JPH0799093B2 - Vertical engine for lawn mower - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a vertical engine for a lawn mower in which a crankshaft is vertically arranged.

(Prior Art) This type of vertical mower vertical engine is mounted on the cutter housing of a lawn mower so that its crankshaft is vertical and the cylinder is horizontal. In the case of a scroll having a gradually increasing height, the carburetor was arranged on the side of the lower scroll in order to lower the set position of the fuel tank and improve the stability of the fuselage.

On the other hand, in this type of lawn mower vertical engine,
A cooling fan is attached to the upper end of the vertically arranged crankshaft, and cooling air generated by the cooling fan is guided downward to forcibly cool the cylinder and the cylinder head. 59-70838, 61-534
22).

(Problems to be Solved by the Invention) However, in the conventional vertical engine for a lawn mower, the cooling air having a high temperature by cooling the cylinder and the cylinder head has a low resistance side of the scroll having a small resistance. Since it is easy to be discharged to, the carburetor arranged on the lower side of this scroll is heated by the cooling air,
There arise problems that the air-fuel ratio fluctuates due to temperature changes and, in the extreme case, barcolation occurs to impair the operational stability of the engine.

The present invention has been made in view of the above-mentioned conventional problems, and the object thereof is to prevent heat damage due to cooling air to the carburetor and ensure high operation stability, and stability of the airframe. It is to provide a vertical engine for a lawn mower that does not damage the engine.

(Means for Solving the Problems) In order to achieve the above object, the present invention is designed so that the crankshaft is vertical and the cylinder is horizontal on a cutter housing having a scroll whose height gradually increases toward the weeding mouth. In a vertical engine for a lawn mower, which is mounted and has a carburetor and a muffler arranged on the side of a cylinder, the carburetor is arranged on the side of the cutter housing where the scroll height is high and above the carburetor. A fuel tank is arranged.

(Operation) As a result, the cooling air, which has increased in temperature by cooling the cylinder and cylinder head of the vertical engine, flows toward the side of the scroll having a low resistance and having a low height. The carburetor arranged on the higher side is not thermally affected by the cooling air, and the operational stability of the vertical engine for the lawn mower is ensured. or,
As a result of preventing the heat damage to the carburetor in this way, the fuel tank can be installed at the same height position as the conventional one, even though the carburetor is arranged on the higher side of the scroll. There is no loss of stability.

(Embodiment) An embodiment of the present invention will be described below with reference to the accompanying drawings.

First, the overall structure of the lawn mower will be described with reference to the perspective view of FIG. 6 and the plan view of FIG. 7. In the figure, 1 is a cutter housing, and the front part thereof is the front left and right wheels 2,2. Is supported by the rear wheels 3, 3, which are the rear drive wheels.
A vertical engine 10 according to the present invention is mounted on the cutter housing 1. A bag-shaped catcher 4 for storing cut grass is detachably attached to the rear wheel of the cutter housing 1, and an operation handle 5 extends obliquely rearward and upward from the rear of the cutter housing 1. The operation wheel 5 has a rear wheel portion provided with an operation portion 6 for the operator to perform a cutting operation and a traveling operation.

Here, details of the vertical engine 10 will be described with reference to FIGS. 1 to 5. 1 is a front view of the lawn mower (a view in the direction of arrow A in FIG. 7), and FIG. 2 is a vertical side view of the vertical engine section for the lawn mower (cross section taken along the line II-II in FIG. 7). 3), FIG. 3 is a sectional view taken along the line III-III in FIG. 2, FIG. 4 is a view in the direction of arrow B in FIG. 2 with the cylinder head cover removed, and FIG. 5 is V- in FIG. It is a V line sectional view.

As shown in FIGS. 2 and 3, the vertical engine 10 is mounted on the cutter housing 1 so that its cylinder 11 is horizontal and the crankshaft 12 is vertical. A flywheel 13 and a cooling fan 14 which are integrated with each other are connected to an upper end portion by a nut 15, and the flywheel 13 and the cooling fan 14 are covered with an air guide cover 16. In FIG. 2, reference numeral 17 is a recoy starter, 18 is a fuel tank, 19 is a cap, and the cap 19 has a plurality of suction holes 19a.

