JPH02233826A - Vertical crankshaft engine for lawn mower - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Industrial Application Field> The present invention relates to a vertical crankshaft engine mounted on a lawn mower.

<Conventional technology> Conventionally, in lawn mowers, a cutter blade that can rotate horizontally is received in a power/Sotano 1 housing that also serves as a frame, and the cutter blade is driven by an engine mounted on the top of the Cutano 1 housing. The grass was cut by cutting the grass, and the cut grass was then discharged outside (for example, in 1983,
(Refer to Publication No.-188430). The engines of such lawn mowers are vertical crankshaft engines in which the crankshaft is arranged vertically and a recoil switch, cooling fan, and flywheel are installed above the crankshaft. The above-mentioned power and sota blades are arranged in the area.

In addition, in order to improve the performance of the above engine, the conventional OHI
! Instead of an engine, there is a tendency to adopt an OHC type engine having a transmission device in which a camshaft is disposed on the cylinder side and a timing belt is connected between the camshaft and the crankshaft.

<Problems to be Solved by the Invention> However, the mechanical sliding noise generated by the transmission device and the wind noise generated by the cooling fan are relatively large, and it is desirable to reduce the noise as much as possible. For example, if a soundproof structure is separately provided, the cost will increase.

On the other hand, lawn mowers are sometimes used on uneven terrain, so
It is desirable to lower the overall height and center of gravity as much as possible to improve its stability and maneuverability. Since the cutter blade is shaped in the L direction, the cutter blade is spaced apart from the engine to some extent, resulting in a problem that the overall height and center of gravity become higher.

In view of these problems of the prior art, the main object of the present invention is to provide a vertical crankshaft engine for a lawn mower that reduces noise and improves stability and maneuverability.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, the present invention provides a method for driving a cutter blade that can rotate horizontally at the lower end of a vertically arranged crankshaft. The vertical crankshaft engine for a lawn mower includes a timing pulley and a timing boot provided on the camshaft and the crankshaft, respectively, for interlocking connection with the camshaft disposed on the side of the cylinder head of the crankshaft. A transmission device consisting of a timing belt stretched horizontally, a housing chamber for the transmission device defined inside the engine body, and the crankshaft between the engine body and the cutter blade. This is achieved by providing a vertical crankshaft engine for a lawn mower, characterized in that it has an engine cooling fan fixedly attached to the engine.

In this way, the transmission is covered by the cylinder block and the cooling fan is located below the engine, thereby reducing noise. In particular, if the cooling fan is disposed so as to be covered by the cutter housing, noise can be further reduced. In addition, the cooling fan is lowered and the overall height and center of gravity of the lawn mower are lowered, thereby improving stability and maneuverability.

Embodiments Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the entire lawn mower 1.

In the lawn mower 1, a cutter blade 15 (to be described later) is received inside a cutter housing 2 having a flat bowl shape with an open bottom, and an engine 3 for driving the cutter blade 15 is mounted on the top of the cutter housing 2.

The cutter housing 2 also serves as a frame, and has running wheels 4 disposed at the front, rear, left, and right corners, and a handle 5 at the rear.

The engine 3 is fixed on the cutter housing 2, and the top surface of the engine is covered with a cover 6. An injection port 7 having a filler cap is provided on the top surface of the cover 6 to inject gasoline.

As clearly shown in FIG. 2, the engine 3 includes a crankcase 8, a cylinder block 9 extending in the lateral direction of the case (to the left in FIG. 2), and a cylinder head 10.
and a crankshaft 11 whose both ends protrude in the vertical direction. The engine 3 is located at the upper end of the crankshaft 11.
A coil starter 12 is provided for starting the engine. At the lower end of the crankshaft 11, from the engine 3 side, there is a flywheel 13 and a cooling fan 14 consisting of a centrifugal fan.
, cutter blade 15 are provided in this order. Note that the cooling fan 14 and cutter blade 15 are received inside the cutter housing 2.

On the other hand, a camshaft 16 is disposed within the cylinder head 10. Further, a cavity 17 is defined in the lower part of the engine 3, and timing pulleys 19 and 20 provided at the lower part of the crankshaft 11 and the camshaft 16, respectively, are installed in the cavity.
A transmission device Rl8 consisting of a timing belt 21 wound between these two pulleys is received.

Note that a passage 22 is formed on the outer periphery of the cooling fan 14 inside the cutter housing 2 .

This passage 22 communicates with a discharge port 23 formed at the rear of the cutter housing 2, and the grass cut by the cutter blade 15 is discharged to the outside through the passage 22.

In conventional engines, the transmission device is installed outside the engine, and the cooling fan is installed above the engine, so the mechanical sliding noise generated by the transmission device and the cooling Noise caused by wind noise from the fan is a problem, but according to this embodiment, the transmission device 18 is received inside the engine 3, and the cooling fan 14 is covered by the cutter housing 2 at the bottom of the engine 3. Therefore, noise is reduced without the need for a separate soundproofing structure. In addition, in conventional lawn mower vertical crankshaft engines, the flywheel and cooling fan are
Because it is fixed to the crankshaft on the F side, the overall height and center of gravity of the lawnmower tends to be relatively high, but in this implementation -
According to No. 1, a flywheel 13 and a cooling fan 14 are arranged below the engine 3, and in particular, the cooling fan 14 is
Since it is received in the gap created between the engine 3 and the cutter blade 15 to form a passage 22 for discharging cut grass to the outside, the overall height and center of gravity of the lawn mower 1 are relatively low. ing.

The engine 3 of such a lawnmower 1 is connected to the recoil starter 1.
2, the flywheel 13, cooling fan 14, and cutter blade 15 rotate with the rotation of the crankshaft 11, mowing the lawn appropriately, and cutting the grass through the passage 22 and the υF outlet 23.
The cut grass is discharged to the outside through the At that time, the second
As shown by the arrow in the figure, the cooling air of the engine 3 flows from the main body side to the lower side of the cutter housing 2.

[Effects of the Invention] As described above, according to the present invention, the transmission device is received in the engine, and the engine cooling fan is disposed below the engine between the engine and the cutter blade, thereby reducing noise. It also lowers the overall height and center of gravity, improving stability and maneuverability. Incidentally, if the cooling fan is disposed so as to be covered by the cutter housing, the noise can be further reduced. From the above, the effects of the present invention are significant.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the construction of a lawn mower to which the present invention is applied. FIG. 2 is a schematic cross-sectional view showing only the main parts of FIG. 1. 1...Lawn mowing vA 2...Cutter housing 3...Engine 4...Wheel 5...Handle 6...Cover 7...Inlet 8
... Crank case 9 ... Cylinder block 10.
...Cylinder head 11...Crankshaft 12...
・Recoil starter 13...flywheel 14...
・Cooling fan 15...Cutter blade 16...Camshaft 17...Empty chamber 18...Transmission device 19,
20...Timing pulley 21...Timing belt

Claims (1)

[Scope of Claims] A vertical crankshaft engine for a lawn mower for driving a cutter blade that can rotate horizontally at the lower end of a vertically arranged crankshaft, the engine being disposed on the side of the cylinder head of the crankshaft. a transmission device comprising a timing pulley provided on the camshaft and the crankshaft, respectively, and a timing belt horizontally stretched around the timing pulley for interlocking connection with the camshaft; and the engine body. A vertical crank for a lawn mower, comprising: a housing chamber for the transmission device defined therein; and an engine cooling fan fixed to the crankshaft between the engine body and the cutter blade. shaft engine.