JPH0350271Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an idle gear holding structure that connects a timing gear attached to a crankshaft and a driven gear attached to a camshaft.

(Prior art) For OHC and DOHC type engines,
In order to synchronize the rotation of the crankshaft with the opening and closing of the valves, a timing gear connected to the crankshaft and a driven gear connected to the camshaft are connected via an idle gear.

Here, since the idle gear is attached to the cylinder head side and the timing gear is attached to the crankcase side, the backlash between the timing gear and the idle gear that meshes with it is too large due to manufacturing and assembly errors. or too small. If the amount of backlash is not appropriate, the noise will increase and the life of the gear will be shortened, so the amount of backlash must be adjusted.

For this reason, a holding structure as shown in FIG. 3 has conventionally been adopted.

That is, the idle gear 102 meshes with the timing gear 101 connected to the crankshaft 100.
The idle gear 102 and the idle gear 103 that meshes with a driven gear (not shown) are held in a holder 10 consisting of two plates 104a, 104a.
4, and the flange portion of this holder 104 is fixed to the cylinder head 107 with a bolt 106 via a shim 105.
Then, timing gear 101 and idle gear 1
In order to adjust the backlash of 02, the position of the idle gear 102 is changed by replacing the shim 105 interposed between the holder 104 and the cylinder head 107.

(Problem to be solved by the invention) As mentioned above, in the past, in order to adjust the bump between the timing gear attached to the crankshaft and the idle gear that meshes with the timing gear, the holder's flange This is done by replacing the shim that is inserted between the part and the cylinder head.

As a result, the thickness can only be adjusted by the change in shim thickness, making it impossible to make fine adjustments.
There is also a problem in that the time and effort required to replace the shims is troublesome.

(Means for Solving the Problems) In order to solve the above problems, the present invention does not fix the holder that holds the idle gear directly to the cylinder head, but instead connects the first holder that holds the idle gear to the second holder. The first holder is attached to the cylinder head via the first holder, and the position of the first holder can be adjusted relative to the second holder.

(Example) An example of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a front sectional view of an engine to which the gear train holding structure according to the present invention is applied, and FIG. 2 is a sectional view taken along the line A-A in FIG. 2. It is composed of a cylinder head 3 and a cylinder head cover 4, and a gasket 5 is interposed between these members.

A crankshaft 6 is rotatably supported within the crankcase 1, and a timing gear 7 is fitted onto the crankshaft 6. Further, a camshaft 8 is installed in the space formed by the cylinder head 3 and the cylinder head cover 4, and a driven gear 9 is fitted into the camshaft 8.
are connected by idle gears 10 and 11.

The idle gears 10 and 11 are attached to the first holder 12
is held in This first holder 12 is made by butting plate bodies 12a, 12a, and these plate bodies 1
The shafts 10 of the idle gears 10 and 11 are attached to 2a and 12a.
a, 11a, and these shafts 10a, 11
Idle gears 10 and 11 are rotatably supported by ball bearings 13 and 14 at a.

Both sides of the first holder 12 are fixed to the cylinder block 2 by bolts 15 inserted into long holes 2a formed in the cylinder head 2, and the upper end is attached to the cylinder head 3 via the second holder 16. Supported.

That is, the second holder 16 has a flange portion 16a.
A flange portion 16a is fixed to the cylinder head 3 with bolts 17. The upper end of the first holder 12 faces into the recess 16b, and is held by the second holder 16 with bolts 18 and 19. Here, the bolt 18 is attached to the second holder 16
Screw into the female screw hole 20 formed in the upper wall, and insert the bolt 1.
9 is inserted into a long hole 21 formed in the side wall of the holder 16. Therefore, the bolt 15 and the bolt 19
are inserted into long holes 2a and 21 formed in the cylinder block 2 or the second holder 16, so if the bolt 18 is turned with the bolts 15 and 19 loosened, the first holder 12 moves up and down. The backlash of the timing gear 7 with the idle gear 10 is adjusted. After adjusting the position to achieve a predetermined backlash, bolts 15 and 19 are tightened to fix the first holder 12 to the cylinder block 2 and cylinder head 3.

(Effect of the invention) As explained above, according to the invention, the bolt 1
The idle gear connecting the timing gear fitted to the camshaft 7 and the driven gear fitted to the camshaft is held by a first holder, and this first holder is attached to a second holder so that its position can be adjusted. Since the holder is fixed to the cylinder head, there is no need to adjust the backlash between the timing gear and the idle gear by replacing shims as in the conventional case.
The buckle rush can be adjusted by simply changing the mounting position on the holder by turning a bolt or the like, and furthermore, the buckle buckle can be easily finely adjusted.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view of an engine to which the gear train holding structure according to the present invention is applied, Fig. 2 is a sectional view taken along the line A-A in Fig. 1, and Fig. 3 is Fig. 2 showing a conventional holding structure. It is a similar cross-sectional view. In the drawing, 1 is a crankshaft, 2 is a cylinder block, 2a and 21 are long holes, 3 is a cylinder head, 4 is a cylinder head cover, 6 is a crankshaft, 7 is a timing gear, 8 is a camshaft, 9 is a driven gear, 10 and 11 are idle gears, 12 is a first holder, 15, 18, and 19 are bolts, and 16 is a second holder.

Claims (1)

[Scope of utility model registration request] In a gear train for driving a camshaft, a timing gear connected to a crankshaft and a driven gear connected to a camshaft are connected via a plurality of idle gears, and the rotation of the timing gear is transmitted to the driven gear. It is rotatably held in the holder of 1,
A holding structure for a gear train for driving a camshaft, characterized in that the first holder is attached to a second holder fixed to a cylinder head so that the position thereof can be adjusted.