JP2006077901A - On-off valve structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-off valve structure with a a valve shaft supporting bush free of exposure to a high temperature exceeding a heat resistance limit even when high temperature fluid distributes. <P>SOLUTION: The on-off valve structure 1 is installed in a pipe body 2 in which the high temperature fluid distributes. The on-off valve structure 1 comprises a valve element 3 having a valve shaft 4 and the bush 8 arranged on the side of the pipe body 2 for supporting the valve shaft 4. A cooling medium passage 12 is formed between the pipe body 2 and the bush 8. A shielding member 10 is installed between the pipe body 2 and the bush 8. Used cooling medium which distributes in the cooling medium passage 12 is travelling air or engine cooling water. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an on-off valve structure that is installed in a pipe through which a high-temperature fluid flows and controls the flow of the high-temperature fluid.

Conventionally, an engine exhaust system catalyst may be disposed in an exhaust path immediately after an engine exhaust manifold. However, when the engine is operated at a high speed and high load, for example, very high temperature exhaust gas flows through the exhaust path immediately after the exhaust manifold. When very high temperature exhaust gas is supplied to the catalyst in this way, the catalyst may be deteriorated by heat. Therefore, conventionally, when a very high temperature exhaust gas is discharged, such as when a catalyst bypass path is formed and the engine is operated at a high speed and high load, such a high temperature exhaust gas is passed through the catalyst bypass path. Measures are taken to prevent deterioration of the catalyst due to heat.

  FIG. 1 is an explanatory diagram showing a schematic configuration of an exhaust system 50 having such a catalyst bypass path. The exhaust system 50 includes a catalyst 52 in an exhaust pipe 51 through which exhaust gas discharged from the engine side flows. Further, a catalyst bypass pipe 53 that bypasses the exhaust pipe 51 is provided. A valve body 54 is incorporated in the catalyst bypass pipe 53. The on-off valve 54 is driven by an actuator 55 controlled by the CPU 56. The CPU 56 refers to the engine speed, load state, engine exhaust temperature, etc., and when it is determined that the temperature of the exhaust gas exhausted from the engine exceeds a predetermined value, opens the valve body 54, Control is performed so that hot exhaust gas flows into the catalyst bypass pipe 53 and does not flow into the exhaust pipe 51.

That is, in such an exhaust system 50, when the engine is at a low speed and a light load or the like, and the temperature of the exhaust gas is not so high, the valve body 54 is closed and the exhaust gas is caused to flow into the exhaust pipe 51 to thereby form a catalyst. Then, it is caused to flow to the exhaust downstream side. On the other hand, when the engine is at high speed and high load, etc., and the temperature of the exhaust gas is high, the valve body 54 is opened to allow the exhaust gas to flow into the catalyst bypass pipe 53 and then flow downstream. . Here, such a valve body 54 includes a valve shaft, and opens and closes with the valve shaft as a fulcrum. Such a valve shaft is rotatably supported by a bush incorporated in the bearing. Here, as the material of the bush, a material obtained by blending expanded graphite with SUS material is often used. If such a material is used, the valve shaft is firmly supported by the expansion of the expanded graphite as the temperature rises, and a good turning property can be obtained.
A system similar to the exhaust system 50 described above is also disclosed in Patent Document 1.

JP-A-5-44449

  However, the conventional exhaust system 50 has the following problems related to the valve body 54. That is, the valve body 54 is supported by the bush as described above, and the heat resistance temperature of the expanded graphite constituting the bush is about 700 ° C. at the maximum. On the other hand, the temperature of the hot exhaust gas discharged from the engine reaches around 900 ° C. Therefore, when the engine is operated at a high speed and a high load, hot exhaust gas flows into the catalyst bypass pipe 53, and the heat of the exhaust gas is transmitted to the bush, the expanded graphite constituting the bush exceeds the heat resistance limit. It could be damaged and was a problem.

  Accordingly, an object of the present invention is to provide an on-off valve structure in which a bush supporting a valve shaft is not exposed to a high temperature exceeding the heat resistance limit even when a high-temperature fluid flows.

  An on-off valve structure according to the present invention for achieving such an object is an on-off valve structure installed in a pipe through which a high-temperature fluid flows, and is provided on a side of the pipe with a valve shaft and a valve shaft. And a bush that supports the valve shaft, and a refrigerant passage is formed between the tube and the bush.

  In such an on-off valve structure, it is desirable that the refrigerant passage has a configuration in which a cross-sectional area decreases from the upstream side toward the valve shaft, and a throat portion is formed. Moreover, it can be set as the structure which installed the shielding member between the said tubular body and the said bush. Further, in such an on-off valve structure, a casing is formed which communicates with the tube body and forms a bearing for the valve shaft. The bush is built in the casing and shielded between the tube body and the bush. It can also be set as the structure which installed the member. Further, as the refrigerant, traveling wind or engine cooling water can be used.

  The on-off valve structure having the above-described configuration can be used for any pipe as long as a high-temperature fluid circulates. For example, it can be used for an exhaust pipe for catalyst bypass in an internal combustion engine. it can.