At the lower end of the crankshaft 12, as shown in FIG.
21 and a cutting blade 22 are bound by bolts 23, 23, and the weeding fan 21 and the cutting blade 22 are housed in the cutter housing 1. Both ends of the cutting blade 22 have cutting edges 22a, 22
a (only one shown).

On the other hand, a piston 24 is slidably fitted in the housing 11, and the piston 24 is connected to the crankshaft 12 via a connecting rod 25. A cylinder head 26 is attached to the end of the cylinder 11, and the cylinder head 26 is covered with a cylinder head cover 27.
As shown in FIGS. 2 and 5, an exhaust port 28 is opened upward and an intake port 29 is opened downward on the end face of the cylinder head 26 facing the inside of the cylinder 11. The intake port 29 is opened and closed by an exhaust valve 30 and an intake valve 31, which are slidably inserted in the cylinder head 26. The exhaust valve 30 and the intake valve 31 are springs 32, 33.
Is urged to close. The exhaust valve 30 and the intake valve 31 have rocker arms 3 whose tops are swingable.
Each rocker arm 34,3 is in contact with one end of 4,35.
The other end of 5 is inserted into the cylinder 11 and the cylinder head 26 slidably, and the push rod rods 36 and 37 (see FIGS.
(See the drawing), abutting on each end. The other end of the push rod 36 is connected to the crankcase 38 as shown in FIG.
A cam 39 rotatably arranged therein is abuttingly engaged, and the other end of the other push rod 37 is also abuttingly engaged with a cam (not shown) although not shown. As shown in FIG. 3, a screw gear 40 and a timing gear 41 are coaxially connected to a cam shaft (not shown) on which the cam 39 is provided, and the screw gear 40 has a shaft 42 end portion. Is engaged with a screw gear 43, and the shaft 42 extends rearward (rightward in FIG. 3) and is coupled to a drive mechanism (not shown) for the rear wheels 3, 3. . Further, the gear 41 meshes with a gear 44 connected to the intermediate portion of the crankshaft 12.

Further, as shown in FIG. 5, the cylinder head 26 has
An exhaust passage 45 continuous with the exhaust port 28 is formed with an upward slope toward the right in FIG. 5, and an intake passage 46 continuous with the intake port 29 is upward with a slope toward the left in FIG. The exhaust passage 45 is formed above the intake passage 46. In the figure, 47 is a spark plug.

By the way, there is a first
As shown in FIGS. 2 and 3, a scroll 1a having a height gradually increasing toward a weeding opening (not shown) opening in the catcher 4 is formed, and the height of the scroll 1a is as shown in FIG. In, the left side is higher than the right side. An intake passage 46 formed in the cylinder head 26 is opened on the side of the scroll 1a having a higher height (left side in FIG. 1), and the carburetor arranged on the same side in the intake passage 46.
48 is connected, and an air cleaner 49 is further connected to this carburetor 48. The fuel tank 18 is installed above the carburetor 48 and at substantially the same height as the conventional one.

On the other hand, a muffler 50 is arranged on the opposite side of the carburetor 48 with respect to the cylinder 11, that is, on the side where the height of the scroll 1a is low (right side in FIG. 1), and the muffler 50 and the exhaust passage 45 are arranged. And are connected by an exhaust pipe 51. In addition, muffler 50
Is covered by protector 52.

Next, the operation of the vertical engine 10 will be described.

When the crankshaft 12 is driven to rotate while the vertical engine 10 is operating, the cooling fan 14, the weeding fan 21, and the cutting blade 22 that are respectively coupled to the upper and lower ends of the crankshaft 12 rotate together to cool the crankshaft 12. Fan 14 cap
Atmosphere is sucked from a plurality of suction holes 19a formed in 19 to generate cooling air, and the cooling air is guided downward as indicated by an arrow in FIG.
Cool 26. The weeding fan 21 induces wind in the cutter casing 1 to raise grass to be mowed, and the raised grass is mowed by the cutting blades 22a and 22a of the cutting blade 22, and the weeding fan 21 cuts the grass. Scroll 1a accompanying swirling flow induced in 1
Is sent to the weed exit side along with and finally stored in the catcher 4.

