JP2006029469A - Air flow rate control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the failure of a rotary valve 3 and the valve lock, and to make valve leakage amount in an idling operation approximately zero. <P>SOLUTION: When an engine is stopped, the rotary valve 3 is moved to a valve opening side in the radial direction of a rotor shaft 2 by energizing force of a spring acting on a bearing part 23 of the rotary valve 3, thus a clearance between a valve housing 1 and the rotary valve 3 is widened to the maximum, and foreign matters are prevented from being caught in the clearance during engine stop. In the idling operation, the suction force in the arrow direction in a figure, generated when a suction pipe negative pressure is higher than a specific value, is stronger than the energizing force of the spring, thus the rotary valve 3 is moved to a valve closing side in the radial direction of the rotor shaft 2 by the suction force in the arrow direction in the figure, acting on a seat part 21 of the rotary valve 3, the clearance is narrowed to the minimum, and the valve leakage amount in the idling operation becomes approximately zero. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air flow rate control valve that adjusts the flow rate of air passing through an air passage port of a housing, and in particular, intake air flowing in an intake passage, a bypass passage, or an exhaust gas recirculation passage communicating with a combustion chamber of an internal combustion engine. The air flow control valve for adjusting the flow rate of

[Conventional technology]
Conventionally, in an intake control device for an internal combustion engine, when the throttle valve is fully closed, if the clearance between the outer peripheral end surface of the throttle valve and the throttle bore wall surface of the throttle body is small, the unburned gas that flows backward from the engine The foreign matter contained in the deposit adheres to the throttle valve and accumulates as deposits (deposits), and the foreign matter that adheres to the throttle valve and solidifies is formed between the outer peripheral end surface of the throttle valve and the throttle bore wall surface of the throttle body. Intrusion into the clearance between them causes a biting phenomenon (valve stick), which causes malfunction of the throttle valve and valve block. The intake air sucked into the combustion chamber of the internal combustion engine has almost no foreign matter removed by the air filter in the air cleaner, but is not completely removed, and the foreign matter having a small particle diameter that could not be removed by the air filter. May intrude into the clearance between the outer peripheral end surface portion of the throttle valve and the throttle bore wall surface of the throttle body, and a biting phenomenon (valve stick) may occur.

  In addition, high-viscosity foreign substances (adhesive substances such as deposits, sludge, carbon, etc. contained in unburned gas) striking the throttle valve straddle the outer peripheral end surface of the throttle valve and the throttle bore wall surface of the throttle body. If accumulated, it becomes difficult to peel the throttle valve from the wall surface of the throttle bore during operation of the internal combustion engine, resulting in malfunction of the throttle valve and valve block. Such a symptom applies not only to the throttle valve of the intake control device for the internal combustion engine, but also to the valve of the exhaust gas recirculation control valve of the exhaust gas recirculation device and the valve of the idle rotation speed control valve of the idle rotation speed control device. To happen.

  Therefore, for the purpose of preventing malfunction of the rotary valve 101 and biting of foreign matter, as shown in FIG. 4, the outer peripheral wall surface 102 of the rotary valve 101 and the housing 103 are changed between when the engine is running and when the engine is stopped. There has been proposed an idle rotational speed control valve in which a clearance formed between the housing wall 104 and the housing wall 104 is variable (see, for example, Patent Document 1). This is because the rotary valve 101 can be moved in the axial direction of the rotor shaft 107 by the axial gap of the ball bearings 105 and 106, and by utilizing the relationship between the magnet force and the presence or absence of intake pipe negative pressure, By making the minute gap (clearance) formed between the outer peripheral side wall surface 102 of the rotary valve 101 and the housing wall surface 104 of the housing 103 variable when the engine is operating and when the engine is stopped, the rotary valve 101 can be changed. It prevents malfunction and foreign matter biting. Note that the outer peripheral side wall surface 102 of the rotary valve 101 and the housing wall surface 104 of the housing 103 are opposed to each other with a clearance by a screw 109 provided on one end side in the axial direction of the rotor shaft 107, that is, the rotary valve 101. The outer peripheral side wall surface 102 and the housing wall surface 104 of the housing 103 are set so as not to directly contact each other.

  In recent years, there has been a demand for reducing fuel consumption in internal combustion engines. One technique for meeting this requirement is a reduction in idle rotation speed. In order to achieve this reduction in idle rotation speed, it is necessary to reduce the amount of leaked air (also referred to as valve leakage) when the throttle valve of the intake throttle device for an internal combustion engine that controls the amount of intake air is fully closed. is there. Therefore, for the purpose of reducing the amount of valve leakage when the throttle valve 111 is fully closed, as shown in FIG. 5, when the throttle valve 111 is fully closed, the mounting portion 112 and the clamping member 113 on the outer peripheral side of the throttle valve 111 are used. In the meantime, an intake throttle device for an internal combustion engine is proposed in which a seal member 116 made of a resin material softer than the throttle bore wall surface 115 of the throttle body 114 is directly brought into contact with the throttle bore wall surface 115 for sealing. (For example, refer to Patent Document 2).

