JP7418807B2 - valve device - Google Patents

Description

The present invention relates to a valve device used in, for example, a car air conditioner.

A pressure regulating valve is disclosed in Patent Document 1 as an example of a conventional valve device. The pressure regulating valve of Patent Document 1 includes a cylindrical main body case, a valve body, and a bellows. The main body case has a fluid flow path. A valve body and a bellows are disposed within the fluid flow path. A guide, a stem, a bellows holding portion, and a coil spring are arranged within the bellows. The guide is formed into a cylindrical shape. The stem has one end fixed to the bellows retainer and is supported so as to be movable in the axial direction relative to the guide. Both ends of the coil spring are in contact with the guide and the bellows presser, and bias the guide and the bellows presser in a direction that separates them. The guide and stem are placed inside the coil spring.

The bottom plate of the bellows is connected to the valve body through a connection plate, and the bottom plate of the bellows, the connection plate, and the valve body are attached toward the valve seat located on the inlet side of the fluid flow path. to strengthen

Patent No. 6149755

In the pressure regulating valve of Patent Document 1, when the fluid pressure on the inlet side of the main body case increases, the valve body moves to the outlet side. The movement of the valve body toward the outlet side pushes the bottom plate portion of the bellows and the connecting plate toward the outlet side, thereby compressing the coil spring. At this time, the coil spring may buckle in the radial direction, causing the coil spring to rub against the bellows or the guide. Therefore, there was a possibility that the opening characteristic of the valve body depending on the fluid pressure would be affected.

In order to suppress the buckling of the coil spring, it is possible to use a coil spring with a large spring constant to suppress the aspect ratio, but if a single coil spring with a large spring constant is used, the buckling of the valve may increase or decrease due to the amount of opening and closing of the valve. The problem is that the change in spring load becomes large, causing the evaporation temperature to rise when the valve is opened wide or under high load, and the evaporation temperature to become low and the evaporator to freeze when the valve opening is to be narrowed at low loads. there were.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a valve device that can suppress buckling of a coil spring while maintaining appropriate valve opening characteristics.

In order to achieve the above object, a valve device according to the present invention includes a main body case having a fluid flow path, a valve body disposed within the fluid flow path and moving in the fluid flow direction, and a valve body disposed within the fluid flow path that moves in the fluid flow direction. a bellows arranged in the valve body, the upstream end of which is connected to the valve body, and the downstream end of which is fixed to the main body case; A plurality of coil springs are arranged.

In the present invention, it is preferable that the valve device further includes a ring member disposed between the plurality of coil springs.

According to the present invention, the valve device includes a plurality of coil springs arranged in series within the bellows so as to expand and contract in response to expansion and contraction of the bellows. By doing so, the aspect ratio of each of the plurality of coil springs can be made smaller compared to a configuration having only one coil spring. Therefore, deformation of each coil spring in the radial direction can be suppressed.

1 is a sectional view of a pressure regulating valve according to an embodiment of a valve device of the present invention. FIG. 3 is a cross-sectional view schematically showing a stem, a guide, a spring receiving member, and a coil spring in a valve closed state.

Hereinafter, a pressure regulating valve according to an embodiment of the valve device of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a sectional view of a pressure regulating valve according to an embodiment of the valve device of the present invention. FIG. 2 is a cross-sectional view schematically showing the stem, guide, spring receiving member, and coil spring in the valve closed state. FIG. 2(a) shows the pressure regulating valve of the present example, and FIG. 2(b) shows the pressure regulating valve of the comparative example.

The pressure regulating valve of this embodiment is placed between an evaporator and a compressor in, for example, a car air conditioner. This pressure regulating valve prevents frost formation on the evaporator by adjusting the pressure of the refrigerant (fluid) in the evaporator so that it does not fall below a predetermined pressure.

As shown in FIG. 1, the pressure regulating valve 1 includes a main body case 10, a valve body 20, and a bellows assembly 30.

