JPH11264304A - Cylinder head structure for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent increase of size of a cylinder head which may be caused by installation of an oil control valve, while securing satisfactory control response of a valve timing adjusting device. SOLUTION: In this structure, an operation oil control means 21 is arranged along an axis on an upper position of a cam shaft 1. The operation oil changed over by the operation oil control means 21 is supplied to a cam phase adjusting means for adjusting the phase. Since the operation oil control means 21 is located on the upper position of the cam shaft 1, oil passage length to the cam phase adjusting means attached to the cam shaft 1 is short. In addition, since the upper position of the cam shaft 1 is not used except that one of the sides of rocker arms 16, 17 are abutted thereageinst, it is unnecessary to secure specific space for installation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head structure of an internal combustion engine provided with a valve timing adjusting device for adjusting the opening / closing timing of an intake valve and an exhaust valve, and particularly to an oil control valve (hereinafter referred to as "OCV").
It is related to the installation position of.

[0002]

2. Description of the Related Art Conventionally, a valve timing adjusting apparatus of this type has a so-called dual overhead cam for exclusively opening and closing an intake / exhaust valve with a separate camshaft for the purpose of freely adjusting a valve overlap. Shaft (D
(OHC) type internal combustion engines. However, in order to respond to recent demands such as fuel saving and reduction of CO ² emission, to reduce the idling speed, a single overhead camshaft (hereinafter referred to as “SOHC”) fixed to overlap is rather used. Has been proposed to employ a valve timing adjusting device in an SOHC internal combustion engine.

[0003]

However, when a valve timing adjusting device is combined with an SOHC type internal combustion engine, there arises a problem in an installation position of an OCV for switching and controlling hydraulic oil to an actuator portion. That is, as is well known, the actuator section is provided on the cam pulley, and is supplied with hydraulic oil from an existing oil pump of the internal combustion engine to adjust the phases of the cam pulley and the camshaft with respect to the crankshaft. The direction of adjusting the cam phase is OC
In order to ensure a good control response, it is necessary to arrange the OCV at a position close to the actuator section and minimize the oil path length between the two.

However, in the SOHC type internal combustion engine, members such as a rocker arm and a rocker shaft for supporting the rocker arm are arranged around the camshaft because of the structure of opening and closing the intake and exhaust valves via the rocker arm by the camshaft. However, if the OCV is simply installed avoiding these members, the oil passage length with the actuator unit becomes longer, the control response is deteriorated, and the installation of the OCV may cause the cylinder head to become larger. was there.

An object of the present invention is to provide a cylinder head structure of an internal combustion engine which can prevent a large cylinder head portion due to the installation of an OCV while ensuring a good control response of a valve timing adjusting device. Is to do.

[0006]

In order to achieve the above object, according to the present invention, a common camshaft is configured to open and close an intake valve and an exhaust valve via a rocker arm. Hydraulic oil control means is provided along the axis of the camshaft, and the hydraulic oil switched and controlled by the hydraulic oil control means is supplied to the cam phase adjusting means to adjust the phase of the camshaft. Since the hydraulic oil control means is located above the camshaft,
The oil path length up to the cam phase adjusting means attached to the camshaft can be set to be short, and the upper position of the camshaft is not used originally because only one side of the rocker arm is in contact with the camshaft. Hydraulic oil control means can be installed without securing a space.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment)
A first embodiment embodied as a cylinder head structure of a valve cross-flow SOHC internal combustion engine will be described. FIG.
As shown in FIG. 2 and FIG. 2, the camshaft 1 of the internal combustion engine is formed by fixing a large number of journals 2a and cams 2b to a hollow shaft 2, and the front end (left side in FIG. A pulley mounting portion 3 integrally formed with 3a is fitted and fixed. The camshaft 1 is attached to the cylinder head 4 with the journal portions 2a and 3a supported by the bearing portion 5 of the cylinder head 4 so as to be rotatable and immovable in the axial direction. The front end of the pulley mounting portion 3 projects forward from the cylinder head 1, and the boss portion 6 a of the timing pulley 6 is rotatably fitted therein.
Is connected to a crankshaft (not shown) via a timing belt 7 and is driven to rotate about the axis of the camshaft 1 in the direction of the arrow in FIG. Reference numeral 8 denotes an oil seal.

