Patent Application
20100038571
The present invention generally relates to a valve control unit, especially, a pilot control unit for a pressure modulator of a commercial vehicle.
By means of its solenoid valves, a pilot control unit activates an air-flow-boosting relay valve, which, in turn, can activate one or more ducts. For use in an electropneumatic brake system, such as, for example, an electronically regulated brake system (EBS) for trailers, wheel-brake modules having brake cylinders for the wheel brakes are activated by the relay valve.
DE 100 09 116 A1 describes a pilot control unit for a brake pressure modulator in a trailer having an electronic brake system. The solenoid valves are constructed as cartridge solenoid valves, whose valve cartridges are placed in a housing having a solenoid. First, this solenoid is introduced into the housing, and, then, the valve cartridge is inserted in an assembly direction into the housing and joined to the housing. The pilot control unit is provided with a pneumatic and an electrical interface.
DE 10 2004 035 763 A1 describes a valve control device that is preferably provided as a valve control unit for two brake ducts of an electro-pneumatic brake system. It has three valve units, each of which is designed as a valve modulator device for a brake pressure regulating circuit; in this case, an air admission valve is provided with a primary armature and a vent valve is provided with a secondary armature, the two magnet armatures having a common armature guide arrangement and a common solenoid system and being switched at different current intensities. Thus, air can be admitted to the downstream wheel module, the input pressure can be held and venting can be achieved by means of a common solenoid system.
However, such valve control units of pilot control units generally have complex structures and require a large installation space. In particular, the manufacture of a main housing and further components as well as the pneumatic passage of air through diverse air ducts, seals and possibly tubes between the various components is time-consuming and laborious. Mounting of the solenoids and pressure sensors as well as contacting with the electronics via the separate interfaces is also time-consuming and laborious.
In the case of a defect of the sensors, valves or electronics, the entire valve control unit must then be replaced.
It is an object of the present invention to provide a valve control unit, especially, for a pneumatic pressure modulator of a commercial vehicle, that is cost-effective to manufacture, has low susceptibility to malfunction, and can be installed in a small space.
This object is achieved by a valve control unit according to claim 1. The dependent claims describe preferred improvements. The claims additionally describe a pressure modulator with such a valve control unit designed as a pilot control unit.
According to embodiments of the present invention, therefore, the solenoid valves in what is preferably a one-piece housing or housing shell are formed by solenoids housed in the housing and valve cartridges introduced into valve bores, while, furthermore, the pressure sensors are mounted on a side of the housing. Preferably, the pressure sensors (micro-structured) are placed as sensor hybrids or hybrid chip arrangements directly on the top side of the housing. In this case, an electrical interface, in which the solenoids are contacted and the pressure sensors are contacted, is formed on one side of the housing, preferably, the top side of the housing. Thus, the pressure sensors can be directly contacted electrically with a circuit substrate, such as a printed circuit board, and the solenoids can be contacted directly with the circuit substrate.
The inventive valve control unit is space-saving and has low susceptibility to malfunctions, since the internal air supply lines are safe from mechanical damage or leaks. The electrical contacting or bonding via the electrical interface also has low susceptibility to malfunctions. The pressure sensors permit direct measurement of the pneumatic pressures without additional tube connections.
According to the invention, the control device is advantageously not provided directly on the valve control unit but is contacted with the valve control unit via its electrical interface; as an example, however, it may also be mounted directly on the circuit substrate.
Furthermore, the valve control device has a pneumatic interface, which is advantageously formed on one side of the housing as a labyrinth seal or as a contour for a labyrinth seal. This pneumatic interface has ports for a plurality of lines, for example, to a reservoir pressure and for various outputs.
Thus, the valve control housing can be placed with this side directly on the relay valve and pressed against it by means of a screwed connection, for example, without the need for further substantial seals. The pressure chambers of the relay valve can be extended directly, without machining or without substantial machining, to the needed pressure ports of the valve control housing, or in other words to the solenoid valves housed therein or to the pressure sensors.
Advantageously, the valve control housing is constructed and arranged such that the pressure sensors together with the electrical interface are disposed on the top side and the pneumatic interface is disposed on the opposite side, or in other words the bottom side, and the solenoid valves are oriented in horizontal direction relative thereto. Thus, air supply bores run from the pneumatic interface to the top side, just underneath the pressure sensors, and further to the bores that house the valve cartridges of the solenoid valves. These bores can be formed directly in the plastic housing, without substantial finish-machining.
