JPH10169716A - Engine with balancer spindle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain sufficient vibration damping performance, and also prevent the prolongation of the overall length of an engine, by arranging a balancer driving gear between a cam driving gear and a rear side crank arm, also an auxiliary balancer weight in the rear of a balancer input gear. SOLUTION: A balancer driving gear 13 and a balancer input gear 14 are externally and fittedly fixed to a crank shaft 7 and a balancer shaft 8 respectively, and the gears 13 and 14 are arranged on the same plane to be interlocked. A balance weight 15 of the balancer shaft is made to pass between the counterweights 17 and 17 of a fore and rear pair of crank arms 10 and 10. The gear 13 and an auxiliary balance weight 18 are arranged, between a cam driving gear 11 and the rear side crank arm 10, and the rear of the gear 14 respectively. Since thus the weight 18 is provided, sufficient vibration damping performance can be obtained, also the prolongation of the overall length of an engine can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an engine with a balancer shaft.

[0002]

2. Description of the Related Art FIG. 4 shows a prior art of an engine with a balancer shaft. This is performed as follows, as in the present invention. In other words, the crankshaft 107 and the balancer shaft 108 which are
And the cam shaft 109 are installed in parallel.
The parts near both ends of 108 and 109 are
The cam drive gear 111 is supported by the crankshaft 107 between a rear bearing portion 106b for supporting a portion near the rear end of the crankshaft 107 and a rear crank arm 110 supported by the front wall 104 and the rear wall 102, respectively. And the cam input gear 112 is externally fixed to the cam shaft 109, the cam drive gear 111 and the cam input gear 112 are arranged on the same plane, and the cam input gear 112 is interlocked with the cam drive gear 111. It is like that.

[0003] A balancer driving gear 113 is externally fitted and fixed to the crankshaft 107, and a balancer input gear 114 is externally fitted and fixed to the balancer shaft 108.
And the balancer input gear 114 are arranged on the same plane,
The balancer drive gear 113 is used to drive the balancer input gear 114.
And the balancer weight 115 of the balancer shaft 108 is connected to a pair of front and rear crank arms 110.
, Between the counter weights 117 and 117.

In this prior art, the balancer driving gear 11
3 is a front crank arm 110 and a front bearing 105b.
, And the rear crank arm 110 and the cam drive gear 111 are brought into close contact with each other. In this prior art,
In order to avoid interference between the lower end edge of the cylinder liner 120 and the cam input gear 112, it is necessary to increase the distance 122 between the cylinder center axis 121 and the cam drive gear 111, and furthermore, the front crank arm 110 and the front bearing A space for accommodating the balancer drive gear 113 is required between the first and second portions 105b. For this reason, the cam drive gear 111 and the cam input gear 112 are made thinner to suppress an increase in the overall length of the engine. Further, there is no place on the balancer shaft 118 for disposing the auxiliary balancer weight.

[0005]

According to the above prior art, there is the following problem (see FIG. 4). It is necessary to make the cam drive gear 111 and the cam input gear 112 thinner in order to suppress an increase in the overall length of the engine. These gears 111 and 112 receive a large reaction force when the cam 123 is lifted up, but their life is short because they are thin.

Since there is no place for arranging the auxiliary balancer weight on the balancer shaft 118, sufficient vibration damping performance cannot be obtained in many cases.

The object of the first invention is as follows. The thickness of the cam drive gear and cam input gear can be increased without increasing the overall length of the engine. Auxiliary balancer weights can be placed on the balancer shaft. To prevent the overall length of the engine from being lengthened by the arrangement of the auxiliary balancer weights. The object of the second invention is as follows in addition to the object of the first invention. To facilitate the work of meshing the balancer drive gear and balancer input gear. The object of the third invention is as follows in addition to the object of the second invention. To facilitate mounting of the rear wall of the crankcase. The object of the fourth invention is as follows in addition to the object of any of the first to third inventions. To prevent the number of parts from increasing due to the addition of the auxiliary balancer weight.

