FIELD OF INVENTION
The invention relates to an improved hydraulic system for tractor to increase hydraulic pump life and reduce hydraulic born noises.
BACKGROUND OF THE INVENTION
There are a number of reasons of fluid born noise, mainly the hydraulic system oil & its viscosity, Volume & quantity of oil flowing through hydraulic system, pressure surges in between pump flow, impact of hydraulic oil on the inner face of hydraulic conduits, pressure relief valve opening in system & flow through filter assembly of tractors. These reasons more frequently depends upon each others behavior. As noise generation in hydraulic system is one of the critical issues causing discomfort to customer & reduction of the performance of hydraulic system, it is necessary to reduce the level of noise.
The causes of the hydraulic noise are inter dependable. In winter season temperature goes down reducing the oil temperature below 15°C. This causes an increase in oil viscosity and pump applies suction pressure on the oil, forcing oil to flow inside the hydraulic routing. With increased viscosity, oil faces more frictional losses inside the conduit. The energy in the oil is converted into heat 85 sound energy, requiring more effort of pump to suck (create more suction pressure) this oil into it. When this viscous oil passes through filter assembly due to higher viscosity, it does not easily get filtered. Tendency of oil becomes such that it tries to choke/clog filter paper. As filter paper area is less, it gets chocked easily. So, pump is required to generate more suction pressure on the oil in
filter assembly, which results in more load on pump. Due to more load, mechanical noise level gets increased. After Chocking of filter assembly, substantial pressure drop is created across filters inlet & outlet port causing filter relief valve to open. A flow is then bypassed through a relief valve, opening towards the inlet port of pump. Due to small opening in filter assembly relief valve as compared to filtration area, a substantial amount of noise gets developed in filter assembly. Due to more viscous oil & suction pressure from pump side, filter paper tends to twist called pleat bunching causing filter to fail, thereby adding more contamination risk to pump. A more viscous & contaminated oil flows from filter assembly to suction port causing a noise similar to marbles flowing through pipes & this is much more noisy as compared with less viscous & less contaminated oil. Further more, this more viscous & contaminated oil when compressed in gears of hydraulic pump explodes creating noise similar to blasts & it damages the internal cavity of the pump body. This results in frequent premature service changes of hydraulic filter & decrease in efficiency of hydraulic pump causing more load on tractor engine & less fuel efficiency.
Hydraulic system of an Agricultural tractor is basically an Open Center Hydraulic system which comprises of a positive displacement gear pump, Filter assembly, Control valve assembly, Cylinder, Piston, Ram arm & Control linkages. Presently, Agricultural tractors are equipped with Automatic depth & draft control system for controlling the Depth & Draft of implements for precise planting/ drilling and primary field operations.
Being an open center system with positive displacement, gear pump is directly mounted on engine and hydraulic system runs as long as engine runs which is called "Live Hydraulic System". In this system, hydraulic gear pump continuously develops suction pressure on hydraulic oil
present in rear axle housing through filtration assembly. A filtration assembly consists of suction conduit from rear axle to filter, spin-on type filter & secondary conduit from filter to pump. During the field operation, once controlled depth & draft are achieved, Hydraulic system comes to the neutral condition & Returned oil through control valve assembly goes back to the sump. In most of the Hydraulic system of Tractor, Transmission oil is used for Hydraulic system.
From contamination point of view in case of tractor hydraulic system, filter assembly is used from rating 15-25 micron depending on their tractor hydraulic requirement. Most of tractor manufacturers use spin in type replaceable filters in hydraulic system. However, hydraulic system of tractor is associated with several disadvantages with respect to noise generation. One of the disadvantages is noise generation in system, which is of two types, fluid born noise & mechanical noise. Fluid born noise is one which is caused due to flowing & churning of hydraulic oil in between the system, pressure or flow pulsation etc & mechanical noise is one which generates through mechanical engagement of gear tooth of hydraulic gear pump, vibrations in routings etc. Hence, a noise generated in hydraulic system is added to overall noise level of tractor & also more noise in system corresponds to lower performance of the hydraulic system.
Hence, to reduce the overall tractor noise level & build a better hydraulic system, it is necessary to reduce hydraulic noise.
