Poppet valve

Abstract

[Problem] To surely mount a packing on a valve rod so that the packing does not fall off from the valve rod during operation of the selector valve in a poppet valve. [Solution] In a state where one lateral surface 26d of a ring-shaped packing 26 is brought into contact with a packing mounting surface 27 formed in a packing mounting part 17 of a valve rod 11, and an inner circumferential part 26a of the packing 26 is fitted into a packing support groove 29 formed at the inner diameter end of the packing mounting surface 27, an outer circumferential part 26b of the packing 26 is held between the packing mounting surface 27 and a packing pressing member 30 attached to the packing mounting part 17, whereby the packing 26 is brought into contact with the packing mounting surface 27.

Description

Poppet valve

[0001] The present invention relates to a poppet valve that opens and closes a flow path by moving a seal member (packing) attached to a valve rod into and out of contact with a valve seat portion formed in a valve housing so as to surround the opening of the flow path.

[0002] As examples of this type of poppet valve, Patent Document 1 discloses one in which the sealing member of the valve stem (valve rod) is formed from a rubber lining (see FIG. 1) and one in which the sealing member is formed from a packing (see FIG. 4).

[0003] Among these, poppet valves in which the seal member is formed from a rubber lining require lining work to form the seal member on the valve rod and finishing work after the lining work, resulting in the problem of labor-intensive and expensive manufacturing. In contrast, poppet valves in which the seal member is formed from a packing have the advantage of being easy and inexpensive to manufacture because they do not require lining work or finishing work after the lining work on the valve rod. However, when the seal member is formed from a packing as in the latter case, as shown in Figure 4 of Patent Document 1, when the packing is attached to the valve rod, a packing attachment groove is formed in the valve rod and only the inner periphery of the ring-shaped packing is fitted into this packing attachment groove. This means that there is a risk that the packing will fall out of the packing attachment groove when the poppet valve is operated.

[0004] In order to reliably prevent the packing from falling off, it is preferable to form a packing mounting groove 62 in the valve rod 60 that can accommodate both the inner and outer peripheries of the packing 61, as shown in FIG. 12, for example. However, it is difficult to form such a packing mounting groove 62 in the valve rod 60 by cutting, and even if it were possible to form such a packing mounting groove 62, it would also be difficult to mount the ring-shaped packing 61 therein.

[0005] Japanese Patent Application Laid-Open No. 2006-46414

[0006] The technical object of the present invention is to reliably mount a poppet valve having a seal member made of a packing on a valve rod so that the packing does not fall off the valve rod when the poppet valve is operating.

[0007] In order to achieve the above object, the present invention provides a poppet valve having a valve housing having a flow passage therein, and a valve rod accommodated in the valve housing so as to be freely displaceable, and a ring-shaped packing attached to the valve rod is moved toward and away from a ring-shaped valve seat formed in the valve housing so as to surround an opening of the flow passage, thereby opening and closing the flow passage. The poppet valve is characterized in that the valve rod has a cylindrical packing attachment portion, and an annular packing attachment surface surrounding the central axis of the valve rod is formed on an end face of the packing attachment portion facing the valve seat portion, and the packing has inner and outer circumferential portions, a first side face that moves toward and away from the valve seat portion, and a second side face on the opposite side, and is attached to the packing attachment surface by fitting the inner circumferential portion into a packing support groove formed on an inner diameter end of the packing attachment surface with the second side face abutting the packing attachment surface, and by holding the outer circumferential portion between a packing retainer member attached to the packing attachment portion and the packing attachment surface.

[0008] In the present invention, it is preferable that the packing gland member has a main body portion for attachment to the packing attachment portion and an annular locking portion bent inward from a cylindrical tip portion of the main body portion, the tip portion covering the outer periphery of the packing, the locking portion abutting the first side surface of the packing at a position close to the outer periphery, thereby holding the outer periphery of the packing between the tip portion and the locking portion and the packing attachment surface. In this case, the locking portion of the packing gland member may have a plurality of notches formed in the radial direction.

[0009] Furthermore, in the present invention, it is preferable that the packing support groove is formed between an annular groove forming portion formed on the valve rod and the packing mounting surface, the outer diameter of the groove forming portion is smaller than the outer diameter of the packing mounting portion, the outer peripheral end of the groove forming portion faces the inner peripheral end of the locking portion of the packing retainer member, and an annular space portion is formed between the outer peripheral end of the groove forming portion and the inner peripheral end of the locking portion, into which the valve seat portion is interposed when the packing approaches or separates from the valve seat portion.