[0008]

[Means for Solving the Problems]

(First invention) In the first invention, as shown in FIG. 1, a crankshaft 7, a balancer shaft 8, and a camshaft 9 which are directed in the front-rear direction are installed in parallel in a crankcase 1, and each of these shafts 7. 8.
9 is supported by the front wall 4 and the rear wall 2 of the crankcase 1 respectively, and a rear bearing 6b for bearing the rear end of the crankshaft 7 and the rear crank arm 1 are provided.
0, the cam drive gear 11 is externally fixed to the crankshaft 7, the cam input gear 12 is externally fixed to the camshaft 9, and the cam drive gear 11 and the cam input gear 12 are arranged on the same plane. The cam input gear 12 is interlocked with the cam drive gear 11.

A balancer drive gear 13 is externally fitted and fixed to the crankshaft 7, and the balancer input gear 1 is fixed to the balancer shaft 8.
4, the balancer drive gear 13 and the balancer input gear 14 are arranged on the same plane, and the balancer input gear 14 is interlocked with the balancer drive gear 13,
The balancer weight 15 of the balancer shaft 8 passes between the counterweights 17 of the pair of front and rear crank arms 10.

The engine with the balancer shaft is characterized as follows. That is, the balancer driving gear 13 is disposed between the cam driving gear 11 and the rear crank arm 10, and the auxiliary balancer weight 18 is disposed at the rear of the balancer input gear 14.

(Second Invention) In a second invention, as shown in FIG. 1, in the first invention, an opening 16 is provided in a rear portion of the crankcase 1, and a rear wall 2 of the crankcase 1 is connected to an opening edge of the crankcase 1. So that it can be attached to and detached from the part 3.
The rear wall 2 of the crankcase 1 is fitted to the opening edge 3 of the crankcase 1 while the rear end portions of the 8.9 are fitted in rear bearings 6a, 6b, 6c provided on the rear wall 2 of the crankcase 1. It is characterized in that it can be mounted.

(Third Invention) In a third invention, as shown in FIG. 1, in the second invention, the rear end portion 19 of the balancer shaft 8 has a length protruding rearward from the rear bearing portion 6c, and the protruding portion is formed. It is characterized in that it is formed in a tapered shape.

(Fourth Invention) In a fourth invention, as shown in FIG. 1, in any one of the first invention to the third invention, the balancer input gear 14 and the auxiliary balancer weight 18 are integrally formed. Features.

[0014]

Actions and effects of the present invention

(First Invention) The first invention has the following effects (see FIG. 1). Since the balancer drive gear 13 is disposed between the cam drive gear 11 and the rear crank arm 10, the cam is moved from the cylinder center axis 21 necessary to avoid interference between the lower edge of the cylinder liner 20 and the cam input gear 12. Drive gear 11
The balancer drive gear 13 can be accommodated within the separation distance 22 up to, and the space for accommodating the balancer drive gear 13 that was conventionally required between the front crank arm 10 and the front bearing portion 5b is not required, and the engine is not required. The cam drive gear 11 and the cam input gear 12 can be made thicker by the accommodation gap without increasing the overall length of the cam drive gear 11. These gears 11.1
2 receives a large reaction force when the cam 23 is lifted up.

Since the auxiliary balancer weight 18 is provided at the rear of the balancer input gear 17 fixed to the balancer shaft 8, sufficient vibration damping performance can be obtained.

By increasing the thickness of the cam drive gear 11, the auxiliary balancer weight 18 can be accommodated in a space formed on the same plane as the cam drive gear 11, so that the overall length of the engine is increased by the arrangement of the auxiliary balancer weight 18. Can be prevented.

(Second Invention) The first invention has the following functions and effects in addition to the functions and effects of the second invention (see FIG. 1). Not only the cam drive gear 11 and the cam input gear 12 but also the balancer drive gear 13 and the balancer input gear 14 have openings 16.
Since the gears are located in the vicinity, the gear meshing operation can be easily performed while checking these mating marks.

