CN201127184Y

CN201127184Y - Knife blade for lawn mower

Info

Publication number: CN201127184Y
Application number: CNU2007201882809U
Authority: CN
Inventors: 陶发亮
Original assignee: Lifan Industry Group Co Ltd
Current assignee: Lifan Technology Group Co Ltd
Priority date: 2007-11-22
Filing date: 2007-11-22
Publication date: 2008-10-08
Anticipated expiration: 2017-11-22

Abstract

A cutter blade for lawn mowers comprises an installation part, cutting edges and an air hoisting part. The installation part is positioned at the center part of the cutter blade, and radially extends outwards along an opposite direction to form two end part sections, and one side of each end part section is provided with the cutting edge, the other opposite side and the outer end side of the end part section bend upwards along a first folding line to form the air hoisting part. The cutting edges on two end part sections and the air hoisting part are distributed along a same spiral direction. The head end of the air hoisting part is positioned on the first folding line, the tail end bends downwards along a second folding line, and the bending part forms the gas flow source. The inner ends of the first and second folding lines are superposed. The back negative pressure of the air hoisting part is lowered by rotating the tailing edge flow flat gas flow sources of the cutting blade to reduce volution, and thus the noise generated by the rotation of the cutting blade is lowered. The cutting blade has the advantages of simple structure and low cost.

Description

The blade that is used for hay mower

Technical field

The utility model relates to a kind of mowing blade, specifically, is a kind of blade that is used on the hay mower.It finishes the rear portion that the grass bits of mowing operation and will cut are discharged into mower by the rotation of output shaft.

Background technology

At present, the blade that is used for the rotary type mower comprises that one is fixed to mounting portion on the engine output shaft and this mounting portion and stretches out along opposite direction and form two end sections, a limit of each end sections is for rotating leading edge, another relative limit is for rotating trailing edge, rotation leading edge on two end sections and rotate trailing edge and distribute by same rotation direction, described blade is arranged on and rotates on the leading edge, and blade is used for mowing by the leading edge of its rotation; Described rotation trailing edge is bent upwards and forms the air-lift unit part of inclination, and this air-lift unit partly is provided with the rotation trailing edge that extends along the back upper place with certain inclination angle, is used to produce the required air-flow of grass bits that discharge is cut off.With the air-flow separated into two parts, when the rotating speed of blade increased, will remove from this surface very soon after the air-lift unit part by lip-deep air-flow along the front surface of air-lift unit part and rear surface for blade.Rotate noise for reducing, normally partly be provided with a plurality of elongated ventilating openings, to reduce the negative pressure that produces at the rear of air-lift unit part at this air-lift unit.

For the rotary type mower, it partly is a kind of current techique that an air-lift unit that is used to discharge the grass bits of cutting is set on rotating blade.The existence of air-lift unit part will produce negative pressure (vacuum area) at the rear portion of air-lift unit part.This negative pressure makes airflow-reversing, thereby has produced the rotation noise.Rotate noise for reducing, this air-lift unit partly is provided with a plurality of above-mentioned elongated ventilating openings, to reduce the negative pressure that produces at the rear of air-lift unit part.But because blade is at high speed rotating, when air communication was crossed ventilating opening, air-flow and ventilating opening can produce resonance, uttered long and high-pitched sounds thereby can produce.

The utility model content

The purpose of this utility model is to provide a kind of can produce the air-flow that is enough to discharge the grass bits of cutting, and can reduce the mower blade that rotates noise.

For achieving the above object, the utility model provides a kind of blade that is used for hay mower, comprise the mounting portion, blade and air-lift unit part, described mounting portion is positioned at the core of blade, this mounting portion extends radially outwardly along opposite direction and forms two end sections, a limit of each end sections is provided with blade, outer distolateral being bent upwards along first broken line together of another relative limit and this end sections forms the air-lift unit part, blade on two end sections and air-lift unit partly distribute by same rotation direction, its improvements are: described air-lift unit part head end is positioned on first broken line, tail end is outwardly-bent along second broken line, form the gas flow source by this sweep, the inner of described first broken line and second broken line overlaps.

Blade of the present utility model according to the gas flow principle, will produce negative pressure (vacuum area) at the rear portion of blade air-lift unit part when rotating.Because negative pressure produces noise, therefore partly be provided with a gas flow source, to reduce negative pressure at air-lift unit.The mobile flat that rotates trailing edge reduces negative pressure, with the minimizing spiral flow, thereby reduces the noise that is produced by the rotation of blade.

