JPH0640888Y2 - Valve mechanism of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of Invention] <Industrial Application Field> The present invention is to selectively connect or release a plurality of adjacent rocker arms by the action of hydraulic pressure according to the rotation speed of an internal combustion engine. The present invention relates to a valve operating mechanism of an internal combustion engine provided with rocker arm connection switching means for switching the number of operating valves of intake valves or exhaust valves and varying the operation timing of the valves.

<Prior Art> Conventionally, for example, in Japanese Patent Laid-Open No. 61-19911, a pair of low-speed cams and a single high-speed cam are integrally formed on a cam shaft that is rotationally driven in synchronization with the rotation of an engine. And a pair of direct acting rocker arms slidingly contacting the low speed cam and engaging a pair of intake valves or exhaust valves and a floating rocker arm slidingly contacting the high speed cam are pivotally mounted on the rocker shaft for relative angular displacement. There has been proposed a valve operating mechanism for an internal combustion engine in which each rocker arm is integrally or separately rocked by a connection switching means depending on the rotation speed of the engine. The connection switching means is built in the rocker arm for each cylinder, and is operated by the hydraulic pressure supplied from the oil pump driven by the engine using a part of the engine lubricating oil.

In order to supply hydraulic pressure to the connection switching means, the rocker shaft is made hollow to form an oil supply passage therein, and the connection switching means is connected through a passage provided in the rocker arm from an oil supply hole formed in the rocker shaft pipe wall. It communicates with the hydraulic chamber. Therefore, it is necessary to position the rocker shaft in both the axial direction and the rotation direction and fix the rocker shaft to the cylinder head so that the oil supply hole of the rocker shaft and the passage inlet of the rocker arm coincide with each other.

On the other hand, for example, in Japanese Patent Application No. 61-314802, low-speed lubricating oil passage for lubricating the sliding contact surfaces of low-speed cam and rocker arm and high-speed lubricating for lubricating high-speed cam and rocker arm sliding contact surface. Disclosed is a valve mechanism for an internal combustion engine in which an oil passage is provided separately and independently, and a high speed lubricating oil passage is connected to a rear end of an oil supply passage of a connection switching means provided inside a rocker shaft via a throttle. As a result, the operation of the connection switching means can be made smooth and reliable, the cam can be sufficiently lubricated during high-speed operation, and the structure of the oil supply system can be simplified.

Generally, the rocker shaft is positioned and fixed to the cylinder head by bolts, knock pins, or the like. Further, the connection structure of the connection switching means from the oil supply passage to the high-speed lubricating oil passage can be configured separately from the rocker shaft positioning structure. However, if each of them is made into a separate structure, the number of parts increases, the number of processing / assembly processes increases, the manufacturing cost increases, and the structure becomes more complicated and large.

<Problems to be Solved by the Invention> Therefore, an object of the present invention is to share a rocker shaft positioning structure and a connection structure from an oil supply passage inside the rocker shaft to an oil supply system for lubricating a cam etc. An object of the present invention is to provide a valve operating mechanism for an internal combustion engine, which is capable of reducing the manufacturing cost by reducing the number of points and the number of working / assembling steps and achieving a compact layout.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, the above-mentioned object is swayed by a cam on a cam shaft pivotably supported by a rocker shaft and rotating in synchronization with a crank shaft. Multiple rocker arms that are driven dynamically,
Rocker arm connection switching means for selectively connecting or disconnecting adjacent rocker arms by the action of hydraulic pressure; a hydraulic oil supply passage provided inside the rocker shaft for supplying hydraulic pressure to the rocker arm connection switching means; Lubrication for lubricating the oil supply passage provided inside the cam holder supporting the cam shaft and connected to the rear end of the hydraulic oil supply passage through the throttle, and the cam connected to the oil supply passage in the cam holder. A valve operating mechanism of an internal combustion engine, comprising: an oil supply passage for use; a throttle member that defines the throttle is penetrated from a cylinder head side in a direction orthogonal to a pipe wall of the rocker shaft, and is inserted into a recess of the cam holder. By providing the valve mechanism of the internal combustion engine, the rocker shaft and the cam holder are positioned. It is.

