Blade and mower

Abstract

The application discloses a blade and a mower applying the same. The blade comprises a base extending in a radial direction of the blade and rotating around a first axis on the base; a cutting part extending outward from the base; and a raised part comprising a first raised part and a second raised part connected to each other, the first raised part being farther from the first axis than the second raised part. An included angle between a tangent at any point on a first edge line on an upper surface of the raised part and a first plane perpendicular to the first axis is an exit angle. In the radial direction of the blade, a change rate of the exit angle on the second raised part is greater than that on the first raised part.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lawn mowers, and in particular to a blade and a lawn mower. BACKGROUND

[0002] A lawn mower is a mechanical tool for trimming lawns, vegetation, etc. It is also known as a grass trimmer, a grass cutter, or a lawn trimmer. Existing lawn mowers mostly use rotating blades to cut grass. Some users use the lawn mower together with a grass collecting bag, so that the cut grass clippings can be absorbed into the grass collecting bag of the lawn mower for centralized storage, so as to facilitate centralized processing later. Some other users let the cut grass clippings fall freely, which serves as an organic fertilizer to provide nutrients for the lawn. SUMMARY

[0003] The purpose of the present application is to provide a blade and a lawn mower that can be applied to a lawn mower, and the purpose is to optimize the aerodynamic performance of the blade without increasing the rotational speed of the blade, so as to improve the grass cutting performance of the blade.

[0004] In order to achieve the above-mentioned purpose, the present application adopts the following technical solution: a blade suitable for a lawn mower, comprising: a base portion extending in the radial direction of the blade, the blade being arranged to be able to rotate about a first axis on the base portion when driven by the lawn mower; a cutting portion extending outward from the base portion; a raised portion comprising a first raised portion and a second raised portion connected together, the first raised portion being farther from the first axis than the second raised portion; characterized in that: the included angle between the tangent at any point on the first edge line of the upper surface of the raised portion and a first plane perpendicular to the first axis is an outlet angle, and in the radial direction of the blade, the rate of change of the outlet angle on the second raised portion is greater than the rate of change of the outlet angle on the first raised portion.

[0005] In one embodiment, the outlet angle continuously changes in the radial direction of the blade.

[0006] In one embodiment, in the radial direction of the blade, the length of the second raised portion is greater than the length of the first raised portion.

[0007] In one embodiment, in the radial direction of the blade, the rate of change of the raised length of the second raised portion is greater than the rate of change of the raised length of the first raised portion.

[0008] In one embodiment, the first boundary line of the raised portion projects onto the first plane to form a first curve, and the absolute value of the slope at any point on the first curve in the second raised portion is greater than the absolute value of the slope at any point on the first curve in the first raised portion.

[0009] In one embodiment, the path formed when transitioning from the root of the raised portion to the first edge line in the direction perpendicular to the radial direction of the blade is an arcuate curve.

[0010] In one embodiment, the raised portion further comprises a transition portion connected to the second raised portion and closer to the base portion than the second raised portion, the rate of change of the exit angle of the second raised portion in the radial direction of the blade being greater than the rate of change of the exit angle of the transition portion in the radial direction of the blade.

[0011] In one embodiment, the exit angle of the first raised portion is between 30° and 40°; the exit angle of the second raised portion is between 20° and 35°;

[0012] In addition, the present application also provides a mower comprising the blade as described above.

[0013] In one embodiment, the mower comprises an additional second blade in addition to the blade. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic view of a mower;

[0015] Figure 2 is a schematic view of a mower from a perspective in which the blade can be seen;

[0016] Figure 3 is a perspective schematic view of a blade suitable for use in the above-described mower;

[0017] Figure 4 is a schematic view of the above-described blade from another perspective;

[0018] Figure 5 is Figure 3 a front view of the blade shown;

[0019] Figure 6 is Figure 3 a top view of the blade shown;

[0020] Figure 7 is Figure 3 a schematic view of a portion of the blade shown in Figure 1 1 ;

[0021] Figure 8 is Figure 3 a right view of the blade shown in Figure 1 1 ;

[0022] Figure 9 is Figure 8 a partial enlargement of the raised portion in the right view of Figure 1 1 ;

[0023] Figure 10 is Figure 5 a partial enlargement of the front view shown;

[0024] Figure 11 is Figure 6 a partial enlargement of the top view shown;

