U.S. patent application number 09/792434 was filed with the patent office on 2002-09-12 for valve system for the pre-engagement unit of a braking pressure modulator.
Invention is credited to Frank, Dieter, Homann, Peter, Kranz, Andreas, Meier, Dirk, Schreiber, Gerdt, Sieker, Armin, Wolff, Hans-Klaus.
Application Number | 20020124891 09/792434 |
Document ID | / |
Family ID | 7632534 |
Filed Date | 2002-09-12 |
United States Patent
Application |
20020124891 |
Kind Code |
A1 |
Frank, Dieter ; et
al. |
September 12, 2002 |
VALVE SYSTEM FOR THE PRE-ENGAGEMENT UNIT OF A BRAKING PRESSURE
MODULATOR
Abstract
A valve system for the pre-engagement unit of a vehicle braking
pressure modulator contains solenoid valves, which are controlled
by an electronic braking system. Pneumatic pressure is fed into a
brake cylinder on the vehicle wheels via a pressure regulating
channel of the pre-engagement unit. The solenoid valves are
configured as cartridge solenoid valves, so that assembly is
simplified, and utilization of elastic tolerance compensating
elements is unnecessary. A preferred embodiment includes three
cylinder bodies connected end-to-end with no increase in cylinder
diameter. This embodiment enables the use of identical armatures
and identical magnet coils for different valve types, such as
3/2-way solenoid valves or 2/2-way solenoid valves. Also, these
valves may be configured as normally open or normally closed, with
identical outside dimensions. As such, three cartridge solenoid
valves can be combined into a compact triple valve cartridge unit
that further simplifies the assembly process.
Inventors: |
Frank, Dieter; (Hannover,
DE) ; Schreiber, Gerdt; (Isernhagen, DE) ;
Homann, Peter; (Neustadt, DE) ; Sieker, Armin;
(Bielefeld, DE) ; Kranz, Andreas; (Wunstorf,
DE) ; Wolff, Hans-Klaus; (Springe, DE) ;
Meier, Dirk; (Seelze, DE) |
Correspondence
Address: |
Proskauer Rose LLP
Patent Department
1585 Broadway
New York
NY
10036
US
|
Family ID: |
7632534 |
Appl. No.: |
09/792434 |
Filed: |
February 23, 2001 |
Current U.S.
Class: |
137/596 |
Current CPC
Class: |
B60T 8/3675 20130101;
B60T 8/323 20130101; F15B 13/0814 20130101; B60T 8/362 20130101;
F15B 13/0835 20130101; F16K 31/0606 20130101; Y10T 137/5987
20150401; F15B 13/0857 20130101; F15B 13/0817 20130101; F16K
31/0627 20130101; Y10T 137/6011 20150401; F16K 27/003 20130101;
B60T 8/327 20130101; Y10T 137/86622 20150401; F15B 13/0821
20130101; B60T 15/181 20130101; Y10T 137/87217 20150401; F16K
31/0624 20130101; F15B 2013/004 20130101; Y10T 137/87169 20150401;
B60T 15/028 20130101 |
Class at
Publication: |
137/596 |
International
Class: |
F16K 011/22 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 26, 2000 |
DE |
100 09 116.4 |
Claims
26. A valve system having at least one solenoid valve for a
pre-engagement unit of a braking pressure modulator, comprising: a)
a one-piece housing, in which a square-shaped opening forms a first
forked flange and a second forked flange; b) a first bore in said
first forked flange and a second pocket bore in said second forked
flange, wherein a central line of said first bore is coaxial with a
central line of said second pocket bore; c) a magnet coil, having
an opening in the form of a straight circular cylinder through the
magnet coil, said magnet coil being designed so that it can be
positioned within said square-shaped opening of said housing; d) a
valve cartridge in the form of a cylinder with circular
cross-section, said valve cartridge being configured so that it can
be inserted into said housing, from said first bore in the
direction of said second pocket bore, wherein said magnet coil
positioned in said housing opening can only be displaced in an
axial direction; and e) at least one pressure medium terminal
connected to at least one of said forked flanges.
27. The valve system of claim 26, wherein said valve cartridge
comprises a straight stepped cylinder with circular cross-section,
and having one or more steps.
28. The valve system of claim 26, wherein the axial position of
said magnetic coil within said housing is fixed as a result of
fixing said valve cartridge after it has been inserted into said
housing.
29. The valve system of claim 26, further comprising additional
means for fixing the axial position of said magnet coil within said
housing with respect to said valve cartridge after it has been
inserted into said housing.
30. The valve system of claim 26, wherein said valve system
comprises a pre-engagement unit for a braking pressure modulator
for at least one pressure regulating circuit of an electronic
braking system.
31. The valve system of claim 30, wherein said preengagement unit
comprises: f) a first pneumatic inlet through which a supply
pressure is supplied to said pre-engagement unit; g) a second
pneumatic inlet through which a redundancy pressure is supplied to
said pre-engagement unit, said redundancy pressure being derived
from the braking pressure of said electronic braking system; h) a
pneumatic output terminal through which said pre-engagement unit is
connected to an air quantity augmenting valve system; i) an
electrically actuated valve system having pneumatic terminals which
are interconnected, and having electrical terminals which are
connected to the output terminals of an electronic control system;
and j) said electrically actuated valve system further comprising
three 2/2-way cartridge solenoid valves, each having a first and a
second pneumatic terminal.
32. The valve system of claim 31 wherein said pre-engagement unit
comprises a multiple valve cartridge unit comprising said three
2/2-way cartridge solenoid valves.
33. The valve system of claim 32 wherein said pre-engagement unit
comprises a head element connected to the individual cartridge
solenoid valves of said multiple valve cartridge unit.
34. The valve system of claim 32 wherein said cartridge solenoid
valves include magnet coils which are configured as multiple magnet
coil units which fit into the square-shaped opening of said housing
of said pre-engagement unit.
35. The valve system of claim 34, wherein said multiple magnet coil
units are assembled together as an extrusion coated multiple magnet
coil unit.
36. The valve system of claim 31, wherein said three 2/2-way
cartridge solenoid valves are connected in parallel to each
other.
37. The valve system of claim 31, wherein said three 2/2-way
cartridge solenoid valves are operated in a pulsating mode.
38. The valve system of claim 31, wherein said three 2/2-way
cartridge solenoid valves comprise: k) a first 2/2-way solenoid
valve is closed in its unactuated state and serves as an air
admission valve for the supply pressure to said pressure regulating
circuit; l) a second 2/2-way solenoid valve is open in its
unactuated state and serves as an air admission/exhaust valve for
the redundancy pressure to said pressure regulating circuit; and m)
a third 2/2-way solenoid valve is closed in its unactuated state
and serves as an air exhaust valve for said pressure regulating
circuit.
39. The valve system of claim 38, wherein: n) a first pneumatic
terminal of said first 2/2-way solenoid valve is connected to said
first pneumatic inlet of said pre-engagement unit, and a second
pneumatic terminal of said first 2/2-way solenoid valve is
connected to said pneumatic output terminal of said pre-engagement
unit; o) a first pneumatic terminal of said second 2/2-way solenoid
valve is connected to said second pneumatic inlet of said
pre-engagement unit, and a second pneumatic terminal of said second
2/2-way solenoid valve is connected to said pneumatic output
terminal of said pre-engagement unit; and p) a first pneumatic
terminal of said third 2/2-way solenoid valve is connected to said
pneumatic output terminal of said pre-engagement unit, and a second
pneumatic terminal of said third 2/2-way solenoid valve is
connected to a pressure sink.
