JPH09242567A - Exhaust brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the predetermined relief pressure so as to show the function of a relief valve even in the case where one relief valve element is fixed. SOLUTION: A device is provided with a first relief valve element 29 having a through passage 33 as a passage for the exhaust gas, which is provided with an inlet in a first relief valve seat 28 side, and a second relief valve element 32, which is formed in an outlet side of the through passage 33 and which contacts and separates with/from a second relief valve seat 31b, and a relief spring 36 for energizing the first relief valve element 29 and the second relief valve element 32 in the direction for seating. The second relief valve element 32 is opened by the pressure of the exhaust gas, which enters the through passage 33, and the exhaust gas is led to a downstream side so as to prevent the excessive rise of the upstream side pressure of the exhaust gas due to the fixation of the first relief valve element 29 in the condition that an exhaust brake is operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust brake device provided with a relief valve for releasing the upstream pressure of exhaust gas in an exhaust brake valve arranged in an exhaust pipe of an engine to a downstream side.

[0002]

2. Description of the Related Art FIG. 5 is a schematic diagram showing the relationship between an exhaust brake device and an engine. The exhaust brake device 1 is
When the exhaust brake valve 4 is arranged in the exhaust pipe 3 of the engine 2, the solenoid valve 5 is turned on, and the fluid actuator 6 is operated, the valve shaft 8 of the butterfly-type brake valve body 7 is rotated to exhaust the exhaust gas. The brake valve 4 is closed to perform warm-up operation and exhaust brake action. The exhaust brake action is
It depends on the amount of the valve gap S. If the relief valve 10 is not provided, the valve gap S is set to be relatively large,
Here, since the relief valve 10 is provided, the valve clearance S is set to a small value because the braking force in the low / medium speed rotation range of the engine 2 increases.

With the exhaust brake valve 4 closed, the pressure of the exhaust pipe 3 rises when the engine 2 rotates at a high speed, and the exhaust valve 9 is damaged if this pressure rises too much. In order to prevent this, a part of the exhaust gas is discharged to the brake valve body 7 through the bypass passage 11 of the relief valve 10.
It is designed to escape from the upstream side to the downstream side.

FIG. 6 is a sectional view showing a main part of a conventional exhaust brake device. The exhaust brake device 1 is provided with a butterfly type brake valve body 7 similar to the one described above in an exhaust pipe 3 of an engine 2 shown in FIG. 5, and a relief valve 10.
The relief valve 10 has a valve chamber 15 formed in a relief valve body 14 which is provided integrally with a brake valve body 13, and a relief valve body 16 and a relief spring 17 for urging the relief valve body 16 in a direction to close the valve chamber 15 are formed in the valve chamber 15. Provided, brake valve body 13
A relief valve seat 13a is formed on the pipe wall that is integral with the exhaust pipe 3.

[0005]

However, in the conventional exhaust brake device 1 having the above-mentioned relief valve 10, the valve chamber 15 is formed in the relief valve body which is integrated with the brake valve body 13 and the exhaust pipe 3. The mutual sliding contact surface between the outer periphery of the relief valve body 16 and the inner surface of the valve chamber 15 has a large sliding resistance because the metals rub against each other, and in addition, the mutual sliding contact surface is fixed due to the adhesion of carbon or the like. However, there is a problem that the relief valve does not exhibit its function.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is that the relief valve body is hard to be fixed, and even if it is fixed, a predetermined relief pressure is secured and the function is exerted. An object of the present invention is to provide an exhaust brake device provided with a relief valve that can be used.

[0007]

In order to achieve the above object, the present invention provides an exhaust brake device provided with a relief valve for releasing a pressure on an exhaust gas upstream side in an exhaust brake valve arranged in an exhaust pipe of an engine. In, the first relief valve body having an inlet on the first relief valve seat side and having a through passage serving as a passage for exhaust gas and a second relief valve seat formed on the outlet side of the through passage are brought into contact with and separated from each other. Exhaust gas entering the through passage in a state in which an exhaust brake is activated, including a second relief valve body and an urging means for urging the first relief valve body and the second relief valve body in a seating direction. The second relief valve element is opened by the pressure of the gas to allow the exhaust gas to escape to the downstream side and prevent the upstream pressure of the exhaust gas from rising too much.

