JP5167987B2 - Lawn mower - Google Patents

Description

  The present invention relates to a lawn mower that cuts turf by rotating a rotary blade.

  2. Description of the Related Art Conventionally, lawn mowers that cut grass are widely used that use an electric motor or an internal combustion engine as a drive source, and those that have a rotary blade or a reel blade as the cutting means. FIG. 9 is a cross-sectional view showing the structure of a conventional rotary lawn mower, and FIG. 10 is a schematic view of a grass collecting fan attached to the lawn mower of FIG. FIG. 11 is a diagram for explaining a lawn mower according to the prior art and how to use it. In FIG. 11, the lawn mower 1 has a motor 3 as a drive source mounted inside a housing 2, and a cutter 7 is rotatably attached to the bottom of the housing 2 by the motor 3. The housing 2 accommodates a motor, and wheels 12, a handle 11, and a grass collection bag 13 are attached around the motor 2. When the operator turns on the switch for supplying electric power to the motor 3 while holding the handle 11, the cutter 7 rotates, and in this state, the handle is pushed in the moving direction to move the lawn mower body, (Hereinafter, the present specification will be described by defining the position where the worker is located with respect to the lawn mower body as the rear and the opposite as the front. Down, the opposite is up).

  The lawn mowing will be described with reference to FIG. 9. The lawn that has entered the housing through the opening of the wind tunnel outer wall 5 a by the forward movement of the lawn mower 1 is trimmed by the rotating cutter 7. The cut turfgrass rides in the horizontal air flow 10b created by the grass collecting fan 4 attached to the motor shaft 3a, is carried along the wind tunnel outer wall 5a, and is carried in the wind tunnel 5 and is attached to the discharge port 2a. Collected in the grass bag 13. However, in the conventional structure, an air flow toward the lower side of the wind tunnel outer wall 5a of the wind tunnel 5 is easily formed by the grass collecting fan 4, and the turfgrass riding on the horizontal air flow 10b is the lawn mower 1. However, there was a problem that the grass was not collected by the bucket for grass collection.

  In such a lawn mower, it is necessary to place the turf grass on the air flow and collect it in the grass collection bag 13 so as not to drop the cut grass. In response to this requirement, a method of generating an air flow upward in the wind tunnel so that the wind generated by the grass collecting fan does not go in the opening direction has been considered.

Japanese Utility Model 1-16732

  In the lawn mower in Patent Document 1, by providing an edge that guides the flow of wind on the outer peripheral portion of the rotor, the air kicked by the rotor blades is blocked by the edge of the rotor and changes the direction of the skirt upward. As a result, a negative pressure is generated between the rotor and the skirt, and the cut grass can be efficiently sucked into the body.

  However, in the technique of Patent Document 1, when a disc-shaped cutter having a larger outer diameter than the fan for collecting grass is used, an area where no wind flows in the horizontal direction of the fan for collecting grass is formed, so that the cutter and the fan for collecting grass are formed. A problem arises that turfgrass accumulates during the period. Furthermore, in the lower area of the passage connecting the grass collecting fan and the grass collecting bag, the wind flow becomes a poor accumulation area, so that the turf grass accumulates in the lower area without reaching the grass collecting bag. It becomes a factor of internal clogging (B in FIG. 9).

  The present invention has been made in view of the above background, and an object of the present invention is to provide a lawn mower that reduces the labor of maintenance due to accumulation of turfgrass and improves grass collection efficiency.

  Of the inventions disclosed in the present application, typical features will be described as follows.

  According to one aspect of the present invention, a main body having a discharge portion to which a bag for collecting grass can be connected, a drive source housed in the main body, a rotary blade that rotates in conjunction with rotation of the drive source, and A fan for collecting grass, and a wind tunnel that is located between the fan for collecting grass and the discharge unit and through which the fan wind passes, and the rotary blade has a larger rotating outer diameter than the fan for collecting grass, In the lawn mower having a grass collecting fan positioned above the rotary blade, a guide unit that blows a part of the fan wind obliquely upward to the grass collecting fan, and a part of the fan wind is a fan. A horizontal air passage for blowing air in the radial direction is provided.

  The guide part is constituted by a protrusion provided integrally on a base of the grass collecting fan, for example.

  For example, the guide portion is configured by being independently arranged between any blade of a plurality of blades arranged substantially radially on the grass collecting fan and the blade adjacent to the blade. Is done.

