v—Linear velocity in the two endpoint of the blade line of the moving blade

—Moving blade line two endpoints, design value for linear 25m/s; The chopping cylinder speed, the design value is 2100r/min.

Substitue the above data into the above type we obtained that the chopping cylinder diamete is 227mm, in this design we select chopping cylinder diameter for 680 mm.

3.3. Helicinae and Throwing Apparatus

As Figure 6 shows, helicinae and throwing apparatus is mainly comprised of auger conveyor, throwing impeller and throwing canister, etc. And the auger conveyor is mainly made up of plummer block, augering trough, augering axle, augering blade and augering axle pulleys, etc..

Basic Dimensions for Auger Conveyor

Auger conveyor pass through the bottom of the driving cab,according to operating requirements ,make augering trough L= 720mm augering axis diameter d = 60mm , augering blade diameter r = 270mm, Screw torque S = 250mm

Figure 6. Sketch of helicinae and throwing apparatus

1. Plummer block 2. Augering trough 3.Augering axle

 4. Augering blade 5. Impeller seaming 6.Impeller shaft

4. Feld Experiment and Analysis of the Results

4.1 Test Condition

We chose click on ChangYi farm, WeiFang city, ShanDong province as the Test site .The Plots are a no-till seeding Corn land in one year two ripe area. The row spacing are 275mm, line spacing are 650 mm, the corn plant height are2520mm and the stem diameter is 25 mm, the lowest height for ear are 920mm, bending rate is 2.6%, plant lodging rate is less than 2%, cluster prolapse rate is 2%, maize yield rate is 5912kg / hm2, moisture content of the stalks is 75%.

4.2 Test Method

According to the quality inspection index of the harvest quality of corn combine established by the master station of farm machinery test of Ministry of Agriculture, performance test content of harvest quality includes the forward speed of the machine, kernel lossing rate, cluster lossing rate, kernel crushing ratio, working productivity, etc. the main inspection factors are the test program of corn harvest machine and the test items and test method of corn harvest machine [14-15].

4.3 Test Results and Analysis

During the test process ,the prototype operates smoothly, safely and reliably, the working parts can effectively completed picking, rising and transportation, setting into the box, stalks cutting, conveying, chopping, throwing and collection and root crop crushing of corn grain. The stubble height of corn straw are tidy; Gripping conveying works smoothly, and reliably; The length of the stalks are tidy even after they are chopped, and can satisfy the tidy and the requirements of Silage process. The main operation performance index of the Prototype are shown. which can meet the design requirements.

5 Conclusions

(1) On the basis of a large number of testing ,we optimized 4YQZ - 3A Combine Harvester for Corn, and solved the adaptability of different line spacing range from 500mm to 800mm , finally have improved the reliability of the stem gripping delivery mechanism.(2) Developed the applicable corn harvest machine chassis and serializationed and modularized vertical spike picking shredding mechanism, Chopped stalks are casted by helicinae and throwing apparatus, the structure is simple and it operate smoothly, safely and reliablely.(3)This machine can once completed picking, rising and transportation, setting into the box, stalks cutting, conveying, chopping, throwing and collection and root crop crushing of corn grain. Field test shows that the economic technology indexes of this machine reaches relevant national standards, and also provides applicable new aircraft thefor the recycling of stalks, the development of animal husbandry and increase of peasants income .

Design and Experiment of 4YQZ-3A Combine

Harvester for Corn

Abstract—Due to the problem of the low retrieving rate of straw while harvesting, fodder went sort in stock raising and to overcome the practical problem of corn harvester reaping both corn stalk and spike while in operation, 4YQZ-3A combine harvester was designed, analyzed and the parameters of key components were pointed out for better gripping delivery mechanism, vertical picking and chopping cutter, helicinae and throwing apparatus.During the corn harvesting season, numerous performance testing and the production assessment were carried out in the field. Results achieved from the experiment indicate that the whole machine has better performance and can accomplish reaping both corn stalk and spike well.

