JPH1113441A - Valve operation device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely seal one end part of an oil path in a locker shaft by providing a fastening member for fixing one end part of the locker shaft to a bearing part in relation to a part having a sealing member press fitted with one end part of the oil path of the locker shaft. SOLUTION: A locker shaft 12 for supporting a locker arm 14 to be freely swung is fitted and supported by bearing parts 38, 40,...46 formed in a cylinder head 36 along the axial direction of the locker shaft 12 at specified intervals. In this case, a specified gap is formed in the outer peripheral surface of the locker shaft 12 in the forming positions of the bearing parts 38 and 46 of both ends and air bleeder holes 12C and 12D formed at the bearing part, and one end of the gap is connected to a lifter route communicated with an oil pan. The locker shaft 12 is fixed in a terminal side more than the air bleeder hole 12D by inserting a bolt 48. Then, by press fitting a plug member 50 between the air bleeder hole 12D and the bolt hole in an oil path 12A, one end of the oil path 12A is closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head having a valve head variable mechanism for varying a valve head of an intake valve or an exhaust valve provided in an intake passage or an exhaust passage of an engine in accordance with an operation state of the engine. The present invention relates to a valve operating device for an engine.

[0002]

2. Description of the Related Art It is known that a valve operating device for an engine is controlled so that the lift characteristics of an intake valve or an exhaust valve are made different depending on a low-speed operation state, a medium-speed operation state and a high-speed operation state of the engine. I have. Such devices are:
For example, as disclosed in Japanese Patent Application Laid-Open No. Hei 8-210113, a plurality of intake valves (or exhaust valves) provided in one cylinder arranged in a cylinder head of an engine are provided with a plurality of two or more different shapes. A camshaft having a cam and a plurality of rockers supported on a rocker shaft arranged in parallel to the camshaft and transmitting a pressing force based on a head characteristic determined by the rotational movement of these cams to an end of the valve stem. There has been proposed one including an arm and a selective connection mechanism for selectively connecting and disconnecting adjacent rocker arms to each other according to the operating state of the engine.

[0003] The selective connection mechanism includes, for example, a rocker arm which is swung by a low speed cam, and a high speed sub rocker arm which is provided adjacent to the rocker arm and is swung by a high speed cam. A lever member is rotatably supported by the rocker arm along the central axis of the rocker shaft corresponding to the sub rocker arm.

When the engine is operating at a high speed, the other end of the lever member is pressed by a piston member provided in the rocker arm opposite the other end of the lever member, so that one end of the lever member is opposed to the other end. The sub rocker arm is engaged with the engaged portion. By this, the rocker arm and the sub rocker arm are connected, and the rocker arm is swung by the high speed cam, and the lift characteristic of the intake valve or the exhaust valve changes from the lift characteristic for low speed operation to the lift characteristic for high speed operation. Has been proposed.

[0005] A piston member provided in such a rocker arm is slidably disposed in a pressure chamber to which a working oil pressure is selectively supplied through an oil passage provided in the rocker shaft. One end of the oil passage in the rocker shaft is closed by a plug member that is pressed into the oil passage as described in the above-mentioned publication, and the other end of the oil passage is provided with a predetermined end. It is connected to a switching valve that selectively supplies the regulated hydraulic pressure.

When the operating state of the engine is shifted from the low speed range to the high speed range, the switching valve is controlled to switch, and the operating oil pressure from the oil passage through the through hole formed along the radial direction of the rocker shaft is applied to the pressure chamber. , The tip of the piston member is moved to press the other end of the lever member.

[0007]

If the interference at the time of press-fitting between the plug member and the oil passage is insufficient, the switching valve is controlled as described above, and the operating oil pressure is supplied to the oil passage in the rocker shaft. When the impact force is applied to one end of the oil passage in the rocker shaft and hydraulic oil leaks from between the outer peripheral surface of the plug member and the inner peripheral surface of the oil passage, or
There is a possibility that the tightening force of the plug member pressed into the end of the rocker shaft may be reduced.

