JPS6111473Y2 - - Google Patents

Description

[Detailed description of the invention] The invention relates to an air control device equipped with a supercharger.
In particular, the present invention relates to an air leak prevention structure in a throttle valve bearing portion of an air control device.

The flow rate of air that is pumped from the turbocharger and supplied to the engine is controlled by the opening degree of the throttle valve, but since the shaft to which this throttle valve is attached penetrates the wall of the air flow path, the bearing part is It is necessary to have a structure that prevents leakage.

FIG. 1 is a sectional view of a conventional air control device.
This air control device 1 is provided downstream of a supercharger 2 and includes an intake passage 3, a throttle valve 4, and an idle adjustment screw 13. This idle adjustment screw 13 is used to adjust the amount of air flowing from the detour passage 11 to the outlet 12 during idling operation when the opening degree of the throttle valve 4 is small. The opening degree of the throttle valve 4 is adjusted by rotating a throttle valve shaft 5 that passes through the wall of the intake passage 3 of the air control device 1, thereby controlling the amount of air taken into the engine. The engine is connected to the lower part of the air control device 1 via an intake pipe, and operates by sucking in a mixture of air and fuel injected from a fuel injection valve provided in the intake pipe.

FIG. 2 is an enlarged sectional view showing the bearing structure of the throttle valve shaft in FIG. 1, and the same parts as in FIG. 1 are given the same reference numerals. Throttle valve shaft 5 to which throttle valve 4 is screwed
is rotatably supported by a bearing portion 9 via a ball bearing 6, and the ball bearing 6 is stored in a bearing storage portion 9A of the bearing portion 9. The ball bearing 6 is fixed by a bushing 8 driven into the retaining portion 9B of the bearing portion 9, and is made of an elastic material with an annular groove formed between the inner surface of the bushing 8 and the throttle valve shaft 5. Seal member 1
Inserting 0. Note that grease sealing plates 7 are installed on both sides of the balls of the ball bearing 6. This type of bearing structure was proposed in Japanese Patent Application No. 54-80157.
It has been proposed as a number.

With the bearing structure configured in this manner, when the driver depresses the pedal, the throttle valve shaft 5 supported by the ball bearing 6 smoothly rotates to change the opening degree of the throttle valve 4. However, since air pressurized by the compressor 3 is flowing inside the air control device 1, air leaks from the gap between the ball bearing 6 and the throttle valve shaft 5, pushing the sealing member 10 outward. . In particular, since high-pressure air is being pumped during high-load operation of the engine, the sealing member 10, which is an elastic body, is deformed to enlarge the gap and leak a large amount of air.

Generally, in the case of an air control device equipped with a fuel injection valve, the air flow meter installed upstream of the air control device 1 detects the amount of air, and this detection signal is sent to a computer to perform predetermined calculations to control the fuel injection valve. The fuel supply valve is controlled by adjusting the opening time ratio of the solenoid valve. Therefore, leakage of intake air from the throttle valve bearing of the air control device disturbs the air-fuel ratio of the air-fuel mixture, causing the engine to run poorly and deteriorating the exhaust composition, resulting in wasted fuel.

Conventionally, the following measures have been taken to prevent this air leakage. One of them is the seal member 10
It is made of hard rubber to prevent deformation.
However, in this case, the friction with the throttle valve shaft 5 becomes large, making the opening/closing operation of the throttle valve 4 unsmooth.
Once the sealing member 10 wears out, a disadvantage arises in that the amount of leaked air increases. As another measure, a sealing member as shown in cross section in FIG. 3 has been used. This sealing member is made of soft rubber and has a metal ring 14 embedded in the outer cylindrical portion to provide rigidity. That is, the outer surface of the outer cylindrical portion improves the adhesion with the bush 8, and the inner annular protrusion improves the sealing performance of the throttle valve shaft 5. However, when the bearing portion 9 is heated by the air compressed by the compressor 3 and whose temperature has increased, the sealing member 10 is further softened and the inner annular protrusion is pushed out. Therefore, the seal member 1
Although the outer peripheral surface of the valve 0 and the bush 8 are in close contact with each other, the gap between the throttle valve shaft 5 and the seal member 10 is large.
If the deformation of the metal ring 14 is severe, the rubber coating is torn and the metal ring 14 is exposed. That is, the sealing member 10 has a short lifespan and must be replaced frequently.

On the other hand, as a bearing structure for the exhaust brake valve,
As seen in Japanese Patent No. 54-168424, a system was proposed in which a plane bearing was arranged around the rotating shaft, a gasket was located on the opposite side of the valve body, and this gasket was prevented from coming off with a bolted plate. ing.

However, this structure requires a gasket to be placed between the plain bearing and the retaining plate, which can cause the plain bearing to move due to expansion and contraction of the gasket, and
There is also a problem that the plate must be secured by bolts, which is undesirable from the standpoint of assembly work.

