Fluid handling – Systems – Multi-way valve unit
Patent
1991-02-21
1993-03-23
Cohan, Alan
Fluid handling
Systems
Multi-way valve unit
1376252X, 91375A, B62D 5083
Patent
active
051955598
DESCRIPTION:
BRIEF SUMMARY
The invention is concerned with a rotary slide valve, especially for auxiliary-power steering devices for motor vehicles, with a rotary slide that is rotatable opposite a control bushing. A pressure agent is directed from a pressure agent source to and from a servomotor with such a rotary slide valve. For that purpose, the control bushing and the rotary slide have longitudinal grooves that work together. The guiding edges of the guiding longitudinal grooves of the control bushing and the rotary slide, working together, are always placed parallel with each other. Such a rotary slide valve is known from DE-PS 33 03 063.
In such a rotary slide valve, certain tolerances in the width of the guiding grooves of the control bushing and the rotary slide and the dividing of the guiding edges occur in the usual manufacturing processes. Therefore, in the completely assembled rotary slide valves, the valve characteristic curves lie within a field of tolerance whose width does not satisfy the desire for uniform, even steering.
The object of the invention is to improve a known rotary slide valve so that the width of the valve's characteristic curve's field of tolerance is reduced to a minimum. Simple manufacturing and assembling processes are to be used in accomplishing that object.
The achievement of the object consists, above all, in positioning the guiding edges of the guiding longitudinal grooves of the control bushing and the rotary slide conically with respect to each other longitudinally. In assembling control bushings and rotary slides made to be placed in that way, they are first pushed axially, in relation to each other, into a position in which the valve's characteristic curve occupies a certain position in the field of tolerance of the valve's characteristic curve. Then the control bushing and the servo-piston are fastened in their axial positions.
If the control bushing and the rotary slide are centered on each other by a torque rod, the two parts are fastened together firmly over the torque rod after their exact axial position has been located. This is accomplished by drilling holes in the control bushing and the rotary slide and pinning them to the torque rod.
It is desirable for the guiding grooves of the control bushing to be manufactured by a non-cutting process, such as cold extrusion or round kneading. However, a final processing by grinding is also possible.
By means of the construction of the two parts of the rotary slide valve according to the invention and the assembling process, rotary slide valves can be produced whose valve characteristic curves lie within a very narrowly limited field of tolerance.
In the following, the invention is described in greater detail with the help of an embodiment that is shown in the drawings.
FIG. 1 shows the longitudinal section through the rotary slide valve of the invention along the line I--I in FIG. 2.
FIG. 2 shows a cross section through the rotary slide valve of FIG. 1.
FIG. 3 shows a partial longitudinal section along the line III--III in FIG. 2.
FIG. 4 shows a valve's characteristic curve with the field of tolerance.
The rotary slide valve consists essentially of a control bushing 1 in which a rotary slide 2 is carried rotatably. The control bushing 1 has guiding longitudinal grooves 3 and 4 in its interior that are provided with guiding edges 5 and 6. The guiding longitudinal grooves 3 and 4 are connected with the two surge chambers of a servomotor (not shown).
The rotary slide valve 2 has guiding longitudinal grooves 7 and 8 that are connected with a power-steering pump (not shown) and a tank (not shown). The guiding longitudinal grooves 7 are provided with guiding edges 10 and 11 that work with the guiding edges 5 and 6. The guiding edges 10 and 11 are provided with guiding chamfers with which a certain shape of the valve characteristic curve of the rotary slide valve can be obtained.
The guiding edges 5 and 6 of the guiding longitudinal grooves 3 and 4 of the control bushing 1 run to each other conically. The guiding edges 10 and 11 of the guiding long
REFERENCES:
patent: 3867075 (1975-02-01), Horst
patent: 4106883 (1978-08-01), Hansen
patent: 4561516 (1985-12-01), Bishop
patent: 4858712 (1989-08-01), Neff
Breitweg Werner
Schanzel Rainer
Cohan Alan
Zalkind Albert M.
LandOfFree
Rotary slide valve for auxiliary-power steering devices for moto does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rotary slide valve for auxiliary-power steering devices for moto, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rotary slide valve for auxiliary-power steering devices for moto will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1345533