40. The valve system of claim 26 wherein said pre-engagement unit
comprises: f) a first pneumatic inlet through which a supply
pressure is supplied to said pre-engagement unit; g) a second
pneumatic inlet through which a redundancy pressure is supplied to
said pre-engagement unit, said redundancy pressure being derived
from the braking pressure of said electronic braking system; h) a
pneumatic output terminal through which said pre-engagement unit is
connected to an air quantity augmenting valve system; i) an
electrically actuated valve system having pneumatic terminals which
are interconnected, and having electrical terminals which are
connected to the output terminals of an electronic control system;
j) a 3/2-way cartridge solenoid valve acting as a redundancy valve;
k) a normally open 2/2-way cartridge solenoid valve acting as an
air admission valve; and l) a normally closed 2/2-way cartridge
solenoid valve acting as an exhaust valve.
41. A valve system, having at least one solenoid valve cartridge
and an associated magnet coil, wherein said magnet coil actuates
said solenoid valve, and wherein said solenoid valve cartridge
comprises: a) three individual cylindrical bodies, designated as
first, second and third cylinder bodies in a predetermined assembly
direction, connected in series along their respective longitudinal
axes, wherein said three cylinder bodies are configured as either
circular round cylinders or circular round stepped cylinders; b)
said three cylinder bodies, each having a first end and a second
end in said assembly direction, are connected end-to-end so that
their respective cylinder diameters either decrease or remain
constant in said assembly direction; c) said second end of said
first cylinder body is connected to said first end of said second
cylinder body, and said second end of said second cylinder body is
connected to said first end of said third cylinder body in such
manner that said three cylinder bodies become an integral unit; d)
said first and second cylinder bodies are comprised of a
non-magnetic material; e) said third cylinder body comprises a
ferromagnetic material; f) said second cylinder body is hollow, and
contains an armature and an armature return device, wherein said
armature presses against said second end of said first cylinder
body when there is no current flowing in said magnet coil, and when
there is current flowing in said magnet coil, the resultant
magnetic field causes said armature to press against said first end
of said third cylinder body; g) said second end of said first
cylinder body representing a first valve lift stop of said
armature, and said first end of said third cylinder body
representing a second valve lift stop; h) said second end of said
first cylinder body is optionally equipped with either a sealing
seat or an armature stop; and i) said first end of said third
cylinder body is optionally equipped with either a sealing seat or
an armature stop.
42. The valve system of claim 41, wherein said solenoid valve
cartridge further comprises pressure medium terminals which are
connected to said solenoid valve cartridge, the type and number of
said pressure medium terminals being determined by the type of said
solenoid valve cartridge.
43. The valve system of claim 42 wherein said solenoid valve
cartridge has the following characteristics: j) said solenoid valve
cartridge is subdivided into first, second, and third cartridge
functional zones; k) said first cartridge functional zone extends
from said first end of said first cylinder body into that portion
of said second cylinder body which is located outside the influence
of said magnetic field; l) said second cartridge functional zone
extends from the end of said first cartridge functional zone
through that portion of said third cylinder body that is within the
influence of said magnetic field; m) said third cartridge
functional zone extends from the end of said magnetic field
influence to said second end of said third cylinder body; n) said
first cartridge functional zone including at least one pressure
medium terminal; and o) said third cartridge functional zone
optionally including an additional pressure medium terminal.
44. The valve system of claim 43, wherein said first and third
cartridge functional zones determine the axial position alignment
of said solenoid valve cartridge within said housing.
45. The valve system of claim 43 wherein: p) said armature includes
an elastomer insert to constitute a hermetically sealing valve seat
at said first valve lift stop; q) said armature includes a surface
at said second valve lift stop to form a non-hermetically sealing
metal-to-metal valve seat.
46. The valve system of claim 41 which comprises a part of a
pre-engagement unit for a braking pressure modulator for at least
one pressure regulating circuit of an electronic braking
system.
47. The valve system of claim 46 wherein said solenoid valve
cartridge comprises a 2/2-way cartridge solenoid valve.
48. The valve system of claim 47 wherein said solenoid valve
cartridge comprises a normally open solenoid valve cartridge.
49. The valve system of claim 47 wherein said solenoid valve
cartridge comprises a normally closed solenoid valve cartridge.
50. The valve system of claim 46 wherein said solenoid valve
cartridge is comprises as a 3/2-way cartridge solenoid valve.
51. The valve system of claim 46 wherein said armature is of
identical construction whether used for a 2/2-way cartridge
solenoid valve or for a 3/2-way cartridge solenoid valve.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a valve system for the
pre-engagement unit of a braking pressure modulator.
[0002] European patent application A1-0 893 636 discloses a
hydraulic solenoid valve, which utilizes an elastic means to
compensate for mechanical tolerances and heat expansion.
[0003] This known patent application shows a valve cartridge in
FIG. 1 (therein lectrovanne 1), which contains the elements of
mechanical actuation. This valve cartridge is inserted into an
opening of another component, which contains a magnet coil (therein
bobine 13).
[0004] When current flows in the magnet coil (13), a magnetic field
is created in the closed magnetic circuit, consisting of the parts
referenced in FIG. 1 as 14, 2, 7 and 9. This magnetic field causes
a force to be exerted upon a core (therein noyau 9), constructed in
the form of an armature. This force also acts, via a ram (therein
poussoir 16) connected to the core, upon a ball (therein bille 17),
which is not connected to the ram 16. The ball 17 is lifted up
against the force of a spring (therein ressort 22) from its sealing
seat (therein sige 18), causing the sealing seat 18 to be opened.
(When there is no current flowing in magnet coil 13, ram 16 is held
lightly, via a fixing spring, on the ball 17, as explained below,
whereas spring 22 is significantly stronger).
[0005] When sealing seat 18 is opened, the connecting channel
between the hydraulic inlet (therein 20) and the hydraulic output
terminal (therein 21) is opened. Therefore, the known solenoid
valve can be described as a normally closed 2/2-way solenoid
valve.
[0006] Since the known solenoid valve is made up of several
separate parts, a number of different work steps are required in
order to assemble it.
[0007] As shown in FIG. 1, valve cartridge 1 is inserted into an
opening of a bearing block 3, which is configured in the form of a
hydraulic block. The flange 2 is then placed over bearing block 3,
so that both flange 2 and valve cartridge 1 are attached to bearing
block 3 by the conical widening part 6. As such, a separate
component, consisting of bearing block 3, valve cartridge 1, and
flange 2, is pre-assembled, and is contained within the overall
hydraulic system.
[0008] In the electrical portion of the known solenoid valve (FIG.
1), a separate coil 13 is installed in a frame yoke 14, together
with the elastic blocks 33 and 34, and a plastic frame 24. A rubber
part 32 is then inserted between frame yoke 14 and the upper wall
29 of the valve housing. Then, the completed assembly, consisting
of frame yoke 14, coil 13, and elastic blocks 33 and 34, is
installed so that the terminals of coil 13 extend through the
contacting bores of the computer board 26.
[0009] The pre-assembled component, consisting of bearing block 3,
valve cartridge 1 and flange 2, is now screwed on to the valve
housing, such that elastic block 33 presses against flange plate 2.
This screw connection causes the participating elements in the
electrical portion to be placed under tension, which causes coil 13
to be placed in a longitudinal axial alignment relative to the rest
of the structure. The terminals of coil 13 are rigidly connected in
this longitudinal alignment; e.g., by soldering (27) to computer
board 26. As a result, the longitudinal alignment is made
permanent.
[0010] Permanent longitudinal fixing in conjunction with elastic
elements can be problematic, however, since a change in the force
relationships among the tolerance compensating elements (e.g., as a
result of temperature influences) does not take into account the
long-term behavior of elastic elements, or the influences caused by
forces of inertia due to oscillations.
