Fluid-pressure and analogous brake systems – Multiple fluid-receiving devices – Multiple motors
Patent
1985-07-18
1987-06-02
Reger, Duane A.
Fluid-pressure and analogous brake systems
Multiple fluid-receiving devices
Multiple motors
303 22R, B60T 822
Patent
active
046697888
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a vehicle having at least one load conscious valve for controlling the brake pressure applied to the rear brakes of the vehicle.
It is well known to provide a vehicle with one or more brake pressure reducing valves which operate, under certain conditions, to provide a brake pressure to the rear brakes which is lower than the pressure applied to the front brakes. Such pressure reducing valves may be made load conscious whereby the characteristics of the valve are varied in accordance with both static and dynamic loading of the vehicle. Vehicle loading may be sensed by incorporating the valve as a load bearing component in a suspension assembly which interconnects the sprung and unsprung parts of the vehicle, whereby the whole or a significant part of the load transmitted from the sprung to the unsprung parts of the vehicles is applied to the valve. Such an arrangement is shown in GB No. 1557006A. ln the alternative, the valve may be separate from the suspension and may be provided with a sensing spring which applies to the valve a force determined by the rclativc position of the sprung and unsprung parts of the vehicle. It is with this type of valve that the present invention is concerned. Since the relative position of the sprung and unsprung parts is dependent on vehicle loading, such an arrangement does render the valve load conscious. However, no significant part of the vehicle load is transferred from the sprung to the unsprung part of the vehicle by the valve since the sensing spring is light and only serves to sense the position of the unsprung part relative to the sprung part. A prior art arrangement of this general type is shown in GB No. 1252700A.
While valves of the non-load bearing type have various advantages which will be known to those skilled in the art, prior art valves of this type have suffered from a disadvantage, described in more detail below, whereby under contain operating conditions the pressure applied to the rear brakes is considerably less than optimum. The present invention provides a vehicle having a valve of this general type with substantially improved performance in this respect.
According to the present invention there is provided a vehicle comprising a sprung part supported on a plurality of unsprung parts by way of a plurality of suspension assemblies; at least one brake pressure reducing valve having an inlet connected to a source of hydraulic brake fluid, an outlet connected to a rear brake operating cylinder, and a control piston which moves in a first direction to interrupt communication between the inlet and the outlet; a bias spring which applies to the control piston a substantiallY constant force tending to move the control piston in the said first direction; and a positioning sensing spring which at all times when the vehicle is in use applies to the control piston a force in opposition to that of the bias spring, the force applied by the position sensing spring being determined by the relative position of the sprung and unsprung parts of the vehicle.
In the preferred embodiment of the invention the force applied by the position sensing spring is determined by the relative position of the vehicle body and the rear axle or a rear unsprung suspension arm. The force applied to the control piston by the sensing spring increases as the sprung and unsprung parts move nearer to each other, as will occur when load is added to the vehicle, and decreases when, due to weight transfer during braking, the sprung and unsprung parts move away from each other.
The invention will be better understood from the following description of the prior art and of a preferred embodiment of the invention, reference being had to the accompanying drawings, wherein:
FIG. 1 shows schematically a typical prior art valve;
FIG. 2 is a graph showing the characteristics of the valve of FIG. 1;
FIG. 3 shows schematically a valve for use in an embodiment of the invention; and
FIG. 4 is a graph showing characteristics of the valve of FIG. 3;
FIG. 5 is a schematic view of a X-s
REFERENCES:
patent: 3503657 (1970-05-01), MacDuff
patent: 3866984 (1975-02-01), Seip
patent: 3901561 (1975-08-01), Seip
patent: 3909074 (1975-09-01), Seip
patent: 4411476 (1983-10-01), Koshimizu
Lucas Industries Public Limited Company
Reger Duane A.
LandOfFree
Vehicle with load conscious brake pressure reducing valve does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Vehicle with load conscious brake pressure reducing valve, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vehicle with load conscious brake pressure reducing valve will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-608295