By the way, the cooling air which has cooled the cylinder 11 and the cylinder head 26 and has risen in temperature changes its direction to the side having a low resistance, that is, the side having a low height of the scroll 1a, as shown by the arrow in FIG. Flow away. However, since the carburetor 48 is arranged on the higher side of the scroll 1a as described above,
Not heated by hot cooling air, therefore
The formation of the air-fuel mixture becomes unstable due to the occurrence of barcolation and the like, and the malfunction such as the deterioration of the operational stability of the vertical engine 10 is effectively eliminated.

Further, as a result of the vaporizer 48 not being damaged by heat from the cooling air as described above, the mounting height of the vaporizer 48 on the cylinder head 26 can be reduced, and as a result, the vaporizer 48 can be mounted as described above. The intake passage 46 to be cooled can be arranged below the exhaust passage 45, and the exhaust passage 45 portion in which high-temperature exhaust gas passes and the periphery thereof is heated is first efficiently cooled by the cooling air. The cooling efficiency of the entire cylinder head 26 and the cylinder 11 can be improved. At the same time, even if the fuel tank 18 is installed at the same height as the conventional one, the fuel tank of the vaporizer 48
The head against 18 is not reduced, and therefore the tilt performance and the safety of the airframe are not impaired. Further, the push rods 36 and 37 are provided on the side opposite to the intake passage 46 (in FIG. 5,
Since it is arranged on the right side), the intake passage 46 does not need to avoid interference with the push rods 36, 37 due to the arrangement, and can be formed with the shortest distance in the cylinder head 26, so that the carburetor 48 and the combustion chamber in the cylinder 11 can be formed. The distance between them is shortened, and the startability of the vertical engine 10 is improved.

In the above embodiment, the vertical engine of the type in which the camshaft is arranged in the crankcase is described, but the present invention is a so-called overhead camshaft (OHC) type in which the camshaft is arranged in the rocker arm chamber in the cylinder head cover. The same can be applied to the vertical engine of.

(Effects of the Invention) As is clear from the above description, according to the present invention, the carburetor is arranged on the side of the cutter housing where the scroll height is high, and the fuel tank is arranged above the carburetor. The equipment is not thermally adversely affected by the high-temperature cooling air that flows to the low-height side of the scroll with low resistance, and it is possible to ensure the operational stability of the vertical engine for the lawn mower without impairing the stability of the aircraft. The effect of being able to be obtained is obtained.

[Brief description of drawings]

1 is a front view of the lawn mower (a view in the direction of arrow A in FIG. 7),
FIG. 2 is a vertical sectional side view of the vertical engine section for the lawn mower (cross-sectional view taken along the line II-II in FIG. 7), and FIG. 3 is a III-I in FIG.
II line sectional view, FIG. 4 is a view in the direction of arrow B in FIG. 2 with the cylinder head cover removed, FIG. 5 is a VV line sectional view in FIG. 2, and FIG. 6 is a perspective view of a lawn mower. FIG. 7 and FIG. 7 are plan views of the lawnmower. 1 …… Cutter housing, 1a …… Scroll, 10 ……
Vertical engine for lawn mower, 11 …… cylinder, 12 ……
Crankshaft, 18 ... Fuel tank, 26 ... Cylinder head, 36, 37 ... Push rod, 45 ... Exhaust passage, 46 ...
… Intake passage, 48 …… carburetor, 50 …… muffler.

Claims (3)

[Claims] 1. A crank housing is mounted vertically on a cutter housing having a scroll whose height gradually increases toward a grass outlet, and a cylinder is horizontal, and a carburetor and a muffler are arranged on the side of the cylinder. A vertical engine for a lawn mower, wherein the carburetor is arranged on the side of the cutter housing where the scroll height is high, and a fuel tank is arranged above the carburetor. . 2. The vertical engine for a lawn mower according to claim 1, wherein the muffler and the intake / exhaust valve push rod are arranged on the opposite side of the carburetor with respect to the cylinder. 3. The vertical engine for a lawn mower according to claim 1 or 2, wherein an exhaust passage formed in the cylinder head is located above an intake passage.