JP2010133385A - Throttle valve device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make an inside of a conduit high in pressure, to inhibit gas leak of a valve of a butterfly type or the like including a bearing of a valve shaft rotating a valve element, and to prevent wear of a seal part. <P>SOLUTION: The valve element 10 is disposed rotatably in a valve housing 2, and flow rate of a gas in the valve housing 2 is regulated by rotation of the valve element 10. The valve shaft 4 rotatably supporting the valve element 10 is supported by the bearings 7, 8 in the valve housing 2. The bearing 7 is sealed from an outside by a bearing housing 5. The bearing 8 has a structure enabling an exhaust gas to flow out to the outside, and is sealed by a seal ring 17 pressed by the bearing shaft 4 to prevent leak of the exhaust gas. The valve shaft 4 is pressed by keeping an inner pressure high by a communication path 21 introducing the exhaust gas into the bearing housing 5. The seal ring 17 is pressed by the bearing 8 with stronger pressing force thereby. Consequently, sealing capacity is increased, corresponding to the rise of the inner pressure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a throttle valve device that can be suitably used in an exhaust pipe passage of an internal combustion engine such as a diesel engine or a gasoline engine.

Conventionally, an exhaust pipe of an internal combustion engine may be provided with a throttle valve device such as an exhaust pressure adjusting valve, an exhaust brake valve, or an EGR (exhaust gas recirculation) cooler passage switching valve.
As such a throttle valve device, a butterfly type exhaust valve is known (for example, see Patent Document 1).
An example of such an exhaust valve is shown in FIG. 3 is a side view showing the exhaust valve, FIG. 4 is a cross-sectional view taken along line AA in FIG. 3, and FIG. 5 is an enlarged view of a portion surrounded by a circle indicated by reference numeral B in FIG.

As shown in FIGS. 3 to 5, a disc-like valve body 10 is disposed in an exhaust passage 3 through which exhaust gas (gas) flows in a circular valve housing 2 so that the rotation angle can be changed. The amount of the exhaust gas passing through the exhaust passage 3 is changed depending on the rotation angle of the valve body 10, thereby changing the flow rate of the exhaust gas flowing through the exhaust passage 3. Can be adjusted.
A valve shaft 4 passes through the central portion of the valve housing 2, and has a bottomed cylindrical shape at one of two outer peripheral portions of the valve housing 2 through which the valve shaft 4 passes. On the other hand, a sealed bearing housing (sealed member) 5 is provided, and on the other side, a cylindrical bearing housing 6 in a state opened to the outside of the valve housing 2 is provided.

Bush-shaped bearings 7 and 8 are held in the bearing housings 5 and 6, respectively, and both axial ends of the valve shaft 4 can be rotated to the valve housing 2 via the bearings 7 and 8. It is supported by. The opening portions at both ends of the valve housing 2 are connected to the upstream side and the downstream side of an exhaust pipe extending from the exhaust side of the engine (not shown), respectively, and the valve housing is a part of a conduit through which exhaust gas flows. . That is, the valve housing 2 is arranged in the middle of the exhaust pipe.
A disc-shaped valve body 10 for opening and closing the exhaust passage 3 is provided in a portion (a portion between the bearings 7 and 8) disposed in the exhaust passage 3 in the valve housing 2 of the valve shaft 4. Are attached by two screws. The valve shaft 4 is divided into one bearing 7 side and the other bearing 8 side, and the valve body 10 is arranged between the divided valve shafts 4 to thereby provide the valve body. A part of 10 may function as a valve shaft.

Further, one axial end portion (the right end portion in FIG. 1) of the valve shaft 4 penetrates the bearing housing 6 and protrudes outward from the bearing housing 6. A wire lever 12 is fastened by a nut 13 to an end portion of the valve shaft 4 protruding outward from the bearing housing 6. The wire lever 12 is connected to a locking portion 12a provided on the wire lever 12 at the other end of a wire to which an actuator (rotation drive means) (not shown) is connected at one end.
A spring receiver 14 is provided on the inner surface of the wire lever 12 (the surface facing the valve housing 2). Between the spring receiver 14 and the spring receiver 15 provided in the bearing housing 6, a biasing means is provided. The spring 16 (compression coil spring: urging means) is arranged in a compressed state.

