JPH07112383B2 - Lawn mower - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lawnmower equipped with a vertical internal combustion engine having a vertical crankshaft.

(Prior Art) Some lawnmowers use an internal combustion engine as a power source to rotationally drive a cutter blade.

As such a lawn mower, for example, as described in JP-A-59-179010, an internal combustion engine is mounted on a machine body having wheels arranged at four corners and operated by a handle provided at the rear of the machine body. Has become. The internal combustion engine as the power source operates the push rod by the rotation of the cam shaft, and the OHV that opens and closes the intake and exhaust valves via the rocker arm.
Using a valve mechanism that provides an appropriate output with a relatively simple structure, a cutter blade is attached to a vertical crankshaft, and lawn mowing is performed while rotating the blade in a horizontal plane.

(Problem of the Invention) In a lawnmower, the intake system, the exhaust system, and the fuel tank are arranged around the cylinder portion in a well-balanced manner to improve the operability of the lawn mower and reduce the protrusion of the internal combustion engine. However, the challenge is to make it compact and to prevent grass and grass from getting entangled.

(Means for Solving the Problems) In order to solve the above problems, the present invention is an internal combustion engine in which a push rod is actuated by rotation of a camshaft that interlocks with a crankshaft, and an intake / exhaust valve is opened / closed via a rocker arm. Is mounted with the cylinder part horizontal and the crankshaft vertical, and a weeding part that projects backward and opens at the upper part of the housing that covers the cutter blade rotatably mounted on the crankshaft in a horizontal plane. In the lawn mower provided with, a muffler is connected to the outside of the one side of the cylinder part via an exhaust pipe, a carburetor is arranged on the side surface of the other side of the cylinder part, and the carburetor is connected via a bent intake conduit. Connected to the crankcase is arranged above the carburetor, the fuel tank is attached to the crankcase via a stay, the muffler and the air cleaner are connected. And the fuel tank is disposed within a range between the height of the weeding portion and the height of the top cover that covers the crankcase, and the muffler and the air cleaner are substantially equidistant on the left and right sides of a vertical surface of the cylinder axis. The fuel tank is disposed inside, and is located at a position approximately between two positions, a position symmetrical to the air cleaner and a position symmetrical to the muffler with respect to the crankshaft in a top view.

(Operation) According to the present invention, the push rod is actuated by the rotation of the cam shaft that interlocks with the crank shaft, the intake and exhaust valves are opened and closed via the rocker arm, and the cutter blade attached to the vertical crank shaft rotates in the horizontal plane. . Exhaust gas from the internal combustion engine is discharged from a muffler connected to the outside of one side of the cylinder part through an exhaust pipe, and a carburetor disposed on the side surface of the other side of the cylinder part, and a bent intake conduit to the carburetor. Intake air is taken in through an air cleaner connected via the air cleaner.

(Embodiment) Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the figure, reference numeral 1 is a lawn mower, and its body 2 is provided with front wheels 3 and rear wheels 4, and a handle 5 is extended from the rear part of the body 2 to the upper rear side. A housing 6 is provided in the machine body 2, the housing 6 is opened downward, and an internal combustion engine 7 is mounted on the upper portion thereof. The wheels are driven by the power of the internal combustion engine 7 to run, and the crankshaft 8 of the internal combustion engine 7 arranged in the vertical direction extends into the housing 6, and the housing 6 is attached to the lower end of the crankshaft 8.
The cutter blade 9 arranged inside the
The cutter blade 9 is rotatable on a horizontal plane.

On one side of the internal combustion engine 7, as shown in FIG. 2, an upper part of the housing 6 is provided with a weeding portion 10 which gradually projects upward from the front side to the rear side, and the weeding portion 10 has a discharge port 10a.
A grass storage bag 11 is attached to the handle 5 at the rear of the grass storage bag 11. The grass intake 11a provided on the upper surface of the grass storage bag 11 faces the discharge outlet 10a of the grass discharge portion 10.