[0011] The assembly of valve cartridge 1 also requires several work
phases. First, movable core 9 with ram 16 and the fixing spring (no
reference number is provided), are introduced into a tube 11, which
is used as an armature guide. Next, the inner part 7 is inserted
and attached with the spacer 10 via its smaller diameter upper part
8. Then, a sealing seat element (no reference number is provided)
is pressed into inner part 7 over the sealing ball 17, which
includes a guide (no reference number is provided). Finally, it is
necessary to assemble a pressure element (no reference number is
provided) for ball 17 and spring 22, which pre-stresses this
pressure element.
[0012] Typically, in the case of a braking pressure modulator
application, additional valve variants, such as a normally open
2/2-way solenoid valve, or a 3/2-way solenoid valve, must be used
in addition to a normally closed 2/2-way solenoid valve. However,
no mention of these valve variants is made in the cited patent
application.
[0013] It is therefore the object of the invention to provide a
valve cartridge system suitable for a pre-engagement unit of a
braking pressure modulator, in which the valve cartridge assembly
is facilitated, while at the same time eliminating the need for
elastic tolerance-compensating elements.
SUMMARY OF THE INVENTION
[0014] This object is achieved in a valve system for the
pre-engagement unit of a braking pressure modulator. The inventive
valve system comprises a one-piece housing, in which a
square-shaped opening forms a first forked flange and a second
forked flange. A first bore in the first forked flange is axially
aligned with a second pocket bore in the second forked flange. A
magnet coil, having an opening in the form of a straight circular
cylinder, is positioned within the square-shaped opening of the
housing. A valve cartridge, in the form of a cylinder with circular
cross-section, is inserted into the housing from the first bore in
the direction of the second pocket bore, so that the magnet coil
can only be displaced in an axial direction. In addition, at least
one pressure medium terminal is connected to at least one of the
forked flanges.
[0015] One advantage of the present invention is that the valve
cartridge can be assembled as a pre-testable component prior to
installation in the housing, and that it can be replaced with
another valve cartridge without adjustment.
[0016] In a further development of the invention, the valve
cartridge is a solenoid valve cartridge actuated by a magnet coil,
the solenoid valve cartridge comprising three individual
cylindrical bodies connected end-to-end with no increase in
cylinder diameter in an assembly direction so as to form an
integral unit. The second cylinder body is hollow and contains an
armature and an armature return device. The first and third
cylinder bodies are optionally equipped with either sealing seats
or armature stops. When there is no current flowing in the magnet
coil, the armature of the second cylinder body presses against
first cylinder body. Where there is current flowing in the magnet
coil, the resultant magnetic field causes the armature to press
against the third cylinder body.
[0017] A further advantage of the present invention is that
components of the same type, e.g., armatures, valve bodies, and
magnet coils, can be used interchangeably in different valve
systems, thus reducing manufacturing costs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The invention is described in greater detail below through
the example of embodiments shown in the drawings, wherein
[0019] FIG. 1 is a schematic of the pre-engagement unit of a
braking pressure modulator for a brake regulating circuit;
[0020] FIG. 2 shows a variant of a brake regulating circuit
pre-engagement unit;
[0021] FIG. 3 shows a valve design for a pre-engagement unit in
accordance with the circuit of FIG. 1;
[0022] FIGS. 4a-4f show several designs of an armature and its
integration in a magnet coil, in order to constitute a hermetically
sealing valve seat for the magnet when not under current, and a
non-hermetically sealing metal-to-metal valve seat for the magnet
when under current;
[0023] FIGS. 5a-5c show a valve cartridge, a housing, and a magnet
coil as separate components, and also shows the assembly of these
components in accordance with the invention;
[0024] FIG. 6 shows a variant of the valve cartridge assembly of
FIG. 5;
[0025] FIG. 7 shows the design and structure of a 3/2-way cartridge
solenoid valve in accordance with the invention;
[0026] FIG. 8 shows the design and structure of a normally closed
2/2-way cartridge solenoid valve in accordance with the
invention;
[0027] FIG. 9 shows the design and structure of a normally open
2/2-way cartridge solenoid valve in accordance with the
invention;
[0028] FIG. 10 shows a valve cartridge as in FIG. 7, with seals and
pressure medium terminals in accordance with the invention;
[0029] FIG. 11 shows a pre-engagement unit with a triple valve
cartridge unit and triple magnet coil unit in accordance with the
invention; and
[0030] FIG. 12 shows a section through a valve cartridge of the
pre-engagement unit in FIG. 11.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0031] An electronically regulated braking system (EBS) for trailer
vehicles has several brake regulating circuits working
independently of each other for the wheel brakes of the vehicle
(multi-channel system). A brake regulating circuit which represents
a pressure regulating channel for a wheel brake consists of a
pre-engagement unit made up of solenoid valves, an air-augmenting
relay valve, at least one brake cylinder for the wheel brakes, a
braking pressure sensor installed at a suitable location, and an
electronic control system which carries out the braking pressure
regulation.
[0032] The brake regulating circuit for the different channels of
the multi-channel system are of identical construction, so that the
description of one brake regulating circuit also describes the
other brake regulating circuits. The embodiment described herein is
based on the configuration of a basic variant for a trailer EBS
system of a semi-trailer having two axles. The trailer EBS system
is a 4S/2M system (four ABS sensors for four wheels and two
modulator channels for the wheel brakes of the left or right side).
The braking pressure regulation is therefore carried out per
side.
[0033] The EBS trailer vehicle is connected to an EBS tractor
vehicle via an electrical and via a pneumatic interface. The
electrical interface consists of the digital data interface
according to ISO 1199-2. The pneumatic interface consists first of
the supply channel which supplies air to the trailer, and secondly
of the braking line which is connected in the trailer to a trailer
braking valve. The trailer braking valve puts out a braking
pressure at its pneumatic output terminal which is derived from the
braking pressure transmitted in the pneumatic braking channel and
refers to it.
[0034] On the side of the EBS tractor vehicle, the supply and
control lines are connected to a trailer control valve. The
combination of the trailer control valve and the trailer braking
valve provides security against a tear-off condition as is known
from conventionally braked vehicle combination (tractor
vehicle/trailer vehicle). In case of such a tear-off condition, the
trailer braking valve also transmits a braking pressure in the
known manner.
[0035] Since the tear-off protection is made as stated in the same
manner as for a conventionally braked vehicle, the EBS trailer
vehicle can also be operated behind a tractor vehicle with a
conventional braking system. Therefore, the trailer braking valve
in the EBS trailer vehicle also contains the required functions of
a conventional trailer braking valve in conventional braking
systems, such as tear-off function and check valve.
[0036] In the trailer vehicle, the pressure transmitted by the
trailer braking valve serves for pneumatic, redundant braking in
case of an EBS failure. Furthermore, with the utilization of a
pressure sensor located in the trailer braking valve, it serves to
determine the electrical target value for the case that the EBS
trailer is operated with a conventional tractor vehicle, i.e., with
a non-EBS tractor vehicle. This transmitted pressure represents the
redundancy pressure.
[0037] A pre-engagement unit 1 and an air-quantity amplifying relay
valve 2 are shown in the pneumatic circuit of FIG. 1. The
pre-engagement unit 1 is provided with a first pneumatic inlet 4,
which is connected to a pressure supply (not shown), and with a
second pneumatic inlet 5, which is connected to the pneumatic
output terminal of a trailer brake valve (not shown) for the
transmission of redundancy pressure. A pneumatic output terminal 6
of the pre-engagement unit 1 is connected to an inlet 17 of the
relay valve 2. As described below, the solenoid valves of the
pre-engagement unit 1 are actuated through electrical control
cables from a control unit (not shown).