[0008]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the first embodiment of the present invention.
FIG. 2 is a side sectional view showing an essential part of an exhaust brake device including a relief valve according to the embodiment of the present invention, in which the same parts as those of the conventional device are designated by the same reference numerals, and FIG. It is the side sectional view shown.

The exhaust brake device 21 is provided with a relief valve 24 which is separate from the brake valve body 23 of the exhaust brake valve 22, and the relief valve seat 2 is provided in the relief valve body 25.
8a includes a seat member 28 and a relief spring 36 that urges the first relief valve body 29 and the second relief valve body 32 in a direction to seat the first relief valve body 29 and the second relief valve body 32. When the body 29 is stuck and does not open, the pressure of the exhaust gas entering the through passage 33 penetrating the first relief valve body 29 causes the second relief valve body 32 to open against the biasing force of the relief spring 36. Exhaust gas to the downstream side to prevent the pressure of the exhaust gas on the upstream side from rising too high.

Further, the exhaust brake device 21 can adjust the relief pressure by providing an urging force adjusting mechanism 38 for externally adjusting the set load of the relief spring 36, that is, the urging force. The relief valve 24 has a hollow rod 31 integrally formed with the first relief valve body 29, and shaft seal members 35, 35 are arranged in the relief valve body 25 to seal the outer periphery of the hollow rod 31. There is.

The exhaust brake valve 22 is provided with a relief hole 46 on the upstream side and a communication hole 47 on the downstream side of the brake valve body 7 straightly along the radial direction on the peripheral wall of the brake valve body 23, and the relief hole 46 and the communication hole. A flat receiving surface 48 is formed on the outer surface of the brake valve body 23 extending over 47. Then, the exhaust brake valve 22 has a plurality of bolts (not shown) on the receiving surface 48 via a heat insulating gasket 49 and the brake valve body 23.
A relief valve body 25 is attached to the valve shaft 8 by the operation of a fluid actuator similar to that shown in FIG.
Rotates and the brake valve body 7 is opened and closed.

The relief valve 24 is a relief valve body 25.
And a case 2 assembled with a plurality of bolts 51
6 and a cover 27 that closes the opening on the side opposite to the case 26.
And a first relief valve body 29 having a hollow rod 31 inside the relief valve body 25 and the case 26.
Is stored.

Further, the relief valve 24 has a through passage 33 serving as an exhaust gas passage in the center of the first relief valve body 29, and the exhaust gas inlet to the through passage 33 is on the first relief valve seat 28a side. And the through passage 33 that opens to the spring chamber 37 side
The second relief valve seat 31b is formed at the outlet of the second relief valve seat 31b and the annular spacer 34 fitted to the outer periphery of the small diameter end 31a of the hollow rod 31 is interposed between the second relief valve seat 31b and the second relief valve seat 31b. A relief valve element 32 is provided, and a relief spring 36 as an urging means urges the first relief valve element 29 and the second relief valve element 32 in a seating direction.

Further, the relief valve 24 includes a check valve 40 provided on the outer periphery of the case 26, and an exhaust pipe 44 for communicating the inside of the valve box 43 of the check valve 40 with a communication hole 47 on the downstream side of the exhaust gas. , A metal radiating pipe 45 connecting the relief valve body 25 and the case 26, and a cover 27 is integrally provided with an inward pressing cylinder portion 27c. The cylinder member 27c prevents the seat member 28 from coming off. I am doing it.

The relief valve body 25 has a female screw 5 on the side closer to the cover 27 with the intermediate inward flange 52 as a boundary.
Large-diameter hole 53 having 0 and subsequent intermediate-diameter fitting hole 54
And a small diameter hole 55 are provided, and the bearing hole 5 is provided on the side closer to the case 26.
6 and the small diameter hole 55 forms the valve chamber 57. Further, the relief valve body 25 is provided with a straight introduction hole 58 communicating with the large diameter hole 53 on an extension of the relief hole 46 of the brake valve body 23, and a lead-out hole 59 is formed at a position corresponding to the communication hole 47.

