JP3206114B2 - Engine with balancer shaft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine with a balancer shaft.

[0002]

2. Description of the Related Art Some automobile engines and the like rotate a balancer shaft having an eccentric weight in synchronization with the rotation of the engine (JP-A-63-167145).
Publication No.).

A conventional engine with a balancer shaft is:
As shown in FIG. 5, the eccentric weight 32 of the balancer shaft 31 is disposed at the engine center, and the eccentric weight 3
The inertial force Fb of the piston, the connecting rod and the like is canceled by the inertial force Fb given by 2, and the fundamental order vibration having a frequency twice as high as the engine rotation is suppressed.

[0004] The eccentric weight 32 is arranged at the engine center, and the distance between the point of action of each inertial force Fe, Fb and the center of gravity of the power plant is equalized to offset the pitching moment with respect to the power plant.

[0005]

However, in such a conventional engine with a balancer shaft,
Since the eccentric weight 32 must be disposed at the engine center, not only the balancer shaft 31 becomes longer, but also, for example, the oil pan becomes larger when the balancer shaft 31 is housed in the oil pan. invited.

An object of the present invention is to reduce the size of an engine with a balancer shaft by focusing on the above points.

[0007]

According to a first aspect of the present invention, there is provided an engine with a balancer shaft having a power transmission mechanism for disposing a balancer shaft having an eccentric weight in parallel with a crankshaft and transmitting rotation of the crankshaft to the balancer shaft. A main eccentric weight is formed on the balancer shaft so as to be offset in the axial direction of the balancer shaft with respect to the engine center, and the sub eccentric weight is eccentric with respect to the main eccentric weight with respect to the rotation axis of the balancer shaft in a direction radially opposite to the main eccentric weight. Offset to the side far from the center and fix
Engine reciprocating motion system, such as motor and connecting rod, main eccentricity
Inertia force acting on each of the weight and sub-eccentric weight
The power, including the engine, almost offset each other
The engine reciprocating system relative to the center of gravity of the plant,
Each of the main eccentric weight and the sub eccentric weight
The pitching moments given by
So that the main eccentric weight and the sub eccentric weight
Set the mass and position of the site . The second invention is the first invention
In the invention, the mass of the main and sub eccentric weights
And the position are set based on the following equation . Fe + Fs = Fm Fe × Le + Fs × Ls = Fm × Lm where, Fe: engine and piston, connecting rod, etc.
Inertia force acting on the backward movement system Fs: Inertia force acting on the sub-eccentric weight or its resultant force Fm: Inertial force acting on the main eccentric weight or its resultant force Le: Transmission connected to the engine body and its rear part
Engine Sen from the center of gravity of the power plant, including the Deployment
Distance to the coater Ls: transmitter for connecting the engine body and its rear
From the center of gravity of the power plant including the
Distance Lm to the point of action of the inertial force Fs acting on the engine: The transmission connected to the engine body and the rear
From the center of gravity of the power plant including the
This is the distance to the point of action of the inertial force Fm acting on the gate .

[0008]

[0009]

According to the first and second aspects of the present invention, the sub eccentric weight is moved to the main eccentric weight with respect to the rotation axis of the balancer shaft .
Eccentric to the opposite side in the radial direction, and offset from the engine center to the side farther than the main eccentric weight , the engine reciprocating motion system such as piston and connecting rod,
Works on main eccentric weight and sub eccentric weight
The inertia forces almost cancel each other, and the power
The engine reciprocating system and the main
Each of the eccentric weight and the sub eccentric weight
The pitching moments they give almost cancel each other out.
The main eccentric weight and the sub eccentric weight
By setting the mass and position of the engine,
Sub-eccentric weights are added to the power plant consisting of the engine and the transmission , by suppressing the order vibration and subtracting the difference between the pitching moment given by the main eccentric weight and the pitching moment generated by the engine reciprocating motion system such as the piston and connecting rod into the power plant consisting of the engine and the transmission. Offset by the pitching moment.

