JP6960343B2 - Gas flow control valve - Google Patents

Description

The present invention relates to a gas flow control valve that is used in a gas appliance that burns fuel gas and controls the gas flow rate of the fuel gas.

In gas appliances that burn fuel gas, it may be necessary to finely control the gas flow rate in a small gas flow rate range. For example, in a gas stove, it is necessary to finely control the heating power with a toro fire in order to prevent burning during cooking. For this reason, gas appliances such as gas stoves employ a needle-type gas flow rate control valve that can finely control the flow rate in a small gas flow rate range as a control valve for controlling the gas flow rate of fuel gas.

The needle-type gas flow rate control valve includes an elongated cylindrical valve shaft, a tapered flow rate control unit formed on the tip side of the valve shaft, and a valve hole into which the tip side of the flow rate control unit is inserted. .. Then, when the valve shaft is moved forward and backward in the axial direction, the area of the gap formed between the elongated flow control unit and the valve hole changes to enable fine flow control. It has become. Further, the cylindrical valve shaft is held in a state where it can move forward and backward in the axial direction by the valve bearing, and the gap between the outer peripheral surface of the valve shaft and the inner peripheral surface of the valve bearing is made of rubber. It is kept airtight by the ring.

When the valve shaft is moved forward and backward in the axial direction, the O-ring fitted in the valve shaft slides with respect to the inner peripheral surface of the valve bearing. Alternatively, when the O-ring is fitted on the valve bearing side, the O-ring slides with respect to the outer peripheral surface of the valve shaft. Therefore, in order to prevent wear and seizure of the O-ring due to this sliding, the O-ring is assembled in a state where grease is applied (for example, Patent Document 1).

JP-A-2007-032873

However, with the needle-type gas flow control valve described above, it becomes difficult to control the gas flow rate of the fuel gas when the gas appliance is used for a long period of time, and the fine gas flow rate is particularly small in a small gas flow rate range. There was a problem that it could be difficult to control. Therefore, as a result of investigating the cause in detail, when the valve shaft is repeatedly moved forward and backward to control the gas flow rate, the grease applied to the O-ring moves to the flow rate control unit formed at the tip of the valve shaft. It was found that this was because the gap between the flow control unit and the valve hole was narrowed. As a result of further investigation, a mechanism that can move to the flow control unit where the grease should not reach has been clarified.

The present invention has been made based on the newly obtained findings described above, and finely controls the gas flow rate of the fuel gas in a small flow rate range even when the gas appliance is used for a long period of time. It is an object of the present invention to provide a gas flow rate control valve capable of the above.

In order to solve the above-mentioned problems, the gas flow rate control valve of the present invention adopts the following configuration. That is,
In a gas flow control valve that is used for a gas appliance that burns fuel gas and controls the gas flow rate of the fuel gas.
A valve shaft formed in a cylindrical shape and
A flow control unit formed in a tapered shape on the tip side of the valve shaft,
A valve hole into which the tip side of the flow control unit is inserted,
A valve bearing that holds the valve shaft in a state where it can move forward and backward in the axial direction by inserting the valve shaft, and
An O-ring coated with grease while keeping airtightness between the outer peripheral surface of the valve shaft and the inner peripheral surface of the valve bearing,
It is provided with a drive unit that reduces the gas flow rate of the fuel gas by advancing the valve shaft and increases the gas flow rate of the fuel gas by retreating the valve shaft.
In the valve shaft, the shaft diameter of the valve shaft is stepped at a position between the pull-in portion, which is a portion drawn into the valve bearing by moving the valve shaft forward and backward, and the flow rate control portion. A diameter-expanding wall is formed to expand the diameter .
The enlarged diameter wall is a side wall surface of the obstacle groove formed on the outer peripheral surface of the valve shaft on the flow rate control unit side, even when the valve shaft is retracted to a position where the fuel gas reaches the maximum flow rate. , The valve bearing is formed at a position outside the valve bearing .