Therefore, the urging force of the spring 16 is received by the valve shaft 4 via the spring receiver 14 and the wire lever 12, and the valve shaft 4 is urged in the direction of arrow F in FIG. 1 (right direction in FIG. 1). Yes. That is, the valve shaft 4 is urged from the end portion supported by the sealed bearing housing 5 toward the end portion supported by the open bearing housing 6.
The bearings 7 and 8 are radial bearings and restrict movement in a direction perpendicular to the axial direction of the valve shaft 4, but allow movement along the axial direction of the valve shaft 4.
As shown in FIG. 4, a flange 4 a is formed integrally with a portion of the valve shaft 4 near one of the bearings 8, and a seal ring ( Sealing means) 17 is provided. The seal ring 17 is disposed between the flange portion 4a of the valve shaft 4 and a bearing 8 that rotatably supports one axial end portion of the valve shaft 4.

Here, since the valve shaft 4 is urged in the direction of arrow F by the spring 16 as described above, the end surface 17a on the bearing 8 side of the seal ring 17 provided on the valve shaft 4 is the seal ring of the bearing 8. The end surface 8a on the 17th side is pressed through the flange 4a.
As a result, the portion where the end surface 17a of the seal ring 17 and the end surface 8a of the bearing 8 are in contact with each other serves as a seal surface, and the exhaust gas flowing through the exhaust passage 3 supports the projecting side of the valve shaft 4. Leakage from the inside to the outside of the valve housing 2 is prevented.

  And in such an exhaust valve 1, when the said actuator rotates the wire lever 12 via the said wire, the valve body 10 rotates and adjustment of the flow volume of the exhaust gas in the exhaust passage 3 is performed. It will be.

JP 2008-274895 A

  By the way, in the seal structure of the exhaust valve bearing portion as described above, if the biasing force of the spring that presses the seal ring against the bearing is weak, the valve body rotates to the closed side and the pressure on the upstream side of the valve body of the exhaust pipe is reduced. When the valve height increases, exhaust gas leaks from the cylindrical housing portion that houses the bearing through which the valve shaft passes. In this case, the outflow amount of the exhaust gas increases as the valve body of the exhaust valve rotates to the closed side and the upstream internal pressure in the exhaust valve increases.

  Therefore, in order to prevent the leakage of exhaust gas, it is preferable to increase the urging force by the spring. However, if the urging force of the spring is increased, wear and surface roughness at the contact portion between the seal ring and the end face of the bearing described above. The resistance at the sliding portion between the seal ring and the end face of the bearing increases. That is, the shaft sliding resistance of the valve shaft that rotates the valve body increases. Also, the sliding noise increases.

  Here, in the case of the structure in which the seal ring is pressed by the spring as described above, a substantially constant urging force acts on the seal ring regardless of the rotation angle of the valve body 10 and the internal pressure of the exhaust valve. The amount of outflow of exhaust gas increases as the valve body rotates to the closed side as described above and the internal pressure increases.

Here, when the biasing force of the spring is adjusted so that the leakage of the exhaust gas hardly occurs when the internal pressure is high, the seal ring is unnecessarily strongly pressed against the bearing when the internal pressure is low. And since the urging | biasing force is strong, wear and surface roughening will arise as mentioned above.
Therefore, it has been difficult to reduce the outflow amount of exhaust gas and to suppress wear and surface roughness of the seal ring, that is, to achieve both reduction of the exhaust gas outflow amount and prevention of wear of the seal ring and the like.

  The present invention has been made in view of the above circumstances, and includes a shaft that rotates a valve body, and in a structure in which the shaft passes through a conduit through which gas flows, while preventing leakage of exhaust gas and sealing the shaft An object of the present invention is to provide a throttle valve device that can suppress wear of a structural portion.

In order to achieve the object, the throttle valve device according to claim 1 includes a pipe through which a gas flows,
A valve body for adjusting the flow rate of the gas flowing through the pipe line by changing the rotation angle;
A valve shaft connected to the valve body and rotating the valve body;
A bearing that rotatably supports the valve shaft;
Provided between the pipe line and the bearing;
A seal member for preventing gas outflow from the bearing;
A throttle valve device comprising an urging means for applying a pressing force between the seal member and the bearing,
An accommodation portion in which one end portion of the valve shaft is accommodated, and a communication passage that communicates the accommodation portion and the upstream side of the valve body in the pipe line are provided.

In the first aspect of the present invention, when the valve body rotates in the direction in which the gas flow rate is reduced (closed direction) and the internal pressure on the upstream side from the valve body of the pipe line increases, the internal pressure increases due to the communication path. The internal pressure of the accommodating portion that communicates with the upstream side of the pipe and accommodates one end portion of the valve shaft is also increased.
As a result, the valve shaft is pressed from one end side where the accommodating portion is located to the other end side.
The pressing force acts between the bearing and the seal member in a state where the seal member and the bearing are biased by the biasing means. Further, when the valve shaft is pressed as described above, a pressing force is applied between the seal member and the bearing by the valve shaft.