OBJECTS OF THE INVENTION
The principal object of the invention is to propose an improved hydraulic system for tractor to increase hydraulic pump life and reduce hydraulic born noises.
Another object of the invention is to propose an improved hydraulic system for tractor to increase the performance of hydraulic system.
Still another object of the invention is to propose an improved hydraulic system for tractor to reduce the noise level & increase pump life without causing more service cost.
Yet another object of the invention is to propose an improved hydraulic system for tractor to reduce hydraulic filter pleat bunching.
STATEMENT OF INVENTION
According to this invention, there is provided an improved hydraulic system for tractor to increase hydraulic pump life and reduce hydraulic born noises comprising of an improved filter having increased filtration area to accommodate large volume of flow wherein filter unit is having a provision to reduce hydraulic filter pleat bunching.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein:
Fig. 1 shows ideal filter condition before filtration. Fig. 2 shows: pleat blunching of filter after filtration. Fig. 3 shows: conventional filter. Fig. 4 shows: filter of the present invention.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS;
According to this invention, there is provided an improved hydraulic system for tractor to increase hydraulic pump life and reduce hydraulic born noises comprising of an improved higher capacity filter having increased filtration area to accommodate large volume of flow wherein filter unit is having a provision to reduce hydraulic blunching.
Pleat Bunching Condition
Most new elements have properly defined pleat shapes. Pleats should be longitudinal and evenly spaced. In case, the pleats are wavy or bunched up, it indicates that the element was subjected to high differential pressure or the flow was fluctuating frequently. In most hydraulic systems, fluctuation in flow is a normal phenomenon. A properly sized filter should not be affected by flow fluctuation. Either condition (high differential pressure drop or flow fluctuation these are generally caused by varying of fluid) could allow the housing bypass valve to open frequently and cause the oil to bypass the element, resulting in high particle counts. Reference may be made to fig. 1 and 2.
To overcome the problem of pleat bunching, physical property of filtration paper has been changed i.e. Stiffness of the filtration paper is increased.
The filtration area of the filter is increased such that it can accommodate large volume of flow. Length of filter has been increased to 142 mm-166.9 mm. (Drawings attached), which causes increase in surface area from 37454mm2 to 44022mm2. So, percentage increase in filtration area is 17%. Reference may be made to fig. 3 and 4. This provision optimizes the oil flow passing per square centimeter of filter paper, Which also results in more filter flow capacity as compared with existing filter with same filtration rating. As this modification results in higher flow capacity of filter, an overloading of pump is minimized which it is required to do with less flow capacity filter. Therefore, pressure drop across filter gets controlled & hence the opening of filter relief valve.
This ensures the proper & complete filtration of hydraulic oil in tractor hydraulic system, which adds life to the hydraulic pump & ultimately to tractor hydraulic system. Also a risk premature failure of filter assembly gets controlled giving more service life for particular filter & reduces the service cost of tractor. As contamination gets properly filtered, a corrosion of hydraulic pump body due to contamination is controlled with increased efficiency of hydraulic pump and less load on tractor engine. This results in increase of fuel efficiency of tractor.
Advantages:
• A control of pressure drop across filter, which results in less load on pump reducing the noise level 8s increasing the fuel efficiency of tractor.
• Minimized frequent 8s continuous opening of filter relief valve, which results in reduction of the noise level of hydraulic system & ensures proper cleanliness of fluid fed to the hydraulic system.
• Reduction of the premature filter failures 8s extension of the filter change period
• Less service cost to the farmer for hydraulic system.
(Table Removed)
lt is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-

WE CLAIM:
1. An improved hydraulic system for tractor to increase hydraulic pump life and reduce hydraulic born noises comprising of an improved filter having increased filtration area to accommodate large volume of flow wherein filter unit is having a provision to reduce hydraulic blunching.
2. An improved hydraulic system for tractor as claimed in claim 1, wherein the length of filter is increased from 142 to -166.9 mm and the surface area is increased 37,454 to 44022 mm2.
3. An improved hydraulic system for tractor as claimed in claim 1 or 2, wherein the filtration paper has increased stiffness.
4. An improved hydraulic system for tractor substantially as herein described with reference to the accompanying drawings.