JPH0532679Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement of a balancer device that reduces engine vibration.

(Prior Art) Generally, in order to reduce engine vibration, a multi-cylinder engine is equipped with a balancer device that generates vibrations in the opposite direction to engine vibrations to offset each other's vibrations.

As an example of the above-mentioned engine balancer device, as exemplified in Japanese Utility Model Application Publication No. 59-32748,
A balancer shaft extending in the cylinder row direction of the engine, an unbalanced portion provided on one side of the balancer shaft in the cylinder row direction and formed offset with respect to the axis, and an unbalanced portion extending on the other side of the balancer shaft in the cylinder row direction. A drive pulley is known that is provided with a drive pulley that transmits the rotational force of the crankshaft to the balancer shaft.

This engine balancer device rotates the unbalanced part in synchronization with the rotation of the crankshaft at a rotation speed that is the same as the rotation speed of the crankshaft or an integer multiple of two or more, thereby reducing the amount of energy generated by the reciprocating motion of each piston. This is intended to offset the vibrations of the engine caused by the rotation of the unbalanced part by the vibrations in the opposite direction that occur in the balancer shaft.

(Problem to be solved by the invention) However, in the engine balancer device as described above, since the unbalanced part and the drive pulley are integrally provided via the balancer shaft body, twisting of the crankshaft may occur. Vibration is transmitted to the drive pulley via a timing belt or the like, and this torsional vibration is directly transmitted to the unbalanced portion. For this reason, there is a problem in that the bearing part provided in the unbalanced part for pivotally supporting the balancer shaft body is subjected to large repeated loads and seizes up.

Additionally, if there is a manufacturing error in the unbalanced part, self-excited vibration will occur, causing the axis of the unbalanced part to swing.
This self-excited vibration is transmitted as vibration to the drive pulley via the balancer shaft body. For this reason, a problem arises in that a bearing provided on the balancer shaft body for pivotally supporting the drive pulley is subjected to repeated loads and seizes up.

The present invention solves the above problems at once, and uses a compact structure to reduce the torsional vibration of the balancer shaft body transmitted from the drive pulley and the vibration of the balancer shaft body due to self-excited vibration of the unbalanced part. The purpose is to reduce repetitive loads acting on the bearing of the unbalanced portion and the bearing of the drive pulley.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a dynamic damper between the unbalanced part and the drive pulley, so that the damper is not transmitted to the balancer shaft body via the drive pulley. By absorbing both the torsional vibration and the vibration of the balancer shaft body due to the self-excited vibration of the unbalanced part using a dynamic damper, the torsional vibration is transmitted from the drive pulley to the unbalanced part and the vibration of the balancer shaft body is balanced. This also prevents transmission from the shaft body to the drive pulley.

Specifically, the solution taken by the present invention includes an engine balancer device that includes a balancer shaft body provided to extend in the cylinder row direction of the engine, and a shaft provided on one side of the balancer shaft body in the cylinder row direction. an unbalanced part formed to be offset with respect to the center; a bearing part provided in the unbalanced part for pivotally supporting the balancer shaft body; and a crank provided on the other side of the balancer shaft body in the cylinder row direction. a drive pulley that transmits the rotational force of the shaft to the balancer shaft body via an endless rotational force transmission member; a bearing portion provided on the other side of the balancer shaft body in the cylinder row direction and for pivotally supporting the drive pulley; and a dynamic damper provided in a portion of the balance section of the balancer shaft body between the drive pulley and the unbalance section and located within the cylinder block of the engine.

(Function) With the above configuration, the torsional vibration transmitted from the crankshaft to the drive pulley via the endless rotational force transmission member is transmitted to the balancer shaft body and then absorbed by the dynamic damper, so that the torsional vibration is absorbed by the dynamic damper. Torsional vibration of the pulley is not transmitted to the unbalanced part.

On the other hand, the self-excited vibration generated in the unbalanced part is
After the vibration is transmitted to the balancer shaft body, it is absorbed by the dynamic damper installed in the balance part of the balancer shaft.
The vibration of the balancer shaft body is not transmitted to the drive pulley.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

1 and 2 show an in-line four-cylinder engine equipped with an engine balancer device according to the present invention. In the figure, reference numeral 1 denotes a cylinder block, and the cylinder block 1 has four cylinders 2, 2, . Further, in the crank case 4 of the cylinder block 1, first to third cylinders are arranged in order from the front corresponding to the spaces between the cylinders 2 and 2.
Vertical walls 5, 6, 7 are provided.

A crankshaft 8 as an engine output shaft is attached to the cylinder block 1, and the front and rear walls 4a, 4b of the crankcase 4, the first to third vertical walls 5,
It is supported by metals 9, 9... disposed at 6, 7.

Furthermore, on both sides of the cylinder block 1,
A pair of balancers 10 and 11 are provided, each disposed in parallel with the crankshaft 8, and each balancer 10 and 11 is connected to the front wall 4 of the crankcase 4.
a and the length corresponding to the first vertical wall 5 to the third vertical wall 7.

Front wall 4a to first wall in each balancer 10, 11
In portions corresponding to the spaces between the vertical walls 5, shaft portions 10a and 11a are formed as balancer shaft bodies whose axes coincide with the axes of the balancers 10 and 11, respectively.

In each balancer 10, 11, a portion corresponding to between the first vertical wall 5 and the third vertical wall 7 has a balancer 10,
Unbalanced portions 10b and 11b are formed so as to be offset in the radial direction with respect to each of the axes 11.

Journal portions 12 and 13 as bearing portions are formed at both axial ends and the center portion of each unbalanced portion 10b and 11b and at the front end portion of the balancers 10 and 11, respectively, and the front wall 4a of the cylinder block 1 and first to third vertical walls 5, 6, 7
A metal 14 serving as a bearing member that rotatably supports each of the journal parts 12 and 13 is fitted into the metal member 14 .

