JPH063173Y2 - Inter-cylinder sealing device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an inter-cylinder seal device for an internal combustion engine having a plurality of cylinders.

(Prior Art) In a two-cycle internal combustion engine having a plurality of cylinders, crankcases in the respective cylinders are provided adjacent to each other, and a crankshaft is supported through the crankcases.

In this type of internal combustion engine, a seal is provided at a partition wall portion between adjacent crankcases so that the interiors of the crankcases do not communicate with each other, and as the seal, an oil seal 1 as shown in FIG. 2 is conventionally used. Or third
A labyrinth seal 2 as shown is used.

That is, a crankshaft 6 which passes through a partition wall 5 that partitions adjacent crankcases 3 and 4 is supported by a crank bearing 7, and an oil seal 1 or a labyrinth seal 2 is provided on one side surface of the crank bearing 7.

The oil seal 1 is made of rubber and has a generally U-shaped cross section, and the outer peripheral surface thereof is the crankshaft insertion hole 8 of the partition wall portion 5.
The inner peripheral surface of the crankshaft 9 is closely attached to the inner peripheral surface of the crankshaft 7, and the side surface of the outer peripheral surface of the crankshaft 7 is freely contactable with the outer peripheral surface of the crankshaft 9.

The labyrinth seal 2 has an outer peripheral surface closely contacted with the inner peripheral surface of the crankshaft insertion hole 8 of the partition wall 5, a side surface freely contactable with a side surface of the outer ring 7A of the crank bearing 7, and a slit portion of the inner peripheral surface of the crankshaft. It is provided at a slight interval on the circumferential surface of 9.

(Problems to be solved by the invention) However, in the case of the oil seal 1 shown in FIG. 2, since the oil seal 1 is made of rubber, it is easily affected by heat,
The cost will increase if the measures are taken. In addition, when the grease runs out, the grease is instantly destroyed, which is dangerous depending on how the internal combustion engine is used.

When the labyrinth seal 2 shown in FIG. 3 is used, it may come into contact with the peripheral surface of the crankshaft 9 due to assembly or manufacturing errors. If a clearance is provided so as not to contact the labyrinth seal 2, the sealing effect will be significantly reduced. It will be.

Further, both the oil seal 1 and the labyrinth seal 2 require a predetermined space in the axial direction due to the sealing principle, and therefore, when the crankshaft 6 is assembled, the space must be increased by the amount corresponding to the seal.
As a result, there is a problem that the weight of the internal combustion engine increases and the generated couple also increases.

In view of this, the present invention can obtain an internal combustion engine which has no thermal problem, can improve the sealing performance between crankcases, can significantly shorten the axial length, and can be reduced in cost and can be reduced in size and weight. The purpose of the present invention is to provide an inter-cylinder seal device that can be used.

[Constitution of device]

(Means for Solving the Problems) In order to solve the problems of the above-mentioned conventional technology, the present invention has a plurality of cylinders, and a crankshaft that penetrates a partition wall between adjacent crankcases is supported by a crank bearing. In an internal combustion engine, an annular plate is provided in the crank bearing so as to face one side surface of an outer ring so as to be movable in a small range in the axial direction. It is characterized in that it can be brought into close contact with one side surface, and the other surface can be brought into close contact with at least one of the crankshaft end surface and the partition wall contact surface when moving in the other direction.

(Operation) When the pressure in the crankcase on the crank bearing side becomes high, the annular plate moves so as to come into close contact with either or both of the crankshaft end surface and the partition wall contact surface, and is sealed. When the pressure in the case becomes high, the annular plate is moved and sealed so as to come into close contact with either one or both of the inner ring and the outer ring of the crank bearing.

(Embodiment) Hereinafter, the present invention will be described with reference to an embodiment shown in FIG. 1, and members common to those in FIGS. 2 and 3 will be described using the same reference numerals.

The outer ring 7A of the crank bearing 7 is press-fitted into the crankshaft insertion hole 8 of the partition wall 5 that divides the crankcases 3 and 4, and the inner ring 7B is press-fitted onto the peripheral surface of the crankshaft 6.