The present invention eliminates the above-mentioned problems of the conventional technology,
It is an object of the present invention to provide a throttle valve bearing structure for an air control device suitable for maintaining good sealing performance for a long period of time.

Its characteristics are: (a) a bearing part formed on the wall of the intake passage connected downstream of the supercharger; (b) a bearing housing part formed in the bearing part and a bearing housing part formed further outside of this bearing part; (c) a bearing housed in the bearing housing; (d) a throttle valve shaft that extends outward through the inside of the bearing; (e) a throttle valve shaft that extends outward through the bearing; (f) a sealing member into which the throttle valve shaft is inserted; (f) fixedly disposed within the retaining housing;
The bearing structure includes an annular body having a retaining portion that prevents the bearing from slipping out of the bearing storage portion and a holding portion that prevents the sealing material from being pushed out by the internal pressure of the intake passage.

The present invention will be explained below with reference to the drawings.

FIG. 4 is a sectional view showing a bearing structure according to an embodiment of the present invention. The bush 15 used for this purpose has a small diameter part 15A with a reduced inner diameter and a large diameter part 15B formed on the outer end surface of an annular metal body. After inserting the sealing member 10 having a soft V-shaped annular groove similar to the conventional one, if the bushing 15 is driven into the open end of the retaining storage part 9B of the bearing part 9, the small diameter part 15A of the bushing 15 will release the sealing member 10. The outer circumference of the sealing member 10 is held down and the outer circumferential surface of the sealing member 10 is surrounded. Therefore, this small diameter portion 15A forms a holding portion that suppresses deformation of the inner annular side of the seal member 10 and reduces the gap with the throttle valve shaft 5, making it possible to prevent air leakage over a long period of time. becomes.

The bearing structure of this embodiment suppresses deformation of the seal member and improves the sealing performance of the throttle valve shaft for a long period of time by driving a bush into the bearing portion that surrounds the outer side of the seal member. It has this effect.

Furthermore, in the bearing structure of this embodiment, the large diameter portion 15B of the bush 15 comes into contact with the end surface of the ball bearing 6 to form a retaining portion, so movement of the ball bearing 6 is prevented and good bearing action is maintained. Moreover, since the bushing 15 is simply driven in, the assembly work is easy.

FIG. 5 is a sectional view showing a bearing structure according to another embodiment of the present invention. In this case, an annular metal body 18 having a bent portion 18A with one end bent into an L-shaped cross section is inserted into the bearing portion 9, and then the sealing member 10 is fitted into the throttle valve shaft 5. Since a thin layer of adhesive is applied between the bearing part 9, the metal body 18, and the seal member 10 to fix the seal member 10, the outer circumference of the seal member 10 is securely fixed to the bearing part 9 via the metal body 18. There is. Therefore, the portion of the metal body 18 to which the sealing member 10 is fixed forms a holding portion, and thereby the sealing member 10 is fixed.
The inner protrusion ensures airtightness with the throttle valve shaft 5 and is not pushed out by internal pressure.

The bearing structure of this embodiment suppresses deformation of the seal member by bonding a metal tube to the bearing portion and bonding the outer circumferential portion of the seal member to the inner surface of the metal tube. It has the effect of maintaining good sealing performance for a long period of time.

Furthermore, in the case of this embodiment as well, the bent portion 18A
contacts the end face of the plain bearing 17 to form a retaining portion, preventing movement of the plain bearing 17 and maintaining good bearing action.In addition, since only the metal tube is inserted, assembly is easy. This makes the work easier.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional air control device, Fig. 2 is an enlarged sectional view showing the bearing structure of the throttle valve shaft in Fig. 1, Fig. 3 is an enlarged sectional view of the second seal member, and Fig. 4. FIG. 5 is a cross-sectional view showing a bearing structure according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view showing a bearing structure according to another embodiment of the present invention. 1... Air control device, 2... Supercharger, 3... Compressor, 4... Throttle valve, 5... Throttle valve shaft, 6
... Ball bearing, 7 ... Grease sealing plate,
15... Button, 9... Bearing part, 10... Seal member, 13... Idle adjustment screw, 17...
Plain bearing, 18...metal tube.

Claims (1)

[Claims for Utility Model Registration] (a) A bearing portion formed in the wall of the intake passage connected downstream of the supercharger; (b) A bearing storage portion formed in the bearing portion and further outside thereof (c) a bearing stored in the bearing housing; (d) a throttle valve shaft that extends outward through the bearing; (e) arranged in the retaining housing. (f) a sealing member fixedly disposed within the retaining housing, into which the throttle valve shaft is inserted;
A throttle valve bearing structure including an annular body having a retaining part that prevents the bearing from coming out of the bearing storage part and a holding part that prevents the sealing material from being pushed out by the internal pressure of the intake passage.