JPH01271608A - Engine structure with balancer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine equipped with a balancer for vibration reduction and an oil return or breather communication path that communicates the interior space of the head cover with the inside of the crankcase. .

(Prior art) If there is a balance weight directly below the communication path, there is a problem in that the dripping oil receives the impact or centrifugal force of the balance weight, scatters, and is agitated with air, resulting in air being mixed into the oil. .

To prevent this, a balancer is installed outside the communication path (Japanese Patent Application Laid-Open No. 6L-104114), and an oil baffle is installed below the communication path to guide the oil so that the oil avoids the balancer. (Jitsukai Showa 8l-
77448) are known.

(Problems to be Solved by the Invention) Among the above-mentioned conventional techniques, the former technique has the disadvantage that the balancer is located outside the communication path, making the engine wider and larger; However, the provision of the oil baffle not only complicates the structure, but also has the disadvantage that the installation location across the communication is limited to the position of the supporting wall where the oil baffle can be formed, that is, the end of the cylinder row or between the cylinders.

Therefore, it is necessary to form a communication path that has a simple structure and fewer restrictions on installation locations without increasing the size of the engine.

(Means for Solving the Problems) The present invention has been made by focusing on the fact that if the oil does not collide with or come into contact with the balance weight of the balancer, the degree of scattering effect and agitation with air will be small. , a balancer that reduces vibrations caused mainly by the excitation force caused by the reciprocating mass of a multi-cylinder engine is pivotally supported on the side of the cylinder block parallel to the crankshaft, and the inside of the head cover communicates with the inside of the crankcase. In an engine equipped with a balancer, the balancer has a journal part and a balance weight part connected to the balancer shaft part at appropriate positions, and the journal part is connected to the end of the cylinder row or The balancer shaft is supported by a journal bearing provided on a support wall between the cylinders, and the communication passage is opened on the side of the cylinder avoiding the adjacent journal bearing and balancer weight.

(Function) With the above means, the falling oil is blocked by the support wall or journal bearing, so it does not fall or come into contact with the balance weight part, and the oil falling on the balancer shaft part is blocked by the support wall or the journal bearing. Since the oil has a circular cross section, the impact or centrifugal force acting on the oil is weak, and the ratio of stirring with air is small, so air is not mixed into the oil.

(Example) An example will be described below with reference to the drawings. In the figure, l
is a cylinder block with four cylinders 2a, 2bs
2c, 2d, and a water jacket 3.3' is formed around each cylinder. The lower part of the cylinder block l is a crankcase 4, and supporting walls 5a, 5b, 5c, 5d for supporting the crankshaft in a direction orthogonal to the crankshaft are provided at both ends of the cylinder row and between each cylinder.
5e is provided.

The balancer 6 is provided parallel to the crankshaft on the side of the cylinder block l, and includes a large-diameter journal portion 6b and a balance weight portion 6 on an extension of a small-diameter balancer shaft portion 6a.
C are connected in series, and journal portions 6b are provided at both ends of the balance weight portion 6C. Journal bearings 7as, 7bs, 7dq on support walls other than the center support wall 5C
7e is attached to support the balancer 6, which is driven by the crankshaft via an interlocking device (not shown).

A balancer shaft 6a is located on the side of the inner cylinders 2b and 2c, and as is clear from FIG. 1, a communication passage 8 passing through the cylinder block l is provided above the balancer shaft 6a. , the communication path 8 communicates with the space inside the head cover via a cylinder head (not shown) at an upper position.

When the engine is operated, the balancer 6 also rotates, and the centrifugal force applied to the balance weight portion 6C reduces vibrations caused by the excitation force due to the reciprocating mass. At this time, both ends of the balance weight part 6C are journal bearings 'las 7
Since it is supported by bq 7d and 7e, shaft vibration is reliably prevented.

The blow-by gas and oil are circulated through the communication path 8, and the oil falls from inside the head cover through the cylinder head and the communication path 8 into the crankcase 4. At this time, the oil does not fall onto the balance weight part 6c because it is blocked by the support wall or the journal bearing, but falls onto the balancer shaft part Ba, and since the shaft part 8a has a small diameter and a circular cross section, the oil is splashed away. The force of shaking off the oil due to centrifugal force is weak, and the scattering force is much smaller than when the oil falls onto the large-diameter, non-circular balance weight part 6C.

Therefore, the oil is less likely to be stirred together with the air, and the amount of air mixed into the oil is also small.

(Effects of the invention) As described above, since the balancer is provided below the communication path, the width of the engine does not need to be increased, and since the portion facing the communication path is made of a small-diameter balancer shaft, the falling oil The oil is not stirred or mixed with air, so air is not mixed into the oil and there is no risk of degrading the lubricating performance. Furthermore, since the balance weight part is supported by a journal bearing, shaft vibration is reliably prevented.

[Brief explanation of the drawing]

1 is a cross-sectional view taken along the line I--I in FIG. 3, FIG. 2 is a side view, and FIG. 3 is a cross-sectional view taken along the line ■--■ in FIG. 2a-2d...
・Cylinder 4...Crankcase 5a to 5e
...Support wall 6...Balancer 6a...Balancer shaft part 6b...Journal part 6c...
Balance weight part 8...Communication path Fig. 2 4 ”M Fig. 3

Claims (1)

[Claims] A balancer that reduces vibrations caused mainly by the excitation force caused by the reciprocating mass of a multi-cylinder engine is pivoted on the side of the cylinder block parallel to the crankshaft, communicating between the inside of the head cover and the inside of the crankcase. In an engine with a balancer that has a communication path that opens toward the road,
The balancer has a journal part and a balance weight part arranged in series on the balancer shaft part, and the journal part is supported by a journal bearing provided at the end of the cylinder row or on the support wall between the cylinders, and An engine structure with a balancer, characterized in that the communication passage is opened on the side of the cylinder avoiding the journal bearing part and balancer weight part to which the balancer shaft part is adjacent.