JP2000240418A - Valve system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the rigidity of a rocker arm while avoiding the enlargement in size by protrusively providing, on a rocking support part, a lower connecting wall for mutually connecting the base end lower parts of a pair of support wall parts opposed with a space, to which the base end of the rocker arm is integrally molded, so as to be opposite to the lower outer circumferential surface of a roller. SOLUTION: A drive rocker arm 19 in an intake-side valve system 17I comprises a support part 19a rockably supported by a rocker shaft 22, a pair of support wall parts 311 having base ends continuously provided on the part 19a, and a tip connection part 19b for mutually connecting the tips of the support wall parts 311, which are integrally molded. A lower connecting wall 85 for mutually connecting base end lower parts of the support wall parts 311 is protrusively provided on the rocking support part 19a of the drive rocker arm 19 so as to be adjacent and opposite to the lower outer circumference of a roller 28 cooperating with a valve system cam 25 on a camshaft 18. The space between the lower connecting wall 85 and the roller 28 is set smaller than the space between an upper connecting wall 86 and the roller 28 so as to improve the rigidity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camshaft provided with a valve operating cam and a swinging support portion which is swingably supported by a support member provided on a cylinder head. A rocker arm in which the base ends of a pair of support walls facing each other at a distance in the direction along the axis are integrally connected, a support shaft supported between the support walls, and the support via a bearing. The present invention relates to a valve operating device for an internal combustion engine, comprising: a roller rotatably supported on a shaft and rollingly contacting the valve operating cam.

[0002]

2. Description of the Related Art Conventionally, such a valve train is disclosed in
It is already known in US Pat.

[0003]

The rocker arm in the above-described conventional valve operating device includes a swing support portion that is swingably supported by a pivot as a support member, and a pair of bases connected to the swing support portion. Of the support wall portion and a tip connection portion connecting between the tips of the support wall portions. The engine valve is interlocked and connected to the tip connection portion, and the support shaft is supported between the support wall portions. A roller that is in rolling contact with the valve cam is rotatably supported. However, the surface of the swing support portion facing the roller is formed as a flat surface along a plane that intersects a straight line connecting the swing fulcrum by the pivot of the swing support portion and the rotation axis of the roller. It is hard to say that the rigidity is excellent, and it is desired to further increase the rigidity of the rocker arm. Moreover, it is desirable to avoid increasing the size of the rocker arm when increasing the rigidity of the rocker arm.

The present invention has been made in view of such circumstances, and has as its object to provide a valve train for an internal combustion engine in which the rigidity of a rocker arm is increased while avoiding an increase in size.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a camshaft provided with a valve operating cam and a supporting member provided on a cylinder head are swingably supported. A rocker arm in which the base ends of a pair of support walls facing the swing support at intervals in the direction along the swing axis of the swing support are integrally connected; And a roller rotatably supported by the support shaft via a bearing and in rolling contact with the valve cam. A lower connecting wall connecting between the lower end and the lower end is projected from the swing support portion so as to face a lower outer peripheral surface of the roller.

According to such a configuration, since the base ends of the pair of support walls are connected by the lower connecting wall, the support rigidity of the support shaft by the two support walls is increased, and the rigidity of the entire rocker arm is also increased. Will do. Moreover, since the lower connecting wall is opposed to and close to the lower portion of the roller, it is also possible to temporarily hold the oil between the lower connecting wall and the roller, and to transfer the oil held between the lower connecting wall and the roller to the roller and the spindle. It is also possible to reduce the rotational resistance of the roller by guiding to the bearing between them. Moreover, the lower connecting wall is
The space between the roller and the swing support portion is effectively utilized, and the rocker arm is not enlarged by the lower connecting wall.

[0007] The invention according to claim 2 provides the above-described claim 1.
In addition to the configuration of the invention described above, the rocker arm is formed by metal injection molding. According to this configuration, the rocker arm having a relatively complicated structure in which the lower connecting wall projects from the swing support portion can be easily manufactured. Can be formed into
A rocker arm having an optimal shape in consideration of an increase in rigidity and a reduction in weight can be easily formed.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the pressing means for urging the rocker arm in a direction in which the roller is brought into rolling contact with the valve cam is provided. According to such a configuration, it is characterized by being connected to one end of the lower connecting wall along the axial direction of the support shaft and abutting on a receiving portion protruding from one lower portion of the two supporting wall portions. The rigidity of the receiving portion on which a load acts can be increased by the lower connecting wall.

According to a fourth aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the rocker arm swings at a portion opposed to the spark plug insertion cylinder attached to the cylinder head. A notch recessed on the opposite side to the spark plug insertion tube is provided in the dynamic support portion, and at least a part of the lower connecting wall and at least a part of the notch are orthogonal to the rocking axis of the rocker arm. Are arranged on the same plane.

According to the configuration of the invention described in claim 4, the spark plug insertion cylinder and the rocker arm can be arranged as close as possible, and are formed in the internal combustion engine so as to accommodate the valve gear. This can contribute to downsizing of the valve operating chamber and weight reduction of the rocker arm. Moreover, it is possible to compensate for the lowering of the rigidity of the swing support portion due to the provision of the notch by the lower connecting wall.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

FIGS. 1 to 13 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view showing a part of a valve train, and is a sectional view taken along line 1-1 in FIG. Is a plan view taken in the direction of arrow 2 in FIG.
3 is a sectional view taken along line 3-3 in FIG. 2, FIG. 4 is a sectional view taken along line 4-4 in FIG. 3, FIG. 5 is an enlarged sectional view taken along line 5-5 in FIG. 2, and FIG. 7 corresponding to FIG. 5, FIG.
8 is a sectional view taken along line 7-7 of FIG. 2, FIG. 8 is a sectional view taken along line 8-8 of FIG. 4, FIG. 9 is a sectional view taken along line 9-9 of FIG.
11 is a sectional view taken along line 11-11 of FIG. 10, FIG. 12 is a plan view of the intake-side and exhaust-side valve trains, and FIG. 13 is a sectional view taken along line 13-13 of FIG.

First, referring to FIG.
The cylinder head 11 of the cylinder internal combustion engine is provided with a pair of intake valve ports 12 for each cylinder. The two intake valve ports 12 ...
Are individually opened and closed by intake valves VI as engine valves. Stems 13 of the intake valves VI are provided with guide cylinders 14 provided on the cylinder head 11, respectively.
Is slidably fitted to. A retainer 1 provided at an upper end of a stem 13 projecting upward from each guide cylinder 14.
5 and the cylinder head 11 are provided with valve springs 16 surrounding each of the stems 13.
Are biased in a direction to close the intake valve ports 12.

Referring to FIGS. 2 to 4 together, both intake valves V
An intake-side valve train 17I is connected to I and VI. The intake-side valve train 17I is connected to a camshaft 18 which is linked to and connected to a crankshaft (not shown) at a reduction ratio of 1/2. , Which are linked and connected to one of the intake valves VI.
The drive rocker arm 19, a second drive rocker arm 20 linked to and connected to the other of the two intake valves VI, and a free rocker arm 21 that can be free with respect to the two intake valves VI.
A fixed rocker shaft 22 as a support member having an axis parallel to the camshaft 18 and supporting the rocker arms 19, 20, 21 in a common and swingable manner, and interlocking of the rocker arms 19 to 21; And interlocking switching means 23 capable of switching interlocking release.

The camshaft 18 has a high-speed valve operating cam 2.
6 and low-speed valve operating cams 25, 25 arranged on both sides of the high-speed valve operating cam 26 corresponding to the intake valves VI, respectively.

The high-speed valve operating cam 26 has a cam profile for opening and closing the intake valves VI... In a high-speed operation range of the engine, and has an arc-shaped base circular portion 26a centered on the axis of the camshaft 18. And a high-order portion 26b extending radially outward from the base circle portion 26a. The low-speed valve operating cam 25 has a cam profile for opening and closing the intake valves VI in the low-speed operation range of the engine.
A base circular portion 25a formed in an arc shape centered on the axis of the camshaft 18 and a projecting amount of the camshaft 18 protruding radially outward from the base circular portion 25a are determined by a high-order portion in the high-speed valve cam 26. The upper portion 26b has a higher portion 25b which is smaller than the amount of protrusion from the base circle portion 26a and which extends from the base circle portion 25a over a central angle range narrower than that of the higher portion 26b.

The first drive rocker arm 19, the second drive rocker arm 20, and the free rocker arm 21 are arranged adjacent to each other so as to sandwich the free rocker arm 21 between the first and second drive rocker arms 19, 20, and are shared by the rocker shaft 22. It is swingably supported.

First and second drive rocker arms 19, 2
Reference numeral 0 denotes swing support portions 19a and 20a that are swingably supported by the rocker shaft 22, and first support wall portions 31 ₁ and 32 ₁ whose base ends are connected to the swing support portions 19a and 20a, respectively.
When, the first support wall 31 _1, 32 ₁ to opposed proximal and the pivot support portion 19a in a direction along the axis of the rocker shaft 22,
The second support wall portions 31 ₂ and 32 respectively connected to the 20a
_2, both supporting walls 31 forming a cross in pairs _1, 31 _2; 32
Tip connecting portions 19b, 20 for connecting the tips of ₁ , 32 ₂
b are provided integrally with each other, and the stem 13 of each of the intake valves VI.
The tappet screws 27, 27 contacting the upper end of... The free rocker arm 21 is pivotally supported by a rocker shaft 22.
When the first and support wall 33 ₁ which base is continuously provided on the pivot support portion 21a, the second in a direction along the axis of the rocker shaft 22 1
Proximal end opposite the support wall 33 ₁ is integrally provided with a ₂ second support wall portion 33 provided continuously to the swing support portion 21a.

The swing support portion 1 of the first drive rocker arm 19
Between 9a and the tip connecting portion 19b, the first and second support walls 31 _1, 31 ₂ opening 34 which is opened up and down so as to be defined on both sides with is provided, the low-speed valve operating cam 2
The first driving rocker arm 19 is arranged such that the cylindrical roller 28 that comes into rolling contact with the first driving rocker 5 is disposed in the opening 34.
It is supported rotatably. Also, the second drive rocker arm 2
0 between the swing support portion 20a and the tip connecting portion 20b.
An opening 35 which is opened up and down so as to be defined on both sides by the first and second support wall portions 32 ₁ and 32 ₂ is provided,
A cylindrical roller 29 that is in rolling contact with the low-speed valve operating cam 25 is rotatably supported by the second drive rocker arm 20 so as to be disposed in the opening 35. Further, the first and second support wall portions 3 are provided on the free rocker arm 21.
3 _1, 33 ₂ opening 36 which opens to the opposite side and up and down with the rocker shaft 22 so as to be defined on both sides is provided with a cylindrical roller 30 is the opening for rolling contact with the high-speed valve operating cam 26 It is rotatably supported by the free rocker arm 21 so as to be disposed on the portion 36.

First support wall of first drive rocker arm 19
31₁Has a bottom with a free rocker arm 21 side
First fitting hole 37₁Is parallel to the axis of the rocker shaft 22
Provided, the second support wall portion 31_TwoIn the second, open both ends
2 fitting holes 37_TwoIs the first fitting hole 37₁And coaxially installed
You. Free rocker arm in the second drive rocker arm 20
First support wall 32 on the side of the memory 21₁Open both ends
First fitting hole 38₁Is parallel to the axis of the rocker shaft 22
Provided, the second support wall portion 32_TwoFree rocker arm 2
A bottomed second fitting hole 38 having one side opened._TwoIs the first fitting hole 3
8₁And coaxially provided. Free rocker arm 21
And the first support wall 33 on the first drive rocker arm 19 side.
₁Has a first fitting hole 39 with both ends opened.₁But Rocka Shaff
The second support wall 33 is provided in parallel with the axis of the_TwoTo
Is a second fitting hole 39 having both ends opened. _TwoIs the first fitting hole 39
₁And coaxially provided.

The first fitting hole 3 of the first drive rocker arm 19
7 ₁ one end of a cylindrical support shaft 41 until it abuts is fitted at its closed end to, the second fitting hole 37 ₂ the support shaft 41
Is fitted at the other end. The second drive rocker arm 20
Of the first fitting hole 38 _1, the end of the cylindrical support shaft 42 is fitted, the other end of the support shaft 42 to the second fitting hole 38 ₂ abuts on the closed end Mated. Further, the first and second fitting holes 39 ₁ and 39 ₂ of the free rocker arm 21 are provided.
The two ends of the cylindrical support shaft 43 are fitted to the respective shafts.

[0022] Referring also to FIG. 5, the second support wall 31 ₂ of the first driving rocker arm 19, the rocker shaft 2
With 2 and second fitting hole 37 ₂ of the insertion hole 44 communicating with the second fitting hole 37 ₂ of the inner surface extending linearly in a direction intersecting the straight line connecting the axis it is provided, at the upper end of the insertion hole 44 a first recess 80 which opens to the second upper surface of the support wall portion 31 ₂ through a second recess 81 which opening is provided on the lower surface lower end through to the second support wall 31 ₂ of the insertion hole 44, The first and second concave portions 80 and 81 are formed to have a larger diameter than the insertion hole 44.

On the other hand, the outer surface of the support shaft 41 in correspondence with the opening of the insertion hole 44 into the second fitting hole 37 ₂ of the inner surface, the tangent of the virtual circle C about the axis of the support shaft 41 An engaging groove 50 extending along the direction is provided. A pin 47 extending linearly is inserted into the insertion hole 44 as shown in FIG. Engaged.

As shown in FIG. 5, both ends of the pin 47 inserted into the insertion hole 44 are caulked by flat punches 82 and 83 having outer diameters smaller than the inner diameters of the recesses 80 and 81, respectively. The swaging part 47 crushed in a disk shape
a and 47a are engaged with the steps between the concave portions 80 and 81 and the insertion hole 44, whereby the support shaft 41 is fixed to the first drive rocker arm 19.

[0025] The first support wall 32 ₁ of the second driving rocker arm 20, the support shaft 42 is fixed in the same structure as the fixing structure of the first driving rocker arm 19 of the support shaft 41. That is, the pin 48 which is inserted into the insertion hole 45 provided in the first support wall portion 32 ₁ of the second drive rocker arm 20 and which is caulked at both ends is fitted to the first fitting hole 38 ₁ . 42 is engaged with an engaging groove 51 provided on the outer surface.

Furthermore in the first support wall 33 ₁ of the free rocker arm 21, the second driving rocker arm of the first fixing structure of the driving rocker arm 19 and the support shaft 42 of the supporting shaft 41 2
The support shaft 43 is fixed by a structure similar to the structure for fixing the shaft 43 to zero.
That is, the first support wall 33 ₁ of the free rocker arm 21 ₁
Engaging the engaging groove 52 which ends with being inserted into the insertion hole 46 provided with the pins 49 to be swaged is provided on the outer surface of the support shaft 43 is fitted to the first fitting hole 39 ₁ Is done.

The depth of each of the engagement grooves 50, 51, 52 is
Pins 47 and 4 corresponding to the respective engagement grooves 50 to 52
8, 49 or less of the radius, preferably each pin 47
４９49 is set to about 半径 of the radius. By doing so, not only the processing when forming the engagement grooves 50 to 52 on the support shafts 41 to 43 becomes easy, but also the engagement grooves 50 to 52 are formed.
It is possible to prevent the rigidity of the support shafts 41 to 43 from being reduced as much as possible by the formation of.

The hardness of at least the portion of each of the pins 47 to 49 that engages with the engagement grooves 50 to 52, in this embodiment, the hardness of the portion of each of the pins 47 to 49 inserted into the insertion holes 44 to 46 is
Both ends of each of the pins 47 to 49, in this embodiment, the insertion holes 44
The hardness is set to be higher than the hardness of the protruding end portion from # 46. Each of the pins 47 to 49 is, for example, a JIS SUJ2
By subjecting the pins 47 to 49 to intermediate portions in the axial direction, for example, by induction hardening, the hardness of a part of the outer surface of each of the pins 47 to 49 is increased. Thus,
Pin least hardness of a portion which engages the engaging groove 50 to 52 induction hardening by e.g. H _V 579 of 47 to 49
832, and pins 47 to 49 which are unhardened areas.
Both end portions hardness of, for example, an H _V 180 to 260.

The roller 28 and the support shaft 41 are provided between the first and second support wall portions 31 ₁ and 31 _{2 of} the first drive rocker arm 19.
A needle bearing 53 is interposed between the first drive rocker arm 20 and the first and second support wall portions 32 ₁ , 32 ₁ , of the second drive rocker arm 20.
32 between _2, needle bearings 54 are interposed between the roller 29 and the shaft 42, between the free first and second support walls 33 _1, 33 of the rocker arm 21 _2, roller 30
A needle bearing 55 is interposed between and the support shaft 43.

In FIG. 7, a lost motion mechanism is provided below the free rocker arm 21 on the cylinder head 11 to apply a spring force to the free rocker arm 21 in the direction of rolling the roller 30 of the free rocker arm 21 into contact with the high-speed valve cam 26. The lost motion mechanism 58 is provided with a bottomed cylindrical lifter 60 that is slidably fitted into a bottomed sliding hole 59 provided in the cylinder head 11 with its upper part opened. It comprises a closed end of the moving hole 59 and a spring 61 provided between the lifter 60.

On the other hand, the free rocker arm 21 is
Lifter 60 to receive the spring force from the
Is provided with a receiving portion 62 that contacts the upper end of the
The receiving portion 62 is provided with the first and second rocker arms 21.
And the second support wall 33₁, 33 _TwoOf the first support wall 33
₁A pin 49 is inserted and fixed to fix the support shaft 43 to the
On the other hand, the second support wall 33_TwoRidge downwards at the bottom of
Raised and provided integrally.

Referring to FIGS. 1 and 5, the swing support 19a of the first drive rocker arm 19 includes first and second rockers.
A lower connecting wall 85 that connects between the base lower portions of the support wall portions 31 ₁ and 31 ₂ protrudes so as to approach and oppose the lower outer peripheral surface of the roller 28, and the first and second support wall portions 31. _1, 31 upper connecting wall 86 for connecting the _two proximal upper
Is protruded so as to approach and face the upper outer peripheral surface of the roller 28, and the interval between the lower connecting wall 85 and the roller 28 is set smaller than the interval between the upper connecting wall 86 and the roller 28.

Further, the lower connecting wall 85 connects the support shaft 41 to the first
It is connected to the lower portion of the second support wall 31 ₂ in a position corresponding to the second recess 81 for accommodating by crimping the lower end of the pin 47 for securing to the drive rocker arm 19. In addition, the swing support portion 19 is provided between the lower connecting wall 85 and the upper connecting wall 86.
The surface a facing the roller 28 is formed in a curved shape corresponding to the outer peripheral surface of the roller 28.

The surface of the distal end connecting portion 19b facing the roller 28 has a curved surface corresponding to the outer peripheral surface of the roller 28, and is formed so that the distance from the roller 28 becomes smaller as it goes downward. Thereby, in the portion corresponding to the lower half of the tappet screw 27 in the axial direction, the thickness of the distal end connecting portion 19b in the direction orthogonal to the axis of the tappet screw 27 corresponds to the upper half of the tappet screw 27 in the axial direction. Is larger than the above thickness.

The surface of the second drive rocker arm 20 that faces the roller 29 of the swing support portion 20a and the surface of the tip connecting portion 20b that faces the roller 29 correspond to the swing support portion 19a and the tip of the first drive rocker arm 19. It is formed similarly to the connecting portion 19b.

Referring to FIG. 7, the first and second support wall portions 3 are provided on the swing support portion 21a of the free rocker arm 21.
3 _1, 33 ₂ of the adjacent lower connecting wall 87 for connecting the base end lower portion in the lower outer peripheral surface of the roller 30, while being projected so as to face the first and second support walls 33 _1, 3
3 upper connecting wall 88 for connecting the _two proximal upper roller 3
The upper connecting wall 87 and the roller 30 are set smaller than the gap between the upper connecting wall 88 and the roller 30.

[0037] Moreover the lower connecting wall 87, the support shaft 43 a free pin 47 for fixing the rocker arm 21 the lower end of the second recess 81 first at a position corresponding to the support wall 33 ₁ for accommodating caulking while being connected to the lower, first at the portion corresponding to the receiving portion 62 which is protruded from the lower portion of the lost motion mechanism second in order to contact the 58 support wall 33 ₂ 2
It is connected to the support wall 33 _2. The surface of the swing support portion 21 a facing the roller 30 between the lower connecting wall 87 and the upper connecting wall 88 is formed in a curved shape corresponding to the outer peripheral surface of the roller 30.

The interlocking switching means 23 is connected to the first
Timing piston 63 capable of switching between interlocking and uncoupling of drive rocker arm 19 and free rocker arm 21
A cylindrical switching piston 64 capable of switching between interlocking and uncoupling of the free rocker arm 21 and the second drive rocker arm 20 adjacent to each other;
A regulating member 65 having a cylindrical shape with a bottom and coming into contact with the switching piston 64 on the opposite side; and a return spring 66 for urging the regulating member 65 toward the switching piston 64.

The timing piston 63 is slidably fitted to the support shaft 41 of the first drive rocker arm 19, and has a first fitting hole 37 ₁ into which one end of the support shaft 41 is fitted.
A hydraulic chamber 67 is defined between the closed end of the piston and one end of the timing piston 63. An oil passage 68 connected to a hydraulic pressure source via a control valve (not shown) is provided, for example, coaxially in the rocker shaft 22, and a first support wall of the first drive rocker arm 19 is passed through one end of the hydraulic chamber 67. Part 33 ₁
A communication hole 69 is provided in the rocker shaft 22 so that the communication passage 70 provided in the rocker shaft 22 always communicates with the oil passage 68.

Referring to FIG. 8 as well, the communication path 70 is arranged in the direction in which the rocker arms 19 to 21 are arranged, that is, in this embodiment, in the direction in which the rocker arms 19 to 21 are arranged in the direction along the axis of the rocker shaft 22. Each rocker arm 1 has a cross-sectional shape with a length in a direction orthogonal to
The first drive rocker arm 19 is provided on the first support wall portion 31 ₁ side so as to extend along a plane substantially orthogonal to the arrangement direction of 9 to 21, regardless of the swing state of the first drive rocker arm 19. The communication passage 70 is connected to the rocker shaft 22 so that the oil passage 68 always communicates with the communication passage 70.
A communication hole 69 is provided in the rocker shaft 22 in a range larger in the circumferential direction of the rocker shaft 22 than in a range facing the outer surface of the rocker shaft 22. In addition, the other end of the communication passage 70 opens to the side of the first drive rocker arm 19, and the intermediate portion of the communication passage 70 is blocked by the rocker shaft 22.

Referring to FIG. 9 as well, in the first drive rocker arm 19, a bulging portion 19c bulging outward to form the communication passage 70 is formed on the outer surface on one end side in the arrangement direction of the rocker arms 19 to 21. Are provided between the side edge 19d of the outer surface of the first drive rocker arm 19 and the bulging portion 19c.
71 are provided.

By the way, the communication passage 70 has a part thereof parallel to the axis of the rocker shaft 22 in the direction of the support shaft 41.
So that it is located closer to the roller 28 than one end of the first
The drive rocker arm 19 is provided with a notch 72 having a shape corresponding to the communication passage 70 at a portion corresponding to the communication passage 70 at one end of the support shaft 41.
That is, the hydraulic oil flowing through the communication passage 70 is guided to the hydraulic chamber 67 without being interrupted by the support shaft 41.

The switching piston 64 is connected to the free rocker arm 21.
And one end of the switching piston 64 is brought into contact with the other end of the timing piston 63 so as to be able to slide on each other.

The restricting member 65 is formed in a cylindrical shape with a bottom and is slidably fitted to the support shaft 42 of the second drive rocker arm 20. The other ends are allowed to contact each other, allowing them to slide. A retaining ring 73 is mounted on the inner surface of the support shaft 42 so as to contact the control member 65 and prevent the control member 65 from dropping off the support shaft 42. Return spring 66
Is a second fitting hole 38 in the second drive rocker arm 20.
₂ between the closed end of the _second and the regulating member 65,
The closed end of the fitting hole 38 ₂ open pores 74 are drilled.

In the interlocking switching means 23, in the low-speed operation range of the engine, the hydraulic pressure in the hydraulic chamber 67 is relatively low, and the timing piston 63 and the switching piston 64
Is located at a position corresponding to between the first drive rocker arm 19 and the free rocker arm 21, and the switching piston 64
The contact surface of the regulating member 65 is located at a position corresponding to between the free rocker arm 21 and the second drive rocker arm 20. Therefore, each rocker arm 19, 20, 21 is in a state in which it can relatively swing, and both intake valves VI are driven to open and close at a timing and a lift amount corresponding to the low-speed valve cams 25, 25.

In the high-speed operation range of the engine, a relatively high hydraulic pressure is applied to the hydraulic chamber 67 so that the timing piston 6
3 is fitted to the support shaft 43 of the free rocker arm 21 while pressing the switching piston 64, and the switching piston 64 presses the regulating member 65 while supporting the support shaft 4 of the second drive rocker arm 20.
2 is fitted. Therefore, each rocker arm 19, 20,
21 are connected integrally, and the two intake valves VI ...
Is driven to open and close at a timing and a lift amount corresponding to the high-speed valve operating cam 26.

[0047] Referring also to FIGS. 10 and 11, two support walls 33 _1, 33 side receiving portion 62 of the _two is provided in the free rocker arm 21, i.e. the second support wall portions 33
The _2, provided so as lubricating oil passage 76 communicating at all times to the oil passage 68 of the rocker shaft 22 is opened to one end to the second fitting hole 39 ₂ of the inner surface, the second fitting hole 39 ₂ of the inner surface Is provided with a groove 77 having one end connected to one end of the lubricating oil passage 76 and the other end opened to the bearing 55 side.

Further, the lubricating oil passage 76 has a cross section having a length in a direction substantially perpendicular to the arrangement direction of the rocker arms 19 to 21 longer than a length in a direction substantially parallel to the arrangement direction of the rocker arms 19 to 21. The lubricating oil passage 76 is formed so as to be always in communication with the lubricating oil passage 76 regardless of the swinging state of the free rocker arm 21. A communication hole 78 is provided in the rocker shaft 22 in a large range in the circumferential direction of the shaft 22. The other end of the lubricating oil passage 76 is open to the side of the free rocker arm 21, and an intermediate portion of the lubricating oil passage 76 is blocked by the rocker shaft 22.

The rocker arms 19, 2
Reference numerals 0 and 21 are formed by metal injection molding. Thus, in performing metal injection molding, a step of kneading a binder such as a raw material powder and a wax, a step of granulating the compound obtained in the kneading step to obtain a pellet, and injecting the pellet in a mold Molding and shaping, heating the shaped product to remove the binder,
The steps of performing the sintering process may be sequentially performed.

In FIGS. 12 and 13, the cylinder head 11 faces the center of the combustion chamber 90 of each cylinder.
A mounting hole 92 for mounting the ignition plug 91 is provided in the cylinder head 11, and a spark plug insertion cylinder 93 extending upward through the mounting hole 92 is mounted on the cylinder head 11. Can be

Above the cylinder head 11, an intake-side valve operating device 17 for opening and closing the pair of intake valves VI, VI is provided.
I and an exhaust-side valve operating device 17E for driving the pair of exhaust valves VE, VE to open and close are disposed so as to sandwich the spark plug insertion cylinder 93 therebetween. Moreover, the exhaust side valve train 1
7E has the same configuration as the intake-side valve operating device 17I.
Corresponding portions of 7I and the exhaust-side valve train 17E are denoted by the same reference numerals, and are only shown in the drawings, and detailed description of the exhaust-side valve train 17E is omitted.

The ignition plug insertion cylinder 93 is disposed between the free rocker arms 21 and 21 of the intake-side valve operating device 17I and the exhaust-side valve operating device 17E, respectively.
A notch 94 that is recessed on the opposite side of the ignition plug insertion tube 93 is provided in a portion of the swing support portion 21a of the free rocker arms 21 that faces the ignition plug insertion tube 93.

The notch 94 is formed so as to be curved corresponding to the outer peripheral surface of the ignition plug insertion cylinder 93 having a circular cross section. The radius of curvature of the notch 94 is equal to that of the outer surface of the ignition plug insertion cylinder 93. It is set larger than the radius. Further, the notch 94 is provided at the center of the swing support portion 21 a in the direction along the axis of the rocker shaft 22, and the deepest portion of the notch 94 (the center of the ignition plug insertion cylinder 93) and the free rocker arm 21 A part of the roller 30 (preferably, the axial center of the roller 30 as in this embodiment) is disposed on the same plane orthogonal to the rotation axis of the free rocker arm 21, that is, the axis of the rocker shaft 22. You.

The notch 94 is provided in the opening 3 provided in the free rocker arm 21 for accommodating the roller 30.
6, that is, the first in the free rocker arm 21.
And a portion corresponding to the portion between the second support wall portions 33 ₁ and 33 ₂ , provided on the swing support portion 21 a, and cutouts 94 at both ends of the swing support portion 21 a along the axis of the rocker shaft 22. Arc-shaped bulging portions 95, 95 bulging outward so as to be sandwiched between them are formed.

The second support wall 33 of the free rocker arm 21
The _second, although the lubricating oil passage 76 communicating at all times to the oil passage 68 of the rocker shaft 22 is provided so as to open the one end to the second fitting hole 39 ₂ of the inner surface, the other of the lubricating oil passage 76 The end is open to the outer surface of one of the bulges 95, 95 so as to be located at a position off the notch 94 along the axis of the rocker shaft 22.

[0056] Furthermore the free rocker arm two support walls 33 ₁ of 21, 33 ₂ of the base end between the lower portion while being connected at the lower connecting wall 87, two support walls 33 _1, 33 ₂ of the base end between the upper upper connecting Although connected by a wall 88, at least a part (all in this embodiment) of the notch 94 and at least a part of the lower connecting wall 87 (in this embodiment, the center of the lower and upper connecting walls 87, 88). Part) is the swing axis of the free rocker arm 21, that is, the rocker shaft 22.
Are arranged on the same plane that is orthogonal to the axis.

Vertically extending grooves are provided on the outer surface of the free rocker arm 21 near the swing support portion 21a of the two support wall portions 33 ₁ and 332, and these grooves are used to extend the adjacent _first and _second rocker arms. The first drive rocker arm 19 and the free rocker arm 21 and the second
Between the drive rocker arm 20 and the free rocker arm 21, oil grooves 96, 96 having upper ends opened at the upper portions of the respective rocker arms 19 to 21, are formed.

Next, the operation of this embodiment will be described. Each of the rocker arms 19 to 21 has a support shaft 41 to rotatably support rollers 28 to 30 for reducing a valve operating load.
43 is fixed, but both end portions of each of the support shafts 41 to 43 are provided with first fitting holes 37 ₁ , 3 provided in each of the rocker arms 19 to 21.
8 _1, 39 ₁ and second fitting holes 37 _2, 38 _2, 39 ₂
Respectively. Also, the first drive rocker arm 19
The second support wall 31 ₂ pin 47 which is inserted into the insertion hole 44 provided in the is engaged with the engaging groove 50 of the support shaft 41, the second
Pin 48 which is inserted into the insertion hole 45 provided in the first support wall 32 ₁ of the driving rocker arm 20 is engaged with the engaging groove 51 of the support shaft 42, the first support wall 33 ₁ of the free rocker arm 21 The pins 49 inserted into the insertion holes 46 provided are engaged with the engagement grooves 52 of the support shafts 43 to prevent the support shafts 41 to 43 from moving in the axial direction and rotating around the axes. Therefore, the support shafts 41 to 43 can be fixed to the rocker arms 19 to 21 with a simple structure.

Each of the pins 47 to 49 is connected to the corresponding rocker arm 1.
In fixing to 9 to 21, both ends of each of the pins 47 to 49 inserted into the insertion holes 44 to 46 are caulked, so even if each of the pins 47 to 49 has a small diameter,
The fixing work is easier than the press-fitting, the workability is improved, and the pins 47 to 49 can be securely fixed to the rocker arms 19 to 21.

Further, the pins 47 to 49 are not press-fitted but are inserted into the insertion holes 44 to 46. The inner diameter of each of the insertion holes 44 to 46 is smaller than the outer diameter of each of the pins 47 to 49. The width of each of the engagement grooves 50 to 52 may be set to have a relatively large margin with respect to the diameter of each of the pins 47 to 49. Then, each pin 47-49 can be inserted into each of the insertion holes 44-49 without strictly setting the circumferential position of each support shaft 41-43.
46, it is easy to engage with each of the engagement grooves 50 to 52, and each of the rocker arms 19 to 2 of each of the pins 47 to 49.
1 can be easily fixed.

Both ends of each of the pins 47 to 49 are flat punches 8.
Since the diameters of the flat punches 82 and 83 are set larger than the diameters of the pins 47 to 49, even if the positions of the flat punches 82 and 83 with respect to the pins 47 to 49 are slightly shifted. The pins 47 to 49 can be securely caulked, and the rigidity of the caulked portion does not decrease due to the displacement of the caulking position. Moreover, the insertion holes 44 to 46
, And flat punches 82, 8 in recesses 80, 81.
Are set larger than the outer diameters of the flat punches 82, 83 so as to be able to accommodate
By crimping both ends of the pins 47 to 49 in the concave portions 80, 81, the caulked portion does not protrude from the outer surfaces of the rocker arms 19 to 21, and furthermore, the concave portions 80, 81
Are provided, the insertion holes 44 to 46, that is, the pins 4 are provided.
It is possible to shorten the length of 7 to 49, prevent deformation of the intermediate portion of the pins 47 to 49 by caulking as much as possible, and improve the positioning accuracy of the shafts 41 to 43 by the pins 47 to 49. And rocker arm 1
Rocker arms 19-21 to reduce overall weight
, The inertial weight of the internal combustion engine can be reduced, and it is possible to advantageously cope with high-speed rotation of the internal combustion engine.

[0062] By further portion which engages at least the engaging groove 50 to 52 of the pin 47 to 49 is relatively high hardness (induction hardening region) (e.g. H _V 579~832), the pins 47-49 Wear Shaft 4 to prevent deformation and
1 to 43 can be reliably positioned, and the pins 47 to 4
9 will be improved caulking accuracy becomes easy crimping the end portions is relatively low hardness (not quenched region) (e.g. H _V 180 to 260) that the.

The first drive rocker arm 19 has an oil passage 68 of the rocker shaft 22 and a hydraulic chamber 67 of the interlocking switching means 23.
Is provided so as to extend in a plane substantially orthogonal to the arrangement direction of the rocker arms 19 to 21. The communication passage 70 is provided with the rocker arms 19 to 21.
Has a cross-sectional shape in which the length in a direction substantially perpendicular to the arrangement direction of the rocker arms 19 to 21 is larger than the length in a direction substantially parallel to the arrangement direction. Therefore, the communication path 7 is parallel to the direction in which the rocker arms 19 to 21 are arranged.
The space occupied by 0 can be reduced as much as possible, and the first drive rocker arm 19 can be reduced in size accordingly.