[Conventional technical problems]
However, in the idle rotational speed control valve described in Patent Document 1, since the rotary valve 101 can move only a little as much as the axial gap between the ball bearings 105 and 106, a highly viscous foreign material (adhesive substance) flying in is present. When an attempt is made to operate the rotary valve 101 when it enters the clearance formed between the outer peripheral side wall surface 102 of the rotary valve 101 and the housing wall surface 104 of the housing 103, the adhesive substance is peeled off from the rotary valve 101. This causes a problem that the rotary valve 101 malfunctions and a valve block occurs. In addition, foreign matter such as sludge having a slightly larger particle size is caught between the outer peripheral side wall surface 102 of the rotary valve 101 and the housing wall surface 104 of the housing 103, so that a biting phenomenon (valve stick) occurs. As a result, problems such as malfunction of the throttle valve and occurrence of a valve block occur. Further, since the outer peripheral wall surface 102 of the rotary valve 101 and the housing wall surface 104 of the housing 103 are set so as not to directly contact each other, there is a problem that the amount of valve leakage during idle operation is large and fuel consumption is deteriorated. Occurs.

In the intake throttle device for an internal combustion engine described in Patent Document 2, the seal member 116 having a large linear expansion coefficient is generally formed long in the radial direction (radial direction) of the throttle valve 111 and the throttle shaft 117. The difference between the linear expansion coefficients of the throttle valve 111 and the throttle body 114 is increased, and the amount of valve leakage that has been reduced is increased, resulting in a deterioration in fuel consumption. Further, since a low friction plastic material such as ethylene tetrafluoride resin is formed on the throttle valve 111 side, the low friction plastic material is removed from the throttle valve 111 due to an operating impact when the throttle valve 111 is rotated. It is easy to cause a problem that the effect of reducing the sliding resistance by the low friction plastic material is lowered.
Japanese Patent Laid-Open No. 11-013603 (page 1-8, FIGS. 1 to 13) Japanese Patent Laid-Open No. 11-101137 (page 1-9, FIGS. 1 to 13)

  The object of the present invention is to prevent malfunction of the valve body and valve lock by preventing foreign matter biting phenomenon (valve stick) when the valve body is in the closed position where the opening area of the air passage opening is minimized. An object of the present invention is to provide an air flow rate control valve that can be used. It is another object of the present invention to provide an air flow rate control valve that can substantially reduce the amount of valve leakage during idling of an internal combustion engine.

  According to the first aspect of the present invention, when the valve body is in the valve closing position where the opening area of the air passage opening is minimized, the seal wall portion of the housing and the valve body are arranged to face each other with a predetermined clearance. It is configured to be. And the minute clearance of the radial direction substantially orthogonal to the thrust direction of a fitting part is formed between the fitting part of a drive shaft, and the bearing part of a valve body. And by installing a valve body urging means for urging the valve body on the valve opening side in the radial direction of the fitting portion, when the valve body is in the closed position that minimizes the opening area of the air passage port, The clearance formed between the seal wall portion of the housing and the valve body is increased by the biasing force of the valve body biasing means. Accordingly, since the clearance formed between the seal wall portion of the housing and the valve body is large, it is difficult for foreign matter to bite into the clearance. Therefore, a foreign matter biting phenomenon (valve stick) can be prevented, so that malfunction of the valve element and valve lock (valve block) can be avoided.

  According to the second aspect of the present invention, the housing is assembled to the intake pipe that forms the intake passage communicating with the combustion chamber of the internal combustion engine. An air passage that bypasses the throttle valve that opens and closes the intake passage is formed inside the housing. Here, during idle operation of the internal combustion engine, the air pressure in the intake pipe, in particular, the air pressure in the intake pipe downstream of the throttle valve becomes a high negative pressure of a predetermined value or more, and during normal operation of the internal combustion engine, Air pressure, particularly the air pressure in the intake pipe on the downstream side of the throttle valve becomes a low negative pressure or a medium negative pressure below a predetermined value.

  According to the third aspect of the present invention, the urging force of the valve body urging means is the radial closing valve that acts on the valve body when the air pressure in the intake pipe is a low negative pressure or a medium negative pressure less than a predetermined value. Set to be larger than the suction force on the valve closing side in the radial direction acting on the valve element when the air pressure in the intake pipe is high negative pressure higher than a predetermined value. As a result, when the air pressure in the intake pipe is a high negative pressure higher than a predetermined value, the suction force on the valve closing side in the radial direction acts on the valve body against the biasing force of the valve body biasing means. The body abuts against the seal wall of the housing. As a result, the amount of valve leakage when the air pressure in the intake pipe during the idling operation is a high negative pressure exceeding a predetermined value can be made substantially zero. Therefore, deterioration of fuel consumption can be prevented.

