JPH0212347Y2 - - Google Patents

Description

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

(Prior art) Conventionally, as seen in Japanese Patent Application Laid-Open No. 51-46607, a multi-cylinder engine has a balance weight in order to cancel vibrations caused by secondary reciprocating inertia force generated in the vertical direction. A technique is known in which a balancer shaft is provided and the balancer shaft is driven by a crankshaft at twice the engine speed.

Therefore, in order to support the balancer shaft on the cylinder block, it is necessary to provide a thrust member to restrict the movement of the balancer shaft in the axial direction. This thrust member is generally attached directly to the front wall of the cylinder block with a fixing screw or the like.

However, in the case of the above structure, the fixing screws for attaching the thrust member are screwed into the front wall of the cylinder block, so this front wall needs to be quite thick, and the conventional front wall of the cylinder block is However, when the front wall of the cylinder block is thinned in order to reduce the overall length and weight of the engine, the installation of the thrust member poses an obstacle. Furthermore, the installation of a structure for lubricating the drive mechanism of the balancer shaft is similarly complicated.

(Purpose of the invention) In view of the above circumstances, the present invention aims to shorten the overall length of the engine by arranging the thrust member of the balancer shaft so as not to impede the thinning of the front wall of the cylinder block, and by providing a lubrication structure for the drive mechanism. It is an object of the present invention to provide an engine balancer device as described above.

(Structure of the invention) In the balancer device of the invention, the cylinder block is provided with a boss portion projecting from the front wall, and a thrust member for regulating the axial movement of the balancer shaft extends from the boss portion. A chain sprocket is provided at one end and driven by engagement of a timing chain, while an oil passage opening toward the chain sprocket and timing chain is formed in the boss portion. be.

(Effects of the invention) According to the invention, a boss part that projects forward is provided on the front wall of the cylinder block, and the thrust member is extended to this boss part, so that the fixing screws etc. for fixing the thrust member can be fixed. This does not affect the thickness of the front wall of the cylinder block, and by making the front wall thinner, the overall length of the engine can be shortened and the engine can be made more compact.

In addition, by providing an oil passage in the boss portion that opens toward the chain sprocket and timing chain as the drive mechanism of the balancer shaft, the oil jetted from the oil passage lubricates both, resulting in a simple structure. This makes it possible to prevent wear.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.
Fig. 1 is a schematic front view of the engine, Fig. 2 is a cross-sectional front view of the cylinder block section taken in a direction perpendicular to the crankshaft, and Fig. 3 is a schematic front view of the engine.
FIG. 3 is a cross-sectional view of the bearing portion in the front part of the engine along a line.

In the engine 1, a cylinder head 3 is fastened onto a cylinder block 2, an oil pan 4 is mounted on the lower part of the cylinder block 2, and a head cover 5 is mounted on the cylinder head 3, respectively. A piston 6 is fitted into the cylinder bore 2a of the cylinder block 2, and the piston 6 is connected to a crankshaft 8 by a connecting rod 7.

One end of the crankshaft 8 protrudes to the front side of the cylinder block 2, and a crank pulley 11 is integrally fixed to the crankshaft 8 and is engaged with a timing belt 10 for driving a camshaft 9 of a valve mechanism. There is. The timing belt 10 includes a cam pulley 12 fixed to the camshaft 9 and two idler pulleys 13, 1.
3 to drive this camshaft 9, and a part thereof is engaged to the intermediate pulley 15 of the intermediate shaft 14, so that the intermediate shaft 14 is driven at the same time.

Further, a pair of balancer shafts 17 and 18 are supported on the left and right sides of the cylinder block 2, and a balancer device is disposed therein. These left and right balancer shafts 17, 18 are equipped with eccentrically formed balance weights 17a, 18a, and are housed in balancer cases 19, 19 that are integrally formed on the outer wall 2b of the cylinder block 2 (see Fig. 2). ).
The front end portions of the balancer shafts 17, 18 protrude toward the front side of the cylinder block 2, and chain sprockets 20, 21 are provided at these portions, respectively. On the other hand, the intermediate shaft 14 is provided with an intermediate sprocket 22 on the inside of the intermediate pulley 15, that is, on the cylinder block 2 side. and,
From the intermediate sprocket 22 of the intermediate shaft 14 to the sprockets 2 of the left and right balancer shafts 17 and 18.
A timing chain 24 is engaged with the idler sprocket 23 and the idler sprocket 23.

This timing chain 24 is guided by chain guides 25 and 26, and is connected to the left balancer shaft 17.
The outer side engages with the sprocket 20 of the right balancer shaft 18, and the sprocket 21 of the right balancer shaft 18
The left and right balancer shafts 17, 18 are configured to rotate in opposite directions by engaging the inner sides thereof. The balancer shafts 17 and 18 are driven to rotate at twice the speed of the crankshaft 8, and as shown in FIG. 2, when the piston 6 is at the top dead center or the bottom dead center, the balance weight 17a and 18a are provided eccentrically below the oil pan 4 side.

