JP2003314237A - Engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable between an eccentric shaft and a control rod to be lubricated by eliminating the necessity of providing a lubricating unit for special purpose eccentric shaft, and to enable the engine to be reduced in size and weight in the engine having the eccentric shaft provided at the eccentric position of a rotary shaft and coupled to the other end of the control rod. <P>SOLUTION: The engine comprises: a breather chamber 80 formed in an engine body 21 above the eccentric shaft 67; and an oil supply hole 86 provided in the chamber 80 to drip the oil separated from a breather gas by gas-liquid separation in the chamber 80 to the shaft 67. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine,
In particular, a connecting rod having one end connected to a piston via a piston pin, and a sub-rod connected to a crankshaft rotatably supported on an engine body via a crankpin and connected to the other end of the connecting rod, A control rod having one end connected to the sub-rod at a position shifted from a connection position of the connecting rod; and a control rod provided at an eccentric position of a rotation shaft rotatably supported by the engine body and connected to the other end of the control rod. And an eccentric shaft. [0002] Conventionally, such an engine is already known, for example, from US Pat. No. 4,517,931 and the like. In this engine, a power reduced from a crankshaft at a reduction ratio of 1/2 is rotated. The transmission to the shaft makes the stroke of the piston variable. In such an engine, when lubricating between the control rod and the eccentric shaft, a lubricating device for the eccentric shaft is generally provided. When a lubricating device is installed, the engine may be increased in size and weight. [0004] The present invention has been made in view of the above circumstances, and it is not necessary to provide a lubricating device dedicated to an eccentric shaft, thereby enabling lubrication between the eccentric shaft and the control rod, and reducing the size and weight of the engine. The purpose is to provide an engine that can be used. In order to achieve the above object, the present invention provides a connecting rod having one end connected to a piston via a piston pin, and a crankshaft rotatably supported on an engine body. A sub-rod connected to the other end of the connecting rod via a crank pin, a control rod connected at one end to the sub-rod at a position shifted from a connecting position of the connecting rod, and rotatable to the engine body. An eccentric shaft provided at an eccentric position of a rotating shaft supported by the control rod and connected to the other end of the control rod, a breather chamber is formed in the engine body above the eccentric shaft, Oil supply hole for dropping oil separated from breather gas by gas-liquid separation in the breather chamber to the eccentric shaft Is provided. According to such a configuration, the oil separated from the breather gas drops in the eccentric shaft in the breather chamber, so that it is not necessary to provide a dedicated lubricating device for the eccentric shaft, and it is possible to lubricate the eccentric shaft and the control rod. Thus, the size and weight of the engine can be reduced. An embodiment of the present invention will be described below with reference to an embodiment of the present invention shown in the accompanying drawings. 1 to 5 show an embodiment of the present invention. FIG. 1 is a front view of the engine, and FIG. 2 is a longitudinal sectional view of the engine seen from the same direction as FIG. 3 is a sectional view taken along line 3-3 of FIG. 2, FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 2, and FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG. It is. 1 to 3, the engine is an air-cooled single-cylinder engine used for, for example, a working machine.
And a cylinder block 23 projecting obliquely upward from one side surface of the crankcase 22, and a cylinder head 24 joined to the head of the cylinder block 23. A large number of cooling fins 23 are provided on the outer surface of the cylinder head 24.
a ..., 24a ... are provided. In addition, the crankcase 22 has an installation surface 22 on the lower surface of the crankcase 22.
At a, it is installed on the engine beds of various working machines. The crankcase 22 comprises a case body 25 cast and formed integrally with the cylinder block 23, and a side cover 26 joined to an open end of the case body 25. 26, both ends of a crankshaft 27 are rotatably supported via ball bearings 28 and 29 and oil seals 30 and 31. One end of the crankshaft 27 projects from the side cover 26 as an output shaft 27a, and the other end of the crankshaft 27 projects from the case body 25 as an accessory mounting shaft 27b.
Moreover, the flywheel 32 is attached to the accessory mounting shaft 27b.