  According to the fourth aspect of the present invention, by forming a low friction plastic material on the seal wall portion of the housing for reducing the adhesion force of the foreign material and increasing the peeling force of the foreign material, the foreign material is Since it becomes difficult to adhere to the seal wall portion, it is difficult for foreign matter to enter the clearance formed between the seal wall portion of the housing and the valve body. Therefore, for example, when the valve body is in the closed position where the opening area of the air passage opening is minimized, such as when the operation of the internal combustion engine is stopped, a foreign matter biting phenomenon (valve stick) can be prevented. Malfunction and valve lock (valve block) can be avoided.

  According to the fifth aspect of the present invention, the gap dimension of the minute radial gap is set so that the valve body comes into front contact with the low friction plastic material when the air pressure in the intake pipe is a high negative pressure of a predetermined value or more. Thus, the amount of valve leakage at the time of high negative pressure where the air pressure in the intake pipe is higher than a predetermined value, such as during idling of the internal combustion engine, can be made substantially zero. Therefore, deterioration of fuel consumption can be prevented. Also, by forming a low-friction plastic material on the seal wall of the housing to reduce the adhesion of foreign matter, it becomes difficult to remove the low-friction plastic material due to the operating impact when the valve element is driven. The effect of reducing sliding resistance by the plastic material will not decrease.

  According to the sixth aspect of the present invention, by forming the low friction plastic material thinly below a predetermined value, it is possible to minimize the influence on valve leakage caused by the difference in linear expansion coefficient. According to the seventh aspect of the present invention, by forming the low friction plastic material thicker than the foreign material, even if the foreign material is caught between the seal wall portion of the housing and the valve body, the rotation operation of the valve body is performed. By scraping off the low-friction plastic material, the foreign matter is removed from between the seal wall portion of the housing and the valve body, so that malfunction of the valve body and valve lock can be avoided. According to the eighth aspect of the present invention, a rotary valve may be used as the valve body. The rotary valve is supported so as to be slidable in the radial direction with respect to the drive shaft and not to rotate relative to the drive shaft, and the rotation angle is changed by rotating integrally with the drive shaft. Since the opening area of the air passage opening of the housing changes, the flow rate of air passing through the air passage opening can be adjusted.

  The best mode for carrying out the present invention is that when the valve body is in the closed position where the opening area of the air passage opening is minimized, that is, when the air pressure in the intake pipe is low, such as when the engine is stopped In order to avoid malfunction of the valve body and valve lock (valve block) at negative pressure, the clearance formed between the seal wall of the housing and the valve body is increased, and the foreign matter biting phenomenon ( Realized by preventing valve stick). Also, when the valve body is in the closed position that minimizes the opening area of the air passage port, that is, when the air pressure in the intake pipe is high negative pressure exceeding a predetermined value, such as during idle operation, the valve leakage amount is substantially zero. This is achieved by setting the urging force of the valve element urging means so that the valve element comes into direct contact with the seal wall of the housing when the air pressure in the intake pipe exceeds a predetermined value. did.

[Configuration of Example 1]
FIGS. 1 to 3 (a) show a first embodiment of the present invention, and FIG. 1 is a view showing a main structure of an air flow rate control valve.

  The air flow rate control valve (intake air amount control valve) of this embodiment is accommodated in an engine intake pipe, in particular, a throttle body (not shown) so as to be freely opened and closed during an idling operation of an internal combustion engine (hereinafter referred to as an engine). It is used as an idle speed control valve (idle speed control valve: ISCV) for controlling the amount of intake air that bypasses a throttle valve (not shown). The air flow control valve includes a valve housing 1 mounted on an outer wall portion of a throttle body (not shown), a rotor shaft (drive shaft) 2 rotatably accommodated in the valve housing 1, and the rotor. A rotary valve (valve element) 3 fitted to the outer periphery of the shaft 2, an actuator (not shown) for rotationally driving the rotary valve 3, and a spring (valve element biasing) that urges the rotary valve 3 in the valve opening direction. (Means) 4.

  The valve housing 1 is made of, for example, a die-cast product made of an aluminum alloy containing aluminum as a main component, and an outer wall of a throttle body that forms an intake passage for sucking intake air into the combustion chamber of each cylinder of the engine. Connected to the department. The valve housing 1 has a substantially circular cylindrical wall 6 that forms a bypass passage 5 therein. An opening (air inlet) 11 for allowing intake air to flow into the bypass passage 5 from the intake passage on the upstream side of the throttle valve is formed in the pipe joint 7 on the upper end side of the cylindrical wall portion 6 in the figure. ing.

  Further, an opening (air outlet: hereinafter referred to as air passage) through which the intake air flows out from the bypass passage 5 into the pipe joint 8 on the right end side in the figure of the cylindrical wall portion 6 into the intake passage downstream of the throttle valve. 12) is formed. The air passage port 12 is a rectangular valve hole. Further, the valve housing 1 has a rotary valve 3 in a closed position where the opening area of the air passage 12 is minimized, that is, in a closed position where the amount of intake air flowing through the bypass passage 5 is minimized (the rotary valve 3 A seal wall (valve seat) 9 is provided on which the rotary valve 3 is slidably contacted with a predetermined clearance when the valve is closed. The seal wall portion 9 is formed in a frame shape or a rectangular ring shape so as to surround the air passage port 12.