In the gas flow control valve according the present invention, when Ru to advance the valve shaft while inserting the flow control unit of the tapered shape formed on the distal end side of the valve shaft in the valve hole, the flow rate control unit and the valve hole gas flow rate decreases by Tsu is small size of the formed gap between. On the contrary, when the valve shaft is retracted, the gas flow rate increases due to the increase in the gap formed between the flow rate control unit and the valve hole. The valve shaft is supported by the valve bearing and can move forward and backward in the axial direction, and the outer peripheral surface of the valve shaft and the inner peripheral surface of the valve bearing are kept airtight by the O-ring, and the O-ring Grease is applied. In addition, a part of the outer peripheral surface of the valve shaft is a pull-in portion that is pulled into the valve bearing by moving the valve shaft forward and backward, and the valve shaft is located between the pull-in portion and the flow rate control unit. A diameter-expanding wall is formed in which the shaft diameter of the bearing is increased in a stepwise manner. The diameter-expanded wall is a side wall surface of the obstacle groove formed on the outer peripheral surface of the valve shaft on the flow rate control unit side, and even when the valve shaft is retracted to a position where the fuel gas reaches the maximum flow rate, the valve is valved. It is formed at a position outside the bearing.

As described above, since it is only the retracted portion that may be drawn into the valve bearing as the valve shaft moves forward and backward, the grease applied to the O-ring adjusts the flow rate formed on the tip side of the valve shaft. It is hard to think of moving to a part. In the first place, the grease applied to the O-ring is not so large that it reaches the flow rate adjusting part. However, as will be described in detail later, the shape of the portion where grease is attached on the outer peripheral surface of the valve shaft is a tongue shape, and when the valve shaft is moved forward and backward, the grease is concentrated and supplied to the tip of the tongue shape. As a result, it was found that the tip of the tongue shape was elongated and eventually the grease penetrated into the flow rate adjusting part at the tip of the valve shaft. Therefore, the valve shaft at a position between the retracted portion and the flow control portion of the valve shaft, as Rukoto provided enlarged wall shaft diameter of the valve stem is enlarged stepwise, in order to form the enlarged diameter wall An obstacle groove is formed on the outer peripheral surface of the obstacle groove, and the side wall surface on the flow rate control unit side of the obstacle groove is used as a diameter-expanded wall. The position of the enlarged diameter wall is set to a position outside the valve bearing even when the valve shaft is retracted to a position where the fuel gas reaches the maximum flow rate. In this way, when the elongated tongue-shaped tip reaches the enlarged diameter wall, the flow of grease that had been directed to the flow control unit until then is blocked by the enlarged diameter wall and changes direction in the lateral direction. The grease is a than arrived from concentrating on the tip portion of the tongue-shaped to the flow control unit, the absolute since only a small amount of grease that is redirected to be flow in the enlarged diameter wall failure groove of grease to be supplied It will not reach the flow control unit over the enlarged diameter wall. In addition, since the valve shaft on the tip side of the diameter-expanded wall is not drawn into the valve bearing, it is not drawn into the valve bearing and grease does not adhere to it. Therefore, even if the valve shaft is repeatedly moved forward and backward, the grease applied to the O-ring does not penetrate to the flow rate control unit at the tip of the valve shaft. As a result, even when the gas flow rate control valve mounted on the gas appliance is used for a long period of time, the gas flow rate of the fuel gas can be finely controlled within a small flow rate range.

Further, in the gas flow rate control valve of the present invention in which an obstacle groove is formed on the outer peripheral surface of the valve shaft, when the valve shaft is retracted to the position where the fuel gas reaches the maximum flow rate, it is opposite to the enlarged wall of the obstacle groove. The side wall surface may be pulled inside the valve bearing .

As will be described in detail later, when the valve shaft is retracted, the grease adhering to the outer peripheral surface of the valve shaft is scraped off by the end surface of the valve bearing, so that a flow of grease is generated toward the flow rate control unit. Therefore, if fuel gas it is devised side wall surface of the enlarged diameter wall opposite is drawn inside the valve bearing when retracting the valve stem to a position where the maximum flow rate, the fuel gas becomes maximum flow position Grease is no longer scraped off at the end face of the valve bearing before the valve shaft retracts . Therefore, the flow of grease toward the flow rate control unit is suppressed, and it is possible to more reliably prevent the grease from entering the flow rate control unit.

