JPS61275507A - Engine cam shaft driving device - Google Patents

Abstract

PURPOSE:To use identical form of suction cam and identical form of exhaust cam on each cam shafts in multiple cylinder rows by constituting such that suction and exhaust cam shafts in each cylinder row rotate in the directions opposite to each other when seen from the direction of crank shaft. CONSTITUTION:A V type engine has two cylinder rows 2 and 3. Both cylinder heads 8 and 9 attached on the top surfaces of respective cylinder rows 2 and 3 are respectively equipped with suction and exhaust cam shafts 10A and 10B, and suction and exhaust cam shafts 11A and 11B respectively symmetrically when seen from the crank shaft direction. In this case, the exhaust cam shaft 10B and the suction cam shaft 11A are rotated in the same direction with and by means of the crank shaft rotation. The rotary force of both cam shafts 10B and 11A is transmitted through gears 21, 22 or 23, 24 to the suction cam shaft 10A and exhaust cam shaft 11B so that both cam shafts 10A and 11B are rotated in the direction opposite to that of the crank shaft 7.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention has two cylinder rows, and intake and exhaust camshafts are arranged symmetrically in the cylinder head of each cylinder row when viewed from the crankshaft axial direction. The so-called double overhead camshaft (DOHC) installed
The present invention relates to a camshaft drive device for a type engine.

(Conventional technology) Traditionally, it has been used as a so-called DOHC type engine.

For example, as described in Japanese Unexamined Patent Publication No. 57-159904, there are two cylinder rows, and intake and exhaust camshafts are arranged symmetrically in the cylinder head of each cylinder row when viewed from the crankshaft axial direction. What has been done is known.

In the engine as described above, a common timing belt is wrapped around the intake and exhaust camshafts in each cylinder row, so both camshafts rotate in the same direction as viewed from the crankshaft axis. Since output is taken directly from the same crankshaft, the intake camshafts and exhaust camshafts are asymmetrical in that their rotation directions are opposite to each other when viewed from the crankshaft axis.

Therefore, in an engine where the intake camshafts and the exhaust camshafts have different rotation directions as described above, for example, when opening and closing the intake and exhaust valves via a rocker arm, the intake camshaft or the exhaust camshaft If a common camshaft is used as the camshaft, the lift characteristics of the intake and exhaust valves driven by the camshaft will be different due to the difference in rotation direction. Shafts cannot be shared.

(Object of the Invention) An object of the present invention is to provide an engine camshaft drive device that can make the cam forms of the intake camshafts and the exhaust camshafts the same in both cylinder rows.

(Structure of the Invention) The present invention has two cylinder rows, and intake and exhaust camshafts are disposed symmetrically in the cylinder head of each cylinder row when viewed from the crankshaft axial direction. This invention relates to an engine camshaft drive device in which the lift characteristics of the intake and exhaust valves that are driven by the engine differ depending on the rotational direction of the camshaft.

The present invention is characterized in that the intake camshafts and the exhaust camshafts are driven to rotate in opposite directions when viewed from the crankshaft axial direction.

(Example) Embodiments of the present invention will be described below based on the drawings.

A DOHC type V-type engine 1 shown in FIGS. 1 and 2 has first and second cylinder rows 2 and 3 arranged left and right in a V-shape. An oil pan 5 is attached to the. A crankshaft 7 is provided in a crankcase 6 made up of the oil pan 5 and the lower part of the cylinder block 4.

Intake camshafts IOA, IIA and exhaust camshafts IOB, IIB are connected to the cylinder heads 8.9 of the first and second cylinder rows 2, 3, which are hermetically sealed to the upper surface of the cylinder block 4, respectively, from the crankshaft axial direction. Two of the four camshafts are installed symmetrically when viewed from the
The actual camshaft 10B, IIA is the crankshaft 7
The camshafts IOB, 1 and IA and the crankshaft 7 can be rotated simultaneously. That is, camshaft IOB,
Timing pulley 12 fixed to the front end of IIA
．． 13 and a crank pulley 14 fixed near the front end of the crankshaft 7. A timing belt 15 is wound around the crank pulley 14. 16.17.18 are idlers.

Further, within the cylinder block 4, the first cylinder row 2 includes odd numbered cylinders I, m, and V, and the second cylinder row 3 includes even numbered cylinders n, rv.

(2) are arranged respectively, and the pistons of each cylinder (2) to (2) are connected to the crankshaft 7 in order from the front side by connecting rods (not shown). Thus, the cylinders of each cylinder row are located between the cylinders of the other cylinder row in the axial direction of the crankshaft 7, and the cylinders of the second cylinder row 3 are located between the cylinders of the second cylinder row 3.