  The rotor shaft 2 is made of a metal material such as stainless steel, for example, and has a fitting section 19 having a rectangular cross section to be fitted to the rotary valve 3. At both ends in the axial direction from the fitting portion 19, there are provided bearing sliding portions (not shown) having a circular cross section that are rotatably supported by roller bearings (not shown). One end portion of the rotor shaft 2 in the axial direction is drivingly connected to the actuator. Here, the actuator is a motor actuator (for example, a drive motor such as a stepping motor) that is held and fixed to the valve housing 1, and is a field that can be energized and controlled by an unillustrated engine control unit (engine control device: hereinafter referred to as ECU). A coil, a magnetic path forming member (such as a yoke housing and a stator core) magnetized by the magnetomotive force of the field coil, and a rotor magnet integrally provided at one end of the rotor shaft 2 in the axial direction. Z)). The field coil is wound around the outer periphery of the coil bobbin and electrically connected to a terminal molded in the connector.

  The rotary valve 3 is a rotary valve made of a metal material such as stainless steel and swinging about the rotation center axis of the rotor shaft 2. The opening area of the air passage port 12 according to the rotation angle (valve angle). Is changed, the amount of intake air flowing through the bypass passage 5 as an air passage, that is, the flow rate of air passing through the air passage port 12 is controlled. The rotary valve 3 is integrally formed with an arc-shaped seat portion 21 which is slidably contacted with a housing wall surface of the seal wall portion 9 of the valve housing 1 or opposed to each other with a predetermined clearance, and from both ends of the seat portion 21. A pair of formed valve holding portions 22 is provided. The pair of valve holding portions 22 are integrally provided with a bearing portion 23 which forms a minute radial clearance (S) substantially perpendicular to the thrust direction of the rotor shaft 2 between the pair of valve holding portions 22. . The bearing portion 23 is provided with a rectangular fitting hole 24 that fits into the fitting portion 19 of the rotor shaft 2.

  In this embodiment, in order to define the rotor shaft 2 and the rotary valve 3 to have a constant relative angle (assembly angle), the rotor shaft 2 and the rotary valve 3 are further prevented from rotating relative to each other. For this purpose, two-sided width portions 26 and 27 are formed on the outer periphery of the fitting portion 19 of the rotor shaft 2 and the inner periphery of the fitting hole 24 of the bearing portion 23 of the rotary valve 3, respectively. The two-surface width portions 26 and 27 are the valve closing positions where the rotary valve 3 minimizes the opening area of the air passage port 12, that is, when the rotary valve 3 is closed, the rotary valve 3 is a fitting portion of the rotor shaft 2. 19 is provided at a position where it can move in the horizontal direction in the figure.

  The spring 4 is formed in an elliptical shape, and the housing of the seal wall portion 9 of the valve housing 1 when the rotary valve 3 is in the closed position where the opening area of the air passage 12 is minimized, that is, when the rotary valve 3 is closed. In order to increase the clearance formed between the wall surface and the opposing wall surface of the seat portion 21 of the rotary valve 3, the bearing portion 23 of the rotary valve 3 is moved in the thrust direction (axial direction) of the fitting portion 19 of the rotor shaft 2. It is a valve body urging means that urges the valve in the radial direction (radial direction) substantially perpendicular to the valve opening side (left direction in FIG. 2A).

  One side of the inner diameter of the spring 4 is locked or held by the fitting portion 19 of the rotor shaft 2, and the other side of the inner diameter of the spring 4 is the bearing portion of the rotary valve 3. 23 is locked or held. Here, the urging force (spring load, spring force) of the spring 4 of this embodiment is an intake air corresponding to the air pressure in the engine intake pipe when the engine is stopped (when the engine is stopped) or during the normal operation of the engine. When the pipe negative pressure (P0 or P2) is a low negative pressure or a medium negative pressure lower than a predetermined value, the radial valve closing side acting on the opposing wall surface of the seat portion 21 of the rotary valve 3 (FIG. 2A or FIG. It is set to a value larger than the suction force in the direction of the arrow shown in FIG. 3 (a), and when the intake pipe negative pressure (P1) is a high negative pressure equal to or higher than a predetermined value as in idle operation, It is set to a value smaller than the suction force on the valve closing side in the radial direction (the illustrated arrow direction shown in FIG. 2B) acting on the opposing wall surface of the seat portion 21 of the valve 3.

[Operation of Example 1]
Next, the operation of the air flow control valve of this embodiment will be briefly described with reference to FIGS. 1 to 3A. Here, FIG. 2A is a diagram showing the valve position of the rotary valve when the engine is stopped, and FIG. 2B is a diagram showing the valve position of the rotary valve when the engine is idling. a) is a diagram showing the valve position of the rotary valve during normal operation of the engine.