It is a perspective view which showed the appearance shape of the gas flow rate control valve 1 of this Example. It is an exploded view which shows the internal structure of the gas flow rate control valve 1 of this Example. It is explanatory drawing which showed how the gas flow rate control valve 1 of this Example moves a valve body 10 forward and backward, and controls a gas flow rate. The reason why it becomes difficult to finely control the gas flow rate due to the infiltration of 13 g of grease into the flow rate control unit 12 on the tip side of the valve shaft 91 when the conventional gas flow rate control valve 9 is used for a long period of time is shown. It is an explanatory diagram. It is explanatory drawing which showed the shape of the valve body 10 used in the gas flow rate control valve 1 of this Example. It is explanatory drawing which showed the reason which it is possible to prevent the grease 13g from entering into the flow rate control part 12 on the tip end side of the valve shaft 11 in the gas flow rate control valve 1 of this Example. It is explanatory drawing of the reason why a part of the obstacle groove 14 formed in the valve shaft 11 has entered into the valve bearing 22 when the gas flow rate control valve 1 of this Example is set to the maximum flow rate .

FIG. 1 is a perspective view showing an external shape of the gas flow rate control valve 1 of this embodiment. As shown, the gas flow rate control valve 1 of this embodiment includes a main body case 20, a valve hole plate 30 attached to the main body case 20, a main valve unit 40 attached to the valve hole plate 30, and a main body. It includes a valve body 10 that is inserted into the valve bearing 22 of the case 20 and can move forward and backward, and a drive unit 50 that moves the valve body 10 forward and backward. As shown by the arrow of the thick alternate long and short dash line in the figure, the fuel gas flows into the inside of the main valve unit 40 from the inflow pipe 40p erected on the side surface of the main valve unit 40 and is formed in the valve hole plate 30. After flowing into the inside of the main body case 20 through a valve hole (not shown), it flows out from the outflow pipe 20p erected on the side surface of the main body case 20. Then, the gas flow rate of the fuel gas can be controlled by moving the valve body 10 forward and backward using the drive unit 50.

FIG. 2 is an exploded assembly view showing the internal structure of the gas flow rate control valve 1 of this embodiment. As shown in the figure, the main body case 20 has a hollow cylindrical body portion 21, a valve chamber 21a formed inside the body portion 21, and a hollow cylinder provided coaxially with the body portion 21. It includes a valve bearing 22 having a shape and a hollow outflow pipe 20p erected from the body 21 toward the side.

Further, the valve hole plate 30 is a substantially disk-shaped member having a circular valve hole 31 formed in the center, and a disk-shaped inlay portion 30a projecting from one side is used as a valve chamber of the main body case 20. By inserting it into the 21a, it can be assembled to the main body case 20.

The valve body 10 includes a cylindrical valve shaft 11 and a tapered flow rate control unit 12 formed on the tip end side of the valve shaft 11, and the end portion on the opposite side to the flow rate control unit 12 has a valve body 10. A fitting portion 11h to be fitted to the drive unit 50 is formed. Further, a rubber O-ring 13 is fitted in the middle position on the outer peripheral surface of the valve shaft 11, and further, the outer peripheral surface of the valve shaft 11 goes around the outer peripheral surface of the valve shaft 11 at a position on the front side of the flow rate control unit 12. An obstacle groove 14 is bored. The outer diameter of the valve shaft 11 is smaller than the inner diameter of the valve bearing 22 formed in the main body case 20, and when the valve shaft 11 is inserted into the valve bearing 22, the valve shaft 11 is moved forward and backward in the valve bearing 22. It becomes possible. Further, airtightness is maintained by the O-ring 13 between the outer peripheral surface of the valve shaft 11 and the inner peripheral surface of the valve bearing 22. Then, when the valve body 10 is inserted into the valve bearing 22 with the valve hole plate 30 assembled to the main body case 20, the tip of the flow rate control unit 12 formed on the tip side of the valve shaft 11 becomes the valve hole plate 30. It is designed to be inserted into the valve hole 31.

