JPH0424114Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention was developed in an air control system for an internal combustion engine, in particular for the purpose of reducing friction in the throttle valve actuation system. This invention relates to a throttle valve support structure in which the throttle valve is rotatably supported by a ball bearing.

<Prior art> As a support structure for this type of throttle valve, for example, Japanese Patent Application Laid-open No. 129538/1983 (hereinafter referred to as "first publication")
Alternatively, the technique disclosed in Japanese Utility Model Publication No. 60-26201 (hereinafter referred to as "second publication") can be mentioned.

The technique of the first publication is such that the inner ring of a bearing that rotatably supports the throttle shaft is brought into contact with an abutting part provided on the throttle valve shaft, and the outer ring is engaged with an engaging part provided on the throttle body. It is now possible to combine A spring such as a web washer is disposed between the outer ring of at least one of the bearings and the corresponding engaging portion.

In other words, a small gap exists between the throttle valve shaft and the inner ring of the bearing. Note that the outer rings of both bearings are a close fit to the throttle body.

Further, in the technique of the second publication, the outer ring of the bearing supporting the throttle valve ring is press-fitted into the body, and the throttle valve shaft is inserted into the inner ring with a slight gap.

<Problems to be solved by the invention> In general, the body of an air control device (throttle body) is attached directly or indirectly to an internal combustion engine, so it is susceptible to vibrations from the internal combustion engine, and is subject to greater vibrations than the internal combustion engine.

Under such conditions, the technique of the first publication applies preload to the inner and outer rings of both bearings in the axial direction of the throttle valve shaft, thereby moving the throttle valve shaft and bearing against the throttle body. Although the axial direction of the throttle valve shaft is fixed, the outer ring of the bearing and the body are fitted with each other. Therefore, when vibrations from the internal combustion engine are applied to the body, the body and both bearings vibrate individually, causing wear between both bearings and the body. Additionally, this causes the distance between the throttle valve and the inner wall of the body to change, making air control unstable, and also causes wear between the throttle valve and the inner wall of the body. Wear also occurs between the body relief hole and the air control becomes unstable.

Such a problem occurs when the vibration acceleration applied to the throttle valve shaft is large, and this problem can be avoided by setting a large preload on the spring, but in that case, the throttle valve can be fixed using a ball bearing. The original purpose of reducing friction in the valve actuation system would be defeated.

In addition, in the technology of the second publication, the inner ring of the bearing and the throttle valve shaft are a close fit, which causes wear between the throttle valve shaft and both bearings, resulting in the same problem as in the first publication mentioned above. occurs.

Therefore, in view of the above problems, the present invention has an object to provide a support structure for a throttle valve in an air control device that can prevent wear between the bearing and the body and between the bearing and the throttle valve shaft. do.

<Means for Solving the Problems> The present invention is configured as follows in order to solve the above problems.

First, a throttle valve shaft having a throttle valve attached to the body of the air control device is rotatably supported by ball bearings on both sides of the throttle valve. Of the two ball bearings, the inner ring of one of the ball bearings is press-fitted into the throttle valve shaft. The inner ring of the other ball bearing is loosely fitted to the throttle valve shaft, and each outer ring of both ball bearings is loosely fitted to the body.

Further, both end surfaces of the ball bearing on the side where the inner ring is press-fitted into the throttle valve shaft are connected to a locking portion formed on the body and a spring disposed on the end surface of the stopper member press-fitted into the body. It is held in a state where a thrust is applied by a stopper member attached to the body through a screw or a screw. As a result, the outer ring is not only fixed in the axial direction, but also in a direction perpendicular to the axial direction, that is, in the radial direction, by the frictional force caused by the thrust.

Furthermore, both end surfaces of the outer ring of the ball bearing on the side where the inner ring is fitted onto the throttle valve shaft are held between a locking part formed on the body and a stopper member press-fitted into the body. This makes it fixed in the axial direction.

Further, the outer ring of the ball bearing, the inner ring of which is press-fitted into the throttle valve shaft, has a groove formed on its outer periphery, and a material having a coefficient of thermal expansion that is the same or similar to that of the material of the body is integrally formed in the groove, This may be press-fitted and fixed to the body.