In addition, the first drive rocker arm 19
One end of the shaft 41 is connected to the first support wall 31. ₁First fitting hole 37
₁To the first drive rocker arm 1
9, the communication path 70 is the first supporting path.
Wall 31₁Side is provided on the first drive rocker arm 19
Thereby, the support shaft 41 supporting the roller 28 is fixed.
Support wall portion 31 for₁Avoid increasing the thickness of the
The communication passage 70 in the first drive rocker arm 19.
And it is possible. Moreover, the link at one end of the support shaft 41 is
A portion corresponding to the passage 70 has a shape corresponding to the communication passage 70
Is provided, the first drive rocker arm
First support wall portion 31 provided in 19₁First fitting hole 37₁When
The contact area of the support shaft 41 is sufficiently secured and the first
Communicates while securing the support strength to the drive rocker arm 19
The path 70 can be arranged closer to the roller 28 side.
It is possible to move the first drive rocker arm 19
Size can be reduced.

As described above, since the first drive rocker arm 19 can be reduced in size, in the multi-cylinder internal combustion engine as in this embodiment, the cylinder head 11 can be significantly reduced in size.

A communication passage 7 is provided on the outer surface on one end side of the first drive rocker arm 19 along the axial direction of the rocker shaft 22.
0, a bulging portion 19c bulging outward is provided, and ribs 71, 71 connecting the side edge portion 19d of the outer surface and the bulging portion 19 are provided, so that the bulging portion forming the communication passage 70 is provided. It is possible to reduce the weight of the first drive rocker arm 19 while securing the rigidity of the first drive rocker arm 19.

Further, the communication path 70 is provided on the first support wall 31 ₁ side of the first drive rocker arm 19,
The roller 28 in the second support wall 31 ₂ sandwiched between the first support wall 31 _1, since the insertion holes 44 for fixing the support shaft 41 is provided, avoiding an increase in size of the first driving rocker arm 19 As a result, the space for providing the insertion hole 44 can be secured, and the provision of the insertion hole 44 at a position relatively far from the communication passage 70, which is a cavity, is advantageous in terms of the rigidity of the first drive rocker arm 19.

In the free rocker arm 21, the second fitting hole 3
A lubricating oil passage 76 is provided at the inner surface of the _second opening 92 at one end thereof and communicates with the oil passage 68 of the rocker shaft 22.
9 ₂ of the inner surface, the groove 77 was allowed open at the other end to the needle bearing 55 side together providing communication at one end thereof to one end of the lubricating oil passage 76 is provided, via the lubricating oil passage 76 and the groove 77 from the oil passage 68 needle bearing Te lubricating oil would be oil to the needle bearing 55, a simple structure of only grooves 77 in the second fitting hole 39 ₂ of the inner surface with the lubricating oil passage 76 is provided is provided in the free rocker arm 21 55 can be refueled. Therefore, it is not necessary to perform a drilling process for guiding the lubricating oil to the support shaft 43, and there is no possibility that the rigidity of the support shaft 43 is reduced, and the number of processing steps is reduced.

The free rocker arm 21 is driven by the high-speed valve cam 26 having a cam profile for high-speed operation of the engine, and has a relatively large inertial weight and a relatively large load on the needle bearing 55. However, the needle bearing 55 has a simple structure as described above.
Lubricating oil can be supplied effectively, and the load acting on the needle bearing 55 can be reduced.

Further, the lubricating oil passage 76 has a cross-sectional shape in which the length in the direction substantially perpendicular to the arrangement direction of the rocker arms 19 to 21 is longer than the length in the direction substantially parallel to the arrangement direction of the rocker arms 19 to 21. The space occupied by the lubricating oil passage 76 can be reduced as much as possible in a direction parallel to the arrangement direction of the rocker arms 19 to 21, and the free rocker arm 21 can be reduced in size. Accordingly, the size of the cylinder head 11 of the multi-cylinder internal combustion engine can be reduced.

[0071] Also in the free rocker arm 21, the lubricating oil passage 76 is an insertion hole 46 for fixing the support shaft 43 with respect to the provided second support wall 33 ₂ side first support wall portion 33
Since it is provided on _one side, it is possible to secure a space for providing the insertion hole 46 while avoiding an increase in the size of the free rocker arm 21, and to insert the insertion hole 44 at a position relatively far from the lubricating oil passage 76 which is a cavity. Since it is provided, the rigidity of the free rocker arm 21 is also advantageous.

The free rocker arm 21 has a receiving portion 62 that comes into contact with the lifter 60 of the lost motion mechanism 58. The receiving portion 62 is provided with the second support wall 33 _2.
The rocker arm 21 is provided integrally with the lower portion of the free rocker arm 21 so that the receiving portion 62 is arranged beside the roller 30.
Can be simplified, the size of the free rocker arm 21 can be prevented from being increased, and the inertial weight of the free rocker arm 21 can be reduced to advantageously cope with high-speed rotation of the internal combustion engine.

Further, the support shaft 43 is connected to the first support wall 33.₁By the side
While the receiving portion 62 is fixed by the pin 49,
Support wall 33_TwoThe pin 49 is inserted and fixed.
The size and arrangement of the insertion hole 46 for
Therefore, it is not limited and lost motion machine
The load from the frame 58 is less likely to act on the pin 49, and
Can be increased in fixing strength. In addition,
The bracket 62 is the second support wall 33_TwoWill be provided integrally with
Thus, the hollow lubricating oil passage 76 is _TwoSet in
Despite being cut, the second support wall 33_TwoTsuyoshi
It is possible to avoid a decrease in lubricity, and at the same time,
Support wall 33 due to the fact that is hollow_TwoWeight loss
The supporting wall portions 3
3₁, 33_TwoThe weight balance can be good
You.

Further, the free rocker arm 21 is
3 inserted first support wall 33 with a hole 46 is provided ₁ for fixing the can is supported on the rocker shaft 22 so as to be disposed side first driving rocker arm 19, the second driving rocker arm 20, the support shaft 42 Insertion hole 45 for fixing
Is provided on the rocker shaft 22 such that the first support wall portion 32 ₁ is disposed on the first drive rocker arm 19 side, and the timing piston 63 and the switching piston 64 of the interlock switching means 23 are inserted. The support shafts 43 and 42 are fixed to the free rocker arm 21 and the second drive rocker arm 20 on the side of
64 is smoothly inserted into the support shafts 43 and 42, and the interlocking switching operation of the interlocking switching means 23 is smoothed.

By the way, each of the rocker arms 19 to 21
And those formed by metal injection molding, it is possible to form the communication passage 70, both the fitting holes 37 _1, 37 ₂ and the insertion hole 44 is not a perfect circle at the same time as the formation of the first driving rocker arm 19, the second At the same time when the drive rocker arm 20 is formed, the two fitting holes 38 ₁ and 38 ₂ , the insertion hole 45 and the open hole 74 can be formed. Holes 39 ₁ , 39 ₂
And the insertion hole 46 can be formed. Therefore, the post-processing of each of the rocker arms 19 to 21 can be minimized to improve the productivity.