The drive unit 50 has a built-in electric motor, a gear mechanism, and the like (not shown), and when the electric motor is driven, the valve body 10 can be moved forward and backward via the fitting portion 11h of the valve body 10. There is. In this embodiment, the drive unit 50 corresponds to the "drive unit" in the present invention.

The main valve unit 40 has a structure in which the main valve 42 is assembled to the main valve case 41, and the valve shaft 42a of the main valve 42 projects into the main valve chamber 41a formed inside the main valve case 41. It is in a state. Further, the inflow pipe 40p communicates with the main valve chamber 41a. Further, as described above, the valve hole plate 30 is provided with an in-row portion 30a for attaching the main body case 20, but it is also shown on the surface opposite to the side on which the in-row portion 30a is provided. The in-row part that does not work is projected. The main valve unit 40 is attached to the valve hole plate 30 so as to fit the inner circumference of the main valve chamber 41a into the inlet portion. When the main valve 42 is opened, the valve shaft 42a is retracted and the tip portion 42b of the valve shaft 42a is separated from the valve hole 31 of the valve hole plate 30, but when the main valve 42 is closed, the valve is valved. The shaft 42a protrudes, and the tip portion 42b of the valve shaft 42a comes into contact with the valve hole plate 30 to close the valve hole 31. Further, the thickness of the valve hole plate 30 is such that even if the flow rate control unit 12 of the valve shaft 11 is inserted into the valve hole 31 in a state where the tip portion 42b of the valve shaft 42a closes the valve hole 31, the flow rate control unit The thickness of the tip of 12 is set so as not to interfere with the tip portion 42b of the valve shaft 42a.

FIG. 3 is an explanatory diagram showing an operation in which the gas flow rate control valve 1 of the present embodiment controls the gas flow rate by moving the valve shaft 11 forward and backward. FIG. 3A shows a state in which the valve shaft 11 is most advanced. In this state, the flow rate control unit 12 formed on the tip end side of the valve shaft 11 penetrates into the valve hole 31 and closes the valve hole 31, resulting in a fully closed state in which the fuel gas cannot pass through the valve hole 31. Become. However, as described above, since the flow rate control unit 12 has a tapered shape, when the valve shaft 11 is retracted, the outer peripheral surface of the flow rate control unit 12 is separated from the inner peripheral surface of the valve hole 31, and the flow rate control unit 12 is separated. A gap is formed between the valve hole 31 and the valve hole 31, and the fuel gas passes through the gap.

FIG. 3B shows a state in which a gap is formed between the flow rate control unit 12 and the valve hole 31 due to the valve shaft 11 retracting. Further, the arrow shown by the thick broken line in the figure shows how the fuel gas flows through the gap formed between the flow rate control unit 12 and the valve hole 31. Since the gap between the flow rate control unit 12 and the valve hole 31 is small, the flow rate of the fuel gas passing through the gap is also small, so that a gas stove can be in a so-called toro fire state. Further, if the valve shaft 11 is further retracted, the gap between the flow rate control unit 12 and the valve hole 31 is increased and the flow rate of the fuel gas is increased. Conversely, if the valve shaft 11 is advanced, the flow rate is increased. The gap between the control unit 12 and the valve hole 31 becomes smaller, and the flow rate of the fuel gas decreases. Therefore, by moving the valve shaft 11 forward and backward, the flow rate of the fuel gas can be finely controlled in a small flow rate range. Further, since the airtightness is maintained between the inner peripheral surface of the valve bearing 22 and the valve shaft 11 by the O-ring 13, even if the valve shaft 11 is moved forward and backward, the space between the valve shaft 11 and the valve bearing 22 is maintained. No fuel gas leaks from the bearing.