(Third Invention) The third invention has the following effects in addition to the effects of the second invention (see FIG. 1). When the rear wall 2 is mounted on the opening edge 3 of the crankcase 1, the rear end 19 of the balancer shaft 8 is tapered even if there is some deviation between the direction of the rear bearing 6 c and the direction of the balancer shaft 8. Because of this, it fits smoothly into the rear bearing 6c, so that the rear wall 2 can be easily mounted.

(Fourth Invention) The fourth invention has the following function and effect in addition to the functions and effects of any of the first to third inventions (see FIG. 1). Since the auxiliary balancer weight 18 is integrated with the balancer input gear 14, an increase in the number of components due to the addition of the auxiliary balancer weight 18 can be prevented.

[0020]

Embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 3 illustrate a vertical single-cylinder four-cycle partially liquid-cooled diesel engine according to an embodiment of the present invention. The configuration of this engine is as follows. As shown in FIG.
4 are integrally formed to form a cylinder block, a cylinder head 25 is mounted on the upper part, and a head cover 26 is mounted on the upper part. The cylinder liner 20 is fitted in the cylinder 24. An auxiliary combustion chamber 27 is provided in the cylinder head 25.

A cylinder jacket 28 is provided inside the wall of the cylinder 24, and a sub-chamber 29 is formed around the sub-combustion chamber 27. As shown in FIG. 3, a fan case 31 containing a flywheel fan 30 is arranged on the front side of the cylinder block, and a radiator 32 is arranged above the fan case 31. Coolant that has passed through the cylinder jacket 28 and the sub-chamber jacket 29 is introduced into the radiator 32. Some of the cooling air generated by the flywheel fan 30 passes around the cylinder 24 and
4 is air cooled. In addition, part of the cooling air passes around the radiator 32 and radiates the cooling liquid passing through the radiator 32.

In this embodiment, as shown in FIG. 1, a crankshaft 7, a balancer shaft 8, and a cam shaft 9 which extend in the front-rear direction are installed in parallel in a crankcase 1, and these shafts 7
・ The part near both ends of 8.9 is the front wall 4 of the crankcase 1
A cam drive gear 11 is externally fitted and fixed to the crankshaft 7 between a rear bearing portion 6b for supporting a portion near the rear end of the crankshaft 7 and the rear crank arm 10. The cam input gear 12 is externally fixed to the cam shaft 9, the cam drive gear 11 and the cam input gear 12 are arranged on the same plane, and the cam input gear 12 is interlocked with the cam drive gear 11.

The front end portions of the shafts 7, 8 and 9 are provided at front bearing portions 5a, 5b, and 5 provided on the front wall 4 of the crankcase 1.
5c, and the rear end portions are respectively supported by rear bearing portions 6a, 6b, 6c provided on the rear wall 2. The cam drive gear 11 and the cam input gear 12 directly mesh with each other. As shown in FIG. 2, a governor input gear 35 is provided on the Kim input gear 12, and a pair of cams 23 are provided on the cam shaft 9. As shown in FIG.
, The fuel injection pump 33 is linked, and the other cam 23 is linked with the valve train 34. Cam input gear 1
2, the governor input gear 35 is directly meshed.

A balancer driving gear 13 is externally fitted and fixed to the crankshaft 7, and the balancer input gear 1 is fixed to the balancer shaft 8.
4, the balancer drive gear 13 and the balancer input gear 14 are arranged on the same plane, and the balancer input gear 14 is interlocked with the balancer drive gear 13,
The balancer weight 15 of the balancer shaft 8 passes between the counterweights 17 of the pair of front and rear crank arms 10.

In this embodiment, the balancer drive gear 13 is provided so that the cam drive gear 11 and the cam input gear 12 can be made thicker without increasing the overall length of the engine.
Is disposed between the rear side of the cam drive gear 11 and the crank arm 10, and an auxiliary balancer weight 18 is disposed at the rear of the balancer input gear 14.

