JP3362342B2 - Air control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air control device for supplying air to an internal combustion engine or the like.

[0002]

2. Description of the Related Art In an engine equipped with a fuel injection system, normally, intake air is not warmed but the outside air is taken in as it is. Therefore, when traveling in a cold region, cold outside air enters the suction passage as it is, so that freezing occurs near the throttle valve, and this phenomenon is remarkable especially when traveling on a waterway or a snowy road. Even in an engine that employs an EGR (exhaust gas re-combustion) system, freezing is likely to occur due to water vapor in the exhaust gas that is introduced near the throttle valve. Therefore, conventionally, engine cooling water is circulated around the throttle body to heat the throttle body and prevent freezing in the intake passage.

[0003]

However, in fact, even in a portion other than the inside of the intake passage, such as a throttle shaft and a return spring protruding from the intake passage, freezing may occur due to water intruding from the outside. However, the conventional device is not configured to sufficiently heat the outside of such an intake passage, and thus is insufficient to prevent the throttle shaft, the return spring, and the like from freezing.

The present invention solves this problem by providing an air control device which can prevent not only freezing near the throttle valve inside the intake passage but also freezing around the throttle shaft outside the intake passage and its vicinity. The purpose is to get.

[0005]

SUMMARY OF THE INVENTION An air control device according to the present invention includes a throttle body having a pair of holes which are opened in an intake passage and are opposed to each other, and a part of the intake passage which is incorporated in the throttle body. A cylindrical member having a shaft support portion, a throttle shaft rotatably supported by the shaft support portion, a throttle valve attached to the throttle shaft for changing a flow passage area of the intake passage, and the cylinder And a means for heating the cylindrical member, wherein the shaft support portion projects from the hole to the outside of the throttle body.

[0006]

The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a diagram showing a configuration of an air control device according to an embodiment of the present invention, and FIG. 2 is a perspective view of a cylindrical member.

The throttle body 12 has an intake passage 16 defined by an inner wall 14, and the flow passage area of the intake passage 16 changes depending on the opening of the throttle valve 32.
As a result, the amount of air passing through the intake passage 16 is adjusted. The throttle valve 32 is attached to the throttle shaft 30. A throttle lever 36 is fixed to a protruding portion of the throttle shaft 30 from the throttle body 12, and a return spring including an inner spring 40 and an outer spring 42 is provided. Has been. The return spring biases the throttle valve 32 toward the fully closed position. Therefore, the throttle lever 36 rotates in conjunction with an accelerator mechanism (not shown), whereby the throttle valve 32 is set to a predetermined opening, and when the accelerator mechanism is opened, the throttle valve 32 is moved to the fully closed position by the action of the return spring. Will be returned.

The cylindrical member 20 has a cylindrical portion 22 and a pair of cylindrical shaft supporting portions 25 and 26 extending in the opposite direction from the outer peripheral surface 23 of the cylindrical portion 22. Cylindrical part 2
2 has a hole 29, and an outer peripheral surface 23 of the cylindrical portion 22.
A plurality of protrusions 23a extending in the circumferential direction are formed in parallel with each other. Grooves 23b are formed between the adjacent protrusions 23a, so that the outer peripheral surface 23 has irregularities. The shaft support portions 25 and 26 are open to the hole 29 at their base ends.

It is desirable that the cylindrical member 20 is formed of a material having good thermal conductivity, such as metal. On the other hand, the throttle body 12 is preferably made of resin in order to reduce weight and fuel consumption, but may be made of metal.

The throttle body 12 is formed with a pair of holes 17 and 18 facing each other.
One end of 8 is open to the intake passage 16. Cylindrical member 2
0 indicates the throttle body 12 at the positions of the holes 17 and 18.
The hole 29 has substantially the same diameter as the inner wall 14 of the throttle body 12, and constitutes a part of the intake passage 16. The shaft support portions 25 and 26 have holes 1 respectively.
It extends through 7 and 18 and projects to the outside of the throttle body 12.

The throttle shaft 30 extends through the hole 29 and the insides of the shaft supporting portions 25 and 26, and projects outward from the tip of the shaft supporting portion 25. The throttle shaft 30 is supported by shaft support portions 25 and 26 so as to be rotatable around its axis. Bushings 38 and 39 are press-fitted between the throttle shaft 30 and the shaft support portions 25 and 26. Bushings 38 and 39 have
For example, the outer surface is made of a metal having a good heat transfer property, and the inner surface is coated with a thin resin.

A cap 44 is attached to the protruding portion of the throttle shaft 30 from the shaft supporting portion 25. The cap 44 has a cylindrical bearing portion 45 and an annular portion 46 located on the outer peripheral side of the bearing portion 45. The throttle shaft 30 is fitted on the inner surface of the bearing portion 45, and the tip of the bearing portion 45 is in contact with the bush 38. As a result, the throttle body 1 of the throttle shaft 30
The protruding portion from 2 is covered by the shaft supporting portion 25, the bush 38, and the bearing portion 45. The annular portion 46 extends in the longitudinal direction of the throttle shaft 30, and a minute gap is formed between the tip of the annular portion 46 and the throttle body 12.

