Electrohydraulic pressure control mechanism

An electrohydraulic pressure control mechanism, with electromagnetically controllable hydraulic valves arrayed on a valve housing, with coils which have some of their parts overhanging the valve housing, and the parts being equipped with contact elements. A molding box enclosing the coils and the contact elements, with the molding box or part thereof being suitable for installation of an electronic controller or parts of terminals for such. The molding box featuring cavities extending from its set-down surface on the valve housing to the far outer surface of the molding box; and the cavities taking on the form of lead-through opening in the proximity of coils. This assures a simplified attachment of coil casings to the valve domes.

TECHNICAL FIELD 
The invention refers to an electrohydraulic pressure control mechanism, and 
more specifically to a brake retarder pressure control mechanism. 
BACKGROUND OF THE INVENTION 
An electrohydraulic pressure control mechanism of generic designation is, 
for instance, described in the international publication WO 92/12878. 
Here, aside from the commonly known modular assembly of the valve housing, 
the lid is sectioned by way of a flat panel support element. This design 
serves the purpose of accommodating an electronic regulator or parts 
thereof and, secondarily, it establishes an electric connection between 
the electronic regulator and the overhead contact elements of the 
electromagnetic valves. The lid, along with the coils of the 
electromagnetic valves, is attached to the valve domes of the valve 
housing. Insert contacts lock to bring about an electric connection 
between the contact elements and the electronic or electric components now 
integrated in the lid. Recommended fastening of the coils to the support 
element is achieved by the use of elastic mounts, as there are springs, to 
embed the coils into an elastic molding box. However, the implement of an 
elastic molding box proves to be unduly cumbersome in terms of the 
required task. 
It is the object of the innovation to improve the conventional state of 
technology pressure control mechanism. The goal is to achieve a simplified 
coil configuration and to arrive at a compact, yet functionally optimal 
coil arrangement to harmonize with the support element. Additionally, the 
invention provides ease of manufacture and maintenance, with differing 
thermal expansions of assembly components and their respective tolerances 
being compensated for in a stress-free fashion. 
It is proposed to have the molding box contain cavities fully extending 
from the mold box's set-down surface on the valve housing to the mold 
box's surface farthest removed from the valve housing and which, in 
proximity of the coils, appear as lead-through openings.

DETAILED DESCRIPTION OF THE DRAWINGS 
FIG. 1 shows a side projection of the pressure control mechanism with a 
sketch of its basic components. The longitudinal section shown extends 
along a valve row's valve dome axis. For emphasis on the coil casing 7, 
the intersection in proximity of the outer right electromagnetic valve has 
been shifted to molding box 1 (also compare subsequent FIG. 2). Molding 
box 1, fastened onto valve housing 3, consists of a high-viscosity plastic 
substance which, through a device, sprays or laminates around coils once 
the strip conductors (tracks) 10 and/or printed circuits are soldered to 
the contact elements 11 above coils 4. The plastics of the molding box and 
the plastics of the coil casing thus protect the strip conductors 10 and 
coils 4. To accommodate valve dome 6, molding box 1 provides 
liberally-proportioned lead-throughs to facilitate a sufficient radial 
tolerance compensation between molding box 1 and valve dome 6--in order to 
have molding box 1 (containing coils 4) fit easily over valve domes 6 to 
come to rest on valve housing 3. The lead-through openings 5 in molding 
box 1 are proportioned so that coil casing 7, opposite coils 4, can be 
comfortably fit onto valve domes 6 and, for instance, can be secured with 
a gripper ring 12. For this purpose, coil casing 7 need not be totally 
enclosed; instead, side recesses 9 lend coil casing 7 an open profile in 
the form of an U-leg. Within contact range of valve dome 6, the coil 
casing 7 takes on the shape of a bush 8, assuming the function of a yoke 
ring. Hence, following installation of molding box 1, and coil casing 7 on 
valve housing 3 over magnetic core 13, the magnetic circuit is closed. 
Cavities 2 and lead-through openings 5 on molding box 1 contribute to 
weight and material reductions and bridge varying mechanical and thermal 
tolerances of components between valve housing 3 and molding box 1 in a 
stress-free fashion. Each coil casing 7 of valve housing 3 is governed 
exclusively by its respective valve dome and exhibits sufficient radial 
play relative to coils 4 and molding box 1 to guarantee at any 
time--regardless of assembly component tolerances--proper coil location on 
the valve housing. In FIG. 1 the insert terminal 14 is integrally sprayed 
or laminated with molding box 1, affording a relatively easy electric 
connection to the periphery. 
FIG. 2 shows a top view of the pressure control mechanism with the molding 
box 1 and part of the electromagnetic valves visible following 
installation on valve housing 3. The strip conductors (tracks) embedded in 
molding box 1 are indicated as in dash lines. It refers to a pressure 
control mechanism with electromagnetic valves, divided in 2 rows of four 
across. The magnetic valve row, shown in longitudinal section in FIG. 1 
represents closed hydraulic valves in an electromagnetically unexcited 
basic position, which is identical to the valve row in FIG. 2. The 
opposite valve row represents open hydraulic valves in an 
electromagnetically excited basic position. The depicted hydraulic valves 
in their entirety can be connected to the wheel brakes and brake pressure 
initiator of a slip-controlled braking system. This takes place over 
several hydraulic brake pressure lines and runoff lines not visually 
specific represented here. Easily recognizable are the liberally designed 
elongated lead-through openings 5 in molding box 1; also coil casings 7 
and their--in top view--flattenings (symmetrically distributed over 
respective coil circumferences) which conform to recesses 9, in order for 
the filler mass of coil 4 to become visible in lead-through openings 5. 
The filler mass of coils 4 is enclosed segmentally by the material of 
molding box 1. The top view also reveals the dash-lined wall thickness of 
bush 8, constituting the yoke ring. Bush 8 is a single-piece connection 
with the steel-made coil casing 7, extending along the valve dome walls. 
Also shown as a dash-line is the wall thickness of the bifurcated or 
U-shaped crimped legs of coil casing 7. 
In summation it can be stated that the invention reduces the requirement 
for filler mass and/or sealer to a minimum, eliminating the task of 
extensive spraying or reforging of coils 4. Cleaning, and problems of 
deformation are similarly reduced to a minimum during manufacture. Molding 
box 1 and the sealer of coils 4 form a simple-to-produce entity, while the 
coils 4 (on account of the sealer) firmly connect to molding box 1. 
Contact elements 11 on strip conductors 10 are embedded within the molding 
box 1. By use of simple-to-manufacture coil casings which are inserted 
(after installation of molding box 1 on valve housing 3) into valve domes 
6 by way of lead-through openings 5, the proper positioning--independent 
of component tolerances--of coils 4 on valve domes 6 is achieved. The 
horizontal and vertical distance of coils relative to valve domes 6 can be 
liberally proportioned, simplifying the installation of the electrical 
assembly on valve housing 3 considerably.