As shown in FIG. 2 to FIG. 4, the internal combustion engine 7 has its crankcase 12 arranged vertically and its skirt portion 13 fixed to the upper part of the housing 6, from the crankcase 12 to the cylinder block 14 and cylinder head 15. The cylinder portion 16 is horizontally arranged rearward. This internal combustion engine 7
4, an OHV valve mechanism is used, the gear 18 of the cam shaft 17 arranged parallel to the crank shaft 8 meshes with the gear 19 of the crank shaft 8, and the cam portion 20 of the cam shaft 17 is It is in contact with the tappet 21a of the push rod 21. The push rod 21 is arranged in the cylinder axial direction, and the other end is engaged with a rocker arm 22 supported by the cylinder head 15, and the rocker arm 22 operates to open and close the exhaust valve 23. The intake valve 24 is similarly configured, and the exhaust valve 23 and the intake valve 24 are opened / closed at a predetermined timing.

As clearly shown in FIGS. 1 and 3, the cylinder head 15
An exhaust system 27 including an exhaust pipe 25 and a muffler 26 on the side of the weeding section 10 (one side), and an intake pipe 28 and a carburetor 29 on the other side.
Further, an intake system 31 including an air cleaner 30 and the like is arranged, and a point-down plug 32 is attached to the side opposite to the grass weed portion 10 so as to face outward and upward.

That is, the exhaust pipe 25 that constitutes the exhaust system 27 is the cylinder head.
A muffler 26 is connected to the exhaust pipe 25 by extending from the upper side of 15 toward the outer upper side of the one side (the weeding section 10 side). The muffler 26 is higher than the height H1 of the weeding section 10 and is located above the weeding section 10, and the height H2 of the muffler 26 is slightly higher than the cylinder head 15. The intake pipe 28 forming the intake system 31 extends from the lower portion of the cylinder head 15 toward the other side, and the carburetor 29 connected to the intake pipe 28 is provided on the side surface of the other side of the cylinder head 15. It is placed in close proximity. An air cleaner 30 connected to the carburetor 29 via a bent intake conduit is arranged above the carburetor 29,
The height of the muffler 26 and the air cleaner 30 is the height H1 of the weeding part 10.
And the height H3 of the top cover 34 that covers the upper portion of the crankcase 12 of the internal combustion engine 7. Further, the air cleaner 30 and the muffler 26 are arranged within the range of substantially equal distances D1 and D2 on the vertical plane L of the cylinder axis. The fuel tank 35 is arranged on the front side of the fuselage 2 and is attached to the crankcase 12 via a stay 36 so that the crankcase
Located above twelve. The fuel tank 26 is in the range between the height H1 of the weeding part 10 and the height H3 of the top cover 34,
The fuel tank 35 is arranged at a position approximately symmetrical between two positions, a position symmetrical with the air cleaner 30 and a position symmetrical with the muffler 26 with respect to the crankshaft 8 in a top view.

Therefore, when the lawnmower 1 is used for lawn mowing, the internal combustion engine 7 is started and the handle 5 is held for traveling. Then, while traveling, the cutter blade 9 rotates to mow the lawn, and the mowed lawn is discharged from the weeding section 10 at the outlet 10a and the lawn inlet 11a.
Through the grass storage bag 11.

When changing the direction of this lawnmower 1, handle 5
When is pressed downward, the front wheel 3 side floats around the rear wheel 4 as a fulcrum, and the handle 5 is rotated left and right as it is. At this time, since the cylinder portion 16 of the internal combustion engine 7 is arranged rearward, the center of gravity of the machine body 2 is close to the rear wheel 4, so that the front wheel 3 can be floated with a light force and the direction can be easily changed. .

The intake system including the intake pipe 28, the carburetor 29, the air cleaner 31 and the like, and the exhaust system 27 including the exhaust pipe 25 and the muffler 26 are suppressed within the height H3 of the internal combustion engine (top cover 34). And the exhaust system 27 are arranged at substantially equal distances D1 and D2 to the left and right with respect to the vertical plane L of the cylinder axis, and the fuel tank 35 is within the height range of the top cover 34. Air cleaner for crankshaft 8 in top view
Since it is arranged at a position approximately between the position symmetrical with 30 and the position symmetrical with the muffler 26, the balance is good, and the projecting portion is reduced to be compact and the running stability is improved. And the operability is improved.