In this case, a pressing force based on the urging force of the urging means and a pressing force based on the increased internal pressure act on the seal means and the bearing. Compared with the case where only the urging force of the urging means acts. As a result, the ability to prevent the outflow of gas increases.
Further, the pressing force based on the internal pressure increases as the internal pressure increases, and decreases as the internal pressure decreases.
Therefore, in a state where the internal pressure is high and the amount of gas outflow increases, the sealing capability is increased by a strong pressing force based on the internal pressure, and the outflow of gas can be suppressed.

In addition, when the internal pressure is low and the amount of gas outflow does not increase, the pressing force based on the internal pressure becomes weak.
Therefore, unlike the state in which a strong pressing force is always applied to the sealing means regardless of the internal pressure as in the case where the biasing force by the biasing means is increased, in the present invention, the strong pressing force is applied to the sealing means when the internal pressure is high. A weak pressing force is applied when the internal pressure is low, but wear and surface roughness of the sliding portion of the sealing means are suppressed as compared with a case where a strong pressing force is always applied. .
Therefore, it is possible to realize both prevention of gas outflow and prevention of wear and surface roughness of the sealing means.

  The throttle valve device according to a second aspect is the invention according to the first aspect, wherein the accommodating portion is provided with a space for introducing the gas in the pipe line through the communication passage. It is characterized by being.

  In the second aspect of the present invention, when the internal pressure on the upstream side of the pipe line is increased, the pressure in the space of the housing portion is increased, and the valve shaft can be reliably pressed.

  According to the present invention, in the throttle valve device that adjusts the gas flow rate, it is possible to prevent the exhaust gas from leaking from the bearing portion of the valve shaft and to suppress wear of the seal structure portion that prevents the exhaust gas from leaking. it can.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a sectional view showing an exhaust valve as a throttle valve device according to an embodiment of the present invention.
The exhaust valve of the present embodiment is different from the conventional exhaust valve in the structure of the bearing housing portion in a sealed state, but the basic structure of the other portions is the conventional one shown in FIG. 3, FIG. 4 and FIG. This is the same as the exhaust valve. Therefore, the same components as those of the conventional exhaust valve are denoted by the same reference numerals as those of the exhaust valve shown in FIGS. 3, 4 and 5, and the description thereof is omitted.

As shown in FIG. 1, in the exhaust valve 1a of this example, one bearing 7 that rotatably supports the valve shaft 4 is covered with a bottomed cylindrical bearing housing 51 in the same manner as in the prior art. The structure is hermetically sealed with respect to the outside of the valve housing 2 that is a part of the path.
The other bearing 8 that rotatably supports the valve shaft 4 is covered with a substantially cylindrical bearing housing with both ends open, and is not sealed, but has a seal structure similar to the conventional one. This prevents the exhaust gas from leaking out.

  As shown in FIG. 5, the seal structure is a seal sandwiched between a flange 4 a of the valve shaft 4 and a bearing 8 that rotatably supports one axial end of the valve shaft 4. The ring (seal member) 17 is pressed against the bearing 8 by the urging force of the spring 16 as the urging means, that is, gas pressure is prevented by acting between the seal ring and the bearing. To do. That is, the portion where the end surface 17a of the seal ring 17 and the end surface 8a of the bearing 8 are in contact with each other serves as a seal surface, and the exhaust gas flowing through the exhaust passage 3 supports the protruding side of the valve shaft 4 inside the bearing 8. Therefore, leakage from the outside of the valve housing 2 is prevented.

In this example, the bottomed cylindrical bearing housing 51 is not cylindrical, but bulges toward the upstream side of the exhaust gas flowing along the axial direction of the valve housing 2.
In the bearing housing 51, the communication path 21 is formed on the upstream side of the bearing 8. Further, a space 22 is formed as a gap between the inner surface of the bottom portion (upper end portion in FIG. 1) of the bearing housing 51 and the end surface facing the outside of the pipe line of the bearing 8.
Further, the end surface of the end portion on the bearing 8 side of the valve shaft 4 supported by the bearing 8 with respect to the space 22 is exposed (facing state). That is, the end of the bearing 8 facing the outside of the pipe line is not closed by a cap or the like, and the end face of the valve shaft 4 is visible from the opening of the bearing 8.

