ELECTROMAGNETICALLY ACTUATABLE EXPANSION VALVE

Abstract

The invention relates to an electromagnetically actuatable expansion valve for a refrigerant, said valve comprising a valve body (1) with a bore (2), in which a substantially cylindrical valve slide (3) is arranged such that it can be displaced axially in order to connect a supply line (4) to a discharge line (5). According to the invention, the discharge line (5) is formed by a hollow cylinder (6) which is inserted in the bore (2) and the end of which facing the valve slide (3) forms a valve seat (7) that can be closed by means of a separate valve closure element (8).

Claims

1. An electromagnetically actuatable expansion valve for a refrigerant, the expansion valve comprising a valve body (1) with a bore (2), in which an essentially sleeve-like valve slide (3) is accommodated in an axially displaceable manner in order to connect an inlet (4) to an outlet (5), wherein the outlet (5) is formed by a hollow cylinder (6) which is inserted into the bore (2), wherein an end of the hollow cylinder, which is directed toward the valve slide (3), forms a valve seat (7), and wherein the expansion valve also comprises a separate valve-closing element (8) movable to engage the valve seat (7) to close the outlet (5).

2. The expansion valve as claimed in claim 1, characterized in that the hollow cylinder (6) has a collar region (9), which extends radially outward and allows a force-fitting, form-fitting and/or integral connection between the hollow cylinder (6) and the valve body (1).

3. The expansion valve as claimed in claim 1, characterized in that the valve-closing element (8) is configured to be displaced axially via the valve slide (3).

4. The expansion valve as claimed in claim 1, characterized in that the valve-closing element (8) is accommodated in the valve slide (3).

5. The expansion valve as claimed in claim 1, characterized in that the valve-closing element (8) is spherical, wherein the spherical valve closing element (8) is surrounded by a cage (10), which is forced by a force of a spring (11) in a direction of a base surface (12) of the valve slide (3).

6. The expansion valve as claimed in claim 5, characterized in that the force of the spring (11) opposes a magnetic force of an electromagnet (13), which serves for actuating the expansion valve, wherein the electromagnet (13) interacts with a displaceable armature (14) and an armature bolt (15), which is connected to the armature (14).

7. The expansion valve as claimed in claim 6, characterized in that, for mechanical coupling to the slide valve (3), the armature bolt (15) is guided through a central opening (16) of the valve body (1).

8. The expansion valve as claimed in claim 1, characterized in that the essentially sleeve-like valve slide (3) has at least one lateral-surface through-passage (17) which, in order to connect the inlet (4) to the outlet (5), is configured to coincide with an annular groove (19) and/or radial bore (18) formed in the valve body (1).

9. The expansion valve as claimed in claim 1, characterized in that the expansion valve is normally open.

10. The expansion valve as claimed in claim 1, characterized in that the outlet (5) can only be closed via the valve-closing element (8) when, at the same time, the connection between the inlet (4) and the outlet (5) has been interrupted by the valve slide (3).

11. The expansion valve as claimed in claim 1, characterized in that the valve-closing element (8) is spherical.

12. The expansion valve as claimed in claim 5, characterized in that the force of the spring (11) opposes a magnetic force of an electromagnet (13), which serves for actuating the expansion valve.

13. The expansion valve as claimed in claim 5, characterized in that the expansion valve is normally open, wherein the force of the spring (11) keeps the expansion valve open.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0019] A preferred embodiment of the invention will be explained in more detail hereinbelow with reference to the accompanying drawing.

[0020] The FIGURE shows a schematic longitudinal section through a preferred embodiment of an expansion valve according to the invention.

DETAILED DESCRIPTION OF THE DRAWING

[0021] The expansion valve illustrated schematically in the FIGURE comprises a valve body 1 with a bore 2, in which a valve slide 3 is accommodated in an axially displaceable manner. The valve slide 3 is of essentially sleeve-like design and has lateral-surface through-passages 17, which can be made to coincide with an annular groove 19, into which open out radial bores 18 which serve as an inlet 4. Accordingly, in dependence on the axial position of the through-passages 17 of the valve slide 3 in relation to the annular groove 19 of the valve body 1, it is possible to free a flow cross section which determines the throughflow and can be altered via axial displacement of the valve slide 3.

[0022] In order also to realize a shut-off function, the expansion valve additionally has a spherical valve-closing element 8, which interacts with a valve seat 7. The expansion valve illustrated is thus designed in the form of a slide/seat valve. This means that it combines the functions of a slide valve and a seat valve. The valve seat 7 is formed on a hollow cylinder 6, which is inserted into the valve body 1 and is connected to the latter in a force-fitting manner via a collar region 9. The hollow cylinder 6 serves, at the same time, as an outlet 5. On account of the distance by which the hollow cylinder extends axially into the valve body 1, the valve seat 7 ends up located approximately centrally in relation to the axial extent of the bore 2. In the present case, the valve seat 7 is located level with the center axis of the radial bores 18 serving as the inlet 4. The spherical valve-closing element 8 is kept in abutment against the valve slide 3 by a cage 10. For this purpose, the cage 10 is prestressed axially in relation to a base surface 12 of the valve slide 3 by means of the force of a spring 11. The spring 11 serves, at the same time, as a valve spring, of which the force keeps the expansion valve open in its de-energized state.

[0023] By virtue of the valve-closing element 8 being arranged within the valve slide 3, said valve-closing element ends up located outside the flow path of the coolant. This optimizes flow through the expansion valve.

[0024] It is also the case that both the advantages of a slide valve and the advantages of a seat valve, these advantages consisting, in particular, in that the slide valve allows precise regulation of the throughflow and the seat valve allows complete shut-off, come to the fore.

[0025] The slide/seat valve design, however, requires just one actuating means. In the present case, this is formed by an electromagnet 13. The electromagnet 13 comprises an annular coil 20, which surrounds certain regions of a displaceable armature 14. The armature 14 is connected to an armature bolt 15, which serves to transmit the displacement of the armature 14 to the valve slide 3. For this purpose, the armature bolt 15 is guided through an opening 16 of the valve body 1, and therefore it butts against the end side of the valve slide 3. If the coil 20 of the electromagnet 13 is energized, this results in the formation of a magnetic field, of which the magnetic force pulls the armature 14 downward. The armature 14 here carries along the armature bolt 15, which, in turn, causes the valve slide 3 to be adjusted axially. The region over which the lateral-surface through-passages 17 of the valve slide 3 coincide with the annular groove 19 of the valve body 1 alters here, and therefore the throughflow is reduced. If the annular groove 19 is covered over completely, the connection between the inlet 4 and the outlet 5 is interrupted by the valve slide 3. However, the valve slide 3 does not fully seal the annular gap remaining between it and the valve body 1, and therefore refrigerant can continue to penetrate into the valve by way of leakage. In this phase, then, use is made of the seat valve, since, as advancement of the valve slide 3 continues, the latter pushes the spherical valve-closing element 8 into the valve seat 7. The high level of sealing of the seat valve ensures that the refrigerant no longer passes outward via the outlet 5.