In this manner, by disposing the eccentric weight of the balancer shaft away from the engine center, the length of the balancer shaft can be reduced and the engine can be made more compact.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, a crankshaft 2 is supported at a lower portion of an engine block 1 provided in an in-line four-cylinder engine via five bearing caps 11. The balancer shaft 3 is supported via a balancer housing 12.

An upper oil pan 21 and a lower oil pan 22 are attached to a lower portion of the engine block 1. The lubricating oil stored in the lower oil pan 22 is sucked up by an oil pump via an oil strainer (not shown), and after lubricating various parts of the engine, the upper oil pan 2
1 returns to the lower oil pan 22.

The balancer housing 12 is disposed between the lower oil pan 22 and the crankshaft 2. This engine is mounted horizontally in the engine room of the vehicle. The engine is located behind the lower oil pan 22 (leftward for the vehicle) and below the upper oil pan 21, and has an exhaust pipe 23 and a center member of the vehicle body. 24 are arranged.

Each balancer shaft 3 is formed with two journal portions 4 and 5, and the balancer housing 12 is formed with two pairs of bearings 18 and 19 that support the journal portions 4 and 5.

Each balancer shaft 3 is arranged in parallel with the crankshaft 2, and the rotational force of the crankshaft 2 is
The reverse gear 16, which is transmitted to one of the balancer shafts 3 via the sprocket 13, the chain 14, and the sprocket 15, is coupled to the two balancer shafts 3, and meshes with each other.
17 to the other balancer shaft 3.
As a result, a power transmission mechanism that drives each balancer shaft 3 to rotate in opposite directions at twice the speed of the crankshaft 2 is configured.

In FIG. 1, # 1 bulk center is # 1
The cylinder is located forward of the cylinder, and the # 2 bulk center is located between the # 1 cylinder and the # 2 cylinder. In the case of this four-cylinder engine, the engine center is on the # 3 bulk center located between the # 2 cylinder and the # 3 cylinder. The engine center is located at the center of the crankshaft 2,
It is located at the center of the four pistons and connecting rods, and is the point of action of the inertial force provided by the reciprocating system of the engine.

Each balancer shaft 3 is offset in the axial direction forward of the engine center. In the balancer housing 12, each bearing 18 is arranged on the # 1 bulk center, and each bearing 19 is arranged on the # 2 bulk center.

Each balancer shaft 3 has a pair of main eccentric weights 6 and 7 formed with a rear journal portion 5 interposed therebetween. Each of the main eccentric weights 6, 7 is formed eccentric in the same direction with respect to the rotation axis of each balancer shaft 3, and cancels the inertial force of the piston, the connecting rod, and the like.

Each balancer shaft 3 has a sub-eccentric weight 8 formed between the front journal portion 4 and the front main eccentric weight 6. Each sub eccentric weight 8 is eccentric with respect to the rotation axis of each balancer shaft 3 in a direction opposite to each of the main eccentric weights 6 and 7.

Thus, each of the main eccentric weights 6, 7
Are formed so as to be offset from the engine center in the axial direction, and each sub-eccentric weight 8 is formed so as to be offset from the engine center in the axial direction further away from the main eccentric weights 6 and 7.

In FIG. 4, Fe is the inertial force acting on the reciprocating motion system of the engine such as the piston and the connecting rod, and the point of action is at the engine center. If Fm is the resultant of the inertial forces acting on the main eccentric weights 6 and 7 and Fs is the resultant of the inertial forces acting on the sub-eccentric weights 8, Fe + Fs = Fm (1) Also, the transmission connected to the engine body and the rear part is The distance of the engine center from the center of gravity of the power plant including the engine is Le, the distance of the point of action of the inertial force Fm acting on each of the main eccentric weights 6 and 7 is Lm, and the distance of the inertial force Fs acting on each of the sub eccentric weights 8 is Ls. Then, Fe · Le + Fs · Ls = Fm · Lm (2) The masses and dimensions of the main eccentric weights 6 and 7 and the sub eccentric weights 8 are set so as to satisfy the above equations (1) and (2). As a result, the inertial force acting on the engine reciprocating system is canceled, and the secondary vibration of the engine is suppressed. The difference between the pitching moment given by the main eccentric weights 6 and 7 to the center of gravity of the power plant and the pitching moment generated by the engine reciprocating system such as the piston and the connecting rod is the pitching moment given by each sub eccentric weight 8. Offset by