[0038] The pneumatic output terminal 18 of the relay valve 2 is
connected to the brake cylinders (not shown) of this brake
regulating circuit.
[0039] As shown in FIG. 1, three solenoid valves are provided in
the pre-engagement unit 1. A first solenoid valve 7 has a first
terminal 10 and a second terminal 11, a second solenoid valve 8 has
a first terminal 12 and a second terminal 13, and a third solenoid
valve 9 has a first terminal 14 and a second terminal 15.
[0040] The first terminal 10 of the first solenoid valve 7 is
connected to the first pneumatic inlet 4 of the pre-engagement unit
1, the first terminal 12 of the second solenoid valve 8 is
connected to the second pneumatic inlet of the pre-engagement unit
1, the second terminal 11 of the first solenoid valve 7 is
connected to the pneumatic output terminal 6 of the pre-engagement
unit 1, the second terminal 13 of the second solenoid valve 8 is
connected to the first terminal 14 of the third solenoid valve 9
and to the pneumatic output terminal 6, and the second terminal 15
of the third solenoid valve 9 is connected to a pressure sink
16.
[0041] The first solenoid valve 7 and the third solenoid valve 9
are made in the form of normally closed 2/2-way solenoid valves,
while the second solenoid valve 8 is made in the form of a normally
open 2/2-way solenoid valve.
[0042] The solenoid valves 7, 8, and 9 of the pre-engagement unit 1
serve to determine the pressure in the control chamber of the relay
valve 2. They are operated in a pulsating manner.
[0043] In its unactuated state, the second solenoid valve 8 is open
and serves to transmit the redundancy pressure from the second
pneumatic inlet 5 of the pre-engagement unit 1 into the control
chamber of the relay valve 2, when the other solenoid valves 7 and
9 are not actuated. This redundancy pressure valve thus serves as
an air admission valve as well as an exhaust valve for the control
chamber pressure. In the actuated (closed) state, the second
solenoid valve 8 cuts off the redundancy pressure from the control
chamber of the relay valve 2.
[0044] The first solenoid valve 7 is designed as an air admission
valve through its connection to the supply pressure at inlet 4, and
the third solenoid valve 9 serves as an exhaust valve for the
control chamber of the relay valve 2 through its connection to the
pressure sink 16.
[0045] The solenoid valves 7, 8 and 9, contrary to the series
connection of the valves according to the German patent document DE
42 27 084 A1, are connected in parallel to each other, so that they
can be actuated simultaneously.
[0046] Thus, for example, in case of full braking when the air
admission valve 7 is actuated to increase the pressure, the
redundancy valve 8 can remain at the same time in its non-actuated
(open) position. The redundancy pressure which increases during
full braking assists the admission of air into the control chamber
of the relay valve 2, so that the pressure build-up time is
shortened. During exhaustion of a brake, the redundancy valve 8 can
also remain in the non-actuated (open) state while the exhaust
valve 9 is actuated, so that the time required for the pressure
drop of the control-chamber pressure in the relay valve 2 is also
shortened.
[0047] Due to the identical nature of the magnet coils and the
armatures of the solenoid valves 7, 8 and 9, as mentioned below,
these valves present an identical switching behavior so that a
desired time response of pressure build-up and pressure drop in the
control chamber of the relay valve 2 can be obtained in a very
controlled manner by selecting suitable actuation times for the
solenoid valves.
[0048] FIG. 2 shows a pneumatic circuit variant somewhat different
from that of FIG. 1. The pre-engagement unit 1 of the brake
regulating circuit of a braking pressure modulator is known from
German patent 42 27 084 A1. A 3/2-way solenoid valve 21 acts as a
reversing valve between a supply pressure connected to a first
pneumatic inlet 4, and a redundancy pressure connected to the
second pneumatic inlet 5. This redundancy pressure is switched on
when the magnets are not actuated. The normally open 2/2-way
solenoid valve 22 is connected in series with the reversing valve
21, and connects the pneumatic output terminal 6 to the pressure
selected by the reversing valve 21. As such, valve 22 acts as an
air admission valve. The normally open 2/2-way solenoid valve 23
vents the pneumatic output terminal 6 when actuated, thus
functioning as an exhaust valve.
[0049] FIG. 3 shows the detailed construction of the solenoid
valves 7, 8, and 9 in a valve block having appropriate connecting
conduits or channels. The armature 25 of the solenoid valve 7 is of
the same construction as the armature 26 of the solenoid valve 8
and as that of the armature 27 of the solenoid valve 9. It should
be noted that FIG. 3 shows the interconnection of the terminals 11,
13 and 14 of the pneumatic output terminal 6 of the pre-engagement
unit 1 according to the preceding description.
[0050] FIGS. 4a-4f show how different functions can be realized by
using armatures of the same type. The reference numbers are uniform
for the different valve variants, so that they can be transferred
directly from one valve design to another valve design. In FIGS.
4a-4f, a conventional valve design is assumed for simplicity, where
the magnet coil is integrated with the armature. However, the
following functional descriptions can also apply to the valve
cartridge design disclosed below, in which the magnet coil is
located in a component other than the armature unit.
[0051] A normally closed 2/2-way solenoid valve 43 is shown in FIG.
4a in the currentless position of the magnet coil 38. Since no
magnetic force acts in this position, the armature 39 is displaced
by the force of the armature return spring 40 against a valve lift
stop where a sealing seat 31 is provided at this location. An
elastomer insert 41 is pressed against the sealing seat 31 and the
first terminal 35 is hermetically sealed off from the second
terminal 36.
[0052] A normally closed 2/2-way solenoid valve 44 is shown in FIG.
4b in the current flowing state of the magnet coil 38. The armature
39 is pressed by the magnetic force against a valve lift stop 33,
the valve seat 31 opens, and the first terminal 35 is connected to
the second terminal 36.
[0053] The next valve variant shows in FIG. 4c a normally open
2/2-way solenoid valve 45 in the currentless switching state. Under
the action of the armature return spring 40, the armature 39 is
pressed against a valve lift stop 32 which, however, is not
equipped with a sealing seat in this case. In this switching
position, the first terminal 35 is connected to the second terminal
36.
[0054] The normally open 2/2-way solenoid valve 46 is shown in FIG.
4d in the switching state under current. The armature 39 is pressed
against a valve lift stop 34 and due to the shaped surface 42 on
the armature 39 constitutes at this point a metal-to-metal valve
seat together with the second terminal 36. The first terminal 35 is
separated from the second terminal 36. The metal-to-metal valve
seat, contrary to the valve seat described earlier using the
elastomer insert 41, is not hermetically sealing, i.e., leakage
occurs. As explained below, the pneumatic circuit technology used
for the utilization of these valves is selected so that these
leakages are of no importance.
[0055] Although such a valve is not needed with the pre-engagement
unit of the present invention, FIGS. 4e and 4f show for the sake of
completeness that by using the same armature 39, it is also
possible to constitute the 3/2-way solenoid valves 47 and 48.
[0056] In FIG. 4e, the 3/2-way solenoid valve 47 is shown in the
currentless switching state of the magnet coil 38. Under the action
of the armature return spring 40, the armature 39 is pressed
against the valve lift stop 31 with the sealing seat. The first
terminal 35 is separated from the third terminal 37 via this valve
seat, but a connection exists between the first terminal 35 and the
second terminal 36.
[0057] In FIG. 4f, the 3/2-way solenoid valve 48 is shown in its
state under current. The magnetic force causes the armature 39 to
be pressed against the valve lift stop 34 with its shaped surface
42 constituting a metal-to-metal sealing seat. As a result, the
first terminal 35 is separated from the second terminal 36, but the
first terminal 35 is connected to the third terminal 37.