The case 26 has an outward flange 6 at one end.
1, an adjusting cylinder 62 is integrally provided at the other end, and an internal thread 62a is provided on the inner circumference of the adjusting cylinder 62. The outward flange 61 is provided on the end surface of the brake valve body 23 via a heat insulating gasket 63.
Are assembled to the relief valve body 25 with a plurality of bolts 51 to form a spring chamber 37, and the second relief valve body 32 and the spacer 34 are housed in the spring chamber 37.

The cover 27 has a flange-shaped head 27a.
And a male screw portion 27b and a tubular portion 27c are integrally provided, the tubular portion 27c has a plurality of through holes 27d, and the male screw portion 27b is screwed into the female screw 50 to be attached to the relief valve body 23. The tip of 27c presses the sheet member 28 to prevent it from coming off.

The seat member 28 is provided with a first relief valve seat 28a having a tapered hole in the center and a straight hole 28b following the first relief valve seat 28a, and is press-fitted into a fitting hole 54 to be fitted into the relief valve body 25. is there.

The first relief valve body 29 includes a valve body 30.
And a hollow rod 31 for receiving the guide, and a second relief valve seat 31b is formed at the tip of the small-diameter end portion 31a of the hollow rod 31.
And is supported by the bearing bush 70 and can be brought into and out of contact with the first relief valve seat 28a.
The small-diameter end portion 31a penetrates the spacer 34, projects into the spring chamber 37, and is urged by a relief spring 36 in a seating direction.

The second relief valve body 32 is a valve body 32a.
And a flange 32b are integrally formed, a blind hole 32c is opened in the center of the flange 32b side, and a small diameter end 31a is fitted into the blind hole 32c. Relief spring 36
When the first relief valve element 29 normally operates by being fitted into one end side of the relief spring 36, it serves as a guide for the relief spring 36.

[0021] Here, the pressure receiving area of the first relief valve body 29 A _1, the pressure receiving area of the second relief valve 32 and A ₁ ≧ A ₂ represented by A _2, the first relief valve body 29 Let P _{1 be} the relief pressure of the second relief valve element 32 and P _{2 be} the relief pressure of the second relief valve element 32, the force that the first relief valve element 29 compresses the relief spring 36 is F ₁ and the second relief valve element 32 relieves. each force to reduce the spring 36 F ₂ is, F ₁ = a
₁ × P ₁ and F ₂ = S ₂ × P ₂ , and the relief pressure of the second relief valve element 32 is calculated by P ₂ = (A ₁ / A ₂ ) × P ₁ .

Relief pressure P _{1 of} the first relief valve body 29
On the other hand, the relief pressure P ₂ of the second relief valve body 32 is slightly higher than this.

The shaft seal member 35 is made of stainless steel (JI
An outer ring 68 made of S symbol SUS403) and an expanded graphite inner ring 69 fitted to the inner periphery of the outer ring 68 are used to form the bearing hole 5
The bearing bushes 70 are inserted at two positions inside the member 6 and are prevented from coming off by a pressing member 71. When the pressing member 71 is removed, it can be taken out. The shaft seal member 35 is the hollow rod 3
In order to fit the outer periphery of the first relief valve body 1 as a press-molded product, the inner diameter dimension is finished with high precision.
The outer periphery of the rod 31 of No. 9 is sealed and the relief valve chamber 57
The exhaust gas therein is prevented from flowing into the spring chamber 37.

The relief spring 36 is arranged between the flange 32b of the second relief valve body 32 and the spring receiving portion 74 of the spring adjusting member 65, and urges the second relief valve body 32 at the same time. The first relief valve element 29 is biased in the closing direction via a spacer 34 that is movable in the spring chamber 37.

The biasing force adjusting mechanism 38 includes a spring adjusting member 65.
Is movably inserted in the spring chamber 37, and the adjusting bolt 76 is screwed to the adjusting cylinder 62. Spring adjusting member 65
Includes the spring receiving portion 74 and the relief valve body 3 having a second end surface.
2 and a bar-shaped stopper 75 facing each other. Adjustment bolt 76 screwed into the female screw 62a on the inner surface of the adjustment cylinder 62.
Has an inner end abutting the spring adjusting member 65 and a nut 77 screwed to the outer end, and is positioned by the nut 77.

Then, the urging force adjusting mechanism 38 adjusts the position of the stopper 75 by turning the adjusting bolt 76 to regulate the vibration of the first relief valve body 29 at the time of engine resonance and, at the same time, the relief spring 36. It is also possible to adjust the relief pressure based on.