<Function> According to the above configuration, when the air control device receives vibrations from the internal combustion engine, the body, ball bearing, and throttle valve shaft vibrate as a unit in the axial direction and radial direction of the throttle valve shaft. I will do it. Therefore,
Wear is prevented between the throttle valve shaft and the ball bearing, and between the ball bearing and the body.

In addition, the body, ball bearing, and throttle valve shaft always vibrate as a unit, which means that the distance between the throttle valve and the inner wall of the body is always maintained constant, and the throttle valve opens and closes as the throttle valve opens and closes. Abrasion between the inner wall and the inner wall of the body is also prevented.

Furthermore, the inner ring of one ball bearing is attached to the throttle valve shaft.
According to the structure in which the outer rings of both ball bearings are fitted in the body, it is easy to assemble the throttle valve shaft and the ball bearings to the body. Moreover, this means that even if there is an error in the centering accuracy of the part of the body where both ball bearings are installed,
This can be absorbed by the slight gap caused by the above-mentioned interfit.

<Example> Next, embodiments of the present invention will be described with reference to the drawings.

First Embodiment FIG. 1 shows a cross section of an air control device arranged in an intake system of a vehicle internal combustion engine, FIG. 2 shows a part of the right side of FIG. 1, and FIG. In FIG. 3, which is shown in FIG. 3, and FIG. 4, which is viewed from the direction of arrow A in FIG. ,
It is designed to be fed through the opening at the top of the drawing. This intake air is then fed to body 1 at the bottom of the drawing.
The fuel passes through an intake manifold (not shown) connected to the opening of the engine 0, and is supplied to each cylinder of the internal combustion engine together with fuel injected from, for example, an injector (not shown).

A throttle valve shaft 30 is attached to the body 10 so as to be perpendicular to an intake passage therein. A slit 30a is formed in a portion of the throttle valve shaft 30 located inside the body 10. A throttle valve 32 is assembled into this slit 30a and fixed by a screw 34. That is, the throttle valve 32 is located within the intake passage of the body 10.
Note that the minute distance between the throttle valve 32 and the inner wall of the intake passage of the body 10 is normally set to 0.1 mm or less.

Further, the throttle valve shaft 30 is connected to the body 10 by ball bearings 16 and 16 on both sides of the throttle valve 32, respectively.
It is rotatably supported by 17. As is well known, these ball bearings 16, 17 are arranged between inner rings 16a, 17a and outer rings 16b, 17b.
Each has a configuration in which a plurality of balls 16c and 17c are interposed. Both of these ball bearings 16 and 17 are respectively installed inside a sleeve portion 14 that constitutes a bearing installation space on both the left and right sides of the body 10.

Of the two ball bearings 16 and 17, the ball bearing 16 located on the left side in FIG.
(0.1mm or less) is an interfit.
On the other hand, the inner ring 17a of the ball bearing 17 located on the right side in FIG. 1 is fixed to the outer periphery of the throttle valve shaft 30 by press fitting.

Further, the respective outer rings 16b and 17b of both ball bearings 16 and 17 are slightly spaced apart from the inner peripheral surfaces of both sleeve portions 14 of the body 10.
(0.1mm or less).

A stopper member 18 formed in an annular shape is press-fitted into the inner periphery of the sleeve portion 14 located on the left side of the body 10 in FIG. As a result, the outer ring 16b of the ball bearing 16 is held between the stopper member 18 and the locking portion 11, which is formed in a stepped shape on the inner circumference of the sleeve portion 14.
That is, the outer ring 16b of the ball bearing 16 is fixed to the body 10 in the axial direction.

On the other hand, on the inner periphery of the sleeve portion 14 located on the right side of the body 10 in FIG. It is pressed into position. This stopper member 19 consists of a thin annular portion 19a with a large inner diameter and a thick annular portion 19b with a small inner diameter.
mm or less), and is fitted almost to the center of the outer ring 17b in the axial direction. Note that the outer periphery of the thin annular portion 19a is formed in a tapered shape to prevent the inner diameter from being reduced by press-fitting into the body 10.

