A kind of silencer
Technical field
The present invention relates to a kind of motor exhaust noise reducer, relate in particular to a kind of silencer.
Background technique
Hydraulic shovel, as a main machine of engineering machinery, is being brought into play very important effect in national economy.Along with improving constantly that ambient noise requires, the radiated noise of excavator has also been listed state decree regulatory control scope in, and excavator radiated noise limit value requires also reduced year by year.Meanwhile, can meet concerned countries decree laws and regulations requirement, determine that can excavator sell on this market.Noise problem is to determine one of important prerequisite that excavator product is sold in the world, is also one of anxious key technology that must solve of energy-saving and emission-reduction, is signifying the core technology such as travelling comfort, the stability level of excavator product.
The exhaust noise of excavator is one of main contribution of machine external radiation noise, and the main component of exhaust noise is exhaust fundamental frequency noise and harmonic noise, especially second harmonic noise.If at silencing apparatus internal placement resonant cavity, to reduce low frequency noise, the volume of silencing apparatus must become very large so, due to the restriction in space, increases the more difficult realization of volume.And if at silencing apparatus internal placement 1/4 wavelength pipe, wavelength pipe must become very long, more difficult equally realization, the length computation formula of its wavelength pipe is as follows:
In formula: c---the velocity of sound under exhaust true temperature;
F---intend the frequency noise of noise elimination;
Therefore, silencing apparatus itself is very low to the sound deadening capacity of exhaust fundamental frequency noise and second harmonic noise, the more difficult requirement that reaches complete machine noise elimination.
Summary of the invention
The object of the invention is to provides one further to fall low noise silencer for the limited problem of existing silencing apparatus low frequency noise elimination noise reduction effect.
Technological scheme of the present invention is achieved in that a kind of silencer of structure, comprise guard shield and be positioned at the silencing apparatus of guard shield below, vertically arrange from guard shield below and upwards penetrate the tail pipe of guard shield to guard shield top, tail pipe lower end is connected with silencing apparatus, below guard shield, have the blind pipe of one end sealing at least, the opening end of blind pipe is connected on the wall of tail pipe bottom and tail pipe internal communication.In the present invention, exhaust noise is during via tail pipe, and the fundamental frequency of exhaust noise and harmonic noise composition enter blind pipe, and application interference of sound principle, offsets, and the tail gas after noise elimination passes through outside outlet pipe discharge machine again, reaches the object that makes minimumization of exhaust noise.
In silencer of the present invention, blind pipe horizontal positioned, blind pipe horizontal positioned is convenient to the layout of blind pipe.Two or three of optimum blind pipe numerical digits, layout is parallel to each other between blind pipe.
In silencer of the present invention, tail pipe sectional area is greater than the sectional area of the outlet pipe of silencing apparatus, and the outlet pipe of silencing apparatus is inserted in tail pipe from tail pipe bottom.Tail pipe bottom is horn-like.
In silencer of the present invention, in guard shield lower partition, offer and be convenient to complete machine ventilation and heat vent hole, tail pipe is fixed on dividing plate, tail pipe lower end is fixedly connected on dividing plate, the outlet pipe of silencing apparatus not directly contiguously sleeve in described tail pipe bottom, when the tail gas of discharging at the outlet pipe of silencing apparatus is discharged at a high speed through tail pipe, outlet pipe at silencing apparatus will produce negative pressure in the gap of tail pipe sleeve part, thereby the hot air of guard shield below is drawn in tail pipe and is discharged with motor exhaust, be conducive to reduce the temperature of guard shield below engine compartment.
In silencer of the present invention, tail pipe internal placement has webmaster, between webmaster and tail pipe, is filled with sound-absorbing material.
The present invention compared with prior art, advantage of the present invention: in the present invention, exhaust noise is during via tail pipe, the fundamental frequency of exhaust noise and harmonic noise composition enter blind pipe, application interference of sound principle, offset, the tail gas after noise elimination passes through outside outlet pipe discharge machine again, reaches the object that makes minimumization of exhaust noise.
Brief description of the drawings
Fig. 1 is the structural representation of silencer of the present invention;
Fig. 2 is silencer plan view of the present invention.
Component title and sequence number in figure:
Guard shield 1, the first blind pipe 2, the second blind pipe 3, silencing apparatus 4, dividing plate 5, tail pipe 6, webmaster 7, sound-absorbing material 8.
Embodiment
Below in conjunction with brief description of the drawings specific embodiments.
As shown in Figures 1 and 2, silencer in the present embodiment, comprises guard shield 1 and is positioned at the silencing apparatus 4 of guard shield 1 below, vertically arranges and upwards penetrates the tail pipe 6 of guard shield 1 to guard shield 1 top from guard shield 1 below, and tail pipe 6 lower ends are connected with silencing apparatus 4.Chamfered has been carried out in tail pipe 6 bottoms, makes it be horn-like.The sectional area of tail pipe 6 is greater than the sectional area of the outlet pipe of silencing apparatus 4, the outlet pipe of silencing apparatus 4 is not directly inserted in tail pipe 6 contiguously from tail pipe 6 bottoms, between muffler tail pipe and tail pipe, there is the space that tail pipe inner space is communicated with guard shield lower space, outlet pipe at silencing apparatus will produce negative pressure in the gap of tail pipe sleeve part, thereby the hot air of guard shield below is drawn in tail pipe and is discharged with motor exhaust, be conducive to reduce the temperature of guard shield below engine compartment.。Guard shield 1 bottom is provided with dividing plate 5, and the bottom of tail pipe 6 is fixedly mounted on dividing plate.Below guard shield 1, above dividing plate, have the first blind pipe 2 and the second blind pipe 3, the first blind pipes 2 and the second blind pipe 3 horizontal positioned, horizontal positioned is convenient to the layout of blind pipe; One end sealing of the first blind pipe 2 and the second blind pipe 3, the opening end of the first blind pipe 2 and the second blind pipe 3 is connected on the wall of tail pipe 6 bottoms and tail pipe 6 internal communication.Tail pipe 6 internal placement have webmaster 7, between webmaster 7 and tail pipe 6, are filled with sound-absorbing material 8.In the present invention, exhaust noise is during via tail pipe, and the fundamental frequency of exhaust noise and harmonic noise composition enter blind pipe, and application interference of sound principle, offsets, and the tail gas after noise elimination passes through outside outlet pipe discharge machine again, reaches the object that makes minimumization of exhaust noise.
In the present invention, the length computation formula of the first blind pipe 2 and the second blind pipe 3 is as follows:
In formula: c---the velocity of sound under exhaust true temperature;
F---intend the frequency noise of noise elimination; In the present embodiment, select two main frequency noises, two different blind pipes of length of Technology design.In actual applications, the radical of blind pipe can arrange according to concrete motor and silencing apparatus, selects three or more blind pipe.