[0010] In the present invention, a recessed step portion for attaching the main body portion of the packing gland member is formed on the outer periphery of the packing mounting portion, and by making the step of the recessed step portion equal to the thickness of the main body portion, the outer periphery of the packing mounting portion and the outer periphery of the main body portion of the packing gland member can be positioned on the same cylindrical surface.

[0011] According to the present invention, the inner peripheral portion of the packing is fitted into the packing support groove, and the outer peripheral portion of the packing is attached to the packing attachment surface of the valve rod with the packing retainer member and the packing attachment surface held between them. This allows the packing to be firmly and reliably attached to the valve rod so that it will not fall off when the switching valve is operating.

[0012] FIG. 1 is a perspective view showing an embodiment of a poppet valve according to the present invention. FIG. 2 is a cross-sectional view of a main portion of the poppet valve of FIG. 1, showing only the valve portion. FIG. 3 is an enlarged view of a main portion of FIG. 2. FIG. 3 is an enlarged view of a main portion of FIG. 3. FIG. 5 is a perspective view of a valve rod. FIG. 5 is an exploded view of FIG. 5. FIG. 6 is a plan view of a packing. FIG. 7 is a cross-sectional view taken along line VIII-VIII of FIG. 7. FIG. 8 is a plan view of a packing gland member. FIG. 9 is a cross-sectional view of a valve portion showing an operating state different from that of FIG. 3. FIG. 10 is a cross-sectional view of a main portion showing a preferred installation example of a poppet valve.

[0013] 1 and 2 show an electromagnetically operated three-port valve as an example of a poppet valve 1 according to the present invention. This poppet valve 1 has a valve section 2 and an electromagnetically operated section 4 connected to the upper end of the valve section 2 via a connecting block 3.

[0014] The valve unit 2 has a square block-shaped valve housing 5, with a first port 6 and a third port 8 opened on one side (front side) of the valve housing 5 and a second port 7 opened on the other side (rear side) of the valve housing 5. In this embodiment, the first port 6 functions as an input port when connected to a pressure fluid source such as air, the second port 7 functions as an output port when connected to a fluid pressure device such as an air cylinder, and the third port 8 functions as an exhaust port when opened to the outside.

[0015] As is clear from FIG. 3 , the valve housing 5 has a valve hole 10 formed therein that extends from a first end (upper end) 5 a on the electromagnetic operating unit 4 side to near a second end (lower end) 5 b on the opposite side, and the first port 6, second port 7, and third port 8 communicate with the valve hole 10 through communication openings 6 a, 7 a, and 8 a at different positions along the central axis L, and a valve rod 11 is inserted into the valve hole 10 so as to be freely displaceable along the central axis L of the valve hole 10.

[0016] A portion of the upper end of the valve hole 10, i.e., the portion communicating with the first port 6, is formed inside a sleeve 12 made of metal or synthetic resin, which is airtightly attached to the inside of the valve housing 5 via an O-ring 13. An annular flow path 14 communicating with the communication port 6a is formed in the sleeve 12 so as to surround the sleeve 12, and a plurality of connecting holes 14a connecting the annular flow path 14 and the valve hole 10 are formed in the radial direction.

[0017] The valve rod 11 is made of a metal such as stainless steel or iron, and as can be seen from FIGS. 3 to 6 , has a first land 15 at one end (upper end) that seals the upper end of the valve hole 10, a second land 16 at the other end (lower end) that seals the lower end of the valve hole 10, and a central packing attachment portion 17 located within a valve chamber 18 formed in the center of the valve hole 10 in the direction of the central axis L, and sealing O-rings 19 are attached to the first land 15 and the second land 16, respectively.

[0018] The first port 6 and the third port 8 communicate with the valve chamber 18 at opposing upper and lower positions in the direction of the central axis L through flow paths 21, 22 that form part of the valve hole 10 and their openings 21 a, 22 a, and the second port 7 communicates with the valve chamber 18 at an intermediate position between the upper and lower openings 21 a, 22 a through the communication port 7 a.

[0019] Furthermore, the valve housing 5 is formed with ring-shaped first and second valve seat portions 24 and 25 at the portion where the openings 21 a and 22 a communicate with the valve chamber 18, so as to surround the openings 21 a and 22 a. Of these, the first valve seat portion 24 is formed on the sleeve 12 so as to surround the opening 21 a of the flow path 21 leading to the first port 6, and the second valve seat portion 25 is formed on a portion of the valve housing 5 so as to surround the opening 22 a of the flow path 22 leading to the third port 8. In this case, the sleeve 12 is attached to the valve housing 5, and therefore can be considered to be a part of the valve housing 5. Therefore, the first valve seat portion 24 formed on the sleeve 12 can be considered to be formed on a part of the valve housing 5.