A) When the engine is stopped Since it is not necessary to control the idle rotation speed when the engine is stopped, the energization of the field coil of the actuator from the ECU is also stopped. Thereby, as shown in FIG. 1 and FIG. 2A, the rotary valve 3 has a clearance between the facing wall surface of the seat portion 21 and the housing wall surface of the seal wall portion 9 of the valve housing 1. Stops at the opposite position. At this time, the air pressure in the engine intake pipe is a pressure equivalent to atmospheric pressure (for example, the intake pipe negative pressure (P0) downstream of the throttle valve is P0 = 0 mmHg).

  Further, when the engine is stopped, the spring 4 in the leftward direction acting on the bearing portion 23 of the rotary valve 3 rather than the suction force in the direction of the illustrated arrow which is generated when the intake pipe negative pressure (P0) is a low negative pressure lower than a predetermined value. As shown in FIG. 2A, the urging force of the spring 4 in the leftward direction acting on the bearing portion 23 of the rotary valve 3 causes the rotary valve 3 to move to the rotor shaft 2 as shown in FIG. The fitting part 19 moves to the valve opening side in the radial direction (the left direction in the figure). Thereby, a minute radial gap (S) is formed between the illustrated left side surface of the fitting portion 19 of the rotor shaft 2 and the illustrated left hole wall surface of the fitting hole 24 of the rotary valve 3. Since the clearance between the housing wall surface of the seal wall portion 9 and the opposing wall surface of the seat portion 21 of the rotary valve 3 is the widest, it is difficult for foreign matter to get caught in the clearance while the engine is stopped.

B) During idle operation During idle operation of the engine, the throttle valve is returned to the fully closed position, and the fully closed clearance between the outer peripheral end surface of the throttle valve and the throttle bore wall surface of the throttle body is minimized. When the intake valve of the engine opens, the exhaust valve closes, and the piston moves downward from the top dead center to the bottom dead center, negative pressure is generated in the combustion chamber of the engine cylinder. As described above, when negative pressure is generated in the combustion chamber of the cylinder of the engine, the intake pipe negative pressure (P1) downstream of the throttle valve becomes a high negative pressure equal to or higher than a predetermined value.

  Further, during idle operation, the direction of the arrow shown in the figure is generated when the intake pipe negative pressure (P1) is higher than a predetermined value than the urging force of the spring 4 in the left direction acting on the bearing portion 23 of the rotary valve 3. As shown in FIG. 2B, the rotary valve 3 is attached to the rotor shaft 2 by the suction force in the direction indicated by the arrow acting on the opposing wall surface of the seat portion 21 of the rotary valve 3 as shown in FIG. It moves to the valve closing side (right direction in the figure) of the fitting portion 19 in the radial direction. As a result, the opposing wall surface of the seat portion 21 of the rotary valve 3 comes into contact (sitting) with the housing wall surface of the seal wall portion 9 of the valve housing 1, so that the housing wall surface of the seal wall portion 9 of the valve housing 1 and the rotary valve 3 Since the clearance between the opposing wall surface of the seat portion 21 is the narrowest, the amount of valve leakage during idle operation is substantially zero.

  Here, the opening area of the air passage 12 may be changed according to the engine load during the idling operation. In this case, when a drive current is applied from the ECU to the field coil of the actuator and the field coil is energized, magnetic path forming members such as the yoke housing and the stator core are magnetized to generate an attractive force. Since the rotor magnet holding the magnet on the outer periphery is rotated by the attractive force corresponding to the drive current value applied to the field coil, the rotor shaft 2 rotates integrally with the rotor magnet. The rotary valve 3 rotates about the rotation center axis of the rotor shaft 2 as the rotor shaft 2 rotates, and the rotary valve 3 rotates from the position facing the housing wall surface of the seal wall portion 9 of the valve housing 1 with a clearance. As the seat portion 21 of the valve 3 rotates in the rotation direction, the opening area of the air passage port 12 provided on the downstream side of the bypass passage 5 is slightly opened.

  As described above, the air flow rate control valve changes the opening area of the air passage 12 and variably controls the intake air amount supplied to the combustion chamber of each cylinder of the engine via the bypass passage 5. During idle operation, that is, when the throttle valve is fully closed, the idle rotation speed is controlled according to the engine load and the engine warm-up state. For example, even when the engine load is increased by operating an air conditioner, the air flow control valve increases the opening area of the air passage port 12 provided on the downstream side of the bypass passage 5 so that the combustion of each cylinder of the engine is performed. The amount of intake air supplied into the room can be increased, and engine stall can be prevented.

