JPH1113603A - Idle speed control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of defective operation of a valve element and lodging of a foreign matter by a method wherein a clearance is varied between during engine operation and during a stop of an engine. SOLUTION: A drive shaft 7 on which a valve element 6 is attached is rotatably supported through ball bearings 11 and 12, and axially moved by an axial gap between ball bearings 11 and 12. During operation of an engine, a negative pressure in an intake sir piper is exerted on a closing plate 6c of the valve element 6. Since the component of force of a negative pressure in an intake pipe is higher than a suction forced exerted between the core 19 of an electromagnetic coil device and a permanent magnet 16, a drive shaft 7 is moved to the right togetherwith of the valve element 6, and a clearance between the closing plate 6c and the wall surface 9c of a valve chamber 9 is decreased. Since, during the stop of an engine, a negative pressure in an intake pipe is rendered ineffective, a drive shaft 7 is moved to the left togetherwith the valve element 6 through a suction force exerted between the core 19 and the permanent magnet 16 and a clearance between the closing plate 6c and the wall surface 9a of the valve chamber 9 is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control device for controlling an idle speed by adjusting an intake air flow rate during an idle operation of an engine.

[0002]

2. Description of the Related Art As a prior art, for example, Japanese Patent Publication No. 5-34
No. 518 discloses an electromagnetic actuator. The actuator includes a bypass passage that bypasses a throttle valve of an intake pipe, a rotary valve that opens and closes an opening provided in the bypass passage, and a driving device that drives the rotary valve. As shown in FIG. 13, the rotary valve 100 includes a bearing 200,
A closing surface 110 is provided so as to be rotatable integrally with the rotating shaft 300 rotatably supported by 210, and can close an opening 410 formed in the housing 400, and the closing surface 110 is a wall surface 420 of the housing 400. Move (rotate) along the line, the relative position with respect to the opening 410 changes, and the opening area of the opening 410 is varied.

[0003]

However, in the above-described actuator, the clearance between the wall surface 420 of the housing 400 and the closing surface 110 of the valve 100 is constant and the clearance is small (for example, 70 μm). If the soot, abrasion powder or the like (hereinafter referred to as “depot”) adheres to the closing surface 110 of the valve 100 by returning from the engine, the following problem occurs. If the engine is started at a very low temperature in a state where a large amount of deposits adhere to the closing surface 100, the operation of the valve 100 may be hindered because the viscosity of the deposits is high. Further, if the deposit is left for a long time in a state where a large amount of the deposit is attached, the oxidation of the deposit is facilitated and the deposit is easily fixed, and as a result, the valve 100 may not be able to operate. Also, the wall surface 420 of the housing 400
And the clearance between the closing surface 110 of the valve 100 is constant.
There is no place for foreign matter to escape, and the valve 100 locks.

Further, in the structure of the actuator, the wall surface 420 of the housing 400 and the closed surface 1 of the valve 100 are provided.
Since the clearance with 10 is determined by the combination of the accuracy of each component, it cannot be said that a certain clearance can always be secured. That is, since the clearance varies due to variations in the accuracy of each component, it is difficult to reduce valve leakage (air leaks and flows from the clearance). The present invention has been made based on the above circumstances, and an object of the present invention is to provide an idling device that prevents a malfunction of a valve body and a foreign object from being caught by varying a clearance between an engine operation and an engine stop. It is to provide a rotation speed control device.

[0005]

[Means for Solving the Problems]

(Means of Claim 1) The valve body is provided so as to be displaceable in a clearance direction between a wall surface on which an opening is formed and a closed surface, and the clearance is larger when the engine is stopped than when the engine is running. it can. In this case, even if the depot adheres to the closing surface of the valve body during operation of the engine, the depot separates from the wall surface having the opening formed by increasing the clearance when the engine is stopped (or the depot adheres to the wall surface). Also, the depot separates from the closed surface), so that the valve body does not lock even at the time of cryogenic start in which the viscosity of the depot becomes high. Further, even if the depot adheres to the closed surface due to long-term storage, the valve does not lock. Further, in the present invention, since the valve element can be displaced in the clearance direction, even if a foreign object enters the clearance during operation of the engine, the valve element is displaced in the direction in which the clearance increases, so that a clearance area for the foreign object can be secured. Therefore, there is no possibility that the valve body is locked by the foreign matter being caught. On the other hand, during engine operation, valve leakage can be reduced by reducing the clearance.