For the above balancer shafts 17 and 18,
A thrust member 28 that restricts its axial movement;
29 are respectively arranged on the front side of the cylinder block 2. That is, as shown in Figure 3,
The journal portions 17b, 18b at the front ends of the balancer shafts 17, 18 are connected to the cylinder block front wall 2c.
The chain sprockets 20, 21 and the collars 30, 30 are fitted into the shaft ends protruding from the front side, and the tightening bolts 3
It is fixed by fastenings 1 and 31.

The front wall 2c of the cylinder block 2 in the vicinity of the chain sprockets 20, 21 of the balancer shafts 17, 18 is provided with two boss portions 32, 32 each projecting forward. The mounting portions 28a, 29a of the thrust members 28, 29 are brought into contact with each other, and the fixing screws 33, 33
The thrust members 28, 29 are attached by tightening to the boss portions 32, 32.

The thrust members 28, 29 have thrust plates 28b, 29b extending in the direction of the chain sprockets 20, 21, with their tip ends connected to collars 30, 30 fixed to the balancer shafts 17, 18.
is engaged with and fixed in the recess of the balancer shaft 1.
7 and 18 in the axial direction.

Further, the intermediate shaft 14 is supported by a bracket 35, the intermediate sprocket 22 and the intermediate pulley 15 are fixed to the tip by tightening bolts 36, and the timing chain 24 is engaged with each of the sprockets 20 to 23. Ru. A boss portion 32 is protruded from the front wall 2c of the cylinder block at a position that does not interfere with the timing chain 24, and thrust members 28 and 29 of a predetermined shape are provided.

Furthermore, as shown by the chain line in FIG. 3, an oil passage 38 is provided from the cylinder block 2 side to the boss portion 32 for fixing the thrust member 28, and an attachment portion 28a between the boss portion 32 and the thrust member 28 is provided.
The oil passage 3 is connected to the chain sprocket 20 and the timing chain 24 on the contact surface thereof.
Open 8. The balancer shaft 1 is then
The chain sprockets 20, 21 and the timing chain 24, which serve as the drive mechanism of the gears 7 and 18, are lubricated to prevent wear of the drive mechanism with a simple structure. Also, covering the timing chain 24 and sprockets 20 to 23,
Chain cover 3 to prevent oil from scattering
9 is provided.

According to the embodiment described above, the dead space on the front side of the front wall 2c of the cylinder block 2 is utilized, and the balancer shafts 17, 1 are installed in this area.
a thrust member 28 that restricts the axial movement of 8;
By providing the boss parts 32, 32 for fixing the thrust members 28, 29, the fixing screws 33, 33 when attaching the thrust members 28, 29 can be secured to the cylinder block 2.
The front wall 2c does not penetrate into the front wall 2c, and the thickness of the front wall 2c itself can be made thin, thereby shortening the overall length of the engine. Furthermore, by providing the oil passage 38 in the boss portion 32 to lubricate the drive mechanism of the balancer shafts 17 and 18, the lubrication structure is simplified and there is no need to provide a separate oil nozzle. Note that the thrust members 28 and 29 may be formed into a simple plate shape and fixed to the boss portion.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view of an engine equipped with a balancer device according to an embodiment of the present invention, FIG. 2 is a cross-sectional front view of a cylinder block section taken in a direction perpendicular to the crankshaft, and FIG. 3 is a view similar to that shown in FIG. of-
FIG. 3 is a cross-sectional view of the main part of the front part of the engine taken along the line. 1...Engine, 2...Cylinder block, 2
c...Front wall, 8...Crankshaft, 10...
Timing belt, 14... Intermediate shaft, 17, 18
... Balancer shaft, 17a, 18a ... Balance weight, 20, 21 ... Chain sprocket, 24 ... Timing chain, 28, 29
...Thrust member, 28a, 29a...Mounting part,
28b, 29b... Thrust plate, 30...
Collar, 32...Boss part, 33...Fixing screw.

Claims (1)

[Scope of utility model registration request] A balancer shaft having a balance weight is supported on the cylinder block, and a chain sprocket is provided at one end of the balancer shaft,
In an engine balancer device in which the balancer shaft is driven in conjunction with a crankshaft by engaging a timing chain with the chain sprocket at the front face of the cylinder block, the balancer shaft is provided with a boss portion projecting from the front wall of the cylinder block. A thrust member for regulating the axial movement of the balancer shaft extends from the boss portion, and an oil passage opening toward the chain sprocket and timing chain is formed in the boss portion. A characteristic engine balancer device.