C) During normal operation of the engine During normal operation of the engine, such as when the vehicle is running, the throttle valve has an intermediate throttle opening between the fully closed position and the fully open position, and the intake pipe negative pressure downstream of the throttle valve. (P2) is a low negative pressure or a medium negative pressure less than a predetermined value. Further, during normal operation of the engine, the suction force in the direction of the arrow shown in the drawing acts when the intake pipe negative pressure (P2) is a low negative pressure or a medium negative pressure lower than a predetermined value, and acts on the bearing portion 23 of the rotary valve 3. Since the urging force of the spring 4 in the upper left direction in the figure is superior, as shown in FIG. 3A, the urging force of the spring 4 in the upper left direction in the figure acting on the bearing portion 23 of the rotary valve 3 is used. However, it moves to the valve-opening side (upper left direction in the figure) of the fitting portion 19 of the rotor shaft 2 in the radial direction. Thus, a minute radial gap (S) is formed between the upper left side surface of the fitting portion 19 of the rotor shaft 2 and the upper left hole wall surface of the fitting hole 24 of the rotary valve 3, so that the valve housing 1 Since the clearance between the housing wall surface of the seal wall portion 9 and the opposing wall surface of the seat portion 21 of the rotary valve 3 is the widest, it is difficult for foreign matter to get caught in the clearance during normal operation of the engine.

  At this time, the rotary valve 3 rotates about the rotation axis of the rotor shaft 2 as described above by applying a drive current from the ECU to the field coil of the actuator and energizing the field coil. Thus, the air provided on the downstream side of the bypass passage 5 by rotating the seat portion 21 of the rotary valve 3 in the rotational direction from a position facing the housing wall surface of the seal wall portion 9 of the valve housing 1 with a clearance therebetween. The opening area of the passage port 12 is opened. As described above, the air flow rate control valve changes the opening area of the air passage 12 and variably controls the intake air amount supplied to the combustion chamber of each cylinder of the engine via the bypass passage 5. During normal driving, that is, during vehicle travel, for example, the engine speed is controlled in accordance with the amount of depression of the accelerator pedal (accelerator operation amount, accelerator opening) or the rotation angle of the throttle valve (throttle opening).

[Effect of Example 1]
As described above, in the air flow control valve of the present embodiment, the intake pipe negative pressures (P0 and P2) at the time of low negative pressure or medium negative pressure when the engine is stopped and during normal operation of the engine are less than a predetermined value. Sometimes, the rotary valve 3 is in a closed position where the opening area of the air passage 12 is minimized, and the opposing wall surface of the seat portion 21 of the rotary valve 3 is separated by a predetermined clearance so that the seal wall portion 9 of the valve housing 1 is separated. Even when the housing is disposed opposite to the housing wall surface, the rotary valve 3 is engaged with the rotor shaft 2 by the urging force of the spring 4 in the leftward direction acting on the bearing portion 23 of the rotary valve 3. It moves to the valve opening side (the left direction in the drawing) of the radial direction of the part 19. As a result, the clearance between the housing wall surface of the seal wall portion 9 of the valve housing 1 and the opposing wall surface of the seat portion 21 of the rotary valve 3 becomes the widest, so that foreign matter is present in the clearance when the engine is stopped and during normal operation of the engine. It becomes difficult to bite.

  Further, as described above, since the clearance between the housing wall surface of the seal wall portion 9 of the valve housing 1 and the opposing wall surface of the seat portion 21 of the rotary valve 3 is the largest, the opposing wall surface of the seat portion 21 of the rotary valve 3 is Highly viscous foreign matter (adhesive substances such as deposits, sludge, carbon, etc. contained in unburned gas, exhaust gas or blow-by gas) flying from the combustion chamber side (or exhaust passage side) of the engine It is difficult to deposit over the housing wall surface of the wall portion 9 and the opposing wall surface of the seat portion 21 of the rotary valve 3. As a result, a foreign matter biting phenomenon (valve stick) can be prevented, and the adhesive substance can be easily peeled from the seat portion 21 of the rotary valve 3 when the rotary valve 3 is operated in the rotational direction. Therefore, malfunction of the rotary valve 3 and valve lock (valve block) can be avoided.

  Further, when the intake pipe negative pressure (P1) is a high negative pressure that is equal to or higher than a predetermined value, such as during idle operation, the intake pipe negative pressure is greater than the biasing force of the spring 4 in the left direction acting on the bearing portion 23 of the rotary valve 3. Since the suction force in the direction of the arrow shown in the figure when the pressure (P1) is a high negative pressure equal to or higher than a predetermined value is superior, the suction force in the direction of the arrow shown in the figure acting on the opposing wall surface of the seat portion 21 of the rotary valve 3 The valve 3 moves to the valve closing side in the radial direction of the fitting portion 19 of the rotor shaft 2 (right direction in the drawing). As a result, the clearance between the housing wall surface of the seal wall portion 9 of the valve housing 1 and the opposing wall surface of the seat portion 21 of the rotary valve 3 becomes the narrowest, so that the valve leakage amount during idle operation can be made substantially zero. it can. Therefore, deterioration of fuel consumption can be prevented.

[Features of Example 2]
FIG. 3B shows the second embodiment of the present invention, and is a view showing the valve position of the rotary valve when the engine is idling.

  In the air flow rate control valve of the present embodiment, as shown in FIG. 3B, the fluorine-based resin coat layer 10 is formed on the housing wall surface (surface) of the seal wall portion 9 of the valve housing 1. This fluorine-based resin coat layer 10 reduces the sticking force of highly viscous foreign matters (adhesive substances such as deposits, sludge, carbon, etc. contained in unburned gas) flying to the rotary valve 3 and the foreign matter peeling force. A low friction plastic material (plastic seal member) for increasing As the low friction plastic material, a fluorine resin (for example, tetrafluoroethylene resin: PTFE) is desirable. The fluorine-based resin coat layer 10 may be coated (coated) on the housing wall surface of the seal wall portion 9 of the valve housing 1 by baking the PTFE at a high temperature, or on the housing wall surface. May be sprayed using a spray can or a gun, or the PTFE may be applied to the housing wall surface using a cotton swab, or the PTFE may be applied to the housing wall surface using an adhesive (for example, an epoxy-based resin). You may adhere | attach using a normal temperature hardening two-pack type adhesive agent etc.).

  Here, the fluorine-based resin coat layer 10 of the present embodiment is formed on the housing wall surface of the seal wall portion 9 of the valve housing 1 as thin as possible. However, a thickness that can avoid foreign matters is desirable. Further, when the intake pipe negative pressure (P1) is a high negative pressure equal to or higher than a predetermined value, such as during idling of the engine, the housing wall surface of the seal wall portion 9 of the valve housing 1 and the opposing wall surface of the seat portion 21 of the rotary valve 3 The fitting portion 19 of the rotor shaft 2 and the bearing portion 23 of the rotary valve 3 are fitted so that the fluorine-based resin coat layer 10 comes into front contact with the seat portion 21 of the rotary valve 3 in a state where they are in direct contact with each other. The gap dimension of the radial minute gap (S) formed between the holes 24 is set.

  With the above configuration, the fluorine-based resin coat layer 10 is formed as thin as possible, so that it is possible to minimize the influence on valve leakage caused by the difference in linear expansion coefficient. Further, since the fluororesin coat layer 10 is formed thicker than the foreign matter, even if foreign matter is caught between the housing wall surface of the seal wall portion 9 of the valve housing 1 and the opposing wall surface of the seat portion 21 of the rotary valve 3. The foreign resin can be removed from between the housing wall surface of the seal wall portion 9 of the valve housing 1 and the opposing wall surface of the seat portion 21 of the rotary valve 3 by scraping off the fluorine-based resin coat layer 10 by the rotational operation of the rotary valve 3. Therefore, malfunction of the rotary valve 3 and valve lock (valve block) can be avoided.

  Further, a small radial gap (S) formed between the fitting portion 19 of the rotor shaft 2 and the fitting hole 24 of the bearing portion 23 of the rotary valve 3 has a predetermined value of the intake pipe negative pressure (P1). By setting the fluorine-based resin coat layer 10 to be in front contact with the seat portion 21 of the rotary valve 3 at the time of the above high negative pressure, the seat portion 21 of the rotary valve 3 minimizes the opening area of the air passage port 12. When the valve is closed, that is, when the intake pipe negative pressure (P1) is higher than a predetermined value, such as during idle operation, the valve leakage amount can be made substantially zero. Therefore, deterioration of fuel consumption can be prevented. Further, since the fluorine-based resin coat layer 10 for reducing the sticking force of the highly viscous foreign material flying to the rotary valve 3 is formed on the housing wall surface of the seal wall portion 9 of the valve housing 1, the rotary valve 3 Since the fluorine-based resin coat layer 10 is difficult to be removed due to an operating impact when the is driven, the sliding resistance reduction effect by the fluorine-based resin coat layer 10 is not lowered.

  As the low friction plastic material, for example, tetrafluoroethylene resin: PTFE, polytrifluoroethylene chloride: PCTFE, polyvinylidene fluoride: PVDF, polyvinyl fluoride: PVF, polytetrafluorohexafluoroethylene: FEP One or more fluorine-based resins of ethylene-tetrafluoroethylene resin: ETFE and tetrafluoro-perfluoroalkyl vinyl ether resin: PFA are desirable. Further, molybdenum disulfide or the like may be used as the low friction plastic material instead of the fluorine-based resin.

[Modification]
In the present embodiment, the housing of the air flow control valve of the present invention, the drive shaft and the valve body are valves for an idle speed control valve for controlling the intake air amount that bypasses the engine throttle valve during engine idle operation. Although used as the housing 1, the rotor shaft 2 and the rotary valve 3, the housing, the drive shaft and the valve body of the air flow control valve of the present invention are driven by a drive motor in accordance with the accelerator operation amount of the driver, so The present invention may be applied to a throttle body, a throttle shaft, and a throttle valve of an intake control device for an internal combustion engine that controls the amount of intake air taken into the combustion chamber of the cylinder. A throttle body of an intake throttle device for an internal combustion engine that controls an intake air amount that is sucked into a combustion chamber of a cylinder of the internal combustion engine by driving an accelerator lever (rotary drive body) according to an accelerator operation amount of a driver; You may apply to a throttle shaft and a throttle valve. Further, the present invention may be applied to a valve housing, a valve shaft, and a valve of an exhaust gas recirculation device for recirculating a part of engine exhaust gas from an exhaust passage to an intake passage.