According to the present invention, according to the present invention, during operation of the engine, the negative pressure of the intake pipe acting on the valve body overcomes the force generated by the valve body moving means, thereby reducing the clearance of the valve body. When the engine is stopped, there is no negative pressure in the intake pipe. Therefore, the valve element can be displaced in a direction to increase the clearance by the force generated by the valve element moving means. As a result, it is possible to prevent malfunction of the valve body due to the adhesion of the deposit and to prevent foreign matter from being caught.

The opening is formed obliquely with respect to the direction of air flow, the valve body is provided integrally with the rotating shaft so as to be movable in the axial direction, and the closing surface is open. It is provided to be inclined so as to be parallel to the part. In this case, by moving the valve body in the axial direction, the clearance between the closed surface of the valve body and the wall surface on which the opening is formed can be changed. Therefore, during engine operation, the axial component of the intake pipe negative pressure acting on the closing surface overcomes the force generated by the valve body moving means, and moves the valve body together with the rotary shaft in a direction in which the clearance decreases, and the engine At the time of stop, the rotating shaft and the valve element are moved in a direction to increase the clearance by the force generated by the valve element moving means. As a result, it is possible to prevent a malfunction of the valve body due to the adhesion of the deposit and a biting of foreign matter.

According to a fourth aspect of the present invention, the valve body moving means comprises a permanent magnet provided on a rotating shaft and a magnetic material disposed on the outer periphery of the permanent magnet. When the rotation shaft moves to a position facing the position, the clearance becomes maximum. In this case, during the operation of the engine, the force that moves the valve body in the direction of decreasing the clearance (the axial component force of the negative pressure of the intake pipe acting on the closing surface of the valve body) is increased in the direction of increasing the clearance. Is larger than the force (magnetic force of the permanent magnet acting on the magnetic material), the valve body moves in the axial direction together with the rotating shaft, and the clearance can be reduced. At this time, the permanent magnet provided on the rotary shaft is shifted by a predetermined amount in the axial direction from a position radially facing the magnetic material. When the engine stops,
Since the intake pipe negative pressure is eliminated, the rotation axis moves to a position where the magnetic material and the permanent magnet oppose each other in the radial direction by the magnetic force of the permanent magnet acting on the magnetic material, thereby maximizing the clearance. The same effect can be obtained by providing a magnetic material on the rotating shaft and disposing a permanent magnet on the outer periphery of the magnetic material.

(Means of Claim 5) The valve body moving means is a spring which presses the rotating shaft in the axial direction. In this case, the pressing force of the spring pressing the rotating shaft is set to a value smaller than the axial component force of the negative pressure of the intake pipe acting on the closing surface of the valve body during operation of the engine. Therefore, when the engine is operating, the axial component of the intake pipe negative pressure acting on the closing surface of the valve body overcomes the pressing force of the spring, so that the valve body can be moved in a direction in which the clearance becomes smaller. Also,
When the engine stops and there is no negative pressure in the intake pipe, the rotating shaft is pressed by the pressing force of the spring, so that the rotating shaft and the valve element move in the axial direction to increase the clearance.

(Means of Claim 6) There is a position adjusting means for adjusting the axial position of the valve body. In this case, the clearance can be finely adjusted by adjusting the axial position of the valve body by the position adjusting means. As a result, even if the accuracy of each component constituting the apparatus varies, the clearance during engine operation can be kept constant, and it is difficult to easily reduce valve leakage.

[0011]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an idle speed control device 1
FIG. The idle speed control device 1 of the present embodiment adjusts the amount of air that bypasses the throttle valve 3 of the intake pipe 2 (see FIG. 2) during idle operation of the engine, and includes a housing 5 that forms a bypass passage 4, A valve body 6 that changes the passage area of the bypass passage 4, a drive shaft 7 that supports the valve body 6 (a rotating shaft of the present invention), and an electromagnetic coil device 8 that rotationally drives the drive shaft 7 (a driving unit of the present invention). Etc.