In such a case, it is conceivable that the interference during press-fitting is relatively large. However, as the interference increases, the rocker shaft acts on the rocker shaft along its axial direction during press-in processing. The load to be applied becomes large, and the accuracy of the straightness or roundness of the rocker shaft deteriorates, and there is an inconvenience that finishing is further required to achieve a predetermined accuracy.

In view of the above problems, the present invention is directed to a variable valve lift for varying a valve lift of an intake valve or an exhaust valve provided in an intake passage or an exhaust passage of an engine in accordance with an operation state of the engine. A valve operating device for an engine having a mechanism and arranged in a cylinder head, wherein a tightening margin at the time of press-fitting between a plug member and an oil passage in a rocker shaft is relatively large, and It is an object of the present invention to provide an engine valve operating device capable of reliably closing one end of an oil passage.

[0010]

In order to achieve the above object, a valve operating device for an engine according to the present invention comprises a valve lift of an intake valve or an exhaust valve provided in an intake passage or an exhaust passage of the engine. A bearing portion that supports at least one end of a rocker shaft that has an oil passage therein that communicates with a valve lift variable mechanism that varies in accordance with an operation state and extends along the center axis direction, and one of the oil passages of the rocker shaft. A closing member that is press-fitted into the end and closes one end of the oil passage, and is radially spaced apart from the end of the one end of the rocker shaft with respect to a portion of the rocker shaft where the closing member is provided in the oil passage. And a fastening member that is inserted into a through hole provided along the hole and fixes at least one end of the rocker shaft to the bearing.

Further, a through-hole for allowing air bubbles contained in oil supplied to the oil passage of the rocker shaft and air in the oil passage to escape to the outside may be provided in the vicinity of the portion where the closing member is provided.

[0012]

FIG. 3 and FIG. 4 show an example of a valve operating device of an engine according to the present invention.

The examples shown in FIGS. 3 and 4 are provided in a cylinder head of an in-line four-cylinder engine main body, not shown, and have a valve mechanism corresponding to one of the four cylinders. 3 shows the intake passage side in FIG.
The configuration of the valve mechanism on the exhaust passage side is as follows.
Since the configuration is the same as that of the valve mechanism on the intake passage side, the description thereof is omitted.

The driving method of the valve mechanism is, for example, OHC (o
ver head camshaft) method and 2
The two intake valves are driven to open and close.

[0015] The valve mechanism includes an arm portion 1 which is in contact with an end of the valve stem of each of the intake valves 18A and 18B.
A rocker arm 14 having 4A and 14B and rotatably supported by the rocker shaft 12; a sub rocker arm 16 disposed at a substantially central position between the arm portions 14A and 14B of the rocker arm 14; The rocker arm 14 includes a camshaft 10 disposed above the sub rocker arm 16 in parallel to the rocker shaft 12 and rotated in conjunction with a crankshaft of the engine body.

The rocker arm 14 is rotatably supported by the rocker shaft 12 fitted in a hole 14a provided at the base end thereof. A pair of bearing portions 14E facing each other at a predetermined interval along the axial direction of the rocker shaft 12 are provided on the camshaft 10 side of the periphery of the hole 14a.

The base end of the sub rocker arm 16 is disposed between the pair of bearings 14E. The base end of the sub rocker arm 16 is rotatably supported by a support shaft 24 fitted in the hole 16a and is arranged on the same axis. Both ends of the support shaft 24 are fitted into the through holes 14e of the pair of bearing portions 14E. Both ends of the support shaft 24 are respectively locked to a pair of bearing portions 14E by retaining rings.

At the positions of the arm portions 14A and 14B of the rocker arm 14 facing the cam shaft 10, the cams 10A and 1
Cam followers 14a and 14b to which OB slides are provided.

The tip of the arm 14A and the arm 14
Abutting portions 14G and 14H that abut against ends of the valve stems of the intake valves 18A and 18B, respectively, are provided at portions of the distal end of B that face the intake valves 18A and 18B.

The intake valves 18A and 18B are shown in FIG.
As shown in FIG. 4 and FIG. 4, coil springs 20A and 20B held by retainers provided at the distal end of the valve stem are biased toward contact portions 14G and 14H, respectively.

On the upper surface of the sub rocker arm 16 facing the camshaft 10, as shown in FIG.
A cam follower 16A is provided which is slidably contacted with the cam 10C of the camshaft 10. As shown in FIG. 5, an engagement portion 26 of a lever member 26 described later is provided on a lower surface of the sub rocker arm 16 facing the cam follower 16A.
A recess 16C is provided as an engaged portion with which C is engaged.

A concave portion 16B for accommodating a coil spring 28 disposed between the rocker arm 14 and the sub rocker arm 16 is provided in a lower surface portion connected to the concave portion 16C. Outer peripheral portion of coil spring 28 and concave portion 16B
A spring housing 31 is slidably provided on the inner peripheral surface of the recess 16B. One end of the coil spring 28 is inserted into the inner periphery of the spring housing 31 and the other end is inserted into the recess 16B.
The position is regulated by contacting the bottom of the. The coil spring 28 urges the sub rocker arm 16 toward the camshaft 10.

On the rocker shaft 12 side of the base end of the sub rocker arm 16, a projection is provided. When the protruding piece is engaged with the outer peripheral portion of the fitting hole 14a of the rocker arm 14, the elevation of the tip of the sub rocker arm 16 by a predetermined amount or more is restricted.

The camshaft 10 has cams 10A and 10B for setting the lift amounts of the intake valves 18A and 18B when the engine body is in a low-speed operation state. They are provided facing each other. Further, between the cam 10A and the cam 10B in the camshaft 10, when the engine body is in a high-speed operation state, the intake valve 1
The cam 10C for setting the lift amount of 8A and 18B is
The sub rocker arm 16 is provided facing the cam follower 16A along the axial direction. The maximum eccentricity of the cams 10A and 10B with respect to the axis of the camshaft 10 is smaller than the maximum eccentricity of the cam 10C.

As shown in FIG. 4, a pair of bearing portions 14F are provided at a substantially central portion of the lower portion of the rocker arm 14 facing the sub rocker arm 16.
Both ends of the support shaft 22 are supported by the pair of bearing portions 14F substantially in parallel with the camshaft 10 and the rocker shaft 12. Both ends of the support shaft 22 are respectively locked to the rocker arm 14 by retaining rings.

A lever member 26 is rotatably supported by the support shaft 22. The lever member 26 has an engaging portion 26C that is selectively engaged with the concave portion 16C of the sub rocker arm 16. Further, the engaging portion 2 of the lever member 26
In the vicinity of the portion where 6C is provided, a return piece 26B extending along the axis of the support shaft 22 is provided as shown in FIG. The return piece 26B is a plunger 3 to be described later.
2 is in contact with the tip.

In the rocker arm 14, between the rocker shaft 12 and the return piece 26C of the lever member 26,
As shown in FIG. 6, an accommodation portion 14J that accommodates the return spring 34 is provided. A plunger 32 is disposed at a distal end of a return spring 34 provided in the housing portion 14J, and a distal end protruding from the housing portion 14J contacts the return piece 26C.

As shown in FIG. 5, an oil passage 12 extending along the center axis of the rocker shaft 12 is provided inside the rocker shaft 12.
A is formed. Although not shown, the oil passage 12A is connected to a hydraulic circuit that supplies operating oil pressure and lubricating oil.

In the rocker arm 14, between the rocker shaft 12 and the portion facing the lever member 26,
A pressure chamber 14D communicating with a through hole 12B communicating with the oil passage 12A via a communication passage 14C is formed. Pressure chamber 14
A piston member 30 is slidably disposed on D.

The tip of the piston member 30 is connected to the oil passage 12A,
When the operating oil pressure is supplied to the pressure chamber 14D through the through-hole 12B and the communication passage 14C, as shown by a two-dot chain line in FIG. 5, the operating oil pressure is moved and protruded from the pressure chamber 14D to the outside. As a result, the end portion 26A of the lever member 26 is pressed, and thus the counter rocker arm 1
It will be rotated toward the sixth side.