In this embodiment, the balancer driving gear 13
In order to facilitate the meshing operation of the input gear 14 and the balancer 14, an opening 16 is provided at the rear of the crankcase 1 so that the rear wall 2 of the crankcase 1 can be attached to and detached from the opening edge 3 of the crankcase 1. A rear bearing portion 6 in which a rear end portion of each shaft 7, 8, 9 is provided on a rear wall 2 of the crankcase 1.
The rear wall 2 of the crankcase 1 can be attached to the opening edge portion 3 of the crankcase 1 while being fitted inside a, 6b, 6c.

In this embodiment, in order to facilitate mounting of the rear wall 2 of the crankcase 1, the rear end 1 of the balancer shaft 8 is provided.
Reference numeral 9 denotes a length protruding rearward from the rear bearing 6c, and the protruding portion is formed in a tapered shape.

In this embodiment, the balancer input gear 14 and the auxiliary balancer weight 18 are used to prevent the number of parts from increasing due to the addition of the auxiliary balancer weight 18.
And are integrally molded. These are formed by integral casting.

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view of an engine according to an embodiment of the present invention.

FIG. 2 is a longitudinal rear view of the engine of FIG. 1;

FIG. 3 is a vertical sectional side view of the engine of FIG. 1;

FIG. 4 is a vertical sectional view of an engine according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Crankcase, 2 ... Rear wall, 3 ... Opening edge part, 4 ... Front wall, 6a, 6b, 6c ... Rear bearing part, 7 ... Crankshaft,
8: balancer shaft, 9: cam shaft, 10: crank arm,
11 cam drive gear, 12 cam input gear, 13 balancer drive gear, 14 balancer input gear, 15 balancer weight, 16 opening, 17 counter weight, 1
8: auxiliary balancer weight, 19: rear end.

Claims (4)

[Claims] 1. A crankshaft (7), a balancer shaft (8) and a camshaft (9) extending in the front-rear direction are installed in parallel in a crankcase (1), and these shafts (7) and (8) The rear end of the crankcase (1) is supported by the front wall (4) and the rear wall (2) of the crankcase (1), and the rear end of the crankshaft (7) is supported. (6b) and rear crank arm (10)
The cam drive gear (11) is externally fixed to the crankshaft (7), the cam input gear (12) is externally fixed to the camshaft (9), and the cam drive gear (11) and the cam input gear are fixed. The gear (12) is arranged on the same plane, and the cam drive gear (11)
The balancer drive gear (13) is externally fitted and fixed to the crankshaft (7), and the balancer input gear (14) is externally fitted and fixed to the balancer shaft (8).
3) and the balancer input gear (14) are arranged on the same plane, and the balancer drive gear (13) is
(14) are linked to each other, and the balancer weight (15) of the balancer shaft (8) is paired with the front and rear crank arms (10)
In the engine with the balancer shaft, which passes between the counterweights (17) and (17) of (10), the balancer drive gear (13) is connected to the cam drive gear (11) and the rear crank arm (10). And an auxiliary balancer weight (18) arranged at the rear of the balancer input gear (14). 2. The engine with a balancer shaft according to claim 1, wherein an opening (16) is provided at a rear portion of the crankcase (1).
The rear wall (2) of the crankcase (1) can be attached to and detached from the opening edge (3) of the crankcase (1).
(7), (8) and (9) while the rear end portion is fitted in rear bearing portions (6a), (6b) and (6c) provided on the rear wall (2) of the crankcase (1). The rear wall (2) of the crankcase (1) can be attached to the opening edge (3) of the crankcase (1).
An engine with a balancer shaft. 3. The engine with a balancer shaft according to claim 2, wherein the rear end portion (19) of the balancer shaft (8) has a length protruding rearward from the rear bearing portion (6c), and the protruding portion has a tapered shape. An engine with a balancer shaft formed in 4. The engine with a balancer shaft according to claim 1, wherein the balancer input gear (14) and the auxiliary balancer weight (18) are integrally formed. Engine with balancer shaft.