<Operation> With this configuration, the rocker shaft and the cam holder are positioned on the cylinder head by the throttle member, and at the same time, the lubrication oil supply passage for the cam is connected to the rear end of the hydraulic oil supply passage inside the rocker shaft through the throttle. You can

<Embodiment> Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, a DOHC type multi-cylinder engine to which the present invention is applied is provided with two intake valves 2 and 3 and exhaust valves 4 and 5 in each cylinder 1, and at the upper end of the cylinder block of the engine. Inside the coupled cylinder head 6, a valve mechanism 7 on the intake side and a valve mechanism 8 on the exhaust side are arranged in parallel and symmetrically. In the center of the cylinder head 6, a plug insertion hole 9 for mounting an ignition plug that projects into the combustion chamber of each cylinder 1 from directly above is formed.

Since both the valve operating mechanisms 7 and 8 have the same structure, only the valve operating mechanism 7 on the intake side will be described. The rocker shaft 10 fixed to the cylinder head 6 has three parts for each cylinder in the shaft 10. Rocker arms 11 to 13 are pivotally supported adjacent to each other so as to be swingable and capable of being displaced relative to each other. The rocker shaft 10 is fitted and supported by supporting portions 19 a and 19 b provided at both ends of the cylinder head 6 and supporting portions 20 provided between the cylinders 1.

As also shown in FIG. 2, a cam shaft 14 is fastened above the rocker arms 11 to 13 with a cam support portion 15 having a semicircular cross section formed in the cylinder head 6 and on the cam support portion. It is rotatably supported by a cam holder (not shown). The cam support portion 15 has a hole 15a for inserting a bolt for fastening the cylinder head 6 to the cylinder block.
Has been drilled. On the camshaft 14, low speed cams 16 and 17 with a small lift and high speed cams 18 with a large lift are integrally formed. Further, in the information of the cam shaft 14, an oil supply pipe which defines an oil supply passage for lubricating a sliding contact surface of a cam and a rocker arm described later is arranged.

A corresponding cam 16 is provided on the upper surface of each rocker arm 11 to 13.
Cam slippers 21 to 23, which are in sliding contact with each other, are integrally formed. Further, tappet screws 24 and 25 are respectively screwed to the free ends of the first and second rocker arms 11 and 12 which are in sliding contact with the low speed cams 16 and 17, and the valve springs 28 and 25 are attached to the lower ends thereof via retainers 26 and 27. , 29, the upper ends of the intake valves 2 and 3 urged in the valve closing direction are in contact with each other. On the other hand, the first
The third rocker arm 13 slidingly contacting the high speed cam 18 arranged between the second rocker arms 11 and 12 is contacted with a lost motion spring (not shown) at its lower end to apply an upward biasing force.

As well shown in FIG. 3, the connection switching device 30 is built in the adjacent first to third rocker arms 11 to 13, and each rocker arm 11 to 11 is driven when the engine is operated at a low speed.
Although the 13 swings separately, they are integrally connected during high speed operation to drive the pair of intake valves 2 and 3 to open. In this connection switching device 30, a bottomed first guide hole 31 opening to the side of the third rocker arm 13 is bored inside the first rocker arm 11 in parallel with the rocker shaft 10, and is slidable in the first guide hole 31. Has a first switching pin 32 that fits in the. A hydraulic chamber 33 is defined in the bottom of the first guide hole 31, and the inside of the rocker shaft 10 is provided through a passage 34 provided in the first rocker arm 11 and an oil supply hole 35a opened at the side of the hollow rocker shaft 10. Is communicated with the oil supply passage 35 provided in the.

In the third rocker arm 13, a second guide hole 36 having the same diameter and concentric with the first guide hole 31 is provided in parallel with the rocker shaft 10 at a stationary position where the cam slipper is in sliding contact with the base circle of the cam. In addition, the second switching pin 37 is slidably fitted inside so that one end of the second switching pin 37 contacts the first switching pin 32. Similarly, a bottomed third guide hole 38 is bored in the second rocker arm 12, and a stopper pin 39 is slidable therein, with one end of the stopper pin 39 abutting the other end of the second switching pin 37. Is fitted to. The stopper pin 39 has a shaft portion 41 fitted into a guide sleeve 40 fitted in the bottom portion of the third guide hole 38, and is constantly urged by the return spring 42 toward the third rocker arm 13.

In addition, as shown in FIG. 1, an intake port 62 is formed at one end of the cylinder head 6 and has an opening 62 on the end face 61. The intake port is fixed to the support part 19 a via a communication passage 63. Side and exhaust side rocker shafts 10 communicate with respective oil supply passages 35 that open at one end 10a. On the end face 61,
As will be described later, a switching control valve 64 for selectively switching and supplying hydraulic pressure sent from an oil pump driven by the engine to the oil supply port 62 is attached. The switching control valve 64 has its inlet connected to an oil gallery 65 as shown in FIG. 3, and oil pressure is supplied from an oil pan 66 by an oil pump 67 via a relief valve 68, an oil filter 69 and an oil cooler 70. It has become so.