On the outer surface of the flywheel 32, a cooling fan 35 for supplying cooling air to each part of the engine body 21 and the carburetor 34 is fixed by a screw member 36. An expression engine starter 37 is provided. The cylinder block 23 includes a piston 38
Is formed slidably, and a combustion chamber 40 facing the top of the piston 38 is formed between the cylinder block 23 and the cylinder head 24. An intake port 41 and an exhaust port 42 are formed in the cylinder head 24 so as to communicate with the combustion chamber 40, and an intake valve 43 for opening and closing the intake port 41 and the combustion chamber 40, and an exhaust port 42 and a combustion chamber. An exhaust valve 44 for opening and closing between the 40 is provided so as to be able to open and close. Further, an ignition plug 45 for exposing the electrode to the combustion chamber 40 is screwed to the cylinder head 24. A carburetor 34 is provided above the cylinder head 24.
Is connected, and the downstream end of the intake path 46 provided in the carburetor 34 is communicated with the intake port 41. In addition, the intake passage 46
Is connected to the carburetor 34,
The intake pipe 47 is connected to an air cleaner (not shown).
An exhaust pipe 48 communicating with the exhaust port 42 is connected to an upper portion of the cylinder head 24, and the exhaust pipe 48 is connected to an exhaust muffler 49. Further, a fuel tank 51 is disposed above the crankcase 22 so as to be supported by a bracket 50 protruding from the crankcase 22. The drive gear 5 is attached to the crankshaft 27 at a portion of the crankcase 22 near the side cover 26.
A driven gear 53 meshing with the drive gear 52 is fixed to a rotating shaft 54 having an axis parallel to the crankshaft 27, and both ends of the rotating shaft 54 are connected to a case body of the crankcase 22. It is rotatably supported via ball bearings 55 and 56 of the side cover 25 and the side cover 26. Thus, rotational power from the crankshaft 27 is transmitted to the rotating shaft 54 at a reduction ratio of に よ り by the driving gear 52 and the driven gear 53 meshed with each other. A valve operating mechanism 66 for opening and closing the intake valve 43 and the exhaust valve 44 includes an intake cam 57 and an exhaust cam 58 that are driven to rotate from the crankshaft 27 at a reduction ratio of 1/2, and the cams 57. Lifter 5 slidingly in contact with 58
9 and 60, push rods 62 and 63 pushed by lifters 59 and 60, and rocker arms 64 and 65 provided between the push rods 62 and 63 and the intake valve 43 and the exhaust valve 44. Referring also to FIG. 4, the rotating shaft 54 includes
An intake cam 57 and an exhaust cam 58 corresponding to the intake valve 43 and the exhaust valve 44 are provided, respectively. The lifter 59 operably supported by the cylinder block 23 is provided on the intake cam 57 and the exhaust cam 58. , 60 are in sliding contact. On the other hand, a working chamber 61 is formed in the cylinder block 23 and the cylinder head 24 so that upper portions of the lifters 59 and 60 project downward, and lower ends of push rods 62 and 63 disposed in the working chamber 61 are formed. The lifters 59 and 60 are in contact with each other. On the other hand, rocker arms 64 and 65 having one ends in contact with the upper ends of the intake valve 43 and the exhaust valve 44 which are spring-biased in the valve closing direction are attached to the cylinder head 24.
The rocker arms 6 are swingably supported.
The upper ends of the push rods 62, 63 are in contact with the other ends of the push rods 4, 65, respectively. In such a valve operating mechanism 66, the push rods 62, 63 are operated in the axial direction in accordance with the rotation of the intake cam 57 and the exhaust cam 58, and the rocker arms 64, 65 are swung in accordance with the axial movement of the push rods. The valve 43 and the exhaust valve 44 open and close. Referring also to FIG. 5, an eccentric shaft 67 provided at an eccentric position of the rotary shaft 54, the piston 38, and the crankshaft 27 are connected via a link mechanism 68. The link mechanism 68 has a connecting rod 7 having one end connected to the piston 38 via a piston pin 69.