IV and Vl are cylinders I and III of the first cylinder row 2
.

It is arranged so as to be shifted in the axial direction of the crankshaft 7 so as to be further away from the timing pulleys 12 and 13 than in (2).

In the second cylinder row 3, the intake camshaft 11A
A gear 21 is attached between the timing pulley 13 and a bearing (not shown) closest to it, and another gear 22 that meshes with the gear 21 is attached to the front end of the exhaust camshaft IIB. As a result, the exhaust camshaft IIB is rotationally driven via the intake camshaft IIA.

On the other hand, in the first cylinder row 2, the second cylinder row 3
Gears 23 and 24 that mesh with each other are fixed to the ends of the camshafts IOA and 10B on the opposite side, so that the intake camshaft IOA is rotationally driven via the exhaust camshaft IOB.

In this way, the gears 21, 22 and 23°24 are
This occurs inevitably in a DOHC V-type engine.
The gears 21, 22 and 23, 24 are arranged by effectively utilizing the space where no cylinders are arranged, that is, the space behind the first cylinder row 2 and in front of the second cylinder row 3, so that the gears 21, 22 and 23, 24 are arranged in the gear cover 41. It is covered by 42.

Further, head covers 25 and 26 are provided on the upper surfaces of the cylinder heads 8 and 9 of the first and second cylinder rows 2 and 3, respectively, and a position corresponding to the upper part of the exhaust camshaft IIB inside one of the head covers 26 is provided. An oil separator 27 is formed therein.

28 is a distributor, its rotating shaft (not shown)
A worm wheel 30 is fixed to the lower end of the worm gear 3 fixed to the end of the exhaust camshaft IIB in the second cylinder row 3.
It meshes with 1.

This worm wheel 30 is connected to the exhaust camshaft lI.
It meshes with the worm gear 31 at a portion outside the axis of B. As a result, the distributor 28 is driven by the rotation of the camshaft 11B. Although not shown, the distributor 28 is provided with a worm wheel 30. which is separate from the head cover 26. It is attached to a cover that covers the worm gear 31 and the like.

Note that an air intake device 34 is interposed between the cylinder rows 2 and 3, which supplies air sucked from an air cleaner (not shown) from a surge tank 32 to each cylinder via a plurality of intake pipes 33. . Correspondingly, in each cylinder row 2.3, the intake camshafts IOA and IIA are installed inwardly.
However, exhaust camshafts IOB and IIB are provided on the outer side.

With the above configuration, the rotational drive of the crankshaft 7 rotates the exhaust camshaft IOB of the first cylinder row 2 and the intake camshaft IIA of the second cylinder row 3 in the same direction. Therefore, the rotational driving force of both the camshafts IOB and IIA is transmitted to the intake camshaft IOA of the first cylinder row 2 and the exhaust camshaft of the second cylinder row 3 via the gears 21, 22 or 23, 24. IIB, both camshafts I
OA, IIB are crankshaft 7 (camshaft IO
B, IIA) will rotate in the opposite direction.

Therefore, between the intake camshafts IOA and 11A,
The exhaust camshafts IOB and IIB are driven to rotate in opposite directions when viewed from the axial direction of the crankshaft 7, thereby driving predetermined intake and exhaust valves.

In the above embodiment, the present invention is applied to a V-type engine, but it can also be applied to a horizontally opposed engine, and although only one timing belt is used, the intake camshaft , if the exhaust camshafts are configured to rotate in opposite directions when viewed from the crankshaft axis direction, the timing belt is
The structure of a book is also acceptable.

(Effects of the Invention) Since the present invention is configured as described above, in both cylinder rows, the intake camshafts and the exhaust camshafts rotate in opposite directions when viewed from the crankshaft axial direction, so that the intake camshafts rotate in opposite directions when viewed from the crankshaft axial direction. It is possible to make the cam forms of the shafts and the exhaust camshafts the same.

[Brief explanation of drawings]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a front view of a DOHC type V-type engine, and FIG. 2 is a partially sectional plan view of the same. 1... V-type engine, 2, 3... Cylinder row, 8°9... Cylinder head, IOA,
IIA・・・Intake camshaft, IOB, II
B...Exhaust camshaft.

Claims (1)

[Claims] (1) It has two cylinder rows, intake and exhaust camshafts are arranged symmetrically in the cylinder head of each cylinder row when viewed from the crankshaft axial direction, and the intake and exhaust are driven by the respective camshafts. In an engine camshaft drive device in which the lift characteristics of the valves differ depending on the direction of rotation of the camshaft, the intake camshafts and the exhaust camshafts are driven to rotate in opposite directions when viewed from the crankshaft axis direction. An engine camshaft drive device featuring: