JPH0775942B2 - Walk-type power tiller with cylinder forward 4 cycle engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a walk-behind power cultivator equipped with a 4-cycle engine having a horizontal or obliquely forward cylinder, and is capable of improving both forward descent tilt performance and steering performance. Provide something that can also protect the spark plug.

<Background of the Invention> In most of conventional walk-type power tillers, a vertical engine is mounted on an engine support frame in an upright state, and a fuel tank is mounted on the vertical engine. The position of the center of gravity of the entire aircraft was high, and the field of view at the lower front was narrow, so the maneuverability was not good.

Therefore, the applicant first proposed a walk-behind cultivator as shown in FIG.

That is, according to the preceding proposal, the cylinder 2 is mounted on the engine support frame 100 in a state in which the cylinder 2 is projected obliquely forward from the crankcase 1 of the 4-cycle engine E.
The rear part 3 is fixed to the main transmission case 4, and the crankcase 1
The fuel tank 101 and the muffler 102 are arranged in the dead space above the cylinder 2 so as to lower the center of gravity of the walk-type cultivator and to widen the field of view in the lower front. .

Moreover, in the above-mentioned prior proposal, by orienting the cylinder 2 of the engine E upward and upward on the engine support frame 100, the engine E generated when the cylinder 2 is oriented upward and rearward and the main transmission arranged behind it. The dead space between the case 4 and the case 4 is eliminated, and the length in the front-rear direction of the walk-type cultivator can be made compact.

However, in the above-mentioned prior proposal, the engine E is disposed above by the height of the engine support frame 100, the upper and lower bulkiness of the cultivator is not eliminated, and the structure becomes complicated.

<Prior Art> On the other hand, in Japanese Utility Model Publication No. 36-913 (see FIG. 4), a cylinder 2 is horizontally projected from a crankcase 1 of an engine E, and a rear portion 3 of the crankcase 1 is mainly used. A walk-type power cultivator in which the engine support frame 100 is omitted by directly fixing it to the upper half front part 5 of the transmission case 4 is disclosed.

This walk-type power cultivator has an advantage that the bulkiness can be suppressed as much as the engine support frame 100 can be omitted.

<Problems to be Solved by the Invention> However, the above conventional techniques have the following problems.

(1) Since the cylinder 2 is horizontal, the upper and lower distances between the cylinder 2 and the stored oil surface of the oil pan provided below the engine E are very close to each other. If the oil is stored in the oil pan, the oil stored in the oil pan is likely to easily enter the cylinder 2 when the vehicle is tilted forward and downward, and the tilting performance of the cultivator is low.

(2) If an engine protection frame is attached to the intermediate height part of the cultivator, the engine E having an oil pan at the bottom and the fuel tank 101 and the like are moved upward in sequence by the height of the protection frame. As a result, the front part of the cultivator becomes bulky, the center of gravity of the cultivator as a whole is raised, and the field of view in the lower front is narrowed, resulting in poor maneuverability.

(3) Since the cylinder 2 is projected horizontally forward, in the gasoline engine E, there is a great possibility that the spark plug may be projected at the leading edge and may be unexpectedly damaged by an external force when the cultivator is used.

An object of the present invention is to improve both the tilting performance and the steering performance of a walk-behind power cultivator and to protect the ignition plug as well.

<Means for Solving Problems> Means for achieving the above problems will be described below with reference to the drawings corresponding to the embodiments.

That is, the present invention is directed to the cylinder front facing 4 described in the prior art.
While further improving the walking type power cultivator with a cycle engine, run the engine protection frame 7 back and forth on both left and right lateral parts of the lower side of the crankcase 1, and fix the rear part 8 of the protection frame to the main transmission case 4. , The front portion 14 of the protective frame is extended to the front side of the cylinder head 10 and the spark plug 11, and the oil pan 6 is projected downward from the lower part of the crankcase 1 so that the inter-frame space 12 between the left and right engine protective frames 7 is provided. It is characterized by being submerged in.

<Operation> The oil pan 6 is projected and sunk into the inter-frame space 12 between the left and right engine protection frames 7, so that the oil storage surface of the oil pan 6 with respect to the cylinder 2 can be sufficiently lowered, and the cultivator can be operated. Even when the vehicle is tilted downward at a large angle, it is possible to effectively prevent the stored oil from remaining in the oil pan 6 and entering the cylinder 2.

Further, the oil pan 6 is sunk into the inter-frame space 12 between the left and right engine protection frames 7 to lower the engine E and lower the overall center of gravity of the walk-behind power cultivator T. The operator can have a sufficiently wide field of view in the front down direction as seen by the operator.

<Effects of the Invention> (1) Even if the cultivator is tilted forward at a large angle and used, oil can be effectively prevented from entering the cylinder, so that the walk-type power cultivator can be sufficiently tilted forward. Can be improved.

(2) Since the center of gravity of the walking type power cultivator as a whole can be lowered and the field of view in the front down direction can be sufficiently widened, the operability of the cultivator can be improved.

(3) Since the front part of the protective frame extends to the front side of the cylinder head and the spark plug, the spark plug can be reliably protected and unexpected damage due to external force can be eliminated.

<Example> Hereinafter, an example of the present invention is described based on a drawing.

Fig. 1 is a right side cutaway view of a main part of a walk-behind power cultivator equipped with a cylinder forward 4-cycle gasoline engine, and Fig. 2 is a schematic front view of the walk-behind power cultivator. The built-in main transmission case 4 is interlockingly connected in the front-rear direction, a handle 15 is attached upward from the main transmission case 4, and a rotor 17 is attached to an axle 16 below the handle 15.

The cylinder block 18 is integrally extended from the crankcase 1 of the engine E in a diagonally forward direction, the cylinder head 10 is fixed to the cylinder block 18, and the cylinder 2 is opened in a diagonally forward direction at the center of the cylinder block 18 and is attached to the crankshaft 19. The interlocking piston 20 is slidably vertically slidably fitted into the cylinder 2.

The rear part 3 of the crankcase 1 is formed on a vertical fixed surface, and the case rear part 3 is formed on the upper half front surface 5 of the main transmission case 4.
Is fixed and the engine E is integrated with the main transmission case 4.

Further, an oil pan 6 is deeply extended and fixed downward from the lower portion of the crankcase 1, and a front portion thereof is projected to a portion 21 reaching a midway portion of the cylinder 2, and a rear portion thereof is flush with a rear portion 3 of the crankcase 1. It extends to the part 22 where it becomes uniform.

The spark plug 11 is inserted upward from the lower front part of the cylinder head 10 so as to face the combustion chamber provided on the lower surface of the head 10, and the intake / exhaust port is opened in the cylinder head 10 for intake / exhaust. Let the valve face these.

The fuel tank 23 is arranged in the space above the crankcase 1 to the cylinder block 18, and the engine E
This is mounted and fixed to the support rod 24 that has been launched from.

On the other hand, outside the left and right sides of the oil pan 6, a substantially U-shaped engine protection frame 7 is run forward and backward on both left and right sides of the lower side of the crankcase 1, and front and rear base end portions 8 thereof are provided. Is fixed to the front surface of the main transmission case 4 near the lower side.

The front portion 14 of the engine protection frame 7 is folded upward and extended to the front upper space 25 of the cylinder head 10. Particularly, the most distal end portion 7a thereof is as shown in FIG. 1 and FIG. The cylinder block 18 is configured so as to be vertically raised and reach above the position of the spark plug 11.
The lower surface of the cylinder head 10, the lower surface of the cylinder head 10, and the front surface near the lower part.
The spark plug 11 is effectively protected from external force by the engine protection frame 7.

The oil pan 6 is formed by sinking into the inter-frame space 12 between the engine protection frames 7 passing through the left and right sides thereof, and the oil surface of the oil stored in the oil pan 6 is a cylinder. Walk-type power cultivator T with a large distance from 2.
The front descent performance of is increased.

As described above, according to the present invention, the rear portion of the crankcase 1 of the 4-cycle engine is directly fixed to the main transmission case 4,
Since the oil pan 6 is formed by sinking from below the crankcase 1 into the inter-frame space 12 between the engine support frames 7 running on the left and right side surfaces, the oil pan 6
The bottom surface of the above is acceptable as long as it is below the plane including the engine support frame 7, but it is better to sink the oil pan 7 deeply in order to improve the tilt performance.

Further, the 4-cycle engine E is not limited to the gasoline engine, but may be a diesel engine or the like.
Main transmission case 4, which is linked with, does not matter whether the mission is on or off.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a right side cutaway view of a main part of a walk-behind power tiller equipped with a cylinder forward 4-cycle gasoline engine, and FIG. 2 is a schematic front view thereof.
FIG. 3 is a diagram corresponding to FIG. 1 showing a prior proposal, and FIG. 4 is a diagram corresponding to FIG. 1 showing a conventional technique. 1 ... Crank case, 2 ... Cylinder, 3 ... 1 rear part, 4 ... Main transmission case, 5 ... 4 upper half front part, 6 ...
Oil pan, 7 ... Engine support frame, 8 ... 7 rear part,
10 …… Cylinder head, 11 …… Spark plug, 12 …… 7 space between frames, 14 …… 7 front part, E …… 4 cycle engine.

Claims (1)

[Claims] 1. A crankcase 1 for a four-cycle engine E.
The rear part 3 of the crankcase 1 is a walk-type power cultivator T with the cylinder 2 protruding horizontally or obliquely forward.
In a walk-behind power cultivator with a cylinder forward 4-cycle engine, which is fixed to the upper half front part 5 of the main transmission case 4, the engine protection frame 7 is run back and forth on both left and right lateral parts below the crankcase 1. The rear portion 8 of the protective frame is fixed to the main transmission case 4, the front portion 14 of the protective frame extends to the front side of the cylinder head 10 and the spark plug 11, and the oil pan 6 projects downward from the lower portion of the crankcase 1. A walk-type power tiller with a cylinder forward-looking 4-cycle engine, characterized in that it is sunk into the inter-frame space 12 between the left and right engine protection frames 7.