FIG. 3C shows a state in which the valve shaft 11 is retracted to the maximum. In this state, the gap between the flow rate control unit 12 and the valve hole 31 is the largest. As a result, as shown by the thick broken line arrow in the figure, the flow rate of the fuel gas passing through the gap is also maximized. Further, since the position of the valve bearing 22 does not move even if the valve shaft 11 is moved forward and backward, when the valve shaft 11 is moved forward and backward, the portion where the valve shaft 11 is housed in the valve bearing 22 moves. That is, in the fully closed state shown in FIG. 3A, the portion of the valve shaft 11 close to the fitting portion 11h is housed in the valve bearing 22, but in the fully open state shown in FIG. 3C. The portion close to the flow rate control unit 12 is pulled into the valve bearing 22 and is accommodated in the valve bearing 22. Further, when the fully opened state shown in FIG. 3C is changed to the fully closed state shown in FIG. 3A, the portion of the valve shaft 11 near the fitting portion 11h is pulled into the valve bearing 22. It is in a state of being housed in the valve bearing 22. Therefore, the portion of FIG. 3C in which the valve shaft 11 is shaded is the portion that can be drawn into the valve bearing 22 (that is, the pull-in portion 11a). Further, the length of the valve shaft 11 is formed to be longer than that of the retractable portion 11a, and the flow rate control unit 12 is a valve shaft outside the retractable portion 11a (thus, it is not drawn into the valve bearing 22). It is provided at the tip thereof via 11.

Here, as is well known, the O-ring 13 is assembled with 13 g of grease applied. Therefore, 13 g of grease is attached to the inner peripheral surface of the valve bearing 22, and 13 g of grease is also attached to the retracted portion 11a, which is a portion where the valve shaft 11 can be drawn into the valve bearing 22. it is conceivable that. However, it is unlikely that 13 g of grease adheres to the flow rate control unit 12 provided at a position away from the lead-in unit 11a. However, in reality, 13 g of grease applied to the O-ring 13 is carried to the flow rate control unit 12 provided at a position away from the pull-in portion 11a while advancing and retreating the valve shaft 11, and the flow rate control unit It has been found that the gap between 12 and the valve hole 31 may be narrowed. This point will be described in detail below.

FIG. 4 is an explanatory diagram of a mechanism in which 13 g of grease adhering to the O-ring 13 is carried to the flow rate control unit 12. FIG. 4A shows the gas flow rate control valve 1 in a state immediately after the conventional valve shaft 91 is assembled (that is, a state before the valve shaft 91 is moved forward and backward). For convenience of explanation, the surface of the valve shaft 91 is displayed in a state where the surface of the valve shaft 91 is exposed by breaking the valve bearing 22 above the central shaft of the valve shaft 91. Further, it is considered that 13 g of grease adheres between the valve bearing 22 and the valve shaft 91 at the stage of inserting the valve shaft 91 coated with the grease 13 g into the valve bearing 22 for assembling, but for convenience of understanding. , FIG. 4A shows that the grease 13g is attached near the O-ring 13 but not at a location away from the O-ring 13.

When the valve shaft 91 is retracted from the state shown in FIG. 4A (here, the fully closed state), the O-ring 13 is also retracted in the valve bearing 22. At this time, the grease 13g adhering to the inner peripheral surface of the valve bearing 22 is dragged by the retracting O-ring 13 and is stretched in a tongue shape in some places. FIG. 4B shows a state in which the valve shaft 91 is retracted to the fully opened state in order to make it easy to understand that the grease 13 g is stretched in the shape of a tongue. Further, since there is only a slight gap between the inner peripheral surface of the valve bearing 22 and the outer peripheral surface of the valve shaft 91, 13 g of grease adhering to the inner peripheral surface of the valve bearing 22 will soon be released from the outer peripheral surface of the valve shaft 91. Also adheres to.