As shown in FIG. 4, a hole for fitting and supporting the other end 10b of the rocker shaft 10 to the support portion 19b provided at the end of the cylinder head 6 on the side opposite to the switching control valve 64. 7
1 is provided, and an attachment hole 72 of an orifice member is vertically formed so as to communicate with the hole 71. On the side of the end 10b of the rocker shaft 10 that fits into the hole 71, a connection hole 73 having a diameter substantially the same as the mounting hole 72 for connecting the rear end of the oil supply passage 35 to the oil supply passage for high-speed lubrication described later is provided. It has been opened. This connection hole
The position of both the axial direction and the rotation direction of the rocker shaft 10 is determined so that the passage inlet 34a of each rocker arm connection switching means 30 and the oil supply hole 35a of the rocker shaft 10 are aligned with each other at a position matching the mounting hole 72. It is provided.

As shown in FIG. 5, the rocker shaft 10 is positioned with the connecting hole 73 aligned with the mounting hole 72, and the orifice member 74 is inserted into the mounting hole 72 from above. The orifice member 74 is made of a pin-shaped member having a throttle inside, and an inlet port 75 is formed at the tip of the orifice member 74, which is open to the side surface and the lower surface. A concave groove 77 is provided around an enlarged diameter portion 76 provided on the upper portion of the orifice member 74, and an O-ring 78 is attached.

The orifice member 74 has a lower end of the expanded diameter portion 76 and a step portion of the mounting hole 72.
The distal end portion provided with the inlet port 75 is engaged with 79 and is inserted to a position where it penetrates the connection hole 73 of the rocker shaft 10 and projects into the oil supply passage 35. By thus engaging the tip of the orifice member 74 with the connection hole 73, the rocker shaft
The 10 can be fixed in position with respect to both its axial and rotational directions. Therefore, it is preferable to secure the wear resistance by using a material such as steel for the orifice member 74. Further, since the diameters of the mounting hole 72 and the connection hole 73 are formed to be slightly larger than the outer diameter of the orifice member 74, a slight gap is formed between the outer peripheral surface of the orifice member and the inner peripheral surface of each hole. However, since the oil leakage is prevented by the O-ring 78 mounted on the expanded diameter portion 76, the operation of each rocker arm connection switching means 30 is not affected.

A cam holder 81 for rotatably supporting the cam 14 is arranged on the upper end of the support portion 19b, and a low speed lubrication oil passage 82 is provided thereon.
And an oil supply pipe member 84 that defines a high speed lubrication oil supply passage 83 and is fastened to the cylinder block 6 by a bolt 85. A communication passage 86 is provided in the cam holder 81, and the outlet port 87 of the orifice member 74 is connected to the high-speed lubrication oil supply passage 83. The oil supply passage 83 is provided with an injection hole 88 for showering the lubricating oil in a position corresponding to the high speed cam 18.

On the other hand, the low speed lubrication oil supply passage 82 is connected to an oil passage 90 which is branched from the oil gallery 65 and has an orifice 89 in the middle thereof. The oil supply passage 82 is provided with injection holes 91 for injecting the lubricating oil in a shower type at positions corresponding to the cams 16 to 18. Furthermore, the low speed lubrication oil supply passage 82 also lubricates the cam journal 14a via the passage 92.

Since the switching control valve 64 is closed when the engine is operating at a low speed, the oil pressure is not supplied to the oil supply passage 35. Therefore, as shown in FIG. 3, the pins 32, 37, 39 are in a position biased toward the hydraulic chamber 33 side by the return spring 42, and the rocker arms 11-13 are moved by the corresponding cams 16-18 to each other. Relative angular displacement. In this case, the oil supplied to the oil gallery 65 by the oil pump 67 is supplied to the low speed lubrication oil supply passage 82 from the oil passage 90 via the orifice 89, and is supplied to the respective cams 16 to 18 and the corresponding rocker arms 11 to 13. Lubricate the sliding surface and the cam journal 14a.

During high-speed operation of the engine, the switching control valve 64 is opened, and oil is pumped from the oil supply port 62 to the oil supply passage 35 via the communication passage 63. When the hydraulic pressure is supplied to the hydraulic chamber 33, the first and second hydraulic pressure chambers are supplied.
The switching pins 32 and 37 are fitted into the second guide hole 36 and the third guide hole 38 against the urging force of the return spring 42, and the rocker arms 11 to 13 are integrally connected. Refueling passage
The oil supplied to 35 is the rocker arm connection switching means.
A connection hole provided at the rear end of the oil supply passage while operating 30
The flow rate is throttled from 73 by the orifice 74 and supplied to the oil supply passage 83 for high speed lubrication, and the high speed cam 18 and the third rocker arm 13
Lubricate the sliding surface with.