An actuator 9 as a cam phase adjusting means is attached to one side of the timing pulley 6. The actuator section 9 changes the phase of the camshaft 1 with respect to the timing pulley 6 to adjust the opening / closing timing of the intake / exhaust valves 19 and 20 described later. The configuration itself is directly related to the gist of the present invention. Since there is no, only the outline will be described.

As shown in FIG. 2, the inside of a housing 10 of the actuator section 9 is formed in a substantially cross shape around the axis of the camshaft 1, and the center of a vane rotor 11 disposed in the housing 10 is a cam bolt 12. Is fixed to the pulley mounting portion 3 of the camshaft 1. The vane rotor 11 has a substantially cross shape with four vanes 11a, and is constantly urged to the retard side by a torsion coil spring 13. An advance hydraulic chamber 14 is formed on the retard side of each vane 11a, and a retard hydraulic chamber 15 is formed on the advance side, and when hydraulic oil is supplied into the advance hydraulic chamber 14, virtual pressure is generated by the hydraulic pressure. As shown by the line, the vane rotor 11 rotates to the advance side,
The phase of the camshaft 1 with respect to the timing pulley 6 is also changed to the advance side, and when hydraulic oil is supplied into the retard hydraulic chamber 15, the vane rotor 11 rotates to the retard side as shown by the solid line due to the hydraulic pressure. As a result, the phase of the camshaft 1 is also changed to the retard side.

On the other hand, as shown in FIGS. 3 to 5, two intake side rocker arms 16 are provided for each cylinder on the upper left side of the camshaft 1, and one intake rocker arm 16 is provided for each cylinder on the upper right side of the camshaft 1. Are arranged in the axial direction of the camshaft 1, respectively.
Reference numeral 17 is pivotally attached to two rocker shafts 18 arranged in parallel with the camshaft 1. Rollers 16a and 17a are provided at the inner ends (on the camshaft 1 side) of the intake-side rocker arm 16 and the exhaust-side rocker arm 17, and individually abut on the cam 2b of the camshaft 1. The outer end of the intake-side rocker arm 16 (opposite the camshaft 1) abuts on the intake valve 19 via an adjustment bolt 16b for adjusting the valve clearance, and the outer end of the exhaust-side rocker arm 17 branches into two forks. It is in contact with the exhaust valve 20 via the adjustment bolt 17b.
Therefore, when the camshaft 1 rotates, the rocker arms 16 and 17 swing at timings following the shape of the cam 2b to open and close the intake valve 19 and the exhaust valve 20 of each cylinder.

As shown in FIG. 5, a base 22 of an OCV 21 as hydraulic oil control means is disposed on a bearing 5 for supporting the camshaft 1 with the rocker shaft 18 interposed therebetween. The shaft 18 is fastened together with the bearing portion 5 by a fixing bolt 18a. As shown in FIGS. 1 and 4, a sleeve 23 of the OCV 21 is integrally formed on the base 22, and the sleeve 23 is
A solenoid 24 is attached to the rear of the vehicle. The sleeve 23 and the solenoid 24 extend rearward (to the right in FIG. 1) from the base 22, form a columnar shape that is long in the front-rear direction as a whole, and are located on the intake side rocker arm 16 and the exhaust side rocker arm 17. . That is, OCV2
1 is located directly above the camshaft 1 and has a base 2
2 to avoid interference with the rocker arms 16 and 17.

As shown in FIGS. 3 and 5, one end of an oil pipe 25 is connected to a right side surface of the cylinder head 4.
The oil pipe 25 is always supplied with hydraulic oil from an oil pump (not shown) as hydraulic oil supply means for the internal combustion engine. A gallery 26 communicating with one end of an oil pipe 25 is provided through the cylinder head 4, and the other end of the gallery 26 is connected to the OCV 21 via an oil pipe 27.
And is opened in the sleeve 23 as a supply port 33b as shown in FIG.

The OCV 21 is configured as a so-called spool valve. As shown in FIG. 6, a spool 29 is disposed in the sleeve 23 so as to be movable back and forth, and a drain cavity 30a, a supply cavity 30
b, three cavities of the drain cavity 30c are:
They are formed on the entire circumference at predetermined intervals in the axial direction. The spool 29 is urged rearward by a compression coil spring 32 which is prevented from falling off by a snap ring 31, and is driven forward by a solenoid 24 so that the two can be held at an arbitrary position where both are balanced. Here, the leading end of the stroke of the spool 29 is an advance switching position, the rear end of the stroke is a retard switching position, and the center of the stroke is a neutral switching position. In FIG. 6, the retard switching position is indicated by a virtual line, and the neutral switching position is indicated by a solid line.

A pair of drain ports 33a and 33c are provided at an upper portion in the sleeve 23 at a predetermined interval in the front-rear direction, and a lower portion in the sleeve 23 is also provided with a first port at a predetermined interval in the front-rear direction. Advance oil passage 34 and first retard oil passage 3
One end of 5 is formed with an opening. And the spool 29
Is in the neutral switching position shown by the solid line in FIG. 6, the first advance oil passage 34 and the first retard oil passage 35 are respectively closed on the outer periphery of the spool 29, and the retard angle shown by the phantom line in FIG. In the switching position, the first retard oil passage 35 communicates with the supply port 33b through the supply cavity 30b, and the first advance oil passage 34 communicates with the drain port 33a through the front drain cavity 30a. . Further, although not shown, at the advance switching position, the first advance oil passage 34 communicates with the supply port 33b via the supply cavity 30b, and the first retard oil passage 35 communicates with the rear drain cavity 30c. Through the drain port 33c.

As shown in FIGS. 1 and 6, the first advance oil passage 34 and the first retard oil passage 35 are formed parallel to each other and forward. The front end of the first advance oil passage 34 is
A second advance oil passage 36 extending in the vertical direction, an oil groove 37 on the outer periphery of the pulley attachment portion 3, a third advance oil passage 38 formed in the pulley attachment portion 3, and a fourth oil passage penetrating the cam bolt 12. Each of the advance hydraulic chambers 14 communicates with the advance hydraulic chambers 14 via an advance oil passage 39 and a fifth advance oil passage 40 formed in the vane rotor 11. Similarly, the front end of the first retardation oil passage 35 includes a second retardation oil passage 41, an oil groove 42, a third retardation oil passage 43 of the pulley mounting portion 3, and a fourth retardation oil passage of the vane rotor 11. 44
, Each of which communicates with each of the retard hydraulic chambers 15.

On the other hand, a rocker cover 46 is fixed to the upper surface of the cylinder head 4 via a packing 45, and the camshaft 1 and the rocker arm 1 are fixed by the rocker cover 46.
Members such as 6, 17 and the OCV 21 are hidden from the outside. A wiring 47 connected to the rear part of the solenoid 24 is connected to an EC (not shown) for controlling a fuel injection amount and an ignition timing of the internal combustion engine via a connector 48 fixed to a rocker cover 46.
U (engine control unit), and the excitation of the solenoid 24 is controlled based on a command from the ECU.

Next, the operation of the internal combustion engine configured as described above, particularly, the operation of the valve timing adjusting device will be described.
During operation of the internal combustion engine, the rocker arms 16 and 17 swing with the rotation of the camshaft 1 to open and close the intake valve 19 and the exhaust valve 20 of each cylinder. An optimum phase of the camshaft 1 (opening / closing timing of the intake / exhaust valves 19, 20) is obtained by the ECU based on the engine speed, the load, and the like at this time, and the excitation of the solenoid 24 of the OCV 21 is controlled to control the camshaft 1 The phase is adjusted to the advance side or the retard side.

That is, as shown by a virtual line in FIG. 6, when the excitation of the solenoid 24 is weakened and the spool 29 moves to the retard switching position by the compression coil spring 32, the hydraulic oil from the oil pump is supplied to the supply port. 33b, the supply cavity 30b, and the first retardation oil passage 35 to the fourth retardation oil passage 44, the oil is introduced into each retard hydraulic chamber 15, and the hydraulic pressure causes the vane rotor 11 to rotate to the retard side. The phase of the camshaft 1 is also adjusted to the retard side. At this time, the hydraulic oil in the advance hydraulic chamber 14 is supplied from the fifth advance oil passage 40 to the first advance oil passage 34,
It is discharged onto the cylinder head 4 through the drain cavity 30a and the drain port 33a.

