 11,18 are weaker than the grill air flows 12-17, and so are indicated by dashed rather than solid arrows. These peripheral flows 11,18 may be reduced by appropriate matching of the contour of the duct wall to the movement of the air grill in order to reduce the size of the peripheral gaps 21,28.

The end stops 9,10 do not project sufficiently from the wall of the duct 2 to have a significant effect on the air flows 11-18.

Once the end air flow 12 has been deflected, it in turn will act against the adjacent air flow 13, and deflect this flow upwards, and since each deflected air flow progressively affects the path for an adjacent flow, all the air flows 12-17 through the channels 22-27 will be deflected upwards from the path intended by the user.

The same effect occurs at the other extreme of adjustment, when the upwards directed air flow is deflected downwards from the intended path.

The result of this deflection is that the overall adjustment range of the air vent is decreased, and while the adjustment of the air flow may not be affected over the centre portion of the adjustment range, the intended path of the air flow becomes increasingly affected by the deflection towards the extremes of the adjustment range, with also a consequent apparent loss of sensitivity to adjustment over these ranges.

The embodiment of the invention shown in Figure 2 reduces these adverse effects. The air vent 30 is again set in a motor vehicle component 36 and comprises an air duct 39 and an air grill 33 rotatable between pivots 48 over an adjustment range limited by a central end stop 30.

The air grill 33 differs in construction from the air grill of Figure 1 by the addition of two air spoilers or lips 51,52 which are integral with and project from the end vanes 53,54 in towards the air duct 39. Each lip 51,52 is angled with respect to the vane to protrude towards a plane passing through the central portion of an end channel 42,47.

The air grill 33 is illustrated in the extreme downwards setting in which position the lower lip 52 has rotated upwards into the air flow to restrict the entry of the end air flow 32 into the lowermost channel 42. As a result, the end air flow 32 is weak, as indicated by the dashed arrow. This residual end air flow is directed at the duct wall section 49, and is deflected parallel to this wall as it enters the passenger compartment 35. However, this deflected end flow 32 is not strong enough to deflect the adjacent flow 33 to a significant degree, and so the air flows 33-38 from the air vent enter the passenger compartment 35 substantially undeflected and in the direction intended by a passenger or driver.

The efficiency of this arrangement is further increased by the use of two air stops 55,56 which restrict the gap, and hence the air flow, between the end vanes 53,54 of the air grill and the walls of the duct.

When the air grill 33 is set at the other extreme of adjustment, the other lip 51 produces an effect similar to that described above, restricting the end air flow 37 that would otherwise impinge on the duct end wall 59.

This results in a substantially undeflected upwards air flow.

At these two extremes of adjustment, one of the lips 51,52 projects substantially at right angles to the air flow within the duct, acting as an air dam to hold back the flow of air entering an endmost channel'42,47. 42,47. As illustrated in Figure 2 by numeral 31, an air flow that is held back will swirl turbulently backwards from the lip 51, and mix with the other air flows. Although the resultant air flow within the duct may become quite complex, and can only be represented conceptually by the air flow arrows as drawn, the overall effect will be to reduce tne air entering the channel 42, and so reduce the total air leaving the duct through the air grill 33 at these extremes of adjustment. The total volume of the air flow, however, may not be noticeably impeded, but if a greater flow is required, then this may be provided by a higher fan setting.

Referring finally to Figure 3, the air vent 60 is illustrated with the adjustable air grill 63 set at the centre point of the adjustment range. The main air flows 62-67 pass through all the channels 72-77 in the air grill. The lips 81,82 on the end vanes 83,84 both project in towards the air flows within the duct 69 at a maximum angle of about 300 to these air flows. The end air flows 62,67 can therefore spill over these lips into the end channels 72,77. The lips 81,82 and air stops 85,86 may cause some turbulent flow nearest the duct walls, as illustrated by the peripheral air flow 68, but the major portion of the air flow, even those flows 61 close to the duct walls, will pass through the air grill 63 substantially unaffected by the lips 81,82 on the endmost vanes 83,84.

An air vent as described above may also be provided with a second set of rotatable vanes at right angles to those in the air grill as illustrated, to provide an orthogonal adjustment of the air flow into the passenger compartment.

Such an arrangement of orthogonal vanes may be provided behind the air grill. Alternatively, the first and second sets of vanes may be interlaced, with all the vanes of the second set being pivotable about individual parallel axes.

The endmost vanes of the second set of vanes may also be provided with air spoilers or lips according to the invention to minimise the deflecting effect of an air flow incident on the duct side walls.

As will be appreciated from the above discussion, the scope of the invention is not restricted to the specific embodiment as shown in the drawings, in which all the vanes are held in a fixed orientation with respect to each other and rotatable about a common central axis, but extends equally to other arrangements of vanes, for example, those in which the vanes are each pivotable about individual axes.

Claims (11)

Claims

1. An air vent for directing the supply of air within the passenger compartment of a motor vehicle the air vent comprising an air duct for carrying a flow of air towards a downstream portion of the duct within which is housed a set of subostantially parallel vanes defining therebetween channels for directing air into the passenger compartment, the vanes being movable to direct air supplied by the vent, wherein a vane has a lip to restrict the flow of air through a channel when that flow would be directed towards a wall of the duct.

2. An air vent according to Claim 1, in which the restriction of the flow through the channel increases progressively as the vanes are rotated.

3. An air vent according to Claim 1 or Claim 2, in which the vanes are rotatable about a common axis.

4. An air vent according to any preceding claim, in which the lip does not substantially restrict the flow of air through the channel when that flow is not directed towards a wall of the duct.

5. An air vent according to any preceding claim, in which the lip is provided at an upstream end of the channel.

6. An air vent according to any preceding claim, in which the lip is provided on a vane next to the inner wall of the duct.

7. An air vent according to any preceding claim, including a second adjustable set of substantially parallel vanes at an angle to the first set of vanes and defining therebetween channels for directing air into the passenger compartment.

8. An air vent according to Claim 7, in which the second set of vanes is rotatable to vary the direction of the air supplied by the vent, and wherein a vane from the second set of vanes has a lip to restrict the flow of air through a channel when that flow would otherwise be directed towards an inner wall of the duct.

9. An air vent according to Claim 7 or Claim 8, in which the first and second sets of vanes adjust orthogonally the direction of the air leaving the vent.

10. An air vent according to any preceding claim, in which the air vent is formed from a plastics material.

11. An air vent substantially as described herein with reference to and as shown in the accompanying drawings.