0, a sub-rod 72 connected to the crankshaft 27 via the crank pin 71 and connected to the other end of the connecting rod 70, and a control rod connected to the sub-rod 72 at a position shifted from the connecting position of the connecting rod 70. 73 and an eccentric shaft 67 connected to the other end of the control rod 73. The sub-rod 72 has a semicircular first bearing portion 74 in the middle thereof, which is in sliding contact with a half circumference of the crank pin 71. Both ends of the sub-rod 72 have the other end of the connecting rod 70 and the control A pair of bifurcated portions 72a and 72b sandwiching one end of the rod 73 therebetween.
Are provided integrally. A semicircular second bearing portion 75 of the crank cap 76 is in sliding contact with the remaining half circumference of the crank pin 71, and the crank cap 76 is fastened to the sub rod 72. The other end of the connecting rod 70 is rotatably connected to one end of a sub-rod 72 via a connecting rod pin 77. The connecting rod 70 is inserted into a forked portion 72a at one end of the sub-rod 72. Both ends of the connecting rod pin 77 press-fitted into the other end are forked at the one end.
2a so as to be rotatable. One end of the control rod 73 is rotatably connected to the sub rod 72 via a sub rod pin 78. One end of the control rod 73 inserted into the forked portion 72b at the other end of the sub rod 72 is provided. Both ends of the sub-rod pin 78 that penetrates the portion in a relatively rotatable manner are rotatably supported by the forked portion 72a on the other end side. The eccentric shaft 67 is provided integrally with the rotary shaft 54 at the center between the intake cam 57 and the exhaust cam 58, and the two eccentric shafts 67 are viewed from the direction along the axis of the rotary shaft 54. One of the cams 57, 58 has a diameter that covers the entire intake side cam 57 and is formed integrally with the rotating shaft 54. On the other hand, the other end of the control rod 73 has a circular shaft hole 79 into which the eccentric shaft 67 is slidably fitted.
Is provided. With the rotation of the eccentric shaft 67 at a reduction ratio of の according to the rotation of the crankshaft 27, the link mechanism 68 causes the stroke of the piston 38 in the expansion stroke to be larger than the stroke in the compression stroke. Also works to increase
Thereby, a larger expansion work can be performed with the same intake air-fuel mixture amount, and the cycle thermal efficiency can be improved. A breather chamber 80 is formed in the engine body 22 above the eccentric shaft 67 of the rotating shaft 54.
That is, the case body 25 of the crankcase 22 of the engine body 22 is integrally provided with a breather housing 81 which is formed in a rectangular cylindrical shape and protrudes upward. The breather housing 81 and the breather housing 8
1 so as to cover the opening at the outer end of the breather housing 8.
A breather chamber 80 is formed by the cover plate 82 fastened to the casing 1 and the breather chamber 80 communicates with the inside of the crankcase 22 through an inlet 83 provided in the case main body 25 at a portion corresponding to the eccentric shaft 67. Further, the breather chamber 80 is provided on the cover plate 82.
Inside, a baffle plate 84 forming a maze is supported, and the breather gas that has passed through the maze is led out, for example, from an outlet 85 provided in the breather housing 81, and is led to the air cleaner via a pipe (not shown). The oil accompanying the breather gas while passing through the maze is subjected to gas-liquid separation, and the oil that has separated and falls into the lower portion of the breather chamber 80 is located at a position adjacent to the inlet 83. , And falls into the crankcase 22 from an oil supply hole 86 provided in the case main body 25, and the oil supply hole 86 is arranged at a position where oil is dropped onto the eccentric shaft 67. Next, the operation of this embodiment will be described. The power is transmitted from the crankshaft 27 at a reduction ratio of 1/2, and the rotary shaft 54 having an eccentric shaft 67 is
Since the intake-side and exhaust-side cams 57 and 58 that constitute a part of the valve operating mechanism 66 are provided, it is not necessary to provide a camshaft separately from the rotary shaft 54, so that the number of parts can be reduced and the The space for disposing the shaft is unnecessary, and the engine can be downsized.
