JPH11166428A - Exhaust brake valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the difficulty of valve shaft rotation caused by rust generated in a housing and to reduce a surface pressure between a shaft and a bush. SOLUTION: A bearing part 18 and a sealing part 19 are provided in one bush 14 for supporting a valve shaft 22 to be freely rotated, seal rings 8a and 8b are arranged in the outer periphery of the valve shaft 22 so as to be housed in the sealing part 19, the diameter of a seal receiving part 24 sealed by the seal rings 8a and 8b is set smaller than that of the support receiving part 23 of the valve shaft 22 supported by the bush 14, and by serially arranging a plurality of seal rings 8a and 8b, a labyrinth seal 15 is formed. The thickness of the seal ring 8a having a large inner diameter among the plurality of seal rings 8a and 8b is set larger than that of the seal ring 8b having a small inner diameter, and both bushes 14 and 17 are protruded to the outside of the radial direction of a housing 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust brake valve disposed in a discharge passage of exhaust gas discharged from an engine of a vehicle or the like.

[0002]

FIG. 6 is a front view showing a conventional exhaust brake valve. This exhaust brake valve is provided in the middle of an exhaust pipe of an engine (not shown), and has a valve body 3 mounted on a valve shaft 2 rotatably supported by both cylindrical portions 1a and 1b of the housing 1.
And is supported by a bracket 4 attached to one end side, and is operated by an actuator (not shown),
The valve 3 is opened and closed by the rotation of a lever 5 attached to the outer end of the valve shaft 2.

A cylindrical housing 1 is provided with bearing cylinders 1a and 1b projecting along the diameter thereof.
Bushes 6 and 7 are arranged in a and 1b. A plurality of seal rings 8 are arranged in series on the outside of the bush 6 in one cylindrical portion 1a, and a mounting bracket 4 is arranged near the outside thereof. The plurality of seal rings 8 form a labyrinth seal 9. The other bush 7
A diamond-shaped cover 10 is arranged outside the box. The cover 10 is fixed to the cylindrical portion 1 b of the housing 1 by screwing two bolts 11, and the bush 7 is prevented from coming off by the cover 10.

[0004] As shown in FIG. 7, when the valve is closed,
The valve clearances C1 and C2 between the outer peripheral surface of the valve body 3 at the position farthest from the valve shaft 2 and the inner peripheral surface 1c of the cylindrical portion of the housing 1 are about 0.1 to 0.4 mm. Each of the thrust gaps C3 and C4 at both ends of the fixed portion is 0.
The dimensions were set to be 5 to 1.0 mm. This is to allow the valve element 3 to smoothly open and close over a long period of time in consideration of rust generated in the housing 1.

[0005]

In the case of such a conventional exhaust brake valve, a labyrinth seal 9 is provided outside one bush 6, and the bush 6 is rusted like stainless steel, aluminum alloy or copper alloy. Although the housing 1 is made of a cast iron which is apt to generate rust, the rust is generated in a portion near the outer periphery of the labyrinth seal 9 on the housing 1 side.
However, there is a problem that it is difficult to rotate smoothly. Also,
In the other bush 7, the cover 10 makes it difficult to lengthen the bush 7, the surface pressure between the valve shaft 2 and the bush 7 increases, the wear is remarkable, and there is a problem in durability. Was. Furthermore, since the gap and the thrust gap between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the valve element when the valve is closed are relatively large, there is a limit to the braking force during the operation of the exhaust brake.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to prevent the valve shaft from becoming difficult to rotate due to rust generated in a housing and to increase the length of a bush. Accordingly, it is an object of the present invention to provide an exhaust brake valve capable of reducing the surface pressure between the valve shaft and the bush and improving the braking force when the valve is closed.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention has a valve shaft having a valve body mounted in a discharge passage of exhaust gas discharged from an engine, and a housing having a valve shaft. In an exhaust brake valve in which the valve shaft is rotatably supported by a bush provided, the bush includes a bearing portion 18 and a seal portion, and is housed in the seal portion and a seal ring is provided on an outer periphery of the valve shaft. It is characterized by being arranged.

[0008]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side sectional view showing an exhaust brake valve according to an embodiment of the present invention.
FIG. 3 is a partially enlarged cross-sectional view showing one side portion thereof in an enlarged manner. This exhaust brake valve supports a valve shaft 22 with both bushes 14 and 17 provided on a housing 1, and has a bearing portion 18 and a seal portion 19 on one bush 14. Seal ring 8 on the outer periphery of shaft 22
a, 8b, and the valve shaft 22 supported by the bush 14
The diameter of the seal receiving portion 24 sealed by the seal rings 8a and 8b is made smaller than the diameter of the support receiving portion 23 of FIG.
The labyrinth seal 15 is formed by arranging a plurality of seal rings 8a and 8b in series.

