Pressure limiting seal piston and exhaust brake butterfly valve thereof

Abstract

The invention relates to a pressure limiting seal piston which comprises a step-shaped piston body, wherein the step-shaped piston body comprises a tappet rod (21) and a support seat (22); a first annular groove (211) is arranged on the outer surface of the tappet rod (21); the pressure limiting seal piston (20) is slidably installed in a pressure limiting device shell (8) on the side wall of a valve body (1) of an exhaust brake butterfly valve; the tappet rod (21) convexly extends to an inner cavity of the valve body (1) by a through hole (100) arranged in the inner wall of the valve body (1) and is correspondingly inserted into a pressure relief notch (31); the support seat (22) is arranged on the pressure limiting device shell (8); static pressure holes (9) are also arranged outside the through hole (100) and in the air inlet cavity wall; the first annular groove (211) is positioned inside the through hole in the inner wall of the valve body; the bottom of the support seat (22) is provided with a pressure limiting spring (7); and the pressure limiting spring (7) is butted against a spring end cover (40). The invention has the advantages of simple and compact structure, less pressure limiting seal piston motion resistance, less waste gas leakage and capability of effectively controlling the position and the motion stroke of the piston.

Description

technical field [0001] The invention relates to a pressure-limiting sealing piston and an exhaust brake disc valve thereof, belonging to the technical field of machinery manufacturing. Background technique [0002] The exhaust brake is an auxiliary braking device for the vehicle, especially suitable for (heavy) trucks and (large) passenger cars and engineering vehicles, which can enhance the braking performance of the vehicle without using or less use of the main brake (traditional friction). Brake), the vehicle can be controlled within a certain safe speed range, preventing vehicle braking failure and ensuring driving safety. [0003] The existing exhaust brake is mainly composed of a cylinder or a vacuum booster cylinder and an exhaust brake valve connected to it. In the normal driving state of the vehicle, the exhaust gas of the engine flows through the exhaust brake valve and is discharged. When braking is required, the vehicle's control system controls the movement of...

AI Technical Summary

Problems solved by technology

Since the existing tappet adopts an equal-diameter structure, it is not easy to control its position and movement stroke

At the same time, under the action of air flow, the tappet is easy to be attached to the side wall of the tappet hole due to the Coanda effect, resulting in a large amount of gas leakage and affecting the braking effect.

In addition, since the top of the tappet protrudes inside the valve body, the spring installed in the inner cavity of the tappet works in the high-temperature environment of the engine exhaust in the valve inner cavity, and it is very easy to fail due to thermal deformation.

Have again, in order to ensure that the existing exhaust brake valve reaches a good braking effect, the rigidity of the spring that is required to be arranged in the inner cavity of the tappet is relatively large, and its rigidity is similar to the valve spring rigidity of the engine. , the two are prone to resonance, increased noise, and even bring safety hazards

Moreover, there are usually multiple cylinders in the engine, and different cylinders perform work in the order of suction, pressure, explosion, and discharge. The engine exhaust gas in the intake chamber of the valve body enters in a pulsating manner, and the air pressure is unstable.

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