DIRECTIONAL CONTROL VALVE

Abstract: A fluid directional control valve having a valve housing (11) with a valve chamber (15) therein, an elastic seal ring (14) for sealing the valve chamber, valve ports (P1, P2, P3) provided in the housing and connected to the valve cham­ ber, a valve arm (18) having valve bodies (20, 21) and swingably supported in and by the seal ring, and an actuator (23) for actuating the valve arm, so that the valve bodies selectively open and close the valve ports in order to control the fluid connection between the valve ports, in accordance with the swing movement of the valve arm.

Description: The present invention relates to a directional control valve and in particular it relates to a multiway-multiport type of fluid directional control valve. A known two way-three port directional control valve which usually has one open inlet port and two outlet ports, or two inlet ports and one open outlet port to which the inlet ports can be selectively connected, is actuated by a spool or a diaphragm which is, however, rather complex in construction and expensive. In EP-A-160461, there is disclosed a directional control valve comprising first and second valve housings opposed and connected to each other to define a pair of valve chambers therebetween, each chamber having three ports consisting of one permanently open port provided in one of the first and second housings and two opposed selection ports which are provided in the respective first and second housings, a pivotally mounted valve arm which has two parallel legs which extend in the respective valve chambers, said legs having valve bodies for selectively closing and opening said selection ports in response to pivotal movement of the valve arm, a web connecting said valve arms outside the valve chambers and an actuator connected to the said connecting web for pivoting said valve arm. This valve is difficult to seal however and also has a rather complicated construction. The present invention provides a valve of the above type characterised in that the said valve arm is pivotably supported in and by a portion of an elastomeric sealing member which is provided between the first and second housings and around the periphery of the respective valve chambers to seal the chambers, and that the said legs and the said connecting web of said valve arm form an integral and unitary body. With such an arrangement according to the present invention, the construction can be simplified and has no sliding parts, so that the control of the valve ports can be reliably and smoothly carried out. The above features can be used to realize a directional control valve unit which can control multiple valve ports (more than two) at one time by a single common actuator. An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a sectional view of a directional control valve which does not embody the present invention but which is included for purposes of explanation only; Figure 2 is a plan view of a directional control valve which does not embody the invention and has a seal ring and a valve arm, but with a removed valve housing; Figure 3 is a sectional view taken along the line III-III in Figure 2; Figure 4 is a plan view of a directional control valve in accordance with the present invention; Figures 5 and 6 are sectional views taken along the lines V-V and VI-VI in Figure 4; and Figure 7 is a block diagram showing a principle of a directional control valve in two different modes. Fig. 7 shows two operation modes of a fluid directional control valve to which the present invention is directed. In Fig. 7(a), the directional control valve V has one inlet open port P1 and two outlet ports P2 and P3 which are selectively connected to the inlet port P1. On the other hand, in Fig. 7(b), the valve V has two inlet ports P2 and P3 and one outlet port P1 to which the two inlet ports can be selectively connected. In Figs. 1 to 3 which are included for purposes of explanation only and do not show an embodiment of the present invention, a valve has a valve housing 11 consisting of an upper valve housing 12 and a lower valve housing 13. Between the upper and lower valve housings 12 and 13 is provided a valve chamber 15 which is sealed by a seal ring 14 located between the upper and lower housings 12 and 13. The seal ring 14 is made of an elastic material, such as rubber and is preferably convexed at its upper and lower edges to ensure the airtightness thereof, as shown in Figs. 1 and 3. The upper and lower valve housings 12 and 13 are provided with annular concave recesses 12a and 13a complementary to the corresponding convex projections of the elastic seal ring 14, so that the seal ring 14 can be fitted in the concave recesses 12a and 13a, respectively. In the illustrated construction the seal ring 14 is generally an annular rectangle in plan view, as shown in Fig. 2. However, the shape of the seal ring 14 in plan view is not limited to such an annular rectangle, and may be of any closed loop, such as circle or ellipse. The elastic seal ring 14 is compressed by a predetermined amount by the upper and lower valve housings 12 and 13 when the valve housings are firmly connected to each other. The upper valve housing 12 has therein a high pressure valve port (selection port) P2, and the lower valve housing 13 has therein a low pressure port (selection port) P3 which is opposed to the high pressure port P2 of the upper housing 12. The lower valve housing 13 has additionally an open port P1. The