[0058] By comparison with the pneumatic circuit of FIG. 1 which
utilizes the valve design according to FIG. 3, it is shown that in
the rest position of the pre-engagement unit which is given by the
currentless switching state of all three solenoid valves 7, 8 and
9, only hermetically sealing valve seats are being used under the
effect of the armature return spring. Thus, the solenoid valves 7
and 9 are closed and the solenoid valve 8 is open in the
currentless switching state.
[0059] Only when a desired change takes place in the control
chamber pressure in the relay valve 2 is the air admission valve 7
actuated to increase the pressure, or the exhaust valve 9 is
actuated to decrease the pressure, each in pulsating fashion.
[0060] If the influence of the redundancy pressure is to be
eliminated with this pressure increase or pressure reduction, the
redundancy pressure valve 8 is actuated and the redundancy pressure
appearing at the second pneumatic inlet 5 is separated from the
relay valve control chamber (pneumatic output terminal 6) by the
metal-to-metal valve seat which takes effect in this switching
state.
[0061] Since leakage may occur at this valve seat as mentioned
earlier, the separation is not hermetical, i.e., the existing
redundancy pressure will influence the control chamber pressure in
the relay valve 2 to a small extent by the valve seat leakage. This
influence is unimportant, however, since, as explained before, a
pulsating air admission takes place at the same time through the
air admission valve 7, or a pulsating exhaust takes place through
the exhaust valve 9, with the full cross-sections of these valves
taking effect in either case. The leakage cross-section is on the
one hand extraordinarily small as compared to the valve
cross-sections, and on the other hand pulsation is carried out in a
closed regulation loop, i.e., air admission or exhaust pulsation
takes place, until the braking pressure delivered at the pneumatic
output terminal 18 of the relay valve 2 is equal to a target
braking pressure calculated by the electronic control unit. (The
calculation of the target braking pressure value in the electronic
control unit is based, in addition to the electrical braking set
value, on additional influence factors caused by load or ABS brake
regulation.) When the target braking pressure value is reached,
pulsation is terminated and the solenoid valves 7 and 9 are placed
again in the currentless switching state; the redundancy valve 8
continues to remain actuated. If a minute exhaust of the control
chamber of the 2 should now occur due to the metal-to-metal valve
seat, recognized by a lowering of pressure at the pneumatic output
terminal 18, this lowering of pressure is compensated for within
the framework of pressure regulation by means of a single pulsation
of the air admission valve 7.
[0062] When a valve seat is closed by the magnetic force and after
the magnet coil is first subjected to current, only a low magnetic
force flow is built up due to the distance in space between the
armature and the valve seat (the ferromagnetic circuit is not
closed). In order to move the armature at all, a strong current
must produce a strong actuating force which is only a fraction of
the subsequent holding force for the armature. Due to the constant
feeding of a very strong current, the armature of a solenoid valve
is accelerated and thereby kinetic energy is built up which is
dissipated again when the armature touches the valve seat.
[0063] In conventional valves according to the state of the art, an
elastomer insert produces the seal at the valve seat.
[0064] In order to avoid the destruction of the elastomer during a
lasting load by the dissipation of the kinetic accelerating energy
of the armature when it meets the valve seat, such an elastomer
insert is not connected rigidly but elastically to the body of the
armature. In the German patent document DE 27 57 803 A1, FIG. 4
shows an armature with two elastomer sealing inserts (therein 50'
and 52') for two valve seats that are supported elastically
(therein by springs 51 and 53). An elastic sealing seat of this
type of construction requires a relatively long valve stroke that
may be, e.g., 1.2 mm long so that the spring action may be at all
effective. Such a construction also requires a certain minimum
structural size so that an elastic construction may fit in, and
this leads to a relatively large armature mass that in turn
requires a corresponding reinforcement of the armature return
spring. The stronger return spring then leads to an increase of the
required magnetic force to about 30 N with such a valve seat
construction. The switching time (current supplied to the magnet
coil until the valve seat closes) is essentially the time required
to build up the current in the magnet coil and is typically on the
order of 25 ms.
[0065] In applications for pre-engagement, these valves must
normally have a nominal width of approximately 2.2 mm in order to
avoid a sharp pressure drop that may occur through the compressed
air pilot lines which bridge the distance between a valve and the
air accumulating relay valve control chamber.
[0066] When these type of pre-engagement valves are operated in a
closed pressure regulation mode, the nominal value of approximately
2.2 mm causes the emitted pressure not to be very fine-tuned by
steps and the switching time of approximately 25 ms leads with a
conventional scanning regulator to a limitation of the obtainable
pressure gradient of the emitted pressure used.
[0067] With a valve design according to the present invention,
however, and due to the fact that the armature has an elastomer
insert at only one end and not at both ends, and due also to the
fact that on the opposite end of same there is only a shaped
surface to constitute a metal-to-metal sealing seat, it is possible
to employ a small structural form for the armature. As a result,
the mass of the armature is reduced to approximately 6 g and due to
the weak armature return spring, a magnetic force of only
approximately 6 N is required.
[0068] Providing the armature with a shock absorbing coating as
suggested in the German patent document DE 197 30 276 A1 ensures
suitable resistance to acceleration of the shaped surface at the
metal-to-metal sealing seat.
[0069] Due to the fact that the sealing in a metal-to-metal sealing
coat is not achieved by compressing the elastomer and that no range
of spring is necessary, a very short valve stroke of approximately
0.5 mm can be employed. With this short valve stroke and the
already weak armature return spring, an elastic support of the
elastomer insert as in the above-mentioned state of the art is no
longer necessary.
[0070] Thanks to these optimized compressed air connections, the
nominal width of a solenoid valve can be reduced to a value around
1.7 mm, representing an optimal value for a pilot valve in vehicle
applications. It ensures on the one hand that the braking pressure
can be well transmitted in steps, and on the other hand it is not
so small that the usual pollution of the compressed air in vehicles
would play a role.
[0071] By means of the measures described here, the switching times
of the solenoid valves can be reduced to approximately 6 ms instead
of the 25 ms typical of the state of the art. With the reduced
switching times, rapidly changing set target values for the braking
pressure regulator can be realized, and high gradients for the
generated braking pressure can be realized at the output terminal
18 of the relay valve 2.
[0072] FIGS. 5a-5c show the different components associated with a
valve cartridge, in accordance with the invention. In FIGS. 5a and
5b, these components are represented as individual parts before
being assembled. In FIG. 5c, the components are shown in their
assembled state.
[0073] A magnet coil unit 61 (FIG. 5a), a housing 60 (FIG. 5b), and
a valve cartridge 62 (FIG. 5b) are shown as three separate
components. The housing 60 (FIG. 5b), configured with a
square-shaped opening 68, forms a first forked flange 63 and a
second forked flange 64. For manufacturing reasons, the housing 60
can be made up of several parts, as indicated illustratively by the
parting line 67 on the first forked flange 63. In any event, after
assembly of these parts, the housing 60 is considered herein to be
a single component. A first bore 65 is provided in the first forked
flange 63 and, coaxially to the first bore 65, a second pocket bore
66 is provided in the second forked flange 64.
[0074] As shown in FIGS. 5a and 5b, the magnet coil unit 61 and the
square-shaped opening 68 are designed so that the magnet coil unit
61 can be positioned into the square-shaped opening 68 in a first
assembly direction 73. The magnet coil unit 61 has an opening 69 in
the form of a straight circular cylinder. Inside the magnet coil
unit 61 are the actual magnet coil 38 and the sheet metal yoke 70,
which is made of a ferromagnetic material. In order to assemble the
magnet coil unit 61, the magnet coil 38 is inserted into the sheet
metal yoke 70. Then, by using a suitable assembly core to maintain
the 69 opening, these parts are extrusion-coated with a plastic
50.