[0020] The packing mounting portion 17 of the valve rod 11 is cylindrical, and flat packing mounting surfaces 27 for mounting a ring-shaped packing 26 forming a sealing member are formed on one end face of the packing mounting portion 17 facing the first valve seat portion 24 at one end (upper end) in the direction of the central axis L, and on the other end face thereof facing the second valve seat portion 25 at the other end (lower end) in the direction of the central axis L. The packing 26 is mounted on each of the packing mounting surfaces 27, 27 by fitting an inner peripheral portion 26a of the packing 26 into a packing support groove 29 formed on the inner diameter end of the packing mounting surface 27, and by holding an outer peripheral portion 26b of the packing 26 in a packing hold-down member 30 attached to the outer periphery of the packing mounting portion 17. The cylindrical shape of the packing mounting portion 17 may be a cylindrical shape having a constant diameter as a whole, as shown in FIGS. 3 and 4, or may be a cylindrical shape like a beer barrel with a slightly bulging central portion.

[0021] The packing 26 is formed in a ring shape from an elastic material such as synthetic rubber, and as shown in Figures 7 and 8, has the inner peripheral portion 26a, the outer peripheral portion 26b, a flat first side surface 26c that comes into contact with and separates from the valve seat portions 24, 25, and a flat second side surface 26d that comes into close contact with the packing mounting surface 27.

[0022] 4, 9 and 10, the packing gland member 30 is a separate member from the valve rod 11, and is formed by pressing a stainless steel plate, for example. As is clear from FIGS. 4, 9 and 10, the packing gland member 30 has a cylindrical main body 31 for attachment to the packing attachment portion 17, and a ring-shaped locking portion 32 bent inward from the tip of the main body 31. The main body 31 has a base end 31a and a tip end 31b continuing to the locking portion 32. The base end 31a is fitted onto and fixed to the outer periphery of the packing attachment portion 17. The tip end 31b covers the outer periphery 26b of the packing 26. The locking portion 32 abuts against a first side surface 26c of the packing 26 at a position close to the outer periphery 26b. As a result, the outer periphery 26b of the packing 26 is held between the tip end 31b and locking portion 32 of the packing gland member 30 and the packing attachment surface 27.

[0023] In this way, by fitting the packing 26 onto the packing mounting surfaces 27, 27 with its inner peripheral portion 26a fitted into the packing support groove 29 and its outer peripheral portion 26b embraced by the packing retainer member 30, the packing 26 can be firmly and reliably mounted on the valve rod 11 so that it will not fall off from the packing mounting surfaces 27, 27 when the switching valve is operating.

[0024] A groove 28 for venting air can be formed on the outer periphery of the packing 26, and this groove 28 makes it possible to prevent air from being trapped in the embraced portion, i.e., between the tip end 31b and engagement portion 32 of the packing hold-down member 30 and the outer periphery 26b of the packing 26 and the packing attachment surface 27, when the outer periphery 26b of the packing 26 is embraced between the packing hold-down member 30 and the packing attachment surface 27.

[0025] 9 and 10, the locking portion 32 of the packing gland member 30 can be formed with a plurality of notches 33 radially recessed in the radial direction of the locking portion 32, and these notches 33 can increase the flow path area and increase the air flow rate when the packing 26 separates from the valve seats 24, 25. As shown in Fig. 9, the depth of the notches 33 is a depth d that does not reach from the inner diameter end 32a to the outer diameter end 32b of the locking portion 32, but as shown for one notch 33a in Fig. 9, the depth can also be formed to a depth D that reaches from the inner diameter end 32a to the outer diameter end 32b of the locking portion 32.

[0026] As shown in FIG. 4, a recessed step 35 is formed on the outer periphery of the packing mounting portion 17 at a portion where the base end 31 a of the main body 31 of the packing gland member 30 is fitted, and the step of this recessed step 35 is made equal to the thickness of the main body 31, so that the outer periphery of the packing mounting portion 17 and the outer periphery of the main body 31 of the packing gland member 30 are positioned on the same cylindrical surface, preventing the formation of a step between the two outer peripheries. As a result, when the poppet valve 1 operates, turbulence caused by the step is prevented from occurring when air flows along the outer periphery of the packing mounting portion 17.