After that, when the valve shaft 91 was advanced in order to reduce the gas flow rate of the fuel gas, as shown in FIG. 4C, until then, it had existed in the valve bearing 22 and 13 g of grease had adhered to it. The portion appears outside the valve bearing 22. However, at this stage, the portion where the grease 13g is attached to the valve shaft 91 is the portion that was previously drawn into the valve bearing 22, so the grease extends to the outside of the drawing portion 11a shown in FIG. 3C. 13g is not being carried.

However, as shown in FIG. 4C, when the valve shaft 91 was to be retracted while the portion where the grease 13 g was attached to the valve shaft 91 was outside the valve bearing 22, the grease adhered to the valve shaft 91. 13 g of grease is scraped off by the end face of the valve bearing 22. The black arrow shown in FIG. 4C indicates a portion where the end face of the valve bearing 22 is about to scrape out 13 g of grease adhering to the valve shaft 91. Of course, the grease 13g adhering to the valve shaft 91 is a part of the grease 13g existing in the gap between the valve shaft 91 and the valve bearing 22 and is pulled out by moving to the valve shaft 91. It does not adhere thickly to the surface of 91. However, when the valve shaft 91 moves forward and backward, it is inevitable that the valve shaft 91 swings around to some extent. Therefore, when the valve shaft 91 is retracted, the grease adhering to the valve shaft 91 is unavoidable. A part of 13 g will be scraped off by the end face of the valve bearing 22. Then, the scraped out grease 13g is more easily flowed toward the portion where the grease 13g has already adhered than toward the portion where the grease 13g has not yet adhered on the valve shaft 11, so that the scraped out grease is scraped out. 13 g of the grease is supplied toward the tip of the tongue shape. As a result, the tip of the tongue shape is intensively stretched.

In FIG. 4 (d), as a result of retracting the valve shaft 91 from the state shown in FIG. 4 (c), a part of the grease 13 g is scraped off by the end face of the valve bearing 22, and the tongue shape is stretched. It is shown. When the valve shaft 91 is advanced from this state, a tongue-shaped portion to which 13 g of grease is attached appears outside the valve bearing 22 as shown in FIG. 4 (e). The tongue shape at this time is such that a part of the grease 13 g is scraped out when the valve shaft 91 is retracted, and the tip portion of the tongue shape is elongated and extended. Then, when the valve shaft 91 is retracted again from this state, a part of the grease 13 g adhering to the valve shaft 91 is scraped off by the end face of the valve bearing 22, and as a result, the tongue-shaped portion to which the grease 13 g is attached becomes more elongated. Stretch. The black arrow shown in FIG. 4E indicates a portion where the end face of the valve bearing 22 writes out a part of the grease 13g when the valve shaft 91 is retracted. Further, FIG. 4 (f) shows a state after the valve shaft 91 is retracted.

In this way, in the conventional gas flow rate control valve 1, when the valve shaft 91 is repeatedly moved forward and backward in order to control the gas flow rate, 13 g of grease applied to the O-ring 13 is gradually scraped outward. To go. Then, it was found that 13 g of the scraped grease was concentratedly supplied to the tip of the tongue shape, and as a result, the tip of the tongue shape was elongated and eventually carried to the flow rate control unit 12. That is, although the amount of grease 13g applied to the O-ring 13 is small, the reason why the grease 13g can reach the flow rate control unit 12 away from the valve bearing 22 is that the grease 13g reaches the tongue-shaped tip. It is thought that it is being supplied in a concentrated manner. When the gas appliance is used for a long period of time, it may be difficult to finely control the gas flow rate in a small gas flow rate range. It is considered that this is because the gap between the control unit 12 and the valve hole 31 is narrowed. Therefore, in the gas flow rate control valve 1 of this embodiment, the shape of the valve body 10 is as follows in order to prevent the grease 13 g from being carried to the flow rate control unit 12.