  According to the present invention, since the refrigerant is circulated between the pipe body through which the high-temperature fluid flows and the bush supporting the valve shaft, the bush is damaged by the heat of the fluid flowing through the pipe body. There is no.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 2 is an explanatory diagram showing a configuration of the on-off valve structure 1 installed in the pipe body 2 through which the high-temperature fluid flows. The pipe body 2 is a catalyst bypass pipe that bypasses the catalyst installed in the exhaust pipe disposed in the exhaust path immediately after the exhaust manifold of the engine. The tube body 2 is provided with a shaft hole 2a for allowing the valve shaft 4 provided by the valve body 3 to pass therethrough. Further, a cylindrical body 2b is connected to the tubular body 2 at a portion where the shaft hole 2a is formed, and casings 6a and 7a constituting the bearings 6 and 7 are provided on the distal end side of the cylindrical body 2b. ing. That is, these casings 6 a and 7 a communicate with the tube body 2. In the casings 6a and 7a, a bush 8 made of a material obtained by mixing SUS material with expanded graphite is incorporated.

  The valve body 3 is attached to the tube body 2 through the valve shaft 4 through the shaft hole 2a and the cylinder body 2b, and further supported by a bush 8 built in the casings 6a and 7a. Here, one casing 6a is hermetically sealed, but the other casing 7a has an opening 7a1, from which one end side 4a of the valve shaft 4 is led out of the casing 7a. ing. A crank 9 for opening and closing the valve body 3 is connected to one end side 4a of the valve shaft 4 led out of the casing 7a in this way. The crank 9 opens and closes the valve body 3 based on a command from a CPU (not shown) by an actuator (not shown).

  Inside the casings 6a and 7a, as shown in the figure, a shielding member 10 is mounted on the side close to the cylindrical body 2b. The shielding member 10 is made of a highly heat insulating plate and is fixed to the valve shaft 4. In addition, fins 11 are attached to the casings 6 a and 7 a so as to be parallel to the side wall of the pipe body 2. As shown in the figure, the fin 11 has a cross-sectional area that decreases from the upstream side toward the valve shaft 4 from the upstream side of the refrigerant passage 12, and a throat portion 12 a is formed in the vicinity of the valve shaft 4.

  With the above-described configuration, the on-off valve structure 1 forms the refrigerant passage 12 between the tube body 1 and the casings 6 a and 7 a, that is, between the tube body 1 and the bush 8. Here, in this embodiment, traveling wind generated when the vehicle travels is introduced into the coolant passage 12 as a coolant. For this reason, the on-off valve structure 1 is disposed at a position close to the bottom surface of the vehicle so that vehicle speed wind can be easily introduced.

  The on-off valve structure 1 configured as described above opens the on-off valve 3 through an actuator (not shown) and a crank 9 based on an instruction from a CPU (not shown) when the engine is operated at a high speed and high load. Is done. Thereby, the high temperature exhaust gas which avoided the inflow to a catalyst side flows in into the pipe body 2 which is a catalyst bypass pipe.

  Here, the tube 2b is interposed between the tube 2 and the bush 8, and the tube 2 and the bush 8 are separated by a distance corresponding to at least the height of the tube 2b. . For this reason, the influence of the heat which the high temperature exhaust gas which distribute | circulates the inside of the pipe body 2 can be relieve | moderated. Moreover, since the shielding member 10 which interrupts | blocks the heat from the pipe body 2 side is interposed between the pipe body 2 and the bush 8, the influence of the heat with respect to the bush 8 is eased also by this.

  Further, as the vehicle travels, traveling wind is introduced into the refrigerant passage 12 as indicated by an arrow 13. Here, the refrigerant passage 12 is reduced in cross-sectional area from the upstream side toward the valve shaft 4 by the fins 11, and the throat portion 12 a is formed in the vicinity of the valve shaft 4, so that the wind speed increases near the valve shaft 4. Since a large amount of air circulates, the cooling effect is enhanced.

  As described above, since the on / off valve structure 1 is provided with a measure for reducing or cooling the influence of the heat of the high-temperature exhaust gas flowing through the tube 2, the bush 8 is heated. It is possible to reduce the possibility of being damaged by the influence.

Next, Embodiment 2 of the present invention will be described with reference to FIG. The on-off valve structure 20 of the second embodiment is different from the on-off valve structure 1 of the first embodiment in that the on-off valve structure 20 of the second embodiment is not provided with the on-off valve structure 1 of the first embodiment. The introduction side pipe 21, the discharge side pipe 22, and the cooling water tank 23 are provided.
In the on-off valve structure 20 of the second embodiment, the same components as those of the on-off valve structure 1 of the first embodiment are denoted by the same reference numerals in the drawings, and detailed description thereof is omitted.