The main body case 10 has a case main body part 11, a case outlet part 16, and a washer 17.

The case main body portion 11 is formed into a substantially cylindrical shape. The case main body portion 11 integrally has an inlet end portion 12, an intermediate portion 13, and an outlet end portion 14 that are coaxially connected in the direction of the axis L. The inlet end 12 is provided with an inlet channel 12a having a circular cross-sectional shape. The intermediate portion 13 is provided with an intermediate flow path 13a having a larger diameter than the inlet flow path 12a. The outlet end 14 has a larger inner diameter than the intermediate flow path 13a. An annular valve seat 15 is provided in a stepped portion 11 a between the inlet side end portion 12 and the intermediate portion 13 of the case body portion 11 . The valve seat 15 is oriented towards the outlet side (i.e. the downstream side, the left side in FIG. 1).

The case outlet portion 16 is formed into a substantially cylindrical shape. The case outlet portion 16 is provided with an outlet flow path 16a. The inlet flow path 12a, the intermediate flow path 13a, and the outlet flow path 16a are coaxially connected and constitute the fluid flow path 5. The direction of the axis L is also the flow direction of the refrigerant flowing through the fluid flow path 5. The case outlet section 16 has an end on the inlet side (that is, the upstream side, the right side in FIG. 1) inserted into the outlet side end 14 of the case main body 11. A groove-shaped annular recess is formed on the outer periphery of the case outlet portion 16. An O-ring is placed in the annular recess. The O-ring is sandwiched between the case body 11 and the case outlet 16 and elastically deforms to ensure airtightness of the fluid flow path. The case outlet part 16 is fixed to the outlet side end part 14 by caulking, with a washer 17 sandwiched between the case outlet part 16 and the case main body part 11 .

The washer 17 integrally includes a circular annular portion 18 and a plurality of legs 19. A female thread 18a is formed on the inner peripheral surface of the circular annular portion 18. The plurality of leg portions 19 are arranged on the outer peripheral surface of the circular annular portion 18 at intervals in the circumferential direction. In this embodiment, three leg portions 19 are arranged at equal intervals in the circumferential direction. A plurality of legs 19 extend radially from the circular annular portion 18 . The washer 17 has the tips of the plurality of legs 19 sandwiched between the case main body 11 (specifically, the step between the intermediate section 13 and the outlet end 14) and the case outlet 16. There is.

The valve body 20 integrally includes a small diameter portion 21 and a large diameter portion 22. The small diameter portion 21 is formed in a cylindrical shape. The outer diameter of the small diameter portion 21 is slightly smaller than the inner diameter of the inlet channel 12a. The small diameter portion 21 is slidably inserted into the inlet channel 12a. The small diameter portion 21 is arranged coaxially with the inlet channel 12a on the axis L. The small diameter portion 21 is provided with a slit-shaped communication hole 21a extending in the circumferential direction. The large diameter portion 22 is formed into a disk shape with a larger diameter than the small diameter portion 21 . The large diameter portion 22 is coaxially connected to the small diameter portion 21 and is arranged in the intermediate flow path 13a. The valve body 20 is arranged so as to span the inlet channel 12a and the intermediate channel 13a. The valve body 20 is movable in the direction of the axis L.

The valve body 20 opens and closes the fluid flow path 5. Specifically, when the valve body 20 moves toward the inlet side, the large diameter portion 22 comes into contact with the valve seat 15, and the intermediate flow path 13a is closed with respect to the inlet flow path 12a (valve closed state). When the valve body 20 moves toward the outlet side, the large diameter portion 22 separates from the valve seat 15, and the intermediate flow path 13a is opened to the inlet flow path 12a (valve open state). In the valve open state, the inlet flow path 12a is connected to the intermediate flow path 13a via the inner flow path 21b of the valve body 20 and the communication hole 21a.