FIG. 5A is an explanatory view showing the outer shape of the valve body 10 built in the gas flow rate control valve 1 of this embodiment. Further, FIG. 5B also shows the outer shape of the conventional valve body 90 for reference. As is clear from a comparison between the valve body 10 of the present embodiment shown in FIG. 5 (a) and the conventional valve body 90 shown in FIG. 5 (b), the valve body 10 of the present embodiment has a flow rate. An obstacle groove 14 having a rectangular cross section is bored on the outer peripheral surface of the valve shaft 11 on the front side of the control unit 12 in a circumferential shape. Therefore, when the left and right side walls 14b and 14c are viewed from the bottom 14a of the obstacle groove 14, the portion where the shaft diameter of the valve shaft 11 is reduced (that is, the bottom 14a of the obstacle groove 14) is the portion of the side walls 14b and 14c. The shaft diameter of the valve shaft 11 is expanded in a stepwise manner. In the present embodiment, among the left and right side walls 14b and 14c, the side wall 14b on the tip end side (the side on which the flow rate control unit 12 is formed) corresponds to the "diameter expansion wall" in the present invention. Therefore, in the following, the side wall 14b on the tip side will be referred to as a diameter-expanded wall 14b. As shown in FIG. 5A, the enlarged diameter wall 14b is formed on the outside of the retractable portion 11a. Therefore, as shown in FIG. 3C, the diameter-expanded wall 14b is not pulled into the valve bearing 22 even when the valve shaft 11 is most pulled in.

On the other hand, since the side wall 14c on the opposite side of the diameter-expanded wall 14b is formed at the position inside the pull-in portion 11a, when the valve shaft 11 is pulled in most, the side wall 14c is pulled into the valve bearing 22. It will be in a bearing state. In this embodiment, the side wall 14c is formed inside the retractable portion 11a, but the side wall 14c may also be formed outside the retractable portion 11a in the same manner as the enlarged diameter wall 14b. ..

FIG. 6 is an explanatory diagram of the reason why it is possible to prevent the grease 13 g of the O-ring 13 from entering the flow rate control unit 12 by providing the enlarged diameter wall 14b on the valve shaft 11 of the valve body 10. Even in the case of the valve body 10 of the present embodiment provided with the enlarged diameter wall 14b, as described above with reference to FIG. 4, when the valve shaft 11 is repeatedly moved forward and backward, the grease 13 g applied to the O-ring 13 becomes a valve. It is scraped off from the end face of the bearing 22 and gradually carried toward the flow control unit 12. As a result, the tip of the tongue-shaped portion to which the grease 13 g is attached gradually extends toward the flow rate control unit 12.

However, in the gas flow rate control valve 1 of this embodiment, the diameter expansion wall 14b is formed on the valve shaft 11 on the front side of the flow rate control unit 12. Therefore, the flow of the grease 13g extending toward the flow rate control unit 12 is changed to a lateral flow by the diameter-expanding wall 14b. The arrow shown by the thick broken line in FIG. 6 represents the flow of the grease 13 g changed by the enlarged diameter wall 14b. Then, as described above with reference to FIG. 4, the grease 13 g can reach the flow rate control unit 12 as a result of being concentratedly supplied to the tip of the tongue shape, but the amount of the grease 13 g itself is not so large. Therefore, as shown in FIG. 6, if the flow direction of the grease 13g is changed in the lateral direction on the diameter-expanded wall 14b, the grease 13g no longer penetrates the flow control unit 12 beyond the diameter-expanded wall 14b. There is no such thing. As a result, the gas flow rate control valve 1 of the present embodiment can finely control the gas flow rate in a small gas flow rate range even when the valve shaft 11 is repeatedly moved forward and backward for a long period of time.

In the gas flow rate control valve 1 of the present embodiment described above, the width of the obstacle groove 14 may be the same as or larger than the width of the groove into which the O-ring 13 is fitted. By doing so, it is considered that the grease 13 g applied to the O-ring 13 can be accommodated in the obstacle groove 14 with a margin, so that it is possible to reliably prevent the grease 13 g from reaching the flow rate control unit 12. It becomes.