The housing 5 is formed of, for example, a non-magnetic material such as a synthetic resin or aluminum, is attached to the intake pipe 2, and is fixed by tightening screws (not shown). As shown in FIG. 2, the bypass passage 4 has one end open to the air upstream of the throttle valve 3 of the intake pipe 2 and the other end open to the air downstream of the throttle valve 3 of the intake pipe 2. Is bypassed. Also,
A cylindrical valve chamber 9 that accommodates the valve body 6 is provided in the middle of the bypass passage 4, and an opening 10 is formed in a wall surface 9 a of the valve chamber 9. However, this opening 10 is
As shown in FIG. 1, the opening is oblique to the direction of air flow.

The valve element 6 is supported by a drive shaft 7 and
A rotary valve provided so as to be able to rotate integrally with the
As shown in FIG. 1, two support plates 6 fixed to a drive shaft 7 are provided.
a, 6b and a closing plate 6c provided between the two support plates 6a, 6b, and the opening area of the opening 10 is changed by the closing plate 6c. The closing plate 6c has the opening 1
0 has a surface area large enough to cover the entire surface, and the wall 9a of the valve chamber 9 in which the opening 10 is formed and the closing plate 6
c is inclined with respect to the drive shaft 7 so that a clearance C (see FIG. 3) between the drive shaft 7 and the opening c is constant (parallel to the opening 10). As shown in FIG. 5, the surface of the closing plate 6c is formed as a convex curved surface (arc surface) along the circumference.

The drive shaft 7 is fixed to the housing 5.
It is rotatably supported via the ball bearings 11 and 12, and the valve element 6 is mounted between the two ball bearings 11 and 12. The drive shaft 7 is movable in the axial direction by the axial gap between the ball bearings 11 and 12, and the position in the axial direction can be adjusted by a screw 13 provided at one end of the drive shaft 7. The screw 13 is disposed between the screw 13 and the drive shaft 7 via a ball 14 and a washer 15, and is screwed to a female screw portion formed in the housing 5. Further, a cylindrical permanent magnet 16 is fitted to the other end of the drive shaft 7 protruding outward (left side in FIG. 1) from one of the ball bearings 12 so as to rotate integrally with the drive shaft 7. ing. The permanent magnet 16 is magnetized so that one side in the radial direction has an N pole and the other side has an S pole (see FIGS. 1 and 4).

The electromagnetic coil device 8 includes a pin 17 made of a magnetic material having a circular cross section, a coil 18 wound around the pin 17, a magnetic core 19 forming a magnetic circuit together with the pin 17, and a mold made of these. Resin cover 20
And is fixed to the housing 5 by tightening screws (not shown). The energization of the coil 18 is controlled through an engine control device (hereinafter, referred to as an ECU) not shown. However, the exciting current to the coil 18 is determined by the ratio between the open duty and the closed duty as shown in FIG.
The magnitude and direction of the current flowing through 8 change (to be described later).

As shown in FIG. 4, the core 19 is provided with a substantially U-shaped cross section connected to both end faces of the pin 17, and an opening 21 is formed in a portion parallel to the pin 17. The other end of the drive shaft 7 having the permanent magnet 16 is inserted through the inner periphery of the opening hole 21. The opening hole 21 has an inner diameter slightly larger than the outer diameter of the permanent magnet 16, and is formed with a detent groove 22 that is depressed in a semicircular shape on both sides in the direction in which the magnetic flux passes (the left-right direction in FIG. 4). . The axial length of the permanent magnet 16 and the axial length of the core 19 (width in the left-right direction in FIG. 1) are set to substantially the same dimensions.

In the electromagnetic coil device 8, the amount and direction of the magnetic flux flowing through the magnetic circuits (17, 19) are changed by controlling the exciting current supplied to the coil 18 through the ECU. The drive shaft 7 can be rotationally driven by applying a rotational force to the drive shaft 16. Here, the relationship between the magnetic flux passing through the magnetic circuit and the permanent magnet 16 will be described. When the exciting current is not supplied to the coil 18,
As shown in FIG. 7A, a magnetic flux loop generated by the magnetism of the permanent magnet 16 is formed around the opening 21. However, the permanent magnet 16 stops at a position where the distance between each of the N and S magnetic poles and the core 19 is the smallest. On the other hand, when the exciting current is supplied to the coil 18 based on the duty ratio, a magnetic flux loop passing through the magnetic circuit is formed. At this time, since the magnetic flux passing through the core 19 has an opening 21 formed in the core 19 and the cross-sectional area of the magnetic flux passage is small, the magnetic flux passing through this portion is saturated, and a part of the magnetic flux is
You will pass through 6.