[0027] The packing gland member 30 can be fixed to the packing mounting portion 17 by spot welding, caulking, adhesive, screwing, or other methods depending on the materials of the packing gland member 30 and the packing mounting portion 17. The base end portion 31a of the main body 31 of the packing gland member 30 does not necessarily have to be cylindrical, and can have any shape that can be fixed to the packing mounting portion 17.

[0028] Furthermore, the packing support groove 29 is formed between an annular groove forming portion 36 formed in the packing mounting portion 17 and the packing mounting surface 27. The outer diameter of the groove forming portion 36 is smaller than the outer diameter of the packing mounting portion 17, and the outer peripheral end of the groove forming portion 36 faces the inner peripheral end of the locking portion 32 of the packing gland member 30. A ring-shaped space 37 is formed between the outer peripheral end of the groove forming portion 36 and the inner peripheral end of the locking portion 32, and the valve seat portions 24, 25 are interposed between the groove forming portion 36 and the inner peripheral end of the locking portion 32 when the packing 26 approaches or moves away from the valve seat portions 24, 25.

[0029] A rod return spring 39 is interposed at the lower end of the valve hole 10 between a hole end wall 38 closing the lower end and the lower end surface of the valve rod 11, and the valve rod 11 is constantly urged upward by the rod return spring 39. The valve rod 11 is formed with a central hole 40 that passes through the interior of the valve rod 11 in the direction of the central axis L, and a communication hole 41 that connects the central hole 40 with the flow path 22 that leads to the third port 8.

[0030] At the upper end of the valve hole 10, a displacement member 42 is housed inside the sleeve 12 so as to be displaceable in the direction of the central axis L, and the lower surface of the displacement member 42 abuts the upper end surface of the valve rod 11. The displacement member 42 is shaped like a short cylinder and has a central hole 43 that passes through the displacement member 42 in the direction of the central axis L and a plurality of engagement holes 44 that extend in a direction perpendicular to the central hole 43. The lower end of a transmission shaft 45 is inserted into the central hole 43 so as to be displaceable in the direction of the central axis L, and an engagement pin 46 attached to the transmission shaft 45 is inserted into the engagement hole 44. A head 45a that also serves as a spring seat is formed at the upper end of the transmission shaft 45, and a coil-shaped iron core return spring 47 is interposed between the lower surface of the head 45a and the upper surface of the displacement member 42.

[0031] The electromagnetic operating unit 4 has an operating unit housing 50, and is connected to the upper end of the valve unit 2 via the connecting block 3 by screwing the lower end of a connecting shaft 51 protruding from the underside of the operating unit housing 50, which has a male thread on its outer periphery, into a connecting hole 52 of the connecting block 3, which has a female thread on its inner periphery.

[0032] A solenoid mechanism (not shown) that converts electrical energy into mechanical energy is housed inside the operation unit housing 50. This solenoid mechanism has an electromagnetic coil and a fixed core that generate a magnetic field when current is applied, a movable core that is attracted to the fixed core and displaced downward by the generation of the magnetic field, and a push rod 53 that displaces together with the movable core, the push rod 53 being displaceably housed in a rod accommodating hole 54 that extends inside the connecting shaft 51 along the central axis L, the lower end of the push rod 53 being located in a large diameter portion 54a at the lower end of the rod accommodating hole 54 and abutting against a head 45a at the upper end of the transmission shaft 45 that fits into the large diameter portion 54a.

[0033] An electrical connection portion 55 is provided on the operating portion housing 50, and a lead wire 57 is connected to the electrical connection portion 55 via a connector 56, so that power is supplied to the electromagnetic coil through the lead wire 57. Note that a known solenoid mechanism can be applied to the present invention as is, and therefore detailed illustrations and explanations thereof are omitted.

[0034] In the poppet valve 1 having the above-described configuration, Figures 2, 3 and 4 show the case where the electromagnetic operating unit 4 is off (de-energized). At this time, the movable iron core in the solenoid mechanism is not attracted to the fixed iron core, so the push rod 53 is not pushed down by the movable iron core, but is pushed up via the transmission shaft 45 by the urging force of the iron core return spring 47, and occupies the raised position shown in the figure together with the transmission shaft 45. Furthermore, as the transmission shaft 45 rises, the engagement pin 46 engages with the upper end wall of the engagement hole 44 of the displacement member 42, and the displacement member 42 also occupies the raised position integrally with the transmission shaft 45. Therefore, the valve rod 11 is pushed up by the rod return spring 39 to occupy the first position shown in the figure, and the upper packing 26 in the packing mounting portion 17 abuts against the first valve seat portion 24 to close the opening 21 a of the flow path 21, while the lower packing 26 moves away from the second valve seat portion 25 to open the opening 22 a of the flow path 22. As a result, the flow path connecting the first port 6 and the second port 7 is blocked, and the flow path connecting the second port 7 and the third port 8 is opened.