In each of the rocker arms 19 to 21,
The rocker arms 19 to 21 are provided on the rocking support portions 19 a to 21 a which are rockably supported by the rocker shaft 22.
A pair of support wall portions 31 ₁ , 31 ₂ ; 32 ₁ , 32
₂ ; the roller 28 is connected by connecting the lower portions of the base ends of 33 ₁ and 33 _2.
Lower connecting wall 85 close to and facing the lower outer peripheral surface of
, 87 are projected, and the support wall portions 31 ₁ , 31
_2; 32 _1, 32 _2; 33 _1, 33 near the _inter-2 of the base end upper on the upper outer peripheral surface of the linked rollers 28-30, upper connecting wall 86 facing ..., since 88 is projected, a lower The surfaces of the swing support portions 19a to 21a facing the rollers 28 to 30 are formed in a curved shape between the connection walls 85 ... 87 and the upper connection walls 86 ..., 88, and thus both support wall portions 3 are formed.
1 _1, 31 _2; 32 _1, 32 _2; 33 _1, 33 ₂ rocker arm 19-21 can increase the rigidity of the entire it becomes possible to increase the supporting rigidity of the support shaft 41 to 43 by the rigidity increases Weight increase due to the curved surface can be avoided as much as possible.

The lower connecting walls 85 and 87 and the upper connecting walls 86 and 88 are arranged by effectively utilizing the space between the rollers 28 to 30 and the swing support portions 19a to 21a. The rockers 19 to 21 are not enlarged by the walls 85... 87 and the upper connecting walls 86.

The lower connecting walls 85...
30 and the lower connecting wall 85
..., oil is temporarily held between 87 and rollers 28-30
And the lower connecting walls 85 ... 87 and
The oil held between the rollers 28 and 30 is
30 and needle bearing 53 between support shafts 41 to 43
To 55 to reduce the rotational resistance of the rollers 28 to 30
It is also possible. At this time, the lower connecting walls 85 ... 87
And the gap between the rollers 28 and 30 is the upper connecting wall 86.
Set smaller than the distance between 88 and rollers 28-30
So that oil from above can be
..., effectively leading between 87 and rollers 28-30
Can be. It is arranged above the support shafts 41 to 43.
The hit load received from the valve operating cams 25.
The lower part is larger than the upper part of ~ 43.
The lower connecting wall 8 having a larger protrusion amount than the connecting walls 86.
5, 87 support the lower portions of the support shafts 41 to 43.
Support wall 31₁, 31_Two; 32 ₁, 32_Two33₁, 3
3_TwoOf each support wall 31₁, 3
1_Two; 32₁, 32_Two33₁, 33_TwoGood for improving rigidity of
It is profitable.

Further, the first and second drive rocker arms 1
In FIGS. 9 and 20, the surface of the distal end connecting portions 19b and 20b facing the rollers 28 and 29 has a curved shape corresponding to the outer peripheral surface of the rollers 28 and 29, and the roller 2 moves downward.
Since it is formed so that the interval between 8, 29 is small,
The oil is also effectively held in the lower portion between the rollers 28, 29 and the tip connecting portions 19b, 20b, and the rollers 28, 29
Rotation resistance can be further reduced,
It is possible to increase the thickness of the tip connecting portion 19b in a direction perpendicular to the axis of the tappet screw 27 at a portion corresponding to the lower half in the axial direction of the tappet screw 27 to increase the support rigidity of the tappet screw 27. it can.

Further, since each rocker arm 19-21 is formed by injection molding of metal, the lower connecting walls 85, 87 and the upper connecting walls 86, 88 project from the swing support portions 19a-21a. A complicated structure can be easily formed, and rocker arms 19a to 21a having optimum shapes in consideration of an increase in rigidity and a reduction in weight can be easily formed.

Further, each rocker arm 19 to 21 is smelled.
Of the pins 47 to 49 for fixing the support shafts 41 to 43
The second concave portions 81 facing the lower end are provided with lower connecting walls 85.
The supporting wall portion 31 corresponds to a portion corresponding to the connection portion with the connecting portion 87._Two, 32
₁, 33₁Of the second concave portion 81.
Is provided so that the support wall portion 31 is provided._Two, 32₁, 33
₁Can be suppressed as much as possible.

On the other hand, it comes into contact with the lost motion mechanism 58.
Receiving portion provided on the free rocker arm 21 as described above
62 is a second supporting wall portion connected to one end of the lower connecting wall 87.
33 _TwoThe lost motion mechanism 58
The rigidity of the receiving part 62 to which the load acts acts on the lower connecting wall 87
Therefore, it can be increased.

The swing support portions 21 of the free rocker arms 21.
a in the portion facing the spark plug insertion cylinder 93,
A notch 94 is provided on the side opposite to the spark plug insertion tube 93. Therefore, the spark plug insertion cylinder 93 and the free rocker arm 21 can be arranged as close to each other as possible, and the valve operating chamber formed in the internal combustion engine to accommodate the intake and exhaust side valve operating devices 17I and 17E can be reduced in size. In addition, it is possible to contribute to weight reduction of the free rocker arm 21. In addition, at least a part of the notch 94 (all in this embodiment) and at least a part of the lower connecting wall 87 (the center of the lower and upper connecting walls 87, 88 in this embodiment) are aligned with the axis of the rocker shaft 22. The lower connecting wall 87 and the upper connecting wall 88 make it possible to compensate for the reduction in rigidity of the swinging support portion 21a due to the provision of the notch 94 because they are arranged on the same plane orthogonal to each other.

The notch 94 is formed so as to be curved in accordance with the outer peripheral surface of the spark plug insertion cylinder 93 having a circular cross section, so that the rigidity of the free rocker arm 21 is prevented as much as possible while the free rocker arm 21 is prevented. Can be brought closer to the spark plug insertion tube 93. Moreover, since the radius of curvature of the notch 94 is set to be larger than the radius of the outer surface of the spark plug insertion tube 93, the free rocker arm 21 is ignited while avoiding mutual interference between the swinging free rocker arm 21 and the spark plug insertion tube 93. Plug insertion tube 93
And the lowering of the rigidity of the free rocker arm 21 due to the formation of the notch 94 can be suppressed.

The deepest part of the notch 94 and a part of the roller 30 supported by the free rocker arm 21 (preferably, the axial center of the roller 30 as in this embodiment) are orthogonal to the axis of the rocker shaft 22. Free rocker arm 2 for receiving the roller 30
1 within the width of the opening 36 provided in the swing support portion 21.
a is provided with a notch 94, so that the load from the intake valve VI or the exhaust valve VE and the high-speed valve cam 2
The notch 94 is arranged at a position deviated from the portion where the load from the load 6 acts on the free rocker arm 21, and even if the rigidity of the free rocker arm 21 is reduced by the formation of the notch 94, the entire free rocker arm 21 As a result, sufficient rigidity can be maintained.