The bellows assembly 30 includes a bellows 31, an adjusting screw member 32, a guide 36, a stem 37, a spring receiving member 38, coil springs 39A, 39B, a ring member 39C, and a connecting plate 40. There is. The guide 36, stem 37, spring receiving member 38, coil springs 39A, 39B, and ring member 39C are arranged within the bellows 31.

The bellows 31 integrally includes a peripheral wall portion 31a and a bottom plate portion 31b. The peripheral wall portion 31a is formed into a tubular shape having an expandable and contractible bellows structure. A bottom plate portion 31b is connected to the peripheral wall portion 31a so as to close the upstream end of the peripheral wall portion 31a. An adjustment screw member 32 is attached to the peripheral wall 31a so as to close the downstream end of the peripheral wall 31a. The internal space of the bellows 31 is sealed. The inside of the bellows 31 is kept in a vacuum state. Alternatively, the inside of the bellows 31 is filled with an inert gas such as nitrogen or helium. The bellows 31 is arranged downstream of the valve body 20 in the intermediate flow path 13a. The bottom plate portion 31b, which is the upstream end of the bellows 31, is connected to the valve body 20 via a connecting plate 40. The downstream end of the bellows 31 is fixed to the washer 17 of the main body case 10 via an adjustment screw member 32.

The adjustment screw member 32 integrally includes a threaded portion 33 and a lid portion 34. The threaded portion 33 is formed into a substantially cylindrical shape. The threaded portion 33 has a male thread 33a formed on its outer peripheral surface. The male thread 33a is screwed into the female thread 18a of the washer 17. A nut 41 is screwed onto the male thread 33a. The lid portion 34 is formed into a substantially disk shape. The lid portion 34 is coaxially connected to the threaded portion 33. The peripheral edge of the lid 34 is fixed to the downstream end of the peripheral wall 31a of the bellows 31 by welding. A circular guide receiving recess 35 is provided at the center of the surface of the lid 34 facing upstream.

The guide 36 integrally includes a guide main body portion 36a, a bottom wall portion 36b, and a flange portion 36c. The guide main body portion 36a is formed in a cylindrical shape. The bottom wall portion 36b closes the upstream end of the guide body portion 36a. A through hole 36d is provided in the bottom wall portion 36b. The flange portion 36c is an annular protrusion that protrudes radially outward at the downstream end of the guide main body portion 36a. The flange portion 36c is arranged within the guide receiving recess 35.

The stem 37 is formed into a cylindrical shape. The stem 37 integrally includes a body portion 37a and a shaft portion 37b. The body portion 37a is slidably accommodated in the guide body portion 36a of the guide 36. The shaft portion 37b has a smaller diameter than the body portion 37a, and is inserted into the through hole 36d of the guide 36. The stem 37 is supported by the guide 36 so as to be movable in the axial direction. The guide 36 and the stem 37 are arranged within the bellows 31 so that their respective axes coincide with the axis L. The guide 36 and the stem 37 are configured to move relative to each other in the direction of the axis L as the bellows 31 expands and contracts.

The spring receiving member 38 is formed into a circular dish shape. The spring receiving member 38 is fixed to the tip of the shaft portion 37b of the stem 37 by caulking. The spring receiving member 38 is in contact with the bottom plate portion 31b of the bellows 31.

The coil springs 39A and 39B are compression coil springs. The coil springs 39A and 39B have the same configuration (material, wire diameter, coil inner diameter, coil outer diameter, number of turns, length, etc.). Coil springs 39A, 39B may have different configurations. The ring member 39C is made of metal or resin, and is formed into an annular plate shape.

The coil springs 39A and 39B are arranged in series in the direction of the axis L with the ring member 39C interposed therebetween. The outer diameter of the ring member 39C is larger than the outer diameter of the coil springs 39A and 39B. The inner diameter of the ring member 39C is larger than the outer diameter of the guide main body portion 36a of the guide 36 and smaller than the inner diameter of the coil springs 39A and 39B. The inner diameters of the coil springs 39A and 39B are smaller than the outer diameter of the flange portion 36c of the guide 36 and smaller than the outer diameter of the spring receiving member 38.