The inner spring 40 and the outer spring 42 are coil springs, extend in the longitudinal direction of the throttle shaft 30, and are supported by the cap 44 and the throttle body 12 at both ends.
The inner spring 40 is provided between the bearing portion 45 and the annular portion 46 and covers the entire outer periphery of the shaft support portion 25. The outer spring 42 is provided outside the annular portion 46 and covers the entire outer periphery of the annular portion 46.

FIG. 3 is a sectional view taken along the line III--III in FIG. 1 when cut in the horizontal direction, and FIG. 4 is a view of the apparatus of this embodiment mounted on an actual engine as seen from above.

The hot water portion 50 is formed on the throttle body 12 and is in contact with the outer peripheral surface 23 of the cylindrical portion 22. Hot water part 5
0 is formed at a position apart from the shaft support portions 25 and 26, and the contact area with the outer peripheral surface 23 is, for example, about 20% of the area of the entire outer peripheral surface 23. An inlet passage 52 and an outlet passage 54 are connected to the hot water portion 50, and the inlet passage 52 and the outlet passage 54 are part of a circulation passage for engine cooling water. That is, in the apparatus of this embodiment, engine cooling water is used as hot water. The engine cooling water is guided from the inlet passage 52 to the hot water portion 50 by the action of a water pump (not shown), and is discharged from the outlet passage 54.

The operation of this embodiment will be described. Cylindrical member 2
Zero is heated by the engine cooling water in the hot water section 50. Since the contact area between the engine cooling water and the outer peripheral surface 23 is large due to the unevenness formed on the outer peripheral surface 23, the cylindrical portion 22 is effectively heated. Further, the cylindrical portion 22 and the shaft supporting portions 25 and 26 are integrally formed of metal or the like having a high heat transfer property, so that the heat can be smoothly transferred from the cylindrical portion 22 to the shaft supporting portions 25 and 26.

The heat transferred to the shaft support portions 25 and 26 is transferred to the throttle shaft 30 via the bushes 38 and 39, and further transferred to the throttle valve 32.
Therefore, the throttle shaft 30 and the throttle valve 32 are prevented from freezing.

Further, the heat of the shaft supporting portion 25 is generated by the bush 3
It is transmitted from the bearing portion 45 to the cap 44 via the shaft 8.
The heat of the cap 44 is transmitted from the bearing portion 45 to the throttle shaft 30 and the inner spring 40, and from the annular portion 46 to the inner spring 40 and the outer spring 42. Therefore, the inner spring 40 is warmed by the shaft support portion 25, the bearing portion 45, and the annular portion 46, and the outer spring 42 is warmed by the annular portion 46.

As described above, according to the present embodiment, the protruding portions of the throttle valve 32 and the shaft support portion 25 from the throttle body 12 where freezing easily occurs are effectively heated. Therefore, the throttle valve 32, the throttle shaft 30, the inner spring 40, and the outer spring 42 are prevented from freezing, and the opening / closing operation of the throttle valve 32 can always be performed smoothly.

In the apparatus of this embodiment, the cylindrical portion 22 and the shaft supporting portion 26 have an integral structure, but the invention is not limited to this, and they may be formed by separate members.

[0021]

As described above, according to the present invention, it is possible to prevent not only freezing in the vicinity of the throttle valve inside the intake passage but also freezing in the throttle shaft outside the intake passage and its vicinity at the same time. .

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an air control device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a supporting member provided in the air control device shown in FIG.

FIG. 3 is a cross-sectional view of the air control device of FIG. 1 taken along the line III-III.

FIG. 4 is a top view of the air control device of FIG. 1.

[Explanation of symbols]

12 Throttle body 16 Intake passage 17, 18 holes 20 Cylindrical member 23 outer peripheral surface 25, 26 Shaft support 30 throttle shaft 32 Throttle valve

Continuation of the front page (56) References JP-A-3-941 (JP, A) JP-A-2-91431 (JP, A) JP-A-59-165835 (JP, A) Jitsukaihei 3-17241 (JP , U) Actually open 58-53845 (JP, U) Actually open 5-50058 (JP, U) Actually open 4-119338 (JP, U) Actually open 53-20589 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02M 15/02 F02M 35/10 F02D 9/02 F02D 9/10

Claims (4)

(57) [Claims] 1. A throttle body having a pair of holes that are open to an intake passage and face each other, and a cylindrical member that is incorporated in the throttle body to form a part of the intake passage and that has a shaft support portion. A shaft that is rotatably supported by the shaft support portion; a throttle valve that is attached to the throttle shaft to change a flow passage area of the intake passage; and a unit that heats the cylindrical member. An air control device, wherein a support portion projects from the hole to the outside of the throttle body. 2. The air control device according to claim 1, wherein irregularities are formed on an outer peripheral surface of the cylindrical member. 3. The air control device according to claim 1, wherein the cylindrical member is made of metal. 4. The air control device according to claim 1, wherein the throttle body is made of resin.