In order further to reduce the noise that produces by the rotation of blade, it is radius R that the utility model adopts lower end, center E and upper end, center F with blade with the outer end of blade, adopting this technical scheme is in order to reduce the centrifugal force of blade outer end, when avoiding blade lengths longer, owing to the two ends up-down vibration of blade produces noise.In order to make the end of noise that blade rotation produces, above-mentioned air-lift unit part is 35 degree～45 degree with the angle α on plane, described blade place, and the angle β on described gas flow source and plane, described blade place is that 3 degree～8 are spent; The outer distolateral width of above-mentioned air-lift unit part is 2/5 to 3/5 of a blade width, and the outer distolateral width of above-mentioned gas mobile source is 1/10 to 3/20 of a blade width.

During blade rotation of the present utility model, because the length of blade is greater than the lateral length of air-lift unit part, and the air-lift unit parts of sloping portion are to rotating leading-edge droop, form a backflow, make the bits that grow grass that will cut off carry out second time or repeatedly cutting, thus the grass of arrive discharging bits evenly, improve the careless and increase grass catcher volume amount of filling of the receipts of discharging the grass bits.

Beneficial effect: the utility model is outwardly-bent with the rotation trailing edge of the air-lift unit part of rotary type mower blade, form the gas flow source of the flat that flows, the mobile flat of this rotation trailing edge reduces the negative pressure of air-lift unit part back, to reduce vortex, thereby reduced the noise that produces by the rotation of blade, and the utlity model has advantage simple in structure, that cost is low.

Description of drawings

Fig. 1 is the stereogram that is installed in the blade of the utility model on the hay mower;

Fig. 2 be hay mower along arrow among Fig. 1 " A " to view;

Fig. 3 be hay mower along arrow among Fig. 1 " B " to view;

Fig. 4 is the vertical view of the blade of the utility model;

Fig. 5 be the utility model along B-B among Fig. 4 to view;

Fig. 6 is an end view of the present utility model;

Fig. 7 is the zoomed-in view of blade of the present utility model, air-lift unit part and gas mobile source;

Fig. 8 is the utility model and improves the contrast chart of the noise level of preceding contrast blade about rotating speed (rpm);

Fig. 9 A and Fig. 9 B are the utility model and the air-flow comparison diagram that improves preceding contrast blade;

Embodiment

Further the utility model is illustrated below in conjunction with drawings and Examples:

At first, with reference to Fig. 1, Fig. 2 and Fig. 3, shown in the figure hay mower that uses the blade of the utility model.The hay mower 10 that illustrates in this example is by the self-propelled hay mower that engine 11 is installed, and this engine 11 can make blade 20 rotate and drive two rear wheels 12.Engine 11 is installed on the base assembly 13, and blade 20 is fixed on the output shaft 14 of engine 11, is transferred torque to by engine 11 blade 20 is rotated, and enters in the grass catcher 15 to finish to mow operation and will cut off the grass bits that get off.

Two front vehicle wheels 16 are installed on the base assembly 13, and two front vehicle wheels 16 and two rear wheels 12 are regulated hay mower 10 by height regulating handle 17 adjusting height is installed on the base assembly 13 of hay mower 10.Thereby between ground G and blade 20, form certain distance, when cuing off grass, can regulate the height of mowing according to different purposes.

Handrail combination 30 is installed in base assembly 13 rear portions along on the position of rear extension, can collect the rear portion that careless grass catcher 15 of considering to be worth doing hangs over base assembly 13 for one, but the rear portion that the cover plate 18 that can cover on grass catcher 15 also covers at base assembly 13 simultaneously opening/closing.

Handrail combination 30 comprises handrail 31, time handrail 32, brake handle 33, handle 34, choke handle 35 and link up with 36 voluntarily.Brake handle 33 is held, regulated the closed throttle that the choke handle makes

carburetor

19,11 work of piloting engine of pulling starting rope 37.When holding voluntarily handle 34 again, 10 of hay mowers voluntarily to overtake.

With reference to Fig. 3, blade 20 rotates along the direction shown in the arrow " C ", thereby produces the air-flow shown in the arrow " D " in base assembly 13, the grass bits will be collected in the grass catcher 15 like this.

