|Title of Invention||
SOLENOID VALVE FOR A LIQUID-CONTROLLED HEATING AND/OR COOLING SYSTEM
|Abstract||The invention proceeds from a solenoid valve (10) for a liquid-controlled heating and/or cooling system,having a valve body (16) with at least one inlet port (12)and at least one outlet port (14),and an electromagnetically switched valve member (18) which makes the connection between the inlet port (12) and the outlet port (14) in a first control position and blocks it in a second control position and also projects with its valve stem (26) through an ar4mature (32) fastened on it into an armature space (42) which is flowed through by liquid at least at times by virtue of the fact that it is connected to conduit sections of the heating and/or cooling system which have a different pressure level.It is proposed that the armature space (42) is connected via movement gaps to a conduit section on the facing side,and via an axial duct (48) in the valve stem (26) to a conduit section on the averted side of the valve member (18)|
Solenoid ■va4ve f or --a—liquid-control 1 pd-Japat i ng
an4/er pooling syctero
The invention proceeds from a solenoid valve for a liquid-controlled heating and/or cooling system having the features of the preamble of Claim 1.
Such solenoid valves are used, in particular, in liquid-controlled heat exchangers for heating and/or cooling systems in motor vehicles. They can be driven under time control as a function of temperature in the heating and/or cooling system or a passenger compartment, the throughflow being determined essentially by the average time cross section. The valve member of the solenoid valve is opened by the liquid pressure and/or a valve spring, and closed by an energised magnet coil of the solenoid valve, by virtue of the f&ct that it acts on an armature connectedl to the valve stem. The space in which the armature is arranged is not hermetically sealed, but filled with liquid. The aim of this is to dampen the movement of the armature hydraulically in order to avoid abrupt closure and pressure surges associated therewith in the liquid system. Furthermore, noises and wear which are produced when the valve member strikes the valve seat wit limit being damped are prevented. However, the
damping action is strongly impaired by gas bubbles, in particular air bubbles, which accumulate in the armature space, for example when the system is being filled. Furthermore, the solenoid valves lean be used as changeover valves which short-circuit th.e coolant flow from an internal combustion engine in the one control
t It is known from DE 195 370 67 CI in the case of a solenoid valve which is arranged in a feed conduit of a heating system heat exchanger to cause a flow through the armature space of the solenoid valve by using the pressure gradient between the feed conduit and the return line, in order to remove the air bubbles from the armature space and to avoid the disadvantages associated therewith. For this purpose, a vent line is provided between the armature space and the return line, while liquid flows from a feed conduit into the vent line via an annular gap between the armature and the coil of the solenoid valve and prevents air bubbles from accumulating in the armature space.
against a stop on the valve stem. If the magnet coil of the solenoid valve is energized, the armature fastened on the valve stem is picked up and the valve stem presses the valve member against a valve seat. If the va1ve member strikes the valve seat without being damped, it causes noises by virtue of the striking impulse and increases wear.
Advantages of the invention
According to the invention, there are provided on the side of the valve stem facing the valve member means which reduce the speed of the valve stem when the valve member closes. These can be elastic elements which are connected between the valve member and the valve stem and decouple the mass of the valve stem with the armature from the mass of the valve member. As a result, the striking impulse of the valve member, and thus the wear as well as the closing noise are strongly reduced.
Springs of suitable design, for example helical springs, leaf springs, cup springs, springs made from rubber, plastic, etc. can be used as elastic elements. They are simple, functionally reliable and are maintenance-free.
element can also be designed to be so strong that in the closed position the valve member is pressed securely against the valve seat by the elastic element. In another variant, the elastic element can be designed such that the closing member is moved into the open per- it ion by the liquid pressure and is pressed against the valve seat only when the magnet coil is energized. A further variant consists in that the elastic element sttarts to act only after a prescribed path of the valve member, and is therefore opened by the liquid flow when the magnet coil is not energized, but is pressed aga i nst the valve seat via the elastic element as soon as the magnet coil is energized.
Tho speed of the valve stem can also be reduced by a damping device which acts on the valve stem or on the valve member. This not only prevents the valve member or the valve stem from continuing to vibrate after mounting of the valve member, but already mounting off the speed of the armature, valve stem and valve member during the valve movement.
