JP2750149B2 - Vertical crankshaft engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Industrial application field> The present invention relates to an improvement of a vertical crankshaft engine.

<Conventional Technology> For example, in a vertical crankshaft type general-purpose engine in which a crankshaft used for a lawnmower or the like is vertically arranged, it is preferable that the engine can be made as small and lightweight as possible.
On the other hand, even in this kind of general-purpose engine, in recent years, there is a strong tendency to increase the output, and achieving a balance between small size, light weight, and high output has been regarded as one of the important issues.

<Problems to be Solved by the Invention> By the way, as a technique for increasing the output, it is possible to raise the rotation speed or improve the intake / exhaust efficiency. −3234
In the case of an OHV engine as disclosed in Japanese Patent Publication No. 3, the promotion of high output tends to be hindered by problems such as restrictions on the arrangement of the intake and exhaust valves and the inertial mass of the push rod. Was.

The present invention has been made in view of such problems, and a main object of the present invention is to provide a vertical crankshaft engine capable of promoting downsizing and weight reduction of an engine and achieving high output. It is in.

According to the present invention, there is provided a vertical crankshaft engine having a crankshaft arranged vertically, an intake port opening to a combustion chamber, The center of the exhaust port and at least a part of the axis of the intake passage connected to the intake port and the axis of the exhaust passage connected to the exhaust port are on the same plane orthogonal to the crankshaft, and the intake passage and the exhaust passage Is achieved by providing a vertical crankshaft engine characterized in that they extend in opposite directions with respect to the cylinder axis.

<Operation> Since the flow lines of the intake air and the exhaust gas are located on the same plane, the inflow of the air-fuel mixture into the combustion chamber and the exhaust of the combustion gas form a complete cross flow, and are relatively smooth without any resistance. It is performed. In addition, since the intake passage and the exhaust passage are located on a common horizontal plane, when the carburetor and the muffler are substantially directly connected to the cylinder head, a configuration that contributes to a reduction in the height of the engine body is specially provided. It can be realized relatively easily without any design.

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

1 and 2 show the entirety of a four-cycle vertical crankshaft type, forced air-cooled, single-cylinder engine configured according to the present invention. The right side opening of the cylinder block 2 which constitutes the engine body 1 is abuttedly connected with a crankcase 3, and a pair of ball bearings 4 a and 4 b provided at a joint between the cylinder block 2 and the crankcase 3. Thus, the crankshaft 5 is supported along the vertical direction. A piston 8 sliding into a cylinder bore 7 provided in the cylinder block 2 is connected to a crankpin 6 formed at a substantially central portion of the crankshaft 5 via a connecting rod 9.

At the joint between the cylinder block 2 and the crankcase 3, a balancer shaft 10 is supported in parallel with the crankshaft 5. The balancer shaft 10 is for canceling the primary vibrating force caused by the eccentricity of the crankpin 6 and is connected to the crankshaft 5 via gear means 11. It is driven to rotate at a constant speed and in the opposite direction.

The cylinder head is located on the left side of the cylinder block 2.
12 are integrally formed. This cylinder head 12
Has a combustion chamber 13 separated at the left end of the cylinder bore 7;
Exhaust port 14 and intake port 15 opening to the combustion chamber 13
In addition, an exhaust passage 16 and an intake passage 17 extending from these ports 14 and 15 in a direction substantially perpendicular to the crankshaft 5, that is, in a horizontal direction, are formed. The centers of the ports 14 and 15 and the axes of the passages 16 and 17 are respectively in a common horizontal plane, and at the same time, the exhaust passage 16 and the intake passage 17 are in opposite directions with respect to the axis of the cylinder bore 7. Has been extended.

A head cover 18 is joined to the left end of the cylinder head portion 12 by abutment. At the joint between the cylinder head 12 and the head cover 18, as shown in FIG.
A pair of upper and lower journal portions 19a and 19b are formed, and the cam portions 20 extending in parallel with the crankshaft 5 are supported by both ends of the journal portions 19a and 19b. The camshaft 20 has a timing belt 22 wound between a large timing pulley 21a integrally formed at the lower end thereof and a small timing pulley 21b fixed to the crankshaft 5, and the crankshaft 5 It is driven at half the speed of rotation. The transmission mechanism including the timing pulleys 21a and 21b and the timing belt 22 is housed below the cylinder bore 7 in a belt storage chamber B integrally formed with the cylinder block 2.

The cylinder head 12 has a valve spring to open and close the exhaust port 14 and the intake port 15, respectively.
Exhaust valve urged in the normally closed direction with 23a and 23b
24 and an intake valve 25 are provided. The axes of the valve stems of these two valves 24 and 25 are in the same plane orthogonal to the crankshaft 4, that is, in the common horizontal plane. At the same time, the valve stem end has a pair of cams formed on the camshaft 20.
Rocker arms pivotally supported by rocker shafts 27a and 27b extending in the head cover 18 parallel to the cam shaft 20 with respect to 26a and 26b
28a and 28b, respectively.
Is driven to open and close at an appropriate timing according to the rotation of.

On the other hand, a silencer 29 is directly connected to the opening of the exhaust passage 16, and a carburetor 30 is directly connected to the opening of the intake passage 17. The carburetor 30 is connected to a governor mechanism 31 driven by the crankshaft 5 via a link mechanism (not shown), and automatically controls the throttle valve opening so as to maintain the set rotation speed. Have been to be.

Further, an air cleaner case 33 containing a filter element 32 made of filter paper is connected to the upstream end of the intake path of the carburetor 30.