When the excitation of the solenoid 24 is strengthened and the spool 29 moves to the advance switching position, the hydraulic oil from the oil pump is supplied to the supply port 33b,
The supply oil is introduced into each advance hydraulic chamber 14 via the supply cavity 30b, the first advance oil path 34 to the fifth advance oil path 40, and at the same time, the hydraulic oil in the retard hydraulic chamber 15 becomes the fourth retard oil. The fluid is discharged onto the cylinder head 4 through the passage 44 to the first retard oil passage 35, the drain cavity 30c, and the drain port 33c, and the phase of the camshaft 1 is adjusted to the retard side.

If the spool 24 is moved to the neutral switching position when the camshaft 1 reaches the target phase, the first advance oil passage 34 and the first retard oil passage 35 are closed, and The camshaft 1 can be held at the phase position. The valve timing adjusting device is controlled as described above. Here, the control response from the movement of the spool 29 of the OCV 21 until the hydraulic pressure is actually generated in the advance hydraulic chamber 14 or the retard hydraulic chamber 15 and the vane rotor 11 rotates is O
It is determined by the oil path length from the CV 21 to the advance hydraulic chamber 14 and the retard hydraulic chamber 15, and the shorter the oil path length, the better control response is obtained. In this embodiment, as is clear from FIGS. 1 and 4, the OCV 21 is located directly above the camshaft 1 by using the base 22 to avoid interference with the rocker arms 16 and 17. The oil path length to the advance hydraulic chamber 14 and the retard hydraulic chamber 15 is extremely short, and the phase of the camshaft 1 can be adjusted with good control response.

In addition, as apparent from FIG. 4, in the cross-flow SOHC internal combustion engine, the intake side rocker arm 16
And the inner end of the exhaust-side rocker arm 17 abuts on the camshaft 1 to form a valley therebetween.
The space above it is not originally used. And
In this embodiment, in the valleys of the rocker arms 16 and 17,
Since the column-shaped OCV 21 that is long in the front-rear direction is installed so as to fit from above, it is needless to say that it is not necessary to secure the space in the left-right direction and the front-rear direction for the installation of the OCV 21, and the rocker is also used in the vertical direction. Cover 4
It is sufficient to enlarge 6 slightly upward. As a result, extremely efficient packaging is realized, and the OC
It is possible to prevent the cylinder head 4 from becoming large due to the installation of V21.

(Second Embodiment) Next, a second embodiment in which the present invention is embodied as a cylinder head structure of a 4-valve counter-flow SOHC internal combustion engine will be described. The difference from the first embodiment lies in the configuration of the valve mechanism and the cylinder head 1.
01 and the installed state of the OCV 115, the internal structure of the actuator section 9 and the OCV 115 is not different from that of the first embodiment. Therefore, the common components are denoted by the same reference numerals and the description thereof will be omitted, and the differences will be mainly described.

As shown in FIGS. 7 and 8, one intake side rocker arm 102 and one exhaust side rocker arm 103 are arranged for each cylinder in the cylinder head 101, and each rocker arm 102, 103 is attached to a camshaft 104. Along the front and rear direction (up and down direction in FIG. 8), they are mounted on a common rocker shaft 105. Rollers 102a, 1 provided at one end of each rocker arm 102, 103
03a abuts on the camshaft 104, and adjust bolts 102b, 103b provided at the other end are connected to a slide member 107 via a ball joint 106.

Each slide member 107 is mounted on the cylinder head 1
The slide member 107 is provided with two intake valves 109 or two exhaust valves 110 immediately below the right and left sides of the slide member 107. The intake and exhaust valves 109 and 110 are vertically movably supported by a valve guide 111 and are constantly urged to the valve closing side by a valve spring 112. Is in contact with Although FIG. 7 shows the valve operating mechanism on the intake valve 109 side, the exhaust valve 110 side has exactly the same configuration.

