JP2519475B2 - V type DOHC engine valve operating system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a V type double overhead cam (abbreviated as DOH).
C) An engine, in particular, a valve operating system for a swing arm type V-DOHC engine equipped with a hydraulic crash adjuster (HLA for short) type end pivot.

(Prior Art) As one type of DOHC engine having two camshafts for intake and exhaust on the upper part of a cylinder head, a V-shaped intake / exhaust valve via a swing arm supported by an HLA type end pivot. Conventionally, a valve mechanism that drives a valve is known.

This end pivot has a high-pressure chamber formed at the bottom of the casing by fitting a pivot rod having a spherical head that supports a swing arm into the casing of a bottomed cylindrical body. By pushing up the pivot rod to the swing arm side, it has a function of replenishing and supplying oil to the high-pressure chamber through the check valve to always keep the valve gap at zero, that is, a function as HLA.

By the way, in a valve mechanism in which a swing arm type rocker arm is rocked by a cam using such an HLA type end pivot as a fulcrum, the lever ratio with the end pivot as a fulcrum changes as the cam rotates. If the direction of rotation of the cam is not appropriate,
There is a problem that the torque ratio in the early stage of valve opening increases toward the HLA side and a large pressing force acts on the HLA, causing the HLA to sink. In particular, when adopting such an HLA type swing arm type valve operating mechanism in a so-called V type DOHC engine having an intake cam shaft and an exhaust cam shaft above each cylinder head of the left and right banks arranged in a V type, Since the cam rotation directions must be adjusted appropriately for each of the four left and right cam shafts, there are major restrictions on the cam drive system and the HLA layout. In addition, in order to reduce the number of parts of the V-type engine, there is also a demand to make the cylinder heads of the left and right banks common, and in order to make the cylinder heads common,
Further restrictions will be added due to the layout of the camshaft and HLA. Moreover, as a matter of course, the cam drive mechanism is required to have a simple and compact structure.

The problem peculiar to the swing arm type V-DOHC engine, which is to eliminate the sinking of the HLA and to make the left and right cylinder heads common, could not be solved by the conventional technology. For example, Japanese Patent Application Laid-Open No. 61-145306 discloses a V-type DOHC engine in which a valve is directly opened and closed via a bucket type tappet, and a pair of intake camshafts and exhaust camshafts for each of the left and right banks are provided. The gears are drive-coupled so that they rotate in opposite directions to each other, and the intake and exhaust camshafts in the left and right banks are made into common parts by providing a predetermined phase difference between the intake and exhaust camshafts. Although a cylinder head that can be used in common is described, such a cylinder head can be used in a bucket type V-type DOHC engine for common use. It can be applied to HLA type swing arm type V DOHC engine, which has a special problem such as HLA sinking. There.

(Object of the Invention) The present invention has been made in view of the above problems in a valve operating device of a swing arm type V DOHC engine equipped with an HLA type end pivot, and prevents the sinking of HLA. Moreover, it is an object of the present invention to obtain a valve operating device that can share a cylinder head.

(Structure of the Invention) According to the present invention, the intake camshaft and the exhaust camshaft of each bank of the V-type DOHC engine are reversely rotated, and the intake camshafts of the left and right banks or the exhaust camshafts are reversely rotated. By adopting such a simple and compact cam drive mechanism and arranging the HLA so that the point of action of the cam on the swing arm slides in the direction from the valve shaft side to the end pivot, the cylinder head is standardized. However, it is intended to prevent the sinking of HLA, and its constitution is as follows. That is, the V type DOHC engine according to the present invention is a swing arm type V type DOHC engine valve operating device equipped with an HLA type end pivot, and the intake camshafts of each bank are arranged symmetrically with respect to the center of the V bank. And an exhaust camshaft are drive-coupled with each other by a pair of gears so as to rotate in opposite directions to each other, and the intake camshaft of one bank and the exhaust camshaft of the other bank are rotationally driven in the same direction by a crankshaft. The end pivot is arranged on the leading side in the cam rotation direction.

(Operation) The intake camshaft of one bank and the exhaust camshaft of the other bank are rotationally driven in the same direction by the crankshaft. The exhaust camshaft of the one bank is rotationally driven in the opposite direction to the intake camshaft of the same bank via a pair of gears, and the intake camshaft of the other bank is driven via another pair of gears. It is driven to rotate in the direction opposite to the exhaust camshaft of the bank. That is,
The intake camshafts of the left and right banks or the exhaust camshafts of the left and right banks rotate in reverse.

The intake camshafts and the exhaust camshafts are symmetrically arranged with the center of the V bank as a boundary, and in addition, as described above, the rotations of the intake camshafts are opposite to each other. Also V
The banks are symmetrical with respect to the center, and the positions of the end pivots on the leading side of the exhaust cam rotation direction of both banks are also symmetrical. Further, since the intake / exhaust camshafts in the same bank rotate in opposite directions, the position of the end pivot in each bank is opposite to the intake camshaft and the exhaust camshaft. Therefore, the cylinder heads of the left and right banks can be shaped so that they can be used by reversing each other axially forward and backward.

In addition, each end pivot is arranged on the leading side in the cam rotation direction, and the point of action of the cam on each swing arm slides in the direction from the valve shaft side to the end pivot. It is large on the side and therefore the pressing force acting on the HLA is relatively small.

(Example) Hereinafter, the Example of this invention is described based on drawing.