[0025] Figures 12 to 17 is Figure 10 a side sectional view of six cutting positions in

[0026] Figure 18 is Figure 8 a partial enlarged view of the raised portion in the right view;

[0027] Figure 19 is Figure 7 a force analysis schematic diagram of the blade shown in

[0028] Figure 20 is Figure 7 a schematic diagram of an embodiment of the blade shown in

[0029] Figure 21 is Figure 7 a schematic diagram of another embodiment of the blade shown in DETAILED DESCRIPTION

[0030] In order to make the technical problems solved by the present application, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the embodiments of the present application will be further described in detail below with reference to the drawings. The described embodiments are only some of the embodiments of the present application, not all the embodiments.

[0031] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "front", "back" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for the purpose of description or for distinguishing different structures or components, and cannot be understood as indicating or implying relative importance.

[0032] The blade involved in the present application is generally applied to a mower, and a hand-pushable mower 10 will be taken as an example for description below. It can be understood that the mower can also be a riding mower.

[0033] The blades of a lawnmower are usually designed to include a cutting portion and a raised portion at an angle to the cutting portion, the cutting portion is responsible for cutting the grass to be cut, and the raised portion is responsible for forming a certain lift on the surface of the rotating blade, so that the grass clippings cut by the cutting portion move upward when affected by the lift, so that when the grass clippings fall, they can be cut again by the blade. The benefit of this is that grass clippings that have been cut twice are usually cut more finely than grass clippings that have only been cut once. We know that when larger grass clippings enter the grass collection bag, the grass collection bag is easily filled more quickly, but when the grass clippings are cut more finely, the fine grass clippings can more fully enter the space in the grass collection bag, thereby extending the use time of the grass collection bag, reducing the frequency at which the grass collection bag of the lawnmower needs to be emptied or replaced, and the finer grass clippings are also easier to decompose or dispose of as fertilizer. Therefore, whether the operator uses a grass collection bag or not, designers are pursuing a lawnmower blade that cuts grass clippings that are shorter and finer.

[0034] In order to achieve the above objective, some blades are designed to rotate at a higher speed, which on the one hand increases the lift formed by the rotation of the blade, so that the first cut grass clippings are lifted to a higher height, and on the other hand increases the frequency of the blade cutting the grass clippings, further ensuring that the grass clippings falling from a high place can be cut again by the rotating blade. However, operating the blade at a higher speed consumes too much energy, and the lawnmower needs more frequent energy supply, or affects the amount of grass that can be cut with the same amount of power or oil. At the same time, higher blade rotation speed makes the blade rotate produce more noise, which affects the user's experience.

[0035] Therefore, the applicant tries to increase the lift formed by the surface of the blade while maintaining a reasonable speed of the blade, so that the grass clippings that have been cut once can stay in the air for a longer time before falling to the ground, increasing the probability of being cut again, and thus the following technical solutions are generated.

[0036] As shown in Figure 1 and Figure 2 , the lawnmower 10 includes a handle 60, a chassis 20, wheels 40 and a blade 30, and the lawnmower 10 can also include a power source and a transmission mechanism, etc. The power source cooperates with the transmission mechanism to drive the wheels 40 to rotate and drive the blade 30 to rotate. As shown in Figure 2 , the blade 30 is located in the accommodating space formed by the chassis 20 and rotates around the rotation center 110 in the first rotation direction R. The lawnmower involved in the figure also includes a grass collection bag 50 mounted on the lawnmower 10, and the grass cut by the blade 30 enters the grass collection bag 50 through the grass discharge passage 21 on the chassis 20. The grass collection bag 50 is not essential to the lawnmower 10, and some users allow the cut grass to fall directly on the grass surface, and the cut grass is used as fertilizer again. Such operating habits do not affect the technical effects achieved by the blade in this application.

[0037] As shown in Figure 3 , the blade 30 comprises a base 200, a cutting part 300 and a raised part 400. The base 200 extends along the radial direction of the blade 30 to both sides and reaches the cutting part 300. The upper surface of the base 200 comprises a front boundary 201 and a rear boundary 202, both of which are substantially parallel to the radial direction of the blade in this embodiment. The cutting part 300 is the main working part of the blade 30 for cutting, and most of the cut objects are cut by the cutting part 300. The blade 30 further comprises at least one raised part 400, which is located at the end of the blade 30, and the raised direction of the raised part 400 is away from the cutting part 300. Figure 3 The shape of the raised part 400 can be more clearly seen from another perspective. Figure 4 The shape of the raised part 400 can be more clearly seen from another perspective.

[0038] Figure 5 and Figure 6 are schematic diagrams of the blade 30 when viewed from the front and top, respectively, of the blade 30 in the direction coordinates specified in Figure 3 , that is, Figure 5 is a front view of the blade 30, Figure 6 is a top view of the blade 30. The blade 30 rotates around the first axis 101 passing through the rotation center 110, and the cutting part 300 of the blade 30 is divided into a first cutting part 310 and a second cutting part 320. The first cutting part 310 is closer to the cutting surface of the cut object than the second cutting part 320, so when the blade 30 rotates, the first cutting part 310 can cut lower grass than the second cutting part 320. In this embodiment, the first cutting part 310 is substantially parallel to the base 200, and the second cutting part 320 has a certain curvature and is smoothly connected to the first cutting part 310 by the base 200.

[0039] In some embodiments, the front boundary 201 and the rear boundary 202 of the base 200 are not necessarily a single straight line, but can also be a curved line such as an arc or a combination of multiple straight lines such as a tooth shape. The shape of the base 200 is not the core of the present application, and hereinafter the common form of the base 200 in the prior art will be discussed, that is, the front boundary 201 and the rear boundary 202 of the base 200 of the blade 30 are substantially parallel to the radial direction of the blade 30.

[0040] As shown in Figures 3 to 6As shown, a first straight line 211 extending radially along the blade 30 is defined. This first straight line 211 passes through the rotation center 110 of the blade 30 and lies on the upper surface of the blade. A second straight line 212 substantially perpendicular to the radial direction of the blade 30 is defined. This second straight line 212 passes through the rotation center 110 of the blade 30 and lies on the upper surface of the blade. Here, the first straight line 211 and the second straight line 212 are substantially perpendicular. It can be understood that the blade 30 has a length direction and a width direction, the base 200 is substantially symmetrical about the first straight line 211, and also substantially symmetrical about the second straight line 212. The direction of the first straight line 211 is parallel to the length direction of the blade 30, and the direction of the second straight line 212 is parallel to the width direction of the blade 30.

[0041] The following is based on Figure 7 The following description uses a portion of the blade 30 as an example. The raised portion 400 includes a first raised portion 410 and a second raised portion 420 connected together, with the first raised portion 410 being farther from the first axis 101 than the second raised portion 420. The boundary lines of the first raised portion 410 and the second raised portion 420 extend substantially along the boundary lines of the first cutting portion 310 and the second cutting portion 320. It should be noted that the dashed lines in the accompanying drawings concerning the raised portion 400 are artificially added schematic lines to better show the various parts of the raised portion 400 and are not actual lines present in the blade 30. In the actual product, the various parts of the raised portion 400 transition smoothly and do not produce a clear outline that distinguishes the boundaries of each part. In the radial direction along the blade 30, the length of the second raised portion 420 is greater than the length of the first raised portion 410. The raised portion 400 may also include a transition portion 430 for transitioning from the second raised portion 420 towards the base 200.

[0042] A first plane 240 is defined, which is perpendicular to the first axis 101 and passes through the center point of the rotation center 110 of the blade 30. In this embodiment, the upper surface of the base 200 is located on the first plane 240, and the first cutting portion 310 of the cutting portion 300 is substantially parallel to the first plane 240.

[0043] When we follow Figure 7 When observing blade 30 from the right side in the specified directional coordinate system, the following is obtained: Figure 8 The right view of blade 30 shown. Figure 9 for Figure 8 A magnified view of the raised portion 400 in the image. The raised portion 400 forms two boundary lines on the upper surface of the blade, respectively... Figure 8 The first boundary line 441 and the second boundary line 442 are shown. The first boundary line 441 is located on the opposite side from the cutting portion 300 of the blade 30, that is... Figure 7The rear side in the designated direction coordinate, while the second boundary line 442 is located at the outermost edge of the insert 30 substantially perpendicular to the cutting portion 300.

[0044] As shown in Figure 9 the exit angle a is formed between a tangent line formed at a certain point on the first boundary line 441 of the upper surface of the raised portion 400 and the first plane 240 in a direction substantially perpendicular to the radial direction of the insert 200 (i.e. along the second straight line 212). Since the first cutting portion 310 is substantially parallel to the first plane 240, the angle between the tangent line formed at a certain point on the first boundary line 441 of the upper surface of the raised portion 400 and the plane in which the first cutting portion 310 is located is equivalent to the exit angle a defined herein, and a series of different exit angles a are formed from different points on the first boundary line 441. It is emphasized that the exit angle a is located on the surface of the raised portion 400 that is bent towards the cutting portion 300, i.e. the upper surface of the insert 30 in the present embodiment. Figure 9

[0045] Figure 9 The raised distance L of the raised portion 400 is also shown, which is the distance from the root of the raised portion 400 to the first boundary line 441. The raised root refers to the "boundary line" that passes through the transition from the cutting portion 300 to the raised portion 400. It is noted that the raised distance L refers to the surface of the raised portion 400 that is bent towards the cutting portion 300 and is close to the cutting portion 300, i.e. the upper surface of the insert 30.

[0046] Attention will now be drawn to Figure 10 and Figure 11 In order to better illustrate the technical features of the present application, Figure 10 and Figure 11 The front view and the top view of the insert 30 shown in Figure 5 and Figure 6 are respectively enlarged at one end, and a series of points are randomly selected on the first boundary line 441 of the raised portion 400, which are respectively: the first point 401 and the second point 402 on the first raised portion 410, the third point 403 and the fourth point 404 on the second raised portion 420, and the fifth point 405 and the sixth point 406 on the transition portion 430. The feature of this series of points is that the distance between the two points on each part of the raised portion 400 in the radial direction of the insert 30 is equal, i.e. the distance in the direction of the first straight line 211 is equal. That is, in the direction of the first straight line 211, the distance between the first point 401 and the second point 402 is equal to the distance between the third point 403 and the fourth point 404, and also equal to the distance between the fifth point 405 and the sixth point 406. Now "cut" the above six randomly selected points in the direction perpendicular to the radial direction of the insert 30, i.e. the second straight line 212, to form the following figures: Figures 12 to 17 ​six cross-sectional views along the six different cross-sectional planes A-A, B-B, C-C, D-D, E-E and F-F.

[0047] Figure 12 The cross-sectional view along A-A for the first point 401, the first point 401 forms a first lift distance LI and a first exit angle al. Figure 13 The cross-sectional view along B-B for the second point 402, the second point 402 forms a second lift distance L2 and a second exit angle a2. Figure 14 The cross-sectional view along C-C for the third point 403, the third point 403 forms a third lift distance L3 and a third exit angle a3. Figure 15 The cross-sectional view along D-D for the fourth point 404, the fourth point 404 forms a fourth lift distance L4 and a fourth exit angle a4. Figure 16 The cross-sectional view along E-E for the fifth point 405, the fifth point 405 forms a fifth lift distance L5 and a fifth exit angle a5. Figure 17 The cross-sectional view along F-F for the sixth point 406, the sixth point 406 forms a sixth lift distance L6 and a sixth exit angle a6.

[0048] For the six points randomly selected, the difference between the first exit angle al and the second exit angle a2 formed by the two points on the first lift portion 410 is about 3°, the difference between the third exit angle a3 and the fourth exit angle a4 formed by the two points on the second lift portion 420 is about 6°, and the difference between the fifth exit angle a5 and the sixth exit angle a6 formed by the two points on the transition portion 430 is about 2°. Since the two points on each portion are equidistant in the radial direction of the blade 30, for the six points, the rate of change of the exit angle a formed by the third point 403 and the fourth point 404 is greater than the rate of change of the exit angle a formed by the first point 401 and the second point 402, and the rate of change of the exit angle a formed by the third point 403 and the fourth point 404 is greater than the rate of change of the exit angle a formed by the fifth point 405 and the sixth point 406.

[0049] Specifically, in the present embodiment, the exit angle of the outermost side of the first lift portion 410 of the blade 30 is between 33° and 38°. Generally, the exit angle of the first lift portion 410 is between 30° and 40°, and the exit angle of the second lift portion 420 is between 20° and 35°.

[0050] However, the six points selected above are randomly selected to explain the characteristics of the raised portion 400 of the blade 30. For the blade involved in the present application, for any randomly selected point on the first boundary line 441, the following rule is met, that is, in the radial direction of the blade 30, the change rate of the outlet angle a of the second raised portion 420 is greater than the change rate of the outlet angle a of the first raised portion 410. Similar to the outlet angle a described above, the raised length L also has a similar rule, that is, in the radial direction of the blade 30, the change rate of the raised length L of the second raised portion 420 is greater than the change rate of the raised length L of the first raised portion 410.

[0051] In actual observation of the blade 30, the boundary line between the first cutting portion 310 and the second cutting portion 320 is not clear, and the boundary line between the first raised portion 410 and the second raised portion 420 is also not clear, but the overall change rule meets the above description. Therefore, when actually measuring the change rate of the outlet angle a, a segment with the same radial distance on the first raised portion 410 and the second raised portion 420 is randomly selected, and the size of the difference of the outlet angle a is measured to compare the size of the change rate of the outlet angle a. When selecting the segment, attention should be paid to avoiding points close to the virtual boundary line between the first raised portion 410 and the second raised portion 420, the second raised portion 420 and the transition portion 430 (i.e. the dashed line on the raised portion 400 in the figure), and selecting points similar to those in the area that can be clearly seen in Figure 11 .

[0052] It should be pointed out that the change rate of the outlet angle a and the change rate of the raised length L have no fixed size relationship between the first raised portion 410 and the transition portion 430. For the entire raised portion 400, the change rate of the outlet angle a and the change rate of the raised length L formed by the second raised portion 420 are greater than the change rate of the outlet angle a and the change rate of the raised length L formed by the first raised portion 410 and the transition portion 430.

[0053] As shown in Figure 18 , in the present embodiment, for each point on the first boundary line 441 on the blade 30, the outlet angle a formed thereby is only with respect to the air flow outlet orientation shown in Figure 18 , and when the raised length L is continuously transitioned to the outlet angle a from the root, the upper surface of the raised portion 400 of the blade 30 forms different angles, for example, β and γ in Figure 18 . In some embodiments, the upper surface of the raised portion 400 of the blade 30 forms different angles that are continuously changed. That is, the path formed when transitioning from the root of the raised portion 400 to the first edge line 441 in the radial direction perpendicular to the blade 30 is a curved line with a radius.

[0054] Figure 11 The shape of the first boundary line 441 of the raised portion 400 is also shown from the top of the blade 30. The shape of the first boundary line 441 of the raised portion 400, when projected on the first plane 240, is a first curve 443. The absolute value of the slope of the first curve 443 is greater at the second raised portion 420 than at the first raised portion 410. If the raised portion 400 also contains the transition portion 430, then on the upper surface of the blade 30, the absolute value of the slope of the first curve 443 is greater at the second raised portion 420 than at the first raised portion 410 or the transition portion 430.

[0055] Based on the special configuration of the raised portion 400 of the blade 30 described above, a series of technical effects are achieved. Figure 19 The approximate directions of the lift provided by the first raised portion 410 and the second raised portion 420 when the blade 30 is rotating are shown. It should be noted that, Figure 20 This is only a schematic diagram of the forces on the blade 30 and does not represent the exact size and direction. When the blade 30 is rotating, if only the work done by each part of the raised portion 400 is considered separately, without considering the influence of one part on the other two parts, the lift F1 formed by the first raised portion 410 is greater than the lift F2 formed by the second raised portion 420, and the lift F2 formed by the second raised portion 420 is greater than the lift F3 formed by the third raised portion 430. The benefits of this design are: on the one hand, the lift formed by the raised portion 400 gradually weakens from the first raised portion 410 to the second raised portion 420 and the third raised portion 430, preventing the lift of the entire raised portion 400 from being too large, causing the grass clippings to be deflected too much in the direction of the base of the blade 30 when being lifted, and causing some grass clippings to not contact the cutting portion 300 after falling; on the other hand, since the first cutting portion 310 of the cutting portion 300 is more deeply cut into the grass being cut, the cutting ability of the cutting portion 300 is mainly concentrated in the first cutting portion 310 during the first cutting. If the lift of the outer end of the blade 30 is too small, it is easy to cause a large amount of grass clippings to be unable to be lifted, or the grass clippings to fly towards the edge of the base 20, causing grass to be stuck or blocked, and other phenomena.

[0056] However, due to the first raised portion 410, the second raised portion 420 and the transition portion 430 being connected to each other, the air flow generated by each cutting portion of the blade 30 will affect each other when the blade 30 rotates, and by adjusting a series of variables such as the outlet angle a and the raised length L mentioned above, the entire blade 30 eventually exhibits a more appropriate cutting efficiency. The grass clippings cut by multiple cutting will be more easily spread throughout the grass catcher bag, reducing the frequency of the user replacing the grass catcher bag. And when the blade 30 involved in the present application is running, it does not need to run at a high speed, so as to achieve better aerodynamic performance, which on the one hand reduces the energy consumption of the blade 30 in the same working time, reduces the frequency of the user charging, replacing the battery, or refueling the engine; on the other hand, the noise caused by the rotation of the blade 30 is also reduced, which further enhances the user experience.

[0057] As shown in the drawings, Figure 20 In an embodiment, the raised portion 400 is cut at both ends or one end of the blade 30b to form a cutout 443, so that the surface of the rightmost edge of the first raised portion 410b forms an angle with the second straight line 212. This embodiment is beneficial to reduce the amount of grass clippings stuck in the lawn mower chassis 20.

[0058] As shown in the drawings, Figure 21 In an embodiment, the edge of the cutting portion 300c of the blade 30c forms an angle with the radial direction of the blade 30c, which can be considered as a certain "twist" of the cutting portion 300c of the blade 30c, but this will not change the characteristics of the raised portion 400c in the present application.

[0059] In addition, the blade 30 involved in the present application can also be applied to the case of two blades or even multiple blades stacked. For some blades 30, the second boundary line 442 of the transition portion 430 can also be deflected, or the boundary of the transition portion 430 can be designed as a notch 411, etc. instead of the smooth transition shown in the embodiments, but the first raised portion 410 and the second raised portion 420 are less affected and still meet the characteristics described above.

[0060] Through experiments, it has been verified that the blade involved in the present application has higher cutting efficiency than other blades with similar length, consumes less energy at the same speed, and has obvious advantages.

[0061] In an embodiment, the lawn mower 10 includes the blade 30, and further includes a second blade (not shown in the drawings). The second blade is an additional blade different from the blade 30, and the second blade can have the same structural features as the blade 30 or different structural features from the blade 30. The second blade can be arranged separately from the blade 30 to generate two cutting areas, or can be arranged in an up-down stacked manner with the blade 30, which is not limited herein.

[0062] The basic principles, main features and advantages of the present application are shown and described above. Those skilled in the art should understand that the above embodiments do not limit the present application in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation fall within the protection scope of the present application.

Claims

1. A blade for a mower, comprising: a base extending in a radial direction of the blade, the blade being configured to rotate about a first axis on the base when driven by the mower; a cutting portion extending outwardly from the base; a raised portion comprising a first raised portion and a second raised portion connected to each other, the first raised portion being further away from the first axis than the second raised portion; characterized in that: a tangent at any point on a first edge line of an upper surface of the raised portion forms an exit angle with a first plane perpendicular to the first axis, and a rate of change of the exit angle along the radial direction of the blade is greater on the second raised portion than on the first raised portion.

2. The blade of claim 1, wherein: the exit angle continuously changes along the radial direction of the blade.

3. The blade of claim 1, wherein: a length of the second raised portion is greater than a length of the first raised portion along the radial direction of the blade.

4. The blade of claim 1, wherein: a rate of change of a raised length of the second raised portion is greater than a rate of change of the raised length of the first raised portion along the radial direction of the blade.

5. The blade of claim 1, wherein: the first edge line of the raised portion projects onto the first plane to form a first curve, and an absolute value of a slope at any point on the second raised portion is greater than an absolute value of a slope at any point on the first raised portion.

6. The blade of claim 1, wherein: a path formed when transitioning from a root of the raised portion to the first edge line along a direction perpendicular to the radial direction of the blade is a curved line with a radius.

7. The blade of claim 1, wherein: the raised portion further comprises a transition portion connected to the second raised portion and closer to the base than the second raised portion, and a rate of change of the exit angle along the radial direction of the blade is greater on the second raised portion than on the transition portion.

8. The blade of claim 1, wherein: the exit angle of the first raised portion is between 30° and 40°, and the exit angle of the second raised portion is between 20° and 35°.

9. A lawnmower characterised in that: a mower comprising the blade of any one of claims 1 to 8.

10. The lawnmower as claimed in claim 9, characterized in that: the mower further comprises a second blade in addition to the blade.

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