Solenoid coil structure and interconnection

Details Solenoid coil structure and interconnection Solenoid coil structure and interconnection

2000-08-16

2002-03-05

Schwartz, Christopher P. (Department: 3613)

Fluid-pressure and analogous brake systems

Speed-controlled

Having a valve system responsive to a wheel lock signal

C303S119300, C335S255000

Reexamination Certificate

active

06352317

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates in general to anti-lock brake systems and in particular to solenoid valve coil structure and interconnections within a removable anti-lock brake system electronic control module.
An Anti-lock Brake System (ABS) is often included as standard or optional equipment on new vehicles. When actuated, the ABS is operative to control the operation of some or all of the vehicle wheel brakes. A typical ABS includes a plurality of solenoid valves mounted within a control valve body and connected to the vehicle hydraulic brake system. Usually, a separate hydraulic source, such as a motor driven pump, is included in the ABS control valve body for reapplying hydraulic pressure to the controlled wheels during an ABS braking cycle. An ABS further includes an electronic control module which is electrically connected to the pump motor, a plurality of solenoid coils associated with the solenoid valves, and wheel speed sensors for monitoring the speed and deceleration of the controlled wheels. The electronic control module is typically mounted upon the control valve body with the assembled valve body, motor and control module forming a compact unit which is often referred to as an ABS control valve.
During vehicle operation, the ABS control module continuously receives speed signals from the wheel speed sensors. The control module monitors the speed signals for potential wheel lock-up conditions. When the vehicle brakes are applied and the control module senses an impending wheel lock-up condition, the control module is operative to actuate the pump motor and selectively operate the solenoid valves in the control valve to cyclically relieve and reapply hydraulic pressure to the controlled wheel brakes. The hydraulic pressure applied to the controlled brakes is adjusted by the operation of the solenoid valves to limit wheel slippage to a safe level while continuing to produce adequate brake torque to decelerate the vehicle as desired by the driver.
Referring now to
FIG. 1
, there is shown a partial sectional view of a portion of a typical ABS control valve
10
. The control valve
10
includes a plurality of solenoid valves
11
(one shown) mounted in a valve body
12
. Each of the solenoid valves
11
has a valve sleeve
13
which extends upwardly from the top surface of the valve body
12
. Each valve sleeve
13
encloses an axially movable solenoid armature (not shown) which carries a valve ball on one end. As will be explained below, the valve sleeves
13
prevent loss of hydraulic fluid from the control valve
10
during servicing of the electronic control module.
Each valve
11
also includes a solenoid coil
15
. As illustrated in
FIG. 1
, the coil
15
includes a winding
16
comprising a plurality of turns of fine wire wound upon a bobbin
17
. The ends of the winding wire are wound onto a pair of rigid coil leads
18
which extend in an upward direction from the coil
15
. An annular flux ring
20
is disposed between the coil
15
and the valve
11
. A cylindrical flux casing
21
encloses the coil
15
. A pair of lead apertures
22
are formed through the top surface of the casing
21
. The coil leads
18
extend through the casing lead apertures
22
and through a second pair of apertures
23
formed through a Printed Circuit Board (PCB)
24
. The PCB
24
has electrical traces
25
formed upon its top surface. The coil leads
18
are electrically connected to the traces
25
by a solder connection
26
. Electricity is supplied through the electrical traces
25
and coil leads
18
to the coil
15
. The coil
15
generates a magnetic flux field which actuates the solenoid valve
11
. The flux ring
20
and flux casing
21
cooperate to provide a low reluctance return path for the magnetic flux field.
Typically, the PCB
24
carries a microprocessor and other electronic components (not shown) for controlling the ABS. As shown in
FIG. 1
, a removable cover
27
encloses the solenoid coils
15
and the PCB
24
. The PCB
24
is usually attached to the cover
27
to form a compact integrated electronic control module
28
. Because the valve sleeves
13
seal the associated solenoid valves
11
, the electronic control module
28
can be removed from the control valve
10
for servicing the electronic control components without disturbing the vehicle hydraulic brake system.
SUMMARY
This invention relates to an improved solenoid valve coil structure and interconnections within a removable ABS electronic control module.
As described above, the leads of a solenoid valve coil have to be fed through the length of a flux casing and through two apertures formed through the far end of the casing. This requires a rather complex manufacturing operation. It would be desirable to provide a more easily assembled structure for the solenoid valve coil and flux casing assembly. It also would be desirable to reduce the size of the electronic control module to reduce the overall size of the ABS control valve package.
As also described above, to enhance serviceability of ABS electrical components, the leads for the solenoid valve coils are typically soldered to a printed circuit board which is mounted in a removable housing. When the housing is attached to a control valve body, each coil receives a valve sleeve which extends from the valve body and encloses a valve armature. A typical control valve usually includes six to eight solenoid valves. Because of cumulative component tolerances, or tolerance stackup, it is usually necessary to increase the inside diameter of the coils to permit alignment of all the coils with the associated valve sleeves. However, increasing the inside coil diameter can decrease the efficiency of the magnetic circuit. Accordingly, it would be desirable to provide an improved mounting structure for the solenoid valve coils which would accommodate the component tolerances.
The present invention contemplates a solenoid valve coil which includes a winding having at least one lead wire extending therefrom The winding is disposed within a cup shaped flux casing which has an open end with the winding lead wire extending from the open end of the casing. An annular flux ring is disposed within the open end of the flux casing adjacent to the winding. The flux ring having an aperture formed therethrough and the winding lead wire extends through the aperture. Additionally, the lead wire can be formed as a flexible free wire termination, the free wire termination being adapted to be electrically connected to a circuit substrate. The circuit substrate can include a printed circuit board or an overmolded lead frame. The overmolded lead frame cane be formed integrally with a housing.
It is further contemplated that the circuit substrate can be mounted within a housing which is adapted to be attached to an ABS valve body. The circuit substrate being positioned between the valve body and the solenoid coil. The circuit substrate has an aperture formed therethrough which is concentric with the solenoid coil. The circuit substrate aperture receiving a valve sleeve which extends into the solenoid coil. The circuit substrate can have an electronic device mounted thereupon, the electronic device being coupled to the housing whereby the housing forms a heat sink for said electronic device. A thermally conductive adhesive can be disposed between the electronic device and the housing to enhance the conduction of heat from the electronic device to the cover.
The invention also contemplates a solenoid coil having at least one lead wire which is electrically connected to a trace of conductive material formed upon a flexible backing material. The flexible backing material is carried by a housing with the flexible backing material permitting movement of the solenoid relative to the housing. It is further contemplated that the flexible backing material includes a first portion which carries the coil and a second portion mounted upon the housing. The first portion is joined to the second portion by a third portion of the flexible backing material which permits the

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