Keywords- corn harvester; picking and threshing harvester; design; Experiment

1.introduction

Corn is China's second-largest food crop, occupies an important position in food production[1]. Maize straw contains a lot of crude protein, crude fat and fiber nutrient component, etc. Thus it is one of the most perfect forage of high quality in animal husbandry.The national annual production of corn straw is about 60,000 tons, which is a huge potential forage source [4].Corn harvester reaping both corn stalk and spike can complete the harvest of corn ear and stalks within one time, so it has significant economic, social and eco- system efficiency [5-6]. At present, corn harvester reaping both corn stalk and spike still develops very slow, and the domestic model mainly are hanging type. Because of underpowered, low production efficiency and straw cleanness, it has not been rapidly promoted [7-8].Foreign models are mainly Ukrainian KCKY-6 Corn harvest machine and Corn Star series united harvest machine developed by Kempe Co. in German, due to untidy stubble height and higher price, this type of air-craft is not suitable for China's national conditions [9-11].

Foundation item: Public beneficial(agriculture)Science research fund issue(200903059-04)

On the basis of the "tenth-five" national research tackle key problems in science and technology research, in this article 4YQZ-3A combine harvester was designed, which combines existing corn harvest and corn silage mechanization technique and improves the design and optimizes the combination for each working device. During the of harvest corn ear, the 4YQZ-3A combine harvester can also complete cutting, conveying, chopping collection and root crop broken tasks and so on; With the popularization and appli-cation of this technique , we can solve the problem of corn straw recovery and reduce the waste of straw resources and improve the environment and soil pollution caused by straw burning. There into, the straw recovery can provide high quality feed for livestock and reduce the excessive dependence on pasture, so this technique has important practical significance to our country's increasingly developing animal husbandry and related industries.

2. Overall Institutions and Main Technical Indicators

2.1. Whole Structure and Work Principle

As shown in figure 1, 4YQZ-3A combine harvester for corn is mainly made up of gripping delivery mechanism, spike picking device, stem shredding mechanism, cast cylinder, spike collecting box, stem crushing box, counters-field device and helicinae and delivery apparatus of stalks, etc. This machine can once completed the picking, rising and transportation, setting into the box, stalks cutting, conveying, chopping, throwing and collection and root crop crushing of corn grain. While the machinesk is operating, nearside divider subdivided maize plants, reciprocating cutter cut the plants, clamping chain clamps maize plants of which root is sundered and then convey them to vertical spike-picking roller to pick off the ear, the corn ear are conveyed to the spike collecting box by the delivery mechanism; Stalks are chopped by vertical hob behind the stem pulling roller , and then are casted by casting device to stem crushing box; and corn root are broken by counters-field device.

2.2. Technology Index of the Machine

According to the requirements of the chopping and ensiling craft of the corn stalks and the function characteristics of the prototype requirements, The main technical parameters are determined as is shown in Table 1.

Table 1. The main technical parameters of 4YQZ-3A combine harvester

Figure 1.4YQZ - 3 of maize united harvest machine structure schematic drawing

3. Main Working Parts Design

3.1 Gripping Delivery Mechanism

As figure 2 shows, gripping delivery mechanism are mainly made of positivefeeding chain, passive sprocket, tension device, clamping board, conveying chain and drive sprocket,etc. When the machine are working, milpa are devided and lifted up by nearsidedivider, and then drive sprocket are driven by passive sprocket and force feeding chain to run, so as to turn milpa to gripping delivery chains, In the meanwhile, cutterbar cut off the maize plants, the broken plants conveying chain and conveying dial gripping under the common function of bluegrass chain conveyor back into pick spike roller; Tension device is used to adjust the tensioner degree of the conveyor chain so as to make the clamping stalks of clamping conveying chain more stable and reliable.

3.1.1. Positivefeed Chain

Positivefeed chain is located below the nearsidedivider ,dedicated to cooperating with it to force-feed the corn plants with different Line spacing. The selection of the speed of positivefeeding chain have a great effect on plants clamping transmission. Excessive speed will make plants clamping feeding within the same lines, causing the phenomenon such as stem being cut off or jamed occur; however, the low speed may make the function of Feeding chain disapper.

Figure 2. Shetch of gripping delivery mechanism

1.positivefeeding chain 2. Passive sprocket

 3. Tensioningdevise 4. Gripping board 5. Conveyor chain

Theoretically, the speed of the positivefeeding chain, the level points speed should be equal to , ,the marching speed of the machine , but in actual work process, the influence factors of the speed of positivefeeding chain include: m v_ , thefront rake of positivefeeding chain, _ , aperture has forcedfeeding speed chain of Angle, before, and conditions, etc.In order not to make the machine push down the stem when it ismarching, the level points speed of the positivefeeding chain should be greater than ,the marching speed of the machine.