Muffler 26, air cleaner 30 and fuel tank 35
Since the carburetor 29 and the cylinder portion 16 are disposed above the height H1 of the hood 10 and substantially above the carburetor 29 and the cylinder portion 16, the periphery of the carburetor 29 and the cylinder portion 16 is exposed. The carburetor 29 and the cylinder portion 16 can be maintained even if the distance between them is narrow. And the vaporizer 29,
Since the space between the cylinder portion 16 and the housing 6 may be narrow, the upper wall of the housing 6 can be raised to make the housing 6 deeper by that amount, and then the grass cut by the cutter blade 9 can be stored in the housing 6. No more clogging with.

In addition, since it is compact and has a reduced number of protrusions, cut grass, grass, etc. do not get tangled. Further, by disposing the ignition plug 32 on the side opposite to the grass weeding section 10, a work space is secured around the ignition plug 32, and the operation of attaching and detaching the ignition plug 32 with a plug wrench is easy, and the internal combustion engine 7
There is no danger of the hand touching the overheated muffler 26 even immediately after the stop, and the maintainability is improved.

(Effect of the Invention) In the present invention, the muffler is connected to the upper outside of one side of the cylinder part through the exhaust pipe, the carburetor is arranged on the side surface of the other side of the cylinder part, and the bent intake conduit is connected to the carburetor. An air cleaner connected via is placed above the carburetor,
The fuel tank is attached to the crankcase via a stay, the muffler, the air cleaner and the fuel tank are arranged within the range between the height of the weeding part and the height of the top cover covering the crankcase, and the muffler and the air cleaner are cylinders. The fuel tanks are arranged within a range of approximately equal distances on the left and right of the vertical plane of the axis, and the fuel tank is arranged in a position between the two positions, which are symmetrical to the air cleaner and symmetrical to the muffler with respect to the clan axis in a top view. Has been done. Therefore, the lawn mower is well-balanced, the projecting portion is reduced, and the lawn mower is compact, which improves running stability and operability.

Further, since the muffler, the air cleaner and the fuel tank are arranged in the range between the height of the weeding portion and the height of the top cover, the carburetor and the periphery of the cylinder portion are exposed,
The carburetor and the cylinder can be maintained even if the distance between the carburetor and the cylinder is small. And since the distance between the carburetor and the cylinder part and the housing may be narrow, it is possible to raise the upper wall of the housing to make the housing deeper by that amount, and then the grass cut by the cutter blade will be stored in the housing. No more clogging.

Moreover, there is no protruding portion around the internal combustion engine 7 and the outer shape is compact, and the cut grass and grass are not entangled and the operability is excellent.

[Brief description of drawings]

1 is a plan view of the lawn mower of the present invention, FIG. 2 is a side view of the lawn mower, FIG. 3 is a III-III sectional view of FIG. 1, and FIG. 4 is a IV-IV sectional view of FIG. Is. In the figure, reference numeral 1 is a lawn mower, 2 is a body, 6 is a housing, 7 is an internal combustion engine, 8 is a crankshaft, 9 is a cutter blade, and 10 is a blade.
Is a weeding part, 12 is a crankcase, 16 is a cylinder part, 25 is an exhaust pipe, 26 is a muffler, 29 is a carburetor, 30 is an air cleaner,
34 is a top cover, 35 is a fuel tank, and 36 is a stay.

Claims (1)

[Claims] Claim: What is claimed is: 1. An internal combustion engine in which a push rod is operated by the rotation of a cam shaft which interlocks with a crank shaft to open and close an intake / exhaust valve via a rocker arm, with its cylinder part being horizontal and the crank shaft being vertical. In the lawn mower provided with a weeding portion projecting rearward and opening at the upper part of the housing that covers the cutter blade rotatably attached to the crankshaft in a horizontal plane, the outside of one side of the cylinder portion above A muffler is connected via an exhaust pipe, a carburetor is arranged on the other side surface of the cylinder portion, an air cleaner connected to the carburetor via a bent intake conduit is arranged above the carburetor, and a fuel tank is installed. Is attached to the crankcase via a stay, and the muffler,
The air cleaner and the fuel tank are arranged within a range between the height of the weeding portion and the height of the top cover that covers the crankcase, and the muffler and the air cleaner are substantially equidistant from each other on the right and left of a vertical plane of the cylinder axis. And the fuel tank is arranged at a position substantially in between two positions, which are symmetrical with respect to the crankshaft with respect to the air cleaner and symmetrical with the muffler with respect to the crankshaft in a top view. And lawn mower.