Throttle valve housing formed of molded plastic

Details Throttle valve housing formed of molded plastic Throttle valve housing formed of molded plastic

1995-04-07

1996-11-19

Nelli, Raymond A.

Internal-combustion engines

Engine speed regulator

Specific throttle valve structure

F02D 908

Patent

active

055752560

DESCRIPTION:

BRIEF SUMMARY
The invention relates to a moulding consisting of plastic, in particular produced by the injection-moulding process, for example a throttle-valve housing, having a wall which with an inner wall surface bounds a cavity.
In the case of many mouldings, there is the requirement that the inner wall surface of the cavity must be dimensionally stable, i.e. must not change its shape and its dimensions. This is necessary, for example, whenever the effective throughflow cross-section of this cavity is to be variable by a throttling member located therein. For example, this is the case with throttle valves, such as are used in air intake pipes of internal combustion engines in motor vehicles. In such valves there is in a cross-section of the cavity, which forms part of the air intake pipe, a disc-shaped throttling member mounted such that it can swivel about a throttle-valve spindle, by the swivelling of which throttling member the throughflow cross-section of the air-intake pipe can be varied from maximum to complete shut-off.
It is already known to form such throttle-valve housings, which form part of the air-intake pipe and receive the throttle valve, from an aluminium moulding. However, such throttle-valve housings are expensive, on the one hand because of the relatively expensive production material, but in particular because of the finishing work required. After producing the blank, the inner wall surface must namely be machined by milling or drilling to achieve the required diameter and must be ground for producing the fitting surfaces. Furthermore, the bearing bores for the throttle-valve spindle of the swivelling disc-shaped throttling member have to be correspondingly machined, and for attaching additional parts, such as, for example an idling-speed governor or potentiometer, the connections to the air-intake pipe and threaded bores have to be cut.
Recently, the air-intake stub located upstream of the throttle-valve housing has often been produced from plastic. If in this case the throttle-valve housing consists of aluminium, relatively heavy in comparison with plastic, undesired vibrations of this throttle-valve housing occur.
It has therefore already been proposed to produce the throttle-valve housing likewise from plastic, to be precise by the injection-moulding process. Such throttle-valve housings consisting of plastic have the advantage that they are lighter than aluminium housings, that the production material is cheaper and that inserts, for example inserts provided with threaded bores or inserts designed as rolling-contact bearings for the mounting of the throttling member, can be pressed into openings formed during the injection-moulding operation, so that finishing can be reduced to a minimum. The disadvantage of such throttle-valve housings consisting of plastic is that they shrink during and after the injection-moulding and distort after demoulding and that, furthermore, they have poor dimensional stability under the effect of temperature and force. It must be taken into account here that the engine compartment of a motor vehicle, and therefore also the throttle-valve housing, is subject to large temperature fluctuations, since on the one hand extremely low temperatures can occur when the motor vehicle is left parked outside in the winter and on the other hand temperatures in excess of 120.degree. C. can occur during the operation of the motor vehicle, in particular on hot summer days, and after the engine has been switched off. For these reasons, dimensional stability of the inside surface of such throttle-valve housings consisting of plastic is not insured. Such dimensional stability is necessary, however, in order that every position of the swivelling throttling member corresponds to a precisely defined throughflow cross-section and, in particular, in order that a minimum, precisely defined residual gap or complete shutting off in an end position of the throttling member is possible. For reasons of environmental protection and to reduce fuel consumption, nowadays very low idling speeds of th

REFERENCES:
patent: 4356801 (1982-11-01), Graham
patent: 4561158 (1985-12-01), Johnson et al.
patent: 4909212 (1990-03-01), Minowa et al.
patent: 5146887 (1992-09-01), Gluchowski et al.

Affiliated with

Also associated with

Rating

Throttle valve housing formed of molded plastic does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Throttle valve housing formed of molded plastic, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Throttle valve housing formed of molded plastic will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-533705