In the exhaust brake valve, the thickness of the thick seal ring 8a having a large inner diameter in the plurality of seal rings 8a and 8b is made larger than the thickness of the thin seal ring 8b having a small inner diameter, and the sealing portion of the bush 14 is formed. 19 is the cylinder 1
a protruding portion 21 protruding outward is also provided on the other bush 17, and the cover 29 is provided with an engaging hole 29 a into which the protruding portion 21 is fitted, and supports the valve shaft 22. The supporting length of the bush 17 can be increased. The exhaust brake valve rotates the valve shaft 22 by the operation of the actuator 30 via the lever 5 attached to the protruding end 25 of the valve shaft 22 to open and close the valve body 3, and exhausts when the valve is closed. The brakes work.

The housing 1 has integrally formed two cylindrical portions 1a and 1b protruding from the cylindrical housing main body 12 in an extension of the diameter thereof, and each of the cylindrical portions 1a and 1b has a bush 14, 14 respectively.
17 is press-fitted, rotatably supports the valve shaft 22 via these bushes 14, 17, and is disposed in the middle of a discharge passage of exhaust gas discharged from the engine.

The housing 1 includes one bush 1.
A hat-shaped cover 28 for covering the outer end of the cover 4 and a flat cover 29 for retaining the other bush 17 are attached, and are supported by the attachment bracket 4 fixed to one side.

Further, in the housing 1, a corrosion-resistant metal layer 12a having excellent corrosion resistance is formed on the entire inner peripheral surface of the cylindrical housing body 12, and as shown in FIG. The dimensions are set such that the gaps C1 and C2 are in the range of 0 to 0.1 mm so that the outer peripheral surface of the valve body 3 at the position farthest from the valve shaft 22 can contact the corrosion-resistant metal layer 12a on the inner peripheral surface. The thrust clearance C3 shown in FIG.
The dimensions are set so that the thrust gap similar to C4 is 0.1 to 0.3 mm (0.2 mm on average). The corrosion-resistant metal layer 12a is made of stainless steel by gas at 2000 ° C. to 300 ° C.
It is made into a high temperature liquid of 0 ° C. and sprayed on the entire inner peripheral surface of the housing main body 12 by plasma welding means to form a rustproof layer.

As shown in FIG. 2, one bush 14 has a bearing 18 fitted into the cylindrical portion 1a of the housing 1.
And the seal portion 19 integrally protruding outside of the cylindrical portion 1a and the bracket 4, the outer diameter of the seal portion 19 is smaller than the outer diameter of the bearing portion 18, and the housing hole 19a of the seal portion 19 is formed. The inner diameter is set to be larger than the inner diameter of the bearing hole 18 a of the bearing 18, and the outer circumference of the bearing 18 and the seal 19
Of the cover 28 on the stepped surface 14a between
8a is abutted to prevent it from falling off. Bearing hole 18a
Extends to the outside of the outer end surface of the cylindrical portion 1a of the housing 1.

The bush 14 has a stepped surface 14b formed between the bearing hole 18a and the housing hole 19a. The distance between the stepped surface 14b and the small stepped surface 22a of the valve shaft 22 is determined by the distance between the steps. The dimensions are set to be sufficiently large with respect to the gap C from the end face to the large step surface 22b of the valve shaft 22, and a plurality of seal rings 8a, 8b forming the labyrinth seal 15 are accommodated in the seal portion 19. I have. The bushing 14 moves in the axial direction by an amount corresponding to the gap C along with the rotation of the valve shaft 22 so that the sliding contact surface with the outer peripheral surface of the valve shaft 22 moves. It contacts the outer peripheral surface of the valve shaft 22 from the surface 22b to the small step surface 22a.

The labyrinth seal 15 is configured by alternately arranging thick seal rings 8a having a larger diameter and thin seal rings 8b having a smaller diameter. The thick seal ring 8 a has a large gap between its inner periphery and the outer periphery of the valve shaft 22 so that a small gap is formed between its outer peripheral surface and the inner peripheral surface of the seal portion 19 of the bush 14. Dimensions are set. The thin seal ring 8 b is dimensioned such that its inner peripheral surface forms a small gap with the outer peripheral surface of the valve shaft 22.

In the labyrinth seal 15, a gas expansion chamber 31 is formed by the inner peripheral surface of the thick seal ring 8a, the end surface of the thin seal ring 8b on both sides thereof, and the outer peripheral surface of the valve shaft 22. In this expansion chamber 31, three chambers are arranged here in series, and a vortex is generated in the inflowing exhaust gas to reduce the flow velocity of the exhaust gas, and the exhaust gas leaks to the outside through the labyrinth seal 15. It is for suppressing that. In addition, in this expansion chamber 31,
High temperature grease (TiO ₂ ,
MoS ₂ , graphite) to prevent the exhaust gas from leaking.