For example, when the duty ratio is higher than 50%, as shown in FIG. 7B, a one-way magnetic flux loop is formed in the magnetic circuit, and the S pole is formed on one side of the detent groove 22a and the other is formed on the side of the detent groove 22a. An N pole is formed on the side of the detent groove 22b. As a result, the permanent magnet 16 rotates counterclockwise according to the amount of magnetic flux passing therethrough. When the duty ratio is lower than 50%, as shown in FIG. 7C, when a magnetic flux loop in the other direction is formed in the magnetic circuit, an N pole is formed on one side of the detent groove 22a and the other detent groove 22b is formed. , The permanent magnet 16 rotates clockwise according to the amount of magnetic flux passing therethrough. When the duty ratio is 50%, the direction of the magnetic flux changes alternately. As a result, as in the case where the exciting current is not supplied to the coil 18, the permanent magnet 16 And the core 19 is stopped at a position where the distance between the core and the core 19 is minimized.

Next, the relationship between the exciting current supplied to the coil 18 and the rotation angle of the valve body 6 and the flow rate of air passing through the opening 10 will be described. The exciting current supplied to the coil 18 is determined according to the duty ratio as shown in FIG. That is, the current value when rotating the valve 6 in the direction to open the opening 10 is determined by the open duty corresponding to the Lo time in FIG.
Is determined by the close duty corresponding to the Hi time in FIG.

As shown in FIG. 9, the relationship between the exciting current supplied to the coil 18 and the rotation angle of the valve element 6 depends on the current value obtained with an open duty based on the current value = 0. The valve element 6 rotates in a direction to open the opening 10,
It rotates about 35 degrees from the reference position at the maximum current (+0.3 A). At this time, the valve 6 opens 100% of the opening 10 (see FIG. 5C). On the other hand, the valve element 6 rotates in the direction to close the opening 10 according to the current value obtained by the close duty, and rotates by about 35 degrees from the reference position at the minimum current (-0.3 A). At this time, the valve element 6 has already been opened.
0 is 100% closed (see FIG. 5A).

Further, as for the relationship between the rotation angle of the valve body 6 and the air flow rate, as shown in FIG. 10, when the rotation angle of the valve body 6 = 0, the air flow rate passing through the opening 10 is 1 / the maximum flow rate. The setting is such that the maximum flow rate is obtained when the valve element 6 rotates 35 degrees in the direction in which the opening 10 is opened. That is, the valve body 6 has a rotation angle = a position where the opening 10 is closed about 2/3.
It is set to be 0. When the above relationships are integrated, a relationship between the duty ratio and the air flow rate is established as shown in FIG.

Next, the operation of this embodiment will be described. a) When the engine is stopped When the engine is stopped, it is not necessary to control the idle rotation speed, so that no exciting current is supplied to the coil 18. In this case, the permanent magnets 16 provided on the drive shaft 7 have their magnetic poles N and S most in the circumferential direction as shown in FIG. 4 due to the attractive force (magnetic force of the permanent magnet 16) acting between the core 19 and the permanent magnet 16. As shown in FIG. 3, the core 19 and the permanent magnet 16 are aligned (the core 19 and the permanent magnet 16 are not displaced in the axial direction) as shown in FIG. At this time, the drive shaft 7 is moved to the left side in FIG. 1 by the axial gap described above. Also,
5B, the closing plate 6c closes the opening 10 by about 2/3 as shown in FIG. 5B, and moves to the left in FIG. The clearance C between the valve body 9 and the wall surface 9a of the valve chamber 9 is widened.

B) At the time of engine operation (at the time of non-idle operation) Since the amount of air taken into the engine is determined by the opening degree of the throttle valve 3, the valve body 6 is driven to rotate so that the opening 10 is fully closed. (See FIG. 5A). In this case, the negative pressure of the intake pipe acts on the closing plate 6c of the valve body 6, and the axial component of the negative pressure of the intake pipe is larger than the attractive force acting between the core 19 and the permanent magnet 16. Moves to the right in FIG. As a result, the clearance C between the closing plate 6c of the valve body 6 and the wall surface 9a of the valve chamber 9 decreases.