[0075] The valve cartridge 62 is constructed either in the form of
a straight cylinder with a circular cross-section, or in the form
of a straight stepped cylinder with a circular cross-section. In
the embodiment of FIG. 5b, the valve cartridge 62 is shown in the
form of a stepped cylinder with one cylinder step 71.
[0076] Referring again to FIG. 5b, the larger diameter of the
stepped cylinder valve cartridge 62 (except for the necessary
tolerances) is sized so that it is equal to the diameter of the
first bore 65, and, similarly, the smaller diameter of the stepped
cylinder valve cartridge 62 is sized to be equal to the diameter of
the second pocket bore 66. As such, the valve cartridge 62 can be
inserted into the housing 60 with the magnet coil unit 61 already
in place, in a second assembly direction 74, as indicated in FIG.
5b. Valve cartridge 62 is positioned in the housing 60 so that it
is properly aligned within the magnet coil 61, as will be described
in greater detail below, with respect to FIG. 7.
[0077] Referring now to FIGS. 5b and 5c, the valve cartridge 62 is
then attached to the first forked flange 63 by fastening means 72,
which exerts a force in the assembly direction, i.e., 74. This
force acts via the face of the cylinder step 71 upon the magnet
coil unit 61, and is finally absorbed by the second forked flange
64. The magnet coil unit 61 is thus fixed in place by the effect of
this force. Moreover, this "fixing force" causes the second forked
flange 64 to be elastically spread open relative to the first
forked flange 63.
[0078] Fastening means 72 can be implemented in a variety of ways,
such as caulking, snap ring, threads (positive fit means), or even
such non-positive means as adhesive, or press-connections.
[0079] An alternative method of fixing the axial position of the
magnet coil unit 61 is shown in the embodiment of FIG. 6. In this
embodiment, the valve cartridge 62 has the form of a straight
cylinder with circular cross-section. As such, the diameters of the
first bore 65 and of the second pocket bore 66 are both equal to
the diameter of the straight cylinder valve cartridge 62.
[0080] In similar fashion to the assembly process described above,
the magnet coil unit 61 is positioned in the housing opening 68 of
the housing 60, and the valve cartridge 62 is then inserted in the
assembly direction from forked flange 63 to forked flange 64. Valve
cartridge 62 is then attached by fastening means 72 to the first
forked flange 63, effective on both sides, so that the axial
position of the valve cartridge 62 is fixed within the bores 65 and
66. Illustratively, the enlarged detail of the fastening means 72
shows it in the form of beading.
[0081] The attachment of the valve cartridge 62, however, does not
fix the position of the magnet coil unit 61, which could still be
capable of displacement along the valve cartridge 62 axis.
[0082] As further shown in FIG. 6, the position of the magnet coil
unit 61 is fixed relative to the valve cartridge 62 axis by an
additional component; namely, an electronic board 55. This board 55
is attached by fastening means 56 to the housing 60, so that the
position of the board 55 is fixed relative to the housing 60.
[0083] The magnet coil unit 61 is fixed relative to the electronic
board 55 by contact pins 53, which are inserted into corresponding
receiving sockets 54. These sockets 54 are securely affixed to the
board 55 by means of soldered connections.
[0084] The above described assembly sequence of the FIG. 6
embodiment can also be modified, such that the magnet coil unit 61
is first positioned by introducing its contact pins 53 into the
contacting bores of the board 55, and by soldering to same in a
first phase. Then, the board 55 is connected to the housing 60 by
the fastening means 56, and finally, the valve cartridge 62 is
inserted into the forked flanges 63 and 64, and attached by
fastening means 72 to the first forked flange 63.
[0085] FIG. 7 shows a detailed cross-section view of a valve
cartridge of the type depicted in FIG. 5b, in the form of a 3/2-way
cartridge solenoid valve.
[0086] The valve cartridge in FIG. 7 is configured of three
individual cylindrical bodies, designated as first cylinder body
75, second cylinder body 76, and third cylinder body 77, in the
order of assembly direction. Cylinder bodies 75 and 77 have
circular cross-sections, while cylinder body 76 has a stepped
configuration. Illustratively, cylinder body 76 could have more
than one step, in accordance with design preferences.
[0087] The cylinder bodies 75, 76, and 77 are aligned so that the
cylinder diameter either decreases in the assembly direction (as
shown in FIG. 7), or remains the same. The first cylinder body 75
and the second cylinder body 76 are joined by a connector 78, which
cannot be disconnected by itself. Similarly, the second cylinder
body 76 is joined to the third cylinder body 77 by a connector 79.
In this case, connector 79 could be in the form of a non-separable
connection, such as crimping, pressing, soldering or gluing.
Alternatively, the connector 79 could be in the form of a separable
connection, such as threads.
[0088] The first cylinder body 75 and the second cylinder body 76
are constructed of nonmagnetic material, while the third cylinder
body 77 is made of a ferromagnetic material.
[0089] The second cylinder body 76 is made in the form of a hollow
body, and contains the armature 39 and the armature return spring
40. This configuration is similar to that of references 47 and 48
in FIGS. 4e and 4f.
[0090] At the delimitation of the second cylinder body 76, the
sealing seat 31 (also described above with reference to FIGS. 4a
and 4b) is formed on the first cylinder body 75. Sealing seat 31
also serves as the valve lift stop for the armature 39 when there
is no current flowing in the magnet coil 38.
[0091] A terminal 36 is provided on the third valve body 77, at its
delimitation point with the second valve body 76. Terminal 36
serves as a valve lift stop for the armature 39, when under the
influence of the magnetic force. This constitutes the previously
described metal-to-metal valve seat at the corresponding location
to the interaction with the shaped surface 42 of the armature 39 in
FIGS. 4d and 4f.
[0092] The solenoid valve arrangement in the second cylinder body
76 has the above-mentioned (FIGS. 4e and 4f) first, second and
third terminals 35, 36, and 37, respectively. These terminals are
connected in the indicated sequence by channels in the first (75)
and third (77) cylinder bodies to a first cartridge-pressure medium
terminal 80, a second cartridge-pressure medium terminal 81, and a
third cartridge-pressure medium terminal 82. The type and number of
the cartridge-pressure medium connections are thus determined by
the desired type of solenoid valve. In the illustrative case of
FIG. 7, a 3/2-way solenoid valve is shown, as previously
described.
[0093] The first and third cartridge-pressure medium terminals 80
and 82 provided in the first cylinder body 75 are made in the form
of radial pressure medium terminals. The second cartridge-pressure
medium terminal 81 provided in the third cylinder body 77 is made
in the form of an axial cartridge-pressure medium terminal. The
design of the cartridge-pressure medium terminals 80 and 82 results
from the type of fastening means 72, which covers the front of the
first cylinder body 75. The axial second cartridge-pressure medium
terminal 81 can also be designed as a radial pressure medium
terminal, but can be implemented very simply as an axial
pressure-medium terminal in the form of a simple bore within the
ferromagnetic material.
[0094] Corresponding to the cartridge-pressure medium terminals,
housing-pressure medium terminals for pneumatic interlinking of the
cartridge valves are provided in the housing 60, within the first
and second forked flanges 63 and 64, respectively. In the first
forked flange 63, a first housing-pressure medium terminal 83
connects to the first cartridge-pressure medium terminal 80, while
a third housing-pressure terminal 85 connects to the third
cartridge-pressure medium terminal 82. A second housing-pressure
medium terminal 84 is provided on the second forked flange 64, and
connects to the second cartridge-pressure medium terminal 81.