As shown in FIG. 3, the other bush 17 is fitted into the cylindrical portion 1b of the housing 1 and has a larger outer diameter and a larger-diameter bearing portion 20 and a smaller outer diameter protruding from the cylindrical portion 1b. Small-diameter projection 21 and closing plate 21 for closing the outer end
a in the bearing hole 17a having a constant inner diameter.
The second support receiving portion 27 is fitted so as to rotatably support the end of the valve shaft 22, and the small-diameter projecting portion 21 is fitted into the engaging hole 29 a of the cover 29. The bearing hole 17a extends to the inside of the small-diameter projection 21. And the bush 17
The cover 29, which is attached by screwing a bolt 33 to the rhombic end surface of the cylindrical portion 1b of the housing 1, is brought into contact with the end surface 20a of the large-diameter bearing portion 20 to prevent it from falling off.
The inner peripheral surfaces of the bushes 14 and 17 are coated with high-temperature grease (Ti
O ₂ , MoS ₂ , and graphite) are applied.

The valve shaft 22 has a support receiving portion 23 rotatably supported by the bearing portion 18 of the one bush 14 and the small step surface 2.
A space for accommodating the labyrinth seal 15 between the outer periphery of the seal receiving portion 24 and the inner periphery of the seal portion 19 of the bush 14 is integrally provided with a small-diameter seal receiving portion 24 following this via the 2a. The lever 5 is attached by tightening a nut 34 screwed into the male screw 25a of the protruding end 25. The lever 5 rotates by the operation of the attached actuator 30.

The valve shaft 22 integrally has an intermediate portion 26 to which the valve element 3 is mounted, and a support receiving portion 27 rotatably supported by the large-diameter bearing portion 20 of the other bush 17. Screw holes 26a opened in the middle part 26 at intervals in the axial direction
A circular butterfly valve element 3 is attached by screwing a bolt 36 into the valve body.

In the exhaust brake valve according to the above-described embodiment of the present invention, when the actuator 30 is not operated, as shown in FIG. Lever 5 when activated
, The valve shaft 3 is rotated, and the valve body 3 is closed as shown in FIG. 6 with a slight gap left between the outer peripheral surface and the inner peripheral surface of the housing 1. Works.
When the action of the exhaust brake is unnecessary, the exhaust brake valve returns to the open state shown in FIG.

In such an exhaust brake valve, the axial length of the bearing hole 18a of the bearing portion 18 in the one bush 14 and the bearing hole 17a of the other bush 17 can be increased. Since the pressure can be reduced and high temperature grease is applied to the bearing holes 17a and 18a, wear of the bushes 14, 17 and the valve shaft 22 can be suppressed. Even if the mutual contact surface with the valve shaft 22 is worn, the seal receiving portion 24 does not wear, so that there is an advantage that exhaust gas leakage can be reduced.

The valve shaft 22 has a small step surface 22 on one end side.
Since the seal receiving portion 24 has a small diameter through a, and a plurality of seal rings 8a and 8b are disposed on the outer periphery of the seal receiving portion 24, the outer diameter of the valve shaft 22 is reduced by the reduced diameter. Since the clearance area with the inner peripheral surface of the thin seal ring 8b is reduced, the exhaust gas leakage is reduced, and even if the exhaust gas leaks, the sealing portion 19 of the bush 14 protrudes to the outside of the bracket 4, so that Since the leaked exhaust gas is kept away from the bracket 4, there is also an advantage that contamination is prevented.

The present invention is not limited to the above embodiment, and various modifications and changes can be made. For example, as shown in FIG. 5, it is also possible to accommodate the entire one bush 14 having no protruding portion in the corresponding tubular portion 1a of the housing 1 and make the other bush 17 the same as the conventional one, thereby achieving miniaturization. The one bush 14 and the labyrinth seal 15 may be the same as in FIG. 1 and the other bush 17 may be the same as the conventional bush. On the contrary, the one bush 14 is the same as the conventional bush and the other bush 17 is shown in FIG. It may be the same as the one. Further, the corrosion-resistant metal layer 12a may be formed of an alloy having excellent corrosion resistance other than stainless steel.