By offsetting each balancer shaft 3 in front of the engine center in this way, the length of the lower oil pan 22 that accommodates the balancer housing 12 is shortened, and these are arranged near the lower oil pan 22. Interference with the exhaust pipe 23 or the center member 24 of the vehicle body.

[0023]

As described above, according to the present invention, the main eccentric weight is formed on the balancer shaft so as to be offset in the axial direction of the balancer shaft with respect to the engine center, and the sub-eccentric weight is formed with respect to the rotation axis of the balancer shaft. Eccentric to the opposite side in the radial direction, and offset to the side farther from the engine center to form an engine such as a piston and connecting rod.
Reciprocating motion system, main eccentric weight, sub eccentric weight
Inertia forces acting on each other are almost offset each other
At the center of gravity of the power plant including the engine,
Engine reciprocating system, main eccentric weight,
Pitching moments given by each of the eccentric weights
The main eccentric wedges so that
Weight and position of the sub-eccentric weight
And for, as well as shortening the length of the balancer shaft,
The engine can be made more compact, and the layout for mounting the engine on a vehicle can be made easier.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an engine showing an embodiment of the present invention.

FIG. 2 is a perspective view of the engine.

FIG. 3 is a perspective view of the balancer shaft.

FIG. 4 is a layout diagram of a balancer shaft.

FIG. 5 is a layout view of a balancer shaft showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine block 2 Crankshaft 3 Balancer shaft 6 Main eccentric weight 7 Main eccentric weight 8 Sub eccentric weight 21 Upper oil pan 22 Lower oil pan

(56) References JP-A-3-168445 (JP, A) JP-A-5-172187 (JP, A) JP-A-1-102545 (JP, U) (58) Fields surveyed (Int .Cl. ⁷ , DB name) F16F 15/26 F02B 77/00

Claims (2)

(57) [Claims] 1. An engine with a balancer shaft having a power transmission mechanism for transmitting rotation of a crankshaft to a balancer shaft, wherein a balancer shaft having an eccentric weight is arranged in parallel with the crankshaft. The offset eccentric weight is formed in the axial direction of the balancer shaft, and the sub eccentric weight is eccentric to the opposite side in the radial direction with respect to the main eccentric weight with respect to the rotation axis of the balancer shaft, and is offset to the side far from the engine center. , Piston and connecting rod engines
Reciprocating motion system, main eccentric weight, sub eccentric weight
Inertia forces acting on each other are almost offset each other
At the center of gravity of the power plant including the engine,
Engine reciprocating system, main eccentric weight,
Pitching moments given by each of the eccentric weights
The main eccentric wedges so that
Weight and position of the sub-eccentric weight
An engine with a balancer shaft. 2. The mass of the main and sub eccentric weights.
And the position is set based on the following formula.
The engine with a balancer shaft according to claim 1 . Fe + Fs = Fm Fe × Le + Fs × Ls = Fm × Lm where, Fe: engine and piston, connecting rod, etc.
Inertia force acting on the backward movement system Fs: Inertia force acting on the sub-eccentric weight or its resultant force Fm: Inertial force acting on the main eccentric weight or its resultant force Le: Transmission connected to the engine body and its rear part
Engine Sen from the center of gravity of the power plant, including the Deployment
Distance to the coater Ls: transmitter for connecting the engine body and its rear
From the center of gravity of the power plant including the
Distance Lm to the point of action of the inertial force Fs acting on the engine: The transmission connected to the engine body and the rear
From the center of gravity of the power plant including the
This is the distance to the point of action of the inertial force Fm acting on the gate .