Front end of crankshaft 8 and each balancer 1
The rotational driving force of the crankshaft 8 is connected to the front end of the shaft portions 10a and 11a of 0 and 11, respectively, by a balancer 1.
Drive pulley 15,1 for transmission to 0,11
6 and 17 are attached, and the drive pulley 1
A timing belt 18 as an endless rotational force transmitting member is wound around 5, 16, and 17. Each drive pulley 15, 16, 17 is connected to a balancer 10, 1
The balancers 10 and 11 are formed so that they are rotated in opposite directions at a rotation speed twice that of the crankshaft 8.
Vibrations occur in the opposite direction to the vibrations of the crankshaft 8 caused by the reciprocating motion of each piston 3.

Furthermore, the shaft portion 10 of each of the balancers 10 and 11
A dynamic damper 19 is installed on the outer peripheral surface of a and 11a.
is provided. Dynamic damper 19 is
As shown in FIG. 3, a hollow cylindrical mass portion 19a fitted on the outer peripheral surface of each shaft portion 10a, 11a;
Fitted between the mass portion 19a and each shaft portion 10a, 11a, the mass portion 19a is inserted into each shaft portion 10a, 11a.
The rubber part 19b elastically supports the shaft part 19a, and absorbs the torsional vibration energy transmitted to each shaft part 10a, 11a and the vibration energy based on the vibration of the axis of each shaft part 10a, 11a. being done.

In FIG. 1, 20 is a camshaft driven by the crankshaft 8 via the timing belt 18, 21 is an oil passage that supplies engine oil to the crankshaft 8, the balancers 10 and 11, and the metal of the camshaft 20.
22 is a cylinder head, and 23 is an oil pan.

Next, to explain the operation of the above embodiment,
The torsional vibration of the crankshaft 8 is transmitted from its drive pulley 15 via the timing belt 18 to the drive pulleys 16 and 17 on the front side of the shaft portions 10a and 11a of each balancer 10 and 11.
a, 11a, but each shaft portion 10a, 11
The vibration energy of the torsional vibration transmitted to a is absorbed by the dynamic damper 19, so
Torsional vibration of each shaft portion 10a, 11a is not transmitted to unbalanced portions 10b, 11b. As a result, the metal 1 of each unbalanced portion 10b, 11b
Since the bearing load acting on the metals 14 is suppressed to a low level, the reliability of the metals 14 is improved, and the metals 14 can be made smaller to reduce resistance.

Furthermore, when self-excited vibration occurs in which the axes of the balancers 10 and 11 swing due to manufacturing errors in the unbalanced parts 10b and 11b, this self-excited vibration causes each shaft part 1 to vibrate.
0a, 11a, but each shaft portion 10a, 1
Since the vibration energy of the self-excited vibration transmitted to 1a is absorbed by the dynamic damper 19 in the same manner as described above, the self-excited vibration is not transmitted to the drive pulleys 16 and 17 on the front side of each shaft portion 10a and 11a. As a result, the bearing load acting on the metal 14 located immediately after the drive pulleys 16 and 17 can be suppressed to a low level, improving the reliability of the metal 14 and making it possible to reduce the size of the metal 14, thereby increasing the resistance. This can be reduced.

(Effect of the invention) As explained above, according to the engine balancer device according to the invention, since the dynamic damper is provided between the unbalanced part of the balancer shaft body and the drive pulley, the endless rotational force from the crank pulley is The vibration of the balancer shaft body caused by the torsional vibration transmitted to the drive pulley via the transmission member and the self-excited vibration of the unbalanced portion are both reduced by the dynamic damper. For this reason, the torsional vibration of the clamp pulley is transmitted to the unbalanced part and ultimately to the bearing part of the unbalanced part, and the self-excited vibration of the unbalanced part is transmitted as vibration to the drive pulley and ultimately to the drive part that supports the drive pulley. Since this situation can be prevented, it is possible to prevent seizure in the bearing portion of the unbalanced portion and the bearing portion that pivotally supports the drive pulley.

In addition, since the dynamic damper is installed in a part of the balancer section that is located inside the cylinder block of the engine, the dynamic damper can be installed compactly by utilizing the empty space in the cylinder block where there is no unbalanced part. be able to.

Therefore, according to the present invention, it is possible to improve the reliability of the bearing part of the unbalanced part and the bearing part that pivotally supports the drive pulley due to the compact structure.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional side view of the engine, and FIG. 2 is a side view of the engine.
3 is a sectional view taken along the - line in FIG. 2. 8... Crankshaft, 10, 11... Balancer, 10a, 11a... Shaft part (balancer shaft body), 10b, 11b... Unbalanced part,
15-17... Drive pulley, 18... Timing belt (endless rotational force transmission member), 19... Dynamic damper.

Claims (1)

[Scope of utility model registration request] a balancer shaft body provided to extend in the cylinder row direction of the engine; an unbalanced portion provided on one side of the balancer shaft body in the cylinder row direction and formed to be offset with respect to the axis; and the unbalanced portion a bearing provided on the other side of the balancer shaft body in the direction of the cylinder row for transmitting the rotational force of the crankshaft to the balancer shaft body through an endless rotational force transmission member. a driving pulley for transmitting a transmission, a bearing portion provided on the other side in the cylinder row direction of the balancer shaft body for pivotally supporting the driving pulley, and the driving pulley and the unbalanced portion in the balance portion of the balancer shaft body. 1. A balancer device for an engine, comprising: a dynamic damper provided between the cylinder block of the engine and at a portion located within the cylinder block of the engine.