Below, with reference to Fig. 4, Fig. 5, Fig. 6 and Fig. 7 the structure of the blade of the utility model is illustrated.

Blade 20 comprises mounting portion 40, blade 24 and air-lift unit part 22, described mounting portion 40 is positioned at the core of blade 20, be installed on the output shaft 14 by insert adapter 21 mounting portion 40, this mounting portion 40 extends radially outwardly along opposite direction and forms two end sections, be rotation leading edge 23 on the limit of each end sections, this rotation leading edge 23 is provided with blade 24, outer distolateral being bent upwards along first broken line 8 together of another relative limit and this end sections forms air-lift unit part 22, blade 24 on two end sections and air-lift unit part 22 distribute by same rotation direction, by air-lift unit part 22 upwards guiding cut off the grass bits that get off by blade 24, air-lift unit part 22 is 35 degree～45 degree with the angle α on plane, blade 24 place, and the outer distolateral width of air-lift unit part 22 is 2/5 to 3/5 of a blade width; Described air-lift unit part 22 head ends are positioned on first broken line 8, tail end is outwardly-bent along second broken line 9, form gas flow source 26 by this sweep, the inner of described first broken line 8 and second broken line 9 overlaps, gas flow source 26 is 3 degree～8 degree with the angle β on plane, described blade 24 place, the outer distolateral width in gas flow source 26 is 1/10 to 3/20 of a blade width, and gas flow source 26 has reduced in the negative pressure (vacuum area) of air-lift unit part 22 in the blade rotary course.

In order further to reduce noise, lower end, the center E that the outer end, right side of blade 20 is arranged on blade 20 is on the circle in the center of circle, upper end, the center F that the outer end, left side of blade 20 is arranged on blade 20 is on the circle in the center of circle, reduced the centrifugal force of blade 20 outer ends like this, help overcoming blade two ends generation up-down vibration when blade lengths is long, thereby produce the problem of noise.

The blade 24 of blade 20 produces a difference L with the lateral length of air-lift unit part 22, and the difference L that edge length L2 and air-lift unit partial-length L1 produce, make blade 20 in rotary course, negative pressure by 22 generations of air-lift unit part, form a backflow, and the bits that grow grass that the cutting edge on the difference L will be cut off carry out the second time or repeatedly cut, and the grass of discharging is considered to be worth doing evenly, the careless and increase grass catcher volume amount of filling of receipts that grass is considered to be worth doing is discharged in raising thereby arrive.

The mounting portion 40 of blade 20, by installing hole 41 and peace position groove 42 that insert adapter 21 is fixing, and pass installing hole 41 and insert adapter 21 is installed on the output shaft 14 with bolt.Reference numeral 43 is illustrated in and reinforces a ribs on the blade 20.

As mentioned above: blade 20 has reduced the negative-pressure vacuum zone in blade 20 rotary courses in the gas flow source 26 that air-lift unit part 22 is provided with, make the negative pressure of air-lift unit part 22 generations and weakened spiral flow; At the difference L of edge length L2 and air-lift unit partial-length L1 generation, make the bits that grow grass that cut off carry out the second time or repeatedly cutting, consider to be worth doing evenly thereby arrive the grass of discharging; When being radius R, reduce the centrifugal force of outer end 27 with lower end, center E and upper end, center F.So just limited the rotation noise of blade 20, thereby reduced the noise that produces when rotating by blade 20.

Below, with reference to Fig. 8, Fig. 9 A and Fig. 9 B the working condition of the blade of the utility model is illustrated.

Fig. 8 points out the gas flow source 26 and the concern chart of contrast blade 80 about noise (dB) and rotating speed (rpm) that the blade 20 of the utility model is provided with, and noise is meant the acoustic pressure that the noise tests test method by BS EN 836:1997 appointment is recorded by rotary speed property.

The noise of blade 20 and blade 80 is linear increasing with the increase of rotating speed (rpm).The rated speed of hay mower also is that only rotating speed is 3000rpm.At rotating speed is that the noise of the utility model blade 20 is 95.7dB in the contrast of the present embodiment of 3000rpm and comparison example, and the noise of comparison example is 97.7dB.In other words, compare with comparison example blade 80, the blade 20 that is provided with gas flow source 26 has more effectively reduced rotation noise 2.0dB.