  In this embodiment, the bearing portion 23 of the rotary valve 3 is provided on the side where the clearance between the housing wall surface of the seal wall portion 9 of the valve housing 1 and the opposing wall surface of the seat portion 21 of the rotary valve 3 is increased, that is, the rotor shaft 2. An elliptical spring 4 is used as the valve body urging means for applying the urging force on the valve opening side (the left direction in the figure) of the fitting portion 19 in the radial direction. Other elastic bodies such as springs, plate springs, rubber elastic bodies, wave washers, air cushions, etc. may be used.

It is the schematic which showed the main structures of the air flow control valve (Example 1). (A) is the schematic diagram which showed the valve position of the rotary valve at the time of an engine stop (Example 1). (B) is a schematic diagram showing the valve position of the rotary valve during engine idling (Example 1). (A) is the schematic diagram which showed the valve position of the rotary valve at the time of normal operation of an engine (Example 1). (B) is a schematic diagram showing the valve position of the rotary valve during engine idling (Example 2). It is sectional drawing which showed the idle rotational speed control valve (prior art). It is sectional drawing which showed the intake throttle device for internal combustion engines (prior art).

Explanation of symbols

S Minute clearance 1 Valve housing (housing)
2 Rotor shaft (drive shaft)
3 Rotary valve (valve)
4 Spring (valve biasing means)
5 Bypass passage (air passage)
9 Valve housing seal wall 10 Fluorine resin coating layer (low friction plastic material)
11 Air inlet (opening)
12 Air passage (opening, air outlet)
DESCRIPTION OF SYMBOLS 19 Fitting part of rotor shaft 21 Seat part of rotary valve 22 Pair of valve holding parts of rotary valve 23 Bearing part of rotary valve 24 Fitting hole of rotary valve

Claims (8)

(A) a housing having an air passage through which air passes;
(B) a drive shaft rotatably accommodated in the housing;
(C) In an air flow rate control valve provided with a valve body that is fitted to the outer periphery of the drive shaft and adjusts the flow rate of air passing through the air passage port by changing the opening area of the air passage port. ,
The housing is provided so that the valve body is disposed opposite to each other with a predetermined clearance when the valve body is in a closed position where the opening area of the air passage opening is minimized, and surrounds the air passage opening. Having a sealed wall portion,
The drive shaft has a fitting portion for fitting the valve body,
The valve body has a bearing portion that forms a minute gap in a radial direction substantially orthogonal to the thrust direction of the fitting portion between the valve body and the fitting portion,
Valve body urging means for urging the valve body toward the valve opening side in the radial direction is installed so that the clearance is increased when the valve body is in a valve closing position that minimizes the opening area of the air passage opening. An air flow control valve characterized by that. The air flow control valve according to claim 1,
The housing is assembled to an intake pipe that forms an intake passage communicating with a combustion chamber of an internal combustion engine,
An air flow control valve, wherein an air passage that bypasses a throttle valve that opens and closes the intake passage is formed in the housing. The air flow control valve according to claim 2,
The biasing force of the valve body biasing means is larger than the suction force on the valve closing side in the radial direction that acts on the valve body when the air pressure in the intake pipe is a low negative pressure or a medium negative pressure less than a predetermined value. And is set to be smaller than the suction force on the valve closing side in the radial direction acting on the valve body when the air pressure in the intake pipe is a high negative pressure equal to or higher than a predetermined value. Air flow control valve characterized by. The air flow control valve according to claim 2,
The seal wall portion of the housing is formed with a low-friction plastic material for reducing the adhesion force of foreign matter contained in the intake air in the intake passage and the air passage and increasing the separation force of the foreign matter. An air flow control valve characterized by The air flow rate control valve according to claim 4,
The radial minute gap is characterized in that the gap dimension is set so that the valve body comes into front contact with the low friction plastic material when the air pressure in the intake pipe is a high negative pressure of a predetermined value or more. Flow control valve. In the air flow rate control valve according to claim 4 or 5,
The air flow control valve according to claim 1, wherein the low friction plastic material is formed to be thin below a predetermined value capable of minimizing the influence on valve leakage. In the air flow control valve according to any one of claims 4 to 6,
The air flow control valve, wherein the low friction plastic material is formed to be thicker than a foreign substance. In the air flow control valve according to any one of claims 1 to 7,
The valve body is supported so as to be slidable in a radial direction with respect to the drive shaft and to be relatively unrotatable with respect to the drive shaft. The air flow rate control valve is a rotary valve that adjusts the flow rate of the air that passes through the air passage port by changing.

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