A guide 36 and a stem 37 are arranged inside the coil springs 39A, 39B and the ring member 39C. The coil springs 39A, 39B and the ring member 39C are arranged between the flange portion 36c of the guide 36 and the spring receiving member 38. The coil springs 39A and 39B push the bottom plate portion 31b of the bellows 31 upstream via the spring receiving member 38. Therefore, the spring receiving member 38 is pressed against the bottom plate portion 31b of the bellows 31 by the coil springs 39A and 39B. Thereby, the stem 37 fixed to the spring receiving member 38 is interlocked with the bottom plate portion 31b. The force of the coil springs 39A, 39B pushing the bottom plate portion 31b of the bellows 31 is supported by the guide 36 and the adjustment screw member 32.

Although the pressure regulating valve 1 of this embodiment has two coil springs 39A and 39B, it may have three or more coil springs. In the pressure regulating valve 1, the ring member 39C may be omitted and the coil springs 39A and 39B may be directly arranged in series. In the pressure regulating valve 1, the two coil springs 39A, 39B and the ring member 39C are not fixed to each other, but may be fixed to each other by welding, adhesion, or the like.

The connection plate 40 is formed into a disk shape. The connection plate 40 is fixed to the bottom plate portion 31b of the bellows 31 by welding. The connection plate 40 is arranged coaxially with the bottom plate portion 31b. The connection plate 40 is held by the large diameter portion 22 of the valve body 20 so as to be movable in the radial direction (direction perpendicular to the axis L). The bellows 31 and the valve body 20 are connected by the connection plate 40.

Next, the operation of the pressure regulating valve 1 described above will be explained.

In the pressure regulating valve 1, the bellows 31 and the coil springs 39A and 39B push the valve body 20 upstream (referred to as "force F1") by the force (referred to as "force F1") that pushes the valve element 20 downstream. When the force F2'' is large, the valve body 20 contacts the valve seat 15 and the valve is closed.

In the valve closed state, when the pressure of the refrigerant in the inlet channel 12a becomes high and the force F1 becomes larger than the force F2, the valve body 20 moves downstream and separates from the valve seat 15 to open the valve. state. In the valve open state, the spring receiving member 38 connected to the valve body 20 via the connection plate 40 and the bottom plate portion 31b of the bellows 31 moves downstream together with the valve body 20. At this time, the coil springs 39A and 39B are compressed together with the bellows 31.

In the valve open state, when the pressure of the refrigerant in the inlet flow path 12a becomes low and the force F1 becomes smaller than the force F2, the valve body 20 moves upstream, and the valve body 20 contacts the valve seat 15 to close the valve. state. At this time, the coil springs 39A and 39B expand together with the bellows 31. That is, the coil springs 39A and 39B are arranged within the bellows 31 so as to expand and contract in accordance with the expansion and contraction of the bellows 31.

FIG. 2 schematically shows the guide 36, stem 37, spring receiving member 38, and coil spring inside the bellows 31 in the valve open state. FIG. 2(a) is a cross-sectional view schematically showing a configuration (this embodiment) having two coil springs 39A and 39B. FIG. 2(b) is a cross-sectional view schematically showing a configuration (comparative example) having one coil spring 139 instead of the two coil springs 39A and 39B.

As shown in FIG. 2(a), in the configuration having two coil springs 39A, 39B, the aspect ratio (free length/coil average diameter) of each of the coil springs 39A, 39B becomes small. Therefore, when the coil springs 39A, 39B are compressed, it is possible to prevent the coil springs 39A, 39B from deforming in a radial direction.