three ports P1, P2 and P3 open all into the valve chamber 15. At the connections between the port P2 and the sealed valve chamber 15 and between the port P3 and the sealed valve chamber 15 are provided valve seats 16 and 17, in the ports P2 and P3, respectively. The valve seats 16 and 17 have fluid passages 16a and 17a therein, respectively, to establish a fluid connection between the respective ports P2 and P3 and the sealed valve chamber 15. The valve seats 16 and 17 slightly project into the sealed valve chamber 15. A valve arm 18 is swingably supported in and by the seal ring 14, preferably at the center of the seal ring 14 in the thickness direction, so that the valve arm 18 can swing about the center of seal ring 14. The portion of the valve arm 18 that extends in the sealed valve chamber 15 is sheathed with an cemented outer cover layer 19 made of the same elastic material as the elastic seal ring 14, on the entire surface of the valve arm 18 of that portion. The outer layer 19 can be made as a part of the seal ring 14, during molding of the seal ring 14. Namely, the outer layer 19 and the seal ring 14 can be molded at one time, with the valve arm 18, in an insert molding process. The valve arm 18 has upper and lower valve bodies 20 and 21 at its front or inner end. The valve bodies 20 and 21 can be made by partially raising the outer layer 19 of the valve arm 18 on the upper and lower surfaces of the latter. The valve bodies 20 and 21 are opposed to the corresponding valve seats 16 and 17 of the ports P2 and P3 to selectively open and close the fluid passages 16a (P2) and 17a (P3), respectively. With the molded outer layer 19 of the valve arm 18 integral with the seal ring 14, a highly sealed cementing between the valve arm 18 and the seal ring 14, which serves as a fulcrum of the seesaw movement of the valve arm 18,can be established. Even if a slight gap is produced between the valve arm 18 and the seal ring 14 in which the valve arm is inserted at the connection therebetween, due to a failure of cementing or aging, the gap does not have any adverse influence on the seal effect of the valve chamber 15. The portion of the valve arm 18 that projects outward from the seal ring 14 has a connecting hole 22 in which a plunger 24 of a solenoid actuator 23,which moves the plunger 24 up and down in Fig. 1, is connected. The solenoid actuator 23 which per se is well known has an electromagnetic coil (not shown) which is energized to move (retract) the plunger 24 against a return spring 25. The plunger 24 is moved downward in Fig. 1 by the return spring 25 when the solenoid actuator 23 is deenergized. As can be seen from the foregoing, the valve arm 18 swings in the clockwise direction in Fig. 1, with the help of the return spring 25 when the solenoid actuator 23 is deenergized, so that the upper valve body 20 comes into contact with the upper valve seat 16 to close the valve port P2 and the lower valve body 21 comes away from the lower valve seat 17 to open the port P3. Consequently, the fluid connection is established between the port P3 and the port P1. On the contrary, when the solenoid actuator 23 is energized, the solenoid plunger 24 is retracted against the return spring 25, so that the swing movement of the valve arm 18 in the counterclockwise direction in Fig. 1 takes place. This swing movement of the valve arm in the counterclockwise direction causes the lower valve body 21 to come into contact with the lower valve seat 17 and causes the upper valve body 20 to separate from the upper valve seat 16. Consequently, the fluid connection between the port P3 and the port P1 is broken and the port P1 comes into communication with the port P2. In this way, the ports P2 and P3 can be selectively connected to the port P1 by the solenoid actuator 23. In Fig. 1, the numeral 27 designates a retainer connected to the solenoid plunger 24 to prevent it from separating from the valve arm 18. Figs. 4 to 6 show an embodiment of the present invention, in which a pair of sealed valve chambers 15a and 15b are located side by side in plan view. Each of the valve chambers 15a and 15b has one open port and two selection ports (high pressure port and low pressure port), similarly to the construction illustrated in Figs. 1 to 3. Elements corresponding to those of the construction shown in Figs. 1 to 3 are designated by the same numerals with affixes a and b for the valve chambers 15a and 15b, respectively. One of the most significant features of the embodiment of tie invention shown in Figs. 4 to 6 is a single common valve arm 33. An elastic annular seal ring 31 which is generally rectangular in plan view has a separation rib 32 which defines separate valve chambers 15a and 15b at the middle portion of the rectangle. The sealed valve chamber 15a (15b) has one open port P1a (P1b), high pressure port P2a (P2b), and low pressure port P3a (P3b), connected thereto, similarly to the construction mentioned above. In the embodiment shown in Figs. 4 to 6, the location of the ports P2a and P3a of the valve chamber 15a is opposite to that of the valve chamber 15b. Namely, for the valve chamber 15b, the low pressure port P3b is provided in the upper valve housing 12 and the high pressure port P2b is provided in the lower valve housing 13, contrary to the arrangement of those for the valve chamber 15a, as can be seen from Figs. 5 and 6. The high pressure port P2a is connected to the high pressure port P2b by means of a connecting passage 30 which is formed