[0095] Since the first and second cylinder bodies 75 and 76 are
made of a non-ferromagnetic material, they can both be made of a
material such as brass. Furthermore, since they are connected to
each other, the two cylinder bodies can also be made in a single
piece, e.g., as a lathed part. Thus, the inventive objective of
simplifying the manufacturing process leads to the manufacturing of
the two cylinder bodies 75 and 76 as a single part in a single
step.
[0096] When current flows through the magnet coil 38, a strong
magnetic field builds up on the magnetic circuit components of the
valve cartridge 62 and the magnet coil unit 61. The force of this
magnetic field causes the armature 39 to move, since it is part of
the ferromagnetic circuit constituted by the sheet metal yoke 70,
the armature 39, and the third cylinder body 77.
[0097] The sphere of influence of this ferromagnetic circuit
consists of the area designated by reference number 87.
Illustratively, the valve cartridge 62 can be divided into three
functional zones, a first cartridge functional zone 86, a second
cartridge functional zone 87, and a third cartridge functional zone
88.
[0098] The first cartridge functional zone 86 extends from the
beginning of the first cylinder body 75 into the area of the second
cylinder body 76 that is outside the ferromagnetic circuit
described above. The second cartridge functional zone 87 represents
the sphere of influence of the ferromagnetic circuit, and extends
from the beginning of the second cylinder body 76 into the portion
of the third cylinder body 77 where the ferromagnetic circuit ends.
The third cartridge functional zone 88 extends into the third
cylinder body 77 from the end of the ferromagnetic circuit to the
end of the cylinder body.
[0099] The first and third cartridge-pressure medium terminals 80
and 82 are located in the first cartridge functional zone 86, and
the second cartridge-pressure medium terminal 81 is located in the
third cartridge functional zone 88. In addition to defining the
location areas of the pressure medium terminals, the first and the
third cartridge functional zones 86 and 88 also serve for the axial
guidance of the valve cartridge 62.
[0100] The valve cartridges shown in FIGS. 8 and 9 are basically
constructed in the same manner as the valve cartridge of FIG. 7.
Therefore, the descriptions given above for FIG. 7 apply as well to
FIGS. 8 and 9, including the corresponding reference numbers. Since
the valve cartridges of FIGS. 8 and 9 are somewhat simpler in
design than the valve cartridge of FIG. 7, the following
descriptions for FIGS. 8 and 9 are limited to these simplified
differences.
[0101] FIG. 8 shows a valve cartridge 62 with its appertaining
components in the embodiment of a normally closed 2/2-way cartridge
solenoid valve.
[0102] The second cylinder body 76, made in the form of a hollow
body, contains the armature 39 and the armature return spring 40,
similarly to the configurations of reference numbers 43 and 44 in
FIGS. 4a and 4b. As previously described in reference to FIG. 7,
the sealing seat 31 is formed at the delimitation of the second
cylinder body 76, and also serves as a valve lift stop for the
armature 39 when there is no current flowing in magnet coil 38.
[0103] In similar fashion to the valve design described above
(FIGS. 4a and 4b), a first cartridge-pressure medium terminal 80
(FIG. 8) and a housing-pressure medium terminal 83, corresponding
to the first terminal 35 (FIGS. 4a and 4b) are provided. Also,
corresponding to the second terminal 36 (FIGS. 4a and 4b), a second
cartridge-pressure medium terminal 81 and a second housing-pressure
medium terminal 84 are provided. Both cartridge-pressure medium
terminals 80 and 81 are located in the first cartridge functional
zone 86.
[0104] FIG. 9 shows the valve cartridge 62 with its appertaining
components in the embodiment of a normally open 2/2-way cartridge
solenoid valve. The armature 39 and the armature return spring 40
are located in the hollow body of the second cylinder body 76, as
in the description regarding reference numbers 45 and 46 in FIGS.
4c and 4d. The second terminal 36 (FIG. 9), which serves as a valve
lift stop for the armature 39 when subjected to magnetic force, is
located in the third cylinder body 77, at the delimitation to the
second cylinder body 76. Together with the surface 42, as shown in
FIG. 4d, second terminal 36 constitutes a metal-to-metal valve seat
at this location.
[0105] Referring again to FIG. 9, the first cartridge-pressure
medium terminal 80, located in the first cartridge functional zone
86, and the first housing-pressure medium terminal 83 correspond to
the first terminal 35 of FIGS. 4c and 4d Corresponding to the
second terminal 36 of FIGS. 4c and 4d, the second
cartridge-pressure medium terminal 81 (FIG. 9), is located in the
third cartridge functional zone 88, and is connected to the second
housing-pressure medium terminal 84.
[0106] A comparison of FIG. 7 with FIGS. 8 and 9 shows that at
least one cartridge-pressure medium terminal is provided in the
first cartridge functional zone 86, while a pressure medium
terminal may or may not be provided in the third cartridge
functional zone, depending on the type of solenoid valve used.
[0107] Regarding the alternative fixing of the magnet coil unit 61
in FIG. 6, it should be noted that a valve cartridge suitable for
this type of fixing, with three interconnected cylinder bodies, is
basically of identical construction as the valve cartridges shown
in FIGS. 7 to 9. In an embodiment of this type, all the cylinder
bodies are made with a circular cross-section; i.e., there are no
cylinder steps in such valve cartridges.
[0108] As described above, the cylinder steps in a valve cartridge
serve to reduce the diameter in the assembly direction, and can be
in the form of a perpendicular step. However, valve cartridge
cylinder steps may also take a different form, as illustrated in
FIG. 10. In this example, O-rings are used as the sealing means,
capable of being inserted into grooved depressions 95 in the valve
cartridge 62. It may then be advantageous to provide several valve
steps to carry out the diameter reduction, where the valve steps
are either slanted or perpendicular.
[0109] FIG. 10 shows a slanted first valve step 90, a slanted
second valve step 91, a right-angle third valve step 92, and a
slanted fourth valve step 93. This type of design is advantageous,
because the valve cartridge 62 can be inserted with the O-rings
pre-assembled in the grooved depressions 95, without damaging the
O-rings by sliding them over the housing-pressure connections 85
and 83.
[0110] FIG. 10 also shows the fastening means 72 in the form of a
lock ring, so that the valve cartridge 62 has a turned step 94 at
this location. In addition, turned groove connections 96 are made
on the cartridge-pressure medium terminals 80 and 82, which serve
to optimize the flow of air, in the sense that throttled
cross-sections are avoided.
[0111] It should be noted that the turned step 94, the turned
groove connections 96, and the grooved depressions 95 do not
represent cylinder steps as defined in this invention, since the
reductions of diameter which are associated with the turned step
94, the grooved depressions 95 and the turned grooves 96 only
reduce the cylinder diameter temporarily in the assembly
direction.
[0112] FIG. 11 depicts an assembly configuration for a
pre-engagement unit, such as that shown in the schematics of FIGS.
1 and 2. In this configuration, the previously described magnet
coil unit 61 has been incorporated into a compact triple magnet
coil unit 98, which can accommodate three corresponding solenoid
valves. This is achieved through the design of reduced-size
solenoid valves, as explained previously, which can function with
smaller magnet coils.
[0113] Because of the identical internal structure of the three
cartridge solenoid valves, they can be assembled into a compact
triple valve cartridge unit 99.
[0114] It should be noted that a triple valve cartridge unit is
based on a pneumatic circuit that consists in this case of 3
solenoid valves. Moreover, it is essential that a multiple valve
cartridge unit can be designed for all types of pneumatic circuits
that utilize more than one solenoid valve, using the type of
assembly configuration shown in FIG. 11. In like manner, it is also
possible to design a multiple magnet coil unit to fit the multiple
valve cartridge unit.
