JP2510217Y2 - Exhaust brake seal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an exhaust brake seal device, and more particularly to an exhaust brake seal device with improved valve drive means.

[Conventional technology]

In large vehicles such as trucks and buses, it is well known that, in addition to the normal foot brake, an exhaust brake that closes the exhaust pipe and uses the increase in compression resistance of the piston to obtain a braking force is also provided.

The exhaust brake device normally penetrates one bearing of a valve shaft of a butterfly valve arranged in the exhaust pipe to extend out of the pipe, and operates the valve shaft to rotate the butterfly valve.
Therefore, during operation of the exhaust brake, the upstream side of the butterfly valve has high temperature and high pressure, so that gas leakage easily occurs from the bearing portion, and the braking force of the exhaust brake is reduced. As described above, since high temperature and high pressure act on the exhaust brake, it is not possible to employ a normal sealing means used at normal temperature and low pressure.

Therefore, various sealing means have been conventionally proposed. For example, in Japanese Utility Model Laid-Open No. 60-39744, a seal portion of a valve shaft of a butterfly valve penetrating a bearing is provided with a means for generating a seal pressure by a high pressure generated by an operation of an exhaust brake. That is, the means disclosed in this publication is
A seal chamber is formed in two stages on the outer valve shaft of the bearing, and a flange-shaped member attached to the valve shaft is arranged in each seal chamber. And a seal member is arranged on the butterfly valve side of each flange-shaped member.

When the exhaust brake of the publication is actuated and the butterfly valve is closed, the valve-side flange-like member is biased toward the seal member side by the high-pressure exhaust gas, so that both flange-like members act as seal members. Generates a sealing force by pressing. Therefore, the sealing means of the exhaust brake of the above publication can generate a higher sealing force as the exhaust gas pressure becomes higher.

[Problems to be solved by the device]

By the way, in the sealing force generating means described in the above publication, as described above, the two-stage sealing means are attached to the valve shaft so as to be spaced apart from each other, and are configured to press and seal the sealing members respectively. Therefore, if the sealing member is a soft one such as an elastic material, it is possible to press the two sealing members for sealing. However,
The exhaust brake has high temperature and high pressure, and it is not possible to use a compressible elastic material such as rubber. Therefore, it is necessary to use, as the seal member, one having a high hardness such as a metal elastic body that can withstand high temperatures.

An elastic material having a high hardness such as metal is used for the seal member, a seal chamber penetrating the valve shaft is formed in two stages, and a flange-shaped member is attached to the valve shaft for each seal chamber. Forming by pressing has a problem that the actual structure becomes extremely complicated, neither manufacturing nor maintenance is easy, and there is a cost disadvantage.

The present invention has been made in view of the above problems, and when the sealing material is pressed against the sealing surface to seal by using the exhaust gas pressure that becomes high due to the operation of the exhaust brake, the structure is An object of the present invention is to provide an exhaust brake seal device that is simple, has a small number of parts, and is easy to maintain.

[Means for solving the problem]

In order to achieve the above object, the structure of the exhaust brake sealing device of the present invention comprises a cylindrical sealing surface provided coaxially with the valve shaft at a penetrating portion where the valve shaft of the butterfly valve penetrates the exhaust brake main body. A ring groove-shaped seal chamber that opens toward the cylindrical seal surface is formed facing the cylindrical seal surface, and the seal chamber-side seal surface is formed on the axial wall outer wall side of the seal chamber. Then, a ring-shaped seal member, which is freely expandable and contractible, is slidably in contact with both the cylindrical seal surface and the seal chamber side seal surface is fitted in the seal chamber, and a gas for introducing the exhaust gas upstream of the butterfly valve into the seal chamber. It has a passage.

As a material for the ring-shaped seal member, spring steel or the like can be usually used because it is necessary to withstand high temperature and high pressure. Therefore, as a means for making the ring-shaped sealing member expandable and contractible, a part of it may be cut into slits (usually diagonally) to form an open ring shape.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Exhaust brake body 1 of Embodiment 1 shown in FIGS. 1 to 6
Is formed by supporting a valve shaft 6 of a butterfly valve 4 on bearings 8 and 9 in an exhaust pipe 2, and a seal member 12 provided with a seal chamber 10 at a portion where the valve shaft 6 penetrates the exhaust brake main body 1. It is fitted. The bearing 9 is a sealed bearing.

As shown in detail in FIG. 4, the seal chamber 12 has a ring-shaped opening on the valve shaft 6 side and a tapered outer wall surface, and the valve shaft 6 is inserted into the through hole 14. Then, a seal chamber side seal surface 16 on the exhaust brake body 1 side is formed on the tapered outer wall surface, and a circumferential surface of the valve shaft 6 facing the seal chamber 10 is made a cylindrical seal surface 18 on the valve shaft 6 side. Ring-shaped sealing member 20
Was fitted. Then, the gas passage 15 is communicated with the exhaust pipe 2 on the upstream side of the butterfly valve 4, that is, on the engine E side (not shown) between the through hole 14 and the valve shaft 6 so that high-pressure gas is introduced into the seal chamber 10. I decided to introduce it.

As shown in FIG. 5, the ring-shaped sealing member 20 is provided with a sealing surface 16 'which is in sliding contact with the sealing chamber side sealing surface 16 and a sealing surface 18' which is in sliding contact with the cylindrical sealing surface 18.
A part of the slope 22 is cut by a slit 22 to allow expansion and contraction.