A spring 15 made of a web washer or the like is interposed between the inner end surface of the thick annular portion 19b of the stopper member 19 and the opposing end surface of the outer ring 17b. That is, the outer ring 17b of the ball bearing 17 is connected to the body 1.
The inner periphery of the sleeve portion 14 at 0 is formed in a stepped shape. It is held between the locking portion 11 and the stopper member 19 via the spring 15. As a result, the outer ring 17b is fixed to the body 10 with a pressing force in the axial direction by the spring 15, that is, a thrust (for example, 40 to 100 kg), and at the same time, the friction force due to the thrust forces the outer ring 17b in a direction perpendicular to the axial direction. In other words, it is also fixed in the radial direction.

Further, a support 42 is placed in contact with the outer end surface of the stopper member 19 and the right end surface of the body 10, and is fixed to the body 10 by a plurality of screws 44. Positional deviation in the removal direction is suppressed.

In addition, in order to reduce the difference in thermal expansion coefficient between the stopper members 18 and 19 and the body 10,
The same aluminum as this body 10, or a material such as brass having a coefficient of thermal expansion similar to this is used.

Furthermore, oil seals 20 and 21 made of a material such as rubber are provided between the inner peripheral surfaces of the left and right stopper members 18 and 19 and the outer peripheral surface of the throttle valve shaft 30, respectively. Airtightness is maintained.

A sensor lever 36 connected to a throttle sensor (not shown) for detecting the opening of the throttle valve 32 is attached to the left end of the throttle valve shaft 30 located outside the body 10. This sensor lever 36 is fixed to the throttle valve shaft 30 by a nut 38 that is tightened to a male threaded portion at the end of the throttle valve shaft 30.

On the other hand, a throttle valve shaft 30 located outside the body 10
An accelerator lever 50 is fixed to the right end of the throttle valve shaft 30 by a nut 52 that is tightened to a male thread at the end of the throttle valve shaft 30. This accelerator lever 50
The operating force of an accelerator pedal (not shown) is transmitted through an accelerator wire or the like, and the throttle valve 32 is opened and closed around the axis of the throttle valve shaft 30.

Further, a return spring 54 is provided between the accelerator lever 50 and the body 10 for returning the accelerator lever 50 to its original position (initial position).
is attached to the outer periphery of the throttle valve shaft 30 via a spring guide 56. Therefore, generally the throttle valve shaft 3
0 is the accelerator lever 50 from the right ball bearing 17
The length from the left ball bearing 16 to the accelerator lever 36 is longer than the length from the left ball bearing 16 to the accelerator lever 36.

In the above configuration, vibrations of the internal combustion engine (not shown) are transmitted to the body 10, which is directly or indirectly attached to the internal combustion engine. When the body 10 receives vibration in this way, this body 1
0, the right ball bearing 17 and the throttle valve shaft 30 vibrate together in the axial direction of the throttle valve shaft 30 or in the direction perpendicular thereto. Therefore, between the throttle valve shaft 30 and the inner ring 17a of the ball bearing 17, or between the inner ring 17b of the ball bearing 17 and the body 10,
Wear is prevented between the inner periphery of the sleeve portion 14 and between the inner periphery of the thin annular portion 17a of the stopper member 19 and the outer periphery of the right ball bearing 17. At the same time, between the locking portion 11 of the body 10 and one end surface of the ball bearing 17, and the ball bearing 1
Wear is prevented between the other end surface of the spring 7 and the spring 15 such as the web washer, and further between the spring 15 and the stopper member 19.

On the other hand, the throttle valve 32 opens and closes within the intake passage of the body 10 using the throttle valve shaft 30 as a rotation axis,
This controls the amount of air supplied to the internal combustion engine. The minute distance (0.1 mm or less) between this throttle valve 32 and the inner wall of the intake passage in the body 10 is
Since the body 10, ball bearing 17, and throttle valve shaft 30 always vibrate together, they are always kept constant. Therefore, the air control function by the throttle valve 32 is stabilized.

By the way, the accelerator lever 50 fixed to the right end of the throttle shaft 30 shown in FIG. 1 has a larger mass than the sensor lever 36 fixed to the left end, and furthermore, there is no A larger acting force is applied than on the sensor lever 36 side. Furthermore, the length of the throttle valve shaft 30 from the ball bearing 17 to the accelerator lever 50 is longer than the length from the ball bearing 16 to the sensor lever 36. Therefore, the ball bearing 17 on the right side shown in FIG. 1 bears a larger load than the ball bearing 16 on the left side. However, since the inner ring 17a of the right ball bearing 17 and the outer peripheral surface of the throttle valve shaft 30 are fixed by press fitting, it is possible to sufficiently cope with such a large load.