Figure 3. Velocity decomposition of conveying chain

3.1.2 Gripping Delivery Chain

While Gripping conveying chain is working, it is necessaryto ensure that the cutted plants are transported to spike pickingroller timely and reliable, and maintained a certain distance between the transported plants, to make spike picking roller load evenly.During Work, select maize plants to make velocity analysis in dot o in gripping chain, just as fig. 3shows.w v , its absolute velocity is induced as follows:

                                             (1)

                                 (2)

Where: the speed of gripping chain ;

And by:

                                 (3)

By type (2) and (3) we know that:

                                           (4)

Known by Type (4) ,While ,the absolute velocity,,point in the direction of clamping chain (bacward) and make Angle with horizontal line; While, Absolute speed and stalks will move forward a certain angle, which will go against conveying the corn plants smoothly. Combined with the performance testing of gripping conveying in the field , when the size of belongs to 10°〜20°，，this is the best situation.

3.2 Vertical Picking and Chopping Cutter

Vertical picking and chopping cutter is a critical component of picking both spike and stem , as shown In figure 4 , this device is mainlymade up of a Vertical spike picking roller, fixed knife, moving knife, Chopping cylinder.etc..

Figure 4. Vertical picking and chopping cutter

1.Vertical spike picking roller 2.Vertical stem pulling roller

3.Moving blade 4.The fixed knife 5.Chopping cylinder

3.2.1 The Scheme of Power Drive

The Scheme of Power Drive of Vertical picking and chopping cutter is shown in figure 5 .When it works, power driven by engine slow down to the input axis of chopped gearbox through the pulleys and double sprocket , the power drive shredding mechanism to run through a set of bevel gear; left behind the chop gearbox there are a group of driving chain (chainwheel of middle size and large size) transmit the power to spike picking chopped gearbox and then divide the power to stem pulling roller ear the bevel gear of the speed changing box; Above the stem pulling roller and spike picking are a group of driving chains, the power is transmitted from stem pulling roller to spike picking roller to pick the spikes. In The input axis of the spike picking gearbox lies the small chainwheel and pulley,it functions as transmitting the power to cluster transportation reciprocating type cutter.

3.2.2 Vertical Spike Picking Roller

Vertical spike picking is completed while corn ear are drooping, compared to the average Horizontal spike picking, the picked cluster can quickly break away from spike picking roller, greatly reduce the breakage rate and the loss rate of grain. In order to strengthen the ability stem pulling and spike picking, behind the spike picking roller are in pairs stem pulling roller , can pull stem while stalks, force feeding the stalks to hobbing cutter to chop,make the conveying of stalks unobstructed and not jam between the spike picking roller and hobbing cutter. The plane lies in the two Axis of vertical spike picking device and its vertical plane forerake the degree of 25°�35°, maize plants enter into verticalspike picking roller pick spike through grippingconveying feeding device by gripping. Plant in arc block under the effect of arc-shaped bluegrass board with picking spike into 50 °~ roller line 70 ° Angle. Due to the ascension of spike picking roller, between the plants of which spike are picked and spike picking roller there exist a vertical Angle and the plants are transported backward to chopping cylinder to chop.

Figure 5. sketch of power drive

1.Pulley 2.Big sprocket 3.Small sprocket 4.Spike picking gearbox

5.Chopping gearbox 6.Double sprocket 7.Middle sprocket

After plenty of indoor performance test, this design determines the diameter of vertical spike picking roller as 84mm,the speed of the spike picking roller is 1080r/min.

3.2.3 Chopping Cylinder

(1) the determination of the feeding entrance width

The productivity of the stalks chopping are calculated by the following type :

                                     (5)

Where: Q— Productivity of the design, the value is 30000kg/h;

Kc—Fill factor of the feeding stalks, the value is 0.6;

l—Chopping length, the values is 25mm;

—The numberof moving blade, and design the value for four pieces;

—Speed of mainshaft, and design the value for 2100r/min;

Yc—Unit weight of stalks after campaction, and design the value for400 kg/m3;

b —The feeding entrance length, design the value for 510mm.

Substitue the above data into the above type,we obtained: a = 1.96 mm , in this design we select a = 20mm.

(2) The determination of the chopping cylinder

The chopping cylinder diameter are obtained by the following type:

                                              (6)

                                             (7)

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