On the other hand, a flywheel 34 is provided at the upper end of the crankshaft 5.
Is fixed. A blade 35 acting as a cooling fan is integrally formed on the outer peripheral portion of the axial end face of the flywheel 34. Further, a permanent magnet 36 is fixed to a part of the outer periphery, and cooperates with an ignition device 37 fixed to the cylinder block side to generate a required ignition spark at a predetermined timing. . Further, a recoil starter 38 is connected to the shaft end of the crankshaft 5.

A lubricating oil tank 39 is disposed on the right side of the crankcase 3. The lubricating oil tank 39 is made of a translucent synthetic resin material. Its bottom walls 40a and 40b are formed in two stages, and a boss 41 projecting downward from a shallow bottom 40a is formed in the crankcase 3 to form a through hole. The hole 42 is fitted in a liquid-tight manner. Continuing with the boss portion 41, a ridge 43 is extended along the inner surface of one side wall of the lubricating oil tank 39 until reaching the upper wall. Open opposite
In addition, a passage 45 that opens into the upper space of the lubricating oil tank 39 via a reed valve 44 is provided therein. The passage 45 allows the lubricating oil to flow only from the bottom of the crankcase 3 toward the upper part of the lubricating oil tank 39.

A second passage 46 extending into the deep bottom portion 40b and communicating with the outside of the upper wall of the lubricating oil tank 39 extends from the inner surface of the other side wall of the lubricating oil tank 39. The second passage 46 has a hose port 47 fitted in an opening in an upper wall thereof, and is connected to a lubricating oil supply path 48 provided in the cylinder block 2 via a flexible tube 49. This lubricating oil supply path 48
A one-way valve 50 that allows only the lubricating oil to flow from the lubricating oil tank 39 is interposed at the most upstream end of the lubricating oil tank 39.

The lubricating oil supply passage 48 extends in the upper wall of the cylinder block 2 along the cylinder axis, and via an oil reservoir 51 formed at an intermediate portion thereof, like the cam journal portion 19a located on the upper side. Upper crank bearing 4a
And lubricating oil is supplied.

According to the lubricating oil supply device, the lubricating oil is sucked into the engine from the lubricating oil tank 39 by the negative pressure generated in the crankcase 3 during the ascent stroke of the piston 8, and the positive pressure generated during the descending stroke of the piston 8 The lubricating oil that has flowed down to the inside of the cylinder block 2
Pushed back to 39.

The upper surface of the engine body 1 configured as described above is almost entirely covered with a cover C that also functions as a fan shroud.

As is well known, as a method of increasing the engine output without increasing the displacement, the introduction of the air-fuel mixture into the combustion chamber and the discharge of the combustion gas can be performed without resistance, that is, the intake and exhaust efficiency can be improved. Improvement is extremely effective. Therefore, in the present invention, the centers of the intake and exhaust ports 14 and 15 are located on the same plane, and the intake and exhaust passages 16 and 17 connected thereto are led out in opposite directions with respect to the cylinder axis. Thereby, the continuity of the streamlines of the intake air and the exhaust air is enhanced.

[Effects of the Invention] As described above, according to the present invention, as shown in the above embodiment, in combination with the elimination of the push rod from the valve train,
The engine speed can be promoted at a higher level. Therefore, high output can be achieved without increasing the size of the engine, and a great effect can be achieved in improving the engine performance. In addition, since the opening positions of the intake and exhaust passages to the outer surface of the cylinder head can be located on the same horizontal plane, the height of the engine body is reduced when the carburetor and the muffler are substantially directly connected to the cylinder head. It can be reduced relatively easily. Therefore, there is a great effect in promoting the downsizing of the engine.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an engine constructed in accordance with the present invention, and FIG.
FIG. 3 is a partial left side view showing the head cover removed. DESCRIPTION OF SYMBOLS 1 ... Engine body, 2 ... Cylinder block 3 ... Crank case, 4a, 4b ... Ball bearing 5 ... Crank shaft, 6 ... Crank pin 7 ... Cylinder bore, 8 ... Piston 9 ... Connecting rod, 10 ... Balancer shaft 11 ... Gear means, 12 ... Cylinder head 13 ... Combustion chamber, 14 ... Exhaust port 15 ... Intake port, 16 ... Exhaust passage 17 ... Intake passage, 18 ... Head cover 19a 19b Journal part 20 Camshaft 21a Large timing pulley 21b Small timing pulley 22 Timing belt 23a / 23b Valve spring 24 Exhaust valve 25 Inlet valve 26a / 26b Cam, 27a / 27b ... Cam shaft 28a / 28b ... Rocker arm 29 ... Silencer, 30 ... Vaporizer 31 ... Governor mechanism, 32 ... Filter element 33 ... Air cleaner case 34 ... Flywheel, 35 ... … Blade 36 …… permanent Stone, 37 igniter 38, recoil starter 39, lubricating oil tank, 40a / 40b, bottom wall 41, boss, 42, through hole 43, ridge, 44, reed valve 45 ... passage, 46 ... second passage 47 ... hose port, 48 ... lubricating oil supply passage 49 ... flexible tube 50 ... one-way valve, 51 ... oil reservoir

Claims (1)

(57) [Claims] 1. A vertical crankshaft engine having a crankshaft arranged vertically, comprising: a center of an intake port and an exhaust port opening to a combustion chamber;
At least a part of the axis of the intake passage connected to the intake port and the axis of the exhaust passage connected to the exhaust port are on the same plane orthogonal to the crankshaft, and the intake passage and the exhaust passage sandwich the cylinder axis. A vertical crankshaft engine characterized by extending in opposite directions to each other.