An abutting surface 10 is provided so as to face the inner peripheral side surface of the crankshaft insertion hole 8 on one side of the crank bearing 7, and a groove 11 is formed in the groove 11, and an annular plate 12 as a sealing material is formed in the groove 11. The outer peripheral part of is fitted. The inner circumference of the center hole 12A of the annular plate 12 is the crankshaft 6
Has an inner diameter as close as possible to the peripheral surface of the groove 11 and is movably provided within the axial width of the groove 11 by a small amount in the axial direction. The outer peripheral side surface of the groove 11 can be brought into close contact with the contact surface 10. At the same time, the inner peripheral side surface is in close contact with the end surface 9A of the crankshaft 9.

As the material of the annular plate 12, a synthetic resin plate can be selected including a metal plate in consideration of sealing property and increase in natural frequency.

Further, although the contact surface 10 is formed by the inner peripheral side surface of the contact plate 13 fixed to the partition wall portion 5 in the illustrated embodiment, when the contact plate 13 is used including the way of providing the contact surface 10. The attachment structure of the contact plate 13 can employ appropriate means such as screw fixing, screwing, welding and the like.

Next, the operation of the above embodiment will be described.

When the pressure inside the crankcase 3 on the crank bearing 7 side becomes high, the annular plate 12 moves so as to come into close contact with either the contact surface 10 of the partition wall portion 5 or the end surface 9A of the crankshaft 9, or both. Sealed. In this case, when they are in close contact with each other, they function as a kind of mechanical seal, and a complete sealing action is performed, and when they are in close contact with either the contact surface 10 or the end surface 9A of the crankshaft 9, they are a kind of labyrinth seal. Function.

When the pressure in the crankcase 4 on the opposite side becomes high, the annular plate 12 moves to the crank bearing 7 side and is closely sealed to the side surface of the inner ring 7B or the outer ring 7A of the crank bearing 7, or both side surfaces. . In this case, when they are in close contact with each other, they function as a kind of mechanical seal, and when they are in close contact with either one, they function as a kind of labyrinth seal.

Therefore, even if an error occurs during assembly, the sealing performance is not impaired. Even if the outer peripheral side portion and the inner peripheral side portion of the annular plate 12 simultaneously contact both the contact surface 10 (fixed side) of the partition wall portion 5 and the end surface 9A (rotating side) of the crankshaft 9, the annular plate 12 is formed. Since it is rotatably provided, the relative speed between each contact surface is distributed to both contact surfaces, and as a result, it is half that in the case of a relative rotation such as a labyrinth seal, which increases safety. To be

[Effect of device]

As described above, according to the present invention, since a material having high heat resistance can be selected and used as the sealing material, there is no thermal problem and there is a possibility of seizure or damage due to contact due to assembly error. Since it is an annular plate made of a small and thin plate material, the space occupied in the axial direction is extremely small, which is advantageous for downsizing and weight saving of the internal combustion engine, and the generated couple can be reduced. In some cases, it is possible to design smartly by the appearance. Further, since a metal plate or a synthetic resin plate can be used as the sealing material, there are various excellent effects such as low cost and advantageous in cost reduction.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a multi-cylinder internal combustion engine to which a sealing device according to the present invention is applied, and FIGS. 2 and 3 are views corresponding to FIG. 1 showing a conventional sealing device. 3, 4 ... Crank case, 5 ... Partition part, 6 ... Crank shaft, 7 ... Crank bearing, 7A ... Outer ring, 7B ...
Inner ring, 8 ... Crank shaft insertion hole, 9 ... Crank shaft,
9A ... End surface, 10 ... Contact surface, 12 ... Annular plate.

Claims (1)

[Scope of utility model registration request] 1. An internal combustion engine having a plurality of cylinders, wherein a crankshaft bearing a crankshaft penetrating a partition wall between adjacent crankcases is supported by a crank bearing so that one side surface of an outer ring of the crank bearing is opposed to the other. The annular plate is provided so as to be movable in a small range in the axial direction, and when the annular plate moves in one direction, one surface of the annular plate can be brought into close contact with at least one side of the outer ring of the crank bearing, while the other surface moves when the other direction moves. An inter-cylinder seal device for an internal combustion engine, characterized in that it is in close contact with at least one of the shaft end surface and the partition wall contact surface.