[0115] The triple valve cartridge unit 99 in FIG. 11 is based on
the circuit of FIG. 2, where the 3/2-way solenoid valve 21 is
designated as the valve cartridge 101 (FIG. 11), the normally open
2/2-way solenoid valve 22 of FIG. 2 is designated as the valve
cartridge 103 (FIG. 11), and the normally closed 2/2-way solenoid
valve 23 of FIG. 2 is designated as the valve cartridge 104 (FIG.
1l). The valve cartridges 101, 103, and 104 are identical with
respect to their mechanical aspects, and are of the type shown in
FIG. 5. As such, the respective cylinder steps 71 shown in FIG. 11
exert a force on the triple magnet coil unit 98 in the direction of
a second assembly direction 74, and thereby fix the unit 98 in its
position.
[0116] In the embodiment shown in FIG. 11, the housing 60 is
modified in such manner that three first bores 65 are provided in
the first forked flange 63, three second pocket bores 66 are
provided in the second forked flange 64, and the block-shaped
opening 68 is enlarged to receive the triple magnet coil unit
98.
[0117] To assemble the pre-engagement unit of FIG. 11, the triple
magnet coil unit 98 is loosely positioned in a first assembly
direction 73 within the block-shaped opening 68 of the housing 60.
Then, the triple valve cartridge unit 99 is inserted into the
housing 60 via the bores 65 in the second assembly direction
74.
[0118] The head element 100 of the triple valve cartridge unit 99
is then connected to the forked flange 63 in a non-positive or
interlocking manner, thereby fixing the triple magnet coil unit 98
within the block-shaped opening 68 of the housing 60. A fixing
means, such as 109 in FIG. 12 (to be described below), is used to
make this connection. The basic positions of the first, second and
third housing-pressure medium terminals 83, 84, 85, respectively,
previously described in FIG. 7, are depicted in FIG. 11 as required
for a 3/2-way solenoid valve cartridge, such as 101. These
housing-pressure medium terminals point in the direction of the
other valve cartridges 103 and 104, so that pneumatic channels can
be formed in the triple valve cartridge unit 99 and in the housing
60, in the same manner as the channels of the solenoid valves 21,
22 and 23, in the pneumatic circuit of FIG. 2. This type of channel
arrangement is basically described in FIG. 3 for the pneumatic
circuit of FIG. 1, and the channels for a circuit according to FIG.
2 can be laid out in the same manner.
[0119] FIG. 12 represents the channel configuration of a 3/2-way
solenoid valve cartridge 101 of the type shown in FIG. 10.
[0120] In FIG. 10, a parting line 102 is shown by broken lines and
delineates the portion of the forked flange 63 of the housing 60
that is uppermost in the drawing. This portion of forked flange 63
can be separated along the parting line 102 to form the head
element 100, as shown in FIG. 12. A head element 100 formed in this
manner (see also FIG. 11), contains the third housing-pressure
medium terminal 85, for the third cartridge-pressure medium
terminal 82.
[0121] FIG. 12 illustrates a section through part of the
pre-engagement unit 1 to show the pressure medium terminals of the
valve cartridge 101 and their associated channels. For simplicity,
the triple magnet coil unit 98 and the 3/2-way solenoid valve
cartridge are not shown cut away in the drawing.
[0122] In addition to the above described change in the forked
flange 63, changes must also be made to the 3/2-way solenoid valve
cartridge 101 in order to form the head element 100. As shown in
FIG. 11, the valve cartridge 101 is connected to the head element
100. In the illustrative embodiment of FIG. 12, this connection is
made by means of a crimping 108. With this interlocking connection,
it is necessary to seal off the pressure chamber formed on the
third cartridge-pressure medium terminal 82 against the atmosphere.
For this purpose, a grooved depression 106, for the pre-assembly of
sealing O-rings, is provided, in addition to the three grooved
depressions 95 shown in FIG. 10. Accordingly, a beveled valve step
105 (FIG. 12) is inserted between the first and the second beveled
valve steps 90 and 91.
[0123] It is advantageous to design the channels for the
connections between the housing-pressure medium terminals of the
solenoid valve cartridges 101, 103, 104 (FIG. 11) in such manner
that the major portion of channel connections is established in
only one separate unit. Since only one terminal, i.e., third
housing-pressure medium terminal 85 (FIG. 12), is provided for the
3/2-way solenoid valve cartridge 101 in the head element 100, it is
advantageous to connect this terminal via the channel guide shown,
and via the sealing O-ring 107, in the event that the head element
100 is attached through the fixing means 109 to the housing 60. As
such, channels exist in the housing 60 for all the
cartridge-pressure medium connections of the valve cartridges 101,
103 and 104 of the pre-engagement unit 1 (FIGS. 11 and 12).
[0124] It should also be noted that the parting line 102 of FIG. 10
could have been displaced in the direction of the magnet coil 38,
so that, e.g., the first housing-pressure medium terminal 83 would
be assigned to the head element 100. With this configuration, the
channel tubings would be more expensive than for the design shown
in FIG. 12, since the first housing-pressure medium terminal 83
would have to be connected via a sealing means to the housing 60.
For this reason, the separation along the parting line 102, as
shown in FIG. 10, represents an optimal solution from the point of
view of simple tubings.
[0125] With reference to FIGS. 10, 11, and 12, channels are formed
within the housing 60, which represent a channel circuit of the
solenoid valve cartridges 101, 103, 104, in accordance with the
pneumatic circuit of FIG. 2. The channel tubings of this pneumatic
circuit are advantageously designed so that the first pneumatic
inlet 4, the second pneumatic inlet 5, and the pneumatic output
terminal 6 of this pre-engagement unit lare brought out at suitable
points of the housing 60 (FIGS. 10-12) for the external
connections.
[0126] Since the pre-engagement unit 1 of FIG. 2 is connected
directly to the relay valve 2, which has a pneumatic connection to
the pressure supply, it is advantageous to bring out the supply
pressure inlet 4 and the pneumatic output terminal 6 at one point,
so that an air transfer to the corresponding pressure channel can
be established. A sealing connection between the relay valve 2 and
the pre-engagement unit 1, whereby the pneumatic terminals 4 and 6
are sealingly connected to the relay valve 2, can, e.g., be
effected in the same manner in which the third housing-pressure
medium terminal 85 is connected to the housing 60 via the O-ring
107 (FIG. 12).
[0127] To complete the pneumatic supply channels of FIG. 2, the
redundancy pressure is connected at the second pneumatic inlet 5 of
the pre-engagement unit 1, in conjunction with the relay valve
2.
[0128] In addition to the previously described pre-engagement unit
of FIG. 11, based on the fixing manner of the valve cartridge in
FIG. 5, it is also possible to build a pre-engagement unit in which
a triple valve cartridge unit is provided, with the individual
valve cartridges designed to correspond to the magnet coil fixing
system of FIG. 6. Since these valve cartridges have the form of a
straight cylinder with a circular cross-section, there is no
necessity in such an embodiment to form a head element that rigidly
combines the different valve cartridges.
[0129] Instead, by utilizing the fixing system of FIG. 6, the three
individual valve cartridges can be held together by, e.g., one
elastic clasp in a loose triple valve cartridge unit. With the
insertion and fixing of the individual valve cartridges in the
manner shown in FIG. 6, the pre-engagement unit is complete.
Finally, the channel tubings to connect the housing-pressure medium
terminals of these valve cartridges can be designed in basically
the same manner as described for FIG. 12.
[0130] While the invention has been described by reference to
specific embodiments, this was for purposes of illustration only.
Numerous alternative embodiments will be apparent to those skilled
in the art and are considered to be within the scope of the
invention.
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