Further, the radial deflection due to vibration of the throttle valve shaft 30 increases as it approaches the accelerator lever 50. Therefore, the ball bearing 17 in which the inner ring 17a is press-fitted into the throttle valve shaft 30 is subjected to an axial vibration in addition to the axial force due to the vibration. Since the spring 15 is set with a force of , the axial force is absorbed by the spring 15.
Moreover, the outer ring 17b of the ball bearing 17 is connected to the body 1.
Since it is pressed against the locking portion 11 of 0 by the thrust force added by the spring 15, the frictional force controls the movement against the radial force caused by the vibration. Therefore, the ball bearing 17
Wear is prevented on the inner periphery of the sleeve portion 14 in contact with the outer ring 17b, the locking portion 11, and the inner end surface of the stopper member 19.

In addition, regarding the ball bearing 16 on the left side (sensor lever 36 side) which does not bear a very large load on the throttle valve shaft 30, its inner ring 16a and the throttle valve shaft 3
0 and between the outer ring 16b and the inner peripheral surface of the sleeve portion 14 of the body 10, the throttle valve shaft 30 can be easily assembled to the body 10. Further, the provision of a slight gap between the inner ring 16a and the outer peripheral surface of the throttle valve shaft 30 also serves the following function.

Now, suppose that the inner ring 16a of the left ball bearing 16
is press-fitted into the throttle valve shaft 30 and fixed, and if there is an error in the centering accuracy of the left and right sleeve portions 14 in the body 10, the outer ring 16b and the inner circumferential surface of the sleeve portion 14, which should originally have a slight distance between them, The relationship between the two is a partial press fit. This result is the throttle valve shaft 30
As a result, the ball bearing 16 cannot rotate smoothly.

However, if a small distance is provided between the inner ring 16a of the left ball bearing 16, which does not bear a very large load, and the outer periphery of the throttle valve shaft 30, as in this embodiment,
Such inconveniences are avoided. Further, even if a slight gap is provided between the inner ring 16a of the ball bearing 16 and the outer periphery of the throttle valve shaft 30, the load borne by them is so small that the wear between them is so slight as to hardly cause any problems.

Further, the outer ring 16b of the ball bearing 16 is held between the stopper member 18 and the locking portion 11 of the body 10, and the inner ring 16a and the throttle valve shaft 30 are fitted with each other, so that the ball bearing 16 and the body 10 are Since both vibrate as one, abrasion of each is prevented.

Furthermore, in this embodiment, both stopper members 18,
19 is press-fitted into the sleeve portion 14 of the body 10, the seal between the intake passage of the body 10 and the outside is ensured. Since they are made of materials with the same or similar values, the press-fitting allowance is maintained appropriately against temperature changes, and the sealing performance is stable.

Second Embodiment In FIG. 5, which is an enlarged view of the portion corresponding to the bearing holding portion on the right side (accelerator lever 50 side) of FIG. (0.1mm or less). The inner end surface of the stopper member 19 is in direct contact with the end surface of the outer ring 17b of the ball bearing 17, and the outer end surface is projected beyond the right end surface of the body 10. Further, a support 42 is placed in contact with the outer end surface of the stopper member 19, and is fixed to the body 10 by a plurality of screws 44.

That is, the outer ring 17b of the ball bearing 17 is held between the locking portion 11 of the body 10 and the stopper member 19 via the support 42 with a thrust being applied in the axial direction by tightening the screw 44. As a result, the outer ring 17b of the ball bearing 17 is fixed to the body 10 in both the axial direction and the radial direction. Note that the other configurations are the same as those of the first embodiment described above.

Therefore, also in this second embodiment, the body 1
When the valve 0 receives vibration, the body 10, the ball bearing 17, and the throttle valve shaft 30 vibrate together in the axial and radial directions, and perform the same function as in the first embodiment. Become.

Third Embodiment In FIG. 6, which is an enlarged view of the portion corresponding to the bearing holding portion on the right side (accelerator lever 50 side) of FIG. It is screwed into a threaded portion 14a provided on the inner periphery of the sleeve portion 14 of the body 10. The inner end surface of the stopper member 19 contacts one end surface of the outer ring 17b of the ball bearing 17, and the other end surface of the outer ring 17b contacts the locking portion 1 of the body 10.
It is in contact with 1.