FIG. 1 shows a first embodiment of the present invention. As shown in the figure, the intake camshafts 101, 102 and the exhaust camshafts 103, 104 of the left and right banks of this V-type DOHC engine are located at symmetrical positions with respect to the center of the V bank.
The intake camshafts 101, 102 are arranged inside the V bank, and the exhaust camshafts 103, 104 are arranged outside.
Further, the intake valve 105 and the exhaust valve 106 of the left bank, and the intake valve 107 and the exhaust valve 108 of the right bank are respectively provided in a V shape, and each valve 10
HLAs (end pivots) 113, 114, 115, and 116 supporting the swing arms 109, 110, 111, and 112 of the 5, 106, 107, and 108 are provided inside the V-shaped valve array in each bank and in parallel with each valve shaft.

Left bank intake camshaft 101 and exhaust camshaft 1
03 is drivingly connected by a pair of gears 117, 118, and
Both camshafts 102, 104 of the right bank are also drivingly connected by another pair of gears 119, 120. Further, timing pulleys 121 and 122 are respectively fixed to the intake camshaft 101 of the left bank and the exhaust camshaft 104 of the right bank, and a timing belt 126 is provided via idlers 124 and 125 so as to wind the crankshaft pulley 123 and both timing pulleys 121 and 122. It is installed. By such belt drive and gear coupling, each camshaft 10
1 to 104 rotate in the direction of the arrow in FIG. That is, in the left bank, the intake camshaft 101 rotates right and the intake camshaft 103 rotates left, and in the right bank, the intake camshaft 102 rotates left and the exhaust camshaft 104 rotates right. Each camshaft 101-104 rotates in this way,
Further, since the HLA is arranged as described above, the cam surface of each of the cams first acts on the swing arms 109 to 112 at a position close to the valve shaft, and the end pivot 11 moves with the rotation.
The point of action slides to the 3 to 116 side. Therefore, the torque ratio on the HLA side at the initial stage of valve opening is small, and a large force that causes the sinking of HLA does not act. Further, the camshafts 101-104, intake / exhaust valves 105-108, HLA113-116, etc. are all symmetrically arranged with the center of the V bank as a boundary, and the cylinder heads of the left and right banks are common to be mounted in an inverted manner. Has been converted. By configuring the valve gear in this way, the front side of the engine can be lowered, and the first
There is also a mounting advantage that the hood line can be placed along the phantom line shown in the figure.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment also, the left and right banks of the intake camshafts
The 201, 202 and the exhaust camshafts 203, 204 are arranged symmetrically as in the first embodiment, and the intake valve 205 and the exhaust valve 206 of the left bank and the intake valve 207 and the exhaust valve 208 of the right bank are also arranged in a V shape. There is. However, in the case of this embodiment, the HLAs 213, 214, 21 supporting the respective swing arms 209, 210, 211, 212.
5,216 are provided on both outer sides of the V-shaped valve array in the left and right banks. The left bank intake camshaft 201 and the exhaust camshaft 203 are drivingly connected by a pair of gears 217 and 218, and the right bank intake camshaft 202 and the exhaust camshaft 204 are drivingly connected by another pair of gears 219 and 220. This is the same as the case of the above embodiment. However, in this embodiment, the timing pulleys 221 and 222 are provided on the exhaust cam shaft 203 of the left bank and the intake cam shaft 202 of the right bank. A timing belt 226 is attached via idlers 224 and 225 so as to wind the timing pulleys 221 and 222 around the crankshaft pulley 223.

The rotation directions of the camshafts 201 to 204 are as shown by arrows in FIG. That is, in the left bank, the intake camshaft 201 rotates left and the exhaust camshaft 203 rotates right, and in the right bank, the intake camshaft 202 rotates right and the exhaust camshaft 204 rotates left. Due to the rotation of each camshaft and the positional relationship of HLA as described above, the torque ratio on the HLA side at the initial stage of valve opening is small in this embodiment as well. Further, the camshafts 201 to 204, intake / exhaust valves 205 to 208, HLAs 213 to 216, etc. are also symmetrically arranged with the center of the V bank as a boundary. Therefore, also in this embodiment, the left and right cylinder heads can be made common, and the sinking of HLA can be prevented. Similar to the previous embodiment, the front side of the engine (the direction opposite to that shown in FIG. 1 in the description of FIG. 2) can be lowered and the engine can be placed along the bonnet line.

EFFECTS OF THE INVENTION Since the present invention is configured as described above, a swing arm type V-type DO equipped with an HLA type end pivot is provided.
HC engine has a simple and compact structure
It is possible to prevent the sinking of HLA and to make the cylinder head common.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention, and FIG. 2 is a schematic diagram showing a second embodiment of the present invention. 101,102,201,202: Intake camshaft, 103,104,203,204:
Exhaust camshaft, 105,107,205,207: intake valve, 106,108,
206,208: Exhaust valve, 109,110,111,112,209,210,211,212: Swing arm, 113,114,115,116,213,214,215,216: HL
A, 117,118,119,120,217,218,219,220: Gear, 121,122,2
21,222: Timing pulley.

Claims (1)

(57) [Claims] 1. A valve operating system for a swing arm type V DOHC engine equipped with an HLA type end pivot, comprising:
The intake camshaft and exhaust camshaft of each bank symmetrically arranged with the center of the bank as a boundary are drive-coupled by a pair of gears so as to rotate in opposite directions to each other, and the intake camshaft of one bank and the exhaust gas of the other bank are connected. A valve operating system for a V-type DOHC engine characterized in that a camshaft is rotationally driven in the same direction by a crankshaft, and each end pivot is arranged on the leading side in the cam rotation direction.