  According to the first aspect of the present invention, the grass collecting fan is provided with the guide portion that blows a part of the fan wind obliquely upward and the horizontal air passage that blows a part of the fan wind in the radial direction of the fan. As a result, it is possible to create an updraft and to discharge the air radially from the center of the fan, so that the turf grass cut off on the outer periphery of the fan can be prevented from collecting and the grass collection efficiency can be improved. . Furthermore, the airflow that flows out in the horizontal direction makes it possible to push turf grass spilled into the bottom from the downstream of the wind tunnel to the discharge port and improve the grass collection rate.

  According to the second aspect of the present invention, since the protrusion is disposed between the blades on the outer peripheral portion of the grass collecting fan, a passage that forms an air flow in the radial direction of the fan is formed between the blade and the protrusion. be able to. The direction of travel of the air flow formed by the blades is changed upward by the protrusions, and the turf grass cut by the cutter can be moved upward. This makes it easy to carry to the grass collection bag without spilling turfgrass that has been cut by the airflow.

  According to the third aspect of the present invention, the guide portion is formed by the protrusion provided on the base of the grass collecting fan, so that the turf grass can be guided upward with a simple configuration.

  According to the invention of claim 4, the guide portion has an inclined surface that becomes higher radially outward from the rotation center of the rotary blade and the fan for collecting grass, and from the center portion of the fan for collecting grass. It is possible to smoothly guide the flowing air flow obliquely upward.

  According to the fifth aspect of the present invention, the rotary blade has a larger rotation outer diameter than the fan for grass collection and the inner diameter of the wind tunnel is larger than the rotation outer diameter of the rotary blade. When the cut turf grass is carried obliquely upward by the air flow, the cut grass can be carried to the grass collection bag without spilling from the lawn mower body.

  According to the invention of claim 6, at least the lower part of the cylindrical outer peripheral wall constituting the wind tunnel as viewed from the fan and on the opposite side of the bag for collecting grass approaches the rotation center of the rotary blade and the fan for collecting grass as it goes downward. By providing the inclined portion inclined in the direction, the airflow flowing in the substantially horizontal direction from the grass collecting fan can collide with the lower portion of the outer peripheral wall, and then the airflow can be changed in the upward direction.

  The above and other objects and novel features of the present invention will become apparent from the following description and drawings.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view in which a lawn mower body according to an embodiment of the present invention is divided in the traveling direction, and FIG. 2 is a transverse sectional view in which the lawn mower body according to the embodiment of the present invention is divided in the traveling direction. The overall configuration of the lawn mower 1 is the same as that described above with reference to FIG.

  The internal structure of the lawn mower 1 will be described using the cross-sectional view shown in FIG. A motor 3 is accommodated inside the housing 2 of the lawn mower 1 so as to fit into a cylindrical motor case 2c provided on the upper plate 2b. Here, the motor 3 is arranged such that the motor shaft 3a is perpendicular to the ground. The housing 2 has a space called a wind tunnel 5 formed therein by an upper plate 2b and a wind tunnel outer wall 5a, which will be described later, and the motor case 2c is used for cooling the motor 3 from the upper space of the upper plate 2b toward the wind tunnel 5. An air passage is formed.

  The motor shaft 3a extends to the vicinity of the lower end of the housing, and a disk-shaped cutter 7 is attached below the motor shaft 3 so as to be rotatable in parallel with the ground. A grass collecting fan 4 is attached to the same motor shaft 3a so as to closely overlap the cutter 7. There is a relatively small gap between the grass collecting fan 4 and the motor case 2c. A bottom plate 9 is attached to the lower surface of the housing 2 so as to cover the discharge port 2 a side of the cutter 7 when viewed from the bottom so that the user does not touch the cutter 7. It is supposed to be exposed.

  An opening is provided at the lower end of the wind tunnel outer wall 5a on the front side in the traveling direction, and the opening is formed between the left front wheel and the right front wheel, and the upper end is positioned above the rotation surface of the cutter 7. . Moreover, the wind tunnel cover 15 (FIG. 11, FIG. 10) inclined so that a diameter may become small toward the lower side is attached to the lower part of the wind tunnel outer wall 5a so that attachment or detachment is possible. The wind tunnel cover 15 has a substantially semicircular shape along the wind tunnel outer wall 5 a, and the height of the lower end of the wind tunnel cover 15 from the ground is formed such that the upper end is located above the rotation surface of the cutter 7. .

  The axle that connects the left and right sides of the front wheel 12 a can be attached to the housing 2 at a different position. Thereby, the height of the rotating surface from the ground of the cutter 7 attached to the housing 2 can be changed, and the length of the grass to be cut can be adjusted.

  A discharge port 2a is formed at the rear of the housing 2, and a grass collection bag is attached so as to cover the discharge port 2a. The passage connected from the wind tunnel outer wall 5a to the discharge port 2a is formed so as to expand gently, and the upper portion of the passage is formed by a curve curved upward by the upper plate 2a. Further, the lower portion of the passage is connected to the discharge port 2a so as to incline upward in order to send the air flow from the grass collecting fan 4 that has passed around the motor case 2c to the grass collecting bag 13. Forms a recess for accommodating a part of the rear wheel outside the housing 2.

  In FIG. 2, the housing 2 is formed with a substantially spiral wind tunnel 5 from the wind tunnel outer wall 5a to the discharge port 2a. In other words, the housing 2 is centered on the motor shaft 3a with the position A of the motor shaft 3a in FIG. Rotate clockwise, rotate with the same passage width so that the center of the passage is at the same distance to the position of B, the center of the passage is away from the motor shaft 3a from the position of B to the position of C, and discharge from the position of C The passage width is expanded and connected so that turf grass is discharged in the tangential direction to the center point of the outlet 2a. Further, since the upper plate 2b is gradually increased from the position A to the position C, it is directed toward the discharge port 2a while increasing the cross-sectional area of the wind tunnel.

  A cutter 7 is attached to the motor shaft 3a. The outermost diameter of the cutter 7 is smaller than that of the wind tunnel outer wall 5a, and a gap is provided in the radial direction between the cutter 7 and the wind tunnel outer wall 5a. Similarly, the outer diameter of the grass collecting fan 4 mounted on the motor shaft 3a is about 70% smaller than the outermost diameter of the cutter 7, and the outer diameter of the cylindrical motor case 2c is about 4%. The cutter 7 and the grass collecting fan 4 are exposed in the wind tunnel 5 from the motor case 2c in the radial direction.

  In FIG. 3, the grass collecting fan 4 is formed by integral molding, has a disk-shaped base 14, and has an attachment hole for attaching the grass collecting fan 4 to the motor shaft 3 a at the center. The area around the mounting hole of the grass collecting fan 4 protrudes from the base 14 to the upper surface side, forms a concave shape when viewed from the lower surface side, and is clamped by bolts via an attachment member having a shape adapted to the concave shape. 7 and fixed integrally.

  On the upper surface side of the base 14 of the grass collecting fan 4, a plurality of blades 4 a extending substantially radially about the mounting hole are provided by integral molding with the base 14. The blades 4a are connected so that the inner diameter side is at the same height as the protrusions in the vicinity of the mounting hole, and are gradually increased in the outer diameter direction. The blades 4 a are formed with a substantially constant width from the inner diameter side to the outermost diameter side of the grass collecting fan 4. A protrusion 4b independent of the blade 4a is provided between the blade 4a on the base 14 and the adjacent blade 4a, and a passage 4c is formed between the blade 4a and the protrusion 4b. The protrusion 4b is disposed on the outer peripheral side of the base 14, and the curved surface 4d on the inner diameter side forms a concave curved surface so as to smoothly move upward from the inner peripheral side of the grass collecting fan 4 toward the outer peripheral side. The maximum height is formed lower than the blade 4a. The protrusion 4b has a shape that is connected to the passage 4c while being inclined in the circumferential direction. Further, the protrusion 4b can be easily formed by integral molding with the base 14 like the blade 4a.

  In FIG. 11, the wind tunnel cover 15 has a substantially semicircular shape, an attachment surface 15a having an attachment portion 15c for attachment to the housing 2, and an inclination in which the diameter of the arc shape gradually decreases toward the lower end. Part 15b.

  In FIG. 10, the air flow 10b carrying turfgrass flows toward the wind tunnel cover 15 below the wind tunnel outer wall 5a, but the air flow 10b colliding with the vicinity of the lower end of the wind tunnel cover 15 moves away in the upward direction. The air is smoothly guided upward by the inclined portion that is inclined, and is changed to the upward air flow 10c.

  Next, the operation of the embodiment according to the present invention will be described.

  In FIG. 1, the operator operates a switch (not shown) while holding the handle 11 to supply power to the motor 3, the motor shaft 3a rotates, and the cutter 7 attached to the motor shaft 3a rotates to rotate the turf grass. Reap. Since the grass collecting fan 4 is mounted coaxially with the mounting shaft of the cutter 7, the grass collecting fan 4 is rotated by the motor shaft 3 a and the air in the motor case 2 c is sucked from the central portion of the grass collecting fan 4 to the outer edge portion. Generate an air flow that heads.