That is, the outer ring 17b of the ball bearing 17 is held between the locking part 11 of the body 10 and the stopper member 19 with a thrust applied in the axial direction by tightening the stopper member 19 to the sleeve part 14. There is. Thereby, the outer ring 17b of the ball bearing 17 is fixed to the body 10 in both the axial direction and the radial direction.
Note that the other configurations are the same as those of the first embodiment described above.

Therefore, in this third embodiment as well, the body 10
When subjected to vibration, the body 10, ball bearing 17, and throttle valve shaft 30 vibrate together in the axial and radial directions, and perform the same function as in the first embodiment. .

Fourth Embodiment In FIG. 7, which is an enlarged view of the portion corresponding to the bearing holding portion on the right side (accelerator lever 50 side) of FIG. Moreover, there is a gap of, for example, 5 to 40 μm in the radial direction and 50 to 40 μm in the axial direction between the ball 17c and the inner and outer rings 17a and 17b.
A minute distance of 200 μm is set.

A plurality of grooves (two grooves are shown in the figure) are formed in the circumferential direction on the outer periphery of the outer ring 17b of the ball bearing 17, and the grooves have a coefficient of thermal expansion equal to that of the aluminum body 10. A material having the same or similar value, such as resin 24, is integrally molded, and the outer circumferences of outer ring 17b and resin 24 have approximately the same diameter at room temperature (15 to 30°C). The material of the outer ring 17b is, for example, iron-based material such as bearing steel. The outer ring 17b of the body bearing 17 configured in this way is attached to the sleeve portion 1 of the body 10.
4 with a small press-fitting allowance (5 to 40 μm) until its inner end surface abuts against the locking portion 11 of the body 10. In other words, this fourth embodiment does not have the stopper member 19. Note that the other configurations are the same as those of the first embodiment described above.

Therefore, in this fourth embodiment as well, the body 10
When subjected to vibration, the body 10, ball bearing 17, and throttle valve shaft 30 vibrate together in the axial and radial directions, and perform the same function as in the first embodiment. .

By the way, the ball bearing 17 has an inner ring, an outer ring 17a,
17b is usually fixed to the shaft or to the sleeve. If both wheels 17a and 17b are press-fitted together, the diameter of the inner ring 17a will be increased,
Due to the reduction in the diameter of the outer ring 17b, the appropriate radial distance between the ball 17c and the inner and outer rings 17a and 17b changes significantly, and in the worst case, the ball 1
7c becomes unable to rotate. In addition, when fixed in the axial direction, due to axial deviation of the inner and outer rings 17a and 17b, the appropriate axial distance set between the ball 17c and the inner and outer rings 17a and 17b changes greatly, and in the worst case, the ball 17c becomes unable to rotate. In particular, when the body 10 is made of aluminum and the outer ring 17b is made of iron, the difference in thermal expansion is large.
The inner diameter of the outer ring 17b has a larger change than the outer diameter of the outer ring 17b, and there is a possibility that a gap may occur between the two. In order to prevent this, it is necessary to set a large press-fitting allowance for the outer ring 17b into the sleeve portion 14, but in that case, the above-mentioned problem is likely to occur.

However, according to the fourth embodiment, at high temperatures, the resin 24 integrally formed in the groove of the outer ring 17b expands to the same size as the sleeve part 14 of the body 10, so that the outer periphery of the outer ring 17b and the sleeve part 14 of the body 10 expand. The press-fit allowance with the inner periphery of is kept appropriate. Therefore, even at high temperatures, the body 10, ball bearing 17, and throttle valve shaft 30 vibrate together. In addition, since there is no need to consider changes in the press-fitting allowance due to temperature, the outer ring 17b and the body 10 can always be fixed even if the press-fitting allowance is set extremely small, and the press-fitting fixation of the inner and outer rings described above can be easily performed. This also solves the problem of rotational locking of the ball bearing.

