JPH0433509Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a shaft sealing device for an exhaust brake valve.

[Prior Art] As disclosed in Japanese Utility Model Application Publication No. 55-1905, one end of the valve shaft of an exhaust brake valve projects outward from a housing, and is coupled to a lever rotationally driven by an actuator. Therefore, in order to prevent exhaust gas from leaking from the gap between the valve stem and the shaft hole, the shaft sealing device includes a seat plate whose inner circumferential surface is in close contact with the outer circumferential surface of the valve stem, and an outer circumferential surface which is attached to the inner circumferential surface of the shaft hole. It is supported by alternately overlapping the seat plates that are in close contact with each other. That is, as shown in FIG. 3, the valve shaft 6 is inserted into the shaft hole 1 of the housing 20.
8 is supported by a bearing 8, and three seat plates 2, 3,
4 is the outer end side of the bearing 8 in the shaft hole 18 (housing 20
The bracket 7) supporting the bracket 7) is fitted in an overlapping manner. The seat plates 2, 4 have their outer peripheral surfaces brought into close contact with the inner peripheral surface of the shaft hole 18, while the intermediate seat plate 3 has its inner peripheral surface brought into close contact with the outer peripheral surface 6b of the valve shaft 6. Due to the labyrinth effect, exhaust leakage from the support portion of the valve shaft 6 relative to the housing 20 is suppressed. However, since the inner circumferential surface of the intermediate seat plate 3 comes into sliding contact with the outer circumferential surface 6b of the valve shaft 6 as the exhaust brake valve opens and closes, the wear is more noticeable compared to other seat plates, and the valve wears out after long-term use. There is a drawback that a gap is created between the shaft 6 and the intermediate seat plate 3, allowing exhaust gas to leak.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, the purpose of the present invention is to provide a system that has a simple structure and can maintain the sealing effect even if the sliding contact portion with the valve stem is worn out. An object of the present invention is to provide a shaft sealing device for an exhaust brake valve.

[Means for solving the problem] In order to achieve the above object, the structure of the present invention is such that the inner peripheral edge of an annular seat plate having a notch is fitted into an annular groove provided on the valve stem, and the inner peripheral edge of the annular seat plate is Annular seat plates that closely fit into the inner peripheral surface of the shaft hole that supports the valve shaft are superimposed on both sides.

[Operation] The inner peripheral edge of the intermediate seat plate is fitted into the annular groove provided in the valve shaft. The intermediate seat plate is pressed against the side wall of the annular groove of the valve stem by exhaust pressure acting on one side, suppressing exhaust leakage. Since the intermediate seat plate has a large contact area with the side wall of the annular groove, the sealing effect is large.

The pair of seat plates is in close contact with the inner circumferential surface of the shaft hole to prevent exhaust leakage from the outer circumference side of the pair of seat plates. The seat plates overlap each other to seal the gap between the shaft hole and the valve shaft.

Even if the intermediate seat plate wears out due to rotational friction with the valve stem, the exhaust pressure acts on one side of the intermediate seat plate and presses the other side of the intermediate seat plate against the side wall of the annular groove.
The two are maintained in close contact and exhibit a long-term sealing effect.

[Embodiment of the invention] As shown in FIG.
It crosses the exhaust passage 9 and is supported by the housing 20 at both ends by bearings 8 and 13. A bolt 1 is attached to the portion of the valve shaft 6 where the disc-shaped valve body 12 faces the exhaust passage 9.
Supported by 0. The bearing 13 supporting the end 6a of the valve shaft 6 is closed by a cover plate 16 fixed to the housing 20 with bolts 14. On the other hand, the other end of the valve stem 6 is connected from the housing 20 to the bracket 7.
It passes through and projects to the outside, and is connected to a lever (not shown). A sealing member 5 consisting of three seat plates 2, 3, and 4 is supported in a shaft hole 18 that supports a bearing 8.