Also, arc-shaped bulges 95, 95 bulging outward are formed at both ends of the rocking support 21 a along the axis of the rocker shaft 22 so as to sandwich the notch 94 therebetween. The swelling portion 9 reduces rigidity reduction due to the notch 94.
The support walls 33 ₁ , 33 _{2 on which} the load from the intake valve VI or the exhaust valve VE and the load from the high-speed valve cam 26 act the most can be used.
Can be increased by the bulging portions 95, 95.

A lubricating oil passage 76 which always communicates with the oil passage 68 of the rocker shaft 22 is opened on the outer surface of the swing support portion 21a, but lubricated at a position separated from the notch 94 along the axis of the rocker shaft 22. Since the oil passage 76 is disposed, the rigidity of the swing support portion 21a does not decrease even when the opening of the lubricating oil passage 76 and the cutout 94 are formed.

Further, between the first drive rocker arm 19 and the free rocker arm 21 adjacent to each other and between the second drive rocker arm 20 and the free rocker arm 21 adjacent to each other, the oil having the upper end opened at the upper part of each rocker arm 19 to 21 is provided. Since the grooves 96 are formed, it is not necessary to provide a special oil passage, and lubrication between the rocker arms 19, 21; 20, 21 can be performed by the scattered oil in the valve operating chamber.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

For example, in the above-described embodiment, the valve gear having the rocker arm supported to be rockable by the rocker shaft 22 has been described.
As disclosed in Japanese Patent Application Publication No. 0916, the present invention is also applicable to a valve gear in which one end of a rocker arm is pivotally supported by a pivot, and the present invention relates to the interlocking and interlocking of a plurality of rocker arms 19 to 21. Regardless of the presence or absence of the interlocking switching means 23 capable of switching the release, the present invention can be widely applied to a valve operating device of an internal combustion engine in which a rocker arm is interlocked and connected to a valve operating cam via a roller.

The present invention can also be applied to a structure in which pins 47 to 49 for fixing the support shafts 41 to 43 are press-fitted into the respective rocker arms 19 to 20, and in this case, the pins 47 to 49 are used. By connecting the lower connecting wall to the lower fixing portion, the rigidity of the rocker arms 19 to 21 receiving the press-fitting load when the pins 47 to 49 are press-fitted can be contributed. Further, the support member 22
The support member 22 may be provided directly on the cylinder head 11 or may be supported by a holder provided on the cylinder head 11.

[0092]

As described above, according to the first aspect of the present invention, the rigidity of the support shaft by the two support walls can be increased, and the rigidity of the entire rocker arm can be increased. , The oil can be once held, and the rotational resistance of the roller can be reduced. Moreover, the rocker arm does not become large due to the lower connecting wall.

Further, according to the second aspect of the present invention, it is possible to easily form a rocker arm having an optimum shape in consideration of an increase in rigidity and a reduction in weight.

According to the third aspect of the invention, the rigidity of the receiving portion to which the load is applied from the pressing means can be increased by the lower connecting wall.

According to the fourth aspect of the present invention, the spark plug insertion cylinder and the rocker arm can be arranged as close as possible to each other, which contributes to downsizing of the valve operating chamber and weight reduction of the rocker arm. It is possible to compensate for the lowering of the rigidity of the swing support portion due to the lower connecting wall.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a part of a valve train, and is a sectional view taken along line 1-1 of FIG. 2;

FIG. 2 is a plan view as viewed in the direction of arrow 2 in FIG.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

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

FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG. 2;

FIG. 6 is a cross-sectional view corresponding to FIG. 5 in a state before the pins are swaged.

FIG. 7 is a sectional view taken along line 7-7 of FIG. 2;

FIG. 8 is a sectional view taken along line 8-8 in FIG. 4;

FIG. 9 is a sectional view taken along line 9-9 of FIG. 2;

FIG. 10 is a sectional view taken along line 10-10 of FIG. 4;

FIG. 11 is a sectional view taken along line 11-11 of FIG. 10;

FIG. 12 is a plan view of the intake-side and exhaust-side valve trains.

FIG. 13 is a sectional view taken along line 13-13 of FIG. 12;

[Explanation of symbols]

17I, 17E: Valve operating device 18: Cam shaft 19, 20, 21: Rocker arm 19a, 20a, 21a: Swing support 22: Rocker shaft 25, 26 as a support member ..Valve cams 28, 29, 30... Rollers 31 ₁ , 31 ₂ , 32 ₁ , 32 ₂ , 33 ₁ , 33 _2.
Support wall portions 41, 42, 43 support shafts 44, 45, 46 insertion holes 47, 48, 49 pins 50, 51, 52 engagement grooves 53, 54, 55 ..Bearing 58 ... Lost motion mechanism as pressing means 85,87 ... Lower connecting wall 93 ... Ignition plug insertion tube 94 ... Notch

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshihiro Kamiyama 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside Honda R & D Co., Ltd. (72) Inventor Mamoru Kosuge 1-4-1 Chuo, Wako-shi, Saitama Honda R & D Co., Ltd.

Claims (4)

[Claims] A cam provided with a valve cam (25, 26).
On the shaft (18) and the cylinder head (11)
Swing support pivotably supported by the supported support member (22)
The swing support portions (19) are attached to the holding portions (19a, 20a, 21a).
a to 21a) spaced from each other in the direction along the swing axis
And a pair of support walls (31₁, 31_Two; 32₁,
32_Two33₁, 33_TwoB) where the base end of
Hook arms (19, 20, 21) and the two support walls
(31₁, 31_Two; 32₁, 32 _Two33₁, 33_Two)
A spindle (41, 42, 43) supported between the bearings
(53, 54, 55) through the support shafts (41 to 4).
3) is rotatably supported by the valve cam (2).
Rollers (28, 29, 3) that are in rolling contact with (5, 26)
0), the valve train for an internal combustion engine comprising:
Holding wall (31₁, 31 _Two; 32₁, 32_Two33₁, 3
3_Two) Lower connecting walls (85, 8)
7) opposes the lower outer peripheral surface of the rollers (28-30)
So that the swing support portions (19a to 21a)
A valve train for an internal combustion engine, which is provided. 2. The rocker arm (19, 20, 21).
2. The valve train of an internal combustion engine according to claim 1, wherein the valve is formed by metal injection molding. 3. The valve cam (2) is connected to the roller (30).
6) Pressing means (58) for urging the rocker arm (21) in the direction of rolling contact with the support shaft (4).
One of the support walls (33 ₁ , 33 ₂ ) is connected to one end of the lower connecting wall (87) along the axial direction of (3).
3. A valve train for an internal combustion engine according to claim 1, wherein said valve train is in contact with a receiving portion (62) projecting from a lower portion of said 3 ₂ ). 4. A portion of the rocker arm (21) which is opposed to the spark plug insertion tube (93) attached to the cylinder head (11) is provided on the swing support portion (21a) of the rocker arm (21). A concave notch (94) is provided on the opposite side, and at least a portion of the lower connecting wall (87) is provided.
The internal combustion engine according to any one of claims 1 to 3, wherein at least a part of the notch (94) is disposed on a same plane orthogonal to a swing axis of the rocker arm (21). Valve train.