Since the means for delaying the valve stem are arranged on the side facing the valve member, it is possible largely to dispense with the damping action in the armature space and with the flow through the latter. When coolant does not flow through the armature space, there is no longer a risk of abraded material and dirt being deposited in the armature space and on thn armature as well as on the electromagnet and impairing both the magnetic and the mechanical properties of the solenoid valve.
separate damping chamber which is sealed with respect, to the outlet port by a diaphragm seal. When the damning disc moves, liquid is displaced from one side of the damping disc to the other via an annular gap. The damping behaviour can be tuned by additional throttling bores in the damping disc.
In order for the mass of the damping disc not substantially to increase the moved masses of the solenoid valve, it is expedient to construct the disc to be thin and to produce it from a light material, for example light metal or plastic. Moreover, these materials have no influence on the magnetic behaviour of the solenoid valve.
In order to ensure that the damping chamber is always
filled with liquid, in accordance with one embodiment
of the invention liquid can be exchanged between the damping chamber and the outlet port via a throttling
Exemplary embodiments of the invention are represented and described in the drawing. Numerous features are represented and described in context in the description and in the claims. The person skilled in the art will also expediently consider the features individually and form them into suitable combinations.
In the drawing:
Fig. 1 shows a cross section to a solenoid valve according to the invention, in a non-pressurised rest position, and
Fig. 2 shows a variant with a damping disc.
Tho solenoid valve 10 is arranged as a rule between an internal combustion engine and a heating system heat exchanger. It has an inlet port 12 which is connected to the internal combustion engine, and an outlet port 14 which is connected to the heating system ;heat exchanger. Provided between the ports 12, 14 is a valve mehiber 18 which cooperates via a valve cone 20 with the valve seat 22 and makes the connection between the inlot port 12 and the outlet port 14 in a first control position and blocks it in a second control position.
The valve member 18 is guided in a valve stem 26 with limited axial displaceability by means of a guide pin
58 (Figure 1) . Fastened on the valve stem 26 is an
armature 32 which cooperates with a magnet coil 28 and is guided in an axially displaceable fashion in an armature space 42 by a guide bushing 40. A stop 38 aqainst which the valve stem 26 bears in the open position of the solenoid valve 10 under the force of a valve spring 24 closes the guide bushing 40 and thus the armature space 42 at the end face. The stop 38 is expediently produced from a damping plastic material.
Tho liquid pressure in the inlet port 12 displaces the valve member 18 into an open position as long as the magnet coil 28 is not energized. When the magnetic coil 28 is energized, a magnet core 30, which is connected to a magnetic return yoke 3 6, picks up the armature 32 against the force of the valve spring 24 and the liquid pressure in the inlet port 12, and the valve member 18 closes the connection between the inlet port 12 and the outlet port 14. Movement gaps for the free movement of the armature 3 2 and the valve stem 2 6 are provided between the armature 32 and the guide bushing 40, as w'll as the valve stem 26 and the magnet core 30.
1. Solenoid valve (10) for a liquid-controlled heating and/or cooling system, having a valve body (16) with at least one inlet port (12) and at least one outlet port (14), and an electromagnetically switched valve member (18) which makes the connection between the inlet port (12) and the outlet port (14) in a first control position and blocks it in a second control position and is connected to a valve stem (26) on which an armature (32) is fastened, characterized in that provided on the side of the valve stem (26) facing the valve member (18) are means for reducing the speed of the valve stem (2 6) when the valve member (18 ) clos.es .
2. Solenoid valve (10) according ;to Claim 1, characterized in that an elastic element (56) is connected between the valve member (18) and the valve stem (26).
3. Solenoid valve (10) according to one of the preceding claims, characterized in that the valve member (18) is guided with limited axial displaceabi 1 ity by means of a guide pin (58) in the valvo stem (26), the elastic element surroundi ng the guide pin (58) and/or the valve stom.
|Indian Patent Application Number||2827/MAS/1998|
|PG Journal Number||26/2007|
|Date of Filing||18-Dec-1998|
|Name of Patentee||ROBERT BOSCH GMBH|
|Applicant Address||PO BOX 30 02 20,D-70442 STUTTGART|
|PCT International Classification Number||B60T08/36|
|PCT International Application Number||N/A|
|PCT International Filing date|