Further, as described above with reference to FIG. 5A, the gas flow rate control valve 1 of the present embodiment is formed on the outside of the lead-in portion 11a with respect to the diameter-expanded wall 14b. The side wall 14c on the opposite side is formed inside the retractable portion 11a. By doing so, it is possible to prevent the grease 13 g adhering to the valve shaft 11 from being scraped off by the end face of the valve bearing 22 when the valve shaft 11 is retracted.

FIG. 7 is an explanatory view showing the reason why the scraping of grease 13g by the end surface of the valve bearing 22 can be suppressed by forming the side wall 14c on the opposite side of the diameter-expanded wall 14b inside the retractable portion 11a. FIG. 7A shows a state in which the valve shaft 11 is retracted with the side wall 14c protruding outside the valve bearing 22. In this state, the end face of the valve bearing 22 scrapes out 13 g of grease adhering to the valve shaft 11 at the portion indicated by the black arrow in the drawing. However, as shown in FIG. 7B, when the valve shaft 11 is further retracted and the side wall 14c is at the same position as the end surface of the valve bearing 22, even if the valve shaft 11 is retracted further, FIG. 7 As shown in (c), since the obstacle groove 14 slips into the inside of the valve bearing 22, the grease 13 g is not scraped off at the end face of the valve bearing 22. That is, if the side wall 14c is formed at a position inside the retracting portion 11a as in the valve body 10 of this embodiment, the position shown in FIG. 7B to the position shown in FIG. 7C. Can retract the valve shaft 11 without scraping out 13 g of grease on the end face of the valve bearing 22. As a result, it is possible to suppress the scraping of 13 g of grease by the end face of the valve bearing 22, so that even if the valve shaft 11 is repeatedly moved forward and backward for a long period of time, the 13 g of grease enters the flow control unit 12 and gas. It is possible to avoid a situation in which fine adjustment of the flow rate is hindered.

Having described the gas flow control valve 1 of this embodiment, the present invention is not limited to the embodiments described above, it is possible to implement in various forms without departing from the scope thereof.

1 ... Gas flow control valve, 10 ... Valve body, 11 ... Valve shaft, 11a ... Retractable part,
12 ... Flow control unit, 13 ... O-ring, 13g ... Grease,
14 ... Obstacle groove, 14a ... Bottom, 14b ... Expanded wall, 14c ... Side wall,
15 ... Obstacle wall, 15a ... Expanded wall, 20 ... Body case, 21a ... Valve chamber,
22 ... Valve bearing, 30 ... Valve hole plate, 31 ... Valve hole, 40 ... Main valve unit,
42 ... main valve, 50 ... drive unit.

Claims (2)

In a gas flow control valve that is used for a gas appliance that burns fuel gas and controls the gas flow rate of the fuel gas.
A valve shaft formed in a cylindrical shape and
A flow control unit formed in a tapered shape on the tip side of the valve shaft,
A valve hole into which the tip side of the flow control unit is inserted,
A valve bearing that holds the valve shaft in a state where it can move forward and backward in the axial direction by inserting the valve shaft, and
An O-ring coated with grease while keeping airtightness between the outer peripheral surface of the valve shaft and the inner peripheral surface of the valve bearing,
It is provided with a drive unit that reduces the gas flow rate of the fuel gas by advancing the valve shaft and increases the gas flow rate of the fuel gas by retreating the valve shaft.
In the valve shaft, the shaft diameter of the valve shaft is stepped at a position between the pull-in portion, which is a portion drawn into the valve bearing by moving the valve shaft forward and backward, and the flow rate control portion. A diameter-expanding wall is formed to expand the diameter .
The enlarged diameter wall is a side wall surface of the obstacle groove formed on the outer peripheral surface of the valve shaft on the flow rate control unit side, even when the valve shaft is retracted to a position where the maximum flow rate of the fuel gas is reached. , A gas flow rate control valve characterized in that it is formed at a position outside the valve bearing. In the gas flow rate control valve according to claim 1,
The side wall surface of the obstacle groove opposite to the enlarged diameter wall is in a state of being pulled into the valve bearing when the valve shaft retracts to a position where the fuel gas reaches the maximum flow rate. Gas flow control valve.

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