in the valve housings 12 and 13. The valve arm 33 is generally U-shaped in planview, having a pair of parallel leg portions 33a and 33b, and a web portion 33c connecting the leg portions. The leg portions 33a and 33b are inserted in the seal ring 31 at the center of the seal ring in the thickness direction, so that the leg portions 33a and 33b can swing about the intersections of the leg portions and the seal ring 31. The portions of the leg portions 33a and 33b that project into the sealed valve chambers 15a and 15b are sheathed with outer cover layers 19a and 19b made of the same elastic material as the elastic seal ring 31 and have the valve bodies 20a, 20b and 21a and 21b which can be formed as raised parts of the outer cover layers, similarly to the construction illustrated in Figs. 1 to 3. The web portion 33c of the valve arm 33 has, at its center portion, a connecting hole 22 in which the plunger 24 of the solenoid actuator 23 is inserted and connected. With the arrangement illustrated in Figs. 4 to 6, when the solenoid actuator 23 is deenergized, as shown in Fig. 5, the permanently open port P1a of the sealed valve chamber 15a is connected to the low pressure port P3a, and the open port P1b in the sealed valve chamber 15b is connected to the high pressure port P2b. On the other hand, when the solenoid actuator 23 is energized, the open port P1a in the valve chamber 15a is connected to the high pressure port P2a, and the open port P1b in the valve chamber 15b is connected to the low pressure port P3b. It should be noted here that the arrangement of the three ports P1a (P1b), P2a (P2b), and P3a (P3b) are not limited to the illustrated arrangement, and can be modified, so that, for example the high pressure port P2b is provided in the upper valve housing 12, instead of in the lower valve housing 13 and the low pressure port P3b is provided in the lower valve housing 13, instead of in the upper valve housing 12. In this alternative, the arrangement of the three ports P1a, P2a and P3a for the valve chamber 15a is quite the same as that for the valve chamber 15b. It will thus be seen that the present invention, at least in its preferred forms, provides a simple, reliable and inexpensive directional control valve which uses neither spool nor diaphragm; and furthermore provides a multiway-multiport directional control valve unit which can control a plurality of valve ports at one time by a single actuator.

Claims: 1. A directional control valve (11) comprising first and second valve housings (12, 13) opposed and connected to each other to define a pair of valve chambers (15a, 15b) therebetween, each chamber having three ports consisting of one permanently open port (P1a, P1b) provided in one of the first and second housings (12, 13) and two opposed selection ports (P2a, P3a, P2b, P3b) which are provided in the respective first and second housings (12, 13), a pivotally mounted valve arm (33) which has two parallel legs (33a, 33b) which extend in the respective valve chambers (15a, 15b), said legs (33a, 33b) having valve bodies (20, 21) for selectively closing and opening said selection ports (P2a, P3a, P2b, P3b) in response to pivotal movement of the valve arm (33), a web (33c) connecting said valve arms (33a, 33b) outside the valve chambers (15a, 15b) and an actuator (23) connected to the said connecting web (33c) for pivoting said valve arm (33), characterised in that the said valve arm (33) is pivotably supported in and by a portion of an elastomeric sealing member (31) which is provided between the first and second housings (12, 13) and around the periphery of the respective valve chambers to seal the chambers, and that the said legs (33a, b) and the said connecting web (33c) of said valve arm (33) form an integral and unitary body. 2. A valve as claimed in claim 1 further characterised in that the portions of the said legs (33a, 33b) extending in said chambers (15a, 15b) are sheathed in the same material as the said elastomeric seal member (31). 3. A valve as claimed in claim 2 further characterised in that the valve bodies (20, 21) are formed by partially raising the sheatbing of the said leg portions. 4. A valve as claimed in any preceding claim, further characterised in that the valve bodies (20, 21) are provided at the front ends of the legs (33a, 33b) in the valve chambers (15a, 15b). 5. A valve as claimed in any preceding claim further characterised in that the valve arm (33) is inserted in the seal member (31) at the middle thickness thereof. 6. A valve according to any preceding claim further characterised in that it comprises valve seats with fluid passages in the respective selection ports, so that the valve bodies (20,21) selectively come into contact with the corresponding valve seats, in accordance with the pivotal movement of the valve arm (33). 7. A valve according to any preceding claim further characterised in that selection ports comprise high pressure ports (P2a, P2b) and low pressure ports (P3a, P3b). 8. A valve according to any preceding claim further characterised in that said actuator (23) is a solenoid actuator. 9. A valve according to claim 8, further characterised in that solenoid actuator comprises a solenoid plunger (24) which is connected to the common valve arm (33).

Inventors: AOKI, TOSHIKAZU, ARIIZUMI, RYOZO, EJIRI, TAKASHI, KAINUMA, MASAKUNI, KOJIMA, MASAO, SUDA, SOHJI
Applicants: FUJIKURA RUBBER LTD.
Application year: 1986
Main classification: F16K31
IPC codes: F15C3, F15B13, F16K31