C) At the time of engine operation (at the time of idling operation) In this case, the opening of the valve body 6 is controlled according to the amount of air required at the time of idling operation. That is, the duty ratio of the exciting current supplied to the coil 18 is determined according to the required air amount, and the valve element 6 rotates by a predetermined angle according to the duty ratio. Note that the duty ratio of the exciting current corresponding to the air amount is based on detection signals from sensors for detecting the load state of accessories (for example, a compressor of an air conditioner) coupled to the engine, the cooling water temperature of the engine, and the like. It is calculated by the ECU. For example, when the air conditioner is turned on and the engine load is large, the amount of bypass air is determined to be increased. Even during this idling operation, the intake pipe negative pressure acts on the closing plate 6c of the valve body 6,
The drive shaft 7 is driven by the valve body 6 by the axial component force of the intake pipe negative pressure.
And moves to the right side in FIG. As a result, the clearance C between the closing plate 6c of the valve body 6 and the wall surface 9a of the valve chamber 9 is increased.
Becomes smaller.

(Effects of the present embodiment) In the present embodiment, by moving the drive shaft 7 in the axial direction, the wall 9a of the valve chamber 9 in which the opening 10 is formed and the closing plate 6c of the valve 6 are connected. The clearance C between them can be changed. That is, when the engine is operating, the clearance C can be reduced by the intake pipe negative pressure acting on the closing plate 6c, and when the engine is stopped, the clearance C can be increased by eliminating the intake pipe negative pressure. As a result, during operation of the engine, the valve 6
Even if a deposit adheres to the closing plate 6c, the clearance C is increased when the engine is stopped, thereby separating the deposit from the wall surface 9a of the valve chamber 9 in which the opening 10 is formed (or the deposit is attached to the wall surface 9a). However, since the deposit is separated from the closing plate 6c), the valve body 6 is not locked even at the time of cryogenic start in which the viscosity of the deposit becomes high.

Further, even if the deposit is fixed to the closing plate 6c by leaving it for a long period of time, the valve body 6 is not locked. Further, in the present embodiment, the valve body 6 can move in the direction of the clearance C integrally with the drive shaft 7, so that the closing plate 6c of the valve body 6 and the wall 9
Even if a foreign matter enters between the valve body a and the valve body 6, the clearance of the foreign matter can be secured by displacing the valve body 6 in a direction in which the clearance C increases. Therefore, there is no possibility that the valve body 6 is locked due to foreign matter being caught. Furthermore, the clearance C can be finely adjusted by adjusting the position of the drive shaft 7 in the axial direction with the screw 13. As a result, even if the accuracy of each component constituting the apparatus varies, the clearance C during engine operation can be kept constant, and it is difficult to easily reduce valve leakage.

(Second Embodiment) In this embodiment, as shown in FIG. 12, a screw 1 for adjusting the thrust position of the drive shaft 7 is used.
A spring 23 is interposed between the shaft 3 and the washer 15 to constantly bias the drive shaft 7 in the axial direction. That is, when the engine is stopped, the drive shaft 7 is moved in the direction in which the clearance C is increased by the spring force of the spring 23 (see FIG.
2 left direction). In the first embodiment, the drive shaft 7 is driven to rotate by the electromagnetic coil device 8, but the present invention is not limited to the electromagnetic coil device 8. That is, the drive shaft 7 can be moved (in a direction in which the clearance C increases) by the spring force of the spring 23 without using the attraction force acting between the permanent magnet 16 and the core 19. Drive means other than 8 can be used. (Please provide any specific examples.)

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an idle rotation speed control device during engine operation.

FIG. 2 is a schematic diagram showing a bypass passage.

FIG. 3 is a cross-sectional view of the idle speed control device when the engine is stopped.

FIG. 4 is a cross-sectional view of the electromagnetic coil device.

FIG. 5 is a sectional view showing an operating state of a valve body.

FIG. 6 is a diagram illustrating a relationship between a duty signal and a current value.

FIG. 7 is a diagram illustrating an operation state of the electromagnetic coil device.

FIG. 8 is a graph showing a relationship between a duty ratio and a current value.