FIG. 6 shows a state in which the actuator 24 is connected to the exhaust brake main body 1, and the valve shaft 6 exposed to the outside is shown.
The drive arm 26 attached to the actuator and the actuator 24 are connected by a link mechanism, and the butterfly valve 4 is rotated when the drive rod 28 is retracted.

Next, the operation of the first embodiment will be described. When the butterfly valve 4 rotates to close the exhaust pipe 2 (solid line in FIG. 2), the engine E side is closed and becomes a high pressure, and the pressure is introduced into the seal chamber 10 and the ring-shaped seal member 20 is closed by an arrow. (4th
). Then, the ring-shaped sealing member 20
The sealing surface 16 'of the presses the tapered sealing chamber side sealing surface 16 and seals the surface, and the component force of this pressing force in the direction of the valve shaft 6 and the member 20 is directly pressed to the valve shaft 6 side. The force causes the sealing surface 18 'to push the cylindrical sealing surface 18 to seal the penetration. The higher the pressure becomes, the higher the sealing force becomes, but when the butterfly valve 4 rotates to the valve opening side (the two-dot chain line side in FIG. 2), the force pushing the sealing surfaces 16 and 18 abruptly decreases. Therefore, the load on the actuator 24 can be reduced.

A second embodiment will be described with reference to FIGS. The sealing chamber-side sealing surface 16 of the second embodiment is provided in the radial direction of the valve shaft 6. Therefore, as the ring-shaped sealing member 20, a member having a rectangular cross section is used. Then, the opening of the seal chamber 10 is made to substantially match the width of the ring-shaped seal member 20 to facilitate the positioning of the member 20, and a gas passage 15 for introducing high-pressure gas into the seal chamber 10 is formed in the seal member 12. . The exhaust brake seal device of the second embodiment is
Similar to Example 1, high sealing performance can be exhibited.

In Example 3 shown in FIG. 9, a ring groove-shaped seal chamber 10 is provided in the valve shaft 6. The shape of the ring-shaped sealing member 20 of the third embodiment is similar to that of FIG. 8, but the sealing surface 18 'of the third embodiment is provided on the outer peripheral side of the ring. Therefore, the gas passage 15 of the third embodiment is provided in the valve shaft 6 so that the ring-shaped seal member is expanded by the high pressure gas. Further, the width of the seal chamber is made wider than that of the ring-shaped seal member 20 so that the high-pressure gas presses the ring-shaped seal member 20 toward the seal chamber-side seal surface 16 side.
High-pressure gas is introduced behind 16 '. The exhaust gas brake seal device of the third embodiment can exhibit excellent sealing properties as in the first and second embodiments.

If high-pressure gas is introduced also from the gap Δ between the valve shaft 6 and the seal member 12, the sealing chamber-side sealing surface 16 side can be sealed by the same action without widening the groove width of the sealing chamber 10. You can

[Effect of device]

As described above, the exhaust brake sealing device of the present invention uses the high-pressure gas generated by the operation of the exhaust brake to seal the portion of the valve shaft of the exhaust brake that projects to the outside.
Since the sealing member fitted around the valve shaft is pressed against the sealing surface to seal, a high sealing performance is exhibited when the exhaust brake is activated, and when the exhaust brake is released, the gas pressure is rapidly increased by the rotation of the butterfly valve. Since the pressure is reduced and the pressing force is reduced, the load on the actuator can be reduced.

[Brief description of drawings]

FIG. 1 is a front view of a seal device for an exhaust brake according to a first embodiment, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is a sectional view taken along line III-III of FIG. 3 is an enlarged view of a main part of FIG. 3, FIG. 5 is a perspective view of a ring-shaped seal member used in the first embodiment, and FIG. 6 is a perspective view showing a state in which an actuator is attached to the exhaust brake seal device of the first embodiment. FIG. 7 and FIG. 7 are cross-sectional views of an essential part of the exhaust brake seal device according to the second embodiment, and FIG.
The figure is a perspective view of a ring-shaped seal member used in Example 2,
FIG. 9 is a cross-sectional view of essential parts of the exhaust brake seal device of the third embodiment. 1 ... Exhaust brake body, 2 ... Exhaust pipe, 4 ... Butterfly valve, 6 ... Valve shaft, 10 ... Seal chamber, 12 ... Seal member, 15 ... Gas passage, 16 ... Seal chamber side sealing surface, 16 ', 18' ... Sealing surface, 18 ... Cylindrical sealing surface, 20 ... Ring-shaped sealing member.

Claims (1)

(57) [Scope of utility model registration request] 1. A cylindrical seal surface provided coaxially with the valve shaft at a penetrating portion where a valve shaft of a butterfly valve penetrates an exhaust brake main body, and a ring groove-shaped seal opening toward the cylindrical seal surface side. The chamber is formed so as to face the cylindrical seal surface, and the seal chamber-side seal surface is formed on the axial wall outer wall side of the valve shaft, and the cylindrical seal surface and the seal chamber-side seal surface are formed. A seal device for an exhaust brake, in which a expandable and contractible ring-shaped seal member that is in sliding contact with both of these is fitted in a seal chamber, and a gas passage for introducing exhaust gas upstream of a butterfly valve is provided in the seal chamber.