As the check valve 40, a spherical check valve body 42 biased by a spring having a small spring constant is used, and when the second relief valve body 32 is opened, exhaust gas is passed to the downstream side by an exhaust pipe 44. It also plays a role of preventing backflow when the first relief valve element 29 is normally operated. The heat radiating pipe 45 has a male screw 45a at one blind side and is screwed into the relief valve body 25 so as to be blindly connected to it. To prevent the temperature from rising.

In the relief valve 24, when the exhaust brake is in operation, the first relief valve body 29 is in the seat member 2
When the upstream side pressure of the exhaust gas tries to rise excessively without being opened because it is fixed to the valve 8, the second relief valve body 32 is opened by the pressure of the exhaust gas entering the through passage 33, and the check valve is opened. The exhaust gas is released to the downstream side through the exhaust pipe 40 and the exhaust pipe 44, and the pressure of the exhaust gas on the upstream side is lowered.

The operation of the exhaust brake device according to the first embodiment of the present invention will be described. The exhaust brake valve 22 is open when the fluid actuator 20 is not in operation, and when an exhaust brake is required from this state, when the fluid actuator is operated, the exhaust brake valve 22 is closed. If the vehicle continues to run downhill in this state, the exhaust pressure of the exhaust gas G upstream of the exhaust brake valve 22 increases in the exhaust pipe when the engine speed increases. This exhaust pressure acts as back pressure on the exhaust brake valve 22.

However, since the relief valve 24 is provided, when the exhaust pressure reaches or exceeds the set pressure, the relief spring 3 is released.
The first relief valve element 29 is separated from the first relief valve seat 28a against the urging force of 6, and a part of the exhaust pressure is released through the relief hole 46, the introduction hole 58, the valve chamber 57, the discharge hole 59 and the communication. Hole 4
7 to the downstream side of the exhaust brake valve 22. When the first relief valve body 29 is fixed to the seat member 28, the second relief valve body 32 is opened, and a part of the exhaust pressure is passed through the through passage 33, the spring chamber 37, and the check valve. Valve 4
0 and the exhaust pipe 44 to escape to the downstream side of the exhaust brake valve 22.

As a result, when traveling downhill on a slope, even if the engine speed increases and the exhaust pressure on the upstream side rises, the exhaust brake valve 2 remains closed.
Since the upstream side and the downstream side of 2 communicate with each other, the exhaust pressure on the upstream side is kept constant, and an abnormal increase in the exhaust pressure leading to the engine stop is reliably suppressed.

According to the first embodiment of the present invention,
Since the urging force adjusting mechanism 38 is provided, the adjusting bolt 76
Change the position of the spring adjustment member 65 by turning
There is an advantage that the set load of the relief spring 36 can be adjusted from the outside to eliminate the variation of the relief pressure due to the variation of the set load.

FIG. 3 is a graph showing an example of the relationship between the engine speed n and the exhaust gas pressure P in the case of the relief valve according to the above embodiment of the present invention. When the exhaust brake valve is actuated and the first relief valve element 29 operates normally, the exhaust gas pressure P is 0 point, the A point at which the engine exhaust valve opens, and the first relief valve 29 opens at P _1. Kg
/ Via point B cm ² settles to point E P ₂ Kg / cm ^2. If there is no second relief valve body 32 and the first relief valve body 29 is fixed to the seat member 28, the exhaust gas pressure P is 0 point, A point, B point and P ₂ Kg.
It further rises from the C point of / cm ² and reaches the D point. However, in the present invention, since the second relief valve body 32 is provided,
This opens at point C and the exhaust gas pressure P remains at point E of P ₂ Kg / cm ² .

FIG. 4 is a vertical cross-sectional view showing a relief valve according to a second embodiment of the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals and the duplicate description thereof will be omitted. The relief valve 24 is provided with a first relief spring 36a for urging the first relief valve body 29, and a second relief spring 36b for urging the second relief valve body 32 separately from the first relief spring 36a. The spacer 34 has an outer diameter larger than that of the second relief valve body 32, is arranged between the spacer 34 and the inner surface of the end plate of the case 26, and the adjusting bolt 76 is provided integrally with the spring adjusting member 65. is there.