On the other hand, in the configuration having one coil spring 139 as shown in FIG. 2(b), the aspect ratio of the coil spring 139 becomes large. Therefore, when the coil spring 139 is compressed, there is a risk that the coil spring 139 will be deformed so as to bend in the radial direction.

Furthermore, when the coil springs 39A and 39B having a spring constant a are combined in series to achieve the same spring constant k as one coil spring 139, the following formula (1) holds true (however, the thickness of the ring member 39C is (assumed to be negligible). Then, equation (2) is derived from equation (1).
1/k=(1/a)+(1/a)... (1)
a=2k... (2)

As is clear from equation (2), the spring constant a of each of the coil springs 39A and 39B is set to twice the spring constant k. Therefore, compared to one coil spring 139, the wire diameter of the coil springs 39A and 39B can be made larger. Thereby, the rigidity of the coil springs 39A and 39B can be increased, and radial deformation can be suppressed more effectively. Moreover, when the rigidity of the coil springs 39A, 39B is high, the parallelism of both ends of the coil springs 39A, 39B can be easily increased when polishing the ends.

As described above, the pressure regulating valve 1 of this embodiment has two coil springs 39A and 39B arranged in series within the bellows 31 so as to expand and contract in accordance with the expansion and contraction of the bellows 31. By doing this, the aspect ratio of each of the coil springs 39A and 39B can be made smaller than in a configuration having only one coil spring. Therefore, deformation of the coil springs 39A, 39B in the radial direction can be suppressed.

Moreover, the pressure regulating valve 1 has a ring member 39C arranged between the coil springs 39A and 39B. Therefore, compared to a configuration in which the ring member 39C is omitted and the coil springs 39A, 39B are directly arranged in series, the wire rods of the coil springs 39A, 39B can be brought into contact with a relatively wide surface. Thereby, the ends of the coil springs 39A and 39B can be stably supported. Further, by changing the thickness (size in the direction of axis L) of the ring member 39C, the force with which the coil springs 39A and 39B press the valve body 20 can be adjusted.

Although the embodiments of the present invention have been described above, the present invention is not limited to these examples. Additions, deletions, and design changes to the above-mentioned embodiments by those skilled in the art as appropriate, as well as combinations of features of the embodiments as appropriate, are also within the scope of the present invention, as long as they do not go against the spirit of the present invention. included in the range.

DESCRIPTION OF SYMBOLS 1... Pressure adjustment valve, 5... Fluid channel, 10... Main body case, 11... Case main body part, 11a... Step part, 12... Inlet side end, 12a... Inlet channel, 13... Intermediate part, 13a... Intermediate flow Channel, 14... Outlet side end, 15... Valve seat, 16... Case outlet, 16a... Outlet channel, 17... Washer, 18... Circular annular part, 18a... Female thread, 19... Leg, 20... Valve body, DESCRIPTION OF SYMBOLS 21... Small diameter part, 21a... Communication hole, 21b... Inner flow path, 22... Large diameter part, 30... Bellows assembly, 31... Bellows, 31a... Peripheral wall part, 31b... Bottom plate part, 32... Adjustment screw member, 33... Screw Part, 33a...Male thread, 34...Lid, 35...Guide receiving recess, 36...Guide, 36a...Guide main body, 36b...Bottom wall, 36c...Flange, 36d...Through hole, 37...Stem, 37a...Body Part, 37b...Shaft part, 38...Spring receiving member, 39A, 39B...Coil spring, 39C...Ring member, 40...Connection plate, 41...Nut, L...Axis line

Claims (2)

a main body case having a fluid flow path;
a valve body disposed within the fluid flow path and moving in the fluid flow direction;
a bellows arranged in the fluid flow path, having an upstream end connected to the valve body and a downstream end fixed to the main body case;
A valve device comprising: a plurality of coil springs arranged in series within the bellows so as to expand and contract in accordance with expansion and contraction of the bellows. The valve device according to claim 1, further comprising a ring member disposed between the plurality of coil springs.

Images