  The cut turfgrass is carried by the air flow 10a, 10b created by the grass collecting fan 4 attached to the motor shaft 3a. Reference numeral 10a denotes a flow formed by a curved surface 4d provided on the protrusion 4b on the outer peripheral portion provided on the grass collecting fan 4. Further, 10b passes through the passage 4c between the projection 4b on the outer peripheral portion disposed on the grass collecting fan 4 and the blade 4a, and a wind flow is formed substantially horizontally in the radial direction.

  Most of the cut turfgrass rides upward airflow 10a, winds up upward, is blown toward the inside of the wind tunnel 5, is carried along the wind tunnel outer wall 5a, and is carried in the wind tunnel 5 and attached to the discharge port 2a. Collected in a collection bag.

  According to such a configuration, the wind flow of the grass collecting fan 4 is changed upward by the curved surface 4d, and a part of the air flow 10b is discharged in a substantially horizontal direction, so that the air flow 10b becomes the outer periphery of the protrusion 4b. The turfgrass goes around and cleans the turf grass, and the turfgrass accumulation due to the pressure drop can be suppressed at the outer periphery of the protrusion 4b, and the grass collection rate can be improved. In addition, the air flow discharged in a substantially horizontal direction makes it possible to push turf grass that has spilled from the downstream of the wind tunnel into the bottom of the discharge port into the bag for collecting grass, thereby suppressing clogging of the grass and further increasing the grass collection rate. Can be improved.

  Further, since the cross-sectional area corresponding to the increase in the air volume around the rotation direction of the grass collecting fan 4 from the position A to the position C connected to the discharge port 2a, the resistance is small and the position A As a result of the difference in height between the positions C and C, the air flowing from the position C to the position A in the rotation direction can be suppressed, and a flow from the position C to the discharge port 2a can be formed.

  Further, by providing a sufficient gap in the radial direction and the axial direction between the cutter 7 and the lower end of the wind tunnel outer wall 5a, the turf grass cut by the cutter 7 can be put on the airflow without dropping out of the housing 2. Can do.

  Further, in the grass collecting fan 4, the blade 4a is connected to the central portion and formed so as to be gradually raised toward the outer diameter direction, so that the lawn mower 1 avoids interference with the motor case 2c on the inner peripheral side. It is possible to obtain an effect of drawing air in the vicinity of the inflow port while keeping the overall height of the airflow low and to obtain a sufficient air volume on the outer peripheral side. Further, by arranging a protrusion having an inclined surface inclined upward from the inner peripheral side toward the outer peripheral side on the outer peripheral side of the grass collecting fan 4, an upward air flow can be formed, and the grass collection rate Will improve.

  In addition, since the blades 4a and the protrusions 4b are independently arranged on the base 14, it is possible to form a blowing path to the outer peripheral side without providing resistance on the side portion of the blade 4a where air flow is likely to occur. Thus, the air flow in the horizontal direction can be discharged to the outer periphery of the grass collecting fan 4 while suppressing the decrease in the air volume and the generation of noise.

  Further, the curved surface 4d on the inner diameter side is formed such that the maximum height of the protrusion 4b is lower than that of the blade 4a, so that the protrusion 4b becomes resistance to the air flow from the inner peripheral side to the outer peripheral side of the grass collecting fan 4. This can be suppressed and a sufficient air volume can be obtained. Further, the protrusion 4b is connected to the passage 4c while being inclined in the circumferential direction, has a substantially trapezoidal shape as viewed from the outer edge side, and is cut by airflow through a horizontal air passage formed in the grass collecting fan 4 Noise such as sound can be suppressed.

  In addition, by forming an inclined portion that is inclined in a direction in which the diameter decreases downward at the lower portion of the wind tunnel outer wall 5a, the air flow 10b flowing toward the lower portion of the wind tunnel outer wall 5a hits the wind tunnel cover 15 and faces upward. Is changed to an upward air flow 10 c and reaches the grass collection bag 13 via the wind tunnel 5. As a result, the turf grass cut off is less likely to leak out of the lawn mower 1 and is efficiently collected in the grass collection bag.

  In addition, the wind tunnel cover 15 is provided so as to be detachable from the housing 2 so that the operator can select the use of the wind tunnel cover 15 and the housing 2 is configured in a shape that can be easily molded. Can do.