[0035] Here, A ₁ and the pressure receiving area of the first relief valve body 29, the pressure receiving area of the second relief valve 32 and A _1> A ₂ represented by A _2, the first relief valve body 29 Is P ₁ , the relief pressure of the second relief valve body 32 is P ₂ , the set load of the first relief spring 36 a is Fa,
When the set load of the second relief spring 36b is Fb, the first relief valve element 29 causes the first relief spring 36 to move.
a and the force F ₁ for contracting the second relief spring 36b and the force F ₂ for contracting the second relief spring 36b by the second relief valve body 32 are respectively F ₁ = A ₁ × P ₁ = Fa + F
b, F ₂ = S ₂ × P ₂ = Fb, and the relief pressure of the second relief valve body 32 is P ₂ = (A ₁ × P ₁ / S ₂ ) +
Calculated by (Fb / S ₂ ). This relief valve 24
It includes a pressure receiving area A ₁ of the first relief valve body 29, even when the difference between the pressure receiving area A ₂ of the second relief valve 32 is large, to adjust the set load Fb of the second relief spring 36b There is an advantage that it can be dealt with by doing so.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention.

[0037]

According to the present invention, a first relief valve body having an exhaust gas passage having an inlet on the first relief valve seat side and a second relief valve seat formed on the outlet side of the passage are provided. Exhaust gas that enters into the through passage with the second relief valve element that is in contact with and separated from the second relief valve element and the urging means that urges the first relief valve element and the second relief valve element in the direction of seating the second relief valve element By opening the second relief valve body by the pressure of the gas to allow the exhaust gas to escape to the downstream side and prevent the upstream side pressure of the exhaust gas from rising too much, the first relief valve body is fixed. Also has an effect that a predetermined relief pressure can be secured and the function of the relief valve can be maintained. Further, by providing the first urging means for urging the first relief valve body and the second urging means for urging the second relief valve body, the pressure receiving area of the first relief valve body is provided. With this, it is possible to cope with the case where the difference between the pressure receiving area of the second relief valve body is large.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a main part of an exhaust brake device including a relief valve according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing a relief valve according to the first embodiment of the present invention.

FIG. 3 is a graph showing an example of the relationship between the engine speed and the exhaust gas pressure in the case of the relief valve according to the first embodiment of the present invention.

FIG. 4 is a side sectional view showing a relief valve according to a second embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a relationship between an exhaust brake device and an engine.

FIG. 6 is a side sectional view showing a main part of a conventional exhaust brake device.

[Explanation of symbols]

 21 exhaust brake device 22 exhaust brake valve 23 brake valve body 24 relief valve 25 relief valve body 26 case 28 seat member 28a first relief valve seat 29 first relief valve body 31 hollow rod 31b second relief valve seat 32 second 2 Relief valve body 33 Through passage 34 Spacer 36 Relief spring (biasing means) 37 Spring chamber 38 Biasing force adjusting mechanism 40 Check valve 44 Exhaust pipe 45 Radiating pipe 54 Fitting hole 57 Valve chamber 65 Spring adjusting member

Claims (3)

[Claims] 1. An exhaust brake device provided with a relief valve for releasing a pressure on an exhaust gas upstream side of an exhaust brake valve arranged in an exhaust pipe of an engine, wherein an inlet is provided on a first relief valve seat side, A first relief valve body having a through passage that serves as a passage, a second relief valve body that comes into contact with and separates from a second relief valve seat formed on the outlet side of the through passage, the first relief valve body, and Urging means for urging the second relief valve body in a seating direction, the second relief valve body being opened by the pressure of the exhaust gas entering the through passage in the operating state of the exhaust brake. An exhaust brake device characterized in that the gas is allowed to escape to the downstream side and the upstream side pressure of the exhaust gas can be prevented from rising excessively. 2. The exhaust brake device according to claim 1, wherein a first urging means for urging the first relief valve body and a second urging means for urging the second relief valve body. And an exhaust brake device. 3. The exhaust brake device according to claim 1 or 2, wherein the first relief valve body is provided with a hollow rod on a side facing the first relief valve seat, and the hollow rod is provided. An exhaust brake device, characterized in that a second relief valve seat is provided at the tip of the.