In addition, a sealed bearing is used as the ball bearing 17, and the inner ring 17a is press-fitted into the throttle valve shaft 30, the outer ring 17b is press-fitted into the sleeve portion 14 of the body 10, and the outer periphery of the outer ring 17b is attached to the body 1.
Since the material is made of a material with a coefficient of thermal expansion equal to or close to 0, the press-fitting allowance is always maintained appropriately regardless of temperature changes, and the seal between the intake passage of the body 10 and the outside is ensured. Therefore, the oil seal 21 provided in the first to third embodiments described above can be eliminated.

<Effects of the invention> As described above, the present invention has the advantage that among the ball bearings that rotatably support both ends of the throttle valve shaft with respect to the body of the air control device, one of the ball bearings has an inner ring that is connected to the throttle valve shaft. While the outer ring is press-fitted onto the shaft and fixed, the outer ring is clamped between the locking part of the body and the stopper member with thrust applied via a spring or screw, or the outer ring has a thermal expansion coefficient that is the same as or approximates that of the body. By integrally forming a material with a coefficient of thermal expansion of a value of and press-fitting it into the body,
The outer ring is fixed in both the axial direction and the radial direction, so that when the air control device receives vibrations from the internal combustion engine, the body, ball bearing, and throttle valve shaft are fixed in the axial direction or radial direction of the throttle valve shaft. The three components vibrate in the radial direction, thereby preventing wear between the throttle valve shaft and the ball bearing, and between the ball bearing and the body. This also means that the distance between the throttle valve and the inner wall of the body is always maintained constant, which stabilizes the air control function and prevents wear between the throttle valve and the inner wall of the body as the throttle valve opens and closes. is also prevented.

Regarding the other ball bearing, there is a very small space between the inner ring and the throttle valve shaft, and between the outer ring and the body.
By providing this, it is easy to assemble the throttle valve shaft and the ball bearing to the body, and even if there is an error in the centering accuracy of the part of the body where the ball bearing is installed, this can be absorbed. This ensures that the throttle valve shaft is always properly supported by the ball bearing.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a vertical sectional view of the air control device, FIG. 2 is an enlarged vertical sectional view of a part of the right side of FIG. 1, and FIG. 4 is a view in the direction of arrow A in FIG. 1, FIG. 5 is a vertical sectional view showing the second embodiment, FIG. 6 is a vertical sectional view showing the third embodiment, and FIG. It is a longitudinal cross-sectional view showing a fourth example. 10... Body, 11... Locking part, 15... Spring, 16, 17... Ball bearing, 16a,
17a...Inner ring, 16b, 17b...Outer ring, 1
8, 19...stopper member, 30...throttle valve shaft,
32... Throttle valve, 42... Support, 44... Skrill.

Claims (1)

[Claims for Utility Model Registration] (1) In an air control device of the type in which a throttle shaft with a throttle valve attached to the body of the air control device is rotatably supported by ball bearings on both sides of the throttle valve. A support structure for a throttle valve, wherein the inner ring of one of the two ball bearings is press-fitted into the throttle valve shaft, the outer ring is pipe-fitted to the body, and the inner ring of the other ball bearing is connected to the throttle valve shaft. The outer rings are loosely fitted into the body, respectively, and both end surfaces of the outer ring in the ball bearing on the side where the inner ring is press-fitted into the throttle valve shaft are connected to a locking part formed on the body and a ring that is press-fitted into the body. The stopper member is clamped with a thrust applied in the axial direction by a spring disposed on the end face of the stopper member or by a stopper member fixed to the body via a screw, so that the inner ring is attached to the throttle valve shaft. A support structure for a throttle valve in an air control device, in which both end surfaces of an outer ring of a ball bearing that is interlocked are held between a locking portion formed in a body and a stopper member press-fitted into the body. (2) A support structure for a throttle valve in an air control device in which a throttle shaft with a throttle valve attached to the body of the air control device is rotatably supported by ball bearings on both sides of the throttle valve. The inner ring of one of the two ball bearings is press-fitted into the throttle valve shaft, and a material having a coefficient of thermal expansion that is the same as or similar to the material of the body is integrally formed in a groove portion formed on the outer peripheral surface. The outer ring is press-fitted into the body, the inner ring of the other ball bearing is fitted onto the throttle valve shaft, the outer ring is fitted onto the body, and both end surfaces of the outer ring are connected to the locking parts formed on the body, and the inner ring of the other ball bearing is fitted onto the throttle valve shaft. A support structure for a throttle valve in an air control device sandwiched between a stopper member and a stopper member.