[Advantages of the Invention] As described above, according to the present invention, in the valve operating mechanism of the internal combustion engine capable of switching the operating state of the valve, the orifice member is engaged with the connection hole provided at the end of the rocker shaft. By doing so, the oil supply passage for high speed lubrication can be connected to the rear end of the oil supply passage of the rocker arm connection switching means via the orifice, and at the same time, the rocker shaft can be positioned and fixed in both the axial direction and the rotation direction, and the cam holder can also be positioned. Since they can be fixed together, a plurality of components can be positioned by one orifice member (throttle). Therefore, it is possible to reduce the number of parts, reduce the number of processing and assembling steps to reduce the manufacturing cost, and simplify the structure to achieve a compact layout.

[Brief description of drawings]

FIG. 1 is a plan view showing a valve operating mechanism of an internal combustion engine according to the present invention. FIG. 2 is a view taken along the line II-II in FIG. FIG. 3 is a circuit diagram showing an oil supply system of the valve mechanism according to the present invention. FIG. 4 is a sectional view taken along line VI-VI in FIG. FIG. 5 is a cross-sectional view showing an assembled state of the orifice member by partially enlarging FIG. 1 ... Cylinder 2, 3 ... Intake valve 4, 5 ... Exhaust valve, 6 ... Cylinder head 7, 8 ... Valve mechanism, 9 ... Plug insertion hole 10 ... Rocker shaft, 11 ... 1st rocker arm 12 …… 2nd rocker arm 13 …… 3rd rocker arm 14 …… camshaft, 14a …… cam journal 15 …… cam support part, 15a …… hole 16, 17 …… low speed cam 18 …… high speed Cams 19a, 19b, 20 ...... Support parts 21-23 ...... Cam slippers 24, 25 ...... Tappet screws 26, 27 ...... Retainers 28, 29 ...... Valve spring 30 ...... Connection switching device, 31 ...... 1st guide Hole 32 ...... First switching pin, 32a, 32b ...... End 33 ...... Hydraulic chamber, 34 ...... Passage 34a …… Inlet, 35 …… Oil supply path 35a …… Oil supply hole, 36 …… Second guide hole 37 …… Second switching pin, 38 …… Third guide hole 39 …… Stopper pin, 40 …… Guide sleeve 41 …… Shaft, 42 …… Returns Ring 61 …… End face, 62 …… Filling port 63 …… Communication passage, 64 …… Switching control valve 65 …… Oil gallery, 66 …… Oil pan 67 …… Oil pump, 68 …… Relief valve 69 …… Oil filter , 70 …… Oil cooler 71 …… Hole, 72 …… Mounting hole 73 …… Connection hole, 74 …… Orifice member 75 …… Inlet port, 76 …… Expanded part 77 …… Recessed groove, 78 …… O-ring 79 …… Step, 81 …… Cam holder 82 …… Low speed lubrication oil supply passage 83 …… High speed lubrication oil supply passage 84 …… Oil supply pipe member, 85 …… Bolt 86 …… Communication passage, 87 …… Outlet port 88… … Spout hole, 89 …… Orifice 90 …… Oil passage, 91 …… Spout hole 92 …… Passage

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Claims (1)

[Scope of utility model registration request] 1. A plurality of rocker arms pivotally supported by a rocker shaft and swingably driven by a cam on a cam shaft that rotates in synchronization with a crankshaft, and the adjacent rocker arms are selectively actuated by the action of hydraulic pressure. A rocker arm connection switching means for connecting or disconnecting to a rocker arm, a hydraulic oil supply passage provided inside the rocker shaft for supplying hydraulic pressure to the rocker arm connection switching means, and a cam holder supporting the cam shaft. A valve for an internal combustion engine including an oil supply passage connected to a rear end of the hydraulic oil supply passage through a throttle, and a lubricating oil supply passage for lubricating the cam connected to the oil supply passage in the cam holder A mechanism, wherein a throttle member that forms the throttle is penetrated from a cylinder head side in a direction orthogonal to a pipe wall of the rocker shaft, and is provided in a concave portion of the cam holder. A valve mechanism for an internal combustion engine, wherein the rocker shaft and the cam holder are positioned by being inserted.