On the other hand, the tip of the piston member 30 is
When an operating oil pressure of a predetermined pressure is not supplied through the 2A, the through hole 12B, and the communication passage 14C, the operating oil pressure is maintained in the pressure chamber 14D. Further, in a state where the distal end of the piston member 30 protrudes outward, when the operating oil pressure of a predetermined pressure is not supplied through the oil passage 12A, the through hole 12B, and the communication passage 14C, the lever member 26 is returned to the return spring 34. Of the return piece 26B by the urging force of the lever member 26.
5, the tip of the piston member 30 is made to coincide with the end face of the rocker arm 10 as shown by a solid line in FIG.

As shown in FIG. 2, the rocker shaft 12 is provided inside the cylinder head 36.
Are supported at bearings 38, 40, 42, 44, and 46 arranged at a predetermined interval along the center axis direction of the motor.

The other end of the rocker shaft 12 supported by the bearing 46 is provided with an air vent hole 12C formed along the radial direction thereof and communicating with the oil passage 12A. At one end of the rocker shaft 12 supported by the bearing portion 38, an air vent hole 12D having a diameter smaller than the diameter of the air vent hole 12C is provided.

As shown in FIG. 7, between the outer peripheral surface of the rocker shaft 12 and the portions of the inner peripheral surfaces of the bearing portions 38 and 46 facing the open ends of the air vent holes 12C and 12D, respectively. A predetermined gap 52 is formed on the entire circumference along the circumferential direction. One end of the gap 52 is connected to a return passage leading to an oil pan (not shown).

When the hydraulic oil is supplied to the oil passage 12A in the direction indicated by the arrow shown in FIG. 2, the air in the oil passage 12A and the air bubbles contained in the hydraulic oil are removed from the air vent holes 12C and 12D. 7 and the gap 52, and are smoothly discharged in the direction indicated by the arrow in FIG.

On the rocker shaft 12 supported by the bearing portion 38, at the end portion side of the portion where the through hole 12D is provided, through holes 12E and 12F into which the shaft portions of the bolts 48 are respectively inserted are formed in the radial direction. And are provided so as to face each other on the same straight line. Thereby, the bolt 4
8 is inserted into the through holes 12E and 12F and fitted into the female screw hole 38s of the bearing portion 38, whereby the rocker shaft 12 is positioned and fixed to the bearing portion 38.

As shown in FIG. 1, between the position where the air vent hole 12D faces the oil passage 12A and the position where the through holes 12E and 12F face each other, as a closing member for closing one end of the oil passage 12A, as shown in FIG. The plug member 50 is press-fitted. At this time, the distance Lb between the plug member 50 and the outer peripheral surface of the shaft of the bolt 48 is set to be smaller than the length La of the plug member 50 in the thickness direction.

Thus, even when a relatively large impact force due to the hydraulic oil is applied to the entire pressure receiving surface of the plug member 50, the moved plug member 50 can be connected to the bolt 48.
Of the oil passage 12
Dropping from one end of A will be avoided.

The bearing 38 of the rocker shaft 12
Is easily performed by the bolt 48.

Further, the axial fastening force of the bolt 48 is also applied between the outer peripheral surface of the plug member 50 and the inner peripheral surface of the oil passage 12A.
Can be made relatively small.

With this configuration, when the operating state of the engine is the low-speed operating state, the predetermined adjusted operating hydraulic pressure is not supplied to the oil passage 12A. Thereby, the piston member 3 in the pressure chamber 14D of the rocker arm 14 is
0 is maintained in the pressure chamber 14D, and the engaging portion 26C of the lever member 26 is disengaged from the recess 16C of the sub rocker arm 16. Therefore, rocker arm 1
4 are the cams 10A and 10A of the camshaft 10.
B is swung in response to the rotation of the intake valves 18A and 18B.
At the predetermined timing.