  An engine cooling water circulation system 24 including an introduction side pipe 21, a discharge side pipe 22, and a cooling water tank 23 is incorporated in an engine cooling system including a radiator and the like. That is, a donut-shaped cooling water tank 23 is mounted around the cylinder 2 b, and the introduction side pipe 21 is connected to a line through which the engine cooling water flows to draw the engine cooling water into the cooling water tank 23. Further, the coolant is returned to the line through which the engine coolant flows again through the discharge side pipe 22 connected to the coolant tank 23.

With such a configuration, it is possible to further enhance the effect of not transferring the heat of the high-temperature exhaust gas flowing through the tube body 2 to the bush 8.
When the engine cooling water is drawn into the cooling water tank 23, it is desirable to take measures such as replacing it with a radiator having a large heat capacity so as not to lower the cooling efficiency of the engine body. Further, in this embodiment, the fins 11 are mounted in the same manner as the on-off valve structure 1 of the first embodiment, and the cooling by the traveling wind is used together. However, the fins 11 may be removed. Even in such a configuration, the tube body 2 and the bush 8 are disposed at a distance, and the shielding member 10 is disposed, and the engine cooling water circulation system 24 is provided. Damage due to heat can be avoided.

Next, Embodiment 3 of the present invention will be described with reference to FIG. The on-off valve structure 30 of the third embodiment is different from the on-off valve structure 1 of the first embodiment in that the on-off valve structure 30 of the third embodiment is not provided with the on-off valve structure 1 of the first embodiment and the spring 31 in the casing 7a. It is a point that is provided.
In addition, in the on-off valve structure 30 of the third embodiment, the same components as those of the on-off valve structure 1 of the first embodiment are denoted by the same reference numerals in the drawings, and detailed description thereof is omitted.

  As shown in FIG. 4, the spring 31 is built in the casing 7a so as to bias the shielding member 10 toward the cylindrical body 2b. By comprising in this way, the shielding member 10 can be closely_contact | adhered to the inner wall by the side of the cylinder 2b of the casing 7a. The reason why the shielding member 10 is brought into close contact with the inner wall of the casing 7a on the cylindrical body 2b side is as follows.

  As described above, the casing 7a communicates with the tube body 2 through the cylindrical body 2b. For this reason, the hot exhaust gas which has flowed into the tube body 2 flows into the casing 7a from the shaft hole 2a through the tube body 2b. Here, the casing 7a is provided with an opening 7a1 for leading one end side 4a of the valve shaft 4 to the outside of the casing 7a in order to connect the valve shaft 4 to the crank 9. For this reason, the exhaust gas that has flowed into the casing 7a may leak to the outside from the opening 7a1.

Therefore, in this embodiment, in order to prevent the exhaust gas from flowing into the casing 7a, the shielding member 10 blocks communication between the cylindrical body 2b and the casing 7a. In other words, the blocking member 10 is used not only to block heat from the bush 8 but also to block outflow of exhaust gas from the tube body 2.
Unlike the casing 7a, the casing 6a side is not provided with an opening corresponding to the opening 7a1, and the casing 6a itself has a hermetically sealed structure. is there.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited to them. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope. For example, in the above embodiment, the valve body is a butterfly valve, but any type of valve can be adopted as long as it is a valve that opens and closes around a valve shaft, such as a swing valve. it can. Further, a material having high heat insulating properties may be arranged around the valve shaft 4 to reduce the influence of heat on the bush 8.

It is explanatory drawing which shows schematic structure of the exhaust system which has a catalyst bypass path | route. It is explanatory drawing which shows the structure of the on-off valve structure of Example 1. FIG. It is explanatory drawing which shows the structure of the on-off valve structure of Example 2. FIG. It is explanatory drawing which shows the structure of the on-off valve structure of Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 20, 30 On-off valve structure 2 Tubing body 2a Shaft hole 2b Tubular body 3 Valve body 4 Valve shaft 6, 7 Bearing 6a, 7a Casing 7a1 Opening 8 Bush 9 Crank 10 Shielding member 11 Fin 12 Cooling passage 12a Throat part 21 Introduction Side pipe 22 Discharge side pipe 23 Cooling water tank 24 Engine cooling water circulation system

Claims (7)

An on-off valve structure installed in a pipe through which a high-temperature fluid flows,
A valve body including a valve shaft; and a bushing disposed on a side of the tube body to support the valve shaft;
An on-off valve structure, wherein a refrigerant passage is formed between the tube and the bush. 2. The on-off valve structure according to claim 1, wherein the refrigerant passage has a cross-sectional area that decreases from an upstream side toward the valve shaft, and a throat portion is formed. The on-off valve structure according to claim 1 or 2, wherein a shielding member is installed between the tube body and the bush. The on-off valve structure according to any one of claims 1 to 3,
An opening and closing comprising a casing that communicates with the tubular body and forms a bearing for the valve shaft, the bushing is built in the casing, and a shielding member is installed between the tubular body and the bushing Valve structure. The on-off valve structure according to claim 1, wherein the refrigerant is traveling wind. The on-off valve structure according to claim 1, wherein the refrigerant is engine cooling water. The on-off valve structure according to any one of claims 1 to 6, wherein the pipe is an exhaust pipe for catalyst bypass in an internal combustion engine.

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