Accordingly, when each rocker arm 102, 103 swings with the rotation of the camshaft 104, the corresponding slide member 107 is pressed downward against the urging force of the valve spring 112, and the intake valve 109 or the exhaust valve 1
10 is driven to open and close. In addition, 113 is the two valves 10
Adjustment bolts for adjusting the balance between the open and closed states of 9,110.

At the forefront of the cylinder head 101, a base 116 of an OCV 115 as hydraulic oil control means is fixed by two bolts 114. As in the first embodiment, the OCV 115 extends rearward from the base 116 to form a long columnar shape in the front-rear direction as a whole.
4, the rocker arms 102, 10
3 is located in a space that is not originally used because only one end is in contact therewith.

Although not described in detail, also in this embodiment, the OCV 115 includes the oil pipe 117 and the gallery 11.
8 to control the hydraulic oil supplied through
It is supplied to the actuator section 9 via the oil passage 19 and the retard oil passage 120 to adjust the phase of the camshaft 104. And
As in the first embodiment, the OCV 115 is
4, the oil path length to the actuator section 9 can be extremely short, and the phase of the camshaft 104 can be adjusted with a good control response. Further, since the OCV 115 is installed in a space directly above the camshaft 104 that is not originally used, it is not necessary to secure a space particularly for installation, and it is possible to prevent the cylinder head 101 from becoming large. it can.

In each of the above embodiments, the cylinder head structure of the four-valve internal combustion engine has been embodied.
SOHC that drives intake and exhaust valves on a common camshaft
The number of valves is not limited as long as it is a cylinder head of a type. For example, the cylinder head may be embodied as a two-valve or three-valve cylinder head structure. In each of the above embodiments, the OCVs 21 and 115 are configured as spool valves.
Although the actuator section 9 is configured as a vane type, the present invention is not limited to this. In short, OCV2
1, 115 need only be able to switch the hydraulic oil supplied to the actuator unit 9. Similarly, the actuator unit 9
It is sufficient that the phase of the camshaft 1 can be adjusted by hydraulic pressure. Therefore, their structures can be variously changed.

[0029]

As described above, according to the cylinder head structure of the internal combustion engine of the present invention, the hydraulic oil control means is located above the camshaft, so that the oil up to the cam phase adjusting means attached to the camshaft is provided. Because the path length can be set short and the phase can be adjusted with good control response, and the upper position of the camshaft is a space that is not originally used because only one side of the rocker arm is in contact with it. It is not necessary to secure a space particularly for installing the hydraulic oil control means, and it is possible to prevent the cylinder head portion from being enlarged.

[Brief description of the drawings]

FIG. 1 shows a cylinder head according to a first embodiment of FIG.
It is an I line sectional view.

FIG. 2 is a cross-sectional view showing an actuator unit.

FIG. 3 is a plan view of a cylinder head.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a sectional view taken along line VV of FIG. 3;

FIG. 6 is a sectional view showing details of an OCV.

FIG. 7 shows a cylinder head according to a second embodiment, VI in FIG. 8;
It is an I-VII line sectional view.

FIG. 8 is a plan view of a cylinder head.

[Explanation of symbols]

1,104 Camshaft 4,101 Cylinder head 9 Actuator (cam phase adjusting means) 16,102 Intake side rocker arm 17,103 Exhaust side rocker arm 19,109 Intake valve 20,110 Exhaust valve 21,115 OCV (Hydraulic oil) Control means) 46 Rocker cover

Claims (1)

[Claims] 1. A camshaft provided on a cylinder head and driven to rotate by a crankshaft, one side of which is brought into contact with the camshaft, and an intake valve and an exhaust are provided as the camshaft rotates. A rocker arm that opens and closes a valve; cam phase adjustment means attached to the camshaft and capable of adjusting the phase of the camshaft with respect to the crankshaft by hydraulic pressure of hydraulic oil; and an axis of the camshaft at a position above the camshaft. And a hydraulic oil control means for switching control of hydraulic oil from hydraulic oil supply means and supplying the control oil to the cam phase adjusting means.