FIG. 9 is a graph showing a relationship between a current value and a rotation angle of a valve body.

FIG. 10 is a graph showing a relationship between a rotation angle of a valve body and an air flow rate.

FIG. 11 is a graph showing a relationship between a duty ratio and an air flow rate.

FIG. 12 is a cross-sectional view of an idle speed control device showing a second embodiment of the present invention.

FIG. 13 is a sectional view of a conventional idle rotation speed control device.

[Explanation of symbols]

 C Clearance 1 Idle rotation speed control device 2 Intake pipe 3 Throttle valve 4 Bypass passage 6 Valve 6c Closure plate (closure surface) 7 Drive shaft (rotation shaft) 8 Electromagnetic coil device (drive means) 9a Wall surface of valve chamber (opening) 10 Opening 13 Screw (Position Adjusting Means) 16 Permanent Magnet (Valve Moving Means) 19 Core (Magnetic Material / Valve Moving Means) 23 Spring (Valve Moving Means)

Claims (6)

[Claims] 1. A bypass passage bypassing a throttle valve and communicating with an intake pipe, an opening provided in the bypass passage, and an obstruction provided displaceably along a wall surface on which the opening is formed. A valve body that varies the opening area of the opening in accordance with the position of the closed surface. The valve body varies the opening area of the opening to change the air flow rate flowing through the bypass passage. An idle rotation speed control device for controlling, wherein the valve body is provided so as to be displaceable in a clearance direction between a wall surface on which the opening is formed and the closed surface, and the valve body is more displaced when the engine is stopped than when the engine is operated. Increases the clearance. 2. A bypass passage that bypasses a throttle valve and communicates with an intake pipe, an opening provided in the bypass passage, and an obstruction provided to be displaceable along a wall surface on which the opening is formed. A valve body that varies the opening area of the opening in accordance with the position of the closed surface. The valve body varies the opening area of the opening to change the air flow rate flowing through the bypass passage. An idle rotation speed control device for controlling, wherein the valve body is provided so as to be displaceable in a clearance direction between a wall surface on which the opening is formed and the closing surface, and the valve is disposed in a direction in which the clearance increases. A valve body moving means for generating a force for moving the body, during engine operation, the intake pipe negative pressure acting on the valve body overcomes the force generated by the valve body moving means,
Idle rotation speed control characterized by displacing the valve body in a direction in which the clearance becomes smaller, and displacing the valve body in a direction in which the clearance becomes larger by a force generated by the valve body moving means when the engine is stopped. apparatus. A bypass passage which bypasses the throttle valve and communicates with the intake pipe; an opening provided in the bypass passage; and an obstruction provided rotatably along a wall surface on which the opening is formed. A valve body having a surface and varying the opening area of the opening in accordance with the position of the closing surface; a rotating shaft rotatably supporting the valve body; and a driving unit for rotatingly driving the rotating shaft. An idle rotation speed control device that controls an air flow rate flowing through the bypass passage by varying an opening area of the opening by the valve body, wherein the opening opens obliquely to a direction of air flow. The valve body is provided so as to be movable in the axial direction integrally with the rotating shaft, and the closing surface is provided to be inclined so as to be parallel to the opening, and the opening is formed. Between the wall and the closed surface A valve body moving means for generating a force for moving the rotary shaft and the valve body in a direction in which the clearance increases, and when the engine is operating, the axial component of the intake pipe negative pressure acting on the closing surface is the valve. The valve body is moved integrally with the rotary shaft in a direction in which the clearance is reduced by overcoming the force generated by the body moving means. When the engine stops, the rotary shaft and the valve are moved by the force generated by the valve body moving means. An idle speed control device for moving a body in a direction in which the clearance increases. 4. The valve body moving means includes a permanent magnet provided on the rotating shaft and a magnetic material disposed on an outer periphery of the permanent magnet, wherein the permanent magnet and the magnetic material are arranged in a radial direction. The idle rotation speed control device according to claim 2, wherein the clearance is maximized when the rotation shaft moves to an opposing position. 5. The valve moving means according to claim 2, wherein said valve body moving means is a spring for pressing said rotary shaft in an axial direction.
Or the idle rotation speed control device described in 3. 6. An idle speed control device according to claim 1, further comprising a position adjusting means for adjusting an axial position of said valve element.