As shown in FIG. 1, according to the present invention, the valve stem 6
An annular groove 26 is formed in the annular groove 26, and the inner peripheral edge of the annular seat plate 3 having a notch is fitted into the annular groove 26. On the other hand, the pair of seat plates 2 and 4 are stacked on top of each other so as to sandwich both sides of the seat plate 3, and the outer peripheral surfaces of the seat plates 2 and 4 are connected to the shaft hole 18.
be closely followed. Preferably, the outer peripheral edges of the seat plates 2 and 4 are rounded to prevent uneven contact with the inner circumferential surface of the shaft hole 18, and are configured to be in close contact with both side surfaces of the intermediate seat plate 3. The seat plates 2 and 4 are formed in advance to have an outer diameter somewhat larger than the inner diameter of the shaft hole 18, and a notch is provided so that the seat plates 2 and 4 are elastically engaged with the shaft hole 18 in a compressed state. .

In this way, the sealing member 5 consisting of the seat plates 2, 3, and 4
is held between the bearing 8 and the bracket 7, and the inner peripheral edge of the intermediate seat plate 3 is engaged with the annular groove 26 of the valve shaft 6, so that there is no space between the shaft hole 18 and the outer peripheral surface of the bearing 8. Exhaust leakage from the gap between the seat plates 2 and 4 is suppressed by the outer circumference of the seat plates 2 and 4, and exhaust leakage from the gap between the valve stem 6 and the inner circumference of the bearing 8 is suppressed by the gap between the intermediate seat plate 3 and the valve stem. 6 by engagement with the annular groove 26.

The exhaust gas passing through the gap on the inner circumferential side of the bearing 8 exerts pressure on the surface 3a of the intermediate seat plate 3, causing the seat plate 3 to move into the annular groove 2.
6, the annular groove 2
Exhaust leakage that bypasses 6 can be suppressed.

As the valve stem 6 rotates, one surface of the seat plate 3 and the annular groove 2
Even if wear occurs due to sliding contact with the side wall 26a of 6,
Since both are maintained in a close state by the exhaust pressure acting on the surface 3a, exhaust leakage can be completely prevented.

[Effects of the invention] As mentioned above, the present invention brings a pair of seat plates of the seat plates stacked on each other into close contact with the inner circumferential surface of the shaft hole,
Since the intermediate inner peripheral edge is engaged with the annular groove of the valve stem, the intermediate seat plate is in close contact with the side wall of the annular groove.
Prevents exhaust leakage from the annular groove gap. The pair of seat plates is in close contact with the inner circumferential surface of the shaft hole to prevent exhaust leakage from the outer circumference side of the pair of seat plates. The seat plates overlap each other to seal the gap between the shaft hole and the valve shaft.

Even if the intermediate seat plate thermally expands and a gap is created between the inner peripheral edge of the intermediate seat plate and the bottom of the annular groove, the overlap between the intermediate seat plate and the side wall of the annular groove allows the annular groove to be bypassed. Since the contact area between the intermediate seat plate and the side wall of the annular groove is large, the sealing effect is high.

The pair of seat plates that are in close contact with the inner peripheral surface of the shaft hole do not rotate and therefore do not wear out, but the intermediate seat plate that engages with the annular groove of the valve shaft wears due to rotational friction with the valve shaft.
Since the exhaust pressure acts on one surface of the intermediate seat plate and presses the other surface of the intermediate seat plate against the side wall of the annular groove, both are maintained in a close state and a sealing effect is exerted for a long period of time.

[Brief explanation of drawings]

Fig. 1 is a plan sectional view showing an enlarged main part of the shaft sealing device of the exhaust brake valve according to the present invention, Fig. 2 is a plan sectional view showing the entire device, and Fig. 3 is a plan sectional view showing the main part of the shaft sealing device of the exhaust brake valve according to the present invention. FIG. 2 is a plan sectional view showing the main parts of the shaft sealing device. 2, 3, 4...Seat plate, 5...Sealing member, 6...
Valve shaft, 8, 13...Bearing, 18...Shaft hole, 20...
...housing, 26... annular groove.

Claims (1)

[Scope of utility model registration request] The inner circumferential edge of an annular seat plate having a notch fits into an annular groove provided on the valve stem, and an annular seat closely fits into the inner circumferential surface of a shaft hole that supports the valve stem on both sides of the seat plate. An exhaust brake valve shaft sealing device characterized by overlapping plates.