When the operating state of the engine is a high-speed operating state, a switching valve (not shown) is switched to supply the regulated hydraulic oil to the oil passage 12A. Thereby, when the hydraulic oil is supplied into the pressure chamber 14C through the through-hole 12B and the communication passage 14C, the piston member 30 in the pressure chamber 14D of the rocker arm 14 moves as shown by a two-dot chain line in FIG. The protrusion 26 protrudes outward and presses the end 26A of the lever member 26, and the engagement portion 26C of the lever member 26 is engaged with the recess 16C of the sub rocker arm 16. Therefore, the rocker arm 14 and the sub rocker arm 16 are connected to each other to form the rocker arm 1.
4 is swung in response to the rotation of the cam 10C on the camshaft 10, and causes the intake valves 18A and 18B to open and close at a predetermined timing.

Further, when the operation state of the engine is shifted from the high-speed operation state to the low-speed operation state, the switching valve is switched and the supply of the operating oil pressure to the oil passage 12A is stopped. Thereby, the return piece 26B of the lever member 26 is pressed by the plunger 32, and the lever member 26 is returned to the initial position shown in FIG.

Therefore, the adjusted operating pressure oil is supplied to the oil passage 12A.
Is supplied to the plug member 50 in the oil passage 12A.
Even when the rocker arm 14 is moved by applying an impact pressure along the axial direction of the rocker arm 14, the position of the plug member 50 is restricted by the shaft of the bolt 48.

[0045]

As is apparent from the above description, according to the valve operating device for an engine according to the present invention, the closing member is press-fitted into one end of the oil passage of the rocker shaft and one end of the oil passage is inserted. And the fastening member is inserted into a through-hole provided along the radial direction and spaced apart from the end of one end of the rocker shaft with respect to the portion of the oil passage of the rocker shaft where the closing member is provided. Since at least one end of the rocker shaft is fixed to the bearing portion, the closing member is applied with a fastening force by the fastening member, and the movement of the closing member in the center axis direction is regulated by the fastening member. One end of the oil passage in the rocker shaft can be reliably closed without relatively large interference during press-fitting between the plug member and the oil passage in the rocker shaft. That.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing one end of a rocker shaft used in an example of a valve operating device of an engine according to the present invention, together with a part of a cylinder head.

FIG. 2 is a cross-sectional view showing a rocker shaft used in an example of the valve operating device of the engine according to the present invention, together with a part of a cylinder head to which the rocker shaft is applied.

FIG. 3 is a plan view showing a main part of an example of the valve operating device of the engine according to the present invention.

FIG. 4 is a front view of the example shown in FIG. 3;

FIG. 5 is a sectional view of the example shown in FIG. 3;

FIG. 6 is a sectional view of the example shown in FIG. 3;

FIG. 7 is a partial sectional view of the example shown in FIG.

[Explanation of symbols]

 Reference Signs List 10 camshaft 12 rocker shaft 12A oil passage 12B through hole 12C, 12D air vent hole 12E, 12F through hole 14C communication path 14 rocker arm 14D pressure chamber 16 sub rocker arm 18A, 18B intake valve 38 bearing part 38s female screw hole 48 bolt 50 plug Element

Continued on the front page (72) Inventor Asaichi Kobayashi 1370 Onna, Atsugi-shi, Kanagawa Prefecture Inside Unisia Gex Co., Ltd. Maki Toriumi 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Inside Nissan Motor Co., Ltd.

Claims (2)

[Claims] 1. An oil passage extending along a central axis direction communicating with a valve lift variable mechanism that varies a valve lift of an intake valve or an exhaust valve provided in an intake passage or an exhaust passage of an engine in accordance with an operation state of the engine. A bearing portion for supporting at least one end of a rocker shaft having therein a rocker shaft; a closing member press-fitted into one end of an oil passage of the rocker shaft and closing one end of the oil passage; At least one end of the rocker shaft is inserted into a through hole provided along the radial direction and spaced apart from a portion of the oil passage of the shaft where the closing member is provided at a terminal side of one end of the rocker shaft. And a fastening member for fixing the valve member to the bearing portion. 2. A hole through which air bubbles contained in oil supplied to an oil passage of the rocker shaft and air in the oil passage to the outside are provided near a portion where the closing member is provided. The valve operating device for an engine according to claim 1, wherein