  The slope 4d provided on the grass collecting fan 4 is a curved surface in the embodiment, but the object can be achieved even in a planar shape.

  Further, the shape of the grass collecting fan 4 is not limited to that shown in FIG. 3, and even if the projections have a rectangular cross section as shown in FIGS. A plurality of protrusions 4b may be provided therebetween.

  Furthermore, the blades 4a do not have to be linear in the radial direction, and may be blade-shaped fans having a curvature.

  Further, the wind tunnel cover 15 may be attached to the housing 2 in any way as long as it does not fall off during work. The wind tunnel cover 15 may be attached with bolts, or provided with uneven shapes on the cover side and the housing side. Various methods can be applied. Furthermore, if the mounting height of the wind tunnel cover 15 with respect to the housing 2 can be changed according to the target turf grass, work environment, etc. by providing a plurality of mounting locations on the wind tunnel cover 15 side, further convenience can be obtained. Can be improved. Further, in the present embodiment, the wind tunnel cover 15 is configured separately from the main body housing 2, but the main body housing 2 itself may have a configuration in which an inclined surface is provided so as to narrow down toward the lower end, The improvement of the grass collection rate similar to the above-mentioned embodiment can be expected.

As mentioned above, although demonstrated based on embodiment which shows this invention, this invention is not limited to the above-mentioned form, A various change is possible within the range which does not deviate from the meaning. For example, in the present application, a hand-driven electric lawn mower has been described. However, an internal combustion engine may be used, and a self-propelled type can be similarly applied.

It is a longitudinal cross-sectional view of the lawn mower of the present invention. It is a cross-sectional view of the lawn mower of the present invention. It is an external view of the fan for grass collection for the lawn mower of the present invention. It is an external view of the other shape of the grass-collecting fan for lawn mowers according to the present invention. It is an external view of the other shape of the grass-collecting fan for lawn mowers according to the present invention. It is an external view of the other shape of the grass-collecting fan for lawn mowers according to the present invention. It is an external view of the wind tunnel cover of this invention. It is sectional drawing of the wind tunnel cover of this invention. It is a longitudinal cross-sectional view of the conventional lawn mower. It is an external view of the fan for grass collection for the conventional lawn mower. It is a figure for demonstrating the lawn mower by the prior art, and its usage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lawn mower 2 Housing 2a Discharge port 2b Upper plate 2c Motor case 3 Motor 3a Motor shaft 4 Grass collecting fan 4a Blade 4b Projection 4c Passage 4d Curved surface 5 Wind tunnel 5a Wind tunnel outer wall 6 Disc 7 Cutter 9 Bottom plate 10a Air flow upward 10b Air flow to the horizontal outer side 10c Air flow to the upper side 11 Handle 12a Front wheel 12b Rear wheel 13 Grass collection bag 14 Base 15 Wind tunnel cover 15a Mounting surface 15b Inclined portion 15c Mounting hole

Claims (6)

A main body having a discharge part to which a bag for collecting grass can be connected; a driving source housed in the main body; a rotary blade rotating in conjunction with rotation of the driving source; a fan for collecting grass; It is located between the fan and the discharge part, and has a wind tunnel through which the fan wind passes,
The rotating blade has a larger rotating outer diameter than the grass collecting fan,
In a lawn mower configured to have a grass collecting fan positioned above the rotary blade,
A lawnmower characterized in that the grass collecting fan is provided with a guide part for blowing a part of the fan wind obliquely upward and a horizontal air passage for blowing a part of the fan wind in the radial direction of the fan. .   The lawn mower according to claim 1, wherein the guide portion includes a protrusion integrally provided on a base of the grass collecting fan.   The guide portion is independently arranged between any one of a plurality of blades arranged substantially radially on the grass collecting fan and a blade adjacent to any one of the blades. The lawn mower according to claim 1 or 2.   The lawn mower according to claim 3, wherein the guide part has an inclined surface that becomes higher radially outward from a rotation center of the rotary blade and the grass collecting fan.   The lawn mower according to any one of claims 1 to 4, wherein an inner diameter of the wind tunnel is larger than a rotation outer diameter of the rotary blade. At least the lower side of the cylindrical outer peripheral wall constituting the wind tunnel on the side opposite to the discharge part as viewed from the fan has an inclined part that inclines in a direction approaching the rotational center of the rotary blade and the grass collecting fan as it goes to the lower end. The lawn mower according to any one of claims 1 to 5, wherein the lawn mower is provided.

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