[0024]

According to the present invention, a valve shaft is rotatably supported by a bush provided in a housing, and the bush is provided with a bearing portion and a seal portion. By arranging the seal ring, the seal ring is prevented from being fixed by rust generated in the housing,
It is possible to reliably prevent the valve shaft from becoming difficult to rotate,
There is no change over time, and the effect of improving durability is achieved. Also, by making the diameter of the seal receiving portion sealed by the seal ring smaller than the diameter of the support receiving portion of the valve shaft supported by the bush, the clearance area along the outer periphery of the valve shaft in the seal receiving portion is reduced. The seal ring is arranged in series to form a labyrinth seal, and the thickness of the seal ring having a large inner diameter among the plurality of seal rings is reduced by the thickness of the seal ring having a small inner diameter. By setting it larger than that, it is possible to further reduce leakage of exhaust gas. Furthermore, by protruding the seal portion of the bush to the outside of the housing, the length of the bush is lengthened to reduce the surface pressure between the shaft and the bush,
Therefore, durability can be improved by reducing wear,
An outwardly protruding protruding portion is provided on the bush, an engaging hole into which the protruding portion is fitted is provided on the cover, and the support length of the bush supporting the valve shaft can be increased. The surface pressure with the bush can be reduced. And
By forming a corrosion-resistant metal layer with excellent corrosion resistance on the inner peripheral surface of the housing, by allowing the outer peripheral surface of the valve body to be in contact with the corrosion-resistant metal layer at a position away from the valve shaft when the valve body is closed, The braking force at the time of closing the valve is improved, and the hardness of the inner surface of the housing can be increased.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an exhaust brake valve according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing one side of the exhaust brake valve of FIG. 1 in an enlarged manner.

FIG. 3 is a partially enlarged cross-sectional view showing the other side of the exhaust brake valve of FIG. 1 in an enlarged manner.

FIG. 4 is a cross-sectional view taken along a plane perpendicular to the valve shaft, showing a closed state of the exhaust brake valve according to the embodiment of the present invention.

FIG. 5 is a side sectional view showing a modified example of the exhaust brake valve of FIG.

FIG. 6 is a front view showing a conventional exhaust brake valve.

FIG. 7 is an exaggerated front view of a gap between an inner surface of a housing and a valve body when a conventional exhaust brake valve is in a closed state.

[Explanation of symbols]

 C gap C1, C2 Valve gap 1 Housing 3 Valve 4 Bracket 8a, 8b Seal ring 12 Housing main body 12a Corrosion-resistant metal layer 14 Bush 15 Labyrinth seal 17 Bush 18 Bearing part 19 Seal part 21 Projection part 22 Valve shaft 23 Support receiving part 24 Seal receiving part 28, 29 Cover 29a Engagement hole

Continued on the front page (72) Inventor Masahiro Kaneko 2-11-6 Shinmeicho, Higashimatsuyama-shi, Saitama Automobile Equipment Co., Ltd. Matsuyama Plant (72) Inventor Shuichiro Aoyagi 2-1-16-1 Shinmeicho, Higashimatsuyama-shi, Saitama Inside the Matsuyama Plant of Automotive Equipment Co., Ltd.

Claims (6)

[Claims] 1. An exhaust system having a valve shaft having a valve body mounted in a discharge passage of exhaust gas discharged from an engine, wherein the valve shaft is rotatably supported by a bush provided in a housing. An exhaust brake valve according to a brake valve, wherein the bush includes a bearing portion and a seal portion, and a seal ring is provided on the outer periphery of the valve shaft so as to be accommodated in the seal portion. 2. A diameter of a seal receiving portion sealed by the seal ring is smaller than a diameter of a support receiving portion of the valve shaft supported by the bush.
The exhaust brake valve as described in the above. 3. A method of forming a labyrinth seal by arranging a plurality of said seal rings in series, wherein a thickness of a seal ring having a large inner diameter in the plurality of seal rings is larger than a thickness of a seal ring having a small inner diameter. The exhaust brake valve according to claim 1 or claim 2, wherein 4. The exhaust brake valve according to claim 1, wherein the seal portion of the bush protrudes to the outside of the housing. 5. A valve shaft provided with a valve disposed in a discharge passage of exhaust gas discharged from an engine, wherein the valve shaft is rotatably supported by a bush provided in a housing, In an exhaust brake valve including a cover that covers an outer end surface of the bush, the bush has an extending protrusion that protrudes outward, and the cover has an engagement hole into which the protrusion is fitted, An exhaust brake valve, wherein a supporting length of the bush for supporting a valve shaft can be increased. 6. An exhaust system having a valve shaft having a valve body mounted in a discharge passage of exhaust gas discharged from an engine, wherein the valve shaft is rotatably supported by a bush provided in a housing. In the brake valve, a corrosion-resistant metal layer having excellent corrosion resistance is formed on an inner peripheral surface of the housing, and the outer peripheral surface of the valve body at a position away from the valve shaft when the valve body is in a closed state is formed of the corrosion-resistant metal layer. Exhaust brake valve characterized in that it can contact with the vehicle.