The communication path 21 and the space 22 are in communication with each other.
Further, the communication passage 21 formed on the upstream side of the bearing 8 is open toward the space in the valve housing 2 where the exhaust gas flows. Therefore, the communication path 21 communicates with the upstream side of the axis of the valve shaft 4 that rotates the valve body 10 of the pipe line (valve housing 2) through which the exhaust gas flows.
Further, as in the prior art, the bearing 8 is supported by the bearing housing 51 by being in contact with the outer peripheral surface of the bearing 8 over the entire inner peripheral surface of the bearing housing 51. First, in the bearing housing 51, a fixing member that fixes the bearing 8 to the bearing housing 51 in contact with the surface facing the upstream side of the flow of exhaust gas on the outer peripheral surface of the bearing 8 (the surface facing the communication path 21). 31 is provided.

  An inner portion of a portion formed by the fixing member 31 and a portion for fixing the bearing 8 to the fixing member 31 of the bearing housing 51 is an accommodating portion 32 for accommodating the bearing 8. That is, the portion including the space 22 is the accommodating portion 32 except for the communication path 21 in the bearing housing 51. The valve housing 2 is opened to a portion on the upstream side of the flow of the exhaust gas from the axial center of the valve shaft 4 which is a passage (flow path) of the exhaust gas through which the exhaust gas passes, and one end of the bearing 8 The communication passage 21 that communicates with the space 22 facing the portion includes an accommodation portion 32 in which one end portion of the valve shaft 4 supported by the one bearing 8 is accommodated, and the accommodation portion 32 and a part of the pipe line. The upstream side of the exhaust gas flow (upstream side of the valve body 10) communicates with the axis of the valve shaft 4 of the valve housing 2. The communication path 21 including the space 22 may be used, and a part of the space serving as the communication path 21 may be present in the accommodating portion 32.

  Here, in the exhaust valve 1a of this embodiment, as will be described later, the internal pressure upstream of the valve body 10 of the pipe line that is the exhaust pipe causes the valve body 10 to reduce the exhaust gas flow rate in the pipe line. When lifted by the operation, the valve shaft 4 acts so as to press in the same direction as the biasing direction of the spring 16, so that the biasing force of the spring 16 is pressed against the seal ring 17 by the biasing force of the spring 16. It is set lower than the conventional case. That is, the spring 16 having a lower urging force than that of the prior art is used.

  Further, when the exhaust valve 1a having such a configuration is operated, the exhaust body 1 of the exhaust valve 1a is in an open state, so that the exhaust pipe can be exhausted even when exhaust gas flows through the exhaust pipe (pipe). When the internal pressure of the seal ring 17 is not so high and is close to atmospheric pressure (but higher than atmospheric pressure), the end surface 17a of the seal ring 17 is mainly applied to the end surface 8a of the bearing 8 by the biasing force of the spring 16. It is in a pressed state.

In this case, although the biasing force of the spring 16 is weaker than before, the pressure in the exhaust pipe is not high, so the amount of exhaust gas leakage from the bearing 8 portion is small, and the exhaust gas outflow from the bearing 8 portion is the same as in the past. rare.
When the valve body 20 is rotationally driven in this state, since the biasing force of the spring is weaker than before, the pressing force of the seal ring 17 to the bearing 8 is low, and wear and surface roughness of the contact portion are prevented.

  When the valve body 10 is rotated around the valve shaft 4 so that the valve body 10 blocks the flow of exhaust gas in the exhaust pipe, the internal pressure on the upstream side of the valve body 10 in the exhaust pipe increases. In this case, the space 22 in which at least the end surface of one end of the valve shaft 4 of the accommodating portion 32 is exposed by the communication passage 33 (when the end surface of the valve shaft 4 is in the bearing 8, the end surface in the bearing 8 is Up to the upstream side of the valve body 10 of the exhaust pipe (the pipe line as the valve housing 2) (upstream side of the axis of the valve shaft 4). The internal pressure in the space 22 also increases.

As a result, the other end portion of the valve shaft 4 is in the atmospheric pressure outside the pipe line, and therefore, the pressing force generated by the increase in the internal pressure of the space 22 of the accommodating portion 32 causes the one end to the other end. It will be pressed in the direction toward the part.
Therefore, the urging force by the spring 16 and the pressing force based on the increase of the internal pressure in the exhaust pipe act on the seal ring 17 portion, and a stronger pressing force than the case of the spring 16 alone acts.

Further, since the pressing force based on the increase in the internal pressure becomes stronger as the internal pressure increases, when the internal pressure increases and the amount of exhaust gas flowing out from the bearing 8 tends to increase, the pressing force acting on the seal ring 17 portion is increased. The pressure becomes stronger and the sealing ability is improved, thereby suppressing an increase in the outflow amount of exhaust gas.
That is, when the internal pressure increases and the outflow amount of the exhaust gas tends to increase, the sealing ability is improved and the outflow amount of the exhaust gas is suppressed. Therefore, even if the internal pressure increases, the increase in the outflow amount of the exhaust gas is prevented.