[0035] From this state, when the electromagnetic operating unit 4 is turned on (energized state), the movable iron core of the solenoid mechanism is attracted to the fixed iron core and descends, which pushes down the push rod 53, so that, as shown in Figure 11, the transmission shaft 45 is pushed down by the push rod 53, the iron core return spring 47 is compressed, and the displacement member 42 is pushed down by its biasing force, and the valve rod 11 is pushed down by the displacement member 42 and displaced to the second position shown in the figure. As a result, the upper packing 26 of the packing mounting portion 17 moves away from the first valve seat 24 to open the opening 21a of the flow path 21, and the lower packing 26 abuts against the second valve seat 25 to close the opening 22a of the flow path 22. As a result, the flow path connecting the first port 6 and the second port 7 is connected, and the flow path connecting the second port 7 and the third port 8 is blocked.

[0036] In the above embodiment, an electromagnetically operated three-port valve is shown as the poppet valve 1, but the poppet valve 1 according to the present invention may be a valve of an operation type other than an electromagnetically operated type, for example, a mechanically operated type, a manually operated type, or a pilot operated type, or may be a valve other than a three-port valve, for example, a two-port valve.

[0037] REFERENCE SIGNS LIST 1 Poppet valve 5 Valve housing 11 Valve rod 17 Packing mounting portion 21, 22 Flow path 21a, 22a Opening 24, 25 Valve seat portion 26 Packing 26a Inner peripheral portion 26b Outer peripheral portion 26c First side surface 26d Second side surface 27 Packing mounting surface 29 Packing support groove 30 Packing retainer member 31 Main body portion 31a Base end portion 31b Tip portion 32 Locking portion 33 Notch 35 Recessed step portion 36 Groove forming portion 37 Space portion

Claims

1. A poppet valve having a valve housing having an internal flow passage, and a valve rod accommodated within the valve housing so as to be freely displaceable, and opening and closing the flow passage by moving a ring-shaped packing attached to the valve rod into and out of contact with a ring-shaped valve seat formed in the valve housing to surround an opening of the flow passage, wherein: the valve rod has a cylindrical packing attachment portion, and an annular packing attachment surface surrounding the central axis of the valve rod is formed on an end face of the packing attachment portion facing the valve seat portion, and the packing has inner and outer periphery portions, a first side face that comes into and out of contact with the valve seat portion and a second side face on the opposite side, and with the second side face abutting against the packing attachment surface, the inner periphery portion is fitted into a packing support groove formed on the inner diameter end of the packing attachment surface, and the outer periphery is held between a packing retainer member attached to the packing attachment portion and the packing attachment surface, thereby being attached to the packing attachment surface.

2. The poppet valve described in claim 1, characterized in that the packing retaining member has a main body for attachment to the packing mounting portion and an annular locking portion bent inwardly from the cylindrical tip of the main body, the tip covering the outer periphery of the packing and the locking portion abutting the first side of the packing at a position close to the outer periphery, thereby embracing the outer periphery of the packing between the tip and locking portion and the packing mounting surface.

3. The poppet valve according to claim 2, wherein the engaging portion of the packing gland member is formed with a plurality of notches in the radial direction.

4. A poppet valve as described in claim 2 or 3, characterized in that the packing support groove is formed between an annular groove forming portion formed on the valve rod and the packing mounting surface, the outer diameter of the groove forming portion is smaller than the outer diameter of the packing mounting portion, the outer peripheral end of the groove forming portion faces the inner peripheral end of the locking portion of the packing retainer member, and an annular space is formed between the outer peripheral end of the groove forming portion and the inner peripheral end of the locking portion, into which the valve seat portion is interposed when the packing approaches and separates from the valve seat portion.

5. A poppet valve as described in any one of claims 1 to 3, characterized in that a recessed step for mounting the main body of the packing retainer member is formed on the outer periphery of the packing mounting portion, and the step of the recessed step is made equal to the thickness of the main body, so that the outer periphery of the packing mounting portion and the outer periphery of the main body of the packing retainer member are positioned on the same cylindrical surface.

6. A poppet valve as described in claim 4, characterized in that a recessed step for mounting the main body of the packing retainer member is formed on the outer periphery of the packing mounting portion, and the step of the recessed step is made equal to the thickness of the main body, so that the outer periphery of the packing mounting portion and the outer periphery of the main body of the packing retainer member are positioned on the same cylindrical surface.

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