As an example, the solenoids can be introduced from the top side, for which purpose there is formed a recess such as a molded pocket beginning at the top side of the valve control housing. According to one variant, therefore, the circuit substrate can be introduced from above together with already soldered solenoids or can be placed on the solenoids and contacted therewith or soldered thereto; thereafter, the circuit substrate forms the electrical interface or contains an additional plug as the electrical interface. The pressure sensors or sensor hybrids, which are also placed from above, can be contacted directly with the circuit substrate, for example by being bonded thereto. The valve internals are preferably designed as valve cartridges and can be introduced in sideways direction into the solenoids; thus, manufacture and assembly can be achieved very easily in a few process steps. The valve cartridges can be used for fixing and, if necessary, also for retaining the solenoids.
The valve control housing can be manufactured relatively simply, for example as an injection-molded part having molded pockets and completely formed bores or ducts, and can be equipped in a few process steps with the further components, or, in other words, the circuit substrate with solenoids soldered thereto, valve cartridges and pressure sensors or sensor hybrids. Thereafter, the valve control unit can be placed directly on the relay valve and pressed sealingly against it, for example, by screwed connections.
The inventive valve control unit can be used as a pilot control unit both in an electro-pneumatic brake system, or, in other words, in an electro-pneumatic brake pressure modulator for activation of the relay valves for the downstream brake ducts, and in an electro-pneumatic level-regulating system with air bellows for level regulation or traction regulation.
An exemplary embodiment of the invention will be explained in greater detail hereinafter on the basis of the attached drawings, wherein:
A pilot control unit 1 is provided with a pilot control housing 2, preferably made of plastic, in which there are housed solenoid valves 4, 5, 6. Bores 3, into which valve cartridges 4a, 5a, 6a are introduced, run in transverse direction through pilot control housing 2. In the interior of pilot control housing 2 there is provided a free space, formed as a molded pocket 9, for solenoids 16, into which valve cartridges 4a, 5a, 6a are introduced. A circuit substrate 7, for example, a printed circuit board 7 having an electrical interface 8, such as, for example, a plug 8, is mounted on top side 2a of pilot control housing 2. Solenoids 16 are fastened directly to printed circuit board 7 at contacts M1+, M1−, M2+, M2−, M3+, M3−. According to
On top side 2a there are further mounted pressure sensors 10, for example in the form of micro-structured chip sensors (DIE sensors) having a sensor chip on a chip substrate, such as a ceramic hybrid. On bottom side 2b of pilot control housing 2 there is formed a pneumatic interface 14 of pilot control unit 1, from which interface air ducts 12 run to pressure sensors 10 and to solenoid valves 4, 5, 6. Pneumatic interface 14 is simply pressed against relay valve 18 to form a sealing labyrinth; for this purpose, seals 31 are provided at pneumatic interface 14.
Pressure sensors 10 can be fastened directly, that is, without chip substrate, to top side 2a of pilot control housing 2 and contacted with printed circuit board 7 by bond connections.
Depending on the application, different valves can be used as the solenoid valves, for example a 3/2-way valve as redundancy valve 5, which, in its de-energized condition, (redundancy case) permits pneumatic gating control of the brake-force transducer of the driver, and, in its energized condition, permits electro-pneumatic EBS control.
Furthermore, in a simple case, there can be provided a 2/2-way valve as air admission valve 4 and a further 2/2-way valve as vent valve 6. According to a preferred embodiment, two-stage solenoid valves 4 and 6 of the type known in principle from DE 10 2004 035 763 A1 are provided for this purpose. Thus, each solenoid valve 4, 6, respectively, has a 2/2-way primary valve on its primary side and a 3/2-way valve on its secondary side, the primary armature and secondary armature being guided in a common armature guide tube and controlled by a common solenoid system having two current levels. In the de-energized condition, the primary valve is then open and the secondary valve is in its air admission position, thus, permitting admission of air or supply of control pressure. At a first, lower current intensity, the primary valve closes without change of the secondary valve, so that the pressure is held in the downstream pneumatic cylinder; at the second, higher current intensity, the secondary valve is displaced (while the primary valve remains shut off without change) such that venting can take place via the secondary valve.
Valves 4, 5, 6 are in communication with pneumatic interface 14 via air ducts 12 formed internally in pilot control housing 2.
Advantageously, therefore, no electrical control device is provided on this pilot control unit 1. Control is exercised via electrical interface 8.
Alternatively, however, printed circuit board 7 can also be equipped with the control device, such as a microprocessor and/or further electronic components of a regulator.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2006 044 764.6 | Sep 2006 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2007/007761 | 9/6/2007 | WO | 00 | 3/13/2009 |