  Here, when the internal pressure of the exhaust pipe rises and the pressing force to the seal ring 17 increases, there is a risk that wear due to the rotation of the valve shaft 4 may increase, but when the internal pressure is low as described above, Since the pressure is weak and wear is reduced, for example, the internal pressure decreases as the urging force of the spring 16 is increased so that the increase in the outflow amount of exhaust gas can be suppressed even when the internal pressure is high. However, a strong pressing force is not maintained. Therefore, by making the pressing force variable according to the internal pressure, wear can be reduced as compared with the case where the urging force of the spring 16 is increased.

  That is, since the pressing force to the seal ring 17 portion changes depending on the internal pressure of the exhaust pipe, it is possible to efficiently reduce the outflow amount of the exhaust gas while suppressing wear.

  Here, in the graph shown in FIG. 2, (a) shows an example of the internal pressure in the exhaust pipe, and the plate-like valve body 10 is orthogonal to the axial direction of the pipe body, that is, the fully closed state. The internal pressure corresponding to the fully opened state (in fact, there is a gap and is not completely closed) is shown. The internal pressure is an upstream portion of the exhaust gas from the valve body 10.

  FIG. 2B shows the pressing force acting on the valve shaft 4 corresponding to the internal pressure. In the exhaust valve 1a of this example, for example, the urging force of the spring 16 is half that of the conventional exhaust valve 1 of the same standard. In the graph shown in FIG. 2B, the pressing force based on the conventional spring 16 is shown by a broken line.

  When the internal pressure rises, a pressing force acts on the valve shaft 4, and in the fully closed state, a higher pressing force acts on the seal ring 17 portion than before, and a sufficient sealing ability can be obtained.

In other words, in the conventional configuration, in order to prevent exhaust gas leakage when the internal pressure is high, when the urging force of the spring 16 is further increased from the current level, a strong pressing force is always applied regardless of the internal pressure of the exhaust pipe. As a result, the wear becomes intense, and there is a possibility that the wear becomes excessively large with respect to the effect of preventing exhaust gas leakage.
On the other hand, according to the exhaust valve 1a of this example, by applying a pressing force according to the internal pressure to the seal structure portion, it is possible to reliably reduce the amount of exhaust gas leakage while suppressing wear.

The throttle valve device according to the present invention is not only a valve provided in the exhaust pipe, but also has a high internal pressure and a seal structure for a valve shaft bearing that rotates the valve body. It is applicable to the valve which is performing.
In an intake pipe of a normal natural intake engine, air is sucked from the downstream side, and the internal pressure is a negative pressure, so the present invention cannot be applied. For example, the upstream side of the valve of the intake pipe If a turbocharger such as a mechanical supercharger or an exhaust turbine supercharger is provided, the valve portion provided in the intake pipe is at a high pressure. The throttle valve device of the present invention can be applied to the intake pipe side as long as it is configured to press the seal portion by urging with a spring.

It is sectional drawing which shows the exhaust valve as a throttle valve apparatus of embodiment of this invention. It is a graph for demonstrating the pressing force which acts on the valve shaft of the said exhaust valve. It is a top view which shows the conventional exhaust valve. FIG. 4 is a sectional view taken along line AA in FIG. 3. FIG. 5 is an enlarged view of a portion surrounded by a circle B in FIG. 4.

Explanation of symbols

1 Exhaust valve 2 Valve housing (pipe)
4 valve shaft 4a flange 51 bearing housing 7 bearing 8 bearing 8a end face 10 in contact with bearing seal ring 10 valve element 16 spring (biasing means)
17 Seal ring (seal member)
17a End surface 21 in contact with seal ring bearing 22 Communication path 22 Space 32 Housing portion

Claims (2)

A conduit through which gas flows;
A valve body for adjusting the flow rate of the gas flowing through the pipe line by changing the rotation angle;
A valve shaft connected to the valve body and rotating the valve body;
A bearing that rotatably supports the valve shaft;
Provided between the pipe line and the bearing;
A seal member for preventing gas outflow from the bearing;
A throttle valve device comprising an urging means for applying a pressing force between the seal member and the bearing,
A throttle valve comprising: a housing portion that houses one end of the valve shaft; and a communication passage that communicates the housing portion with the upstream side of the valve body in the pipe. apparatus. The throttle valve device according to claim 1, wherein a space for introducing the gas in the pipe line through the communication path is provided in the housing portion.

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