With reference to Fig. 9 A and Fig. 9 B the air-flow of the blade 80 of blade 20 of the present utility model and comparison example is illustrated.Fig. 9 A shows comparison example, and wherein Fig. 9 A (b) is the view along direction shown in the arrow " b " of Fig. 9 A (a).Fig. 9 B shows present embodiment, and wherein middle Fig. 9 B (b) is the view along direction shown in the arrow " b " of Fig. 9 B (a).

In Fig. 9 A (a), by direction of arrow G represent air-flow that comparison example blade 80 produces in rotation process by arrow 1., 3. 2. arrow represent with arrow.1. arrow is the air-flow by the top generation of blade 80, and 2. arrow represents the air-flow by the rear generation of blade 80.

In Fig. 9 A (b), air flow stream was crossed the rotation trailing edge 85 of blade 80 tops when blade 80 rotated, and 1. this air-flow is represented by arrow; Air flow stream is crossed blade side's after 80s rotation trailing edge 85, and 2. this air-flow is represented by arrow.But 2. arrow represents that air-flow has increased the negative pressure of rotation trailing edge 85 at the rear of blade 80, thereby has produced the spiral flow of 3. being represented by arrow, and the rotation noise that is produced is increased.

In Fig. 9 B (a), by direction of arrow G represent air-flow that comparison example blade 20 produces in rotation process by arrow 1., 3. 2. arrow represent with arrow.1. arrow is to pass through the air-flow that gas flow source 26 produces by the top of blade 20, and 2. arrow is represented to pass through the air-flow that gas flow source 26 produces by the rear of blade 20.

In Fig. 9 B (b), air flow stream was crossed air-lift unit part 22, the gas flow source 26 of blade 20 tops and is rotated trailing edge 25 when blade 20 rotated, and 1. this air-flow is represented by arrow; Air flow stream is crossed blade side's after 80s gas flow source 26 and is rotated trailing edge 25, and 2. this air-flow is represented by arrow.But 2. arrow represents that air-flow has reduced the negative pressure of rotation trailing edge 25 on the gas flow source 26 of blade 20, thereby has produced the spiral flow of 3. being represented by arrow, has so just reduced the rotation noise.The difference L that the blade 24 of blade 20 and air-lift unit part 22 produce and the negative pressure of air-lift unit part 22 generations, form a backflow, and the bits that grow grass that the cutting edge on the difference L will be cut off carry out the second time or repeatedly cut, and the grass of discharging is considered to be worth doing evenly, the careless and increase grass catcher volume amount of filling of receipts that grass is considered to be worth doing is discharged in raising thereby arrive.

Claims

1. blade that is used for hay mower, comprise mounting portion (40), blade (24) and air-lift unit part (22), described mounting portion (40) is positioned at the core of blade (20), this mounting portion (40) extends radially outwardly along opposite direction and forms two end sections, a limit of each end sections is provided with blade (24), outer distolateral being bent upwards along first broken line (8) together of another relative limit and this end sections forms air-lift unit part (22), blade (24) on two end sections and air-lift unit part (22) distribute by same rotation direction, it is characterized in that: described air-lift unit part (22) head end is positioned on first broken line (8), tail end is outwardly-bent along second broken line (9), form gas flow source (26) by this sweep, the inner of described first broken line (8) and second broken line (9) overlaps.

2. the blade that is used for hay mower according to claim 1, it is characterized in that: the outer end, right side (27 ') of described blade (20) is on the circle in the center of circle at lower end, the center E with blade (20), and the outer end, left side (27) of this blade (20) is on the circle in the center of circle at upper end, the center F with blade (20).

3. the blade that is used for hay mower according to claim 1, it is characterized in that: described air-lift unit part (22) is 35 degree～45 degree with the angle α on described blade (24) plane, place, and described gas flow source (26) is 3 degree～8 degree with the angle β on described blade (24) plane, place.

4. the blade that is used for hay mower according to claim 1 is characterized in that: the outer distolateral width of described air-lift unit part (22) is 2/5 to 3/5 of a blade width; The outer distolateral width in described gas flow source (26) is 1/10 to 3/20 of a blade width.

5. the blade that is used for hay mower according to claim 1 is characterized in that: be provided with ribs (43) on described mounting portion (40).

6. the blade that is used for hay mower according to claim 1 is characterized in that: the length of described blade (4) is greater than the lateral length of air-lift unit part (5).