In addition, since a dedicated camshaft is not required, a power transmission mechanism between the crankshaft 27 and the dedicated camshaft is not required, and mechanical noise and friction loss can be reduced. The rotary shaft 54 has one of the cams 57 and 58 on the intake side and the exhaust side, and one of the two cams 57 and 58 when viewed from the direction along the axis of the rotary shaft 54 (in this embodiment, the cam 57 on the intake side). An eccentric shaft 67 having a diameter covering the entire shape of the cam 57 and disposed between the cams 57 and 58 is provided integrally. For this reason, it is possible to provide the eccentric shaft 67 on the rotating shaft 54 without using the rotating shaft 54 as a crank structure, and it is possible to increase the processing accuracy of the eccentric shaft 67 and the cams 57 and 58, and to achieve light weight and high rigidity Can be formed with a rotating shaft. Further, above the eccentric shaft 67, the engine body 2
The case body 25 of the first crankcase 22 includes:
A breather chamber 80 is formed, and the breather chamber 8 is formed.
An oil supply hole 86 for dropping the oil separated from the breather gas by gas-liquid separation in the eccentric shaft 67 is provided. Accordingly, the oil separated from the breather gas in the breather chamber 80 drops on the eccentric shaft 67, and lubrication between the eccentric shaft 67 and the control rod 73 is made unnecessary while providing a dedicated lubricating device for the eccentric shaft 67. It is possible to reduce the size and weight of the engine. Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible. For example, in the above embodiment, the power reduced from the crankshaft 27 at a reduction ratio of 1/2
4, a stroke variable engine in which the stroke of the piston 38 in the expansion stroke is made larger than the stroke in the compression stroke has been described. The present invention is also applicable to an engine in which the eccentric shaft 67 is displaced by angularly displacing the 54 and thereby the compression ratio is made variable. As described above, according to the present invention, the oil separated from the breather gas is dropped on the eccentric shaft, so that it is not necessary to provide a lubricating device dedicated to the eccentric shaft, and the eccentric shaft and the control rod are not required. Allows for lubrication between
This can contribute to downsizing and weight reduction of the engine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of an engine. FIG. 2 is a longitudinal sectional view of the engine seen from the same direction as FIG. 1, and is a sectional view along line 2-2 in FIG. FIG. 3 is a sectional view taken along line 3-3 of FIG. 2; FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 2; FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG. 3; [Description of Signs] 21 ・ ・ ・ Engine body 27 ・ ・ ・ Crankshaft 38 ・ ・ ・ Piston 54 ・ ・ ・ Rotating shaft 67 ・ ・ ・ Eccentric shaft 69 ・ ・ ・ Piston pin 70 ・ ・ ・ Connecting rod 71 ・ ・ ・ Crank Pin 72 Sub rod 73 Control rod 80 Breather chamber 86 Oil supply hole

   ────────────────────────────────────────────────── ─── Continuation of front page    F term (reference) 3G013 AA00 AA02 AA04 AB00 BA03                       BC06                 3G015 AA00 AA02 AA04 AB00 BD11                       BD24 BE05 BF05 BF06 CA06                       DA02 DA05 DA11                 3G092 AA01 AA05 AA12 AC05 DD06                       DG03 FA50

Claims (1)

Claims: 1. A connecting rod (70) having one end connected to a piston (38) via a piston pin (69), and a crankshaft (22) rotatably supported by an engine body (21). 27) connected to the other end of the connecting rod (70) via a crank pin (71) and a sub rod (72) at a position shifted from the connecting position of the connecting rod (70). ) Is connected to a control rod (73) having one end connected thereto, and a rotating shaft (5) rotatably supported by the engine body (21).
4) In an engine having an eccentric shaft (67) provided at an eccentric position and connected to the other end of the control rod (73), the engine body (21) is provided above the eccentric shaft (67). A breather chamber (80) is formed, and oil separated from breather gas by gas-liquid separation in the breather chamber (80) is supplied to the eccentric shaft (6).
An engine characterized in that an oil supply hole (86) for dropping is provided in 7).